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Message-ID: <CACT4Y+bJxJ+EeStyytnnRyjRwoZNPGJ9ws20GfoCBFGWvUSBPg@mail.gmail.com>
Date: Wed, 28 Oct 2020 12:36:36 +0100
From: Dmitry Vyukov <dvyukov@...gle.com>
To: Andrey Konovalov <andreyknvl@...gle.com>
Cc: Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>,
Vincenzo Frascino <vincenzo.frascino@....com>,
Alexander Potapenko <glider@...gle.com>,
Marco Elver <elver@...gle.com>,
Evgenii Stepanov <eugenis@...gle.com>,
Kostya Serebryany <kcc@...gle.com>,
Peter Collingbourne <pcc@...gle.com>,
Serban Constantinescu <serbanc@...gle.com>,
Andrey Ryabinin <aryabinin@...tuozzo.com>,
Elena Petrova <lenaptr@...gle.com>,
Branislav Rankov <Branislav.Rankov@....com>,
Kevin Brodsky <kevin.brodsky@....com>,
Andrew Morton <akpm@...ux-foundation.org>,
kasan-dev <kasan-dev@...glegroups.com>,
Linux ARM <linux-arm-kernel@...ts.infradead.org>,
Linux-MM <linux-mm@...ck.org>,
LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH RFC v2 12/21] kasan: inline and rename kasan_unpoison_memory
On Thu, Oct 22, 2020 at 3:19 PM Andrey Konovalov <andreyknvl@...gle.com> wrote:
>
> Currently kasan_unpoison_memory() is used as both an external annotation
> and as internal memory poisoning helper. Rename external annotation to
> kasan_unpoison_data() and inline the internal helper for for hardware
> tag-based mode to avoid undeeded function calls.
>
> There's the external annotation kasan_unpoison_slab() that is currently
> defined as static inline and uses kasan_unpoison_memory(). With this
> change it's turned into a function call. Overall, this results in the
> same number of calls for hardware tag-based mode as
> kasan_unpoison_memory() is now inlined.
Can't we leave kasan_unpoison_slab as is? Or there are other reasons
to uninline it?
It seems that uninling it is orthogonal to the rest of this patch.
> Signed-off-by: Andrey Konovalov <andreyknvl@...gle.com>
> Link: https://linux-review.googlesource.com/id/Ia7c8b659f79209935cbaab3913bf7f082cc43a0e
> ---
> include/linux/kasan.h | 16 ++++++----------
> kernel/fork.c | 2 +-
> mm/kasan/common.c | 10 ++++++++++
> mm/kasan/hw_tags.c | 6 ------
> mm/kasan/kasan.h | 7 +++++++
> mm/slab_common.c | 2 +-
> 6 files changed, 25 insertions(+), 18 deletions(-)
>
> diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> index 6377d7d3a951..2b9023224474 100644
> --- a/include/linux/kasan.h
> +++ b/include/linux/kasan.h
> @@ -66,14 +66,15 @@ static inline void kasan_disable_current(void) {}
>
> #ifdef CONFIG_KASAN
>
> -void kasan_unpoison_memory(const void *address, size_t size);
> -
> void kasan_alloc_pages(struct page *page, unsigned int order);
> void kasan_free_pages(struct page *page, unsigned int order);
>
> void kasan_cache_create(struct kmem_cache *cache, unsigned int *size,
> slab_flags_t *flags);
>
> +void kasan_unpoison_data(const void *address, size_t size);
> +void kasan_unpoison_slab(const void *ptr);
> +
> void kasan_poison_slab(struct page *page);
> void kasan_unpoison_object_data(struct kmem_cache *cache, void *object);
> void kasan_poison_object_data(struct kmem_cache *cache, void *object);
> @@ -98,11 +99,6 @@ struct kasan_cache {
> int free_meta_offset;
> };
>
> -size_t __ksize(const void *);
> -static inline void kasan_unpoison_slab(const void *ptr)
> -{
> - kasan_unpoison_memory(ptr, __ksize(ptr));
> -}
> size_t kasan_metadata_size(struct kmem_cache *cache);
>
> bool kasan_save_enable_multi_shot(void);
> @@ -110,8 +106,6 @@ void kasan_restore_multi_shot(bool enabled);
>
> #else /* CONFIG_KASAN */
>
> -static inline void kasan_unpoison_memory(const void *address, size_t size) {}
