linux-kernel - Re: [PATCH 05/15] kmemleak: Add the slub memory allocation/freeing hooks

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Message-ID: <494A74CA.7060403@cs.helsinki.fi>
Date:	Thu, 18 Dec 2008 18:05:30 +0200
From:	Pekka Enberg <penberg@...helsinki.fi>
To:	Catalin Marinas <catalin.marinas@....com>
CC:	linux-kernel@...r.kernel.org,
	Christoph Lameter <cl@...ux-foundation.org>
Subject: Re: [PATCH 05/15] kmemleak: Add the slub memory allocation/freeing
 hooks

Hi Catalin,

Catalin Marinas wrote:
> Just to make sure I understand it correctly, the slab_free() fast path
> stores the pointer to the freed object into c->freelist. However, this
> object is no longer tracked by kmemleak because of the
> kmemleak_free_recursive() call at the beginning of this function (false
> negatives make sense only for allocated objects).

Indeed. For SLAB, it's a problem because the per-CPU cache pointer is 
not cleared from the struct array_cache upon _allocation_ which is the 
culprit of the false negative there.

Catalin Marinas wrote:
> Is my understanding correct? Thanks.

Yes, it is and I was just confused. Thanks!

		Pekka
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