From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755985AbaENQfn (ORCPT ); Wed, 14 May 2014 12:35:43 -0400 Received: from casper.infradead.org ([85.118.1.10]:50722 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751620AbaENQfm (ORCPT ); Wed, 14 May 2014 12:35:42 -0400 Date: Wed, 14 May 2014 18:35:35 +0200 From: Peter Zijlstra To: Sasha Levin Cc: Ingo Molnar , acme@ghostprotocols.net, LKML , Thomas Gleixner , Dave Jones Subject: Re: perf: use after free in perf_remove_from_context Message-ID: <20140514163535.GS30445@twins.programming.kicks-ass.net> References: <5370EBE9.6@oracle.com> <20140514162943.GR30445@twins.programming.kicks-ass.net> <53739A9A.5010703@oracle.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="CmWxRWyFvh6D3sQF" Content-Disposition: inline In-Reply-To: <53739A9A.5010703@oracle.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --CmWxRWyFvh6D3sQF Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, May 14, 2014 at 12:32:26PM -0400, Sasha Levin wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 >=20 > 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, > >>=20 > >> 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 ver= y recent change in freeing on task exit? > >>=20 > >> [ 2509.827261] general protection fault: 0000 [#1] PREEMPT SMP DEBUG_P= AGEALLOC [ 2509.830379] Dumping ftrace buffer: [ 2509.830379] (ftrace bu= ffer empty) [ 2509.830379] Modules linked in: [ 2509.830379] CPU: 47 PID: 4= 3306 Comm: trinity-c126 Tainted: G W 3.15.0-rc5-next-20140512-sa= sha-00019-ga20bc00-dirty #456 > >=20 > > Any particular trinity setup? And would you happen to have the seed of = that run? >=20 > Nothing special about trinity options. 400 threads and blacklisting some = of the > destructive syscalls (umount, reboot, etc). >=20 > 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 ;-) --CmWxRWyFvh6D3sQF Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJTc5tXAAoJEHZH4aRLwOS68PkP/0hZZVAdBAkJwXZPsFM4aUY4 dRlOYmATpK3UaZFZePwvuHpoAHNjC3JWLq1TjZcz+cpmZCq7bfh7gFDnslXZniRw d89f8CxwmN9+ZhS2hHJmtE8hzGAY3ZEv8/ZlZGxj3yaEIeNXfKSAb/bI9kG0ISCn GDpuopvgcM3kh8ZkzPYv+PJBDQDbhoohj2/DjFy0hsB8+j78nY+oCrjNdI4bzM2G TuATYDetssarCUAosHoQv7gIP4cXAgYyjY+CGov9F20etNltSO59v9rhKYhFjpq2 MaAykJlBTAcjZp8dsVjLekqcD5rFGdyhCeORD1s3etdTKKv0qf2b1BHwdj/raPQe CM92oDWVb5U3Rk5Su7d0r2iD1RwhFb482ccMgxSRYvqaU/5xFzdIOFtskZTCLTPi 1CjLk8mTwCY9ggl+eri/4anvHQCUBJIUucdlrkWeKze2PoxIvyzF/vktdIjPSrR8 RB6u439aErTxzVS24eWsqsOpeLKizskPQ3RX7wiNoqp6wV33qr85/SIer5qz7Fsv aBCXbIqmEFHsWK/lyONAWcS/QpeX9St1lQCbU71YcfhVbqlc/+HDienp1W8YMicG CXzIyK48yauk1rVJcIobF8zB8hcCpCVLkaKURCCbPbEbJr1QrIy82mse82C3vfqa tvjioAVnoe5hlvSxX/m8 =gOAR -----END PGP SIGNATURE----- --CmWxRWyFvh6D3sQF--