diff --git a/fs/btrfs/rcu-string.h b/fs/btrfs/rcu-string.h
index a97dc74a4d3d..5c1a617eb25d 100644
--- a/fs/btrfs/rcu-string.h
+++ b/fs/btrfs/rcu-string.h
@@ -8,7 +8,7 @@
 
 struct rcu_string {
 	struct rcu_head rcu;
-	char str[0];
+	char str[];
 };
 
 static inline struct rcu_string *rcu_string_strdup(const char *src, gfp_t mask)