aboutsummaryrefslogtreecommitdiff
path: root/lib/test_meminit.c
blob: 9729f271d15041ac1930eb85922b81ba094a574f (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
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
// SPDX-License-Identifier: GPL-2.0
/*
 * Test cases for SL[AOU]B/page initialization at alloc/free time.
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/vmalloc.h>

#define GARBAGE_INT (0x09A7BA9E)
#define GARBAGE_BYTE (0x9E)

#define REPORT_FAILURES_IN_FN() \
	do {	\
		if (failures)	\
			pr_info("%s failed %d out of %d times\n",	\
				__func__, failures, num_tests);		\
		else		\
			pr_info("all %d tests in %s passed\n",		\
				num_tests, __func__);			\
	} while (0)

/* Calculate the number of uninitialized bytes in the buffer. */
static int __init count_nonzero_bytes(void *ptr, size_t size)
{
	int i, ret = 0;
	unsigned char *p = (unsigned char *)ptr;

	for (i = 0; i < size; i++)
		if (p[i])
			ret++;
	return ret;
}

/* Fill a buffer with garbage, skipping |skip| first bytes. */
static void __init fill_with_garbage_skip(void *ptr, int size, size_t skip)
{
	unsigned int *p = (unsigned int *)((char *)ptr + skip);
	int i = 0;

	WARN_ON(skip > size);
	size -= skip;

	while (size >= sizeof(*p)) {
		p[i] = GARBAGE_INT;
		i++;
		size -= sizeof(*p);
	}
	if (size)
		memset(&p[i], GARBAGE_BYTE, size);
}

static void __init fill_with_garbage(void *ptr, size_t size)
{
	fill_with_garbage_skip(ptr, size, 0);
}

static int __init do_alloc_pages_order(int order, int *total_failures)
{
	struct page *page;
	void *buf;
	size_t size = PAGE_SIZE << order;

	page = alloc_pages(GFP_KERNEL, order);
	buf = page_address(page);
	fill_with_garbage(buf, size);
	__free_pages(page, order);

	page = alloc_pages(GFP_KERNEL, order);
	buf = page_address(page);
	if (count_nonzero_bytes(buf, size))
		(*total_failures)++;
	fill_with_garbage(buf, size);
	__free_pages(page, order);
	return 1;
}

/* Test the page allocator by calling alloc_pages with different orders. */
static int __init test_pages(int *total_failures)
{
	int failures = 0, num_tests = 0;
	int i;

	for (i = 0; i < 10; i++)
		num_tests += do_alloc_pages_order(i, &failures);

	REPORT_FAILURES_IN_FN();
	*total_failures += failures;
	return num_tests;
}

/* Test kmalloc() with given parameters. */
static int __init do_kmalloc_size(size_t size, int *total_failures)
{
	void *buf;

	buf = kmalloc(size, GFP_KERNEL);
	fill_with_garbage(buf, size);
	kfree(buf);

	buf = kmalloc(size, GFP_KERNEL);
	if (count_nonzero_bytes(buf, size))
		(*total_failures)++;
	fill_with_garbage(buf, size);
	kfree(buf);
	return 1;
}

/* Test vmalloc() with given parameters. */
static int __init do_vmalloc_size(size_t size, int *total_failures)
{
	void *buf;

	buf = vmalloc(size);
	fill_with_garbage(buf, size);
	vfree(buf);

	buf = vmalloc(size);
	if (count_nonzero_bytes(buf, size))
		(*total_failures)++;
	fill_with_garbage(buf, size);
	vfree(buf);
	return 1;
}

/* Test kmalloc()/vmalloc() by allocating objects of different sizes. */
static int __init test_kvmalloc(int *total_failures)
{
	int failures = 0, num_tests = 0;
	int i, size;

	for (i = 0; i < 20; i++) {
		size = 1 << i;
		num_tests += do_kmalloc_size(size, &failures);
		num_tests += do_vmalloc_size(size, &failures);
	}

	REPORT_FAILURES_IN_FN();
	*total_failures += failures;
	return num_tests;
}

#define CTOR_BYTES (sizeof(unsigned int))
#define CTOR_PATTERN (0x41414141)
/* Initialize the first 4 bytes of the object. */
static void test_ctor(void *obj)
{
	*(unsigned int *)obj = CTOR_PATTERN;
}

/*
 * Check the invariants for the buffer allocated from a slab cache.
 * If the cache has a test constructor, the first 4 bytes of the object must
 * always remain equal to CTOR_PATTERN.
 * If the cache isn't an RCU-typesafe one, or if the allocation is done with
 * __GFP_ZERO, then the object contents must be zeroed after allocation.
 * If the cache is an RCU-typesafe one, the object contents must never be
 * zeroed after the first use. This is checked by memcmp() in
 * do_kmem_cache_size().
 */
static bool __init check_buf(void *buf, int size, bool want_ctor,
			     bool want_rcu, bool want_zero)
{
	int bytes;
	bool fail = false;

	bytes = count_nonzero_bytes(buf, size);
	WARN_ON(want_ctor && want_zero);
	if (want_zero)
		return bytes;
	if (want_ctor) {
		if (*(unsigned int *)buf != CTOR_PATTERN)
			fail = 1;
	} else {
		if (bytes)
			fail = !want_rcu;
	}
	return fail;
}

