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rk3288 tinker board no videoX device #6

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zillevdr opened this issue Mar 19, 2017 · 1 comment
Closed

rk3288 tinker board no videoX device #6

zillevdr opened this issue Mar 19, 2017 · 1 comment

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@zillevdr
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Hello,

with branch release-4.4 configured with rockchip_linux_defconfig I get no /dev/videoX device. With kernel from TinderOS is there video0 and video1.
This is dmesg:

dmesg.txt

Regards zillevdr

@wzyy2
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wzyy2 commented Mar 20, 2017

They are replaced with /dev/vpu_service and /dev/hevc_service.

@wzyy2 wzyy2 closed this as completed Mar 20, 2017
Kwiboo referenced this issue in Kwiboo/linux-rockchip May 2, 2017
mipsxx_pmu_handle_shared_irq() calls irq_work_run() while holding the
pmuint_rwlock for read.  irq_work_run() can, via perf_pending_event(),
call try_to_wake_up() which can try to take rq->lock.

However, perf can also call perf_pmu_enable() (and thus take the
pmuint_rwlock for write) while holding the rq->lock, from
finish_task_switch() via perf_event_context_sched_in().

This leads to an ABBA deadlock:

 PID: 3855   TASK: 8f7ce288  CPU: 2   COMMAND: "process"
  #0 [89c39ac8] __delay at 803b5be4
  #1 [89c39ac8] do_raw_spin_lock at 8008fdcc
  #2 [89c39af8] try_to_wake_up at 8006e47c
  #3 [89c39b38] pollwake at 8018eab0
  #4 [89c39b68] __wake_up_common at 800879f4
  #5 [89c39b98] __wake_up at 800880e4
  #6 [89c39bc8] perf_event_wakeup at 8012109c
  #7 [89c39be8] perf_pending_event at 80121184
  #8 [89c39c08] irq_work_run_list at 801151f0
  #9 [89c39c38] irq_work_run at 80115274
 #10 [89c39c50] mipsxx_pmu_handle_shared_irq at 8002cc7c

 PID: 1481   TASK: 8eaac6a8  CPU: 3   COMMAND: "process"
  #0 [8de7f900] do_raw_write_lock at 800900e0
  #1 [8de7f918] perf_event_context_sched_in at 80122310
  #2 [8de7f938] __perf_event_task_sched_in at 80122608
  #3 [8de7f958] finish_task_switch at 8006b8a4
  #4 [8de7f998] __schedule at 805e4dc4
  #5 [8de7f9f8] schedule at 805e5558
  #6 [8de7fa10] schedule_hrtimeout_range_clock at 805e9984
  #7 [8de7fa70] poll_schedule_timeout at 8018e8f8
  #8 [8de7fa88] do_select at 8018f338
  #9 [8de7fd88] core_sys_select at 8018f5cc
 #10 [8de7fee0] sys_select at 8018f854
 #11 [8de7ff28] syscall_common at 80028fc8

The lock seems to be there to protect the hardware counters so there is
no need to hold it across irq_work_run().

Signed-off-by: Rabin Vincent <[email protected]>
Signed-off-by: Ralf Baechle <[email protected]>
Kwiboo referenced this issue in Kwiboo/linux-rockchip May 2, 2017
keep tty driver until usb driver is unregistered
rmmod hso
produces traces like this without that:

[40261.645904] usb 2-2: new high-speed USB device number 2 using ehci-omap
[40261.854644] usb 2-2: New USB device found, idVendor=0af0, idProduct=8800
[40261.862609] usb 2-2: New USB device strings: Mfr=3, Product=2, SerialNumber=0
[40261.872772] usb 2-2: Product: Globetrotter HSUPA Modem
[40261.880279] usb 2-2: Manufacturer: Option N.V.
[40262.021270] hso 2-2:1.5: Not our interface
[40265.556945] hso: unloaded
[40265.559875] usbcore: deregistering interface driver hso
[40265.595947] Unable to handle kernel NULL pointer dereference at virtual address 00000033
[40265.604522] pgd = ecb14000
[40265.611877] [00000033] *pgd=00000000
[40265.617034] Internal error: Oops: 5 [#1] PREEMPT SMP ARM
[40265.622650] Modules linked in: hso(-) bnep bluetooth ipv6 arc4 twl4030_madc_hwmon wl18xx wlcore mac80211 cfg80211 snd_soc_simple_card snd_soc_simple_card_utils snd_soc_omap_twl4030 snd_soc_gtm601 generic_adc_battery extcon_gpio omap3_isp videobuf2_dma_contig videobuf2_memops wlcore_sdio videobuf2_v4l2 videobuf2_core ov9650 bmp280_i2c v4l2_common bmp280 bmg160_i2c bmg160_core at24 nvmem_core videodev bmc150_accel_i2c bmc150_magn_i2c media bmc150_accel_core tsc2007 bmc150_magn leds_tca6507 bno055 snd_soc_omap_mcbsp industrialio_triggered_buffer snd_soc_omap kfifo_buf snd_pcm_dmaengine gpio_twl4030 snd_soc_twl4030 twl4030_vibra twl4030_madc wwan_on_off ehci_omap pwm_bl pwm_omap_dmtimer panel_tpo_td028ttec1 encoder_opa362 connector_analog_tv omapdrm drm_kms_helper cfbfillrect syscopyarea cfbimgblt sysfillrect
[40265.698211]  sysimgblt fb_sys_fops cfbcopyarea drm omapdss usb_f_ecm g_ether usb_f_rndis u_ether libcomposite configfs omap2430 phy_twl4030_usb musb_hdrc twl4030_charger industrialio w2sg0004 twl4030_pwrbutton bq27xxx_battery w1_bq27000 omap_hdq [last unloaded: hso]
[40265.723175] CPU: 0 PID: 2701 Comm: rmmod Not tainted 4.11.0-rc6-letux+ #6
[40265.730346] Hardware name: Generic OMAP36xx (Flattened Device Tree)
[40265.736938] task: ecb81100 task.stack: ecb82000
[40265.741729] PC is at cdev_del+0xc/0x2c
[40265.745666] LR is at tty_unregister_device+0x40/0x50
[40265.750915] pc : [<c027472c>]    lr : [<c04b3ecc>]    psr: 600b0113
sp : ecb83ea8  ip : eca4f898  fp : 00000000
[40265.763000] r10: 00000000  r9 : 00000000  r8 : 00000001
[40265.768493] r7 : eca4f800  r6 : 00000003  r5 : 00000000  r4 : ffffffff
[40265.775360] r3 : c1458d54  r2 : 00000000  r1 : 00000004  r0 : ffffffff
[40265.782257] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
[40265.789764] Control: 10c5387d  Table: acb14019  DAC: 00000051
[40265.795806] Process rmmod (pid: 2701, stack limit = 0xecb82218)
[40265.802062] Stack: (0xecb83ea8 to 0xecb84000)
[40265.806640] 3ea0:                   ec9e8100 c04b3ecc bf737378 ed5b7c00 00000003 bf7327ec
[40265.815277] 3ec0: eca4f800 00000000 ec9fd800 eca4f800 bf737070 bf7328bc eca4f820 c05a9a04
[40265.823883] 3ee0: eca4f820 00000000 00000001 eca4f820 ec9fd870 bf737070 eca4f854 ec9fd8a4
[40265.832519] 3f00: ecb82000 00000000 00000000 c04e6960 eca4f820 bf737070 bf737048 00000081
[40265.841125] 3f20: c01071e4 c04e6a60 ecb81100 bf737070 bf737070 c04e5d94 bf737020 c05a8f88
[40265.849731] 3f40: bf737100 00000800 7f5fa254 00000081 c01071e4 c01c4afc 00000000 006f7368
[40265.858367] 3f60: ecb815f4 00000000 c0cac9c4 c01071e4 ecb82000 00000000 00000000 c01512f4
[40265.866973] 3f80: ed5b3200 c01071e4 7f5fa220 7f5fa220 bea78ec9 0010711c 7f5fa220 7f5fa220
[40265.875579] 3fa0: bea78ec9 c0107040 7f5fa220 7f5fa220 7f5fa254 00000800 dd35b800 dd35b800
[40265.884216] 3fc0: 7f5fa220 7f5fa220 bea78ec9 00000081 bea78dcc 00000000 bea78bd8 00000000
[40265.892822] 3fe0: b6f70521 bea78b6c 7f5dd613 b6f70526 80070030 7f5fa254 ffffffff ffffffff
[40265.901458] [<c027472c>] (cdev_del) from [<c04b3ecc>] (tty_unregister_device+0x40/0x50)
[40265.909942] [<c04b3ecc>] (tty_unregister_device) from [<bf7327ec>] (hso_free_interface+0x80/0x144 [hso])
[40265.919982] [<bf7327ec>] (hso_free_interface [hso]) from [<bf7328bc>] (hso_disconnect+0xc/0x18 [hso])
[40265.929718] [<bf7328bc>] (hso_disconnect [hso]) from [<c05a9a04>] (usb_unbind_interface+0x84/0x200)
[40265.939239] [<c05a9a04>] (usb_unbind_interface) from [<c04e6960>] (device_release_driver_internal+0x138/0x1cc)
[40265.949798] [<c04e6960>] (device_release_driver_internal) from [<c04e6a60>] (driver_detach+0x60/0x6c)
[40265.959503] [<c04e6a60>] (driver_detach) from [<c04e5d94>] (bus_remove_driver+0x64/0x8c)
[40265.968017] [<c04e5d94>] (bus_remove_driver) from [<c05a8f88>] (usb_deregister+0x5c/0xb8)
[40265.976654] [<c05a8f88>] (usb_deregister) from [<c01c4afc>] (SyS_delete_module+0x160/0x1dc)
[40265.985443] [<c01c4afc>] (SyS_delete_module) from [<c0107040>] (ret_fast_syscall+0x0/0x1c)
[40265.994171] Code: c1458d54 e59f3020 e92d4010 e1a04000 (e5941034)
[40266.016693] ---[ end trace 9d5ac43c7e41075c ]---

Signed-off-by: Andreas Kemnade <[email protected]>
Reviewed-by: Johan Hovold <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
wzyy2 pushed a commit that referenced this issue Aug 10, 2017
[ Upstream commit 9745e36 ]

The register_vlan_device would invoke free_netdev directly, when
register_vlan_dev failed. It would trigger the BUG_ON in free_netdev
if the dev was already registered. In this case, the netdev would be
freed in netdev_run_todo later.

So add one condition check now. Only when dev is not registered, then
free it directly.

The following is the part coredump when netdev_upper_dev_link failed
in register_vlan_dev. I removed the lines which are too long.

[  411.237457] ------------[ cut here ]------------
[  411.237458] kernel BUG at net/core/dev.c:7998!
[  411.237484] invalid opcode: 0000 [#1] SMP
[  411.237705]  [last unloaded: 8021q]
[  411.237718] CPU: 1 PID: 12845 Comm: vconfig Tainted: G            E   4.12.0-rc5+ #6
[  411.237737] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/02/2015
[  411.237764] task: ffff9cbeb6685580 task.stack: ffffa7d2807d8000
[  411.237782] RIP: 0010:free_netdev+0x116/0x120
[  411.237794] RSP: 0018:ffffa7d2807dbdb0 EFLAGS: 00010297
[  411.237808] RAX: 0000000000000002 RBX: ffff9cbeb6ba8fd8 RCX: 0000000000001878
[  411.237826] RDX: 0000000000000001 RSI: 0000000000000282 RDI: 0000000000000000
[  411.237844] RBP: ffffa7d2807dbdc8 R08: 0002986100029841 R09: 0002982100029801
[  411.237861] R10: 0004000100029980 R11: 0004000100029980 R12: ffff9cbeb6ba9000
[  411.238761] R13: ffff9cbeb6ba9060 R14: ffff9cbe60f1a000 R15: ffff9cbeb6ba9000
[  411.239518] FS:  00007fb690d81700(0000) GS:ffff9cbebb640000(0000) knlGS:0000000000000000
[  411.239949] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  411.240454] CR2: 00007f7115624000 CR3: 0000000077cdf000 CR4: 00000000003406e0
[  411.240936] Call Trace:
[  411.241462]  vlan_ioctl_handler+0x3f1/0x400 [8021q]
[  411.241910]  sock_ioctl+0x18b/0x2c0
[  411.242394]  do_vfs_ioctl+0xa1/0x5d0
[  411.242853]  ? sock_alloc_file+0xa6/0x130
[  411.243465]  SyS_ioctl+0x79/0x90
[  411.243900]  entry_SYSCALL_64_fastpath+0x1e/0xa9
[  411.244425] RIP: 0033:0x7fb69089a357
[  411.244863] RSP: 002b:00007ffcd04e0fc8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
[  411.245445] RAX: ffffffffffffffda RBX: 00007ffcd04e2884 RCX: 00007fb69089a357
[  411.245903] RDX: 00007ffcd04e0fd0 RSI: 0000000000008983 RDI: 0000000000000003
[  411.246527] RBP: 00007ffcd04e0fd0 R08: 0000000000000000 R09: 1999999999999999
[  411.246976] R10: 000000000000053f R11: 0000000000000202 R12: 0000000000000004
[  411.247414] R13: 00007ffcd04e1128 R14: 00007ffcd04e2888 R15: 0000000000000001
[  411.249129] RIP: free_netdev+0x116/0x120 RSP: ffffa7d2807dbdb0

Signed-off-by: Gao Feng <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
wzyy2 pushed a commit that referenced this issue Sep 22, 2017
commit cdea465 upstream.

A vendor with a system having more than 128 CPUs occasionally encounters
the following crash during shutdown. This is not an easily reproduceable
event, but the vendor was able to provide the following analysis of the
crash, which exhibits the same footprint each time.

crash> bt
PID: 0      TASK: ffff88017c70ce70  CPU: 5   COMMAND: "swapper/5"
 #0 [ffff88085c143ac8] machine_kexec at ffffffff81059c8b
 #1 [ffff88085c143b28] __crash_kexec at ffffffff811052e2
 #2 [ffff88085c143bf8] crash_kexec at ffffffff811053d0
 #3 [ffff88085c143c10] oops_end at ffffffff8168ef88
 #4 [ffff88085c143c38] no_context at ffffffff8167ebb3
 #5 [ffff88085c143c88] __bad_area_nosemaphore at ffffffff8167ec49
 #6 [ffff88085c143cd0] bad_area_nosemaphore at ffffffff8167edb3
 #7 [ffff88085c143ce0] __do_page_fault at ffffffff81691d1e
 #8 [ffff88085c143d40] do_page_fault at ffffffff81691ec5
 #9 [ffff88085c143d70] page_fault at ffffffff8168e188
    [exception RIP: unknown or invalid address]
    RIP: ffffffffa053c800  RSP: ffff88085c143e28  RFLAGS: 00010206
    RAX: ffff88017c72bfd8  RBX: ffff88017a8dc000  RCX: ffff8810588b5ac8
    RDX: ffff8810588b5a00  RSI: ffffffffa053c800  RDI: ffff8810588b5a00
    RBP: ffff88085c143e58   R8: ffff88017c70d408   R9: ffff88017a8dc000
    R10: 0000000000000002  R11: ffff88085c143da0  R12: ffff8810588b5ac8
    R13: 0000000000000100  R14: ffffffffa053c800  R15: ffff8810588b5a00
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
    <IRQ stack>
    [exception RIP: cpuidle_enter_state+82]
    RIP: ffffffff81514192  RSP: ffff88017c72be50  RFLAGS: 00000202
    RAX: 0000001e4c3c6f16  RBX: 000000000000f8a0  RCX: 0000000000000018
    RDX: 0000000225c17d03  RSI: ffff88017c72bfd8  RDI: 0000001e4c3c6f16
    RBP: ffff88017c72be78   R8: 000000000000237e   R9: 0000000000000018
    R10: 0000000000002494  R11: 0000000000000001  R12: ffff88017c72be20
    R13: ffff88085c14f8e0  R14: 0000000000000082  R15: 0000001e4c3bb400
    ORIG_RAX: ffffffffffffff10  CS: 0010  SS: 0018

This is the corresponding stack trace

It has crashed because the area pointed with RIP extracted from timer
element is already removed during a shutdown process.

The function is smi_timeout().

And we think ffff8810588b5a00 in RDX is a parameter struct smi_info

crash> rd ffff8810588b5a00 20
ffff8810588b5a00:  ffff8810588b6000 0000000000000000   .`.X............
ffff8810588b5a10:  ffff880853264400 ffffffffa05417e0   .D&S......T.....
ffff8810588b5a20:  24a024a000000000 0000000000000000   .....$.$........
ffff8810588b5a30:  0000000000000000 0000000000000000   ................
ffff8810588b5a30:  0000000000000000 0000000000000000   ................
ffff8810588b5a40:  ffffffffa053a040 ffffffffa053a060   @.S.....`.S.....
ffff8810588b5a50:  0000000000000000 0000000100000001   ................
ffff8810588b5a60:  0000000000000000 0000000000000e00   ................
ffff8810588b5a70:  ffffffffa053a580 ffffffffa053a6e0   ..S.......S.....
ffff8810588b5a80:  ffffffffa053a4a0 ffffffffa053a250   ..S.....P.S.....
ffff8810588b5a90:  0000000500000002 0000000000000000   ................

Unfortunately the top of this area is already detroyed by someone.
But because of two reasonns we think this is struct smi_info
 1) The address included in between  ffff8810588b5a70 and ffff8810588b5a80:
  are inside of ipmi_si_intf.c  see crash> module ffff88085779d2c0

 2) We've found the area which point this.
  It is offset 0x68 of  ffff880859df4000

crash> rd  ffff880859df4000 100
ffff880859df4000:  0000000000000000 0000000000000001   ................
ffff880859df4010:  ffffffffa0535290 dead000000000200   .RS.............
ffff880859df4020:  ffff880859df4020 ffff880859df4020    @.Y.... @.Y....
ffff880859df4030:  0000000000000002 0000000000100010   ................
ffff880859df4040:  ffff880859df4040 ffff880859df4040   @@.Y....@@.Y....
ffff880859df4050:  0000000000000000 0000000000000000   ................
ffff880859df4060:  0000000000000000 ffff8810588b5a00   .........Z.X....
ffff880859df4070:  0000000000000001 ffff880859df4078   [email protected]....

 If we regards it as struct ipmi_smi in shutdown process
 it looks consistent.

The remedy for this apparent race is affixed below.

Signed-off-by: Tony Camuso <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

This was first introduced in 7ea0ed2 ipmi: Make the
message handler easier to use for SMI interfaces
where some code was moved outside of the rcu_read_lock()
and the lock was not added.

Signed-off-by: Corey Minyard <[email protected]>
wzyy2 pushed a commit that referenced this issue Jan 30, 2018
[ Upstream commit ec4fbd6 ]

Dmitry reported a lockdep splat [1] (false positive) that we can fix
by releasing the spinlock before calling icmp_send() from ip_expire()

This is a false positive because sending an ICMP message can not
possibly re-enter the IP frag engine.

[1]
[ INFO: possible circular locking dependency detected ]
4.10.0+ #29 Not tainted
-------------------------------------------------------
modprobe/12392 is trying to acquire lock:
 (_xmit_ETHER#2){+.-...}, at: [<ffffffff837a8182>] spin_lock
include/linux/spinlock.h:299 [inline]
 (_xmit_ETHER#2){+.-...}, at: [<ffffffff837a8182>] __netif_tx_lock
include/linux/netdevice.h:3486 [inline]
 (_xmit_ETHER#2){+.-...}, at: [<ffffffff837a8182>]
sch_direct_xmit+0x282/0x6d0 net/sched/sch_generic.c:180

but task is already holding lock:
 (&(&q->lock)->rlock){+.-...}, at: [<ffffffff8389a4d1>] spin_lock
include/linux/spinlock.h:299 [inline]
 (&(&q->lock)->rlock){+.-...}, at: [<ffffffff8389a4d1>]
ip_expire+0x51/0x6c0 net/ipv4/ip_fragment.c:201

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&(&q->lock)->rlock){+.-...}:
       validate_chain kernel/locking/lockdep.c:2267 [inline]
       __lock_acquire+0x2149/0x3430 kernel/locking/lockdep.c:3340
       lock_acquire+0x2a1/0x630 kernel/locking/lockdep.c:3755
       __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
       _raw_spin_lock+0x33/0x50 kernel/locking/spinlock.c:151
       spin_lock include/linux/spinlock.h:299 [inline]
       ip_defrag+0x3a2/0x4130 net/ipv4/ip_fragment.c:669
       ip_check_defrag+0x4e3/0x8b0 net/ipv4/ip_fragment.c:713
       packet_rcv_fanout+0x282/0x800 net/packet/af_packet.c:1459
       deliver_skb net/core/dev.c:1834 [inline]
       dev_queue_xmit_nit+0x294/0xa90 net/core/dev.c:1890
       xmit_one net/core/dev.c:2903 [inline]
       dev_hard_start_xmit+0x16b/0xab0 net/core/dev.c:2923
       sch_direct_xmit+0x31f/0x6d0 net/sched/sch_generic.c:182
       __dev_xmit_skb net/core/dev.c:3092 [inline]
       __dev_queue_xmit+0x13e5/0x1e60 net/core/dev.c:3358
       dev_queue_xmit+0x17/0x20 net/core/dev.c:3423
       neigh_resolve_output+0x6b9/0xb10 net/core/neighbour.c:1308
       neigh_output include/net/neighbour.h:478 [inline]
       ip_finish_output2+0x8b8/0x15a0 net/ipv4/ip_output.c:228
       ip_do_fragment+0x1d93/0x2720 net/ipv4/ip_output.c:672
       ip_fragment.constprop.54+0x145/0x200 net/ipv4/ip_output.c:545
       ip_finish_output+0x82d/0xe10 net/ipv4/ip_output.c:314
       NF_HOOK_COND include/linux/netfilter.h:246 [inline]
       ip_output+0x1f0/0x7a0 net/ipv4/ip_output.c:404
       dst_output include/net/dst.h:486 [inline]
       ip_local_out+0x95/0x170 net/ipv4/ip_output.c:124
       ip_send_skb+0x3c/0xc0 net/ipv4/ip_output.c:1492
       ip_push_pending_frames+0x64/0x80 net/ipv4/ip_output.c:1512
       raw_sendmsg+0x26de/0x3a00 net/ipv4/raw.c:655
       inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:761
       sock_sendmsg_nosec net/socket.c:633 [inline]
       sock_sendmsg+0xca/0x110 net/socket.c:643
       ___sys_sendmsg+0x4a3/0x9f0 net/socket.c:1985
       __sys_sendmmsg+0x25c/0x750 net/socket.c:2075
       SYSC_sendmmsg net/socket.c:2106 [inline]
       SyS_sendmmsg+0x35/0x60 net/socket.c:2101
       do_syscall_64+0x2e8/0x930 arch/x86/entry/common.c:281
       return_from_SYSCALL_64+0x0/0x7a

-> #0 (_xmit_ETHER#2){+.-...}:
       check_prev_add kernel/locking/lockdep.c:1830 [inline]
       check_prevs_add+0xa8f/0x19f0 kernel/locking/lockdep.c:1940
       validate_chain kernel/locking/lockdep.c:2267 [inline]
       __lock_acquire+0x2149/0x3430 kernel/locking/lockdep.c:3340
       lock_acquire+0x2a1/0x630 kernel/locking/lockdep.c:3755
       __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
       _raw_spin_lock+0x33/0x50 kernel/locking/spinlock.c:151
       spin_lock include/linux/spinlock.h:299 [inline]
       __netif_tx_lock include/linux/netdevice.h:3486 [inline]
       sch_direct_xmit+0x282/0x6d0 net/sched/sch_generic.c:180
       __dev_xmit_skb net/core/dev.c:3092 [inline]
       __dev_queue_xmit+0x13e5/0x1e60 net/core/dev.c:3358
       dev_queue_xmit+0x17/0x20 net/core/dev.c:3423
       neigh_hh_output include/net/neighbour.h:468 [inline]
       neigh_output include/net/neighbour.h:476 [inline]
       ip_finish_output2+0xf6c/0x15a0 net/ipv4/ip_output.c:228
       ip_finish_output+0xa29/0xe10 net/ipv4/ip_output.c:316
       NF_HOOK_COND include/linux/netfilter.h:246 [inline]
       ip_output+0x1f0/0x7a0 net/ipv4/ip_output.c:404
       dst_output include/net/dst.h:486 [inline]
       ip_local_out+0x95/0x170 net/ipv4/ip_output.c:124
       ip_send_skb+0x3c/0xc0 net/ipv4/ip_output.c:1492
       ip_push_pending_frames+0x64/0x80 net/ipv4/ip_output.c:1512
       icmp_push_reply+0x372/0x4d0 net/ipv4/icmp.c:394
       icmp_send+0x156c/0x1c80 net/ipv4/icmp.c:754
       ip_expire+0x40e/0x6c0 net/ipv4/ip_fragment.c:239
       call_timer_fn+0x241/0x820 kernel/time/timer.c:1268
       expire_timers kernel/time/timer.c:1307 [inline]
       __run_timers+0x960/0xcf0 kernel/time/timer.c:1601
       run_timer_softirq+0x21/0x80 kernel/time/timer.c:1614
       __do_softirq+0x31f/0xbe7 kernel/softirq.c:284
       invoke_softirq kernel/softirq.c:364 [inline]
       irq_exit+0x1cc/0x200 kernel/softirq.c:405
       exiting_irq arch/x86/include/asm/apic.h:657 [inline]
       smp_apic_timer_interrupt+0x76/0xa0 arch/x86/kernel/apic/apic.c:962
       apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:707
       __read_once_size include/linux/compiler.h:254 [inline]
       atomic_read arch/x86/include/asm/atomic.h:26 [inline]
       rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:350 [inline]
       __rcu_is_watching kernel/rcu/tree.c:1133 [inline]
       rcu_is_watching+0x83/0x110 kernel/rcu/tree.c:1147
       rcu_read_lock_held+0x87/0xc0 kernel/rcu/update.c:293
       radix_tree_deref_slot include/linux/radix-tree.h:238 [inline]
       filemap_map_pages+0x6d4/0x1570 mm/filemap.c:2335
       do_fault_around mm/memory.c:3231 [inline]
       do_read_fault mm/memory.c:3265 [inline]
       do_fault+0xbd5/0x2080 mm/memory.c:3370
       handle_pte_fault mm/memory.c:3600 [inline]
       __handle_mm_fault+0x1062/0x2cb0 mm/memory.c:3714
       handle_mm_fault+0x1e2/0x480 mm/memory.c:3751
       __do_page_fault+0x4f6/0xb60 arch/x86/mm/fault.c:1397
       do_page_fault+0x54/0x70 arch/x86/mm/fault.c:1460
       page_fault+0x28/0x30 arch/x86/entry/entry_64.S:1011

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&(&q->lock)->rlock);
                               lock(_xmit_ETHER#2);
                               lock(&(&q->lock)->rlock);
  lock(_xmit_ETHER#2);

 *** DEADLOCK ***

10 locks held by modprobe/12392:
 #0:  (&mm->mmap_sem){++++++}, at: [<ffffffff81329758>]
__do_page_fault+0x2b8/0xb60 arch/x86/mm/fault.c:1336
 #1:  (rcu_read_lock){......}, at: [<ffffffff8188cab6>]
filemap_map_pages+0x1e6/0x1570 mm/filemap.c:2324
 #2:  (&(ptlock_ptr(page))->rlock#2){+.+...}, at: [<ffffffff81984a78>]
spin_lock include/linux/spinlock.h:299 [inline]
 #2:  (&(ptlock_ptr(page))->rlock#2){+.+...}, at: [<ffffffff81984a78>]
pte_alloc_one_map mm/memory.c:2944 [inline]
 #2:  (&(ptlock_ptr(page))->rlock#2){+.+...}, at: [<ffffffff81984a78>]
alloc_set_pte+0x13b8/0x1b90 mm/memory.c:3072
 #3:  (((&q->timer))){+.-...}, at: [<ffffffff81627e72>]
lockdep_copy_map include/linux/lockdep.h:175 [inline]
 #3:  (((&q->timer))){+.-...}, at: [<ffffffff81627e72>]
call_timer_fn+0x1c2/0x820 kernel/time/timer.c:1258
 #4:  (&(&q->lock)->rlock){+.-...}, at: [<ffffffff8389a4d1>] spin_lock
include/linux/spinlock.h:299 [inline]
 #4:  (&(&q->lock)->rlock){+.-...}, at: [<ffffffff8389a4d1>]
ip_expire+0x51/0x6c0 net/ipv4/ip_fragment.c:201
 #5:  (rcu_read_lock){......}, at: [<ffffffff8389a633>]
ip_expire+0x1b3/0x6c0 net/ipv4/ip_fragment.c:216
 #6:  (slock-AF_INET){+.-...}, at: [<ffffffff839b3313>] spin_trylock
include/linux/spinlock.h:309 [inline]
 #6:  (slock-AF_INET){+.-...}, at: [<ffffffff839b3313>] icmp_xmit_lock
net/ipv4/icmp.c:219 [inline]
 #6:  (slock-AF_INET){+.-...}, at: [<ffffffff839b3313>]
icmp_send+0x803/0x1c80 net/ipv4/icmp.c:681
 #7:  (rcu_read_lock_bh){......}, at: [<ffffffff838ab9a1>]
ip_finish_output2+0x2c1/0x15a0 net/ipv4/ip_output.c:198
 #8:  (rcu_read_lock_bh){......}, at: [<ffffffff836d1dee>]
__dev_queue_xmit+0x23e/0x1e60 net/core/dev.c:3324
 #9:  (dev->qdisc_running_key ?: &qdisc_running_key){+.....}, at:
[<ffffffff836d3a27>] dev_queue_xmit+0x17/0x20 net/core/dev.c:3423

stack backtrace:
CPU: 0 PID: 12392 Comm: modprobe Not tainted 4.10.0+ #29
Hardware name: Google Google Compute Engine/Google Compute Engine,
BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x2ee/0x3ef lib/dump_stack.c:52
 print_circular_bug+0x307/0x3b0 kernel/locking/lockdep.c:1204
 check_prev_add kernel/locking/lockdep.c:1830 [inline]
 check_prevs_add+0xa8f/0x19f0 kernel/locking/lockdep.c:1940
 validate_chain kernel/locking/lockdep.c:2267 [inline]
 __lock_acquire+0x2149/0x3430 kernel/locking/lockdep.c:3340
 lock_acquire+0x2a1/0x630 kernel/locking/lockdep.c:3755
 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_lock+0x33/0x50 kernel/locking/spinlock.c:151
 spin_lock include/linux/spinlock.h:299 [inline]
 __netif_tx_lock include/linux/netdevice.h:3486 [inline]
 sch_direct_xmit+0x282/0x6d0 net/sched/sch_generic.c:180
 __dev_xmit_skb net/core/dev.c:3092 [inline]
 __dev_queue_xmit+0x13e5/0x1e60 net/core/dev.c:3358
 dev_queue_xmit+0x17/0x20 net/core/dev.c:3423
 neigh_hh_output include/net/neighbour.h:468 [inline]
 neigh_output include/net/neighbour.h:476 [inline]
 ip_finish_output2+0xf6c/0x15a0 net/ipv4/ip_output.c:228
 ip_finish_output+0xa29/0xe10 net/ipv4/ip_output.c:316
 NF_HOOK_COND include/linux/netfilter.h:246 [inline]
 ip_output+0x1f0/0x7a0 net/ipv4/ip_output.c:404
 dst_output include/net/dst.h:486 [inline]
 ip_local_out+0x95/0x170 net/ipv4/ip_output.c:124
 ip_send_skb+0x3c/0xc0 net/ipv4/ip_output.c:1492
 ip_push_pending_frames+0x64/0x80 net/ipv4/ip_output.c:1512
 icmp_push_reply+0x372/0x4d0 net/ipv4/icmp.c:394
 icmp_send+0x156c/0x1c80 net/ipv4/icmp.c:754
 ip_expire+0x40e/0x6c0 net/ipv4/ip_fragment.c:239
 call_timer_fn+0x241/0x820 kernel/time/timer.c:1268
 expire_timers kernel/time/timer.c:1307 [inline]
 __run_timers+0x960/0xcf0 kernel/time/timer.c:1601
 run_timer_softirq+0x21/0x80 kernel/time/timer.c:1614
 __do_softirq+0x31f/0xbe7 kernel/softirq.c:284
 invoke_softirq kernel/softirq.c:364 [inline]
 irq_exit+0x1cc/0x200 kernel/softirq.c:405
 exiting_irq arch/x86/include/asm/apic.h:657 [inline]
 smp_apic_timer_interrupt+0x76/0xa0 arch/x86/kernel/apic/apic.c:962
 apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:707
RIP: 0010:__read_once_size include/linux/compiler.h:254 [inline]
RIP: 0010:atomic_read arch/x86/include/asm/atomic.h:26 [inline]
RIP: 0010:rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:350 [inline]
RIP: 0010:__rcu_is_watching kernel/rcu/tree.c:1133 [inline]
RIP: 0010:rcu_is_watching+0x83/0x110 kernel/rcu/tree.c:1147
RSP: 0000:ffff8801c391f120 EFLAGS: 00000a03 ORIG_RAX: ffffffffffffff10
RAX: dffffc0000000000 RBX: ffff8801c391f148 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 000055edd4374000 RDI: ffff8801dbe1ae0c
RBP: ffff8801c391f1a0 R08: 0000000000000002 R09: 0000000000000000
R10: dffffc0000000000 R11: 0000000000000002 R12: 1ffff10038723e25
R13: ffff8801dbe1ae00 R14: ffff8801c391f680 R15: dffffc0000000000
 </IRQ>
 rcu_read_lock_held+0x87/0xc0 kernel/rcu/update.c:293
 radix_tree_deref_slot include/linux/radix-tree.h:238 [inline]
 filemap_map_pages+0x6d4/0x1570 mm/filemap.c:2335
 do_fault_around mm/memory.c:3231 [inline]
 do_read_fault mm/memory.c:3265 [inline]
 do_fault+0xbd5/0x2080 mm/memory.c:3370
 handle_pte_fault mm/memory.c:3600 [inline]
 __handle_mm_fault+0x1062/0x2cb0 mm/memory.c:3714
 handle_mm_fault+0x1e2/0x480 mm/memory.c:3751
 __do_page_fault+0x4f6/0xb60 arch/x86/mm/fault.c:1397
 do_page_fault+0x54/0x70 arch/x86/mm/fault.c:1460
 page_fault+0x28/0x30 arch/x86/entry/entry_64.S:1011
RIP: 0033:0x7f83172f2786
RSP: 002b:00007fffe859ae80 EFLAGS: 00010293
RAX: 000055edd4373040 RBX: 00007f83175111c8 RCX: 000055edd4373238
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007f8317510970
RBP: 00007fffe859afd0 R08: 0000000000000009 R09: 0000000000000000
R10: 0000000000000064 R11: 0000000000000000 R12: 000055edd4373040
R13: 0000000000000000 R14: 00007fffe859afe8 R15: 0000000000000000

Signed-off-by: Eric Dumazet <[email protected]>
Reported-by: Dmitry Vyukov <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
rkchrome pushed a commit that referenced this issue Apr 10, 2018
According to the dwc2 programmer's guide v3.10a, in '2.1.3.2 Dedicated
FIFO Mode with No Thresholding', it suggested that:

Device RxFIFO =
- Scatter/Gather DMA mode:
(4 * number of control endpoints + 6) + ((largest USB packet used / 4) +
1 for status information) + (2 * number of OUT endpoints) + 1 for Global NAK

on rockchip platforms:
(4 * 1 + 6) + ((1024 / 4) + 1) + (2 * 6) + 1 = 280

- Slave or Buffer DMA mode:
(5 * number of control endpoints + 8) + ((largest USB packet used / 4) +
1 for status information) + (2 * number of OUT endpoints) + 1 for Global NAK

on rockchip platforms:
(5 * 1 + 8) + ((1024 / 4) + 1) + (2 * 6) + 1 = 283

Device IN Endpoint TxFIFO =
The TxFIFO must equal at least one MaxPacketSize (MPS).

