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/types.h>
  24 #include <linux/kernel.h>
  25 #include <linux/init.h>
  26 #include <linux/module.h>
  27 #include <linux/kthread.h>
  28 #include <linux/err.h>
  29 #include <linux/spinlock.h>
  30 #include <linux/rwlock.h>
  31 #include <linux/mutex.h>
  32 #include <linux/smp.h>
  33 #include <linux/interrupt.h>
  34 #include <linux/sched.h>
  35 #include <linux/atomic.h>
  36 #include <linux/bitops.h>
  37 #include <linux/completion.h>
  38 #include <linux/moduleparam.h>
  39 #include <linux/percpu.h>
  40 #include <linux/notifier.h>
  41 #include <linux/reboot.h>
  42 #include <linux/freezer.h>
  43 #include <linux/cpu.h>
  44 #include <linux/delay.h>
  45 #include <linux/stat.h>
  46 #include <linux/slab.h>
  47 #include <linux/trace_clock.h>
  48 #include <asm/byteorder.h>
  49 #include <linux/torture.h>
  50
  51 MODULE_LICENSE("GPL");
  52 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
  53
  54 torture_param(int, nwriters_stress, -1,
  55              "Number of write-locking stress-test threads");
  56 torture_param(int, nreaders_stress, -1,
  57              "Number of read-locking stress-test threads");
  58 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
  59 torture_param(int, onoff_interval, 0,
  60              "Time between CPU hotplugs (s), 0=disable");
  61 torture_param(int, shuffle_interval, 3,
  62              "Number of jiffies between shuffles, 0=disable");
  63 torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable.");
  64 torture_param(int, stat_interval, 60,
  65              "Number of seconds between stats printk()s");
  66 torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
  67 torture_param(bool, verbose, true,
  68              "Enable verbose debugging printk()s");
  69
  70 static char *torture_type = "spin_lock";
  71 module_param(torture_type, charp, 0444);
  72 MODULE_PARM_DESC(torture_type,
  73                  "Type of lock to torture (spin_lock, spin_lock_irq, mutex_lock, ...)");
  74
  75 static struct task_struct *stats_task;
  76 static struct task_struct **writer_tasks;
  77 static struct task_struct **reader_tasks;
  78
  79 static bool lock_is_write_held;
  80 static bool lock_is_read_held;
  81
  82 struct lock_stress_stats {
  83         long n_lock_fail;
  84         long n_lock_acquired;
  85 };
  86
  87 #if defined(MODULE)
  88 #define LOCKTORTURE_RUNNABLE_INIT 1
  89 #else
  90 #define LOCKTORTURE_RUNNABLE_INIT 0
  91 #endif
  92 int torture_runnable = LOCKTORTURE_RUNNABLE_INIT;
  93 module_param(torture_runnable, int, 0444);
  94 MODULE_PARM_DESC(torture_runnable, "Start locktorture at module init");
  95
  96 /* Forward reference. */
  97 static void lock_torture_cleanup(void);
  98
  99 /*
 100  * Operations vector for selecting different types of tests.
 101  */
 102 struct lock_torture_ops {
 103         void (*init)(void);
 104         int (*writelock)(void);
 105         void (*write_delay)(struct torture_random_state *trsp);
 106         void (*writeunlock)(void);
 107         int (*readlock)(void);
 108         void (*read_delay)(struct torture_random_state *trsp);
 109         void (*readunlock)(void);
 110         unsigned long flags;
 111         const char *name;
 112 };
 113
 114 struct lock_torture_cxt {
 115         int nrealwriters_stress;
 116         int nrealreaders_stress;
 117         bool debug_lock;
 118         atomic_t n_lock_torture_errors;
 119         struct lock_torture_ops *cur_ops;
 120         struct lock_stress_stats *lwsa; /* writer statistics */
 121         struct lock_stress_stats *lrsa; /* reader statistics */
 122 };
 123 static struct lock_torture_cxt cxt = { 0, 0, false,
 124                                        ATOMIC_INIT(0),
 125                                        NULL, NULL};
 126 /*
 127  * Definitions for lock torture testing.
