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_DESCRIPTION("torture test facility for locking"); 34 MODULE_LICENSE("GPL"); 35 MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>"); 36 37 torture_param(int, acq_writer_lim, 0, "Write_acquisition time limit (jiffies)."); 38 torture_param(int, call_rcu_chains, 0, "Self-propagate call_rcu() chains during test (0=disable)."); 39 torture_param(int, long_hold, 100, "Do occasional long hold of lock (ms), 0=disable"); 40 torture_param(int, nested_locks, 0, "Number of nested locks (max = 8)"); 41 torture_param(int, nreaders_stress, -1, "Number of read-locking stress-test threads"); 42 torture_param(int, nwriters_stress, -1, "Number of write-locking stress-test threads"); 43 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)"); 44 torture_param(int, onoff_interval, 0, "Time between CPU hotplugs (s), 0=disable"); 45 torture_param(int, rt_boost, 2, 46 "Do periodic rt-boost. 0=Disable, 1=Only for rt_mutex, 2=For all lock types."); 47 torture_param(int, rt_boost_factor, 50, "A factor determining how often rt-boost happens."); 48 torture_param(int, shuffle_interval, 3, "Number of jiffies between shuffles, 0=disable"); 49 torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable."); 50 torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s"); 51 torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable"); 52 torture_param(int, verbose, 1, "Enable verbose debugging printk()s"); 53 torture_param(int, writer_fifo, 0, "Run writers at sched_set_fifo() priority"); 54 /* Going much higher trips "BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!" errors */ 55 #define MAX_NESTED_LOCKS 8 56 57 static char *torture_type = IS_ENABLED(CONFIG_PREEMPT_RT) ? "raw_spin_lock" : "spin_lock"; 58 module_param(torture_type, charp, 0444); 59 MODULE_PARM_DESC(torture_type, 60 "Type of lock to torture (spin_lock, spin_lock_irq, mutex_lock, ...)"); 61 62 static cpumask_var_t bind_readers; // Bind the readers to the specified set of CPUs. 63 static cpumask_var_t bind_writers; // Bind the writers to the specified set of CPUs. 64 65 // Parse a cpumask kernel parameter. If there are more users later on, 66 // this might need to got to a more central location. 67 static int param_set_cpumask(const char *val, const struct kernel_param *kp) 68 { 69 cpumask_var_t *cm_bind = kp->arg; 70 int ret; 71 char *s; 72 73 if (!alloc_cpumask_var(cm_bind, GFP_KERNEL)) { 74 s = "Out of memory"; 75 ret = -ENOMEM; 76 goto out_err; 77 } 78 ret = cpulist_parse(val, *cm_bind); 79 if (!ret) 80 return ret; 81 s = "Bad CPU range"; 82 out_err: 83 pr_warn("%s: %s, all CPUs set\n", kp->name, s); 84 cpumask_setall(*cm_bind); 85 return ret; 86 } 87 88 // Output a cpumask kernel parameter. 89 static int param_get_cpumask(char *buffer, const struct kernel_param *kp) 90 { 91 cpumask_var_t *cm_bind = kp->arg; 92 93 return sprintf(buffer, "%*pbl", cpumask_pr_args(*cm_bind)); 94 } 95 96 static bool cpumask_nonempty(cpumask_var_t mask) 97 { 98 return cpumask_available(mask) && !cpumask_empty(mask); 99 } 100 101 static const struct kernel_param_ops lt_bind_ops = { 102 .set = param_set_cpumask, 103 .get = param_get_cpumask, 104 }; 105 106 module_param_cb(bind_readers, <_bind_ops, &bind_readers, 0444); 107 module_param_cb(bind_writers, <_bind_ops, &bind_writers, 0444); 108 109 long torture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask, bool dowarn); 110 111 static struct task_struct *stats_task; 112 static struct task_struct **writer_tasks; 113 static struct task_struct **reader_tasks; 114 115 static bool lock_is_write_held; 116 static atomic_t lock_is_read_held; 117 static unsigned long last_lock_release; 118 119 struct lock_stress_stats { 120 long n_lock_fail; 121 long n_lock_acquired; 122 }; 123 124 struct call_rcu_chain { 125 struct rcu_head crc_rh; 126 bool crc_stop; 127 }; 128 struct call_rcu_chain *call_rcu_chain_list; 129 130 /* Forward reference. */ 131 static void lock_torture_cleanup(void); 132 133 /* 134 * Operations vector for selecting different types of tests. 135 */ 136 struct lock_torture_ops { 137 void (*init)(void); 138 void (*exit)(void); 139 int (*nested_lock)(int tid, u32 lockset); 140 int (*writelock)(int tid); 141 void (*write_delay)(struct torture_random_state *trsp); 142 void (*task_boost)(struct torture_random_state *trsp); 143 void (*writeunlock)(int tid); 144 void (*nested_unlock)(int tid, u32 lockset); 145 int (*readlock)(int tid); 146 void (*read_delay)(struct torture_random_state *trsp); 147 void (*readunlock)(int tid); 148 149 unsigned long flags; /* for irq spinlocks */ 150 const char *name; 151 }; 152 153 struct lock_torture_cxt { 154 int nrealwriters_stress; 155 int nrealreaders_stress; 156 bool debug_lock; 157 bool init_called; 158 atomic_t n_lock_torture_errors; 159 struct lock_torture_ops *cur_ops; 160 struct lock_stress_stats *lwsa; /* writer statistics */ 161 struct lock_stress_stats *lrsa; /* reader statistics */ 162 }; 163 static struct lock_torture_cxt cxt = { 0, 0, false, false, 164 ATOMIC_INIT(0), 165 NULL, NULL}; 166 /* 167 * Definitions for lock torture testing. 