Issue

• The exact cause of the panic can be any of the following:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000ce8
  
  general protection fault: 0000 [#1] SMP
  
  BUG: unable to handle kernel paging request at 0000000100000000
  

• Example stack trace from client panic with BUG: unable to handle kernel NULL pointer dereference at 0000000000000ce8:

  crash> bt
  PID: 75420  TASK: ffff9f24bfb46eb0  CPU: 26  COMMAND: "mount.nfs"
   #0 [ffff9f343d69b880] machine_kexec at ffffffffa58629da
   #1 [ffff9f343d69b8e0] __crash_kexec at ffffffffa5916692
   #2 [ffff9f343d69b9b0] crash_kexec at ffffffffa5916780
   #3 [ffff9f343d69b9c8] oops_end at ffffffffa5f1d728
   #4 [ffff9f343d69b9f0] no_context at ffffffffa5f0c6cd
   #5 [ffff9f343d69ba40] __bad_area_nosemaphore at ffffffffa5f0c764
   #6 [ffff9f343d69ba90] bad_area at ffffffffa5f0ca74
   #7 [ffff9f343d69bab8] __do_page_fault at ffffffffa5f2088f
   #8 [ffff9f343d69bb20] do_page_fault at ffffffffa5f208d5
   #9 [ffff9f343d69bb50] page_fault at ffffffffa5f1c758
      [exception RIP: lockd_down_net+23]
      RIP: ffffffffc0ae1067  RSP: ffff9f343d69bc08  RFLAGS: 00010202
      RAX: 0000000000000008  RBX: 0000000000000000  RCX: ffff9f343d69bfd8
      RDX: 0000000000000000  RSI: 0000000000000000  RDI: ffff9f302ba0c200
      RBP: ffff9f343d69bc18   R8: 000000000001bb00   R9: ffffffffc0aff64b
      R10: ffff9f4f41a9bb00  R11: ffffe440735e8280  R12: ffff9f4d97a0a700
      R13: ffffffffffffffea  R14: ffff9f343d69bdb0  R15: ffffffffc0bde000
      ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
  #10 [ffff9f343d69bc20] lockd_down at ffffffffc0ae112f [lockd]
  #11 [ffff9f343d69bc38] nlmclnt_done at ffffffffc0add0de [lockd]
  #12 [ffff9f343d69bc50] nfs_destroy_server at ffffffffc0afd627 [nfs]
  #13 [ffff9f343d69bc60] nfs_free_server at ffffffffc0afe386 [nfs]
  #14 [ffff9f343d69bc78] nfs_create_server at ffffffffc0aff653 [nfs]
  #15 [ffff9f343d69bcb0] nfs3_create_server at ffffffffc0bd617f [nfsv3]
  #16 [ffff9f343d69bcc8] nfs_try_mount at ffffffffc0b0c891 [nfs]
  #17 [ffff9f343d69bd88] nfs_fs_mount at ffffffffc0b0bcdb [nfs]
  #18 [ffff9f343d69be10] mount_fs at ffffffffa5a23c2e
  #19 [ffff9f343d69be58] vfs_kern_mount at ffffffffa5a41157
  #20 [ffff9f343d69be90] do_mount at ffffffffa5a4377f
  #21 [ffff9f343d69bf18] sys_mount at ffffffffa5a445b3
  #22 [ffff9f343d69bf50] system_call_fastpath at ffffffffa5f2579b
      RIP: 00007f4249d3629a  RSP: 00007ffc231e07e8  RFLAGS: 00000216
      RAX: 00000000000000a5  RBX: 0000000000000000  RCX: ffffffffffffffff
      RDX: 000056456582b280  RSI: 000056456582b490  RDI: 000056456582b420
      RBP: 00007ffc231e0a70   R8: 000056456582e130   R9: 000000000000004d
      R10: 0000000000000000  R11: 0000000000000246  R12: 00007f424a67f7e0
      R13: 00007ffc231e0a70  R14: 00007ffc231e0950  R15: 000056456582e110
      ORIG_RAX: 00000000000000a5  CS: 0033  SS: 002b