1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Module-based torture test facility for locking 4 * 5 * Copyright (C) IBM Corporation, 2014 6 * 7 * Authors: Paul E. McKenney <paulmck@linux.ibm.com> 8 * Davidlohr Bueso <dave@stgolabs.net> 9 * Based on kernel/rcu/torture.c. 10 */ 11 12 #define pr_fmt(fmt) fmt 13 14 #include <linux/kernel.h> 15 #include <linux/module.h> 16 #include <linux/kthread.h> 17 #include <linux/sched/rt.h> 18 #include <linux/spinlock.h> 19 #include <linux/mutex.h> 20 #include <linux/rwsem.h> 21 #include <linux/smp.h> 22 #include <linux/interrupt.h> 23 #include <linux/sched.h> 24 #include <uapi/linux/sched/types.h> 25 #include <linux/rtmutex.h> 26 #include <linux/atomic.h> 27 #include <linux/moduleparam.h> 28 #include <linux/delay.h> 29 #include <linux/slab.h> 30 #include <linux/torture.h> 31 #include <linux/reboot.h> 32 33 MODULE_LICENSE("GPL"); 34 MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>"); 35 36 torture_param(int, acq_writer_lim, 0, "Write_acquisition time limit (jiffies)."); 37 torture_param(int, call_rcu_chains, 0, "Self-propagate call_rcu() chains during test (0=disable)."); 38 torture_param(int, long_hold, 100, "Do occasional long hold of lock (ms), 0=disable"); 39 torture_param(int, nested_locks, 0, "Number of nested locks (max = 8)"); 40 torture_param(int, nreaders_stress, -1, "Number of read-locking stress-test threads"); 41 torture_param(int, nwriters_stress, -1, "Number of write-locking stress-test threads"); 42 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)"); 43 torture_param(int, onoff_interval, 0, "Time between CPU hotplugs (s), 0=disable"); 44 torture_param(int, rt_boost, 2, 45 "Do periodic rt-boost. 0=Disable, 1=Only for rt_mutex, 2=For all lock types."); 46 torture_param(int, rt_boost_factor, 50, "A factor determining how often rt-boost happens."); 47 torture_param(int, shuffle_interval, 3, "Number of jiffies between shuffles, 0=disable"); 48 torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable."); 49 torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s"); 50 torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable"); 51 torture_param(int, verbose, 1, "Enable verbose debugging printk()s"); 52 torture_param(int, writer_fifo, 0, "Run writers at sched_set_fifo() priority"); 53 /* Going much higher trips "BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!" errors */ 54 #define MAX_NESTED_LOCKS 8 55 56 static char *torture_type = IS_ENABLED(CONFIG_PREEMPT_RT) ? "raw_spin_lock" : "spin_lock"; 57 module_param(torture_type, charp, 0444); 58 MODULE_PARM_DESC(torture_type, 59 "Type of lock to torture (spin_lock, spin_lock_irq, mutex_lock, ...)"); 60 61 static cpumask_var_t bind_readers; // Bind the readers to the specified set of CPUs. 62 static cpumask_var_t bind_writers; // Bind the writers to the specified set of CPUs. 63 64 // Parse a cpumask kernel parameter. If there are more users later on, 65 // this might need to got to a more central location. 66 static int param_set_cpumask(const char *val, const struct kernel_param *kp) 67 { 68 cpumask_var_t *cm_bind = kp->arg; 69 int ret; 70 char *s; 71 72 if (!alloc_cpumask_var(cm_bind, GFP_KERNEL)) { 73 s = "Out of memory"; 74 ret = -ENOMEM; 75 goto out_err; 76 } 77 ret = cpulist_parse(val, *cm_bind); 78 if (!ret) 79 return ret; 80 s = "Bad CPU range"; 81 out_err: 82 pr_warn("%s: %s, all CPUs set\n", kp->name, s); 83 cpumask_setall(*cm_bind); 84 return ret; 85 } 86 87 // Output a cpumask kernel parameter. 88 static int param_get_cpumask(char *buffer, const struct kernel_param *kp) 89 { 90 cpumask_var_t *cm_bind = kp->arg; 91 92 return sprintf(buffer, "%*pbl", cpumask_pr_args(*cm_bind)); 93 } 94 95 static bool cpumask_nonempty(cpumask_var_t mask) 96 { 97 return cpumask_available(mask) && !cpumask_empty(mask); 98 } 99 100 static const struct kernel_param_ops lt_bind_ops = { 101 .set = param_set_cpumask, 102 .get = param_get_cpumask, 103 }; 104 105 module_param_cb(bind_readers, <_bind_ops, &bind_readers, 0644); 106 module_param_cb(bind_writers, <_bind_ops, &bind_writers, 0644); 107 108 long torture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask); 109 110 static struct task_struct *stats_task; 111 static struct task_struct **writer_tasks; 112 static struct task_struct **reader_tasks; 113 114 static bool lock_is_write_held; 115 static atomic_t lock_is_read_held; 116 static unsigned long last_lock_release; 117 118 struct lock_stress_stats { 119 long n_lock_fail; 120 long n_lock_acquired; 121 }; 122 123 struct call_rcu_chain { 124 struct rcu_head crc_rh; 125 bool crc_stop; 126 }; 127 struct call_rcu_chain *call_rcu_chain; 128 129 /* Forward reference. */ 130 static void lock_torture_cleanup(void); 131 132 /* 133 * Operations vector for selecting different types of tests. 