From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755574Ab0IUDGu (ORCPT ); Mon, 20 Sep 2010 23:06:50 -0400 Received: from mail-wy0-f174.google.com ([74.125.82.174]:36759 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753142Ab0IUDGt (ORCPT ); Mon, 20 Sep 2010 23:06:49 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=subject:from:to:content-type:date:message-id:mime-version:x-mailer; b=ozmKzIp7CvBNlSbeeUbnrSlQe1OphJT4jj5UeTIxXYYB1AWHPBZSYWZNCj+OFHFhTn TAhFaE8sYmKSHeHAxOPBemFXd/EkcSlhRrkM9Id4l7U0r7vXCMoeXNneIXYSDB89KmaA fNKAFFIF7tJUeBT8IqlfaiudxVtk0ogTpPnJw= Subject: How to debug system hangs (bug #15737) on start of composite WM From: Maciej Piechotka To: linux-kernel@vger.kernel.org Content-Type: multipart/signed; micalg="pgp-ripemd160"; protocol="application/pgp-signature"; boundary="=-RipcffliihYf8rJqsBs9" Date: Tue, 21 Sep 2010 04:06:26 +0100 Message-ID: <1285038386.3269.4.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.31.91 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-RipcffliihYf8rJqsBs9 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable I have problems debugging system hangs (bug #15737 - https://bugzilla.kernel.org/show_bug.cgi?id=3D15737) which occur on kernels >=3D2.6.33 (LTS i.e. 2.6.32 is not affected).=20 I cannot manage to debug them especially it actual results evolve along with changes in userspace (however 2.6.32 is not affected). On various stages: - Second start of composite WM would be either hard hang or will fix the system (i.e. problem will not be reproduced until next reboot - and will not be reproduced after hibernation) - recently (for 2 weeks) false - First start of X will result in soft hang only - true except some builds of 2.6.35 with relocatable kernel (???) and very old builds (2.6.33) - Magic SysRQ key does not work on hard hang - If second start of WM was successful the DRI after some time will report bad drawables. It is fixed by reboot - recent (for 2 weeks) - Switching to console and back helps (i.e. more often there is no hang) - possibly voodoo magic but it may help - Error messages about failing to pinpoint buffor (cause? side-effect?) - Running X in gdb hangs system (even if it is not on current VT) Soft hang: X hangs but I can switch to console. Turning off X will stop it but it takes some time (a minute?). There is nothing in logs (X, dmesg, system...) Hard hang: System is not responsive including network, X, sysrq etc. This is not kernel panic (caps lock and num lock does not blink). Someone (probably not kernel dev) suggested that it might be connected with removing BKL. I am really sorry for spamming but I run out of ideas how to debug this problem. Regards --=-RipcffliihYf8rJqsBs9 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.16 (GNU/Linux) iQIcBAABAwAGBQJMmCEyAAoJEJIdee2Vr4aPd7AP/R/5Ac9ugpceK+0pq560WL8N rzgc/KcEiwa4hS4yPzCE8SkYw9rQbQLK7+tN26VJcH4h+OGFeesOGLdWxRVnvuBD Nas+cPh3q176J0pfiGaPOCphVg2AoAAg2TfidjI37Q4Jb8ts7uD5rjtL/lsGyKNh JaaY3/Jko8jEge+r+2haMQMqdUoZmiG/YeLEOnOfNyCSjEaibJB/zZRYXsiGo9fm 5txWIRRKUaGKR7TWRCz6XPgcQ57FWwCRtPVZ5mVvW/UzMb01agDAzd2vJ9MZsUVv jMA6tkvFHAcQoWfla0g4XlzP4UXkJIOL+vu10cBpuL/EFlZQCDKqIOEsD6FnVVLu HuQuhF+sKhnP98+mYPf9zpBT1jvq/osh6DBmZU7ybduz/UCCQELmpWii8ATgOX5U GrA7nkBFMm/Cn5bILDQxhXgOunAzoc1Swr6KeY3l6cflClUNl12zomjwZQ4J67kK uaYG1/rDL0SAOCf1SS4zQPKozIxRpBIz3vcenlqKBHlxIVYZ9Snm685ML6iMm3b2 dghN9bopsB9yzhQ+NzoCS7qLlCtkPkYdrxUg2j7jkX+3EEsb9WQeWXEr+6aYj44D uLBfhe2WqT7fkEa1kpAu1+jtGm9KWrqca9nivdE8kxC6zutm77YwsvPQuWA3h46b 9AG/TqVvdA9QdqDb3d31 =8FAH -----END PGP SIGNATURE----- --=-RipcffliihYf8rJqsBs9--