From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Milton Miller <miltonm@bga.com>,
akpm@linux-foundation.org, Anton Blanchard <anton@samba.org>,
xiaoguangrong@cn.fujitsu.com, mingo@elte.hu, jaxboe@fusionio.com,
npiggin@gmail.com, rusty@rustcorp.com.au,
torvalds@linux-foundation.org, paulmck@linux.vnet.ibm.com,
linux-kernel@vger.kernel.org
Subject: Re: call_function_many: fix list delete vs add race
Date: Tue, 01 Feb 2011 11:22:44 +1100 [thread overview]
Message-ID: <1296519764.2349.325.camel@pasglop> (raw)
In-Reply-To: <1296508677.26581.84.camel@laptop>
On Mon, 2011-01-31 at 22:17 +0100, Peter Zijlstra wrote:
> That's wrong:
>
> ->foo =
> LOCK
> UNLOCK
> ->bar =
>
> can be re-ordered as:
>
> LOCK
> ->bar =
> ->foo =
> UNLOCK
Can it ? I though UNLOCK had a write barrier semantic ? It does on power
at least :-) It should have since it shall prevent stores inside the
lock region to pass the store of the unlock itself anyways.
So yes, ->bar = can leak into the lock, as can ->foo =, but they can't
be re-ordered vs. each other because the implied barrier will keep ->foo
= in the same "domain" as the unlock itself.
Or do other archs do something really nasty here that don't provide this
guarantee ?
Cheers,
Ben.
next prev parent reply other threads:[~2011-02-01 0:23 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-12 4:07 [PATCH] smp_call_function_many SMP race Anton Blanchard
2011-01-17 18:17 ` Peter Zijlstra
2011-01-18 21:05 ` Milton Miller
2011-01-18 21:06 ` [PATCH 2/2] consolidate writes in smp_call_funtion_interrupt Milton Miller
2011-01-27 16:22 ` Peter Zijlstra
2011-01-27 21:59 ` Milton Miller
2011-01-29 0:20 ` call_function_many: fix list delete vs add race Milton Miller
2011-01-31 7:21 ` Mike Galbraith
2011-01-31 20:26 ` [PATCH] smp_call_function_many: handle concurrent clearing of mask Milton Miller
2011-02-01 3:15 ` Mike Galbraith
2011-01-31 10:27 ` call_function_many: fix list delete vs add race Peter Zijlstra
2011-01-31 20:26 ` Milton Miller
2011-01-31 20:39 ` Peter Zijlstra
2011-01-31 21:17 ` Peter Zijlstra
2011-01-31 21:36 ` Milton Miller
2011-02-01 0:22 ` Benjamin Herrenschmidt [this message]
2011-02-01 1:39 ` Linus Torvalds
2011-02-01 2:18 ` Paul E. McKenney
2011-02-01 2:43 ` Linus Torvalds
2011-02-01 4:45 ` Paul E. McKenney
2011-02-01 5:46 ` Linus Torvalds
2011-02-01 6:18 ` Benjamin Herrenschmidt
2011-02-01 14:13 ` Paul E. McKenney
2011-02-01 6:16 ` Benjamin Herrenschmidt
[not found] ` <ipi-list-reply@mdm.bga.com>
2011-02-01 7:12 ` [PATCH 1/3 v2] " Milton Miller
2011-02-01 22:00 ` Paul E. McKenney
2011-02-01 22:00 ` Milton Miller
2011-02-02 4:17 ` Paul E. McKenney
2011-02-06 23:51 ` Paul E. McKenney
2011-03-15 19:27 ` [PATCH 0/4 v3] smp_call_function_many issues from review Milton Miller
2011-03-15 20:22 ` Luck, Tony
2011-03-15 20:32 ` Dimitri Sivanich
2011-03-15 20:39 ` Peter Zijlstra
2011-03-16 17:55 ` Linus Torvalds
2011-03-16 18:13 ` Peter Zijlstra
2011-03-17 3:15 ` Mike Galbraith
2011-02-07 8:12 ` [PATCH 1/3 v2] call_function_many: fix list delete vs add race Mike Galbraith
2011-02-08 19:36 ` Paul E. McKenney
2011-08-21 6:17 ` Mike Galbraith
2011-02-02 6:22 ` Mike Galbraith
2011-02-01 7:12 ` [PATCH 2/3 v2] smp_call_function_many: handle concurrent clearing of mask Milton Miller
2011-03-15 19:27 ` [PATCH 2/4 v3] call_function_many: add missing ordering Milton Miller
2011-03-16 12:06 ` Paul E. McKenney
2011-03-15 19:27 ` [PATCH 1/4 v3] call_function_many: fix list delete vs add race Milton Miller
2011-03-15 19:27 ` [PATCH 4/4 v3] smp_call_function_interrupt: use typedef and %pf Milton Miller
2011-03-15 19:27 ` [PATCH 3/4 v3] smp_call_function_many: handle concurrent clearing of mask Milton Miller
2011-03-15 22:32 ` Catalin Marinas
2011-03-16 7:52 ` Jan Beulich
2011-01-18 21:07 ` [PATCH 1/2] smp_call_function_many SMP race Milton Miller
2011-01-20 0:41 ` Andrew Morton
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