scsi: bnx2fc: fix race condition in bnx2fc_get_host_stats()
[ Upstream commit c2dd893a3b0772d1c680e109b9d5715d7f73022b ]
If multiple tasks attempt to read the stats, it may happen that the
start_req_done completion is re-initialized while still being used by
another task, causing a list corruption.
This patch fixes the bug by adding a mutex to serialize the calls to
bnx2fc_get_host_stats().
WARNING: at lib/list_debug.c:48 list_del+0x6e/0xa0() (Not tainted)
Hardware name: PowerEdge R820
list_del corruption. prev->next should be ffff882035627d90, but was ffff884069541588
Pid: 40267, comm: perl Not tainted 2.6.32-642.3.1.el6.x86_64 #1
Call Trace:
[<ffffffff8107c691>] ? warn_slowpath_common+0x91/0xe0
[<ffffffff8107c796>] ? warn_slowpath_fmt+0x46/0x60
[<ffffffff812ad16e>] ? list_del+0x6e/0xa0
[<ffffffff81547eed>] ? wait_for_common+0x14d/0x180
[<ffffffff8106c4a0>] ? default_wake_function+0x0/0x20
[<ffffffff81547fd3>] ? wait_for_completion_timeout+0x13/0x20
[<ffffffffa05410b1>] ? bnx2fc_get_host_stats+0xa1/0x280 [bnx2fc]
[<ffffffffa04cf630>] ? fc_stat_show+0x90/0xc0 [scsi_transport_fc]
[<ffffffffa04cf8b6>] ? show_fcstat_tx_frames+0x16/0x20 [scsi_transport_fc]
[<ffffffff8137c647>] ? dev_attr_show+0x27/0x50
[<ffffffff8113b9be>] ? __get_free_pages+0xe/0x50
[<ffffffff812170e1>] ? sysfs_read_file+0x111/0x200
[<ffffffff8119a305>] ? vfs_read+0xb5/0x1a0
[<ffffffff8119b0b6>] ? fget_light_pos+0x16/0x50
[<ffffffff8119a651>] ? sys_read+0x51/0xb0
[<ffffffff810ee1fe>] ? __audit_syscall_exit+0x25e/0x290
[<ffffffff8100b0d2>] ? system_call_fastpath+0x16/0x1b
Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
Acked-by: Chad Dupuis <chad.dupuis@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2 files changed