diff --git a/sys/dev/sound/dummy.c b/sys/dev/sound/dummy.c
--- a/sys/dev/sound/dummy.c
+++ b/sys/dev/sound/dummy.c
@@ -76,7 +76,7 @@
 
 	for (i = 0; i < sc->chnum; i++) {
 		ch = &sc->chans[i];
-		if (!ch->run)
+		if (!ch->run || ch->chan == NULL || ch->buf == NULL)
 			continue;
 		if (ch->dir == PCMDIR_PLAY)
 			ch->ptr += sndbuf_getblksz(ch->buf);