kernel/locking/locktorture.c

   1 /*
   2  * Module-based torture test facility for locking
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, you can access it online at
  16  * http://www.gnu.org/licenses/gpl-2.0.html.
  17  *
  18  * Copyright (C) IBM Corporation, 2014
  19  *
  20  * Author: Paul E. McKenney <paulmck@us.ibm.com>
  21  *      Based on kernel/rcu/torture.c.
  22  */
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/kthread.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/rwlock.h>
  28 #include <linux/mutex.h>
  29 #include <linux/rwsem.h>
  30 #include <linux/smp.h>
  31 #include <linux/interrupt.h>
  32 #include <linux/sched.h>
  33 #include <linux/atomic.h>
  34 #include <linux/moduleparam.h>
  35 #include <linux/delay.h>
  36 #include <linux/slab.h>
  37 #include <linux/torture.h>
  38
  39 MODULE_LICENSE("GPL");
  40 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
  41
  42 torture_param(int, nwriters_stress, -1,
  43              "Number of write-locking stress-test threads");
  44 torture_param(int, nreaders_stress, -1,
  45              "Number of read-locking stress-test threads");
  46 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
  47 torture_param(int, onoff_interval, 0,
  48              "Time between CPU hotplugs (s), 0=disable");
  49 torture_param(int, shuffle_interval, 3,
  50              "Number of jiffies between shuffles, 0=disable");
  51 torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable.");
  52 torture_param(int, stat_interval, 60,
  53              "Number of seconds between stats printk()s");
  54 torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
  55 torture_param(bool, verbose, true,
  56              "Enable verbose debugging printk()s");
  57
  58 static char *torture_type = "spin_lock";
  59 module_param(torture_type, charp, 0444);
  60 MODULE_PARM_DESC(torture_type,
  61                  "Type of lock to torture (spin_lock, spin_lock_irq, mutex_lock, ...)");
  62
  63 static struct task_struct *stats_task;
  64 static struct task_struct **writer_tasks;
  65 static struct task_struct **reader_tasks;
  66
  67 static bool lock_is_write_held;
  68 static bool lock_is_read_held;
  69
  70 struct lock_stress_stats {
  71         long n_lock_fail;
  72         long n_lock_acquired;
  73 };
  74
  75 #if defined(MODULE)
  76 #define LOCKTORTURE_RUNNABLE_INIT 1
  77 #else
  78 #define LOCKTORTURE_RUNNABLE_INIT 0
  79 #endif
  80 int torture_runnable = LOCKTORTURE_RUNNABLE_INIT;
  81 module_param(torture_runnable, int, 0444);
  82 MODULE_PARM_DESC(torture_runnable, "Start locktorture at module init");
  83
  84 /* Forward reference. */
  85 static void lock_torture_cleanup(void);
  86
  87 /*
  88  * Operations vector for selecting different types of tests.
  89  */
  90 struct lock_torture_ops {
  91         void (*init)(void);
  92         int (*writelock)(void);
  93         void (*write_delay)(struct torture_random_state *trsp);
  94         void (*writeunlock)(void);
  95         int (*readlock)(void);
  96         void (*read_delay)(struct torture_random_state *trsp);
  97         void (*readunlock)(void);
  98         unsigned long flags;
  99         const char *name;
 100 };
 101
 102 struct lock_torture_cxt {
 103         int nrealwriters_stress;
 104         int nrealreaders_stress;
 105         bool debug_lock;
 106         atomic_t n_lock_torture_errors;
 107         struct lock_torture_ops *cur_ops;
 108         struct lock_stress_stats *lwsa; /* writer statistics */
 109         struct lock_stress_stats *lrsa; /* reader statistics */
 110 };
 111 static struct lock_torture_cxt cxt = { 0, 0, false,
 112                                        ATOMIC_INIT(0),
 113                                        NULL, NULL};
 114 /*
 115  * Definitions for lock torture testing.
