kernel/locking/locktorture.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Module-based torture test facility for locking
   4  *
   5  * Copyright (C) IBM Corporation, 2014
   6  *
   7  * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
   8  *          Davidlohr Bueso <dave@stgolabs.net>
   9  *      Based on kernel/rcu/torture.c.
  10  */
  11
  12 #define pr_fmt(fmt) fmt
  13
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/kthread.h>
  17 #include <linux/sched/rt.h>
  18 #include <linux/spinlock.h>
  19 #include <linux/mutex.h>
  20 #include <linux/rwsem.h>
  21 #include <linux/smp.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/sched.h>
  24 #include <uapi/linux/sched/types.h>
  25 #include <linux/rtmutex.h>
  26 #include <linux/atomic.h>
  27 #include <linux/moduleparam.h>
  28 #include <linux/delay.h>
  29 #include <linux/slab.h>
  30 #include <linux/torture.h>
  31 #include <linux/reboot.h>
  32
  33 MODULE_LICENSE("GPL");
  34 MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>");
  35
  36 torture_param(int, acq_writer_lim, 0, "Write_acquisition time limit (jiffies).");
  37 torture_param(int, call_rcu_chains, 0, "Self-propagate call_rcu() chains during test (0=disable).");
  38 torture_param(int, long_hold, 100, "Do occasional long hold of lock (ms), 0=disable");
  39 torture_param(int, nested_locks, 0, "Number of nested locks (max = 8)");
  40 torture_param(int, nreaders_stress, -1, "Number of read-locking stress-test threads");
  41 torture_param(int, nwriters_stress, -1, "Number of write-locking stress-test threads");
  42 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
  43 torture_param(int, onoff_interval, 0, "Time between CPU hotplugs (s), 0=disable");
  44 torture_param(int, rt_boost, 2,
  45                    "Do periodic rt-boost. 0=Disable, 1=Only for rt_mutex, 2=For all lock types.");
  46 torture_param(int, rt_boost_factor, 50, "A factor determining how often rt-boost happens.");
  47 torture_param(int, shuffle_interval, 3, "Number of jiffies between shuffles, 0=disable");
  48 torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable.");
  49 torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s");
  50 torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
  51 torture_param(int, verbose, 1, "Enable verbose debugging printk()s");
  52 torture_param(int, writer_fifo, 0, "Run writers at sched_set_fifo() priority");
  53 /* Going much higher trips "BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!" errors */
  54 #define MAX_NESTED_LOCKS 8
  55
  56 static char *torture_type = IS_ENABLED(CONFIG_PREEMPT_RT) ? "raw_spin_lock" : "spin_lock";
  57 module_param(torture_type, charp, 0444);
  58 MODULE_PARM_DESC(torture_type,
  59                  "Type of lock to torture (spin_lock, spin_lock_irq, mutex_lock, ...)");
  60
  61 static cpumask_var_t bind_readers; // Bind the readers to the specified set of CPUs.
  62 static cpumask_var_t bind_writers; // Bind the writers to the specified set of CPUs.
  63
  64 // Parse a cpumask kernel parameter.  If there are more users later on,
  65 // this might need to got to a more central location.
  66 static int param_set_cpumask(const char *val, const struct kernel_param *kp)
  67 {
  68         cpumask_var_t *cm_bind = kp->arg;
  69         int ret;
  70         char *s;
  71
  72         if (!alloc_cpumask_var(cm_bind, GFP_KERNEL)) {
  73                 s = "Out of memory";
  74                 ret = -ENOMEM;
  75                 goto out_err;
  76         }
  77         ret = cpulist_parse(val, *cm_bind);
  78         if (!ret)
  79                 return ret;
  80         s = "Bad CPU range";
  81 out_err:
  82         pr_warn("%s: %s, all CPUs set\n", kp->name, s);
  83         cpumask_setall(*cm_bind);
  84         return ret;
  85 }
  86
  87 // Output a cpumask kernel parameter.
  88 static int param_get_cpumask(char *buffer, const struct kernel_param *kp)
  89 {
  90         cpumask_var_t *cm_bind = kp->arg;
  91
  92         return sprintf(buffer, "%*pbl", cpumask_pr_args(*cm_bind));
  93 }
  94
  95 static bool cpumask_nonempty(cpumask_var_t mask)
  96 {
  97         return cpumask_available(mask) && !cpumask_empty(mask);
  98 }
  99
 100 static const struct kernel_param_ops lt_bind_ops = {
 101         .set = param_set_cpumask,
 102         .get = param_get_cpumask,
 103 };
 104
 105 module_param_cb(bind_readers, &lt_bind_ops, &bind_readers, 0644);
 106 module_param_cb(bind_writers, &lt_bind_ops, &bind_writers, 0644);
 107
 108 long torture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask);
 109
 110 static struct task_struct *stats_task;
 111 static struct task_struct **writer_tasks;
 112 static struct task_struct **reader_tasks;
 113
 114 static bool lock_is_write_held;
 115 static atomic_t lock_is_read_held;
 116 static unsigned long last_lock_release;
 117
 118 struct lock_stress_stats {
 119         long n_lock_fail;
 120         long n_lock_acquired;
 121 };
 122
 123 struct call_rcu_chain {
 124         struct rcu_head crc_rh;
 125         bool crc_stop;
 126 };
 127 struct call_rcu_chain *call_rcu_chain_list;
 128
 129 /* Forward reference. */
 130 static void lock_torture_cleanup(void);
 131
 132 /*
 133  * Operations vector for selecting different types of tests.
 134  */
 135 struct lock_torture_ops {
 136         void (*init)(void);
 137         void (*exit)(void);
 138         int (*nested_lock)(int tid, u32 lockset);
 139         int (*writelock)(int tid);
 140         void (*write_delay)(struct torture_random_state *trsp);
 141         void (*task_boost)(struct torture_random_state *trsp);
 142         void (*writeunlock)(int tid);
 143         void (*nested_unlock)(int tid, u32 lockset);
 144         int (*readlock)(int tid);
 145         void (*read_delay)(struct torture_random_state *trsp);
 146         void (*readunlock)(int tid);
 147
 148         unsigned long flags; /* for irq spinlocks */
 149         const char *name;
 150 };
 151
 152 struct lock_torture_cxt {
 153         int nrealwriters_stress;
 154         int nrealreaders_stress;
 155         bool debug_lock;
 156         bool init_called;
 157         atomic_t n_lock_torture_errors;
 158         struct lock_torture_ops *cur_ops;
 159         struct lock_stress_stats *lwsa; /* writer statistics */
 160         struct lock_stress_stats *lrsa; /* reader statistics */
 161 };
 162 static struct lock_torture_cxt cxt = { 0, 0, false, false,
 163                                        ATOMIC_INIT(0),
 164                                        NULL, NULL};
 165 /*
 166  * Definitions for lock torture testing.
