linux-kernel - [PATCH AUTOSEL 4.9 12/24] kasan, slub: move kasan_poison_slab hook before page

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Date:   Wed, 13 Mar 2019 15:16:35 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Andrey Konovalov <andreyknvl@...gle.com>,
        Alexander Potapenko <glider@...gle.com>,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Catalin Marinas <catalin.marinas@....com>,
        Christoph Lameter <cl@...ux.com>,
        David Rientjes <rientjes@...gle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Evgeniy Stepanov <eugenis@...gle.com>,
        Joonsoo Kim <iamjoonsoo.kim@....com>,
        Kostya Serebryany <kcc@...gle.com>,
        Pekka Enberg <penberg@...nel.org>, Qian Cai <cai@....pw>,
        Vincenzo Frascino <vincenzo.frascino@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Sasha Levin <sashal@...nel.org>, linux-mm@...ck.org
Subject: [PATCH AUTOSEL 4.9 12/24] kasan, slub: move kasan_poison_slab hook before page_address

From: Andrey Konovalov <andreyknvl@...gle.com>

[ Upstream commit a71012242837fe5e67d8c999cfc357174ed5dba0 ]

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.

[andreyknvl@...gle.com: fix compilation error when CONFIG_SLUB_DEBUG=n]
  Link: http://lkml.kernel.org/r/ac27cc0bbaeb414ed77bcd6671a877cf3546d56e.1550066133.git.andreyknvl@google.com
Link: http://lkml.kernel.org/r/cd895d627465a3f1c712647072d17f10883be2a1.1549921721.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@...gle.com>
Cc: Alexander Potapenko <glider@...gle.com>
Cc: Andrey Ryabinin <aryabinin@...tuozzo.com>
Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Christoph Lameter <cl@...ux.com>
Cc: David Rientjes <rientjes@...gle.com>
Cc: Dmitry Vyukov <dvyukov@...gle.com>
Cc: Evgeniy Stepanov <eugenis@...gle.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@....com>
Cc: Kostya Serebryany <kcc@...gle.com>
Cc: Pekka Enberg <penberg@...nel.org>
Cc: Qian Cai <cai@....pw>
Cc: Vincenzo Frascino <vincenzo.frascino@....com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 mm/slub.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 131dee87a67c..979400b1a781 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1052,6 +1052,16 @@ static void setup_object_debug(struct kmem_cache *s, struct page *page,
 	init_tracking(s, object);
 }
 
+static void setup_page_debug(struct kmem_cache *s, void *addr, int order)
+{
+	if (!(s->flags & SLAB_POISON))
+		return;
+
+	metadata_access_enable();
+	memset(addr, POISON_INUSE, PAGE_SIZE << order);
+	metadata_access_disable();
+}
+
 static inline int alloc_consistency_checks(struct kmem_cache *s,
 					struct page *page,
 					void *object, unsigned long addr)
@@ -1269,6 +1279,8 @@ unsigned long kmem_cache_flags(unsigned long object_size,
 #else /* !CONFIG_SLUB_DEBUG */
 static inline void setup_object_debug(struct kmem_cache *s,
 			struct page *page, void *object) {}
+static inline void setup_page_debug(struct kmem_cache *s,
+			void *addr, int order) {}
 
 static inline int alloc_debug_processing(struct kmem_cache *s,
 	struct page *page, void *object, unsigned long addr) { return 0; }
@@ -1584,12 +1596,11 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 	if (page_is_pfmemalloc(page))
 		SetPageSlabPfmemalloc(page);
 
-	start = page_address(page);
+	kasan_poison_slab(page);
 
-	if (unlikely(s->flags & SLAB_POISON))
-		memset(start, POISON_INUSE, PAGE_SIZE << order);
+	start = page_address(page);
 
-	kasan_poison_slab(page);
+	setup_page_debug(s, start, order);
 
 	shuffle = shuffle_freelist(s, page);
 
-- 
2.19.1