Re: [libvirt] libvirtd deadlock on shutdown

I'm looking into a libvirtd deadlock on daemon shutdown. The deadlock occurs when shutting down virNetServer. If the handling of a job is in flight in virNetServerHandleJob(), the virNetServer lock is acquired when freeing job->prog (src/rpc/virnetserver.c:167). But the lock is already held in virNetServerFree(), which is blocked in virThreadPoolFree() waiting for all the workers to finish. No progress can be made. The attached hack fixes the problem, but I'm not convinced this is an appropriate fix. Is it necessary to hold the virNetServer lock when calling virNetServerProgramFree(job->prog)? I notice the lock is not held in the error path of virNetServerHandleJob().

+++ b/src/rpc/virnetserver.c @@ -774,7 +774,9 @@ void virNetServerFree(virNetServerPtr srv) for (i = 0 ; i < srv->nservices ; i++) virNetServerServiceToggle(srv->services[i], false); + virNetServerUnlock(srv); virThreadPoolFree(srv->workers); + virNetServerLock(srv);