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  * Authors: Paul E. McKenney <paulmck@us.ibm.com>
  21  *          Davidlohr Bueso <dave@stgolabs.net>
  22  *      Based on kernel/rcu/torture.c.
  23  */
  24 #include <linux/kernel.h>
  25 #include <linux/module.h>
  26 #include <linux/kthread.h>
  27 #include <linux/sched/rt.h>
  28 #include <linux/spinlock.h>
  29 #include <linux/rwlock.h>
  30 #include <linux/mutex.h>
  31 #include <linux/rwsem.h>
  32 #include <linux/smp.h>
  33 #include <linux/interrupt.h>
  34 #include <linux/sched.h>
  35 #include <uapi/linux/sched/types.h>
  36 #include <linux/rtmutex.h>
  37 #include <linux/atomic.h>
  38 #include <linux/moduleparam.h>
  39 #include <linux/delay.h>
  40 #include <linux/slab.h>
  41 #include <linux/percpu-rwsem.h>
  42 #include <linux/torture.h>
  43
  44 MODULE_LICENSE("GPL");
  45 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
  46
  47 torture_param(int, nwriters_stress, -1,
  48              "Number of write-locking stress-test threads");
  49 torture_param(int, nreaders_stress, -1,
  50              "Number of read-locking stress-test threads");
  51 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
  52 torture_param(int, onoff_interval, 0,
  53              "Time between CPU hotplugs (s), 0=disable");
  54 torture_param(int, shuffle_interval, 3,
  55              "Number of jiffies between shuffles, 0=disable");
  56 torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable.");
  57 torture_param(int, stat_interval, 60,
  58              "Number of seconds between stats printk()s");
  59 torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
  60 torture_param(bool, verbose, true,
  61              "Enable verbose debugging printk()s");
  62
  63 static char *torture_type = "spin_lock";
  64 module_param(torture_type, charp, 0444);
  65 MODULE_PARM_DESC(torture_type,
  66                  "Type of lock to torture (spin_lock, spin_lock_irq, mutex_lock, ...)");
  67
  68 static struct task_struct *stats_task;
  69 static struct task_struct **writer_tasks;
  70 static struct task_struct **reader_tasks;
  71
  72 static bool lock_is_write_held;
  73 static bool lock_is_read_held;
  74
  75 struct lock_stress_stats {
  76         long n_lock_fail;
  77         long n_lock_acquired;
  78 };
  79
  80 int torture_runnable = IS_ENABLED(MODULE);
  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 (*task_boost)(struct torture_random_state *trsp);
  95         void (*writeunlock)(void);
  96         int (*readlock)(void);
  97         void (*read_delay)(struct torture_random_state *trsp);
  98         void (*readunlock)(void);
  99
 100         unsigned long flags; /* for irq spinlocks */
 101         const char *name;
 102 };
 103
 104 struct lock_torture_cxt {
 105         int nrealwriters_stress;
 106         int nrealreaders_stress;
 107         bool debug_lock;
 108         atomic_t n_lock_torture_errors;
 109         struct lock_torture_ops *cur_ops;
 110         struct lock_stress_stats *lwsa; /* writer statistics */
 111         struct lock_stress_stats *lrsa; /* reader statistics */
 112 };
 113 static struct lock_torture_cxt cxt = { 0, 0, false,
 114                                        ATOMIC_INIT(0),
 115                                        NULL, NULL};
 116 /*
 117  * Definitions for lock torture testing.
 118  */
 119
 120 static int torture_lock_busted_write_lock(void)
 121 {
 122         return 0;  /* BUGGY, do not use in real life!!! */
 123 }
 124
 125 static void torture_lock_busted_write_delay(struct torture_random_state *trsp)
 126 {
 127         const unsigned long longdelay_ms = 100;
 128
 129         /* We want a long delay occasionally to force massive contention.  */
 130         if (!(torture_random(trsp) %
 131               (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
 132                 mdelay(longdelay_ms);
 133 #ifdef CONFIG_PREEMPT
 134         if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
 135                 preempt_schedule();  /* Allow test to be preempted. */
 136 #endif
 137 }
 138
 139 static void torture_lock_busted_write_unlock(void)
 140 {
 141           /* BUGGY, do not use in real life!!! */
 142 }
 143
 144 static void torture_boost_dummy(struct torture_random_state *trsp)
 145 {
 146         /* Only rtmutexes care about priority */
 147 }
 148
 149 static struct lock_torture_ops lock_busted_ops = {
 150         .writelock      = torture_lock_busted_write_lock,
 151         .write_delay    = torture_lock_busted_write_delay,
 152         .task_boost     = torture_boost_dummy,
 153         .writeunlock    = torture_lock_busted_write_unlock,
 154         .readlock       = NULL,
 155         .read_delay     = NULL,
 156         .readunlock     = NULL,
 157         .name           = "lock_busted"
 158 };
 159
 160 static DEFINE_SPINLOCK(torture_spinlock);
 161
 162 static int torture_spin_lock_write_lock(void) __acquires(torture_spinlock)
 163 {
 164         spin_lock(&torture_spinlock);
 165         return 0;
 166 }
 167
 168 static void torture_spin_lock_write_delay(struct torture_random_state *trsp)
 169 {
 170         const unsigned long shortdelay_us = 2;
 171         const unsigned long longdelay_ms = 100;
 172
 173         /* We want a short delay mostly to emulate likely code, and
 174          * we want a long delay occasionally to force massive contention.
