From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S967876AbcA0Ui2 (ORCPT ); Wed, 27 Jan 2016 15:38:28 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:43085 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S967206AbcA0UiV (ORCPT ); Wed, 27 Jan 2016 15:38:21 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Takashi Iwai , Kamal Mostafa Subject: [PATCH 4.2.y-ckt 122/268] ALSA: timer: Fix double unlink of active_list Date: Wed, 27 Jan 2016 12:33:03 -0800 Message-Id: <1453926929-17663-123-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1453926929-17663-1-git-send-email-kamal@canonical.com> References: <1453926929-17663-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 4.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.2.8-ckt3 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Takashi Iwai 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 Tested-by: Dmitry Vyukov Signed-off-by: Takashi Iwai Signed-off-by: Kamal Mostafa --- sound/core/timer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sound/core/timer.c b/sound/core/timer.c index 31f40f0..9241784df 100644 --- a/sound/core/timer.c +++ b/sound/core/timer.c @@ -694,7 +694,7 @@ void snd_timer_interrupt(struct snd_timer * timer, unsigned long ticks_left) } 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)) -- 1.9.1