134 */ 135 struct lock_torture_ops { 136 void (*init)(void); 137 void (*exit)(void); 138 int (*nested_lock)(int tid, u32 lockset); 139 int (*writelock)(int tid); 140 void (*write_delay)(struct torture_random_state *trsp); 141 void (*task_boost)(struct torture_random_state *trsp); 142 void (*writeunlock)(int tid); 143 void (*nested_unlock)(int tid, u32 lockset); 144 int (*readlock)(int tid); 145 void (*read_delay)(struct torture_random_state *trsp); 146 void (*readunlock)(int tid); 147 148 unsigned long flags; /* for irq spinlocks */ 149 const char *name; 150 }; 151 152 struct lock_torture_cxt { 153 int nrealwriters_stress; 154 int nrealreaders_stress; 155 bool debug_lock; 156 bool init_called; 157 atomic_t n_lock_torture_errors; 158 struct lock_torture_ops *cur_ops; 159 struct lock_stress_stats *lwsa; /* writer statistics */ 160 struct lock_stress_stats *lrsa; /* reader statistics */ 161 }; 162 static struct lock_torture_cxt cxt = { 0, 0, false, false, 163 ATOMIC_INIT(0), 164 NULL, NULL}; 165 /* 166 * Definitions for lock torture testing. 167 */ 168 169 static int torture_lock_busted_write_lock(int tid __maybe_unused) 170 { 171 return 0; /* BUGGY, do not use in real life!!! */ 172 } 173 174 static void torture_lock_busted_write_delay(struct torture_random_state *trsp) 175 { 176 /* We want a long delay occasionally to force massive contention. */ 177 if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold))) 178 mdelay(long_hold); 179 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000))) 180 torture_preempt_schedule(); /* Allow test to be preempted. */ 181 } 182 183 static void torture_lock_busted_write_unlock(int tid __maybe_unused) 184 { 185 /* BUGGY, do not use in real life!!! */ 186 } 187 188 static void __torture_rt_boost(struct torture_random_state *trsp) 189 { 190 const unsigned int factor = rt_boost_factor; 191 192 if (!rt_task(current)) { 193 /* 194 * Boost priority once every rt_boost_factor operations. When 195 * the task tries to take the lock, the rtmutex it will account 196 * for the new priority, and do any corresponding pi-dance. 197 */ 198 if (trsp && !(torture_random(trsp) % 199 (cxt.nrealwriters_stress * factor))) { 200 sched_set_fifo(current); 201 } else /* common case, do nothing */ 202 return; 203 } else { 204 /* 205 * The task will remain boosted for another 10 * rt_boost_factor 206 * operations, then restored back to its original prio, and so 207 * forth. 208 * 209 * When @trsp is nil, we want to force-reset the task for 210 * stopping the kthread. 211 */ 212 if (!trsp || !(torture_random(trsp) % 213 (cxt.nrealwriters_stress * factor * 2))) { 214 sched_set_normal(current, 0); 215 } else /* common case, do nothing */ 216 return; 217 } 218 } 219 220 static void torture_rt_boost(struct torture_random_state *trsp) 221 { 222 if (rt_boost != 2) 223 return; 224 225 __torture_rt_boost(trsp); 226 } 227 228 static struct lock_torture_ops lock_busted_ops = { 229 .writelock = torture_lock_busted_write_lock, 230 .write_delay = torture_lock_busted_write_delay, 231 .task_boost = torture_rt_boost, 232 .writeunlock = torture_lock_busted_write_unlock, 233 .readlock = NULL, 234 .read_delay = NULL, 235 .readunlock = NULL, 236 .name = "lock_busted" 237 }; 238 239 static DEFINE_SPINLOCK(torture_spinlock); 240 241 static int torture_spin_lock_write_lock(int tid __maybe_unused) 242 __acquires(torture_spinlock) 243 { 244 spin_lock(&torture_spinlock); 245 return 0; 246 } 247 248 static void torture_spin_lock_write_delay(struct torture_random_state *trsp) 249 { 250 const unsigned long shortdelay_us = 2; 251 unsigned long j; 252 253 /* We want a short delay mostly to emulate likely code, and 254 * we want a long delay occasionally to force massive contention. 255 */ 256 if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold))) { 257 j = jiffies; 258 mdelay(long_hold); 259 pr_alert("%s: delay = %lu jiffies.\n", __func__, jiffies - j); 260 } 261 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 200 * shortdelay_us))) 262 udelay(shortdelay_us); 263 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000))) 264 torture_preempt_schedule(); /* Allow test to be preempted. */ 265 } 266 267 static void torture_spin_lock_write_unlock(int tid __maybe_unused) 268 __releases(torture_spinlock) 269 { 270 spin_unlock(&torture_spinlock); 271 } 272 273 static struct lock_torture_ops spin_lock_ops = { 274 .writelock = torture_spin_lock_write_lock, 275 .write_delay = torture_spin_lock_write_delay, 276 .task_boost = torture_rt_boost, 277 .writeunlock = torture_spin_lock_write_unlock, 278 .readlock = NULL, 279 .read_delay = NULL, 280 .readunlock = NULL, 281 .name = "spin_lock" 282 }; 283 284 static int torture_spin_lock_write_lock_irq(int tid __maybe_unused) 285 __acquires(torture_spinlock) 286 { 287 unsigned long flags; 288 289 spin_lock_irqsave(&torture_spinlock, flags); 290 cxt.cur_ops->flags = flags; 291 return 0; 292 } 293 294 static void torture_lock_spin_write_unlock_irq(int tid __maybe_unused) 295 __releases(torture_spinlock) 296 { 297 spin_unlock_irqrestore(&torture_spinlock, cxt.cur_ops->flags); 298 } 299 300 static struct lock_torture_ops spin_lock_irq_ops = { 301 .writelock = torture_spin_lock_write_lock_irq, 302 .write_delay = torture_spin_lock_write_delay, 303 .task_boost = torture_rt_boost, 304 .writeunlock = torture_lock_spin_write_unlock_irq, 305 .readlock = NULL, 306 .read_delay = NULL, 307 .readunlock = NULL, 308 .name = "spin_lock_irq" 309 }; 310 311 static DEFINE_RAW_SPINLOCK(torture_raw_spinlock); 312 313 static int torture_raw_spin_lock_write_lock(int tid __maybe_unused) 314 __acquires(torture_raw_spinlock) 315 { 316 raw_spin_lock(&torture_raw_spinlock); 317 return 0; 318 } 319 320 static void torture_raw_spin_lock_write_unlock(int tid __maybe_unused) 321 __releases(torture_raw_spinlock) 322 { 323 