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 S1752393Ab3JOGkb (ORCPT <rfc822;w@1wt.eu>);
	Tue, 15 Oct 2013 02:40:31 -0400
Received: from mail-ee0-f48.google.com ([74.125.83.48]:51488 "EHLO
	mail-ee0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1750769Ab3JOGk3 (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Tue, 15 Oct 2013 02:40:29 -0400
Date: Tue, 15 Oct 2013 08:40:25 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Knut Petersen <Knut_Petersen@t-online.de>,
        Thomas Gleixner <tglx@linutronix.de>, Greg KH <greg@kroah.com>,
        linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [BUG 3.12.rc4] Oops: unable to handle kernel paging request
 during shutdown
Message-ID: <20131015064025.GA22672@gmail.com>
References: <525BD08C.2080101@t-online.de>
 <CA+55aFwN++wO=rTFaH7m6YYQX+Fv3qDt6Hxs7UnPUJpFsrwSkA@mail.gmail.com>
 <20131014212830.GD5790@linux.vnet.ibm.com>
 <20131014215117.GE13538@localhost.localdomain>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20131014215117.GE13538@localhost.localdomain>
User-Agent: Mutt/1.5.21 (2010-09-15)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org


* Frederic Weisbecker <fweisbec@gmail.com> wrote:

> I've been thinking that CONFIG_DEBUG_LIST could help. Unfortunately it's 
> good to spot list APIs misuse but, if Linus is right, the problem may be 
> that the list belongs to an object that has been freed, and I believe 
> that won't detect such a thing.

Use-after free should be reliably detectable via CONFIG_DEBUG_PAGEALLOC=y.

A couple of years ago I wrote a list debugging beast that would catch 
use-after-free mishaps (sent it to lkml too IIRC), but it was a bit 
complex and I never found the time to nurse it upstream.

Thanks,

	Ingo