168 */ 169 170 static int torture_lock_busted_write_lock(int tid __maybe_unused) 171 { 172 return 0; /* BUGGY, do not use in real life!!! */ 173 } 174 175 static void torture_lock_busted_write_delay(struct torture_random_state *trsp) 176 { 177 /* We want a long delay occasionally to force massive contention. */ 178 if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold))) 179 mdelay(long_hold); 180 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000))) 181 torture_preempt_schedule(); /* Allow test to be preempted. */ 182 } 183 184 static void torture_lock_busted_write_unlock(int tid __maybe_unused) 185 { 186 /* BUGGY, do not use in real life!!! */ 187 } 188 189 static void __torture_rt_boost(struct torture_random_state *trsp) 190 { 191 const unsigned int factor = rt_boost_factor; 192 193 if (!rt_task(current)) { 194 /* 195 * Boost priority once every rt_boost_factor operations. When 196 * the task tries to take the lock, the rtmutex it will account 197 * for the new priority, and do any corresponding pi-dance. 198 */ 199 if (trsp && !(torture_random(trsp) % 200 (cxt.nrealwriters_stress * factor))) { 201 sched_set_fifo(current); 202 } else /* common case, do nothing */ 203 return; 204 } else { 205 /* 206 * The task will remain boosted for another 10 * rt_boost_factor 207 * operations, then restored back to its original prio, and so 208 * forth. 209 * 210 * When @trsp is nil, we want to force-reset the task for 211 * stopping the kthread. 212 */ 213 if (!trsp || !(torture_random(trsp) % 214 (cxt.nrealwriters_stress * factor * 2))) { 215 sched_set_normal(current, 0); 216 } else /* common case, do nothing */ 217 return; 218 } 219 } 220 221 static void torture_rt_boost(struct torture_random_state *trsp) 222 { 223 if (rt_boost != 2) 224 return; 225 226 __torture_rt_boost(trsp); 227 } 228 229 static struct lock_torture_ops lock_busted_ops = { 230 .writelock = torture_lock_busted_write_lock, 231 .write_delay = torture_lock_busted_write_delay, 232 .task_boost = torture_rt_boost, 233 .writeunlock = torture_lock_busted_write_unlock, 234 .readlock = NULL, 235 .read_delay = NULL, 236 .readunlock = NULL, 237 .name = "lock_busted" 238 }; 239 240 static DEFINE_SPINLOCK(torture_spinlock); 241 242 static int torture_spin_lock_write_lock(int tid __maybe_unused) 243 __acquires(torture_spinlock) 244 { 245 spin_lock(&torture_spinlock); 246 return 0; 247 } 248 249 static void torture_spin_lock_write_delay(struct torture_random_state *trsp) 250 { 251 const unsigned long shortdelay_us = 2; 252 unsigned long j; 253 254 /* We want a short delay mostly to emulate likely code, and 255 * we want a long delay occasionally to force massive contention. 256 */ 257 if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold))) { 258 j = jiffies; 259 mdelay(long_hold); 260 pr_alert("%s: delay = %lu jiffies.\n", __func__, jiffies - j); 261 } 262 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 200 * shortdelay_us))) 263 udelay(shortdelay_us); 264 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000))) 265 torture_preempt_schedule(); /* Allow test to be preempted. */ 266 } 267 268 static void torture_spin_lock_write_unlock(int tid __maybe_unused) 269 __releases(torture_spinlock) 270 { 271 spin_unlock(&torture_spinlock); 272 } 273 274 static struct lock_torture_ops spin_lock_ops = { 275 .writelock = torture_spin_lock_write_lock, 276 .write_delay = torture_spin_lock_write_delay, 277 .task_boost = torture_rt_boost, 278 .writeunlock = torture_spin_lock_write_unlock, 279 .readlock = NULL, 280 .read_delay = NULL, 281 .readunlock = NULL, 282 .name = "spin_lock" 283 }; 284 285 static int torture_spin_lock_write_lock_irq(int tid __maybe_unused) 286 __acquires(torture_spinlock) 287 { 288 unsigned long flags; 289 290 spin_lock_irqsave(&torture_spinlock, flags); 291 cxt.cur_ops->flags = flags; 292 return 0; 293 } 294 295 static void torture_lock_spin_write_unlock_irq(int tid __maybe_unused) 296 __releases(torture_spinlock) 297 { 298 spin_unlock_irqrestore(&torture_spinlock, cxt.cur_ops->flags); 299 } 300 301 static struct lock_torture_ops spin_lock_irq_ops = { 302 .writelock = torture_spin_lock_write_lock_irq, 303 .write_delay = torture_spin_lock_write_delay, 304 .task_boost = torture_rt_boost, 305 .writeunlock = torture_lock_spin_write_unlock_irq, 306 .readlock = NULL, 307 .read_delay = NULL, 308 .readunlock = NULL, 309 .name = "spin_lock_irq" 310 }; 311 312 static DEFINE_RAW_SPINLOCK(torture_raw_spinlock); 313 314 static int torture_raw_spin_lock_write_lock(int tid __maybe_unused) 315 __acquires(torture_raw_spinlock) 316 { 317 raw_spin_lock(&torture_raw_spinlock); 318 return 0; 319 } 320 321 static void torture_raw_spin_lock_write_unlock(int tid __maybe_unused) 322 __releases(torture_raw_spinlock) 323 { 324 raw_spin_unlock(&torture_raw_spinlock); 325 } 326 327 static struct lock_torture_ops raw_spin_lock_ops = { 328 .writelock = torture_raw_spin_lock_write_lock, 329 .write_delay = torture_spin_lock_write_delay, 330 .task_boost = torture_rt_boost, 331 .writeunlock = torture_raw_spin_lock_write_unlock, 332 .readlock = NULL, 333 .read_delay = NULL, 334 .readunlock = NULL, 335 .name = "raw_spin_lock" 336 }; 337 338 static int torture_raw_spin_lock_write_lock_irq(int tid __maybe_unused) 339 __acquires(torture_raw_spinlock) 340 { 341 unsigned long flags; 342 343 raw_spin_lock_irqsave(&torture_raw_spinlock, flags); 344 cxt.cur_ops->flags = flags; 345 return 0; 346 } 347 348 static void torture_raw_spin_lock_write_unlock_irq(int tid __maybe_unused) 349 __releases(torture_raw_spinlock) 350 { 351 raw_spin_unlock_irqrestore(&torture_raw_spinlock, cxt.cur_ops->flags); 352 } 353 354 static struct lock_torture_ops raw_spin_lock_irq_ops = { 