 128  */
 129
 130 static int torture_lock_busted_write_lock(void)
 131 {
 132         return 0;  /* BUGGY, do not use in real life!!! */
 133 }
 134
 135 static void torture_lock_busted_write_delay(struct torture_random_state *trsp)
 136 {
 137         const unsigned long longdelay_us = 100;
 138
 139         /* We want a long delay occasionally to force massive contention.  */
 140         if (!(torture_random(trsp) %
 141               (cxt.nrealwriters_stress * 2000 * longdelay_us)))
 142                 mdelay(longdelay_us);
 143 #ifdef CONFIG_PREEMPT
 144         if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
 145                 preempt_schedule();  /* Allow test to be preempted. */
 146 #endif
 147 }
 148
 149 static void torture_lock_busted_write_unlock(void)
 150 {
 151           /* BUGGY, do not use in real life!!! */
 152 }
 153
 154 static struct lock_torture_ops lock_busted_ops = {
 155         .writelock      = torture_lock_busted_write_lock,
 156         .write_delay    = torture_lock_busted_write_delay,
 157         .writeunlock    = torture_lock_busted_write_unlock,
 158         .readlock       = NULL,
 159         .read_delay     = NULL,
 160         .readunlock     = NULL,
 161         .name           = "lock_busted"
 162 };
 163
 164 static DEFINE_SPINLOCK(torture_spinlock);
 165
 166 static int torture_spin_lock_write_lock(void) __acquires(torture_spinlock)
 167 {
 168         spin_lock(&torture_spinlock);
 169         return 0;
 170 }
 171
 172 static void torture_spin_lock_write_delay(struct torture_random_state *trsp)
 173 {
 174         const unsigned long shortdelay_us = 2;
 175         const unsigned long longdelay_us = 100;
 176
 177         /* We want a short delay mostly to emulate likely code, and
 178          * we want a long delay occasionally to force massive contention.
 179          */
 180         if (!(torture_random(trsp) %
 181               (cxt.nrealwriters_stress * 2000 * longdelay_us)))
 182                 mdelay(longdelay_us);
 183         if (!(torture_random(trsp) %
 184               (cxt.nrealwriters_stress * 2 * shortdelay_us)))
 185                 udelay(shortdelay_us);
 186 #ifdef CONFIG_PREEMPT
 187         if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
 188                 preempt_schedule();  /* Allow test to be preempted. */
 189 #endif
 190 }
 191
 192 static void torture_spin_lock_write_unlock(void) __releases(torture_spinlock)
 193 {
 194         spin_unlock(&torture_spinlock);
 195 }
 196
 197 static struct lock_torture_ops spin_lock_ops = {
 198         .writelock      = torture_spin_lock_write_lock,
 199         .write_delay    = torture_spin_lock_write_delay,
 200         .writeunlock    = torture_spin_lock_write_unlock,
 201         .readlock       = NULL,
 202         .read_delay     = NULL,
 203         .readunlock     = NULL,
 204         .name           = "spin_lock"
 205 };
 206
 207 static int torture_spin_lock_write_lock_irq(void)
 208 __acquires(torture_spinlock)
 209 {
 210         unsigned long flags;
 211
 212         spin_lock_irqsave(&torture_spinlock, flags);
 213         cxt.cur_ops->flags = flags;
 214         return 0;
 215 }
 216
 217 static void torture_lock_spin_write_unlock_irq(void)
 218 __releases(torture_spinlock)
 219 {
 220         spin_unlock_irqrestore(&torture_spinlock, cxt.cur_ops->flags);
 221 }
 222
 223 static struct lock_torture_ops spin_lock_irq_ops = {
 224         .writelock      = torture_spin_lock_write_lock_irq,
 225         .write_delay    = torture_spin_lock_write_delay,
 226         .writeunlock    = torture_lock_spin_write_unlock_irq,
 227         .readlock       = NULL,
 228         .read_delay     = NULL,
 229         .readunlock     = NULL,
 230         .name           = "spin_lock_irq"
 231 };
 232
 233 static DEFINE_RWLOCK(torture_rwlock);
 234
 235 static int torture_rwlock_write_lock(void) __acquires(torture_rwlock)
 236 {
 237         write_lock(&torture_rwlock);
 238         return 0;
 239 }
 240
 241 static void torture_rwlock_write_delay(struct torture_random_state *trsp)
 242 {
 243         const unsigned long shortdelay_us = 2;
 244         const unsigned long longdelay_ms = 100;
 245
 246         /* We want a short delay mostly to emulate likely code, and
 247          * we want a long delay occasionally to force massive contention.
