The patch titled
Subject: kasan: only define kasan_cache_create for Generic mode
has been added to the -mm mm-unstable branch. Its filename is
kasan-only-define-kasan_cache_create-for-generic-mode.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kasan-only-define-kasan_cache_create-for-generic-mode.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: kasan: only define kasan_cache_create for Generic mode
Date: Mon, 5 Sep 2022 23:05:33 +0200
Right now, kasan_cache_create() assigns SLAB_KASAN for all KASAN modes and
then sets up metadata-related cache parameters for the Generic mode.
SLAB_KASAN is used in two places:
1. In slab_ksize() to account for per-object metadata when
calculating the size of the accessible memory within the object.
2. In slab_common.c via kasan_never_merge() to prevent merging of
caches with per-object metadata.
Both cases are only relevant when per-object metadata is present, which is
only the case with the Generic mode.
Thus, assign SLAB_KASAN and define kasan_cache_create() only for the
Generic mode.
Also update the SLAB_KASAN-related comment.
Link: https://lkml.kernel.org/r/61faa2aa1906e2d02c97d00ddf99ce8911dda095.1662411799.git.andreyknvl@xxxxxxxxxx
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Reviewed-by: Marco Elver <elver@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx>
Cc: Peter Collingbourne <pcc@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/kasan.h | 18 ++++++------------
include/linux/slab.h | 2 +-
mm/kasan/common.c | 16 ----------------
mm/kasan/generic.c | 17 ++++++++++++++++-
4 files changed, 23 insertions(+), 30 deletions(-)
--- a/include/linux/kasan.h~kasan-only-define-kasan_cache_create-for-generic-mode
+++ a/include/linux/kasan.h
@@ -128,15 +128,6 @@ static __always_inline void kasan_unpois
__kasan_unpoison_pages(page, order, init);
}
-void __kasan_cache_create(struct kmem_cache *cache, unsigned int *size,
- slab_flags_t *flags);
-static __always_inline void kasan_cache_create(struct kmem_cache *cache,
- unsigned int *size, slab_flags_t *flags)
-{
- if (kasan_enabled())
- __kasan_cache_create(cache, size, flags);
-}
-
void __kasan_cache_create_kmalloc(struct kmem_cache *cache);
static __always_inline void kasan_cache_create_kmalloc(struct kmem_cache *cache)
{
@@ -260,9 +251,6 @@ static inline void kasan_poison_pages(st
bool init) {}
static inline void kasan_unpoison_pages(struct page *page, unsigned int order,
bool init) {}
-static inline void kasan_cache_create(struct kmem_cache *cache,
- unsigned int *size,
- slab_flags_t *flags) {}
static inline void kasan_cache_create_kmalloc(struct kmem_cache *cache) {}
static inline void kasan_poison_slab(struct slab *slab) {}
static inline void kasan_unpoison_object_data(struct kmem_cache *cache,
@@ -316,6 +304,8 @@ static inline void kasan_unpoison_task_s
size_t kasan_metadata_size(struct kmem_cache *cache);
slab_flags_t kasan_never_merge(void);
+void kasan_cache_create(struct kmem_cache *cache, unsigned int *size,
+ slab_flags_t *flags);
void kasan_cache_shrink(struct kmem_cache *cache);
void kasan_cache_shutdown(struct kmem_cache *cache);
@@ -334,6 +324,10 @@ static inline slab_flags_t kasan_never_m
{
return 0;
}
+/* And no cache-related metadata initialization is required. */
+static inline void kasan_cache_create(struct kmem_cache *cache,
+ unsigned int *size,
+ slab_flags_t *flags) {}
static inline void kasan_cache_shrink(struct kmem_cache *cache) {}
static inline void kasan_cache_shutdown(struct kmem_cache *cache) {}
--- a/include/linux/slab.h~kasan-only-define-kasan_cache_create-for-generic-mode
+++ a/include/linux/slab.h
@@ -106,7 +106,7 @@
# define SLAB_ACCOUNT 0
#endif
-#ifdef CONFIG_KASAN
+#ifdef CONFIG_KASAN_GENERIC
#define SLAB_KASAN ((slab_flags_t __force)0x08000000U)
#else
#define SLAB_KASAN 0
--- a/mm/kasan/common.c~kasan-only-define-kasan_cache_create-for-generic-mode
+++ a/mm/kasan/common.c
@@ -110,22 +110,6 @@ void __kasan_poison_pages(struct page *p
KASAN_PAGE_FREE, init);
}
-void __kasan_cache_create(struct kmem_cache *cache, unsigned int *size,
- slab_flags_t *flags)
-{
- /*
- * SLAB_KASAN is used to mark caches as ones that are sanitized by
- * KASAN. Currently this flag is used in two places:
- * 1. In slab_ksize() when calculating the size of the accessible
- * memory within the object.
