Commit 080c8579 authored by Feng Tang's avatar Feng Tang Committed by Vlastimil Babka
Browse files

mm/slub, kunit: Add testcase for krealloc redzone and zeroing 

Danilo Krummrich raised issue about krealloc+GFP_ZERO [1], and Vlastimil
suggested to add some test case which can sanity test the kmalloc-redzone
and zeroing by utilizing the kmalloc's 'orig_size' debug feature.

It covers the grow and shrink case of krealloc() re-using current kmalloc
object, and the case of re-allocating a new bigger object.

[1]. https://lore.kernel.org/lkml/20240812223707.32049-1-dakr@kernel.org/



Suggested-by: default avatarVlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarFeng Tang <feng.tang@intel.com>
Signed-off-by: default avatarVlastimil Babka <vbabka@suse.cz>
parent 5474d33c

lib/slub_kunit.c

+42 −0
Original line number Diff line number Diff line
@@ -192,6 +192,47 @@ static void test_leak_destroy(struct kunit *test) 
	KUNIT_EXPECT_EQ(test, 2, slab_errors);

}



static void test_krealloc_redzone_zeroing(struct kunit *test)

{

	u8 *p;

	int i;

	struct kmem_cache *s = test_kmem_cache_create("TestSlub_krealloc", 64,

				SLAB_KMALLOC|SLAB_STORE_USER|SLAB_RED_ZONE);



	p = alloc_hooks(__kmalloc_cache_noprof(s, GFP_KERNEL, 48));

	memset(p, 0xff, 48);



	kasan_disable_current();

	OPTIMIZER_HIDE_VAR(p);



	/* Test shrink */

	p = krealloc(p, 40, GFP_KERNEL | __GFP_ZERO);

	for (i = 40; i < 64; i++)

		KUNIT_EXPECT_EQ(test, p[i], SLUB_RED_ACTIVE);



	/* Test grow within the same 64B kmalloc object */

	p = krealloc(p, 56, GFP_KERNEL | __GFP_ZERO);

	for (i = 40; i < 56; i++)

		KUNIT_EXPECT_EQ(test, p[i], 0);

	for (i = 56; i < 64; i++)

		KUNIT_EXPECT_EQ(test, p[i], SLUB_RED_ACTIVE);



	validate_slab_cache(s);

	KUNIT_EXPECT_EQ(test, 0, slab_errors);



	memset(p, 0xff, 56);

	/* Test grow with allocating a bigger 128B object */

	p = krealloc(p, 112, GFP_KERNEL | __GFP_ZERO);

	for (i = 0; i < 56; i++)

		KUNIT_EXPECT_EQ(test, p[i], 0xff);

	for (i = 56; i < 112; i++)

		KUNIT_EXPECT_EQ(test, p[i], 0);



	kfree(p);

	kasan_enable_current();

	kmem_cache_destroy(s);

}



static int test_init(struct kunit *test)

{

	slab_errors = 0;
@@ -214,6 +255,7 @@ static struct kunit_case test_cases[] = { 
	KUNIT_CASE(test_kmalloc_redzone_access),

	KUNIT_CASE(test_kfree_rcu),

	KUNIT_CASE(test_leak_destroy),

	KUNIT_CASE(test_krealloc_redzone_zeroing),

	{}

};