Patch "ALSA: timer: Remove kernel warning at compat ioctl error paths" has been added to the 3.18-stable tree

Patch "ALSA: timer: Remove kernel warning at compat ioctl error paths" has been added to the 3.18-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    ALSA: timer: Remove kernel warning at compat ioctl error paths

to the 3.18-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     alsa-timer-remove-kernel-warning-at-compat-ioctl-error-paths.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 3d4e8303f2c747c8540a0a0126d0151514f6468b Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Tue, 21 Nov 2017 16:36:11 +0100
Subject: ALSA: timer: Remove kernel warning at compat ioctl error paths

From: Takashi Iwai <tiwai@suse.de>

commit 3d4e8303f2c747c8540a0a0126d0151514f6468b upstream.

Some timer compat ioctls have NULL checks of timer instance with
snd_BUG_ON() that bring up WARN_ON() when the debug option is set.
Actually the condition can be met in the normal situation and it's
confusing and bad to spew kernel warnings with stack trace there.
Let's remove snd_BUG_ON() invocation and replace with the simple
checks.  Also, correct the error code to EBADFD to follow the native
ioctl error handling.

Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 sound/core/timer_compat.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

--- a/sound/core/timer_compat.c
+++ b/sound/core/timer_compat.c
@@ -40,11 +40,11 @@ static int snd_timer_user_info_compat(st
 	struct snd_timer *t;
 
 	tu = file->private_data;
-	if (snd_BUG_ON(!tu->timeri))
-		return -ENXIO;
+	if (!tu->timeri)
+		return -EBADFD;
 	t = tu->timeri->timer;
-	if (snd_BUG_ON(!t))
-		return -ENXIO;
+	if (!t)
+		return -EBADFD;
 	memset(&info, 0, sizeof(info));
 	info.card = t->card ? t->card->number : -1;
 	if (t->hw.flags & SNDRV_TIMER_HW_SLAVE)
@@ -73,8 +73,8 @@ static int snd_timer_user_status_compat(
 	struct snd_timer_status32 status;
 	
 	tu = file->private_data;
-	if (snd_BUG_ON(!tu->timeri))
-		return -ENXIO;
+	if (!tu->timeri)
+		return -EBADFD;
 	memset(&status, 0, sizeof(status));
 	status.tstamp.tv_sec = tu->tstamp.tv_sec;
 	status.tstamp.tv_nsec = tu->tstamp.tv_nsec;


Patches currently in stable-queue which might be from tiwai@suse.de are

queue-3.18/alsa-usb-audio-fix-potential-zero-division-at-parsing-fu.patch
queue-3.18/alsa-timer-remove-kernel-warning-at-compat-ioctl-error-paths.patch
queue-3.18/alsa-hda-add-raven-pci-id.patch
queue-3.18/alsa-usb-audio-add-sanity-checks-in-v2-clock-parsers.patch
queue-3.18/alsa-usb-audio-fix-potential-out-of-bound-access-at-parsing-su.patch
queue-3.18/alsa-usb-audio-add-sanity-checks-to-fe-parser.patch