Re: [PATCH 19/32] kasan: pass tagged pointers to kasan_save_alloc/free_info

From: Marco Elver
Date: Mon Jun 20 2022 - 05:54:34 EST


On Mon, Jun 13, 2022 at 10:14PM +0200, andrey.konovalov@xxxxxxxxx wrote:
> From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
>
> Pass tagged pointers to kasan_save_alloc/free_info().
>
> This is a preparatory patch to simplify other changes in the series.
>
> Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
> ---
> mm/kasan/common.c | 4 ++--
> mm/kasan/generic.c | 3 +--
> mm/kasan/kasan.h | 2 +-
> mm/kasan/tags.c | 3 +--
> 4 files changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/mm/kasan/common.c b/mm/kasan/common.c
> index f937b6c9e86a..519fd0b3040b 100644
> --- a/mm/kasan/common.c
> +++ b/mm/kasan/common.c
> @@ -227,7 +227,7 @@ static inline bool ____kasan_slab_free(struct kmem_cache *cache, void *object,
> return false;
>
> if (kasan_stack_collection_enabled())
> - kasan_save_free_info(cache, object, tag);
> + kasan_save_free_info(cache, tagged_object);
>

Variable 'tag' becomes unused in this function after this patch.

> return kasan_quarantine_put(cache, object);
> }
> @@ -316,7 +316,7 @@ void * __must_check __kasan_slab_alloc(struct kmem_cache *cache,
>
> /* Save alloc info (if possible) for non-kmalloc() allocations. */
> if (kasan_stack_collection_enabled() && !cache->kasan_info.is_kmalloc)
> - kasan_save_alloc_info(cache, (void *)object, flags);
> + kasan_save_alloc_info(cache, tagged_object, flags);
>
> return tagged_object;
> }
> diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
> index f6bef347de87..aff39af3c532 100644
> --- a/mm/kasan/generic.c
> +++ b/mm/kasan/generic.c
> @@ -500,8 +500,7 @@ void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags)
> kasan_set_track(&alloc_meta->alloc_track, flags);
> }
>
> -void kasan_save_free_info(struct kmem_cache *cache,
> - void *object, u8 tag)
> +void kasan_save_free_info(struct kmem_cache *cache, void *object)
> {
> struct kasan_free_meta *free_meta;
>
> diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> index 30ec9ebf52c3..e8329935fbfb 100644
> --- a/mm/kasan/kasan.h
> +++ b/mm/kasan/kasan.h
> @@ -308,7 +308,7 @@ static inline void kasan_init_object_meta(struct kmem_cache *cache, const void *
> depot_stack_handle_t kasan_save_stack(gfp_t flags, bool can_alloc);
> void kasan_set_track(struct kasan_track *track, gfp_t flags);
> void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags);
> -void kasan_save_free_info(struct kmem_cache *cache, void *object, u8 tag);
> +void kasan_save_free_info(struct kmem_cache *cache, void *object);
> struct kasan_track *kasan_get_alloc_track(struct kmem_cache *cache,
> void *object);
> struct kasan_track *kasan_get_free_track(struct kmem_cache *cache,
> diff --git a/mm/kasan/tags.c b/mm/kasan/tags.c
> index 4f24669085e9..fd11d10a4ffc 100644
> --- a/mm/kasan/tags.c
> +++ b/mm/kasan/tags.c
> @@ -21,8 +21,7 @@ void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags)
> {
> }
>
> -void kasan_save_free_info(struct kmem_cache *cache,
> - void *object, u8 tag)
> +void kasan_save_free_info(struct kmem_cache *cache, void *object)
> {
> }
>
> --
> 2.25.1
>
> --
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