Re: [PATCH 2/2] slub: Fix kmem_ptr_validate() for non-kernelpointers

[David Rientjes]

On Wed, 7 Apr 2010, Pekka Enberg wrote:

> As suggested by Linus, fix up kmem_ptr_validate() to handle non-kernel pointers
> more graciously. The patch changes kmem_ptr_validate() to use the newly
> introduced kern_ptr_validate() helper to check that a pointer is a valid kernel
> pointer before we attempt to convert it into a 'struct page'.
> 
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
> Cc: David Rientjes <rientjes@xxxxxxxxxx>

Acked-by: David Rientjes <rientjes@xxxxxxxxxx>

> Cc: Ingo Molnar <mingo@xxxxxxx>
> Cc: Matt Mackall <mpm@xxxxxxxxxxx>
> Cc: Nick Piggin <npiggin@xxxxxxx>
> Signed-off-by: Pekka Enberg <penberg@xxxxxxxxxxxxxx>
> ---
>  mm/slub.c |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
> 
> diff --git a/mm/slub.c b/mm/slub.c
> index b364844..7d6c8b1 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -2386,6 +2386,9 @@ int kmem_ptr_validate(struct kmem_cache *s, const void *object)
>  {
>  	struct page *page;
>  
> +	if (!kern_ptr_validate(object, s->size))
> +		return 0;
> +
>  	page = get_object_page(object);
>  
>  	if (!page || s != page->slab)
--
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