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, 0644);
107 module_param_cb(bind_writers, <_bind_ops, &bind_writers, 0644);
108
109 long torture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask);
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 static DEFINE_RWLOCK(torture_rwlock);
366
367 static int torture_rwlock_write_lock(int tid __maybe_unused)
368 __acquires(torture_rwlock)
369 {
370 write_lock(&torture_rwlock);
371 return 0;
372 }
373
374 static void torture_rwlock_write_delay(struct torture_random_state *trsp)
375 {
376 const unsigned long shortdelay_us = 2;
377
378 /* We want a short delay mostly to emulate likely code, and
379 * we want a long delay occasionally to force massive contention.
380 */
381 if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold)))
382 mdelay(long_hold);
383 else
384 udelay(shortdelay_us);
385 }
386
387 static void torture_rwlock_write_unlock(int tid __maybe_unused)
388 __releases(torture_rwlock)
389 {
390 write_unlock(&torture_rwlock);
391 }
392
393 static int torture_rwlock_read_lock(int tid __maybe_unused)
394 __acquires(torture_rwlock)
395 {
396 read_lock(&torture_rwlock);
397 return 0;
398 }
399
400 static void torture_rwlock_read_delay(struct torture_random_state *trsp)
401 {
402 const unsigned long shortdelay_us = 10;
403
404 /* We want a short delay mostly to emulate likely code, and
405 * we want a long delay occasionally to force massive contention.
406 */
407 if (long_hold && !(torture_random(trsp) % (cxt.nrealreaders_stress * 2000 * long_hold)))
408 mdelay(long_hold);
409 else
410 udelay(shortdelay_us);
411 }
412
413 static void torture_rwlock_read_unlock(int tid __maybe_unused)
414 __releases(torture_rwlock)
415 {
416 read_unlock(&torture_rwlock);
417 }
418
419 static struct lock_torture_ops rw_lock_ops = {
420 .writelock = torture_rwlock_write_lock,
421 .write_delay = torture_rwlock_write_delay,
422 .task_boost = torture_rt_boost,
423 .writeunlock = torture_rwlock_write_unlock,
424 .readlock = torture_rwlock_read_lock,
425 .read_delay = torture_rwlock_read_delay,
426 .readunlock = torture_rwlock_read_unlock,
427 .name = "rw_lock"
428 };
429
430 static int torture_rwlock_write_lock_irq(int tid __maybe_unused)
431 __acquires(torture_rwlock)
432 {
433 unsigned long flags;
434
435 write_lock_irqsave(&torture_rwlock, flags);
436 cxt.cur_ops->flags = flags;
437 return 0;
438 }
439
440 static void torture_rwlock_write_unlock_irq(int tid __maybe_unused)
441 __releases(torture_rwlock)
442 {
443 write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
444 }
445
446 static int torture_rwlock_read_lock_irq(int tid __maybe_unused)
447 __acquires(torture_rwlock)
448 {
449 unsigned long flags;
450
451 read_lock_irqsave(&torture_rwlock, flags);
452 cxt.cur_ops->flags = flags;
453 return 0;
454 }
455
456 static void torture_rwlock_read_unlock_irq(int tid __maybe_unused)
457 __releases(torture_rwlock)
458 {
459 read_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
460 }
461
462 static struct lock_torture_ops rw_lock_irq_ops = {
463 .writelock = torture_rwlock_write_lock_irq,
464 .write_delay = torture_rwlock_write_delay,
465 .task_boost = torture_rt_boost,
466 .writeunlock = torture_rwlock_write_unlock_irq,
467 .readlock = torture_rwlock_read_lock_irq,
468 .read_delay = torture_rwlock_read_delay,
469 .readunlock = torture_rwlock_read_unlock_irq,
470 .name = "rw_lock_irq"
471 };
472
473 static DEFINE_MUTEX(torture_mutex);
474 static struct mutex torture_nested_mutexes[MAX_NESTED_LOCKS];
