projects/linux·blob v7.2-rc7 · refs

439 lines · 10.3 KiB

1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Test cases for SL[AOU]B/page initialization at alloc/free time.
4 */
5#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
6
7#include <linux/init.h>
8#include <linux/kernel.h>
9#include <linux/mm.h>
10#include <linux/module.h>
11#include <linux/slab.h>
12#include <linux/string.h>
13#include <linux/vmalloc.h>
14
15#define GARBAGE_INT (0x09A7BA9E)
16#define GARBAGE_BYTE (0x9E)
17
18#define REPORT_FAILURES_IN_FN() \
19 do { \
20 if (failures) \
21 pr_info("%s failed %d out of %d times\n", \
22 __func__, failures, num_tests); \
23 else \
24 pr_info("all %d tests in %s passed\n", \
25 num_tests, __func__); \
26 } while (0)
27
28/* Calculate the number of uninitialized bytes in the buffer. */
29static int __init count_nonzero_bytes(void *ptr, size_t size)
30{
31 int i, ret = 0;
32 unsigned char *p = (unsigned char *)ptr;
33
34 for (i = 0; i < size; i++)
35 if (p[i])
36 ret++;
37 return ret;
38}
39
40/* Fill a buffer with garbage, skipping |skip| first bytes. */
41static void __init fill_with_garbage_skip(void *ptr, int size, size_t skip)
42{
43 unsigned int *p = (unsigned int *)((char *)ptr + skip);
44 int i = 0;
45
46 WARN_ON(skip > size);
47 size -= skip;
48
49 while (size >= sizeof(*p)) {
50 p[i] = GARBAGE_INT;
51 i++;
52 size -= sizeof(*p);
53 }
54 if (size)
55 memset(&p[i], GARBAGE_BYTE, size);
56}
57
58static void __init fill_with_garbage(void *ptr, size_t size)
59{
60 fill_with_garbage_skip(ptr, size, 0);
61}
62
63static int __init do_alloc_pages_order(int order, int *total_failures)
64{
65 struct page *page;
66 void *buf;
67 size_t size = PAGE_SIZE << order;
68
69 page = alloc_pages(GFP_KERNEL, order);
70 if (!page)
71 goto err;
72 buf = page_address(page);
73 fill_with_garbage(buf, size);
74 __free_pages(page, order);
75
76 page = alloc_pages(GFP_KERNEL, order);
77 if (!page)
78 goto err;
79 buf = page_address(page);
80 if (count_nonzero_bytes(buf, size))
81 (*total_failures)++;
82 fill_with_garbage(buf, size);
83 __free_pages(page, order);
84 return 1;
85err:
86 (*total_failures)++;
87 return 1;
88}
89
90/* Test the page allocator by calling alloc_pages with different orders. */
91static int __init test_pages(int *total_failures)
92{
93 int failures = 0, num_tests = 0;
94 int i;
95
96 for (i = 0; i < NR_PAGE_ORDERS; i++)
97 num_tests += do_alloc_pages_order(i, &failures);
98
99 REPORT_FAILURES_IN_FN();
100 *total_failures += failures;
101 return num_tests;
102}
103
104/* Test kmalloc() with given parameters. */
105static int __init do_kmalloc_size(size_t size, int *total_failures)
106{
107 void *buf;
108
109 buf = kmalloc(size, GFP_KERNEL);
110 if (!buf)
111 goto err;
112 fill_with_garbage(buf, size);
113 kfree(buf);
114
115 buf = kmalloc(size, GFP_KERNEL);
116 if (!buf)
117 goto err;
118 if (count_nonzero_bytes(buf, size))
119 (*total_failures)++;
120 fill_with_garbage(buf, size);
121 kfree(buf);
122 return 1;
123err:
124 (*total_failures)++;
125 return 1;
126}
127
128/* Test vmalloc() with given parameters. */
129static int __init do_vmalloc_size(size_t size, int *total_failures)
130{
131 void *buf;
132
133 buf = vmalloc(size);
134 if (!buf)
135 goto err;
136 fill_with_garbage(buf, size);
137 vfree(buf);
138
139 buf = vmalloc(size);
140 if (!buf)
141 goto err;
142 if (count_nonzero_bytes(buf, size))
143 (*total_failures)++;
144 fill_with_garbage(buf, size);
145 vfree(buf);
146 return 1;
147err:
148 (*total_failures)++;
149 return 1;
150}
151
152/* Test kmalloc()/vmalloc() by allocating objects of different sizes. */
153static int __init test_kvmalloc(int *total_failures)
154{
155 int failures = 0, num_tests = 0;
156 int i, size;
157
158 for (i = 0; i < 20; i++) {
159 size = 1 << i;
160 num_tests += do_kmalloc_size(size, &failures);
161 num_tests += do_vmalloc_size(size, &failures);
162 }
163
164 REPORT_FAILURES_IN_FN();
165 *total_failures += failures;
166 return num_tests;
167}
168
169#define CTOR_BYTES (sizeof(unsigned int))
170#define CTOR_PATTERN (0x41414141)
171/* Initialize the first 4 bytes of the object. */
172static void test_ctor(void *obj)
173{
174 *(unsigned int *)obj = CTOR_PATTERN;
175}
176
177/*
178 * Check the invariants for the buffer allocated from a slab cache.
