segfault occurs with nbd-server process. How to find the root cause?

Issue

• segfault occurs with nbd-server process. How to find the root cause?
  Sample log

  kernel: nbd-server[15300]: segfault at 00000000082d20f8 rip 00000000009f06d1 rsp 000000005577d2e4 error 4
  

  When this messages logged, another node might have I/O error in /var/log/messages like

  kernel: nbd17: Receive control failed (result -104)
  kernel: nbd17: shutting down socket
  kernel: end_request: I/O error, dev nbd17, sector 83328128
  kernel: raid1: Disk failure on nbd17, disabling device. 
  kernel:   Operation continuing on 1 devices
  kernel: end_request: I/O error, dev nbd17, sector 83328112
  kernel: end_request: I/O error, dev nbd17, sector 140966752
  kernel: end_request: I/O error, dev nbd17, sector 107277384
  kernel: end_request: I/O error, dev nbd17, sector 89877648