ALSA: seq: Fix incorrect sanity check at snd_seq_oss_synth_cleanup()

commit 599151336638d57b98d92338aa59c048e3a3e97d upstream.

ALSA sequencer OSS emulation code has a sanity check for currently
opened devices, but there is a thinko there, eventually it spews
warnings and skips the operation wrongly like:
  WARNING: CPU: 1 PID: 7573 at sound/core/seq/oss/seq_oss_synth.c:311

Fix this off-by-one error.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/sound/core/seq/oss/seq_oss_synth.c b/sound/core/seq/oss/seq_oss_synth.c
index c5b773a..4a09c30 100644 (file)
--- a/sound/core/seq/oss/seq_oss_synth.c
+++ b/sound/core/seq/oss/seq_oss_synth.c
@@ -310,7 +310,7 @@ snd_seq_oss_synth_cleanup(struct seq_oss_devinfo *dp)
        struct seq_oss_synth *rec;
        struct seq_oss_synthinfo *info;
 
-       if (snd_BUG_ON(dp->max_synthdev >= SNDRV_SEQ_OSS_MAX_SYNTH_DEVS))
+       if (snd_BUG_ON(dp->max_synthdev > SNDRV_SEQ_OSS_MAX_SYNTH_DEVS))
                return;
        for (i = 0; i < dp->max_synthdev; i++) {
                info = &dp->synths[i];