On 12.11.2020 20:12, Michal Privoznik wrote: > On 4/27/20 5:54 PM, Daniel P. Berrangé wrote: >> We got a new BZ filed about a libvirtd crash in shutdown >> >> https://bugzilla.redhat.com/show_bug.cgi?id=1828207 > > And there is another one: > > https://bugzilla.redhat.com/show_bug.cgi?id=1895359 > > The problem is that when host is shutting down we get PrepareForShutdown() > signal on dbus and spawn a thread that will eventually call qemuStateStop(). > But before it gets a chance to run the main thread quits the event loop and > calls qemuStateCleanup() freeing the qemu driver. After all this the dbus > signal handling thread gets to run only to find qemu_driver=0x0 and thus > crash. > > From the fact that the event loop quit I deduct that we were sent a SIGTERM > which means there was no guest running otherwise we would inhibit the > shutdown, so qemuStateStop() would be a NOP anyway. So maybe the fix for this > particular case indeed is to check whether qemu_driver == 0x0. > > Anyway, I think your idea is sound. > Hi, Michal. I added code to handle shutdown as Dan proposed in [1]. It handles most busy threads which are rpc and worker and per-VM event loop threads in qemu driver. But there are still other drivers and short living threads here and there [2]. So thread that spawns daemonStop is on of these untamed threads. So we need to join this thread in daemonShutdownWait. [1] [PATCH v2 00/13] resolve hangs/crashes on libvirtd shutdown https://www.redhat.com/archives/libvir-list/2020-July/msg01606.html [2] Re: [PATCH v2 00/13] resolve hangs/crashes on libvirtd shutdown https://www.redhat.com/archives/libvir-list/2020-September/msg00319.html Nikolay