In addition to RxFIFO and TxFIFOs, refer to dwc2 databook v3.10a,
'Figure 2-13 Device Mode FIFO Address Mapping and AHB FIFO Access Mapping
(Dedicated FIFO)', it required that when the device is operating in non
Scatter Gather Internal DMA mode, the last locations of the SPRAM are used
to store the DMAADDR values for each Endpoint (1 location per endpoint).

When the device is operating in Scatter Gather mode, then the last locations
of the SPRAM store the Base Descriptor address, Current Descriptor address,
Current Buffer address, and status quadlet information for each endpoint
direction (4 locations per Endpoint). If an Endpoint is bidirectional , then
4 locations will be used for IN, and another 4 for OUT).

Considering that the total FIFO size of dwc2 otg is 0x3cc (972),
and we must reserve (4 * 13) = 52 locations for all Endpoints.
So reconfig dwc2 device fifo size as follows:

Device RxFIFO = 280
Device IN Endpoint TxFIFO
- FIFO #0 = (64 / 4) = 16 (Assuming this is used for EP0)
- FIFO #1 = (1024/4) = 256 (Assuming this is used for Isochronous)
- FIFO #2 = (512/4) = 128
- FIFO #3 = (512/4) = 128
- FIFO #4 = (256/4) = 64
- FIFO #5 = (128/4) = 32
- FIFO #6 = (64/4) = 16

After reconfig the dwc2 device fifo size, test mtp write on rockchip
platform (PC -> rockchip platform) on rk312x/rk3326/px30/rk3288 evb,
when mask the 'vfs_write' in f_mtp.c, the writing data rate can be
increased from 16MBps ~ 20MBps to 30MBps ~ 36MBps on different kinds
of rockchip evbs.

Change-Id: Icdf8a5dd95f96d174233e4ffc765c9a982b9f0b6
Signed-off-by: William Wu <[email protected]>
rkchrome pushed a commit that referenced this issue Apr 10, 2018
According to the dwc2 programmer's guide v3.10a, in '2.1.3.2 Dedicated
FIFO Mode with No Thresholding', it suggested that:

Device RxFIFO =
- Scatter/Gather DMA mode:
(4 * number of control endpoints + 6) + ((largest USB packet used / 4) +
1 for status information) + (2 * number of OUT endpoints) + 1 for Global NAK

on rockchip platforms:
(4 * 1 + 6) + ((1024 / 4) + 1) + (2 * 6) + 1 = 280

- Slave or Buffer DMA mode:
(5 * number of control endpoints + 8) + ((largest USB packet used / 4) +
1 for status information) + (2 * number of OUT endpoints) + 1 for Global NAK

on rockchip platforms:
(5 * 1 + 8) + ((1024 / 4) + 1) + (2 * 6) + 1 = 283

Device IN Endpoint TxFIFO =
The TxFIFO must equal at least one MaxPacketSize (MPS).

In addition to RxFIFO and TxFIFOs, refer to dwc2 databook v3.10a,
'Figure 2-13 Device Mode FIFO Address Mapping and AHB FIFO Access Mapping
(Dedicated FIFO)', it required that when the device is operating in non
Scatter Gather Internal DMA mode, the last locations of the SPRAM are used
to store the DMAADDR values for each Endpoint (1 location per endpoint).

When the device is operating in Scatter Gather mode, then the last locations
of the SPRAM store the Base Descriptor address, Current Descriptor address,
Current Buffer address, and status quadlet information for each endpoint
direction (4 locations per Endpoint). If an Endpoint is bidirectional , then
4 locations will be used for IN, and another 4 for OUT).

Considering that the total FIFO size of dwc2 otg is 0x3cc (972),
and we must reserve (4 * 13) = 52 locations for all Endpoints.
So reconfig dwc2 device fifo size as follows:

Device RxFIFO = 280
Device IN Endpoint TxFIFO
- FIFO #0 = (64 / 4) = 16 (Assuming this is used for EP0)
- FIFO #1 = (1024/4) = 256 (Assuming this is used for Isochronous)
- FIFO #2 = (512/4) = 128
- FIFO #3 = (512/4) = 128
- FIFO #4 = (256/4) = 64
- FIFO #5 = (128/4) = 32
- FIFO #6 = (64/4) = 16

After reconfig the dwc2 device fifo size, test mtp write on rockchip
platform (PC -> rockchip platform) on rk312x/rk3326/px30/rk3288 evb,
when mask the 'vfs_write' in f_mtp.c, the writing data rate can be
increased from 16MBps ~ 20MBps to 30MBps ~ 36MBps on different kinds
of rockchip evbs.

Change-Id: I52c64a279523c811f706e69e427b0a6e8c45683b
Signed-off-by: William Wu <[email protected]>
rkchrome pushed a commit that referenced this issue Jun 11, 2018
[ Upstream commit d754941 ]

If, for any reason, userland shuts down iscsi transport interfaces
before proper logouts - like when logging in to LUNs manually, without
logging out on server shutdown, or when automated scripts can't
umount/logout from logged LUNs - kernel will hang forever on its
sd_sync_cache() logic, after issuing the SYNCHRONIZE_CACHE cmd to all
still existent paths.

PID: 1 TASK: ffff8801a69b8000 CPU: 1 COMMAND: "systemd-shutdow"
 #0 [ffff8801a69c3a30] __schedule at ffffffff8183e9ee
 #1 [ffff8801a69c3a80] schedule at ffffffff8183f0d5
 #2 [ffff8801a69c3a98] schedule_timeout at ffffffff81842199
 #3 [ffff8801a69c3b40] io_schedule_timeout at ffffffff8183e604
 #4 [ffff8801a69c3b70] wait_for_completion_io_timeout at ffffffff8183fc6c
 #5 [ffff8801a69c3bd0] blk_execute_rq at ffffffff813cfe10
 #6 [ffff8801a69c3c88] scsi_execute at ffffffff815c3fc7
 #7 [ffff8801a69c3cc8] scsi_execute_req_flags at ffffffff815c60fe
 #8 [ffff8801a69c3d30] sd_sync_cache at ffffffff815d37d7
 #9 [ffff8801a69c3da8] sd_shutdown at ffffffff815d3c3c

This happens because iscsi_eh_cmd_timed_out(), the transport layer
timeout helper, would tell the queue timeout function (scsi_times_out)
to reset the request timer over and over, until the session state is
back to logged in state. Unfortunately, during server shutdown, this
might never happen again.

Other option would be "not to handle" the issue in the transport
layer. That would trigger the error handler logic, which would also need
the session state to be logged in again.

Best option, for such case, is to tell upper layers that the command was
handled during the transport layer error handler helper, marking it as
DID_NO_CONNECT, which will allow completion and inform about the
problem.

After the session was marked as ISCSI_STATE_FAILED, due to the first
timeout during the server shutdown phase, all subsequent cmds will fail
to be queued, allowing upper logic to fail faster.

Signed-off-by: Rafael David Tinoco <[email protected]>
Reviewed-by: Lee Duncan <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
rkchrome pushed a commit that referenced this issue Jul 19, 2018
[ Upstream commit 2c0aa08 ]

Scenario:
1. Port down and do fail over
2. Ap do rds_bind syscall

PID: 47039  TASK: ffff89887e2fe640  CPU: 47  COMMAND: "kworker/u:6"
 #0 [ffff898e35f159f0] machine_kexec at ffffffff8103abf9
 #1 [ffff898e35f15a60] crash_kexec at ffffffff810b96e3
 #2 [ffff898e35f15b30] oops_end at ffffffff8150f518
 #3 [ffff898e35f15b60] no_context at ffffffff8104854c
 #4 [ffff898e35f15ba0] __bad_area_nosemaphore at ffffffff81048675
 #5 [ffff898e35f15bf0] bad_area_nosemaphore at ffffffff810487d3
 #6 [ffff898e35f15c00] do_page_fault at ffffffff815120b8
 #7 [ffff898e35f15d10] page_fault at ffffffff8150ea95
    [exception RIP: unknown or invalid address]
    RIP: 0000000000000000  RSP: ffff898e35f15dc8  RFLAGS: 00010282
    RAX: 00000000fffffffe  RBX: ffff889b77f6fc00  RCX:ffffffff81c99d88
    RDX: 0000000000000000  RSI: ffff896019ee08e8  RDI:ffff889b77f6fc00
    RBP: ffff898e35f15df0   R8: ffff896019ee08c8  R9:0000000000000000
    R10: 0000000000000400  R11: 0000000000000000  R12:ffff896019ee08c0
    R13: ffff889b77f6fe68  R14: ffffffff81c99d80  R15: ffffffffa022a1e0
    ORIG_RAX: ffffffffffffffff  CS: 0010 SS: 0018
 #8 [ffff898e35f15dc8] cma_ndev_work_handler at ffffffffa022a228 [rdma_cm]
 #9 [ffff898e35f15df8] process_one_work at ffffffff8108a7c6
 #10 [ffff898e35f15e58] worker_thread at ffffffff8108bda0
 #11 [ffff898e35f15ee8] kthread at ffffffff81090fe6

PID: 45659  TASK: ffff880d313d2500  CPU: 31  COMMAND: "oracle_45659_ap"
 #0 [ffff881024ccfc98] __schedule at ffffffff8150bac4
 #1 [ffff881024ccfd40] schedule at ffffffff8150c2cf
 #2 [ffff881024ccfd50] __mutex_lock_slowpath at ffffffff8150cee7
 #3 [ffff881024ccfdc0] mutex_lock at ffffffff8150cdeb
 #4 [ffff881024ccfde0] rdma_destroy_id at ffffffffa022a027 [rdma_cm]
 #5 [ffff881024ccfe10] rds_ib_laddr_check at ffffffffa0357857 [rds_rdma]
 #6 [ffff881024ccfe50] rds_trans_get_preferred at ffffffffa0324c2a [rds]
 #7 [ffff881024ccfe80] rds_bind at ffffffffa031d690 [rds]
 #8 [ffff881024ccfeb0] sys_bind at ffffffff8142a670

PID: 45659                          PID: 47039
rds_ib_laddr_check
  /* create id_priv with a null event_handler */
  rdma_create_id
  rdma_bind_addr
    cma_acquire_dev
      /* add id_priv to cma_dev->id_list */
      cma_attach_to_dev
                                    cma_ndev_work_handler
                                      /* event_hanlder is null */
                                      id_priv->id.event_handler

Signed-off-by: Guanglei Li <[email protected]>
Signed-off-by: Honglei Wang <[email protected]>
Reviewed-by: Junxiao Bi <[email protected]>
Reviewed-by: Yanjun Zhu <[email protected]>
Reviewed-by: Leon Romanovsky <[email protected]>
Acked-by: Santosh Shilimkar <[email protected]>
Acked-by: Doug Ledford <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
rkchrome pushed a commit that referenced this issue Jul 19, 2018
[ Upstream commit 2bbea6e ]

when mounting an ISO filesystem sometimes (very rarely)
the system hangs because of a race condition between two tasks.

PID: 6766   TASK: ffff88007b2a6dd0  CPU: 0   COMMAND: "mount"
 #0 [ffff880078447ae0] __schedule at ffffffff8168d605
 #1 [ffff880078447b48] schedule_preempt_disabled at ffffffff8168ed49
 #2 [ffff880078447b58] __mutex_lock_slowpath at ffffffff8168c995
 #3 [ffff880078447bb8] mutex_lock at ffffffff8168bdef
 #4 [ffff880078447bd0] sr_block_ioctl at ffffffffa00b6818 [sr_mod]
 #5 [ffff880078447c10] blkdev_ioctl at ffffffff812fea50
 #6 [ffff880078447c70] ioctl_by_bdev at ffffffff8123a8b3
 #7 [ffff880078447c90] isofs_fill_super at ffffffffa04fb1e1 [isofs]
 #8 [ffff880078447da8] mount_bdev at ffffffff81202570
 #9 [ffff880078447e18] isofs_mount at ffffffffa04f9828 [isofs]
#10 [ffff880078447e28] mount_fs at ffffffff81202d09
#11 [ffff880078447e70] vfs_kern_mount at ffffffff8121ea8f
#12 [ffff880078447ea8] do_mount at ffffffff81220fee
#13 [ffff880078447f28] sys_mount at ffffffff812218d6
#14 [ffff880078447f80] system_call_fastpath at ffffffff81698c49
    RIP: 00007fd9ea914e9a  RSP: 00007ffd5d9bf648  RFLAGS: 00010246
    RAX: 00000000000000a5  RBX: ffffffff81698c49  RCX: 0000000000000010
    RDX: 00007fd9ec2bc210  RSI: 00007fd9ec2bc290  RDI: 00007fd9ec2bcf30
    RBP: 0000000000000000   R8: 0000000000000000   R9: 0000000000000010
    R10: 00000000c0ed0001  R11: 0000000000000206  R12: 00007fd9ec2bc040
    R13: 00007fd9eb6b2380  R14: 00007fd9ec2bc210  R15: 00007fd9ec2bcf30
    ORIG_RAX: 00000000000000a5  CS: 0033  SS: 002b

This task was trying to mount the cdrom.  It allocated and configured a
super_block struct and owned the write-lock for the super_block->s_umount
rwsem. While exclusively owning the s_umount lock, it called
sr_block_ioctl and waited to acquire the global sr_mutex lock.

PID: 6785   TASK: ffff880078720fb0  CPU: 0   COMMAND: "systemd-udevd"
 #0 [ffff880078417898] __schedule at ffffffff8168d605
 #1 [ffff880078417900] schedule at ffffffff8168dc59
 #2 [ffff880078417910] rwsem_down_read_failed at ffffffff8168f605
 #3 [ffff880078417980] call_rwsem_down_read_failed at ffffffff81328838
 #4 [ffff8800784179d0] down_read at ffffffff8168cde0
 #5 [ffff8800784179e8] get_super at ffffffff81201cc7
 #6 [ffff880078417a10] __invalidate_device at ffffffff8123a8de
 #7 [ffff880078417a40] flush_disk at ffffffff8123a94b
 #8 [ffff880078417a88] check_disk_change at ffffffff8123ab50
 #9 [ffff880078417ab0] cdrom_open at ffffffffa00a29e1 [cdrom]
#10 [ffff880078417b68] sr_block_open at ffffffffa00b6f9b [sr_mod]
#11 [ffff880078417b98] __blkdev_get at ffffffff8123ba86
#12 [ffff880078417bf0] blkdev_get at ffffffff8123bd65
#13 [ffff880078417c78] blkdev_open at ffffffff8123bf9b
#14 [ffff880078417c90] do_dentry_open at ffffffff811fc7f7
#15 [ffff880078417cd8] vfs_open at ffffffff811fc9cf
#16 [ffff880078417d00] do_last at ffffffff8120d53d
#17 [ffff880078417db0] path_openat at ffffffff8120e6b2
#18 [ffff880078417e48] do_filp_open at ffffffff8121082b
#19 [ffff880078417f18] do_sys_open at ffffffff811fdd33
#20 [ffff880078417f70] sys_open at ffffffff811fde4e
#21 [ffff880078417f80] system_call_fastpath at ffffffff81698c49
    RIP: 00007f29438b0c20  RSP: 00007ffc76624b78  RFLAGS: 00010246
    RAX: 0000000000000002  RBX: ffffffff81698c49  RCX: 0000000000000000
    RDX: 00007f2944a5fa70  RSI: 00000000000a0800  RDI: 00007f2944a5fa70
    RBP: 00007f2944a5f540   R8: 0000000000000000   R9: 0000000000000020
    R10: 00007f2943614c40  R11: 0000000000000246  R12: ffffffff811fde4e
    R13: ffff880078417f78  R14: 000000000000000c  R15: 00007f2944a4b010
    ORIG_RAX: 0000000000000002  CS: 0033  SS: 002b

This task tried to open the cdrom device, the sr_block_open function
acquired the global sr_mutex lock. The call to check_disk_change()
then saw an event flag indicating a possible media change and tried
to flush any cached data for the device.
As part of the flush, it tried to acquire the super_block->s_umount
lock associated with the cdrom device.
This was the same super_block as created and locked by the previous task.

The first task acquires the s_umount lock and then the sr_mutex_lock;
the second task acquires the sr_mutex_lock and then the s_umount lock.

This patch fixes the issue by moving check_disk_change() out of
cdrom_open() and let the caller take care of it.

Signed-off-by: Maurizio Lombardi <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
T-Firefly referenced this issue in FireflyTeam/kernel Aug 23, 2018
commit 888f229 upstream.

Recently I got a Caldigit TS3 Thunderbolt 3 dock, and noticed that upon
hotplugging my kernel would immediately crash due to igb:

[  680.825801] kernel BUG at drivers/pci/msi.c:352!
[  680.828388] invalid opcode: 0000 [#1] SMP
[  680.829194] Modules linked in: igb(O) thunderbolt i2c_algo_bit joydev vfat fat btusb btrtl btbcm btintel bluetooth ecdh_generic hp_wmi sparse_keymap rfkill wmi_bmof iTCO_wdt intel_rapl x86_pkg_temp_thermal coretemp crc32_pclmul snd_pcm rtsx_pci_ms mei_me snd_timer memstick snd pcspkr mei soundcore i2c_i801 tpm_tis psmouse shpchp wmi tpm_tis_core tpm video hp_wireless acpi_pad rtsx_pci_sdmmc mmc_core crc32c_intel serio_raw rtsx_pci mfd_core xhci_pci xhci_hcd i2c_hid i2c_core [last unloaded: igb]
[  680.831085] CPU: 1 PID: 78 Comm: kworker/u16:1 Tainted: G           O     4.15.0-rc3Lyude-Test+ #6
[  680.831596] Hardware name: HP HP ZBook Studio G4/826B, BIOS P71 Ver. 01.03 06/09/2017
[  680.832168] Workqueue: kacpi_hotplug acpi_hotplug_work_fn
[  680.832687] RIP: 0010:free_msi_irqs+0x180/0x1b0
[  680.833271] RSP: 0018:ffffc9000030fbf0 EFLAGS: 00010286
[  680.833761] RAX: ffff8803405f9c00 RBX: ffff88033e3d2e40 RCX: 000000000000002c
[  680.834278] RDX: 0000000000000000 RSI: 00000000000000ac RDI: ffff880340be2178
[  680.834832] RBP: 0000000000000000 R08: ffff880340be1ff0 R09: ffff8803405f9c00
[  680.835342] R10: 0000000000000000 R11: 0000000000000040 R12: ffff88033d63a298
[  680.835822] R13: ffff88033d63a000 R14: 0000000000000060 R15: ffff880341959000
[  680.836332] FS:  0000000000000000(0000) GS:ffff88034f440000(0000) knlGS:0000000000000000
[  680.836817] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  680.837360] CR2: 000055e64044afdf CR3: 0000000001c09002 CR4: 00000000003606e0
[  680.837954] Call Trace:
[  680.838853]  pci_disable_msix+0xce/0xf0
[  680.839616]  igb_reset_interrupt_capability+0x5d/0x60 [igb]
[  680.840278]  igb_remove+0x9d/0x110 [igb]
[  680.840764]  pci_device_remove+0x36/0xb0
[  680.841279]  device_release_driver_internal+0x157/0x220
[  680.841739]  pci_stop_bus_device+0x7d/0xa0
[  680.842255]  pci_stop_bus_device+0x2b/0xa0
[  680.842722]  pci_stop_bus_device+0x3d/0xa0
[  680.843189]  pci_stop_and_remove_bus_device+0xe/0x20
[  680.843627]  trim_stale_devices+0xf3/0x140
[  680.844086]  trim_stale_devices+0x94/0x140
[  680.844532]  trim_stale_devices+0xa6/0x140
[  680.845031]  ? get_slot_status+0x90/0xc0
[  680.845536]  acpiphp_check_bridge.part.5+0xfe/0x140
[  680.846021]  acpiphp_hotplug_notify+0x175/0x200
[  680.846581]  ? free_bridge+0x100/0x100
[  680.847113]  acpi_device_hotplug+0x8a/0x490
[  680.847535]  acpi_hotplug_work_fn+0x1a/0x30
[  680.848076]  process_one_work+0x182/0x3a0
[  680.848543]  worker_thread+0x2e/0x380
[  680.848963]  ? process_one_work+0x3a0/0x3a0
[  680.849373]  kthread+0x111/0x130
[  680.849776]  ? kthread_create_worker_on_cpu+0x50/0x50
[  680.850188]  ret_from_fork+0x1f/0x30
[  680.850601] Code: 43 14 85 c0 0f 84 d5 fe ff ff 31 ed eb 0f 83 c5 01 39 6b 14 0f 86 c5 fe ff ff 8b 7b 10 01 ef e8 b7 e4 d2 ff 48 83 78 70 00 74 e3 <0f> 0b 49 8d b5 a0 00 00 00 e8 62 6f d3 ff e9 c7 fe ff ff 48 8b
[  680.851497] RIP: free_msi_irqs+0x180/0x1b0 RSP: ffffc9000030fbf0

As it turns out, normally the freeing of IRQs that would fix this is called
inside of the scope of __igb_close(). However, since the device is
already gone by the point we try to unregister the netdevice from the
driver due to a hotplug we end up seeing that the netif isn't present
and thus, forget to free any of the device IRQs.

So: make sure that if we're in the process of dismantling the netdev, we
always allow __igb_close() to be called so that IRQs may be freed
normally. Additionally, only allow igb_close() to be called from
__igb_close() if it hasn't already been called for the given adapter.

Signed-off-by: Lyude Paul <[email protected]>
Fixes: 9474933 ("igb: close/suspend race in netif_device_detach")
Cc: Todd Fujinaka <[email protected]>
Cc: Stephen Hemminger <[email protected]>
Tested-by: Aaron Brown <[email protected]>
Signed-off-by: Jeff Kirsher <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
rkchrome pushed a commit that referenced this issue Sep 12, 2018
commit 89da619 upstream.

Kernel panic when with high memory pressure, calltrace looks like,

PID: 21439 TASK: ffff881be3afedd0 CPU: 16 COMMAND: "java"
 #0 [ffff881ec7ed7630] machine_kexec at ffffffff81059beb
 #1 [ffff881ec7ed7690] __crash_kexec at ffffffff81105942
 #2 [ffff881ec7ed7760] crash_kexec at ffffffff81105a30
 #3 [ffff881ec7ed7778] oops_end at ffffffff816902c8
 #4 [ffff881ec7ed77a0] no_context at ffffffff8167ff46
 #5 [ffff881ec7ed77f0] __bad_area_nosemaphore at ffffffff8167ffdc
 #6 [ffff881ec7ed7838] __node_set at ffffffff81680300
 #7 [ffff881ec7ed7860] __do_page_fault at ffffffff8169320f
 #8 [ffff881ec7ed78c0] do_page_fault at ffffffff816932b5
 #9 [ffff881ec7ed78f0] page_fault at ffffffff8168f4c8
    [exception RIP: _raw_spin_lock_irqsave+47]
    RIP: ffffffff8168edef RSP: ffff881ec7ed79a8 RFLAGS: 00010046
    RAX: 0000000000000246 RBX: ffffea0019740d00 RCX: ffff881ec7ed7fd8
    RDX: 0000000000020000 RSI: 0000000000000016 RDI: 0000000000000008
    RBP: ffff881ec7ed79a8 R8: 0000000000000246 R9: 000000000001a098
    R10: ffff88107ffda000 R11: 0000000000000000 R12: 0000000000000000
    R13: 0000000000000008 R14: ffff881ec7ed7a80 R15: ffff881be3afedd0
    ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018

It happens in the pagefault and results in double pagefault
during compacting pages when memory allocation fails.

Analysed the vmcore, the page leads to second pagefault is corrupted
with _mapcount=-256, but private=0.

It's caused by the race between migration and ballooning, and lock
missing in virtballoon_migratepage() of virtio_balloon driver.
This patch fix the bug.

Fixes: e225042 ("virtio_balloon: introduce migration primitives to balloon pages")
Cc: [email protected]
Signed-off-by: Jiang Biao <[email protected]>
Signed-off-by: Huang Chong <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
0lvin referenced this issue in free-z4u/roc-rk3328-cc-official Sep 15, 2018
commit 3e536e2 upstream.

There is a window for racing when printing directly to task->comm,
allowing other threads to see a non-terminated string. The vsnprintf
function fills the buffer, counts the truncated chars, then finally
writes the \0 at the end.

	creator                     other
	vsnprintf:
	  fill (not terminated)
	  count the rest            trace_sched_waking(p):
	  ...                         memcpy(comm, p->comm, TASK_COMM_LEN)
	  write \0

The consequences depend on how 'other' uses the string. In our case,
it was copied into the tracing system's saved cmdlines, a buffer of
adjacent TASK_COMM_LEN-byte buffers (note the 'n' where 0 should be):

	crash-arm64> x/1024s savedcmd->saved_cmdlines | grep 'evenk'
	0xffffffd5b3818640:     "irq/497-pwr_evenkworker/u16:12"

...and a strcpy out of there would cause stack corruption:

	[224761.522292] Kernel panic - not syncing: stack-protector:
	    Kernel stack is corrupted in: ffffff9bf9783c78

	crash-arm64> kbt | grep 'comm\|trace_print_context'
	FireflyTeam#6  0xffffff9bf9783c78 in trace_print_context+0x18c(+396)
	      comm (char [16]) =  "irq/497-pwr_even"

	crash-arm64> rd 0xffffffd4d0e17d14 8
	ffffffd4d0e17d14:  2f71726900000000 5f7277702d373934   ....irq/497-pwr_
	ffffffd4d0e17d24:  726f776b6e657665 3a3631752f72656b   evenkworker/u16:
	ffffffd4d0e17d34:  f9780248ff003231 cede60e0ffffff9b   12..H.x......`..
	ffffffd4d0e17d44:  cede60c8ffffffd4 00000fffffffffd4   .....`..........

The workaround in e09e286 (use strlcpy in __trace_find_cmdline) was
likely needed because of this same bug.

Solved by vsnprintf:ing to a local buffer, then using set_task_comm().
This way, there won't be a window where comm is not terminated.

Link: http://lkml.kernel.org/r/[email protected]

Cc: [email protected]
Fixes: bc0c38d ("ftrace: latency tracer infrastructure")
Reviewed-by: Steven Rostedt (VMware) <[email protected]>
Signed-off-by: Snild Dolkow <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
[backported to 3.18 / 4.4 by Snild]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
rkchrome pushed a commit that referenced this issue Sep 26, 2018
[ Upstream commit 2c0aa08 ]

Scenario:
1. Port down and do fail over
2. Ap do rds_bind syscall

PID: 47039  TASK: ffff89887e2fe640  CPU: 47  COMMAND: "kworker/u:6"
 #0 [ffff898e35f159f0] machine_kexec at ffffffff8103abf9
 #1 [ffff898e35f15a60] crash_kexec at ffffffff810b96e3
 #2 [ffff898e35f15b30] oops_end at ffffffff8150f518
 #3 [ffff898e35f15b60] no_context at ffffffff8104854c
 #4 [ffff898e35f15ba0] __bad_area_nosemaphore at ffffffff81048675
 #5 [ffff898e35f15bf0] bad_area_nosemaphore at ffffffff810487d3
 #6 [ffff898e35f15c00] do_page_fault at ffffffff815120b8
 #7 [ffff898e35f15d10] page_fault at ffffffff8150ea95
    [exception RIP: unknown or invalid address]
    RIP: 0000000000000000  RSP: ffff898e35f15dc8  RFLAGS: 00010282
    RAX: 00000000fffffffe  RBX: ffff889b77f6fc00  RCX:ffffffff81c99d88
    RDX: 0000000000000000  RSI: ffff896019ee08e8  RDI:ffff889b77f6fc00
    RBP: ffff898e35f15df0   R8: ffff896019ee08c8  R9:0000000000000000
    R10: 0000000000000400  R11: 0000000000000000  R12:ffff896019ee08c0
    R13: ffff889b77f6fe68  R14: ffffffff81c99d80  R15: ffffffffa022a1e0
    ORIG_RAX: ffffffffffffffff  CS: 0010 SS: 0018
 #8 [ffff898e35f15dc8] cma_ndev_work_handler at ffffffffa022a228 [rdma_cm]
 #9 [ffff898e35f15df8] process_one_work at ffffffff8108a7c6
 #10 [ffff898e35f15e58] worker_thread at ffffffff8108bda0
 #11 [ffff898e35f15ee8] kthread at ffffffff81090fe6

PID: 45659  TASK: ffff880d313d2500  CPU: 31  COMMAND: "oracle_45659_ap"
 #0 [ffff881024ccfc98] __schedule at ffffffff8150bac4
 #1 [ffff881024ccfd40] schedule at ffffffff8150c2cf
 #2 [ffff881024ccfd50] __mutex_lock_slowpath at ffffffff8150cee7
 #3 [ffff881024ccfdc0] mutex_lock at ffffffff8150cdeb
 #4 [ffff881024ccfde0] rdma_destroy_id at ffffffffa022a027 [rdma_cm]
 #5 [ffff881024ccfe10] rds_ib_laddr_check at ffffffffa0357857 [rds_rdma]
 #6 [ffff881024ccfe50] rds_trans_get_preferred at ffffffffa0324c2a [rds]
 #7 [ffff881024ccfe80] rds_bind at ffffffffa031d690 [rds]
 #8 [ffff881024ccfeb0] sys_bind at ffffffff8142a670

PID: 45659                          PID: 47039
rds_ib_laddr_check
  /* create id_priv with a null event_handler */
  rdma_create_id
  rdma_bind_addr
    cma_acquire_dev
      /* add id_priv to cma_dev->id_list */
      cma_attach_to_dev
                                    cma_ndev_work_handler
                                      /* event_hanlder is null */
                                      id_priv->id.event_handler

Signed-off-by: Guanglei Li <[email protected]>
Signed-off-by: Honglei Wang <[email protected]>
Reviewed-by: Junxiao Bi <[email protected]>
Reviewed-by: Yanjun Zhu <[email protected]>
Reviewed-by: Leon Romanovsky <[email protected]>
Acked-by: Santosh Shilimkar <[email protected]>
Acked-by: Doug Ledford <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
rkchrome pushed a commit that referenced this issue Sep 26, 2018
[ Upstream commit 2bbea6e ]

when mounting an ISO filesystem sometimes (very rarely)
the system hangs because of a race condition between two tasks.

PID: 6766   TASK: ffff88007b2a6dd0  CPU: 0   COMMAND: "mount"
 #0 [ffff880078447ae0] __schedule at ffffffff8168d605
 #1 [ffff880078447b48] schedule_preempt_disabled at ffffffff8168ed49
 #2 [ffff880078447b58] __mutex_lock_slowpath at ffffffff8168c995
 #3 [ffff880078447bb8] mutex_lock at ffffffff8168bdef
 #4 [ffff880078447bd0] sr_block_ioctl at ffffffffa00b6818 [sr_mod]
 #5 [ffff880078447c10] blkdev_ioctl at ffffffff812fea50
 #6 [ffff880078447c70] ioctl_by_bdev at ffffffff8123a8b3
 #7 [ffff880078447c90] isofs_fill_super at ffffffffa04fb1e1 [isofs]
 #8 [ffff880078447da8] mount_bdev at ffffffff81202570
 #9 [ffff880078447e18] isofs_mount at ffffffffa04f9828 [isofs]
#10 [ffff880078447e28] mount_fs at ffffffff81202d09
#11 [ffff880078447e70] vfs_kern_mount at ffffffff8121ea8f
#12 [ffff880078447ea8] do_mount at ffffffff81220fee
#13 [ffff880078447f28] sys_mount at ffffffff812218d6
#14 [ffff880078447f80] system_call_fastpath at ffffffff81698c49
    RIP: 00007fd9ea914e9a  RSP: 00007ffd5d9bf648  RFLAGS: 00010246
    RAX: 00000000000000a5  RBX: ffffffff81698c49  RCX: 0000000000000010
    RDX: 00007fd9ec2bc210  RSI: 00007fd9ec2bc290  RDI: 00007fd9ec2bcf30
    RBP: 0000000000000000   R8: 0000000000000000   R9: 0000000000000010
    R10: 00000000c0ed0001  R11: 0000000000000206  R12: 00007fd9ec2bc040
    R13: 00007fd9eb6b2380  R14: 00007fd9ec2bc210  R15: 00007fd9ec2bcf30
    ORIG_RAX: 00000000000000a5  CS: 0033  SS: 002b

This task was trying to mount the cdrom.  It allocated and configured a
super_block struct and owned the write-lock for the super_block->s_umount
rwsem. While exclusively owning the s_umount lock, it called
sr_block_ioctl and waited to acquire the global sr_mutex lock.

