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authorAndrey Konovalov <andreyknvl@google.com>2021-02-25 17:20:03 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-26 09:41:02 -0800
commit43a219cbe5a46ec3f6a1874bb2cb2fd4de8322cc (patch)
tree5ce24efc53634e210b053ce74f29ad406224b4eb
parente2db1a9aa3814960a56583df39ea71e36d802278 (diff)
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kasan: optimize large kmalloc poisoning
Similarly to kasan_kmalloc(), kasan_kmalloc_large() doesn't need to unpoison the object as it as already unpoisoned by alloc_pages() (or by ksize() for krealloc()). This patch changes kasan_kmalloc_large() to only poison the redzone. Link: https://lkml.kernel.org/r/33dee5aac0e550ad7f8e26f590c9b02c6129b4a3.1612546384.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>
-rw-r--r--mm/kasan/common.c20
1 files changed, 15 insertions, 5 deletions
diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 218b23a5a597..dcdc92948364 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -494,7 +494,6 @@ EXPORT_SYMBOL(__kasan_kmalloc);
void * __must_check __kasan_kmalloc_large(const void *ptr, size_t size,
gfp_t flags)
{
- struct page *page;
unsigned long redzone_start;
unsigned long redzone_end;
@@ -504,12 +503,23 @@ void * __must_check __kasan_kmalloc_large(const void *ptr, size_t size,
if (unlikely(ptr == NULL))
return NULL;
- page = virt_to_page(ptr);
+ /*
+ * The object has already been unpoisoned by kasan_alloc_pages() for
+ * alloc_pages() or by ksize() for krealloc().
+ */
+
+ /*
+ * The redzone has byte-level precision for the generic mode.
+ * Partially poison the last object granule to cover the unaligned
+ * part of the redzone.
+ */
+ if (IS_ENABLED(CONFIG_KASAN_GENERIC))
+ kasan_poison_last_granule(ptr, size);
+
+ /* Poison the aligned part of the redzone. */
redzone_start = round_up((unsigned long)(ptr + size),
KASAN_GRANULE_SIZE);
- redzone_end = (unsigned long)ptr + page_size(page);
-
- kasan_unpoison(ptr, size);
+ redzone_end = (unsigned long)ptr + page_size(virt_to_page(ptr));
kasan_poison((void *)redzone_start, redzone_end - redzone_start,
KASAN_PAGE_REDZONE);