Commit 28cd28a7 authored by Harry Yoo's avatar Harry Yoo Committed by Kees Cook
Browse files

lkdtm: use SLAB_NO_MERGE 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 soley for debugging purposes.

No functional changes intended.

Signed-off-by: default avatarHarry Yoo <harry.yoo@oracle.com>
Link: https://lore.kernel.org/r/20250318014533.1624852-1-harry.yoo@oracle.com


Signed-off-by: default avatarKees Cook <kees@kernel.org>
parent b4432656

drivers/misc/lkdtm/heap.c

+3 −14
Original line number Diff line number Diff line
@@ -355,23 +355,12 @@ static void lkdtm_SLAB_FREE_PAGE(void) 
	free_page(p);

}



/*

 * We have constructors to keep the caches distinctly separated without

 * needing to boot with "slab_nomerge".

 */

static void ctor_double_free(void *region)

{ }

static void ctor_a(void *region)

{ }

static void ctor_b(void *region)

{ }



void __init lkdtm_heap_init(void)

{

	double_free_cache = kmem_cache_create("lkdtm-heap-double_free",

					      64, 0, 0, ctor_double_free);

	a_cache = kmem_cache_create("lkdtm-heap-a", 64, 0, 0, ctor_a);

	b_cache = kmem_cache_create("lkdtm-heap-b", 64, 0, 0, ctor_b);

					      64, 0, SLAB_NO_MERGE, NULL);

	a_cache = kmem_cache_create("lkdtm-heap-a", 64, 0, SLAB_NO_MERGE, NULL);

	b_cache = kmem_cache_create("lkdtm-heap-b", 64, 0, SLAB_NO_MERGE, NULL);

}



void __exit lkdtm_heap_exit(void)