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-rw-r--r--lib/slub_kunit.c190
1 files changed, 190 insertions, 0 deletions
diff --git a/lib/slub_kunit.c b/lib/slub_kunit.c
new file mode 100644
index 0000000000..d4a3730b08
--- /dev/null
+++ b/lib/slub_kunit.c
@@ -0,0 +1,190 @@
+// 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 "../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] = 0x12;
+
+ /*
+ * 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 = kmalloc_trace(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);
+}
+
+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),
+ {}
+};
+
+static struct kunit_suite test_suite = {
+ .name = "slub_test",
+ .init = test_init,
+ .test_cases = test_cases,
+};
+kunit_test_suite(test_suite);
+
+MODULE_LICENSE("GPL");