qemu: Don't unref domain after exit from nested async job

In commit 540c339a2535ec30d79e5ef84d8f50a17bc60723 the whole domain
reference counting was refactored in the qemu driver. Domain jobs now
don't need to reference the domain object as they now expect the
reference from the calling function.

However, the patch forgot to remove the unref call in case we exit the
monitor when we were acquiring a nested job. This caused the daemon to
crash on a subsequent access to the domain object once we've done an
operation requiring a nested job for a monitor access.

An easy reproducer case:

1) Start a vm with qcow disks
2) virsh snapshot-create-as DOMNAME
3) virsh dumpxml DOMNAME
4) daemon crashes in a semi-random spot while accessing a now-removed VM
object.

Fortunately, the commit wasn't released yet, so there are no security
implications.

Reported-by: Shanzi Yu <shyu@redhat.com>
Signed-off-by: Peter Krempa <pkrempa@redhat.com>

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index bd64409edc6c54c4b0eb340005efc9bb4a7f90a4..3d4023c6c891c4ee55a2679c09427e242923597f 100644 (file)
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -1573,8 +1573,6 @@ qemuDomainObjExitMonitorInternal(virQEMUDriverPtr driver,
         qemuDomainObjResetJob(priv);
         qemuDomainObjSaveJob(driver, obj);
         virCondSignal(&priv->job.cond);
-
-        virObjectUnref(obj);
     }
 }