raw_spin_unlock(&torture_raw_spinlock); 324 } 325 326 static struct lock_torture_ops raw_spin_lock_ops = { 327 .writelock = torture_raw_spin_lock_write_lock, 328 .write_delay = torture_spin_lock_write_delay, 329 .task_boost = torture_rt_boost, 330 .writeunlock = torture_raw_spin_lock_write_unlock, 331 .readlock = NULL, 332 .read_delay = NULL, 333 .readunlock = NULL, 334 .name = "raw_spin_lock" 335 }; 336 337 static int torture_raw_spin_lock_write_lock_irq(int tid __maybe_unused) 338 __acquires(torture_raw_spinlock) 339 { 340 unsigned long flags; 341 342 raw_spin_lock_irqsave(&torture_raw_spinlock, flags); 343 cxt.cur_ops->flags = flags; 344 return 0; 345 } 346 347 static void torture_raw_spin_lock_write_unlock_irq(int tid __maybe_unused) 348 __releases(torture_raw_spinlock) 349 { 350 raw_spin_unlock_irqrestore(&torture_raw_spinlock, cxt.cur_ops->flags); 351 } 352 353 static struct lock_torture_ops raw_spin_lock_irq_ops = { 354 .writelock = torture_raw_spin_lock_write_lock_irq, 355 .write_delay = torture_spin_lock_write_delay, 356 .task_boost = torture_rt_boost, 357 .writeunlock = torture_raw_spin_lock_write_unlock_irq, 358 .readlock = NULL, 359 .read_delay = NULL, 360 .readunlock = NULL, 361 .name = "raw_spin_lock_irq" 362 }; 363 364 static DEFINE_RWLOCK(torture_rwlock); 365 366 static int torture_rwlock_write_lock(int tid __maybe_unused) 367 __acquires(torture_rwlock) 368 { 369 write_lock(&torture_rwlock); 370 return 0; 371 } 372 373 static void torture_rwlock_write_delay(struct torture_random_state *trsp) 374 { 375 const unsigned long shortdelay_us = 2; 376 377 /* We want a short delay mostly to emulate likely code, and 378 * we want a long delay occasionally to force massive contention. 379 */ 380 if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold))) 381 mdelay(long_hold); 382 else 383 udelay(shortdelay_us); 384 } 385 386 static void torture_rwlock_write_unlock(int tid __maybe_unused) 387 __releases(torture_rwlock) 388 { 389 write_unlock(&torture_rwlock); 390 } 391 392 static int torture_rwlock_read_lock(int tid __maybe_unused) 393 __acquires(torture_rwlock) 394 { 395 read_lock(&torture_rwlock); 396 return 0; 397 } 398 399 static void torture_rwlock_read_delay(struct torture_random_state *trsp) 400 { 401 const unsigned long shortdelay_us = 10; 402 403 /* We want a short delay mostly to emulate likely code, and 404 * we want a long delay occasionally to force massive contention. 405 */ 406 if (long_hold && !(torture_random(trsp) % (cxt.nrealreaders_stress * 2000 * long_hold))) 407 mdelay(long_hold); 408 else 409 udelay(shortdelay_us); 410 } 411 412 static void torture_rwlock_read_unlock(int tid __maybe_unused) 413 __releases(torture_rwlock) 414 { 415 read_unlock(&torture_rwlock); 416 } 417 418 static struct lock_torture_ops rw_lock_ops = { 419 .writelock = torture_rwlock_write_lock, 420 .write_delay = torture_rwlock_write_delay, 421 .task_boost = torture_rt_boost, 422 .writeunlock = torture_rwlock_write_unlock, 423 .readlock = torture_rwlock_read_lock, 424 .read_delay = torture_rwlock_read_delay, 425 .readunlock = torture_rwlock_read_unlock, 426 .name = "rw_lock" 427 }; 428 429 static int torture_rwlock_write_lock_irq(int tid __maybe_unused) 430 __acquires(torture_rwlock) 431 { 432 unsigned long flags; 433 434 write_lock_irqsave(&torture_rwlock, flags); 435 cxt.cur_ops->flags = flags; 436 return 0; 437 } 438 439 static void torture_rwlock_write_unlock_irq(int tid __maybe_unused) 440 __releases(torture_rwlock) 441 { 442 write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags); 443 } 444 445 static int torture_rwlock_read_lock_irq(int tid __maybe_unused) 446 __acquires(torture_rwlock) 447 { 448 unsigned long flags; 449 450 read_lock_irqsave(&torture_rwlock, flags); 451 cxt.cur_ops->flags = flags; 452 return 0; 453 } 454 455 static void torture_rwlock_read_unlock_irq(int tid __maybe_unused) 456 __releases(torture_rwlock) 457 { 458 read_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags); 459 } 460 461 static struct lock_torture_ops rw_lock_irq_ops = { 462 .writelock = torture_rwlock_write_lock_irq, 463 .write_delay = torture_rwlock_write_delay, 464 .task_boost = torture_rt_boost, 465 .writeunlock = torture_rwlock_write_unlock_irq, 466 .readlock = torture_rwlock_read_lock_irq, 467 .read_delay = torture_rwlock_read_delay, 468 .readunlock = torture_rwlock_read_unlock_irq, 469 .name = "rw_lock_irq" 470 }; 471 472 static DEFINE_MUTEX(torture_mutex); 473 static struct mutex torture_nested_mutexes[MAX_NESTED_LOCKS]; 474 static struct lock_class_key nested_mutex_keys[MAX_NESTED_LOCKS]; 475 476 static void torture_mutex_init(void) 477 { 478 int i; 479 480 for (i = 0; i < MAX_NESTED_LOCKS; i++) 481 __mutex_init(&torture_nested_mutexes[i], __func__, 482 &nested_mutex_keys[i]); 483 } 484 485 static int torture_mutex_nested_lock(int tid __maybe_unused, 486 u32 lockset) 487 { 488 int i; 489 490 for (i = 0; i < nested_locks; i++) 491 if (lockset & (1 << i)) 492 mutex_lock(&torture_nested_mutexes[i]); 493 return 0; 494 } 495 496 static int torture_mutex_lock(int tid __maybe_unused) 497 __acquires(torture_mutex) 498 { 499 mutex_lock(&torture_mutex); 500 return 0; 501 } 502 503 static void torture_mutex_delay(struct torture_random_state *trsp) 504 { 505 /* We want a long delay occasionally to force massive contention. */ 