> -
> static inline void kasan_alloc_pages(struct page *page, unsigned int order) {}
> static inline void kasan_free_pages(struct page *page, unsigned int order) {}
>
> @@ -119,6 +113,9 @@ static inline void kasan_cache_create(struct kmem_cache *cache,
> unsigned int *size,
> slab_flags_t *flags) {}
>
> +static inline void kasan_unpoison_data(const void *address, size_t size) { }
> +static inline void kasan_unpoison_slab(const void *ptr) { }
> +
> static inline void kasan_poison_slab(struct page *page) {}
> static inline void kasan_unpoison_object_data(struct kmem_cache *cache,
> void *object) {}
> @@ -158,7 +155,6 @@ static inline bool kasan_slab_free(struct kmem_cache *s, void *object,
> return false;
> }
>
> -static inline void kasan_unpoison_slab(const void *ptr) { }
> static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; }
>
> #endif /* CONFIG_KASAN */
> diff --git a/kernel/fork.c b/kernel/fork.c
> index b41fecca59d7..858d78eee6ec 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -225,7 +225,7 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
> continue;
>
> /* Mark stack accessible for KASAN. */
> - kasan_unpoison_memory(s->addr, THREAD_SIZE);
> + kasan_unpoison_data(s->addr, THREAD_SIZE);
>
> /* Clear stale pointers from reused stack. */
> memset(s->addr, 0, THREAD_SIZE);
> diff --git a/mm/kasan/common.c b/mm/kasan/common.c
> index 9008fc6b0810..1a5e6c279a72 100644
> --- a/mm/kasan/common.c
> +++ b/mm/kasan/common.c
> @@ -184,6 +184,16 @@ struct kasan_free_meta *kasan_get_free_meta(struct kmem_cache *cache,
> return (void *)reset_tag(object) + cache->kasan_info.free_meta_offset;
> }
>
> +void kasan_unpoison_data(const void *address, size_t size)
> +{
> + kasan_unpoison_memory(address, size);
> +}
> +
> +void kasan_unpoison_slab(const void *ptr)
> +{
> + kasan_unpoison_memory(ptr, __ksize(ptr));
> +}
> +
> void kasan_poison_slab(struct page *page)
> {
> unsigned long i;
> diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c
> index f03161f3da19..915142da6b57 100644
> --- a/mm/kasan/hw_tags.c
> +++ b/mm/kasan/hw_tags.c
> @@ -24,12 +24,6 @@ void __init kasan_init_tags(void)
> pr_info("KernelAddressSanitizer initialized\n");
> }
>
> -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));
> -}
> -
> 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 8d84ae6f58f1..da08b2533d73 100644
> --- a/mm/kasan/kasan.h
> +++ b/mm/kasan/kasan.h
> @@ -280,6 +280,12 @@ static inline void kasan_poison_memory(const void *address, size_t size, u8 valu
> round_up(size, KASAN_GRANULE_SIZE), value);
> }
>
> +static inline 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));
> +}
> +
> static inline bool check_invalid_free(void *addr)
> {
> u8 ptr_tag = get_tag(addr);
> @@ -292,6 +298,7 @@ static inline bool check_invalid_free(void *addr)
> #else /* CONFIG_KASAN_HW_TAGS */
>
> void kasan_poison_memory(const void *address, size_t size, u8 value);
> +void kasan_unpoison_memory(const void *address, size_t size);
> bool check_invalid_free(void *addr);
>
> #endif /* CONFIG_KASAN_HW_TAGS */
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index 53d0f8bb57ea..f1b0c4a22f08 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -1176,7 +1176,7 @@ size_t ksize(const void *objp)
> * We assume that ksize callers could use whole allocated area,
> * so we need to unpoison this area.
> */
> - kasan_unpoison_memory(objp, size);
> + kasan_unpoison_data(objp, size);
> return size;
> }
> EXPORT_SYMBOL(ksize);
> --
> 2.29.0.rc1.297.gfa9743e501-goog
>
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