From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752112Ab0DJWAE (ORCPT ); Sat, 10 Apr 2010 18:00:04 -0400 Received: from mail.skyhub.de ([78.46.96.112]:60035 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751176Ab0DJWAA (ORCPT ); Sat, 10 Apr 2010 18:00:00 -0400 Date: Sat, 10 Apr 2010 23:51:15 +0200 From: Borislav Petkov To: Linus Torvalds Cc: Johannes Weiner , KOSAKI Motohiro , Rik van Riel , Andrew Morton , Minchan Kim , Linux Kernel Mailing List , Lee Schermerhorn , Nick Piggin , Andrea Arcangeli , Hugh Dickins , sgunderson@bigfoot.com Subject: Re: [PATCH -v2] rmap: make anon_vma_prepare link in all the anon_vmas of a mergeable VMA Message-ID: <20100410215115.GA2599@a1.tnic> Mail-Followup-To: Borislav Petkov , Linus Torvalds , Johannes Weiner , KOSAKI Motohiro , Rik van Riel , Andrew Morton , Minchan Kim , Linux Kernel Mailing List , Lee Schermerhorn , Nick Piggin , Andrea Arcangeli , Hugh Dickins , sgunderson@bigfoot.com References:

<20100410185145.GB28952@a1.tnic> <20100410185839.GA32035@a1.tnic>

<20100410203628.GB32035@a1.tnic> <20100410212555.GA1797@a1.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Linus Torvalds Date: Sat, Apr 10, 2010 at 02:30:49PM -0700 > On Sat, 10 Apr 2010, Borislav Petkov wrote: > > > > Damn, nope, still no joy :(. It looked like it was fixed but one of the > > test was to hibernate right after the 3 kvm guests were shut down and I > > guess the mem freeing pattern kinda hits it where it most hurts. > > Damn, I really hoped that was it. Three independent bugs found and fixed, > and still no joy? Oh well. Yep, I'll redo the testing tomorrow, so that we are sure that even with the _three_ bugs fixed we still hit the funky list element issue. > > By the way, do we want to create a new thread - the mailchain is off the > > screen limits of my netbook :) > > I prefer to keep it in one thread so that they all show up together if I > need to, but feel free to start a new one. Not a biggie. I'll keep the thread then - I didn't know it mattered. Mine was just a suggestion, nevermind. > > [ 647.492781] BUG: unable to handle kernel NULL pointer dereference at (null) > > [ 647.493001] IP: [] page_referenced+0xee/0x1dc > > Well, it sure is consistent. I'll start to think about what else could go > wrong.. Which could mean that even with those issues fixed, the real issue is yet something else. Because obviously the fixes you throw at it don't seem to change it - even the traces remain consistent across tests. And if it is use-after-free case, the funny patterns could be some shifted SLUB poison values which we happen to "see" through the dangling pointer... I dunno. Hmm. -- Regards/Gruss, Boris.