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
  25 #define pr_fmt(fmt) fmt
  26
  27 #include <linux/kernel.h>
  28 #include <linux/module.h>
  29 #include <linux/kthread.h>
  30 #include <linux/sched/rt.h>
  31 #include <linux/spinlock.h>
  32 #include <linux/rwlock.h>
  33 #include <linux/mutex.h>
  34 #include <linux/rwsem.h>
  35 #include <linux/smp.h>
  36 #include <linux/interrupt.h>
  37 #include <linux/sched.h>
  38 #include <uapi/linux/sched/types.h>
  39 #include <linux/rtmutex.h>
  40 #include <linux/atomic.h>
  41 #include <linux/moduleparam.h>
  42 #include <linux/delay.h>
  43 #include <linux/slab.h>
  44 #include <linux/percpu-rwsem.h>
  45 #include <linux/torture.h>
  46
  47 MODULE_LICENSE("GPL");
  48 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
  49
  50 torture_param(int, nwriters_stress, -1,
  51              "Number of write-locking stress-test threads");
  52 torture_param(int, nreaders_stress, -1,
  53              "Number of read-locking stress-test threads");
  54 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
  55 torture_param(int, onoff_interval, 0,
  56              "Time between CPU hotplugs (s), 0=disable");
  57 torture_param(int, shuffle_interval, 3,
  58              "Number of jiffies between shuffles, 0=disable");
  59 torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable.");
  60 torture_param(int, stat_interval, 60,
  61              "Number of seconds between stats printk()s");
  62 torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
  63 torture_param(int, verbose, 1,
  64              "Enable verbose debugging printk()s");
  65
  66 static char *torture_type = "spin_lock";
  67 module_param(torture_type, charp, 0444);
  68 MODULE_PARM_DESC(torture_type,
  69                  "Type of lock to torture (spin_lock, spin_lock_irq, mutex_lock, ...)");
  70
  71 static struct task_struct *stats_task;
  72 static struct task_struct **writer_tasks;
  73 static struct task_struct **reader_tasks;
  74
  75 static bool lock_is_write_held;
  76 static bool lock_is_read_held;
  77
  78 struct lock_stress_stats {
  79         long n_lock_fail;
  80         long n_lock_acquired;
  81 };
  82
  83 /* Forward reference. */
  84 static void lock_torture_cleanup(void);
  85
  86 /*
  87  * Operations vector for selecting different types of tests.
  88  */
  89 struct lock_torture_ops {
  90         void (*init)(void);
  91         int (*writelock)(void);
  92         void (*write_delay)(struct torture_random_state *trsp);
  93         void (*task_boost)(struct torture_random_state *trsp);
  94         void (*writeunlock)(void);
  95         int (*readlock)(void);
  96         void (*read_delay)(struct torture_random_state *trsp);
  97         void (*readunlock)(void);
  98
  99         unsigned long flags; /* for irq spinlocks */
 100         const char *name;
 101 };
 102
 103 struct lock_torture_cxt {
 104         int nrealwriters_stress;
 105         int nrealreaders_stress;
 106         bool debug_lock;
 107         atomic_t n_lock_torture_errors;
 108         struct lock_torture_ops *cur_ops;
 109         struct lock_stress_stats *lwsa; /* writer statistics */
 110         struct lock_stress_stats *lrsa; /* reader statistics */
 111 };
 112 static struct lock_torture_cxt cxt = { 0, 0, false,
 113                                        ATOMIC_INIT(0),
 114                                        NULL, NULL};
 115 /*
 116  * Definitions for lock torture testing.
 117  */
 118
 119 static int torture_lock_busted_write_lock(void)
 120 {
 121         return 0;  /* BUGGY, do not use in real life!!! */
 122 }
 123
 124 static void torture_lock_busted_write_delay(struct torture_random_state *trsp)
 125 {
 126         const unsigned long longdelay_ms = 100;
 127
 128         /* We want a long delay occasionally to force massive contention.  */
 129         if (!(torture_random(trsp) %
 130               (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
 131                 mdelay(longdelay_ms);
 132         if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
 133                 torture_preempt_schedule();  /* Allow test to be preempted. */
 134 }
 135
 136 static void torture_lock_busted_write_unlock(void)
 137 {
 138           /* BUGGY, do not use in real life!!! */
 139 }
 140
 141 static void torture_boost_dummy(struct torture_random_state *trsp)
 142 {
 143         /* Only rtmutexes care about priority */
 144 }
 145
 146 static struct lock_torture_ops lock_busted_ops = {
 147         .writelock      = torture_lock_busted_write_lock,
 148         .write_delay    = torture_lock_busted_write_delay,
 149         .task_boost     = torture_boost_dummy,
 150         .writeunlock    = torture_lock_busted_write_unlock,
 151         .readlock       = NULL,
 152         .read_delay     = NULL,
 153         .readunlock     = NULL,
 154         .name           = "lock_busted"
 155 };
 156
 157 static DEFINE_SPINLOCK(torture_spinlock);
 158
 159 static int torture_spin_lock_write_lock(void) __acquires(torture_spinlock)
 160 {
 161         spin_lock(&torture_spinlock);
 162         return 0;
 163 }
 164
 165 static void torture_spin_lock_write_delay(struct torture_random_state *trsp)
 166 {
 167         const unsigned long shortdelay_us = 2;
 168         const unsigned long longdelay_ms = 100;
 169
 170         /* We want a short delay mostly to emulate likely code, and
 171          * we want a long delay occasionally to force massive contention.
