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(config_test_driver, 0644, config_test_driver_show,
 698                    config_test_driver_store);
 699
 700 static ssize_t config_test_fs_store(struct device *dev,
 701                                     struct device_attribute *attr,
 702                                     const char *buf, size_t count)
 703 {
 704         struct kmod_test_device *test_dev = dev_to_test_dev(dev);
 705         struct test_config *config = &test_dev->config;
 706         int copied;
 707
 708         mutex_lock(&test_dev->config_mutex);
 709
 710         kfree_const(config->test_fs);
 711         config->test_fs = NULL;
 712
 713         copied = config_copy_test_fs(config, buf, count);
 714         mutex_unlock(&test_dev->config_mutex);
 715
 716         return copied;
 717 }
 718
 719 static ssize_t config_test_fs_show(struct device *dev,
 720                                    struct device_attribute *attr,
 721                                    char *buf)
 722 {
 723         struct kmod_test_device *test_dev = dev_to_test_dev(dev);
 724         struct test_config *config = &test_dev->config;
 725
 726         return config_test_show_str(&test_dev->config_mutex, buf,
 727                                     config->test_fs);
 728 }
 729 static DEVICE_ATTR(config_test_fs, 0644, config_test_fs_show,
 730                    config_test_fs_store);
 731
 732 static int trigger_config_run_type(struct kmod_test_device *test_dev,
 733                                    enum kmod_test_case test_case,
 734                                    const char *test_str)
 735 {
 736         int copied = 0;
 737         struct test_config *config = &test_dev->config;
 738
 739         mutex_lock(&test_dev->config_mutex);
 740
 741         switch (test_case) {
 742         case TEST_KMOD_DRIVER:
 743                 kfree_const(config->test_driver);
 744                 config->test_driver = NULL;
 745                 copied = config_copy_test_driver_name(config, test_str,
 746                                                       strlen(test_str));
 747                 break;
 748         case TEST_KMOD_FS_TYPE:
 749                 kfree_const(config->test_fs);
 750                 config->test_driver = NULL;
 751                 copied = config_copy_test_fs(config, test_str,
 752                                              strlen(test_str));
 753                 break;
 754         default:
 755                 mutex_unlock(&test_dev->config_mutex);
 756                 return -EINVAL;
 757         }
 758
 759         config->test_case = test_case;
 760
 761         mutex_unlock(&test_dev->config_mutex);
 762
 763         if (copied <= 0 || copied != strlen(test_str)) {
 764                 test_dev->test_is_oom = true;
 765                 return -ENOMEM;
 766         }
 767
 768         test_dev->test_is_oom = false;
 769
 770         return trigger_config_run(test_dev);
 771 }
 772
 773 static void free_test_dev_info(struct kmod_test_device *test_dev)
 774 {
 775         vfree(test_dev->info);
 776         test_dev->info = NULL;
 777 }
 778
 779 static int kmod_config_sync_info(struct kmod_test_device *test_dev)
 780 {
 781         struct test_config *config = &test_dev->config;
 782
 783         free_test_dev_info(test_dev);
 784         test_dev->info = vzalloc(config->num_threads *
 785                                  sizeof(struct kmod_test_device_info));
 786         if (!test_dev->info) {
 787                 dev_err(test_dev->dev, "Cannot alloc test_dev info\n");
 788                 return -ENOMEM;
 789         }
 790
 791         return 0;
 792 }
 793
 794 /*
 795  * Old kernels may not have this, if you want to port this code to
 796  * test it on older kernels.
