[libvirt] [PATCH 1/2] avoid vm is deleted in qemuDomainMigrateConfirm3()

[Wen Congyang]

If we use p2p migration and the vm is transient, vm will be deleted in
qemuDomainMigrateConfirm3(). But the caller(doPeer2PeerMigrate() and
qemuMigrationPerform()) still access it, and it will cause libvirtd crashed.

---
 src/qemu/qemu_migration.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
index 4d7bc38..ab28416 100644
--- a/src/qemu/qemu_migration.c
+++ b/src/qemu/qemu_migration.c
@@ -1971,6 +1971,11 @@ int qemuMigrationPerform(struct qemud_driver *driver,
         goto cleanup;
     priv->jobActive = QEMU_JOB_MIGRATION_OUT;
 
+    /* Hold an extra reference because we can't allow 'vm' to be deleted in
+     * qemuDomainMigrateConfirm3().
+     */
+    virDomainObjRef(vm);
+
     if (!virDomainObjIsActive(vm)) {
         qemuReportError(VIR_ERR_OPERATION_INVALID,
                         "%s", _("domain is not running"));
@@ -2045,7 +2050,7 @@ endjob:
         vm = NULL;
 
 cleanup:
-    if (vm)
+    if (vm && virDomainObjUnref(vm) > 0)
         virDomainObjUnlock(vm);
     if (event)
         qemuDomainEventQueue(driver, event);
-- 
1.7.1