From: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Subject: kasan: simplify assign_tag and set_tag calls set_tag() already ignores the tag for the generic mode, so just call it as is. Add a check for the generic mode to assign_tag(), and simplify its call in ____kasan_kmalloc(). Link: https://lkml.kernel.org/r/121eeab245f98555862b289d2ba9269c868fbbcf.1606162397.git.andreyknvl@xxxxxxxxxx Link: https://linux-review.googlesource.com/id/I18905ca78fb4a3d60e1a34a4ca00247272480438 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 | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) --- a/mm/kasan/common.c~kasan-simplify-assign_tag-and-set_tag-calls +++ a/mm/kasan/common.c @@ -233,6 +233,9 @@ void __kasan_poison_object_data(struct k static u8 assign_tag(struct kmem_cache *cache, const void *object, bool init, bool keep_tag) { + if (IS_ENABLED(CONFIG_KASAN_GENERIC)) + return 0xff; + /* * 1. When an object is kmalloc()'ed, two hooks are called: * kasan_slab_alloc() and kasan_kmalloc(). We assign the @@ -275,8 +278,8 @@ void * __must_check __kasan_init_slab_ob __memset(alloc_meta, 0, sizeof(*alloc_meta)); } - if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) || IS_ENABLED(CONFIG_KASAN_HW_TAGS)) - object = set_tag(object, assign_tag(cache, object, true, false)); + /* Tag is ignored in set_tag() without CONFIG_KASAN_SW/HW_TAGS */ + object = set_tag(object, assign_tag(cache, object, true, false)); return (void *)object; } @@ -360,7 +363,7 @@ static void *____kasan_kmalloc(struct km { unsigned long redzone_start; unsigned long redzone_end; - u8 tag = 0xff; + u8 tag; if (gfpflags_allow_blocking(flags)) quarantine_reduce(); @@ -372,9 +375,7 @@ static void *____kasan_kmalloc(struct km KASAN_GRANULE_SIZE); redzone_end = round_up((unsigned long)object + cache->object_size, KASAN_GRANULE_SIZE); - - if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) || IS_ENABLED(CONFIG_KASAN_HW_TAGS)) - tag = assign_tag(cache, object, false, keep_tag); + tag = assign_tag(cache, object, false, keep_tag); /* Tag is ignored in set_tag without CONFIG_KASAN_SW/HW_TAGS */ unpoison_range(set_tag(object, tag), size); _