 172          */
 173         if (!(torture_random(trsp) %
 174               (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
 175                 mdelay(longdelay_ms);
 176         if (!(torture_random(trsp) %
 177               (cxt.nrealwriters_stress * 2 * shortdelay_us)))
 178                 udelay(shortdelay_us);
 179         if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
 180                 torture_preempt_schedule();  /* Allow test to be preempted. */
 181 }
 182
 183 static void torture_spin_lock_write_unlock(void) __releases(torture_spinlock)
 184 {
 185         spin_unlock(&torture_spinlock);
 186 }
 187
 188 static struct lock_torture_ops spin_lock_ops = {
 189         .writelock      = torture_spin_lock_write_lock,
 190         .write_delay    = torture_spin_lock_write_delay,
 191         .task_boost     = torture_boost_dummy,
 192         .writeunlock    = torture_spin_lock_write_unlock,
 193         .readlock       = NULL,
 194         .read_delay     = NULL,
 195         .readunlock     = NULL,
 196         .name           = "spin_lock"
 197 };
 198
 199 static int torture_spin_lock_write_lock_irq(void)
 200 __acquires(torture_spinlock)
 201 {
 202         unsigned long flags;
 203
 204         spin_lock_irqsave(&torture_spinlock, flags);
 205         cxt.cur_ops->flags = flags;
 206         return 0;
 207 }
 208
 209 static void torture_lock_spin_write_unlock_irq(void)
 210 __releases(torture_spinlock)
 211 {
 212         spin_unlock_irqrestore(&torture_spinlock, cxt.cur_ops->flags);
 213 }
 214
 215 static struct lock_torture_ops spin_lock_irq_ops = {
 216         .writelock      = torture_spin_lock_write_lock_irq,
 217         .write_delay    = torture_spin_lock_write_delay,
 218         .task_boost     = torture_boost_dummy,
 219         .writeunlock    = torture_lock_spin_write_unlock_irq,
 220         .readlock       = NULL,
 221         .read_delay     = NULL,
 222         .readunlock     = NULL,
 223         .name           = "spin_lock_irq"
 224 };
 225
 226 static DEFINE_RWLOCK(torture_rwlock);
 227
 228 static int torture_rwlock_write_lock(void) __acquires(torture_rwlock)
 229 {
 230         write_lock(&torture_rwlock);
 231         return 0;
 232 }
 233
 234 static void torture_rwlock_write_delay(struct torture_random_state *trsp)
 235 {
 236         const unsigned long shortdelay_us = 2;
 237         const unsigned long longdelay_ms = 100;
 238
 239         /* We want a short delay mostly to emulate likely code, and
 240          * we want a long delay occasionally to force massive contention.
 241          */
 242         if (!(torture_random(trsp) %
 243               (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
 244                 mdelay(longdelay_ms);
 245         else
 246                 udelay(shortdelay_us);
 247 }
 248
 249 static void torture_rwlock_write_unlock(void) __releases(torture_rwlock)
 250 {
 251         write_unlock(&torture_rwlock);
 252 }
 253
 254 static int torture_rwlock_read_lock(void) __acquires(torture_rwlock)
 255 {
 256         read_lock(&torture_rwlock);
 257         return 0;
 258 }
 259
 260 static void torture_rwlock_read_delay(struct torture_random_state *trsp)
 261 {
 262         const unsigned long shortdelay_us = 10;
 263         const unsigned long longdelay_ms = 100;
 264
 265         /* We want a short delay mostly to emulate likely code, and
 266          * we want a long delay occasionally to force massive contention.
