Re: [libvirt] [PATCH] Avoid invoking the qemu monitor destroy callback if the constructor fails
diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c
index f428665..ff613a0 100644
--- a/src/qemu/qemu_monitor.c
+++ b/src/qemu/qemu_monitor.c
@@ -671,6 +671,12 @@ qemuMonitorOpen(virDomainObjPtr vm,
return mon;
cleanup:
+ /* We don't want the 'destroy' callback invoked during
+ * cleanup from construction failure, because that can
+ * give a double-unref on virDomainObjPtr in the caller,
+ * so kill the callbacks now.
+ */
+ mon->cb = NULL;
qemuMonitorUnlock(mon);
qemuMonitorClose(mon);
return NULL;
Unfortunately, this patch causes segfaults since qemuMonitorFree is not ready
to see mon->cb == NULL. On the other hand, we are lucky that this patch didn't
make it into the repository yet, so we can squash the following patch into it
before pushing:
diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c
index f428665..9b050a0 100644
--- a/src/qemu/qemu_monitor.c
+++ b/src/qemu/qemu_monitor.c
@@ -198,7 +198,7 @@ void qemuMonitorUnlock(qemuMonitorPtr mon)
static void qemuMonitorFree(qemuMonitorPtr mon)
{
VIR_DEBUG("mon=%p", mon);
- if (mon->cb->destroy)
+ if (mon->cb && mon->cb->destroy)
(mon->cb->destroy)(mon, mon->vm);
if (virCondDestroy(&mon->notify) < 0)
{}
Jirka