 116  */
 117
 118 static int torture_lock_busted_write_lock(void)
 119 {
 120         return 0;  /* BUGGY, do not use in real life!!! */
 121 }
 122
 123 static void torture_lock_busted_write_delay(struct torture_random_state *trsp)
 124 {
 125         const unsigned long longdelay_ms = 100;
 126
 127         /* We want a long delay occasionally to force massive contention.  */
 128         if (!(torture_random(trsp) %
 129               (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
 130                 mdelay(longdelay_ms);
 131 #ifdef CONFIG_PREEMPT
 132         if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
 133                 preempt_schedule();  /* Allow test to be preempted. */
 134 #endif
 135 }
 136
 137 static void torture_lock_busted_write_unlock(void)
 138 {
 139           /* BUGGY, do not use in real life!!! */
 140 }
 141
 142 static struct lock_torture_ops lock_busted_ops = {
 143         .writelock      = torture_lock_busted_write_lock,
 144         .write_delay    = torture_lock_busted_write_delay,
 145         .writeunlock    = torture_lock_busted_write_unlock,
 146         .readlock       = NULL,
 147         .read_delay     = NULL,
 148         .readunlock     = NULL,
 149         .name           = "lock_busted"
 150 };
 151
 152 static DEFINE_SPINLOCK(torture_spinlock);
 153
 154 static int torture_spin_lock_write_lock(void) __acquires(torture_spinlock)
 155 {
 156         spin_lock(&torture_spinlock);
 157         return 0;
 158 }
 159
 160 static void torture_spin_lock_write_delay(struct torture_random_state *trsp)
 161 {
 162         const unsigned long shortdelay_us = 2;
 163         const unsigned long longdelay_ms = 100;
 164
 165         /* We want a short delay mostly to emulate likely code, and
 166          * we want a long delay occasionally to force massive contention.
 167          */
 168         if (!(torture_random(trsp) %
 169               (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
 170                 mdelay(longdelay_ms);
 171         if (!(torture_random(trsp) %
 172               (cxt.nrealwriters_stress * 2 * shortdelay_us)))
 173                 udelay(shortdelay_us);
 174 #ifdef CONFIG_PREEMPT
 175         if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
 176                 preempt_schedule();  /* Allow test to be preempted. */
 177 #endif
 178 }
 179
 180 static void torture_spin_lock_write_unlock(void) __releases(torture_spinlock)
 181 {
 182         spin_unlock(&torture_spinlock);
 183 }
 184
 185 static struct lock_torture_ops spin_lock_ops = {
 186         .writelock      = torture_spin_lock_write_lock,
 187         .write_delay    = torture_spin_lock_write_delay,
 188         .writeunlock    = torture_spin_lock_write_unlock,
 189         .readlock       = NULL,
 190         .read_delay     = NULL,
 191         .readunlock     = NULL,
 192         .name           = "spin_lock"
 193 };
 194
 195 static int torture_spin_lock_write_lock_irq(void)
 196 __acquires(torture_spinlock)
 197 {
 198         unsigned long flags;
 199
 200         spin_lock_irqsave(&torture_spinlock, flags);
 201         cxt.cur_ops->flags = flags;
 202         return 0;
 203 }
 204
 205 static void torture_lock_spin_write_unlock_irq(void)
 206 __releases(torture_spinlock)
 207 {
 208         spin_unlock_irqrestore(&torture_spinlock, cxt.cur_ops->flags);
 209 }
 210
 211 static struct lock_torture_ops spin_lock_irq_ops = {
 212         .writelock      = torture_spin_lock_write_lock_irq,
 213         .write_delay    = torture_spin_lock_write_delay,
 214         .writeunlock    = torture_lock_spin_write_unlock_irq,
 215         .readlock       = NULL,
 216         .read_delay     = NULL,
 217         .readunlock     = NULL,
 218         .name           = "spin_lock_irq"
 219 };
 220
 221 static DEFINE_RWLOCK(torture_rwlock);
 222
 223 static int torture_rwlock_write_lock(void) __acquires(torture_rwlock)
 224 {
 225         write_lock(&torture_rwlock);
 226         return 0;
 227 }
 228
 229 static void torture_rwlock_write_delay(struct torture_random_state *trsp)
 230 {
 231         const unsigned long shortdelay_us = 2;
 232         const unsigned long longdelay_ms = 100;
 233
 234         /* We want a short delay mostly to emulate likely code, and
 235          * we want a long delay occasionally to force massive contention.