 248          */
 249         if (!(torture_random(trsp) %
 250               (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
 251                 mdelay(longdelay_ms);
 252         else
 253                 udelay(shortdelay_us);
 254 }
 255
 256 static void torture_rwlock_write_unlock(void) __releases(torture_rwlock)
 257 {
 258         write_unlock(&torture_rwlock);
 259 }
 260
 261 static int torture_rwlock_read_lock(void) __acquires(torture_rwlock)
 262 {
 263         read_lock(&torture_rwlock);
 264         return 0;
 265 }
 266
 267 static void torture_rwlock_read_delay(struct torture_random_state *trsp)
 268 {
 269         const unsigned long shortdelay_us = 10;
 270         const unsigned long longdelay_ms = 100;
 271
 272         /* We want a short delay mostly to emulate likely code, and
 273          * we want a long delay occasionally to force massive contention.
 274          */
 275         if (!(torture_random(trsp) %
 276               (cxt.nrealreaders_stress * 2000 * longdelay_ms)))
 277                 mdelay(longdelay_ms);
 278         else
 279                 udelay(shortdelay_us);
 280 }
 281
 282 static void torture_rwlock_read_unlock(void) __releases(torture_rwlock)
 283 {
 284         read_unlock(&torture_rwlock);
 285 }
 286
 287 static struct lock_torture_ops rw_lock_ops = {
 288         .writelock      = torture_rwlock_write_lock,
 289         .write_delay    = torture_rwlock_write_delay,
 290         .writeunlock    = torture_rwlock_write_unlock,
 291         .readlock       = torture_rwlock_read_lock,
 292         .read_delay     = torture_rwlock_read_delay,
 293         .readunlock     = torture_rwlock_read_unlock,
 294         .name           = "rw_lock"
 295 };
 296
 297 static int torture_rwlock_write_lock_irq(void) __acquires(torture_rwlock)
 298 {
 299         unsigned long flags;
 300
 301         write_lock_irqsave(&torture_rwlock, flags);
 302         cxt.cur_ops->flags = flags;
 303         return 0;
 304 }
 305
 306 static void torture_rwlock_write_unlock_irq(void)
 307 __releases(torture_rwlock)
 308 {
 309         write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
 310 }
 311
 312 static int torture_rwlock_read_lock_irq(void) __acquires(torture_rwlock)
 313 {
 314         unsigned long flags;
 315
 316         read_lock_irqsave(&torture_rwlock, flags);
 317         cxt.cur_ops->flags = flags;
 318         return 0;
 319 }
 320
 321 static void torture_rwlock_read_unlock_irq(void)
 322 __releases(torture_rwlock)
 323 {
 324         write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
 325 }
 326
 327 static struct lock_torture_ops rw_lock_irq_ops = {
 328         .writelock      = torture_rwlock_write_lock_irq,
 329         .write_delay    = torture_rwlock_write_delay,
 330         .writeunlock    = torture_rwlock_write_unlock_irq,
 331         .readlock       = torture_rwlock_read_lock_irq,
 332         .read_delay     = torture_rwlock_read_delay,
 333         .readunlock     = torture_rwlock_read_unlock_irq,
 334         .name           = "rw_lock_irq"
 335 };
 336
 337 static DEFINE_MUTEX(torture_mutex);
 338
 339 static int torture_mutex_lock(void) __acquires(torture_mutex)
 340 {
 341         mutex_lock(&torture_mutex);
 342         return 0;
 343 }
 344
 345 static void torture_mutex_delay(struct torture_random_state *trsp)
 346 {
 347         const unsigned long longdelay_ms = 100;
 348
 349         /* We want a long delay occasionally to force massive contention.  */
