Issue

• The system got crashed with following error messages on console, when there was some issue in one of the FC fabric:

  qla2xxx [0000:21:00.1]-801c:4: Abort command issued nexus=4:1:0 --  1 2002.
  qla2xxx [0000:21:00.1]-8018:4: ADAPTER RESET ISSUED nexus=4:1:0.
  qla2xxx [0000:21:00.1]-00af:4: Performing ISP error recovery - ha=ffff88102c3a2000.
  qla2xxx [0000:21:00.1]-8017:4: ADAPTER RESET SUCCEEDED nexus=4:1:0.
  scsi 4:0:1:0: Device offlined - not ready after error recovery
   rport-4:0-2: blocked FC remote port time out: removing target and saving binding
  BUG: unable to handle kernel NULL pointer dereference at 0000000000000320
  IP: [<ffffffff81257482>] blk_cleanup_queue+0x12/0x150
  PGD 0 
  Oops: 0000 [#1] SMP 
  last sysfs file: /sys/devices/pci0000:00/0000:00:02.0/0000:04:00.7/device
  CPU 24 
  [...]
  Process fc_wq_4 (pid: 910, threadinfo ffff880826210000, task ffff8808261d4080)
  Stack:
   0000000000000000 ffff88102c343800 ffff88102c343938 ffff88102c343800
  <d> ffff880826211d40 ffffffff8137111d ffff88102c399860 ffff88102c343800
  <d> ffff880826211d60 ffffffff81371190 ffff88102c399800 ffff88102bc55800
  Call Trace:
   [<ffffffff8137111d>] __scsi_remove_device+0x7d/0xc0
   [<ffffffff81371190>] scsi_remove_device+0x30/0x50
   [<ffffffff8137127d>] __scsi_remove_target+0xad/0xe0
   [<ffffffff81371320>] ? __remove_child+0x0/0x30
   [<ffffffff81371343>] __remove_child+0x23/0x30
   [<ffffffff8134c3bc>] device_for_each_child+0x4c/0x80
   [<ffffffffa0069010>] ? fc_starget_delete+0x0/0x30 [scsi_transport_fc]
   [<ffffffff813712ee>] scsi_remove_target+0x3e/0x70
   [<ffffffffa0069036>] fc_starget_delete+0x26/0x30 [scsi_transport_fc]
   [<ffffffff8108c760>] worker_thread+0x170/0x2a0
   [<ffffffff810920d0>] ? autoremove_wake_function+0x0/0x40
   [<ffffffff8108c5f0>] ? worker_thread+0x0/0x2a0
   [<ffffffff81091d66>] kthread+0x96/0xa0
   [<ffffffff8100c14a>] child_rip+0xa/0x20
   [<ffffffff81091cd0>] ? kthread+0x0/0xa0
   [<ffffffff8100c140>] ? child_rip+0x0/0x20
  Code: 21 64 d7 00 01 00 00 00 eb c5 66 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 41 55 41 54 53 48 83 ec 08 0f 1f 44 00 00 <4c> 8b af 20 03 00 00 4c 8d a7 b8 08 00 00 48  89 fb 4c 89 e7 e8 
  RIP  [<ffffffff81257482>] blk_cleanup_queue+0x12/0x150
   RSP <ffff880826211d00>
  CR2: 0000000000000320