179 * If the cache has a test constructor, the first 4 bytes of the object must
180 * always remain equal to CTOR_PATTERN.
181 * If the cache isn't an RCU-typesafe one, or if the allocation is done with
182 * __GFP_ZERO, then the object contents must be zeroed after allocation.
183 * If the cache is an RCU-typesafe one, the object contents must never be
184 * zeroed after the first use. This is checked by memcmp() in
185 * do_kmem_cache_size().
186 */
187static bool __init check_buf(void *buf, int size, bool want_ctor,
188 bool want_rcu, bool want_zero)
189{
190 int bytes;
191 bool fail = false;
192
193 bytes = count_nonzero_bytes(buf, size);
194 WARN_ON(want_ctor && want_zero);
195 if (want_zero)
196 return bytes;
197 if (want_ctor) {
198 if (*(unsigned int *)buf != CTOR_PATTERN)
199 fail = 1;
200 } else {
201 if (bytes)
202 fail = !want_rcu;
203 }
204 return fail;
205}
206
207#define BULK_SIZE 100
208static void *bulk_array[BULK_SIZE];
209
210/*
211 * Test kmem_cache with given parameters:
212 * want_ctor - use a constructor;
213 * want_rcu - use SLAB_TYPESAFE_BY_RCU;
214 * want_zero - use __GFP_ZERO.
215 */
216static int __init do_kmem_cache_size(size_t size, bool want_ctor,
217 bool want_rcu, bool want_zero,
218 int *total_failures)
219{
220 struct kmem_cache *c;
221 int iter;
222 bool fail = false;
223 gfp_t alloc_mask = GFP_KERNEL | (want_zero ? __GFP_ZERO : 0);
224 void *buf, *buf_copy;
225
226 c = kmem_cache_create("test_cache", size, 1,
227 want_rcu ? SLAB_TYPESAFE_BY_RCU : 0,
228 want_ctor ? test_ctor : NULL);
229 for (iter = 0; iter < 10; iter++) {
230 /* Do a test of bulk allocations */
231 if (!want_rcu && !want_ctor) {
232 if (!kmem_cache_alloc_bulk(c, alloc_mask, BULK_SIZE,
233 bulk_array)) {
234 fail = true;
235 } else {
236 int i;
237 for (i = 0; i < BULK_SIZE; i++)
238 fail |= check_buf(bulk_array[i], size, want_ctor, want_rcu, want_zero);
239 kmem_cache_free_bulk(c, BULK_SIZE, bulk_array);
240 }
241 }
242
243 buf = kmem_cache_alloc(c, alloc_mask);
244 /* Check that buf is zeroed, if it must be. */
245 fail |= check_buf(buf, size, want_ctor, want_rcu, want_zero);
246 fill_with_garbage_skip(buf, size, want_ctor ? CTOR_BYTES : 0);
247
248 if (!want_rcu) {
249 kmem_cache_free(c, buf);
250 continue;
251 }
252
253 /*
254 * If this is an RCU cache, use a critical section to ensure we
255 * can touch objects after they're freed.
256 */
257 rcu_read_lock();
258 /*
259 * Copy the buffer to check that it's not wiped on
260 * free().
261 */
262 buf_copy = kmalloc(size, GFP_ATOMIC);
263 if (buf_copy)
264 memcpy(buf_copy, buf, size);
265
266 kmem_cache_free(c, buf);
267 /*
268 * Check that |buf| is intact after kmem_cache_free().
269 * |want_zero| is false, because we wrote garbage to
270 * the buffer already.
271 */
272 fail |= check_buf(buf, size, want_ctor, want_rcu,
273 false);
274 if (buf_copy) {
275 fail |= (bool)memcmp(buf, buf_copy, size);
276 kfree(buf_copy);
277 }
278 rcu_read_unlock();
279 }
280 kmem_cache_destroy(c);
281
282 *total_failures += fail;
283 return 1;
284}
285
286/*
287 * Check that the data written to an RCU-allocated object survives
288 * reallocation.