 267          */
 268         if (!(torture_random(trsp) %
 269               (cxt.nrealreaders_stress * 2000 * longdelay_ms)))
 270                 mdelay(longdelay_ms);
 271         else
 272                 udelay(shortdelay_us);
 273 }
 274
 275 static void torture_rwlock_read_unlock(void) __releases(torture_rwlock)
 276 {
 277         read_unlock(&torture_rwlock);
 278 }
 279
 280 static struct lock_torture_ops rw_lock_ops = {
 281         .writelock      = torture_rwlock_write_lock,
 282         .write_delay    = torture_rwlock_write_delay,
 283         .task_boost     = torture_boost_dummy,
 284         .writeunlock    = torture_rwlock_write_unlock,
 285         .readlock       = torture_rwlock_read_lock,
 286         .read_delay     = torture_rwlock_read_delay,
 287         .readunlock     = torture_rwlock_read_unlock,
 288         .name           = "rw_lock"
 289 };
 290
 291 static int torture_rwlock_write_lock_irq(void) __acquires(torture_rwlock)
 292 {
 293         unsigned long flags;
 294
 295         write_lock_irqsave(&torture_rwlock, flags);
 296         cxt.cur_ops->flags = flags;
 297         return 0;
 298 }
 299
 300 static void torture_rwlock_write_unlock_irq(void)
 301 __releases(torture_rwlock)
 302 {
 303         write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
 304 }
 305
 306 static int torture_rwlock_read_lock_irq(void) __acquires(torture_rwlock)
 307 {
 308         unsigned long flags;
 309
 310         read_lock_irqsave(&torture_rwlock, flags);
 311         cxt.cur_ops->flags = flags;
 312         return 0;
 313 }
 314
 315 static void torture_rwlock_read_unlock_irq(void)
 316 __releases(torture_rwlock)
 317 {
 318         read_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
 319 }
 320
 321 static struct lock_torture_ops rw_lock_irq_ops = {
 322         .writelock      = torture_rwlock_write_lock_irq,
 323         .write_delay    = torture_rwlock_write_delay,
 324         .task_boost     = torture_boost_dummy,
 325         .writeunlock    = torture_rwlock_write_unlock_irq,
 326         .readlock       = torture_rwlock_read_lock_irq,
 327         .read_delay     = torture_rwlock_read_delay,
 328         .readunlock     = torture_rwlock_read_unlock_irq,
 329         .name           = "rw_lock_irq"
 330 };
 331
 332 static DEFINE_MUTEX(torture_mutex);
 333
 334 static int torture_mutex_lock(void) __acquires(torture_mutex)
 335 {
 336         mutex_lock(&torture_mutex);
 337         return 0;
 338 }
 339
 340 static void torture_mutex_delay(struct torture_random_state *trsp)
 341 {
 342         const unsigned long longdelay_ms = 100;
 343
 344         /* We want a long delay occasionally to force massive contention.  */
 345         if (!(torture_random(trsp) %
 346               (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
 347                 mdelay(longdelay_ms * 5);
 348         else
 349                 mdelay(longdelay_ms / 5);
 350         if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
 351                 torture_preempt_schedule();  /* Allow test to be preempted. */
 352 }
 353
 354 static void torture_mutex_unlock(void) __releases(torture_mutex)
 355 {
 356         mutex_unlock(&torture_mutex);
 357 }
 358
 359 static struct lock_torture_ops mutex_lock_ops = {
 360         .writelock      = torture_mutex_lock,
 361         .write_delay    = torture_mutex_delay,
 362         .task_boost     = torture_boost_dummy,
 363         .writeunlock    = torture_mutex_unlock,
 364         .readlock       = NULL,
 365         .read_delay     = NULL,
 366         .readunlock     = NULL,
 367         .name           = "mutex_lock"
 368 };
 369
 370 #include <linux/ww_mutex.h>
 371 static DEFINE_WD_CLASS(torture_ww_class);
 372 static DEFINE_WW_MUTEX(torture_ww_mutex_0, &torture_ww_class);
 373 static DEFINE_WW_MUTEX(torture_ww_mutex_1, &torture_ww_class);
 374 static DEFINE_WW_MUTEX(torture_ww_mutex_2, &torture_ww_class);
 375
 376 static int torture_ww_mutex_lock(void)
 377 __acquires(torture_ww_mutex_0)
 378 __acquires(torture_ww_mutex_1)
 379 __acquires(torture_ww_mutex_2)
 380 {
 381         LIST_HEAD(list);
 382         struct reorder_lock {
 383                 struct list_head link;
 384                 struct ww_mutex *lock;
 385         } locks[3], *ll, *ln;
 386         struct ww_acquire_ctx ctx;
 387
 388         locks[0].lock = &torture_ww_mutex_0;
 389         list_add(&locks[0].link, &list);
 390
 391         locks[1].lock = &torture_ww_mutex_1;
 392         list_add(&locks[1].link, &list);
 393
 394         locks[2].lock = &torture_ww_mutex_2;
 395         list_add(&locks[2].link, &list);
 396
 397         ww_acquire_init(&ctx, &torture_ww_class);
 398
 399         list_for_each_entry(ll, &list, link) {
 400                 int err;
 401
 402                 err = ww_mutex_lock(ll->lock, &ctx);
 403                 if (!err)
 404                         continue;
 405
 406                 ln = ll;
 407                 list_for_each_entry_continue_reverse(ln, &list, link)
 408                         ww_mutex_unlock(ln->lock);
 409
 410                 if (err != -EDEADLK)
 411                         return err;
 412
 413                 ww_mutex_lock_slow(ll->lock, &ctx);
 414                 list_move(&ll->link, &list);
 415         }
 416
 417         ww_acquire_fini(&ctx);
 418         return 0;
 419 }
 420
 421 static void torture_ww_mutex_unlock(void)
 422 __releases(torture_ww_mutex_0)
 423 __releases(torture_ww_mutex_1)
 424 __releases(torture_ww_mutex_2)
 425 {
 426         ww_mutex_unlock(&torture_ww_mutex_0);
 427         ww_mutex_unlock(&torture_ww_mutex_1);
 428         ww_mutex_unlock(&torture_ww_mutex_2);
 429 }
 430
 431 static struct lock_torture_ops ww_mutex_lock_ops = {
 432         .writelock      = torture_ww_mutex_lock,
 433         .write_delay    = torture_mutex_delay,
 434         .task_boost     = torture_boost_dummy,
 435         .writeunlock    = torture_ww_mutex_unlock,
 436         .readlock       = NULL,
 437         .read_delay     = NULL,
 438         .readunlock     = NULL,
 439         .name           = "ww_mutex_lock"
 440 };
 441
 442 #ifdef CONFIG_RT_MUTEXES
 443 static DEFINE_RT_MUTEX(torture_rtmutex);
 444
 445 static int torture_rtmutex_lock(void) __acquires(torture_rtmutex)
 446 {
 447         rt_mutex_lock(&torture_rtmutex);
 448         return 0;
 449 }
 450
 451 static void torture_rtmutex_boost(struct torture_random_state *trsp)
 452 {
 453         int policy;
 454         struct sched_param param;
 455         const unsigned int factor = 50000; /* yes, quite arbitrary */
 456
 457         if (!rt_task(current)) {
 458                 /*
 459                  * Boost priority once every ~50k operations. When the
 460                  * task tries to take the lock, the rtmutex it will account
 461                  * for the new priority, and do any corresponding pi-dance.
