[PATCH 08/32] kasan: introduce kasan_init_object_meta

From: andrey . konovalov
Date: Mon Jun 13 2022 - 16:59:32 EST


From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>

Add a kasan_init_object_meta() helper that initializes metadata for a slab
object and use it in the common code.

For now, the implementations of this helper are the same for the Generic
and tag-based modes, but they will diverge later in the series.

This change hides references to alloc_meta from the common code. This is
desired as only the Generic mode will be using per-object metadata after
this series.

Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
---
mm/kasan/common.c | 10 +++-------
mm/kasan/generic.c | 9 +++++++++
mm/kasan/kasan.h | 2 ++
mm/kasan/tags.c | 9 +++++++++
4 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 2848c7a2402a..f0ee1c1b4b3c 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -312,13 +312,9 @@ static inline u8 assign_tag(struct kmem_cache *cache,
void * __must_check __kasan_init_slab_obj(struct kmem_cache *cache,
const void *object)
{
- struct kasan_alloc_meta *alloc_meta;
-
- if (kasan_stack_collection_enabled()) {
- alloc_meta = kasan_get_alloc_meta(cache, object);
- if (alloc_meta)
- __memset(alloc_meta, 0, sizeof(*alloc_meta));
- }
+ /* Initialize per-object metadata if it is present. */
+ if (kasan_stack_collection_enabled())
+ kasan_init_object_meta(cache, object);

/* Tag is ignored in set_tag() without CONFIG_KASAN_SW/HW_TAGS */
object = set_tag(object, assign_tag(cache, object, true));
diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
index f212b9ae57b5..5462ddbc21e6 100644
--- a/mm/kasan/generic.c
+++ b/mm/kasan/generic.c
@@ -328,6 +328,15 @@ DEFINE_ASAN_SET_SHADOW(f3);
DEFINE_ASAN_SET_SHADOW(f5);
DEFINE_ASAN_SET_SHADOW(f8);

+void kasan_init_object_meta(struct kmem_cache *cache, const void *object)
+{
+ struct kasan_alloc_meta *alloc_meta;
+
+ alloc_meta = kasan_get_alloc_meta(cache, object);
+ if (alloc_meta)
+ __memset(alloc_meta, 0, sizeof(*alloc_meta));
+}
+
static void __kasan_record_aux_stack(void *addr, bool can_alloc)
{
struct slab *slab = kasan_addr_to_slab(addr);
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 4005da62a1e1..751c3b17749a 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -278,6 +278,8 @@ void kasan_report_invalid_free(void *object, unsigned long ip);
struct page *kasan_addr_to_page(const void *addr);
struct slab *kasan_addr_to_slab(const void *addr);

+void kasan_init_object_meta(struct kmem_cache *cache, const void *object);
+
depot_stack_handle_t kasan_save_stack(gfp_t flags, bool can_alloc);
void kasan_set_track(struct kasan_track *track, gfp_t flags);
void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags);
diff --git a/mm/kasan/tags.c b/mm/kasan/tags.c
index 7b1fc8e7c99c..2e200969a4b8 100644
--- a/mm/kasan/tags.c
+++ b/mm/kasan/tags.c
@@ -17,6 +17,15 @@

#include "kasan.h"

+void kasan_init_object_meta(struct kmem_cache *cache, const void *object)
+{
+ struct kasan_alloc_meta *alloc_meta;
+
+ alloc_meta = kasan_get_alloc_meta(cache, object);
+ if (alloc_meta)
+ __memset(alloc_meta, 0, sizeof(*alloc_meta));
+}
+
void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags)
{
struct kasan_alloc_meta *alloc_meta;
--
2.25.1