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From: Thomas Gleixner <tglx@linutronix.de>
To: paulmck@kernel.org, Marco Elver <elver@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	LKML <linux-kernel@vger.kernel.org>,
	kasan-dev <kasan-dev@googlegroups.com>,
	Ingo Molnar <mingo@kernel.org>,
	Frederic Weisbecker <frederic@kernel.org>,
	Will Deacon <will@kernel.org>,
	Naresh Kamboju <naresh.kamboju@linaro.org>,
	syzbot+23a256029191772c2f02@syzkaller.appspotmail.com,
	syzbot+56078ac0b9071335a745@syzkaller.appspotmail.com,
	syzbot+867130cb240c41f15164@syzkaller.appspotmail.com
Subject: Re: [patch 3/3] tick: Annotate tick_do_timer_cpu data races
Date: Mon, 07 Dec 2020 22:46:33 +0100	[thread overview]
Message-ID: <87blf547d2.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20201207194406.GK2657@paulmck-ThinkPad-P72>

On Mon, Dec 07 2020 at 11:44, Paul E. McKenney wrote:
> On Mon, Dec 07, 2020 at 07:19:51PM +0100, Marco Elver wrote:
>> On Mon, 7 Dec 2020 at 18:46, Thomas Gleixner <tglx@linutronix.de> wrote:
>> I currently don't know what the rule for Peter's preferred variant
>> would be, without running the risk of some accidentally data_race()'d
>> accesses.
>> 
>> Thoughts?
>
> I am also concerned about inadvertently covering code with data_race().
>
> Also, in this particular case, why data_race() rather than READ_ONCE()?
> Do we really expect the compiler to be able to optimize this case
> significantly without READ_ONCE()?

That was your suggestion a week or so ago :)

Thanks,

        tglx

  reply	other threads:[~2020-12-07 21:47 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-06 21:12 [patch 0/3] tick: Annotate and document the intentionaly racy tick_do_timer_cpu Thomas Gleixner
2020-12-06 21:12 ` [patch 1/3] tick: Remove pointless cpu valid check in hotplug code Thomas Gleixner
2020-12-07 11:59   ` Peter Zijlstra
2020-12-07 17:44     ` Thomas Gleixner
2020-12-11 22:21   ` Frederic Weisbecker
2020-12-12  0:16     ` Thomas Gleixner
2020-12-12  1:20       ` Frederic Weisbecker
2020-12-11 22:31   ` Frederic Weisbecker
2020-12-16 10:50   ` [tip: timers/urgent] " tip-bot2 for Thomas Gleixner
2020-12-06 21:12 ` [patch 2/3] tick/sched: Remove bogus boot "safety" check Thomas Gleixner
2020-12-11 22:41   ` Frederic Weisbecker
2020-12-16 10:50   ` [tip: timers/urgent] " tip-bot2 for Thomas Gleixner
2020-12-06 21:12 ` [patch 3/3] tick: Annotate tick_do_timer_cpu data races Thomas Gleixner
2020-12-07 12:09   ` Peter Zijlstra
2020-12-07 17:46     ` Thomas Gleixner
2020-12-07 18:19       ` Marco Elver
2020-12-07 19:43         ` Thomas Gleixner
2020-12-07 19:44         ` Paul E. McKenney
2020-12-07 21:46           ` Thomas Gleixner [this message]
2020-12-07 22:38             ` Paul E. McKenney
2020-12-07 22:46               ` Thomas Gleixner
2020-12-07 22:55                 ` Paul E. McKenney
2020-12-08  8:11           ` Peter Zijlstra
2020-12-08 15:03             ` Paul E. McKenney
2020-12-16  0:27               ` Thomas Gleixner
2020-12-16 21:19                 ` Paul E. McKenney
2020-12-16 21:23                   ` Thomas Gleixner
2020-12-16 21:32                     ` Paul E. McKenney
2020-12-17 10:48                   ` Peter Zijlstra
2020-12-17 14:59                     ` Paul E. McKenney
2020-12-08  8:01         ` Peter Zijlstra
2020-12-07 11:05 ` [patch 0/3] tick: Annotate and document the intentionaly racy tick_do_timer_cpu Marco Elver

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