1 // SPDX-License-Identifier: GPL-2.0-or-later OR copyleft-next-0.3.1
2 /*
3 * kmod stress test driver
4 *
5 * Copyright (C) 2017 Luis R. Rodriguez <mcgrof@kernel.org>
6 */
7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9 /*
10 * This driver provides an interface to trigger and test the kernel's
11 * module loader through a series of configurations and a few triggers.
12 * To test this driver use the following script as root:
13 *
14 * tools/testing/selftests/kmod/kmod.sh --help
15 */
16
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/kmod.h>
20 #include <linux/printk.h>
21 #include <linux/kthread.h>
22 #include <linux/sched.h>
23 #include <linux/fs.h>
24 #include <linux/miscdevice.h>
25 #include <linux/vmalloc.h>
26 #include <linux/slab.h>
27 #include <linux/device.h>
28
29 #define TEST_START_NUM_THREADS 50
30 #define TEST_START_DRIVER "test_module"
31 #define TEST_START_TEST_FS "xfs"
32 #define TEST_START_TEST_CASE TEST_KMOD_DRIVER
33
34
35 static bool force_init_test = false;
36 module_param(force_init_test, bool_enable_only, 0644);
37 MODULE_PARM_DESC(force_init_test,
38 "Force kicking a test immediately after driver loads");
39
40 /*
41 * For device allocation / registration
42 */
43 static DEFINE_MUTEX(reg_dev_mutex);
44 static LIST_HEAD(reg_test_devs);
45
46 /*
47 * num_test_devs actually represents the *next* ID of the next
48 * device we will allow to create.
49 */
50 static int num_test_devs;
51
52 /**
53 * enum kmod_test_case - linker table test case
54 * @TEST_KMOD_DRIVER: stress tests request_module()
55 * @TEST_KMOD_FS_TYPE: stress tests get_fs_type()
56 *
57 * If you add a test case, please be sure to review if you need to set
58 * @need_mod_put for your tests case.
59 */
60 enum kmod_test_case {
61 /* private: */
62 __TEST_KMOD_INVALID = 0,
63 /* public: */
64
65 TEST_KMOD_DRIVER,
66 TEST_KMOD_FS_TYPE,
67
68 /* private: */
69 __TEST_KMOD_MAX,
70 };
71
72 struct test_config {
73 char *test_driver;
74 char *test_fs;
75 unsigned int num_threads;
76 enum kmod_test_case test_case;
77 int test_result;
78 };
79
80 struct kmod_test_device;
81
82 /**
83 * struct kmod_test_device_info - thread info
84 *
85 * @ret_sync: return value if request_module() is used, sync request for
86 * @TEST_KMOD_DRIVER
87 * @fs_sync: return value of get_fs_type() for @TEST_KMOD_FS_TYPE
88 * @task_sync: kthread's task_struct or %NULL if not running
89 * @thread_idx: thread ID
90 * @test_dev: test device test is being performed under
91 * @need_mod_put: Some tests (get_fs_type() is one) requires putting the module
92 * (module_put(fs_sync->owner)) when done, otherwise you will not be able
93 * to unload the respective modules and re-test. We use this to keep
94 * accounting of when we need this and to help out in case we need to
95 * error out and deal with module_put() on error.
96 */
97 struct kmod_test_device_info {
98 int ret_sync;
99 struct file_system_type *fs_sync;
100 struct task_struct *task_sync;
101 unsigned int thread_idx;
102 struct kmod_test_device *test_dev;
103 bool need_mod_put;
104 };
105
106 /**
107 * struct kmod_test_device - test device to help test kmod
108 *
109 * @dev_idx: unique ID for test device
110 * @config: configuration for the test
111 * @misc_dev: we use a misc device under the hood
112 * @dev: pointer to misc_dev's own struct device
113 * @config_mutex: protects configuration of test
114 * @trigger_mutex: the test trigger can only be fired once at a time
115 * @thread_mutex: protects @done count, and the @info per each thread
116 * @done: number of threads which have completed or failed
117 * @test_is_oom: when we run out of memory, use this to halt moving forward
118 * @kthreads_done: completion used to signal when all work is done
119 * @list: needed to be part of the reg_test_devs
120 * @info: array of info for each thread
121 */
122 struct kmod_test_device {
123 int dev_idx;
124 struct test_config config;
125 struct miscdevice misc_dev;
126 struct device *dev;
127 struct mutex config_mutex;
128 struct mutex trigger_mutex;
129 struct mutex thread_mutex;
130
131 unsigned int done;
132
133 bool test_is_oom;
134 struct completion kthreads_done;
135 struct list_head list;
136
137 struct kmod_test_device_info *info;
138 };
139
140 static const char *test_case_str(enum kmod_test_case test_case)
141 {
142 switch (test_case) {
143 case TEST_KMOD_DRIVER:
144 return "TEST_KMOD_DRIVER";
145 case TEST_KMOD_FS_TYPE:
146 return "TEST_KMOD_FS_TYPE";
147 default:
148 return "invalid";
149 }
150 }
151
152 static struct miscdevice *dev_to_misc_dev(struct device *dev)
153 {
154 return dev_get_drvdata(dev);
155 }
156
157 static struct kmod_test_device *misc_dev_to_test_dev(struct miscdevice *misc_dev)
158 {
159 return container_of(misc_dev, struct kmod_test_device, misc_dev);
160 }
161
162 static struct kmod_test_device *dev_to_test_dev(struct device *dev)
163 {
164 struct miscdevice *misc_dev;
165
166 misc_dev = dev_to_misc_dev(dev);
167
168 return misc_dev_to_test_dev(misc_dev);
169 }
170
171 /* Must run with thread_mutex held */
172 static void kmod_test_done_check(struct kmod_test_device *test_dev,
173 unsigned int idx)
174 {
175 struct test_config *config = &test_dev->config;
176
177 test_dev->done++;
178 dev_dbg(test_dev->dev, "Done thread count: %u\n", test_dev->done);
179
180 if (test_dev->done == config->num_threads) {
181 dev_info(test_dev->dev, "Done: %u threads have all run now\n",
182 test_dev->done);
183 dev_info(test_dev->dev, "Last thread to run: %u\n", idx);
184 complete(&test_dev->kthreads_done);
185 }
186 }
187
188 static void test_kmod_put_module(struct kmod_test_device_info *info)
189 {
190 struct kmod_test_device *test_dev = info->test_dev;
191 struct test_config *config = &test_dev->config;
192
193 if (!info->need_mod_put)
194 return;
195
196 switch (config->test_case) {
197 case TEST_KMOD_DRIVER:
198 break;
199 case TEST_KMOD_FS_TYPE:
200 if (info->fs_sync && info->fs_sync->owner)
201 module_put(info->fs_sync->owner);
202 break;
203 default:
204 BUG();
205 }
206
207 info->need_mod_put = true;
208 }
209
210 static int run_request(void *data)
211 {
212 struct kmod_test_device_info *info = data;
213 struct kmod_test_device *test_dev = info->test_dev;
214 struct test_config *config = &test_dev->config;
215
216 switch (config->test_case) {
217 case TEST_KMOD_DRIVER:
218 info->ret_sync = request_module("%s", config->test_driver);
219 break;
220 case TEST_KMOD_FS_TYPE:
221 info->fs_sync = get_fs_type(config->test_fs);
222 info->need_mod_put = true;
223 break;
224 default:
225 /* __trigger_config_run() already checked for test sanity */
226 BUG();
227 return -EINVAL;
228 }
229
230 dev_dbg(test_dev->dev, "Ran thread %u\n", info->thread_idx);
231
232 test_kmod_put_module(info);
233
234 mutex_lock(&test_dev->thread_mutex);
235 info->task_sync = NULL;
236 kmod_test_done_check(test_dev, info->thread_idx);
237 mutex_unlock(&test_dev->thread_mutex);
238
239 return 0;
240 }
241
242 static int tally_work_test(struct kmod_test_device_info *info)
243 {
244 struct kmod_test_device *test_dev = info->test_dev;
245 struct test_config *config = &test_dev->config;
246 int err_ret = 0;
247
248 switch (config->test_case) {
249 case TEST_KMOD_DRIVER:
250 /*
251 * Only capture errors, if one is found that's
252 * enough, for now.
253 */
254 if (info->ret_sync != 0)
255 err_ret = info->ret_sync;
256 dev_info(test_dev->dev,
257 "Sync thread %d return status: %d\n",
258 info->thread_idx, info->ret_sync);
259 break;
260 case TEST_KMOD_FS_TYPE:
261 /* For now we make this simple */
262 if (!info->fs_sync)
263 err_ret = -EINVAL;
264 dev_info(test_dev->dev, "Sync thread %u fs: %s\n",
265 info->thread_idx, info->fs_sync ? config->test_fs :
266 "NULL");
267 break;
268 default:
269 BUG();
270 }
271
272 return err_ret;
273 }
274
275 /*
276 * XXX: add result option to display if all errors did not match.
277 * For now we just keep any error code if one was found.
278 *
279 * If this ran it means *all* tasks were created fine and we
280 * are now just collecting results.
281 *
282 * Only propagate errors, do not override with a subsequent success case.
283 */
284 static void tally_up_work(struct kmod_test_device *test_dev)
285 {
286 struct test_config *config = &test_dev->config;
287 struct kmod_test_device_info *info;
288 unsigned int idx;
289 int err_ret = 0;
290 int ret = 0;
291
292 mutex_lock(&test_dev->thread_mutex);
293
294 dev_info(test_dev->dev, "Results:\n");
295
296 for (idx=0; idx < config->num_threads; idx++) {
297 info = &test_dev->info[idx];
298 ret = tally_work_test(info);
299 if (ret)
300 err_ret = ret;
301 }
302
303 /*
304 * Note: request_module() returns 256 for a module not found even
305 * though modprobe itself returns 1.