506 if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold))) 507 mdelay(long_hold * 5); 508 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000))) 509 torture_preempt_schedule(); /* Allow test to be preempted. */ 510 } 511 512 static void torture_mutex_unlock(int tid __maybe_unused) 513 __releases(torture_mutex) 514 { 515 mutex_unlock(&torture_mutex); 516 } 517 518 static void torture_mutex_nested_unlock(int tid __maybe_unused, 519 u32 lockset) 520 { 521 int i; 522 523 for (i = nested_locks - 1; i >= 0; i--) 524 if (lockset & (1 << i)) 525 mutex_unlock(&torture_nested_mutexes[i]); 526 } 527 528 static struct lock_torture_ops mutex_lock_ops = { 529 .init = torture_mutex_init, 530 .nested_lock = torture_mutex_nested_lock, 531 .writelock = torture_mutex_lock, 532 .write_delay = torture_mutex_delay, 533 .task_boost = torture_rt_boost, 534 .writeunlock = torture_mutex_unlock, 535 .nested_unlock = torture_mutex_nested_unlock, 536 .readlock = NULL, 537 .read_delay = NULL, 538 .readunlock = NULL, 539 .name = "mutex_lock" 540 }; 541 542 #include <linux/ww_mutex.h> 543 /* 544 * The torture ww_mutexes should belong to the same lock class as 545 * torture_ww_class to avoid lockdep problem. The ww_mutex_init() 546 * function is called for initialization to ensure that. 547 */ 548 static DEFINE_WD_CLASS(torture_ww_class); 549 static struct ww_mutex torture_ww_mutex_0, torture_ww_mutex_1, torture_ww_mutex_2; 550 static struct ww_acquire_ctx *ww_acquire_ctxs; 551 552 static void torture_ww_mutex_init(void) 553 { 554 ww_mutex_init(&torture_ww_mutex_0, &torture_ww_class); 555 ww_mutex_init(&torture_ww_mutex_1, &torture_ww_class); 556 ww_mutex_init(&torture_ww_mutex_2, &torture_ww_class); 557 558 ww_acquire_ctxs = kmalloc_array(cxt.nrealwriters_stress, 559 sizeof(*ww_acquire_ctxs), 560 GFP_KERNEL); 561 if (!ww_acquire_ctxs) 562 VERBOSE_TOROUT_STRING("ww_acquire_ctx: Out of memory"); 563 } 564 565 static void torture_ww_mutex_exit(void) 566 { 567 kfree(ww_acquire_ctxs); 568 } 569 570 static int torture_ww_mutex_lock(int tid) 571 __acquires(torture_ww_mutex_0) 572 __acquires(torture_ww_mutex_1) 573 __acquires(torture_ww_mutex_2) 574 { 575 LIST_HEAD(list); 576 struct reorder_lock { 577 struct list_head link; 578 struct ww_mutex *lock; 579 } locks[3], *ll, *ln; 580 struct ww_acquire_ctx *ctx = &ww_acquire_ctxs[tid]; 581 582 locks[0].lock = &torture_ww_mutex_0; 583 list_add(&locks[0].link, &list); 584 585 locks[1].lock = &torture_ww_mutex_1; 586 list_add(&locks[1].link, &list); 587 588 locks[2].lock = &torture_ww_mutex_2; 589 list_add(&locks[2].link, &list); 590 591 ww_acquire_init(ctx, &torture_ww_class); 592 593 list_for_each_entry(ll, &list, link) { 594 int err; 595 596 err = ww_mutex_lock(ll->lock, ctx); 597 if (!err) 598 continue; 599 600 ln = ll; 601 list_for_each_entry_continue_reverse(ln, &list, link) 602 ww_mutex_unlock(ln->lock); 603 604 if (err != -EDEADLK) 605 return err; 606 607 ww_mutex_lock_slow(ll->lock, ctx); 608 list_move(&ll->link, &list); 609 } 610 611 return 0; 612 } 613 614 static void torture_ww_mutex_unlock(int tid) 615 __releases(torture_ww_mutex_0) 616 __releases(torture_ww_mutex_1) 617 __releases(torture_ww_mutex_2) 618 { 619 struct ww_acquire_ctx *ctx = &ww_acquire_ctxs[tid]; 620 621 ww_mutex_unlock(&torture_ww_mutex_0); 622 ww_mutex_unlock(&torture_ww_mutex_1); 623 ww_mutex_unlock(&torture_ww_mutex_2); 624 ww_acquire_fini(ctx); 625 } 626 627 static struct lock_torture_ops ww_mutex_lock_ops = { 628 .init = torture_ww_mutex_init, 629 .exit = torture_ww_mutex_exit, 630 .writelock = torture_ww_mutex_lock, 631 .write_delay = torture_mutex_delay, 632 .task_boost = torture_rt_boost, 633 .writeunlock = torture_ww_mutex_unlock, 634 .readlock = NULL, 635 .read_delay = NULL, 636 .readunlock = NULL, 637 .name = "ww_mutex_lock" 638 }; 639 640 #ifdef CONFIG_RT_MUTEXES 641 static DEFINE_RT_MUTEX(torture_rtmutex); 642 static struct rt_mutex torture_nested_rtmutexes[MAX_NESTED_LOCKS]; 643 static struct lock_class_key nested_rtmutex_keys[MAX_NESTED_LOCKS]; 644 645 static void torture_rtmutex_init(void) 646 { 647 int i; 648 649 for (i = 0; i < MAX_NESTED_LOCKS; i++) 650 __rt_mutex_init(&torture_nested_rtmutexes[i], __func__, 651 &nested_rtmutex_keys[i]); 652 } 653 654 static int torture_rtmutex_nested_lock(int tid __maybe_unused, 655 u32 lockset) 656 { 657 int i; 658 659 for (i = 0; i < nested_locks; i++) 660 if (lockset & (1 << i)) 661 rt_mutex_lock(&torture_nested_rtmutexes[i]); 662 return 0; 663 } 664 665 static int torture_rtmutex_lock(int tid __maybe_unused) 666 __acquires(torture_rtmutex) 667 { 668 rt_mutex_lock(&torture_rtmutex); 669 return 0; 670 } 671 672 static void torture_rtmutex_delay(struct torture_random_state *trsp) 673 { 674 const unsigned long shortdelay_us = 2; 675 676 /* 677 * We want a short delay mostly to emulate likely code, and 678 * we want a long delay occasionally to force massive contention. 679 */ 680 if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold))) 681 mdelay(long_hold); 682 if (!