 167  */
 168
 169 static int torture_lock_busted_write_lock(int tid __maybe_unused)
 170 {
 171         return 0;  /* BUGGY, do not use in real life!!! */
 172 }
 173
 174 static void torture_lock_busted_write_delay(struct torture_random_state *trsp)
 175 {
 176         /* We want a long delay occasionally to force massive contention.  */
 177         if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold)))
 178                 mdelay(long_hold);
 179         if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
 180                 torture_preempt_schedule();  /* Allow test to be preempted. */
 181 }
 182
 183 static void torture_lock_busted_write_unlock(int tid __maybe_unused)
 184 {
 185           /* BUGGY, do not use in real life!!! */
 186 }
 187
 188 static void __torture_rt_boost(struct torture_random_state *trsp)
 189 {
 190         const unsigned int factor = rt_boost_factor;
 191
 192         if (!rt_task(current)) {
 193                 /*
 194                  * Boost priority once every rt_boost_factor operations. When
 195                  * the task tries to take the lock, the rtmutex it will account
 196                  * for the new priority, and do any corresponding pi-dance.
 197                  */
 198                 if (trsp && !(torture_random(trsp) %
 199                               (cxt.nrealwriters_stress * factor))) {
 200                         sched_set_fifo(current);
 201                 } else /* common case, do nothing */
 202                         return;
 203         } else {
 204                 /*
 205                  * The task will remain boosted for another 10 * rt_boost_factor
 206                  * operations, then restored back to its original prio, and so
 207                  * forth.
 208                  *
 209                  * When @trsp is nil, we want to force-reset the task for
 210                  * stopping the kthread.
 211                  */
 212                 if (!trsp || !(torture_random(trsp) %
 213                                (cxt.nrealwriters_stress * factor * 2))) {
 214                         sched_set_normal(current, 0);
 215                 } else /* common case, do nothing */
 216                         return;
 217         }
 218 }
 219
 220 static void torture_rt_boost(struct torture_random_state *trsp)
 221 {
 222         if (rt_boost != 2)
 223                 return;
 224
 225         __torture_rt_boost(trsp);
 226 }
 227
 228 static struct lock_torture_ops lock_busted_ops = {
 229         .writelock      = torture_lock_busted_write_lock,
 230         .write_delay    = torture_lock_busted_write_delay,
 231         .task_boost     = torture_rt_boost,
 232         .writeunlock    = torture_lock_busted_write_unlock,
 233         .readlock       = NULL,
 234         .read_delay     = NULL,
 235         .readunlock     = NULL,
 236         .name           = "lock_busted"
 237 };
 238
 239 static DEFINE_SPINLOCK(torture_spinlock);
 240
 241 static int torture_spin_lock_write_lock(int tid __maybe_unused)
 242 __acquires(torture_spinlock)
 243 {
 244         spin_lock(&torture_spinlock);
 245         return 0;
 246 }
 247
 248 static void torture_spin_lock_write_delay(struct torture_random_state *trsp)
 249 {
 250         const unsigned long shortdelay_us = 2;
 251         unsigned long j;
 252
 253         /* We want a short delay mostly to emulate likely code, and
 254          * we want a long delay occasionally to force massive contention.
 255          */
 256         if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold))) {
 257                 j = jiffies;
 258                 mdelay(long_hold);
 259                 pr_alert("%s: delay = %lu jiffies.\n", __func__, jiffies - j);
 260         }
 261         if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 200 * shortdelay_us)))
 262                 udelay(shortdelay_us);
 263         if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
 264                 torture_preempt_schedule();  /* Allow test to be preempted. */
 265 }
 266
 267 static void torture_spin_lock_write_unlock(int tid __maybe_unused)
 268 __releases(torture_spinlock)
 269 {
 270         spin_unlock(&torture_spinlock);
 271 }
 272
 273 static struct lock_torture_ops spin_lock_ops = {
 274         .writelock      = torture_spin_lock_write_lock,
 275         .write_delay    = torture_spin_lock_write_delay,
 276         .task_boost     = torture_rt_boost,
 277         .writeunlock    = torture_spin_lock_write_unlock,
 278         .readlock       = NULL,
 279         .read_delay     = NULL,
 280         .readunlock     = NULL,
 281         .name           = "spin_lock"
 282 };
 283
 284 static int torture_spin_lock_write_lock_irq(int tid __maybe_unused)
 285 __acquires(torture_spinlock)
 286 {
 287         unsigned long flags;
 288
 289         spin_lock_irqsave(&torture_spinlock, flags);
 290         cxt.cur_ops->flags = flags;
 291         return 0;
 292 }
 293
 294 static void torture_lock_spin_write_unlock_irq(int tid __maybe_unused)
 295 __releases(torture_spinlock)
 296 {
 297         spin_unlock_irqrestore(&torture_spinlock, cxt.cur_ops->flags);
 298 }
 299
 300 static struct lock_torture_ops spin_lock_irq_ops = {
 301         .writelock      = torture_spin_lock_write_lock_irq,
 302         .write_delay    = torture_spin_lock_write_delay,
 303         .task_boost     = torture_rt_boost,
 304         .writeunlock    = torture_lock_spin_write_unlock_irq,
 305         .readlock       = NULL,
 306         .read_delay     = NULL,
 307         .readunlock     = NULL,
 308         .name           = "spin_lock_irq"
 309 };
 310
 311 static DEFINE_RAW_SPINLOCK(torture_raw_spinlock);
 312
 313 static int torture_raw_spin_lock_write_lock(int tid __maybe_unused)
 314 __acquires(torture_raw_spinlock)
 315 {
 316         raw_spin_lock(&torture_raw_spinlock);
 317         return 0;
 318 }
 319
 320 static void torture_raw_spin_lock_write_unlock(int tid __maybe_unused)
 321 __releases(torture_raw_spinlock)
 322 {
 323         raw_spin_unlock(&torture_raw_spinlock);
 324 }
 325
 326 static struct lock_torture_ops raw_spin_lock_ops = {
 327         .writelock      = torture_raw_spin_lock_write_lock,
 328         .write_delay    = torture_spin_lock_write_delay,
 329         .task_boost     = torture_rt_boost,
 330         .writeunlock    = torture_raw_spin_lock_write_unlock,
 331         .readlock       = NULL,
 332         .read_delay     = NULL,
 333         .readunlock     = NULL,
 334         .name           = "raw_spin_lock"
 335 };
 336
 337 static int torture_raw_spin_lock_write_lock_irq(int tid __maybe_unused)
 338 __acquires(torture_raw_spinlock)
 339 {
 340         unsigned long flags;
 341
 342         raw_spin_lock_irqsave(&torture_raw_spinlock, flags);
 343         cxt.cur_ops->flags = flags;
 344         return 0;
 345 }
 346
 347 static void torture_raw_spin_lock_write_unlock_irq(int tid __maybe_unused)
 348 __releases(torture_raw_spinlock)
 349 {
 350         raw_spin_unlock_irqrestore(&torture_raw_spinlock, cxt.cur_ops->flags);
 351 }
 352
 353 static struct lock_torture_ops raw_spin_lock_irq_ops = {
 354         .writelock      = torture_raw_spin_lock_write_lock_irq,
 355         .write_delay    = torture_spin_lock_write_delay,
 356         .task_boost     = torture_rt_boost,
 357         .writeunlock    = torture_raw_spin_lock_write_unlock_irq,
 358         .readlock       = NULL,
 359         .read_delay     = NULL,
 360         .readunlock     = NULL,
 361         .name           = "raw_spin_lock_irq"
 362 };
 363
 364 static DEFINE_RWLOCK(torture_rwlock);
 365
 366 static int torture_rwlock_write_lock(int tid __maybe_unused)
 367 __acquires(torture_rwlock)
 368 {
 369         write_lock(&torture_rwlock);
 370         return 0;
 371 }
 372
 373 static void torture_rwlock_write_delay(struct torture_random_state *trsp)
 374 {
 375         const unsigned long shortdelay_us = 2;
 376
 377         /* We want a short delay mostly to emulate likely code, and
 378          * we want a long delay occasionally to force massive contention.
