linux-kernel - Re: [PATCH 04/19] sched: Prepare for Core-wide rq->lock

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <YJPEM1DPrG2zlvY0@hirez.programming.kicks-ass.net>
Date:   Thu, 6 May 2021 12:25:55 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Don Hiatt <dhiatt@...italocean.com>
Cc:     Josh Don <joshdon@...gle.com>, Aubrey Li <aubrey.intel@...il.com>,
        Joel Fernandes <joel@...lfernandes.org>,
        "Hyser,Chris" <chris.hyser@...cle.com>,
        Ingo Molnar <mingo@...nel.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Valentin Schneider <valentin.schneider@....com>,
        Mel Gorman <mgorman@...e.de>,
        Linux List Kernel Mailing <linux-kernel@...r.kernel.org>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH 04/19] sched: Prepare for Core-wide rq->lock

On Wed, May 05, 2021 at 09:20:38AM -0700, Don Hiatt wrote:
> On Tue, May 4, 2021 at 12:38 AM Peter Zijlstra <peterz@...radead.org> wrote:
> >
> > On Thu, Apr 29, 2021 at 01:39:54PM -0700, Josh Don wrote:
> >
> > > > > +void double_rq_lock(struct rq *rq1, struct rq *rq2)
> > > > > +{
> > > > > +       lockdep_assert_irqs_disabled();
> > > > > +
> > > > > +       if (rq1->cpu > rq2->cpu)
> > > >
> > > > It's still a bit hard for me to digest this function, I guess using (rq->cpu)
> > > > can't guarantee the sequence of locking when coresched is enabled.
> > > >
> > > > - cpu1 and cpu7 shares lockA
> > > > - cpu2 and cpu8 shares lockB
> > > >
> > > > double_rq_lock(1,8) leads to lock(A) and lock(B)
> > > > double_rq_lock(7,2) leads to lock(B) and lock(A)
> >
> > Good one!
> 
> Hi Peter,
> 
> I've been running the same set-cookie tests on your latest repo for
> the last 24 hours and haven't had a single lockup. Thank you very
> much!

Excellent, applied your Tested-by, thanks!