linux-kernel - Re: WARNING: kmemcheck: Caught 32-bit read from uninitialized memory (f6f6e1a4), by kmemleak's scan

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Message-Id: <1251192534.15678.29.camel@pc1117.cambridge.arm.com>
Date:	Tue, 25 Aug 2009 10:28:54 +0100
From:	Catalin Marinas <catalin.marinas@....com>
To:	Pekka Enberg <penberg@...helsinki.fi>
Cc:	Vegard Nossum <vegard.nossum@...il.com>,
	Ingo Molnar <mingo@...e.hu>, linux-kernel@...r.kernel.org
Subject: Re: WARNING: kmemcheck: Caught 32-bit read from uninitialized
	memory  (f6f6e1a4), by kmemleak's scan_block()

On Tue, 2009-08-25 at 12:26 +0300, Pekka Enberg wrote:
> On Tue, 2009-08-25 at 10:21 +0100, Catalin Marinas wrote:
> > On Tue, 2009-08-25 at 12:11 +0300, Pekka Enberg wrote:
> > > On Tue, 2009-08-25 at 11:03 +0200, Vegard Nossum wrote:
> > > > I don't know so much about the kmemleak internals, but this I can say
> > > > about the kmemcheck part: According to your definition, an object is
> > > > initialized if all the bytes of an object are initialized.
> > > > 
> > > > Is it possible that because of this, if we have a partially
> > > > uninitialized object, kmemleak will not record the pointers found in
> > > > that object? If so, it might skip valid pointers, and deem an object
> > > > unreferenced. Which could make kmemleak give false-positives.
> > > > 
> > > > I think it would be better to ask kmemcheck on a per-pointer basis
> > > > (i.e. for each pointer-sized word in the object), whether it is
> > > > initialized or not.
> > > 
> > > Yeah, makes sense.
> > 
> > I think this patch should work. With a few minor (aesthetic) things
> > below and assuming that Ingo tests it (I don't have x86 hardware at hand
> > now):
> 
> Does this look OK to you?

For the kmemleak.c part:

Acked-by: Catalin Marinas <catalin.marinas@....com>

-- 
Catalin

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