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From: "Matthieu Fertré" <matthieu.fertre@kerlabs.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Louis Rilling <louis.rilling@kerlabs.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Rusty Russell <rusty@rustcorp.com.au>,
	Ingo Molnar <mingo@elte.hu>, Darren Hart <darren@dvhart.com>,
	Peter Zijlstra <peterz@infradead.org>
Subject: Re: [RESEND PATCH] futex: fix key reference counter in case of	requeue.
Date: Mon, 18 Oct 2010 14:14:15 +0200	[thread overview]
Message-ID: <4CBC3A17.2080306@kerlabs.com> (raw)
In-Reply-To: <alpine.LFD.2.00.1010151228130.2496@localhost6.localdomain6>

Le 15/10/2010 14:16, Thomas Gleixner a écrit :
> On Thu, 14 Oct 2010, Louis Rilling wrote:
> 
>> From: Matthieu Fertré <matthieu.fertre@kerlabs.com>
>>
>> This patch ensures that we are referring to the right key when dropping
>> reference for the futex_wait operation.
>>
>> The following scenario explains a typical case where the bug was
>> happening:
>>
>> Process P calls futex_wait() on futex identified by 'key1'. 2 references
>> are taken on this key: one for the struct futex_q itself, and one for the
>> futex_wait operation.
> 
> It took a while to understand that explanation. You mean we get one
> ref in get_key_ref() and one in queue_lock(), right ?
> 

That's it. Sorry for the unclear explanation.

Regards,

Matthieu

  parent reply	other threads:[~2010-10-18 12:19 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-14 11:30 [RESEND PATCH] futex: fix key reference counter in case of requeue Louis Rilling
2010-10-15 12:16 ` Thomas Gleixner
2010-10-15 19:19   ` Darren Hart
2010-10-18 12:14   ` Matthieu Fertré [this message]
2010-10-15 19:13 ` Darren Hart
2010-10-15 19:18   ` Thomas Gleixner
2010-10-18 12:51   ` Matthieu Fertré

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