355 .writelock = torture_raw_spin_lock_write_lock_irq, 356 .write_delay = torture_spin_lock_write_delay, 357 .task_boost = torture_rt_boost, 358 .writeunlock = torture_raw_spin_lock_write_unlock_irq, 359 .readlock = NULL, 360 .read_delay = NULL, 361 .readunlock = NULL, 362 .name = "raw_spin_lock_irq" 363 }; 364 365 #ifdef CONFIG_BPF_SYSCALL 366 367 #include <asm/rqspinlock.h> 368 static rqspinlock_t rqspinlock; 369 370 static int torture_raw_res_spin_write_lock(int tid __maybe_unused) 371 { 372 raw_res_spin_lock(&rqspinlock); 373 return 0; 374 } 375 376 static void torture_raw_res_spin_write_unlock(int tid __maybe_unused) 377 { 378 raw_res_spin_unlock(&rqspinlock); 379 } 380 381 static struct lock_torture_ops raw_res_spin_lock_ops = { 382 .writelock = torture_raw_res_spin_write_lock, 383 .write_delay = torture_spin_lock_write_delay, 384 .task_boost = torture_rt_boost, 385 .writeunlock = torture_raw_res_spin_write_unlock, 386 .readlock = NULL, 387 .read_delay = NULL, 388 .readunlock = NULL, 389 .name = "raw_res_spin_lock" 390 }; 391 392 static int torture_raw_res_spin_write_lock_irq(int tid __maybe_unused) 393 { 394 unsigned long flags; 395 396 raw_res_spin_lock_irqsave(&rqspinlock, flags); 397 cxt.cur_ops->flags = flags; 398 return 0; 399 } 400 401 static void torture_raw_res_spin_write_unlock_irq(int tid __maybe_unused) 402 { 403 raw_res_spin_unlock_irqrestore(&rqspinlock, cxt.cur_ops->flags); 404 } 405 406 static struct lock_torture_ops raw_res_spin_lock_irq_ops = { 407 .writelock = torture_raw_res_spin_write_lock_irq, 408 .write_delay = torture_spin_lock_write_delay, 409 .task_boost = torture_rt_boost, 410 .writeunlock = torture_raw_res_spin_write_unlock_irq, 411 .readlock = NULL, 412 .read_delay = NULL, 413 .readunlock = NULL, 414 .name = "raw_res_spin_lock_irq" 415 }; 416 417 #endif 418 419 static DEFINE_RWLOCK(torture_rwlock); 420 421 static int torture_rwlock_write_lock(int tid __maybe_unused) 422 __acquires(torture_rwlock) 423 { 424 write_lock(&torture_rwlock); 425 return 0; 426 } 427 428 static void torture_rwlock_write_delay(struct torture_random_state *trsp) 429 { 430 const unsigned long shortdelay_us = 2; 431 432 /* We want a short delay mostly to emulate likely code, and 433 * we want a long delay occasionally to force massive contention. 434 */ 435 if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold))) 436 mdelay(long_hold); 437 else 438 udelay(shortdelay_us); 439 } 440 441 static void torture_rwlock_write_unlock(int tid __maybe_unused) 442 __releases(torture_rwlock) 443 { 444 write_unlock(&torture_rwlock); 445 } 446 447 static int torture_rwlock_read_lock(int tid __maybe_unused) 448 __acquires(torture_rwlock) 449 { 450 read_lock(&torture_rwlock); 451 return 0; 452 } 453 454 static void torture_rwlock_read_delay(struct torture_random_state *trsp) 455 { 456 const unsigned long shortdelay_us = 10; 457 458 /* We want a short delay mostly to emulate likely code, and 459 * we want a long delay occasionally to force massive contention. 460 */ 461 if (long_hold && !(torture_random(trsp) % (cxt.nrealreaders_stress * 2000 * long_hold))) 462 mdelay(long_hold); 463 else 464 udelay(shortdelay_us); 465 } 466 467 static void torture_rwlock_read_unlock(int tid __maybe_unused) 468 __releases(torture_rwlock) 469 { 470 read_unlock(&torture_rwlock); 471 } 472 473 static struct lock_torture_ops rw_lock_ops = { 474 .writelock = torture_rwlock_write_lock, 475 .write_delay = torture_rwlock_write_delay, 476 .task_boost = torture_rt_boost, 477 .writeunlock = torture_rwlock_write_unlock, 478 .readlock = torture_rwlock_read_lock, 479 .read_delay = torture_rwlock_read_delay, 480 .readunlock = torture_rwlock_read_unlock, 481 .name = "rw_lock" 482 }; 483 484 static int torture_rwlock_write_lock_irq(int tid __maybe_unused) 485 __acquires(torture_rwlock) 486 { 487 unsigned long flags; 488 489 write_lock_irqsave(&torture_rwlock, flags); 490 cxt.cur_ops->flags = flags; 491 return 0; 492 } 493 494 static void torture_rwlock_write_unlock_irq(int tid __maybe_unused) 495 __releases(torture_rwlock) 496 { 497 write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags); 498 } 499 500 static int torture_rwlock_read_lock_irq(int tid __maybe_unused) 501 __acquires(torture_rwlock) 502 { 503 unsigned long flags; 504 505 read_lock_irqsave(&torture_rwlock, flags); 506 cxt.cur_ops->flags = flags; 507 return 0; 508 } 509 510 static void torture_rwlock_read_unlock_irq(int tid __maybe_unused) 511 __releases(torture_rwlock) 512 { 513 read_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags); 514 } 515 516 static struct lock_torture_ops rw_lock_irq_ops = { 517 .writelock = torture_rwlock_write_lock_irq, 518 .write_delay = torture_rwlock_write_delay, 519 .task_boost = torture_rt_boost, 520 .writeunlock = torture_rwlock_write_unlock_irq, 521 .readlock = torture_rwlock_read_lock_irq, 522 .read_delay = torture_rwlock_read_delay, 523 .readunlock = torture_rwlock_read_unlock_irq, 524 .name = "rw_lock_irq" 525 }; 526 527 static DEFINE_MUTEX(torture_mutex); 528 static struct mutex torture_nested_mutexes[MAX_NESTED_LOCKS]; 529 static struct lock_class_key nested_mutex_keys[MAX_NESTED_LOCKS]; 530 531 static void torture_mutex_init(void) 532 { 533 int i; 534 535 for (i = 0; i < MAX_NESTED_LOCKS; i++) 536 __mutex_init(&torture_nested_mutexes[i], __func__, 537 &nested_mutex_keys[i]); 538 } 539 540 static int torture_mutex_nested_lock(int tid __maybe_unused, 541 u32 lockset) 542 { 543 int i; 544 545 for (i = 0; i < nested_locks; i++) 546 if (lockset & (1 << i)) 547 mutex_lock(&torture_nested_mutexes[i]); 548 return 0; 549 } 550 551 static int torture_mutex_lock(int tid __maybe_unused) 552 __acquires(torture_mutex) 553 { 554 mutex_lock(&torture_mutex); 555 return 0; 556 } 557 558 static void torture_mutex_delay(struct torture_random_state *trsp) 559 { 560 /* We want a long delay occasionally to force massive contention. */ 561 if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold))) 562 mdelay(long_hold * 5); 563 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000))) 564 torture_preempt_schedule(); /* Allow test to be preempted. */ 565 } 566 567 static void torture_mutex_unlock(int tid __maybe_unused) 568 __releases(torture_mutex) 569 { 570 mutex_unlock(&torture_mutex); 571 } 572 573 static void torture_mutex_nested_unlock(int tid __maybe_unused, 574 u32 lockset) 575 { 576 int i; 577 578 for (i = nested_locks - 1; i >= 0; i--) 579 if (lockset & (1 << i)) 580 mutex_unlock(&torture_nested_mutexes[i]); 581 } 582 583 static struct lock_torture_ops mutex_lock_ops = { 584 .init = torture_mutex_init, 585 .nested_lock = torture_mutex_nested_lock, 586 .writelock = torture_mutex_lock, 587 .write_delay = torture_mutex_delay, 588 .task_boost = torture_rt_boost, 589 .writeunlock = torture_mutex_unlock, 590 .nested_unlock = torture_mutex_nested_unlock, 591 .readlock = NULL, 592 .read_delay = NULL, 593 .readunlock = NULL, 594 .name = "mutex_lock" 595 }; 596 597 #include <linux/ww_mutex.h> 598 /* 599 * The torture ww_mutexes should belong to the same lock class as 600 * torture_ww_class to avoid lockdep problem. The ww_mutex_init() 601 * function is called for initialization to ensure that. 602 */ 603 static DEFINE_WD_CLASS(torture_ww_class); 604 static struct ww_mutex torture_ww_mutex_0, torture_ww_mutex_1, torture_ww_mutex_2; 605 static struct ww_acquire_ctx *ww_acquire_ctxs; 606 607 static void torture_ww_mutex_init(void) 608 { 609 ww_mutex_init(&torture_ww_mutex_0, &torture_ww_class); 610 ww_mutex_init(&torture_ww_mutex_1, &torture_ww_class); 611 ww_mutex_init(&torture_ww_mutex_2, &torture_ww_class); 612 613 ww_acquire_ctxs = kmalloc_objs(*ww_acquire_ctxs, 614 cxt.nrealwriters_stress, GFP_KERNEL); 615 if (!ww_acquire_ctxs) 616 VERBOSE_TOROUT_STRING("ww_acquire_ctx: Out of memory"); 617 } 618 619 static void torture_ww_mutex_exit(void) 620 { 621 kfree(ww_acquire_ctxs); 622 } 623 624 static int torture_ww_mutex_lock(int tid) 625 __acquires(torture_ww_mutex_0) 626 __acquires(torture_ww_mutex_1) 627 __acquires(torture_ww_mutex_2) 628 { 629 LIST_HEAD(list); 630 struct reorder_lock { 631 struct list_head link; 632 struct ww_mutex *lock; 633 } locks[3], *ll, *ln; 634 struct ww_acquire_ctx *ctx = &ww_acquire_ctxs[tid]; 635 636 locks[0].lock = &torture_ww_mutex_0; 637 list_add(&locks[0].link, &list); 638 639 locks[1].lock = &torture_ww_mutex_1; 640 list_add(&locks[1].link, &list); 641 642 locks[2].lock = &torture_ww_mutex_2; 643 list_add(&locks[2].link, &list); 644 645 ww_acquire_init(ctx, &torture_ww_class); 646 647 list_for_each_entry(ll, &list, link) { 648 int err; 649 650 err = ww_mutex_lock(ll->lock, ctx); 651 if (!err) 652 continue; 653 654 ln = ll; 655 list_for_each_entry_continue_reverse(ln, &list, link) 656 ww_mutex_unlock(ln->lock); 657 658 if (err != -EDEADLK) 659 return err; 660 661 ww_mutex_lock_slow(ll->lock, ctx); 662 list_move(&ll->link, &list); 663 } 664 665 return 0; 666 } 667 668 static void torture_ww_mutex_unlock(int tid) 669 __releases(torture_ww_mutex_0) 670 __releases(torture_ww_mutex_1) 671 __releases(torture_ww_mutex_2) 672 { 673 struct ww_acquire_ctx *ctx = &ww_acquire_ctxs[tid]; 674 675 ww_mutex_unlock(&torture_ww_mutex_0); 676 ww_mutex_unlock(&torture_ww_mutex_1); 677 ww_mutex_unlock(&torture_ww_mutex_2); 678 ww_acquire_fini(ctx); 679 } 680 681 static struct lock_torture_ops ww_mutex_lock_ops = { 682 .init = torture_ww_mutex_init, 683 .exit = torture_ww_mutex_exit, 684 .writelock = torture_ww_mutex_lock, 685 .write_delay = torture_mutex_delay, 686 .task_boost = torture_rt_boost, 687 .writeunlock = torture_ww_mutex_unlock, 688 .readlock = NULL, 689 .read_delay = NULL, 690 .readunlock = NULL, 691 .name = "ww_mutex_lock" 692 }; 693 694 #ifdef CONFIG_RT_MUTEXES 695 static DEFINE_RT_MUTEX(torture_rtmutex); 696 static struct rt_mutex torture_nested_rtmutexes[MAX_NESTED_LOCKS]; 697 static struct lock_class_key nested_rtmutex_keys[MAX_NESTED_LOCKS]; 698 699 static void torture_rtmutex_init(void) 700 { 701 int i; 702 703 for (i = 0; i < MAX_NESTED_LOCKS; i++) 704 __rt_mutex_init(&torture_nested_rtmutexes[i], __func__, 705 &nested_rtmutex_keys[i]); 706 } 707 708 static int torture_rtmutex_nested_lock(int tid __maybe_unused, 709 u32 lockset) 710 { 711 int i; 712 713 for (i = 0; i < nested_locks; i++) 714 if (lockset & (1 << i)) 715 rt_mutex_lock(&torture_nested_rtmutexes[i]); 716 return 0; 717 } 718 719 static int torture_rtmutex_lock(int tid __maybe_unused) 720 __acquires(torture_rtmutex) 721 { 722 rt_mutex_lock(&torture_rtmutex); 723 return 0; 724 } 725 726 static void torture_rtmutex_delay(struct torture_random_state *trsp) 727 { 728 const unsigned long shortdelay_us = 2; 729 730 /* 731 * We want a short delay mostly to emulate likely code, and 732 * we want a long delay occasionally to force massive contention. 