kasan, kmemleak: pass tagged pointers to kmemleak

Right now we call kmemleak hooks before assigning tags to pointers in
KASAN hooks.  As a result, when an objects gets allocated, kmemleak sees a
differently tagged pointer, compared to the one it sees when the object
gets freed.  Fix it by calling KASAN hooks before kmemleak's ones.

Link: http://lkml.kernel.org/r/cd825aa4897b0fc37d3316838993881daccbe9f5.1549921721.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reported-by: Qian Cai <cai@lca.pw>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgeniy Stepanov <eugenis@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/slab.h b/mm/slab.h
index 4190c24..638ea1b 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -437,11 +437,9 @@
 
 	flags &= gfp_allowed_mask;
 	for (i = 0; i < size; i++) {
-		void *object = p[i];
-
-		kmemleak_alloc_recursive(object, s->object_size, 1,
+		p[i] = kasan_slab_alloc(s, p[i], flags);
+		kmemleak_alloc_recursive(p[i], s->object_size, 1,
 					 s->flags, flags);
-		p[i] = kasan_slab_alloc(s, object, flags);
 	}
 
 	if (memcg_kmem_enabled())