1 /*
2  * kmod stress test driver
3  *
4  * Copyright (C) 2017 Luis R. Rodriguez <mcgrof@kernel.org>
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms of the GNU General Public License as published by the Free
8  * Software Foundation; either version 2 of the License, or at your option any
9  * later version; or, when distributed separately from the Linux kernel or
10  * when incorporated into other software packages, subject to the following
11  * license:
12  *
13  * This program is free software; you can redistribute it and/or modify it
14  * under the terms of copyleft-next (version 0.3.1 or later) as published
15  * at http://copyleft-next.org/.
16  */
17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18 
19 /*
20  * This driver provides an interface to trigger and test the kernel's
21  * module loader through a series of configurations and a few triggers.
22  * To test this driver use the following script as root:
23  *
24  * tools/testing/selftests/kmod/kmod.sh --help
25  */
26 
27 #include <linux/kernel.h>
28 #include <linux/module.h>
29 #include <linux/kmod.h>
30 #include <linux/printk.h>
31 #include <linux/kthread.h>
32 #include <linux/sched.h>
33 #include <linux/fs.h>
34 #include <linux/miscdevice.h>
35 #include <linux/vmalloc.h>
36 #include <linux/slab.h>
37 #include <linux/device.h>
38 
39 #define TEST_START_NUM_THREADS	50
40 #define TEST_START_DRIVER	"test_module"
41 #define TEST_START_TEST_FS	"xfs"
42 #define TEST_START_TEST_CASE	TEST_KMOD_DRIVER
43 
44 
45 static bool force_init_test = false;
46 module_param(force_init_test, bool_enable_only, 0644);
47 MODULE_PARM_DESC(force_init_test,
48 		 "Force kicking a test immediately after driver loads");
49 
50 /*
51  * For device allocation / registration
52  */
53 static DEFINE_MUTEX(reg_dev_mutex);
54 static LIST_HEAD(reg_test_devs);
55 
56 /*
57  * num_test_devs actually represents the *next* ID of the next
58  * device we will allow to create.
59  */
60 static int num_test_devs;
61 
62 /**
63  * enum kmod_test_case - linker table test case
64  *
65  * If you add a  test case, please be sure to review if you need to se
66  * @need_mod_put for your tests case.
67  *
68  * @TEST_KMOD_DRIVER: stress tests request_module()
69  * @TEST_KMOD_FS_TYPE: stress tests get_fs_type()
70  */
71 enum kmod_test_case {
72 	__TEST_KMOD_INVALID = 0,
73 
74 	TEST_KMOD_DRIVER,
75 	TEST_KMOD_FS_TYPE,
76 
77 	__TEST_KMOD_MAX,
78 };
79 
80 struct test_config {
81 	char *test_driver;
82 	char *test_fs;
83 	unsigned int num_threads;
84 	enum kmod_test_case test_case;
85 	int test_result;
86 };
87 
88 struct kmod_test_device;
89 
90 /**
91  * kmod_test_device_info - thread info
92  *
93  * @ret_sync: return value if request_module() is used, sync request for
94  * 	@TEST_KMOD_DRIVER
95  * @fs_sync: return value of get_fs_type() for @TEST_KMOD_FS_TYPE
96  * @thread_idx: thread ID
97  * @test_dev: test device test is being performed under
98  * @need_mod_put: Some tests (get_fs_type() is one) requires putting the module
99  *	(module_put(fs_sync->owner)) when done, otherwise you will not be able
100  *	to unload the respective modules and re-test. We use this to keep
101  *	accounting of when we need this and to help out in case we need to
102  *	error out and deal with module_put() on error.
103  */
104 struct kmod_test_device_info {
105 	int ret_sync;
106 	struct file_system_type *fs_sync;
107 	struct task_struct *task_sync;
108 	unsigned int thread_idx;
109 	struct kmod_test_device *test_dev;
110 	bool need_mod_put;
111 };
112 
113 /**
114  * kmod_test_device - test device to help test kmod
115  *
116  * @dev_idx: unique ID for test device
117  * @config: configuration for the test
118  * @misc_dev: we use a misc device under the hood
119  * @dev: pointer to misc_dev's own struct device
120  * @config_mutex: protects configuration of test
121  * @trigger_mutex: the test trigger can only be fired once at a time
122  * @thread_lock: protects @done count, and the @info per each thread
123  * @done: number of threads which have completed or failed
124  * @test_is_oom: when we run out of memory, use this to halt moving forward
125  * @kthreads_done: completion used to signal when all work is done
126  * @list: needed to be part of the reg_test_devs
127  * @info: array of info for each thread
128  */
129 struct kmod_test_device {
130 	int dev_idx;
131 	struct test_config config;
132 	struct miscdevice misc_dev;
133 	struct device *dev;
134 	struct mutex config_mutex;
135 	struct mutex trigger_mutex;
136 	struct mutex thread_mutex;
137 
138 	unsigned int done;
139 
140 	bool test_is_oom;
141 	struct completion kthreads_done;
142 	struct list_head list;
143 
144 	struct kmod_test_device_info *info;
145 };
146 
test_case_str(enum kmod_test_case test_case)147 static const char *test_case_str(enum kmod_test_case test_case)
148 {
149 	switch (test_case) {
150 	case TEST_KMOD_DRIVER:
151 		return "TEST_KMOD_DRIVER";
152 	case TEST_KMOD_FS_TYPE:
153 		return "TEST_KMOD_FS_TYPE";
154 	default:
155 		return "invalid";
156 	}
157 }
158 
dev_to_misc_dev(struct device * dev)159 static struct miscdevice *dev_to_misc_dev(struct device *dev)
160 {
161 	return dev_get_drvdata(dev);
162 }
163 
misc_dev_to_test_dev(struct miscdevice * misc_dev)164 static struct kmod_test_device *misc_dev_to_test_dev(struct miscdevice *misc_dev)
165 {
166 	return container_of(misc_dev, struct kmod_test_device, misc_dev);
167 }
168 
dev_to_test_dev(struct device * dev)169 static struct kmod_test_device *dev_to_test_dev(struct device *dev)
170 {
171 	struct miscdevice *misc_dev;
172 
173 	misc_dev = dev_to_misc_dev(dev);
174 
175 	return misc_dev_to_test_dev(misc_dev);
176 }
177 
178 /* Must run with thread_mutex held */
kmod_test_done_check(struct kmod_test_device * test_dev,unsigned int idx)179 static void kmod_test_done_check(struct kmod_test_device *test_dev,
180 				 unsigned int idx)
181 {
182 	struct test_config *config = &test_dev->config;
183 
184 	test_dev->done++;
185 	dev_dbg(test_dev->dev, "Done thread count: %u\n", test_dev->done);
186 
187 	if (test_dev->done == config->num_threads) {
188 		dev_info(test_dev->dev, "Done: %u threads have all run now\n",
189 			 test_dev->done);
190 		dev_info(test_dev->dev, "Last thread to run: %u\n", idx);
191 		complete(&test_dev->kthreads_done);
192 	}
193 }
194 
test_kmod_put_module(struct kmod_test_device_info * info)195 static void test_kmod_put_module(struct kmod_test_device_info *info)
196 {
197 	struct kmod_test_device *test_dev = info->test_dev;
198 	struct test_config *config = &test_dev->config;
199 
200 	if (!info->need_mod_put)
201 		return;
202 
203 	switch (config->test_case) {
204 	case TEST_KMOD_DRIVER:
205 		break;
206 	case TEST_KMOD_FS_TYPE:
207 		if (info->fs_sync && info->fs_sync->owner)
208 			module_put(info->fs_sync->owner);
209 		break;
210 	default:
211 		BUG();
212 	}
213 
214 	info->need_mod_put = true;
215 }
216 
run_request(void * data)217 static int run_request(void *data)
218 {
219 	struct kmod_test_device_info *info = data;
220 	struct kmod_test_device *test_dev = info->test_dev;
221 	struct test_config *config = &test_dev->config;
222 
223 	switch (config->test_case) {
224 	case TEST_KMOD_DRIVER:
225 		info->ret_sync = request_module("%s", config->test_driver);
226 		break;
227 	case TEST_KMOD_FS_TYPE:
228 		info->fs_sync = get_fs_type(config->test_fs);
229 		info->need_mod_put = true;
230 		break;
231 	default:
232 		/* __trigger_config_run() already checked for test sanity */
233 		BUG();
234 		return -EINVAL;
235 	}
236 
237 	dev_dbg(test_dev->dev, "Ran thread %u\n", info->thread_idx);
238 
239 	test_kmod_put_module(info);
240 
241 	mutex_lock(&test_dev->thread_mutex);
242 	info->task_sync = NULL;
243 	kmod_test_done_check(test_dev, info->thread_idx);
244 	mutex_unlock(&test_dev->thread_mutex);
245 
246 	return 0;
247 }
248 
tally_work_test(struct kmod_test_device_info * info)249 static int tally_work_test(struct kmod_test_device_info *info)
250 {
251 	struct kmod_test_device *test_dev = info->test_dev;
252 	struct test_config *config = &test_dev->config;
253 	int err_ret = 0;
254 
255 	switch (config->test_case) {
256 	case TEST_KMOD_DRIVER:
257 		/*
258 		 * Only capture errors, if one is found that's
259 		 * enough, for now.
260 		 */
261 		if (info->ret_sync != 0)
262 			err_ret = info->ret_sync;
263 		dev_info(test_dev->dev,
264 			 "Sync thread %d return status: %d\n",
265 			 info->thread_idx, info->ret_sync);
266 		break;
267 	case TEST_KMOD_FS_TYPE:
268 		/* For now we make this simple */
269 		if (!info->fs_sync)
270 			err_ret = -EINVAL;
271 		dev_info(test_dev->dev, "Sync thread %u fs: %s\n",
272 			 info->thread_idx, info->fs_sync ? config->test_fs :
273 			 "NULL");
274 		break;
275 	default:
276 		BUG();
277 	}
278 
279 	return err_ret;
280 }
281 
282 /*
283  * XXX: add result option to display if all errors did not match.
284  * For now we just keep any error code if one was found.
285  *
286  * If this ran it means *all* tasks were created fine and we
287  * are now just collecting results.
288  *
289  * Only propagate errors, do not override with a subsequent success case.
290  */
tally_up_work(struct kmod_test_device * test_dev)291 static void tally_up_work(struct kmod_test_device *test_dev)
292 {
293 	struct test_config *config = &test_dev->config;
294 	struct kmod_test_device_info *info;
295 	unsigned int idx;
296 	int err_ret = 0;
297 	int ret = 0;
298 
299 	mutex_lock(&test_dev->thread_mutex);
300 
301 	dev_info(test_dev->dev, "Results:\n");
302 
303 	for (idx=0; idx < config->num_threads; idx++) {
304 		info = &test_dev->info[idx];
305 		ret = tally_work_test(info);
306 		if (ret)
307 			err_ret = ret;
308 	}
309 
310 	/*
311 	 * Note: request_module() returns 256 for a module not found even
312 	 * though modprobe itself returns 1.