 175          */
 176         if (!(torture_random(trsp) %
 177               (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
 178                 mdelay(longdelay_ms);
 179         if (!(torture_random(trsp) %
 180               (cxt.nrealwriters_stress * 2 * shortdelay_us)))
 181                 udelay(shortdelay_us);
 182 #ifdef CONFIG_PREEMPT
 183         if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
 184                 preempt_schedule();  /* Allow test to be preempted. */
 185 #endif
 186 }
 187
 188 static void torture_spin_lock_write_unlock(void) __releases(torture_spinlock)
 189 {
 190         spin_unlock(&torture_spinlock);
 191 }
 192
 193 static struct lock_torture_ops spin_lock_ops = {
 194         .writelock      = torture_spin_lock_write_lock,
 195         .write_delay    = torture_spin_lock_write_delay,
 196         .task_boost     = torture_boost_dummy,
 197         .writeunlock    = torture_spin_lock_write_unlock,
 198         .readlock       = NULL,
 199         .read_delay     = NULL,
 200         .readunlock     = NULL,
 201         .name           = "spin_lock"
 202 };
 203
 204 static int torture_spin_lock_write_lock_irq(void)
 205 __acquires(torture_spinlock)
 206 {
 207         unsigned long flags;
 208
 209         spin_lock_irqsave(&torture_spinlock, flags);
 210         cxt.cur_ops->flags = flags;
 211         return 0;
 212 }
 213
 214 static void torture_lock_spin_write_unlock_irq(void)
 215 __releases(torture_spinlock)
 216 {
 217         spin_unlock_irqrestore(&torture_spinlock, cxt.cur_ops->flags);
 218 }
 219
 220 static struct lock_torture_ops spin_lock_irq_ops = {
 221         .writelock      = torture_spin_lock_write_lock_irq,
 222         .write_delay    = torture_spin_lock_write_delay,
 223         .task_boost     = torture_boost_dummy,
 224         .writeunlock    = torture_lock_spin_write_unlock_irq,
 225         .readlock       = NULL,
 226         .read_delay     = NULL,
 227         .readunlock     = NULL,
 228         .name           = "spin_lock_irq"
 229 };
 230
 231 static DEFINE_RWLOCK(torture_rwlock);
 232
 233 static int torture_rwlock_write_lock(void) __acquires(torture_rwlock)
 234 {
 235         write_lock(&torture_rwlock);
 236         return 0;
 237 }
 238
 239 static void torture_rwlock_write_delay(struct torture_random_state *trsp)
 240 {
 241         const unsigned long shortdelay_us = 2;
 242         const unsigned long longdelay_ms = 100;
 243
 244         /* We want a short delay mostly to emulate likely code, and
 245          * we want a long delay occasionally to force massive contention.
 246          */
 247         if (!(torture_random(trsp) %
 248               (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
 249                 mdelay(longdelay_ms);
 250         else
 251                 udelay(shortdelay_us);
 252 }
 253
 254 static void torture_rwlock_write_unlock(void) __releases(torture_rwlock)
 255 {
 256         write_unlock(&torture_rwlock);
 257 }
 258
 259 static int torture_rwlock_read_lock(void) __acquires(torture_rwlock)
 260 {
 261         read_lock(&torture_rwlock);
 262         return 0;
 263 }
 264
 265 static void torture_rwlock_read_delay(struct torture_random_state *trsp)
 266 {
 267         const unsigned long shortdelay_us = 10;
 268         const unsigned long longdelay_ms = 100;
 269
 270         /* We want a short delay mostly to emulate likely code, and
 271          * we want a long delay occasionally to force massive contention.