(torture_random(trsp) % 683 (cxt.nrealwriters_stress * 200 * shortdelay_us))) 684 udelay(shortdelay_us); 685 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000))) 686 torture_preempt_schedule(); /* Allow test to be preempted. */ 687 } 688 689 static void torture_rtmutex_unlock(int tid __maybe_unused) 690 __releases(torture_rtmutex) 691 { 692 rt_mutex_unlock(&torture_rtmutex); 693 } 694 695 static void torture_rt_boost_rtmutex(struct torture_random_state *trsp) 696 { 697 if (!rt_boost) 698 return; 699 700 __torture_rt_boost(trsp); 701 } 702 703 static void torture_rtmutex_nested_unlock(int tid __maybe_unused, 704 u32 lockset) 705 { 706 int i; 707 708 for (i = nested_locks - 1; i >= 0; i--) 709 if (lockset & (1 << i)) 710 rt_mutex_unlock(&torture_nested_rtmutexes[i]); 711 } 712 713 static struct lock_torture_ops rtmutex_lock_ops = { 714 .init = torture_rtmutex_init, 715 .nested_lock = torture_rtmutex_nested_lock, 716 .writelock = torture_rtmutex_lock, 717 .write_delay = torture_rtmutex_delay, 718 .task_boost = torture_rt_boost_rtmutex, 719 .writeunlock = torture_rtmutex_unlock, 720 .nested_unlock = torture_rtmutex_nested_unlock, 721 .readlock = NULL, 722 .read_delay = NULL, 723 .readunlock = NULL, 724 .name = "rtmutex_lock" 725 }; 726 #endif 727 728 static DECLARE_RWSEM(torture_rwsem); 729 static int torture_rwsem_down_write(int tid __maybe_unused) 730 __acquires(torture_rwsem) 731 { 732 down_write(&torture_rwsem); 733 return 0; 734 } 735 736 static void torture_rwsem_write_delay(struct torture_random_state *trsp) 737 { 738 /* We want a long delay occasionally to force massive contention. */ 739 if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold))) 740 mdelay(long_hold * 10); 741 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000))) 742 torture_preempt_schedule(); /* Allow test to be preempted. */ 743 } 744 745 static void torture_rwsem_up_write(int tid __maybe_unused) 746 __releases(torture_rwsem) 747 { 748 up_write(&torture_rwsem); 749 } 750 751 static int torture_rwsem_down_read(int tid __maybe_unused) 752 __acquires(torture_rwsem) 753 { 754 down_read(&torture_rwsem); 755 return 0; 756 } 757 758 static void torture_rwsem_read_delay(struct torture_random_state *trsp) 759 { 760 /* We want a long delay occasionally to force massive contention. */ 761 if (long_hold && !(torture_random(trsp) % (cxt.nrealreaders_stress * 2000 * long_hold))) 762 mdelay(long_hold * 2); 763 else 764 mdelay(long_hold / 2); 765 if (!(torture_random(trsp) % (cxt.nrealreaders_stress * 20000))) 766 torture_preempt_schedule(); /* Allow test to be preempted. */ 767 } 768 769 static void torture_rwsem_up_read(int tid __maybe_unused) 770 __releases(torture_rwsem) 771 { 772 up_read(&torture_rwsem); 773 } 774 775 static struct lock_torture_ops rwsem_lock_ops = { 776 .writelock = torture_rwsem_down_write, 777 .write_delay = torture_rwsem_write_delay, 778 .task_boost = torture_rt_boost, 779 .writeunlock = torture_rwsem_up_write, 780 .readlock = torture_rwsem_down_read, 781 .read_delay = torture_rwsem_read_delay, 782 .readunlock = torture_rwsem_up_read, 783 .name = "rwsem_lock" 784 }; 785 786 #include <linux/percpu-rwsem.h> 787 static struct percpu_rw_semaphore pcpu_rwsem; 788 789 static void torture_percpu_rwsem_init(void) 790 { 791 BUG_ON(percpu_init_rwsem(&pcpu_rwsem)); 792 } 793 794 static void torture_percpu_rwsem_exit(void) 795 { 796 percpu_free_rwsem(&pcpu_rwsem); 797 } 798 799 static int torture_percpu_rwsem_down_write(int tid __maybe_unused) 800 __acquires(pcpu_rwsem) 801 { 802 percpu_down_write(&pcpu_rwsem); 803 return 0; 804 } 805 806 static void torture_percpu_rwsem_up_write(int tid __maybe_unused) 807 __releases(pcpu_rwsem) 808 { 809 percpu_up_write(&pcpu_rwsem); 810 } 811 812 static int torture_percpu_rwsem_down_read(int tid __maybe_unused) 813 __acquires(pcpu_rwsem) 814 { 815 percpu_down_read(&pcpu_rwsem); 816 return 0; 817 } 818 819 static void torture_percpu_rwsem_up_read(int tid __maybe_unused) 820 __releases(pcpu_rwsem) 821 { 822 percpu_up_read(&pcpu_rwsem); 823 } 824 825 static struct lock_torture_ops percpu_rwsem_lock_ops = { 826 .init = torture_percpu_rwsem_init, 827 .exit = torture_percpu_rwsem_exit, 828 .writelock = torture_percpu_rwsem_down_write, 829 .write_delay = torture_rwsem_write_delay, 830 .task_boost = torture_rt_boost, 831 .writeunlock = torture_percpu_rwsem_up_write, 832 .readlock = torture_percpu_rwsem_down_read, 833 .read_delay = torture_rwsem_read_delay, 834 .readunlock = torture_percpu_rwsem_up_read, 835 .name = "percpu_rwsem_lock" 836 }; 837 838 /* 839 * Lock torture writer kthread. Repeatedly acquires and releases 840 * the lock, checking for duplicate acquisitions. 841 */ 842 static int lock_torture_writer(void *arg) 843 { 844 unsigned long j; 845 unsigned long j1; 846 u32 lockset_mask; 847 struct lock_stress_stats *lwsp = arg; 848 DEFINE_TORTURE_RANDOM(rand); 849 bool skip_main_lock; 850 int tid = lwsp - cxt.lwsa; 851 852 VERBOSE_TOROUT_STRING("lock_torture_writer task started"); 853 if (!rt_task(current)) 854 set_user_nice(current, MAX_NICE); 855 856 do { 857 if ((torture_random(&rand) & 0xfffff) == 0) 858 schedule_timeout_uninterruptible(1); 859 860 lockset_mask = torture_random(&rand); 861 /* 862 * When using nested_locks, we want to occasionally 863 * skip the main lock so we can avoid always serializing 864 * the lock chains on that central lock. By skipping the 865 * main lock occasionally, we can create different 866 * contention patterns (allowing for multiple disjoint 867 * blocked trees) 868 */ 869 skip_main_lock = (nested_locks && 870 !