 379          */
 380         if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold)))
 381                 mdelay(long_hold);
 382         else
 383                 udelay(shortdelay_us);
 384 }
 385
 386 static void torture_rwlock_write_unlock(int tid __maybe_unused)
 387 __releases(torture_rwlock)
 388 {
 389         write_unlock(&torture_rwlock);
 390 }
 391
 392 static int torture_rwlock_read_lock(int tid __maybe_unused)
 393 __acquires(torture_rwlock)
 394 {
 395         read_lock(&torture_rwlock);
 396         return 0;
 397 }
 398
 399 static void torture_rwlock_read_delay(struct torture_random_state *trsp)
 400 {
 401         const unsigned long shortdelay_us = 10;
 402
 403         /* We want a short delay mostly to emulate likely code, and
 404          * we want a long delay occasionally to force massive contention.
 405          */
 406         if (long_hold && !(torture_random(trsp) % (cxt.nrealreaders_stress * 2000 * long_hold)))
 407                 mdelay(long_hold);
 408         else
 409                 udelay(shortdelay_us);
 410 }
 411
 412 static void torture_rwlock_read_unlock(int tid __maybe_unused)
 413 __releases(torture_rwlock)
 414 {
 415         read_unlock(&torture_rwlock);
 416 }
 417
 418 static struct lock_torture_ops rw_lock_ops = {
 419         .writelock      = torture_rwlock_write_lock,
 420         .write_delay    = torture_rwlock_write_delay,
 421         .task_boost     = torture_rt_boost,
 422         .writeunlock    = torture_rwlock_write_unlock,
 423         .readlock       = torture_rwlock_read_lock,
 424         .read_delay     = torture_rwlock_read_delay,
 425         .readunlock     = torture_rwlock_read_unlock,
 426         .name           = "rw_lock"
 427 };
 428
 429 static int torture_rwlock_write_lock_irq(int tid __maybe_unused)
 430 __acquires(torture_rwlock)
 431 {
 432         unsigned long flags;
 433
 434         write_lock_irqsave(&torture_rwlock, flags);
 435         cxt.cur_ops->flags = flags;
 436         return 0;
 437 }
 438
 439 static void torture_rwlock_write_unlock_irq(int tid __maybe_unused)
 440 __releases(torture_rwlock)
 441 {
 442         write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
 443 }
 444
 445 static int torture_rwlock_read_lock_irq(int tid __maybe_unused)
 446 __acquires(torture_rwlock)
 447 {
 448         unsigned long flags;
 449
 450         read_lock_irqsave(&torture_rwlock, flags);
 451         cxt.cur_ops->flags = flags;
 452         return 0;
 453 }
 454
 455 static void torture_rwlock_read_unlock_irq(int tid __maybe_unused)
 456 __releases(torture_rwlock)
 457 {
 458         read_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
 459 }
 460
 461 static struct lock_torture_ops rw_lock_irq_ops = {
 462         .writelock      = torture_rwlock_write_lock_irq,
 463         .write_delay    = torture_rwlock_write_delay,
 464         .task_boost     = torture_rt_boost,
 465         .writeunlock    = torture_rwlock_write_unlock_irq,
 466         .readlock       = torture_rwlock_read_lock_irq,
 467         .read_delay     = torture_rwlock_read_delay,
 468         .readunlock     = torture_rwlock_read_unlock_irq,
 469         .name           = "rw_lock_irq"
 470 };
 471
 472 static DEFINE_MUTEX(torture_mutex);
 473 static struct mutex torture_nested_mutexes[MAX_NESTED_LOCKS];
 474 static struct lock_class_key nested_mutex_keys[MAX_NESTED_LOCKS];
 475
 476 static void torture_mutex_init(void)
 477 {
 478         int i;
 479
 480         for (i = 0; i < MAX_NESTED_LOCKS; i++)
 481                 __mutex_init(&torture_nested_mutexes[i], __func__,
 482                              &nested_mutex_keys[i]);
 483 }
 484
 485 static int torture_mutex_nested_lock(int tid __maybe_unused,
 486                                      u32 lockset)
 487 {
 488         int i;
 489
 490         for (i = 0; i < nested_locks; i++)
 491                 if (lockset & (1 << i))
 492                         mutex_lock(&torture_nested_mutexes[i]);
 493         return 0;
 494 }
 495
 496 static int torture_mutex_lock(int tid __maybe_unused)
 497 __acquires(torture_mutex)
 498 {
 499         mutex_lock(&torture_mutex);
 500         return 0;
 501 }
 502
 503 static void torture_mutex_delay(struct torture_random_state *trsp)
 504 {
 505         /* We want a long delay occasionally to force massive contention.  */
 506         if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold)))
 507                 mdelay(long_hold * 5);
 508         if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
 509                 torture_preempt_schedule();  /* Allow test to be preempted. */
 510 }
 511
 512 static void torture_mutex_unlock(int tid __maybe_unused)
 513 __releases(torture_mutex)
 514 {
 515         mutex_unlock(&torture_mutex);
 516 }
 517
 518 static void torture_mutex_nested_unlock(int tid __maybe_unused,
 519                                         u32 lockset)
 520 {
 521         int i;
 522
 523         for (i = nested_locks - 1; i >= 0; i--)
 524                 if (lockset & (1 << i))
 525                         mutex_unlock(&torture_nested_mutexes[i]);
 526 }
 527
 528 static struct lock_torture_ops mutex_lock_ops = {
 529         .init           = torture_mutex_init,
 530         .nested_lock    = torture_mutex_nested_lock,
 531         .writelock      = torture_mutex_lock,
 532         .write_delay    = torture_mutex_delay,
 533         .task_boost     = torture_rt_boost,
 534         .writeunlock    = torture_mutex_unlock,
 535         .nested_unlock  = torture_mutex_nested_unlock,
 536         .readlock       = NULL,
 537         .read_delay     = NULL,
 538         .readunlock     = NULL,
 539         .name           = "mutex_lock"
 540 };
 541
 542 #include <linux/ww_mutex.h>
 543 /*
 544  * The torture ww_mutexes should belong to the same lock class as
 545  * torture_ww_class to avoid lockdep problem. The ww_mutex_init()
 546  * function is called for initialization to ensure that.
