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| author | Andrey Konovalov <andreyknvl@google.com> | 2021-02-26 04:19:59 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-02-26 20:41:02 +0300 |
| commit | e2db1a9aa3814960a56583df39ea71e36d802278 (patch) | |
| tree | b4918793cf7ad4f5ba30e83f6802861f6b367d11 /mm/slub.c | |
| parent | 928501344fc645f80390afc12708c81b3595745d (diff) | |
| download | linux-e2db1a9aa3814960a56583df39ea71e36d802278.tar.xz | |
kasan, mm: optimize kmalloc poisoning
For allocations from kmalloc caches, kasan_kmalloc() always follows
kasan_slab_alloc(). Currenly, both of them unpoison the whole object,
which is unnecessary.
This patch provides separate implementations for both annotations:
kasan_slab_alloc() unpoisons the whole object, and kasan_kmalloc() only
poisons the redzone.
For generic KASAN, the redzone start might not be aligned to
KASAN_GRANULE_SIZE. Therefore, the poisoning is split in two parts:
kasan_poison_last_granule() poisons the unaligned part, and then
kasan_poison() poisons the rest.
This patch also clarifies alignment guarantees of each of the poisoning
functions and drops the unnecessary round_up() call for redzone_end.
With this change, the early SLUB cache annotation needs to be changed to
kasan_slab_alloc(), as kasan_kmalloc() doesn't unpoison objects now. The
number of poisoned bytes for objects in this cache stays the same, as
kmem_cache_node->object_size is equal to sizeof(struct kmem_cache_node).
Link: https://lkml.kernel.org/r/7e3961cb52be380bc412860332063f5f7ce10d13.1612546384.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/slub.c')
| -rw-r--r-- | mm/slub.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/mm/slub.c b/mm/slub.c index 383616af28c4..e26c274b4657 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -3579,8 +3579,7 @@ static void early_kmem_cache_node_alloc(int node) init_object(kmem_cache_node, n, SLUB_RED_ACTIVE); init_tracking(kmem_cache_node, n); #endif - n = kasan_kmalloc(kmem_cache_node, n, sizeof(struct kmem_cache_node), - GFP_KERNEL); + n = kasan_slab_alloc(kmem_cache_node, n, GFP_KERNEL); page->freelist = get_freepointer(kmem_cache_node, n); page->inuse = 1; page->frozen = 0; |