From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:48044 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751507AbdBLWPN (ORCPT ); Sun, 12 Feb 2017 17:15:13 -0500 Subject: Patch "ALSA: seq: Don't handle loop timeout at snd_seq_pool_done()" has been added to the 4.4-stable tree To: tiwai@suse.de, dvyukov@google.com, gregkh@linuxfoundation.org Cc: , From: Date: Sun, 12 Feb 2017 14:15:12 -0800 Message-ID: <14869377123310@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: Don't handle loop timeout at snd_seq_pool_done() 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-don-t-handle-loop-timeout-at-snd_seq_pool_done.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 37a7ea4a9b81f6a864c10a7cb0b96458df5310a3 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Mon, 6 Feb 2017 15:09:48 +0100 Subject: ALSA: seq: Don't handle loop timeout at snd_seq_pool_done() From: Takashi Iwai commit 37a7ea4a9b81f6a864c10a7cb0b96458df5310a3 upstream. snd_seq_pool_done() syncs with closing of all opened threads, but it aborts the wait loop with a timeout, and proceeds to the release resource even if not all threads have been closed. The timeout was 5 seconds, and if you run a crazy stuff, it can exceed easily, and may result in the access of the invalid memory address -- this is what syzkaller detected in a bug report. As a fix, let the code graduate from naiveness, simply remove the loop timeout. BugLink: http://lkml.kernel.org/r/CACT4Y+YdhDV2H5LLzDTJDVF-qiYHUHhtRaW4rbb4gUhTCQB81w@mail.gmail.com Reported-by: Dmitry Vyukov Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/core/seq/seq_memory.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) --- a/sound/core/seq/seq_memory.c +++ b/sound/core/seq/seq_memory.c @@ -419,7 +419,6 @@ int snd_seq_pool_done(struct snd_seq_poo { unsigned long flags; struct snd_seq_event_cell *ptr; - int max_count = 5 * HZ; if (snd_BUG_ON(!pool)) return -EINVAL; @@ -432,14 +431,8 @@ int snd_seq_pool_done(struct snd_seq_poo if (waitqueue_active(&pool->output_sleep)) wake_up(&pool->output_sleep); - while (atomic_read(&pool->counter) > 0) { - if (max_count == 0) { - pr_warn("ALSA: snd_seq_pool_done timeout: %d cells remain\n", atomic_read(&pool->counter)); - break; - } + while (atomic_read(&pool->counter) > 0) schedule_timeout_uninterruptible(1); - max_count--; - } /* release all resources */ spin_lock_irqsave(&pool->lock, flags); Patches currently in stable-queue which might be from tiwai@suse.de are queue-4.4/alsa-seq-don-t-handle-loop-timeout-at-snd_seq_pool_done.patch queue-4.4/alsa-seq-fix-race-at-creating-a-queue.patch