 350         if (!(torture_random(trsp) %
 351               (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
 352                 mdelay(longdelay_ms * 5);
 353         else
 354                 mdelay(longdelay_ms / 5);
 355 #ifdef CONFIG_PREEMPT
 356         if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
 357                 preempt_schedule();  /* Allow test to be preempted. */
 358 #endif
 359 }
 360
 361 static void torture_mutex_unlock(void) __releases(torture_mutex)
 362 {
 363         mutex_unlock(&torture_mutex);
 364 }
 365
 366 static struct lock_torture_ops mutex_lock_ops = {
 367         .writelock      = torture_mutex_lock,
 368         .write_delay    = torture_mutex_delay,
 369         .writeunlock    = torture_mutex_unlock,
 370         .readlock       = NULL,
 371         .read_delay     = NULL,
 372         .readunlock     = NULL,
 373         .name           = "mutex_lock"
 374 };
 375
 376 static DECLARE_RWSEM(torture_rwsem);
 377 static int torture_rwsem_down_write(void) __acquires(torture_rwsem)
 378 {
 379         down_write(&torture_rwsem);
 380         return 0;
 381 }
 382
 383 static void torture_rwsem_write_delay(struct torture_random_state *trsp)
 384 {
 385         const unsigned long longdelay_ms = 100;
 386
 387         /* We want a long delay occasionally to force massive contention.  */
 388         if (!(torture_random(trsp) %
 389               (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
 390                 mdelay(longdelay_ms * 10);
 391         else
 392                 mdelay(longdelay_ms / 10);
 393 #ifdef CONFIG_PREEMPT
 394         if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
 395                 preempt_schedule();  /* Allow test to be preempted. */
 396 #endif
 397 }
 398
 399 static void torture_rwsem_up_write(void) __releases(torture_rwsem)
 400 {
 401         up_write(&torture_rwsem);
 402 }
 403
 404 static int torture_rwsem_down_read(void) __acquires(torture_rwsem)
 405 {
 406         down_read(&torture_rwsem);
 407         return 0;
 408 }
 409
 410 static void torture_rwsem_read_delay(struct torture_random_state *trsp)
 411 {
 412         const unsigned long longdelay_ms = 100;
 413
 414         /* We want a long delay occasionally to force massive contention.  */
 415         if (!(torture_random(trsp) %
 416               (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
 417                 mdelay(longdelay_ms * 2);
 418         else
 419                 mdelay(longdelay_ms / 2);
 420 #ifdef CONFIG_PREEMPT
 421         if (!(torture_random(trsp) % (cxt.nrealreaders_stress * 20000)))
 422                 preempt_schedule();  /* Allow test to be preempted. */
 423 #endif
 424 }
 425
 426 static void torture_rwsem_up_read(void) __releases(torture_rwsem)
 427 {
 428         up_read(&torture_rwsem);
 429 }
 430
 431 static struct lock_torture_ops rwsem_lock_ops = {
 432         .writelock      = torture_rwsem_down_write,
 433         .write_delay    = torture_rwsem_write_delay,
 434         .writeunlock    = torture_rwsem_up_write,
 435         .readlock       = torture_rwsem_down_read,
 436         .read_delay     = torture_rwsem_read_delay,
 437         .readunlock     = torture_rwsem_up_read,
 438         .name           = "rwsem_lock"
 439 };
 440
 441 /*
 442  * Lock torture writer kthread.  Repeatedly acquires and releases
 443  * the lock, checking for duplicate acquisitions.