306 */
307 config->test_result = err_ret;
308
309 mutex_unlock(&test_dev->thread_mutex);
310 }
311
312 static int try_one_request(struct kmod_test_device *test_dev, unsigned int idx)
313 {
314 struct kmod_test_device_info *info = &test_dev->info[idx];
315 int fail_ret = -ENOMEM;
316
317 mutex_lock(&test_dev->thread_mutex);
318
319 info->thread_idx = idx;
320 info->test_dev = test_dev;
321 info->task_sync = kthread_run(run_request, info, "%s-%u",
322 KBUILD_MODNAME, idx);
323
324 if (!info->task_sync || IS_ERR(info->task_sync)) {
325 test_dev->test_is_oom = true;
326 dev_err(test_dev->dev, "Setting up thread %u failed\n", idx);
327 info->task_sync = NULL;
328 goto err_out;
329 } else
330 dev_dbg(test_dev->dev, "Kicked off thread %u\n", idx);
331
332 mutex_unlock(&test_dev->thread_mutex);
333
334 return 0;
335
336 err_out:
337 info->ret_sync = fail_ret;
338 mutex_unlock(&test_dev->thread_mutex);
339
340 return fail_ret;
341 }
342
343 static void test_dev_kmod_stop_tests(struct kmod_test_device *test_dev)
344 {
345 struct test_config *config = &test_dev->config;
346 struct kmod_test_device_info *info;
347 unsigned int i;
348
349 dev_info(test_dev->dev, "Ending request_module() tests\n");
350
351 mutex_lock(&test_dev->thread_mutex);
352
353 for (i=0; i < config->num_threads; i++) {
354 info = &test_dev->info[i];
355 if (info->task_sync && !IS_ERR(info->task_sync)) {
356 dev_info(test_dev->dev,
357 "Stopping still-running thread %i\n", i);
358 kthread_stop(info->task_sync);
359 }
360
361 /*
362 * info->task_sync is well protected, it can only be
363 * NULL or a pointer to a struct. If its NULL we either
364 * never ran, or we did and we completed the work. Completed
365 * tasks *always* put the module for us. This is a sanity
366 * check -- just in case.
367 */
368 if (info->task_sync && info->need_mod_put)
369 test_kmod_put_module(info);
370 }
371
372 mutex_unlock(&test_dev->thread_mutex);
373 }
374
375 /*
376 * Only wait *iff* we did not run into any errors during all of our thread
377 * set up. If run into any issues we stop threads and just bail out with
378 * an error to the trigger. This also means we don't need any tally work
379 * for any threads which fail.
380 */
381 static int try_requests(struct kmod_test_device *test_dev)
382 {
383 struct test_config *config = &test_dev->config;
384 unsigned int idx;
385 int ret;
386 bool any_error = false;
387
388 for (idx=0; idx < config->num_threads; idx++) {
389 if (test_dev->test_is_oom) {
390 any_error = true;
391 break;
392 }
393
394 ret = try_one_request(test_dev, idx);
395 if (ret) {
396 any_error = true;
397 break;
398 }
399 }
400
401 if (!any_error) {
402 test_dev->test_is_oom = false;
403 dev_info(test_dev->dev,
404 "No errors were found while initializing threads\n");
405 wait_for_completion(&test_dev->kthreads_done);
406 tally_up_work(test_dev);
407 } else {
408 test_dev->test_is_oom = true;
409 dev_info(test_dev->dev,
410 "At least one thread failed to start, stop all work\n");
411 test_dev_kmod_stop_tests(test_dev);
412 return -ENOMEM;
413 }
414
415 return 0;
416 }
417
418 static int run_test_driver(struct kmod_test_device *test_dev)
419 {
420 struct test_config *config = &test_dev->config;
421
422 dev_info(test_dev->dev, "Test case: %s (%u)\n",
423 test_case_str(config->test_case),
424 config->test_case);
425 dev_info(test_dev->dev, "Test driver to load: %s\n",
426 config->test_driver);
427 dev_info(test_dev->dev, "Number of threads to run: %u\n",
428 config->num_threads);
429 dev_info(test_dev->dev, "Thread IDs will range from 0 - %u\n",
430 config->num_threads - 1);
431
432 return try_requests(test_dev);
433 }
434
435 static int run_test_fs_type(struct kmod_test_device *test_dev)
436 {
437 struct test_config *config = &test_dev->config;
438
439 dev_info(test_dev->dev, "Test case: %s (%u)\n",
440 test_case_str(config->test_case),
441 config->test_case);
442 dev_info(test_dev->dev, "Test filesystem to load: %s\n",
443 config->test_fs);
444 dev_info(test_dev->dev, "Number of threads to run: %u\n",
445 config->num_threads);
446 dev_info(test_dev->dev, "Thread IDs will range from 0 - %u\n",
447 config->num_threads - 1);
