On Tue, Nov 10, 2020 at 11:20PM +0100, Andrey Konovalov wrote: > Currently kasan_unpoison_memory() is used as both an external annotation > and as an internal memory poisoning helper. Rename external annotation to > kasan_unpoison_data() and inline the internal helper for hardware > tag-based mode to avoid undeeded function calls. I don't understand why this needs to be renamed again. The users of kasan_unpoison_memory() outweigh those of kasan_unpoison_slab(), of which there seems to be only 1! So can't we just get rid of kasan_unpoison_slab() and just open-code it in mm/mempool.c:kasan_unpoison_element()? That function is already kasan-prefixed, so we can even place a small comment there (which would also be an improvement over current interface, since kasan_unpoison_slab() is not documented and its existence not quite justified). > 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. > > Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> > 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 53c8e8b12fbc..f1a5042ae4fc 100644 > --- a/include/linux/kasan.h > +++ b/include/linux/kasan.h > @@ -74,14 +74,15 @@ 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); > @@ -106,11 +107,6 @@ 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); > @@ -118,8 +114,6 @@ 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) {} > > @@ -127,6 +121,9 @@ 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) {} > @@ -166,7 +163,6 @@ 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 1c905e4290ab..883898487b3f 100644 > --- a/kernel/fork.c > +++ b/kernel/fork.c > @@ -226,7 +226,7 @@ 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); ... this change would become unnecessary. > /* 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 a266b90636a1..4598c1364f19 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 kasan_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)); > +} > + This function is so simple, I think just open-coding kasan_unpoison_memory(ptr, __ksize(ptr)) wherever required is much simpler, also bearing in mind the changes that are coming to the rest of this series. > 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 0303e49904b4..838b29e44e32 100644 > --- a/mm/kasan/hw_tags.c > +++ b/mm/kasan/hw_tags.c > @@ -30,12 +30,6 @@ void kasan_init_hw_tags(void) > pr_info("KernelAddressSanitizer initialized\n"); > } > > -void kasan_unpoison_memory(const void *address, size_t size) > -{ > - hw_set_mem_tag_range(kasan_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 ab7314418604..2d3c99125996 100644 > --- a/mm/kasan/kasan.h > +++ b/mm/kasan/kasan.h > @@ -283,6 +283,12 @@ 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) > +{ > + hw_set_mem_tag_range(kasan_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); > @@ -295,6 +301,7 @@ 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); ... this change would become unnecessary. Thanks, -- Marco