 547  */
 548 static DEFINE_WD_CLASS(torture_ww_class);
 549 static struct ww_mutex torture_ww_mutex_0, torture_ww_mutex_1, torture_ww_mutex_2;
 550 static struct ww_acquire_ctx *ww_acquire_ctxs;
 551
 552 static void torture_ww_mutex_init(void)
 553 {
 554         ww_mutex_init(&torture_ww_mutex_0, &torture_ww_class);
 555         ww_mutex_init(&torture_ww_mutex_1, &torture_ww_class);
 556         ww_mutex_init(&torture_ww_mutex_2, &torture_ww_class);
 557
 558         ww_acquire_ctxs = kmalloc_array(cxt.nrealwriters_stress,
 559                                         sizeof(*ww_acquire_ctxs),
 560                                         GFP_KERNEL);
 561         if (!ww_acquire_ctxs)
 562                 VERBOSE_TOROUT_STRING("ww_acquire_ctx: Out of memory");
 563 }
 564
 565 static void torture_ww_mutex_exit(void)
 566 {
 567         kfree(ww_acquire_ctxs);
 568 }
 569
 570 static int torture_ww_mutex_lock(int tid)
 571 __acquires(torture_ww_mutex_0)
 572 __acquires(torture_ww_mutex_1)
 573 __acquires(torture_ww_mutex_2)
 574 {
 575         LIST_HEAD(list);
 576         struct reorder_lock {
 577                 struct list_head link;
 578                 struct ww_mutex *lock;
 579         } locks[3], *ll, *ln;
 580         struct ww_acquire_ctx *ctx = &ww_acquire_ctxs[tid];
 581
 582         locks[0].lock = &torture_ww_mutex_0;
 583         list_add(&locks[0].link, &list);
 584
 585         locks[1].lock = &torture_ww_mutex_1;
 586         list_add(&locks[1].link, &list);
 587
 588         locks[2].lock = &torture_ww_mutex_2;
 589         list_add(&locks[2].link, &list);
 590
 591         ww_acquire_init(ctx, &torture_ww_class);
 592
 593         list_for_each_entry(ll, &list, link) {
 594                 int err;
 595
 596                 err = ww_mutex_lock(ll->lock, ctx);
 597                 if (!err)
 598                         continue;
 599
 600                 ln = ll;
 601                 list_for_each_entry_continue_reverse(ln, &list, link)
 602                         ww_mutex_unlock(ln->lock);
 603
 604                 if (err != -EDEADLK)
 605                         return err;
 606
 607                 ww_mutex_lock_slow(ll->lock, ctx);
 608                 list_move(&ll->link, &list);
 609         }
 610
 611         return 0;
 612 }
 613
 614 static void torture_ww_mutex_unlock(int tid)
 615 __releases(torture_ww_mutex_0)
 616 __releases(torture_ww_mutex_1)
 617 __releases(torture_ww_mutex_2)
 618 {
 619         struct ww_acquire_ctx *ctx = &ww_acquire_ctxs[tid];
 620
 621         ww_mutex_unlock(&torture_ww_mutex_0);
 622         ww_mutex_unlock(&torture_ww_mutex_1);
 623         ww_mutex_unlock(&torture_ww_mutex_2);
 624         ww_acquire_fini(ctx);
 625 }
 626
 627 static struct lock_torture_ops ww_mutex_lock_ops = {
 628         .init           = torture_ww_mutex_init,
 629         .exit           = torture_ww_mutex_exit,
 630         .writelock      = torture_ww_mutex_lock,
 631         .write_delay    = torture_mutex_delay,
 632         .task_boost     = torture_rt_boost,
 633         .writeunlock    = torture_ww_mutex_unlock,
 634         .readlock       = NULL,
 635         .read_delay     = NULL,
 636         .readunlock     = NULL,
 637         .name           = "ww_mutex_lock"
 638 };
 639
 640 #ifdef CONFIG_RT_MUTEXES
 641 static DEFINE_RT_MUTEX(torture_rtmutex);
 642 static struct rt_mutex torture_nested_rtmutexes[MAX_NESTED_LOCKS];
 643 static struct lock_class_key nested_rtmutex_keys[MAX_NESTED_LOCKS];
 644
 645 static void torture_rtmutex_init(void)
 646 {
 647         int i;
 648
 649         for (i = 0; i < MAX_NESTED_LOCKS; i++)
 650                 __rt_mutex_init(&torture_nested_rtmutexes[i], __func__,
 651                                 &nested_rtmutex_keys[i]);
 652 }
 653
 654 static int torture_rtmutex_nested_lock(int tid __maybe_unused,
 655                                        u32 lockset)
 656 {
 657         int i;
 658
 659         for (i = 0; i < nested_locks; i++)
 660                 if (lockset & (1 << i))
 661                         rt_mutex_lock(&torture_nested_rtmutexes[i]);
 662         return 0;
 663 }
 664
 665 static int torture_rtmutex_lock(int tid __maybe_unused)
 666 __acquires(torture_rtmutex)
 667 {
 668         rt_mutex_lock(&torture_rtmutex);
 669         return 0;
 670 }
 671
 672 static void torture_rtmutex_delay(struct torture_random_state *trsp)
 673 {
 674         const unsigned long shortdelay_us = 2;
 675
 676         /*
 677          * We want a short delay mostly to emulate likely code, and
 678          * we want a long delay occasionally to force massive contention.