 272          */
 273         if (!(torture_random(trsp) %
 274               (cxt.nrealreaders_stress * 2000 * longdelay_ms)))
 275                 mdelay(longdelay_ms);
 276         else
 277                 udelay(shortdelay_us);
 278 }
 279
 280 static void torture_rwlock_read_unlock(void) __releases(torture_rwlock)
 281 {
 282         read_unlock(&torture_rwlock);
 283 }
 284
 285 static struct lock_torture_ops rw_lock_ops = {
 286         .writelock      = torture_rwlock_write_lock,
 287         .write_delay    = torture_rwlock_write_delay,
 288         .task_boost     = torture_boost_dummy,
 289         .writeunlock    = torture_rwlock_write_unlock,
 290         .readlock       = torture_rwlock_read_lock,
 291         .read_delay     = torture_rwlock_read_delay,
 292         .readunlock     = torture_rwlock_read_unlock,
 293         .name           = "rw_lock"
 294 };
 295
 296 static int torture_rwlock_write_lock_irq(void) __acquires(torture_rwlock)
 297 {
 298         unsigned long flags;
 299
 300         write_lock_irqsave(&torture_rwlock, flags);
 301         cxt.cur_ops->flags = flags;
 302         return 0;
 303 }
 304
 305 static void torture_rwlock_write_unlock_irq(void)
 306 __releases(torture_rwlock)
 307 {
 308         write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
 309 }
 310
 311 static int torture_rwlock_read_lock_irq(void) __acquires(torture_rwlock)
 312 {
 313         unsigned long flags;
 314
 315         read_lock_irqsave(&torture_rwlock, flags);
 316         cxt.cur_ops->flags = flags;
 317         return 0;
 318 }
 319
 320 static void torture_rwlock_read_unlock_irq(void)
 321 __releases(torture_rwlock)
 322 {
 323         read_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
 324 }
 325
 326 static struct lock_torture_ops rw_lock_irq_ops = {
 327         .writelock      = torture_rwlock_write_lock_irq,
 328         .write_delay    = torture_rwlock_write_delay,
 329         .task_boost     = torture_boost_dummy,
 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         .task_boost     = torture_boost_dummy,
 370         .writeunlock    = torture_mutex_unlock,
 371         .readlock       = NULL,
 372         .read_delay     = NULL,
 373         .readunlock     = NULL,
 374         .name           = "mutex_lock"
 375 };
 376
 377 #include <linux/ww_mutex.h>
 378 static DEFINE_WW_CLASS(torture_ww_class);
 379 static DEFINE_WW_MUTEX(torture_ww_mutex_0, &torture_ww_class);
 380 static DEFINE_WW_MUTEX(torture_ww_mutex_1, &torture_ww_class);
 381 static DEFINE_WW_MUTEX(torture_ww_mutex_2, &torture_ww_class);
 382
 383 static int torture_ww_mutex_lock(void)
 384 __acquires(torture_ww_mutex_0)
 385 __acquires(torture_ww_mutex_1)
 386 __acquires(torture_ww_mutex_2)
 387 {
 388         LIST_HEAD(list);
 389         struct reorder_lock {
 390                 struct list_head link;
 391                 struct ww_mutex *lock;
 392         } locks[3], *ll, *ln;
 393         struct ww_acquire_ctx ctx;
 394
 395         locks[0].lock = &torture_ww_mutex_0;
 396         list_add(&locks[0].link, &list);
 397
 398         locks[1].lock = &torture_ww_mutex_1;
 399         list_add(&locks[1].link, &list);
 400
 401         locks[2].lock = &torture_ww_mutex_2;
 402         list_add(&locks[2].link, &list);
 403
 404         ww_acquire_init(&ctx, &torture_ww_class);
 405
 406         list_for_each_entry(ll, &list, link) {
 407                 int err;
 408
 409                 err = ww_mutex_lock(ll->lock, &ctx);
 410                 if (!err)
 411                         continue;
 412
 413                 ln = ll;
 414                 list_for_each_entry_continue_reverse(ln, &list, link)
 415                         ww_mutex_unlock(ln->lock);
 416
 417                 if (err != -EDEADLK)
 418                         return err;
 419
 420                 ww_mutex_lock_slow(ll->lock, &ctx);
 421                 list_move(&ll->link, &list);
 422         }
 423
 424         ww_acquire_fini(&ctx);
 425         return 0;
 426 }
 427
 428 static void torture_ww_mutex_unlock(void)
 429 __releases(torture_ww_mutex_0)
 430 __releases(torture_ww_mutex_1)
 431 __releases(torture_ww_mutex_2)
 432 {
 433         ww_mutex_unlock(&torture_ww_mutex_0);
 434         ww_mutex_unlock(&torture_ww_mutex_1);
 435         ww_mutex_unlock(&torture_ww_mutex_2);
 436 }
 437
 438 static struct lock_torture_ops ww_mutex_lock_ops = {
 439         .writelock      = torture_ww_mutex_lock,
 440         .write_delay    = torture_mutex_delay,
 441         .task_boost     = torture_boost_dummy,
 442         .writeunlock    = torture_ww_mutex_unlock,
 443         .readlock       = NULL,
 444         .read_delay     = NULL,
 445         .readunlock     = NULL,
 446         .name           = "ww_mutex_lock"
 447 };
 448
 449 #ifdef CONFIG_RT_MUTEXES
 450 static DEFINE_RT_MUTEX(torture_rtmutex);
 451
 452 static int torture_rtmutex_lock(void) __acquires(torture_rtmutex)
 453 {
 454         rt_mutex_lock(&torture_rtmutex);
 455         return 0;
 456 }
 457
 458 static void torture_rtmutex_boost(struct torture_random_state *trsp)
 459 {
 460         int policy;
 461         struct sched_param param;
 462         const unsigned int factor = 50000; /* yes, quite arbitrary */
 463
 464         if (!rt_task(current)) {
 465                 /*
 466                  * Boost priority once every ~50k operations. When the
 467                  * task tries to take the lock, the rtmutex it will account
 468                  * for the new priority, and do any corresponding pi-dance.
