mm/kasan: use SLAB_NO_MERGE flag instead of an empty constructor

Use SLAB_NO_MERGE flag to prevent merging instead of providing an empty
constructor.  Using an empty constructor in this manner is an abuse of
slab interface.

The SLAB_NO_MERGE flag should be used with caution, but in this case, it
is acceptable as the cache is intended solely for debugging purposes.

No functional changes intended.

Link: https://lkml.kernel.org/r/20250318015926.1629748-1-harry.yoo@oracle.com
Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Acked-by: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Harry Yoo
2025-03-18 10:59:26 +09:00
committed by Andrew Morton
parent 7a95a05f15
commit 7fa46cdfff

View File

@@ -1073,14 +1073,11 @@ static void kmem_cache_rcu_uaf(struct kunit *test)
kmem_cache_destroy(cache);
}
static void empty_cache_ctor(void *object) { }
static void kmem_cache_double_destroy(struct kunit *test)
{
struct kmem_cache *cache;
/* Provide a constructor to prevent cache merging. */
cache = kmem_cache_create("test_cache", 200, 0, 0, empty_cache_ctor);
cache = kmem_cache_create("test_cache", 200, 0, SLAB_NO_MERGE, NULL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache);
kmem_cache_destroy(cache);
KUNIT_EXPECT_KASAN_FAIL(test, kmem_cache_destroy(cache));