PID: 6785   TASK: ffff880078720fb0  CPU: 0   COMMAND: "systemd-udevd"
 #0 [ffff880078417898] __schedule at ffffffff8168d605
 #1 [ffff880078417900] schedule at ffffffff8168dc59
 #2 [ffff880078417910] rwsem_down_read_failed at ffffffff8168f605
 #3 [ffff880078417980] call_rwsem_down_read_failed at ffffffff81328838
 #4 [ffff8800784179d0] down_read at ffffffff8168cde0
 #5 [ffff8800784179e8] get_super at ffffffff81201cc7
 #6 [ffff880078417a10] __invalidate_device at ffffffff8123a8de
 #7 [ffff880078417a40] flush_disk at ffffffff8123a94b
 #8 [ffff880078417a88] check_disk_change at ffffffff8123ab50
 #9 [ffff880078417ab0] cdrom_open at ffffffffa00a29e1 [cdrom]
#10 [ffff880078417b68] sr_block_open at ffffffffa00b6f9b [sr_mod]
#11 [ffff880078417b98] __blkdev_get at ffffffff8123ba86
#12 [ffff880078417bf0] blkdev_get at ffffffff8123bd65
#13 [ffff880078417c78] blkdev_open at ffffffff8123bf9b
#14 [ffff880078417c90] do_dentry_open at ffffffff811fc7f7
#15 [ffff880078417cd8] vfs_open at ffffffff811fc9cf
#16 [ffff880078417d00] do_last at ffffffff8120d53d
#17 [ffff880078417db0] path_openat at ffffffff8120e6b2
#18 [ffff880078417e48] do_filp_open at ffffffff8121082b
#19 [ffff880078417f18] do_sys_open at ffffffff811fdd33
#20 [ffff880078417f70] sys_open at ffffffff811fde4e
#21 [ffff880078417f80] system_call_fastpath at ffffffff81698c49
    RIP: 00007f29438b0c20  RSP: 00007ffc76624b78  RFLAGS: 00010246
    RAX: 0000000000000002  RBX: ffffffff81698c49  RCX: 0000000000000000
    RDX: 00007f2944a5fa70  RSI: 00000000000a0800  RDI: 00007f2944a5fa70
    RBP: 00007f2944a5f540   R8: 0000000000000000   R9: 0000000000000020
    R10: 00007f2943614c40  R11: 0000000000000246  R12: ffffffff811fde4e
    R13: ffff880078417f78  R14: 000000000000000c  R15: 00007f2944a4b010
    ORIG_RAX: 0000000000000002  CS: 0033  SS: 002b

This task tried to open the cdrom device, the sr_block_open function
acquired the global sr_mutex lock. The call to check_disk_change()
then saw an event flag indicating a possible media change and tried
to flush any cached data for the device.
As part of the flush, it tried to acquire the super_block->s_umount
lock associated with the cdrom device.
This was the same super_block as created and locked by the previous task.

The first task acquires the s_umount lock and then the sr_mutex_lock;
the second task acquires the sr_mutex_lock and then the s_umount lock.

This patch fixes the issue by moving check_disk_change() out of
cdrom_open() and let the caller take care of it.

Signed-off-by: Maurizio Lombardi <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
rkchrome pushed a commit that referenced this issue Sep 26, 2018
commit 89da619 upstream.

Kernel panic when with high memory pressure, calltrace looks like,

PID: 21439 TASK: ffff881be3afedd0 CPU: 16 COMMAND: "java"
 #0 [ffff881ec7ed7630] machine_kexec at ffffffff81059beb
 #1 [ffff881ec7ed7690] __crash_kexec at ffffffff81105942
 #2 [ffff881ec7ed7760] crash_kexec at ffffffff81105a30
 #3 [ffff881ec7ed7778] oops_end at ffffffff816902c8
 #4 [ffff881ec7ed77a0] no_context at ffffffff8167ff46
 #5 [ffff881ec7ed77f0] __bad_area_nosemaphore at ffffffff8167ffdc
 #6 [ffff881ec7ed7838] __node_set at ffffffff81680300
 #7 [ffff881ec7ed7860] __do_page_fault at ffffffff8169320f
 #8 [ffff881ec7ed78c0] do_page_fault at ffffffff816932b5
 #9 [ffff881ec7ed78f0] page_fault at ffffffff8168f4c8
    [exception RIP: _raw_spin_lock_irqsave+47]
    RIP: ffffffff8168edef RSP: ffff881ec7ed79a8 RFLAGS: 00010046
    RAX: 0000000000000246 RBX: ffffea0019740d00 RCX: ffff881ec7ed7fd8
    RDX: 0000000000020000 RSI: 0000000000000016 RDI: 0000000000000008
    RBP: ffff881ec7ed79a8 R8: 0000000000000246 R9: 000000000001a098
    R10: ffff88107ffda000 R11: 0000000000000000 R12: 0000000000000000
    R13: 0000000000000008 R14: ffff881ec7ed7a80 R15: ffff881be3afedd0
    ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018

It happens in the pagefault and results in double pagefault
during compacting pages when memory allocation fails.

Analysed the vmcore, the page leads to second pagefault is corrupted
with _mapcount=-256, but private=0.

It's caused by the race between migration and ballooning, and lock
missing in virtballoon_migratepage() of virtio_balloon driver.
This patch fix the bug.

Fixes: e225042 ("virtio_balloon: introduce migration primitives to balloon pages")
Cc: [email protected]
Signed-off-by: Jiang Biao <[email protected]>
Signed-off-by: Huang Chong <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
0lvin referenced this issue in free-z4u/roc-rk3328-cc-official Dec 25, 2018
If the lower or upper directory of an overlayfs mount belong to a btrfs
file system and we fsync the file through the overlayfs' merged directory
we ended up accessing an inode that didn't belong to btrfs as if it were
a btrfs inode at btrfs_sync_file() resulting in a crash like the following:

[ 7782.588845] BUG: unable to handle kernel NULL pointer dereference at 0000000000000544
[ 7782.590624] IP: [<ffffffffa030b7ab>] btrfs_sync_file+0x11b/0x3e9 [btrfs]
[ 7782.591931] PGD 4d954067 PUD 1e878067 PMD 0
[ 7782.592016] Oops: 0002 [FireflyTeam#6] PREEMPT SMP DEBUG_PAGEALLOC
[ 7782.592016] Modules linked in: btrfs overlay ppdev crc32c_generic evdev xor raid6_pq psmouse pcspkr sg serio_raw acpi_cpufreq parport_pc parport tpm_tis i2c_piix4 tpm i2c_core processor button loop autofs4 ext4 crc16 mbcache jbd2 sr_mod cdrom sd_mod ata_generic virtio_scsi ata_piix virtio_pci libata virtio_ring virtio scsi_mod e1000 floppy [last unloaded: btrfs]
[ 7782.592016] CPU: 10 PID: 16437 Comm: xfs_io Tainted: G      D         4.5.0-rc6-btrfs-next-26+ FireflyTeam#1
[ 7782.592016] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014
[ 7782.592016] task: ffff88001b8d40c0 ti: ffff880137488000 task.ti: ffff880137488000
[ 7782.592016] RIP: 0010:[<ffffffffa030b7ab>]  [<ffffffffa030b7ab>] btrfs_sync_file+0x11b/0x3e9 [btrfs]
[ 7782.592016] RSP: 0018:ffff88013748be40  EFLAGS: 00010286
[ 7782.592016] RAX: 0000000080000000 RBX: ffff880133b30c88 RCX: 0000000000000001
[ 7782.592016] RDX: 0000000000000001 RSI: ffffffff8148fec0 RDI: 00000000ffffffff
[ 7782.592016] RBP: ffff88013748bec0 R08: 0000000000000001 R09: 0000000000000000
[ 7782.624248] R10: ffff88013748be40 R11: 0000000000000246 R12: 0000000000000000
[ 7782.624248] R13: 0000000000000000 R14: 00000000009305a0 R15: ffff880015e3be40
[ 7782.624248] FS:  00007fa83b9cb700(0000) GS:ffff88023ed40000(0000) knlGS:0000000000000000
[ 7782.624248] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 7782.624248] CR2: 0000000000000544 CR3: 00000001fa652000 CR4: 00000000000006e0
[ 7782.624248] Stack:
[ 7782.624248]  ffffffff8108b5cc ffff88013748bec0 0000000000000246 ffff8800b005ded0
[ 7782.624248]  ffff880133b30d60 8000000000000000 7fffffffffffffff 0000000000000246
[ 7782.624248]  0000000000000246 ffffffff81074f9b ffffffff8104357c ffff880015e3be40
[ 7782.624248] Call Trace:
[ 7782.624248]  [<ffffffff8108b5cc>] ? arch_local_irq_save+0x9/0xc
[ 7782.624248]  [<ffffffff81074f9b>] ? ___might_sleep+0xce/0x217
[ 7782.624248]  [<ffffffff8104357c>] ? __do_page_fault+0x3c0/0x43a
[ 7782.624248]  [<ffffffff811a2351>] vfs_fsync_range+0x8c/0x9e
[ 7782.624248]  [<ffffffff811a237f>] vfs_fsync+0x1c/0x1e
[ 7782.624248]  [<ffffffff811a24d6>] do_fsync+0x31/0x4a
[ 7782.624248]  [<ffffffff811a2700>] SyS_fsync+0x10/0x14
[ 7782.624248]  [<ffffffff81493617>] entry_SYSCALL_64_fastpath+0x12/0x6b
[ 7782.624248] Code: 85 c0 0f 85 e2 02 00 00 48 8b 45 b0 31 f6 4c 29 e8 48 ff c0 48 89 45 a8 48 8d 83 d8 00 00 00 48 89 c7 48 89 45 a0 e8 fc 43 18 e1 <f0> 41 ff 84 24 44 05 00 00 48 8b 83 58 ff ff ff 48 c1 e8 07 83
[ 7782.624248] RIP  [<ffffffffa030b7ab>] btrfs_sync_file+0x11b/0x3e9 [btrfs]
[ 7782.624248]  RSP <ffff88013748be40>
[ 7782.624248] CR2: 0000000000000544
[ 7782.661994] ---[ end trace 721e14960eb939bc ]---

This started happening since commit 4bacc9c (overlayfs: Make f_path
always point to the overlay and f_inode to the underlay) and even though
after this change we could still access the btrfs inode through
struct file->f_mapping->host or struct file->f_inode, we would end up
resulting in more similar issues later on at check_parent_dirs_for_sync()
because the dentry we got (from struct file->f_path.dentry) was from
overlayfs and not from btrfs, that is, we had no way of getting the dentry
that belonged to btrfs (we always got the dentry that belonged to
overlayfs).

The new patch from Miklos Szeredi, titled "vfs: add file_dentry()" and
recently submitted to linux-fsdevel, adds a file_dentry() API that allows
us to get the btrfs dentry from the input file and therefore being able
to fsync when the upper and lower directories belong to btrfs filesystems.

This issue has been reported several times by users in the mailing list
and bugzilla. A test case for xfstests is being submitted as well.

Fixes: 4bacc9c ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay")
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=101951
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=109791
Signed-off-by: Filipe Manana <[email protected]>
Signed-off-by: Chris Mason <[email protected]>
Cc: [email protected]
0lvin referenced this issue in free-z4u/roc-rk3328-cc-official Dec 25, 2018
commit e2c8b87 moved modeset locking inside resume/suspend
functions, but missed a code path only executed on lid close/open
on older hardware. The result was a deadlock when closing and
opening the lid without suspending on such hardware:

 =============================================
 [ INFO: possible recursive locking detected ]
 4.6.0-rc1 #385 Not tainted
 ---------------------------------------------
 kworker/0:3/88 is trying to acquire lock:
  (&dev->mode_config.mutex){+.+.+.}, at: [<ffffffffa063e6a4>] intel_display_resume+0x4a/0x12f [i915]

 but task is already holding lock:
  (&dev->mode_config.mutex){+.+.+.}, at: [<ffffffffa02d0d4f>] drm_modeset_lock_all+0x3e/0xa6 [drm]

 other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(&dev->mode_config.mutex);
   lock(&dev->mode_config.mutex);

  *** DEADLOCK ***

  May be due to missing lock nesting notation

 7 locks held by kworker/0:3/88:
  #0:  ("kacpi_notify"){++++.+}, at: [<ffffffff81068dfc>] process_one_work+0x14a/0x50b
  FireflyTeam#1:  ((&dpc->work)FireflyTeam#2){+.+.+.}, at: [<ffffffff81068dfc>] process_one_work+0x14a/0x50b
  FireflyTeam#2:  ((acpi_lid_notifier).rwsem){++++.+}, at: [<ffffffff8106f874>] __blocking_notifier_call_chain+0x34/0x65
  FireflyTeam#3:  (&dev_priv->modeset_restore_lock){+.+.+.}, at: [<ffffffffa0664cf6>] intel_lid_notify+0x3c/0xd9 [i915]
  FireflyTeam#4:  (&dev->mode_config.mutex){+.+.+.}, at: [<ffffffffa02d0d4f>] drm_modeset_lock_all+0x3e/0xa6 [drm]
  FireflyTeam#5:  (crtc_ww_class_acquire){+.+.+.}, at: [<ffffffffa02d0d59>] drm_modeset_lock_all+0x48/0xa6 [drm]
  FireflyTeam#6:  (crtc_ww_class_mutex){+.+.+.}, at: [<ffffffffa02d0b2a>] modeset_lock+0x13c/0x1cd [drm]

 stack backtrace:
 CPU: 0 PID: 88 Comm: kworker/0:3 Not tainted 4.6.0-rc1 #385
 Hardware name: LENOVO 2776LEG/2776LEG, BIOS 6EET55WW (3.15 ) 12/19/2011
 Workqueue: kacpi_notify acpi_os_execute_deferred
  0000000000000000 ffff88022fd5f990 ffffffff8124af06 ffffffff825b39c0
  ffffffff825b39c0 ffff88022fd5fa60 ffffffff8108f547 ffff88022fd5fa70
  000000008108e817 ffff880230236cc0 0000000000000000 ffffffff825b39c0
 Call Trace:
  [<ffffffff8124af06>] dump_stack+0x67/0x90
  [<ffffffff8108f547>] __lock_acquire+0xdb5/0xf71
  [<ffffffff8108bd2c>] ? look_up_lock_class+0xbe/0x10a
  [<ffffffff8108fae2>] lock_acquire+0x137/0x1cb
  [<ffffffff8108fae2>] ? lock_acquire+0x137/0x1cb
  [<ffffffffa063e6a4>] ? intel_display_resume+0x4a/0x12f [i915]
  [<ffffffff8148202f>] mutex_lock_nested+0x7e/0x3a4
  [<ffffffffa063e6a4>] ? intel_display_resume+0x4a/0x12f [i915]
  [<ffffffffa063e6a4>] ? intel_display_resume+0x4a/0x12f [i915]
  [<ffffffffa02d0b2a>] ? modeset_lock+0x13c/0x1cd [drm]
  [<ffffffffa063e6a4>] intel_display_resume+0x4a/0x12f [i915]
  [<ffffffffa063e6a4>] ? intel_display_resume+0x4a/0x12f [i915]
  [<ffffffffa02d0b2a>] ? modeset_lock+0x13c/0x1cd [drm]
  [<ffffffffa02d0b2a>] ? modeset_lock+0x13c/0x1cd [drm]
  [<ffffffffa02d0bf7>] ? drm_modeset_lock+0x17/0x24 [drm]
  [<ffffffffa02d0c8b>] ? drm_modeset_lock_all_ctx+0x87/0xa1 [drm]
  [<ffffffffa0664d6a>] intel_lid_notify+0xb0/0xd9 [i915]
  [<ffffffff8106f4c6>] notifier_call_chain+0x4a/0x6c
  [<ffffffff8106f88d>] __blocking_notifier_call_chain+0x4d/0x65
  [<ffffffff8106f8b9>] blocking_notifier_call_chain+0x14/0x16
  [<ffffffffa0011215>] acpi_lid_send_state+0x83/0xad [button]
  [<ffffffffa00112a6>] acpi_button_notify+0x41/0x132 [button]
  [<ffffffff812b07df>] acpi_device_notify+0x19/0x1b
  [<ffffffff812c8570>] acpi_ev_notify_dispatch+0x49/0x64
  [<ffffffff812ab9fb>] acpi_os_execute_deferred+0x14/0x20
  [<ffffffff81068f17>] process_one_work+0x265/0x50b
  [<ffffffff810696f5>] worker_thread+0x1fc/0x2dd
  [<ffffffff810694f9>] ? rescuer_thread+0x309/0x309
  [<ffffffff810694f9>] ? rescuer_thread+0x309/0x309
  [<ffffffff8106e2d6>] kthread+0xe0/0xe8
  [<ffffffff8107bc47>] ? local_clock+0x19/0x22
  [<ffffffff81484f42>] ret_from_fork+0x22/0x40
  [<ffffffff8106e1f6>] ? kthread_create_on_node+0x1b5/0x1b5

Fixes: e2c8b87 ("drm/i915: Use atomic helpers for suspend, v2.")
Cc: Maarten Lankhorst <[email protected]>
Signed-off-by: Bjørn Mork <[email protected]>
Signed-off-by: Maarten Lankhorst <[email protected]>
Link: http://patchwork.freedesktop.org/patch/msgid/[email protected]
(cherry picked from commit 9f54d4b)
Signed-off-by: Jani Nikula <[email protected]>
0lvin referenced this issue in free-z4u/roc-rk3328-cc-official Dec 25, 2018
The bug in a workqueue leads to a stalled IO request in MQ ctx->rq_list
with the following backtrace:

[  601.347452] INFO: task kworker/u129:5:1636 blocked for more than 120 seconds.
[  601.347574]       Tainted: G           O    4.4.5-1-storage+ FireflyTeam#6
[  601.347651] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[  601.348142] kworker/u129:5  D ffff880803077988     0  1636      2 0x00000000
[  601.348519] Workqueue: ibnbd_server_fileio_wq ibnbd_dev_file_submit_io_worker [ibnbd_server]
[  601.348999]  ffff880803077988 ffff88080466b900 ffff8808033f9c80 ffff880803078000
[  601.349662]  ffff880807c95000 7fffffffffffffff ffffffff815b0920 ffff880803077ad0
[  601.350333]  ffff8808030779a0 ffffffff815b01d5 0000000000000000 ffff880803077a38
[  601.350965] Call Trace:
[  601.351203]  [<ffffffff815b0920>] ? bit_wait+0x60/0x60
[  601.351444]  [<ffffffff815b01d5>] schedule+0x35/0x80
[  601.351709]  [<ffffffff815b2dd2>] schedule_timeout+0x192/0x230
[  601.351958]  [<ffffffff812d43f7>] ? blk_flush_plug_list+0xc7/0x220
[  601.352208]  [<ffffffff810bd737>] ? ktime_get+0x37/0xa0
[  601.352446]  [<ffffffff815b0920>] ? bit_wait+0x60/0x60
[  601.352688]  [<ffffffff815af784>] io_schedule_timeout+0xa4/0x110
[  601.352951]  [<ffffffff815b3a4e>] ? _raw_spin_unlock_irqrestore+0xe/0x10
[  601.353196]  [<ffffffff815b093b>] bit_wait_io+0x1b/0x70
[  601.353440]  [<ffffffff815b056d>] __wait_on_bit+0x5d/0x90
[  601.353689]  [<ffffffff81127bd0>] wait_on_page_bit+0xc0/0xd0
[  601.353958]  [<ffffffff81096db0>] ? autoremove_wake_function+0x40/0x40
[  601.354200]  [<ffffffff81127cc4>] __filemap_fdatawait_range+0xe4/0x140
[  601.354441]  [<ffffffff81127d34>] filemap_fdatawait_range+0x14/0x30
[  601.354688]  [<ffffffff81129a9f>] filemap_write_and_wait_range+0x3f/0x70
[  601.354932]  [<ffffffff811ced3b>] blkdev_fsync+0x1b/0x50
[  601.355193]  [<ffffffff811c82d9>] vfs_fsync_range+0x49/0xa0
[  601.355432]  [<ffffffff811cf45a>] blkdev_write_iter+0xca/0x100
[  601.355679]  [<ffffffff81197b1a>] __vfs_write+0xaa/0xe0
[  601.355925]  [<ffffffff81198379>] vfs_write+0xa9/0x1a0
[  601.356164]  [<ffffffff811c59d8>] kernel_write+0x38/0x50

The underlying device is a null_blk, with default parameters:

  queue_mode    = MQ
  submit_queues = 1

Verification that nullb0 has something inflight:

root@pserver8:~# cat /sys/block/nullb0/inflight
       0        1
root@pserver8:~# find /sys/block/nullb0/mq/0/cpu* -name rq_list -print -exec cat {} \;
...
/sys/block/nullb0/mq/0/cpu2/rq_list
CTX pending:
        ffff8838038e2400
...

During debug it became clear that stalled request is always inserted in
the rq_list from the following path:

   save_stack_trace_tsk + 34
   blk_mq_insert_requests + 231
   blk_mq_flush_plug_list + 281
   blk_flush_plug_list + 199
   wait_on_page_bit + 192
   __filemap_fdatawait_range + 228
   filemap_fdatawait_range + 20
   filemap_write_and_wait_range + 63
   blkdev_fsync + 27
   vfs_fsync_range + 73
   blkdev_write_iter + 202
   __vfs_write + 170
   vfs_write + 169
   kernel_write + 56

So blk_flush_plug_list() was called with from_schedule == true.

If from_schedule is true, that means that finally blk_mq_insert_requests()
offloads execution of __blk_mq_run_hw_queue() and uses kblockd workqueue,
i.e. it calls kblockd_schedule_delayed_work_on().

That means, that we race with another CPU, which is about to execute
__blk_mq_run_hw_queue() work.

Further debugging shows the following traces from different CPUs:

  CPU#0                                  CPU#1
  ----------------------------------     -------------------------------
  reqeust A inserted
  STORE hctx->ctx_map[0] bit marked
  kblockd_schedule...() returns 1
  <schedule to kblockd workqueue>
                                         request B inserted
                                         STORE hctx->ctx_map[1] bit marked
                                         kblockd_schedule...() returns 0
  *** WORK PENDING bit is cleared ***
  flush_busy_ctxs() is executed, but
  bit 1, set by CPU#1, is not observed

As a result request B pended forever.

This behaviour can be explained by speculative LOAD of hctx->ctx_map on
CPU#0, which is reordered with clear of PENDING bit and executed _before_
actual STORE of bit 1 on CPU#1.

The proper fix is an explicit full barrier <mfence>, which guarantees
that clear of PENDING bit is to be executed before all possible
speculative LOADS or STORES inside actual work function.

Signed-off-by: Roman Pen <[email protected]>
Cc: Gioh Kim <[email protected]>
Cc: Michael Wang <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Tejun Heo <[email protected]>
0lvin referenced this issue in free-z4u/roc-rk3328-cc-official Dec 25, 2018
Assume memory47 is the last online block left in node1.  This will hang:

  # echo offline > /sys/devices/system/node/node1/memory47/state

After a couple of minutes, the following pops up in dmesg:

  INFO: task bash:957 blocked for more than 120 seconds.
         Not tainted 4.6.0-rc6+ FireflyTeam#6
  "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  bash            D ffff8800b7adbaf8     0   957    951 0x00000000
  Call Trace:
    schedule+0x35/0x80
    schedule_timeout+0x1ac/0x270
    wait_for_completion+0xe1/0x120
    kthread_stop+0x4f/0x110
    kcompactd_stop+0x26/0x40
    __offline_pages.constprop.28+0x7e6/0x840
    offline_pages+0x11/0x20
    memory_block_action+0x73/0x1d0
    memory_subsys_offline+0x47/0x60
    device_offline+0x86/0xb0
    store_mem_state+0xda/0xf0
    dev_attr_store+0x18/0x30
    sysfs_kf_write+0x37/0x40
    kernfs_fop_write+0x11d/0x170
    __vfs_write+0x37/0x120
    vfs_write+0xa9/0x1a0
    SyS_write+0x55/0xc0
    entry_SYSCALL_64_fastpath+0x1a/0xa4

kcompactd is waiting for kcompactd_max_order > 0 when it's woken up to
actually exit.  Check kthread_should_stop() to break out of the wait.

Fixes: 698b1b3 ("mm, compaction: introduce kcompactd").
Reported-by: Reza Arbab <[email protected]>
Tested-by: Reza Arbab <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: "Kirill A. Shutemov" <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Hugh Dickins <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
0lvin referenced this issue in free-z4u/roc-rk3328-cc-official Jan 7, 2019
commit e2c8b87 moved modeset locking inside resume/suspend
functions, but missed a code path only executed on lid close/open
on older hardware. The result was a deadlock when closing and
opening the lid without suspending on such hardware:

 =============================================
 [ INFO: possible recursive locking detected ]
 4.6.0-rc1 #385 Not tainted
 ---------------------------------------------
 kworker/0:3/88 is trying to acquire lock:
  (&dev->mode_config.mutex){+.+.+.}, at: [<ffffffffa063e6a4>] intel_display_resume+0x4a/0x12f [i915]

 but task is already holding lock:
  (&dev->mode_config.mutex){+.+.+.}, at: [<ffffffffa02d0d4f>] drm_modeset_lock_all+0x3e/0xa6 [drm]

 other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(&dev->mode_config.mutex);
   lock(&dev->mode_config.mutex);

  *** DEADLOCK ***

  May be due to missing lock nesting notation

 7 locks held by kworker/0:3/88:
  #0:  ("kacpi_notify"){++++.+}, at: [<ffffffff81068dfc>] process_one_work+0x14a/0x50b
  FireflyTeam#1:  ((&dpc->work)FireflyTeam#2){+.+.+.}, at: [<ffffffff81068dfc>] process_one_work+0x14a/0x50b
  FireflyTeam#2:  ((acpi_lid_notifier).rwsem){++++.+}, at: [<ffffffff8106f874>] __blocking_notifier_call_chain+0x34/0x65
  FireflyTeam#3:  (&dev_priv->modeset_restore_lock){+.+.+.}, at: [<ffffffffa0664cf6>] intel_lid_notify+0x3c/0xd9 [i915]
  FireflyTeam#4:  (&dev->mode_config.mutex){+.+.+.}, at: [<ffffffffa02d0d4f>] drm_modeset_lock_all+0x3e/0xa6 [drm]
  FireflyTeam#5:  (crtc_ww_class_acquire){+.+.+.}, at: [<ffffffffa02d0d59>] drm_modeset_lock_all+0x48/0xa6 [drm]
  FireflyTeam#6:  (crtc_ww_class_mutex){+.+.+.}, at: [<ffffffffa02d0b2a>] modeset_lock+0x13c/0x1cd [drm]

 stack backtrace:
 CPU: 0 PID: 88 Comm: kworker/0:3 Not tainted 4.6.0-rc1 #385
 Hardware name: LENOVO 2776LEG/2776LEG, BIOS 6EET55WW (3.15 ) 12/19/2011
 Workqueue: kacpi_notify acpi_os_execute_deferred
  0000000000000000 ffff88022fd5f990 ffffffff8124af06 ffffffff825b39c0
  ffffffff825b39c0 ffff88022fd5fa60 ffffffff8108f547 ffff88022fd5fa70
  000000008108e817 ffff880230236cc0 0000000000000000 ffffffff825b39c0
 Call Trace:
  [<ffffffff8124af06>] dump_stack+0x67/0x90
  [<ffffffff8108f547>] __lock_acquire+0xdb5/0xf71
  [<ffffffff8108bd2c>] ? look_up_lock_class+0xbe/0x10a
  [<ffffffff8108fae2>] lock_acquire+0x137/0x1cb
  [<ffffffff8108fae2>] ? lock_acquire+0x137/0x1cb
  [<ffffffffa063e6a4>] ? intel_display_resume+0x4a/0x12f [i915]
  [<ffffffff8148202f>] mutex_lock_nested+0x7e/0x3a4
  [<ffffffffa063e6a4>] ? intel_display_resume+0x4a/0x12f [i915]
  [<ffffffffa063e6a4>] ? intel_display_resume+0x4a/0x12f [i915]
  [<ffffffffa02d0b2a>] ? modeset_lock+0x13c/0x1cd [drm]
  [<ffffffffa063e6a4>] intel_display_resume+0x4a/0x12f [i915]
  [<ffffffffa063e6a4>] ? intel_display_resume+0x4a/0x12f [i915]
  [<ffffffffa02d0b2a>] ? modeset_lock+0x13c/0x1cd [drm]
  [<ffffffffa02d0b2a>] ? modeset_lock+0x13c/0x1cd [drm]
  [<ffffffffa02d0bf7>] ? drm_modeset_lock+0x17/0x24 [drm]
  [<ffffffffa02d0c8b>] ? drm_modeset_lock_all_ctx+0x87/0xa1 [drm]
  [<ffffffffa0664d6a>] intel_lid_notify+0xb0/0xd9 [i915]
  [<ffffffff8106f4c6>] notifier_call_chain+0x4a/0x6c
  [<ffffffff8106f88d>] __blocking_notifier_call_chain+0x4d/0x65
  [<ffffffff8106f8b9>] blocking_notifier_call_chain+0x14/0x16
  [<ffffffffa0011215>] acpi_lid_send_state+0x83/0xad [button]
  [<ffffffffa00112a6>] acpi_button_notify+0x41/0x132 [button]
  [<ffffffff812b07df>] acpi_device_notify+0x19/0x1b
  [<ffffffff812c8570>] acpi_ev_notify_dispatch+0x49/0x64
  [<ffffffff812ab9fb>] acpi_os_execute_deferred+0x14/0x20
  [<ffffffff81068f17>] process_one_work+0x265/0x50b
  [<ffffffff810696f5>] worker_thread+0x1fc/0x2dd
  [<ffffffff810694f9>] ? rescuer_thread+0x309/0x309
  [<ffffffff810694f9>] ? rescuer_thread+0x309/0x309
  [<ffffffff8106e2d6>] kthread+0xe0/0xe8
  [<ffffffff8107bc47>] ? local_clock+0x19/0x22
  [<ffffffff81484f42>] ret_from_fork+0x22/0x40
  [<ffffffff8106e1f6>] ? kthread_create_on_node+0x1b5/0x1b5

Fixes: e2c8b87 ("drm/i915: Use atomic helpers for suspend, v2.")
Cc: Maarten Lankhorst <[email protected]>
Signed-off-by: Bjørn Mork <[email protected]>
Signed-off-by: Maarten Lankhorst <[email protected]>
Link: http://patchwork.freedesktop.org/patch/msgid/[email protected]
0lvin referenced this issue in free-z4u/roc-rk3328-cc-official Jan 27, 2019
Currently, smp_processor_id() is used to fetch the current CPU in
cpu_idle_loop(). Every time the idle thread runs, it fetches the
current CPU using smp_processor_id().

Since the idle thread is per CPU, the current CPU is constant, so we
can lift the load out of the loop, saving execution cycles/time in the
loop.

x86-64:

Before patch (execution in loop):
	148:    0f ae e8                lfence
	14b:    65 8b 04 25 00 00 00 00 mov %gs:0x0,%eax
	152:    00
	153:    89 c0                   mov %eax,%eax
	155:    49 0f a3 04 24          bt %rax,(%r12)

After patch (execution in loop):
	150:    0f ae e8                lfence
	153:    4d 0f a3 34 24          bt %r14,(%r12)

ARM64:

Before patch (execution in loop):
	168:    d5033d9f        dsb     ld
	16c:    b9405661        ldr     w1,[x19,rockchip-linux#84]
	170:    1100fc20        add     w0,w1,#0x3f
	174:    6b1f003f        cmp     w1,wzr
	178:    1a81b000        csel    w0,w0,w1,lt
	17c:    130c7000        asr     w0,w0,FireflyTeam#6
	180:    937d7c00        sbfiz   x0,x0,FireflyTeam#3,rockchip-linux#32
	184:    f8606aa0        ldr     x0,[x21,x0]
	188:    9ac12401        lsr     x1,x0,x1
	18c:    36000e61        tbz     w1,#0,358

After patch (execution in loop):
	1a8:    d50339df        dsb     ld
	1ac:    f8776ac0        ldr     x0,[x22,x23]
	ab0:    ea18001f        tst     x0,x24
	1b4:    54000ea0        b.eq    388

Further observance on ARM64 for 4 seconds shows that cpu_idle_loop is
called 8672 times. Shifting the code will save instructions executed
in loop and eventually time as well.

Signed-off-by: Gaurav Jindal <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Sanjeev Yadav <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
0lvin referenced this issue in free-z4u/roc-rk3328-cc-official Feb 2, 2019
Don't free the object until the file handle has been closed.  Fixes
use-after-free bug which occurs when I disconnect my DVB-S received
while VDR is running.