 679          */
 680         if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold)))
 681                 mdelay(long_hold);
 682         if (!(torture_random(trsp) %
 683               (cxt.nrealwriters_stress * 200 * shortdelay_us)))
 684                 udelay(shortdelay_us);
 685         if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
 686                 torture_preempt_schedule();  /* Allow test to be preempted. */
 687 }
 688
 689 static void torture_rtmutex_unlock(int tid __maybe_unused)
 690 __releases(torture_rtmutex)
 691 {
 692         rt_mutex_unlock(&torture_rtmutex);
 693 }
 694
 695 static void torture_rt_boost_rtmutex(struct torture_random_state *trsp)
 696 {
 697         if (!rt_boost)
 698                 return;
 699
 700         __torture_rt_boost(trsp);
 701 }
 702
 703 static void torture_rtmutex_nested_unlock(int tid __maybe_unused,
 704                                           u32 lockset)
 705 {
 706         int i;
 707
 708         for (i = nested_locks - 1; i >= 0; i--)
 709                 if (lockset & (1 << i))
 710                         rt_mutex_unlock(&torture_nested_rtmutexes[i]);
 711 }
 712
 713 static struct lock_torture_ops rtmutex_lock_ops = {
 714         .init           = torture_rtmutex_init,
 715         .nested_lock    = torture_rtmutex_nested_lock,
 716         .writelock      = torture_rtmutex_lock,
 717         .write_delay    = torture_rtmutex_delay,
 718         .task_boost     = torture_rt_boost_rtmutex,
 719         .writeunlock    = torture_rtmutex_unlock,
 720         .nested_unlock  = torture_rtmutex_nested_unlock,
 721         .readlock       = NULL,
 722         .read_delay     = NULL,
 723         .readunlock     = NULL,
 724         .name           = "rtmutex_lock"
 725 };
 726 #endif
 727
 728 static DECLARE_RWSEM(torture_rwsem);
 729 static int torture_rwsem_down_write(int tid __maybe_unused)
 730 __acquires(torture_rwsem)
 731 {
 732         down_write(&torture_rwsem);
 733         return 0;
 734 }
 735
 736 static void torture_rwsem_write_delay(struct torture_random_state *trsp)
 737 {
 738         /* We want a long delay occasionally to force massive contention.  */
 739         if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold)))
 740                 mdelay(long_hold * 10);
 741         if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
 742                 torture_preempt_schedule();  /* Allow test to be preempted. */
 743 }
 744
 745 static void torture_rwsem_up_write(int tid __maybe_unused)
 746 __releases(torture_rwsem)
 747 {
 748         up_write(&torture_rwsem);
 749 }
 750
 751 static int torture_rwsem_down_read(int tid __maybe_unused)
 752 __acquires(torture_rwsem)
 753 {
 754         down_read(&torture_rwsem);
 755         return 0;
 756 }
 757
 758 static void torture_rwsem_read_delay(struct torture_random_state *trsp)
 759 {
 760         /* We want a long delay occasionally to force massive contention.  */
 761         if (long_hold && !(torture_random(trsp) % (cxt.nrealreaders_stress * 2000 * long_hold)))
 762                 mdelay(long_hold * 2);
 763         else
 764                 mdelay(long_hold / 2);
 765         if (!(torture_random(trsp) % (cxt.nrealreaders_stress * 20000)))
 766                 torture_preempt_schedule();  /* Allow test to be preempted. */
 767 }
 768
 769 static void torture_rwsem_up_read(int tid __maybe_unused)
 770 __releases(torture_rwsem)
 771 {
 772         up_read(&torture_rwsem);
 773 }
 774
 775 static struct lock_torture_ops rwsem_lock_ops = {
 776         .writelock      = torture_rwsem_down_write,
 777         .write_delay    = torture_rwsem_write_delay,
 778         .task_boost     = torture_rt_boost,
 779         .writeunlock    = torture_rwsem_up_write,
 780         .readlock       = torture_rwsem_down_read,
 781         .read_delay     = torture_rwsem_read_delay,
 782         .readunlock     = torture_rwsem_up_read,
 783         .name           = "rwsem_lock"
 784 };
 785
 786 #include <linux/percpu-rwsem.h>
 787 static struct percpu_rw_semaphore pcpu_rwsem;
 788
 789 static void torture_percpu_rwsem_init(void)
 790 {
 791         BUG_ON(percpu_init_rwsem(&pcpu_rwsem));
 792 }
 793
 794 static void torture_percpu_rwsem_exit(void)
 795 {
 796         percpu_free_rwsem(&pcpu_rwsem);
 797 }
 798
 799 static int torture_percpu_rwsem_down_write(int tid __maybe_unused)
 800 __acquires(pcpu_rwsem)
 801 {
 802         percpu_down_write(&pcpu_rwsem);
 803         return 0;
 804 }
 805
 806 static void torture_percpu_rwsem_up_write(int tid __maybe_unused)
 807 __releases(pcpu_rwsem)
 808 {
 809         percpu_up_write(&pcpu_rwsem);
 810 }
 811
 812 static int torture_percpu_rwsem_down_read(int tid __maybe_unused)
 813 __acquires(pcpu_rwsem)
 814 {
 815         percpu_down_read(&pcpu_rwsem);
 816         return 0;
 817 }
 818
 819 static void torture_percpu_rwsem_up_read(int tid __maybe_unused)
 820 __releases(pcpu_rwsem)
 821 {
 822         percpu_up_read(&pcpu_rwsem);
 823 }
 824
 825 static struct lock_torture_ops percpu_rwsem_lock_ops = {
 826         .init           = torture_percpu_rwsem_init,
 827         .exit           = torture_percpu_rwsem_exit,
 828         .writelock      = torture_percpu_rwsem_down_write,
 829         .write_delay    = torture_rwsem_write_delay,
 830         .task_boost     = torture_rt_boost,
 831         .writeunlock    = torture_percpu_rwsem_up_write,
 832         .readlock       = torture_percpu_rwsem_down_read,
 833         .read_delay     = torture_rwsem_read_delay,
 834         .readunlock     = torture_percpu_rwsem_up_read,
 835         .name           = "percpu_rwsem_lock"
 836 };
 837
 838 /*
 839  * Lock torture writer kthread.  Repeatedly acquires and releases
 840  * the lock, checking for duplicate acquisitions.
 841  */
 842 static int lock_torture_writer(void *arg)
 843 {
 844         unsigned long j;
 845         unsigned long j1;
 846         u32 lockset_mask;
 847         struct lock_stress_stats *lwsp = arg;
 848         DEFINE_TORTURE_RANDOM(rand);
 849         bool skip_main_lock;
 850         int tid = lwsp - cxt.lwsa;
 851
 852         VERBOSE_TOROUT_STRING("lock_torture_writer task started");
 853         if (!rt_task(current))
 854                 set_user_nice(current, MAX_NICE);
 855
 856         do {
 857                 if ((torture_random(&rand) & 0xfffff) == 0)
 858                         schedule_timeout_uninterruptible(1);
 859
 860                 lockset_mask = torture_random(&rand);
 861                 /*
 862                  * When using nested_locks, we want to occasionally
 863                  * skip the main lock so we can avoid always serializing
 864                  * the lock chains on that central lock. By skipping the
 865                  * main lock occasionally, we can create different
 866                  * contention patterns (allowing for multiple disjoint
 867                  * blocked trees)
 868                  */
 869                 skip_main_lock = (nested_locks &&
 870                                  !(torture_random(&rand) % 100));
 871
 872                 cxt.cur_ops->task_boost(&rand);
 873                 if (cxt.cur_ops->nested_lock)
 874                         cxt.cur_ops->nested_lock(tid, lockset_mask);
 875
 876                 if (!skip_main_lock) {
 877                         if (acq_writer_lim > 0)
 878                                 j = jiffies;
 879                         cxt.cur_ops->writelock(tid);
 880                         if (WARN_ON_ONCE(lock_is_write_held))
 881                                 lwsp->n_lock_fail++;
 882                         lock_is_write_held = true;
 883                         if (WARN_ON_ONCE(atomic_read(&lock_is_read_held)))
 884                                 lwsp->n_lock_fail++; /* rare, but... */
 885                         if (acq_writer_lim > 0) {
 886                                 j1 = jiffies;
 887                                 WARN_ONCE(time_after(j1, j + acq_writer_lim),
 888                                           "%s: Lock acquisition took %lu jiffies.\n",
 889                                           __func__, j1 - j);
 890                         }
 891                         lwsp->n_lock_acquired++;
 892
 893                         cxt.cur_ops->write_delay(&rand);
 894
 895                         lock_is_write_held = false;
 896                         WRITE_ONCE(last_lock_release, jiffies);
 897                         cxt.cur_ops->writeunlock(tid);
 898                 }
 899                 if (cxt.cur_ops->nested_unlock)
 900                         cxt.cur_ops->nested_unlock(tid, lockset_mask);
 901
 902                 stutter_wait("lock_torture_writer");
 903         } while (!torture_must_stop());
 904
 905         cxt.cur_ops->task_boost(NULL); /* reset prio */
 906         torture_kthread_stopping("lock_torture_writer");
 907         return 0;
 908 }
 909
 910 /*
 911  * Lock torture reader kthread.  Repeatedly acquires and releases
 912  * the reader lock.
