diff --git a/net/ceph/crypto.c b/net/ceph/crypto.c
index 292e33bd916e..5f3a627afcc6 100644
--- a/net/ceph/crypto.c
+++ b/net/ceph/crypto.c
@@ -34,7 +34,9 @@ static int set_secret(struct ceph_crypto_key *key, void *buf)
 		return -ENOTSUPP;
 	}
 
-	WARN_ON(!key->len);
+	if (!key->len)
+		return -EINVAL;
+
 	key->key = kmemdup(buf, key->len, GFP_NOIO);
 	if (!key->key) {
 		ret = -ENOMEM;