From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:48008 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752430AbdCHK1z (ORCPT ); Wed, 8 Mar 2017 05:27:55 -0500 Subject: Patch "ALSA: seq: Fix link corruption by event error handling" has been added to the 4.4-stable tree To: tiwai@suse.de, dvyukov@google.com, gregkh@linuxfoundation.org Cc: , From: Date: Wed, 08 Mar 2017 11:27:15 +0100 Message-ID: <148896883543241@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled ALSA: seq: Fix link corruption by event error handling 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-seq-fix-link-corruption-by-event-error-handling.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 know about it. >>From f3ac9f737603da80c2da3e84b89e74429836bb6d Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Tue, 28 Feb 2017 22:15:51 +0100 Subject: ALSA: seq: Fix link corruption by event error handling From: Takashi Iwai commit f3ac9f737603da80c2da3e84b89e74429836bb6d upstream. The sequencer FIFO management has a bug that may lead to a corruption (shortage) of the cell linked list. When a sequencer client faces an error at the event delivery, it tries to put back the dequeued cell. When the first queue was put back, this forgot the tail pointer tracking, and the link will be screwed up. Although there is no memory corruption, the sequencer client may stall forever at exit while flushing the pending FIFO cells in snd_seq_pool_done(), as spotted by syzkaller. This patch addresses the missing tail pointer tracking at snd_seq_fifo_cell_putback(). Also the patch makes sure to clear the cell->enxt pointer at snd_seq_fifo_event_in() for avoiding a similar mess-up of the FIFO linked list. Reported-by: Dmitry Vyukov Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/core/seq/seq_fifo.c | 3 +++ 1 file changed, 3 insertions(+) --- a/sound/core/seq/seq_fifo.c +++ b/sound/core/seq/seq_fifo.c @@ -135,6 +135,7 @@ int snd_seq_fifo_event_in(struct snd_seq f->tail = cell; if (f->head == NULL) f->head = cell; + cell->next = NULL; f->cells++; spin_unlock_irqrestore(&f->lock, flags); @@ -214,6 +215,8 @@ void snd_seq_fifo_cell_putback(struct sn spin_lock_irqsave(&f->lock, flags); cell->next = f->head; f->head = cell; + if (!f->tail) + f->tail = cell; f->cells++; spin_unlock_irqrestore(&f->lock, flags); } Patches currently in stable-queue which might be from tiwai@suse.de are queue-4.4/alsa-hda-add-subwoofer-support-for-dell-inspiron-17-7000-gaming.patch queue-4.4/alsa-seq-fix-link-corruption-by-event-error-handling.patch queue-4.4/alsa-hda-fix-micmute-hotkey-problem-for-a-lenovo-aio-machine.patch queue-4.4/alsa-ctxfi-fallback-dma-mask-to-32bit.patch queue-4.4/alsa-timer-reject-user-params-with-too-small-ticks.patch queue-4.4/alsa-hda-fix-lewisburg-audio-issue.patch queue-4.4/alsa-hda-realtek-cannot-adjust-speaker-s-volume-on-a-dell-aio.patch