From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754227Ab2GNWTg (ORCPT ); Sat, 14 Jul 2012 18:19:36 -0400 Received: from smtp-2.hut.fi ([130.233.228.92]:50958 "EHLO smtp-2.hut.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752047Ab2GNWT2 (ORCPT ); Sat, 14 Jul 2012 18:19:28 -0400 Date: Sun, 15 Jul 2012 01:19:13 +0300 From: Sami Liedes To: Vegard Nossum Cc: Pekka Enberg , linux-kernel@vger.kernel.org Subject: Re: kmemcheck: Fatal error; system fails to boot when kmemcheck enabled Message-ID: <20120714221913.GA8653@sli.dy.fi> References: <20120712213305.GA11128@sli.dy.fi> <20120714010902.GA8741@sli.dy.fi> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="3V7upXqbjpZ4EhLz" Content-Disposition: inline In-Reply-To: <20120714010902.GA8741@sli.dy.fi> User-Agent: Mutt/1.5.21 (2010-09-15) X-TKK-Virus-Scanned: by amavisd-new-2.1.2-hutcc at katosiko.hut.fi Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --3V7upXqbjpZ4EhLz Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sat, Jul 14, 2012 at 04:09:02AM +0300, Sami Liedes wrote: > > Another thing you can try is try to figure out when things went wrong. > > If you test an old kernel like 3.0 or so -- and find that kmemcheck > > works, that's great, it means we have a way to narrow it down further. > > I may also try your config here to see if I can reproduce it. >=20 > I'll probably test 3.0 and could even try to git bisect within a few > days. I tested with 3.0.36. It does not boot either. Also, I tested with both 3.0.36 and 3.4.4 with kmemcheck=3D2. With that parameter, both boot fine. Curiously, when booting with kmemcheck=3D2, I can see absolutely no messages about kmemcheck, just as with kmemcheck=3D0, and the machine boots fine. The crashes happen only with kmemcheck=3D1. The speed suggests to me that with kmemcheck=3D2, kmemcheck is actually possibly not enabled at all for some reason. One curious result with 3.0.36: With nosmp, it panics so early that I'm unable to capture the dmesg (I may experiment with getting some other video mode than 80x25; not sure if it's possible...). *Without* nosmp, it boots much further, and I can actually get the dmesg via netconsole. I tried this a couple of times, with always the same result. Dmesg from 3.0.36 without nosmp: http://www.niksula.hut.fi/~sliedes/kmemcheck/nc.log.3.0.36 A photo of the (final portion of the) backtrace for 3.0.36 with nosmp: http://www.niksula.hut.fi/~sliedes/3.0.36.kmemcheck.nosmp.bt.jpg Dmesg from 3.4.4 with kmemcheck=3D2: http://www.niksula.hut.fi/~sliedes/kmemcheck/nc.log.3.4.4.kmemcheck-2 Dmesg from 3.0.36 with kmemcheck=3D2: http://www.niksula.hut.fi/~sliedes/kmemcheck/nc.log.3.0.36.kmemcheck-2 Sami --3V7upXqbjpZ4EhLz Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBCgAGBQJQAfBhAAoJEKLT589SE0a0HlcQAKiPl3JoYCghDB8vTMRsAoTO 029ZJMAFgTJyOj91sk0AMqgawFfIpCqhsUQnhkrPFU/vyPUDdz4/gldl9Rq3/jth P8K9xTS6W+C5SNCcx32Nmgd3nXrczBDamO8VxVm+N1CPHeqqR4H/mvMvjBJC21sb Z0PvVBD0FUFhUrEErjt6AAncXRUtORKEgo6qrsVoWYwpgz0bZ6ZNu9pDslzbma2d 2wUeO6p6C9+DP3DSMrTEvzTE8ZVL9DLC49xZo4ubcEiUkXfakml+8cFyLhJvCN+6 mhgmeF9/jcaTh8KQBsi4BX1+1TWjTx7NZ2BmRnMkFbyJjz25ne3L5NR9W/tQI8Pq WyRWi8vCMAQw07caylRF8BVJvwm5Nyaqf+LVMR4dYpgDL0HCz256rPY8InWbbbCQ txJVawlg9lpZwlpfAfJYhRNVYztgyBiiO0DtveDELqEG8JfeZ0dZrCTNQl7YK3rp Q3kZX7TgpgO1j6aFzCyE5YBTl7SGlR6zYIxiHvWlJipfxjBkWo3qKpM4PfIPPI6f /zBsW5buGcVcScuaYlx18bFSXaQcd4seHCd+8aEKQiwLnsmEM/BeaZimeUcfOigL dEboGNqK3gOv7A285Cy/VoPH3yZ36XTl5xUV5xQMIxBmtg82ngu+w/OyFt7WVgrD OloSiVcrq4WvAR0AzJRu =UxAA -----END PGP SIGNATURE----- --3V7upXqbjpZ4EhLz--