475 static struct lock_class_key nested_mutex_keys[MAX_NESTED_LOCKS];
476
477 static void torture_mutex_init(void)
478 {
479 int i;
480
481 for (i = 0; i < MAX_NESTED_LOCKS; i++)
482 __mutex_init(&torture_nested_mutexes[i], __func__,
483 &nested_mutex_keys[i]);
484 }
485
486 static int torture_mutex_nested_lock(int tid __maybe_unused,
487 u32 lockset)
488 {
489 int i;
490
491 for (i = 0; i < nested_locks; i++)
492 if (lockset & (1 << i))
493 mutex_lock(&torture_nested_mutexes[i]);
494 return 0;
495 }
496
497 static int torture_mutex_lock(int tid __maybe_unused)
498 __acquires(torture_mutex)
499 {
500 mutex_lock(&torture_mutex);
501 return 0;
502 }
503
504 static void torture_mutex_delay(struct torture_random_state *trsp)
505 {
506 /* We want a long delay occasionally to force massive contention. */
507 if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold)))
508 mdelay(long_hold * 5);
509 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
510 torture_preempt_schedule(); /* Allow test to be preempted. */
511 }
512
513 static void torture_mutex_unlock(int tid __maybe_unused)
514 __releases(torture_mutex)
515 {
516 mutex_unlock(&torture_mutex);
517 }
518
519 static void torture_mutex_nested_unlock(int tid __maybe_unused,
520 u32 lockset)
521 {
522 int i;
523
524 for (i = nested_locks - 1; i >= 0; i--)
525 if (lockset & (1 << i))
526 mutex_unlock(&torture_nested_mutexes[i]);
527 }
528
529 static struct lock_torture_ops mutex_lock_ops = {
530 .init = torture_mutex_init,
531 .nested_lock = torture_mutex_nested_lock,
532 .writelock = torture_mutex_lock,
533 .write_delay = torture_mutex_delay,
534 .task_boost = torture_rt_boost,
535 .writeunlock = torture_mutex_unlock,
536 .nested_unlock = torture_mutex_nested_unlock,
537 .readlock = NULL,
538 .read_delay = NULL,
539 .readunlock = NULL,
540 .name = "mutex_lock"
541 };
542
543 #include <linux/ww_mutex.h>
544 /*
545 * The torture ww_mutexes should belong to the same lock class as
546 * torture_ww_class to avoid lockdep problem. The ww_mutex_init()
547 * function is called for initialization to ensure that.
548 */
549 static DEFINE_WD_CLASS(torture_ww_class);
550 static struct ww_mutex torture_ww_mutex_0, torture_ww_mutex_1, torture_ww_mutex_2;
551 static struct ww_acquire_ctx *ww_acquire_ctxs;
552
553 static void torture_ww_mutex_init(void)
554 {
555 ww_mutex_init(&torture_ww_mutex_0, &torture_ww_class);
556 ww_mutex_init(&torture_ww_mutex_1, &torture_ww_class);
557 ww_mutex_init(&torture_ww_mutex_2, &torture_ww_class);
558
559 ww_acquire_ctxs = kmalloc_array(cxt.nrealwriters_stress,
560 sizeof(*ww_acquire_ctxs),
561 GFP_KERNEL);
562 if (!ww_acquire_ctxs)
563 VERBOSE_TOROUT_STRING("ww_acquire_ctx: Out of memory");
564 }
565
566 static void torture_ww_mutex_exit(void)
567 {
568 kfree(ww_acquire_ctxs);
569 }
570
571 static int torture_ww_mutex_lock(int tid)
572 __acquires(torture_ww_mutex_0)
573 __acquires(torture_ww_mutex_1)
574 __acquires(torture_ww_mutex_2)
575 {
576 LIST_HEAD(list);
577 struct reorder_lock {
578 struct list_head link;
579 struct ww_mutex *lock;
580 } locks[3], *ll, *ln;
581 struct ww_acquire_ctx *ctx = &ww_acquire_ctxs[tid];
582
583 locks[0].lock = &torture_ww_mutex_0;
584 list_add(&locks[0].link, &list);
585
586 locks[1].lock = &torture_ww_mutex_1;
587 list_add(&locks[1].link, &list);
588
589 locks[2].lock = &torture_ww_mutex_2;
590 list_add(&locks[2].link, &list);
591
592 ww_acquire_init(ctx, &torture_ww_class);
593
594 list_for_each_entry(ll, &list, link) {
