From: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Subject: kasan: don't round_up too much For hardware tag-based mode kasan_poison_memory() already rounds up the size. Do the same for software modes and remove round_up() from the common code. Link: https://lkml.kernel.org/r/47b232474f1f89dc072aeda0fa58daa6efade377.1606162397.git.andreyknvl@xxxxxxxxxx Link: https://linux-review.googlesource.com/id/Ib397128fac6eba874008662b4964d65352db4aa4 Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Reviewed-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Reviewed-by: Marco Elver <elver@xxxxxxxxxx> Tested-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> Cc: Alexander Potapenko <glider@xxxxxxxxxx> Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> Cc: Branislav Rankov <Branislav.Rankov@xxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx> Cc: Kevin Brodsky <kevin.brodsky@xxxxxxx> Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx> Cc: Will Deacon <will.deacon@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/kasan/common.c | 8 ++------ mm/kasan/shadow.c | 1 + 2 files changed, 3 insertions(+), 6 deletions(-) --- a/mm/kasan/common.c~kasan-dont-round_up-too-much +++ a/mm/kasan/common.c @@ -213,9 +213,7 @@ void __kasan_unpoison_object_data(struct void __kasan_poison_object_data(struct kmem_cache *cache, void *object) { - poison_range(object, - round_up(cache->object_size, KASAN_GRANULE_SIZE), - KASAN_KMALLOC_REDZONE); + poison_range(object, cache->object_size, KASAN_KMALLOC_REDZONE); } /* @@ -288,7 +286,6 @@ static bool ____kasan_slab_free(struct k { u8 tag; void *tagged_object; - unsigned long rounded_up_size; tag = get_tag(object); tagged_object = object; @@ -309,8 +306,7 @@ static bool ____kasan_slab_free(struct k return true; } - rounded_up_size = round_up(cache->object_size, KASAN_GRANULE_SIZE); - poison_range(object, rounded_up_size, KASAN_KMALLOC_FREE); + poison_range(object, cache->object_size, KASAN_KMALLOC_FREE); if (!kasan_stack_collection_enabled()) return false; --- a/mm/kasan/shadow.c~kasan-dont-round_up-too-much +++ a/mm/kasan/shadow.c @@ -83,6 +83,7 @@ void poison_range(const void *address, s * addresses to this function. */ address = kasan_reset_tag(address); + size = round_up(size, KASAN_GRANULE_SIZE); /* Skip KFENCE memory if called explicitly outside of sl*b. */ if (is_kfence_address(address)) _
