Issue

• Kernel crash on concurrent access to IBM 3592 tapes with lin_tape driver

• The system was crashed while attempting concurrent IO operation on tape devices using lin_tape driver. At the time of system crash, following error messages were logged on system console:

  lin_tape: tape_send_scsi_io entry
  lin_tape: tape_execute_scsi_command entry: 0x5f
  general protection fault: 0000 [#1] SMP 
  last sysfs file: /sys/module/sg/initstate
  CPU 8 
  [...]
  Process mt (pid: 5548, threadinfo ffff881509814000, task ffff8815a4905540)
  Stack:
   dead000000200200 ffff88204f4a3428 ffff881509815818 ffff8813de224b60
  <d> ffff881509815828 0000000000000008 0000000000000001 ffff8818c110e7a0
  <d> ffff8818c110e7a0 0000000000000000 0000000000000000 00000000000000ff
  Call Trace:
   [<ffffffff811b9619>] bio_free_map_data+0x19/0x40
   [<ffffffff811ba36e>] bio_uncopy_user+0x5e/0x80
   [<ffffffff8126244b>] __blk_rq_unmap_user+0x1b/0x30
   [<ffffffff81262491>] blk_rq_unmap_user+0x31/0x70
   [<ffffffffa0486e6e>] lin_tape_blk_rq+0x4de/0x560 [lin_tape]
   [<ffffffffa0486f38>] tape_execute_scsi_command+0x48/0xc0 [lin_tape]
   [<ffffffffa048c30f>] tape_send_scsi_io+0x1ff/0x490 [lin_tape]
   [<ffffffff8106ecff>] ? release_console_sem+0x1cf/0x220
  [...]