From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755880Ab1JTBca (ORCPT ); Wed, 19 Oct 2011 21:32:30 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:35744 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754193Ab1JTBc3 (ORCPT ); Wed, 19 Oct 2011 21:32:29 -0400 Message-ID: <4E9F7A25.1060001@canonical.com> Date: Thu, 20 Oct 2011 09:32:21 +0800 From: Ike Panhc User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:7.0.1) Gecko/20110929 Thunderbird/7.0.1 MIME-Version: 1.0 To: David Rientjes CC: Sam Tygier , Matthew Garrett , linux-kernel@vger.kernel.org Subject: Re: 3.1rc10 null pointer dereference ideapad_backlight_notify_power References: <4E9EB1BC.9020709@yahoo.co.uk> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/20/2011 04:20 AM, David Rientjes wrote: > On Wed, 19 Oct 2011, Sam Tygier wrote: > >> In kernels 3.1rc9 and 3.1rc10 (from the ubuntu mainline repo) I get a crash >> when disabling and then enabling the screen backlight with the alt+f2 key on a >> lenovo ideapad S12 (intel version). The crash does not occur with 3.0 kernels >> in ubuntu. I have not tested earlier 3.1 rcs. >> >> The crash message scrolls to fast to see, it is not writen to a log, and i >> dont see it on a USB serial console (I may be doing something wrong, but I do >> see other messages during boot). I managed to get some photos of the message. >> interesting parts are: >> >> BUG: unable to handle kernel NULL pointer dereference at 00000008 >> IP: [] ideapad_backlight_notify_power+0x2e/0x40 [ideapad_laptop] >> *pde = 00000000 >> Oops: 0002 [#1] SMP >> >> call trace functions: >> ideapad_acpi_notify >> acpi_device_notify >> acpi_ev_notify_dispach >> acpi_os_execute_deferred >> process_one_work >> ? acpi_os_wait_events_complete >> ????????? can't read this one >> kthread >> kthread_bind >> kernel_thread_helper >> >> i put the photos at http://www.hep.manchester.ac.uk/u/sam/pub/ideapad/ >> >> if it would be helpfull, i could try a few more times for sharper photos. >> please let me know if there is any other useful information you need. >> > > Looks light it may be changed via the acpi video driver where ->blight is > NULL. Adding Ike and Matthew to the cc. > This issue has been reported[1] and patch[2] is ready. [1] http://www.mail-archive.com/platform-driver-x86@vger.kernel.org/msg02340.html [2] http://www.mail-archive.com/platform-driver-x86@vger.kernel.org/msg02343.html http://www.mail-archive.com/platform-driver-x86@vger.kernel.org/msg02346.html Thanks for reporting this issue.