lib/test_kmod.c

   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
 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
 159 static struct miscdevice *dev_to_misc_dev(struct device *dev)
 160 {
 161         return dev_get_drvdata(dev);
 162 }
 163
 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
 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 */
 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
 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 && 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
 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
 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 sucess case.
 290  */
 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
 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
 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  */
 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
 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
 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
 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  */
 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
 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 possitive 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
 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 possitive 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  */
 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
 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
 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
 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_driver = NULL;
 636 }
 637
 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
 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  */
 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
 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
 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
 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
 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_driver = 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
 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
 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 = vzalloc(config->num_threads *
 783                                  sizeof(struct kmod_test_device_info));
 784         if (!test_dev->info)
 785                 return -ENOMEM;
 786
 787         return 0;
 788 }
 789
 790 /*
 791  * Old kernels may not have this, if you want to port this code to
 792  * test it on older kernels.
 793  */
 794 #ifdef get_kmod_umh_limit
 795 static unsigned int kmod_init_test_thread_limit(void)
 796 {
 797         return get_kmod_umh_limit();
 798 }
 799 #else
 800 static unsigned int kmod_init_test_thread_limit(void)
 801 {
 802         return TEST_START_NUM_THREADS;
 803 }
 804 #endif
 805
 806 static int __kmod_config_init(struct kmod_test_device *test_dev)
 807 {
 808         struct test_config *config = &test_dev->config;
 809         int ret = -ENOMEM, copied;
 810
 811         __kmod_config_free(config);
 812
 813         copied = config_copy_test_driver_name(config, TEST_START_DRIVER,
 814                                               strlen(TEST_START_DRIVER));
 815         if (copied != strlen(TEST_START_DRIVER))
 816                 goto err_out;
 817
 818         copied = config_copy_test_fs(config, TEST_START_TEST_FS,
 819                                      strlen(TEST_START_TEST_FS));
 820         if (copied != strlen(TEST_START_TEST_FS))
 821                 goto err_out;
 822
 823         config->num_threads = kmod_init_test_thread_limit();
 824         config->test_result = 0;
 825         config->test_case = TEST_START_TEST_CASE;
 826
 827         ret = kmod_config_sync_info(test_dev);
 828         if (ret)
 829                 goto err_out;
 830
 831         test_dev->test_is_oom = false;
 832
 833         return 0;
 834
 835 err_out:
 836         test_dev->test_is_oom = true;
 837         WARN_ON(test_dev->test_is_oom);
 838
 839         __kmod_config_free(config);
 840
 841         return ret;
 842 }
 843
 844 static ssize_t reset_store(struct device *dev,
 845                            struct device_attribute *attr,
 846                            const char *buf, size_t count)
 847 {
 848         struct kmod_test_device *test_dev = dev_to_test_dev(dev);
 849         int ret;
 850
 851         mutex_lock(&test_dev->trigger_mutex);
 852         mutex_lock(&test_dev->config_mutex);
 853
 854         ret = __kmod_config_init(test_dev);
