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From: Thomas Gleixner <tglx@linutronix.de>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: rafael.j.wysocki@intel.com, peterz@infradead.org,
	riel@redhat.com, arjan@linux.intel.com, rusty@rustcorp.com.au,
	tj@kernel.org, srivatsa@mit.edu, torvalds@linux-foundation.org,
	bigeasy@linutronix.de, pjt@google.com, akpm@linux-foundation.org,
	hpa@zytor.com, oleg@redhat.com, mingo@kernel.org,
	linux-kernel@vger.kernel.org, rostedt@goodmis.org,
	linux-tip-commits@vger.kernel.org
Subject: Re: [tip:smp/hotplug] rcu: Make CPU_DYING_IDLE an explicit call
Date: Thu, 3 Mar 2016 08:31:35 +0100 (CET)	[thread overview]
Message-ID: <alpine.DEB.2.11.1603030830420.3597@nanos> (raw)
In-Reply-To: <20160302201127.GA23440@linux.vnet.ibm.com>

On Wed, 2 Mar 2016, Paul E. McKenney wrote:
> > --- a/kernel/cpu.c
> > +++ b/kernel/cpu.c
> > @@ -762,6 +762,7 @@ void cpuhp_report_idle_dead(void)
> >  	BUG_ON(st->state != CPUHP_AP_OFFLINE);
> >  	st->state = CPUHP_AP_IDLE_DEAD;
> >  	complete(&st->done);
> 
> Not to be repetitive or anything, but if we delay here, it can break
> RCU on a number of architectures.  Either the CPU can be killed holding
> one of RCU's locks or RCU can wrongly see the CPU as still being alive.
> Either can prevent future RCU grace periods from ever completing, thus
> OOMing the system.

Thanks for the reminder. I wanted to fix that, but then forgot again. Fix is
on the way.

Thanks,

	tglx

  reply	other threads:[~2016-03-03  7:33 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-26 18:43 [patch 00/20] cpu/hotplug: Core infrastructure for cpu hotplug rework Thomas Gleixner
2016-02-26 18:43 ` [patch 01/20] idle: Move x86ism out of generic code Thomas Gleixner
2016-02-27 20:29   ` Brian Gerst
2016-02-29 19:35     ` Thomas Gleixner
2016-02-29 19:48       ` Will Deacon
2016-02-29 20:06         ` Thomas Gleixner
2016-02-26 18:43 ` [patch 02/20] cpu/hotplug: Restructure FROZEN state handling Thomas Gleixner
2016-03-01 19:51   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-03-02 22:35     ` Srivatsa S. Bhat
2016-03-02 23:43     ` Srivatsa S. Bhat
2016-02-26 18:43 ` [patch 03/20] cpu/hotplug: Restructure cpu_up code Thomas Gleixner
2016-03-01 19:52   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-03-02 22:36     ` Srivatsa S. Bhat
2016-02-26 18:43 ` [patch 04/20] cpu/hotplug: Split out cpu down functions Thomas Gleixner
2016-03-01 19:52   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-03-02 22:37     ` Srivatsa S. Bhat
2016-02-26 18:43 ` [patch 05/20] cpu/hotplug: Add tracepoints Thomas Gleixner
2016-03-01 19:52   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-02-26 18:43 ` [patch 06/20] cpu/hotplug: Convert to a state machine for the control processor Thomas Gleixner
2016-03-01 19:53   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-03-02 11:23     ` Peter Zijlstra
2016-02-26 18:43 ` [patch 07/20] cpu/hotplug: Convert the hotplugged cpu work to a state machine Thomas Gleixner
2016-03-01 19:53   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-02-26 18:43 ` [patch 08/20] cpu/hotplug: Hand in target state to _cpu_up/down Thomas Gleixner
2016-03-01 19:54   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-02-26 18:43 ` [patch 09/20] cpu/hotplug: Add sysfs state interface Thomas Gleixner
2016-03-01 19:54   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-03-02 12:40     ` Peter Zijlstra
2016-02-26 18:43 ` [patch 10/20] cpu/hotplug: Make target state writeable Thomas Gleixner
2016-02-26 23:46   ` Rafael J. Wysocki
2016-02-27  7:39     ` Thomas Gleixner
2016-02-27 14:43       ` Rafael J. Wysocki
2016-02-28 14:49         ` Thomas Gleixner
2016-02-29 15:49           ` Thomas Gleixner
2016-03-01  1:53             ` Rafael J. Wysocki
2016-03-01 19:55   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-03-02 12:41     ` Peter Zijlstra
2016-03-02 19:57       ` Thomas Gleixner
2016-02-26 18:43 ` [patch 11/20] cpu/hotplug: Implement setup/removal interface Thomas Gleixner
2016-03-01 19:55   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-02-26 18:43 ` [patch 12/20] cpu/hotplug: Move scheduler cpu_online notifier to hotplug core Thomas Gleixner
2016-03-01 19:55   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-02-26 18:43 ` [patch 13/20] cpu/hotplug: Unpark smpboot threads from the state machine Thomas Gleixner
2016-03-01 19:56   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-02-26 18:43 ` [patch 14/20] cpu/hotplug: Split out the state walk into functions Thomas Gleixner
2016-03-01 19:56   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-02-26 18:43 ` [patch 15/20] cpu/hotplug: Create hotplug threads Thomas Gleixner
2016-03-01 19:57   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-02-26 18:43 ` [patch 16/20] cpu/hotplug: Move online calls to hotplugged cpu Thomas Gleixner
2016-03-01 19:57   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-02-26 18:43 ` [patch 17/20] arch/hotplug: Call into idle with a proper state Thomas Gleixner
2016-03-01 19:57   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-02-26 18:43 ` [patch 18/20] cpu/hotplug: Let upcoming cpu bring itself fully up Thomas Gleixner
2016-03-01 19:58   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-03-02 17:28   ` [patch 18/20] " Richard Cochran
2016-02-26 18:43 ` [patch 19/20] cpu/hotplug: Make wait for dead cpu completion based Thomas Gleixner
2016-03-01 19:58   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-02-26 18:43 ` [patch 20/20] rcu: Make CPU_DYING_IDLE an explicit call Thomas Gleixner
2016-02-27  2:14   ` Paul E. McKenney
2016-02-27  2:23     ` Paul E. McKenney
2016-02-27  7:47       ` Thomas Gleixner
2016-02-27 11:05         ` Paul E. McKenney
2016-02-27 11:30           ` Thomas Gleixner
2016-02-27 16:33             ` Paul E. McKenney
2016-03-01 19:58   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-03-02 20:11     ` Paul E. McKenney
2016-03-03  7:31       ` Thomas Gleixner [this message]
2016-03-03 10:03       ` [tip:smp/hotplug] cpu/hotplug: Plug death reporting race tip-bot for Thomas Gleixner
2016-03-03 14:11         ` Paul E. McKenney

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