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authorAndrey Konovalov <andreyknvl@google.com>2022-09-05 23:05:33 +0200
committerAndrew Morton <akpm@linux-foundation.org>2022-10-03 14:02:59 -0700
commit682ed08924407b719fa0b1123a26971748d76ace (patch)
tree6df09870ef2e533849f80a547969b25459e9d04c /mm/kasan
parentbe95e13fcc6ded156c65ece01486d9cc33d22dc8 (diff)
downloadlinux-682ed08924407b719fa0b1123a26971748d76ace.tar.gz
kasan: only define kasan_cache_create for Generic mode
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@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/kasan')
-rw-r--r--mm/kasan/common.c16
-rw-r--r--mm/kasan/generic.c17
2 files changed, 16 insertions, 17 deletions
diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index c2690e938030..8efa63190951 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -110,22 +110,6 @@ void __kasan_poison_pages(struct page *page, unsigned int order, bool init)
 			     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;
diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
index 25333bf3c99f..f6bef347de87 100644
--- a/mm/kasan/generic.c
+++ b/mm/kasan/generic.c
@@ -352,11 +352,26 @@ static inline unsigned int optimal_redzone(unsigned int object_size)
 		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. */