On 18.10.2013 06:06, Wangyufei (A) wrote: > Thanks at first, this patch some kinda solve my problem until now. But I still have a doubt about this patch. > >> -----Original Message----- >> From: libvir-list-bounces@xxxxxxxxxx >> [mailto:libvir-list-bounces@xxxxxxxxxx] On Behalf Of Michal Privoznik >> Sent: Friday, October 11, 2013 8:15 PM >> To: libvir-list@xxxxxxxxxx >> Subject: [PATCH v2] qemu_migration: Avoid crashing if domain dies >> too quickly >> @@ -2673,6 +2677,8 @@ cleanup: >> virCommandFree(cmd); >> VIR_FREE(monarg); >> VIR_FREE(monpath); >> + virObjectUnref(vm); > > Is this virObjectUnref(vm) corresponding to mon->vm = virObjectRef(vm) added in qemuMonitorOpenInternal? > If it is, how can we confirm virObjectRef(vm) has been done in qemuMonitorOpenInternal? If an error (anyone follows)happened in qemuMonitorOpenInternal is before mon->vm = virObjectRef(vm), > then we still goto cleanup and do virObjectUnref(vm), the refs will be wrong. Am I right? > Unfortunately, you've cut off the chunk above that allocates @mon. Anyway, on initialization, @mon is filled with zeros. So until somebody sets mon->vm [1] mon->vm is effectively NULL. And virObjectUnref() acts like NOP on NULL. > if (!cb->eofNotify) { > virReportError(VIR_ERR_INTERNAL_ERROR, "%s", > _("EOF notify callback must be supplied")); > return NULL; > } > if (!cb->errorNotify) { > virReportError(VIR_ERR_INTERNAL_ERROR, "%s", > _("Error notify callback must be supplied")); > return NULL; > } > > if (qemuMonitorInitialize() < 0) > return NULL; > > if (!(mon = virObjectLockableNew(qemuMonitorClass))) > return NULL; > > mon->fd = -1; > mon->logfd = -1; > if (virCondInit(&mon->notify) < 0) { > virReportError(VIR_ERR_INTERNAL_ERROR, "%s", > _("cannot initialize monitor condition")); > goto cleanup; > } > mon->fd = fd; > mon->hasSendFD = hasSendFD; > mon->vm = virObjectRef(vm); 1: ^^ until after this line > >> + virObjectUnref(xmlopt); >> >> if (pid != 0) { >> char ebuf[1024]; I hope it makes things a bit clearer. Michal -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list