Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753941Ab0ADXEo (ORCPT ); Mon, 4 Jan 2010 18:04:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753638Ab0ADXEn (ORCPT ); Mon, 4 Jan 2010 18:04:43 -0500 Received: from hera.kernel.org ([140.211.167.34]:57544 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753051Ab0ADXEm (ORCPT ); Mon, 4 Jan 2010 18:04:42 -0500 Message-ID: <4B427547.5070109@kernel.org> Date: Tue, 05 Jan 2010 08:09:59 +0900 From: Tejun Heo User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.5) Gecko/20091130 SUSE/3.0.0-1.1.1 Thunderbird/3.0 MIME-Version: 1.0 To: "Eric W. Biederman" CC: Dmitry Torokhov , Linus Torvalds , KOSAKI Motohiro , Borislav Petkov , David Airlie , Linux Kernel Mailing List , Greg KH , Al Viro Subject: Re: drm_vm.c:drm_mmap: possible circular locking dependency detected References: <4B3EB687.7000005@kernel.org> <4B3FE586.7020109@kernel.org> <20100103074745.GA2314@core.coreip.homeip.net> <20100104185755.GB2597@core.coreip.homeip.net> In-Reply-To: X-Enigmail-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 959 Lines: 24 Hello, On 01/05/2010 04:43 AM, Eric W. Biederman wrote: >>> So it is unlikely but possible to deadlock by accessing a serio >>> attribute of a serio device that is being removed. >> >> Hmm, I guess I was too quick dismissing lockdep complaints here. Now >> that sysfs remove waits deadlock indeed is possible. Actually the locks >> on serio->drv_mutex in attributes were added to make sure we don't >> access device that was unbound from the driver through stale sysfs >> attributes. > > Cool. So we have solved the problem generically but we have left over > layer specific solutions. That seems like a good problem to have. This is way too cool. Only if we can have more moments like this. :-) -- tejun -- 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/