 855         if (ret < 0) {
 856                 ret = -ENOMEM;
 857                 dev_err(dev, "could not alloc settings for config trigger: %d\n",
 858                        ret);
 859                 goto out;
 860         }
 861
 862         dev_info(dev, "reset\n");
 863         ret = count;
 864
 865 out:
 866         mutex_unlock(&test_dev->config_mutex);
 867         mutex_unlock(&test_dev->trigger_mutex);
 868
 869         return ret;
 870 }
 871 static DEVICE_ATTR_WO(reset);
 872
 873 static int test_dev_config_update_uint_sync(struct kmod_test_device *test_dev,
 874                                             const char *buf, size_t size,
 875                                             unsigned int *config,
 876                                             int (*test_sync)(struct kmod_test_device *test_dev))
 877 {
 878         int ret;
 879         unsigned long new;
 880         unsigned int old_val;
 881
 882         ret = kstrtoul(buf, 10, &new);
 883         if (ret)
 884                 return ret;
 885
 886         if (new > UINT_MAX)
 887                 return -EINVAL;
 888
 889         mutex_lock(&test_dev->config_mutex);
 890
 891         old_val = *config;
 892         *(unsigned int *)config = new;
 893
 894         ret = test_sync(test_dev);
 895         if (ret) {
 896                 *(unsigned int *)config = old_val;
 897
 898                 ret = test_sync(test_dev);
 899                 WARN_ON(ret);
 900
 901                 mutex_unlock(&test_dev->config_mutex);
 902                 return -EINVAL;
 903         }
 904
 905         mutex_unlock(&test_dev->config_mutex);
 906         /* Always return full write size even if we didn't consume all */
 907         return size;
 908 }
 909
 910 static int test_dev_config_update_uint_range(struct kmod_test_device *test_dev,
 911                                              const char *buf, size_t size,
 912                                              unsigned int *config,
 913                                              unsigned int min,
 914                                              unsigned int max)
 915 {
 916         int ret;
 917         unsigned long new;
 918
 919         ret = kstrtoul(buf, 10, &new);
 920         if (ret)
 921                 return ret;
 922
 923         if (new < min || new > max)
 924                 return -EINVAL;
 925
 926         mutex_lock(&test_dev->config_mutex);
 927         *config = new;
 928         mutex_unlock(&test_dev->config_mutex);
 929
 930         /* Always return full write size even if we didn't consume all */
 931         return size;
 932 }
 933
 934 static int test_dev_config_update_int(struct kmod_test_device *test_dev,
 935                                       const char *buf, size_t size,
 936                                       int *config)
 937 {
 938         int ret;
 939         long new;
 940
 941         ret = kstrtol(buf, 10, &new);
 942         if (ret)
 943                 return ret;
 944
 945         if (new < INT_MIN || new > INT_MAX)
 946                 return -EINVAL;
 947
 948         mutex_lock(&test_dev->config_mutex);
 949         *config = new;
 950         mutex_unlock(&test_dev->config_mutex);
 951         /* Always return full write size even if we didn't consume all */
 952         return size;
 953 }
 954
 955 static ssize_t test_dev_config_show_int(struct kmod_test_device *test_dev,
 956                                         char *buf,
 957                                         int config)
 958 {
 959         int val;
 960
 961         mutex_lock(&test_dev->config_mutex);
 962         val = config;
 963         mutex_unlock(&test_dev->config_mutex);
 964
 965         return snprintf(buf, PAGE_SIZE, "%d\n", val);
 966 }
 967
 968 static ssize_t test_dev_config_show_uint(struct kmod_test_device *test_dev,
 969                                          char *buf,
 970                                          unsigned int config)
 971 {
 972         unsigned int val;
 973
 974         mutex_lock(&test_dev->config_mutex);
 975         val = config;
 976         mutex_unlock(&test_dev->config_mutex);
 977
 978         return snprintf(buf, PAGE_SIZE, "%u\n", val);
 979 }
 980
 981 static ssize_t test_result_store(struct device *dev,
 982                                  struct device_attribute *attr,
 983                                  const char *buf, size_t count)
 984 {
 985         struct kmod_test_device *test_dev = dev_to_test_dev(dev);