 797  */
 798 #ifdef get_kmod_umh_limit
 799 static unsigned int kmod_init_test_thread_limit(void)
 800 {
 801         return get_kmod_umh_limit();
 802 }
 803 #else
 804 static unsigned int kmod_init_test_thread_limit(void)
 805 {
 806         return TEST_START_NUM_THREADS;
 807 }
 808 #endif
 809
 810 static int __kmod_config_init(struct kmod_test_device *test_dev)
 811 {
 812         struct test_config *config = &test_dev->config;
 813         int ret = -ENOMEM, copied;
 814
 815         __kmod_config_free(config);
 816
 817         copied = config_copy_test_driver_name(config, TEST_START_DRIVER,
 818                                               strlen(TEST_START_DRIVER));
 819         if (copied != strlen(TEST_START_DRIVER))
 820                 goto err_out;
 821
 822         copied = config_copy_test_fs(config, TEST_START_TEST_FS,
 823                                      strlen(TEST_START_TEST_FS));
 824         if (copied != strlen(TEST_START_TEST_FS))
 825                 goto err_out;
 826
 827         config->num_threads = kmod_init_test_thread_limit();
 828         config->test_result = 0;
 829         config->test_case = TEST_START_TEST_CASE;
 830
 831         ret = kmod_config_sync_info(test_dev);
 832         if (ret)
 833                 goto err_out;
 834
 835         test_dev->test_is_oom = false;
 836
 837         return 0;
 838
 839 err_out:
 840         test_dev->test_is_oom = true;
 841         WARN_ON(test_dev->test_is_oom);
 842
 843         __kmod_config_free(config);
 844
 845         return ret;
 846 }
 847
 848 static ssize_t reset_store(struct device *dev,
 849                            struct device_attribute *attr,
 850                            const char *buf, size_t count)
 851 {
 852         struct kmod_test_device *test_dev = dev_to_test_dev(dev);
 853         int ret;
 854
 855         mutex_lock(&test_dev->trigger_mutex);
 856         mutex_lock(&test_dev->config_mutex);
 857
 858         ret = __kmod_config_init(test_dev);
 859         if (ret < 0) {
 860                 ret = -ENOMEM;
 861                 dev_err(dev, "could not alloc settings for config trigger: %d\n",
 862                        ret);
 863                 goto out;
 864         }
 865
 866         dev_info(dev, "reset\n");
 867         ret = count;
 868
 869 out:
 870         mutex_unlock(&test_dev->config_mutex);
 871         mutex_unlock(&test_dev->trigger_mutex);
 872
 873         return ret;
 874 }
 875 static DEVICE_ATTR_WO(reset);
 876
 877 static int test_dev_config_update_uint_sync(struct kmod_test_device *test_dev,
 878                                             const char *buf, size_t size,
 879                                             unsigned int *config,
 880                                             int (*test_sync)(struct kmod_test_device *test_dev))
 881 {
 882         int ret;
 883         unsigned long new;
 884         unsigned int old_val;
 885
 886         ret = kstrtoul(buf, 10, &new);
 887         if (ret)
 888                 return ret;
 889
 890         if (new > UINT_MAX)
 891                 return -EINVAL;
 892
 893         mutex_lock(&test_dev->config_mutex);
 894
 895         old_val = *config;
 896         *(unsigned int *)config = new;
 897
 898         ret = test_sync(test_dev);
 899         if (ret) {
 900                 *(unsigned int *)config = old_val;
 901
 902                 ret = test_sync(test_dev);
 903                 WARN_ON(ret);
 904
 905                 mutex_unlock(&test_dev->config_mutex);
 906                 return -EINVAL;
 907         }
 908
 909         mutex_unlock(&test_dev->config_mutex);
 910         /* Always return full write size even if we didn't consume all */
 911         return size;
 912 }
 913
 914 static int test_dev_config_update_uint_range(struct kmod_test_device *test_dev,
 915                                              const char *buf, size_t size,
 916                                              unsigned int *config,
