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4e1c44b3db
Add a test that will create cache, allocate one object, kfree_rcu() it and attempt to destroy it. As long as the usage of kvfree_rcu_barrier() in kmem_cache_destroy() works correctly, there should be no warnings in dmesg and the test should pass. Additionally add a test_leak_destroy() test that leaks an object on purpose and verifies that kmem_cache_destroy() catches it. Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
222 lines
5.1 KiB
C
222 lines
5.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <kunit/test.h>
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#include <kunit/test-bug.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/rcupdate.h>
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#include "../mm/slab.h"
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static struct kunit_resource resource;
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static int slab_errors;
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/*
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* Wrapper function for kmem_cache_create(), which reduces 2 parameters:
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* 'align' and 'ctor', and sets SLAB_SKIP_KFENCE flag to avoid getting an
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* object from kfence pool, where the operation could be caught by both
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* our test and kfence sanity check.
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*/
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static struct kmem_cache *test_kmem_cache_create(const char *name,
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unsigned int size, slab_flags_t flags)
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{
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struct kmem_cache *s = kmem_cache_create(name, size, 0,
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(flags | SLAB_NO_USER_FLAGS), NULL);
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s->flags |= SLAB_SKIP_KFENCE;
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return s;
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}
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static void test_clobber_zone(struct kunit *test)
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{
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struct kmem_cache *s = test_kmem_cache_create("TestSlub_RZ_alloc", 64,
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SLAB_RED_ZONE);
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u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
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kasan_disable_current();
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p[64] = 0x12;
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validate_slab_cache(s);
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KUNIT_EXPECT_EQ(test, 2, slab_errors);
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kasan_enable_current();
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kmem_cache_free(s, p);
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kmem_cache_destroy(s);
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}
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#ifndef CONFIG_KASAN
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static void test_next_pointer(struct kunit *test)
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{
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struct kmem_cache *s = test_kmem_cache_create("TestSlub_next_ptr_free",
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64, SLAB_POISON);
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u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
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unsigned long tmp;
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unsigned long *ptr_addr;
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kmem_cache_free(s, p);
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ptr_addr = (unsigned long *)(p + s->offset);
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tmp = *ptr_addr;
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p[s->offset] = ~p[s->offset];
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/*
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* Expecting three errors.
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* One for the corrupted freechain and the other one for the wrong
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* count of objects in use. The third error is fixing broken cache.
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*/
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validate_slab_cache(s);
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KUNIT_EXPECT_EQ(test, 3, slab_errors);
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/*
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* Try to repair corrupted freepointer.
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* Still expecting two errors. The first for the wrong count
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* of objects in use.
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* The second error is for fixing broken cache.
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*/
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*ptr_addr = tmp;
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slab_errors = 0;
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validate_slab_cache(s);
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KUNIT_EXPECT_EQ(test, 2, slab_errors);
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/*
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* Previous validation repaired the count of objects in use.
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* Now expecting no error.
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*/
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slab_errors = 0;
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validate_slab_cache(s);
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KUNIT_EXPECT_EQ(test, 0, slab_errors);
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kmem_cache_destroy(s);
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}
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static void test_first_word(struct kunit *test)
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{
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struct kmem_cache *s = test_kmem_cache_create("TestSlub_1th_word_free",
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64, SLAB_POISON);
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u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
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kmem_cache_free(s, p);
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*p = 0x78;
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validate_slab_cache(s);
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KUNIT_EXPECT_EQ(test, 2, slab_errors);
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kmem_cache_destroy(s);
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}
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static void test_clobber_50th_byte(struct kunit *test)
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{
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struct kmem_cache *s = test_kmem_cache_create("TestSlub_50th_word_free",
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64, SLAB_POISON);
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u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
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kmem_cache_free(s, p);
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p[50] = 0x9a;
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validate_slab_cache(s);
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KUNIT_EXPECT_EQ(test, 2, slab_errors);
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kmem_cache_destroy(s);
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}
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#endif
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static void test_clobber_redzone_free(struct kunit *test)
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{
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struct kmem_cache *s = test_kmem_cache_create("TestSlub_RZ_free", 64,
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SLAB_RED_ZONE);
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u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
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kasan_disable_current();
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kmem_cache_free(s, p);
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p[64] = 0xab;
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validate_slab_cache(s);
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KUNIT_EXPECT_EQ(test, 2, slab_errors);
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kasan_enable_current();
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kmem_cache_destroy(s);
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}
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static void test_kmalloc_redzone_access(struct kunit *test)
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{
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struct kmem_cache *s = test_kmem_cache_create("TestSlub_RZ_kmalloc", 32,
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SLAB_KMALLOC|SLAB_STORE_USER|SLAB_RED_ZONE);
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u8 *p = __kmalloc_cache_noprof(s, GFP_KERNEL, 18);
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kasan_disable_current();
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/* Suppress the -Warray-bounds warning */
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OPTIMIZER_HIDE_VAR(p);
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p[18] = 0xab;
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p[19] = 0xab;
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validate_slab_cache(s);
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KUNIT_EXPECT_EQ(test, 2, slab_errors);
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kasan_enable_current();
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kmem_cache_free(s, p);
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kmem_cache_destroy(s);
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}
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struct test_kfree_rcu_struct {
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struct rcu_head rcu;
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};
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static void test_kfree_rcu(struct kunit *test)
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{
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struct kmem_cache *s = test_kmem_cache_create("TestSlub_kfree_rcu",
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sizeof(struct test_kfree_rcu_struct),
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SLAB_NO_MERGE);
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struct test_kfree_rcu_struct *p = kmem_cache_alloc(s, GFP_KERNEL);
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kfree_rcu(p, rcu);
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kmem_cache_destroy(s);
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KUNIT_EXPECT_EQ(test, 0, slab_errors);
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}
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static void test_leak_destroy(struct kunit *test)
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{
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struct kmem_cache *s = test_kmem_cache_create("TestSlub_kfree_rcu",
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64, SLAB_NO_MERGE);
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kmem_cache_alloc(s, GFP_KERNEL);
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kmem_cache_destroy(s);
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KUNIT_EXPECT_EQ(test, 1, slab_errors);
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}
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static int test_init(struct kunit *test)
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{
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slab_errors = 0;
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kunit_add_named_resource(test, NULL, NULL, &resource,
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"slab_errors", &slab_errors);
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return 0;
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}
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static struct kunit_case test_cases[] = {
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KUNIT_CASE(test_clobber_zone),
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#ifndef CONFIG_KASAN
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KUNIT_CASE(test_next_pointer),
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KUNIT_CASE(test_first_word),
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KUNIT_CASE(test_clobber_50th_byte),
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#endif
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KUNIT_CASE(test_clobber_redzone_free),
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KUNIT_CASE(test_kmalloc_redzone_access),
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KUNIT_CASE(test_kfree_rcu),
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KUNIT_CASE(test_leak_destroy),
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{}
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};
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static struct kunit_suite test_suite = {
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.name = "slub_test",
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.init = test_init,
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.test_cases = test_cases,
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};
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kunit_test_suite(test_suite);
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MODULE_LICENSE("GPL");
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