On Fri, 29 Jan 2021 at 19:50, Andrey Konovalov <andreyknvl@xxxxxxxxxx> wrote:
>
> KFENCE annotations operate on untagged addresses.
>
> Untag addresses in KASAN runtime where they might be tagged.
>
> Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Reviewed-by: Marco Elver <elver@xxxxxxxxxx>
Thank you!
> ---
>
> This can be squashed into:
>
> revert kasan-remove-kfence-leftovers
> kfence, kasan: make KFENCE compatible with KASA
>
> ---
> mm/kasan/common.c | 2 +-
> mm/kasan/kasan.h | 12 +++++++++---
> 2 files changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/mm/kasan/common.c b/mm/kasan/common.c
> index a390fae9d64b..fe852f3cfa42 100644
> --- a/mm/kasan/common.c
> +++ b/mm/kasan/common.c
> @@ -416,7 +416,7 @@ static void *____kasan_kmalloc(struct kmem_cache *cache, const void *object,
> if (unlikely(object == NULL))
> return NULL;
>
> - if (is_kfence_address(object))
> + if (is_kfence_address(kasan_reset_tag(object)))
> return (void *)object;
>
> redzone_start = round_up((unsigned long)(object + size),
> diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> index 11c6e3650468..4fb8106f8e31 100644
> --- a/mm/kasan/kasan.h
> +++ b/mm/kasan/kasan.h
> @@ -320,22 +320,28 @@ static inline u8 kasan_random_tag(void) { return 0; }
>
> static inline void kasan_poison(const void *address, size_t size, u8 value)
> {
> + address = kasan_reset_tag(address);
> +
> /* Skip KFENCE memory if called explicitly outside of sl*b. */
> if (is_kfence_address(address))
> return;
>
> - hw_set_mem_tag_range(kasan_reset_tag(address),
> + hw_set_mem_tag_range((void *)address,
> round_up(size, KASAN_GRANULE_SIZE), value);
> }
>
> static inline void kasan_unpoison(const void *address, size_t size)
> {
> + u8 tag = get_tag(address);
> +
> + address = kasan_reset_tag(address);
> +
> /* Skip KFENCE memory if called explicitly outside of sl*b. */
> if (is_kfence_address(address))
> return;
>
> - hw_set_mem_tag_range(kasan_reset_tag(address),
> - round_up(size, KASAN_GRANULE_SIZE), get_tag(address));
> + hw_set_mem_tag_range((void *)address,
> + round_up(size, KASAN_GRANULE_SIZE), tag);
> }
>
> static inline bool kasan_byte_accessible(const void *addr)
> --
> 2.30.0.365.g02bc693789-goog
>