 913  */
 914 static int lock_torture_reader(void *arg)
 915 {
 916         struct lock_stress_stats *lrsp = arg;
 917         int tid = lrsp - cxt.lrsa;
 918         DEFINE_TORTURE_RANDOM(rand);
 919
 920         VERBOSE_TOROUT_STRING("lock_torture_reader task started");
 921         set_user_nice(current, MAX_NICE);
 922
 923         do {
 924                 if ((torture_random(&rand) & 0xfffff) == 0)
 925                         schedule_timeout_uninterruptible(1);
 926
 927                 cxt.cur_ops->readlock(tid);
 928                 atomic_inc(&lock_is_read_held);
 929                 if (WARN_ON_ONCE(lock_is_write_held))
 930                         lrsp->n_lock_fail++; /* rare, but... */
 931
 932                 lrsp->n_lock_acquired++;
 933                 cxt.cur_ops->read_delay(&rand);
 934                 atomic_dec(&lock_is_read_held);
 935                 cxt.cur_ops->readunlock(tid);
 936
 937                 stutter_wait("lock_torture_reader");
 938         } while (!torture_must_stop());
 939         torture_kthread_stopping("lock_torture_reader");
 940         return 0;
 941 }
 942
 943 /*
 944  * Create an lock-torture-statistics message in the specified buffer.
 945  */
 946 static void __torture_print_stats(char *page,
 947                                   struct lock_stress_stats *statp, bool write)
 948 {
 949         long cur;
 950         bool fail = false;
 951         int i, n_stress;
 952         long max = 0, min = statp ? data_race(statp[0].n_lock_acquired) : 0;
 953         long long sum = 0;
 954
 955         n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress;
 956         for (i = 0; i < n_stress; i++) {
 957                 if (data_race(statp[i].n_lock_fail))
 958                         fail = true;
 959                 cur = data_race(statp[i].n_lock_acquired);
 960                 sum += cur;
 961                 if (max < cur)
 962                         max = cur;
 963                 if (min > cur)
 964                         min = cur;
 965         }
 966         page += sprintf(page,
 967                         "%s:  Total: %lld  Max/Min: %ld/%ld %s  Fail: %d %s\n",
 968                         write ? "Writes" : "Reads ",
 969                         sum, max, min,
 970                         !onoff_interval && max / 2 > min ? "???" : "",
 971                         fail, fail ? "!!!" : "");
 972         if (fail)
 973                 atomic_inc(&cxt.n_lock_torture_errors);
 974 }
 975
 976 /*
 977  * Print torture statistics.  Caller must ensure that there is only one
 978  * call to this function at a given time!!!  This is normally accomplished
 979  * by relying on the module system to only have one copy of the module
 980  * loaded, and then by giving the lock_torture_stats kthread full control
 981  * (or the init/cleanup functions when lock_torture_stats thread is not
 982  * running).
 983  */
 984 static void lock_torture_stats_print(void)
 985 {
 986         int size = cxt.nrealwriters_stress * 200 + 8192;
 987         char *buf;
 988
 989         if (cxt.cur_ops->readlock)
 990                 size += cxt.nrealreaders_stress * 200 + 8192;
 991
 992         buf = kmalloc(size, GFP_KERNEL);
 993         if (!buf) {
 994                 pr_err("lock_torture_stats_print: Out of memory, need: %d",
 995                        size);
 996                 return;
 997         }
 998
 999         __torture_print_stats(buf, cxt.lwsa, true);
1000         pr_alert("%s", buf);
1001         kfree(buf);
1002
1003         if (cxt.cur_ops->readlock) {
1004                 buf = kmalloc(size, GFP_KERNEL);
1005                 if (!buf) {
1006                         pr_err("lock_torture_stats_print: Out of memory, need: %d",
1007                                size);
1008                         return;
1009                 }
1010
1011                 __torture_print_stats(buf, cxt.lrsa, false);
1012                 pr_alert("%s", buf);
1013                 kfree(buf);
1014         }
1015 }
1016
1017 /*
1018  * Periodically prints torture statistics, if periodic statistics printing
1019  * was specified via the stat_interval module parameter.
1020  *
1021  * No need to worry about fullstop here, since this one doesn't reference
1022  * volatile state or register callbacks.
1023  */
1024 static int lock_torture_stats(void *arg)
1025 {
1026         VERBOSE_TOROUT_STRING("lock_torture_stats task started");
1027         do {
1028                 schedule_timeout_interruptible(stat_interval * HZ);
1029                 lock_torture_stats_print();
1030                 torture_shutdown_absorb("lock_torture_stats");
1031         } while (!torture_must_stop());
1032         torture_kthread_stopping("lock_torture_stats");
1033         return 0;
1034 }
1035
1036
1037 static inline void
1038 lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
1039                                 const char *tag)
1040 {
1041         static cpumask_t cpumask_all;
1042         cpumask_t *rcmp = cpumask_nonempty(bind_readers) ? bind_readers : &cpumask_all;
1043         cpumask_t *wcmp = cpumask_nonempty(bind_writers) ? bind_writers : &cpumask_all;
1044
1045         cpumask_setall(&cpumask_all);
1046         pr_alert("%s" TORTURE_FLAG
1047                  "--- %s%s: acq_writer_lim=%d bind_readers=%*pbl bind_writers=%*pbl call_rcu_chains=%d long_hold=%d nested_locks=%d nreaders_stress=%d nwriters_stress=%d onoff_holdoff=%d onoff_interval=%d rt_boost=%d rt_boost_factor=%d shuffle_interval=%d shutdown_secs=%d stat_interval=%d stutter=%d verbose=%d writer_fifo=%d\n",
1048                  torture_type, tag, cxt.debug_lock ? " [debug]": "",
1049                  acq_writer_lim, cpumask_pr_args(rcmp), cpumask_pr_args(wcmp),
1050                  call_rcu_chains, long_hold, nested_locks, cxt.nrealreaders_stress,
1051                  cxt.nrealwriters_stress, onoff_holdoff, onoff_interval, rt_boost,
1052                  rt_boost_factor, shuffle_interval, shutdown_secs, stat_interval, stutter,
1053                  verbose, writer_fifo);
1054 }
1055
1056 // If requested, maintain call_rcu() chains to keep a grace period always
1057 // in flight.  These increase the probability of getting an RCU CPU stall
1058 // warning and associated diagnostics when a locking primitive stalls.
