Re: [PATCH v2 1/2] mm, kasan: don't call kasan_krealloc() from ksize().

From: Andrey Ryabinin
Date: Fri Apr 15 2016 - 12:14:30 EST




On 04/13/2016 02:20 PM, Alexander Potapenko wrote:
> Instead of calling kasan_krealloc(), which replaces the memory allocation
> stack ID (if stack depot is used), just unpoison the whole memory chunk.
>
> Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx>

Acked-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>

> ---
> v2: - splitted v1 into two patches
> ---
> mm/slab.c | 2 +-
> mm/slub.c | 5 +++--
> 2 files changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/mm/slab.c b/mm/slab.c
> index 17e2848..de46319 100644
> --- a/mm/slab.c
> +++ b/mm/slab.c
> @@ -4324,7 +4324,7 @@ size_t ksize(const void *objp)
> /* We assume that ksize callers could use the whole allocated area,
> * so we need to unpoison this area.
> */
> - kasan_krealloc(objp, size, GFP_NOWAIT);
> + kasan_unpoison_shadow(objp, size);
>
> return size;
> }
> diff --git a/mm/slub.c b/mm/slub.c
> index 4dbb109e..62194e2 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -3635,8 +3635,9 @@ size_t ksize(const void *object)
> {
> size_t size = __ksize(object);
> /* We assume that ksize callers could use whole allocated area,
> - so we need unpoison this area. */
> - kasan_krealloc(object, size, GFP_NOWAIT);
> + * so we need to unpoison this area.
> + */
> + kasan_unpoison_shadow(object, size);
> return size;
> }
> EXPORT_SYMBOL(ksize);
>