From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754849AbaE1Xwv (ORCPT ); Wed, 28 May 2014 19:52:51 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:44515 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751625AbaE1Xwu (ORCPT ); Wed, 28 May 2014 19:52:50 -0400 Message-ID: <538676A7.6090306@oracle.com> Date: Wed, 28 May 2014 19:52:07 -0400 From: Sasha Levin User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: Peter Zijlstra CC: Ingo Molnar , acme@ghostprotocols.net, LKML , Thomas Gleixner , Dave Jones Subject: Re: perf: use after free in perf_remove_from_context References: <5370EBE9.6@oracle.com> <20140514162943.GR30445@twins.programming.kicks-ass.net> <53739A9A.5010703@oracle.com> <20140514163535.GS30445@twins.programming.kicks-ass.net> In-Reply-To: <20140514163535.GS30445@twins.programming.kicks-ass.net> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Source-IP: acsinet21.oracle.com [141.146.126.237] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/14/2014 12:35 PM, Peter Zijlstra wrote: > On Wed, May 14, 2014 at 12:32:26PM -0400, Sasha Levin wrote: >> > -----BEGIN PGP SIGNED MESSAGE----- >> > Hash: SHA1 >> > >> > On 05/14/2014 12:29 PM, Peter Zijlstra wrote: >>> > > On Mon, May 12, 2014 at 11:42:33AM -0400, Sasha Levin wrote: >>>> > >> Hi all, >>>> > >> >>>> > >> While fuzzing with trinity inside a KVM tools guest running the latest -next kernel I've stumbled on the following spew. Maybe related to the very recent change in freeing on task exit? >>>> > >> >>>> > >> [ 2509.827261] general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC [ 2509.830379] Dumping ftrace buffer: [ 2509.830379] (ftrace buffer empty) [ 2509.830379] Modules linked in: [ 2509.830379] CPU: 47 PID: 43306 Comm: trinity-c126 Tainted: G W 3.15.0-rc5-next-20140512-sasha-00019-ga20bc00-dirty #456 >>> > > >>> > > Any particular trinity setup? And would you happen to have the seed of that run? >> > >> > Nothing special about trinity options. 400 threads and blacklisting some of the >> > destructive syscalls (umount, reboot, etc). >> > >> > I don't have the seed, but that problem did reproduce again tonight so I can test >> > out debug code if you have something in mind. > Nah, I drew a pretty big blank, which is why I wanted to see if I could > reproduce. If you could share your trinity cmdline I'd be much obliged. > While I did manage to clone (the repo moved since last time) and build > it, I'm not really that handy with it and want to avoid destroying my > machine if possible ;-) Anything I could do to help out with this? It reproduces pretty easily on my configuration so I'd be happy to test out whatever might help. Thanks, Sasha