lib/test_kmod.c

   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(&reg_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, &reg_test_devs);
1151         dev_info(test_dev->dev, "interface ready\n");
1152
1153         num_test_devs++;
1154
1155 out:
1156         mutex_unlock(&reg_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(&reg_dev_mutex);
1217         list_for_each_entry_safe(test_dev, tmp, &reg_test_devs, list) {
1218                 list_del(&test_dev->list);
1219                 unregister_test_dev_kmod(test_dev);
1220         }
1221         mutex_unlock(&reg_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");