diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 7ff846f6f6..0d3b0bd7f3 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -9919,7 +9919,7 @@ qemuDomainSnapshotCreateSingleDiskActive(struct qemud_driver *driver,
 
     /* create the actual snapshot */
     ret = qemuMonitorDiskSnapshot(priv->mon, actions, device, source,
-                                  driverType, reuse);
+                                  snap->driverType, reuse);
     virDomainAuditDisk(vm, disk->src, source, "snapshot", ret >= 0);
     if (ret < 0)
         goto cleanup;
diff --git a/src/qemu/qemu_monitor_json.c b/src/qemu/qemu_monitor_json.c
index eeeb6a603b..8c028b9bc0 100644
--- a/src/qemu/qemu_monitor_json.c
+++ b/src/qemu/qemu_monitor_json.c
@@ -417,6 +417,12 @@ qemuMonitorJSONMakeCommandRaw(bool wrap, const char *cmdname, ...)
         switch (type) {
         case 's': {
             char *val = va_arg(args, char *);
+            if (!val) {
+                qemuReportError(VIR_ERR_INTERNAL_ERROR,
+                                _("argument key '%s' must not have null value"),
+                                key);
+                goto error;
+            }
             ret = virJSONValueObjectAppendString(jargs, key, val);
         }   break;
         case 'i': {