313 	 */
314 	config->test_result = err_ret;
315 
316 	mutex_unlock(&test_dev->thread_mutex);
317 }
318 
try_one_request(struct kmod_test_device * test_dev,unsigned int idx)319 static int try_one_request(struct kmod_test_device *test_dev, unsigned int idx)
320 {
321 	struct kmod_test_device_info *info = &test_dev->info[idx];
322 	int fail_ret = -ENOMEM;
323 
324 	mutex_lock(&test_dev->thread_mutex);
325 
326 	info->thread_idx = idx;
327 	info->test_dev = test_dev;
328 	info->task_sync = kthread_run(run_request, info, "%s-%u",
329 				      KBUILD_MODNAME, idx);
330 
331 	if (!info->task_sync || IS_ERR(info->task_sync)) {
332 		test_dev->test_is_oom = true;
333 		dev_err(test_dev->dev, "Setting up thread %u failed\n", idx);
334 		info->task_sync = NULL;
335 		goto err_out;
336 	} else
337 		dev_dbg(test_dev->dev, "Kicked off thread %u\n", idx);
338 
339 	mutex_unlock(&test_dev->thread_mutex);
340 
341 	return 0;
342 
343 err_out:
344 	info->ret_sync = fail_ret;
345 	mutex_unlock(&test_dev->thread_mutex);
346 
347 	return fail_ret;
348 }
349 
test_dev_kmod_stop_tests(struct kmod_test_device * test_dev)350 static void test_dev_kmod_stop_tests(struct kmod_test_device *test_dev)
351 {
352 	struct test_config *config = &test_dev->config;
353 	struct kmod_test_device_info *info;
354 	unsigned int i;
355 
356 	dev_info(test_dev->dev, "Ending request_module() tests\n");
357 
358 	mutex_lock(&test_dev->thread_mutex);
359 
360 	for (i=0; i < config->num_threads; i++) {
361 		info = &test_dev->info[i];
362 		if (info->task_sync && !IS_ERR(info->task_sync)) {
363 			dev_info(test_dev->dev,
364 				 "Stopping still-running thread %i\n", i);
365 			kthread_stop(info->task_sync);
366 		}
367 
368 		/*
369 		 * info->task_sync is well protected, it can only be
370 		 * NULL or a pointer to a struct. If its NULL we either
371 		 * never ran, or we did and we completed the work. Completed
372 		 * tasks *always* put the module for us. This is a sanity
373 		 * check -- just in case.
374 		 */
375 		if (info->task_sync && info->need_mod_put)
376 			test_kmod_put_module(info);
377 	}
378 
379 	mutex_unlock(&test_dev->thread_mutex);
380 }
381 
382 /*
383  * Only wait *iff* we did not run into any errors during all of our thread
384  * set up. If run into any issues we stop threads and just bail out with
385  * an error to the trigger. This also means we don't need any tally work
386  * for any threads which fail.
387  */
try_requests(struct kmod_test_device * test_dev)388 static int try_requests(struct kmod_test_device *test_dev)
389 {
390 	struct test_config *config = &test_dev->config;
391 	unsigned int idx;
392 	int ret;
393 	bool any_error = false;
394 
395 	for (idx=0; idx < config->num_threads; idx++) {
396 		if (test_dev->test_is_oom) {
397 			any_error = true;
398 			break;
399 		}
400 
401 		ret = try_one_request(test_dev, idx);
402 		if (ret) {
403 			any_error = true;
404 			break;
405 		}
406 	}
407 
408 	if (!any_error) {
409 		test_dev->test_is_oom = false;
410 		dev_info(test_dev->dev,
411 			 "No errors were found while initializing threads\n");
412 		wait_for_completion(&test_dev->kthreads_done);
413 		tally_up_work(test_dev);
414 	} else {
415 		test_dev->test_is_oom = true;
416 		dev_info(test_dev->dev,
417 			 "At least one thread failed to start, stop all work\n");
418 		test_dev_kmod_stop_tests(test_dev);
419 		return -ENOMEM;
420 	}
421 
422 	return 0;
423 }
424 
run_test_driver(struct kmod_test_device * test_dev)425 static int run_test_driver(struct kmod_test_device *test_dev)
426 {
427 	struct test_config *config = &test_dev->config;
428 
429 	dev_info(test_dev->dev, "Test case: %s (%u)\n",
430 		 test_case_str(config->test_case),
431 		 config->test_case);
432 	dev_info(test_dev->dev, "Test driver to load: %s\n",
433 		 config->test_driver);
434 	dev_info(test_dev->dev, "Number of threads to run: %u\n",
435 		 config->num_threads);
436 	dev_info(test_dev->dev, "Thread IDs will range from 0 - %u\n",
437 		 config->num_threads - 1);
438 
439 	return try_requests(test_dev);
440 }
441 
run_test_fs_type(struct kmod_test_device * test_dev)442 static int run_test_fs_type(struct kmod_test_device *test_dev)
443 {
444 	struct test_config *config = &test_dev->config;
445 
446 	dev_info(test_dev->dev, "Test case: %s (%u)\n",
447 		 test_case_str(config->test_case),
448 		 config->test_case);
449 	dev_info(test_dev->dev, "Test filesystem to load: %s\n",
450 		 config->test_fs);
451 	dev_info(test_dev->dev, "Number of threads to run: %u\n",
452 		 config->num_threads);
453 	dev_info(test_dev->dev, "Thread IDs will range from 0 - %u\n",
454 		 config->num_threads - 1);
455 
456 	return try_requests(test_dev);
457 }
458 
config_show(struct device * dev,struct device_attribute * attr,char * buf)459 static ssize_t config_show(struct device *dev,
460 			   struct device_attribute *attr,
461 			   char *buf)
462 {
463 	struct kmod_test_device *test_dev = dev_to_test_dev(dev);
464 	struct test_config *config = &test_dev->config;
465 	int len = 0;
466 
467 	mutex_lock(&test_dev->config_mutex);
468 
469 	len += snprintf(buf, PAGE_SIZE,
470 			"Custom trigger configuration for: %s\n",
471 			dev_name(dev));
472 
473 	len += snprintf(buf+len, PAGE_SIZE - len,
474 			"Number of threads:\t%u\n",
475 			config->num_threads);
476 
477 	len += snprintf(buf+len, PAGE_SIZE - len,
478 			"Test_case:\t%s (%u)\n",
479 			test_case_str(config->test_case),
480 			config->test_case);
481 
482 	if (config->test_driver)
483 		len += snprintf(buf+len, PAGE_SIZE - len,
484 				"driver:\t%s\n",
485 				config->test_driver);
486 	else
487 		len += snprintf(buf+len, PAGE_SIZE - len,
488 				"driver:\tEMPTY\n");
489 
490 	if (config->test_fs)
491 		len += snprintf(buf+len, PAGE_SIZE - len,
492 				"fs:\t%s\n",
493 				config->test_fs);
494 	else
495 		len += snprintf(buf+len, PAGE_SIZE - len,
496 				"fs:\tEMPTY\n");
497 
498 	mutex_unlock(&test_dev->config_mutex);
499 
500 	return len;
501 }
502 static DEVICE_ATTR_RO(config);
503 
504 /*
505  * This ensures we don't allow kicking threads through if our configuration
506  * is faulty.