448
449 return try_requests(test_dev);
450 }
451
452 static ssize_t config_show(struct device *dev,
453 struct device_attribute *attr,
454 char *buf)
455 {
456 struct kmod_test_device *test_dev = dev_to_test_dev(dev);
457 struct test_config *config = &test_dev->config;
458 int len = 0;
459
460 mutex_lock(&test_dev->config_mutex);
461
462 len += snprintf(buf, PAGE_SIZE,
463 "Custom trigger configuration for: %s\n",
464 dev_name(dev));
465
466 len += snprintf(buf+len, PAGE_SIZE - len,
467 "Number of threads:\t%u\n",
468 config->num_threads);
469
470 len += snprintf(buf+len, PAGE_SIZE - len,
471 "Test_case:\t%s (%u)\n",
472 test_case_str(config->test_case),
473 config->test_case);
474
475 if (config->test_driver)
476 len += snprintf(buf+len, PAGE_SIZE - len,
477 "driver:\t%s\n",
478 config->test_driver);
479 else
480 len += snprintf(buf+len, PAGE_SIZE - len,
481 "driver:\tEMPTY\n");
482
483 if (config->test_fs)
484 len += snprintf(buf+len, PAGE_SIZE - len,
485 "fs:\t%s\n",
486 config->test_fs);
487 else
488 len += snprintf(buf+len, PAGE_SIZE - len,
489 "fs:\tEMPTY\n");
490
491 mutex_unlock(&test_dev->config_mutex);
492
493 return len;
494 }
495 static DEVICE_ATTR_RO(config);
496
497 /*
498 * This ensures we don't allow kicking threads through if our configuration
499 * is faulty.
500 */
501 static int __trigger_config_run(struct kmod_test_device *test_dev)
502 {
503 struct test_config *config = &test_dev->config;
504
505 test_dev->done = 0;
506
507 switch (config->test_case) {
508 case TEST_KMOD_DRIVER:
509 return run_test_driver(test_dev);
510 case TEST_KMOD_FS_TYPE:
511 return run_test_fs_type(test_dev);
512 default:
513 dev_warn(test_dev->dev,
514 "Invalid test case requested: %u\n",
515 config->test_case);
516 return -EINVAL;
517 }
518 }
519
520 static int trigger_config_run(struct kmod_test_device *test_dev)
521 {
522 struct test_config *config = &test_dev->config;
523 int ret;
524
525 mutex_lock(&test_dev->trigger_mutex);
526 mutex_lock(&test_dev->config_mutex);
527
528 ret = __trigger_config_run(test_dev);
529 if (ret < 0)
530 goto out;
531 dev_info(test_dev->dev, "General test result: %d\n",
532 config->test_result);
533
534 /*
535 * We must return 0 after a trigger even unless something went
536 * wrong with the setup of the test. If the test setup went fine
537 * then userspace must just check the result of config->test_result.
538 * One issue with relying on the return from a call in the kernel
539 * is if the kernel returns a positive value using this trigger
540 * will not return the value to userspace, it would be lost.
541 *
542 * By not relying on capturing the return value of tests we are using
543 * through the trigger it also us to run tests with set -e and only
544 * fail when something went wrong with the driver upon trigger
545 * requests.
546 */
547 ret = 0;
548
549 out:
550 mutex_unlock(&test_dev->config_mutex);
551 mutex_unlock(&test_dev->trigger_mutex);
552
553 return ret;
554 }
555
556 static ssize_t
557 trigger_config_store(struct device *dev,
558 struct device_attribute *attr,
559 const char *buf, size_t count)
560 {
561 struct kmod_test_device *test_dev = dev_to_test_dev(dev);
562 int ret;
563
564 if (test_dev->test_is_oom)
565 return -ENOMEM;
566
567 /* For all intents and purposes we don't care what userspace
568 * sent this trigger, we care only that we were triggered.
569 * We treat the return value only for caputuring issues with
570 * the test setup. At this point all the test variables should
571 * have been allocated so typically this should never fail.
572 */
573 ret = trigger_config_run(test_dev);
574 if (unlikely(ret < 0))
575 goto out;
576
577 /*
578 * Note: any return > 0 will be treated as success
579 * and the error value will not be available to userspace.
580 * Do not rely on trying to send to userspace a test value
581 * return value as positive return errors will be lost.
582 */
583 if (WARN_ON(ret > 0))
584 return -EINVAL;
585
586 ret = count;
587 out:
588 return ret;
589 }
590 static DEVICE_ATTR_WO(trigger_config);
591
592 /*
593 * XXX: move to kstrncpy() once merged.
594 *
595 * Users should use kfree_const() when freeing these.