 236          */
 237         if (!(torture_random(trsp) %
 238               (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
 239                 mdelay(longdelay_ms);
 240         else
 241                 udelay(shortdelay_us);
 242 }
 243
 244 static void torture_rwlock_write_unlock(void) __releases(torture_rwlock)
 245 {
 246         write_unlock(&torture_rwlock);
 247 }
 248
 249 static int torture_rwlock_read_lock(void) __acquires(torture_rwlock)
 250 {
 251         read_lock(&torture_rwlock);
 252         return 0;
 253 }
 254
 255 static void torture_rwlock_read_delay(struct torture_random_state *trsp)
 256 {
 257         const unsigned long shortdelay_us = 10;
 258         const unsigned long longdelay_ms = 100;
 259
 260         /* We want a short delay mostly to emulate likely code, and
 261          * we want a long delay occasionally to force massive contention.
 262          */
 263         if (!(torture_random(trsp) %
 264               (cxt.nrealreaders_stress * 2000 * longdelay_ms)))
 265                 mdelay(longdelay_ms);
 266         else
 267                 udelay(shortdelay_us);
 268 }
 269
 270 static void torture_rwlock_read_unlock(void) __releases(torture_rwlock)
 271 {
 272         read_unlock(&torture_rwlock);
 273 }
 274
 275 static struct lock_torture_ops rw_lock_ops = {
 276         .writelock      = torture_rwlock_write_lock,
 277         .write_delay    = torture_rwlock_write_delay,
 278         .writeunlock    = torture_rwlock_write_unlock,
 279         .readlock       = torture_rwlock_read_lock,
 280         .read_delay     = torture_rwlock_read_delay,
 281         .readunlock     = torture_rwlock_read_unlock,
 282         .name           = "rw_lock"
 283 };
 284
 285 static int torture_rwlock_write_lock_irq(void) __acquires(torture_rwlock)
 286 {
 287         unsigned long flags;
 288
 289         write_lock_irqsave(&torture_rwlock, flags);
 290         cxt.cur_ops->flags = flags;
 291         return 0;
 292 }
 293
 294 static void torture_rwlock_write_unlock_irq(void)
 295 __releases(torture_rwlock)
 296 {
 297         write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
 298 }
 299
 300 static int torture_rwlock_read_lock_irq(void) __acquires(torture_rwlock)
 301 {
 302         unsigned long flags;
 303
 304         read_lock_irqsave(&torture_rwlock, flags);
 305         cxt.cur_ops->flags = flags;
 306         return 0;
 307 }
 308
 309 static void torture_rwlock_read_unlock_irq(void)
 310 __releases(torture_rwlock)
 311 {
 312         read_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
 313 }
 314
 315 static struct lock_torture_ops rw_lock_irq_ops = {
 316         .writelock      = torture_rwlock_write_lock_irq,
 317         .write_delay    = torture_rwlock_write_delay,
 318         .writeunlock    = torture_rwlock_write_unlock_irq,
 319         .readlock       = torture_rwlock_read_lock_irq,
 320         .read_delay     = torture_rwlock_read_delay,
 321         .readunlock     = torture_rwlock_read_unlock_irq,
 322         .name           = "rw_lock_irq"
 323 };
 324
 325 static DEFINE_MUTEX(torture_mutex);
 326
 327 static int torture_mutex_lock(void) __acquires(torture_mutex)
 328 {
 329         mutex_lock(&torture_mutex);
 330         return 0;
 331 }
 332
 333 static void torture_mutex_delay(struct torture_random_state *trsp)
 334 {
 335         const unsigned long longdelay_ms = 100;
 336
 337         /* We want a long delay occasionally to force massive contention.  */