 462                  */
 463                 if (trsp && !(torture_random(trsp) %
 464                               (cxt.nrealwriters_stress * factor))) {
 465                         policy = SCHED_FIFO;
 466                         param.sched_priority = MAX_RT_PRIO - 1;
 467                 } else /* common case, do nothing */
 468                         return;
 469         } else {
 470                 /*
 471                  * The task will remain boosted for another ~500k operations,
 472                  * then restored back to its original prio, and so forth.
 473                  *
 474                  * When @trsp is nil, we want to force-reset the task for
 475                  * stopping the kthread.
 476                  */
 477                 if (!trsp || !(torture_random(trsp) %
 478                                (cxt.nrealwriters_stress * factor * 2))) {
 479                         policy = SCHED_NORMAL;
 480                         param.sched_priority = 0;
 481                 } else /* common case, do nothing */
 482                         return;
 483         }
 484
 485         sched_setscheduler_nocheck(current, policy, &param);
 486 }
 487
 488 static void torture_rtmutex_delay(struct torture_random_state *trsp)
 489 {
 490         const unsigned long shortdelay_us = 2;
 491         const unsigned long longdelay_ms = 100;
 492
 493         /*
 494          * We want a short delay mostly to emulate likely code, and
 495          * we want a long delay occasionally to force massive contention.
 496          */
 497         if (!(torture_random(trsp) %
 498               (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
 499                 mdelay(longdelay_ms);
 500         if (!(torture_random(trsp) %
 501               (cxt.nrealwriters_stress * 2 * shortdelay_us)))
 502                 udelay(shortdelay_us);
 503         if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
 504                 torture_preempt_schedule();  /* Allow test to be preempted. */
 505 }
 506
 507 static void torture_rtmutex_unlock(void) __releases(torture_rtmutex)
 508 {
 509         rt_mutex_unlock(&torture_rtmutex);
 510 }
 511
 512 static struct lock_torture_ops rtmutex_lock_ops = {
 513         .writelock      = torture_rtmutex_lock,
 514         .write_delay    = torture_rtmutex_delay,
 515         .task_boost     = torture_rtmutex_boost,
 516         .writeunlock    = torture_rtmutex_unlock,
 517         .readlock       = NULL,
 518         .read_delay     = NULL,
 519         .readunlock     = NULL,
 520         .name           = "rtmutex_lock"
 521 };
 522 #endif
 523
 524 static DECLARE_RWSEM(torture_rwsem);
 525 static int torture_rwsem_down_write(void) __acquires(torture_rwsem)
 526 {
 527         down_write(&torture_rwsem);
 528         return 0;
 529 }
 530
 531 static void torture_rwsem_write_delay(struct torture_random_state *trsp)
 532 {
 533         const unsigned long longdelay_ms = 100;
 534
 535         /* We want a long delay occasionally to force massive contention.  */
 536         if (!(torture_random(trsp) %
 537               (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
 538                 mdelay(longdelay_ms * 10);
 539         else
 540                 mdelay(longdelay_ms / 10);
 541         if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
 542                 torture_preempt_schedule();  /* Allow test to be preempted. */
 543 }
 544
 545 static void torture_rwsem_up_write(void) __releases(torture_rwsem)
 546 {
 547         up_write(&torture_rwsem);
 548 }
 549
 550 static int torture_rwsem_down_read(void) __acquires(torture_rwsem)
 551 {
 552         down_read(&torture_rwsem);
 553         return 0;
 554 }
 555
 556 static void torture_rwsem_read_delay(struct torture_random_state *trsp)
 557 {
 558         const unsigned long longdelay_ms = 100;
 559
 560         /* We want a long delay occasionally to force massive contention.  */
