diff --git a/include/uapi/linux/if_alg.h b/include/uapi/linux/if_alg.h
index b35871cbeed7..4f51e198ac2e 100644
--- a/include/uapi/linux/if_alg.h
+++ b/include/uapi/linux/if_alg.h
@@ -42,7 +42,7 @@ struct sockaddr_alg_new {
 
 struct af_alg_iv {
 	__u32	ivlen;
-	__u8	iv[];
+	__u8	iv[] __counted_by(ivlen);
 };
 
 /* Socket options */