 986         struct test_config *config = &test_dev->config;
 987
 988         return test_dev_config_update_int(test_dev, buf, count,
 989                                           &config->test_result);
 990 }
 991
 992 static ssize_t config_num_threads_store(struct device *dev,
 993                                         struct device_attribute *attr,
 994                                         const char *buf, size_t count)
 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_update_uint_sync(test_dev, buf, count,
1000                                                 &config->num_threads,
1001                                                 kmod_config_sync_info);
1002 }
1003
1004 static ssize_t config_num_threads_show(struct device *dev,
1005                                        struct device_attribute *attr,
1006                                        char *buf)
1007 {
1008         struct kmod_test_device *test_dev = dev_to_test_dev(dev);
1009         struct test_config *config = &test_dev->config;
1010
1011         return test_dev_config_show_int(test_dev, buf, config->num_threads);
1012 }
1013 static DEVICE_ATTR_RW(config_num_threads);
1014
1015 static ssize_t config_test_case_store(struct device *dev,
1016                                       struct device_attribute *attr,
1017                                       const char *buf, size_t count)
1018 {
1019         struct kmod_test_device *test_dev = dev_to_test_dev(dev);
1020         struct test_config *config = &test_dev->config;
1021
1022         return test_dev_config_update_uint_range(test_dev, buf, count,
1023                                                  &config->test_case,
1024                                                  __TEST_KMOD_INVALID + 1,
1025                                                  __TEST_KMOD_MAX - 1);
1026 }
1027
1028 static ssize_t config_test_case_show(struct device *dev,
1029                                      struct device_attribute *attr,
1030                                      char *buf)
1031 {
1032         struct kmod_test_device *test_dev = dev_to_test_dev(dev);
1033         struct test_config *config = &test_dev->config;
1034
1035         return test_dev_config_show_uint(test_dev, buf, config->test_case);
1036 }
1037 static DEVICE_ATTR_RW(config_test_case);
1038
1039 static ssize_t test_result_show(struct device *dev,
1040                                 struct device_attribute *attr,
1041                                 char *buf)
1042 {
1043         struct kmod_test_device *test_dev = dev_to_test_dev(dev);
1044         struct test_config *config = &test_dev->config;
1045
1046         return test_dev_config_show_int(test_dev, buf, config->test_result);
1047 }
1048 static DEVICE_ATTR_RW(test_result);
1049
1050 #define TEST_KMOD_DEV_ATTR(name)                &dev_attr_##name.attr
1051
1052 static struct attribute *test_dev_attrs[] = {
1053         TEST_KMOD_DEV_ATTR(trigger_config),
1054         TEST_KMOD_DEV_ATTR(config),
1055         TEST_KMOD_DEV_ATTR(reset),
1056
1057         TEST_KMOD_DEV_ATTR(config_test_driver),
1058         TEST_KMOD_DEV_ATTR(config_test_fs),
1059         TEST_KMOD_DEV_ATTR(config_num_threads),
1060         TEST_KMOD_DEV_ATTR(config_test_case),
1061         TEST_KMOD_DEV_ATTR(test_result),
1062
1063         NULL,
1064 };
1065
1066 ATTRIBUTE_GROUPS(test_dev);
1067
1068 static int kmod_config_init(struct kmod_test_device *test_dev)
1069 {
1070         int ret;
1071
1072         mutex_lock(&test_dev->config_mutex);
1073         ret = __kmod_config_init(test_dev);
1074         mutex_unlock(&test_dev->config_mutex);
1075
1076         return ret;
1077 }
1078
1079 static struct kmod_test_device *alloc_test_dev_kmod(int idx)
1080 {
1081         int ret;
1082         struct kmod_test_device *test_dev;
1083         struct miscdevice *misc_dev;
1084
1085         test_dev = vzalloc(sizeof(struct kmod_test_device));
1086         if (!test_dev)
1087                 goto err_out;
1088
1089         mutex_init(&test_dev->config_mutex);
1090         mutex_init(&test_dev->trigger_mutex);
1091         mutex_init(&test_dev->thread_mutex);
1092
1093         init_completion(&test_dev->kthreads_done);
1094
1095         ret = kmod_config_init(test_dev);
1096         if (ret < 0) {
1097                 pr_err("Cannot alloc kmod_config_init()\n");
1098                 goto err_out_free;
1099         }
1100
1101         test_dev->dev_idx = idx;
1102         misc_dev = &test_dev->misc_dev;
1103
1104         misc_dev->minor = MISC_DYNAMIC_MINOR;
