summaryrefslogtreecommitdiffstats
path: root/lib/slub_kunit.c
blob: d4a3730b08fa7e175a8bad91a8722d476b9e05be (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
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");