 561         if (!(torture_random(trsp) %
 562               (cxt.nrealreaders_stress * 2000 * longdelay_ms)))
 563                 mdelay(longdelay_ms * 2);
 564         else
 565                 mdelay(longdelay_ms / 2);
 566         if (!(torture_random(trsp) % (cxt.nrealreaders_stress * 20000)))
 567                 torture_preempt_schedule();  /* Allow test to be preempted. */
 568 }
 569
 570 static void torture_rwsem_up_read(void) __releases(torture_rwsem)
 571 {
 572         up_read(&torture_rwsem);
 573 }
 574
 575 static struct lock_torture_ops rwsem_lock_ops = {
 576         .writelock      = torture_rwsem_down_write,
 577         .write_delay    = torture_rwsem_write_delay,
 578         .task_boost     = torture_boost_dummy,
 579         .writeunlock    = torture_rwsem_up_write,
 580         .readlock       = torture_rwsem_down_read,
 581         .read_delay     = torture_rwsem_read_delay,
 582         .readunlock     = torture_rwsem_up_read,
 583         .name           = "rwsem_lock"
 584 };
 585
 586 #include <linux/percpu-rwsem.h>
 587 static struct percpu_rw_semaphore pcpu_rwsem;
 588
 589 void torture_percpu_rwsem_init(void)
 590 {
 591         BUG_ON(percpu_init_rwsem(&pcpu_rwsem));
 592 }
 593
 594 static int torture_percpu_rwsem_down_write(void) __acquires(pcpu_rwsem)
 595 {
 596         percpu_down_write(&pcpu_rwsem);
 597         return 0;
 598 }
 599
 600 static void torture_percpu_rwsem_up_write(void) __releases(pcpu_rwsem)
 601 {
 602         percpu_up_write(&pcpu_rwsem);
 603 }
 604
 605 static int torture_percpu_rwsem_down_read(void) __acquires(pcpu_rwsem)
 606 {
 607         percpu_down_read(&pcpu_rwsem);
 608         return 0;
 609 }
 610
 611 static void torture_percpu_rwsem_up_read(void) __releases(pcpu_rwsem)
 612 {
 613         percpu_up_read(&pcpu_rwsem);
 614 }
 615
 616 static struct lock_torture_ops percpu_rwsem_lock_ops = {
 617         .init           = torture_percpu_rwsem_init,
 618         .writelock      = torture_percpu_rwsem_down_write,
 619         .write_delay    = torture_rwsem_write_delay,
 620         .task_boost     = torture_boost_dummy,
 621         .writeunlock    = torture_percpu_rwsem_up_write,
 622         .readlock       = torture_percpu_rwsem_down_read,
 623         .read_delay     = torture_rwsem_read_delay,
 624         .readunlock     = torture_percpu_rwsem_up_read,
 625         .name           = "percpu_rwsem_lock"
 626 };
 627
 628 /*
 629  * Lock torture writer kthread.  Repeatedly acquires and releases
 630  * the lock, checking for duplicate acquisitions.
 631  */
 632 static int lock_torture_writer(void *arg)
 633 {
 634         struct lock_stress_stats *lwsp = arg;
 635         static DEFINE_TORTURE_RANDOM(rand);
 636
 637         VERBOSE_TOROUT_STRING("lock_torture_writer task started");
 638         set_user_nice(current, MAX_NICE);
 639
 640         do {
 641                 if ((torture_random(&rand) & 0xfffff) == 0)
 642                         schedule_timeout_uninterruptible(1);
 643
 644                 cxt.cur_ops->task_boost(&rand);
 645                 cxt.cur_ops->writelock();
 646                 if (WARN_ON_ONCE(lock_is_write_held))
 647                         lwsp->n_lock_fail++;
 648                 lock_is_write_held = 1;
 649                 if (WARN_ON_ONCE(lock_is_read_held))
 650                         lwsp->n_lock_fail++; /* rare, but... */
 651
 652                 lwsp->n_lock_acquired++;
 653                 cxt.cur_ops->write_delay(&rand);
 654                 lock_is_write_held = 0;
 655                 cxt.cur_ops->writeunlock();
 656
 657                 stutter_wait("lock_torture_writer");
 658         } while (!torture_must_stop());
 659
 660         cxt.cur_ops->task_boost(NULL); /* reset prio */
 661         torture_kthread_stopping("lock_torture_writer");
 662         return 0;
 663 }
 664
 665 /*
 666  * Lock torture reader kthread.  Repeatedly acquires and releases
 667  * the reader lock.
