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 @@ struct pid_namespace {
 	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;
diff --git a/kernel/pid.c b/kernel/pid.c
index bb07851..c7346fb 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -67,7 +67,8 @@ struct pid_namespace init_pid_ns = {
 		[ 0 ... PIDMAP_ENTRIES-1] = { ATOMIC_INIT(BITS_PER_PAGE), NULL }
 	},
 	.last_pid = 0,
-	.child_reaper = &init_task
+	.level = 0,
+	.child_reaper = &init_task,
 };
 
 int is_global_init(struct task_struct *tsk)