 338         if (!(torture_random(trsp) %
 339               (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
 340                 mdelay(longdelay_ms * 5);
 341         else
 342                 mdelay(longdelay_ms / 5);
 343 #ifdef CONFIG_PREEMPT
 344         if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
 345                 preempt_schedule();  /* Allow test to be preempted. */
 346 #endif
 347 }
 348
 349 static void torture_mutex_unlock(void) __releases(torture_mutex)
 350 {
 351         mutex_unlock(&torture_mutex);
 352 }
 353
 354 static struct lock_torture_ops mutex_lock_ops = {
 355         .writelock      = torture_mutex_lock,
 356         .write_delay    = torture_mutex_delay,
 357         .writeunlock    = torture_mutex_unlock,
 358         .readlock       = NULL,
 359         .read_delay     = NULL,
 360         .readunlock     = NULL,
 361         .name           = "mutex_lock"
 362 };
 363
 364 static DECLARE_RWSEM(torture_rwsem);
 365 static int torture_rwsem_down_write(void) __acquires(torture_rwsem)
 366 {
 367         down_write(&torture_rwsem);
 368         return 0;
 369 }
 370
 371 static void torture_rwsem_write_delay(struct torture_random_state *trsp)
 372 {
 373         const unsigned long longdelay_ms = 100;
 374
 375         /* We want a long delay occasionally to force massive contention.  */
 376         if (!(torture_random(trsp) %
 377               (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
 378                 mdelay(longdelay_ms * 10);
 379         else
 380                 mdelay(longdelay_ms / 10);
 381 #ifdef CONFIG_PREEMPT
 382         if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
 383                 preempt_schedule();  /* Allow test to be preempted. */
 384 #endif
 385 }
 386
 387 static void torture_rwsem_up_write(void) __releases(torture_rwsem)
 388 {
 389         up_write(&torture_rwsem);
 390 }
 391
 392 static int torture_rwsem_down_read(void) __acquires(torture_rwsem)
 393 {
 394         down_read(&torture_rwsem);
 395         return 0;
 396 }
 397
 398 static void torture_rwsem_read_delay(struct torture_random_state *trsp)
 399 {
 400         const unsigned long longdelay_ms = 100;
 401
 402         /* We want a long delay occasionally to force massive contention.  */
 403         if (!(torture_random(trsp) %
 404               (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
 405                 mdelay(longdelay_ms * 2);
 406         else
 407                 mdelay(longdelay_ms / 2);
 408 #ifdef CONFIG_PREEMPT
 409         if (!(torture_random(trsp) % (cxt.nrealreaders_stress * 20000)))
 410                 preempt_schedule();  /* Allow test to be preempted. */
 411 #endif
 412 }
 413
 414 static void torture_rwsem_up_read(void) __releases(torture_rwsem)
 415 {
 416         up_read(&torture_rwsem);
 417 }
 418
 419 static struct lock_torture_ops rwsem_lock_ops = {
 420         .writelock      = torture_rwsem_down_write,
 421         .write_delay    = torture_rwsem_write_delay,
 422         .writeunlock    = torture_rwsem_up_write,
 423         .readlock       = torture_rwsem_down_read,
 424         .read_delay     = torture_rwsem_read_delay,
 425         .readunlock     = torture_rwsem_up_read,
 426         .name           = "rwsem_lock"
 427 };
 428
 429 /*
 430  * Lock torture writer kthread.  Repeatedly acquires and releases
 431  * the lock, checking for duplicate acquisitions.