595 int err;
596
597 err = ww_mutex_lock(ll->lock, ctx);
598 if (!err)
599 continue;
600
601 ln = ll;
602 list_for_each_entry_continue_reverse(ln, &list, link)
603 ww_mutex_unlock(ln->lock);
604
605 if (err != -EDEADLK)
606 return err;
607
608 ww_mutex_lock_slow(ll->lock, ctx);
609 list_move(&ll->link, &list);
610 }
611
612 return 0;
613 }
614
615 static void torture_ww_mutex_unlock(int tid)
616 __releases(torture_ww_mutex_0)
617 __releases(torture_ww_mutex_1)
618 __releases(torture_ww_mutex_2)
619 {
620 struct ww_acquire_ctx *ctx = &ww_acquire_ctxs[tid];
621
622 ww_mutex_unlock(&torture_ww_mutex_0);
623 ww_mutex_unlock(&torture_ww_mutex_1);
624 ww_mutex_unlock(&torture_ww_mutex_2);
625 ww_acquire_fini(ctx);
626 }
627
628 static struct lock_torture_ops ww_mutex_lock_ops = {
629 .init = torture_ww_mutex_init,
630 .exit = torture_ww_mutex_exit,
631 .writelock = torture_ww_mutex_lock,
632 .write_delay = torture_mutex_delay,
633 .task_boost = torture_rt_boost,
634 .writeunlock = torture_ww_mutex_unlock,
635 .readlock = NULL,
636 .read_delay = NULL,
637 .readunlock = NULL,
638 .name = "ww_mutex_lock"
639 };
640
641 #ifdef CONFIG_RT_MUTEXES
642 static DEFINE_RT_MUTEX(torture_rtmutex);
643 static struct rt_mutex torture_nested_rtmutexes[MAX_NESTED_LOCKS];
644 static struct lock_class_key nested_rtmutex_keys[MAX_NESTED_LOCKS];
645
646 static void torture_rtmutex_init(void)
647 {
648 int i;
649
650 for (i = 0; i < MAX_NESTED_LOCKS; i++)
651 __rt_mutex_init(&torture_nested_rtmutexes[i], __func__,
652 &nested_rtmutex_keys[i]);
653 }
654
655 static int torture_rtmutex_nested_lock(int tid __maybe_unused,
656 u32 lockset)
657 {
658 int i;
659
660 for (i = 0; i < nested_locks; i++)
661 if (lockset & (1 << i))
662 rt_mutex_lock(&torture_nested_rtmutexes[i]);
663 return 0;
664 }
665
666 static int torture_rtmutex_lock(int tid __maybe_unused)
667 __acquires(torture_rtmutex)
668 {
669 rt_mutex_lock(&torture_rtmutex);
670 return 0;
671 }
672
673 static void torture_rtmutex_delay(struct torture_random_state *trsp)
674 {
675 const unsigned long shortdelay_us = 2;
676
677 /*
678 * We want a short delay mostly to emulate likely code, and
679 * we want a long delay occasionally to force massive contention.
680 */
681 if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold)))
682 mdelay(long_hold);
683 if (!(torture_random(trsp) %
684 (cxt.nrealwriters_stress * 200 * shortdelay_us)))
685 udelay(shortdelay_us);
686 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
687 torture_preempt_schedule(); /* Allow test to be preempted. */
688 }
689
690 static void torture_rtmutex_unlock(int tid __maybe_unused)
691 __releases(torture_rtmutex)
692 {
693 rt_mutex_unlock(&torture_rtmutex);
694 }
695
696 static void torture_rt_boost_rtmutex(struct torture_random_state *trsp)
697 {
698 if (!rt_boost)
699 return;
700
701 __torture_rt_boost(trsp);
702 }
703
704 static void torture_rtmutex_nested_unlock(int tid __maybe_unused,
705 u32 lockset)
706 {
707 int i;
708
709 for (i = nested_locks - 1; i >= 0; i--)
710 if (lockset & (1 << i))
711 rt_mutex_unlock(&torture_nested_rtmutexes[i]);
712 }
713
714 static struct lock_torture_ops rtmutex_lock_ops = {
715 .init = torture_rtmutex_init,
716 .nested_lock = torture_rtmutex_nested_lock,
717 .writelock = torture_rtmutex_lock,
718 .write_delay = torture_rtmutex_delay,
719 .task_boost = torture_rt_boost_rtmutex,
720 .writeunlock = torture_rtmutex_unlock,
721 .nested_unlock = torture_rtmutex_nested_unlock,
722 .readlock = NULL,
