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 =
 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
 796 static unsigned int kmod_init_test_thread_limit(void)
 797 {
 798         return get_kmod_umh_limit();
 799 }
 800 #else
 801 static unsigned int kmod_init_test_thread_limit(void)
 802 {
 803         return TEST_START_NUM_THREADS;
 804 }
 805 #endif
 806
 807 static int __kmod_config_init(struct kmod_test_device *test_dev)
 808 {
 809         struct test_config *config = &test_dev->config;
 810         int ret = -ENOMEM, copied;
 811
 812         __kmod_config_free(config);
 813
 814         copied = config_copy_test_driver_name(config, TEST_START_DRIVER,
 815                                               strlen(TEST_START_DRIVER));
 816         if (copied != strlen(TEST_START_DRIVER))
 817                 goto err_out;
 818
 819         copied = config_copy_test_fs(config, TEST_START_TEST_FS,
 820                                      strlen(TEST_START_TEST_FS));
 821         if (copied != strlen(TEST_START_TEST_FS))
 822                 goto err_out;
 823
 824         config->num_threads = kmod_init_test_thread_limit();
 825         config->test_result = 0;
 826         config->test_case = TEST_START_TEST_CASE;
 827
 828         ret = kmod_config_sync_info(test_dev);
 829         if (ret)
 830                 goto err_out;
 831
 832         test_dev->test_is_oom = false;
 833
 834         return 0;
 835
 836 err_out:
 837         test_dev->test_is_oom = true;
 838         WARN_ON(test_dev->test_is_oom);
 839
 840         __kmod_config_free(config);
 841
 842         return ret;
 843 }
 844
 845 static ssize_t reset_store(struct device *dev,
 846                            struct device_attribute *attr,
 847                            const char *buf, size_t count)
 848 {
 849         struct kmod_test_device *test_dev = dev_to_test_dev(dev);
 850         int ret;
 851
 852         mutex_lock(&test_dev->trigger_mutex);
 853         mutex_lock(&test_dev->config_mutex);
 854
 855         ret = __kmod_config_init(test_dev);
 856         if (ret < 0) {
 857                 ret = -ENOMEM;
 858                 dev_err(dev, "could not alloc settings for config trigger: %d\n",
 859                        ret);
 860                 goto out;
 861         }
 862
 863         dev_info(dev, "reset\n");
 864         ret = count;
 865
 866 out:
 867         mutex_unlock(&test_dev->config_mutex);
 868         mutex_unlock(&test_dev->trigger_mutex);
 869
 870         return ret;
 871 }
 872 static DEVICE_ATTR_WO(reset);
 873
 874 static int test_dev_config_update_uint_sync(struct kmod_test_device *test_dev,
 875                                             const char *buf, size_t size,
 876                                             unsigned int *config,
 877                                             int (*test_sync)(struct kmod_test_device *test_dev))
 878 {
 879         int ret;
 880         unsigned long new;
 881         unsigned int old_val;
 882
 883         ret = kstrtoul(buf, 10, &new);
 884         if (ret)
 885                 return ret;
 886
 887         if (new > UINT_MAX)
 888                 return -EINVAL;
 889
 890         mutex_lock(&test_dev->config_mutex);
 891
 892         old_val = *config;
 893         *(unsigned int *)config = new;
 894
 895         ret = test_sync(test_dev);
 896         if (ret) {
 897                 *(unsigned int *)config = old_val;
 898
 899                 ret = test_sync(test_dev);
 900                 WARN_ON(ret);
 901
 902                 mutex_unlock(&test_dev->config_mutex);
 903                 return -EINVAL;
 904         }
 905
 906         mutex_unlock(&test_dev->config_mutex);
 907         /* Always return full write size even if we didn't consume all */
 908         return size;
 909 }
 910
 911 static int test_dev_config_update_uint_range(struct kmod_test_device *test_dev,
 912                                              const char *buf, size_t size,
 913                                              unsigned int *config,
 914                                              unsigned int min,
 915                                              unsigned int max)
 916 {
 917         int ret;
 918         unsigned long new;
 919
 920         ret = kstrtoul(buf, 10, &new);
 921         if (ret)
 922                 return ret;
 923
 924         if (new < min || new > max)
 925                 return -EINVAL;
 926
 927         mutex_lock(&test_dev->config_mutex);
 928         *config = new;
 929         mutex_unlock(&test_dev->config_mutex);
 930
 931         /* Always return full write size even if we didn't consume all */
 932         return size;
 933 }
 934
 935 static int test_dev_config_update_int(struct kmod_test_device *test_dev,
 936                                       const char *buf, size_t size,
 937                                       int *config)
 938 {
 939         int ret;
 940         long new;
 941
 942         ret = kstrtol(buf, 10, &new);
 943         if (ret)
 944                 return ret;
 945
 946         if (new < INT_MIN || new > INT_MAX)
 947                 return -EINVAL;
 948
