Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758418Ab1CaPl6 (ORCPT ); Thu, 31 Mar 2011 11:41:58 -0400 Received: from mail-pv0-f174.google.com ([74.125.83.174]:38471 "EHLO mail-pv0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753146Ab1CaPl5 (ORCPT ); Thu, 31 Mar 2011 11:41:57 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; b=RVVLZSYwgRW887fBCRqlY8K5zc/ZjJgYRYPfoUQtiLaF4fYC0/zphteOGoTluqZndb NmaahEJOstbgAro9XFm/oPvtoyXLgnvvcnO9TsKimkk6e7niPltygOtaHlHJhq/cE8an I1CV9hpF9mwVdJaOgTBoQuBH1cMW+rdbz4HEs= Message-ID: <4D94A0C1.1060608@gmail.com> Date: Thu, 31 Mar 2011 08:41:53 -0700 From: "Justin P. Mattock" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.15) Gecko/20110316 Thunderbird/3.1.9 MIME-Version: 1.0 To: Florian Mickler CC: linux-kernel@vger.kernel.org, Steven Rostedt , Manjunatha Halli , Mauro Carvalho Chehab , Andrew Morton , Greg Kroah-Hartman Subject: Re: [BUG] NULL pointer dereference in dev_get_drvdata References: <1301448497.14261.319.camel@gandalf.stny.rr.com> <4D93508D.30701@gmail.com> <20110331111659.0c77abbe@schatten.dmk.lab> In-Reply-To: <20110331111659.0c77abbe@schatten.dmk.lab> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2154 Lines: 59 On 03/31/2011 02:16 AM, Florian Mickler wrote: > On Wed, 30 Mar 2011 08:47:25 -0700 > "Justin P. Mattock" wrote: > > >> >> strange thing with this, is one instance my screen went black, then >> something similar showed up on screen but then the screen kind of went >> back to normal(was able to move the mouse, but most of everything was >> frozen), another instance was shutting down the system pics are here: >> >> http://www.flickr.com/photos/44066293@N08/5573957179/ >> http://www.flickr.com/photos/44066293@N08/5574543648/ >> (not the best camara used) >> >> this does not fire off all the time, but it does. >> (I will keep my eye out with this one). >> >> Justin P. Mattock >> > > even with that resolution (240x320, that's a joke, right? do I need to > login or something like that?) I see that your stacktrace is > different. yeah... the iphone is only capable of so good of a picture. > > The stacktrace is the cascade of function-calls that lead to the > execution of the current code. A null-pointer in the driver-core > normally means that someone on the calling site did something wrong. > So in order to fix the bug, you have to look at the stack trace and > check how that null pointer got handed down to that function. > this was(I think) similar but not the same as dev_get_drvdata (all I know is this has fired off from time to time). > If you have 2 drivers. Both seperately calling the same function with a > nullpointer you have 2 seperate issues that trigger the same thing > (null pointer exception) in the same function. so it is not sufficient > to look at where the bug happened, you also need to check what is the > cause. > > Regards, > Flo > two drivers calling the same function(sounds bad!) this would be a race condition right? As for this message I will keep my eye out for anything in this area and report it to you guys. Justin P. Mattock -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/