723 .read_delay = NULL,
724 .readunlock = NULL,
725 .name = "rtmutex_lock"
726 };
727 #endif
728
729 static DECLARE_RWSEM(torture_rwsem);
730 static int torture_rwsem_down_write(int tid __maybe_unused)
731 __acquires(torture_rwsem)
732 {
733 down_write(&torture_rwsem);
734 return 0;
735 }
736
737 static void torture_rwsem_write_delay(struct torture_random_state *trsp)
738 {
739 /* We want a long delay occasionally to force massive contention. */
740 if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold)))
741 mdelay(long_hold * 10);
742 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
743 torture_preempt_schedule(); /* Allow test to be preempted. */
744 }
745
746 static void torture_rwsem_up_write(int tid __maybe_unused)
747 __releases(torture_rwsem)
748 {
749 up_write(&torture_rwsem);
750 }
751
752 static int torture_rwsem_down_read(int tid __maybe_unused)
753 __acquires(torture_rwsem)
754 {
755 down_read(&torture_rwsem);
756 return 0;
757 }
758
759 static void torture_rwsem_read_delay(struct torture_random_state *trsp)
760 {
761 /* We want a long delay occasionally to force massive contention. */
762 if (long_hold && !(torture_random(trsp) % (cxt.nrealreaders_stress * 2000 * long_hold)))
763 mdelay(long_hold * 2);
764 else
765 mdelay(long_hold / 2);
766 if (!(torture_random(trsp) % (cxt.nrealreaders_stress * 20000)))
767 torture_preempt_schedule(); /* Allow test to be preempted. */
768 }
769
770 static void torture_rwsem_up_read(int tid __maybe_unused)
771 __releases(torture_rwsem)
772 {
773 up_read(&torture_rwsem);
774 }
775
776 static struct lock_torture_ops rwsem_lock_ops = {
777 .writelock = torture_rwsem_down_write,
778 .write_delay = torture_rwsem_write_delay,
779 .task_boost = torture_rt_boost,
780 .writeunlock = torture_rwsem_up_write,
781 .readlock = torture_rwsem_down_read,
782 .read_delay = torture_rwsem_read_delay,
783 .readunlock = torture_rwsem_up_read,
784 .name = "rwsem_lock"
785 };
786
787 #include <linux/percpu-rwsem.h>
788 static struct percpu_rw_semaphore pcpu_rwsem;
789
790 static void torture_percpu_rwsem_init(void)
791 {
792 BUG_ON(percpu_init_rwsem(&pcpu_rwsem));
793 }
794
795 static void torture_percpu_rwsem_exit(void)
796 {
797 percpu_free_rwsem(&pcpu_rwsem);
798 }
799
800 static int torture_percpu_rwsem_down_write(int tid __maybe_unused)
801 __acquires(pcpu_rwsem)
802 {
803 percpu_down_write(&pcpu_rwsem);
804 return 0;
805 }
806
807 static void torture_percpu_rwsem_up_write(int tid __maybe_unused)
808 __releases(pcpu_rwsem)
809 {
810 percpu_up_write(&pcpu_rwsem);
811 }
812
813 static int torture_percpu_rwsem_down_read(int tid __maybe_unused)
814 __acquires(pcpu_rwsem)
815 {
816 percpu_down_read(&pcpu_rwsem);
817 return 0;
818 }
819
820 static void torture_percpu_rwsem_up_read(int tid __maybe_unused)
821 __releases(pcpu_rwsem)
822 {
823 percpu_up_read(&pcpu_rwsem);
824 }
825
826 static struct lock_torture_ops percpu_rwsem_lock_ops = {
827 .init = torture_percpu_rwsem_init,
828 .exit = torture_percpu_rwsem_exit,
829 .writelock = torture_percpu_rwsem_down_write,
830 .write_delay = torture_rwsem_write_delay,
831 .task_boost = torture_rt_boost,
832 .writeunlock = torture_percpu_rwsem_up_write,
833 .readlock = torture_percpu_rwsem_down_read,
834 .read_delay = torture_rwsem_read_delay,
835 .readunlock = torture_percpu_rwsem_up_read,
836 .name = "percpu_rwsem_lock"
837 };
838
839 /*
840 * Lock torture writer kthread. Repeatedly acquires and releases
841 * the lock, checking for duplicate acquisitions.