 444  */
 445 static int lock_torture_writer(void *arg)
 446 {
 447         struct lock_stress_stats *lwsp = arg;
 448         static DEFINE_TORTURE_RANDOM(rand);
 449
 450         VERBOSE_TOROUT_STRING("lock_torture_writer task started");
 451         set_user_nice(current, MAX_NICE);
 452
 453         do {
 454                 if ((torture_random(&rand) & 0xfffff) == 0)
 455                         schedule_timeout_uninterruptible(1);
 456
 457                 cxt.cur_ops->writelock();
 458                 if (WARN_ON_ONCE(lock_is_write_held))
 459                         lwsp->n_lock_fail++;
 460                 lock_is_write_held = 1;
 461                 if (WARN_ON_ONCE(lock_is_read_held))
 462                         lwsp->n_lock_fail++; /* rare, but... */
 463
 464                 lwsp->n_lock_acquired++;
 465                 cxt.cur_ops->write_delay(&rand);
 466                 lock_is_write_held = 0;
 467                 cxt.cur_ops->writeunlock();
 468
 469                 stutter_wait("lock_torture_writer");
 470         } while (!torture_must_stop());
 471         torture_kthread_stopping("lock_torture_writer");
 472         return 0;
 473 }
 474
 475 /*
 476  * Lock torture reader kthread.  Repeatedly acquires and releases
 477  * the reader lock.
 478  */
 479 static int lock_torture_reader(void *arg)
 480 {
 481         struct lock_stress_stats *lrsp = arg;
 482         static DEFINE_TORTURE_RANDOM(rand);
 483
 484         VERBOSE_TOROUT_STRING("lock_torture_reader task started");
 485         set_user_nice(current, MAX_NICE);
 486
 487         do {
 488                 if ((torture_random(&rand) & 0xfffff) == 0)
 489                         schedule_timeout_uninterruptible(1);
 490
 491                 cxt.cur_ops->readlock();
 492                 lock_is_read_held = 1;
 493                 if (WARN_ON_ONCE(lock_is_write_held))
 494                         lrsp->n_lock_fail++; /* rare, but... */
 495
 496                 lrsp->n_lock_acquired++;
 497                 cxt.cur_ops->read_delay(&rand);
 498                 lock_is_read_held = 0;
 499                 cxt.cur_ops->readunlock();
 500
 501                 stutter_wait("lock_torture_reader");
 502         } while (!torture_must_stop());
 503         torture_kthread_stopping("lock_torture_reader");
 504         return 0;
 505 }
 506
 507 /*
 508  * Create an lock-torture-statistics message in the specified buffer.
 509  */
 510 static void __torture_print_stats(char *page,
 511                                   struct lock_stress_stats *statp, bool write)
 512 {
 513         bool fail = 0;
 514         int i, n_stress;
 515         long max = 0;
 516         long min = statp[0].n_lock_acquired;
 517         long long sum = 0;
 518
 519         n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress;
 520         for (i = 0; i < n_stress; i++) {
 521                 if (statp[i].n_lock_fail)
 522                         fail = true;
 523                 sum += statp[i].n_lock_acquired;
 524                 if (max < statp[i].n_lock_fail)
 525                         max = statp[i].n_lock_fail;
 526                 if (min > statp[i].n_lock_fail)
 527                         min = statp[i].n_lock_fail;
 528         }
 529         page += sprintf(page,
 530                         "%s:  Total: %lld  Max/Min: %ld/%ld %s  Fail: %d %s\n",
 531                         write ? "Writes" : "Reads ",
 532                         sum, max, min, max / 2 > min ? "???" : "",
 533                         fail, fail ? "!!!" : "");
 534         if (fail)
 535                 atomic_inc(&cxt.n_lock_torture_errors);
 536 }
 537
 538 /*
 539  * Print torture statistics.  Caller must ensure that there is only one
 540  * call to this function at a given time!!!  This is normally accomplished
 541  * by relying on the module system to only have one copy of the module
 542  * loaded, and then by giving the lock_torture_stats kthread full control
 543  * (or the init/cleanup functions when lock_torture_stats thread is not
 544  * running).
