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vmxnet3: avoid calling pskb_may_pull with interrupts disabled
vmxnet3 has a function vmxnet3_parse_and_copy_hdr which, among other operations, uses pskb_may_pull to linearize the header portion of an skb. That operation eventually uses local_bh_disable/enable to ensure that it doesn't race with the drivers bottom half handler. Unfortunately, vmxnet3 preforms this parse_and_copy operation with a spinlock held and interrupts disabled. This causes us to run afoul of the WARN_ON_ONCE(irqs_disabled()) warning in local_bh_enable, resulting in this: WARNING: at kernel/softirq.c:159 local_bh_enable+0x59/0x90() (Not tainted) Hardware name: VMware Virtual Platform Modules linked in: ipv6 ppdev parport_pc parport microcode e1000 vmware_balloon vmxnet3 i2c_piix4 sg ext4 jbd2 mbcache sd_mod crc_t10dif sr_mod cdrom mptspi mptscsih mptbase scsi_transport_spi pata_acpi ata_generic ata_piix vmwgfx ttm drm_kms_helper drm i2c_core dm_mirror dm_region_hash dm_log dm_mod [last unloaded: mperf] Pid: 6229, comm: sshd Not tainted 2.6.32-616.el6.i686 #1 Call Trace: [<c04624d9>] ? warn_slowpath_common+0x89/0xe0 [<c0469e99>] ? local_bh_enable+0x59/0x90 [<c046254b>] ? warn_slowpath_null+0x1b/0x20 [<c0469e99>] ? local_bh_enable+0x59/0x90 [<c07bb936>] ? skb_copy_bits+0x126/0x210 [<f8d1d9fe>] ? ext4_ext_find_extent+0x24e/0x2d0 [ext4] [<c07bc49e>] ? __pskb_pull_tail+0x6e/0x2b0 [<f95a6164>] ? vmxnet3_xmit_frame+0xba4/0xef0 [vmxnet3] [<c05d15a6>] ? selinux_ip_postroute+0x56/0x320 [<c0615988>] ? cfq_add_rq_rb+0x98/0x110 [<c0852df8>] ? packet_rcv+0x48/0x350 [<c07c5839>] ? dev_queue_xmit_nit+0xc9/0x140 ... Fix it by splitting vmxnet3_parse_and_copy_hdr into two functions: vmxnet3_parse_hdr, which sets up the internal/on stack ctx datastructure, and pulls the skb (both of which can be done without holding the spinlock with irqs disabled and vmxnet3_copy_header, which just copies the skb to the tx ring under the lock safely. tested and shown to correct the described problem. Applies cleanly to the head of the net tree Signed-off-by: Neil Horman <[email protected]> CC: Shrikrishna Khare <[email protected]> CC: "VMware, Inc." <[email protected]> CC: "David S. Miller" <[email protected]> Acked-by: Shrikrishna Khare <[email protected]> Signed-off-by: David S. Miller <[email protected]>
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