(torture_random(&rand) % 100)); 871 872 cxt.cur_ops->task_boost(&rand); 873 if (cxt.cur_ops->nested_lock) 874 cxt.cur_ops->nested_lock(tid, lockset_mask); 875 876 if (!skip_main_lock) { 877 if (acq_writer_lim > 0) 878 j = jiffies; 879 cxt.cur_ops->writelock(tid); 880 if (WARN_ON_ONCE(lock_is_write_held)) 881 lwsp->n_lock_fail++; 882 lock_is_write_held = true; 883 if (WARN_ON_ONCE(atomic_read(&lock_is_read_held))) 884 lwsp->n_lock_fail++; /* rare, but... */ 885 if (acq_writer_lim > 0) { 886 j1 = jiffies; 887 WARN_ONCE(time_after(j1, j + acq_writer_lim), 888 "%s: Lock acquisition took %lu jiffies.\n", 889 __func__, j1 - j); 890 } 891 lwsp->n_lock_acquired++; 892 893 cxt.cur_ops->write_delay(&rand); 894 895 lock_is_write_held = false; 896 WRITE_ONCE(last_lock_release, jiffies); 897 cxt.cur_ops->writeunlock(tid); 898 } 899 if (cxt.cur_ops->nested_unlock) 900 cxt.cur_ops->nested_unlock(tid, lockset_mask); 901 902 stutter_wait("lock_torture_writer"); 903 } while (!torture_must_stop()); 904 905 cxt.cur_ops->task_boost(NULL); /* reset prio */ 906 torture_kthread_stopping("lock_torture_writer"); 907 return 0; 908 } 909 910 /* 911 * Lock torture reader kthread. Repeatedly acquires and releases 912 * the reader lock. 913 */ 914 static int lock_torture_reader(void *arg) 915 { 916 struct lock_stress_stats *lrsp = arg; 917 int tid = lrsp - cxt.lrsa; 918 DEFINE_TORTURE_RANDOM(rand); 919 920 VERBOSE_TOROUT_STRING("lock_torture_reader task started"); 921 set_user_nice(current, MAX_NICE); 922 923 do { 924 if ((torture_random(&rand) & 0xfffff) == 0) 925 schedule_timeout_uninterruptible(1); 926 927 cxt.cur_ops->readlock(tid); 928 atomic_inc(&lock_is_read_held); 929 if (WARN_ON_ONCE(lock_is_write_held)) 930 lrsp->n_lock_fail++; /* rare, but... */ 931 932 lrsp->n_lock_acquired++; 933 cxt.cur_ops->read_delay(&rand); 934 atomic_dec(&lock_is_read_held); 935 cxt.cur_ops->readunlock(tid); 936 937 stutter_wait("lock_torture_reader"); 938 } while (!torture_must_stop()); 939 torture_kthread_stopping("lock_torture_reader"); 940 return 0; 941 } 942 943 /* 944 * Create an lock-torture-statistics message in the specified buffer. 945 */ 946 static void __torture_print_stats(char *page, 947 struct lock_stress_stats *statp, bool write) 948 { 949 long cur; 950 bool fail = false; 951 int i, n_stress; 952 long max = 0, min = statp ? data_race(statp[0].n_lock_acquired) : 0; 953 long long sum = 0; 954 955 n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress; 956 for (i = 0; i < n_stress; i++) { 957 if (data_race(statp[i].n_lock_fail)) 958 fail = true; 959 cur = data_race(statp[i].n_lock_acquired); 960 sum += cur; 961 if (max < cur) 962 max = cur; 963 if (min > cur) 964 min = cur; 965 } 966 page += sprintf(page, 967 "%s: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n", 968 write ? "Writes" : "Reads ", 969 sum, max, min, 970 !onoff_interval && max / 2 > min ? "???" : "", 971 fail, fail ? "!!!" : ""); 972 if (fail) 973 atomic_inc(&cxt.n_lock_torture_errors); 974 } 975 976 /* 977 * Print torture statistics. Caller must ensure that there is only one 978 * call to this function at a given time!!! This is normally accomplished 979 * by relying on the module system to only have one copy of the module 980 * loaded, and then by giving the lock_torture_stats kthread full control 981 * (or the init/cleanup functions when lock_torture_stats thread is not 982 * running). 983 */ 984 static void lock_torture_stats_print(void) 985 { 986 int size = cxt.nrealwriters_stress * 200 + 8192; 987 char *buf; 988 989 if (cxt.cur_ops->readlock) 990 size += cxt.nrealreaders_stress * 200 + 8192; 991 992 buf = kmalloc(size, GFP_KERNEL); 993 if (!buf) { 994 pr_err("lock_torture_stats_print: Out of memory, need: %d", 995 size); 996 return; 997 } 998 999 __torture_print_stats(buf, cxt.lwsa, true); 1000 pr_alert("%s", buf); 1001 kfree(buf); 1002 1003 if (cxt.cur_ops->readlock) { 1004 buf = kmalloc(size, GFP_KERNEL); 1005 if (!buf) { 1006 pr_err("lock_torture_stats_print: Out of memory, need: %d", 1007 size); 1008 return; 1009 } 1010 1011 __torture_print_stats(buf, cxt.lrsa, false); 1012 pr_alert("%s", buf); 1013 kfree(buf); 1014 } 1015 } 1016 1017 /* 1018 * Periodically prints torture statistics, if periodic statistics printing 1019 * was specified via the stat_interval module parameter. 1020 * 1021 * No need to worry about fullstop here, since this one doesn't reference 1022 * volatile state or register callbacks. 1023 */ 1024 static int lock_torture_stats(void *arg) 1025 { 1026 VERBOSE_TOROUT_STRING("lock_torture_stats task started"); 1027 do { 1028 schedule_timeout_interruptible(stat_interval * HZ); 1029 lock_torture_stats_print(); 1030 torture_shutdown_absorb("lock_torture_stats"); 1031 } while (!torture_must_stop()); 1032 torture_kthread_stopping("lock_torture_stats"); 1033 return 0; 1034 } 1035 1036 1037 static inline void 1038 lock_torture_print_module_parms(struct lock_torture_ops *cur_ops, 1039 const char *tag) 1040 { 1041 static cpumask_t cpumask_all; 1042 cpumask_t *rcmp = cpumask_nonempty(bind_readers) ? bind_readers : &cpumask_all; 1043 cpumask_t *wcmp = cpumask_nonempty(bind_writers) ? bind_writers : &cpumask_all; 1044 1045 cpumask_setall(&cpumask_all); 1046 pr_alert("%s" TORTURE_FLAG 1047 "--- %s%s: acq_writer_lim=%d bind_readers=%*pbl bind_writers=%*pbl call_rcu_chains=%d long_hold=%d