From 9c1fe96bded935369f8340c2ac2e9e189f697d5d Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Wed, 2 Jun 2021 13:38:23 +0200
Subject: [PATCH] ALSA: timer: Fix master timer notification
Git-commit: 9c1fe96bded935369f8340c2ac2e9e189f697d5d
Patch-mainline: v5.13-rc5
References: git-fixes
snd_timer_notify1() calls the notification to each slave for a master
event, but it passes a wrong event number. It should be +10 offset,
corresponding to SNDRV_TIMER_EVENT_MXXX, but it's incorrectly with
+100 offset. Casually this was spotted by UBSAN check via syzkaller.
Reported-by: syzbot+d102fa5b35335a7e544e@syzkaller.appspotmail.com
Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/000000000000e5560e05c3bd1d63@google.com
Link: https://lore.kernel.org/r/20210602113823.23777-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
sound/core/timer.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/sound/core/timer.c b/sound/core/timer.c
index 6898b1ac0d7f..92b7008fcdb8 100644
--- a/sound/core/timer.c
+++ b/sound/core/timer.c
@@ -520,9 +520,10 @@ static void snd_timer_notify1(struct snd_timer_instance *ti, int event)
return;
if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
return;
+ event += 10; /* convert to SNDRV_TIMER_EVENT_MXXX */
list_for_each_entry(ts, &ti->slave_active_head, active_list)
if (ts->ccallback)
- ts->ccallback(ts, event + 100, &tstamp, resolution);
+ ts->ccallback(ts, event, &tstamp, resolution);
}
/* start/continue a master timer */
--
2.26.2