 668  */
 669 static int lock_torture_reader(void *arg)
 670 {
 671         struct lock_stress_stats *lrsp = arg;
 672         static DEFINE_TORTURE_RANDOM(rand);
 673
 674         VERBOSE_TOROUT_STRING("lock_torture_reader task started");
 675         set_user_nice(current, MAX_NICE);
 676
 677         do {
 678                 if ((torture_random(&rand) & 0xfffff) == 0)
 679                         schedule_timeout_uninterruptible(1);
 680
 681                 cxt.cur_ops->readlock();
 682                 lock_is_read_held = 1;
 683                 if (WARN_ON_ONCE(lock_is_write_held))
 684                         lrsp->n_lock_fail++; /* rare, but... */
 685
 686                 lrsp->n_lock_acquired++;
 687                 cxt.cur_ops->read_delay(&rand);
 688                 lock_is_read_held = 0;
 689                 cxt.cur_ops->readunlock();
 690
 691                 stutter_wait("lock_torture_reader");
 692         } while (!torture_must_stop());
 693         torture_kthread_stopping("lock_torture_reader");
 694         return 0;
 695 }
 696
 697 /*
 698  * Create an lock-torture-statistics message in the specified buffer.
 699  */
 700 static void __torture_print_stats(char *page,
 701                                   struct lock_stress_stats *statp, bool write)
 702 {
 703         bool fail = 0;
 704         int i, n_stress;
 705         long max = 0, min = statp ? statp[0].n_lock_acquired : 0;
 706         long long sum = 0;
 707
 708         n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress;
 709         for (i = 0; i < n_stress; i++) {
 710                 if (statp[i].n_lock_fail)
 711                         fail = true;
 712                 sum += statp[i].n_lock_acquired;
 713                 if (max < statp[i].n_lock_fail)
 714                         max = statp[i].n_lock_fail;
 715                 if (min > statp[i].n_lock_fail)
 716                         min = statp[i].n_lock_fail;
 717         }
 718         page += sprintf(page,
 719                         "%s:  Total: %lld  Max/Min: %ld/%ld %s  Fail: %d %s\n",
 720                         write ? "Writes" : "Reads ",
 721                         sum, max, min, max / 2 > min ? "???" : "",
 722                         fail, fail ? "!!!" : "");
 723         if (fail)
 724                 atomic_inc(&cxt.n_lock_torture_errors);
 725 }
 726
 727 /*
 728  * Print torture statistics.  Caller must ensure that there is only one
 729  * call to this function at a given time!!!  This is normally accomplished
 730  * by relying on the module system to only have one copy of the module
 731  * loaded, and then by giving the lock_torture_stats kthread full control
 732  * (or the init/cleanup functions when lock_torture_stats thread is not
 733  * running).
 734  */
 735 static void lock_torture_stats_print(void)
 736 {
 737         int size = cxt.nrealwriters_stress * 200 + 8192;
 738         char *buf;
 739
 740         if (cxt.cur_ops->readlock)
 741                 size += cxt.nrealreaders_stress * 200 + 8192;
 742
 743         buf = kmalloc(size, GFP_KERNEL);
 744         if (!buf) {
 745                 pr_err("lock_torture_stats_print: Out of memory, need: %d",
 746                        size);
 747                 return;
 748         }
 749
 750         __torture_print_stats(buf, cxt.lwsa, true);
 751         pr_alert("%s", buf);
 752         kfree(buf);
 753
 754         if (cxt.cur_ops->readlock) {
 755                 buf = kmalloc(size, GFP_KERNEL);
 756                 if (!buf) {
 757                         pr_err("lock_torture_stats_print: Out of memory, need: %d",
 758                                size);
 759                         return;
 760                 }
 761
 762                 __torture_print_stats(buf, cxt.lrsa, false);
 763                 pr_alert("%s", buf);
 764                 kfree(buf);
 765         }
 766 }
 767
 768 /*
 769  * Periodically prints torture statistics, if periodic statistics printing
 770  * was specified via the stat_interval module parameter.
 771  *
 772  * No need to worry about fullstop here, since this one doesn't reference
 773  * volatile state or register callbacks.
 774  */
 775 static int lock_torture_stats(void *arg)
 776 {
 777         VERBOSE_TOROUT_STRING("lock_torture_stats task started");
 778         do {
 779                 schedule_timeout_interruptible(stat_interval * HZ);
 780                 lock_torture_stats_print();
 781                 torture_shutdown_absorb("lock_torture_stats");
 782         } while (!torture_must_stop());
 783         torture_kthread_stopping("lock_torture_stats");
 784         return 0;
 785 }
 786
 787 static inline void
 788 lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
 789                                 const char *tag)
 790 {
 791         pr_alert("%s" TORTURE_FLAG
 792                  "--- %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",
 793                  torture_type, tag, cxt.debug_lock ? " [debug]": "",
 794                  cxt.nrealwriters_stress, cxt.nrealreaders_stress, stat_interval,
 795                  verbose, shuffle_interval, stutter, shutdown_secs,
 796                  onoff_interval, onoff_holdoff);
 797 }
 798
 799 static void lock_torture_cleanup(void)
 800 {
 801         int i;
 802
 803         if (torture_cleanup_begin())
 804                 return;
 805
 806         /*
 807          * Indicates early cleanup, meaning that the test has not run,
 808          * such as when passing bogus args when loading the module. As
 809          * such, only perform the underlying torture-specific cleanups,
 810          * and avoid anything related to locktorture.