 469                  */
 470                 if (trsp && !(torture_random(trsp) %
 471                               (cxt.nrealwriters_stress * factor))) {
 472                         policy = SCHED_FIFO;
 473                         param.sched_priority = MAX_RT_PRIO - 1;
 474                 } else /* common case, do nothing */
 475                         return;
 476         } else {
 477                 /*
 478                  * The task will remain boosted for another ~500k operations,
 479                  * then restored back to its original prio, and so forth.
 480                  *
 481                  * When @trsp is nil, we want to force-reset the task for
 482                  * stopping the kthread.
 483                  */
 484                 if (!trsp || !(torture_random(trsp) %
 485                                (cxt.nrealwriters_stress * factor * 2))) {
 486                         policy = SCHED_NORMAL;
 487                         param.sched_priority = 0;
 488                 } else /* common case, do nothing */
 489                         return;
 490         }
 491
 492         sched_setscheduler_nocheck(current, policy, &param);
 493 }
 494
 495 static void torture_rtmutex_delay(struct torture_random_state *trsp)
 496 {
 497         const unsigned long shortdelay_us = 2;
 498         const unsigned long longdelay_ms = 100;
 499
 500         /*
 501          * We want a short delay mostly to emulate likely code, and
 502          * we want a long delay occasionally to force massive contention.
 503          */
 504         if (!(torture_random(trsp) %
 505               (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
 506                 mdelay(longdelay_ms);
 507         if (!(torture_random(trsp) %
 508               (cxt.nrealwriters_stress * 2 * shortdelay_us)))
 509                 udelay(shortdelay_us);
 510 #ifdef CONFIG_PREEMPT
 511         if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
 512                 preempt_schedule();  /* Allow test to be preempted. */
 513 #endif
 514 }
 515
 516 static void torture_rtmutex_unlock(void) __releases(torture_rtmutex)
 517 {
 518         rt_mutex_unlock(&torture_rtmutex);
 519 }
 520
 521 static struct lock_torture_ops rtmutex_lock_ops = {
 522         .writelock      = torture_rtmutex_lock,
 523         .write_delay    = torture_rtmutex_delay,
 524         .task_boost     = torture_rtmutex_boost,
 525         .writeunlock    = torture_rtmutex_unlock,
 526         .readlock       = NULL,
 527         .read_delay     = NULL,
 528         .readunlock     = NULL,
 529         .name           = "rtmutex_lock"
 530 };
 531 #endif
 532
 533 static DECLARE_RWSEM(torture_rwsem);
 534 static int torture_rwsem_down_write(void) __acquires(torture_rwsem)
 535 {
 536         down_write(&torture_rwsem);
 537         return 0;
 538 }
 539
 540 static void torture_rwsem_write_delay(struct torture_random_state *trsp)
 541 {
 542         const unsigned long longdelay_ms = 100;
 543
 544         /* We want a long delay occasionally to force massive contention.  */
 545         if (!(torture_random(trsp) %
 546               (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
 547                 mdelay(longdelay_ms * 10);
 548         else
 549                 mdelay(longdelay_ms / 10);
 550 #ifdef CONFIG_PREEMPT
 551         if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
 552                 preempt_schedule();  /* Allow test to be preempted. */
 553 #endif
 554 }
 555
 556 static void torture_rwsem_up_write(void) __releases(torture_rwsem)
 557 {
 558         up_write(&torture_rwsem);
 559 }
 560
 561 static int torture_rwsem_down_read(void) __acquires(torture_rwsem)
 562 {
 563         down_read(&torture_rwsem);
 564         return 0;
 565 }
 566
 567 static void torture_rwsem_read_delay(struct torture_random_state *trsp)
 568 {
 569         const unsigned long longdelay_ms = 100;
 570
 571         /* We want a long delay occasionally to force massive contention.  */
 572         if (!(torture_random(trsp) %
 573               (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
 574                 mdelay(longdelay_ms * 2);
 575         else
 576                 mdelay(longdelay_ms / 2);
 577 #ifdef CONFIG_PREEMPT
 578         if (!(torture_random(trsp) % (cxt.nrealreaders_stress * 20000)))
 579                 preempt_schedule();  /* Allow test to be preempted. */
 580 #endif
 581 }
 582
 583 static void torture_rwsem_up_read(void) __releases(torture_rwsem)
 584 {
 585         up_read(&torture_rwsem);
 586 }
 587