507  */
__trigger_config_run(struct kmod_test_device * test_dev)508 static int __trigger_config_run(struct kmod_test_device *test_dev)
509 {
510 	struct test_config *config = &test_dev->config;
511 
512 	test_dev->done = 0;
513 
514 	switch (config->test_case) {
515 	case TEST_KMOD_DRIVER:
516 		return run_test_driver(test_dev);
517 	case TEST_KMOD_FS_TYPE:
518 		return run_test_fs_type(test_dev);
519 	default:
520 		dev_warn(test_dev->dev,
521 			 "Invalid test case requested: %u\n",
522 			 config->test_case);
523 		return -EINVAL;
524 	}
525 }
526 
trigger_config_run(struct kmod_test_device * test_dev)527 static int trigger_config_run(struct kmod_test_device *test_dev)
528 {
529 	struct test_config *config = &test_dev->config;
530 	int ret;
531 
532 	mutex_lock(&test_dev->trigger_mutex);
533 	mutex_lock(&test_dev->config_mutex);
534 
535 	ret = __trigger_config_run(test_dev);
536 	if (ret < 0)
537 		goto out;
538 	dev_info(test_dev->dev, "General test result: %d\n",
539 		 config->test_result);
540 
541 	/*
542 	 * We must return 0 after a trigger even unless something went
543 	 * wrong with the setup of the test. If the test setup went fine
544 	 * then userspace must just check the result of config->test_result.
545 	 * One issue with relying on the return from a call in the kernel
546 	 * is if the kernel returns a positive value using this trigger
547 	 * will not return the value to userspace, it would be lost.
548 	 *
549 	 * By not relying on capturing the return value of tests we are using
550 	 * through the trigger it also us to run tests with set -e and only
551 	 * fail when something went wrong with the driver upon trigger
552 	 * requests.
553 	 */
554 	ret = 0;
555 
556 out:
557 	mutex_unlock(&test_dev->config_mutex);
558 	mutex_unlock(&test_dev->trigger_mutex);
559 
560 	return ret;
561 }
562 
563 static ssize_t
trigger_config_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)564 trigger_config_store(struct device *dev,
565 		     struct device_attribute *attr,
566 		     const char *buf, size_t count)
567 {
568 	struct kmod_test_device *test_dev = dev_to_test_dev(dev);
569 	int ret;
570 
571 	if (test_dev->test_is_oom)
572 		return -ENOMEM;
573 
574 	/* For all intents and purposes we don't care what userspace
575 	 * sent this trigger, we care only that we were triggered.
576 	 * We treat the return value only for caputuring issues with
577 	 * the test setup. At this point all the test variables should
578 	 * have been allocated so typically this should never fail.
579 	 */
580 	ret = trigger_config_run(test_dev);
581 	if (unlikely(ret < 0))
582 		goto out;
583 
584 	/*
585 	 * Note: any return > 0 will be treated as success
586 	 * and the error value will not be available to userspace.
587 	 * Do not rely on trying to send to userspace a test value
588 	 * return value as positive return errors will be lost.
589 	 */
590 	if (WARN_ON(ret > 0))
591 		return -EINVAL;
592 
593 	ret = count;
594 out:
595 	return ret;
596 }
597 static DEVICE_ATTR_WO(trigger_config);
598 
599 /*
600  * XXX: move to kstrncpy() once merged.
601  *
602  * Users should use kfree_const() when freeing these.
