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qemu-user emulator images core dump when emulating linux/amd64, linux/s390x with p_rcu_reader->depth != 0 #33

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maxheld83 opened this issue Jun 6, 2022 · 0 comments
Open

qemu-user emulator images core dump when emulating linux/amd64, linux/s390x with p_rcu_reader->depth != 0 #33

maxheld83 opened this issue Jun 6, 2022 · 0 comments

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@maxheld83
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this is crossposted from tonistiigi/binfmt, see there for details/reproducible example.
(Not repeating that here, because ... DRY).

It seems that asahi may be relevant, b/c @tonistiigi could not reproduce the issue on Apple M1 (under macOS).
@maxheld83 maxheld83 mentioned this issue Jun 6, 2022
Open
marcan pushed a commit that referenced this issue Dec 12, 2022
@swkim101 @Vudentz
Bluetooth: L2CAP: Fix u8 overflow
bcd7026 
By keep sending L2CAP_CONF_REQ packets, chan->num_conf_rsp increases
multiple times and eventually it will wrap around the maximum number
(i.e., 255).
This patch prevents this by adding a boundary check with
L2CAP_MAX_CONF_RSP

Btmon log:
Bluetooth monitor ver 5.64
= Note: Linux version 6.1.0-rc2 (x86_64)                               0.264594
= Note: Bluetooth subsystem version 2.22                               0.264636
@ MGMT Open: btmon (privileged) version 1.22                  {0x0001} 0.272191
= New Index: 00:00:00:00:00:00 (Primary,Virtual,hci0)          [hci0] 13.877604
@ RAW Open: 9496 (privileged) version 2.22                   {0x0002} 13.890741
= Open Index: 00:00:00:00:00:00                                [hci0] 13.900426
(...)
> ACL Data RX: Handle 200 flags 0x00 dlen 1033             #32 [hci0] 14.273106
        invalid packet size (12 != 1033)
        08 00 01 00 02 01 04 00 01 10 ff ff              ............
> ACL Data RX: Handle 200 flags 0x00 dlen 1547             #33 [hci0] 14.273561
        invalid packet size (14 != 1547)
        0a 00 01 00 04 01 06 00 40 00 00 00 00 00        ........@.....
> ACL Data RX: Handle 200 flags 0x00 dlen 2061             #34 [hci0] 14.274390
        invalid packet size (16 != 2061)
        0c 00 01 00 04 01 08 00 40 00 00 00 00 00 00 04  ........@.......
> ACL Data RX: Handle 200 flags 0x00 dlen 2061             #35 [hci0] 14.274932
        invalid packet size (16 != 2061)
        0c 00 01 00 04 01 08 00 40 00 00 00 07 00 03 00  ........@.......
= bluetoothd: Bluetooth daemon 5.43                                   14.401828
> ACL Data RX: Handle 200 flags 0x00 dlen 1033             #36 [hci0] 14.275753
        invalid packet size (12 != 1033)
        08 00 01 00 04 01 04 00 40 00 00 00              ........@...

Signed-off-by: Sungwoo Kim <[email protected]>
Signed-off-by: Luiz Augusto von Dentz <[email protected]>
dberlin pushed a commit to dberlin/linux that referenced this issue Nov 20, 2023
@laoar @gregkh
bpf: Fix missed rcu read lock in bpf_task_under_cgroup()
ba36bc0 
[ Upstream commit 29a7e00 ]

When employed within a sleepable program not under RCU protection, the
use of 'bpf_task_under_cgroup()' may trigger a warning in the kernel log,
particularly when CONFIG_PROVE_RCU is enabled:

  [ 1259.662357] WARNING: suspicious RCU usage
  [ 1259.662358] 6.5.0+ AsahiLinux#33 Not tainted
  [ 1259.662360] -----------------------------
  [ 1259.662361] include/linux/cgroup.h:423 suspicious rcu_dereference_check() usage!

Other info that might help to debug this:

  [ 1259.662366] rcu_scheduler_active = 2, debug_locks = 1
  [ 1259.662368] 1 lock held by trace/72954:
  [ 1259.662369]  #0: ffffffffb5e3eda0 (rcu_read_lock_trace){....}-{0:0}, at: __bpf_prog_enter_sleepable+0x0/0xb0

Stack backtrace:

