qemu: Don't leak domain def when RevertToSnapshot fails

Once we copy the domain definition from virDomainSnapshotDef, we either
need to assign it to the domain object or free it to avoid memory leaks.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NPavel Hrdina <phrdina@redhat.com>

src/qemu/qemu_driver.c

@@ -16568,6 +16568,7 @@ qemuDomainRevertToSnapshot(virDomainSnapshotPtr snapshot,
     virCPUDefPtr origCPU = NULL;
     unsigned int start_flags = VIR_QEMU_PROCESS_START_GEN_VMID;
     qemuDomainAsyncJob jobType = QEMU_ASYNC_JOB_START;
+    bool defined = false;
 
     virCheckFlags(VIR_DOMAIN_SNAPSHOT_REVERT_RUNNING |
                   VIR_DOMAIN_SNAPSHOT_REVERT_PAUSED |
@@ -16779,6 +16780,8 @@ qemuDomainRevertToSnapshot(virDomainSnapshotPtr snapshot,
                 virDomainObjAssignDef(vm, config, false, NULL);
                 virCPUDefFree(priv->origCPU);
                 VIR_STEAL_PTR(priv->origCPU, origCPU);
+                config = NULL;
+                defined = true;
             }
 
             if (cookie && !cookie->slirpHelper)
@@ -16788,8 +16791,11 @@ qemuDomainRevertToSnapshot(virDomainSnapshotPtr snapshot,
             /* Transitions 2, 3 */
         load:
             was_stopped = true;
-            if (config)
+            if (config) {
                 virDomainObjAssignDef(vm, config, false, NULL);
+                config = NULL;
+                defined = true;
+            }
 
             /* No cookie means libvirt which saved the domain was too old to
              * mess up the CPU definitions.
@@ -16875,8 +16881,11 @@ qemuDomainRevertToSnapshot(virDomainSnapshotPtr snapshot,
             qemuProcessEndJob(driver, vm);
             goto cleanup;
         }
-        if (config)
+        if (config) {
             virDomainObjAssignDef(vm, config, false, NULL);
+            config = NULL;
+            defined = true;
+        }
 
         if (flags & (VIR_DOMAIN_SNAPSHOT_REVERT_RUNNING |
                      VIR_DOMAIN_SNAPSHOT_REVERT_PAUSED)) {
@@ -16942,7 +16951,7 @@ qemuDomainRevertToSnapshot(virDomainSnapshotPtr snapshot,
             ret = -1;
         }
     }
-    if (ret == 0 && config && vm->persistent &&
+    if (ret == 0 && defined && vm->persistent &&
         !(ret = virDomainSaveConfig(cfg->configDir, driver->caps,
                                     vm->newDef ? vm->newDef : vm->def))) {
         detail = VIR_DOMAIN_EVENT_DEFINED_FROM_SNAPSHOT;
@@ -16958,6 +16967,7 @@ qemuDomainRevertToSnapshot(virDomainSnapshotPtr snapshot,
     virObjectUnref(cfg);
     virNWFilterUnlockFilterUpdates();
     virCPUDefFree(origCPU);
+    virDomainDefFree(config);
 
     return ret;
 }