733 */ 734 if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold))) 735 mdelay(long_hold); 736 if (!(torture_random(trsp) % 737 (cxt.nrealwriters_stress * 200 * shortdelay_us))) 738 udelay(shortdelay_us); 739 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000))) 740 torture_preempt_schedule(); /* Allow test to be preempted. */ 741 } 742 743 static void torture_rtmutex_unlock(int tid __maybe_unused) 744 __releases(torture_rtmutex) 745 { 746 rt_mutex_unlock(&torture_rtmutex); 747 } 748 749 static void torture_rt_boost_rtmutex(struct torture_random_state *trsp) 750 { 751 if (!rt_boost) 752 return; 753 754 __torture_rt_boost(trsp); 755 } 756 757 static void torture_rtmutex_nested_unlock(int tid __maybe_unused, 758 u32 lockset) 759 { 760 int i; 761 762 for (i = nested_locks - 1; i >= 0; i--) 763 if (lockset & (1 << i)) 764 rt_mutex_unlock(&torture_nested_rtmutexes[i]); 765 } 766 767 static struct lock_torture_ops rtmutex_lock_ops = { 768 .init = torture_rtmutex_init, 769 .nested_lock = torture_rtmutex_nested_lock, 770 .writelock = torture_rtmutex_lock, 771 .write_delay = torture_rtmutex_delay, 772 .task_boost = torture_rt_boost_rtmutex, 773 .writeunlock = torture_rtmutex_unlock, 774 .nested_unlock = torture_rtmutex_nested_unlock, 775 .readlock = NULL, 776 .read_delay = NULL, 777 .readunlock = NULL, 778 .name = "rtmutex_lock" 779 }; 780 #endif 781 782 static DECLARE_RWSEM(torture_rwsem); 783 static int torture_rwsem_down_write(int tid __maybe_unused) 784 __acquires(torture_rwsem) 785 { 786 down_write(&torture_rwsem); 787 return 0; 788 } 789 790 static void torture_rwsem_write_delay(struct torture_random_state *trsp) 791 { 792 /* We want a long delay occasionally to force massive contention. */ 793 if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold))) 794 mdelay(long_hold * 10); 795 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000))) 796 torture_preempt_schedule(); /* Allow test to be preempted. */ 797 } 798 799 static void torture_rwsem_up_write(int tid __maybe_unused) 800 __releases(torture_rwsem) 801 { 802 up_write(&torture_rwsem); 803 } 804 805 static int torture_rwsem_down_read(int tid __maybe_unused) 806 __acquires(torture_rwsem) 807 { 808 down_read(&torture_rwsem); 809 return 0; 810 } 811 812 static void torture_rwsem_read_delay(struct torture_random_state *trsp) 813 { 814 /* We want a long delay occasionally to force massive contention. */ 815 if (long_hold && !(torture_random(trsp) % (cxt.nrealreaders_stress * 2000 * long_hold))) 816 mdelay(long_hold * 2); 817 else 818 mdelay(long_hold / 2); 819 if (!(torture_random(trsp) % (cxt.nrealreaders_stress * 20000))) 820 torture_preempt_schedule(); /* Allow test to be preempted. */ 821 } 822 823 static void torture_rwsem_up_read(int tid __maybe_unused) 824 __releases(torture_rwsem) 825 { 826 up_read(&torture_rwsem); 827 } 828 829 static struct lock_torture_ops rwsem_lock_ops = { 830 .writelock = torture_rwsem_down_write, 831 .write_delay = torture_rwsem_write_delay, 832 .task_boost = torture_rt_boost, 833 .writeunlock = torture_rwsem_up_write, 834 .readlock = torture_rwsem_down_read, 835 .read_delay = torture_rwsem_read_delay, 836 .readunlock = torture_rwsem_up_read, 837 .name = "rwsem_lock" 838 }; 839 840 #include <linux/percpu-rwsem.h> 841 static struct percpu_rw_semaphore pcpu_rwsem; 842 843 static void torture_percpu_rwsem_init(void) 844 { 845 BUG_ON(percpu_init_rwsem(&pcpu_rwsem)); 846 } 847 848 static void torture_percpu_rwsem_exit(void) 849 { 850 percpu_free_rwsem(&pcpu_rwsem); 851 } 852 853 static int torture_percpu_rwsem_down_write(int tid __maybe_unused) 854 __acquires(pcpu_rwsem) 855 { 856 percpu_down_write(&pcpu_rwsem); 857 return 0; 858 } 859 860 static void torture_percpu_rwsem_up_write(int tid __maybe_unused) 861 __releases(pcpu_rwsem) 862 { 863 percpu_up_write(&pcpu_rwsem); 864 } 865 866 static int torture_percpu_rwsem_down_read(int tid __maybe_unused) 867 __acquires(pcpu_rwsem) 868 { 869 percpu_down_read(&pcpu_rwsem); 870 return 0; 871 } 872 873 static void torture_percpu_rwsem_up_read(int tid __maybe_unused) 874 __releases(pcpu_rwsem) 875 { 876 percpu_up_read(&pcpu_rwsem); 877 } 878 879 static struct lock_torture_ops percpu_rwsem_lock_ops = { 880 .init = torture_percpu_rwsem_init, 881 .exit = torture_percpu_rwsem_exit, 882 .writelock = torture_percpu_rwsem_down_write, 883 .write_delay = torture_rwsem_write_delay, 884 .task_boost = torture_rt_boost, 885 .writeunlock = torture_percpu_rwsem_up_write, 886 .readlock = torture_percpu_rwsem_down_read, 887 .read_delay = torture_rwsem_read_delay, 888 .readunlock = torture_percpu_rwsem_up_read, 889 .name = "percpu_rwsem_lock" 890 }; 891 892 /* 893 * Lock torture writer kthread. Repeatedly acquires and releases 894 * the lock, checking for duplicate acquisitions. 895 */ 896 static int lock_torture_writer(void *arg) 897 { 898 unsigned long j; 899 unsigned long j1; 900 u32 lockset_mask; 901 struct lock_stress_stats *lwsp = arg; 902 DEFINE_TORTURE_RANDOM(rand); 903 bool skip_main_lock; 904 int tid = lwsp - cxt.lwsa; 905 906 VERBOSE_TOROUT_STRING("lock_torture_writer task started"); 907 if (!rt_task(current)) 908 set_user_nice(current, MAX_NICE); 909 910 do { 911 if ((torture_random(&rand) & 0xfffff) == 0) 912 schedule_timeout_uninterruptible(1); 913 914 lockset_mask = torture_random(&rand); 915 /* 916 * When using nested_locks, we want to occasionally 917 * skip the main lock so we can avoid always serializing 918 * the lock chains on that central lock. By skipping the 919 * main lock occasionally, we can create different 920 * contention patterns (allowing for multiple disjoint 921 * blocked trees) 922 */ 923 skip_main_lock = (nested_locks && 924 !