linux-kernel - Re: kmemleak fails to report detected leaks after allocation failure

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Message-ID: <20110720083036.GG28726@e102109-lin.cambridge.arm.com>
Date:	Wed, 20 Jul 2011 09:30:36 +0100
From:	Catalin Marinas <catalin.marinas@....com>
To:	Nick Bowler <nbowler@...iptictech.com>
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>
Subject: Re: kmemleak fails to report detected leaks after allocation
 failure

On Tue, Jul 19, 2011 at 10:14:38PM +0100, Nick Bowler wrote:
> I just ran into a somewhat amusing issue with kmemleak.  After running
> for a while (10 days), and detecting about 100 "suspected memory leaks",
> kmemleak ultimately reported:
> 
>   kmemleak: Cannot allocate a kmemleak_object structure
>   kmemleak: Automatic memory scanning thread ended
>   kmemleak: Kernel memory leak detector disabled
> 
> OK, so something failed and kmemleak apparently can't recover from
> this.  However, at this point, it appears that kmemleak has *also*
> lost the ability to report the earlier leaks that it actually
> detected.
> 
>   cat: /sys/kernel/debug/kmemleak: Device or resource busy
> 
> It seems to me that kmemleak shouldn't lose the ability to report leaks
> that it already detected after it disables itself due to an issue that
> was potentially caused by the very leaks that it managed to detect
> (unlikely in this instance, but still...).

Very good point, I haven't thought of this. I'll try to improve this
part.

Thanks.

-- 
Catalin
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