The patch titled
Subject: kasan: test: prevent cache merging in kmem_cache_double_destroy
has been added to the -mm tree. Its filename is
kasan-test-prevent-cache-merging-in-kmem_cache_double_destroy.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/kasan-test-prevent-cache-merging-in-kmem_cache_double_destroy.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/kasan-test-prevent-cache-merging-in-kmem_cache_double_destroy.patch
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------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: kasan: test: prevent cache merging in kmem_cache_double_destroy
With HW_TAGS KASAN and kasan.stacktrace=off, the cache created in the
kmem_cache_double_destroy() test might get merged with an existing one.
Thus, the first kmem_cache_destroy() call won't actually destroy it but
will only decrease the refcount. This causes the test to fail.
Provide an empty constructor for the created cache to prevent the cache
from getting merged.
Link: https://lkml.kernel.org/r/b597bd434c49591d8af00ee3993a42c609dc9a59.1644346040.git.andreyknvl@xxxxxxxxxx
Fixes: f98f966cd750 ("kasan: test: add test case for double-kmem_cache_destroy()")
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Reviewed-by: Marco Elver <elver@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/test_kasan.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/lib/test_kasan.c~kasan-test-prevent-cache-merging-in-kmem_cache_double_destroy
+++ a/lib/test_kasan.c
@@ -869,11 +869,14 @@ static void kmem_cache_invalid_free(stru
kmem_cache_destroy(cache);
}
+static void empty_cache_ctor(void *object) { }
+
static void kmem_cache_double_destroy(struct kunit *test)
{
struct kmem_cache *cache;
- cache = kmem_cache_create("test_cache", 200, 0, 0, NULL);
+ /* Provide a constructor to prevent cache merging. */
+ cache = kmem_cache_create("test_cache", 200, 0, 0, empty_cache_ctor);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache);
kmem_cache_destroy(cache);
KUNIT_EXPECT_KASAN_FAIL(test, kmem_cache_destroy(cache));
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
kasan-test-prevent-cache-merging-in-kmem_cache_double_destroy.patch
kasan-page_alloc-deduplicate-should_skip_kasan_poison.patch
kasan-page_alloc-move-tag_clear_highpage-out-of-kernel_init_free_pages.patch
kasan-page_alloc-merge-kasan_free_pages-into-free_pages_prepare.patch
kasan-page_alloc-simplify-kasan_poison_pages-call-site.patch
kasan-page_alloc-init-memory-of-skipped-pages-on-free.patch
kasan-drop-skip_kasan_poison-variable-in-free_pages_prepare.patch
mm-clarify-__gfp_zerotags-comment.patch
kasan-only-apply-__gfp_zerotags-when-memory-is-zeroed.patch
kasan-page_alloc-refactor-init-checks-in-post_alloc_hook.patch
kasan-page_alloc-merge-kasan_alloc_pages-into-post_alloc_hook.patch
kasan-page_alloc-combine-tag_clear_highpage-calls-in-post_alloc_hook.patch
kasan-page_alloc-move-setpageskipkasanpoison-in-post_alloc_hook.patch
kasan-page_alloc-move-kernel_init_free_pages-in-post_alloc_hook.patch
kasan-page_alloc-rework-kasan_unpoison_pages-call-site.patch
kasan-clean-up-metadata-byte-definitions.patch
kasan-define-kasan_vmalloc_invalid-for-sw_tags.patch
kasan-x86-arm64-s390-rename-functions-for-modules-shadow.patch
kasan-vmalloc-drop-outdated-vm_kasan-comment.patch
kasan-reorder-vmalloc-hooks.patch
kasan-add-wrappers-for-vmalloc-hooks.patch
kasan-vmalloc-reset-tags-in-vmalloc-functions.patch
kasan-fork-reset-pointer-tags-of-vmapped-stacks.patch
kasan-arm64-reset-pointer-tags-of-vmapped-stacks.patch
kasan-vmalloc-add-vmalloc-tagging-for-sw_tags.patch
kasan-vmalloc-arm64-mark-vmalloc-mappings-as-pgprot_tagged.patch
kasan-vmalloc-unpoison-vm_alloc-pages-after-mapping.patch
kasan-mm-only-define-___gfp_skip_kasan_poison-with-hw_tags.patch
kasan-page_alloc-allow-skipping-unpoisoning-for-hw_tags.patch
kasan-page_alloc-allow-skipping-memory-init-for-hw_tags.patch
kasan-vmalloc-add-vmalloc-tagging-for-hw_tags.patch
kasan-vmalloc-only-tag-normal-vmalloc-allocations.patch
kasan-arm64-dont-tag-executable-vmalloc-allocations.patch
kasan-mark-kasan_arg_stacktrace-as-__initdata.patch
kasan-clean-up-feature-flags-for-hw_tags-mode.patch
kasan-add-kasanvmalloc-command-line-flag.patch
kasan-allow-enabling-kasan_vmalloc-and-sw-hw_tags.patch
arm64-select-kasan_vmalloc-for-sw-hw_tags-modes.patch
kasan-documentation-updates.patch
kasan-improve-vmalloc-tests.patch
