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From: Catalin Marinas <catalin.marinas@arm.com>
To: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Vegard Nossum <vegard.nossum@gmail.com>,
	Ingo Molnar <mingo@elte.hu>,
	linux-kernel@vger.kernel.org
Subject: Re: WARNING: kmemcheck: Caught 32-bit read from uninitialized memory  (f6f6e1a4), by kmemleak's scan_block()
Date: Tue, 25 Aug 2009 10:28:54 +0100	[thread overview]
Message-ID: <1251192534.15678.29.camel@pc1117.cambridge.arm.com> (raw)
In-Reply-To: <1251192415.26351.5.camel@penberg-laptop>

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@arm.com>

-- 
Catalin


  reply	other threads:[~2009-08-25  9:29 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-08-25  7:19 WARNING: kmemcheck: Caught 32-bit read from uninitialized memory (f6f6e1a4), by kmemleak's scan_block() Ingo Molnar
2009-08-25  8:04 ` Vegard Nossum
2009-08-25  8:08   ` Pekka Enberg
2009-08-25  8:27     ` Catalin Marinas
2009-08-25  8:31       ` Pekka Enberg
2009-08-25  8:40         ` Ingo Molnar
2009-08-25  8:48           ` Pekka Enberg
2009-08-25  8:32   ` Ingo Molnar
2009-08-25  8:45     ` Pekka Enberg
2009-08-25  8:48       ` Ingo Molnar
2009-08-25  8:54         ` Pekka Enberg
2009-08-25  9:03           ` Vegard Nossum
2009-08-25  9:11             ` Catalin Marinas
2009-08-25  9:15               ` Pekka Enberg
2009-08-25  9:25                 ` Catalin Marinas
2009-08-25  9:11             ` Pekka Enberg
2009-08-25  9:21               ` Catalin Marinas
2009-08-25  9:26                 ` Pekka Enberg
2009-08-25  9:28                   ` Catalin Marinas [this message]
2009-08-25  9:31                     ` Pekka Enberg
2009-08-25  9:34                       ` Catalin Marinas
2009-08-25  9:34                       ` Ingo Molnar
2009-08-25 10:43                         ` Ingo Molnar
2009-08-25 13:57                           ` Catalin Marinas
2009-08-26 10:48                         ` Pekka Enberg
2009-08-26 11:17                           ` Ingo Molnar
2009-08-25  9:25               ` Ingo Molnar

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