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