This is a crash dump of such a use-after-free:

    general protection fault: 0000 [FireflyTeam#1] SMP
    CPU: 0 PID: 2541 Comm: CI adapter on d Not tainted 4.7.0-rc1-hosting+ rockchip-linux#49
    Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
    task: ffff880027d7ce00 ti: ffff88003d8f8000 task.ti: ffff88003d8f8000
    RIP: 0010:[<ffffffff812f3d1f>]  [<ffffffff812f3d1f>] dvb_ca_en50221_io_read_condition.isra.7+0x6f/0x150
    RSP: 0018:ffff88003d8fba98  EFLAGS: 00010206
    RAX: 0000000059534255 RBX: 000000753d470f90 RCX: ffff88003c74d181
    RDX: 00000001bea04ba9 RSI: ffff88003d8fbaf4 RDI: 3a3030a56d763fc0
    RBP: ffff88003d8fbae0 R08: ffff88003c74d180 R09: 0000000000000000
    R10: 0000000000000001 R11: 0000000000000000 R12: ffff88003c480e00
    R13: 00000000ffffffff R14: 0000000059534255 R15: 0000000000000000
    FS:  00007fb4209b4700(0000) GS:ffff88003fc00000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 00007f06445f4078 CR3: 000000003c55b000 CR4: 00000000000006b0
    Stack:
     ffff88003d8fbaf4 000000003c2170c0 0000000000004000 0000000000000000
     ffff88003c480e00 ffff88003d8fbc80 ffff88003c74d180 ffff88003d8fbb8c
     0000000000000000 ffff88003d8fbb10 ffffffff812f3e37 ffff88003d8fbb00
    Call Trace:
     [<ffffffff812f3e37>] dvb_ca_en50221_io_poll+0x37/0xa0
     [<ffffffff8113109b>] do_sys_poll+0x2db/0x520

This is a backtrace of the kernel attempting to lock a freed mutex:

    #0  0xffffffff81083d40 in rep_nop () at ./arch/x86/include/asm/processor.h:569
    FireflyTeam#1  cpu_relax () at ./arch/x86/include/asm/processor.h:574
    FireflyTeam#2  virt_spin_lock (lock=<optimized out>) at ./arch/x86/include/asm/qspinlock.h:57
    FireflyTeam#3  native_queued_spin_lock_slowpath (lock=0xffff88003c480e90, val=761492029) at kernel/locking/qspinlock.c:304
    FireflyTeam#4  0xffffffff810d1a06 in pv_queued_spin_lock_slowpath (val=<optimized out>, lock=<optimized out>) at ./arch/x86/include/asm/paravirt.h:669
    FireflyTeam#5  queued_spin_lock_slowpath (val=<optimized out>, lock=<optimized out>) at ./arch/x86/include/asm/qspinlock.h:28
    FireflyTeam#6  queued_spin_lock (lock=<optimized out>) at include/asm-generic/qspinlock.h:107
    FireflyTeam#7  __mutex_lock_common (use_ww_ctx=<optimized out>, ww_ctx=<optimized out>, ip=<optimized out>, nest_lock=<optimized out>, subclass=<optimized out>,
        state=<optimized out>, lock=<optimized out>) at kernel/locking/mutex.c:526
    FireflyTeam#8  mutex_lock_interruptible_nested (lock=0xffff88003c480e88, subclass=<optimized out>) at kernel/locking/mutex.c:647
    FireflyTeam#9  0xffffffff812f49fe in dvb_ca_en50221_io_do_ioctl (file=<optimized out>, cmd=761492029, parg=0x1 <irq_stack_union+1>)
        at drivers/media/dvb-core/dvb_ca_en50221.c:1210
    FireflyTeam#10 0xffffffff812ee660 in dvb_usercopy (file=<optimized out>, cmd=761492029, arg=<optimized out>, func=<optimized out>) at drivers/media/dvb-core/dvbdev.c:883
    FireflyTeam#11 0xffffffff812f3410 in dvb_ca_en50221_io_ioctl (file=<optimized out>, cmd=<optimized out>, arg=<optimized out>) at drivers/media/dvb-core/dvb_ca_en50221.c:1284
    FireflyTeam#12 0xffffffff8112eddd in vfs_ioctl (arg=<optimized out>, cmd=<optimized out>, filp=<optimized out>) at fs/ioctl.c:43
    FireflyTeam#13 do_vfs_ioctl (filp=0xffff88003c480e90, fd=<optimized out>, cmd=<optimized out>, arg=<optimized out>) at fs/ioctl.c:674
    FireflyTeam#14 0xffffffff8112f30c in SYSC_ioctl (arg=<optimized out>, cmd=<optimized out>, fd=<optimized out>) at fs/ioctl.c:689
    FireflyTeam#15 SyS_ioctl (fd=6, cmd=2148298626, arg=140734533693696) at fs/ioctl.c:680
    FireflyTeam#16 0xffffffff8103feb2 in entry_SYSCALL_64 () at arch/x86/entry/entry_64.S:207

Signed-off-by: Max Kellermann <[email protected]>
Signed-off-by: Mauro Carvalho Chehab <[email protected]>
0lvin referenced this issue in free-z4u/roc-rk3328-cc-official Feb 24, 2019
…mgmt()

The lpfc_sli4_scmd_to_wqidx_distr() function expects the scsi_cmnd
'lpfc_cmd->pCmd' not to be null, and point to the midlayer command.

That's not true in the .eh_(device|target|bus)_reset_handler path,
because lpfc_send_taskmgmt() sends commands not from the midlayer, so
does not set 'lpfc_cmd->pCmd'.

That is true in the .queuecommand path because lpfc_queuecommand()
stores the scsi_cmnd from midlayer in lpfc_cmd->pCmd; and lpfc_cmd is
stored by lpfc_scsi_prep_cmnd() in piocbq->context1 -- which is passed
to lpfc_sli4_scmd_to_wqidx_distr() as lpfc_cmd parameter.

This problem can be hit on SCSI EH, and immediately with sg_reset.
These 2 test-cases demonstrate the problem/fix with next-20160601.

Test-case 1) sg_reset

    # strace sg_reset --device /dev/sdm
    <...>
    open("/dev/sdm", O_RDWR|O_NONBLOCK)     = 3
    ioctl(3, SG_SCSI_RESET, 0x3fffde6d0994 <unfinished ...>
    +++ killed by SIGSEGV +++
    Segmentation fault

    # dmesg
    Unable to handle kernel paging request for data at address 0x00000000
    Faulting instruction address: 0xd00000001c88442c
    Oops: Kernel access of bad area, sig: 11 [FireflyTeam#1]
    <...>
    CPU: 104 PID: 16333 Comm: sg_reset Tainted: G        W       4.7.0-rc1-next-20160601-00004-g95b89dc FireflyTeam#6
    <...>
    NIP [d00000001c88442c] lpfc_sli4_scmd_to_wqidx_distr+0xc/0xd0 [lpfc]
    LR [d00000001c826fe8] lpfc_sli_calc_ring.part.27+0x98/0xd0 [lpfc]
    Call Trace:
    [c000003c9ec876f0] [c000003c9ec87770] 0xc000003c9ec87770 (unreliable)
    [c000003c9ec87720] [d00000001c82e004] lpfc_sli_issue_iocb+0xd4/0x260 [lpfc]
    [c000003c9ec87780] [d00000001c831a3c] lpfc_sli_issue_iocb_wait+0x15c/0x5b0 [lpfc]
    [c000003c9ec87880] [d00000001c87f27c] lpfc_send_taskmgmt+0x24c/0x650 [lpfc]
    [c000003c9ec87950] [d00000001c87fd7c] lpfc_device_reset_handler+0x10c/0x200 [lpfc]
    [c000003c9ec87a10] [c000000000610694] scsi_try_bus_device_reset+0x44/0xc0
    [c000003c9ec87a40] [c0000000006113e8] scsi_ioctl_reset+0x198/0x2c0
    [c000003c9ec87bf0] [c00000000060fe5c] scsi_ioctl+0x13c/0x4b0
    [c000003c9ec87c80] [c0000000006629b0] sd_ioctl+0xf0/0x120
    [c000003c9ec87cd0] [c00000000046e4f8] blkdev_ioctl+0x248/0xb70
    [c000003c9ec87d30] [c0000000002a1f60] block_ioctl+0x70/0x90
    [c000003c9ec87d50] [c00000000026d334] do_vfs_ioctl+0xc4/0x890
    [c000003c9ec87de0] [c00000000026db60] SyS_ioctl+0x60/0xc0
    [c000003c9ec87e30] [c000000000009120] system_call+0x38/0x108
    Instruction dump:
    <...>

    With fix:

    # strace sg_reset --device /dev/sdm
    <...>
    open("/dev/sdm", O_RDWR|O_NONBLOCK)     = 3
    ioctl(3, SG_SCSI_RESET, 0x3fffe103c554) = 0
    close(3)                                = 0
    exit_group(0)                           = ?
    +++ exited with 0 +++

    # dmesg
    [  424.658649] lpfc 0006:01:00.4: 4:(0):0713 SCSI layer issued Device Reset (1, 0) return x2002

Test-case 2) SCSI EH

    Using this debug patch to wire an SCSI EH trigger, for lpfc_scsi_cmd_iocb_cmpl():
    -       cmd->scsi_done(cmd);
    +       if ((phba->pport ? phba->pport->cfg_log_verbose : phba->cfg_log_verbose) == 0x32100000)
    +               printk(KERN_ALERT "lpfc: skip scsi_done()\n");
    +       else
    +               cmd->scsi_done(cmd);

    # echo 0x32100000 > /sys/class/scsi_host/host11/lpfc_log_verbose

    # dd if=/dev/sdm of=/dev/null iflag=direct &
    <...>

    After a while:

    # dmesg
    lpfc 0006:01:00.4: 4:(0):3053 lpfc_log_verbose changed from 0 (x0) to 839909376 (x32100000)
    lpfc: skip scsi_done()
    <...>
    Unable to handle kernel paging request for data at address 0x00000000
    Faulting instruction address: 0xd0000000199e448c
    Oops: Kernel access of bad area, sig: 11 [FireflyTeam#1]
    <...>
    CPU: 96 PID: 28556 Comm: scsi_eh_11 Tainted: G        W       4.7.0-rc1-next-20160601-00004-g95b89dc FireflyTeam#6
    <...>
    NIP [d0000000199e448c] lpfc_sli4_scmd_to_wqidx_distr+0xc/0xd0 [lpfc]
    LR [d000000019986fe8] lpfc_sli_calc_ring.part.27+0x98/0xd0 [lpfc]
    Call Trace:
    [c000000ff0d0b890] [c000000ff0d0b900] 0xc000000ff0d0b900 (unreliable)
    [c000000ff0d0b8c0] [d00000001998e004] lpfc_sli_issue_iocb+0xd4/0x260 [lpfc]
    [c000000ff0d0b920] [d000000019991a3c] lpfc_sli_issue_iocb_wait+0x15c/0x5b0 [lpfc]
    [c000000ff0d0ba20] [d0000000199df27c] lpfc_send_taskmgmt+0x24c/0x650 [lpfc]
    [c000000ff0d0baf0] [d0000000199dfd7c] lpfc_device_reset_handler+0x10c/0x200 [lpfc]
    [c000000ff0d0bbb0] [c000000000610694] scsi_try_bus_device_reset+0x44/0xc0
    [c000000ff0d0bbe0] [c0000000006126cc] scsi_eh_ready_devs+0x49c/0x9c0
    [c000000ff0d0bcb0] [c000000000614160] scsi_error_handler+0x580/0x680
    [c000000ff0d0bd80] [c0000000000ae848] kthread+0x108/0x130
    [c000000ff0d0be30] [c0000000000094a8] ret_from_kernel_thread+0x5c/0xb4
    Instruction dump:
    <...>

    With fix:

    # dmesg
    lpfc 0006:01:00.4: 4:(0):3053 lpfc_log_verbose changed from 0 (x0) to 839909376 (x32100000)
    lpfc: skip scsi_done()
    <...>
    lpfc 0006:01:00.4: 4:(0):0713 SCSI layer issued Device Reset (0, 0) return x2002
    <...>
    lpfc 0006:01:00.4: 4:(0):0723 SCSI layer issued Target Reset (1, 0) return x2002
    <...>
    lpfc 0006:01:00.4: 4:(0):0714 SCSI layer issued Bus Reset Data: x2002
    <...>
    lpfc 0006:01:00.4: 4:(0):3172 SCSI layer issued Host Reset Data:
    <...>

Fixes: 8b0dff1 ("lpfc: Add support for using block multi-queue")
Cc: <[email protected]> # v4.2+
Signed-off-by: Mauricio Faria de Oliveira <[email protected]>
Reviewed-by: Johannes Thumshirn <[email protected]>
Acked-by: James Smart <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>
0lvin referenced this issue in free-z4u/roc-rk3328-cc-official Feb 24, 2019
mpt3sas crashes on resume after suspend with WarpDrive flash cards.  The
reply_post_host_index array is not set back up after the resume, and we
deference a stale pointer in _base_interrupt().

[   47.309711] BUG: unable to handle kernel paging request at ffffc90001f8006c
[   47.318289] IP: [<ffffffffc00863ef>] _base_interrupt+0x49f/0xa30 [mpt3sas]
[   47.326749] PGD 41ccaa067 PUD 41ccab067 PMD 3466c067 PTE 0
[   47.333848] Oops: 0002 [FireflyTeam#1] SMP
...
[   47.452708] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.7.0 FireflyTeam#6
[   47.460506] Hardware name: Dell Inc. OptiPlex 990/06D7TR, BIOS A18 09/24/2013
[   47.469629] task: ffffffff81c0d500 ti: ffffffff81c00000 task.ti: ffffffff81c00000
[   47.479112] RIP: 0010:[<ffffffffc00863ef>]  [<ffffffffc00863ef>] _base_interrupt+0x49f/0xa30 [mpt3sas]
[   47.490466] RSP: 0018:ffff88041d203e30  EFLAGS: 00010002
[   47.497801] RAX: 0000000000000001 RBX: ffff880033f4c000 RCX: 0000000000000001
[   47.506973] RDX: ffffc90001f8006c RSI: 0000000000000082 RDI: 0000000000000082
[   47.516141] RBP: ffff88041d203eb0 R08: ffff8804118e2820 R09: 0000000000000001
[   47.525300] R10: 0000000000000001 R11: 00000000100c0000 R12: 0000000000000000
[   47.534457] R13: ffff880412c487e0 R14: ffff88041a8987d8 R15: 0000000000000001
[   47.543632] FS:  0000000000000000(0000) GS:ffff88041d200000(0000) knlGS:0000000000000000
[   47.553796] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   47.561632] CR2: ffffc90001f8006c CR3: 0000000001c06000 CR4: 00000000000406f0
[   47.570883] Stack:
[   47.575015]  000000001d211228 ffff88041d2100c0 ffff8800c47d8130 0000000000000100
[   47.584625]  ffff8804100c0000 100c000000000000 ffff88041a8992a0 ffff88041a8987f8
[   47.594230]  ffff88041d203e00 ffffffff81111e55 000000000000038c ffff880414ad4280
[   47.603862] Call Trace:
[   47.608474]  <IRQ>
[   47.610413]  [<ffffffff81111e55>] ? call_timer_fn+0x35/0x120
[   47.620539]  [<ffffffff81100a1f>] handle_irq_event_percpu+0x7f/0x1c0
[   47.629061]  [<ffffffff81100b8c>] handle_irq_event+0x2c/0x50
[   47.636859]  [<ffffffff81103fff>] handle_edge_irq+0x6f/0x130
[   47.644654]  [<ffffffff8102fbf3>] handle_irq+0x73/0x120
[   47.652011]  [<ffffffff810c6ada>] ? atomic_notifier_call_chain+0x1a/0x20
[   47.660854]  [<ffffffff817e374b>] do_IRQ+0x4b/0xd0
[   47.667777]  [<ffffffff817e160c>] common_interrupt+0x8c/0x8c
[   47.675635]  <EOI>

Move the reply_post_host_index array setup into
mpt3sas_base_map_resources(), which is also in the resume path.

Cc: [email protected]
Signed-off-by: Greg Edwards <[email protected]>
Acked-by: Chaitra P B <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>
0lvin referenced this issue in free-z4u/roc-rk3328-cc-official Feb 28, 2019
On lubbock board, the probe of the driver crashes by dereferencing very
early a platform_data structure which is not set, in
pxa2xx_configure_sockets().

The stack fixed is :
[    0.244353] SA1111 Microprocessor Companion Chip: silicon revision 1, metal revision 1
[    0.256321] sa1111 sa1111: Providing IRQ336-390
[    0.340899] clocksource: Switched to clocksource oscr0
[    0.472263] Unable to handle kernel NULL pointer dereference at virtual address 00000004
[    0.480469] pgd = c0004000
[    0.483432] [00000004] *pgd=00000000
[    0.487105] Internal error: Oops: f5 [FireflyTeam#1] ARM
[    0.491497] Modules linked in:
[    0.494650] CPU: 0 PID: 1 Comm: swapper Not tainted 4.8.0-rc3-00080-g1aaa68426f0c-dirty #2068
[    0.503229] Hardware name: Intel DBPXA250 Development Platform (aka Lubbock)
[    0.510344] task: c3e42000 task.stack: c3e44000
[    0.514984] PC is at pxa2xx_configure_sockets+0x4/0x24 (drivers/pcmcia/pxa2xx_base.c:227)
[    0.520193] LR is at pcmcia_lubbock_init+0x1c/0x38
[    0.525079] pc : [<c0247c30>]    lr : [<c02479b0>]    psr: a0000053
[    0.525079] sp : c3e45e70  ip : 100019ff  fp : 00000000
[    0.536651] r10: c0828900  r9 : c0434838  r8 : 00000000
[    0.541953] r7 : c0820700  r6 : c0857b30  r5 : c3ec1400  r4 : c0820758
[    0.548549] r3 : 00000000  r2 : 0000000c  r1 : c3c09c40  r0 : c3ec1400
[    0.555154] Flags: NzCv  IRQs on  FIQs off  Mode SVC_32  ISA ARM  Segment none
[    0.562450] Control: 0000397f  Table: a0004000  DAC: 00000053
[    0.568257] Process swapper (pid: 1, stack limit = 0xc3e44190)
[    0.574154] Stack: (0xc3e45e70 to 0xc3e46000)
[    0.578610] 5e60:                                     c4849800 00000000 c3ec1400 c024769c
[    0.586928] 5e80: 00000000 c3ec140c c3c0ee0c c3ec1400 c3ec1434 c020c410 c3ec1400 c3ec1434
[    0.595244] 5ea0: c0820700 c080b408 c0828900 c020c5f8 00000000 c0820700 c020c578 c020ac5c
[    0.603560] 5ec0: c3e687cc c3e71e10 c0820700 00000000 c3c02de0 c020bae4 c03c62f7 c03c62f7
[    0.611872] 5ee0: c3e68780 c0820700 c042e034 00000000 c043c440 c020cdec c080b408 00000005
[    0.620188] 5f00: c042e034 c00096c0 c0034440 c01c730c 20000053 ffffffff 00000000 00000000
[    0.628502] 5f20: 00000000 c3ffcb87 c3ffcb90 c00346ac c3e66ba0 c03f7914 00000092 00000005
[    0.636811] 5f40: 00000005 c03f847c 00000091 c03f847c 00000000 00000005 c0434828 00000005
[    0.645125] 5f60: c043482c 00000092 c043c440 c0828900 c0434838 c0418d2c 00000005 00000005
[    0.653430] 5f80: 00000000 c041858c 00000000 c032e9f0 00000000 00000000 00000000 00000000
[    0.661729] 5fa0: 00000000 c032e9f8 00000000 c000f0f0 00000000 00000000 00000000 00000000
[    0.670020] 5fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[    0.678311] 5fe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000
[    0.686673] (pxa2xx_configure_sockets) from pcmcia_lubbock_init (/drivers/pcmcia/sa1111_lubbock.c:161)
[    0.696026] (pcmcia_lubbock_init) from pcmcia_probe (/drivers/pcmcia/sa1111_generic.c:213)
[    0.704358] (pcmcia_probe) from driver_probe_device (/drivers/base/dd.c:378 /drivers/base/dd.c:499)
[    0.712848] (driver_probe_device) from __driver_attach (/./include/linux/device.h:983 /drivers/base/dd.c:733)
[    0.721414] (__driver_attach) from bus_for_each_dev (/drivers/base/bus.c:313)
[    0.729723] (bus_for_each_dev) from bus_add_driver (/drivers/base/bus.c:708)
[    0.738036] (bus_add_driver) from driver_register (/drivers/base/driver.c:169)
[    0.746185] (driver_register) from do_one_initcall (/init/main.c:778)
[    0.754561] (do_one_initcall) from kernel_init_freeable (/init/main.c:843 /init/main.c:851 /init/main.c:869 /init/main.c:1016)
[    0.763409] (kernel_init_freeable) from kernel_init (/init/main.c:944)
[    0.771660] (kernel_init) from ret_from_fork (/arch/arm/kernel/entry-common.S:119)
[ 0.779347] Code: c03c6305 c03c631e c03c632e e5903048 (e993000c)
All code
========
   0:	c03c6305 	eorsgt	r6, ip, r5, lsl FireflyTeam#6
   4:	c03c631e 	eorsgt	r6, ip, lr, lsl r3
   8:	c03c632e 	eorsgt	r6, ip, lr, lsr FireflyTeam#6
   c:	e5903048 	ldr	r3, [r0, rockchip-linux#72]	; 0x48
  10:*	e993000c 	ldmib	r3, {r2, r3}		<-- trapping instruction

Signed-off-by: Robert Jarzmik <[email protected]>
Signed-off-by: Russell King <[email protected]>
0lvin referenced this issue in free-z4u/roc-rk3328-cc-official Feb 28, 2019
Since commit 4d4c474 ("perf/x86/intel/bts: Fix BTS PMI detection")
my box goes boom on boot:

| .... node  #0, CPUs:      FireflyTeam#1 FireflyTeam#2 FireflyTeam#3 FireflyTeam#4 FireflyTeam#5 FireflyTeam#6 FireflyTeam#7
| BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
| IP: [<ffffffff8100c463>] intel_bts_interrupt+0x43/0x130
| Call Trace:
|  <NMI> d [<ffffffff8100b341>] intel_pmu_handle_irq+0x51/0x4b0
|  [<ffffffff81004d47>] perf_event_nmi_handler+0x27/0x40

This happens because the code introduced in this commit dereferences the
debug store pointer unconditionally. The debug store is not guaranteed to
be available, so a NULL pointer check as on other places is required.

Fixes: 4d4c474 ("perf/x86/intel/bts: Fix BTS PMI detection")
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Reviewed-by: Alexander Shishkin <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
0lvin referenced this issue in free-z4u/roc-rk3328-cc-official Mar 10, 2019
First loop in wait_for_xmitr could also trigger NMI
watchdog in case reading from the port is slow:

  PID: 0      TASK: ffffffff819c1460  CPU: 0   COMMAND: "swapper/0"
   #0 [ffff88019f405e58] crash_nmi_callback at ffffffff8104d382
   FireflyTeam#1 [ffff88019f405e68] nmi_handle at ffffffff8168ead9
   FireflyTeam#2 [ffff88019f405eb0] do_nmi at ffffffff8168ec53
   FireflyTeam#3 [ffff88019f405ef0] end_repeat_nmi at ffffffff8168df13
      [exception RIP: delay_tsc+50]
      RIP: ffffffff81325642  RSP: ffff88019f403bb0  RFLAGS: 00000083
      RAX: 00000000000005c8  RBX: ffffffff81f83000  RCX: 0000024e4fb88a8b
      RDX: 0000024e4fb89053  RSI: 0000000000000000  RDI: 00000000000007d1
      RBP: ffff88019f403bb0   R8: 000000000000000a   R9: 0000000000000000
      R10: 0000000000000000  R11: ffff88019f403ad6  R12: 000000000000250f
      R13: 0000000000000020  R14: ffffffff81d360c7  R15: 0000000000000047
      ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
  --- <NMI exception stack> ---
   FireflyTeam#4 [ffff88019f403bb0] delay_tsc at ffffffff81325642
   FireflyTeam#5 [ffff88019f403bb8] __const_udelay at ffffffff813255a8
   FireflyTeam#6 [ffff88019f403bc8] wait_for_xmitr at ffffffff81404390
   FireflyTeam#7 [ffff88019f403bf0] serial8250_console_putchar at ffffffff8140455c
   FireflyTeam#8 [ffff88019f403c10] uart_console_write at ffffffff813ff00a
   FireflyTeam#9 [ffff88019f403c40] serial8250_console_write at ffffffff814044ae
  FireflyTeam#10 [ffff88019f403c88] call_console_drivers.constprop.15 at ffffffff81086b01
  FireflyTeam#11 [ffff88019f403cb0] console_unlock at ffffffff8108842f
  FireflyTeam#12 [ffff88019f403ce8] vprintk_emit at ffffffff81088834
  FireflyTeam#13 [ffff88019f403d58] vprintk_default at ffffffff81088ba9
  FireflyTeam#14 [ffff88019f403d68] printk at ffffffff8167f034

Adding touch_nmi_watchdog call to the first loop as well.

Reported-by: Chunyu Hu <[email protected]>
Signed-off-by: Jiri Olsa <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
rkchrome pushed a commit that referenced this issue Oct 29, 2019
commit cf3591e upstream.

Revert the commit bd293d0. The proper
fix has been made available with commit d0a255e ("loop: set
PF_MEMALLOC_NOIO for the worker thread").

Note that the fix offered by commit bd293d0 doesn't really prevent
the deadlock from occuring - if we look at the stacktrace reported by
Junxiao Bi, we see that it hangs in bit_wait_io and not on the mutex -
i.e. it has already successfully taken the mutex. Changing the mutex
from mutex_lock to mutex_trylock won't help with deadlocks that happen
afterwards.

PID: 474    TASK: ffff8813e11f4600  CPU: 10  COMMAND: "kswapd0"
   #0 [ffff8813dedfb938] __schedule at ffffffff8173f405
   #1 [ffff8813dedfb990] schedule at ffffffff8173fa27
   #2 [ffff8813dedfb9b0] schedule_timeout at ffffffff81742fec
   #3 [ffff8813dedfba60] io_schedule_timeout at ffffffff8173f186
   #4 [ffff8813dedfbaa0] bit_wait_io at ffffffff8174034f
   #5 [ffff8813dedfbac0] __wait_on_bit at ffffffff8173fec8
   #6 [ffff8813dedfbb10] out_of_line_wait_on_bit at ffffffff8173ff81
   #7 [ffff8813dedfbb90] __make_buffer_clean at ffffffffa038736f [dm_bufio]
   #8 [ffff8813dedfbbb0] __try_evict_buffer at ffffffffa0387bb8 [dm_bufio]
   #9 [ffff8813dedfbbd0] dm_bufio_shrink_scan at ffffffffa0387cc3 [dm_bufio]
  #10 [ffff8813dedfbc40] shrink_slab at ffffffff811a87ce
  #11 [ffff8813dedfbd30] shrink_zone at ffffffff811ad778
  #12 [ffff8813dedfbdc0] kswapd at ffffffff811ae92f
  #13 [ffff8813dedfbec0] kthread at ffffffff810a8428
  #14 [ffff8813dedfbf50] ret_from_fork at ffffffff81745242

Signed-off-by: Mikulas Patocka <[email protected]>
Cc: [email protected]
Fixes: bd293d0 ("dm bufio: fix deadlock with loop device")
Depends-on: d0a255e ("loop: set PF_MEMALLOC_NOIO for the worker thread")
Signed-off-by: Mike Snitzer <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
friendlyarm referenced this issue in friendlyarm/kernel-rockchip Feb 26, 2020
commit 42ffb0b upstream.

There exists a deadlock with range_cyclic that has existed forever.  If
we loop around with a bio already built we could deadlock with a writer
who has the page locked that we're attempting to write but is waiting on
a page in our bio to be written out.  The task traces are as follows

  PID: 1329874  TASK: ffff889ebcdf3800  CPU: 33  COMMAND: "kworker/u113:5"
   #0 [ffffc900297bb658] __schedule at ffffffff81a4c33f
   #1 [ffffc900297bb6e0] schedule at ffffffff81a4c6e3
   #2 [ffffc900297bb6f8] io_schedule at ffffffff81a4ca42
   #3 [ffffc900297bb708] __lock_page at ffffffff811f145b
   #4 [ffffc900297bb798] __process_pages_contig at ffffffff814bc502
   #5 [ffffc900297bb8c8] lock_delalloc_pages at ffffffff814bc684
   #6 [ffffc900297bb900] find_lock_delalloc_range at ffffffff814be9ff
   #7 [ffffc900297bb9a0] writepage_delalloc at ffffffff814bebd0
   #8 [ffffc900297bba18] __extent_writepage at ffffffff814bfbf2
   rockchip-linux#9 [ffffc900297bba98] extent_write_cache_pages at ffffffff814bffbd

  PID: 2167901  TASK: ffff889dc6a59c00  CPU: 14  COMMAND:
  "aio-dio-invalid"
   #0 [ffffc9003b50bb18] __schedule at ffffffff81a4c33f
   #1 [ffffc9003b50bba0] schedule at ffffffff81a4c6e3
   #2 [ffffc9003b50bbb8] io_schedule at ffffffff81a4ca42
   #3 [ffffc9003b50bbc8] wait_on_page_bit at ffffffff811f24d6
   #4 [ffffc9003b50bc60] prepare_pages at ffffffff814b05a7
   #5 [ffffc9003b50bcd8] btrfs_buffered_write at ffffffff814b1359
   #6 [ffffc9003b50bdb0] btrfs_file_write_iter at ffffffff814b5933
   #7 [ffffc9003b50be38] new_sync_write at ffffffff8128f6a8
   #8 [ffffc9003b50bec8] vfs_write at ffffffff81292b9d
   rockchip-linux#9 [ffffc9003b50bf00] ksys_pwrite64 at ffffffff81293032

I used drgn to find the respective pages we were stuck on

page_entry.page 0xffffea00fbfc7500 index 8148 bit 15 pid 2167901
page_entry.page 0xffffea00f9bb7400 index 7680 bit 0 pid 1329874

As you can see the kworker is waiting for bit 0 (PG_locked) on index
7680, and aio-dio-invalid is waiting for bit 15 (PG_writeback) on index
8148.  aio-dio-invalid has 7680, and the kworker epd looks like the
following

  crash> struct extent_page_data ffffc900297bbbb0
  struct extent_page_data {
    bio = 0xffff889f747ed830,
    tree = 0xffff889eed6ba448,
    extent_locked = 0,
    sync_io = 0
  }

Probably worth mentioning as well that it waits for writeback of the
page to complete while holding a lock on it (at prepare_pages()).

Using drgn I walked the bio pages looking for page
0xffffea00fbfc7500 which is the one we're waiting for writeback on

  bio = Object(prog, 'struct bio', address=0xffff889f747ed830)
  for i in range(0, bio.bi_vcnt.value_()):
      bv = bio.bi_io_vec[i]
      if bv.bv_page.value_() == 0xffffea00fbfc7500:
	  print("FOUND IT")

which validated what I suspected.

The fix for this is simple, flush the epd before we loop back around to
the beginning of the file during writeout.

Fixes: b293f02 ("Btrfs: Add writepages support")
CC: [email protected] # 4.4+
Reviewed-by: Filipe Manana <[email protected]>
Signed-off-by: Josef Bacik <[email protected]>
Signed-off-by: David Sterba <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
friendlyarm referenced this issue in friendlyarm/kernel-rockchip Feb 26, 2020
[ Upstream commit 576c75e ]

With zpci_disable() working, lockdep detected a potential deadlock
(lockdep output at the end).

The deadlock is between recovering a PCI function via the

/sys/bus/pci/devices/<dev>/recover

attribute vs powering it off via

/sys/bus/pci/slots/<slot>/power.

The fix is analogous to the changes in commit 0ee223b ("scsi: core:
Avoid that SCSI device removal through sysfs triggers a deadlock")
that fixed a potential deadlock on removing a SCSI device via sysfs.

[  204.830107] ======================================================
[  204.830109] WARNING: possible circular locking dependency detected
[  204.830111] 5.5.0-rc2-06072-gbc03ecc9a672 #6 Tainted: G        W
[  204.830112] ------------------------------------------------------
[  204.830113] bash/1034 is trying to acquire lock:
[  204.830115] 0000000192a1a610 (kn->count#200){++++}, at: kernfs_remove_by_name_ns+0x5c/0xa8
[  204.830122]
               but task is already holding lock:
[  204.830123] 00000000c16134a8 (pci_rescan_remove_lock){+.+.}, at: pci_stop_and_remove_bus_device_locked+0x26/0x48
[  204.830128]
               which lock already depends on the new lock.

