1 files changed, 328 insertions, 0 deletions
diff --git a/lib/tests/slub_kunit.c b/lib/tests/slub_kunit.c
new file mode 100644
index 000000000000..d47c472b0520
--- /dev/null
+++ b/lib/tests/slub_kunit.c
@@ -0,0 +1,328 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <kunit/test.h>
+#include <kunit/test-bug.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/rcupdate.h>
+#include <linux/delay.h>
+#include "../mm/slab.h"
+
+static struct kunit_resource resource;
+static int slab_errors;
+
+/*
+ * Wrapper function for kmem_cache_create(), which reduces 2 parameters:
+ * 'align' and 'ctor', and sets SLAB_SKIP_KFENCE flag to avoid getting an
+ * object from kfence pool, where the operation could be caught by both
+ * our test and kfence sanity check.
+ */
+static struct kmem_cache *test_kmem_cache_create(const char *name,
+				unsigned int size, slab_flags_t flags)
+{
+	struct kmem_cache *s = kmem_cache_create(name, size, 0,
+					(flags | SLAB_NO_USER_FLAGS), NULL);
+	s->flags |= SLAB_SKIP_KFENCE;
+	return s;
+}
+
+static void test_clobber_zone(struct kunit *test)
+{
+	struct kmem_cache *s = test_kmem_cache_create("TestSlub_RZ_alloc", 64,
+							SLAB_RED_ZONE);
+	u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
+
+	kasan_disable_current();
+	p[64] = 0x12;
+
+	validate_slab_cache(s);
+	KUNIT_EXPECT_EQ(test, 2, slab_errors);
+
+	kasan_enable_current();
+	kmem_cache_free(s, p);
+	kmem_cache_destroy(s);
+}
+
+#ifndef CONFIG_KASAN
+static void test_next_pointer(struct kunit *test)
+{
+	struct kmem_cache *s = test_kmem_cache_create("TestSlub_next_ptr_free",
+							64, SLAB_POISON);
+	u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
+	unsigned long tmp;
+	unsigned long *ptr_addr;
+
+	kmem_cache_free(s, p);
+
+	ptr_addr = (unsigned long *)(p + s->offset);
+	tmp = *ptr_addr;
+	p[s->offset] = ~p[s->offset];
+
+	/*
+	 * Expecting three errors.
+	 * One for the corrupted freechain and the other one for the wrong
+	 * count of objects in use. The third error is fixing broken cache.
+	 */
+	validate_slab_cache(s);
+	KUNIT_EXPECT_EQ(test, 3, slab_errors);
+
+	/*
+	 * Try to repair corrupted freepointer.
+	 * Still expecting two errors. The first for the wrong count
+	 * of objects in use.
+	 * The second error is for fixing broken cache.
+	 */
+	*ptr_addr = tmp;
+	slab_errors = 0;
+
+	validate_slab_cache(s);
+	KUNIT_EXPECT_EQ(test, 2, slab_errors);
+
+	/*
+	 * Previous validation repaired the count of objects in use.
+	 * Now expecting no error.
+	 */
+	slab_errors = 0;
+	validate_slab_cache(s);
+	KUNIT_EXPECT_EQ(test, 0, slab_errors);
+
+	kmem_cache_destroy(s);
+}
+
+static void test_first_word(struct kunit *test)
+{
+	struct kmem_cache *s = test_kmem_cache_create("TestSlub_1th_word_free",
+							64, SLAB_POISON);
+	u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
+
+	kmem_cache_free(s, p);
+	*p = 0x78;
+
+	validate_slab_cache(s);
+	KUNIT_EXPECT_EQ(test, 2, slab_errors);
+
+	kmem_cache_destroy(s);
+}
+
+static void test_clobber_50th_byte(struct kunit *test)
+{
+	struct kmem_cache *s = test_kmem_cache_create("TestSlub_50th_word_free",
+							64, SLAB_POISON);
+	u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
+
+	kmem_cache_free(s, p);
+	p[50] = 0x9a;
+
+	validate_slab_cache(s);
+	KUNIT_EXPECT_EQ(test, 2, slab_errors);
+
+	kmem_cache_destroy(s);
+}
+#endif
+
+static void test_clobber_redzone_free(struct kunit *test)
+{
+	struct kmem_cache *s = test_kmem_cache_create("TestSlub_RZ_free", 64,
+							SLAB_RED_ZONE);
+	u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
+
+	kasan_disable_current();
+	kmem_cache_free(s, p);
