linux-kernel - Re: Possible kmemleak issue, but I'm confused

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Message-ID: <4C7544FA.5030304@am.sony.com>
Date:	Wed, 25 Aug 2010 09:29:46 -0700
From:	Tim Bird <tim.bird@...sony.com>
To:	Catalin Marinas <catalin.marinas@....com>
CC:	linux kernel <linux-kernel@...r.kernel.org>
Subject: Re: Possible kmemleak issue, but I'm confused

On 08/25/2010 02:19 AM, Catalin Marinas wrote:
>> What is the status of this patch relative to linux-next or Linus'
>> tree?
> 
> This patch was merged in 2.6.31-rc1 but parts of it were later dropped
> in 2.6.34-rc1 (commit 23fb064b) when Tejun removed the legacy percpu
> allocator. The new percpu allocator in mm/percpu.c uses standard
> allocation methods like alloc_bootmem or kzalloc and kmemleak handles
> these already, so no need for extra code in kernel/module.c.

OK.  This is just the information I needed.  Thanks.

>> Our solution was just to make these specific calls to kmemleak_alloc
>> and kmemleak_free (in module.c) compile-time configurable.
>> I suspect that there is a better way to do this -- possibly by
>> detecting or noting that this situation exists for certain
>> platforms, and avoiding it without specific user interaction.
> 
> For the 2.6.29 kernel (not mainline), you could have it compile-time
> configurable. Another option would be to hack create_object() in
> mm/kmemleak.c to not call kmemleak_stop("Cannot insert ..."), though
> this method could potentially hide other problems with kmemleak
> callbacks.

We'll stick with our compile-time option, then, and it sounds
like when we upgrade our kernel version we won't need to worry
about this issue.

Thanks very much!  kmemleak is cool. :-)
 -- Tim


=============================
Tim Bird
Architecture Group Chair, CE Linux Forum
Senior Staff Engineer, Sony Network Entertainment
=============================

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