From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760868AbXKNVox (ORCPT ); Wed, 14 Nov 2007 16:44:53 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753459AbXKNVoo (ORCPT ); Wed, 14 Nov 2007 16:44:44 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.31.123]:42564 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753072AbXKNVon (ORCPT ); Wed, 14 Nov 2007 16:44:43 -0500 Date: Wed, 14 Nov 2007 22:42:00 +0000 From: Pavel Machek To: "Rafael J. Wysocki" Cc: Andrew Morton , Johannes Berg , Peter Zijlstra , LKML , pm list Subject: Re: [PATCH] Hibernation: Fix lockdep report (v2) Message-ID: <20071114224200.GB7367@ucw.cz> References: <200711142225.58033.rjw@sisk.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <200711142225.58033.rjw@sisk.pl> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed 2007-11-14 22:25:57, Rafael J. Wysocki wrote: > [Andrew, please consider this as 2.6.24 material, thanks.] > --- > From: Johannes Berg > > Lockdep reports a circular locking dependency in the hibernate code > because >  - during system boot hibernate code (from an initcall) locks pm_mutex >    and then a sysfs buffer mutex via name_to_dev_t >  - during regular operation hibernate code locks pm_mutex under a >    sysfs buffer mutex because it's called from sysfs methods. > > The deadlock can never happen because during initcall invocation nothing > can write to sysfs yet. This removes the lockdep report by marking the > initcall locking as being in a different class. > > Signed-off-by: Johannes Berg > Cc: Alan Stern > Cc: Peter Zijlstra > Cc: Pavel Machek ACK... -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html