 432  */
 433 static int lock_torture_writer(void *arg)
 434 {
 435         struct lock_stress_stats *lwsp = arg;
 436         static DEFINE_TORTURE_RANDOM(rand);
 437
 438         VERBOSE_TOROUT_STRING("lock_torture_writer task started");
 439         set_user_nice(current, MAX_NICE);
 440
 441         do {
 442                 if ((torture_random(&rand) & 0xfffff) == 0)
 443                         schedule_timeout_uninterruptible(1);
 444
 445                 cxt.cur_ops->writelock();
 446                 if (WARN_ON_ONCE(lock_is_write_held))
 447                         lwsp->n_lock_fail++;
 448                 lock_is_write_held = 1;
 449                 if (WARN_ON_ONCE(lock_is_read_held))
 450                         lwsp->n_lock_fail++; /* rare, but... */
 451
 452                 lwsp->n_lock_acquired++;
 453                 cxt.cur_ops->write_delay(&rand);
 454                 lock_is_write_held = 0;
 455                 cxt.cur_ops->writeunlock();
 456
 457                 stutter_wait("lock_torture_writer");
 458         } while (!torture_must_stop());
 459         torture_kthread_stopping("lock_torture_writer");
 460         return 0;
 461 }
 462
 463 /*
 464  * Lock torture reader kthread.  Repeatedly acquires and releases
 465  * the reader lock.
 466  */
 467 static int lock_torture_reader(void *arg)
 468 {
 469         struct lock_stress_stats *lrsp = arg;
 470         static DEFINE_TORTURE_RANDOM(rand);
 471
 472         VERBOSE_TOROUT_STRING("lock_torture_reader task started");
 473         set_user_nice(current, MAX_NICE);
 474
 475         do {
 476                 if ((torture_random(&rand) & 0xfffff) == 0)
 477                         schedule_timeout_uninterruptible(1);
 478
 479                 cxt.cur_ops->readlock();
 480                 lock_is_read_held = 1;
 481                 if (WARN_ON_ONCE(lock_is_write_held))
 482                         lrsp->n_lock_fail++; /* rare, but... */
 483
 484                 lrsp->n_lock_acquired++;
 485                 cxt.cur_ops->read_delay(&rand);
 486                 lock_is_read_held = 0;
 487                 cxt.cur_ops->readunlock();
 488
 489                 stutter_wait("lock_torture_reader");
 490         } while (!torture_must_stop());
 491         torture_kthread_stopping("lock_torture_reader");
 492         return 0;
 493 }
 494
 495 /*
 496  * Create an lock-torture-statistics message in the specified buffer.
 497  */
 498 static void __torture_print_stats(char *page,
 499                                   struct lock_stress_stats *statp, bool write)
 500 {
 501         bool fail = 0;
 502         int i, n_stress;
 503         long max = 0;
 504         long min = statp[0].n_lock_acquired;
 505         long long sum = 0;
 506
 507         n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress;
 508         for (i = 0; i < n_stress; i++) {
 509                 if (statp[i].n_lock_fail)
 510                         fail = true;
 511                 sum += statp[i].n_lock_acquired;
 512                 if (max < statp[i].n_lock_fail)
 513                         max = statp[i].n_lock_fail;
 514                 if (min > statp[i].n_lock_fail)
 515                         min = statp[i].n_lock_fail;
 516         }
 517         page += sprintf(page,
 518                         "%s:  Total: %lld  Max/Min: %ld/%ld %s  Fail: %d %s\n",
 519                         write ? "Writes" : "Reads ",
 520                         sum, max, min, max / 2 > min ? "???" : "",
 521                         fail, fail ? "!!!" : "");
 522         if (fail)
 523                 atomic_inc(&cxt.n_lock_torture_errors);
 524 }
 525
 526 /*
 527  * Print torture statistics.  Caller must ensure that there is only one
 528  * call to this function at a given time!!!  This is normally accomplished
 529  * by relying on the module system to only have one copy of the module
 530  * loaded, and then by giving the lock_torture_stats kthread full control
 531  * (or the init/cleanup functions when lock_torture_stats thread is not
 532  * running).
