diff --git a/sys/dev/sound/midi/sequencer.c b/sys/dev/sound/midi/sequencer.c
--- a/sys/dev/sound/midi/sequencer.c
+++ b/sys/dev/sound/midi/sequencer.c
@@ -750,6 +750,7 @@
 	mtx_lock(&scp->seq_lock);
 	if (scp->busy) {
 		mtx_unlock(&scp->seq_lock);
+		midistat_unlock();
 		SEQ_DEBUG(2, printf("seq_open: unit %d is busy.\n", scp->unit));
 		return EBUSY;
 	}