[  204.830129]
               the existing dependency chain (in reverse order) is:
[  204.830130]
               -> #1 (pci_rescan_remove_lock){+.+.}:
[  204.830134]        validate_chain+0x93a/0xd08
[  204.830136]        __lock_acquire+0x4ae/0x9d0
[  204.830137]        lock_acquire+0x114/0x280
[  204.830140]        __mutex_lock+0xa2/0x960
[  204.830142]        mutex_lock_nested+0x32/0x40
[  204.830145]        recover_store+0x4c/0xa8
[  204.830147]        kernfs_fop_write+0xe6/0x218
[  204.830151]        vfs_write+0xb0/0x1b8
[  204.830152]        ksys_write+0x6c/0xf8
[  204.830154]        system_call+0xd8/0x2d8
[  204.830155]
               -> #0 (kn->count#200){++++}:
[  204.830187]        check_noncircular+0x1e6/0x240
[  204.830189]        check_prev_add+0xfc/0xdb0
[  204.830190]        validate_chain+0x93a/0xd08
[  204.830192]        __lock_acquire+0x4ae/0x9d0
[  204.830193]        lock_acquire+0x114/0x280
[  204.830194]        __kernfs_remove.part.0+0x2e4/0x360
[  204.830196]        kernfs_remove_by_name_ns+0x5c/0xa8
[  204.830198]        remove_files.isra.0+0x4c/0x98
[  204.830199]        sysfs_remove_group+0x66/0xc8
[  204.830201]        sysfs_remove_groups+0x46/0x68
[  204.830204]        device_remove_attrs+0x52/0x90
[  204.830207]        device_del+0x182/0x418
[  204.830208]        pci_remove_bus_device+0x8a/0x130
[  204.830210]        pci_stop_and_remove_bus_device_locked+0x3a/0x48
[  204.830212]        disable_slot+0x68/0x100
[  204.830213]        power_write_file+0x7c/0x130
[  204.830215]        kernfs_fop_write+0xe6/0x218
[  204.830217]        vfs_write+0xb0/0x1b8
[  204.830218]        ksys_write+0x6c/0xf8
[  204.830220]        system_call+0xd8/0x2d8
[  204.830221]
               other info that might help us debug this:

[  204.830223]  Possible unsafe locking scenario:

[  204.830224]        CPU0                    CPU1
[  204.830225]        ----                    ----
[  204.830226]   lock(pci_rescan_remove_lock);
[  204.830227]                                lock(kn->count#200);
[  204.830229]                                lock(pci_rescan_remove_lock);
[  204.830231]   lock(kn->count#200);
[  204.830233]
                *** DEADLOCK ***

[  204.830234] 4 locks held by bash/1034:
[  204.830235]  #0: 00000001b6fbc498 (sb_writers#4){.+.+}, at: vfs_write+0x158/0x1b8
[  204.830239]  #1: 000000018c9f5090 (&of->mutex){+.+.}, at: kernfs_fop_write+0xaa/0x218
[  204.830242]  #2: 00000001f7da0810 (kn->count#235){.+.+}, at: kernfs_fop_write+0xb6/0x218
[  204.830245]  #3: 00000000c16134a8 (pci_rescan_remove_lock){+.+.}, at: pci_stop_and_remove_bus_device_locked+0x26/0x48
[  204.830248]
               stack backtrace:
[  204.830250] CPU: 2 PID: 1034 Comm: bash Tainted: G        W         5.5.0-rc2-06072-gbc03ecc9a672 #6
[  204.830252] Hardware name: IBM 8561 T01 703 (LPAR)
[  204.830253] Call Trace:
[  204.830257]  [<00000000c05e10c0>] show_stack+0x88/0xf0
[  204.830260]  [<00000000c112dca4>] dump_stack+0xa4/0xe0
[  204.830261]  [<00000000c0694c06>] check_noncircular+0x1e6/0x240
[  204.830263]  [<00000000c0695bec>] check_prev_add+0xfc/0xdb0
[  204.830264]  [<00000000c06971da>] validate_chain+0x93a/0xd08
[  204.830266]  [<00000000c06994c6>] __lock_acquire+0x4ae/0x9d0
[  204.830267]  [<00000000c069867c>] lock_acquire+0x114/0x280
[  204.830269]  [<00000000c09ca15c>] __kernfs_remove.part.0+0x2e4/0x360
[  204.830270]  [<00000000c09cb5c4>] kernfs_remove_by_name_ns+0x5c/0xa8
[  204.830272]  [<00000000c09cee14>] remove_files.isra.0+0x4c/0x98
[  204.830274]  [<00000000c09cf2ae>] sysfs_remove_group+0x66/0xc8
[  204.830276]  [<00000000c09cf356>] sysfs_remove_groups+0x46/0x68
[  204.830278]  [<00000000c0e3dfe2>] device_remove_attrs+0x52/0x90
[  204.830280]  [<00000000c0e40382>] device_del+0x182/0x418
[  204.830281]  [<00000000c0dcfd7a>] pci_remove_bus_device+0x8a/0x130
[  204.830283]  [<00000000c0dcfe92>] pci_stop_and_remove_bus_device_locked+0x3a/0x48
[  204.830285]  [<00000000c0de7190>] disable_slot+0x68/0x100
[  204.830286]  [<00000000c0de6514>] power_write_file+0x7c/0x130
[  204.830288]  [<00000000c09cc846>] kernfs_fop_write+0xe6/0x218
[  204.830290]  [<00000000c08f3480>] vfs_write+0xb0/0x1b8
[  204.830291]  [<00000000c08f378c>] ksys_write+0x6c/0xf8
[  204.830293]  [<00000000c1154374>] system_call+0xd8/0x2d8
[  204.830294] INFO: lockdep is turned off.

Signed-off-by: Niklas Schnelle <[email protected]>
Reviewed-by: Peter Oberparleiter <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
friendlyarm referenced this issue in friendlyarm/kernel-rockchip Feb 26, 2020
[ Upstream commit c34f6dc ]

I see the following lockdep splat in the qcom pinctrl driver when
attempting to suspend the device.

 ============================================
 WARNING: possible recursive locking detected
 5.4.2 #2 Tainted: G S
 --------------------------------------------
 cat/6536 is trying to acquire lock:
 ffffff814787ccc0 (&irq_desc_lock_class){-.-.}, at: __irq_get_desc_lock+0x64/0x94

 but task is already holding lock:
 ffffff81436740c0 (&irq_desc_lock_class){-.-.}, at: __irq_get_desc_lock+0x64/0x94

 other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(&irq_desc_lock_class);
   lock(&irq_desc_lock_class);

  *** DEADLOCK ***

  May be due to missing lock nesting notation

 7 locks held by cat/6536:
  #0: ffffff8140e0c420 (sb_writers#7){.+.+}, at: vfs_write+0xc8/0x19c
  #1: ffffff8121eec480 (&of->mutex){+.+.}, at: kernfs_fop_write+0x128/0x1f4
  #2: ffffff8147cad668 (kn->count#263){.+.+}, at: kernfs_fop_write+0x130/0x1f4
  #3: ffffffd011446000 (system_transition_mutex){+.+.}, at: pm_suspend+0x108/0x354
  #4: ffffff814302b970 (&dev->mutex){....}, at: __device_suspend+0x16c/0x420
  #5: ffffff81436740c0 (&irq_desc_lock_class){-.-.}, at: __irq_get_desc_lock+0x64/0x94
  #6: ffffff81479b8c10 (&pctrl->lock){....}, at: msm_gpio_irq_set_wake+0x48/0x7c

 stack backtrace:
 CPU: 4 PID: 6536 Comm: cat Tainted: G S                5.4.2 #2
 Call trace:
  dump_backtrace+0x0/0x174
  show_stack+0x20/0x2c
  dump_stack+0xdc/0x144
  __lock_acquire+0x52c/0x2268
  lock_acquire+0x1dc/0x220
  _raw_spin_lock_irqsave+0x64/0x80
  __irq_get_desc_lock+0x64/0x94
  irq_set_irq_wake+0x40/0x144
  msm_gpio_irq_set_wake+0x5c/0x7c
  set_irq_wake_real+0x40/0x5c
  irq_set_irq_wake+0x70/0x144
  cros_ec_rtc_suspend+0x38/0x4c
  platform_pm_suspend+0x34/0x60
  dpm_run_callback+0x64/0xcc
  __device_suspend+0x314/0x420
  dpm_suspend+0xf8/0x298
  dpm_suspend_start+0x84/0xb4
  suspend_devices_and_enter+0xbc/0x628
  pm_suspend+0x214/0x354
  state_store+0xb0/0x108
  kobj_attr_store+0x14/0x24
  sysfs_kf_write+0x4c/0x64
  kernfs_fop_write+0x158/0x1f4
  __vfs_write+0x54/0x18c
  vfs_write+0xdc/0x19c
  ksys_write+0x7c/0xe4
  __arm64_sys_write+0x20/0x2c
  el0_svc_common+0xa8/0x160
  el0_svc_compat_handler+0x2c/0x38
  el0_svc_compat+0x8/0x10

This is because the msm_gpio_irq_set_wake() function calls
irq_set_irq_wake() as a backup in case the irq comes in during the path
to idle. Given that we're calling irqchip functions from within an
irqchip we need to set the lockdep class to be different for this child
controller vs. the default one that the parent irqchip gets.

This used to be done before this driver was converted to hierarchical
irq domains in commit e35a6ae ("pinctrl/msm: Setup GPIO chip in
hierarchy") via the gpiochip_irq_map() function. With hierarchical irq
domains this function has been replaced by
gpiochip_hierarchy_irq_domain_alloc(). Therefore, set the lockdep class
like was done previously in the irq domain path so we can avoid this
lockdep warning.

Fixes: fdd61a0 ("gpio: Add support for hierarchical IRQ domains")
Cc: Thierry Reding <[email protected]>
Cc: Brian Masney <[email protected]>
Cc: Lina Iyer <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Maulik Shah <[email protected]>
Signed-off-by: Stephen Boyd <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Linus Walleij <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
friendlyarm referenced this issue in friendlyarm/kernel-rockchip Apr 2, 2020
[ Upstream commit 1b6a51e ]

The req->body should be updated before req->state is updated and the
order should be guaranteed by a barrier.

Otherwise, read_reply() might return req->body = NULL.

Below is sample callstack when the issue is reproduced on purpose by
reordering the updates of req->body and req->state and adding delay in
code between updates of req->state and req->body.

[   22.356105] general protection fault: 0000 [#1] SMP PTI
[   22.361185] CPU: 2 PID: 52 Comm: xenwatch Not tainted 5.5.0xen+ #6
[   22.366727] Hardware name: Xen HVM domU, BIOS ...
[   22.372245] RIP: 0010:_parse_integer_fixup_radix+0x6/0x60
... ...
[   22.392163] RSP: 0018:ffffb2d64023fdf0 EFLAGS: 00010246
[   22.395933] RAX: 0000000000000000 RBX: 75746e7562755f6d RCX: 0000000000000000
[   22.400871] RDX: 0000000000000000 RSI: ffffb2d64023fdfc RDI: 75746e7562755f6d
[   22.405874] RBP: 0000000000000000 R08: 00000000000001e8 R09: 0000000000cdcdcd
[   22.410945] R10: ffffb2d6402ffe00 R11: ffff9d95395eaeb0 R12: ffff9d9535935000
[   22.417613] R13: ffff9d9526d4a000 R14: ffff9d9526f4f340 R15: ffff9d9537654000
[   22.423726] FS:  0000000000000000(0000) GS:ffff9d953bc80000(0000) knlGS:0000000000000000
[   22.429898] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   22.434342] CR2: 000000c4206a9000 CR3: 00000001ea3fc002 CR4: 00000000001606e0
[   22.439645] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   22.444941] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   22.450342] Call Trace:
[   22.452509]  simple_strtoull+0x27/0x70
[   22.455572]  xenbus_transaction_start+0x31/0x50
[   22.459104]  netback_changed+0x76c/0xcc1 [xen_netfront]
[   22.463279]  ? find_watch+0x40/0x40
[   22.466156]  xenwatch_thread+0xb4/0x150
[   22.469309]  ? wait_woken+0x80/0x80
[   22.472198]  kthread+0x10e/0x130
[   22.474925]  ? kthread_park+0x80/0x80
[   22.477946]  ret_from_fork+0x35/0x40
[   22.480968] Modules linked in: xen_kbdfront xen_fbfront(+) xen_netfront xen_blkfront
[   22.486783] ---[ end trace a9222030a747c3f7 ]---
[   22.490424] RIP: 0010:_parse_integer_fixup_radix+0x6/0x60

The virt_rmb() is added in the 'true' path of test_reply(). The "while"
is changed to "do while" so that test_reply() is used as a read memory
barrier.

Signed-off-by: Dongli Zhang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Julien Grall <[email protected]>
Signed-off-by: Boris Ostrovsky <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
fanck0605 referenced this issue in fanck0605/friendlywrt-kernel Apr 27, 2020
[ Upstream commit 1bc7896 ]

When experimenting with bpf_send_signal() helper in our production
environment (5.2 based), we experienced a deadlock in NMI mode:
   friendlyarm#5 [ffffc9002219f770] queued_spin_lock_slowpath at ffffffff8110be24
   friendlyarm#6 [ffffc9002219f770] _raw_spin_lock_irqsave at ffffffff81a43012
   friendlyarm#7 [ffffc9002219f780] try_to_wake_up at ffffffff810e7ecd
   friendlyarm#8 [ffffc9002219f7e0] signal_wake_up_state at ffffffff810c7b55
   rockchip-linux#9 [ffffc9002219f7f0] __send_signal at ffffffff810c8602
  rockchip-linux#10 [ffffc9002219f830] do_send_sig_info at ffffffff810ca31a
  rockchip-linux#11 [ffffc9002219f868] bpf_send_signal at ffffffff8119d227
  rockchip-linux#12 [ffffc9002219f988] bpf_overflow_handler at ffffffff811d4140
  rockchip-linux#13 [ffffc9002219f9e0] __perf_event_overflow at ffffffff811d68cf
  rockchip-linux#14 [ffffc9002219fa10] perf_swevent_overflow at ffffffff811d6a09
  rockchip-linux#15 [ffffc9002219fa38] ___perf_sw_event at ffffffff811e0f47
  rockchip-linux#16 [ffffc9002219fc30] __schedule at ffffffff81a3e04d
  rockchip-linux#17 [ffffc9002219fc90] schedule at ffffffff81a3e219
  rockchip-linux#18 [ffffc9002219fca0] futex_wait_queue_me at ffffffff8113d1b9
  rockchip-linux#19 [ffffc9002219fcd8] futex_wait at ffffffff8113e529
  rockchip-linux#20 [ffffc9002219fdf0] do_futex at ffffffff8113ffbc
  rockchip-linux#21 [ffffc9002219fec0] __x64_sys_futex at ffffffff81140d1c
  rockchip-linux#22 [ffffc9002219ff38] do_syscall_64 at ffffffff81002602
  rockchip-linux#23 [ffffc9002219ff50] entry_SYSCALL_64_after_hwframe at ffffffff81c00068

The above call stack is actually very similar to an issue
reported by Commit eac9153 ("bpf/stackmap: Fix deadlock with
rq_lock in bpf_get_stack()") by Song Liu. The only difference is
bpf_send_signal() helper instead of bpf_get_stack() helper.

The above deadlock is triggered with a perf_sw_event.
Similar to Commit eac9153, the below almost identical reproducer
used tracepoint point sched/sched_switch so the issue can be easily caught.
  /* stress_test.c */
  #include <stdio.h>
  #include <stdlib.h>
  #include <sys/mman.h>
  #include <pthread.h>
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <fcntl.h>

  #define THREAD_COUNT 1000
  char *filename;
  void *worker(void *p)
  {
        void *ptr;
        int fd;
        char *pptr;

        fd = open(filename, O_RDONLY);
        if (fd < 0)
                return NULL;
        while (1) {
                struct timespec ts = {0, 1000 + rand() % 2000};

                ptr = mmap(NULL, 4096 * 64, PROT_READ, MAP_PRIVATE, fd, 0);
                usleep(1);
                if (ptr == MAP_FAILED) {
                        printf("failed to mmap\n");
                        break;
                }
                munmap(ptr, 4096 * 64);
                usleep(1);
                pptr = malloc(1);
                usleep(1);
                pptr[0] = 1;
                usleep(1);
                free(pptr);
                usleep(1);
                nanosleep(&ts, NULL);
        }
        close(fd);
        return NULL;
  }

  int main(int argc, char *argv[])
  {
        void *ptr;
        int i;
        pthread_t threads[THREAD_COUNT];

        if (argc < 2)
                return 0;

        filename = argv[1];

        for (i = 0; i < THREAD_COUNT; i++) {
                if (pthread_create(threads + i, NULL, worker, NULL)) {
                        fprintf(stderr, "Error creating thread\n");
                        return 0;
                }
        }

        for (i = 0; i < THREAD_COUNT; i++)
                pthread_join(threads[i], NULL);
        return 0;
  }
and the following command:
  1. run `stress_test /bin/ls` in one windown
  2. hack bcc trace.py with the following change:
#     --- a/tools/trace.py
#     +++ b/tools/trace.py
     @@ -513,6 +513,7 @@ BPF_PERF_OUTPUT(%s);
              __data.tgid = __tgid;
              __data.pid = __pid;
              bpf_get_current_comm(&__data.comm, sizeof(__data.comm));
     +        bpf_send_signal(10);
      %s
      %s
              %s.perf_submit(%s, &__data, sizeof(__data));
  3. in a different window run
     ./trace.py -p $(pidof stress_test) t:sched:sched_switch

The deadlock can be reproduced in our production system.

Similar to Song's fix, the fix is to delay sending signal if
irqs is disabled to avoid deadlocks involving with rq_lock.
With this change, my above stress-test in our production system
won't cause deadlock any more.

I also implemented a scale-down version of reproducer in the
selftest (a subsequent commit). With latest bpf-next,
it complains for the following potential deadlock.
  [   32.832450] -> friendlyarm#1 (&p->pi_lock){-.-.}:
  [   32.833100]        _raw_spin_lock_irqsave+0x44/0x80
  [   32.833696]        task_rq_lock+0x2c/0xa0
  [   32.834182]        task_sched_runtime+0x59/0xd0
  [   32.834721]        thread_group_cputime+0x250/0x270
  [   32.835304]        thread_group_cputime_adjusted+0x2e/0x70
  [   32.835959]        do_task_stat+0x8a7/0xb80
  [   32.836461]        proc_single_show+0x51/0xb0
  ...
  [   32.839512] -> #0 (&(&sighand->siglock)->rlock){....}:
  [   32.840275]        __lock_acquire+0x1358/0x1a20
  [   32.840826]        lock_acquire+0xc7/0x1d0
  [   32.841309]        _raw_spin_lock_irqsave+0x44/0x80
  [   32.841916]        __lock_task_sighand+0x79/0x160
  [   32.842465]        do_send_sig_info+0x35/0x90
  [   32.842977]        bpf_send_signal+0xa/0x10
  [   32.843464]        bpf_prog_bc13ed9e4d3163e3_send_signal_tp_sched+0x465/0x1000
  [   32.844301]        trace_call_bpf+0x115/0x270
  [   32.844809]        perf_trace_run_bpf_submit+0x4a/0xc0
  [   32.845411]        perf_trace_sched_switch+0x10f/0x180
  [   32.846014]        __schedule+0x45d/0x880
  [   32.846483]        schedule+0x5f/0xd0
  ...

  [   32.853148] Chain exists of:
  [   32.853148]   &(&sighand->siglock)->rlock --> &p->pi_lock --> &rq->lock
  [   32.853148]
  [   32.854451]  Possible unsafe locking scenario:
  [   32.854451]
  [   32.855173]        CPU0                    CPU1
  [   32.855745]        ----                    ----
  [   32.856278]   lock(&rq->lock);
  [   32.856671]                                lock(&p->pi_lock);
  [   32.857332]                                lock(&rq->lock);
  [   32.857999]   lock(&(&sighand->siglock)->rlock);

  Deadlock happens on CPU0 when it tries to acquire &sighand->siglock
  but it has been held by CPU1 and CPU1 tries to grab &rq->lock
  and cannot get it.

  This is not exactly the callstack in our production environment,
  but sympotom is similar and both locks are using spin_lock_irqsave()
  to acquire the lock, and both involves rq_lock. The fix to delay
  sending signal when irq is disabled also fixed this issue.

Signed-off-by: Yonghong Song <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Cc: Song Liu <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
fanck0605 referenced this issue in fanck0605/friendlywrt-kernel Apr 27, 2020
commit 791c13b upstream.

Undefined rproc_ops .kick method in remoteproc driver will result in
"Unable to handle kernel NULL pointer dereference" in rproc_virtio_notify,
after firmware loading if:

 1) .kick method wasn't defined in driver
 2) resource_table exists in firmware and has "Virtio device entry" defined

Let's refuse to register an rproc-induced virtio device if no kick method was
defined for rproc.

[   13.180049][  T415] 8<--- cut here ---
[   13.190558][  T415] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[   13.212544][  T415] pgd = (ptrval)
[   13.217052][  T415] [00000000] *pgd=00000000
[   13.224692][  T415] Internal error: Oops: 80000005 [friendlyarm#1] PREEMPT SMP ARM
[   13.231318][  T415] Modules linked in: rpmsg_char imx_rproc virtio_rpmsg_bus rpmsg_core [last unloaded: imx_rproc]
[   13.241687][  T415] CPU: 0 PID: 415 Comm: unload-load.sh Not tainted 5.5.2-00002-g707df13bbbdd friendlyarm#6
[   13.250561][  T415] Hardware name: Freescale i.MX7 Dual (Device Tree)
[   13.257009][  T415] PC is at 0x0
[   13.260249][  T415] LR is at rproc_virtio_notify+0x2c/0x54
[   13.265738][  T415] pc : [<00000000>]    lr : [<8050f6b0>]    psr: 60010113
[   13.272702][  T415] sp : b8d47c48  ip : 00000001  fp : bc04de00
[   13.278625][  T415] r10: bc04c000  r9 : 00000cc0  r8 : b8d46000
[   13.284548][  T415] r7 : 00000000  r6 : b898f200  r5 : 00000000  r4 : b8a29800
[   13.291773][  T415] r3 : 00000000  r2 : 990a3ad4  r1 : 00000000  r0 : b8a29800
[   13.299000][  T415] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
[   13.306833][  T415] Control: 10c5387d  Table: b8b4806a  DAC: 00000051
[   13.313278][  T415] Process unload-load.sh (pid: 415, stack limit = 0x(ptrval))
[   13.320591][  T415] Stack: (0xb8d47c48 to 0xb8d48000)
[   13.325651][  T415] 7c40:                   b895b680 00000001 b898f200 803c6430 b895bc80 7f00ae18
[   13.334531][  T415] 7c60: 00000035 00000000 00000000 b9393200 80b3ed80 00004000 b9393268 bbf5a9a2
[   13.343410][  T415] 7c80: 00000e00 00000200 00000000 7f00aff0 7f00a014 b895b680 b895b800 990a3ad4
[   13.352290][  T415] 7ca0: 00000001 b898f210 b898f200 00000000 00000000 7f00e000 00000001 00000000
[   13.361170][  T415] 7cc0: 00000000 803c62e0 80b2169c 802a0924 b898f210 00000000 00000000 b898f210
[   13.370049][  T415] 7ce0: 80b9ba44 00000000 80b9ba48 00000000 7f00e000 00000008 80b2169c 80400114
[   13.378929][  T415] 7d00: 80b2169c 8061fd64 b898f210 7f00e000 80400744 b8d46000 80b21634 80b21634
[   13.387809][  T415] 7d20: 80b2169c 80400614 80b21634 80400718 7f00e000 00000000 b8d47d7c 80400744
[   13.396689][  T415] 7d40: b8d46000 80b21634 80b21634 803fe338 b898f254 b80fe76c b8d32e38 990a3ad4
[   13.405569][  T415] 7d60: fffffff3 b898f210 b8d46000 00000001 b898f254 803ffe7c 80857a90 b898f210
[   13.414449][  T415] 7d80: 00000001 990a3ad4 b8d46000 b898f210 b898f210 80b17aec b8a29c20 803ff0a4
[   13.423328][  T415] 7da0: b898f210 00000000 b8d46000 803fb8e0 b898f200 00000000 80b17aec b898f210
[   13.432209][  T415] 7dc0: b8a29c20 990a3ad4 b895b900 b898f200 8050fb7c 80b17aec b898f210 b8a29c20
[   13.441088][  T415] 7de0: b8a29800 b895b900 b8a29a04 803c5ec0 b8a29c00 b898f200 b8a29a20 00000007
[   13.449968][  T415] 7e00: b8a29c20 8050fd78 b8a29800 00000000 b8a29a20 b8a29c04 b8a29820 b8a299d0
[   13.458848][  T415] 7e20: b895b900 8050e5a4 b8a29800 b8a299d8 b8d46000 b8a299e0 b8a29820 b8a299d0
[   13.467728][  T415] 7e40: b895b900 8050e008 000041ed 00000000 b8b8c440 b8a299d8 b8a299e0 b8a299d8
[   13.476608][  T415] 7e60: b8b8c440 990a3ad4 00000000 b8a29820 b8b8c400 00000006 b8a29800 b895b880
[   13.485487][  T415] 7e80: b8d47f78 00000000 00000000 8050f4b4 00000006 b895b890 b8b8c400 008fbea0
[   13.494367][  T415] 7ea0: b895b880 8029f530 00000000 00000000 b8d46000 00000006 b8d46000 008fbea0
[   13.503246][  T415] 7ec0: 8029f434 00000000 b8d46000 00000000 00000000 8021e2e4 0000000a 8061fd0c
[   13.512125][  T415] 7ee0: 0000000a b8af0c00 0000000a b8af0c40 00000001 b8af0c40 00000000 8061f910
[   13.521005][  T415] 7f00: 0000000a 80240af4 00000002 b8d46000 00000000 8061fd0c 00000002 80232d7c
[   13.529884][  T415] 7f20: 00000000 b8d46000 00000000 990a3ad4 00000000 00000006 b8a62d80 008fbea0
[   13.538764][  T415] 7f40: b8d47f78 00000000 b8d46000 00000000 00000000 802210c0 b88f2900 00000000
[   13.547644][  T415] 7f60: b8a62d80 b8a62d80 b8d46000 00000006 008fbea0 80221320 00000000 00000000
[   13.556524][  T415] 7f80: b8af0c00 990a3ad4 0000006c 008fbea0 76f1cda0 00000004 80101204 00000004
[   13.565403][  T415] 7fa0: 00000000 80101000 0000006c 008fbea0 00000001 008fbea0 00000006 00000000
[   13.574283][  T415] 7fc0: 0000006c 008fbea0 76f1cda0 00000004 00000006 00000006 00000000 00000000
[   13.583162][  T415] 7fe0: 00000004 7ebaf7d0 76eb4c0b 76e3f206 600d0030 00000001 00000000 00000000
[   13.592056][  T415] [<8050f6b0>] (rproc_virtio_notify) from [<803c6430>] (virtqueue_notify+0x1c/0x34)
[   13.601298][  T415] [<803c6430>] (virtqueue_notify) from [<7f00ae18>] (rpmsg_probe+0x280/0x380 [virtio_rpmsg_bus])
[   13.611663][  T415] [<7f00ae18>] (rpmsg_probe [virtio_rpmsg_bus]) from [<803c62e0>] (virtio_dev_probe+0x1f8/0x2c4)
[   13.622022][  T415] [<803c62e0>] (virtio_dev_probe) from [<80400114>] (really_probe+0x200/0x450)
[   13.630817][  T415] [<80400114>] (really_probe) from [<80400614>] (driver_probe_device+0x16c/0x1ac)
[   13.639873][  T415] [<80400614>] (driver_probe_device) from [<803fe338>] (bus_for_each_drv+0x84/0xc8)
[   13.649102][  T415] [<803fe338>] (bus_for_each_drv) from [<803ffe7c>] (__device_attach+0xd4/0x164)
[   13.658069][  T415] [<803ffe7c>] (__device_attach) from [<803ff0a4>] (bus_probe_device+0x84/0x8c)
[   13.666950][  T415] [<803ff0a4>] (bus_probe_device) from [<803fb8e0>] (device_add+0x444/0x768)
[   13.675572][  T415] [<803fb8e0>] (device_add) from [<803c5ec0>] (register_virtio_device+0xa4/0xfc)
[   13.684541][  T415] [<803c5ec0>] (register_virtio_device) from [<8050fd78>] (rproc_add_virtio_dev+0xcc/0x1b8)
[   13.694466][  T415] [<8050fd78>] (rproc_add_virtio_dev) from [<8050e5a4>] (rproc_start+0x148/0x200)
[   13.703521][  T415] [<8050e5a4>] (rproc_start) from [<8050e008>] (rproc_boot+0x384/0x5c0)
[   13.711708][  T415] [<8050e008>] (rproc_boot) from [<8050f4b4>] (state_store+0x3c/0xc8)
[   13.719723][  T415] [<8050f4b4>] (state_store) from [<8029f530>] (kernfs_fop_write+0xfc/0x214)
[   13.728348][  T415] [<8029f530>] (kernfs_fop_write) from [<8021e2e4>] (__vfs_write+0x30/0x1cc)
[   13.736971][  T415] [<8021e2e4>] (__vfs_write) from [<802210c0>] (vfs_write+0xac/0x17c)
[   13.744985][  T415] [<802210c0>] (vfs_write) from [<80221320>] (ksys_write+0x64/0xe4)
[   13.752825][  T415] [<80221320>] (ksys_write) from [<80101000>] (ret_fast_syscall+0x0/0x54)
[   13.761178][  T415] Exception stack(0xb8d47fa8 to 0xb8d47ff0)
[   13.766932][  T415] 7fa0:                   0000006c 008fbea0 00000001 008fbea0 00000006 00000000
[   13.775811][  T415] 7fc0: 0000006c 008fbea0 76f1cda0 00000004 00000006 00000006 00000000 00000000
[   13.784687][  T415] 7fe0: 00000004 7ebaf7d0 76eb4c0b 76e3f206
[   13.790442][  T415] Code: bad PC value
[   13.839214][  T415] ---[ end trace 1fe21ecfc9f28852 ]---

Reviewed-by: Mathieu Poirier <[email protected]>
Signed-off-by: Nikita Shubin <[email protected]>
Fixes: 7a18694 ("remoteproc: remove the single rpmsg vdev limitation")
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Bjorn Andersson <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
fanck0605 referenced this issue in fanck0605/friendlywrt-kernel Apr 27, 2020
[ Upstream commit a866759 ]

This reverts commit 64e62bd.

This commit ends up causing some lockdep splats due to trying to grab the
payload lock while holding the mgr's lock:

[   54.010099]
[   54.011765] ======================================================
[   54.018670] WARNING: possible circular locking dependency detected
[   54.025577] 5.5.0-rc6-02274-g77381c23ee63 rockchip-linux#47 Not tainted
[   54.031610] ------------------------------------------------------
[   54.038516] kworker/1:6/1040 is trying to acquire lock:
[   54.044354] ffff888272af3228 (&mgr->payload_lock){+.+.}, at:
drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4
[   54.054957]
[   54.054957] but task is already holding lock:
[   54.061473] ffff888272af3060 (&mgr->lock){+.+.}, at:
drm_dp_mst_topology_mgr_set_mst+0x3c/0x2e4
[   54.071193]
[   54.071193] which lock already depends on the new lock.
[   54.071193]
[   54.080334]
[   54.080334] the existing dependency chain (in reverse order) is:
[   54.088697]
[   54.088697] -> friendlyarm#1 (&mgr->lock){+.+.}:
[   54.094440]        __mutex_lock+0xc3/0x498
[   54.099015]        drm_dp_mst_topology_get_port_validated+0x25/0x80
[   54.106018]        drm_dp_update_payload_part1+0xa2/0x2e2
[   54.112051]        intel_mst_pre_enable_dp+0x144/0x18f
[   54.117791]        intel_encoders_pre_enable+0x63/0x70
[   54.123532]        hsw_crtc_enable+0xa1/0x722
[   54.128396]        intel_update_crtc+0x50/0x194
[   54.133455]        skl_commit_modeset_enables+0x40c/0x540
[   54.139485]        intel_atomic_commit_tail+0x5f7/0x130d
[   54.145418]        intel_atomic_commit+0x2c8/0x2d8
[   54.150770]        drm_atomic_helper_set_config+0x5a/0x70
[   54.156801]        drm_mode_setcrtc+0x2ab/0x833
[   54.161862]        drm_ioctl+0x2e5/0x424
[   54.166242]        vfs_ioctl+0x21/0x2f
[   54.170426]        do_vfs_ioctl+0x5fb/0x61e
[   54.175096]        ksys_ioctl+0x55/0x75
[   54.179377]        __x64_sys_ioctl+0x1a/0x1e
[   54.184146]        do_syscall_64+0x5c/0x6d
[   54.188721]        entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   54.194946]
[   54.194946] -> #0 (&mgr->payload_lock){+.+.}:
[   54.201463]
[   54.201463] other info that might help us debug this:
[   54.201463]
[   54.210410]  Possible unsafe locking scenario:
[   54.210410]
[   54.217025]        CPU0                    CPU1
[   54.222082]        ----                    ----
[   54.227138]   lock(&mgr->lock);
[   54.230643]                                lock(&mgr->payload_lock);
[   54.237742]                                lock(&mgr->lock);
[   54.244062]   lock(&mgr->payload_lock);
[   54.248346]
[   54.248346]  *** DEADLOCK ***
[   54.248346]
[   54.254959] 7 locks held by kworker/1:6/1040:
[   54.259822]  #0: ffff888275c4f528 ((wq_completion)events){+.+.},
at: worker_thread+0x455/0x6e2
[   54.269451]  friendlyarm#1: ffffc9000119beb0
((work_completion)(&(&dev_priv->hotplug.hotplug_work)->work)){+.+.},
at: worker_thread+0x455/0x6e2
[   54.282768]  friendlyarm#2: ffff888272a403f0 (&dev->mode_config.mutex){+.+.},
at: i915_hotplug_work_func+0x4b/0x2be
[   54.293368]  friendlyarm#3: ffffffff824fc6c0 (drm_connector_list_iter){.+.+},
at: i915_hotplug_work_func+0x17e/0x2be
[   54.304061]  friendlyarm#4: ffffc9000119bc58 (crtc_ww_class_acquire){+.+.},
at: drm_helper_probe_detect_ctx+0x40/0xfd
[   54.314855]  friendlyarm#5: ffff888272a40470 (crtc_ww_class_mutex){+.+.}, at:
drm_modeset_lock+0x74/0xe2
[   54.324385]  friendlyarm#6: ffff888272af3060 (&mgr->lock){+.+.}, at:
drm_dp_mst_topology_mgr_set_mst+0x3c/0x2e4
[   54.334597]
[   54.334597] stack backtrace:
[   54.339464] CPU: 1 PID: 1040 Comm: kworker/1:6 Not tainted
5.5.0-rc6-02274-g77381c23ee63 rockchip-linux#47
[   54.348893] Hardware name: Google Fizz/Fizz, BIOS
Google_Fizz.10139.39.0 01/04/2018
[   54.357451] Workqueue: events i915_hotplug_work_func
[   54.362995] Call Trace:
[   54.365724]  dump_stack+0x71/0x9c
[   54.369427]  check_noncircular+0x91/0xbc
[   54.373809]  ? __lock_acquire+0xc9e/0xf66
[   54.378286]  ? __lock_acquire+0xc9e/0xf66
[   54.382763]  ? lock_acquire+0x175/0x1ac
[   54.387048]  ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4
[   54.393177]  ? __mutex_lock+0xc3/0x498
[   54.397362]  ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4
[   54.403492]  ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4
[   54.409620]  ? drm_dp_dpcd_access+0xd9/0x101
[   54.414390]  ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4
[   54.420517]  ? drm_dp_mst_topology_mgr_set_mst+0x218/0x2e4
[   54.426645]  ? intel_digital_port_connected+0x34d/0x35c
[   54.432482]  ? intel_dp_detect+0x227/0x44e
[   54.437056]  ? ww_mutex_lock+0x49/0x9a
[   54.441242]  ? drm_helper_probe_detect_ctx+0x75/0xfd
[   54.446789]  ? intel_encoder_hotplug+0x4b/0x97
[   54.451752]  ? intel_ddi_hotplug+0x61/0x2e0
[   54.456423]  ? mark_held_locks+0x53/0x68
[   54.460803]  ? _raw_spin_unlock_irqrestore+0x3a/0x51
[   54.466347]  ? lockdep_hardirqs_on+0x187/0x1a4
[   54.471310]  ? drm_connector_list_iter_next+0x89/0x9a
[   54.476953]  ? i915_hotplug_work_func+0x206/0x2be
[   54.482208]  ? worker_thread+0x4d5/0x6e2
[   54.486587]  ? worker_thread+0x455/0x6e2
[   54.490966]  ? queue_work_on+0x64/0x64
[   54.495151]  ? kthread+0x1e9/0x1f1
[   54.498946]  ? queue_work_on+0x64/0x64
[   54.503130]  ? kthread_unpark+0x5e/0x5e
[   54.507413]  ? ret_from_fork+0x3a/0x50

The proper fix for this is probably cleanup the VCPI allocations when we're
enabling the topology, or on the first payload allocation. For now though,
let's just revert.