 588 static struct lock_torture_ops rwsem_lock_ops = {
 589         .writelock      = torture_rwsem_down_write,
 590         .write_delay    = torture_rwsem_write_delay,
 591         .task_boost     = torture_boost_dummy,
 592         .writeunlock    = torture_rwsem_up_write,
 593         .readlock       = torture_rwsem_down_read,
 594         .read_delay     = torture_rwsem_read_delay,
 595         .readunlock     = torture_rwsem_up_read,
 596         .name           = "rwsem_lock"
 597 };
 598
 599 #include <linux/percpu-rwsem.h>
 600 static struct percpu_rw_semaphore pcpu_rwsem;
 601
 602 void torture_percpu_rwsem_init(void)
 603 {
 604         BUG_ON(percpu_init_rwsem(&pcpu_rwsem));
 605 }
 606
 607 static int torture_percpu_rwsem_down_write(void) __acquires(pcpu_rwsem)
 608 {
 609         percpu_down_write(&pcpu_rwsem);
 610         return 0;
 611 }
 612
 613 static void torture_percpu_rwsem_up_write(void) __releases(pcpu_rwsem)
 614 {
 615         percpu_up_write(&pcpu_rwsem);
 616 }
 617
 618 static int torture_percpu_rwsem_down_read(void) __acquires(pcpu_rwsem)
 619 {
 620         percpu_down_read(&pcpu_rwsem);
 621         return 0;
 622 }
 623
 624 static void torture_percpu_rwsem_up_read(void) __releases(pcpu_rwsem)
 625 {
 626         percpu_up_read(&pcpu_rwsem);
 627 }
 628
 629 static struct lock_torture_ops percpu_rwsem_lock_ops = {
 630         .init           = torture_percpu_rwsem_init,
 631         .writelock      = torture_percpu_rwsem_down_write,
 632         .write_delay    = torture_rwsem_write_delay,
 633         .task_boost     = torture_boost_dummy,
 634         .writeunlock    = torture_percpu_rwsem_up_write,
 635         .readlock       = torture_percpu_rwsem_down_read,
 636         .read_delay     = torture_rwsem_read_delay,
 637         .readunlock     = torture_percpu_rwsem_up_read,
 638         .name           = "percpu_rwsem_lock"
 639 };
 640
 641 /*
 642  * Lock torture writer kthread.  Repeatedly acquires and releases
 643  * the lock, checking for duplicate acquisitions.
 644  */
 645 static int lock_torture_writer(void *arg)
 646 {
 647         struct lock_stress_stats *lwsp = arg;
 648         static DEFINE_TORTURE_RANDOM(rand);
 649
 650         VERBOSE_TOROUT_STRING("lock_torture_writer task started");
 651         set_user_nice(current, MAX_NICE);
 652
 653         do {
 654                 if ((torture_random(&rand) & 0xfffff) == 0)
 655                         schedule_timeout_uninterruptible(1);
 656
 657                 cxt.cur_ops->task_boost(&rand);
 658                 cxt.cur_ops->writelock();
 659                 if (WARN_ON_ONCE(lock_is_write_held))
 660                         lwsp->n_lock_fail++;
 661                 lock_is_write_held = 1;
 662                 if (WARN_ON_ONCE(lock_is_read_held))
 663                         lwsp->n_lock_fail++; /* rare, but... */
 664
 665                 lwsp->n_lock_acquired++;
 666                 cxt.cur_ops->write_delay(&rand);
 667                 lock_is_write_held = 0;
 668                 cxt.cur_ops->writeunlock();
 669
 670                 stutter_wait("lock_torture_writer");
 671         } while (!torture_must_stop());
 672
 673         cxt.cur_ops->task_boost(NULL); /* reset prio */
 674         torture_kthread_stopping("lock_torture_writer");
 675         return 0;
 676 }
 677
 678 /*
 679  * Lock torture reader kthread.  Repeatedly acquires and releases
 680  * the reader lock.
 681  */
 682 static int lock_torture_reader(void *arg)
 683 {
 684         struct lock_stress_stats *lrsp = arg;
 685         static DEFINE_TORTURE_RANDOM(rand);
 686
 687         VERBOSE_TOROUT_STRING("lock_torture_reader task started");
 688         set_user_nice(current, MAX_NICE);
 689
 690         do {
 691                 if ((torture_random(&rand) & 0xfffff) == 0)
 692                         schedule_timeout_uninterruptible(1);
 693
 694                 cxt.cur_ops->readlock();
 695                 lock_is_read_held = 1;
 696                 if (WARN_ON_ONCE(lock_is_write_held))
 697                         lrsp->n_lock_fail++; /* rare, but... */
 698
 699                 lrsp->n_lock_acquired++;
 700                 cxt.cur_ops->read_delay(&rand);
 701                 lock_is_read_held = 0;
 702                 cxt.cur_ops->readunlock();
 703
 704                 stutter_wait("lock_torture_reader");
 705         } while (!torture_must_stop());
 706         torture_kthread_stopping("lock_torture_reader");
 707         return 0;
 708 }
 709
 710 /*
 711  * Create an lock-torture-statistics message in the specified buffer.