(torture_random(&rand) % 100)); 925 926 cxt.cur_ops->task_boost(&rand); 927 if (cxt.cur_ops->nested_lock) 928 cxt.cur_ops->nested_lock(tid, lockset_mask); 929 930 if (!skip_main_lock) { 931 if (acq_writer_lim > 0) 932 j = jiffies; 933 cxt.cur_ops->writelock(tid); 934 if (WARN_ON_ONCE(lock_is_write_held)) 935 lwsp->n_lock_fail++; 936 lock_is_write_held = true; 937 if (WARN_ON_ONCE(atomic_read(&lock_is_read_held))) 938 lwsp->n_lock_fail++; /* rare, but... */ 939 if (acq_writer_lim > 0) { 940 j1 = jiffies; 941 WARN_ONCE(time_after(j1, j + acq_writer_lim), 942 "%s: Lock acquisition took %lu jiffies.\n", 943 __func__, j1 - j); 944 } 945 lwsp->n_lock_acquired++; 946 947 cxt.cur_ops->write_delay(&rand); 948 949 lock_is_write_held = false; 950 WRITE_ONCE(last_lock_release, jiffies); 951 cxt.cur_ops->writeunlock(tid); 952 } 953 if (cxt.cur_ops->nested_unlock) 954 cxt.cur_ops->nested_unlock(tid, lockset_mask); 955 956 stutter_wait("lock_torture_writer"); 957 } while (!torture_must_stop()); 958 959 cxt.cur_ops->task_boost(NULL); /* reset prio */ 960 torture_kthread_stopping("lock_torture_writer"); 961 return 0; 962 } 963 964 /* 965 * Lock torture reader kthread. Repeatedly acquires and releases 966 * the reader lock. 967 */ 968 static int lock_torture_reader(void *arg) 969 { 970 struct lock_stress_stats *lrsp = arg; 971 int tid = lrsp - cxt.lrsa; 972 DEFINE_TORTURE_RANDOM(rand); 973 974 VERBOSE_TOROUT_STRING("lock_torture_reader task started"); 975 set_user_nice(current, MAX_NICE); 976 977 do { 978 if ((torture_random(&rand) & 0xfffff) == 0) 979 schedule_timeout_uninterruptible(1); 980 981 cxt.cur_ops->readlock(tid); 982 atomic_inc(&lock_is_read_held); 983 if (WARN_ON_ONCE(lock_is_write_held)) 984 lrsp->n_lock_fail++; /* rare, but... */ 985 986 lrsp->n_lock_acquired++; 987 cxt.cur_ops->read_delay(&rand); 988 atomic_dec(&lock_is_read_held); 989 cxt.cur_ops->readunlock(tid); 990 991 stutter_wait("lock_torture_reader"); 992 } while (!torture_must_stop()); 993 torture_kthread_stopping("lock_torture_reader"); 994 return 0; 995 } 996 997 /* 998 * Create an lock-torture-statistics message in the specified buffer. 999 */ 1000 static void __torture_print_stats(char *page, 1001 struct lock_stress_stats *statp, bool write) 1002 { 1003 long cur; 1004 bool fail = false; 1005 int i, n_stress; 1006 long max = 0, min = statp ? data_race(statp[0].n_lock_acquired) : 0; 1007 long long sum = 0; 1008 1009 n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress; 1010 for (i = 0; i < n_stress; i++) { 1011 if (data_race(statp[i].n_lock_fail)) 1012 fail = true; 1013 cur = data_race(statp[i].n_lock_acquired); 1014 sum += cur; 1015 if (max < cur) 1016 max = cur; 1017 if (min > cur) 1018 min = cur; 1019 } 1020 page += sprintf(page, 1021 "%s: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n", 1022 write ? "Writes" : "Reads ", 1023 sum, max, min, 1024 !onoff_interval && max / 2 > min ? "???" : "", 1025 fail, fail ? "!!!" : ""); 1026 if (fail) 1027 atomic_inc(&cxt.n_lock_torture_errors); 1028 } 1029 1030 /* 1031 * Print torture statistics. Caller must ensure that there is only one 1032 * call to this function at a given time!!! This is normally accomplished 1033 * by relying on the module system to only have one copy of the module 1034 * loaded, and then by giving the lock_torture_stats kthread full control 1035 * (or the init/cleanup functions when lock_torture_stats thread is not 1036 * running). 1037 */ 1038 static void lock_torture_stats_print(void) 1039 { 1040 int size = cxt.nrealwriters_stress * 200 + 8192; 1041 char *buf; 1042 1043 if (cxt.cur_ops->readlock) 1044 size += cxt.nrealreaders_stress * 200 + 8192; 1045 1046 buf = kmalloc(size, GFP_KERNEL); 1047 if (!buf) { 1048 pr_err("lock_torture_stats_print: Out of memory, need: %d", 1049 size); 1050 return; 1051 } 1052 1053 __torture_print_stats(buf, cxt.lwsa, true); 1054 pr_alert("%s", buf); 1055 kfree(buf); 1056 1057 if (cxt.cur_ops->readlock) { 1058 buf = kmalloc(size, GFP_KERNEL); 1059 if (!buf) { 1060 pr_err("lock_torture_stats_print: Out of memory, need: %d", 1061 size); 1062 return; 1063 } 1064 1065 __torture_print_stats(buf, cxt.lrsa, false); 1066 pr_alert("%s", buf); 1067 kfree(buf); 1068 } 1069 } 1070 1071 /* 1072 * Periodically prints torture statistics, if periodic statistics printing 1073 * was specified via the stat_interval module parameter. 1074 * 1075 * No need to worry about fullstop here, since this one doesn't reference 1076 * volatile state or register callbacks. 