603  */
__kstrncpy(char ** dst,const char * name,size_t count,gfp_t gfp)604 static int __kstrncpy(char **dst, const char *name, size_t count, gfp_t gfp)
605 {
606 	*dst = kstrndup(name, count, gfp);
607 	if (!*dst)
608 		return -ENOSPC;
609 	return count;
610 }
611 
config_copy_test_driver_name(struct test_config * config,const char * name,size_t count)612 static int config_copy_test_driver_name(struct test_config *config,
613 				    const char *name,
614 				    size_t count)
615 {
616 	return __kstrncpy(&config->test_driver, name, count, GFP_KERNEL);
617 }
618 
619 
config_copy_test_fs(struct test_config * config,const char * name,size_t count)620 static int config_copy_test_fs(struct test_config *config, const char *name,
621 			       size_t count)
622 {
623 	return __kstrncpy(&config->test_fs, name, count, GFP_KERNEL);
624 }
625 
__kmod_config_free(struct test_config * config)626 static void __kmod_config_free(struct test_config *config)
627 {
628 	if (!config)
629 		return;
630 
631 	kfree_const(config->test_driver);
632 	config->test_driver = NULL;
633 
634 	kfree_const(config->test_fs);
635 	config->test_fs = NULL;
636 }
637 
kmod_config_free(struct kmod_test_device * test_dev)638 static void kmod_config_free(struct kmod_test_device *test_dev)
639 {
640 	struct test_config *config;
641 
642 	if (!test_dev)
643 		return;
644 
645 	config = &test_dev->config;
646 
647 	mutex_lock(&test_dev->config_mutex);
648 	__kmod_config_free(config);
649 	mutex_unlock(&test_dev->config_mutex);
650 }
651 
config_test_driver_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)652 static ssize_t config_test_driver_store(struct device *dev,
653 					struct device_attribute *attr,
654 					const char *buf, size_t count)
655 {
656 	struct kmod_test_device *test_dev = dev_to_test_dev(dev);
657 	struct test_config *config = &test_dev->config;
658 	int copied;
659 
660 	mutex_lock(&test_dev->config_mutex);
661 
662 	kfree_const(config->test_driver);
663 	config->test_driver = NULL;
664 
665 	copied = config_copy_test_driver_name(config, buf, count);
666 	mutex_unlock(&test_dev->config_mutex);
667 
668 	return copied;
669 }
670 
671 /*
672  * As per sysfs_kf_seq_show() the buf is max PAGE_SIZE.
673  */
config_test_show_str(struct mutex * config_mutex,char * dst,char * src)674 static ssize_t config_test_show_str(struct mutex *config_mutex,
675 				    char *dst,
676 				    char *src)
677 {
678 	int len;
679 
680 	mutex_lock(config_mutex);
681 	len = snprintf(dst, PAGE_SIZE, "%s\n", src);
682 	mutex_unlock(config_mutex);
683 
684 	return len;
685 }
686 
config_test_driver_show(struct device * dev,struct device_attribute * attr,char * buf)687 static ssize_t config_test_driver_show(struct device *dev,
688 					struct device_attribute *attr,
689 					char *buf)
690 {
691 	struct kmod_test_device *test_dev = dev_to_test_dev(dev);
692 	struct test_config *config = &test_dev->config;
693 
694 	return config_test_show_str(&test_dev->config_mutex, buf,
695 				    config->test_driver);
696 }
697 static DEVICE_ATTR_RW(config_test_driver);
698 
config_test_fs_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)699 static ssize_t config_test_fs_store(struct device *dev,
700 				    struct device_attribute *attr,
701 				    const char *buf, size_t count)
702 {
703 	struct kmod_test_device *test_dev = dev_to_test_dev(dev);
704 	struct test_config *config = &test_dev->config;
705 	int copied;
706 
707 	mutex_lock(&test_dev->config_mutex);
708 
709 	kfree_const(config->test_fs);
710 	config->test_fs = NULL;
711 
712 	copied = config_copy_test_fs(config, buf, count);
713 	mutex_unlock(&test_dev->config_mutex);
714 
715 	return copied;
716 }
717 
config_test_fs_show(struct device * dev,struct device_attribute * attr,char * buf)718 static ssize_t config_test_fs_show(struct device *dev,
719 				   struct device_attribute *attr,
720 				   char *buf)
721 {
722 	struct kmod_test_device *test_dev = dev_to_test_dev(dev);
723 	struct test_config *config = &test_dev->config;
724 
725 	return config_test_show_str(&test_dev->config_mutex, buf,
726 				    config->test_fs);
727 }
728 static DEVICE_ATTR_RW(config_test_fs);
729 
trigger_config_run_type(struct kmod_test_device * test_dev,enum kmod_test_case test_case,const char * test_str)730 static int trigger_config_run_type(struct kmod_test_device *test_dev,
731 				   enum kmod_test_case test_case,
732 				   const char *test_str)
733 {
734 	int copied = 0;
735 	struct test_config *config = &test_dev->config;
736 
737 	mutex_lock(&test_dev->config_mutex);
738 
739 	switch (test_case) {
740 	case TEST_KMOD_DRIVER:
741 		kfree_const(config->test_driver);
742 		config->test_driver = NULL;
743 		copied = config_copy_test_driver_name(config, test_str,
744 						      strlen(test_str));
745 		break;
746 	case TEST_KMOD_FS_TYPE:
747 		kfree_const(config->test_fs);
748 		config->test_fs = NULL;
749 		copied = config_copy_test_fs(config, test_str,
750 					     strlen(test_str));
751 		break;
752 	default:
753 		mutex_unlock(&test_dev->config_mutex);
754 		return -EINVAL;
755 	}
756 
757 	config->test_case = test_case;
758 
759 	mutex_unlock(&test_dev->config_mutex);
760 
761 	if (copied <= 0 || copied != strlen(test_str)) {
762 		test_dev->test_is_oom = true;
763 		return -ENOMEM;
764 	}
765 
766 	test_dev->test_is_oom = false;
767 
768 	return trigger_config_run(test_dev);
769 }
770 
free_test_dev_info(struct kmod_test_device * test_dev)771 static void free_test_dev_info(struct kmod_test_device *test_dev)
772 {
773 	vfree(test_dev->info);
774 	test_dev->info = NULL;
775 }
776 
kmod_config_sync_info(struct kmod_test_device * test_dev)777 static int kmod_config_sync_info(struct kmod_test_device *test_dev)
778 {
779 	struct test_config *config = &test_dev->config;
780 
781 	free_test_dev_info(test_dev);
782 	test_dev->info =
783 		vzalloc(array_size(sizeof(struct kmod_test_device_info),
784 				   config->num_threads));
785 	if (!test_dev->info)
786 		return -ENOMEM;
787 
788 	return 0;
789 }
790 
791 /*
792  * Old kernels may not have this, if you want to port this code to
793  * test it on older kernels.
