Issue

• System crashes with kernel panic and dumps the vmcore.
• Kernel BUG at fs/locks.c:175

• crash> bt
  PID: 2536   TASK: ffff810107201080  CPU: 3   COMMAND: "nfsd"
  #0 [ffff8101f20b3410] crash_kexec at ffffffff800acd70
  #1 [ffff8101f20b34d0] __die at ffffffff80065127
  #2 [ffff8101f20b3510] die at ffffffff8006bc5d
  #3 [ffff8101f20b3540] do_invalid_op at ffffffff8006c21d
  #4 [ffff8101f20b3600] error_exit at ffffffff8005dde9
      [exception RIP: locks_free_lock+34]
      RIP: ffffffff8003fbb8  RSP: ffff8101f20b36b0  RFLAGS: 00010287
      RAX: ffff81010b903570  RBX: ffff81010b903558  RCX: 0000000000000000
      RDX: ffff810107201080  RSI: 0000000000000000  RDI: ffff81010b903558
      RBP: ffff8101ffb1bc38   R8: 0000000000000000   R9: 7fffffffffffffff
      R10: 0000000000000001  R11: 00000000000003e9  R12: 0000000000000004
      R13: ffff81010b903558  R14: 0000000000000000  R15: 0000000000000800
      ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
  #5 [ffff8101f20b36b8] __break_lease at ffffffff800e95fb
  #6 [ffff8101f20b3748] nfsd_open at ffffffff8848cd56
  #7 [ffff8101f20b3788] nfsd4_process_open2 at ffffffff884a0c9e
  #8 [ffff8101f20b3908] nfsd4_proc_compound at ffffffff8849884f
  #9 [ffff8101f20b3ea8] __down_read at ffffffff80064614
  #10 [ffff8101f20b3ee8] nfsd at ffffffff88489746
  #11 [ffff8101f20b3f48] kernel_thread at ffffffff8005dfb1

• crash> bt
  PID: 17051  TASK: ffff8101a17e8040  CPU: 0   COMMAND: "top"
  #0 [ffff810194f1fba0] crash_kexec at ffffffff800ad9ce
  #1 [ffff810194f1fc60] __die at ffffffff80065157
  #2 [ffff810194f1fca0] die at ffffffff8006bcc7
  #3 [ffff810194f1fcd0] do_invalid_op at ffffffff8006c287
  #4 [ffff810194f1fd90] error_exit at ffffffff8005dde9
      [exception RIP: locks_free_lock+34]
      RIP: ffffffff8003fbc2  RSP: ffff810194f1fe48  RFLAGS: 00010202
      RAX: ffff810302de9570  RBX: ffff810302de9558  RCX: 0000000000000000
      RDX: ffff8101a17e8040  RSI: ffffffff80319910  RDI: ffff810302de9558
      RBP: ffff810319aba818   R8: ffff810319aba818   R9: ffff81010b6f0000
      R10: 0000000000000008  R11: 000000d0ffffffff  R12: 0000000000000001
      R13: 0000000000000000  R14: ffff81033918cdf0  R15: 0000000000000000
      ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
  #5 [ffff810194f1fe50] __posix_lock_file_conf at ffffffff800ea84a
  #6 [ffff810194f1feb0] fcntl_setlk at ffffffff80039e19
  #7 [ffff810194f1ff50] sys_fcntl at ffffffff8002e508
  #8 [ffff810194f1ff80] tracesys at ffffffff8005d28d (via system_call)
      RIP: 0000003f266c6789  RSP: 00007fffda568538  RFLAGS: 00000206
      RAX: ffffffffffffffda  RBX: ffffffff8005d28d  RCX: ffffffffffffffff
      RDX: 00007fffda5686e0  RSI: 0000000000000007  RDI: 0000000000000007
      RBP: 000000000ad5e430   R8: 00007fffda568640   R9: 00007fffda5685a0
      R10: 0000000000000008  R11: 0000000000000206  R12: 0000000000000000
      R13: 00007fffda5686e0  R14: 00007fffda568760  R15: 0000000000000000
      ORIG_RAX: 0000000000000048  CS: 0033  SS: 002b