842 */
843 static int lock_torture_writer(void *arg)
844 {
845 unsigned long j;
846 unsigned long j1;
847 u32 lockset_mask;
848 struct lock_stress_stats *lwsp = arg;
849 DEFINE_TORTURE_RANDOM(rand);
850 bool skip_main_lock;
851 int tid = lwsp - cxt.lwsa;
852
853 VERBOSE_TOROUT_STRING("lock_torture_writer task started");
854 if (!rt_task(current))
855 set_user_nice(current, MAX_NICE);
856
857 do {
858 if ((torture_random(&rand) & 0xfffff) == 0)
859 schedule_timeout_uninterruptible(1);
860
861 lockset_mask = torture_random(&rand);
862 /*
863 * When using nested_locks, we want to occasionally
864 * skip the main lock so we can avoid always serializing
865 * the lock chains on that central lock. By skipping the
866 * main lock occasionally, we can create different
867 * contention patterns (allowing for multiple disjoint
868 * blocked trees)
869 */
870 skip_main_lock = (nested_locks &&
871 !(torture_random(&rand) % 100));
872
873 cxt.cur_ops->task_boost(&rand);
874 if (cxt.cur_ops->nested_lock)
875 cxt.cur_ops->nested_lock(tid, lockset_mask);
876
877 if (!skip_main_lock) {
878 if (acq_writer_lim > 0)
879 j = jiffies;
880 cxt.cur_ops->writelock(tid);
881 if (WARN_ON_ONCE(lock_is_write_held))
882 lwsp->n_lock_fail++;
883 lock_is_write_held = true;
884 if (WARN_ON_ONCE(atomic_read(&lock_is_read_held)))
885 lwsp->n_lock_fail++; /* rare, but... */
886 if (acq_writer_lim > 0) {
887 j1 = jiffies;
888 WARN_ONCE(time_after(j1, j + acq_writer_lim),
889 "%s: Lock acquisition took %lu jiffies.\n",
890 __func__, j1 - j);
891 }
892 lwsp->n_lock_acquired++;
893
894 cxt.cur_ops->write_delay(&rand);
895
896 lock_is_write_held = false;
897 WRITE_ONCE(last_lock_release, jiffies);
898 cxt.cur_ops->writeunlock(tid);
899 }
900 if (cxt.cur_ops->nested_unlock)
901 cxt.cur_ops->nested_unlock(tid, lockset_mask);
902
903 stutter_wait("lock_torture_writer");
904 } while (!torture_must_stop());
905
906 cxt.cur_ops->task_boost(NULL); /* reset prio */
907 torture_kthread_stopping("lock_torture_writer");
908 return 0;
909 }
910
911 /*
912 * Lock torture reader kthread. Repeatedly acquires and releases
913 * the reader lock.
914 */
915 static int lock_torture_reader(void *arg)
916 {
917 struct lock_stress_stats *lrsp = arg;
918 int tid = lrsp - cxt.lrsa;
919 DEFINE_TORTURE_RANDOM(rand);
920
921 VERBOSE_TOROUT_STRING("lock_torture_reader task started");
922 set_user_nice(current, MAX_NICE);
923
924 do {
925 if ((torture_random(&rand) & 0xfffff) == 0)
926 schedule_timeout_uninterruptible(1);
927
928 cxt.cur_ops->readlock(tid);
929 atomic_inc(&lock_is_read_held);
930 if (WARN_ON_ONCE(lock_is_write_held))
931 lrsp->n_lock_fail++; /* rare, but... */
932
933 lrsp->n_lock_acquired++;
934 cxt.cur_ops->read_delay(&rand);
935 atomic_dec(&lock_is_read_held);
936 cxt.cur_ops->readunlock(tid);
937
938 stutter_wait("lock_torture_reader");
939 } while (!torture_must_stop());
940 torture_kthread_stopping("lock_torture_reader");
941 return 0;
942 }
943
944 /*
945 * Create an lock-torture-statistics message in the specified buffer.