Signed-off-by: Lyude Paul <[email protected]>
Fixes: 64e62bd ("drm/dp_mst: Remove VCPI while disabling topology mgr")
Cc: Sean Paul <[email protected]>
Cc: Wayne Lin <[email protected]>
Reviewed-by: Sean Paul <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
fanck0605 referenced this issue in fanck0605/friendlywrt-kernel Jun 10, 2020
[ Upstream commit 20a785a ]

This BUG halt was reported a while back, but the patch somehow got
missed:

PID: 2879   TASK: c16adaa0  CPU: 1   COMMAND: "sctpn"
 #0 [f418dd28] crash_kexec at c04a7d8c
 friendlyarm#1 [f418dd7c] oops_end at c0863e02
 friendlyarm#2 [f418dd90] do_invalid_op at c040aaca
 friendlyarm#3 [f418de28] error_code (via invalid_op) at c08631a5
    EAX: f34baac0  EBX: 00000090  ECX: f418deb0  EDX: f5542950  EBP: 00000000
    DS:  007b      ESI: f34ba800  ES:  007b      EDI: f418dea0  GS:  00e0
    CS:  0060      EIP: c046fa5e  ERR: ffffffff  EFLAGS: 00010286
 friendlyarm#4 [f418de5c] add_timer at c046fa5e
 friendlyarm#5 [f418de68] sctp_do_sm at f8db8c77 [sctp]
 friendlyarm#6 [f418df30] sctp_primitive_SHUTDOWN at f8dcc1b5 [sctp]
 friendlyarm#7 [f418df48] inet_shutdown at c080baf9
 friendlyarm#8 [f418df5c] sys_shutdown at c079eedf
 rockchip-linux#9 [f418df70] sys_socketcall at c079fe88
    EAX: ffffffda  EBX: 0000000d  ECX: bfceea90  EDX: 0937af98
    DS:  007b      ESI: 0000000c  ES:  007b      EDI: b7150ae4
    SS:  007b      ESP: bfceea7c  EBP: bfceeaa8  GS:  0033
    CS:  0073      EIP: b775c424  ERR: 00000066  EFLAGS: 00000282

It appears that the side effect that starts the shutdown timer was processed
multiple times, which can happen as multiple paths can trigger it.  This of
course leads to the BUG halt in add_timer getting called.

Fix seems pretty straightforward, just check before the timer is added if its
already been started.  If it has mod the timer instead to min(current
expiration, new expiration)

Its been tested but not confirmed to fix the problem, as the issue has only
occured in production environments where test kernels are enjoined from being
installed.  It appears to be a sane fix to me though.  Also, recentely,
Jere found a reproducer posted on list to confirm that this resolves the
issues

Signed-off-by: Neil Horman <[email protected]>
CC: Vlad Yasevich <[email protected]>
CC: "David S. Miller" <[email protected]>
CC: [email protected]
CC: [email protected]
CC: [email protected]
Acked-by: Marcelo Ricardo Leitner <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
friendlyarm referenced this issue in friendlyarm/kernel-rockchip Aug 31, 2020
[ Upstream commit e24c644 ]

I compiled with AddressSanitizer and I had these memory leaks while I
was using the tep_parse_format function:

    Direct leak of 28 byte(s) in 4 object(s) allocated from:
        #0 0x7fb07db49ffe in __interceptor_realloc (/lib/x86_64-linux-gnu/libasan.so.5+0x10dffe)
        #1 0x7fb07a724228 in extend_token /home/pduplessis/repo/linux/tools/lib/traceevent/event-parse.c:985
        #2 0x7fb07a724c21 in __read_token /home/pduplessis/repo/linux/tools/lib/traceevent/event-parse.c:1140
        #3 0x7fb07a724f78 in read_token /home/pduplessis/repo/linux/tools/lib/traceevent/event-parse.c:1206
        #4 0x7fb07a725191 in __read_expect_type /home/pduplessis/repo/linux/tools/lib/traceevent/event-parse.c:1291
        #5 0x7fb07a7251df in read_expect_type /home/pduplessis/repo/linux/tools/lib/traceevent/event-parse.c:1299
        #6 0x7fb07a72e6c8 in process_dynamic_array_len /home/pduplessis/repo/linux/tools/lib/traceevent/event-parse.c:2849
        #7 0x7fb07a7304b8 in process_function /home/pduplessis/repo/linux/tools/lib/traceevent/event-parse.c:3161
        #8 0x7fb07a730900 in process_arg_token /home/pduplessis/repo/linux/tools/lib/traceevent/event-parse.c:3207
        rockchip-linux#9 0x7fb07a727c0b in process_arg /home/pduplessis/repo/linux/tools/lib/traceevent/event-parse.c:1786
        rockchip-linux#10 0x7fb07a731080 in event_read_print_args /home/pduplessis/repo/linux/tools/lib/traceevent/event-parse.c:3285
        rockchip-linux#11 0x7fb07a731722 in event_read_print /home/pduplessis/repo/linux/tools/lib/traceevent/event-parse.c:3369
        rockchip-linux#12 0x7fb07a740054 in __tep_parse_format /home/pduplessis/repo/linux/tools/lib/traceevent/event-parse.c:6335
        rockchip-linux#13 0x7fb07a74047a in __parse_event /home/pduplessis/repo/linux/tools/lib/traceevent/event-parse.c:6389
        rockchip-linux#14 0x7fb07a740536 in tep_parse_format /home/pduplessis/repo/linux/tools/lib/traceevent/event-parse.c:6431
        rockchip-linux#15 0x7fb07a785acf in parse_event ../../../src/fs-src/fs.c:251
        rockchip-linux#16 0x7fb07a785ccd in parse_systems ../../../src/fs-src/fs.c:284
        rockchip-linux#17 0x7fb07a786fb3 in read_metadata ../../../src/fs-src/fs.c:593
        rockchip-linux#18 0x7fb07a78760e in ftrace_fs_source_init ../../../src/fs-src/fs.c:727
        rockchip-linux#19 0x7fb07d90c19c in add_component_with_init_method_data ../../../../src/lib/graph/graph.c:1048
        rockchip-linux#20 0x7fb07d90c87b in add_source_component_with_initialize_method_data ../../../../src/lib/graph/graph.c:1127
        rockchip-linux#21 0x7fb07d90c92a in bt_graph_add_source_component ../../../../src/lib/graph/graph.c:1152
        rockchip-linux#22 0x55db11aa632e in cmd_run_ctx_create_components_from_config_components ../../../src/cli/babeltrace2.c:2252
        rockchip-linux#23 0x55db11aa6fda in cmd_run_ctx_create_components ../../../src/cli/babeltrace2.c:2347
        rockchip-linux#24 0x55db11aa780c in cmd_run ../../../src/cli/babeltrace2.c:2461
        rockchip-linux#25 0x55db11aa8a7d in main ../../../src/cli/babeltrace2.c:2673
        rockchip-linux#26 0x7fb07d5460b2 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x270b2)

The token variable in the process_dynamic_array_len function is
allocated in the read_expect_type function, but is not freed before
calling the read_token function.

Free the token variable before calling read_token in order to plug the
leak.

Signed-off-by: Philippe Duplessis-Guindon <[email protected]>
Reviewed-by: Steven Rostedt (VMware) <[email protected]>
Link: https://lore.kernel.org/linux-trace-devel/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
friendlyarm referenced this issue in friendlyarm/kernel-rockchip Aug 31, 2020
commit 18c850f upstream.

There's long existed a lockdep splat because we open our bdev's under
the ->device_list_mutex at mount time, which acquires the bd_mutex.
Usually this goes unnoticed, but if you do loopback devices at all
suddenly the bd_mutex comes with a whole host of other dependencies,
which results in the splat when you mount a btrfs file system.

======================================================
WARNING: possible circular locking dependency detected
5.8.0-0.rc3.1.fc33.x86_64+debug #1 Not tainted
------------------------------------------------------
systemd-journal/509 is trying to acquire lock:
ffff970831f84db0 (&fs_info->reloc_mutex){+.+.}-{3:3}, at: btrfs_record_root_in_trans+0x44/0x70 [btrfs]

but task is already holding lock:
ffff97083144d598 (sb_pagefaults){.+.+}-{0:0}, at: btrfs_page_mkwrite+0x59/0x560 [btrfs]

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

 -> #6 (sb_pagefaults){.+.+}-{0:0}:
       __sb_start_write+0x13e/0x220
       btrfs_page_mkwrite+0x59/0x560 [btrfs]
       do_page_mkwrite+0x4f/0x130
       do_wp_page+0x3b0/0x4f0
       handle_mm_fault+0xf47/0x1850
       do_user_addr_fault+0x1fc/0x4b0
       exc_page_fault+0x88/0x300
       asm_exc_page_fault+0x1e/0x30

 -> #5 (&mm->mmap_lock#2){++++}-{3:3}:
       __might_fault+0x60/0x80
       _copy_from_user+0x20/0xb0
       get_sg_io_hdr+0x9a/0xb0
       scsi_cmd_ioctl+0x1ea/0x2f0
       cdrom_ioctl+0x3c/0x12b4
       sr_block_ioctl+0xa4/0xd0
       block_ioctl+0x3f/0x50
       ksys_ioctl+0x82/0xc0
       __x64_sys_ioctl+0x16/0x20
       do_syscall_64+0x52/0xb0
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

 -> #4 (&cd->lock){+.+.}-{3:3}:
       __mutex_lock+0x7b/0x820
       sr_block_open+0xa2/0x180
       __blkdev_get+0xdd/0x550
       blkdev_get+0x38/0x150
       do_dentry_open+0x16b/0x3e0
       path_openat+0x3c9/0xa00
       do_filp_open+0x75/0x100
       do_sys_openat2+0x8a/0x140
       __x64_sys_openat+0x46/0x70
       do_syscall_64+0x52/0xb0
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

 -> #3 (&bdev->bd_mutex){+.+.}-{3:3}:
       __mutex_lock+0x7b/0x820
       __blkdev_get+0x6a/0x550
       blkdev_get+0x85/0x150
       blkdev_get_by_path+0x2c/0x70
       btrfs_get_bdev_and_sb+0x1b/0xb0 [btrfs]
       open_fs_devices+0x88/0x240 [btrfs]
       btrfs_open_devices+0x92/0xa0 [btrfs]
       btrfs_mount_root+0x250/0x490 [btrfs]
       legacy_get_tree+0x30/0x50
       vfs_get_tree+0x28/0xc0
       vfs_kern_mount.part.0+0x71/0xb0
       btrfs_mount+0x119/0x380 [btrfs]
       legacy_get_tree+0x30/0x50
       vfs_get_tree+0x28/0xc0
       do_mount+0x8c6/0xca0
       __x64_sys_mount+0x8e/0xd0
       do_syscall_64+0x52/0xb0
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

 -> #2 (&fs_devs->device_list_mutex){+.+.}-{3:3}:
       __mutex_lock+0x7b/0x820
       btrfs_run_dev_stats+0x36/0x420 [btrfs]
       commit_cowonly_roots+0x91/0x2d0 [btrfs]
       btrfs_commit_transaction+0x4e6/0x9f0 [btrfs]
       btrfs_sync_file+0x38a/0x480 [btrfs]
       __x64_sys_fdatasync+0x47/0x80
       do_syscall_64+0x52/0xb0
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

 -> #1 (&fs_info->tree_log_mutex){+.+.}-{3:3}:
       __mutex_lock+0x7b/0x820
       btrfs_commit_transaction+0x48e/0x9f0 [btrfs]
       btrfs_sync_file+0x38a/0x480 [btrfs]
       __x64_sys_fdatasync+0x47/0x80
       do_syscall_64+0x52/0xb0
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

 -> #0 (&fs_info->reloc_mutex){+.+.}-{3:3}:
       __lock_acquire+0x1241/0x20c0
       lock_acquire+0xb0/0x400
       __mutex_lock+0x7b/0x820
       btrfs_record_root_in_trans+0x44/0x70 [btrfs]
       start_transaction+0xd2/0x500 [btrfs]
       btrfs_dirty_inode+0x44/0xd0 [btrfs]
       file_update_time+0xc6/0x120
       btrfs_page_mkwrite+0xda/0x560 [btrfs]
       do_page_mkwrite+0x4f/0x130
       do_wp_page+0x3b0/0x4f0
       handle_mm_fault+0xf47/0x1850
       do_user_addr_fault+0x1fc/0x4b0
       exc_page_fault+0x88/0x300
       asm_exc_page_fault+0x1e/0x30

other info that might help us debug this:

Chain exists of:
  &fs_info->reloc_mutex --> &mm->mmap_lock#2 --> sb_pagefaults

Possible unsafe locking scenario:

     CPU0                    CPU1
     ----                    ----
 lock(sb_pagefaults);
                             lock(&mm->mmap_lock#2);
                             lock(sb_pagefaults);
 lock(&fs_info->reloc_mutex);

 *** DEADLOCK ***

3 locks held by systemd-journal/509:
 #0: ffff97083bdec8b8 (&mm->mmap_lock#2){++++}-{3:3}, at: do_user_addr_fault+0x12e/0x4b0
 #1: ffff97083144d598 (sb_pagefaults){.+.+}-{0:0}, at: btrfs_page_mkwrite+0x59/0x560 [btrfs]
 #2: ffff97083144d6a8 (sb_internal){.+.+}-{0:0}, at: start_transaction+0x3f8/0x500 [btrfs]

stack backtrace:
CPU: 0 PID: 509 Comm: systemd-journal Not tainted 5.8.0-0.rc3.1.fc33.x86_64+debug #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
Call Trace:
 dump_stack+0x92/0xc8
 check_noncircular+0x134/0x150
 __lock_acquire+0x1241/0x20c0
 lock_acquire+0xb0/0x400
 ? btrfs_record_root_in_trans+0x44/0x70 [btrfs]
 ? lock_acquire+0xb0/0x400
 ? btrfs_record_root_in_trans+0x44/0x70 [btrfs]
 __mutex_lock+0x7b/0x820
 ? btrfs_record_root_in_trans+0x44/0x70 [btrfs]
 ? kvm_sched_clock_read+0x14/0x30
 ? sched_clock+0x5/0x10
 ? sched_clock_cpu+0xc/0xb0
 btrfs_record_root_in_trans+0x44/0x70 [btrfs]
 start_transaction+0xd2/0x500 [btrfs]
 btrfs_dirty_inode+0x44/0xd0 [btrfs]
 file_update_time+0xc6/0x120
 btrfs_page_mkwrite+0xda/0x560 [btrfs]
 ? sched_clock+0x5/0x10
 do_page_mkwrite+0x4f/0x130
 do_wp_page+0x3b0/0x4f0
 handle_mm_fault+0xf47/0x1850
 do_user_addr_fault+0x1fc/0x4b0
 exc_page_fault+0x88/0x300
 ? asm_exc_page_fault+0x8/0x30
 asm_exc_page_fault+0x1e/0x30
RIP: 0033:0x7fa3972fdbfe
Code: Bad RIP value.

Fix this by not holding the ->device_list_mutex at this point.  The
device_list_mutex exists to protect us from modifying the device list
while the file system is running.

However it can also be modified by doing a scan on a device.  But this
action is specifically protected by the uuid_mutex, which we are holding
here.  We cannot race with opening at this point because we have the
->s_mount lock held during the mount.  Not having the
->device_list_mutex here is perfectly safe as we're not going to change
the devices at this point.

CC: [email protected] # 4.19+
Signed-off-by: Josef Bacik <[email protected]>
Reviewed-by: David Sterba <[email protected]>
[ add some comments ]
Signed-off-by: David Sterba <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
AaronDewes pushed a commit to AaronDewes/kernel that referenced this issue Sep 29, 2020
[ Upstream commit d26383d ]

The following leaks were detected by ASAN:

  Indirect leak of 360 byte(s) in 9 object(s) allocated from:
    #0 0x7fecc305180e in calloc (/lib/x86_64-linux-gnu/libasan.so.5+0x10780e)
    rockchip-linux#1 0x560578f6dce5 in perf_pmu__new_format util/pmu.c:1333
    rockchip-linux#2 0x560578f752fc in perf_pmu_parse util/pmu.y:59
    rockchip-linux#3 0x560578f6a8b7 in perf_pmu__format_parse util/pmu.c:73
    rockchip-linux#4 0x560578e07045 in test__pmu tests/pmu.c:155
    rockchip-linux#5 0x560578de109b in run_test tests/builtin-test.c:410
    rockchip-linux#6 0x560578de109b in test_and_print tests/builtin-test.c:440
    rockchip-linux#7 0x560578de401a in __cmd_test tests/builtin-test.c:661
    rockchip-linux#8 0x560578de401a in cmd_test tests/builtin-test.c:807
    rockchip-linux#9 0x560578e49354 in run_builtin /home/namhyung/project/linux/tools/perf/perf.c:312
    rockchip-linux#10 0x560578ce71a8 in handle_internal_command /home/namhyung/project/linux/tools/perf/perf.c:364
    rockchip-linux#11 0x560578ce71a8 in run_argv /home/namhyung/project/linux/tools/perf/perf.c:408
    rockchip-linux#12 0x560578ce71a8 in main /home/namhyung/project/linux/tools/perf/perf.c:538
    rockchip-linux#13 0x7fecc2b7acc9 in __libc_start_main ../csu/libc-start.c:308

Fixes: cff7f95 ("perf tests: Move pmu tests into separate object")
Signed-off-by: Namhyung Kim <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Ian Rogers <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
rkchrome pushed a commit that referenced this issue Oct 10, 2020
[ Upstream commit 266150c ]

Realloc of size zero is a free not an error, avoid this causing a double
free. Caught by clang's address sanitizer:

==2634==ERROR: AddressSanitizer: attempting double-free on 0x6020000015f0 in thread T0:
    #0 0x5649659297fd in free llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:123:3
    #1 0x5649659e9251 in __zfree tools/lib/zalloc.c:13:2
    #2 0x564965c0f92c in mem2node__exit tools/perf/util/mem2node.c:114:2
    #3 0x564965a08b4c in perf_c2c__report tools/perf/builtin-c2c.c:2867:2
    #4 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
    #5 0x564965944348 in run_builtin tools/perf/perf.c:312:11
    #6 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
    #7 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
    #8 0x564965942e41 in main tools/perf/perf.c:538:3

0x6020000015f0 is located 0 bytes inside of 1-byte region [0x6020000015f0,0x6020000015f1)
freed by thread T0 here:
    #0 0x564965929da3 in realloc third_party/llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:164:3
    #1 0x564965c0f55e in mem2node__init tools/perf/util/mem2node.c:97:16
    #2 0x564965a08956 in perf_c2c__report tools/perf/builtin-c2c.c:2803:8
    #3 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
    #4 0x564965944348 in run_builtin tools/perf/perf.c:312:11
    #5 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
    #6 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
    #7 0x564965942e41 in main tools/perf/perf.c:538:3

previously allocated by thread T0 here:
    #0 0x564965929c42 in calloc third_party/llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:154:3
    #1 0x5649659e9220 in zalloc tools/lib/zalloc.c:8:9
    #2 0x564965c0f32d in mem2node__init tools/perf/util/mem2node.c:61:12
    #3 0x564965a08956 in perf_c2c__report tools/perf/builtin-c2c.c:2803:8
    #4 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
    #5 0x564965944348 in run_builtin tools/perf/perf.c:312:11
    #6 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
    #7 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
    #8 0x564965942e41 in main tools/perf/perf.c:538:3

v2: add a WARN_ON_ONCE when the free condition arises.

Signed-off-by: Ian Rogers <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: [email protected]
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
rkchrome pushed a commit that referenced this issue Nov 3, 2020
[ Upstream commit 6617dfd ]

Commit 4fc427e ("ipv6_route_seq_next should increase position index")
tried to fix the issue where seq_file pos is not increased
if a NULL element is returned with seq_ops->next(). See bug
  https://bugzilla.kernel.org/show_bug.cgi?id=206283
The commit effectively does:
  - increase pos for all seq_ops->start()
  - increase pos for all seq_ops->next()

For ipv6_route, increasing pos for all seq_ops->next() is correct.
But increasing pos for seq_ops->start() is not correct
since pos is used to determine how many items to skip during
seq_ops->start():
  iter->skip = *pos;
seq_ops->start() just fetches the *current* pos item.
The item can be skipped only after seq_ops->show() which essentially
is the beginning of seq_ops->next().

For example, I have 7 ipv6 route entries,
  root@arch-fb-vm1:~/net-next dd if=/proc/net/ipv6_route bs=4096
  00000000000000000000000000000000 40 00000000000000000000000000000000 00 00000000000000000000000000000000 00000400 00000001 00000000 00000001     eth0
  fe800000000000000000000000000000 40 00000000000000000000000000000000 00 00000000000000000000000000000000 00000100 00000001 00000000 00000001     eth0
  00000000000000000000000000000000 00 00000000000000000000000000000000 00 00000000000000000000000000000000 ffffffff 00000001 00000000 00200200       lo
  00000000000000000000000000000001 80 00000000000000000000000000000000 00 00000000000000000000000000000000 00000000 00000003 00000000 80200001       lo
  fe800000000000002050e3fffebd3be8 80 00000000000000000000000000000000 00 00000000000000000000000000000000 00000000 00000002 00000000 80200001     eth0
  ff000000000000000000000000000000 08 00000000000000000000000000000000 00 00000000000000000000000000000000 00000100 00000004 00000000 00000001     eth0
  00000000000000000000000000000000 00 00000000000000000000000000000000 00 00000000000000000000000000000000 ffffffff 00000001 00000000 00200200       lo
  0+1 records in
  0+1 records out
  1050 bytes (1.0 kB, 1.0 KiB) copied, 0.00707908 s, 148 kB/s
  root@arch-fb-vm1:~/net-next

In the above, I specify buffer size 4096, so all records can be returned
to user space with a single trip to the kernel.

If I use buffer size 128, since each record size is 149, internally
kernel seq_read() will read 149 into its internal buffer and return the data
to user space in two read() syscalls. Then user read() syscall will trigger
next seq_ops->start(). Since the current implementation increased pos even
for seq_ops->start(), it will skip record #2, #4 and #6, assuming the first
record is #1.

  root@arch-fb-vm1:~/net-next dd if=/proc/net/ipv6_route bs=128
  00000000000000000000000000000000 40 00000000000000000000000000000000 00 00000000000000000000000000000000 00000400 00000001 00000000 00000001     eth0
  00000000000000000000000000000000 00 00000000000000000000000000000000 00 00000000000000000000000000000000 ffffffff 00000001 00000000 00200200       lo
  fe800000000000002050e3fffebd3be8 80 00000000000000000000000000000000 00 00000000000000000000000000000000 00000000 00000002 00000000 80200001     eth0
  00000000000000000000000000000000 00 00000000000000000000000000000000 00 00000000000000000000000000000000 ffffffff 00000001 00000000 00200200       lo
4+1 records in
4+1 records out
600 bytes copied, 0.00127758 s, 470 kB/s

To fix the problem, create a fake pos pointer so seq_ops->start()
won't actually increase seq_file pos. With this fix, the
above `dd` command with `bs=128` will show correct result.

Fixes: 4fc427e ("ipv6_route_seq_next should increase position index")
Cc: Alexei Starovoitov <[email protected]>
Suggested-by: Vasily Averin <[email protected]>
Reviewed-by: Vasily Averin <[email protected]>
Signed-off-by: Yonghong Song <[email protected]>
Acked-by: Martin KaFai Lau <[email protected]>
Acked-by: Andrii Nakryiko <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
friendlyarm referenced this issue in friendlyarm/kernel-rockchip Nov 17, 2020
[ Upstream commit 266150c ]

Realloc of size zero is a free not an error, avoid this causing a double
free. Caught by clang's address sanitizer:

==2634==ERROR: AddressSanitizer: attempting double-free on 0x6020000015f0 in thread T0:
    #0 0x5649659297fd in free llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:123:3
    #1 0x5649659e9251 in __zfree tools/lib/zalloc.c:13:2
    #2 0x564965c0f92c in mem2node__exit tools/perf/util/mem2node.c:114:2
    #3 0x564965a08b4c in perf_c2c__report tools/perf/builtin-c2c.c:2867:2
    #4 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
    #5 0x564965944348 in run_builtin tools/perf/perf.c:312:11
    #6 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
    #7 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
    #8 0x564965942e41 in main tools/perf/perf.c:538:3

0x6020000015f0 is located 0 bytes inside of 1-byte region [0x6020000015f0,0x6020000015f1)
freed by thread T0 here:
    #0 0x564965929da3 in realloc third_party/llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:164:3
    #1 0x564965c0f55e in mem2node__init tools/perf/util/mem2node.c:97:16
    #2 0x564965a08956 in perf_c2c__report tools/perf/builtin-c2c.c:2803:8
    #3 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
    #4 0x564965944348 in run_builtin tools/perf/perf.c:312:11
    #5 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
    #6 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
    #7 0x564965942e41 in main tools/perf/perf.c:538:3

previously allocated by thread T0 here:
    #0 0x564965929c42 in calloc third_party/llvm/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:154:3
    #1 0x5649659e9220 in zalloc tools/lib/zalloc.c:8:9
    #2 0x564965c0f32d in mem2node__init tools/perf/util/mem2node.c:61:12
    #3 0x564965a08956 in perf_c2c__report tools/perf/builtin-c2c.c:2803:8
    #4 0x564965a0616a in cmd_c2c tools/perf/builtin-c2c.c:2989:10
    #5 0x564965944348 in run_builtin tools/perf/perf.c:312:11
    #6 0x564965943235 in handle_internal_command tools/perf/perf.c:364:8
    #7 0x5649659440c4 in run_argv tools/perf/perf.c:408:2
    #8 0x564965942e41 in main tools/perf/perf.c:538:3

v2: add a WARN_ON_ONCE when the free condition arises.

Signed-off-by: Ian Rogers <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: [email protected]
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
friendlyarm referenced this issue in friendlyarm/kernel-rockchip Nov 17, 2020
[ Upstream commit 6617dfd ]

Commit 4fc427e ("ipv6_route_seq_next should increase position index")
tried to fix the issue where seq_file pos is not increased
if a NULL element is returned with seq_ops->next(). See bug
  https://bugzilla.kernel.org/show_bug.cgi?id=206283
The commit effectively does:
  - increase pos for all seq_ops->start()
  - increase pos for all seq_ops->next()

For ipv6_route, increasing pos for all seq_ops->next() is correct.
But increasing pos for seq_ops->start() is not correct
since pos is used to determine how many items to skip during
seq_ops->start():
  iter->skip = *pos;
seq_ops->start() just fetches the *current* pos item.
The item can be skipped only after seq_ops->show() which essentially
is the beginning of seq_ops->next().

For example, I have 7 ipv6 route entries,
  root@arch-fb-vm1:~/net-next dd if=/proc/net/ipv6_route bs=4096
  00000000000000000000000000000000 40 00000000000000000000000000000000 00 00000000000000000000000000000000 00000400 00000001 00000000 00000001     eth0
  fe800000000000000000000000000000 40 00000000000000000000000000000000 00 00000000000000000000000000000000 00000100 00000001 00000000 00000001     eth0
  00000000000000000000000000000000 00 00000000000000000000000000000000 00 00000000000000000000000000000000 ffffffff 00000001 00000000 00200200       lo
  00000000000000000000000000000001 80 00000000000000000000000000000000 00 00000000000000000000000000000000 00000000 00000003 00000000 80200001       lo
  fe800000000000002050e3fffebd3be8 80 00000000000000000000000000000000 00 00000000000000000000000000000000 00000000 00000002 00000000 80200001     eth0
  ff000000000000000000000000000000 08 00000000000000000000000000000000 00 00000000000000000000000000000000 00000100 00000004 00000000 00000001     eth0
  00000000000000000000000000000000 00 00000000000000000000000000000000 00 00000000000000000000000000000000 ffffffff 00000001 00000000 00200200       lo
  0+1 records in
  0+1 records out
  1050 bytes (1.0 kB, 1.0 KiB) copied, 0.00707908 s, 148 kB/s
  root@arch-fb-vm1:~/net-next

In the above, I specify buffer size 4096, so all records can be returned
to user space with a single trip to the kernel.

If I use buffer size 128, since each record size is 149, internally
kernel seq_read() will read 149 into its internal buffer and return the data
to user space in two read() syscalls. Then user read() syscall will trigger
next seq_ops->start(). Since the current implementation increased pos even
for seq_ops->start(), it will skip record #2, #4 and #6, assuming the first
record is #1.

  root@arch-fb-vm1:~/net-next dd if=/proc/net/ipv6_route bs=128
  00000000000000000000000000000000 40 00000000000000000000000000000000 00 00000000000000000000000000000000 00000400 00000001 00000000 00000001     eth0
  00000000000000000000000000000000 00 00000000000000000000000000000000 00 00000000000000000000000000000000 ffffffff 00000001 00000000 00200200       lo
  fe800000000000002050e3fffebd3be8 80 00000000000000000000000000000000 00 00000000000000000000000000000000 00000000 00000002 00000000 80200001     eth0
  00000000000000000000000000000000 00 00000000000000000000000000000000 00 00000000000000000000000000000000 ffffffff 00000001 00000000 00200200       lo
4+1 records in
4+1 records out
600 bytes copied, 0.00127758 s, 470 kB/s

To fix the problem, create a fake pos pointer so seq_ops->start()
won't actually increase seq_file pos. With this fix, the
above `dd` command with `bs=128` will show correct result.

Fixes: 4fc427e ("ipv6_route_seq_next should increase position index")
Cc: Alexei Starovoitov <[email protected]>
Suggested-by: Vasily Averin <[email protected]>
Reviewed-by: Vasily Averin <[email protected]>
Signed-off-by: Yonghong Song <[email protected]>
Acked-by: Martin KaFai Lau <[email protected]>
Acked-by: Andrii Nakryiko <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
friendlyarm referenced this issue in friendlyarm/kernel-rockchip Nov 17, 2020
commit 66d204a upstream.