 545  */
 546 static void lock_torture_stats_print(void)
 547 {
 548         int size = cxt.nrealwriters_stress * 200 + 8192;
 549         char *buf;
 550
 551         if (cxt.cur_ops->readlock)
 552                 size += cxt.nrealreaders_stress * 200 + 8192;
 553
 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.lwsa, true);
 562         pr_alert("%s", buf);
 563         kfree(buf);
 564
 565         if (cxt.cur_ops->readlock) {
 566                 buf = kmalloc(size, GFP_KERNEL);
 567                 if (!buf) {
 568                         pr_err("lock_torture_stats_print: Out of memory, need: %d",
 569                                size);
 570                         return;
 571                 }
 572
 573                 __torture_print_stats(buf, cxt.lrsa, false);
 574                 pr_alert("%s", buf);
 575                 kfree(buf);
 576         }
 577 }
 578
 579 /*
 580  * Periodically prints torture statistics, if periodic statistics printing
 581  * was specified via the stat_interval module parameter.
 582  *
 583  * No need to worry about fullstop here, since this one doesn't reference
 584  * volatile state or register callbacks.
 585  */
 586 static int lock_torture_stats(void *arg)
 587 {
 588         VERBOSE_TOROUT_STRING("lock_torture_stats task started");
 589         do {
 590                 schedule_timeout_interruptible(stat_interval * HZ);
 591                 lock_torture_stats_print();
 592                 torture_shutdown_absorb("lock_torture_stats");
 593         } while (!torture_must_stop());
 594         torture_kthread_stopping("lock_torture_stats");
 595         return 0;
 596 }
 597
 598 static inline void
 599 lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
 600                                 const char *tag)
 601 {
 602         pr_alert("%s" TORTURE_FLAG
 603                  "--- %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",
 604                  torture_type, tag, cxt.debug_lock ? " [debug]": "",
 605                  cxt.nrealwriters_stress, cxt.nrealreaders_stress, stat_interval,
 606                  verbose, shuffle_interval, stutter, shutdown_secs,
 607                  onoff_interval, onoff_holdoff);
 608 }
 609
 610 static void lock_torture_cleanup(void)
 611 {
 612         int i;
 613
 614         if (torture_cleanup_begin())
 615                 return;
 616
 617         if (writer_tasks) {
 618                 for (i = 0; i < cxt.nrealwriters_stress; i++)
 619                         torture_stop_kthread(lock_torture_writer,
 620                                              writer_tasks[i]);
 621                 kfree(writer_tasks);
 622                 writer_tasks = NULL;
 623         }
 624
 625         if (reader_tasks) {
 626                 for (i = 0; i < cxt.nrealreaders_stress; i++)
 627                         torture_stop_kthread(lock_torture_reader,
 628                                              reader_tasks[i]);
 629                 kfree(reader_tasks);
 630                 reader_tasks = NULL;
 631         }
 632
 633         torture_stop_kthread(lock_torture_stats, stats_task);
 634         lock_torture_stats_print();  /* -After- the stats thread is stopped! */
 635
 636         if (atomic_read(&cxt.n_lock_torture_errors))
 637                 lock_torture_print_module_parms(cxt.cur_ops,
 638                                                 "End of test: FAILURE");
 639         else if (torture_onoff_failures())