  [ 1259.662385] CPU: 50 PID: 72954 Comm: trace Kdump: loaded Not tainted 6.5.0+ AsahiLinux#33
  [ 1259.662391] Call Trace:
  [ 1259.662393]  <TASK>
  [ 1259.662395]  dump_stack_lvl+0x6e/0x90
  [ 1259.662401]  dump_stack+0x10/0x20
  [ 1259.662404]  lockdep_rcu_suspicious+0x163/0x1b0
  [ 1259.662412]  task_css_set.part.0+0x23/0x30
  [ 1259.662417]  bpf_task_under_cgroup+0xe7/0xf0
  [ 1259.662422]  bpf_prog_7fffba481a3bcf88_lsm_run+0x5c/0x93
  [ 1259.662431]  bpf_trampoline_6442505574+0x60/0x1000
  [ 1259.662439]  bpf_lsm_bpf+0x5/0x20
  [ 1259.662443]  ? security_bpf+0x32/0x50
  [ 1259.662452]  __sys_bpf+0xe6/0xdd0
  [ 1259.662463]  __x64_sys_bpf+0x1a/0x30
  [ 1259.662467]  do_syscall_64+0x38/0x90
  [ 1259.662472]  entry_SYSCALL_64_after_hwframe+0x6e/0xd8
  [ 1259.662479] RIP: 0033:0x7f487baf8e29
  [...]
  [ 1259.662504]  </TASK>

This issue can be reproduced by executing a straightforward program, as
demonstrated below:

SEC("lsm.s/bpf")
int BPF_PROG(lsm_run, int cmd, union bpf_attr *attr, unsigned int size)
{
        struct cgroup *cgrp = NULL;
        struct task_struct *task;
        int ret = 0;

        if (cmd != BPF_LINK_CREATE)
                return 0;

        // The cgroup2 should be mounted first
        cgrp = bpf_cgroup_from_id(1);
        if (!cgrp)
                goto out;
        task = bpf_get_current_task_btf();
        if (bpf_task_under_cgroup(task, cgrp))
                ret = -1;
        bpf_cgroup_release(cgrp);

out:
        return ret;
}

After running the program, if you subsequently execute another BPF program,
you will encounter the warning.

It's worth noting that task_under_cgroup_hierarchy() is also utilized by
bpf_current_task_under_cgroup(). However, bpf_current_task_under_cgroup()
doesn't exhibit this issue because it cannot be used in sleepable BPF
programs.

Fixes: b5ad4cd ("bpf: Add bpf_task_under_cgroup() kfunc")
Signed-off-by: Yafang Shao <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Acked-by: Stanislav Fomichev <[email protected]>
Cc: Feng Zhou <[email protected]>
Cc: KP Singh <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
jannau pushed a commit that referenced this issue Jun 28, 2024
@gregkh
selftests/bpf: Fix flaky test btf_map_in_map/lookup_update
4a6adfe 
[ Upstream commit 14bb1e8 ]

Recently, I frequently hit the following test failure:

  [root@arch-fb-vm1 bpf]# ./test_progs -n 33/1
  test_lookup_update:PASS:skel_open 0 nsec
  [...]
  test_lookup_update:PASS:sync_rcu 0 nsec
  test_lookup_update:FAIL:map1_leak inner_map1 leaked!
  #33/1    btf_map_in_map/lookup_update:FAIL
  #33      btf_map_in_map:FAIL

In the test, after map is closed and then after two rcu grace periods,
it is assumed that map_id is not available to user space.

But the above assumption cannot be guaranteed. After zero or one
or two rcu grace periods in different siturations, the actual
freeing-map-work is put into a workqueue. Later on, when the work
is dequeued, the map will be actually freed.
See bpf_map_put() in kernel/bpf/syscall.c.

By using workqueue, there is no ganrantee that map will be actually
freed after a couple of rcu grace periods. This patch removed
such map leak detection and then the test can pass consistently.

Signed-off-by: Yonghong Song <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
jannau pushed a commit that referenced this issue Jul 11, 2024
@gregkh
jffs2: Fix potential illegal address access in jffs2_free_inode
05fc1ef 
[ Upstream commit af9a873 ]