794  */
795 #ifdef get_kmod_umh_limit
kmod_init_test_thread_limit(void)796 static unsigned int kmod_init_test_thread_limit(void)
797 {
798 	return get_kmod_umh_limit();
799 }
800 #else
kmod_init_test_thread_limit(void)801 static unsigned int kmod_init_test_thread_limit(void)
802 {
803 	return TEST_START_NUM_THREADS;
804 }
805 #endif
806 
__kmod_config_init(struct kmod_test_device * test_dev)807 static int __kmod_config_init(struct kmod_test_device *test_dev)
808 {
809 	struct test_config *config = &test_dev->config;
810 	int ret = -ENOMEM, copied;
811 
812 	__kmod_config_free(config);
813 
814 	copied = config_copy_test_driver_name(config, TEST_START_DRIVER,
815 					      strlen(TEST_START_DRIVER));
816 	if (copied != strlen(TEST_START_DRIVER))
817 		goto err_out;
818 
819 	copied = config_copy_test_fs(config, TEST_START_TEST_FS,
820 				     strlen(TEST_START_TEST_FS));
821 	if (copied != strlen(TEST_START_TEST_FS))
822 		goto err_out;
823 
824 	config->num_threads = kmod_init_test_thread_limit();
825 	config->test_result = 0;
826 	config->test_case = TEST_START_TEST_CASE;
827 
828 	ret = kmod_config_sync_info(test_dev);
829 	if (ret)
830 		goto err_out;
831 
832 	test_dev->test_is_oom = false;
833 
834 	return 0;
835 
836 err_out:
837 	test_dev->test_is_oom = true;
838 	WARN_ON(test_dev->test_is_oom);
839 
840 	__kmod_config_free(config);
841 
842 	return ret;
843 }
844 
reset_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)845 static ssize_t reset_store(struct device *dev,
846 			   struct device_attribute *attr,
847 			   const char *buf, size_t count)
848 {
849 	struct kmod_test_device *test_dev = dev_to_test_dev(dev);
850 	int ret;
851 
852 	mutex_lock(&test_dev->trigger_mutex);
853 	mutex_lock(&test_dev->config_mutex);
854 
855 	ret = __kmod_config_init(test_dev);
856 	if (ret < 0) {
857 		ret = -ENOMEM;
858 		dev_err(dev, "could not alloc settings for config trigger: %d\n",
859 		       ret);
860 		goto out;
861 	}
862 
863 	dev_info(dev, "reset\n");
864 	ret = count;
865 
866 out:
867 	mutex_unlock(&test_dev->config_mutex);
868 	mutex_unlock(&test_dev->trigger_mutex);
869 
870 	return ret;
871 }
872 static DEVICE_ATTR_WO(reset);
873 
test_dev_config_update_uint_sync(struct kmod_test_device * test_dev,const char * buf,size_t size,unsigned int * config,int (* test_sync)(struct kmod_test_device * test_dev))874 static int test_dev_config_update_uint_sync(struct kmod_test_device *test_dev,
875 					    const char *buf, size_t size,
876 					    unsigned int *config,
877 					    int (*test_sync)(struct kmod_test_device *test_dev))
878 {
879 	int ret;
880 	unsigned int val;
881 	unsigned int old_val;
882 
883 	ret = kstrtouint(buf, 10, &val);
884 	if (ret)
885 		return ret;
886 
887 	mutex_lock(&test_dev->config_mutex);
888 
889 	old_val = *config;
890 	*(unsigned int *)config = val;
891 
892 	ret = test_sync(test_dev);
893 	if (ret) {
894 		*(unsigned int *)config = old_val;
895 
896 		ret = test_sync(test_dev);
897 		WARN_ON(ret);
898 
899 		mutex_unlock(&test_dev->config_mutex);
900 		return -EINVAL;
901 	}
902 
903 	mutex_unlock(&test_dev->config_mutex);
904 	/* Always return full write size even if we didn't consume all */
905 	return size;
906 }
907 
test_dev_config_update_uint_range(struct kmod_test_device * test_dev,const char * buf,size_t size,unsigned int * config,unsigned int min,unsigned int max)908 static int test_dev_config_update_uint_range(struct kmod_test_device *test_dev,
909 					     const char *buf, size_t size,
910 					     unsigned int *config,
911 					     unsigned int min,
912 					     unsigned int max)
913 {
914 	unsigned int val;
915 	int ret;
916 
917 	ret = kstrtouint(buf, 10, &val);
918 	if (ret)
919 		return ret;
920 
921 	if (val < min || val > max)
922 		return -EINVAL;
923 
924 	mutex_lock(&test_dev->config_mutex);
925 	*config = val;
926 	mutex_unlock(&test_dev->config_mutex);
927 
928 	/* Always return full write size even if we didn't consume all */
929 	return size;
930 }
931 
test_dev_config_update_int(struct kmod_test_device * test_dev,const char * buf,size_t size,int * config)932 static int test_dev_config_update_int(struct kmod_test_device *test_dev,
933 				      const char *buf, size_t size,
934 				      int *config)
935 {
936 	int val;
937 	int ret;
938 
939 	ret = kstrtoint(buf, 10, &val);
940 	if (ret)
941 		return ret;
942 
943 	mutex_lock(&test_dev->config_mutex);
944 	*config = val;
945 	mutex_unlock(&test_dev->config_mutex);
946 	/* Always return full write size even if we didn't consume all */
947 	return size;
948 }
949 
