From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751181AbWDEJBX (ORCPT ); Wed, 5 Apr 2006 05:01:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751182AbWDEJBX (ORCPT ); Wed, 5 Apr 2006 05:01:23 -0400 Received: from mail.gondor.com ([212.117.64.182]:42756 "EHLO moria.gondor.com") by vger.kernel.org with ESMTP id S1751181AbWDEJBX (ORCPT ); Wed, 5 Apr 2006 05:01:23 -0400 Date: Wed, 5 Apr 2006 11:01:17 +0200 From: Jan Niehusmann To: Takashi Iwai Cc: Ken Moffat , linux-kernel@vger.kernel.org, alsa-devel@alsa-project.org Subject: Re: [Alsa-devel] Slab corruptions & Re: 2.6.17-rc1: Oops in sound applications Message-ID: <20060405090117.GB4794@knautsch.gondor.com> References: <20060404133814.GA11741@knautsch.gondor.com> <20060404190631.GA4895@knautsch.gondor.com> <20060404231911.GA4862@knautsch.gondor.com> <20060405002846.GA5201@knautsch.gondor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060405002846.GA5201@knautsch.gondor.com> User-Agent: Mutt/1.5.11+cvs20060126 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 05, 2006 at 02:28:47AM +0200, Jan Niehusmann wrote: > If I now add the patch you suggested, correcting the check in > snd_pcm_oss_open_file(), accessing /dev/dsp instead leads to EINVAL. > > So I guess git bisect really lead me to this already known bug. And another update. Sorry for sending so many small mails, but I want to keep you informed to avoid unnecessary duplication of work. To make sure I didn't do something stupid like confusing kernel versions, I retried with 2.6.17-rc1 and the mentioned patch. It oopses again, but the behaviour is different: Versions 2.6.16 to commit bf1bbb5a49eec51c30d341606885507b501b37e8 only allow a single open of /dev/dsp, and do not oops. Commit 3bf75f9b90c981f18f27a0d35a44f488ab68c8ea and later do oops with commands as simple as 'yes >/dev/dsp'. Commit 3bf75f9b90c981f18f27a0d35a44f488ab68c8ea with the patch to snd_pcm_oss_open_file() applied do not oops, but block every access to /dev/dsp with EINVAL. 2.6.17-rc1 with the patch to snd_pcm_oss_open_file(), again, allows opening of /dev/dsp, 'yes >/dev/dsp' does work as expected, but for example twinkle (a VoIP application) gives garbled sound. Additionally, I am now able to open /dev/dsp a second time (eg. 'yes >/dev/dsp' while twinkle uses the sound device), immediately leading to an oops. My guess is that this bug is just not triggered in commit 3bf75f9b90c981f18f27a0d35a44f488ab68c8ea because, for some other reason, /dev/dsp is completely unusable. Jan