diff --git a/include/keys/user-type.h b/include/keys/user-type.h
index e098cbe27db5..12babe991594 100644
--- a/include/keys/user-type.h
+++ b/include/keys/user-type.h
@@ -31,7 +31,7 @@
 struct user_key_payload {
 	struct rcu_head	rcu;		/* RCU destructor */
 	unsigned short	datalen;	/* length of this data */
-	char		data[0];	/* actual data */
+	char		data[0] __aligned(__alignof__(u64)); /* actual data */
 };
 
 extern struct key_type key_type_user;