diff --git a/sound/usb/stream.c b/sound/usb/stream.c
index c4f4585f9b85..f51e901a9689 100644
--- a/sound/usb/stream.c
+++ b/sound/usb/stream.c
@@ -301,9 +301,12 @@ static struct snd_pcm_chmap_elem *convert_chmap(int channels, unsigned int bits,
 	c = 0;
 
 	if (bits) {
-		for (; bits && *maps; maps++, bits >>= 1)
+		for (; bits && *maps; maps++, bits >>= 1) {
 			if (bits & 1)
 				chmap->map[c++] = *maps;
+			if (c == chmap->channels)
+				break;
+		}
 	} else {
 		/* If we're missing wChannelConfig, then guess something
 		    to make sure the channel map is not skipped entirely */