linux-kernel - Re: [PATCH v2] membarrier: Document scheduler barrier requirements

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-Id: <20170822062022.GZ11320@linux.vnet.ibm.com>
Date:   Mon, 21 Aug 2017 23:20:22 -0700
From:   "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        linux-kernel@...r.kernel.org, Boqun Feng <boqun.feng@...il.com>,
        Andrew Hunter <ahh@...gle.com>,
        Maged Michael <maged.michael@...il.com>, gromer@...gle.com,
        Avi Kivity <avi@...lladb.com>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Dave Watson <davejwatson@...com>
Subject: Re: [PATCH v2] membarrier: Document scheduler barrier requirements

On Mon, Aug 21, 2017 at 10:42:36AM +0200, Peter Zijlstra wrote:
> On Fri, Aug 18, 2017 at 09:39:16PM -0700, Mathieu Desnoyers wrote:
> > @@ -3295,6 +3301,9 @@ static void __sched notrace __schedule(bool preempt)
> >  	 * Make sure that signal_pending_state()->signal_pending() below
> >  	 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
> >  	 * done by the caller to avoid the race with signal_wake_up().
> > +	 *
> > +	 * The membarrier system call requires a full memory barrier
> > +	 * after coming from user-space, before storing to rq->curr.
> >  	 */
> >  	smp_mb__before_spinlock();
> >  	rq_lock(rq, &rf);
> 
> Merge conflict here, current tip is over to smp_mb__after_spinlock().

Would some tree other than -rcu be better for that commit?

							Thanx, Paul