queue-4.14/kasan-slub-move-kasan_poison_slab-hook-before-page_a.patch

   1 From a8146d43007331bebbe675fd3acbcd6a46342a37 Mon Sep 17 00:00:00 2001
   2 From: Andrey Konovalov <andreyknvl@google.com>
   3 Date: Wed, 20 Feb 2019 22:19:23 -0800
   4 Subject: kasan, slub: move kasan_poison_slab hook before page_address
   5
   6 [ Upstream commit a71012242837fe5e67d8c999cfc357174ed5dba0 ]
   7
   8 With tag based KASAN page_address() looks at the page flags to see whether
   9 the resulting pointer needs to have a tag set.  Since we don't want to set
  10 a tag when page_address() is called on SLAB pages, we call
  11 page_kasan_tag_reset() in kasan_poison_slab().  However in allocate_slab()
  12 page_address() is called before kasan_poison_slab().  Fix it by changing
  13 the order.
  14
  15 [andreyknvl@google.com: fix compilation error when CONFIG_SLUB_DEBUG=n]
  16   Link: http://lkml.kernel.org/r/ac27cc0bbaeb414ed77bcd6671a877cf3546d56e.1550066133.git.andreyknvl@google.com
  17 Link: http://lkml.kernel.org/r/cd895d627465a3f1c712647072d17f10883be2a1.1549921721.git.andreyknvl@google.com
  18 Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
  19 Cc: Alexander Potapenko <glider@google.com>
  20 Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
  21 Cc: Catalin Marinas <catalin.marinas@arm.com>
  22 Cc: Christoph Lameter <cl@linux.com>
  23 Cc: David Rientjes <rientjes@google.com>
  24 Cc: Dmitry Vyukov <dvyukov@google.com>
  25 Cc: Evgeniy Stepanov <eugenis@google.com>
  26 Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
  27 Cc: Kostya Serebryany <kcc@google.com>
  28 Cc: Pekka Enberg <penberg@kernel.org>
  29 Cc: Qian Cai <cai@lca.pw>
  30 Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
  31 Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
  32 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
  33 Signed-off-by: Sasha Levin <sashal@kernel.org>
  34 ---
  35  mm/slub.c | 19 +++++++++++++++----
  36  1 file changed, 15 insertions(+), 4 deletions(-)
  37
  38 diff --git a/mm/slub.c b/mm/slub.c
  39 index 220d42e592ef..f14ef59c9e57 100644
  40 --- a/mm/slub.c
  41 +++ b/mm/slub.c
  42 @@ -1087,6 +1087,16 @@ static void setup_object_debug(struct kmem_cache *s, struct page *page,
  43         init_tracking(s, object);
  44  }
  45
  46 +static void setup_page_debug(struct kmem_cache *s, void *addr, int order)
  47 +{
  48 +       if (!(s->flags & SLAB_POISON))
  49 +               return;
  50 +
  51 +       metadata_access_enable();
  52 +       memset(addr, POISON_INUSE, PAGE_SIZE << order);
  53 +       metadata_access_disable();
  54 +}
  55 +
  56  static inline int alloc_consistency_checks(struct kmem_cache *s,
  57                                         struct page *page,
  58                                         void *object, unsigned long addr)
  59 @@ -1304,6 +1314,8 @@ unsigned long kmem_cache_flags(unsigned long object_size,
  60  #else /* !CONFIG_SLUB_DEBUG */
  61  static inline void setup_object_debug(struct kmem_cache *s,
  62                         struct page *page, void *object) {}
  63 +static inline void setup_page_debug(struct kmem_cache *s,
  64 +                       void *addr, int order) {}
  65
  66  static inline int alloc_debug_processing(struct kmem_cache *s,
  67         struct page *page, void *object, unsigned long addr) { return 0; }
  68 @@ -1599,12 +1611,11 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
  69         if (page_is_pfmemalloc(page))
  70                 SetPageSlabPfmemalloc(page);
  71
  72 -       start = page_address(page);
  73 +       kasan_poison_slab(page);
  74
  75 -       if (unlikely(s->flags & SLAB_POISON))
  76 -               memset(start, POISON_INUSE, PAGE_SIZE << order);
  77 +       start = page_address(page);
  78
  79 -       kasan_poison_slab(page);
  80 +       setup_page_debug(s, start, order);
  81
  82         shuffle = shuffle_freelist(s, page);
  83
  84 --
  85 2.19.1
  86