 533  */
 534 static void lock_torture_stats_print(void)
 535 {
 536         int size = cxt.nrealwriters_stress * 200 + 8192;
 537         char *buf;
 538
 539         if (cxt.cur_ops->readlock)
 540                 size += cxt.nrealreaders_stress * 200 + 8192;
 541
 542         buf = kmalloc(size, GFP_KERNEL);
 543         if (!buf) {
 544                 pr_err("lock_torture_stats_print: Out of memory, need: %d",
 545                        size);
 546                 return;
 547         }
 548
 549         __torture_print_stats(buf, cxt.lwsa, true);
 550         pr_alert("%s", buf);
 551         kfree(buf);
 552
 553         if (cxt.cur_ops->readlock) {
 554                 buf = kmalloc(size, GFP_KERNEL);
 555                 if (!buf) {
 556                         pr_err("lock_torture_stats_print: Out of memory, need: %d",
 557                                size);
 558                         return;
 559                 }
 560
 561                 __torture_print_stats(buf, cxt.lrsa, false);
 562                 pr_alert("%s", buf);
 563                 kfree(buf);
 564         }
 565 }
 566
 567 /*
 568  * Periodically prints torture statistics, if periodic statistics printing
 569  * was specified via the stat_interval module parameter.
 570  *
 571  * No need to worry about fullstop here, since this one doesn't reference
 572  * volatile state or register callbacks.
 573  */
 574 static int lock_torture_stats(void *arg)
 575 {
 576         VERBOSE_TOROUT_STRING("lock_torture_stats task started");
 577         do {
 578                 schedule_timeout_interruptible(stat_interval * HZ);
 579                 lock_torture_stats_print();
 580                 torture_shutdown_absorb("lock_torture_stats");
 581         } while (!torture_must_stop());
 582         torture_kthread_stopping("lock_torture_stats");
 583         return 0;
 584 }
 585
 586 static inline void
 587 lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
 588                                 const char *tag)
 589 {
 590         pr_alert("%s" TORTURE_FLAG
 591                  "--- %s%s: nwriters_stress=%d nreaders_stress=%d stat_interval=%d verbose=%d shuffle_interval=%d stutter=%d shutdown_secs=%d onoff_interval=%d onoff_holdoff=%d\n",
 592                  torture_type, tag, cxt.debug_lock ? " [debug]": "",
 593                  cxt.nrealwriters_stress, cxt.nrealreaders_stress, stat_interval,
 594                  verbose, shuffle_interval, stutter, shutdown_secs,
 595                  onoff_interval, onoff_holdoff);
 596 }
 597
 598 static void lock_torture_cleanup(void)
 599 {
 600         int i;
 601
 602         if (torture_cleanup_begin())
 603                 return;
 604
 605         if (writer_tasks) {
 606                 for (i = 0; i < cxt.nrealwriters_stress; i++)
 607                         torture_stop_kthread(lock_torture_writer,
 608                                              writer_tasks[i]);
 609                 kfree(writer_tasks);
 610                 writer_tasks = NULL;
 611         }
 612
 613         if (reader_tasks) {
 614                 for (i = 0; i < cxt.nrealreaders_stress; i++)
 615                         torture_stop_kthread(lock_torture_reader,
 616                                              reader_tasks[i]);
 617                 kfree(reader_tasks);
 618                 reader_tasks = NULL;
 619         }
 620
 621         torture_stop_kthread(lock_torture_stats, stats_task);
 622         lock_torture_stats_print();  /* -After- the stats thread is stopped! */
 623
 624         if (atomic_read(&cxt.n_lock_torture_errors))
