Subject: Re: [RFC PATCH 2/3] kmemleak: Add callbacks to the bootmem
 allocator
From: Pekka Enberg <penberg@cs.helsinki.fi>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>, linux-mm@kvack.org,
       linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>
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	 <1247004586.5710.16.camel@pc1117.cambridge.arm.com>
Date: Wed, 08 Jul 2009 09:48:21 +0300
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Hi Catalin,

On Tue, 2009-07-07 at 23:09 +0100, Catalin Marinas wrote:
> On Tue, 2009-07-07 at 18:53 +0200, Johannes Weiner wrote:
> > On Tue, Jul 07, 2009 at 10:08:50AM +0300, Pekka Enberg wrote:
> > > On Mon, 2009-07-06 at 11:51 +0100, Catalin Marinas wrote:
> > > > @@ -597,7 +601,9 @@ restart:
> > > >  void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align,
> > > >  					unsigned long goal)
> > > >  {
> > > > -	return ___alloc_bootmem_nopanic(size, align, goal, 0);
> > > > +	void *ptr =  ___alloc_bootmem_nopanic(size, align, goal, 0);
> > > > +	kmemleak_alloc(ptr, size, 1, GFP_KERNEL);
> > > > +	return ptr;
> > 
> > You may get an object from kzalloc() here, I don't think you want to
> > track that (again), right?
> 
> You are write, I missed the alloc_arch_preferred_bootmem() function
> which may call kzalloc().
> 
> > Pekka already worked out all the central places to catch 'slab already
> > available' allocations, they can probably help you place the hooks.
> 
> It seems that alloc_bootmem_core() is central to all the bootmem
> allocations. Is it OK to place the kmemleak_alloc hook only in this
> function?

I think so. Johannes?

> 
> diff --git a/mm/bootmem.c b/mm/bootmem.c
> index 5a649a0..74cbb34 100644
> --- a/mm/bootmem.c
> +++ b/mm/bootmem.c
> @@ -520,6 +520,7 @@ find_block:
>  		region = phys_to_virt(PFN_PHYS(bdata->node_min_pfn) +
>  				start_off);
>  		memset(region, 0, size);
> +		kmemleak_alloc(region, size, 1, 0);
>  		return region;
>  	}


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