 811          */
 812         if (!cxt.lwsa && !cxt.lrsa)
 813                 goto end;
 814
 815         if (writer_tasks) {
 816                 for (i = 0; i < cxt.nrealwriters_stress; i++)
 817                         torture_stop_kthread(lock_torture_writer,
 818                                              writer_tasks[i]);
 819                 kfree(writer_tasks);
 820                 writer_tasks = NULL;
 821         }
 822
 823         if (reader_tasks) {
 824                 for (i = 0; i < cxt.nrealreaders_stress; i++)
 825                         torture_stop_kthread(lock_torture_reader,
 826                                              reader_tasks[i]);
 827                 kfree(reader_tasks);
 828                 reader_tasks = NULL;
 829         }
 830
 831         torture_stop_kthread(lock_torture_stats, stats_task);
 832         lock_torture_stats_print();  /* -After- the stats thread is stopped! */
 833
 834         if (atomic_read(&cxt.n_lock_torture_errors))
 835                 lock_torture_print_module_parms(cxt.cur_ops,
 836                                                 "End of test: FAILURE");
 837         else if (torture_onoff_failures())
 838                 lock_torture_print_module_parms(cxt.cur_ops,
 839                                                 "End of test: LOCK_HOTPLUG");
 840         else
 841                 lock_torture_print_module_parms(cxt.cur_ops,
 842                                                 "End of test: SUCCESS");
 843
 844         kfree(cxt.lwsa);
 845         kfree(cxt.lrsa);
 846
 847 end:
 848         torture_cleanup_end();
 849 }
 850
 851 static int __init lock_torture_init(void)
 852 {
 853         int i, j;
 854         int firsterr = 0;
 855         static struct lock_torture_ops *torture_ops[] = {
 856                 &lock_busted_ops,
 857                 &spin_lock_ops, &spin_lock_irq_ops,
 858                 &rw_lock_ops, &rw_lock_irq_ops,
 859                 &mutex_lock_ops,
 860                 &ww_mutex_lock_ops,
 861 #ifdef CONFIG_RT_MUTEXES
 862                 &rtmutex_lock_ops,
 863 #endif
 864                 &rwsem_lock_ops,
 865                 &percpu_rwsem_lock_ops,
 866         };
 867
 868         if (!torture_init_begin(torture_type, verbose))
 869                 return -EBUSY;
 870
 871         /* Process args and tell the world that the torturer is on the job. */
 872         for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
 873                 cxt.cur_ops = torture_ops[i];
 874                 if (strcmp(torture_type, cxt.cur_ops->name) == 0)
 875                         break;
 876         }
 877         if (i == ARRAY_SIZE(torture_ops)) {
 878                 pr_alert("lock-torture: invalid torture type: \"%s\"\n",
 879                          torture_type);
 880                 pr_alert("lock-torture types:");
 881                 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
 882                         pr_alert(" %s", torture_ops[i]->name);
 883                 pr_alert("\n");
 884                 firsterr = -EINVAL;
 885                 goto unwind;
 886         }
 887
 888         if (nwriters_stress == 0 && nreaders_stress == 0) {
 889                 pr_alert("lock-torture: must run at least one locking thread\n");
 890                 firsterr = -EINVAL;
 891                 goto unwind;
 892         }
 893
 894         if (cxt.cur_ops->init)
 895                 cxt.cur_ops->init();
 896
 897         if (nwriters_stress >= 0)
 898                 cxt.nrealwriters_stress = nwriters_stress;
 899         else
 900                 cxt.nrealwriters_stress = 2 * num_online_cpus();
 901
 902 #ifdef CONFIG_DEBUG_MUTEXES
 903         if (strncmp(torture_type, "mutex", 5) == 0)
 904                 cxt.debug_lock = true;
 905 #endif
 906 #ifdef CONFIG_DEBUG_RT_MUTEXES
 907         if (strncmp(torture_type, "rtmutex", 7) == 0)
 908                 cxt.debug_lock = true;
 909 #endif
 910 #ifdef CONFIG_DEBUG_SPINLOCK
 911         if ((strncmp(torture_type, "spin", 4) == 0) ||
 912             (strncmp(torture_type, "rw_lock", 7) == 0))
 913                 cxt.debug_lock = true;
 914 #endif
 915
 916         /* Initialize the statistics so that each run gets its own numbers. */
 917         if (nwriters_stress) {
 918                 lock_is_write_held = 0;
 919                 cxt.lwsa = kmalloc_array(cxt.nrealwriters_stress,
 920                                          sizeof(*cxt.lwsa),
 921                                          GFP_KERNEL);
 922                 if (cxt.lwsa == NULL) {
 923                         VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory");
 924                         firsterr = -ENOMEM;
 925                         goto unwind;
 926                 }
 927
 928                 for (i = 0; i < cxt.nrealwriters_stress; i++) {
 929                         cxt.lwsa[i].n_lock_fail = 0;
 930                         cxt.lwsa[i].n_lock_acquired = 0;
 931                 }
 932         }
 933
 934         if (cxt.cur_ops->readlock) {
 935                 if (nreaders_stress >= 0)
 936                         cxt.nrealreaders_stress = nreaders_stress;
 937                 else {
 938                         /*
 939                          * By default distribute evenly the number of
 940                          * readers and writers. We still run the same number
 941                          * of threads as the writer-only locks default.
