diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index 1050008d7719..90ea49a53dc0 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -203,6 +203,10 @@ static int snd_usb_copy_string_desc(struct mixer_build *state,
 				    int index, char *buf, int maxlen)
 {
 	int len = usb_string(state->chip->dev, index, buf, maxlen - 1);
+
+	if (len < 0)
+		return 0;
+
 	buf[len] = 0;
 	return len;
 }