From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1755269AbdKBI6L (ORCPT <rfc822;w@1wt.eu>);
        Thu, 2 Nov 2017 04:58:11 -0400
Received: from mx2.suse.de ([195.135.220.15]:37328 "EHLO mx2.suse.de"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1750883AbdKBI6G (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Thu, 2 Nov 2017 04:58:06 -0400
Date: Thu, 02 Nov 2017 09:58:04 +0100
Message-ID: <s5h60at83c3.wl-tiwai@suse.de>
From: Takashi Iwai <tiwai@suse.de>
To: "Dmitry Vyukov" <dvyukov@google.com>
Cc: "syzbot" 
        <bot+31681772ec7a18dde8d3f8caf475f361a89b9514@syzkaller.appspotmail.com>,
        <alsa-devel@alsa-project.org>, <syzkaller-bugs@googlegroups.com>,
        "Jaroslav Kysela" <perex@perex.cz>,
        "LKML" <linux-kernel@vger.kernel.org>,
        "Mark Salyzyn" <salyzyn@android.com>
Subject: Re: BUG: unable to handle kernel paging request in snd_seq_oss_readq_puts
In-Reply-To: <s5h4lqddbk9.wl-tiwai@suse.de>
References: <001a1140b6b825822a055cf02f93@google.com>
        <CACT4Y+a2eNABZqqcGe1idMX80pS+HrYgM74BiNz8LZjNXDPKXA@mail.gmail.com>
        <s5h4lqddbk9.wl-tiwai@suse.de>
User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka)
 FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.3
 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO)
MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka")
Content-Type: text/plain; charset=US-ASCII
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Wed, 01 Nov 2017 20:49:10 +0100,
Takashi Iwai wrote:
> 
> On Wed, 01 Nov 2017 19:39:46 +0100,
> Dmitry Vyukov wrote:
> > 
> > On Wed, Nov 1, 2017 at 9:38 PM, syzbot
> > <bot+31681772ec7a18dde8d3f8caf475f361a89b9514@syzkaller.appspotmail.com>
> > wrote:
> > > Hello,
> > >
> > > syzkaller hit the following crash on
> > > fc2e8b1a47c14b22c33eb087fca0db58e1f4ed0e
> > > git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master
> > > compiler: gcc (GCC) 7.1.1 20170620
> > > .config is attached
> > > Raw console output is attached.
> > > C reproducer is attached
> > > syzkaller reproducer is attached. See https://goo.gl/kgGztJ
> > > for information about syzkaller reproducers
> > 
> > This also happened on more recent commits, including upstream
> > 9c323bff13f92832e03657cabdd70d731408d621 (Oct 20):
> 
> Could you try the patch below with CONFIG_SND_DEBUG=y and see whether
> it catches any bad calls?  It's already in for-next branch for 4.15.

And now I remember that it's the exactly same bug Mark Salyzyn
reported sometime ago, msgid
 <20171006171731.88889-1-salyzyn@android.com>

So this is likely hitting an invalid page, if Mark's analysis is
correct.


thanks,

Takashi