nested_locks=%d nreaders_stress=%d nwriters_stress=%d onoff_holdoff=%d onoff_interval=%d rt_boost=%d rt_boost_factor=%d shuffle_interval=%d shutdown_secs=%d stat_interval=%d stutter=%d verbose=%d writer_fifo=%d\n", 1048 torture_type, tag, cxt.debug_lock ? " [debug]": "", 1049 acq_writer_lim, cpumask_pr_args(rcmp), cpumask_pr_args(wcmp), 1050 call_rcu_chains, long_hold, nested_locks, cxt.nrealreaders_stress, 1051 cxt.nrealwriters_stress, onoff_holdoff, onoff_interval, rt_boost, 1052 rt_boost_factor, shuffle_interval, shutdown_secs, stat_interval, stutter, 1053 verbose, writer_fifo); 1054 } 1055 1056 // If requested, maintain call_rcu() chains to keep a grace period always 1057 // in flight. These increase the probability of getting an RCU CPU stall 1058 // warning and associated diagnostics when a locking primitive stalls. 1059 1060 static void call_rcu_chain_cb(struct rcu_head *rhp) 1061 { 1062 struct call_rcu_chain *crcp = container_of(rhp, struct call_rcu_chain, crc_rh); 1063 1064 if (!smp_load_acquire(&crcp->crc_stop)) { 1065 (void)start_poll_synchronize_rcu(); // Start one grace period... 1066 call_rcu(&crcp->crc_rh, call_rcu_chain_cb); // ... and later start another. 1067 } 1068 } 1069 1070 // Start the requested number of call_rcu() chains. 1071 static int call_rcu_chain_init(void) 1072 { 1073 int i; 1074 1075 if (call_rcu_chains <= 0) 1076 return 0; 1077 call_rcu_chain = kcalloc(call_rcu_chains, sizeof(*call_rcu_chain), GFP_KERNEL); 1078 if (!call_rcu_chain) 1079 return -ENOMEM; 1080 for (i = 0; i < call_rcu_chains; i++) { 1081 call_rcu_chain[i].crc_stop = false; 1082 call_rcu(&call_rcu_chain[i].crc_rh, call_rcu_chain_cb); 1083 } 1084 return 0; 1085 } 1086 1087 // Stop all of the call_rcu() chains. 1088 static void call_rcu_chain_cleanup(void) 1089 { 1090 int i; 1091 1092 if (!call_rcu_chain) 1093 return; 1094 for (i = 0; i < call_rcu_chains; i++) 1095 smp_store_release(&call_rcu_chain[i].crc_stop, true); 1096 rcu_barrier(); 1097 kfree(call_rcu_chain); 1098 call_rcu_chain = NULL; 1099 } 1100 1101 static void lock_torture_cleanup(void) 1102 { 1103 int i; 1104 1105 if (torture_cleanup_begin()) 1106 return; 1107 1108 /* 1109 * Indicates early cleanup, meaning that the test has not run, 1110 * such as when passing bogus args when loading the module. 1111 * However cxt->cur_ops.init() may have been invoked, so beside 1112 * perform the underlying torture-specific cleanups, cur_ops.exit() 1113 * will be invoked if needed. 1114 */ 1115 if (!cxt.lwsa && !cxt.lrsa) 1116 goto end; 1117 1118 if (writer_tasks) { 1119 for (i = 0; i < cxt.nrealwriters_stress; i++) 1120 torture_stop_kthread(lock_torture_writer, writer_tasks[i]); 1121 kfree(writer_tasks); 1122 writer_tasks = NULL; 1123 } 1124 1125 if (reader_tasks) { 1126 for (i = 0; i < cxt.nrealreaders_stress; i++) 1127 torture_stop_kthread(lock_torture_reader, 1128 reader_tasks[i]); 1129 kfree(reader_tasks); 1130 reader_tasks = NULL; 1131 } 1132 1133 torture_stop_kthread(lock_torture_stats, stats_task); 1134 lock_torture_stats_print(); /* -After- the stats thread is stopped! */ 1135 1136 if (atomic_read(&cxt.n_lock_torture_errors)) 1137 lock_torture_print_module_parms(cxt.cur_ops, 1138 "End of test: FAILURE"); 1139 else if (torture_onoff_failures()) 1140 lock_torture_print_module_parms(cxt.cur_ops, 1141 "End of test: LOCK_HOTPLUG"); 1142 else 1143 lock_torture_print_module_parms(cxt.cur_ops, 1144 "End of test: SUCCESS"); 1145 1146 kfree(cxt.lwsa); 1147 cxt.lwsa = NULL; 1148 kfree(cxt.lrsa); 1149 cxt.lrsa = NULL; 1150 1151 call_rcu_chain_cleanup(); 1152 1153 end: 1154 if (cxt.init_called) { 1155 if (cxt.cur_ops->exit) 1156 cxt.cur_ops->exit(); 1157 cxt.init_called = false; 1158 } 1159 torture_cleanup_end(); 1160 } 1161 1162 static int __init lock_torture_init(void) 1163 { 1164 int i, j; 1165 int firsterr = 0; 1166 static struct lock_torture_ops *torture_ops[] = { 1167 &lock_busted_ops, 1168 &spin_lock_ops, &spin_lock_irq_ops, 1169 &raw_spin_lock_ops, &raw_spin_lock_irq_ops, 1170 &rw_lock_ops, &rw_lock_irq_ops, 1171 &mutex_lock_ops, 1172 &ww_mutex_lock_ops, 1173 #ifdef CONFIG_RT_MUTEXES 1174 &rtmutex_lock_ops, 1175 #endif 1176 &rwsem_lock_ops, 1177 &percpu_rwsem_lock_ops, 1178 }; 1179 1180 if (!torture_init_begin(torture_type, verbose)) 1181 return -EBUSY; 1182 1183 /* Process args and tell the world that the torturer is on the job. */ 1184 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) { 1185 cxt.cur_ops = torture_ops[i]; 1186 if (strcmp(torture_type, cxt.cur_ops->name) == 0) 1187 break; 1188 } 1189 if (i == ARRAY_SIZE(torture_ops)) { 1190 pr_alert("lock-torture: invalid torture type: \"%s\"\n", 1191 torture_type); 1192 pr_alert("lock-torture types:"); 1193 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) 1194 pr_alert(" %s", torture_ops[i]->name); 1195 pr_alert("\n"); 1196 firsterr = -EINVAL; 1197 goto unwind; 1198 } 1199 1200 if (nwriters_stress == 0 && 1201 (!cxt.cur_ops->readlock || nreaders_stress == 0)) { 1202 pr_alert("lock-torture: must run at least one locking thread\n"); 1203 firsterr = -EINVAL; 1204 goto unwind; 1205 } 1206 1207 if (nwriters_stress >= 0) 1208 cxt.nrealwriters_stress = nwriters_stress; 1209 else 1210 cxt.nrealwriters_stress = 2 * num_online_cpus(); 1211 1212 if (cxt.cur_ops->init) { 1213 cxt.cur_ops->init(); 1214 cxt.init_called = true; 1215 } 1216 1217 #ifdef CONFIG_DEBUG_MUTEXES 1218 if (str_has_prefix(torture_type, "mutex")) 1219 cxt.debug_lock = true; 1220 #endif 1221 #ifdef CONFIG_DEBUG_RT_MUTEXES 1222 if (str_has_prefix(torture_type, "rtmutex")) 1223 cxt.debug_lock = true; 1224 #endif 1225 #ifdef CONFIG_DEBUG_SPINLOCK 1226 if ((str_has_prefix(torture_type, "spin")) || 1227 (str_has_prefix(torture_type, "rw_lock"))) 1228 cxt.debug_lock = true; 1229 #endif 1230 1231 /* Initialize the statistics so that each run gets its own numbers. */ 1232 if (nwriters_stress) { 1233 lock_is_write_held = false; 1234 cxt.lwsa = kmalloc_array(cxt.nrealwriters_stress, 1235 sizeof(*cxt.lwsa), 1236 GFP_KERNEL); 1237 if (cxt.lwsa == NULL) { 1238 VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory"); 1239 firsterr = -ENOMEM; 1240 goto unwind; 1241 } 1242 1243 for (i = 0; i < cxt.nrealwriters_stress; i++) { 1244 cxt.lwsa[i].n_lock_fail = 0; 1245 cxt.lwsa[i].n_lock_acquired = 0; 1246 } 1247 } 1248 1249 if (cxt.cur_ops->readlock) { 1250 if (nreaders_stress >= 0) 1251 cxt.nrealreaders_stress = nreaders_stress; 1252 else { 1253 /* 1254 * By default distribute evenly the number of 1255 * readers and writers. We still run the same number 1256 * of threads as the writer-only locks default. 1257 */ 1258 if (nwriters_stress < 0) /* user doesn't care */ 1259 cxt.nrealwriters_stress = num_online_cpus(); 1260 cxt.nrealreaders_stress = cxt.nrealwriters_stress; 1261 } 1262 1263 if (nreaders_stress) { 1264 cxt.lrsa = kmalloc_array(cxt.nrealreaders_stress, 1265 sizeof(*cxt.lrsa), 1266 GFP_KERNEL); 1267 if (cxt.lrsa == NULL) { 1268 VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory"); 1269 firsterr = -ENOMEM; 1270 kfree(cxt.lwsa); 1271 cxt.lwsa = NULL; 1272 goto unwind; 1273 } 1274 1275 for (i = 0; i < cxt.nrealreaders_stress; i++) { 1276 cxt.lrsa[i].n_lock_fail = 0; 1277 cxt.lrsa[i].n_lock_acquired = 0; 1278 } 1279 } 1280 } 1281 1282 firsterr = call_rcu_chain_init(); 1283 if (torture_init_error(firsterr)) 1284 goto unwind; 1285 1286 lock_torture_print_module_parms(cxt.cur_ops, "Start of test"); 1287 1288 /* Prepare torture context. */ 1289 if (onoff_interval > 0) { 1290 firsterr = torture_onoff_init(onoff_holdoff * HZ, 1291 onoff_interval * HZ, NULL); 1292 if (torture_init_error(firsterr)) 1293 goto unwind; 1294 } 1295 if (shuffle_interval > 0) { 1296 firsterr = torture_shuffle_init(shuffle_interval); 1297 if (torture_init_error(firsterr)) 1298 goto unwind; 1299 } 1300 if (shutdown_secs > 0) { 1301 firsterr = torture_shutdown_init(shutdown_secs, 1302 lock_torture_cleanup); 1303 if (torture_init_error(firsterr)) 1304 goto unwind; 1305 } 1306 if (stutter > 0) { 1307 firsterr = torture_stutter_init(stutter, stutter); 1308 if (torture_init_error(firsterr)) 1309 goto unwind; 1310 } 1311 1312 if (nwriters_stress) { 1313 writer_tasks = kcalloc(cxt.nrealwriters_stress, 1314 sizeof(writer_tasks[0]), 1315 GFP_KERNEL); 1316 if (writer_tasks == NULL) { 1317 TOROUT_ERRSTRING("writer_tasks: Out of memory"); 1318 firsterr = -ENOMEM; 1319 goto unwind; 1320 } 1321 } 1322 1323 /* cap nested_locks to MAX_NESTED_LOCKS */ 1324 if (nested_locks > MAX_NESTED_LOCKS) 1325 nested_locks = MAX_NESTED_LOCKS; 1326 1327 if (cxt.cur_ops->readlock) { 1328 reader_tasks = kcalloc(cxt.nrealreaders_stress, 1329 sizeof(reader_tasks[0]), 1330 GFP_KERNEL); 1331 if (reader_tasks == NULL) { 1332 TOROUT_ERRSTRING("reader_tasks: Out of memory"); 1333 kfree(writer_tasks); 1334 writer_tasks = NULL; 1335 firsterr = -ENOMEM; 1336 goto unwind; 1337 } 1338 } 1339 1340 /* 1341 * Create the kthreads and start torturing (oh, those poor little locks). 1342 * 1343 * TODO: Note that we interleave writers with readers, giving writers a 1344 * slight advantage, by creating its kthread first. This can be modified 1345 * for very specific needs, or even let the user choose the policy, if 1346 * ever wanted. 1347 */ 1348 for (i = 0, j = 0; i < cxt.nrealwriters_stress || 1349 j < cxt.nrealreaders_stress; i++, j++) { 1350 if (i >= cxt.nrealwriters_stress) 1351 goto create_reader; 1352 1353 /* Create writer. */ 1354 firsterr = torture_create_kthread_cb(lock_torture_writer, &cxt.lwsa[i], 1355 writer_tasks[i], 1356 writer_fifo ? sched_set_fifo : NULL); 1357 if (torture_init_error(firsterr)) 1358 goto unwind; 1359 if (cpumask_nonempty(bind_writers)) 1360 torture_sched_setaffinity(writer_tasks[i]->pid, bind_writers); 1361 1362 create_reader: 1363 if (cxt.cur_ops->readlock == NULL || (j >= cxt.nrealreaders_stress)) 1364 continue; 1365 /* Create reader. */ 1366 firsterr = torture_create_kthread(lock_torture_reader, &cxt.lrsa[j], 1367 reader_tasks[j]); 1368 if (torture_init_error(firsterr)) 1369 goto unwind; 1370 if (cpumask_nonempty(bind_readers)) 1371 torture_sched_setaffinity(reader_tasks[j]->pid, bind_readers); 1372 } 1373 if (stat_interval > 0) { 1374 firsterr = torture_create_kthread(lock_torture_stats, NULL, 1375 stats_task); 1376 if (torture_init_error(firsterr)) 1377 goto unwind; 1378 } 1379 torture_init_end(); 1380 return 0; 1381 1382 unwind: 1383 torture_init_end(); 1384 lock_torture_cleanup(); 1385 if (shutdown_secs) { 1386 WARN_ON(!IS_MODULE(CONFIG_LOCK_TORTURE_TEST)); 1387 kernel_power_off(); 1388 } 1389 return firsterr; 1390 } 1391 1392 module_init(lock_torture_init); 1393 module_exit(lock_torture_cleanup); 1394