From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932104AbbAFQnk (ORCPT ); Tue, 6 Jan 2015 11:43:40 -0500 Received: from smtp2.provo.novell.com ([137.65.250.81]:58586 "EHLO smtp2.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753826AbbAFQnj (ORCPT ); Tue, 6 Jan 2015 11:43:39 -0500 Message-ID: <1420562614.24290.5.camel@stgolabs.net> Subject: Re: [PATCH] mutex: Always clear owner field upon mutex_unlock() From: Davidlohr Bueso To: Chris Wilson Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Ingo Molnar , Daniel Vetter Date: Tue, 06 Jan 2015 08:43:34 -0800 In-Reply-To: <1420540175-30204-1-git-send-email-chris@chris-wilson.co.uk> References: <1420540175-30204-1-git-send-email-chris@chris-wilson.co.uk> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.12.7 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2015-01-06 at 10:29 +0000, Chris Wilson wrote: > Currently if DEBUG_MUTEXES is enabled, the mutex->owner field is only > cleared iff debug_locks is active. This exposes a race to other users of > the field where the mutex->owner may be still set to a stale value, > potentially upsetting mutex_spin_on_owner() among others. > > References: https://bugs.freedesktop.org/show_bug.cgi?id=87955 > Signed-off-by: Chris Wilson > Cc: Peter Zijlstra > Cc: Ingo Molnar > Cc: Daniel Vetter Acked-by: Davidlohr Bueso