From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758127Ab3G3IlO (ORCPT ); Tue, 30 Jul 2013 04:41:14 -0400 Received: from merlin.infradead.org ([205.233.59.134]:40185 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754432Ab3G3IlL (ORCPT ); Tue, 30 Jul 2013 04:41:11 -0400 Date: Tue, 30 Jul 2013 10:41:02 +0200 From: Peter Zijlstra To: Maarten Lankhorst Cc: Ingo Molnar , Linus Torvalds , Linux Kernel Mailing List , Thomas Gleixner , Andrew Morton , Dave Airlie , "dri-devel@lists.freedesktop.org" , Alex Deucher Subject: Re: [PATCH] mutex: fix deadlock injection Message-ID: <20130730084102.GI3008@twins.programming.kicks-ass.net> References: <20130701082221.GA14112@gmail.com> <51D3C4C8.8060701@canonical.com> <20130705062345.GA29487@gmail.com> <51F775B5.201@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51F775B5.201@canonical.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 30, 2013 at 10:13:41AM +0200, Maarten Lankhorst wrote: > The check needs to be for > 1, because ctx->acquired is already incremented. > This will prevent ww_mutex_lock_slow from returning -EDEADLK and not locking > the mutex. It caused a lot of false gpu lockups on radeon with > CONFIG_DEBUG_WW_MUTEX_SLOWPATH=y because a function that shouldn't be able > to return -EDEADLK did. > > Cc: Alex Deucher > Signed-off-by: Maarten Lankhorst Thanks!