 917                                              unsigned int min,
 918                                              unsigned int max)
 919 {
 920         int ret;
 921         unsigned long new;
 922
 923         ret = kstrtoul(buf, 10, &new);
 924         if (ret)
 925                 return ret;
 926
 927         if (new < min || new > max)
 928                 return -EINVAL;
 929
 930         mutex_lock(&test_dev->config_mutex);
 931         *config = new;
 932         mutex_unlock(&test_dev->config_mutex);
 933
 934         /* Always return full write size even if we didn't consume all */
 935         return size;
 936 }
 937
 938 static int test_dev_config_update_int(struct kmod_test_device *test_dev,
 939                                       const char *buf, size_t size,
 940                                       int *config)
 941 {
 942         int ret;
 943         long new;
 944
 945         ret = kstrtol(buf, 10, &new);
 946         if (ret)
 947                 return ret;
 948
 949         if (new < INT_MIN || new > INT_MAX)
 950                 return -EINVAL;
 951
 952         mutex_lock(&test_dev->config_mutex);
 953         *config = new;
 954         mutex_unlock(&test_dev->config_mutex);
 955         /* Always return full write size even if we didn't consume all */
 956         return size;
 957 }
 958
 959 static ssize_t test_dev_config_show_int(struct kmod_test_device *test_dev,
 960                                         char *buf,
 961                                         int config)
 962 {
 963         int val;
 964
 965         mutex_lock(&test_dev->config_mutex);
 966         val = config;
 967         mutex_unlock(&test_dev->config_mutex);
 968
 969         return snprintf(buf, PAGE_SIZE, "%d\n", val);
 970 }
 971
 972 static ssize_t test_dev_config_show_uint(struct kmod_test_device *test_dev,
 973                                          char *buf,
 974                                          unsigned int config)
 975 {
 976         unsigned int val;
 977
 978         mutex_lock(&test_dev->config_mutex);
 979         val = config;
 980         mutex_unlock(&test_dev->config_mutex);
 981
 982         return snprintf(buf, PAGE_SIZE, "%u\n", val);
 983 }
 984
 985 static ssize_t test_result_store(struct device *dev,
 986                                  struct device_attribute *attr,
 987                                  const char *buf, size_t count)
 988 {
 989         struct kmod_test_device *test_dev = dev_to_test_dev(dev);
 990         struct test_config *config = &test_dev->config;
 991
 992         return test_dev_config_update_int(test_dev, buf, count,
 993                                           &config->test_result);
 994 }
 995
 996 static ssize_t config_num_threads_store(struct device *dev,
 997                                         struct device_attribute *attr,
 998                                         const char *buf, size_t count)
 999 {
1000         struct kmod_test_device *test_dev = dev_to_test_dev(dev);
1001         struct test_config *config = &test_dev->config;
1002
1003         return test_dev_config_update_uint_sync(test_dev, buf, count,
1004                                                 &config->num_threads,
1005                                                 kmod_config_sync_info);
1006 }
1007
1008 static ssize_t config_num_threads_show(struct device *dev,
1009                                        struct device_attribute *attr,
1010                                        char *buf)
1011 {
1012         struct kmod_test_device *test_dev = dev_to_test_dev(dev);
1013         struct test_config *config = &test_dev->config;
1014
1015         return test_dev_config_show_int(test_dev, buf, config->num_threads);
1016 }
1017 static DEVICE_ATTR(config_num_threads, 0644, config_num_threads_show,
1018                    config_num_threads_store);
1019
1020 static ssize_t config_test_case_store(struct device *dev,
