From: Mike Galbraith <umgwanakikbuti@gmail.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Nicholas Mc Guire <der.herr@hofr.at>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
linux-rt-users <linux-rt-users@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
John Kacur <jkacur@redhat.com>
Subject: Re: [ANNOUNCE] 3.14-rt1
Date: Mon, 28 Apr 2014 16:37:12 +0200 [thread overview]
Message-ID: <1398695832.14475.10.camel@marge.simpson.net> (raw)
In-Reply-To: <20140428101805.75032f45@gandalf.local.home>
On Mon, 2014-04-28 at 10:18 -0400, Steven Rostedt wrote:
> On Mon, 28 Apr 2014 11:09:46 +0200
> Mike Galbraith <umgwanakikbuti@gmail.com> wrote:
>
> > migrate_disable-pushd-down-in-atomic_dec_and_spin_lo.patch
> >
> > bug: migrate_disable() after blocking is too late.
> >
> > @@ -1028,12 +1028,12 @@ int atomic_dec_and_spin_lock(atomic_t *a
> > /* Subtract 1 from counter unless that drops it to 0 (ie. it was 1) */
> > if (atomic_add_unless(atomic, -1, 1))
> > return 0;
> > - migrate_disable();
> > rt_spin_lock(lock);
> > - if (atomic_dec_and_test(atomic))
> > + if (atomic_dec_and_test(atomic)){
> > + migrate_disable();
>
> Makes sense, as the CPU can go offline right after the lock is grabbed
> and before the migrate_disable() is called.
>
> Seems that migrate_disable() must be called before taking the lock as
> it is done in every other location.
And for tasklist_lock, seems you also MUST do that prior to trylock as
well, else you'll run afoul of the hotplug beast.
-Mike
next prev parent reply other threads:[~2014-04-28 14:37 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-11 18:57 [ANNOUNCE] 3.14-rt1 Sebastian Andrzej Siewior
2014-04-11 19:34 ` Pavel Vasilyev
2014-04-19 14:46 ` Mike Galbraith
2014-04-21 3:31 ` Mike Galbraith
2014-05-02 10:16 ` Sebastian Andrzej Siewior
2014-04-25 7:40 ` Mike Galbraith
2014-04-26 8:38 ` Mike Galbraith
2014-04-26 13:58 ` Mike Galbraith
2014-04-28 5:09 ` Mike Galbraith
2014-04-28 9:09 ` Mike Galbraith
2014-04-28 14:18 ` Steven Rostedt
2014-04-28 14:37 ` Mike Galbraith [this message]
2014-04-28 14:43 ` Mike Galbraith
2014-04-29 5:21 ` Mike Galbraith
2014-04-30 0:13 ` Steven Rostedt
2014-04-30 7:43 ` Mike Galbraith
2014-04-30 13:06 ` Mike Galbraith
2014-04-30 13:15 ` Steven Rostedt
2014-04-30 14:00 ` Mike Galbraith
2014-04-30 14:19 ` Steven Rostedt
2014-04-30 14:33 ` Steven Rostedt
2014-04-30 14:54 ` Mike Galbraith
2014-04-30 15:11 ` Steven Rostedt
2014-04-30 15:15 ` Mike Galbraith
2014-04-30 15:48 ` Steven Rostedt
2014-04-30 15:56 ` Mike Galbraith
2014-05-01 17:36 ` Mike Galbraith
2014-05-01 18:42 ` Steven Rostedt
2014-05-02 1:45 ` Mike Galbraith
2014-04-30 15:21 ` Mike Galbraith
2014-04-30 14:45 ` Mike Galbraith
2014-05-02 10:09 ` Sebastian Andrzej Siewior
2014-05-02 11:16 ` Mike Galbraith
2014-04-23 10:37 ` Mike Galbraith
2014-04-23 12:19 ` Steven Rostedt
2014-04-24 4:06 ` Mike Galbraith
2014-04-24 7:12 ` Sebastian Andrzej Siewior
2014-04-24 7:26 ` Mike Galbraith
2014-04-26 18:29 ` Fernando Lopez-Lezcano
2014-05-02 11:37 ` Sebastian Andrzej Siewior
2014-05-15 17:51 ` Fernando Lopez-Lezcano
2014-05-15 20:09 ` Fernando Lopez-Lezcano
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