diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index a8f981a2d1109309c5e06fb79fcd5a047f11ed86..79c3877e9c5b83e089ef319a2e72a9aaddde6fa3 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -96,7 +96,7 @@ static inline void debug_rcu_head_unqueue(struct rcu_head *head)
 }
 #endif	/* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
 
-extern void kfree(const void *);
+void kfree(const void *);
 
 static inline bool __rcu_reclaim(const char *rn, struct rcu_head *head)
 {