The patch titled
Subject: kasan, slub: move kasan_poison_slab hook before page_address
has been added to the -mm tree. Its filename is
kasan-slub-move-kasan_poison_slab-hook-before-page_address.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/kasan-slub-move-kasan_poison_slab-hook-before-page_address.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/kasan-slub-move-kasan_poison_slab-hook-before-page_address.patch
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------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: kasan, slub: move kasan_poison_slab hook before page_address
With tag based KASAN page_address() looks at the page flags to see whether
the resulting pointer needs to have a tag set. Since we don't want to set
a tag when page_address() is called on SLAB pages, we call
page_kasan_tag_reset() in kasan_poison_slab(). However in allocate_slab()
page_address() is called before kasan_poison_slab(). Fix it by changing
the order.
Link: http://lkml.kernel.org/r/cd895d627465a3f1c712647072d17f10883be2a1.1549921721.git.andreyknvl@xxxxxxxxxx
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Evgeniy Stepanov <eugenis@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Kostya Serebryany <kcc@xxxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: Qian Cai <cai@xxxxxx>
Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/mm/slub.c~kasan-slub-move-kasan_poison_slab-hook-before-page_address
+++ a/mm/slub.c
@@ -1642,12 +1642,15 @@ static struct page *allocate_slab(struct
if (page_is_pfmemalloc(page))
SetPageSlabPfmemalloc(page);
+ kasan_poison_slab(page);
+
start = page_address(page);
- if (unlikely(s->flags & SLAB_POISON))
+ if (unlikely(s->flags & SLAB_POISON)) {
+ metadata_access_enable();
memset(start, POISON_INUSE, PAGE_SIZE << order);
-
- kasan_poison_slab(page);
+ metadata_access_disable();
+ }
shuffle = shuffle_freelist(s, page);
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
kasan-fix-assigning-tags-twice.patch
kasan-kmemleak-pass-tagged-pointers-to-kmemleak.patch
kmemleak-account-for-tagged-pointers-when-calculating-pointer-range.patch
kasan-slub-move-kasan_poison_slab-hook-before-page_address.patch
kasan-slub-fix-conflicts-with-config_slab_freelist_hardened.patch