1105         misc_dev->name = kasprintf(GFP_KERNEL, "test_kmod%d", idx);
1106         if (!misc_dev->name) {
1107                 pr_err("Cannot alloc misc_dev->name\n");
1108                 goto err_out_free_config;
1109         }
1110         misc_dev->groups = test_dev_groups;
1111
1112         return test_dev;
1113
1114 err_out_free_config:
1115         free_test_dev_info(test_dev);
1116         kmod_config_free(test_dev);
1117 err_out_free:
1118         vfree(test_dev);
1119         test_dev = NULL;
1120 err_out:
1121         return NULL;
1122 }
1123
1124 static void free_test_dev_kmod(struct kmod_test_device *test_dev)
1125 {
1126         if (test_dev) {
1127                 kfree_const(test_dev->misc_dev.name);
1128                 test_dev->misc_dev.name = NULL;
1129                 free_test_dev_info(test_dev);
1130                 kmod_config_free(test_dev);
1131                 vfree(test_dev);
1132                 test_dev = NULL;
1133         }
1134 }
1135
1136 static struct kmod_test_device *register_test_dev_kmod(void)
1137 {
1138         struct kmod_test_device *test_dev = NULL;
1139         int ret;
1140
1141         mutex_lock(&reg_dev_mutex);
1142
1143         /* int should suffice for number of devices, test for wrap */
1144         if (unlikely(num_test_devs + 1) < 0) {
1145                 pr_err("reached limit of number of test devices\n");
1146                 goto out;
1147         }
1148
1149         test_dev = alloc_test_dev_kmod(num_test_devs);
1150         if (!test_dev)
1151                 goto out;
1152
1153         ret = misc_register(&test_dev->misc_dev);
1154         if (ret) {
1155                 pr_err("could not register misc device: %d\n", ret);
1156                 free_test_dev_kmod(test_dev);
1157                 goto out;
1158         }
1159
1160         test_dev->dev = test_dev->misc_dev.this_device;
1161         list_add_tail(&test_dev->list, &reg_test_devs);
1162         dev_info(test_dev->dev, "interface ready\n");
1163
1164         num_test_devs++;
1165
1166 out:
1167         mutex_unlock(&reg_dev_mutex);
1168
1169         return test_dev;
1170
1171 }
1172
1173 static int __init test_kmod_init(void)
1174 {
1175         struct kmod_test_device *test_dev;
1176         int ret;
1177
1178         test_dev = register_test_dev_kmod();
1179         if (!test_dev) {
1180                 pr_err("Cannot add first test kmod device\n");
1181                 return -ENODEV;
1182         }
1183
1184         /*
1185          * With some work we might be able to gracefully enable
1186          * testing with this driver built-in, for now this seems
1187          * rather risky. For those willing to try have at it,
1188          * and enable the below. Good luck! If that works, try
1189          * lowering the init level for more fun.
1190          */
1191         if (force_init_test) {
1192                 ret = trigger_config_run_type(test_dev,
1193                                               TEST_KMOD_DRIVER, "tun");
1194                 if (WARN_ON(ret))
1195                         return ret;
1196                 ret = trigger_config_run_type(test_dev,
1197                                               TEST_KMOD_FS_TYPE, "btrfs");
1198                 if (WARN_ON(ret))
1199                         return ret;
1200         }
1201
1202         return 0;
1203 }
1204 late_initcall(test_kmod_init);
1205
1206 static
1207 void unregister_test_dev_kmod(struct kmod_test_device *test_dev)
1208 {
1209         mutex_lock(&test_dev->trigger_mutex);
1210         mutex_lock(&test_dev->config_mutex);
1211
1212         test_dev_kmod_stop_tests(test_dev);
1213
1214         dev_info(test_dev->dev, "removing interface\n");
1215         misc_deregister(&test_dev->misc_dev);
1216         kfree(&test_dev->misc_dev.name);
1217
1218         mutex_unlock(&test_dev->config_mutex);
1219         mutex_unlock(&test_dev->trigger_mutex);
1220
1221         free_test_dev_kmod(test_dev);
1222 }
1223
1224 static void __exit test_kmod_exit(void)
1225 {
1226         struct kmod_test_device *test_dev, *tmp;
1227
1228         mutex_lock(&reg_dev_mutex);
1229         list_for_each_entry_safe(test_dev, tmp, &reg_test_devs, list) {
1230                 list_del(&test_dev->list);
1231                 unregister_test_dev_kmod(test_dev);
1232         }
1233         mutex_unlock(&reg_dev_mutex);
1234 }
1235 module_exit(test_kmod_exit);
1236
1237 MODULE_AUTHOR("Luis R. Rodriguez <mcgrof@kernel.org>");
1238 MODULE_LICENSE("GPL");