289 */
290static int __init do_kmem_cache_rcu_persistent(int size, int *total_failures)
291{
292 struct kmem_cache *c;
293 void *buf, *buf_contents, *saved_ptr;
294 void **used_objects;
295 int i, iter, maxiter = 1024;
296 bool fail = false;
297
298 c = kmem_cache_create("test_cache", size, size, SLAB_TYPESAFE_BY_RCU,
299 NULL);
300 buf = kmem_cache_alloc(c, GFP_KERNEL);
301 if (!buf)
302 goto out;
303 saved_ptr = buf;
304 fill_with_garbage(buf, size);
305 buf_contents = kmalloc(size, GFP_KERNEL);
306 if (!buf_contents) {
307 kmem_cache_free(c, buf);
308 goto out;
309 }
310 used_objects = kmalloc_array(maxiter, sizeof(void *), GFP_KERNEL);
311 if (!used_objects) {
312 kmem_cache_free(c, buf);
313 kfree(buf_contents);
314 goto out;
315 }
316 memcpy(buf_contents, buf, size);
317 kmem_cache_free(c, buf);
318 /*
319 * Run for a fixed number of iterations. If we never hit saved_ptr,
320 * assume the test passes.
321 */
322 for (iter = 0; iter < maxiter; iter++) {
323 buf = kmem_cache_alloc(c, GFP_KERNEL);
324 used_objects[iter] = buf;
325 if (buf == saved_ptr) {
326 fail = memcmp(buf_contents, buf, size);
327 for (i = 0; i <= iter; i++)
328 kmem_cache_free(c, used_objects[i]);
329 goto free_out;
330 }
331 }
332
333 for (iter = 0; iter < maxiter; iter++)
334 kmem_cache_free(c, used_objects[iter]);
335
336free_out:
337 kfree(buf_contents);
338 kfree(used_objects);
339out:
340 kmem_cache_destroy(c);
341 *total_failures += fail;
342 return 1;
343}
344
345static int __init do_kmem_cache_size_bulk(int size, int *total_failures)
346{
347 struct kmem_cache *c;
348 int i, iter, maxiter = 1024;
349 int bytes;
350 bool fail = false;
351 void *objects[10];
352
353 c = kmem_cache_create("test_cache", size, size, 0, NULL);
354 for (iter = 0; (iter < maxiter) && !fail; iter++) {
355 if (!kmem_cache_alloc_bulk(c, GFP_KERNEL, ARRAY_SIZE(objects),
356 objects))
357 continue;
358
359 for (i = 0; i < ARRAY_SIZE(objects); i++) {
360 bytes = count_nonzero_bytes(objects[i], size);
361 if (bytes)
362 fail = true;
363 fill_with_garbage(objects[i], size);
364 }
365
366 kmem_cache_free_bulk(c, ARRAY_SIZE(objects), objects);
367 }
368 kmem_cache_destroy(c);
369 *total_failures += fail;
370 return 1;
371}
372
373/*
374 * Test kmem_cache allocation by creating caches of different sizes, with and
375 * without constructors, with and without SLAB_TYPESAFE_BY_RCU.
376 */
377static int __init test_kmemcache(int *total_failures)
378{
379 int failures = 0, num_tests = 0;
380 int i, flags, size;
381 bool ctor, rcu, zero;
382
383 for (i = 0; i < 10; i++) {
384 size = 8 << i;
385 for (flags = 0; flags < 8; flags++) {
386 ctor = flags & 1;
387 rcu = flags & 2;
388 zero = flags & 4;
389 if (ctor && zero)
390 continue;
391 num_tests += do_kmem_cache_size(size, ctor, rcu, zero,
392 &failures);
393 }
394 num_tests += do_kmem_cache_size_bulk(size, &failures);
395 }
396 REPORT_FAILURES_IN_FN();
397 *total_failures += failures;
398 return num_tests;
399}
400
401/* Test the behavior of SLAB_TYPESAFE_BY_RCU caches of different sizes. */
402static int __init test_rcu_persistent(int *total_failures)
403{
404 int failures = 0, num_tests = 0;
405 int i, size;
406
407 for (i = 0; i < 10; i++) {
408 size = 8 << i;
409 num_tests += do_kmem_cache_rcu_persistent(size, &failures);
410 }
411 REPORT_FAILURES_IN_FN();
412 *total_failures += failures;
413 return num_tests;
414}
415
416/*
417 * Run the tests. Each test function returns the number of executed tests and
418 * updates |failures| with the number of failed tests.
419 */
420static int __init test_meminit_init(void)
421{
422 int failures = 0, num_tests = 0;
423
424 num_tests += test_pages(&failures);
425 num_tests += test_kvmalloc(&failures);
426 num_tests += test_kmemcache(&failures);
427 num_tests += test_rcu_persistent(&failures);
428
429 if (failures == 0)
430 pr_info("all %d tests passed!\n", num_tests);
431 else
432 pr_info("failures: %d out of %d\n", failures, num_tests);
433
434 return failures ? -EINVAL : 0;
435}
436module_init(test_meminit_init);
437
438MODULE_DESCRIPTION("Test cases for SL[AOU]B/page initialization at alloc/free time");
439MODULE_LICENSE("GPL");