1059
1060 static void call_rcu_chain_cb(struct rcu_head *rhp)
1061 {
1062         struct call_rcu_chain *crcp = container_of(rhp, struct call_rcu_chain, crc_rh);
1063
1064         if (!smp_load_acquire(&crcp->crc_stop)) {
1065                 (void)start_poll_synchronize_rcu(); // Start one grace period...
1066                 call_rcu(&crcp->crc_rh, call_rcu_chain_cb); // ... and later start another.
1067         }
1068 }
1069
1070 // Start the requested number of call_rcu() chains.
1071 static int call_rcu_chain_init(void)
1072 {
1073         int i;
1074
1075         if (call_rcu_chains <= 0)
1076                 return 0;
1077         call_rcu_chain_list = kcalloc(call_rcu_chains, sizeof(*call_rcu_chain_list), GFP_KERNEL);
1078         if (!call_rcu_chain_list)
1079                 return -ENOMEM;
1080         for (i = 0; i < call_rcu_chains; i++) {
1081                 call_rcu_chain_list[i].crc_stop = false;
1082                 call_rcu(&call_rcu_chain_list[i].crc_rh, call_rcu_chain_cb);
1083         }
1084         return 0;
1085 }
1086
1087 // Stop all of the call_rcu() chains.
1088 static void call_rcu_chain_cleanup(void)
1089 {
1090         int i;
1091
1092         if (!call_rcu_chain_list)
1093                 return;
1094         for (i = 0; i < call_rcu_chains; i++)
1095                 smp_store_release(&call_rcu_chain_list[i].crc_stop, true);
1096         rcu_barrier();
1097         kfree(call_rcu_chain_list);
1098         call_rcu_chain_list = NULL;
1099 }
1100
1101 static void lock_torture_cleanup(void)
1102 {
1103         int i;
1104
1105         if (torture_cleanup_begin())
1106                 return;
1107
1108         /*
1109          * Indicates early cleanup, meaning that the test has not run,
1110          * such as when passing bogus args when loading the module.
1111          * However cxt->cur_ops.init() may have been invoked, so beside
1112          * perform the underlying torture-specific cleanups, cur_ops.exit()
1113          * will be invoked if needed.
1114          */
1115         if (!cxt.lwsa && !cxt.lrsa)
1116                 goto end;
1117
1118         if (writer_tasks) {
1119                 for (i = 0; i < cxt.nrealwriters_stress; i++)
1120                         torture_stop_kthread(lock_torture_writer, writer_tasks[i]);
1121                 kfree(writer_tasks);
1122                 writer_tasks = NULL;
1123         }
1124
1125         if (reader_tasks) {
1126                 for (i = 0; i < cxt.nrealreaders_stress; i++)
1127                         torture_stop_kthread(lock_torture_reader,
1128                                              reader_tasks[i]);
1129                 kfree(reader_tasks);
1130                 reader_tasks = NULL;
1131         }
1132
1133         torture_stop_kthread(lock_torture_stats, stats_task);
1134         lock_torture_stats_print();  /* -After- the stats thread is stopped! */
1135
1136         if (atomic_read(&cxt.n_lock_torture_errors))
1137                 lock_torture_print_module_parms(cxt.cur_ops,
1138                                                 "End of test: FAILURE");
1139         else if (torture_onoff_failures())
1140                 lock_torture_print_module_parms(cxt.cur_ops,
1141                                                 "End of test: LOCK_HOTPLUG");
1142         else
1143                 lock_torture_print_module_parms(cxt.cur_ops,
1144                                                 "End of test: SUCCESS");
1145
1146         kfree(cxt.lwsa);
1147         cxt.lwsa = NULL;
1148         kfree(cxt.lrsa);
1149         cxt.lrsa = NULL;
1150
1151         call_rcu_chain_cleanup();
1152
1153 end:
1154         if (cxt.init_called) {
1155                 if (cxt.cur_ops->exit)
1156                         cxt.cur_ops->exit();
1157                 cxt.init_called = false;
1158         }
1159         torture_cleanup_end();
1160 }
1161
1162 static int __init lock_torture_init(void)
1163 {
1164         int i, j;
1165         int firsterr = 0;
1166         static struct lock_torture_ops *torture_ops[] = {
1167                 &lock_busted_ops,
1168                 &spin_lock_ops, &spin_lock_irq_ops,
1169                 &raw_spin_lock_ops, &raw_spin_lock_irq_ops,
1170                 &rw_lock_ops, &rw_lock_irq_ops,
1171                 &mutex_lock_ops,
1172                 &ww_mutex_lock_ops,
1173 #ifdef CONFIG_RT_MUTEXES
1174                 &rtmutex_lock_ops,
1175 #endif
1176                 &rwsem_lock_ops,
1177                 &percpu_rwsem_lock_ops,
1178         };
1179
1180         if (!torture_init_begin(torture_type, verbose))
1181                 return -EBUSY;
1182
1183         /* Process args and tell the world that the torturer is on the job. */
1184         for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1185                 cxt.cur_ops = torture_ops[i];
1186                 if (strcmp(torture_type, cxt.cur_ops->name) == 0)
1187                         break;
1188         }
1189         if (i == ARRAY_SIZE(torture_ops)) {
1190                 pr_alert("lock-torture: invalid torture type: \"%s\"\n",
1191                          torture_type);
1192                 pr_alert("lock-torture types:");
1193                 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1194                         pr_alert(" %s", torture_ops[i]->name);
1195                 pr_alert("\n");
1196                 firsterr = -EINVAL;
1197                 goto unwind;
1198         }
1199
1200         if (nwriters_stress == 0 &&
1201             (!cxt.cur_ops->readlock || nreaders_stress == 0)) {
1202                 pr_alert("lock-torture: must run at least one locking thread\n");
1203                 firsterr = -EINVAL;
1204                 goto unwind;
1205         }
1206
1207         if (nwriters_stress >= 0)
1208                 cxt.nrealwriters_stress = nwriters_stress;
1209         else
1210                 cxt.nrealwriters_stress = 2 * num_online_cpus();
1211
1212         if (cxt.cur_ops->init) {
1213                 cxt.cur_ops->init();
1214                 cxt.init_called = true;
1215         }
1216
1217 #ifdef CONFIG_DEBUG_MUTEXES
1218         if (str_has_prefix(torture_type, "mutex"))
1219                 cxt.debug_lock = true;
1220 #endif
1221 #ifdef CONFIG_DEBUG_RT_MUTEXES
1222         if (str_has_prefix(torture_type, "rtmutex"))
1223                 cxt.debug_lock = true;
1224 #endif
1225 #ifdef CONFIG_DEBUG_SPINLOCK
1226         if ((str_has_prefix(torture_type, "spin")) ||
1227             (str_has_prefix(torture_type, "rw_lock")))
1228                 cxt.debug_lock = true;
1229 #endif
1230
1231         /* Initialize the statistics so that each run gets its own numbers. */
1232         if (nwriters_stress) {
1233                 lock_is_write_held = false;
1234                 cxt.lwsa = kmalloc_array(cxt.nrealwriters_stress,
1235                                          sizeof(*cxt.lwsa),
1236                                          GFP_KERNEL);
1237                 if (cxt.lwsa == NULL) {
1238                         VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory");
1239                         firsterr = -ENOMEM;
1240                         goto unwind;
1241                 }
1242
1243                 for (i = 0; i < cxt.nrealwriters_stress; i++) {
1244                         cxt.lwsa[i].n_lock_fail = 0;
1245                         cxt.lwsa[i].n_lock_acquired = 0;
1246                 }
1247         }
1248
1249         if (cxt.cur_ops->readlock) {
1250                 if (nreaders_stress >= 0)
1251                         cxt.nrealreaders_stress = nreaders_stress;
1252                 else {
1253                         /*
1254                          * By default distribute evenly the number of
1255                          * readers and writers. We still run the same number
1256                          * of threads as the writer-only locks default.
