diff --git a/tools/testing/radix-tree/linux/lockdep.h b/tools/testing/radix-tree/linux/lockdep.h
index 016cff473cfc483963cd1b4586243fa3e73378e7..62473ab57f99c252237d9639a2155a30735a626f 100644
--- a/tools/testing/radix-tree/linux/lockdep.h
+++ b/tools/testing/radix-tree/linux/lockdep.h
@@ -11,4 +11,6 @@ static inline void lockdep_set_class(spinlock_t *lock,
 					struct lock_class_key *key)
 {
 }
+
+extern int lockdep_is_held(const void *);
 #endif /* _LINUX_LOCKDEP_H */