From 28cd28a752058bf98b38013039bbde81df48b932 Mon Sep 17 00:00:00 2001 From: Harry Yoo Date: Tue, 18 Mar 2025 10:45:33 +0900 Subject: [PATCH] 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: Harry Yoo Link: https://lore.kernel.org/r/20250318014533.1624852-1-harry.yoo@oracle.com Signed-off-by: Kees Cook --- drivers/misc/lkdtm/heap.c | 17 +++-------------- 1 file changed, 3 insertions(+), 14 deletions(-) diff --git a/drivers/misc/lkdtm/heap.c b/drivers/misc/lkdtm/heap.c index b1b316f99703..c1a05b935894 100644 --- a/drivers/misc/lkdtm/heap.c +++ b/drivers/misc/lkdtm/heap.c @@ -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) -- 2.50.1