Failed to terminate process 1901409 with SIGKILL: Device or resource busy

Hi All, I hit another issue that libvirt sometimes throw exception like 'Failed to terminate process 1901409 with SIGKILL: Device or resource busy’ once we try to destroy vm through 'conn.lookupByID(id_).destroy()’. After this issue occur, it will caused the socket fd and pipe increased and finally caused fd leak. Who know the root cause of this issue or give some cues? Any comments are appreciated Thanks !