This is a note to let you know that I've just added the patch titled
ALSA: pcm: Remove yet superfluous WARN_ON()
to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: alsa-pcm-remove-yet-superfluous-warn_on.patch and it can be found in the queue-3.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From 23b19b7b50fe1867da8d431eea9cd3e4b6328c2c Mon Sep 17 00:00:00 2001
From: Takashi Iwai tiwai@suse.de Date: Wed, 10 Jan 2018 23:48:05 +0100 Subject: ALSA: pcm: Remove yet superfluous WARN_ON()
From: Takashi Iwai tiwai@suse.de
commit 23b19b7b50fe1867da8d431eea9cd3e4b6328c2c upstream.
muldiv32() contains a snd_BUG_ON() (which is morphed as WARN_ON() with debug option) for checking the case of 0 / 0. This would be helpful if this happens only as a logical error; however, since the hw refine is performed with any data set provided by user, the inconsistent values that can trigger such a condition might be passed easily. Actually, syzbot caught this by passing some zero'ed old hw_params ioctl.
So, having snd_BUG_ON() there is simply superfluous and rather harmful to give unnecessary confusions. Let's get rid of it.
Reported-by: syzbot+7e6ee55011deeebce15d@syzkaller.appspotmail.com Signed-off-by: Takashi Iwai tiwai@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- sound/core/pcm_lib.c | 1 - 1 file changed, 1 deletion(-)
--- a/sound/core/pcm_lib.c +++ b/sound/core/pcm_lib.c @@ -644,7 +644,6 @@ static inline unsigned int muldiv32(unsi { u_int64_t n = (u_int64_t) a * b; if (c == 0) { - snd_BUG_ON(!n); *r = 0; return UINT_MAX; }
Patches currently in stable-queue which might be from tiwai@suse.de are
queue-3.18/alsa-pcm-remove-yet-superfluous-warn_on.patch queue-3.18/alsa-hda-apply-the-existing-quirk-to-imac-14-1.patch