1021                                       struct device_attribute *attr,
1022                                       const char *buf, size_t count)
1023 {
1024         struct kmod_test_device *test_dev = dev_to_test_dev(dev);
1025         struct test_config *config = &test_dev->config;
1026
1027         return test_dev_config_update_uint_range(test_dev, buf, count,
1028                                                  &config->test_case,
1029                                                  __TEST_KMOD_INVALID + 1,
1030                                                  __TEST_KMOD_MAX - 1);
1031 }
1032
1033 static ssize_t config_test_case_show(struct device *dev,
1034                                      struct device_attribute *attr,
1035                                      char *buf)
1036 {
1037         struct kmod_test_device *test_dev = dev_to_test_dev(dev);
1038         struct test_config *config = &test_dev->config;
1039
1040         return test_dev_config_show_uint(test_dev, buf, config->test_case);
1041 }
1042 static DEVICE_ATTR(config_test_case, 0644, config_test_case_show,
1043                    config_test_case_store);
1044
1045 static ssize_t test_result_show(struct device *dev,
1046                                 struct device_attribute *attr,
1047                                 char *buf)
1048 {
1049         struct kmod_test_device *test_dev = dev_to_test_dev(dev);
1050         struct test_config *config = &test_dev->config;
1051
1052         return test_dev_config_show_int(test_dev, buf, config->test_result);
1053 }
1054 static DEVICE_ATTR(test_result, 0644, test_result_show, test_result_store);
1055
1056 #define TEST_KMOD_DEV_ATTR(name)                &dev_attr_##name.attr
1057
1058 static struct attribute *test_dev_attrs[] = {
1059         TEST_KMOD_DEV_ATTR(trigger_config),
1060         TEST_KMOD_DEV_ATTR(config),
1061         TEST_KMOD_DEV_ATTR(reset),
1062
1063         TEST_KMOD_DEV_ATTR(config_test_driver),
1064         TEST_KMOD_DEV_ATTR(config_test_fs),
1065         TEST_KMOD_DEV_ATTR(config_num_threads),
1066         TEST_KMOD_DEV_ATTR(config_test_case),
1067         TEST_KMOD_DEV_ATTR(test_result),
1068
1069         NULL,
1070 };
1071
1072 ATTRIBUTE_GROUPS(test_dev);
1073
1074 static int kmod_config_init(struct kmod_test_device *test_dev)
1075 {
1076         int ret;
1077
1078         mutex_lock(&test_dev->config_mutex);
1079         ret = __kmod_config_init(test_dev);
1080         mutex_unlock(&test_dev->config_mutex);
1081
1082         return ret;
1083 }
1084
1085 static struct kmod_test_device *alloc_test_dev_kmod(int idx)
1086 {
1087         int ret;
1088         struct kmod_test_device *test_dev;
1089         struct miscdevice *misc_dev;
1090
1091         test_dev = vzalloc(sizeof(struct kmod_test_device));
1092         if (!test_dev) {
1093                 pr_err("Cannot alloc test_dev\n");
1094                 goto err_out;
1095         }
1096
1097         mutex_init(&test_dev->config_mutex);
1098         mutex_init(&test_dev->trigger_mutex);
1099         mutex_init(&test_dev->thread_mutex);
1100
1101         init_completion(&test_dev->kthreads_done);
1102
1103         ret = kmod_config_init(test_dev);
1104         if (ret < 0) {
1105                 pr_err("Cannot alloc kmod_config_init()\n");
1106                 goto err_out_free;
1107         }
1108
1109         test_dev->dev_idx = idx;
1110         misc_dev = &test_dev->misc_dev;
1111
1112         misc_dev->minor = MISC_DYNAMIC_MINOR;
1113         misc_dev->name = kasprintf(GFP_KERNEL, "test_kmod%d", idx);
1114         if (!misc_dev->name) {
1115                 pr_err("Cannot alloc misc_dev->name\n");
1116                 goto err_out_free_config;
1117         }
1118         misc_dev->groups = test_dev_groups;
1119
1120         return test_dev;
1121
1122 err_out_free_config:
1123         free_test_dev_info(test_dev);
1124         kmod_config_free(test_dev);
1125 err_out_free:
1126         vfree(test_dev);
1127         test_dev = NULL;
1128 err_out:
1129         return NULL;
1130 }
1131
1132 static void free_test_dev_kmod(struct kmod_test_device *test_dev)
1133 {
1134         if (test_dev) {
1135                 kfree_const(test_dev->misc_dev.name);
1136                 test_dev->misc_dev.name = NULL;
1137                 free_test_dev_info(test_dev);
1138                 kmod_config_free(test_dev);
1139                 vfree(test_dev);
1140                 test_dev = NULL;
1141         }
1142 }
1143
1144 static struct kmod_test_device *register_test_dev_kmod(void)
1145 {
1146         struct kmod_test_device *test_dev = NULL;
1147         int ret;
1148
1149         mutex_lock(&reg_dev_mutex);
1150
1151         /* int should suffice for number of devices, test for wrap */
1152         if (unlikely(num_test_devs + 1) < 0) {
1153                 pr_err("reached limit of number of test devices\n");
1154                 goto out;
1155         }
1156
1157         test_dev = alloc_test_dev_kmod(num_test_devs);
1158         if (!test_dev)
1159                 goto out;
1160
1161         ret = misc_register(&test_dev->misc_dev);
1162         if (ret) {
1163                 pr_err("could not register misc device: %d\n", ret);
1164                 free_test_dev_kmod(test_dev);
1165                 goto out;
1166         }
1167
1168         test_dev->dev = test_dev->misc_dev.this_device;
1169         list_add_tail(&test_dev->list, &reg_test_devs);
1170         dev_info(test_dev->dev, "interface ready\n");
1171
1172         num_test_devs++;
1173
1174 out:
1175         mutex_unlock(&reg_dev_mutex);
1176
1177         return test_dev;
1178
1179 }
1180
1181 static int __init test_kmod_init(void)
1182 {
1183         struct kmod_test_device *test_dev;
1184         int ret;
1185
1186         test_dev = register_test_dev_kmod();
1187         if (!test_dev) {
1188                 pr_err("Cannot add first test kmod device\n");
1189                 return -ENODEV;
1190         }
1191
1192         /*
1193          * With some work we might be able to gracefully enable
1194          * testing with this driver built-in, for now this seems
1195          * rather risky. For those willing to try have at it,
1196          * and enable the below. Good luck! If that works, try
1197          * lowering the init level for more fun.
1198          */
1199         if (force_init_test) {
1200                 ret = trigger_config_run_type(test_dev,
1201                                               TEST_KMOD_DRIVER, "tun");
1202                 if (WARN_ON(ret))
1203                         return ret;
1204                 ret = trigger_config_run_type(test_dev,
1205                                               TEST_KMOD_FS_TYPE, "btrfs");
1206                 if (WARN_ON(ret))
1207                         return ret;
1208         }
1209
1210         return 0;
1211 }
1212 late_initcall(test_kmod_init);
1213
1214 static
1215 void unregister_test_dev_kmod(struct kmod_test_device *test_dev)
1216 {
1217         mutex_lock(&test_dev->trigger_mutex);
1218         mutex_lock(&test_dev->config_mutex);
1219
1220         test_dev_kmod_stop_tests(test_dev);
1221
1222         dev_info(test_dev->dev, "removing interface\n");
1223         misc_deregister(&test_dev->misc_dev);
1224         kfree(&test_dev->misc_dev.name);
1225
1226         mutex_unlock(&test_dev->config_mutex);
1227         mutex_unlock(&test_dev->trigger_mutex);
1228
1229         free_test_dev_kmod(test_dev);
1230 }
1231
1232 static void __exit test_kmod_exit(void)
1233 {
1234         struct kmod_test_device *test_dev, *tmp;
1235
1236         mutex_lock(&reg_dev_mutex);
1237         list_for_each_entry_safe(test_dev, tmp, &reg_test_devs, list) {
1238                 list_del(&test_dev->list);
1239                 unregister_test_dev_kmod(test_dev);
1240         }
1241         mutex_unlock(&reg_dev_mutex);
1242 }
1243 module_exit(test_kmod_exit);
1244
1245 MODULE_AUTHOR("Luis R. Rodriguez <mcgrof@kernel.org>");
1246 MODULE_LICENSE("GPL");