test_dev_config_show_int(struct kmod_test_device * test_dev,char * buf,int config)950 static ssize_t test_dev_config_show_int(struct kmod_test_device *test_dev,
951 					char *buf,
952 					int config)
953 {
954 	int val;
955 
956 	mutex_lock(&test_dev->config_mutex);
957 	val = config;
958 	mutex_unlock(&test_dev->config_mutex);
959 
960 	return snprintf(buf, PAGE_SIZE, "%d\n", val);
961 }
962 
test_dev_config_show_uint(struct kmod_test_device * test_dev,char * buf,unsigned int config)963 static ssize_t test_dev_config_show_uint(struct kmod_test_device *test_dev,
964 					 char *buf,
965 					 unsigned int config)
966 {
967 	unsigned int val;
968 
969 	mutex_lock(&test_dev->config_mutex);
970 	val = config;
971 	mutex_unlock(&test_dev->config_mutex);
972 
973 	return snprintf(buf, PAGE_SIZE, "%u\n", val);
974 }
975 
test_result_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)976 static ssize_t test_result_store(struct device *dev,
977 				 struct device_attribute *attr,
978 				 const char *buf, size_t count)
979 {
980 	struct kmod_test_device *test_dev = dev_to_test_dev(dev);
981 	struct test_config *config = &test_dev->config;
982 
983 	return test_dev_config_update_int(test_dev, buf, count,
984 					  &config->test_result);
985 }
986 
config_num_threads_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)987 static ssize_t config_num_threads_store(struct device *dev,
988 					struct device_attribute *attr,
989 					const char *buf, size_t count)
990 {
991 	struct kmod_test_device *test_dev = dev_to_test_dev(dev);
992 	struct test_config *config = &test_dev->config;
993 
994 	return test_dev_config_update_uint_sync(test_dev, buf, count,
995 						&config->num_threads,
996 						kmod_config_sync_info);
997 }
998 
config_num_threads_show(struct device * dev,struct device_attribute * attr,char * buf)999 static ssize_t config_num_threads_show(struct device *dev,
1000 				       struct device_attribute *attr,
1001 				       char *buf)
1002 {
1003 	struct kmod_test_device *test_dev = dev_to_test_dev(dev);
1004 	struct test_config *config = &test_dev->config;
1005 
1006 	return test_dev_config_show_int(test_dev, buf, config->num_threads);
1007 }
1008 static DEVICE_ATTR_RW(config_num_threads);
1009 
config_test_case_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)1010 static ssize_t config_test_case_store(struct device *dev,
1011 				      struct device_attribute *attr,
1012 				      const char *buf, size_t count)
1013 {
1014 	struct kmod_test_device *test_dev = dev_to_test_dev(dev);
1015 	struct test_config *config = &test_dev->config;
1016 
1017 	return test_dev_config_update_uint_range(test_dev, buf, count,
1018 						 &config->test_case,
1019 						 __TEST_KMOD_INVALID + 1,
1020 						 __TEST_KMOD_MAX - 1);
1021 }
1022 
config_test_case_show(struct device * dev,struct device_attribute * attr,char * buf)1023 static ssize_t config_test_case_show(struct device *dev,
1024 				     struct device_attribute *attr,
1025 				     char *buf)
1026 {
1027 	struct kmod_test_device *test_dev = dev_to_test_dev(dev);
1028 	struct test_config *config = &test_dev->config;
1029 
1030 	return test_dev_config_show_uint(test_dev, buf, config->test_case);
1031 }
1032 static DEVICE_ATTR_RW(config_test_case);
1033 
test_result_show(struct device * dev,struct device_attribute * attr,char * buf)1034 static ssize_t test_result_show(struct device *dev,
1035 				struct device_attribute *attr,
1036 				char *buf)
1037 {
1038 	struct kmod_test_device *test_dev = dev_to_test_dev(dev);
1039 	struct test_config *config = &test_dev->config;
1040 
1041 	return test_dev_config_show_int(test_dev, buf, config->test_result);
1042 }
1043 static DEVICE_ATTR_RW(test_result);
1044 
1045 #define TEST_KMOD_DEV_ATTR(name)		&dev_attr_##name.attr
1046 
1047 static struct attribute *test_dev_attrs[] = {
1048 	TEST_KMOD_DEV_ATTR(trigger_config),
1049 	TEST_KMOD_DEV_ATTR(config),
1050 	TEST_KMOD_DEV_ATTR(reset),
1051 
1052 	TEST_KMOD_DEV_ATTR(config_test_driver),
1053 	TEST_KMOD_DEV_ATTR(config_test_fs),
1054 	TEST_KMOD_DEV_ATTR(config_num_threads),
1055 	TEST_KMOD_DEV_ATTR(config_test_case),
1056 	TEST_KMOD_DEV_ATTR(test_result),
1057 
1058 	NULL,
1059 };
1060 
1061 ATTRIBUTE_GROUPS(test_dev);
1062 
kmod_config_init(struct kmod_test_device * test_dev)1063 static int kmod_config_init(struct kmod_test_device *test_dev)
1064 {
1065 	int ret;
1066 
1067 	mutex_lock(&test_dev->config_mutex);
1068 	ret = __kmod_config_init(test_dev);
1069 	mutex_unlock(&test_dev->config_mutex);
1070 
1071 	return ret;
1072 }
1073 
alloc_test_dev_kmod(int idx)1074 static struct kmod_test_device *alloc_test_dev_kmod(int idx)
