diff --git a/crypto/chacha20poly1305.c b/crypto/chacha20poly1305.c
index 9e4651330852..d740849f1c19 100644
--- a/crypto/chacha20poly1305.c
+++ b/crypto/chacha20poly1305.c
@@ -27,7 +27,7 @@ struct chachapoly_ctx {
 	struct crypto_ahash *poly;
 	/* key bytes we use for the ChaCha20 IV */
 	unsigned int saltlen;
-	u8 salt[];
+	u8 salt[] __counted_by(saltlen);
 };
 
 struct poly_req {