 625                 lock_torture_print_module_parms(cxt.cur_ops,
 626                                                 "End of test: FAILURE");
 627         else if (torture_onoff_failures())
 628                 lock_torture_print_module_parms(cxt.cur_ops,
 629                                                 "End of test: LOCK_HOTPLUG");
 630         else
 631                 lock_torture_print_module_parms(cxt.cur_ops,
 632                                                 "End of test: SUCCESS");
 633         torture_cleanup_end();
 634 }
 635
 636 static int __init lock_torture_init(void)
 637 {
 638         int i, j;
 639         int firsterr = 0;
 640         static struct lock_torture_ops *torture_ops[] = {
 641                 &lock_busted_ops,
 642                 &spin_lock_ops, &spin_lock_irq_ops,
 643                 &rw_lock_ops, &rw_lock_irq_ops,
 644                 &mutex_lock_ops,
 645                 &rwsem_lock_ops,
 646         };
 647
 648         if (!torture_init_begin(torture_type, verbose, &torture_runnable))
 649                 return -EBUSY;
 650
 651         /* Process args and tell the world that the torturer is on the job. */
 652         for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
 653                 cxt.cur_ops = torture_ops[i];
 654                 if (strcmp(torture_type, cxt.cur_ops->name) == 0)
 655                         break;
 656         }
 657         if (i == ARRAY_SIZE(torture_ops)) {
 658                 pr_alert("lock-torture: invalid torture type: \"%s\"\n",
 659                          torture_type);
 660                 pr_alert("lock-torture types:");
 661                 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
 662                         pr_alert(" %s", torture_ops[i]->name);
 663                 pr_alert("\n");
 664                 torture_init_end();
 665                 return -EINVAL;
 666         }
 667         if (cxt.cur_ops->init)
 668                 cxt.cur_ops->init(); /* no "goto unwind" prior to this point!!! */
 669
 670         if (nwriters_stress >= 0)
 671                 cxt.nrealwriters_stress = nwriters_stress;
 672         else
 673                 cxt.nrealwriters_stress = 2 * num_online_cpus();
 674
 675 #ifdef CONFIG_DEBUG_MUTEXES
 676         if (strncmp(torture_type, "mutex", 5) == 0)
 677                 cxt.debug_lock = true;
 678 #endif
 679 #ifdef CONFIG_DEBUG_SPINLOCK
 680         if ((strncmp(torture_type, "spin", 4) == 0) ||
 681             (strncmp(torture_type, "rw_lock", 7) == 0))
 682                 cxt.debug_lock = true;
 683 #endif
 684
 685         /* Initialize the statistics so that each run gets its own numbers. */
 686
 687         lock_is_write_held = 0;
 688         cxt.lwsa = kmalloc(sizeof(*cxt.lwsa) * cxt.nrealwriters_stress, GFP_KERNEL);
 689         if (cxt.lwsa == NULL) {
 690                 VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory");
 691                 firsterr = -ENOMEM;
 692                 goto unwind;
 693         }
 694         for (i = 0; i < cxt.nrealwriters_stress; i++) {
 695                 cxt.lwsa[i].n_lock_fail = 0;
 696                 cxt.lwsa[i].n_lock_acquired = 0;
 697         }
 698
 699         if (cxt.cur_ops->readlock) {
 700                 if (nreaders_stress >= 0)
 701                         cxt.nrealreaders_stress = nreaders_stress;
 702                 else {
 703                         /*
 704                          * By default distribute evenly the number of
 705                          * readers and writers. We still run the same number
 706                          * of threads as the writer-only locks default.