1075 {
1076 	int ret;
1077 	struct kmod_test_device *test_dev;
1078 	struct miscdevice *misc_dev;
1079 
1080 	test_dev = vzalloc(sizeof(struct kmod_test_device));
1081 	if (!test_dev)
1082 		goto err_out;
1083 
1084 	mutex_init(&test_dev->config_mutex);
1085 	mutex_init(&test_dev->trigger_mutex);
1086 	mutex_init(&test_dev->thread_mutex);
1087 
1088 	init_completion(&test_dev->kthreads_done);
1089 
1090 	ret = kmod_config_init(test_dev);
1091 	if (ret < 0) {
1092 		pr_err("Cannot alloc kmod_config_init()\n");
1093 		goto err_out_free;
1094 	}
1095 
1096 	test_dev->dev_idx = idx;
1097 	misc_dev = &test_dev->misc_dev;
1098 
1099 	misc_dev->minor = MISC_DYNAMIC_MINOR;
1100 	misc_dev->name = kasprintf(GFP_KERNEL, "test_kmod%d", idx);
1101 	if (!misc_dev->name) {
1102 		pr_err("Cannot alloc misc_dev->name\n");
1103 		goto err_out_free_config;
1104 	}
1105 	misc_dev->groups = test_dev_groups;
1106 
1107 	return test_dev;
1108 
1109 err_out_free_config:
1110 	free_test_dev_info(test_dev);
1111 	kmod_config_free(test_dev);
1112 err_out_free:
1113 	vfree(test_dev);
1114 	test_dev = NULL;
1115 err_out:
1116 	return NULL;
1117 }
1118 
free_test_dev_kmod(struct kmod_test_device * test_dev)1119 static void free_test_dev_kmod(struct kmod_test_device *test_dev)
1120 {
1121 	if (test_dev) {
1122 		kfree_const(test_dev->misc_dev.name);
1123 		test_dev->misc_dev.name = NULL;
1124 		free_test_dev_info(test_dev);
1125 		kmod_config_free(test_dev);
1126 		vfree(test_dev);
1127 		test_dev = NULL;
1128 	}
1129 }
1130 
register_test_dev_kmod(void)1131 static struct kmod_test_device *register_test_dev_kmod(void)
1132 {
1133 	struct kmod_test_device *test_dev = NULL;
1134 	int ret;
1135 
1136 	mutex_lock(&reg_dev_mutex);
1137 
1138 	/* int should suffice for number of devices, test for wrap */
1139 	if (num_test_devs + 1 == INT_MAX) {
1140 		pr_err("reached limit of number of test devices\n");
1141 		goto out;
1142 	}
1143 
1144 	test_dev = alloc_test_dev_kmod(num_test_devs);
1145 	if (!test_dev)
1146 		goto out;
1147 
1148 	ret = misc_register(&test_dev->misc_dev);
1149 	if (ret) {
1150 		pr_err("could not register misc device: %d\n", ret);
1151 		free_test_dev_kmod(test_dev);
1152 		test_dev = NULL;
1153 		goto out;
1154 	}
1155 
1156 	test_dev->dev = test_dev->misc_dev.this_device;
1157 	list_add_tail(&test_dev->list, &reg_test_devs);
1158 	dev_info(test_dev->dev, "interface ready\n");
1159 
1160 	num_test_devs++;
1161 
1162 out:
1163 	mutex_unlock(&reg_dev_mutex);
1164 
1165 	return test_dev;
1166 
1167 }
1168 
test_kmod_init(void)1169 static int __init test_kmod_init(void)
1170 {
1171 	struct kmod_test_device *test_dev;
1172 	int ret;
1173 
1174 	test_dev = register_test_dev_kmod();
1175 	if (!test_dev) {
1176 		pr_err("Cannot add first test kmod device\n");
1177 		return -ENODEV;
1178 	}
1179 
1180 	/*
1181 	 * With some work we might be able to gracefully enable
1182 	 * testing with this driver built-in, for now this seems
1183 	 * rather risky. For those willing to try have at it,
1184 	 * and enable the below. Good luck! If that works, try
1185 	 * lowering the init level for more fun.
1186 	 */
1187 	if (force_init_test) {
1188 		ret = trigger_config_run_type(test_dev,
1189 					      TEST_KMOD_DRIVER, "tun");
1190 		if (WARN_ON(ret))
1191 			return ret;
1192 		ret = trigger_config_run_type(test_dev,
1193 					      TEST_KMOD_FS_TYPE, "btrfs");
1194 		if (WARN_ON(ret))
1195 			return ret;
1196 	}
1197 
1198 	return 0;
1199 }
1200 late_initcall(test_kmod_init);
1201 
1202 static
unregister_test_dev_kmod(struct kmod_test_device * test_dev)1203 void unregister_test_dev_kmod(struct kmod_test_device *test_dev)
1204 {
1205 	mutex_lock(&test_dev->trigger_mutex);
1206 	mutex_lock(&test_dev->config_mutex);
1207 
1208 	test_dev_kmod_stop_tests(test_dev);
1209 
1210 	dev_info(test_dev->dev, "removing interface\n");
1211 	misc_deregister(&test_dev->misc_dev);
1212 
1213 	mutex_unlock(&test_dev->config_mutex);
1214 	mutex_unlock(&test_dev->trigger_mutex);
1215 
1216 	free_test_dev_kmod(test_dev);
1217 }
1218 
test_kmod_exit(void)1219 static void __exit test_kmod_exit(void)
1220 {
1221 	struct kmod_test_device *test_dev, *tmp;
1222 
1223 	mutex_lock(&reg_dev_mutex);
1224 	list_for_each_entry_safe(test_dev, tmp, &reg_test_devs, list) {
1225 		list_del(&test_dev->list);
1226 		unregister_test_dev_kmod(test_dev);
1227 	}
1228 	mutex_unlock(&reg_dev_mutex);
1229 }
1230 module_exit(test_kmod_exit);
1231 
1232 MODULE_AUTHOR("Luis R. Rodriguez <mcgrof@kernel.org>");
1233 MODULE_LICENSE("GPL");
1234