From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756764AbcBXLNT (ORCPT ); Wed, 24 Feb 2016 06:13:19 -0500 Received: from mx2.suse.de ([195.135.220.15]:42714 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754188AbcBXKF4 (ORCPT ); Wed, 24 Feb 2016 05:05:56 -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 3.12 031/142] ALSA: dummy: Disable switching timer backend via sysfs Date: Wed, 24 Feb 2016 11:03:46 +0100 Message-Id: <45d0f31cfeadeb31b3023c1919cda0d435d4bf31.1456308281.git.jslaby@suse.cz> X-Mailer: git-send-email 2.7.1 In-Reply-To: <173a4661a78d49aee0f4e28e4075f01af8976c19.1456308281.git.jslaby@suse.cz> References: <173a4661a78d49aee0f4e28e4075f01af8976c19.1456308281.git.jslaby@suse.cz> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Takashi Iwai 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 7ee96216c31aabe1eb42fb91ff50dae9fcd014b2 upstream. ALSA dummy driver can switch the timer backend between system timer and hrtimer via its hrtimer module option. This can be also switched dynamically via sysfs, but it may lead to a memory corruption when switching is done while a PCM stream is running; the stream instance for the newly switched timer method tries to access the memory that was allocated by another timer method although the sizes differ. As the simplest fix, this patch just disables the switch via sysfs by dropping the writable bit. BugLink: http://lkml.kernel.org/r/CACT4Y+ZGEeEBntHW5WHn2GoeE0G_kRrCmUh6=dWyy-wfzvuJLg@mail.gmail.com Reported-by: Dmitry Vyukov Signed-off-by: Takashi Iwai Signed-off-by: Jiri Slaby --- sound/drivers/dummy.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sound/drivers/dummy.c b/sound/drivers/dummy.c index 915b4d7fbb23..f4d626c05071 100644 --- a/sound/drivers/dummy.c +++ b/sound/drivers/dummy.c @@ -87,7 +87,7 @@ MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-128) for dummy driver."); module_param(fake_buffer, bool, 0444); MODULE_PARM_DESC(fake_buffer, "Fake buffer allocations."); #ifdef CONFIG_HIGH_RES_TIMERS -module_param(hrtimer, bool, 0644); +module_param(hrtimer, bool, 0444); MODULE_PARM_DESC(hrtimer, "Use hrtimer as the timer source."); #endif -- 2.7.1