946 */
947 static void __torture_print_stats(char *page,
948 struct lock_stress_stats *statp, bool write)
949 {
950 long cur;
951 bool fail = false;
952 int i, n_stress;
953 long max = 0, min = statp ? data_race(statp[0].n_lock_acquired) : 0;
954 long long sum = 0;
955
956 n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress;
957 for (i = 0; i < n_stress; i++) {
958 if (data_race(statp[i].n_lock_fail))
959 fail = true;
960 cur = data_race(statp[i].n_lock_acquired);
961 sum += cur;
962 if (max < cur)
963 max = cur;
964 if (min > cur)
965 min = cur;
966 }
967 page += sprintf(page,
968 "%s: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n",
969 write ? "Writes" : "Reads ",
970 sum, max, min,
971 !onoff_interval && max / 2 > min ? "???" : "",
972 fail, fail ? "!!!" : "");
973 if (fail)
974 atomic_inc(&cxt.n_lock_torture_errors);
975 }
976
977 /*
978 * Print torture statistics. Caller must ensure that there is only one
979 * call to this function at a given time!!! This is normally accomplished
980 * by relying on the module system to only have one copy of the module
981 * loaded, and then by giving the lock_torture_stats kthread full control
982 * (or the init/cleanup functions when lock_torture_stats thread is not
983 * running).
984 */
985 static void lock_torture_stats_print(void)
986 {
987 int size = cxt.nrealwriters_stress * 200 + 8192;
988 char *buf;
989
990 if (cxt.cur_ops->readlock)
991 size += cxt.nrealreaders_stress * 200 + 8192;
992
993 buf = kmalloc(size, GFP_KERNEL);
994 if (!buf) {
995 pr_err("lock_torture_stats_print: Out of memory, need: %d",
996 size);
997 return;
998 }
999
1000 __torture_print_stats(buf, cxt.lwsa, true);
1001 pr_alert("%s", buf);
1002 kfree(buf);
1003
1004 if (cxt.cur_ops->readlock) {
1005 buf = kmalloc(size, GFP_KERNEL);
1006 if (!buf) {
1007 pr_err("lock_torture_stats_print: Out of memory, need: %d",
1008 size);
1009 return;
1010 }
1011
1012 __torture_print_stats(buf, cxt.lrsa, false);
1013 pr_alert("%s", buf);
1014 kfree(buf);
1015 }
1016 }
1017
1018 /*
1019 * Periodically prints torture statistics, if periodic statistics printing
1020 * was specified via the stat_interval module parameter.
1021 *
1022 * No need to worry about fullstop here, since this one doesn't reference
1023 * volatile state or register callbacks.
1024 */
1025 static int lock_torture_stats(void *arg)
1026 {
1027 VERBOSE_TOROUT_STRING("lock_torture_stats task started");
1028 do {
1029 schedule_timeout_interruptible(stat_interval * HZ);
1030 lock_torture_stats_print();
1031 torture_shutdown_absorb("lock_torture_stats");
1032 } while (!torture_must_stop());
1033 torture_kthread_stopping("lock_torture_stats");
1034 return 0;
1035 }
1036
1037
1038 static inline void
1039 lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
1040 const char *tag)
1041 {
1042 static cpumask_t cpumask_all;
1043 cpumask_t *rcmp = cpumask_nonempty(bind_readers) ? bind_readers : &cpumask_all;
1044 cpumask_t *wcmp = cpumask_nonempty(bind_writers) ? bind_writers : &cpumask_all;
1045
1046 cpumask_setall(&cpumask_all);
1047 pr_alert("%s" TORTURE_FLAG
1048 "--- %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",
1049 torture_type, tag, cxt.debug_lock ? " [debug]": "",
1050 acq_writer_lim, cpumask_pr_args(rcmp), cpumask_pr_args(wcmp),
1051 call_rcu_chains, long_hold, nested_locks, cxt.nrealreaders_stress,
1052 cxt.nrealwriters_stress, onoff_holdoff, onoff_interval, rt_boost,
1053 rt_boost_factor, shuffle_interval, shutdown_secs, stat_interval, stutter,
1054 verbose, writer_fifo);
1055 }
1056
1057 // If requested, maintain call_rcu() chains to keep a grace period always
1058 // in flight. These increase the probability of getting an RCU CPU stall
1059 // warning and associated diagnostics when a locking primitive stalls.