596 */
597 static int __kstrncpy(char **dst, const char *name, size_t count, gfp_t gfp)
598 {
599 *dst = kstrndup(name, count, gfp);
600 if (!*dst)
601 return -ENOSPC;
602 return count;
603 }
604
605 static int config_copy_test_driver_name(struct test_config *config,
606 const char *name,
607 size_t count)
608 {
609 return __kstrncpy(&config->test_driver, name, count, GFP_KERNEL);
610 }
611
612
613 static int config_copy_test_fs(struct test_config *config, const char *name,
614 size_t count)
615 {
616 return __kstrncpy(&config->test_fs, name, count, GFP_KERNEL);
617 }
618
619 static void __kmod_config_free(struct test_config *config)
620 {
621 if (!config)
622 return;
623
624 kfree_const(config->test_driver);
625 config->test_driver = NULL;
626
627 kfree_const(config->test_fs);
628 config->test_fs = NULL;
629 }
630
631 static void kmod_config_free(struct kmod_test_device *test_dev)
632 {
633 struct test_config *config;
634
635 if (!test_dev)
636 return;
637
638 config = &test_dev->config;
639
640 mutex_lock(&test_dev->config_mutex);
641 __kmod_config_free(config);
642 mutex_unlock(&test_dev->config_mutex);
643 }
644
645 static ssize_t config_test_driver_store(struct device *dev,
646 struct device_attribute *attr,
647 const char *buf, size_t count)
648 {
649 struct kmod_test_device *test_dev = dev_to_test_dev(dev);
650 struct test_config *config = &test_dev->config;
651 int copied;
652
653 mutex_lock(&test_dev->config_mutex);
654
655 kfree_const(config->test_driver);
656 config->test_driver = NULL;
657
658 copied = config_copy_test_driver_name(config, buf, count);
659 mutex_unlock(&test_dev->config_mutex);
660
661 return copied;
662 }
663
664 /*
665 * As per sysfs_kf_seq_show() the buf is max PAGE_SIZE.
666 */
667 static ssize_t config_test_show_str(struct mutex *config_mutex,
668 char *dst,
669 char *src)
670 {
671 int len;
672
673 mutex_lock(config_mutex);
674 len = snprintf(dst, PAGE_SIZE, "%s\n", src);
675 mutex_unlock(config_mutex);
676
677 return len;
678 }
679
680 static ssize_t config_test_driver_show(struct device *dev,
681 struct device_attribute *attr,
682 char *buf)
683 {
684 struct kmod_test_device *test_dev = dev_to_test_dev(dev);
685 struct test_config *config = &test_dev->config;
686
687 return config_test_show_str(&test_dev->config_mutex, buf,
688 config->test_driver);
689 }
690 static DEVICE_ATTR_RW(config_test_driver);
691
692 static ssize_t config_test_fs_store(struct device *dev,
693 struct device_attribute *attr,
694 const char *buf, size_t count)
695 {
696 struct kmod_test_device *test_dev = dev_to_test_dev(dev);
697 struct test_config *config = &test_dev->config;
698 int copied;
699
700 mutex_lock(&test_dev->config_mutex);
701
702 kfree_const(config->test_fs);
703 config->test_fs = NULL;
704
705 copied = config_copy_test_fs(config, buf, count);
706 mutex_unlock(&test_dev->config_mutex);
707
708 return copied;
709 }
710
711 static ssize_t config_test_fs_show(struct device *dev,
712 struct device_attribute *attr,
713 char *buf)
714 {
715 struct kmod_test_device *test_dev = dev_to_test_dev(dev);
716 struct test_config *config = &test_dev->config;
717
718 return config_test_show_str(&test_dev->config_mutex, buf,
719 config->test_fs);
720 }
721 static DEVICE_ATTR_RW(config_test_fs);
722
723 static int trigger_config_run_type(struct kmod_test_device *test_dev,
724 enum kmod_test_case test_case,
725 const char *test_str)
726 {
727 int copied = 0;
728 struct test_config *config = &test_dev->config;
729
730 mutex_lock(&test_dev->config_mutex);
731
732 switch (test_case) {
733 case TEST_KMOD_DRIVER:
734 kfree_const(config->test_driver);
735 config->test_driver = NULL;
736 copied = config_copy_test_driver_name(config, test_str,
737 strlen(test_str));
738 break;
739 case TEST_KMOD_FS_TYPE:
740 kfree_const(config->test_fs);
741 config->test_fs = NULL;
742 copied = config_copy_test_fs(config, test_str,
743 strlen(test_str));
744 break;
745 default:
746 mutex_unlock(&test_dev->config_mutex);
747 return -EINVAL;
748 }
749
750 config->test_case = test_case;
751
752 mutex_unlock(&test_dev->config_mutex);
753
754 if (copied <= 0 || copied != strlen(test_str)) {
755 test_dev->test_is_oom = true;
756 return -ENOMEM;
757 }
758
759 test_dev->test_is_oom = false;
760
761 return trigger_config_run(test_dev);
762 }
763
764 static void free_test_dev_info(struct kmod_test_device *test_dev)
765 {
766 vfree(test_dev->info);
767 test_dev->info = NULL;
768 }
769
770 static int kmod_config_sync_info(struct kmod_test_device *test_dev)
771 {
772 struct test_config *config = &test_dev->config;
773
774 free_test_dev_info(test_dev);
775 test_dev->info =
776 vzalloc(array_size(sizeof(struct kmod_test_device_info),
777 config->num_threads));
778 if (!test_dev->info)
779 return -ENOMEM;
780
781 return 0;
782 }
783
784 /*
785 * Old kernels may not have this, if you want to port this code to
786 * test it on older kernels.
