Fix vmdef usage while in monitor in qemu process

Make local copy of the disk alias in qemuProcessInitPasswords,
instead of referencing the one in domain definition, which
might get freed if the domain crashes while we're in monitor.

Also copy the memballoon period value.

src/qemu/qemu_process.c

@@ -2584,6 +2584,8 @@ qemuProcessInitPasswords(virConnectPtr conn,
     qemuDomainObjPrivatePtr priv = vm->privateData;
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
     size_t i;
+    char *alias = NULL;
+    char *secret = NULL;
 
     for (i = 0; i < vm->def->ngraphics; ++i) {
         virDomainGraphicsDefPtr graphics = vm->def->graphics[i];
@@ -2607,33 +2609,34 @@ qemuProcessInitPasswords(virConnectPtr conn,
 
     if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DEVICE)) {
         for (i = 0; i < vm->def->ndisks; i++) {
-            char *secret;
             size_t secretLen;
-            const char *alias;
 
             if (!vm->def->disks[i]->src->encryption ||
                 !virDomainDiskGetSource(vm->def->disks[i]))
                 continue;
 
+            VIR_FREE(secret);
             if (qemuProcessGetVolumeQcowPassphrase(conn,
                                                    vm->def->disks[i],
                                                    &secret, &secretLen) < 0)
                 goto cleanup;
 
-            alias = vm->def->disks[i]->info.alias;
-            if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) < 0) {
-                VIR_FREE(secret);
+            VIR_FREE(alias);
+            if (VIR_STRDUP(alias, vm->def->disks[i]->info.alias) < 0)
+                goto cleanup;
+            if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) < 0)
                 goto cleanup;
-            }
             ret = qemuMonitorSetDrivePassphrase(priv->mon, alias, secret);
-            VIR_FREE(secret);
-            qemuDomainObjExitMonitor(driver, vm);
+            if (qemuDomainObjExitMonitor(driver, vm) < 0)
+                ret = -1;
             if (ret < 0)
                 goto cleanup;
         }
     }
 
  cleanup:
+    VIR_FREE(alias);
+    VIR_FREE(secret);
     virObjectUnref(cfg);
     return ret;
 }
@@ -4258,6 +4261,7 @@ int qemuProcessStart(virConnectPtr conn,
     virCommandPtr cmd = NULL;
     struct qemuProcessHookData hookData;
     unsigned long cur_balloon;
+    unsigned int period = 0;
     size_t i;
     bool rawio_set = false;
     char *nodeset = NULL;
@@ -4870,15 +4874,18 @@ int qemuProcessStart(virConnectPtr conn,
                        vm->def->mem.cur_balloon);
         goto cleanup;
     }
+    if (vm->def->memballoon && vm->def->memballoon->period)
+        period = vm->def->memballoon->period;
     if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) < 0)
         goto cleanup;
-    if (vm->def->memballoon && vm->def->memballoon->period)
-        qemuMonitorSetMemoryStatsPeriod(priv->mon, vm->def->memballoon->period);
+    if (period)
+        qemuMonitorSetMemoryStatsPeriod(priv->mon, period);
     if (qemuMonitorSetBalloon(priv->mon, cur_balloon) < 0) {
         qemuDomainObjExitMonitor(driver, vm);
         goto cleanup;
     }
-    qemuDomainObjExitMonitor(driver, vm);
+    if (qemuDomainObjExitMonitor(driver, vm) < 0)
+        goto cleanup;
 
     VIR_DEBUG("Detecting actual memory size for video device");
     if (qemuProcessUpdateVideoRamSize(driver, vm, asyncJob) < 0)