 942                          */
 943                         if (nwriters_stress < 0) /* user doesn't care */
 944                                 cxt.nrealwriters_stress = num_online_cpus();
 945                         cxt.nrealreaders_stress = cxt.nrealwriters_stress;
 946                 }
 947
 948                 if (nreaders_stress) {
 949                         lock_is_read_held = 0;
 950                         cxt.lrsa = kmalloc_array(cxt.nrealreaders_stress,
 951                                                  sizeof(*cxt.lrsa),
 952                                                  GFP_KERNEL);
 953                         if (cxt.lrsa == NULL) {
 954                                 VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory");
 955                                 firsterr = -ENOMEM;
 956                                 kfree(cxt.lwsa);
 957                                 cxt.lwsa = NULL;
 958                                 goto unwind;
 959                         }
 960
 961                         for (i = 0; i < cxt.nrealreaders_stress; i++) {
 962                                 cxt.lrsa[i].n_lock_fail = 0;
 963                                 cxt.lrsa[i].n_lock_acquired = 0;
 964                         }
 965                 }
 966         }
 967
 968         lock_torture_print_module_parms(cxt.cur_ops, "Start of test");
 969
 970         /* Prepare torture context. */
 971         if (onoff_interval > 0) {
 972                 firsterr = torture_onoff_init(onoff_holdoff * HZ,
 973                                               onoff_interval * HZ);
 974                 if (firsterr)
 975                         goto unwind;
 976         }
 977         if (shuffle_interval > 0) {
 978                 firsterr = torture_shuffle_init(shuffle_interval);
 979                 if (firsterr)
 980                         goto unwind;
 981         }
 982         if (shutdown_secs > 0) {
 983                 firsterr = torture_shutdown_init(shutdown_secs,
 984                                                  lock_torture_cleanup);
 985                 if (firsterr)
 986                         goto unwind;
 987         }
 988         if (stutter > 0) {
 989                 firsterr = torture_stutter_init(stutter);
 990                 if (firsterr)
 991                         goto unwind;
 992         }
 993
 994         if (nwriters_stress) {
 995                 writer_tasks = kcalloc(cxt.nrealwriters_stress,
 996                                        sizeof(writer_tasks[0]),
 997                                        GFP_KERNEL);
 998                 if (writer_tasks == NULL) {
 999                         VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory");
1000                         firsterr = -ENOMEM;
1001                         goto unwind;
1002                 }
1003         }
1004
1005         if (cxt.cur_ops->readlock) {
1006                 reader_tasks = kcalloc(cxt.nrealreaders_stress,
1007                                        sizeof(reader_tasks[0]),
1008                                        GFP_KERNEL);
1009                 if (reader_tasks == NULL) {
1010                         VERBOSE_TOROUT_ERRSTRING("reader_tasks: Out of memory");
1011                         kfree(writer_tasks);
1012                         writer_tasks = NULL;
1013                         firsterr = -ENOMEM;
1014                         goto unwind;
1015                 }
1016         }
1017
1018         /*
1019          * Create the kthreads and start torturing (oh, those poor little locks).
1020          *
1021          * TODO: Note that we interleave writers with readers, giving writers a
1022          * slight advantage, by creating its kthread first. This can be modified
1023          * for very specific needs, or even let the user choose the policy, if
1024          * ever wanted.
1025          */
1026         for (i = 0, j = 0; i < cxt.nrealwriters_stress ||
1027                     j < cxt.nrealreaders_stress; i++, j++) {
1028                 if (i >= cxt.nrealwriters_stress)
1029                         goto create_reader;
1030
1031                 /* Create writer. */
1032                 firsterr = torture_create_kthread(lock_torture_writer, &cxt.lwsa[i],
1033                                                   writer_tasks[i]);
1034                 if (firsterr)
1035                         goto unwind;
1036
1037         create_reader:
1038                 if (cxt.cur_ops->readlock == NULL || (j >= cxt.nrealreaders_stress))
1039                         continue;
1040                 /* Create reader. */
1041                 firsterr = torture_create_kthread(lock_torture_reader, &cxt.lrsa[j],
1042                                                   reader_tasks[j]);
1043                 if (firsterr)
1044                         goto unwind;
1045         }
1046         if (stat_interval > 0) {
1047                 firsterr = torture_create_kthread(lock_torture_stats, NULL,
1048                                                   stats_task);
1049                 if (firsterr)
1050                         goto unwind;
1051         }
1052         torture_init_end();
1053         return 0;
1054
1055 unwind:
1056         torture_init_end();
1057         lock_torture_cleanup();
1058         return firsterr;
1059 }
1060
1061 module_init(lock_torture_init);
1062 module_exit(lock_torture_cleanup);