 712  */
 713 static void __torture_print_stats(char *page,
 714                                   struct lock_stress_stats *statp, bool write)
 715 {
 716         bool fail = 0;
 717         int i, n_stress;
 718         long max = 0, min = statp ? statp[0].n_lock_acquired : 0;
 719         long long sum = 0;
 720
 721         n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress;
 722         for (i = 0; i < n_stress; i++) {
 723                 if (statp[i].n_lock_fail)
 724                         fail = true;
 725                 sum += statp[i].n_lock_acquired;
 726                 if (max < statp[i].n_lock_acquired)
 727                         max = statp[i].n_lock_acquired;
 728                 if (min > statp[i].n_lock_acquired)
 729                         min = statp[i].n_lock_acquired;
 730         }
 731         page += sprintf(page,
 732                         "%s:  Total: %lld  Max/Min: %ld/%ld %s  Fail: %d %s\n",
 733                         write ? "Writes" : "Reads ",
 734                         sum, max, min, max / 2 > min ? "???" : "",
 735                         fail, fail ? "!!!" : "");
 736         if (fail)
 737                 atomic_inc(&cxt.n_lock_torture_errors);
 738 }
 739
 740 /*
 741  * Print torture statistics.  Caller must ensure that there is only one
 742  * call to this function at a given time!!!  This is normally accomplished
 743  * by relying on the module system to only have one copy of the module
 744  * loaded, and then by giving the lock_torture_stats kthread full control
 745  * (or the init/cleanup functions when lock_torture_stats thread is not
 746  * running).
 747  */
 748 static void lock_torture_stats_print(void)
 749 {
 750         int size = cxt.nrealwriters_stress * 200 + 8192;
 751         char *buf;
 752
 753         if (cxt.cur_ops->readlock)
 754                 size += cxt.nrealreaders_stress * 200 + 8192;
 755
 756         buf = kmalloc(size, GFP_KERNEL);
 757         if (!buf) {
 758                 pr_err("lock_torture_stats_print: Out of memory, need: %d",
 759                        size);
 760                 return;
 761         }
 762
 763         __torture_print_stats(buf, cxt.lwsa, true);
 764         pr_alert("%s", buf);
 765         kfree(buf);
 766
 767         if (cxt.cur_ops->readlock) {
 768                 buf = kmalloc(size, GFP_KERNEL);
 769                 if (!buf) {
 770                         pr_err("lock_torture_stats_print: Out of memory, need: %d",
 771                                size);
 772                         return;
 773                 }
 774
 775                 __torture_print_stats(buf, cxt.lrsa, false);
 776                 pr_alert("%s", buf);
 777                 kfree(buf);
 778         }
 779 }
 780
 781 /*
 782  * Periodically prints torture statistics, if periodic statistics printing
 783  * was specified via the stat_interval module parameter.
 784  *
 785  * No need to worry about fullstop here, since this one doesn't reference
 786  * volatile state or register callbacks.
 787  */
 788 static int lock_torture_stats(void *arg)
 789 {
 790         VERBOSE_TOROUT_STRING("lock_torture_stats task started");
 791         do {
 792                 schedule_timeout_interruptible(stat_interval * HZ);
 793                 lock_torture_stats_print();
 794                 torture_shutdown_absorb("lock_torture_stats");
 795         } while (!torture_must_stop());
 796         torture_kthread_stopping("lock_torture_stats");
 797         return 0;
 798 }
 799
 800 static inline void
 801 lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
 802                                 const char *tag)
 803 {
 804         pr_alert("%s" TORTURE_FLAG
 805                  "--- %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",
 806                  torture_type, tag, cxt.debug_lock ? " [debug]": "",
 807                  cxt.nrealwriters_stress, cxt.nrealreaders_stress, stat_interval,
 808                  verbose, shuffle_interval, stutter, shutdown_secs,
 809                  onoff_interval, onoff_holdoff);
 810 }
 811
 812 static void lock_torture_cleanup(void)
 813 {
 814         int i;
 815
 816         if (torture_cleanup_begin())
 817                 return;
 818
 819         /*
 820          * Indicates early cleanup, meaning that the test has not run,
 821          * such as when passing bogus args when loading the module. As
 822          * such, only perform the underlying torture-specific cleanups,
 823          * and avoid anything related to locktorture.