/*
 * Test kmem_cache with given parameters:
 *  want_ctor - use a constructor;
 *  want_rcu - use SLAB_TYPESAFE_BY_RCU;
 *  want_zero - use __GFP_ZERO.
 */
static int __init do_kmem_cache_size(size_t size, bool want_ctor,
				     bool want_rcu, bool want_zero,
				     int *total_failures)
{
	struct kmem_cache *c;
	int iter;
	bool fail = false;
	gfp_t alloc_mask = GFP_KERNEL | (want_zero ? __GFP_ZERO : 0);
	void *buf, *buf_copy;

	c = kmem_cache_create("test_cache", size, 1,
			      want_rcu ? SLAB_TYPESAFE_BY_RCU : 0,
			      want_ctor ? test_ctor : NULL);
	for (iter = 0; iter < 10; iter++) {
		buf = kmem_cache_alloc(c, alloc_mask);
		/* Check that buf is zeroed, if it must be. */
		fail = check_buf(buf, size, want_ctor, want_rcu, want_zero);
		fill_with_garbage_skip(buf, size, want_ctor ? CTOR_BYTES : 0);

		if (!want_rcu) {
			kmem_cache_free(c, buf);
			continue;
		}

		/*
		 * If this is an RCU cache, use a critical section to ensure we
		 * can touch objects after they're freed.
		 */
		rcu_read_lock();
		/*
		 * Copy the buffer to check that it's not wiped on
		 * free().
		 */
		buf_copy = kmalloc(size, GFP_ATOMIC);
		if (buf_copy)
			memcpy(buf_copy, buf, size);

		kmem_cache_free(c, buf);
		/*
		 * Check that |buf| is intact after kmem_cache_free().
		 * |want_zero| is false, because we wrote garbage to
		 * the buffer already.
		 */
		fail |= check_buf(buf, size, want_ctor, want_rcu,
				  false);
		if (buf_copy) {
			fail |= (bool)memcmp(buf, buf_copy, size);
			kfree(buf_copy);
		}
		rcu_read_unlock();
	}
	kmem_cache_destroy(c);

	*total_failures += fail;
	return 1;
}

/*
 * Check that the data written to an RCU-allocated object survives
 * reallocation.
 */
static int __init do_kmem_cache_rcu_persistent(int size, int *total_failures)
{
	struct kmem_cache *c;
	void *buf, *buf_contents, *saved_ptr;
	void **used_objects;
	int i, iter, maxiter = 1024;
	bool fail = false;

	c = kmem_cache_create("test_cache", size, size, SLAB_TYPESAFE_BY_RCU,
			      NULL);
	buf = kmem_cache_alloc(c, GFP_KERNEL);
	saved_ptr = buf;
	fill_with_garbage(buf, size);
	buf_contents = kmalloc(size, GFP_KERNEL);
	if (!buf_contents)
		goto out;
	used_objects = kmalloc_array(maxiter, sizeof(void *), GFP_KERNEL);
	if (!used_objects) {
		kfree(buf_contents);
		goto out;
	}
	memcpy(buf_contents, buf, size);
	kmem_cache_free(c, buf);
	/*
	 * Run for a fixed number of iterations. If we never hit saved_ptr,
	 * assume the test passes.
	 */
	for (iter = 0; iter < maxiter; iter++) {
		buf = kmem_cache_alloc(c, GFP_KERNEL);
		used_objects[iter] = buf;
		if (buf == saved_ptr) {
			fail = memcmp(buf_contents, buf, size);
			for (i = 0; i <= iter; i++)
				kmem_cache_free(c, used_objects[i]);
			goto free_out;
		}
	}

free_out:
	kmem_cache_destroy(c);
	kfree(buf_contents);
	kfree(used_objects);
out:
	*total_failures += fail;
	return 1;
}

/*
 * Test kmem_cache allocation by creating caches of different sizes, with and
 * without constructors, with and without SLAB_TYPESAFE_BY_RCU.
 */
static int __init test_kmemcache(int *total_failures)
{
	int failures = 0, num_tests = 0;
	int i, flags, size;
	bool ctor, rcu, zero;

	for (i = 0; i < 10; i++) {
		size = 8 << i;
		for (flags = 0; flags < 8; flags++) {
			ctor = flags & 1;
			rcu = flags & 2;
			zero = flags & 4;
			if (ctor & zero)
				continue;
			num_tests += do_kmem_cache_size(size, ctor, rcu, zero,
							&failures);
		}
	}
	REPORT_FAILURES_IN_FN();
	*total_failures += failures;
	return num_tests;
}

/* Test the behavior of SLAB_TYPESAFE_BY_RCU caches of different sizes. */
static int __init test_rcu_persistent(int *total_failures)
{
	int failures = 0, num_tests = 0;
	int i, size;

	for (i = 0; i < 10; i++) {
		size = 8 << i;
		num_tests += do_kmem_cache_rcu_persistent(size, &failures);
	}
	REPORT_FAILURES_IN_FN();
	*total_failures += failures;
	return num_tests;
}

/*
 * Run the tests. Each test function returns the number of executed tests and
 * updates |failures| with the number of failed tests.
 */
static int __init test_meminit_init(void)
{
	int failures = 0, num_tests = 0;

	num_tests += test_pages(&failures);
	num_tests += test_kvmalloc(&failures);
	num_tests += test_kmemcache(&failures);
	num_tests += test_rcu_persistent(&failures);

	if (failures == 0)
		pr_info("all %d tests passed!\n", num_tests);
	else
		pr_info("failures: %d out of %d\n", failures, num_tests);

	return failures ? -EINVAL : 0;
}
module_init(test_meminit_init);

MODULE_LICENSE("GPL");