 707                          */
 708                         if (nwriters_stress < 0) /* user doesn't care */
 709                                 cxt.nrealwriters_stress = num_online_cpus();
 710                         cxt.nrealreaders_stress = cxt.nrealwriters_stress;
 711                 }
 712
 713                 lock_is_read_held = 0;
 714                 cxt.lrsa = kmalloc(sizeof(*cxt.lrsa) * cxt.nrealreaders_stress, GFP_KERNEL);
 715                 if (cxt.lrsa == NULL) {
 716                         VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory");
 717                         firsterr = -ENOMEM;
 718                         kfree(cxt.lwsa);
 719                         goto unwind;
 720                 }
 721
 722                 for (i = 0; i < cxt.nrealreaders_stress; i++) {
 723                         cxt.lrsa[i].n_lock_fail = 0;
 724                         cxt.lrsa[i].n_lock_acquired = 0;
 725                 }
 726         }
 727         lock_torture_print_module_parms(cxt.cur_ops, "Start of test");
 728
 729         /* Prepare torture context. */
 730         if (onoff_interval > 0) {
 731                 firsterr = torture_onoff_init(onoff_holdoff * HZ,
 732                                               onoff_interval * HZ);
 733                 if (firsterr)
 734                         goto unwind;
 735         }
 736         if (shuffle_interval > 0) {
 737                 firsterr = torture_shuffle_init(shuffle_interval);
 738                 if (firsterr)
 739                         goto unwind;
 740         }
 741         if (shutdown_secs > 0) {
 742                 firsterr = torture_shutdown_init(shutdown_secs,
 743                                                  lock_torture_cleanup);
 744                 if (firsterr)
 745                         goto unwind;
 746         }
 747         if (stutter > 0) {
 748                 firsterr = torture_stutter_init(stutter);
 749                 if (firsterr)
 750                         goto unwind;
 751         }
 752
 753         writer_tasks = kzalloc(cxt.nrealwriters_stress * sizeof(writer_tasks[0]),
 754                                GFP_KERNEL);
 755         if (writer_tasks == NULL) {
 756                 VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory");
 757                 firsterr = -ENOMEM;
 758                 goto unwind;
 759         }
 760
 761         if (cxt.cur_ops->readlock) {
 762                 reader_tasks = kzalloc(cxt.nrealreaders_stress * sizeof(reader_tasks[0]),
 763                                        GFP_KERNEL);
 764                 if (reader_tasks == NULL) {
 765                         VERBOSE_TOROUT_ERRSTRING("reader_tasks: Out of memory");
 766                         firsterr = -ENOMEM;
 767                         goto unwind;
 768                 }
 769         }
 770
 771         /*
 772          * Create the kthreads and start torturing (oh, those poor little locks).
 773          *
 774          * TODO: Note that we interleave writers with readers, giving writers a
 775          * slight advantage, by creating its kthread first. This can be modified
 776          * for very specific needs, or even let the user choose the policy, if
 777          * ever wanted.
 778          */
 779         for (i = 0, j = 0; i < cxt.nrealwriters_stress ||
 780                     j < cxt.nrealreaders_stress; i++, j++) {
 781                 if (i >= cxt.nrealwriters_stress)
 782                         goto create_reader;
 783
 784                 /* Create writer. */
 785                 firsterr = torture_create_kthread(lock_torture_writer, &cxt.lwsa[i],
 786                                                   writer_tasks[i]);
 787                 if (firsterr)
 788                         goto unwind;
 789
 790         create_reader:
 791                 if (cxt.cur_ops->readlock == NULL || (j >= cxt.nrealreaders_stress))
 792                         continue;
 793                 /* Create reader. */
 794                 firsterr = torture_create_kthread(lock_torture_reader, &cxt.lrsa[j],
 795                                                   reader_tasks[j]);
 796                 if (firsterr)
 797                         goto unwind;
 798         }
 799         if (stat_interval > 0) {
 800                 firsterr = torture_create_kthread(lock_torture_stats, NULL,
 801                                                   stats_task);
 802                 if (firsterr)
 803                         goto unwind;
 804         }
 805         torture_init_end();
 806         return 0;
 807
 808 unwind:
 809         torture_init_end();
 810         lock_torture_cleanup();
 811         return firsterr;
 812 }
 813
 814 module_init(lock_torture_init);
 815 module_exit(lock_torture_cleanup);