diff --git a/include/linux/pid.h b/include/linux/pid.h
index 33d3438..1e0e4e3 100644
--- a/include/linux/pid.h
+++ b/include/linux/pid.h
@@ -51,6 +51,8 @@
 	struct rcu_head rcu;
 };
 
+extern struct pid init_struct_pid;
+
 struct pid_link
 {
 	struct hlist_node node;