1060
1061 static void call_rcu_chain_cb(struct rcu_head *rhp)
1062 {
1063 struct call_rcu_chain *crcp = container_of(rhp, struct call_rcu_chain, crc_rh);
1064
1065 if (!smp_load_acquire(&crcp->crc_stop)) {
1066 (void)start_poll_synchronize_rcu(); // Start one grace period...
1067 call_rcu(&crcp->crc_rh, call_rcu_chain_cb); // ... and later start another.
1068 }
1069 }
1070
1071 // Start the requested number of call_rcu() chains.
1072 static int call_rcu_chain_init(void)
1073 {
1074 int i;
1075
1076 if (call_rcu_chains <= 0)
1077 return 0;
1078 call_rcu_chain_list = kcalloc(call_rcu_chains, sizeof(*call_rcu_chain_list), GFP_KERNEL);
1079 if (!call_rcu_chain_list)
1080 return -ENOMEM;
1081 for (i = 0; i < call_rcu_chains; i++) {
1082 call_rcu_chain_list[i].crc_stop = false;
1083 call_rcu(&call_rcu_chain_list[i].crc_rh, call_rcu_chain_cb);
1084 }
1085 return 0;
1086 }
1087
1088 // Stop all of the call_rcu() chains.
1089 static void call_rcu_chain_cleanup(void)
1090 {
1091 int i;
1092
1093 if (!call_rcu_chain_list)
1094 return;
1095 for (i = 0; i < call_rcu_chains; i++)
1096 smp_store_release(&call_rcu_chain_list[i].crc_stop, true);
1097 rcu_barrier();
1098 kfree(call_rcu_chain_list);
1099 call_rcu_chain_list = NULL;
1100 }
1101
1102 static void lock_torture_cleanup(void)
1103 {
1104 int i;
1105
1106 if (torture_cleanup_begin())
1107 return;
1108
1109 /*
1110 * Indicates early cleanup, meaning that the test has not run,
1111 * such as when passing bogus args when loading the module.
1112 * However cxt->cur_ops.init() may have been invoked, so beside
1113 * perform the underlying torture-specific cleanups, cur_ops.exit()
1114 * will be invoked if needed.
1115 */
1116 if (!cxt.lwsa && !cxt.lrsa)
1117 goto end;
1118
1119 if (writer_tasks) {
1120 for (i = 0; i < cxt.nrealwriters_stress; i++)
1121 torture_stop_kthread(lock_torture_writer, writer_tasks[i]);
1122 kfree(writer_tasks);
1123 writer_tasks = NULL;
1124 }
1125
1126 if (reader_tasks) {
1127 for (i = 0; i < cxt.nrealreaders_stress; i++)
1128 torture_stop_kthread(lock_torture_reader,
1129 reader_tasks[i]);
1130 kfree(reader_tasks);
1131 reader_tasks = NULL;
1132 }
1133
1134 torture_stop_kthread(lock_torture_stats, stats_task);
1135 lock_torture_stats_print(); /* -After- the stats thread is stopped! */
1136
1137 if (atomic_read(&cxt.n_lock_torture_errors))
1138 lock_torture_print_module_parms(cxt.cur_ops,
1139 "End of test: FAILURE");
1140 else if (torture_onoff_failures())
1141 lock_torture_print_module_parms(cxt.cur_ops,
1142 "End of test: LOCK_HOTPLUG");
1143 else
1144 lock_torture_print_module_parms(cxt.cur_ops,
1145 "End of test: SUCCESS");
1146
1147 kfree(cxt.lwsa);
1148 cxt.lwsa = NULL;
1149 kfree(cxt.lrsa);
1150 cxt.lrsa = NULL;
1151
1152 call_rcu_chain_cleanup();
1153
1154 end:
1155 if (cxt.init_called) {
1156 if (cxt.cur_ops->exit)
1157 cxt.cur_ops->exit();
1158 cxt.init_called = false;
1159 }
1160 torture_cleanup_end();
1161 }
1162
1163 static int __init lock_torture_init(void)
1164 {
1165 int i, j;
1166 int firsterr = 0;
1167 static struct lock_torture_ops *torture_ops[] = {
1168 &lock_busted_ops,
1169 &spin_lock_ops, &spin_lock_irq_ops,