Very sporadically I had test case btrfs/069 from fstests hanging (for
years, it is not a recent regression), with the following traces in
dmesg/syslog:

  [162301.160628] BTRFS info (device sdc): dev_replace from /dev/sdd (devid 2) to /dev/sdg started
  [162301.181196] BTRFS info (device sdc): scrub: finished on devid 4 with status: 0
  [162301.287162] BTRFS info (device sdc): dev_replace from /dev/sdd (devid 2) to /dev/sdg finished
  [162513.513792] INFO: task btrfs-transacti:1356167 blocked for more than 120 seconds.
  [162513.514318]       Not tainted 5.9.0-rc6-btrfs-next-69 #1
  [162513.514522] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [162513.514747] task:btrfs-transacti state:D stack:    0 pid:1356167 ppid:     2 flags:0x00004000
  [162513.514751] Call Trace:
  [162513.514761]  __schedule+0x5ce/0xd00
  [162513.514765]  ? _raw_spin_unlock_irqrestore+0x3c/0x60
  [162513.514771]  schedule+0x46/0xf0
  [162513.514844]  wait_current_trans+0xde/0x140 [btrfs]
  [162513.514850]  ? finish_wait+0x90/0x90
  [162513.514864]  start_transaction+0x37c/0x5f0 [btrfs]
  [162513.514879]  transaction_kthread+0xa4/0x170 [btrfs]
  [162513.514891]  ? btrfs_cleanup_transaction+0x660/0x660 [btrfs]
  [162513.514894]  kthread+0x153/0x170
  [162513.514897]  ? kthread_stop+0x2c0/0x2c0
  [162513.514902]  ret_from_fork+0x22/0x30
  [162513.514916] INFO: task fsstress:1356184 blocked for more than 120 seconds.
  [162513.515192]       Not tainted 5.9.0-rc6-btrfs-next-69 #1
  [162513.515431] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [162513.515680] task:fsstress        state:D stack:    0 pid:1356184 ppid:1356177 flags:0x00004000
  [162513.515682] Call Trace:
  [162513.515688]  __schedule+0x5ce/0xd00
  [162513.515691]  ? _raw_spin_unlock_irqrestore+0x3c/0x60
  [162513.515697]  schedule+0x46/0xf0
  [162513.515712]  wait_current_trans+0xde/0x140 [btrfs]
  [162513.515716]  ? finish_wait+0x90/0x90
  [162513.515729]  start_transaction+0x37c/0x5f0 [btrfs]
  [162513.515743]  btrfs_attach_transaction_barrier+0x1f/0x50 [btrfs]
  [162513.515753]  btrfs_sync_fs+0x61/0x1c0 [btrfs]
  [162513.515758]  ? __ia32_sys_fdatasync+0x20/0x20
  [162513.515761]  iterate_supers+0x87/0xf0
  [162513.515765]  ksys_sync+0x60/0xb0
  [162513.515768]  __do_sys_sync+0xa/0x10
  [162513.515771]  do_syscall_64+0x33/0x80
  [162513.515774]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
  [162513.515781] RIP: 0033:0x7f5238f50bd7
  [162513.515782] Code: Bad RIP value.
  [162513.515784] RSP: 002b:00007fff67b978e8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a2
  [162513.515786] RAX: ffffffffffffffda RBX: 000055b1fad2c560 RCX: 00007f5238f50bd7
  [162513.515788] RDX: 00000000ffffffff RSI: 000000000daf0e74 RDI: 000000000000003a
  [162513.515789] RBP: 0000000000000032 R08: 000000000000000a R09: 00007f5239019be0
  [162513.515791] R10: fffffffffffff24f R11: 0000000000000206 R12: 000000000000003a
  [162513.515792] R13: 00007fff67b97950 R14: 00007fff67b97906 R15: 000055b1fad1a340
  [162513.515804] INFO: task fsstress:1356185 blocked for more than 120 seconds.
  [162513.516064]       Not tainted 5.9.0-rc6-btrfs-next-69 #1
  [162513.516329] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [162513.516617] task:fsstress        state:D stack:    0 pid:1356185 ppid:1356177 flags:0x00000000
  [162513.516620] Call Trace:
  [162513.516625]  __schedule+0x5ce/0xd00
  [162513.516628]  ? _raw_spin_unlock_irqrestore+0x3c/0x60
  [162513.516634]  schedule+0x46/0xf0
  [162513.516647]  wait_current_trans+0xde/0x140 [btrfs]
  [162513.516650]  ? finish_wait+0x90/0x90
  [162513.516662]  start_transaction+0x4d7/0x5f0 [btrfs]
  [162513.516679]  btrfs_setxattr_trans+0x3c/0x100 [btrfs]
  [162513.516686]  __vfs_setxattr+0x66/0x80
  [162513.516691]  __vfs_setxattr_noperm+0x70/0x200
  [162513.516697]  vfs_setxattr+0x6b/0x120
  [162513.516703]  setxattr+0x125/0x240
  [162513.516709]  ? lock_acquire+0xb1/0x480
  [162513.516712]  ? mnt_want_write+0x20/0x50
  [162513.516721]  ? rcu_read_lock_any_held+0x8e/0xb0
  [162513.516723]  ? preempt_count_add+0x49/0xa0
  [162513.516725]  ? __sb_start_write+0x19b/0x290
  [162513.516727]  ? preempt_count_add+0x49/0xa0
  [162513.516732]  path_setxattr+0xba/0xd0
  [162513.516739]  __x64_sys_setxattr+0x27/0x30
  [162513.516741]  do_syscall_64+0x33/0x80
  [162513.516743]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
  [162513.516745] RIP: 0033:0x7f5238f56d5a
  [162513.516746] Code: Bad RIP value.
  [162513.516748] RSP: 002b:00007fff67b97868 EFLAGS: 00000202 ORIG_RAX: 00000000000000bc
  [162513.516750] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f5238f56d5a
  [162513.516751] RDX: 000055b1fbb0d5a0 RSI: 00007fff67b978a0 RDI: 000055b1fbb0d470
  [162513.516753] RBP: 000055b1fbb0d5a0 R08: 0000000000000001 R09: 00007fff67b97700
  [162513.516754] R10: 0000000000000004 R11: 0000000000000202 R12: 0000000000000004
  [162513.516756] R13: 0000000000000024 R14: 0000000000000001 R15: 00007fff67b978a0
  [162513.516767] INFO: task fsstress:1356196 blocked for more than 120 seconds.
  [162513.517064]       Not tainted 5.9.0-rc6-btrfs-next-69 #1
  [162513.517365] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [162513.517763] task:fsstress        state:D stack:    0 pid:1356196 ppid:1356177 flags:0x00004000
  [162513.517780] Call Trace:
  [162513.517786]  __schedule+0x5ce/0xd00
  [162513.517789]  ? _raw_spin_unlock_irqrestore+0x3c/0x60
  [162513.517796]  schedule+0x46/0xf0
  [162513.517810]  wait_current_trans+0xde/0x140 [btrfs]
  [162513.517814]  ? finish_wait+0x90/0x90
  [162513.517829]  start_transaction+0x37c/0x5f0 [btrfs]
  [162513.517845]  btrfs_attach_transaction_barrier+0x1f/0x50 [btrfs]
  [162513.517857]  btrfs_sync_fs+0x61/0x1c0 [btrfs]
  [162513.517862]  ? __ia32_sys_fdatasync+0x20/0x20
  [162513.517865]  iterate_supers+0x87/0xf0
  [162513.517869]  ksys_sync+0x60/0xb0
  [162513.517872]  __do_sys_sync+0xa/0x10
  [162513.517875]  do_syscall_64+0x33/0x80
  [162513.517878]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
  [162513.517881] RIP: 0033:0x7f5238f50bd7
  [162513.517883] Code: Bad RIP value.
  [162513.517885] RSP: 002b:00007fff67b978e8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a2
  [162513.517887] RAX: ffffffffffffffda RBX: 000055b1fad2c560 RCX: 00007f5238f50bd7
  [162513.517889] RDX: 0000000000000000 RSI: 000000007660add2 RDI: 0000000000000053
  [162513.517891] RBP: 0000000000000032 R08: 0000000000000067 R09: 00007f5239019be0
  [162513.517893] R10: fffffffffffff24f R11: 0000000000000206 R12: 0000000000000053
  [162513.517895] R13: 00007fff67b97950 R14: 00007fff67b97906 R15: 000055b1fad1a340
  [162513.517908] INFO: task fsstress:1356197 blocked for more than 120 seconds.
  [162513.518298]       Not tainted 5.9.0-rc6-btrfs-next-69 #1
  [162513.518672] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [162513.519157] task:fsstress        state:D stack:    0 pid:1356197 ppid:1356177 flags:0x00000000
  [162513.519160] Call Trace:
  [162513.519165]  __schedule+0x5ce/0xd00
  [162513.519168]  ? _raw_spin_unlock_irqrestore+0x3c/0x60
  [162513.519174]  schedule+0x46/0xf0
  [162513.519190]  wait_current_trans+0xde/0x140 [btrfs]
  [162513.519193]  ? finish_wait+0x90/0x90
  [162513.519206]  start_transaction+0x4d7/0x5f0 [btrfs]
  [162513.519222]  btrfs_create+0x57/0x200 [btrfs]
  [162513.519230]  lookup_open+0x522/0x650
  [162513.519246]  path_openat+0x2b8/0xa50
  [162513.519270]  do_filp_open+0x91/0x100
  [162513.519275]  ? find_held_lock+0x32/0x90
  [162513.519280]  ? lock_acquired+0x33b/0x470
  [162513.519285]  ? do_raw_spin_unlock+0x4b/0xc0
  [162513.519287]  ? _raw_spin_unlock+0x29/0x40
  [162513.519295]  do_sys_openat2+0x20d/0x2d0
  [162513.519300]  do_sys_open+0x44/0x80
  [162513.519304]  do_syscall_64+0x33/0x80
  [162513.519307]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
  [162513.519309] RIP: 0033:0x7f5238f4a903
  [162513.519310] Code: Bad RIP value.
  [162513.519312] RSP: 002b:00007fff67b97758 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
  [162513.519314] RAX: ffffffffffffffda RBX: 00000000ffffffff RCX: 00007f5238f4a903
  [162513.519316] RDX: 0000000000000000 RSI: 00000000000001b6 RDI: 000055b1fbb0d470
  [162513.519317] RBP: 00007fff67b978c0 R08: 0000000000000001 R09: 0000000000000002
  [162513.519319] R10: 00007fff67b974f7 R11: 0000000000000246 R12: 0000000000000013
  [162513.519320] R13: 00000000000001b6 R14: 00007fff67b97906 R15: 000055b1fad1c620
  [162513.519332] INFO: task btrfs:1356211 blocked for more than 120 seconds.
  [162513.519727]       Not tainted 5.9.0-rc6-btrfs-next-69 #1
  [162513.520115] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [162513.520508] task:btrfs           state:D stack:    0 pid:1356211 ppid:1356178 flags:0x00004002
  [162513.520511] Call Trace:
  [162513.520516]  __schedule+0x5ce/0xd00
  [162513.520519]  ? _raw_spin_unlock_irqrestore+0x3c/0x60
  [162513.520525]  schedule+0x46/0xf0
  [162513.520544]  btrfs_scrub_pause+0x11f/0x180 [btrfs]
  [162513.520548]  ? finish_wait+0x90/0x90
  [162513.520562]  btrfs_commit_transaction+0x45a/0xc30 [btrfs]
  [162513.520574]  ? start_transaction+0xe0/0x5f0 [btrfs]
  [162513.520596]  btrfs_dev_replace_finishing+0x6d8/0x711 [btrfs]
  [162513.520619]  btrfs_dev_replace_by_ioctl.cold+0x1cc/0x1fd [btrfs]
  [162513.520639]  btrfs_ioctl+0x2a25/0x36f0 [btrfs]
  [162513.520643]  ? do_sigaction+0xf3/0x240
  [162513.520645]  ? find_held_lock+0x32/0x90
  [162513.520648]  ? do_sigaction+0xf3/0x240
  [162513.520651]  ? lock_acquired+0x33b/0x470
  [162513.520655]  ? _raw_spin_unlock_irq+0x24/0x50
  [162513.520657]  ? lockdep_hardirqs_on+0x7d/0x100
  [162513.520660]  ? _raw_spin_unlock_irq+0x35/0x50
  [162513.520662]  ? do_sigaction+0xf3/0x240
  [162513.520671]  ? __x64_sys_ioctl+0x83/0xb0
  [162513.520672]  __x64_sys_ioctl+0x83/0xb0
  [162513.520677]  do_syscall_64+0x33/0x80
  [162513.520679]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
  [162513.520681] RIP: 0033:0x7fc3cd307d87
  [162513.520682] Code: Bad RIP value.
  [162513.520684] RSP: 002b:00007ffe30a56bb8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
  [162513.520686] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007fc3cd307d87
  [162513.520687] RDX: 00007ffe30a57a30 RSI: 00000000ca289435 RDI: 0000000000000003
  [162513.520689] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
  [162513.520690] R10: 0000000000000008 R11: 0000000000000202 R12: 0000000000000003
  [162513.520692] R13: 0000557323a212e0 R14: 00007ffe30a5a520 R15: 0000000000000001
  [162513.520703]
		  Showing all locks held in the system:
  [162513.520712] 1 lock held by khungtaskd/54:
  [162513.520713]  #0: ffffffffb40a91a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x15/0x197
  [162513.520728] 1 lock held by in:imklog/596:
  [162513.520729]  #0: ffff8f3f0d781400 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x4d/0x60
  [162513.520782] 1 lock held by btrfs-transacti/1356167:
  [162513.520784]  #0: ffff8f3d810cc848 (&fs_info->transaction_kthread_mutex){+.+.}-{3:3}, at: transaction_kthread+0x4a/0x170 [btrfs]
  [162513.520798] 1 lock held by btrfs/1356190:
  [162513.520800]  #0: ffff8f3d57644470 (sb_writers#15){.+.+}-{0:0}, at: mnt_want_write_file+0x22/0x60
  [162513.520805] 1 lock held by fsstress/1356184:
  [162513.520806]  #0: ffff8f3d576440e8 (&type->s_umount_key#62){++++}-{3:3}, at: iterate_supers+0x6f/0xf0
  [162513.520811] 3 locks held by fsstress/1356185:
  [162513.520812]  #0: ffff8f3d57644470 (sb_writers#15){.+.+}-{0:0}, at: mnt_want_write+0x20/0x50
  [162513.520815]  #1: ffff8f3d80a650b8 (&type->i_mutex_dir_key#10){++++}-{3:3}, at: vfs_setxattr+0x50/0x120
  [162513.520820]  #2: ffff8f3d57644690 (sb_internal#2){.+.+}-{0:0}, at: start_transaction+0x40e/0x5f0 [btrfs]
  [162513.520833] 1 lock held by fsstress/1356196:
  [162513.520834]  #0: ffff8f3d576440e8 (&type->s_umount_key#62){++++}-{3:3}, at: iterate_supers+0x6f/0xf0
  [162513.520838] 3 locks held by fsstress/1356197:
  [162513.520839]  #0: ffff8f3d57644470 (sb_writers#15){.+.+}-{0:0}, at: mnt_want_write+0x20/0x50
  [162513.520843]  #1: ffff8f3d506465e8 (&type->i_mutex_dir_key#10){++++}-{3:3}, at: path_openat+0x2a7/0xa50
  [162513.520846]  #2: ffff8f3d57644690 (sb_internal#2){.+.+}-{0:0}, at: start_transaction+0x40e/0x5f0 [btrfs]
  [162513.520858] 2 locks held by btrfs/1356211:
  [162513.520859]  #0: ffff8f3d810cde30 (&fs_info->dev_replace.lock_finishing_cancel_unmount){+.+.}-{3:3}, at: btrfs_dev_replace_finishing+0x52/0x711 [btrfs]
  [162513.520877]  #1: ffff8f3d57644690 (sb_internal#2){.+.+}-{0:0}, at: start_transaction+0x40e/0x5f0 [btrfs]

This was weird because the stack traces show that a transaction commit,
triggered by a device replace operation, is blocking trying to pause any
running scrubs but there are no stack traces of blocked tasks doing a
scrub.

After poking around with drgn, I noticed there was a scrub task that was
constantly running and blocking for shorts periods of time:

  >>> t = find_task(prog, 1356190)
  >>> prog.stack_trace(t)
  #0  __schedule+0x5ce/0xcfc
  #1  schedule+0x46/0xe4
  #2  schedule_timeout+0x1df/0x475
  #3  btrfs_reada_wait+0xda/0x132
  #4  scrub_stripe+0x2a8/0x112f
  #5  scrub_chunk+0xcd/0x134
  #6  scrub_enumerate_chunks+0x29e/0x5ee
  #7  btrfs_scrub_dev+0x2d5/0x91b
  #8  btrfs_ioctl+0x7f5/0x36e7
  rockchip-linux#9  __x64_sys_ioctl+0x83/0xb0
  rockchip-linux#10 do_syscall_64+0x33/0x77
  rockchip-linux#11 entry_SYSCALL_64+0x7c/0x156

Which corresponds to:

int btrfs_reada_wait(void *handle)
{
    struct reada_control *rc = handle;
    struct btrfs_fs_info *fs_info = rc->fs_info;

    while (atomic_read(&rc->elems)) {
        if (!atomic_read(&fs_info->reada_works_cnt))
            reada_start_machine(fs_info);
        wait_event_timeout(rc->wait, atomic_read(&rc->elems) == 0,
                          (HZ + 9) / 10);
    }
(...)

So the counter "rc->elems" was set to 1 and never decreased to 0, causing
the scrub task to loop forever in that function. Then I used the following
script for drgn to check the readahead requests:

  $ cat dump_reada.py
  import sys
  import drgn
  from drgn import NULL, Object, cast, container_of, execscript, \
      reinterpret, sizeof
  from drgn.helpers.linux import *

  mnt_path = b"/home/fdmanana/btrfs-tests/scratch_1"

  mnt = None
  for mnt in for_each_mount(prog, dst = mnt_path):
      pass

  if mnt is None:
      sys.stderr.write(f'Error: mount point {mnt_path} not found\n')
      sys.exit(1)

  fs_info = cast('struct btrfs_fs_info *', mnt.mnt.mnt_sb.s_fs_info)

  def dump_re(re):
      nzones = re.nzones.value_()
      print(f're at {hex(re.value_())}')
      print(f'\t logical {re.logical.value_()}')
      print(f'\t refcnt {re.refcnt.value_()}')
      print(f'\t nzones {nzones}')
      for i in range(nzones):
          dev = re.zones[i].device
          name = dev.name.str.string_()
          print(f'\t\t dev id {dev.devid.value_()} name {name}')
      print()

  for _, e in radix_tree_for_each(fs_info.reada_tree):
      re = cast('struct reada_extent *', e)
      dump_re(re)

  $ drgn dump_reada.py
  re at 0xffff8f3da9d25ad8
          logical 38928384
          refcnt 1
          nzones 1
                 dev id 0 name b'/dev/sdd'
  $

So there was one readahead extent with a single zone corresponding to the
source device of that last device replace operation logged in dmesg/syslog.
Also the ID of that zone's device was 0 which is a special value set in
the source device of a device replace operation when the operation finishes
(constant BTRFS_DEV_REPLACE_DEVID set at btrfs_dev_replace_finishing()),
confirming again that device /dev/sdd was the source of a device replace
operation.

Normally there should be as many zones in the readahead extent as there are
devices, and I wasn't expecting the extent to be in a block group with a
'single' profile, so I went and confirmed with the following drgn script
that there weren't any single profile block groups:

  $ cat dump_block_groups.py
  import sys
  import drgn
  from drgn import NULL, Object, cast, container_of, execscript, \
      reinterpret, sizeof
  from drgn.helpers.linux import *

  mnt_path = b"/home/fdmanana/btrfs-tests/scratch_1"

  mnt = None
  for mnt in for_each_mount(prog, dst = mnt_path):
      pass

  if mnt is None:
      sys.stderr.write(f'Error: mount point {mnt_path} not found\n')
      sys.exit(1)

  fs_info = cast('struct btrfs_fs_info *', mnt.mnt.mnt_sb.s_fs_info)

  BTRFS_BLOCK_GROUP_DATA = (1 << 0)
  BTRFS_BLOCK_GROUP_SYSTEM = (1 << 1)
  BTRFS_BLOCK_GROUP_METADATA = (1 << 2)
  BTRFS_BLOCK_GROUP_RAID0 = (1 << 3)
  BTRFS_BLOCK_GROUP_RAID1 = (1 << 4)
  BTRFS_BLOCK_GROUP_DUP = (1 << 5)
  BTRFS_BLOCK_GROUP_RAID10 = (1 << 6)
  BTRFS_BLOCK_GROUP_RAID5 = (1 << 7)
  BTRFS_BLOCK_GROUP_RAID6 = (1 << 8)
  BTRFS_BLOCK_GROUP_RAID1C3 = (1 << 9)
  BTRFS_BLOCK_GROUP_RAID1C4 = (1 << 10)

  def bg_flags_string(bg):
      flags = bg.flags.value_()
      ret = ''
      if flags & BTRFS_BLOCK_GROUP_DATA:
          ret = 'data'
      if flags & BTRFS_BLOCK_GROUP_METADATA:
          if len(ret) > 0:
              ret += '|'
          ret += 'meta'
      if flags & BTRFS_BLOCK_GROUP_SYSTEM:
          if len(ret) > 0:
              ret += '|'
          ret += 'system'
      if flags & BTRFS_BLOCK_GROUP_RAID0:
          ret += ' raid0'
      elif flags & BTRFS_BLOCK_GROUP_RAID1:
          ret += ' raid1'
      elif flags & BTRFS_BLOCK_GROUP_DUP:
          ret += ' dup'
      elif flags & BTRFS_BLOCK_GROUP_RAID10:
          ret += ' raid10'
      elif flags & BTRFS_BLOCK_GROUP_RAID5:
          ret += ' raid5'
      elif flags & BTRFS_BLOCK_GROUP_RAID6:
          ret += ' raid6'
      elif flags & BTRFS_BLOCK_GROUP_RAID1C3:
          ret += ' raid1c3'
      elif flags & BTRFS_BLOCK_GROUP_RAID1C4:
          ret += ' raid1c4'
      else:
          ret += ' single'

      return ret

  def dump_bg(bg):
      print()
      print(f'block group at {hex(bg.value_())}')
      print(f'\t start {bg.start.value_()} length {bg.length.value_()}')
      print(f'\t flags {bg.flags.value_()} - {bg_flags_string(bg)}')

  bg_root = fs_info.block_group_cache_tree.address_of_()
  for bg in rbtree_inorder_for_each_entry('struct btrfs_block_group', bg_root, 'cache_node'):
      dump_bg(bg)

  $ drgn dump_block_groups.py

  block group at 0xffff8f3d673b0400
         start 22020096 length 16777216
         flags 258 - system raid6

  block group at 0xffff8f3d53ddb400
         start 38797312 length 536870912
         flags 260 - meta raid6

  block group at 0xffff8f3d5f4d9c00
         start 575668224 length 2147483648
         flags 257 - data raid6

  block group at 0xffff8f3d08189000
         start 2723151872 length 67108864
         flags 258 - system raid6

  block group at 0xffff8f3db70ff000
         start 2790260736 length 1073741824
         flags 260 - meta raid6

  block group at 0xffff8f3d5f4dd800
         start 3864002560 length 67108864
         flags 258 - system raid6

  block group at 0xffff8f3d67037000
         start 3931111424 length 2147483648
         flags 257 - data raid6
  $

So there were only 2 reasons left for having a readahead extent with a
single zone: reada_find_zone(), called when creating a readahead extent,
returned NULL either because we failed to find the corresponding block
group or because a memory allocation failed. With some additional and
custom tracing I figured out that on every further ocurrence of the
problem the block group had just been deleted when we were looping to
create the zones for the readahead extent (at reada_find_extent()), so we
ended up with only one zone in the readahead extent, corresponding to a
device that ends up getting replaced.

So after figuring that out it became obvious why the hang happens:

1) Task A starts a scrub on any device of the filesystem, except for
   device /dev/sdd;

2) Task B starts a device replace with /dev/sdd as the source device;

3) Task A calls btrfs_reada_add() from scrub_stripe() and it is currently
   starting to scrub a stripe from block group X. This call to
   btrfs_reada_add() is the one for the extent tree. When btrfs_reada_add()
   calls reada_add_block(), it passes the logical address of the extent
   tree's root node as its 'logical' argument - a value of 38928384;

4) Task A then enters reada_find_extent(), called from reada_add_block().
   It finds there isn't any existing readahead extent for the logical
   address 38928384, so it proceeds to the path of creating a new one.

   It calls btrfs_map_block() to find out which stripes exist for the block
   group X. On the first iteration of the for loop that iterates over the
   stripes, it finds the stripe for device /dev/sdd, so it creates one
   zone for that device and adds it to the readahead extent. Before getting
   into the second iteration of the loop, the cleanup kthread deletes block
   group X because it was empty. So in the iterations for the remaining
   stripes it does not add more zones to the readahead extent, because the
   calls to reada_find_zone() returned NULL because they couldn't find
   block group X anymore.

   As a result the new readahead extent has a single zone, corresponding to
   the device /dev/sdd;

4) Before task A returns to btrfs_reada_add() and queues the readahead job
   for the readahead work queue, task B finishes the device replace and at
   btrfs_dev_replace_finishing() swaps the device /dev/sdd with the new
   device /dev/sdg;

5) Task A returns to reada_add_block(), which increments the counter
   "->elems" of the reada_control structure allocated at btrfs_reada_add().

   Then it returns back to btrfs_reada_add() and calls
   reada_start_machine(). This queues a job in the readahead work queue to
   run the function reada_start_machine_worker(), which calls
   __reada_start_machine().

   At __reada_start_machine() we take the device list mutex and for each
   device found in the current device list, we call
   reada_start_machine_dev() to start the readahead work. However at this
   point the device /dev/sdd was already freed and is not in the device
   list anymore.

   This means the corresponding readahead for the extent at 38928384 is
   never started, and therefore the "->elems" counter of the reada_control
   structure allocated at btrfs_reada_add() never goes down to 0, causing
   the call to btrfs_reada_wait(), done by the scrub task, to wait forever.

Note that the readahead request can be made either after the device replace
started or before it started, however in pratice it is very unlikely that a
device replace is able to start after a readahead request is made and is
able to complete before the readahead request completes - maybe only on a
very small and nearly empty filesystem.

This hang however is not the only problem we can have with readahead and
device removals. When the readahead extent has other zones other than the
one corresponding to the device that is being removed (either by a device
replace or a device remove operation), we risk having a use-after-free on
the device when dropping the last reference of the readahead extent.

For example if we create a readahead extent with two zones, one for the
device /dev/sdd and one for the device /dev/sde:

1) Before the readahead worker starts, the device /dev/sdd is removed,
   and the corresponding btrfs_device structure is freed. However the
   readahead extent still has the zone pointing to the device structure;

2) When the readahead worker starts, it only finds device /dev/sde in the
   current device list of the filesystem;

3) It starts the readahead work, at reada_start_machine_dev(), using the
   device /dev/sde;

4) Then when it finishes reading the extent from device /dev/sde, it calls
   __readahead_hook() which ends up dropping the last reference on the
   readahead extent through the last call to reada_extent_put();

5) At reada_extent_put() it iterates over each zone of the readahead extent
   and attempts to delete an element from the device's 'reada_extents'
   radix tree, resulting in a use-after-free, as the device pointer of the
   zone for /dev/sdd is now stale. We can also access the device after
   dropping the last reference of a zone, through reada_zone_release(),
   also called by reada_extent_put().

And a device remove suffers the same problem, however since it shrinks the
device size down to zero before removing the device, it is very unlikely to
still have readahead requests not completed by the time we free the device,
the only possibility is if the device has a very little space allocated.

While the hang problem is exclusive to scrub, since it is currently the
only user of btrfs_reada_add() and btrfs_reada_wait(), the use-after-free
problem affects any path that triggers readhead, which includes
btree_readahead_hook() and __readahead_hook() (a readahead worker can
trigger readahed for the children of a node) for example - any path that
ends up calling reada_add_block() can trigger the use-after-free after a
device is removed.

So fix this by waiting for any readahead requests for a device to complete
before removing a device, ensuring that while waiting for existing ones no
new ones can be made.

This problem has been around for a very long time - the readahead code was
added in 2011, device remove exists since 2008 and device replace was
introduced in 2013, hard to pick a specific commit for a git Fixes tag.

CC: [email protected] # 4.4+
Reviewed-by: Josef Bacik <[email protected]>
Signed-off-by: Filipe Manana <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
friendlyarm referenced this issue in friendlyarm/kernel-rockchip Mar 3, 2021
commit 3a21777 upstream.

We had kernel panic, it is caused by unload module and last
close confirmation.

call trace:
[1196029.743127]  free_sess+0x15/0x50 [rtrs_client]
[1196029.743128]  rtrs_clt_close+0x4c/0x70 [rtrs_client]
[1196029.743129]  ? rnbd_clt_unmap_device+0x1b0/0x1b0 [rnbd_client]
[1196029.743130]  close_rtrs+0x25/0x50 [rnbd_client]
[1196029.743131]  rnbd_client_exit+0x93/0xb99 [rnbd_client]
[1196029.743132]  __x64_sys_delete_module+0x190/0x260

And in the crashdump confirmation kworker is also running.
PID: 6943   TASK: ffff9e2ac8098000  CPU: 4   COMMAND: "kworker/4:2"
 #0 [ffffb206cf337c30] __schedule at ffffffff9f93f891
 #1 [ffffb206cf337cc8] schedule at ffffffff9f93fe98
 #2 [ffffb206cf337cd0] schedule_timeout at ffffffff9f943938
 #3 [ffffb206cf337d50] wait_for_completion at ffffffff9f9410a7
 #4 [ffffb206cf337da0] __flush_work at ffffffff9f08ce0e
 #5 [ffffb206cf337e20] rtrs_clt_close_conns at ffffffffc0d5f668 [rtrs_client]
 #6 [ffffb206cf337e48] rtrs_clt_close at ffffffffc0d5f801 [rtrs_client]
 #7 [ffffb206cf337e68] close_rtrs at ffffffffc0d26255 [rnbd_client]
 #8 [ffffb206cf337e78] free_sess at ffffffffc0d262ad [rnbd_client]
 rockchip-linux#9 [ffffb206cf337e88] rnbd_clt_put_dev at ffffffffc0d266a7 [rnbd_client]

The problem is both code path try to close same session, which lead to
panic.

To fix it, just skip the sess if the refcount already drop to 0.

Fixes: f7a7a5c ("block/rnbd: client: main functionality")
Signed-off-by: Jack Wang <[email protected]>
Reviewed-by: Gioh Kim <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
friendlyarm referenced this issue in friendlyarm/kernel-rockchip Apr 2, 2021
[ Upstream commit c5c97ca ]

The ubsan reported the following error.  It was because sample's raw
data missed u32 padding at the end.  So it broke the alignment of the
array after it.

The raw data contains an u32 size prefix so the data size should have
an u32 padding after 8-byte aligned data.

27: Sample parsing  :util/synthetic-events.c:1539:4:
  runtime error: store to misaligned address 0x62100006b9bc for type
  '__u64' (aka 'unsigned long long'), which requires 8 byte alignment
0x62100006b9bc: note: pointer points here
  00 00 00 00 ff ff ff ff  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff
              ^
    #0 0x561532a9fc96 in perf_event__synthesize_sample util/synthetic-events.c:1539:13
    #1 0x5615327f4a4f in do_test tests/sample-parsing.c:284:8
    #2 0x5615327f3f50 in test__sample_parsing tests/sample-parsing.c:381:9
    #3 0x56153279d3a1 in run_test tests/builtin-test.c:424:9
    #4 0x56153279c836 in test_and_print tests/builtin-test.c:454:9
    #5 0x56153279b7eb in __cmd_test tests/builtin-test.c:675:4
    #6 0x56153279abf0 in cmd_test tests/builtin-test.c:821:9
    #7 0x56153264e796 in run_builtin perf.c:312:11
    #8 0x56153264cf03 in handle_internal_command perf.c:364:8
    rockchip-linux#9 0x56153264e47d in run_argv perf.c:408:2
    rockchip-linux#10 0x56153264c9a9 in main perf.c:538:3
    rockchip-linux#11 0x7f137ab6fbbc in __libc_start_main (/lib64/libc.so.6+0x38bbc)
    rockchip-linux#12 0x561532596828 in _start ...

SUMMARY: UndefinedBehaviorSanitizer: misaligned-pointer-use
 util/synthetic-events.c:1539:4 in

Fixes: 045f8cd ("perf tests: Add a sample parsing test")
Signed-off-by: Namhyung Kim <[email protected]>
Acked-by: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Ian Rogers <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
friendlyarm referenced this issue in friendlyarm/kernel-rockchip Apr 2, 2021
[ Upstream commit e8bd76e ]

kernel panic trace looks like:

 #5 [ffffb9e08698fc80] do_page_fault at ffffffffb666e0d7
 #6 [ffffb9e08698fcb0] page_fault at ffffffffb70010fe
    [exception RIP: amp_read_loc_assoc_final_data+63]
    RIP: ffffffffc06ab54f  RSP: ffffb9e08698fd68  RFLAGS: 00010246
    RAX: 0000000000000000  RBX: ffff8c8845a5a000  RCX: 0000000000000004
    RDX: 0000000000000000  RSI: ffff8c8b9153d000  RDI: ffff8c8845a5a000
    RBP: ffffb9e08698fe40   R8: 00000000000330e0   R9: ffffffffc0675c94
    R10: ffffb9e08698fe58  R11: 0000000000000001  R12: ffff8c8b9cbf6200
    R13: 0000000000000000  R14: 0000000000000000  R15: ffff8c8b2026da0b
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 #7 [ffffb9e08698fda8] hci_event_packet at ffffffffc0676904 [bluetooth]
 #8 [ffffb9e08698fe50] hci_rx_work at ffffffffc06629ac [bluetooth]
 rockchip-linux#9 [ffffb9e08698fe98] process_one_work at ffffffffb66f95e7

hcon->amp_mgr seems NULL triggered kernel panic in following line inside
function amp_read_loc_assoc_final_data

        set_bit(READ_LOC_AMP_ASSOC_FINAL, &mgr->state);

Fixed by checking NULL for mgr.