During the stress testing of the jffs2 file system,the following
abnormal printouts were found:
[ 2430.649000] Unable to handle kernel paging request at virtual address 0069696969696948
[ 2430.649622] Mem abort info:
[ 2430.649829]   ESR = 0x96000004
[ 2430.650115]   EC = 0x25: DABT (current EL), IL = 32 bits
[ 2430.650564]   SET = 0, FnV = 0
[ 2430.650795]   EA = 0, S1PTW = 0
[ 2430.651032]   FSC = 0x04: level 0 translation fault
[ 2430.651446] Data abort info:
[ 2430.651683]   ISV = 0, ISS = 0x00000004
[ 2430.652001]   CM = 0, WnR = 0
[ 2430.652558] [0069696969696948] address between user and kernel address ranges
[ 2430.653265] Internal error: Oops: 96000004 [#1] PREEMPT SMP
[ 2430.654512] CPU: 2 PID: 20919 Comm: cat Not tainted 5.15.25-g512f31242bf6 #33
[ 2430.655008] Hardware name: linux,dummy-virt (DT)
[ 2430.655517] pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 2430.656142] pc : kfree+0x78/0x348
[ 2430.656630] lr : jffs2_free_inode+0x24/0x48
[ 2430.657051] sp : ffff800009eebd10
[ 2430.657355] x29: ffff800009eebd10 x28: 0000000000000001 x27: 0000000000000000
[ 2430.658327] x26: ffff000038f09d80 x25: 0080000000000000 x24: ffff800009d38000
[ 2430.658919] x23: 5a5a5a5a5a5a5a5a x22: ffff000038f09d80 x21: ffff8000084f0d14
[ 2430.659434] x20: ffff0000bf9a6ac0 x19: 0169696969696940 x18: 0000000000000000
[ 2430.659969] x17: ffff8000b6506000 x16: ffff800009eec000 x15: 0000000000004000
[ 2430.660637] x14: 0000000000000000 x13: 00000001000820a1 x12: 00000000000d1b19
[ 2430.661345] x11: 0004000800000000 x10: 0000000000000001 x9 : ffff8000084f0d14
[ 2430.662025] x8 : ffff0000bf9a6b40 x7 : ffff0000bf9a6b48 x6 : 0000000003470302
[ 2430.662695] x5 : ffff00002e41dcc0 x4 : ffff0000bf9aa3b0 x3 : 0000000003470342
[ 2430.663486] x2 : 0000000000000000 x1 : ffff8000084f0d14 x0 : fffffc0000000000
[ 2430.664217] Call trace:
[ 2430.664528]  kfree+0x78/0x348
[ 2430.664855]  jffs2_free_inode+0x24/0x48
[ 2430.665233]  i_callback+0x24/0x50
[ 2430.665528]  rcu_do_batch+0x1ac/0x448
[ 2430.665892]  rcu_core+0x28c/0x3c8
[ 2430.666151]  rcu_core_si+0x18/0x28
[ 2430.666473]  __do_softirq+0x138/0x3cc
[ 2430.666781]  irq_exit+0xf0/0x110
[ 2430.667065]  handle_domain_irq+0x6c/0x98
[ 2430.667447]  gic_handle_irq+0xac/0xe8
[ 2430.667739]  call_on_irq_stack+0x28/0x54
The parameter passed to kfree was 5a5a5a5a, which corresponds to the target field of
the jffs_inode_info structure. It was found that all variables in the jffs_inode_info
structure were 5a5a5a5a, except for the first member sem. It is suspected that these
variables are not initialized because they were set to 5a5a5a5a during memory testing,
which is meant to detect uninitialized memory.The sem variable is initialized in the
function jffs2_i_init_once, while other members are initialized in
the function jffs2_init_inode_info.

The function jffs2_init_inode_info is called after iget_locked,
but in the iget_locked function, the destroy_inode process is triggered,
which releases the inode and consequently, the target member of the inode
is not initialized.In concurrent high pressure scenarios, iget_locked
may enter the destroy_inode branch as described in the code.

Since the destroy_inode functionality of jffs2 only releases the target,
the fix method is to set target to NULL in jffs2_i_init_once.

Signed-off-by: Wang Yong <[email protected]>
Reviewed-by: Lu Zhongjun <[email protected]>
Reviewed-by: Yang Tao <[email protected]>
Cc: Xu Xin <[email protected]>
Cc: Yang Yang <[email protected]>
Signed-off-by: Richard Weinberger <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
jannau pushed a commit that referenced this issue Nov 19, 2024
@leitao @kuba-moo
ipmr: Fix access to mfc_cache_list without lock held
e28acc9 
Accessing `mr_table->mfc_cache_list` is protected by an RCU lock. In the
following code flow, the RCU read lock is not held, causing the
following error when `RCU_PROVE` is not held. The same problem might
show up in the IPv6 code path.

	6.12.0-rc5-kbuilder-01145-gbac17284bdcb #33 Tainted: G            E    N
	-----------------------------
	net/ipv4/ipmr_base.c:313 RCU-list traversed in non-reader section!!

	rcu_scheduler_active = 2, debug_locks = 1
		   2 locks held by RetransmitAggre/3519:
		    #0: ffff88816188c6c0 (nlk_cb_mutex-ROUTE){+.+.}-{3:3}, at: __netlink_dump_start+0x8a/0x290
		    #1: ffffffff83fcf7a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_dumpit+0x6b/0x90

	stack backtrace:
		    lockdep_rcu_suspicious
		    mr_table_dump
		    ipmr_rtm_dumproute
		    rtnl_dump_all
		    rtnl_dumpit
		    netlink_dump
		    __netlink_dump_start
		    rtnetlink_rcv_msg
		    netlink_rcv_skb
		    netlink_unicast
		    netlink_sendmsg

This is not a problem per see, since the RTNL lock is held here, so, it
is safe to iterate in the list without the RCU read lock, as suggested
by Eric.

To alleviate the concern, modify the code to use
list_for_each_entry_rcu() with the RTNL-held argument.

The annotation will raise an error only if RTNL or RCU read lock are
missing during iteration, signaling a legitimate problem, otherwise it
will avoid this false positive.

This will solve the IPv6 case as well, since ip6mr_rtm_dumproute() calls
this function as well.

Signed-off-by: Breno Leitao <[email protected]>
Reviewed-by: David Ahern <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
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