- * 2. In slab_common.c to prevent merging of sanitized caches.
- */
- *flags |= SLAB_KASAN;
-
- if (kasan_requires_meta())
- kasan_init_cache_meta(cache, size);
-}
-
void __kasan_cache_create_kmalloc(struct kmem_cache *cache)
{
cache->kasan_info.is_kmalloc = true;
--- a/mm/kasan/generic.c~kasan-only-define-kasan_cache_create-for-generic-mode
+++ a/mm/kasan/generic.c
@@ -352,11 +352,26 @@ static inline unsigned int optimal_redzo
object_size <= (1 << 16) - 1024 ? 1024 : 2048;
}
-void kasan_init_cache_meta(struct kmem_cache *cache, unsigned int *size)
+void kasan_cache_create(struct kmem_cache *cache, unsigned int *size,
+ slab_flags_t *flags)
{
unsigned int ok_size;
unsigned int optimal_size;
+ if (!kasan_requires_meta())
+ return;
+
+ /*
+ * SLAB_KASAN is used to mark caches that are sanitized by KASAN
+ * and that thus have per-object metadata.
+ * Currently this flag is used in two places:
+ * 1. In slab_ksize() to account for per-object metadata when
+ * calculating the size of the accessible memory within the object.
+ * 2. In slab_common.c via kasan_never_merge() to prevent merging of
+ * caches with per-object metadata.
+ */
+ *flags |= SLAB_KASAN;
+
ok_size = *size;
/* Add alloc meta into redzone. */
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
kasan-check-kasan_no_free_meta-in-__kasan_metadata_size.patch
kasan-rename-kasan_set__info-to-kasan_save__info.patch
kasan-move-is_kmalloc-check-out-of-save_alloc_info.patch
kasan-split-save_alloc_info-implementations.patch
kasan-drop-config_kasan_tags_identify.patch
kasan-introduce-kasan_print_aux_stacks.patch
kasan-introduce-kasan_get_alloc_track.patch
kasan-introduce-kasan_init_object_meta.patch
kasan-clear-metadata-functions-for-tag-based-modes.patch
kasan-move-kasan_get__meta-to-genericc.patch
kasan-introduce-kasan_requires_meta.patch
kasan-introduce-kasan_init_cache_meta.patch
kasan-drop-config_kasan_generic-check-from-kasan_init_cache_meta.patch
kasan-only-define-kasan_metadata_size-for-generic-mode.patch
kasan-only-define-kasan_never_merge-for-generic-mode.patch
kasan-only-define-metadata-offsets-for-generic-mode.patch
kasan-only-define-metadata-structs-for-generic-mode.patch
kasan-only-define-kasan_cache_create-for-generic-mode.patch
kasan-pass-tagged-pointers-to-kasan_save_alloc-free_info.patch
kasan-move-kasan_get_alloc-free_track-definitions.patch
kasan-cosmetic-changes-in-reportc.patch
kasan-use-virt_addr_valid-in-kasan_addr_to_page-slab.patch
kasan-use-kasan_addr_to_slab-in-print_address_description.patch
kasan-make-kasan_addr_to_page-static.patch
kasan-simplify-print_report.patch
kasan-introduce-complete_report_info.patch
kasan-fill-in-cache-and-object-in-complete_report_info.patch
kasan-rework-function-arguments-in-reportc.patch
kasan-introduce-kasan_complete_mode_report_info.patch
kasan-implement-stack-ring-for-tag-based-modes.patch
kasan-support-kasanstacktrace-for-sw_tags.patch
kasan-dynamically-allocate-stack-ring-entries.patch
kasan-better-identify-bug-types-for-tag-based-modes.patch
kasan-add-another-use-after-free-test.patch
kasan-move-tests-to-mm-kasan.patch
