Re: [RFC PATCH 2/3] kmemleak: Add callbacks to the bootmem allocator

Pekka Enberg
2009-07-08T06:41:51Z

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;
> }