 640                 lock_torture_print_module_parms(cxt.cur_ops,
 641                                                 "End of test: LOCK_HOTPLUG");
 642         else
 643                 lock_torture_print_module_parms(cxt.cur_ops,
 644                                                 "End of test: SUCCESS");
 645         torture_cleanup_end();
 646 }
 647
 648 static int __init lock_torture_init(void)
 649 {
 650         int i, j;
 651         int firsterr = 0;
 652         static struct lock_torture_ops *torture_ops[] = {
 653                 &lock_busted_ops,
 654                 &spin_lock_ops, &spin_lock_irq_ops,
 655                 &rw_lock_ops, &rw_lock_irq_ops,
 656                 &mutex_lock_ops,
 657                 &rwsem_lock_ops,
 658         };
 659
 660         if (!torture_init_begin(torture_type, verbose, &torture_runnable))
 661                 return -EBUSY;
 662
 663         /* Process args and tell the world that the torturer is on the job. */
 664         for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
 665                 cxt.cur_ops = torture_ops[i];
 666                 if (strcmp(torture_type, cxt.cur_ops->name) == 0)
 667                         break;
 668         }
 669         if (i == ARRAY_SIZE(torture_ops)) {
 670                 pr_alert("lock-torture: invalid torture type: \"%s\"\n",
 671                          torture_type);
 672                 pr_alert("lock-torture types:");
 673                 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
 674                         pr_alert(" %s", torture_ops[i]->name);
 675                 pr_alert("\n");
 676                 torture_init_end();
 677                 return -EINVAL;
 678         }
 679         if (cxt.cur_ops->init)
 680                 cxt.cur_ops->init(); /* no "goto unwind" prior to this point!!! */
 681
 682         if (nwriters_stress >= 0)
 683                 cxt.nrealwriters_stress = nwriters_stress;
 684         else
 685                 cxt.nrealwriters_stress = 2 * num_online_cpus();
 686
 687 #ifdef CONFIG_DEBUG_MUTEXES
 688         if (strncmp(torture_type, "mutex", 5) == 0)
 689                 cxt.debug_lock = true;
 690 #endif
 691 #ifdef CONFIG_DEBUG_SPINLOCK
 692         if ((strncmp(torture_type, "spin", 4) == 0) ||
 693             (strncmp(torture_type, "rw_lock", 7) == 0))
 694                 cxt.debug_lock = true;
 695 #endif
 696
 697         /* Initialize the statistics so that each run gets its own numbers. */
 698
 699         lock_is_write_held = 0;
 700         cxt.lwsa = kmalloc(sizeof(*cxt.lwsa) * cxt.nrealwriters_stress, GFP_KERNEL);
 701         if (cxt.lwsa == NULL) {
 702                 VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory");
 703                 firsterr = -ENOMEM;
 704                 goto unwind;
 705         }
 706         for (i = 0; i < cxt.nrealwriters_stress; i++) {
 707                 cxt.lwsa[i].n_lock_fail = 0;
 708                 cxt.lwsa[i].n_lock_acquired = 0;
 709         }
 710
 711         if (cxt.cur_ops->readlock) {
 712                 if (nreaders_stress >= 0)
 713                         cxt.nrealreaders_stress = nreaders_stress;
 714                 else {
 715                         /*
 716                          * By default distribute evenly the number of
 717                          * readers and writers. We still run the same number
 718                          * of threads as the writer-only locks default.
