From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030238AbaEQRA5 (ORCPT ); Sat, 17 May 2014 13:00:57 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:51607 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964813AbaEQRA4 (ORCPT ); Sat, 17 May 2014 13:00:56 -0400 Date: Sat, 17 May 2014 19:00:37 +0200 From: Peter Zijlstra To: Sasha Levin Cc: "Theodore Ts'o" , Hannes Frederic Sowa , "H. Peter Anvin" , Ingo Molnar , acme@ghostprotocols.net, LKML , Thomas Gleixner , Dave Jones , price@mit.edu Subject: Re: BUG_ON drivers/char/random.c:986 (Was: perf: use after free in perf_remove_from_context) Message-ID: <20140517170037.GA11096@twins.programming.kicks-ass.net> References: <5370EBE9.6@oracle.com> <20140516153455.GV11096@twins.programming.kicks-ass.net> <53763775.3040602@linux.intel.com> <20140516162117.GY11096@twins.programming.kicks-ass.net> <1400287582.11005.118359877.7B81534B@webmail.messagingengine.com> <20140517021840.GA5513@thunk.org> <53778D40.5020203@oracle.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="U4Pv8ouM+6WX/UB7" Content-Disposition: inline In-Reply-To: <53778D40.5020203@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 --U4Pv8ouM+6WX/UB7 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sat, May 17, 2014 at 12:24:32PM -0400, Sasha Levin wrote: > On 05/16/2014 10:18 PM, Theodore Ts'o wrote: > > On Fri, May 16, 2014 at 05:46:22PM -0700, Hannes Frederic Sowa wrote: > >> > This should do the trick: > >> > dd if=3D/dev/urandom of=3D/dev/zero bs=3D67108707 > >> >=20 > >> > I suspect ee1de406ba6eb1 ("random: simplify accounting logic") as the > >> > culprit. > > Yep, that it's it. Thanks for noticing this so quickly! I'll push > > the following patch to Linus. >=20 > Peter, could you describe the infrastructure you're running on? I don't > think Dave or myself have ever hit this issue, and I wonder what made you > stumble on it. I'm running it on a WSP-EP, 2 nodes, 6 cores per node, 2 threads per core for a total of 24 cpus. I'm running trinity as user, and using: MALLOC_CHECK_=3D0 ./trinity -xinit_module -xreboot -xshutdown -xunshare -= xnfsservctl -xclock_nanosleep -xuselib -xumount -xmount -m --quiet -C 400 -= l off -xmremap to run it. I'm currently also running with syscall and a few other trace bits enabled, but I suppose that shouldn't affect things too much. The machine is running Debian wheezy with a few choice testing bits. --U4Pv8ouM+6WX/UB7 Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJTd5WvAAoJEHZH4aRLwOS6URYP/AwvNa5Sc1ILfUk1ka/B32Sa r9kZU45V761Q9BHJhCcbgnfAYHokLT1bIqfv09c4Q7XKgnCNK05f9oWRHxpfkMON 9aOMSnzzfq+oQlLgj4vgdhG0jHlR4CV/jVwgYasTPIBf1F0erV0tY9Cicd0VsvhL akm445dO2R5tFZ19V+/yc1uS6eky3T0jFkOsvGflj6yGokx69h3QceNUfmw7Eg1o HLFiF2Bx7zBS8K/BjLfewLwMH2gKMMtbnmlpc/IyM4+whdfUw5VQkit0M70sWaCu oC18P5U8gOcoOKJcTf+h91PC6MTXQIEe90KMaWn5MGHsVTV7CbbC2Sd4lzEMR7Dg kKxK9BSmuqAwSpuQJD1qn2mxRTgP+bjAfdNHazuSj6afotpqZtzL/gOny31o7/13 H41R9gzYYRgAZqBl9YNVa9PuEQY2TsGKNf2BxmDZfIRmRWPwOG9QnVqXQMJX2j75 D6s83zbCb+T8kHk7Z30oetNHN69+j09/MIZX73WAelK7CG/BwLQAHyUoO4DyuI6D ElhsbAcHJoDwvdppQPPuD/u8+rlP3BP8+1XoCwEs+xA8bXSdir2/Imc0xFqZswyt YfGjPGfgGVuZHB4OKC1oE0gBpcGZy4hTObhNgSC9ewLS+/Cy/+qSViSyeDf+qF1d iOt7vS/spC+s4CMkTH4h =c3Vc -----END PGP SIGNATURE----- --U4Pv8ouM+6WX/UB7--