787 */
788 #ifdef get_kmod_umh_limit
789 static unsigned int kmod_init_test_thread_limit(void)
790 {
791 return get_kmod_umh_limit();
792 }
793 #else
794 static unsigned int kmod_init_test_thread_limit(void)
795 {
796 return TEST_START_NUM_THREADS;
797 }
798 #endif
799
800 static int __kmod_config_init(struct kmod_test_device *test_dev)
801 {
802 struct test_config *config = &test_dev->config;
803 int ret = -ENOMEM, copied;
804
805 __kmod_config_free(config);
806
807 copied = config_copy_test_driver_name(config, TEST_START_DRIVER,
808 strlen(TEST_START_DRIVER));
809 if (copied != strlen(TEST_START_DRIVER))
810 goto err_out;
811
812 copied = config_copy_test_fs(config, TEST_START_TEST_FS,
813 strlen(TEST_START_TEST_FS));
814 if (copied != strlen(TEST_START_TEST_FS))
815 goto err_out;
816
817 config->num_threads = kmod_init_test_thread_limit();
818 config->test_result = 0;
819 config->test_case = TEST_START_TEST_CASE;
820
821 ret = kmod_config_sync_info(test_dev);
822 if (ret)
823 goto err_out;
824
825 test_dev->test_is_oom = false;
826
827 return 0;
828
829 err_out:
830 test_dev->test_is_oom = true;
831 WARN_ON(test_dev->test_is_oom);
832
833 __kmod_config_free(config);
834
835 return ret;
836 }
837
838 static ssize_t reset_store(struct device *dev,
839 struct device_attribute *attr,
840 const char *buf, size_t count)
841 {
842 struct kmod_test_device *test_dev = dev_to_test_dev(dev);
843 int ret;
844
845 mutex_lock(&test_dev->trigger_mutex);
846 mutex_lock(&test_dev->config_mutex);
847
848 ret = __kmod_config_init(test_dev);
849 if (ret < 0) {
850 ret = -ENOMEM;
851 dev_err(dev, "could not alloc settings for config trigger: %d\n",
852 ret);
853 goto out;
854 }
855
856 dev_info(dev, "reset\n");
857 ret = count;
858
859 out:
860 mutex_unlock(&test_dev->config_mutex);
861 mutex_unlock(&test_dev->trigger_mutex);
862
863 return ret;
864 }
865 static DEVICE_ATTR_WO(reset);
866
867 static int test_dev_config_update_uint_sync(struct kmod_test_device *test_dev,
868 const char *buf, size_t size,
869 unsigned int *config,
870 int (*test_sync)(struct kmod_test_device *test_dev))
871 {
872 int ret;
873 unsigned int val;
874 unsigned int old_val;
875
876 ret = kstrtouint(buf, 10, &val);
877 if (ret)
878 return ret;
879
880 mutex_lock(&test_dev->config_mutex);
881
882 old_val = *config;
883 *(unsigned int *)config = val;
884
885 ret = test_sync(test_dev);
886 if (ret) {
887 *(unsigned int *)config = old_val;
888
889 ret = test_sync(test_dev);
890 WARN_ON(ret);
891
892 mutex_unlock(&test_dev->config_mutex);
893 return -EINVAL;
894 }
895
896 mutex_unlock(&test_dev->config_mutex);
897 /* Always return full write size even if we didn't consume all */
898 return size;
899 }
900
901 static int test_dev_config_update_uint_range(struct kmod_test_device *test_dev,
902 const char *buf, size_t size,
903 unsigned int *config,
904 unsigned int min,
905 unsigned int max)
906 {
907 unsigned int val;
908 int ret;
909
910 ret = kstrtouint(buf, 10, &val);
911 if (ret)
912 return ret;
913
914 if (val < min || val > max)
915 return -EINVAL;
916
917 mutex_lock(&test_dev->config_mutex);
918 *config = val;
919 mutex_unlock(&test_dev->config_mutex);
920
921 /* Always return full write size even if we didn't consume all */
922 return size;
923 }
924
925 static int test_dev_config_update_int(struct kmod_test_device *test_dev,
926 const char *buf, size_t size,
927 int *config)
928 {
929 int val;
930 int ret;
931
932 ret = kstrtoint(buf, 10, &val);
933 if (ret)
934 return ret;
935
936 mutex_lock(&test_dev->config_mutex);
937 *config = val;
938 mutex_unlock(&test_dev->config_mutex);
939 /* Always return full write size even if we didn't consume all */
940 return size;
941 }
942
943 static ssize_t test_dev_config_show_int(struct kmod_test_device *test_dev,
944 char *buf,
945 int config)
946 {
947 int val;
948
949 mutex_lock(&test_dev->config_mutex);
950 val = config;
