diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index a87adfc2..8c19873 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -571,6 +571,7 @@
 				  unsigned long maxj);
 static void rcu_bind_gp_kthread(void);
 static void rcu_sysidle_init_percpu_data(struct rcu_dynticks *rdtp);
+static bool rcu_nohz_full_cpu(struct rcu_state *rsp);
 
 #endif /* #ifndef RCU_TREE_NONCORE */