Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753315AbdCFJOE (ORCPT ); Mon, 6 Mar 2017 04:14:04 -0500 Received: from mx2.suse.de ([195.135.220.15]:37299 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753175AbdCFJNC (ORCPT ); Mon, 6 Mar 2017 04:13:02 -0500 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Takashi Iwai , Jiri Slaby Subject: [PATCH 3.12 045/113] ALSA: seq: Don't handle loop timeout at snd_seq_pool_done() Date: Mon, 6 Mar 2017 10:11:09 +0100 Message-Id: <7f262f3f9b4c1e65b6c079dd2441ea4297e1b7d0.1488791430.git.jslaby@suse.cz> X-Mailer: git-send-email 2.12.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1888 Lines: 56 From: Takashi Iwai 3.12-stable review patch. If anyone has any objections, please let me know. =============== 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: Jiri Slaby --- sound/core/seq/seq_memory.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) diff --git a/sound/core/seq/seq_memory.c b/sound/core/seq/seq_memory.c index 652350e2533f..7204c0f1700b 100644 --- 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_pool *pool) { 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_pool *pool) if (waitqueue_active(&pool->output_sleep)) wake_up(&pool->output_sleep); - while (atomic_read(&pool->counter) > 0) { - if (max_count == 0) { - snd_printk(KERN_WARNING "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); -- 2.12.0