Re: [PATCH RFC v2 11/21] kasan: inline kasan_poison_memory and check_invalid_free

[Dmitry Vyukov]

On Thu, Oct 22, 2020 at 3:19 PM 'Andrey Konovalov' via kasan-dev
<kasan-dev@xxxxxxxxxxxxxxxx> wrote:
>
> Using kasan_poison_memory() or check_invalid_free() currently results in
> function calls. Move their definitions to mm/kasan/kasan.h and turn them
> into static inline functions for hardware tag-based mode to avoid uneeded
> function calls.
>
> Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
> Link: https://linux-review.googlesource.com/id/Ia9d8191024a12d1374675b3d27197f10193f50bb

Reviewed-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>

> ---
>  mm/kasan/hw_tags.c | 15 ---------------
>  mm/kasan/kasan.h   | 28 ++++++++++++++++++++++++----
>  2 files changed, 24 insertions(+), 19 deletions(-)
>
> diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c
> index 4c24bfcfeff9..f03161f3da19 100644
> --- a/mm/kasan/hw_tags.c
> +++ b/mm/kasan/hw_tags.c
> @@ -24,27 +24,12 @@ void __init kasan_init_tags(void)
>         pr_info("KernelAddressSanitizer initialized\n");
>  }
>
> -void kasan_poison_memory(const void *address, size_t size, u8 value)
> -{
> -       set_mem_tag_range(reset_tag(address),
> -                         round_up(size, KASAN_GRANULE_SIZE), value);
> -}
> -
>  void kasan_unpoison_memory(const void *address, size_t size)
>  {
>         set_mem_tag_range(reset_tag(address),
>                           round_up(size, KASAN_GRANULE_SIZE), get_tag(address));
>  }
>
> -bool check_invalid_free(void *addr)
> -{
> -       u8 ptr_tag = get_tag(addr);
> -       u8 mem_tag = get_mem_tag(addr);
> -
> -       return (mem_tag == KASAN_TAG_INVALID) ||
> -               (ptr_tag != KASAN_TAG_KERNEL && ptr_tag != mem_tag);
> -}
> -
>  void kasan_set_free_info(struct kmem_cache *cache,
>                                 void *object, u8 tag)
>  {
> diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> index 94ba15c2f860..8d84ae6f58f1 100644
> --- a/mm/kasan/kasan.h
> +++ b/mm/kasan/kasan.h
> @@ -153,8 +153,6 @@ struct kasan_alloc_meta *kasan_get_alloc_meta(struct kmem_cache *cache,
>  struct kasan_free_meta *kasan_get_free_meta(struct kmem_cache *cache,
>                                                 const void *object);
>
> -void kasan_poison_memory(const void *address, size_t size, u8 value);
> -
>  #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
>
>  static inline const void *kasan_shadow_to_mem(const void *shadow_addr)
> @@ -194,8 +192,6 @@ void print_tags(u8 addr_tag, const void *addr);
>  static inline void print_tags(u8 addr_tag, const void *addr) { }
>  #endif
>
> -bool check_invalid_free(void *addr);
> -
>  void *find_first_bad_addr(void *addr, size_t size);
>  const char *get_bug_type(struct kasan_access_info *info);
>  void metadata_fetch_row(char *buffer, void *row);
> @@ -276,6 +272,30 @@ static inline u8 random_tag(void)
>  }
>  #endif
>
> +#ifdef CONFIG_KASAN_HW_TAGS
> +
> +static inline void kasan_poison_memory(const void *address, size_t size, u8 value)
> +{
> +       set_mem_tag_range(reset_tag(address),
> +                         round_up(size, KASAN_GRANULE_SIZE), value);
> +}
> +
> +static inline bool check_invalid_free(void *addr)
> +{
> +       u8 ptr_tag = get_tag(addr);
> +       u8 mem_tag = get_mem_tag(addr);
> +
> +       return (mem_tag == KASAN_TAG_INVALID) ||
> +               (ptr_tag != KASAN_TAG_KERNEL && ptr_tag != mem_tag);
> +}
> +
> +#else /* CONFIG_KASAN_HW_TAGS */
> +
> +void kasan_poison_memory(const void *address, size_t size, u8 value);
> +bool check_invalid_free(void *addr);
> +
> +#endif /* CONFIG_KASAN_HW_TAGS */
> +
>  /*
>   * Exported functions for interfaces called from assembly or from generated
>   * code. Declarations here to avoid warning about missing declarations.
> --
> 2.29.0.rc1.297.gfa9743e501-goog
>
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