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
  45static bool force_init_test = false;
  46module_param(force_init_test, bool_enable_only, 0644);
  47MODULE_PARM_DESC(force_init_test,
  48		 "Force kicking a test immediately after driver loads");
  49
  50/*
  51 * For device allocation / registration
  52 */
  53static DEFINE_MUTEX(reg_dev_mutex);
  54static 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 */
  60static 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 */
  71enum 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
  80struct 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
  88struct 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 */
 104struct 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 */
 129struct 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
 147static 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
 159static struct miscdevice *dev_to_misc_dev(struct device *dev)
 160{
 161	return dev_get_drvdata(dev);
 162}
 163
 164static 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
 169static 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 */
 179static 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
 195static 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
 217static 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
 249static 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 */
 291static 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
 319static 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
 343err_out:
 344	info->ret_sync = fail_ret;
 345	mutex_unlock(&test_dev->thread_mutex);
 346
 347	return fail_ret;
 348}
 349
 350static 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 */
 388static 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
 425static 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
 442static 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
 459static 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}
 502static DEVICE_ATTR_RO(config);
 503
 504/*
 505 * This ensures we don't allow kicking threads through if our configuration
 506 * is faulty.
 507 */
 508static 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
 527static 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
 556out:
 557	mutex_unlock(&test_dev->config_mutex);
 558	mutex_unlock(&test_dev->trigger_mutex);
 559
 560	return ret;
 561}
 562
 563static ssize_t
 564trigger_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;
 594out:
 595	return ret;
 596}
 597static 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 */
 604static 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
 612static 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
 620static 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
 626static 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
 638static 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
 652static 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 */
 674static 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
 687static 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}
 697static DEVICE_ATTR_RW(config_test_driver);
 698
 699static 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
 718static 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}
 728static DEVICE_ATTR_RW(config_test_fs);
 729
 730static 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
 771static void free_test_dev_info(struct kmod_test_device *test_dev)
 772{
 773	vfree(test_dev->info);
 774	test_dev->info = NULL;
 775}
 776
 777static 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
 796static unsigned int kmod_init_test_thread_limit(void)
 797{
 798	return get_kmod_umh_limit();
 799}
 800#else
 801static unsigned int kmod_init_test_thread_limit(void)
 802{
 803	return TEST_START_NUM_THREADS;
 804}
 805#endif
 806
 807static 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
 836err_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
 845static 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
 866out:
 867	mutex_unlock(&test_dev->config_mutex);
 868	mutex_unlock(&test_dev->trigger_mutex);
 869
 870	return ret;
 871}
 872static DEVICE_ATTR_WO(reset);
 873
 874static 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
 908static 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
 932static 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
 950static 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
 963static 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
 976static 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
 987static 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
 999static 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}
1008static DEVICE_ATTR_RW(config_num_threads);
1009
1010static 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
1023static 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}
1032static DEVICE_ATTR_RW(config_test_case);
1033
1034static 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}
1043static DEVICE_ATTR_RW(test_result);
1044
1045#define TEST_KMOD_DEV_ATTR(name)		&dev_attr_##name.attr
1046
1047static 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
1061ATTRIBUTE_GROUPS(test_dev);
1062
1063static 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
1074static 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
1109err_out_free_config:
1110	free_test_dev_info(test_dev);
1111	kmod_config_free(test_dev);
1112err_out_free:
1113	vfree(test_dev);
1114	test_dev = NULL;
1115err_out:
1116	return NULL;
1117}
1118
1119static 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
1131static 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		goto out;
1153	}
1154
1155	test_dev->dev = test_dev->misc_dev.this_device;
1156	list_add_tail(&test_dev->list, &reg_test_devs);
1157	dev_info(test_dev->dev, "interface ready\n");
1158
1159	num_test_devs++;
1160
1161out:
1162	mutex_unlock(&reg_dev_mutex);
1163
1164	return test_dev;
1165
1166}
1167
1168static int __init test_kmod_init(void)
1169{
1170	struct kmod_test_device *test_dev;
1171	int ret;
1172
1173	test_dev = register_test_dev_kmod();
1174	if (!test_dev) {
1175		pr_err("Cannot add first test kmod device\n");
1176		return -ENODEV;
1177	}
1178
1179	/*
1180	 * With some work we might be able to gracefully enable
1181	 * testing with this driver built-in, for now this seems
1182	 * rather risky. For those willing to try have at it,
1183	 * and enable the below. Good luck! If that works, try
1184	 * lowering the init level for more fun.
1185	 */
1186	if (force_init_test) {
1187		ret = trigger_config_run_type(test_dev,
1188					      TEST_KMOD_DRIVER, "tun");
1189		if (WARN_ON(ret))
1190			return ret;
1191		ret = trigger_config_run_type(test_dev,
1192					      TEST_KMOD_FS_TYPE, "btrfs");
1193		if (WARN_ON(ret))
1194			return ret;
1195	}
1196
1197	return 0;
1198}
1199late_initcall(test_kmod_init);
1200
1201static
1202void unregister_test_dev_kmod(struct kmod_test_device *test_dev)
1203{
1204	mutex_lock(&test_dev->trigger_mutex);
1205	mutex_lock(&test_dev->config_mutex);
1206
1207	test_dev_kmod_stop_tests(test_dev);
1208
1209	dev_info(test_dev->dev, "removing interface\n");
1210	misc_deregister(&test_dev->misc_dev);
 
1211
1212	mutex_unlock(&test_dev->config_mutex);
1213	mutex_unlock(&test_dev->trigger_mutex);
1214
1215	free_test_dev_kmod(test_dev);
1216}
1217
1218static void __exit test_kmod_exit(void)
1219{
1220	struct kmod_test_device *test_dev, *tmp;
1221
1222	mutex_lock(&reg_dev_mutex);
1223	list_for_each_entry_safe(test_dev, tmp, &reg_test_devs, list) {
1224		list_del(&test_dev->list);
1225		unregister_test_dev_kmod(test_dev);
1226	}
1227	mutex_unlock(&reg_dev_mutex);
1228}
1229module_exit(test_kmod_exit);
1230
1231MODULE_AUTHOR("Luis R. Rodriguez <mcgrof@kernel.org>");
1232MODULE_LICENSE("GPL");