951 mutex_unlock(&test_dev->config_mutex);
952
953 return snprintf(buf, PAGE_SIZE, "%d\n", val);
954 }
955
956 static ssize_t test_dev_config_show_uint(struct kmod_test_device *test_dev,
957 char *buf,
958 unsigned int config)
959 {
960 unsigned int val;
961
962 mutex_lock(&test_dev->config_mutex);
963 val = config;
964 mutex_unlock(&test_dev->config_mutex);
965
966 return snprintf(buf, PAGE_SIZE, "%u\n", val);
967 }
968
969 static ssize_t test_result_store(struct device *dev,
970 struct device_attribute *attr,
971 const char *buf, size_t count)
972 {
973 struct kmod_test_device *test_dev = dev_to_test_dev(dev);
974 struct test_config *config = &test_dev->config;
975
976 return test_dev_config_update_int(test_dev, buf, count,
977 &config->test_result);
978 }
979
980 static ssize_t config_num_threads_store(struct device *dev,
981 struct device_attribute *attr,
982 const char *buf, size_t count)
983 {
984 struct kmod_test_device *test_dev = dev_to_test_dev(dev);
985 struct test_config *config = &test_dev->config;
986
987 return test_dev_config_update_uint_sync(test_dev, buf, count,
988 &config->num_threads,
989 kmod_config_sync_info);
990 }
991
992 static ssize_t config_num_threads_show(struct device *dev,
993 struct device_attribute *attr,
994 char *buf)
995 {
996 struct kmod_test_device *test_dev = dev_to_test_dev(dev);
997 struct test_config *config = &test_dev->config;
998
999 return test_dev_config_show_int(test_dev, buf, config->num_threads);
1000 }
1001 static DEVICE_ATTR_RW(config_num_threads);
1002
1003 static ssize_t config_test_case_store(struct device *dev,
1004 struct device_attribute *attr,
1005 const char *buf, size_t count)
1006 {
1007 struct kmod_test_device *test_dev = dev_to_test_dev(dev);
1008 struct test_config *config = &test_dev->config;
1009
1010 return test_dev_config_update_uint_range(test_dev, buf, count,
1011 &config->test_case,
1012 __TEST_KMOD_INVALID + 1,
1013 __TEST_KMOD_MAX - 1);
1014 }
1015
1016 static ssize_t config_test_case_show(struct device *dev,
1017 struct device_attribute *attr,
1018 char *buf)
1019 {
1020 struct kmod_test_device *test_dev = dev_to_test_dev(dev);
1021 struct test_config *config = &test_dev->config;
1022
1023 return test_dev_config_show_uint(test_dev, buf, config->test_case);
1024 }
1025 static DEVICE_ATTR_RW(config_test_case);
1026
1027 static ssize_t test_result_show(struct device *dev,
1028 struct device_attribute *attr,
1029 char *buf)
1030 {
1031 struct kmod_test_device *test_dev = dev_to_test_dev(dev);
1032 struct test_config *config = &test_dev->config;
1033
1034 return test_dev_config_show_int(test_dev, buf, config->test_result);
1035 }
1036 static DEVICE_ATTR_RW(test_result);
1037
1038 #define TEST_KMOD_DEV_ATTR(name) &dev_attr_##name.attr
1039
1040 static struct attribute *test_dev_attrs[] = {
1041 TEST_KMOD_DEV_ATTR(trigger_config),
1042 TEST_KMOD_DEV_ATTR(config),
1043 TEST_KMOD_DEV_ATTR(reset),
1044
1045 TEST_KMOD_DEV_ATTR(config_test_driver),
1046 TEST_KMOD_DEV_ATTR(config_test_fs),
1047 TEST_KMOD_DEV_ATTR(config_num_threads),
1048 TEST_KMOD_DEV_ATTR(config_test_case),
1049 TEST_KMOD_DEV_ATTR(test_result),
1050
1051 NULL,
1052 };
1053
1054 ATTRIBUTE_GROUPS(test_dev);
1055
1056 static int kmod_config_init(struct kmod_test_device *test_dev)
1057 {
1058 int ret;
1059
1060 mutex_lock(&test_dev->config_mutex);
1061 ret = __kmod_config_init(test_dev);
1062 mutex_unlock(&test_dev->config_mutex);
1063
1064 return ret;
1065 }
1066
1067 static struct kmod_test_device *alloc_test_dev_kmod(int idx)
1068 {
1069 int ret;
1070 struct kmod_test_device *test_dev;
1071 struct miscdevice *misc_dev;
1072
1073 test_dev = vzalloc(sizeof(struct kmod_test_device));
1074 if (!test_dev)
1075 goto err_out;
1076
1077 mutex_init(&test_dev->config_mutex);
1078 mutex_init(&test_dev->trigger_mutex);
1079 mutex_init(&test_dev->thread_mutex);
1080
1081 init_completion(&test_dev->kthreads_done);