1077 */ 1078 static int lock_torture_stats(void *arg) 1079 { 1080 VERBOSE_TOROUT_STRING("lock_torture_stats task started"); 1081 do { 1082 schedule_timeout_interruptible(stat_interval * HZ); 1083 lock_torture_stats_print(); 1084 torture_shutdown_absorb("lock_torture_stats"); 1085 } while (!torture_must_stop()); 1086 torture_kthread_stopping("lock_torture_stats"); 1087 return 0; 1088 } 1089 1090 1091 static inline void 1092 lock_torture_print_module_parms(struct lock_torture_ops *cur_ops, 1093 const char *tag) 1094 { 1095 static cpumask_t cpumask_all; 1096 cpumask_t *rcmp = cpumask_nonempty(bind_readers) ? bind_readers : &cpumask_all; 1097 cpumask_t *wcmp = cpumask_nonempty(bind_writers) ? bind_writers : &cpumask_all; 1098 1099 cpumask_setall(&cpumask_all); 1100 pr_alert("%s" TORTURE_FLAG 1101 "--- %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", 1102 torture_type, tag, cxt.debug_lock ? " [debug]": "", 1103 acq_writer_lim, cpumask_pr_args(rcmp), cpumask_pr_args(wcmp), 1104 call_rcu_chains, long_hold, nested_locks, cxt.nrealreaders_stress, 1105 cxt.nrealwriters_stress, onoff_holdoff, onoff_interval, rt_boost, 1106 rt_boost_factor, shuffle_interval, shutdown_secs, stat_interval, stutter, 1107 verbose, writer_fifo); 1108 } 1109 1110 // If requested, maintain call_rcu() chains to keep a grace period always 1111 // in flight. These increase the probability of getting an RCU CPU stall 1112 // warning and associated diagnostics when a locking primitive stalls. 1113 1114 static void call_rcu_chain_cb(struct rcu_head *rhp) 1115 { 1116 struct call_rcu_chain *crcp = container_of(rhp, struct call_rcu_chain, crc_rh); 1117 1118 if (!smp_load_acquire(&crcp->crc_stop)) { 1119 (void)start_poll_synchronize_rcu(); // Start one grace period... 1120 call_rcu(&crcp->crc_rh, call_rcu_chain_cb); // ... and later start another. 1121 } 1122 } 1123 1124 // Start the requested number of call_rcu() chains. 1125 static int call_rcu_chain_init(void) 1126 { 1127 int i; 1128 1129 if (call_rcu_chains <= 0) 1130 return 0; 1131 call_rcu_chain_list = kzalloc_objs(*call_rcu_chain_list, 1132 call_rcu_chains, GFP_KERNEL); 1133 if (!call_rcu_chain_list) 1134 return -ENOMEM; 1135 for (i = 0; i < call_rcu_chains; i++) { 1136 call_rcu_chain_list[i].crc_stop = false; 1137 call_rcu(&call_rcu_chain_list[i].crc_rh, call_rcu_chain_cb); 1138 } 1139 return 0; 1140 } 1141 1142 // Stop all of the call_rcu() chains. 1143 static void call_rcu_chain_cleanup(void) 1144 { 1145 int i; 1146 1147 if (!call_rcu_chain_list) 1148 return; 1149 for (i = 0; i < call_rcu_chains; i++) 1150 smp_store_release(&call_rcu_chain_list[i].crc_stop, true); 1151 rcu_barrier(); 1152 kfree(call_rcu_chain_list); 1153 call_rcu_chain_list = NULL; 1154 } 1155 1156 static void lock_torture_cleanup(void) 1157 { 1158 int i; 1159 1160 if (torture_cleanup_begin()) 1161 return; 1162 1163 /* 1164 * Indicates early cleanup, meaning that the test has not run, 1165 * such as when passing bogus args when loading the module. 1166 * However cxt->cur_ops.init() may have been invoked, so beside 1167 * perform the underlying torture-specific cleanups, cur_ops.exit() 1168 * will be invoked if needed. 1169 */ 1170 if (!cxt.lwsa && !cxt.lrsa) 1171 goto end; 1172 1173 if (writer_tasks) { 1174 for (i = 0; i < cxt.nrealwriters_stress; i++) 1175 torture_stop_kthread(lock_torture_writer, writer_tasks[i]); 1176 kfree(writer_tasks); 1177 writer_tasks = NULL; 1178 } 1179 1180 if (reader_tasks) { 1181 for (i = 0; i < cxt.nrealreaders_stress; i++) 1182 torture_stop_kthread(lock_torture_reader, 1183 reader_tasks[i]); 1184 kfree(reader_tasks); 1185 reader_tasks = NULL; 1186 } 1187 1188 torture_stop_kthread(lock_torture_stats, stats_task); 1189 lock_torture_stats_print(); /* -After- the stats thread is stopped! */ 1190 1191 if (atomic_read(&cxt.n_lock_torture_errors)) 1192 lock_torture_print_module_parms(cxt.cur_ops, 1193 "End of test: FAILURE"); 1194 else if (torture_onoff_failures()) 1195 lock_torture_print_module_parms(cxt.cur_ops, 1196 "End of test: LOCK_HOTPLUG"); 1197 else 1198 lock_torture_print_module_parms(cxt.cur_ops, 1199 "End of test: SUCCESS"); 1200 1201 kfree(cxt.lwsa); 1202 cxt.lwsa = NULL; 1203 kfree(cxt.lrsa); 1204 cxt.lrsa = NULL; 1205 1206 call_rcu_chain_cleanup(); 1207 1208 end: 1209 if (cxt.init_called) { 1210 if (cxt.cur_ops->exit) 1211 cxt.cur_ops->exit(); 1212 cxt.init_called = false; 1213 } 1214 1215 free_cpumask_var(bind_readers); 1216 free_cpumask_var(bind_writers); 1217 1218 torture_cleanup_end(); 1219 } 1220 1221 static int __init lock_torture_init(void) 1222 { 1223 int i, j; 1224 int firsterr = 0; 1225 static struct lock_torture_ops *torture_ops[] = { 1226 &lock_busted_ops, 1227 &spin_lock_ops, &spin_lock_irq_ops, 1228 &raw_spin_lock_ops, &raw_spin_lock_irq_ops, 1229 #ifdef CONFIG_BPF_SYSCALL 1230 &raw_res_spin_lock_ops, &raw_res_spin_lock_irq_ops, 1231 #endif 1232 &rw_lock_ops, &rw_lock_irq_ops, 1233 &mutex_lock_ops, 1234 &ww_mutex_lock_ops, 1235 #ifdef CONFIG_RT_MUTEXES 1236 &rtmutex_lock_ops, 1237 #endif 1238 &rwsem_lock_ops, 1239 &percpu_rwsem_lock_ops, 1240 }; 1241 1242 if (!torture_init_begin(torture_type, verbose)) 1243 return -EBUSY; 1244 1245 /* Process args and tell the world that the torturer is on the job. */ 1246 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) { 1247 cxt.cur_ops = torture_ops[i]; 1248 if (strcmp(torture_type, cxt.cur_ops->name) == 0) 1249 break; 1250 } 1251 if (i == ARRAY_SIZE(torture_ops)) { 1252 pr_alert("lock-torture: invalid torture type: \"%s\"\n", 1253 torture_type); 1254 pr_alert("lock-torture types:"); 1255 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) 1256 pr_alert(" %s", torture_ops[i]->name); 1257 pr_alert("\n"); 1258 firsterr = -EINVAL; 1259 goto unwind; 1260 } 1261 1262 if (nwriters_stress == 0 && 1263 (!cxt.cur_ops->readlock || nreaders_stress == 0)) { 1264 pr_alert("lock-torture: must run at least one locking thread\n"); 1265 firsterr = -EINVAL; 1266 goto unwind; 1267 } 1268 1269 if (nwriters_stress >= 0) 1270 cxt.nrealwriters_stress = nwriters_stress; 1271 else 1272 