Patch "ALSA: timer: Fix double unlink of active_list" has been added to the 4.4-stable tree

Patch "ALSA: timer: Fix double unlink of active_list" has been added to the 4.4-stable tree

[gregkh]

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

    ALSA: timer: Fix double unlink of active_list

to the 4.4-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-fix-double-unlink-of-active_list.patch
and it can be found in the queue-4.4 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 ee8413b01045c74340aa13ad5bdf905de32be736 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Wed, 13 Jan 2016 21:35:06 +0100
Subject: ALSA: timer: Fix double unlink of active_list

From: Takashi Iwai <tiwai@suse.de>

commit ee8413b01045c74340aa13ad5bdf905de32be736 upstream.

ALSA timer instance object has a couple of linked lists and they are
unlinked unconditionally at snd_timer_stop().  Meanwhile
snd_timer_interrupt() unlinks it, but it calls list_del() which leaves
the element list itself unchanged.  This ends up with unlinking twice,
and it was caught by syzkaller fuzzer.

The fix is to use list_del_init() variant properly there, too.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 sound/core/timer.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/sound/core/timer.c
+++ b/sound/core/timer.c
@@ -704,7 +704,7 @@ void snd_timer_interrupt(struct snd_time
 		} else {
 			ti->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
 			if (--timer->running)
-				list_del(&ti->active_list);
+				list_del_init(&ti->active_list);
 		}
 		if ((timer->hw.flags & SNDRV_TIMER_HW_TASKLET) ||
 		    (ti->flags & SNDRV_TIMER_IFLG_FAST))


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

queue-4.4/alsa-hrtimer-fix-stall-by-hrtimer_cancel.patch
queue-4.4/alsa-hda-fix-white-noise-on-dell-latitude-e5550.patch
queue-4.4/alsa-hda-fix-the-headset-mic-detection-problem-for-a-dell-laptop.patch
queue-4.4/alsa-timer-harden-slave-timer-list-handling.patch
queue-4.4/alsa-timer-fix-double-unlink-of-active_list.patch
queue-4.4/alsa-control-avoid-kernel-warnings-from-tlv-ioctl-with-numid-0.patch
queue-4.4/alsa-hda-flush-the-pending-probe-work-at-remove.patch
queue-4.4/alsa-hda-fixup-inverted-internal-mic-for-lenovo-e50-80.patch
queue-4.4/alsa-usb-add-native-dsd-support-for-oppo-ha-1.patch
queue-4.4/alsa-hda-fix-missing-module-loading-with-model-generic-option.patch
queue-4.4/alsa-seq-fix-race-at-timer-setup-and-close.patch
queue-4.4/alsa-pcm-fix-snd_pcm_hw_params-struct-copy-in-compat-mode.patch
queue-4.4/alsa-seq-fix-snd_seq_call_port_info_ioctl-in-compat-mode.patch
queue-4.4/alsa-seq-fix-missing-null-check-at-remove_events-ioctl.patch
queue-4.4/alsa-usb-audio-fix-mixer-ctl-regression-of-native-instrument-devices.patch
queue-4.4/alsa-timer-handle-disconnection-more-safely.patch
queue-4.4/alsa-hda-fix-bass-pin-fixup-for-asus-n550jx.patch
queue-4.4/alsa-timer-fix-race-among-timer-ioctls.patch
queue-4.4/alsa-hda-add-fixup-for-dell-latitidue-e6540.patch
queue-4.4/alsa-usb-audio-avoid-calling-usb_autopm_put_interface-at-disconnect.patch