+	p[64] = 0xab;
+
+	validate_slab_cache(s);
+	KUNIT_EXPECT_EQ(test, 2, slab_errors);
+
+	kasan_enable_current();
+	kmem_cache_destroy(s);
+}
+
+static void test_kmalloc_redzone_access(struct kunit *test)
+{
+	struct kmem_cache *s = test_kmem_cache_create("TestSlub_RZ_kmalloc", 32,
+				SLAB_KMALLOC|SLAB_STORE_USER|SLAB_RED_ZONE);
+	u8 *p = alloc_hooks(__kmalloc_cache_noprof(s, GFP_KERNEL, 18));
+
+	kasan_disable_current();
+
+	/* Suppress the -Warray-bounds warning */
+	OPTIMIZER_HIDE_VAR(p);
+	p[18] = 0xab;
+	p[19] = 0xab;
+
+	validate_slab_cache(s);
+	KUNIT_EXPECT_EQ(test, 2, slab_errors);
+
+	kasan_enable_current();
+	kmem_cache_free(s, p);
+	kmem_cache_destroy(s);
+}
+
+struct test_kfree_rcu_struct {
+	struct rcu_head rcu;
+};
+
+static void test_kfree_rcu(struct kunit *test)
+{
+	struct kmem_cache *s;
+	struct test_kfree_rcu_struct *p;
+
+	if (IS_BUILTIN(CONFIG_SLUB_KUNIT_TEST))
+		kunit_skip(test, "can't do kfree_rcu() when test is built-in");
+
+	s = test_kmem_cache_create("TestSlub_kfree_rcu",
+				   sizeof(struct test_kfree_rcu_struct),
+				   SLAB_NO_MERGE);
+	p = kmem_cache_alloc(s, GFP_KERNEL);
+
+	kfree_rcu(p, rcu);
+	kmem_cache_destroy(s);
+
+	KUNIT_EXPECT_EQ(test, 0, slab_errors);
+}
+
+struct cache_destroy_work {
+	struct work_struct work;
+	struct kmem_cache *s;
+};
+
+static void cache_destroy_workfn(struct work_struct *w)
+{
+	struct cache_destroy_work *cdw;
+
+	cdw = container_of(w, struct cache_destroy_work, work);
+	kmem_cache_destroy(cdw->s);
+}
+
+#define KMEM_CACHE_DESTROY_NR 10
+
+static void test_kfree_rcu_wq_destroy(struct kunit *test)
+{
+	struct test_kfree_rcu_struct *p;
+	struct cache_destroy_work cdw;
+	struct workqueue_struct *wq;
+	struct kmem_cache *s;
+	unsigned int delay;
+	int i;
+
+	if (IS_BUILTIN(CONFIG_SLUB_KUNIT_TEST))
+		kunit_skip(test, "can't do kfree_rcu() when test is built-in");
+
+	INIT_WORK_ONSTACK(&cdw.work, cache_destroy_workfn);
+	wq = alloc_workqueue("test_kfree_rcu_destroy_wq",
+			WQ_HIGHPRI | WQ_UNBOUND | WQ_MEM_RECLAIM, 0);
+
+	if (!wq)
+		kunit_skip(test, "failed to alloc wq");
+
+	for (i = 0; i < KMEM_CACHE_DESTROY_NR; i++) {
+		s = test_kmem_cache_create("TestSlub_kfree_rcu_wq_destroy",
+				sizeof(struct test_kfree_rcu_struct),
+				SLAB_NO_MERGE);
+
+		if (!s)
+			kunit_skip(test, "failed to create cache");
+
+		delay = get_random_u8();
+		p = kmem_cache_alloc(s, GFP_KERNEL);
+		kfree_rcu(p, rcu);
+
+		cdw.s = s;
+
+		msleep(delay);
+		queue_work(wq, &cdw.work);
+		flush_work(&cdw.work);
+	}
+
+	destroy_workqueue(wq);
+	KUNIT_EXPECT_EQ(test, 0, slab_errors);
+}
+
+static void test_leak_destroy(struct kunit *test)
+{
+	struct kmem_cache *s = test_kmem_cache_create("TestSlub_leak_destroy",
+							64, SLAB_NO_MERGE);
+	kmem_cache_alloc(s, GFP_KERNEL);
+
+	kmem_cache_destroy(s);
+
+	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;
+
+	kunit_add_named_resource(test, NULL, NULL, &resource,
+					"slab_errors", &slab_errors);
+	return 0;
+}
+
+static struct kunit_case test_cases[] = {
+	KUNIT_CASE(test_clobber_zone),
+
+#ifndef CONFIG_KASAN
+	KUNIT_CASE(test_next_pointer),
+	KUNIT_CASE(test_first_word),
+	KUNIT_CASE(test_clobber_50th_byte),
+#endif
+
+	KUNIT_CASE(test_clobber_redzone_free),
+	KUNIT_CASE(test_kmalloc_redzone_access),
+	KUNIT_CASE(test_kfree_rcu),
+	KUNIT_CASE(test_kfree_rcu_wq_destroy),
+	KUNIT_CASE(test_leak_destroy),
+	KUNIT_CASE(test_krealloc_redzone_zeroing),
+	{}
+};
+
+static struct kunit_suite test_suite = {
+	.name = "slub_test",
+	.init = test_init,
+	.test_cases = test_cases,
+};
+kunit_test_suite(test_suite);
+
+MODULE_LICENSE("GPL");