Signed-off-by: Gopal Tiwari <[email protected]>
Signed-off-by: Marcel Holtmann <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
friendlyarm referenced this issue in friendlyarm/kernel-rockchip Apr 2, 2021
commit 4d14c5c upstream

Calling btrfs_qgroup_reserve_meta_prealloc from
btrfs_delayed_inode_reserve_metadata can result in flushing delalloc
while holding a transaction and delayed node locks. This is deadlock
prone. In the past multiple commits:

 * ae5e070 ("btrfs: qgroup: don't try to wait flushing if we're
already holding a transaction")

 * 6f23277 ("btrfs: qgroup: don't commit transaction when we already
 hold the handle")

Tried to solve various aspects of this but this was always a
whack-a-mole game. Unfortunately those 2 fixes don't solve a deadlock
scenario involving btrfs_delayed_node::mutex. Namely, one thread
can call btrfs_dirty_inode as a result of reading a file and modifying
its atime:

  PID: 6963   TASK: ffff8c7f3f94c000  CPU: 2   COMMAND: "test"
  #0  __schedule at ffffffffa529e07d
  #1  schedule at ffffffffa529e4ff
  #2  schedule_timeout at ffffffffa52a1bdd
  #3  wait_for_completion at ffffffffa529eeea             <-- sleeps with delayed node mutex held
  #4  start_delalloc_inodes at ffffffffc0380db5
  #5  btrfs_start_delalloc_snapshot at ffffffffc0393836
  #6  try_flush_qgroup at ffffffffc03f04b2
  #7  __btrfs_qgroup_reserve_meta at ffffffffc03f5bb6     <-- tries to reserve space and starts delalloc inodes.
  #8  btrfs_delayed_update_inode at ffffffffc03e31aa      <-- acquires delayed node mutex
  rockchip-linux#9  btrfs_update_inode at ffffffffc0385ba8
 rockchip-linux#10  btrfs_dirty_inode at ffffffffc038627b               <-- TRANSACTIION OPENED
 rockchip-linux#11  touch_atime at ffffffffa4cf0000
 rockchip-linux#12  generic_file_read_iter at ffffffffa4c1f123
 rockchip-linux#13  new_sync_read at ffffffffa4ccdc8a
 rockchip-linux#14  vfs_read at ffffffffa4cd0849
 rockchip-linux#15  ksys_read at ffffffffa4cd0bd1
 rockchip-linux#16  do_syscall_64 at ffffffffa4a052eb
 rockchip-linux#17  entry_SYSCALL_64_after_hwframe at ffffffffa540008c

This will cause an asynchronous work to flush the delalloc inodes to
happen which can try to acquire the same delayed_node mutex:

  PID: 455    TASK: ffff8c8085fa4000  CPU: 5   COMMAND: "kworker/u16:30"
  #0  __schedule at ffffffffa529e07d
  #1  schedule at ffffffffa529e4ff
  #2  schedule_preempt_disabled at ffffffffa529e80a
  #3  __mutex_lock at ffffffffa529fdcb                    <-- goes to sleep, never wakes up.
  #4  btrfs_delayed_update_inode at ffffffffc03e3143      <-- tries to acquire the mutex
  #5  btrfs_update_inode at ffffffffc0385ba8              <-- this is the same inode that pid 6963 is holding
  #6  cow_file_range_inline.constprop.78 at ffffffffc0386be7
  #7  cow_file_range at ffffffffc03879c1
  #8  btrfs_run_delalloc_range at ffffffffc038894c
  rockchip-linux#9  writepage_delalloc at ffffffffc03a3c8f
 rockchip-linux#10  __extent_writepage at ffffffffc03a4c01
 rockchip-linux#11  extent_write_cache_pages at ffffffffc03a500b
 rockchip-linux#12  extent_writepages at ffffffffc03a6de2
 rockchip-linux#13  do_writepages at ffffffffa4c277eb
 rockchip-linux#14  __filemap_fdatawrite_range at ffffffffa4c1e5bb
 rockchip-linux#15  btrfs_run_delalloc_work at ffffffffc0380987         <-- starts running delayed nodes
 rockchip-linux#16  normal_work_helper at ffffffffc03b706c
 rockchip-linux#17  process_one_work at ffffffffa4aba4e4
 rockchip-linux#18  worker_thread at ffffffffa4aba6fd
 rockchip-linux#19  kthread at ffffffffa4ac0a3d
 rockchip-linux#20  ret_from_fork at ffffffffa54001ff

To fully address those cases the complete fix is to never issue any
flushing while holding the transaction or the delayed node lock. This
patch achieves it by calling qgroup_reserve_meta directly which will
either succeed without flushing or will fail and return -EDQUOT. In the
latter case that return value is going to be propagated to
btrfs_dirty_inode which will fallback to start a new transaction. That's
fine as the majority of time we expect the inode will have
BTRFS_DELAYED_NODE_INODE_DIRTY flag set which will result in directly
copying the in-memory state.

Fixes: c53e965 ("btrfs: qgroup: try to flush qgroup space when we get -EDQUOT")
CC: [email protected] # 5.10+
Reviewed-by: Qu Wenruo <[email protected]>
Signed-off-by: Nikolay Borisov <[email protected]>
Signed-off-by: David Sterba <[email protected]>
[sudip: adjust context]
Signed-off-by: Sudip Mukherjee <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
friendlyarm referenced this issue in friendlyarm/kernel-rockchip Jun 15, 2021
[ Upstream commit bbd6f0a ]

In bnxt_rx_pkt(), the RX buffers are expected to complete in order.
If the RX consumer index indicates an out of order buffer completion,
it means we are hitting a hardware bug and the driver will abort all
remaining RX packets and reset the RX ring.  The RX consumer index
that we pass to bnxt_discard_rx() is not correct.  We should be
passing the current index (tmp_raw_cons) instead of the old index
(raw_cons).  This bug can cause us to be at the wrong index when
trying to abort the next RX packet.  It can crash like this:

 #0 [ffff9bbcdf5c39a8] machine_kexec at ffffffff9b05e007
 #1 [ffff9bbcdf5c3a00] __crash_kexec at ffffffff9b111232
 #2 [ffff9bbcdf5c3ad0] panic at ffffffff9b07d61e
 #3 [ffff9bbcdf5c3b50] oops_end at ffffffff9b030978
 #4 [ffff9bbcdf5c3b78] no_context at ffffffff9b06aaf0
 #5 [ffff9bbcdf5c3bd8] __bad_area_nosemaphore at ffffffff9b06ae2e
 #6 [ffff9bbcdf5c3c28] bad_area_nosemaphore at ffffffff9b06af24
 #7 [ffff9bbcdf5c3c38] __do_page_fault at ffffffff9b06b67e
 #8 [ffff9bbcdf5c3cb0] do_page_fault at ffffffff9b06bb12
 rockchip-linux#9 [ffff9bbcdf5c3ce0] page_fault at ffffffff9bc015c5
    [exception RIP: bnxt_rx_pkt+237]
    RIP: ffffffffc0259cdd  RSP: ffff9bbcdf5c3d98  RFLAGS: 00010213
    RAX: 000000005dd8097f  RBX: ffff9ba4cb11b7e0  RCX: ffffa923cf6e9000
    RDX: 0000000000000fff  RSI: 0000000000000627  RDI: 0000000000001000
    RBP: ffff9bbcdf5c3e60   R8: 0000000000420003   R9: 000000000000020d
    R10: ffffa923cf6ec138  R11: ffff9bbcdf5c3e83  R12: ffff9ba4d6f928c0
    R13: ffff9ba4cac28080  R14: ffff9ba4cb11b7f0  R15: ffff9ba4d5a30000
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018

Fixes: a1b0e4e ("bnxt_en: Improve RX consumer index validity check.")
Reviewed-by: Pavan Chebbi <[email protected]>
Reviewed-by: Andy Gospodarek <[email protected]>
Signed-off-by: Michael Chan <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
friendlyarm referenced this issue in friendlyarm/kernel-rockchip Aug 23, 2022
commit 2b12993 upstream.

tl;dr: The Enhanced IBRS mitigation for Spectre v2 does not work as
documented for RET instructions after VM exits. Mitigate it with a new
one-entry RSB stuffing mechanism and a new LFENCE.

== Background ==

Indirect Branch Restricted Speculation (IBRS) was designed to help
mitigate Branch Target Injection and Speculative Store Bypass, i.e.
Spectre, attacks. IBRS prevents software run in less privileged modes
from affecting branch prediction in more privileged modes. IBRS requires
the MSR to be written on every privilege level change.

To overcome some of the performance issues of IBRS, Enhanced IBRS was
introduced.  eIBRS is an "always on" IBRS, in other words, just turn
it on once instead of writing the MSR on every privilege level change.
When eIBRS is enabled, more privileged modes should be protected from
less privileged modes, including protecting VMMs from guests.

== Problem ==

Here's a simplification of how guests are run on Linux' KVM:

void run_kvm_guest(void)
{
	// Prepare to run guest
	VMRESUME();
	// Clean up after guest runs
}

The execution flow for that would look something like this to the
processor:

1. Host-side: call run_kvm_guest()
2. Host-side: VMRESUME
3. Guest runs, does "CALL guest_function"
4. VM exit, host runs again
5. Host might make some "cleanup" function calls
6. Host-side: RET from run_kvm_guest()

Now, when back on the host, there are a couple of possible scenarios of
post-guest activity the host needs to do before executing host code:

* on pre-eIBRS hardware (legacy IBRS, or nothing at all), the RSB is not
touched and Linux has to do a 32-entry stuffing.

* on eIBRS hardware, VM exit with IBRS enabled, or restoring the host
IBRS=1 shortly after VM exit, has a documented side effect of flushing
the RSB except in this PBRSB situation where the software needs to stuff
the last RSB entry "by hand".

IOW, with eIBRS supported, host RET instructions should no longer be
influenced by guest behavior after the host retires a single CALL
instruction.

However, if the RET instructions are "unbalanced" with CALLs after a VM
exit as is the RET in #6, it might speculatively use the address for the
instruction after the CALL in #3 as an RSB prediction. This is a problem
since the (untrusted) guest controls this address.

Balanced CALL/RET instruction pairs such as in step #5 are not affected.

== Solution ==

The PBRSB issue affects a wide variety of Intel processors which
support eIBRS. But not all of them need mitigation. Today,
X86_FEATURE_RSB_VMEXIT triggers an RSB filling sequence that mitigates
PBRSB. Systems setting RSB_VMEXIT need no further mitigation - i.e.,
eIBRS systems which enable legacy IBRS explicitly.

However, such systems (X86_FEATURE_IBRS_ENHANCED) do not set RSB_VMEXIT
and most of them need a new mitigation.

Therefore, introduce a new feature flag X86_FEATURE_RSB_VMEXIT_LITE
which triggers a lighter-weight PBRSB mitigation versus RSB_VMEXIT.

The lighter-weight mitigation performs a CALL instruction which is
immediately followed by a speculative execution barrier (INT3). This
steers speculative execution to the barrier -- just like a retpoline
-- which ensures that speculation can never reach an unbalanced RET.
Then, ensure this CALL is retired before continuing execution with an
LFENCE.

In other words, the window of exposure is opened at VM exit where RET
behavior is troublesome. While the window is open, force RSB predictions
sampling for RET targets to a dead end at the INT3. Close the window
with the LFENCE.

There is a subset of eIBRS systems which are not vulnerable to PBRSB.
Add these systems to the cpu_vuln_whitelist[] as NO_EIBRS_PBRSB.
Future systems that aren't vulnerable will set ARCH_CAP_PBRSB_NO.

  [ bp: Massage, incorporate review comments from Andy Cooper. ]

Signed-off-by: Daniel Sneddon <[email protected]>
Co-developed-by: Pawan Gupta <[email protected]>
Signed-off-by: Pawan Gupta <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
friendlyarm referenced this issue in friendlyarm/kernel-rockchip Aug 23, 2022
commit 59c026c upstream.

When use 'echo c > /proc/sysrq-trigger' to trigger kdump, riscv_crash_save_regs()
will be called to save regs for vmcore, we found "epc" value 00ffffffa5537400
is not a valid kernel virtual address, but is a user virtual address. Other
regs(eg, ra, sp, gp...) are correct kernel virtual address.
Actually 0x00ffffffb0dd9400 is the user mode PC of 'PID: 113 Comm: sh', which
is saved in the task's stack.

[   21.201701] CPU: 0 PID: 113 Comm: sh Kdump: loaded Not tainted 5.18.9 rockchip-linux#45
[   21.201979] Hardware name: riscv-virtio,qemu (DT)
[   21.202160] epc : 00ffffffa5537400 ra : ffffffff80088640 sp : ff20000010333b90
[   21.202435]  gp : ffffffff810dde38 tp : ff6000000226c200 t0 : ffffffff8032be7c
[   21.202707]  t1 : 0720072007200720 t2 : 30203a7375746174 s0 : ff20000010333cf0
[   21.202973]  s1 : 0000000000000000 a0 : ff20000010333b98 a1 : 0000000000000001
[   21.203243]  a2 : 0000000000000010 a3 : 0000000000000000 a4 : 28c8f0aeffea4e00
[   21.203519]  a5 : 28c8f0aeffea4e00 a6 : 0000000000000009 a7 : ffffffff8035c9b8
[   21.203794]  s2 : ffffffff810df0a8 s3 : ffffffff810df718 s4 : ff20000010333b98
[   21.204062]  s5 : 0000000000000000 s6 : 0000000000000007 s7 : ffffffff80c4a468
[   21.204331]  s8 : 00ffffffef451410 s9 : 0000000000000007 s10: 00aaaaaac0510700
[   21.204606]  s11: 0000000000000001 t3 : ff60000001218f00 t4 : ff60000001218f00
[   21.204876]  t5 : ff60000001218000 t6 : ff200000103338b8
[   21.205079] status: 0000000200000020 badaddr: 0000000000000000 cause: 0000000000000008

With the incorrect PC, the backtrace showed by crash tool as below, the first
stack frame is abnormal,

crash> bt
PID: 113      TASK: ff60000002269600  CPU: 0    COMMAND: "sh"
 #0 [ff2000001039bb90] __efistub_.Ldebug_info0 at 00ffffffa5537400 <-- Abnormal
 #1 [ff2000001039bcf0] panic at ffffffff806578ba
 #2 [ff2000001039bd50] sysrq_reset_seq_param_set at ffffffff8038c030
 #3 [ff2000001039bda0] __handle_sysrq at ffffffff8038c5f8
 #4 [ff2000001039be00] write_sysrq_trigger at ffffffff8038cad8
 #5 [ff2000001039be20] proc_reg_write at ffffffff801b7edc
 #6 [ff2000001039be40] vfs_write at ffffffff80152ba6
 #7 [ff2000001039be80] ksys_write at ffffffff80152ece
 #8 [ff2000001039bed0] sys_write at ffffffff80152f46

With the patch, we can get current kernel mode PC, the output as below,

[   17.607658] CPU: 0 PID: 113 Comm: sh Kdump: loaded Not tainted 5.18.9 rockchip-linux#42
[   17.607937] Hardware name: riscv-virtio,qemu (DT)
[   17.608150] epc : ffffffff800078f8 ra : ffffffff8008862c sp : ff20000010333b90
[   17.608441]  gp : ffffffff810dde38 tp : ff6000000226c200 t0 : ffffffff8032be68
[   17.608741]  t1 : 0720072007200720 t2 : 666666666666663c s0 : ff20000010333cf0
[   17.609025]  s1 : 0000000000000000 a0 : ff20000010333b98 a1 : 0000000000000001
[   17.609320]  a2 : 0000000000000010 a3 : 0000000000000000 a4 : 0000000000000000
[   17.609601]  a5 : ff60000001c78000 a6 : 000000000000003c a7 : ffffffff8035c9a4
[   17.609894]  s2 : ffffffff810df0a8 s3 : ffffffff810df718 s4 : ff20000010333b98
[   17.610186]  s5 : 0000000000000000 s6 : 0000000000000007 s7 : ffffffff80c4a468
[   17.610469]  s8 : 00ffffffca281410 s9 : 0000000000000007 s10: 00aaaaaab5bb6700
[   17.610755]  s11: 0000000000000001 t3 : ff60000001218f00 t4 : ff60000001218f00
[   17.611041]  t5 : ff60000001218000 t6 : ff20000010333988
[   17.611255] status: 0000000200000020 badaddr: 0000000000000000 cause: 0000000000000008

With the correct PC, the backtrace showed by crash tool as below,

crash> bt
PID: 113      TASK: ff6000000226c200  CPU: 0    COMMAND: "sh"
 #0 [ff20000010333b90] riscv_crash_save_regs at ffffffff800078f8 <--- Normal
 #1 [ff20000010333cf0] panic at ffffffff806578c6
 #2 [ff20000010333d50] sysrq_reset_seq_param_set at ffffffff8038c03c
 #3 [ff20000010333da0] __handle_sysrq at ffffffff8038c604
 #4 [ff20000010333e00] write_sysrq_trigger at ffffffff8038cae4
 #5 [ff20000010333e20] proc_reg_write at ffffffff801b7ee8
 #6 [ff20000010333e40] vfs_write at ffffffff80152bb2
 #7 [ff20000010333e80] ksys_write at ffffffff80152eda
 #8 [ff20000010333ed0] sys_write at ffffffff80152f52

Fixes: e53d281 ("RISC-V: Add kdump support")
Co-developed-by: Guo Ren <[email protected]>
Signed-off-by: Xianting Tian <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Cc: [email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
friendlyarm referenced this issue in friendlyarm/kernel-rockchip Oct 31, 2022
This patch add support for DMA-based digital loopback.

BACKGROUND
Audio Products with AEC require loopback for echo cancellation.
the hardware LP is not always available on some products, maybe
the HW limitation(such as internal acodec) or HW Cost-down.

This patch add support software DLP for such products.

Enable:

  CONFIG_SND_SOC_ROCKCHIP_DLP

  &i2s {
      rockchip,digital-loopback;
  };

Mode List:

  amixer contents
  numid=2,iface=MIXER,name='Software Digital Loopback Mode'
    ; type=ENUMERATED,access=rw------,values=1,items=7
    ; Item #0 'Disabled'
    ; Item #1 '2CH: 1 Loopback + 1 Mic'
    ; Item #2 '2CH: 1 Mic + 1 Loopback'
    ; Item #3 '2CH: 1 Mic + 1 Loopback-mixed'
    ; Item #4 '2CH: 2 Loopbacks'
    ; Item #5 '4CH: 2 Mics + 2 Loopbacks'
    ; Item #6 '4CH: 2 Mics + 1 Loopback-mixed'
    : values=0

Testenv:

wired SDO0 --> SDI0 directly to get external digital loopback
as reference.

Testcase: dlp.sh

  /#!/bin/sh

  item=0
  id=`amixer contents | grep "Software Digital Loopback" | \
      awk -F ',' '{print $1}'`

  items=`amixer contents | grep -A 1 "Software Digital Loopback" | \
         grep items | awk -F 'items=' '{print $2}'`

  echo "Software Digital Loopback: $id, items: $items"

  mode_chs() {
          case $1 in
          [0-4])
                  echo "2"
                  ;;
          [5-6])
                  echo "4"
                  ;;
          *)
                  echo "2"
                  ;;
          esac
  }

  while true
  do
          ch=`mode_chs $item`
          amixer -c 0 cset $id $item
          arecord -D hw:0,0 --period-size=1024 --buffer-size=4096 -r 48000 -c $ch -f s16_le \
                  -d 15 sine/dlp_$item.wav &
          sleep 2
          for i in $(seq 1 10)
          do
                  aplay -D hw:0,0 --period-size=1024 --buffer-size=8192 $((ch))ch.wav -d 1
          done
          pid=$(ps | egrep "aplay|arecord" | grep -v grep | awk '{print $1}' | sort -r)
          for p in $pid
          do
                  wait $p 2>/dev/null
          done
          item=$((item+1))
          if [ $item -ge $items ]; then
                  sleep 1
                  break
          fi
  done
  echo "Done"

Result:

do shell test and verify dlp_x.wav:

* Alignment: ~1 samples shift (loopback <-> mics).
* Integrity: no giltch, no data lost.
* AEC: align loopback and mics sample and do simple AEC, get clean
  waveform.

Logs:
...
numid=2,iface=MIXER,name='Software Digital Loopback Mode'
  ; type=ENUMERATED,access=rw------,values=1,items=7
  ; Item #0 'Disabled'
  ; Item #1 '2CH: 1 Loopback + 1 Mic'
  ; Item #2 '2CH: 1 Mic + 1 Loopback'
  ; Item #3 '2CH: 1 Mic + 1 Loopback-mixed'
  ; Item #4 '2CH: 2 Loopbacks'
  ; Item #5 '4CH: 2 Mics + 2 Loopbacks'
  ; Item #6 '4CH: 2 Mics + 1 Loopback-mixed'
  : values=2
Recording WAVE 'sine/dlp_2.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Playing WAVE '2ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Playing WAVE '2ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Playing WAVE '2ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Playing WAVE '2ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Playing WAVE '2ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Playing WAVE '2ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Playing WAVE '2ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Playing WAVE '2ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Playing WAVE '2ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Playing WAVE '2ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
...
numid=2,iface=MIXER,name='Software Digital Loopback Mode'
  ; type=ENUMERATED,access=rw------,values=1,items=7
  ; Item #0 'Disabled'
  ; Item #1 '2CH: 1 Loopback + 1 Mic'
  ; Item #2 '2CH: 1 Mic + 1 Loopback'
  ; Item #3 '2CH: 1 Mic + 1 Loopback-mixed'
  ; Item #4 '2CH: 2 Loopbacks'
  ; Item #5 '4CH: 2 Mics + 2 Loopbacks'
  ; Item #6 '4CH: 2 Mics + 1 Loopback-mixed'
  : values=6
Recording WAVE 'sine/dlp_6.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 4
Playing WAVE '4ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 4
Playing WAVE '4ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 4
Playing WAVE '4ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 4
Playing WAVE '4ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 4
Playing WAVE '4ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 4
Playing WAVE '4ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 4
Playing WAVE '4ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 4
Playing WAVE '4ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 4
Playing WAVE '4ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 4
Playing WAVE '4ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 4
Done

Signed-off-by: Sugar Zhang <[email protected]>
Change-Id: I5772f0694f7a14a0f0bd1f0777b6c4cdbd781a64
Caesar-github pushed a commit that referenced this issue Nov 3, 2022
…lock_t for PREEMPT_RT

<3>[  141.648698][    C0] BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:970
<3>[  141.648723][    C0] in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 0, name: swapper/0
<4>[  141.648739][    C0] INFO: lockdep is turned off.
<4>[  141.648745][    C0] irq event stamp: 22142
<4>[  141.648751][    C0] hardirqs last  enabled at (22141): [<ffffffc010139a98>] tick_nohz_idle_exit+0x90/0x134
<4>[  141.648785][    C0] hardirqs last disabled at (22142): [<ffffffc01139fdd8>] __schedule+0x80/0x6d4
<4>[  141.648812][    C0] softirqs last  enabled at (2818): [<ffffffc010056c20>] __local_bh_enable_ip+0x1f4/0x258
<4>[  141.648840][    C0] softirqs last disabled at (2812): [<ffffffc01015f654>] local_bh_disable+0x4/0x30
<3>[  141.648867][    C0] Preemption disabled at:
<3>[  141.648872][    C0] [<ffffffc0113a0570>] schedule_preempt_disabled+0x20/0x2c
<4>[  141.648900][    C0] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G        W         5.10.66-rt53 #6
<4>[  141.648918][    C0] Hardware name: Rockchip RK3588 EVB1 LP4 V10 Board (DT)
<4>[  141.648927][    C0] Call trace:
<4>[  141.648932][    C0]  dump_backtrace+0x0/0x1c4
<4>[  141.648956][    C0]  show_stack+0x18/0x24
<4>[  141.648977][    C0]  dump_stack_lvl+0xec/0x148
<4>[  141.648993][    C0]  dump_stack+0x18/0x64
<4>[  141.649008][    C0]  ___might_sleep+0x1b4/0x1c4
<4>[  141.649030][    C0]  rt_spin_lock+0x70/0xd8
<4>[  141.649046][    C0]  log_abnormal_wakeup_reason+0x64/0xd8
<4>[  141.649066][    C0]  handle_fasteoi_irq+0x224/0x228
<4>[  141.649084][    C0]  __handle_domain_irq+0xb0/0x11c
<4>[  141.649105][    C0]  gic_handle_irq+0x74/0x14c
<4>[  141.649123][    C0]  el1_irq+0xd0/0x1c0
<4>[  141.649138][    C0]  cpuidle_enter_state+0x184/0x2d0
<4>[  141.649156][    C0]  cpuidle_enter+0x38/0x50
<4>[  141.649170][    C0]  cpuidle_idle_call+0x188/0x278
<4>[  141.649189][    C0]  do_idle+0xb8/0x10c
<4>[  141.649205][    C0]  cpu_startup_entry+0x24/0x28
<4>[  141.649222][    C0]  rest_init+0x1ec/0x1fc
<4>[  141.649240][    C0]  arch_call_rest_init+0x10/0x1c
<4>[  141.649260][    C0]  start_kernel+0x3f0/0x524

Signed-off-by: Liang Chen <[email protected]>
Change-Id: I383164b2a646250d34dc7c085e7a1d297889581e
friendlyarm referenced this issue in friendlyarm/kernel-rockchip Nov 12, 2022
commit c3ed222 upstream.

Send along the already-allocated fattr along with nfs4_fs_locations, and
drop the memcpy of fattr.  We end up growing two more allocations, but this
fixes up a crash as:

PID: 790    TASK: ffff88811b43c000  CPU: 0   COMMAND: "ls"
 #0 [ffffc90000857920] panic at ffffffff81b9bfde
 #1 [ffffc900008579c0] do_trap at ffffffff81023a9b
 #2 [ffffc90000857a10] do_error_trap at ffffffff81023b78
 #3 [ffffc90000857a58] exc_stack_segment at ffffffff81be1f45
 #4 [ffffc90000857a80] asm_exc_stack_segment at ffffffff81c009de
 #5 [ffffc90000857b08] nfs_lookup at ffffffffa0302322 [nfs]
 #6 [ffffc90000857b70] __lookup_slow at ffffffff813a4a5f
 #7 [ffffc90000857c60] walk_component at ffffffff813a86c4
 #8 [ffffc90000857cb8] path_lookupat at ffffffff813a9553
 rockchip-linux#9 [ffffc90000857cf0] filename_lookup at ffffffff813ab86b

Suggested-by: Trond Myklebust <[email protected]>
Fixes: 9558a00 ("NFS: Remove the label from the nfs4_lookup_res struct")
Signed-off-by: Benjamin Coddington <[email protected]>
Signed-off-by: Anna Schumaker <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
friendlyarm referenced this issue in friendlyarm/kernel-rockchip Nov 12, 2022
commit 4f40a5b upstream.

This was missed in c3ed222 ("NFSv4: Fix free of uninitialized
nfs4_label on referral lookup.") and causes a panic when mounting
with '-o trunkdiscovery':

PID: 1604   TASK: ffff93dac3520000  CPU: 3   COMMAND: "mount.nfs"
 #0 [ffffb79140f738f8] machine_kexec at ffffffffaec64bee
 #1 [ffffb79140f73950] __crash_kexec at ffffffffaeda67fd
 #2 [ffffb79140f73a18] crash_kexec at ffffffffaeda76ed
 #3 [ffffb79140f73a30] oops_end at ffffffffaec2658d
 #4 [ffffb79140f73a50] general_protection at ffffffffaf60111e
    [exception RIP: nfs_fattr_init+0x5]
    RIP: ffffffffc0c18265  RSP: ffffb79140f73b08  RFLAGS: 00010246
    RAX: 0000000000000000  RBX: ffff93dac304a800  RCX: 0000000000000000
    RDX: ffffb79140f73bb0  RSI: ffff93dadc8cbb40  RDI: d03ee11cfaf6bd50
    RBP: ffffb79140f73be8   R8: ffffffffc0691560   R9: 0000000000000006
    R10: ffff93db3ffd3df8  R11: 0000000000000000  R12: ffff93dac4040000
    R13: ffff93dac2848e00  R14: ffffb79140f73b60  R15: ffffb79140f73b30
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 #5 [ffffb79140f73b08] _nfs41_proc_get_locations at ffffffffc0c73d53 [nfsv4]
 #6 [ffffb79140f73bf0] nfs4_proc_get_locations at ffffffffc0c83e90 [nfsv4]
 #7 [ffffb79140f73c60] nfs4_discover_trunking at ffffffffc0c83fb7 [nfsv4]
 #8 [ffffb79140f73cd8] nfs_probe_fsinfo at ffffffffc0c0f95f [nfs]
 rockchip-linux#9 [ffffb79140f73da0] nfs_probe_server at ffffffffc0c1026a [nfs]
    RIP: 00007f6254fce26e  RSP: 00007ffc69496ac8  RFLAGS: 00000246
    RAX: ffffffffffffffda  RBX: 0000000000000000  RCX: 00007f6254fce26e
    RDX: 00005600220a82a0  RSI: 00005600220a64d0  RDI: 00005600220a6520
    RBP: 00007ffc69496c50   R8: 00005600220a8710   R9: 003035322e323231
    R10: 0000000000000000  R11: 0000000000000246  R12: 00007ffc69496c50
    R13: 00005600220a8440  R14: 0000000000000010  R15: 0000560020650ef9
    ORIG_RAX: 00000000000000a5  CS: 0033  SS: 002b

Fixes: c3ed222 ("NFSv4: Fix free of uninitialized nfs4_label on referral lookup.")
Signed-off-by: Scott Mayhew <[email protected]>
Signed-off-by: Anna Schumaker <[email protected]>
Signed-off-by: Trond Myklebust <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
pksg referenced this issue in tesors/linux-rockchip Mar 10, 2023
clk: Disable writable debugfs files
hejiawencc pushed a commit to LubanCat/kernel that referenced this issue Jan 10, 2024
This patch add support for DMA-based digital loopback.

BACKGROUND
Audio Products with AEC require loopback for echo cancellation.
the hardware LP is not always available on some products, maybe
the HW limitation(such as internal acodec) or HW Cost-down.

This patch add support software DLP for such products.

Enable:

  CONFIG_SND_SOC_ROCKCHIP_DLP

  &i2s {
      rockchip,digital-loopback;
  };

Mode List:

  amixer contents
  numid=2,iface=MIXER,name='Software Digital Loopback Mode'
    ; type=ENUMERATED,access=rw------,values=1,items=7
    ; Item #0 'Disabled'
    ; Item #1 '2CH: 1 Loopback + 1 Mic'
    ; Item #2 '2CH: 1 Mic + 1 Loopback'
    ; Item rockchip-linux#3 '2CH: 1 Mic + 1 Loopback-mixed'
    ; Item rockchip-linux#4 '2CH: 2 Loopbacks'
    ; Item rockchip-linux#5 '4CH: 2 Mics + 2 Loopbacks'
    ; Item rockchip-linux#6 '4CH: 2 Mics + 1 Loopback-mixed'
    : values=0

Testenv:

wired SDO0 --> SDI0 directly to get external digital loopback
as reference.

Testcase: dlp.sh

  /#!/bin/sh

  item=0
  id=`amixer contents | grep "Software Digital Loopback" | \
      awk -F ',' '{print $1}'`

  items=`amixer contents | grep -A 1 "Software Digital Loopback" | \
         grep items | awk -F 'items=' '{print $2}'`

  echo "Software Digital Loopback: $id, items: $items"

  mode_chs() {
          case $1 in
          [0-4])
                  echo "2"
                  ;;
          [5-6])
                  echo "4"
                  ;;
          *)
                  echo "2"
                  ;;
          esac
  }

  while true
  do
          ch=`mode_chs $item`
          amixer -c 0 cset $id $item
          arecord -D hw:0,0 --period-size=1024 --buffer-size=4096 -r 48000 -c $ch -f s16_le \
                  -d 15 sine/dlp_$item.wav &
          sleep 2
          for i in $(seq 1 10)
          do
                  aplay -D hw:0,0 --period-size=1024 --buffer-size=8192 $((ch))ch.wav -d 1
          done
          pid=$(ps | egrep "aplay|arecord" | grep -v grep | awk '{print $1}' | sort -r)
          for p in $pid
          do
                  wait $p 2>/dev/null
          done
          item=$((item+1))
          if [ $item -ge $items ]; then
                  sleep 1
                  break
          fi
  done
  echo "Done"

Result:

do shell test and verify dlp_x.wav:

* Alignment: ~1 samples shift (loopback <-> mics).
* Integrity: no giltch, no data lost.
* AEC: align loopback and mics sample and do simple AEC, get clean
  waveform.

Logs:
...
numid=2,iface=MIXER,name='Software Digital Loopback Mode'
  ; type=ENUMERATED,access=rw------,values=1,items=7
  ; Item #0 'Disabled'
  ; Item #1 '2CH: 1 Loopback + 1 Mic'
  ; Item #2 '2CH: 1 Mic + 1 Loopback'
  ; Item rockchip-linux#3 '2CH: 1 Mic + 1 Loopback-mixed'
  ; Item rockchip-linux#4 '2CH: 2 Loopbacks'
  ; Item rockchip-linux#5 '4CH: 2 Mics + 2 Loopbacks'
  ; Item rockchip-linux#6 '4CH: 2 Mics + 1 Loopback-mixed'
  : values=2
Recording WAVE 'sine/dlp_2.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Playing WAVE '2ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Playing WAVE '2ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Playing WAVE '2ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Playing WAVE '2ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Playing WAVE '2ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Playing WAVE '2ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Playing WAVE '2ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Playing WAVE '2ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Playing WAVE '2ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Playing WAVE '2ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
...
numid=2,iface=MIXER,name='Software Digital Loopback Mode'
  ; type=ENUMERATED,access=rw------,values=1,items=7
  ; Item #0 'Disabled'
  ; Item #1 '2CH: 1 Loopback + 1 Mic'
  ; Item #2 '2CH: 1 Mic + 1 Loopback'
  ; Item rockchip-linux#3 '2CH: 1 Mic + 1 Loopback-mixed'
  ; Item rockchip-linux#4 '2CH: 2 Loopbacks'
  ; Item rockchip-linux#5 '4CH: 2 Mics + 2 Loopbacks'
  ; Item rockchip-linux#6 '4CH: 2 Mics + 1 Loopback-mixed'
  : values=6
Recording WAVE 'sine/dlp_6.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 4
Playing WAVE '4ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 4
Playing WAVE '4ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 4
Playing WAVE '4ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 4
Playing WAVE '4ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 4
Playing WAVE '4ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 4
Playing WAVE '4ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 4
Playing WAVE '4ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 4
Playing WAVE '4ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 4
Playing WAVE '4ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 4
Playing WAVE '4ch.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 4
Done

Signed-off-by: Sugar Zhang <[email protected]>
Change-Id: I5772f0694f7a14a0f0bd1f0777b6c4cdbd781a64
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