cxt.nrealwriters_stress = 2 * num_online_cpus(); 1273 1274 if (cxt.cur_ops->init) { 1275 cxt.cur_ops->init(); 1276 cxt.init_called = true; 1277 } 1278 1279 #ifdef CONFIG_DEBUG_MUTEXES 1280 if (str_has_prefix(torture_type, "mutex")) 1281 cxt.debug_lock = true; 1282 #endif 1283 #ifdef CONFIG_DEBUG_RT_MUTEXES 1284 if (str_has_prefix(torture_type, "rtmutex")) 1285 cxt.debug_lock = true; 1286 #endif 1287 #ifdef CONFIG_DEBUG_SPINLOCK 1288 if ((str_has_prefix(torture_type, "spin")) || 1289 (str_has_prefix(torture_type, "rw_lock"))) 1290 cxt.debug_lock = true; 1291 #endif 1292 1293 /* Initialize the statistics so that each run gets its own numbers. */ 1294 if (nwriters_stress) { 1295 lock_is_write_held = false; 1296 cxt.lwsa = kmalloc_objs(*cxt.lwsa, cxt.nrealwriters_stress, 1297 GFP_KERNEL); 1298 if (cxt.lwsa == NULL) { 1299 VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory"); 1300 firsterr = -ENOMEM; 1301 goto unwind; 1302 } 1303 1304 for (i = 0; i < cxt.nrealwriters_stress; i++) { 1305 cxt.lwsa[i].n_lock_fail = 0; 1306 cxt.lwsa[i].n_lock_acquired = 0; 1307 } 1308 } 1309 1310 if (cxt.cur_ops->readlock) { 1311 if (nreaders_stress >= 0) 1312 cxt.nrealreaders_stress = nreaders_stress; 1313 else { 1314 /* 1315 * By default distribute evenly the number of 1316 * readers and writers. We still run the same number 1317 * of threads as the writer-only locks default. 1318 */ 1319 if (nwriters_stress < 0) /* user doesn't care */ 1320 cxt.nrealwriters_stress = num_online_cpus(); 1321 cxt.nrealreaders_stress = cxt.nrealwriters_stress; 1322 } 1323 1324 if (nreaders_stress) { 1325 cxt.lrsa = kmalloc_objs(*cxt.lrsa, 1326 cxt.nrealreaders_stress, 1327 GFP_KERNEL); 1328 if (cxt.lrsa == NULL) { 1329 VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory"); 1330 firsterr = -ENOMEM; 1331 kfree(cxt.lwsa); 1332 cxt.lwsa = NULL; 1333 goto unwind; 1334 } 1335 1336 for (i = 0; i < cxt.nrealreaders_stress; i++) { 1337 cxt.lrsa[i].n_lock_fail = 0; 1338 cxt.lrsa[i].n_lock_acquired = 0; 1339 } 1340 } 1341 } 1342 1343 firsterr = call_rcu_chain_init(); 1344 if (torture_init_error(firsterr)) 1345 goto unwind; 1346 1347 lock_torture_print_module_parms(cxt.cur_ops, "Start of test"); 1348 1349 /* Prepare torture context. */ 1350 if (onoff_interval > 0) { 1351 firsterr = torture_onoff_init(onoff_holdoff * HZ, 1352 onoff_interval * HZ, NULL); 1353 if (torture_init_error(firsterr)) 1354 goto unwind; 1355 } 1356 if (shuffle_interval > 0) { 1357 firsterr = torture_shuffle_init(shuffle_interval); 1358 if (torture_init_error(firsterr)) 1359 goto unwind; 1360 } 1361 if (shutdown_secs > 0) { 1362 firsterr = torture_shutdown_init(shutdown_secs, 1363 lock_torture_cleanup); 1364 if (torture_init_error(firsterr)) 1365 goto unwind; 1366 } 1367 if (stutter > 0) { 1368 firsterr = torture_stutter_init(stutter, stutter); 1369 if (torture_init_error(firsterr)) 1370 goto unwind; 1371 } 1372 1373 if (nwriters_stress) { 1374 writer_tasks = kzalloc_objs(writer_tasks[0], 1375 cxt.nrealwriters_stress, GFP_KERNEL); 1376 if (writer_tasks == NULL) { 1377 TOROUT_ERRSTRING("writer_tasks: Out of memory"); 1378 firsterr = -ENOMEM; 1379 goto unwind; 1380 } 1381 } 1382 1383 /* cap nested_locks to MAX_NESTED_LOCKS */ 1384 if (nested_locks > MAX_NESTED_LOCKS) 1385 nested_locks = MAX_NESTED_LOCKS; 1386 1387 if (cxt.cur_ops->readlock) { 1388 reader_tasks = kzalloc_objs(reader_tasks[0], 1389 cxt.nrealreaders_stress, GFP_KERNEL); 1390 if (reader_tasks == NULL) { 1391 TOROUT_ERRSTRING("reader_tasks: Out of memory"); 1392 kfree(writer_tasks); 1393 writer_tasks = NULL; 1394 firsterr = -ENOMEM; 1395 goto unwind; 1396 } 1397 } 1398 1399 /* 1400 * Create the kthreads and start torturing (oh, those poor little locks). 1401 * 1402 * TODO: Note that we interleave writers with readers, giving writers a 1403 * slight advantage, by creating its kthread first. This can be modified 1404 * for very specific needs, or even let the user choose the policy, if 1405 * ever wanted. 1406 */ 1407 for (i = 0, j = 0; i < cxt.nrealwriters_stress || 1408 j < cxt.nrealreaders_stress; i++, j++) { 1409 if (i >= cxt.nrealwriters_stress) 1410 goto create_reader; 1411 1412 /* Create writer. */ 1413 firsterr = torture_create_kthread_cb(lock_torture_writer, &cxt.lwsa[i], 1414 writer_tasks[i], 1415 writer_fifo ? sched_set_fifo : NULL); 1416 if (torture_init_error(firsterr)) 1417 goto unwind; 1418 if (cpumask_nonempty(bind_writers)) 1419 torture_sched_setaffinity(writer_tasks[i]->pid, bind_writers, true); 1420 1421 create_reader: 1422 if (cxt.cur_ops->readlock == NULL || (j >= cxt.nrealreaders_stress)) 1423 continue; 1424 /* Create reader. */ 1425 firsterr = torture_create_kthread(lock_torture_reader, &cxt.lrsa[j], 1426 reader_tasks[j]); 1427 if (torture_init_error(firsterr)) 1428 goto unwind; 1429 if (cpumask_nonempty(bind_readers)) 1430 torture_sched_setaffinity(reader_tasks[j]->pid, bind_readers, true); 1431 } 1432 if (stat_interval > 0) { 1433 firsterr = torture_create_kthread(lock_torture_stats, NULL, 1434 stats_task); 1435 if (torture_init_error(firsterr)) 1436 goto unwind; 1437 } 1438 torture_init_end(); 1439 return 0; 1440 1441 unwind: 1442 torture_init_end(); 1443 lock_torture_cleanup(); 1444 if (shutdown_secs) { 1445 WARN_ON(!IS_MODULE(CONFIG_LOCK_TORTURE_TEST)); 1446 kernel_power_off(); 1447 } 1448 return firsterr; 1449 } 1450 1451 module_init(lock_torture_init); 1452 module_exit(lock_torture_cleanup); 1453