From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1751508AbdAMWZX (ORCPT <rfc822;w@1wt.eu>);
        Fri, 13 Jan 2017 17:25:23 -0500
Received: from mx1.redhat.com ([209.132.183.28]:54714 "EHLO mx1.redhat.com"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1751232AbdAMWZW (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Fri, 13 Jan 2017 17:25:22 -0500
Message-ID: <1484346315.5606.313.camel@redhat.com>
Subject: Re: Robust futexes: lost wakeups and design flaws in the
 glibc/kernel synchronization scheme
From: Torvald Riegel <triegel@redhat.com>
To: LKML <linux-kernel@vger.kernel.org>
Cc: GLIBC Devel <libc-alpha@sourceware.org>,
        "Zijlstra, Peter" <peter.zijlstra@intel.com>,
        Thomas Gleixner <tglx@linutronix.de>, Rich Felker <dalias@libc.org>
Date: Fri, 13 Jan 2017 23:25:15 +0100
In-Reply-To: <1484213984.5606.272.camel@redhat.com>
References: <1482595274.3038.35.camel@redhat.com>
         <1484213984.5606.272.camel@redhat.com>
Content-Type: text/plain; charset="UTF-8"
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Fri, 13 Jan 2017 22:25:22 +0000 (UTC)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Thu, 2017-01-12 at 10:39 +0100, Torvald Riegel wrote:
> On Sat, 2016-12-24 at 17:01 +0100, Torvald Riegel wrote:
> > === Robust mutexes have bugs, in both glibc and the kernel
> > 
> > I've been reviewing the implementation of robust mutexes in both glibc
> > and the kernel support code recently because there are several bug
> > reports, for example:
> > https://bugzilla.redhat.com/show_bug.cgi?id=1401665
> > https://sourceware.org/bugzilla/show_bug.cgi?id=19402
> > https://sourceware.org/bugzilla/show_bug.cgi?id=14485
> > 
> > This review revealed a bunch of bugs.  I have committed/proposed patches
> > that fix all glibc-only bugs that I am aware of:
> > https://sourceware.org/ml/libc-alpha/2016-12/msg00587.html
> > https://sourceware.org/ml/libc-alpha/2016-12/msg00862.html
> > https://sourceware.org/ml/libc-alpha/2016-12/msg00863.html
> > https://sourceware.org/ml/libc-alpha/2016-12/msg00947.html

These patches are now all committed to glibc master.  Thus, you can
start fixing/testing now and have a high probability that you won't run
into glibc bugs.