1257                          */
1258                         if (nwriters_stress < 0) /* user doesn't care */
1259                                 cxt.nrealwriters_stress = num_online_cpus();
1260                         cxt.nrealreaders_stress = cxt.nrealwriters_stress;
1261                 }
1262
1263                 if (nreaders_stress) {
1264                         cxt.lrsa = kmalloc_array(cxt.nrealreaders_stress,
1265                                                  sizeof(*cxt.lrsa),
1266                                                  GFP_KERNEL);
1267                         if (cxt.lrsa == NULL) {
1268                                 VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory");
1269                                 firsterr = -ENOMEM;
1270                                 kfree(cxt.lwsa);
1271                                 cxt.lwsa = NULL;
1272                                 goto unwind;
1273                         }
1274
1275                         for (i = 0; i < cxt.nrealreaders_stress; i++) {
1276                                 cxt.lrsa[i].n_lock_fail = 0;
1277                                 cxt.lrsa[i].n_lock_acquired = 0;
1278                         }
1279                 }
1280         }
1281
1282         firsterr = call_rcu_chain_init();
1283         if (torture_init_error(firsterr))
1284                 goto unwind;
1285
1286         lock_torture_print_module_parms(cxt.cur_ops, "Start of test");
1287
1288         /* Prepare torture context. */
1289         if (onoff_interval > 0) {
1290                 firsterr = torture_onoff_init(onoff_holdoff * HZ,
1291                                               onoff_interval * HZ, NULL);
1292                 if (torture_init_error(firsterr))
1293                         goto unwind;
1294         }
1295         if (shuffle_interval > 0) {
1296                 firsterr = torture_shuffle_init(shuffle_interval);
1297                 if (torture_init_error(firsterr))
1298                         goto unwind;
1299         }
1300         if (shutdown_secs > 0) {
1301                 firsterr = torture_shutdown_init(shutdown_secs,
1302                                                  lock_torture_cleanup);
1303                 if (torture_init_error(firsterr))
1304                         goto unwind;
1305         }
1306         if (stutter > 0) {
1307                 firsterr = torture_stutter_init(stutter, stutter);
1308                 if (torture_init_error(firsterr))
1309                         goto unwind;
1310         }
1311
1312         if (nwriters_stress) {
1313                 writer_tasks = kcalloc(cxt.nrealwriters_stress,
1314                                        sizeof(writer_tasks[0]),
1315                                        GFP_KERNEL);
1316                 if (writer_tasks == NULL) {
1317                         TOROUT_ERRSTRING("writer_tasks: Out of memory");
1318                         firsterr = -ENOMEM;
1319                         goto unwind;
1320                 }
1321         }
1322
1323         /* cap nested_locks to MAX_NESTED_LOCKS */
1324         if (nested_locks > MAX_NESTED_LOCKS)
1325                 nested_locks = MAX_NESTED_LOCKS;
1326
1327         if (cxt.cur_ops->readlock) {
1328                 reader_tasks = kcalloc(cxt.nrealreaders_stress,
1329                                        sizeof(reader_tasks[0]),
1330                                        GFP_KERNEL);
1331                 if (reader_tasks == NULL) {
1332                         TOROUT_ERRSTRING("reader_tasks: Out of memory");
1333                         kfree(writer_tasks);
1334                         writer_tasks = NULL;
1335                         firsterr = -ENOMEM;
1336                         goto unwind;
1337                 }
1338         }
1339
1340         /*
1341          * Create the kthreads and start torturing (oh, those poor little locks).
1342          *
1343          * TODO: Note that we interleave writers with readers, giving writers a
1344          * slight advantage, by creating its kthread first. This can be modified
1345          * for very specific needs, or even let the user choose the policy, if
1346          * ever wanted.
1347          */
1348         for (i = 0, j = 0; i < cxt.nrealwriters_stress ||
1349                     j < cxt.nrealreaders_stress; i++, j++) {
1350                 if (i >= cxt.nrealwriters_stress)
1351                         goto create_reader;
1352
1353                 /* Create writer. */
1354                 firsterr = torture_create_kthread_cb(lock_torture_writer, &cxt.lwsa[i],
1355                                                      writer_tasks[i],
1356                                                      writer_fifo ? sched_set_fifo : NULL);
1357                 if (torture_init_error(firsterr))
1358                         goto unwind;
1359                 if (cpumask_nonempty(bind_writers))
1360                         torture_sched_setaffinity(writer_tasks[i]->pid, bind_writers);
1361
1362         create_reader:
1363                 if (cxt.cur_ops->readlock == NULL || (j >= cxt.nrealreaders_stress))
1364                         continue;
1365                 /* Create reader. */
1366                 firsterr = torture_create_kthread(lock_torture_reader, &cxt.lrsa[j],
1367                                                   reader_tasks[j]);
1368                 if (torture_init_error(firsterr))
1369                         goto unwind;
1370                 if (cpumask_nonempty(bind_readers))
1371                         torture_sched_setaffinity(reader_tasks[j]->pid, bind_readers);
1372         }
1373         if (stat_interval > 0) {
1374                 firsterr = torture_create_kthread(lock_torture_stats, NULL,
1375                                                   stats_task);
1376                 if (torture_init_error(firsterr))
1377                         goto unwind;
1378         }
1379         torture_init_end();
1380         return 0;
1381
1382 unwind:
1383         torture_init_end();
1384         lock_torture_cleanup();
1385         if (shutdown_secs) {
1386                 WARN_ON(!IS_MODULE(CONFIG_LOCK_TORTURE_TEST));
1387                 kernel_power_off();
1388         }
1389         return firsterr;
1390 }
1391
1392 module_init(lock_torture_init);
1393 module_exit(lock_torture_cleanup);