linux-kernel - Re: [RESEND PATCH] futex: fix key reference counter in case of requeue.

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Date:	Mon, 18 Oct 2010 14:14:15 +0200
From:	Matthieu Fertré <matthieu.fertre@...labs.com>
To:	Thomas Gleixner <tglx@...utronix.de>
CC:	Louis Rilling <louis.rilling@...labs.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Rusty Russell <rusty@...tcorp.com.au>,
	Ingo Molnar <mingo@...e.hu>, Darren Hart <darren@...art.com>,
	Peter Zijlstra <peterz@...radead.org>
Subject: Re: [RESEND PATCH] futex: fix key reference counter in case of	requeue.

Le 15/10/2010 14:16, Thomas Gleixner a écrit :
> On Thu, 14 Oct 2010, Louis Rilling wrote:
> 
>> From: Matthieu Fertré <matthieu.fertre@...labs.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
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