diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
index aea13ec..14376eb 100644
--- a/include/linux/pid_namespace.h
+++ b/include/linux/pid_namespace.h
@@ -21,6 +21,8 @@
 	int last_pid;
 	struct task_struct *child_reaper;
 	struct kmem_cache *pid_cachep;
+	int level;
+	struct pid_namespace *parent;
 };
 
 extern struct pid_namespace init_pid_ns;