1082
1083 ret = kmod_config_init(test_dev);
1084 if (ret < 0) {
1085 pr_err("Cannot alloc kmod_config_init()\n");
1086 goto err_out_free;
1087 }
1088
1089 test_dev->dev_idx = idx;
1090 misc_dev = &test_dev->misc_dev;
1091
1092 misc_dev->minor = MISC_DYNAMIC_MINOR;
1093 misc_dev->name = kasprintf(GFP_KERNEL, "test_kmod%d", idx);
1094 if (!misc_dev->name) {
1095 pr_err("Cannot alloc misc_dev->name\n");
1096 goto err_out_free_config;
1097 }
1098 misc_dev->groups = test_dev_groups;
1099
1100 return test_dev;
1101
1102 err_out_free_config:
1103 free_test_dev_info(test_dev);
1104 kmod_config_free(test_dev);
1105 err_out_free:
1106 vfree(test_dev);
1107 test_dev = NULL;
1108 err_out:
1109 return NULL;
1110 }
1111
1112 static void free_test_dev_kmod(struct kmod_test_device *test_dev)
1113 {
1114 if (test_dev) {
1115 kfree_const(test_dev->misc_dev.name);
1116 test_dev->misc_dev.name = NULL;
1117 free_test_dev_info(test_dev);
1118 kmod_config_free(test_dev);
1119 vfree(test_dev);
1120 test_dev = NULL;
1121 }
1122 }
1123
1124 static struct kmod_test_device *register_test_dev_kmod(void)
1125 {
1126 struct kmod_test_device *test_dev = NULL;
1127 int ret;
1128
1129 mutex_lock(®_dev_mutex);
1130
1131 /* int should suffice for number of devices, test for wrap */
1132 if (num_test_devs + 1 == INT_MAX) {
1133 pr_err("reached limit of number of test devices\n");
1134 goto out;
1135 }
1136
1137 test_dev = alloc_test_dev_kmod(num_test_devs);
1138 if (!test_dev)
1139 goto out;
1140
1141 ret = misc_register(&test_dev->misc_dev);
1142 if (ret) {
1143 pr_err("could not register misc device: %d\n", ret);
1144 free_test_dev_kmod(test_dev);
1145 test_dev = NULL;
1146 goto out;
1147 }
1148
1149 test_dev->dev = test_dev->misc_dev.this_device;
1150 list_add_tail(&test_dev->list, ®_test_devs);
1151 dev_info(test_dev->dev, "interface ready\n");
1152
1153 num_test_devs++;
1154
1155 out:
1156 mutex_unlock(®_dev_mutex);
1157
1158 return test_dev;
1159
1160 }
1161
1162 static int __init test_kmod_init(void)
1163 {
1164 struct kmod_test_device *test_dev;
1165 int ret;
1166
1167 test_dev = register_test_dev_kmod();
1168 if (!test_dev) {
1169 pr_err("Cannot add first test kmod device\n");
1170 return -ENODEV;
1171 }
1172
1173 /*
1174 * With some work we might be able to gracefully enable
1175 * testing with this driver built-in, for now this seems
1176 * rather risky. For those willing to try have at it,
1177 * and enable the below. Good luck! If that works, try
1178 * lowering the init level for more fun.
1179 */
1180 if (force_init_test) {
1181 ret = trigger_config_run_type(test_dev,
1182 TEST_KMOD_DRIVER, "tun");
1183 if (WARN_ON(ret))
1184 return ret;
1185 ret = trigger_config_run_type(test_dev,
1186 TEST_KMOD_FS_TYPE, "btrfs");
1187 if (WARN_ON(ret))
1188 return ret;
1189 }
1190
1191 return 0;
1192 }
1193 late_initcall(test_kmod_init);
1194
1195 static
1196 void unregister_test_dev_kmod(struct kmod_test_device *test_dev)
1197 {
1198 mutex_lock(&test_dev->trigger_mutex);
1199 mutex_lock(&test_dev->config_mutex);
1200
1201 test_dev_kmod_stop_tests(test_dev);
1202
1203 dev_info(test_dev->dev, "removing interface\n");
1204 misc_deregister(&test_dev->misc_dev);
1205
1206 mutex_unlock(&test_dev->config_mutex);
1207 mutex_unlock(&test_dev->trigger_mutex);
1208
1209 free_test_dev_kmod(test_dev);
1210 }
1211
1212 static void __exit test_kmod_exit(void)
1213 {
1214 struct kmod_test_device *test_dev, *tmp;
1215
1216 mutex_lock(®_dev_mutex);
1217 list_for_each_entry_safe(test_dev, tmp, ®_test_devs, list) {
1218 list_del(&test_dev->list);
1219 unregister_test_dev_kmod(test_dev);
1220 }
1221 mutex_unlock(®_dev_mutex);
1222 }
1223 module_exit(test_kmod_exit);
1224
1225 MODULE_AUTHOR("Luis R. Rodriguez <mcgrof@kernel.org>");
1226 MODULE_DESCRIPTION("kmod stress test driver");
1227 MODULE_LICENSE("GPL");
1228
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