Re: [PATCH v2] kasan, slub: fix handling of kasan_slab_free hook

[Andrey Ryabinin]

On 03/06/2018 09:18 PM, Andrey Konovalov wrote:
> The kasan_slab_free hook's return value denotes whether the reuse of a
> slab object must be delayed (e.g. when the object is put into memory
> qurantine).
> 
> The current way SLUB handles this hook is by ignoring its return value
> and hardcoding checks similar (but not exactly the same) to the ones
> performed in kasan_slab_free, which is prone to making mistakes.
> 
> The main difference between the hardcoded checks and the ones in
> kasan_slab_free is whether we want to perform a free in case when an
> invalid-free or a double-free was detected (we don't).
> 
> This patch changes the way SLUB handles this by:
> 1. taking into account the return value of kasan_slab_free for each of
>    the objects, that are being freed;
> 2. reconstructing the freelist of objects to exclude the ones, whose
>    reuse must be delayed.
> 
> Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
> ---

Acked-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>