 824          */
 825         if (!cxt.lwsa && !cxt.lrsa)
 826                 goto end;
 827
 828         if (writer_tasks) {
 829                 for (i = 0; i < cxt.nrealwriters_stress; i++)
 830                         torture_stop_kthread(lock_torture_writer,
 831                                              writer_tasks[i]);
 832                 kfree(writer_tasks);
 833                 writer_tasks = NULL;
 834         }
 835
 836         if (reader_tasks) {
 837                 for (i = 0; i < cxt.nrealreaders_stress; i++)
 838                         torture_stop_kthread(lock_torture_reader,
 839                                              reader_tasks[i]);
 840                 kfree(reader_tasks);
 841                 reader_tasks = NULL;
 842         }
 843
 844         torture_stop_kthread(lock_torture_stats, stats_task);
 845         lock_torture_stats_print();  /* -After- the stats thread is stopped! */
 846
 847         if (atomic_read(&cxt.n_lock_torture_errors))
 848                 lock_torture_print_module_parms(cxt.cur_ops,
 849                                                 "End of test: FAILURE");
 850         else if (torture_onoff_failures())
 851                 lock_torture_print_module_parms(cxt.cur_ops,
 852                                                 "End of test: LOCK_HOTPLUG");
 853         else
 854                 lock_torture_print_module_parms(cxt.cur_ops,
 855                                                 "End of test: SUCCESS");
 856
 857         kfree(cxt.lwsa);
 858         kfree(cxt.lrsa);
 859
 860 end:
 861         torture_cleanup_end();
 862 }
 863
 864 static int __init lock_torture_init(void)
 865 {
 866         int i, j;
 867         int firsterr = 0;
 868         static struct lock_torture_ops *torture_ops[] = {
 869                 &lock_busted_ops,
 870                 &spin_lock_ops, &spin_lock_irq_ops,
 871                 &rw_lock_ops, &rw_lock_irq_ops,
 872                 &mutex_lock_ops,
 873                 &ww_mutex_lock_ops,
 874 #ifdef CONFIG_RT_MUTEXES
 875                 &rtmutex_lock_ops,
 876 #endif
 877                 &rwsem_lock_ops,
 878                 &percpu_rwsem_lock_ops,
 879         };
 880
 881         if (!torture_init_begin(torture_type, verbose, &torture_runnable))
 882                 return -EBUSY;
 883
 884         /* Process args and tell the world that the torturer is on the job. */
 885         for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
 886                 cxt.cur_ops = torture_ops[i];
 887                 if (strcmp(torture_type, cxt.cur_ops->name) == 0)
 888                         break;
 889         }
 890         if (i == ARRAY_SIZE(torture_ops)) {
 891                 pr_alert("lock-torture: invalid torture type: \"%s\"\n",
 892                          torture_type);
 893                 pr_alert("lock-torture types:");
 894                 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
 895                         pr_alert(" %s", torture_ops[i]->name);
 896                 pr_alert("\n");
 897                 firsterr = -EINVAL;
 898                 goto unwind;
 899         }
 900
 901         if (nwriters_stress == 0 && nreaders_stress == 0) {
 902                 pr_alert("lock-torture: must run at least one locking thread\n");
 903                 firsterr = -EINVAL;
 904                 goto unwind;
 905         }
 906
 907         if (cxt.cur_ops->init)
 908                 cxt.cur_ops->init();
 909
 910         if (nwriters_stress >= 0)
 911                 cxt.nrealwriters_stress = nwriters_stress;
 912         else
 913                 cxt.nrealwriters_stress = 2 * num_online_cpus();
 914
 915 #ifdef CONFIG_DEBUG_MUTEXES
 916         if (strncmp(torture_type, "mutex", 5) == 0)
 917                 cxt.debug_lock = true;
 918 #endif
 919 #ifdef CONFIG_DEBUG_RT_MUTEXES
 920         if (strncmp(torture_type, "rtmutex", 7) == 0)
 921                 cxt.debug_lock = true;
 922 #endif
 923 #ifdef CONFIG_DEBUG_SPINLOCK
 924         if ((strncmp(torture_type, "spin", 4) == 0) ||
 925             (strncmp(torture_type, "rw_lock", 7) == 0))
 926                 cxt.debug_lock = true;
 927 #endif
 928
 929         /* Initialize the statistics so that each run gets its own numbers. */
 930         if (nwriters_stress) {
 931                 lock_is_write_held = 0;
 932                 cxt.lwsa = kmalloc(sizeof(*cxt.lwsa) * cxt.nrealwriters_stress, GFP_KERNEL);
 933                 if (cxt.lwsa == NULL) {
 934                         VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory");
 935                         firsterr = -ENOMEM;
 936                         goto unwind;
 937                 }
 938
 939                 for (i = 0; i < cxt.nrealwriters_stress; i++) {
 940                         cxt.lwsa[i].n_lock_fail = 0;
 941                         cxt.lwsa[i].n_lock_acquired = 0;
 942                 }
 943         }
 944
 945         if (cxt.cur_ops->readlock) {
 946                 if (nreaders_stress >= 0)
 947                         cxt.nrealreaders_stress = nreaders_stress;
 948                 else {
 949                         /*
 950                          * By default distribute evenly the number of
 951                          * readers and writers. We still run the same number
 952                          * of threads as the writer-only locks default.