 719                          */
 720                         if (nwriters_stress < 0) /* user doesn't care */
 721                                 cxt.nrealwriters_stress = num_online_cpus();
 722                         cxt.nrealreaders_stress = cxt.nrealwriters_stress;
 723                 }
 724
 725                 lock_is_read_held = 0;
 726                 cxt.lrsa = kmalloc(sizeof(*cxt.lrsa) * cxt.nrealreaders_stress, GFP_KERNEL);
 727                 if (cxt.lrsa == NULL) {
 728                         VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory");
 729                         firsterr = -ENOMEM;
 730                         kfree(cxt.lwsa);
 731                         goto unwind;
 732                 }
 733
 734                 for (i = 0; i < cxt.nrealreaders_stress; i++) {
 735                         cxt.lrsa[i].n_lock_fail = 0;
 736                         cxt.lrsa[i].n_lock_acquired = 0;
 737                 }
 738         }
 739         lock_torture_print_module_parms(cxt.cur_ops, "Start of test");
 740
 741         /* Prepare torture context. */
 742         if (onoff_interval > 0) {
 743                 firsterr = torture_onoff_init(onoff_holdoff * HZ,
 744                                               onoff_interval * HZ);
 745                 if (firsterr)
 746                         goto unwind;
 747         }
 748         if (shuffle_interval > 0) {
 749                 firsterr = torture_shuffle_init(shuffle_interval);
 750                 if (firsterr)
 751                         goto unwind;
 752         }
 753         if (shutdown_secs > 0) {
 754                 firsterr = torture_shutdown_init(shutdown_secs,
 755                                                  lock_torture_cleanup);
 756                 if (firsterr)
 757                         goto unwind;
 758         }
 759         if (stutter > 0) {
 760                 firsterr = torture_stutter_init(stutter);
 761                 if (firsterr)
 762                         goto unwind;
 763         }
 764
 765         writer_tasks = kzalloc(cxt.nrealwriters_stress * sizeof(writer_tasks[0]),
 766                                GFP_KERNEL);
 767         if (writer_tasks == NULL) {
 768                 VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory");
 769                 firsterr = -ENOMEM;
 770                 goto unwind;
 771         }
 772
 773         if (cxt.cur_ops->readlock) {
 774                 reader_tasks = kzalloc(cxt.nrealreaders_stress * sizeof(reader_tasks[0]),
 775                                        GFP_KERNEL);
 776                 if (reader_tasks == NULL) {
 777                         VERBOSE_TOROUT_ERRSTRING("reader_tasks: Out of memory");
 778                         firsterr = -ENOMEM;
 779                         goto unwind;
 780                 }
 781         }
 782
 783         /*
 784          * Create the kthreads and start torturing (oh, those poor little locks).
 785          *
 786          * TODO: Note that we interleave writers with readers, giving writers a
 787          * slight advantage, by creating its kthread first. This can be modified
 788          * for very specific needs, or even let the user choose the policy, if
 789          * ever wanted.
 790          */
 791         for (i = 0, j = 0; i < cxt.nrealwriters_stress ||
 792                     j < cxt.nrealreaders_stress; i++, j++) {
 793                 if (i >= cxt.nrealwriters_stress)
 794                         goto create_reader;
 795
 796                 /* Create writer. */
 797                 firsterr = torture_create_kthread(lock_torture_writer, &cxt.lwsa[i],
 798                                                   writer_tasks[i]);
 799                 if (firsterr)
 800                         goto unwind;
 801
 802         create_reader:
 803                 if (cxt.cur_ops->readlock == NULL || (j >= cxt.nrealreaders_stress))
 804                         continue;
 805                 /* Create reader. */
 806                 firsterr = torture_create_kthread(lock_torture_reader, &cxt.lrsa[j],
 807                                                   reader_tasks[j]);
 808                 if (firsterr)
 809                         goto unwind;
 810         }
 811         if (stat_interval > 0) {
 812                 firsterr = torture_create_kthread(lock_torture_stats, NULL,
 813                                                   stats_task);
 814                 if (firsterr)
 815                         goto unwind;
 816         }
 817         torture_init_end();
 818         return 0;
 819
 820 unwind:
 821         torture_init_end();
 822         lock_torture_cleanup();
 823         return firsterr;
 824 }
 825
 826 module_init(lock_torture_init);
 827 module_exit(lock_torture_cleanup);