 949         mutex_lock(&test_dev->config_mutex);
 950         *config = new;
 951         mutex_unlock(&test_dev->config_mutex);
 952         /* Always return full write size even if we didn't consume all */
 953         return size;
 954 }
 955
 956 static ssize_t test_dev_config_show_int(struct kmod_test_device *test_dev,
 957                                         char *buf,
 958                                         int config)
 959 {
 960         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, "%d\n", val);
 967 }
 968
 969 static ssize_t test_dev_config_show_uint(struct kmod_test_device *test_dev,
 970                                          char *buf,
 971                                          unsigned int config)
 972 {
 973         unsigned int val;
 974
 975         mutex_lock(&test_dev->config_mutex);
 976         val = config;
 977         mutex_unlock(&test_dev->config_mutex);
 978
 979         return snprintf(buf, PAGE_SIZE, "%u\n", val);
 980 }
 981
 982 static ssize_t test_result_store(struct device *dev,
 983                                  struct device_attribute *attr,
 984                                  const char *buf, size_t count)
 985 {
 986         struct kmod_test_device *test_dev = dev_to_test_dev(dev);
 987         struct test_config *config = &test_dev->config;
 988
 989         return test_dev_config_update_int(test_dev, buf, count,
 990                                           &config->test_result);
 991 }
 992
 993 static ssize_t config_num_threads_store(struct device *dev,
 994                                         struct device_attribute *attr,
 995                                         const char *buf, size_t count)
 996 {
 997         struct kmod_test_device *test_dev = dev_to_test_dev(dev);
 998         struct test_config *config = &test_dev->config;
 999
1000         return test_dev_config_update_uint_sync(test_dev, buf, count,
1001                                                 &config->num_threads,
1002                                                 kmod_config_sync_info);
1003 }
1004
1005 static ssize_t config_num_threads_show(struct device *dev,
1006                                        struct device_attribute *attr,
1007                                        char *buf)
1008 {
1009         struct kmod_test_device *test_dev = dev_to_test_dev(dev);
1010         struct test_config *config = &test_dev->config;
1011
1012         return test_dev_config_show_int(test_dev, buf, config->num_threads);
1013 }
1014 static DEVICE_ATTR_RW(config_num_threads);
1015
1016 static ssize_t config_test_case_store(struct device *dev,
1017                                       struct device_attribute *attr,
1018                                       const char *buf, size_t count)
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_update_uint_range(test_dev, buf, count,
1024                                                  &config->test_case,
1025                                                  __TEST_KMOD_INVALID + 1,
1026                                                  __TEST_KMOD_MAX - 1);
1027 }
1028
1029 static ssize_t config_test_case_show(struct device *dev,
1030                                      struct device_attribute *attr,
1031                                      char *buf)
1032 {
1033         struct kmod_test_device *test_dev = dev_to_test_dev(dev);
1034         struct test_config *config = &test_dev->config;
1035
1036         return test_dev_config_show_uint(test_dev, buf, config->test_case);
1037 }
1038 static DEVICE_ATTR_RW(config_test_case);
1039
1040 static ssize_t test_result_show(struct device *dev,
1041                                 struct device_attribute *attr,
1042                                 char *buf)
1043 {
1044         struct kmod_test_device *test_dev = dev_to_test_dev(dev);
1045         struct test_config *config = &test_dev->config;
1046
1047         return test_dev_config_show_int(test_dev, buf, config->test_result);
1048 }
1049 static DEVICE_ATTR_RW(test_result);
1050
1051 #define TEST_KMOD_DEV_ATTR(name)                &dev_attr_##name.attr
1052
1053 static struct attribute *test_dev_attrs[] = {
1054         TEST_KMOD_DEV_ATTR(trigger_config),
1055         TEST_KMOD_DEV_ATTR(config),
1056         TEST_KMOD_DEV_ATTR(reset),
1057
1058         TEST_KMOD_DEV_ATTR(config_test_driver),
1059         TEST_KMOD_DEV_ATTR(config_test_fs),
1060         TEST_KMOD_DEV_ATTR(config_num_threads),
1061         TEST_KMOD_DEV_ATTR(config_test_case),
1062         TEST_KMOD_DEV_ATTR(test_result),
1063
1064         NULL,
1065 };
1066
1067 ATTRIBUTE_GROUPS(test_dev);
1068
1069 static int kmod_config_init(struct kmod_test_device *test_dev)
1070 {
1071         int ret;
1072
1073         mutex_lock(&test_dev->config_mutex);
1074         ret = __kmod_config_init(test_dev);
1075         mutex_unlock(&test_dev->config_mutex);
1076
1077         return ret;
1078 }
1079
1080 static struct kmod_test_device *alloc_test_dev_kmod(int idx)
1081 {
1082         int ret;
1083         struct kmod_test_device *test_dev;
1084         struct miscdevice *misc_dev;
1085
1086         test_dev = vzalloc(sizeof(struct kmod_test_device));
