ALSA: opl3: Fix possible negative array index access

Spotted by coverity CID 115196.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 5 insertions, 0 deletions

diff --git a/sound/drivers/opl3/opl3_midi.c b/sound/drivers/opl3/opl3_midi.c
index 0c796bcbc0a3..6c6d09a51f42 100644
--- a/sound/drivers/opl3/opl3_midi.c
+++ b/sound/drivers/opl3/opl3_midi.c
@@ -390,6 +390,11 @@ void snd_opl3_note_on(void *p, int note, int vel, struct snd_midi_channel *chan)
                 voice = snd_opl3_oss_map[chan->number];         
         }
 
+        if (voice < 0) {
+                spin_unlock_irqrestore(&opl3->voice_lock, flags);
+                return;
+        }
+
         if (voice < MAX_OPL2_VOICES) {
                 /* Left register block for voices 0 .. 8 */
                 reg_side = OPL3_LEFT;