 953                          */
 954                         if (nwriters_stress < 0) /* user doesn't care */
 955                                 cxt.nrealwriters_stress = num_online_cpus();
 956                         cxt.nrealreaders_stress = cxt.nrealwriters_stress;
 957                 }
 958
 959                 if (nreaders_stress) {
 960                         lock_is_read_held = 0;
 961                         cxt.lrsa = kmalloc(sizeof(*cxt.lrsa) * cxt.nrealreaders_stress, GFP_KERNEL);
 962                         if (cxt.lrsa == NULL) {
 963                                 VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory");
 964                                 firsterr = -ENOMEM;
 965                                 kfree(cxt.lwsa);
 966                                 cxt.lwsa = NULL;
 967                                 goto unwind;
 968                         }
 969
 970                         for (i = 0; i < cxt.nrealreaders_stress; i++) {
 971                                 cxt.lrsa[i].n_lock_fail = 0;
 972                                 cxt.lrsa[i].n_lock_acquired = 0;
 973                         }
 974                 }
 975         }
 976
 977         lock_torture_print_module_parms(cxt.cur_ops, "Start of test");
 978
 979         /* Prepare torture context. */
 980         if (onoff_interval > 0) {
 981                 firsterr = torture_onoff_init(onoff_holdoff * HZ,
 982                                               onoff_interval * HZ);
 983                 if (firsterr)
 984                         goto unwind;
 985         }
 986         if (shuffle_interval > 0) {
 987                 firsterr = torture_shuffle_init(shuffle_interval);
 988                 if (firsterr)
 989                         goto unwind;
 990         }
 991         if (shutdown_secs > 0) {
 992                 firsterr = torture_shutdown_init(shutdown_secs,
 993                                                  lock_torture_cleanup);
 994                 if (firsterr)
 995                         goto unwind;
 996         }
 997         if (stutter > 0) {
 998                 firsterr = torture_stutter_init(stutter);
 999                 if (firsterr)
1000                         goto unwind;
1001         }
1002
1003         if (nwriters_stress) {
1004                 writer_tasks = kzalloc(cxt.nrealwriters_stress * sizeof(writer_tasks[0]),
1005                                        GFP_KERNEL);
1006                 if (writer_tasks == NULL) {
1007                         VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory");
1008                         firsterr = -ENOMEM;
1009                         goto unwind;
1010                 }
1011         }
1012
1013         if (cxt.cur_ops->readlock) {
1014                 reader_tasks = kzalloc(cxt.nrealreaders_stress * sizeof(reader_tasks[0]),
1015                                        GFP_KERNEL);
1016                 if (reader_tasks == NULL) {
1017                         VERBOSE_TOROUT_ERRSTRING("reader_tasks: Out of memory");
1018                         kfree(writer_tasks);
1019                         writer_tasks = NULL;
1020                         firsterr = -ENOMEM;
1021                         goto unwind;
1022                 }
1023         }
1024
1025         /*
1026          * Create the kthreads and start torturing (oh, those poor little locks).
1027          *
1028          * TODO: Note that we interleave writers with readers, giving writers a
1029          * slight advantage, by creating its kthread first. This can be modified
1030          * for very specific needs, or even let the user choose the policy, if
1031          * ever wanted.
1032          */
1033         for (i = 0, j = 0; i < cxt.nrealwriters_stress ||
1034                     j < cxt.nrealreaders_stress; i++, j++) {
1035                 if (i >= cxt.nrealwriters_stress)
1036                         goto create_reader;
1037
1038                 /* Create writer. */
1039                 firsterr = torture_create_kthread(lock_torture_writer, &cxt.lwsa[i],
1040                                                   writer_tasks[i]);
1041                 if (firsterr)
1042                         goto unwind;
1043
1044         create_reader:
1045                 if (cxt.cur_ops->readlock == NULL || (j >= cxt.nrealreaders_stress))
1046                         continue;
1047                 /* Create reader. */
1048                 firsterr = torture_create_kthread(lock_torture_reader, &cxt.lrsa[j],
1049                                                   reader_tasks[j]);
1050                 if (firsterr)
1051                         goto unwind;
1052         }
1053         if (stat_interval > 0) {
1054                 firsterr = torture_create_kthread(lock_torture_stats, NULL,
1055                                                   stats_task);
1056                 if (firsterr)
1057                         goto unwind;
1058         }
1059         torture_init_end();
1060         return 0;
1061
1062 unwind:
1063         torture_init_end();
1064         lock_torture_cleanup();
1065         return firsterr;
1066 }
1067
1068 module_init(lock_torture_init);
1069 module_exit(lock_torture_cleanup);