--- x/kernel/vhost_task.c
+++ y/kernel/vhost_task.c
@@ -100,6 +100,8 @@ void vhost_task_stop(struct vhost_task *
 	 * freeing it below.
 	 */
 	wait_for_completion(&vtsk->exited);
+	mutex_lock(&vtsk->exit_mutex);
+	mutex_unlock(&vtsk->exit_mutex);
 	kfree(vtsk);
 }
 EXPORT_SYMBOL_GPL(vhost_task_stop);