1087         if (!test_dev)
1088                 goto err_out;
1089
1090         mutex_init(&test_dev->config_mutex);
1091         mutex_init(&test_dev->trigger_mutex);
1092         mutex_init(&test_dev->thread_mutex);
1093
1094         init_completion(&test_dev->kthreads_done);
1095
1096         ret = kmod_config_init(test_dev);
1097         if (ret < 0) {
1098                 pr_err("Cannot alloc kmod_config_init()\n");
1099                 goto err_out_free;
1100         }
1101
1102         test_dev->dev_idx = idx;
1103         misc_dev = &test_dev->misc_dev;
1104
1105         misc_dev->minor = MISC_DYNAMIC_MINOR;
1106         misc_dev->name = kasprintf(GFP_KERNEL, "test_kmod%d", idx);
1107         if (!misc_dev->name) {
1108                 pr_err("Cannot alloc misc_dev->name\n");
1109                 goto err_out_free_config;
1110         }
1111         misc_dev->groups = test_dev_groups;
1112
1113         return test_dev;
1114
1115 err_out_free_config:
1116         free_test_dev_info(test_dev);
1117         kmod_config_free(test_dev);
1118 err_out_free:
1119         vfree(test_dev);
1120         test_dev = NULL;
1121 err_out:
1122         return NULL;
1123 }
1124
1125 static void free_test_dev_kmod(struct kmod_test_device *test_dev)
1126 {
1127         if (test_dev) {
1128                 kfree_const(test_dev->misc_dev.name);
1129                 test_dev->misc_dev.name = NULL;
1130                 free_test_dev_info(test_dev);
1131                 kmod_config_free(test_dev);
1132                 vfree(test_dev);
1133                 test_dev = NULL;
1134         }
1135 }
1136
1137 static struct kmod_test_device *register_test_dev_kmod(void)
1138 {
1139         struct kmod_test_device *test_dev = NULL;
1140         int ret;
1141
1142         mutex_lock(&reg_dev_mutex);
1143
1144         /* int should suffice for number of devices, test for wrap */
1145         if (num_test_devs + 1 == INT_MAX) {
1146                 pr_err("reached limit of number of test devices\n");
1147                 goto out;
1148         }
1149
1150         test_dev = alloc_test_dev_kmod(num_test_devs);
1151         if (!test_dev)
1152                 goto out;
1153
1154         ret = misc_register(&test_dev->misc_dev);
1155         if (ret) {
1156                 pr_err("could not register misc device: %d\n", ret);
1157                 free_test_dev_kmod(test_dev);
1158                 goto out;
1159         }
1160
1161         test_dev->dev = test_dev->misc_dev.this_device;
1162         list_add_tail(&test_dev->list, &reg_test_devs);
1163         dev_info(test_dev->dev, "interface ready\n");
1164
1165         num_test_devs++;
1166
1167 out:
1168         mutex_unlock(&reg_dev_mutex);
1169
1170         return test_dev;
1171
1172 }
1173
1174 static int __init test_kmod_init(void)
1175 {
1176         struct kmod_test_device *test_dev;
1177         int ret;
1178
1179         test_dev = register_test_dev_kmod();
1180         if (!test_dev) {
1181                 pr_err("Cannot add first test kmod device\n");
1182                 return -ENODEV;
1183         }
1184
1185         /*
1186          * With some work we might be able to gracefully enable
1187          * testing with this driver built-in, for now this seems
1188          * rather risky. For those willing to try have at it,
1189          * and enable the below. Good luck! If that works, try
1190          * lowering the init level for more fun.
1191          */
1192         if (force_init_test) {
1193                 ret = trigger_config_run_type(test_dev,
1194                                               TEST_KMOD_DRIVER, "tun");
1195                 if (WARN_ON(ret))
1196                         return ret;
1197                 ret = trigger_config_run_type(test_dev,
1198                                               TEST_KMOD_FS_TYPE, "btrfs");
1199                 if (WARN_ON(ret))
1200                         return ret;
1201         }
1202
1203         return 0;
1204 }
1205 late_initcall(test_kmod_init);
1206
1207 static
1208 void unregister_test_dev_kmod(struct kmod_test_device *test_dev)
1209 {
1210         mutex_lock(&test_dev->trigger_mutex);
1211         mutex_lock(&test_dev->config_mutex);
1212
1213         test_dev_kmod_stop_tests(test_dev);
1214
1215         dev_info(test_dev->dev, "removing interface\n");
1216         misc_deregister(&test_dev->misc_dev);
1217         kfree(&test_dev->misc_dev.name);
1218
1219         mutex_unlock(&test_dev->config_mutex);
1220         mutex_unlock(&test_dev->trigger_mutex);
1221
1222         free_test_dev_kmod(test_dev);
1223 }
1224
1225 static void __exit test_kmod_exit(void)
1226 {
1227         struct kmod_test_device *test_dev, *tmp;
1228
1229         mutex_lock(&reg_dev_mutex);
1230         list_for_each_entry_safe(test_dev, tmp, &reg_test_devs, list) {
1231                 list_del(&test_dev->list);
1232                 unregister_test_dev_kmod(test_dev);
1233         }
1234         mutex_unlock(&reg_dev_mutex);
1235 }
1236 module_exit(test_kmod_exit);
1237
1238 MODULE_AUTHOR("Luis R. Rodriguez <mcgrof@kernel.org>");
1239 MODULE_LICENSE("GPL");