Commit 400d3eff authored Jun 02, 2021 by Takashi Iwai Committed by Greg Kroah-Hartman Jun 10, 2021

ALSA: timer: Fix master timer notification



commit 9c1fe96bded935369f8340c2ac2e9e189f697d5d upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent cc302e30

sound/core/timer.c

+2 −1

Original line number	Original line	Diff line number	Diff line
	@@ -432,9 +432,10 @@ static void snd_timer_notify1(struct snd_timer_instance *ti, int event)
	return;		return;
	if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)		if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
	return;		return;
			event += 10; /* convert to SNDRV_TIMER_EVENT_MXXX */
	list_for_each_entry(ts, &ti->slave_active_head, active_list)		list_for_each_entry(ts, &ti->slave_active_head, active_list)
	if (ts->ccallback)		if (ts->ccallback)
	ts->ccallback(ts, event + 100, &tstamp, resolution);		ts->ccallback(ts, event, &tstamp, resolution);
	}		}

	/* start/continue a master timer */		/* start/continue a master timer */