1170 &raw_spin_lock_ops, &raw_spin_lock_irq_ops,
1171 &rw_lock_ops, &rw_lock_irq_ops,
1172 &mutex_lock_ops,
1173 &ww_mutex_lock_ops,
1174 #ifdef CONFIG_RT_MUTEXES
1175 &rtmutex_lock_ops,
1176 #endif
1177 &rwsem_lock_ops,
1178 &percpu_rwsem_lock_ops,
1179 };
1180
1181 if (!torture_init_begin(torture_type, verbose))
1182 return -EBUSY;
1183
1184 /* Process args and tell the world that the torturer is on the job. */
1185 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1186 cxt.cur_ops = torture_ops[i];
1187 if (strcmp(torture_type, cxt.cur_ops->name) == 0)
1188 break;
1189 }
1190 if (i == ARRAY_SIZE(torture_ops)) {
1191 pr_alert("lock-torture: invalid torture type: \"%s\"\n",
1192 torture_type);
1193 pr_alert("lock-torture types:");
1194 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1195 pr_alert(" %s", torture_ops[i]->name);
1196 pr_alert("\n");
1197 firsterr = -EINVAL;
1198 goto unwind;
1199 }
1200
1201 if (nwriters_stress == 0 &&
1202 (!cxt.cur_ops->readlock || nreaders_stress == 0)) {
1203 pr_alert("lock-torture: must run at least one locking thread\n");
1204 firsterr = -EINVAL;
1205 goto unwind;
1206 }
1207
1208 if (nwriters_stress >= 0)
1209 cxt.nrealwriters_stress = nwriters_stress;
1210 else
1211 cxt.nrealwriters_stress = 2 * num_online_cpus();
1212
1213 if (cxt.cur_ops->init) {
1214 cxt.cur_ops->init();
1215 cxt.init_called = true;
1216 }
1217
1218 #ifdef CONFIG_DEBUG_MUTEXES
1219 if (str_has_prefix(torture_type, "mutex"))
1220 cxt.debug_lock = true;
1221 #endif
1222 #ifdef CONFIG_DEBUG_RT_MUTEXES
1223 if (str_has_prefix(torture_type, "rtmutex"))
1224 cxt.debug_lock = true;
1225 #endif
1226 #ifdef CONFIG_DEBUG_SPINLOCK
1227 if ((str_has_prefix(torture_type, "spin")) ||
1228 (str_has_prefix(torture_type, "rw_lock")))
1229 cxt.debug_lock = true;
1230 #endif
1231
1232 /* Initialize the statistics so that each run gets its own numbers. */
1233 if (nwriters_stress) {
1234 lock_is_write_held = false;
1235 cxt.lwsa = kmalloc_array(cxt.nrealwriters_stress,
1236 sizeof(*cxt.lwsa),
1237 GFP_KERNEL);
1238 if (cxt.lwsa == NULL) {
1239 VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory");
1240 firsterr = -ENOMEM;
1241 goto unwind;
1242 }
1243
1244 for (i = 0; i < cxt.nrealwriters_stress; i++) {
1245 cxt.lwsa[i].n_lock_fail = 0;
1246 cxt.lwsa[i].n_lock_acquired = 0;
1247 }
1248 }
1249
1250 if (cxt.cur_ops->readlock) {
1251 if (nreaders_stress >= 0)
1252 cxt.nrealreaders_stress = nreaders_stress;
1253 else {
1254 /*
1255 * By default distribute evenly the number of
1256 * readers and writers. We still run the same number
1257 * of threads as the writer-only locks default.
1258 */
1259 if (nwriters_stress < 0) /* user doesn't care */
1260 cxt.nrealwriters_stress = num_online_cpus();
1261 cxt.nrealreaders_stress = cxt.nrealwriters_stress;
1262 }
1263
1264 if (nreaders_stress) {
1265 cxt.lrsa = kmalloc_array(cxt.nrealreaders_stress,
1266 sizeof(*cxt.lrsa),
1267 GFP_KERNEL);
1268 if (cxt.lrsa == NULL) {
1269 VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory");
1270 firsterr = -ENOMEM;
1271 kfree(cxt.lwsa);
1272 cxt.lwsa = NULL;
1273 goto unwind;
1274 }
1275
1276 for (i = 0; i < cxt.nrealreaders_stress; i++) {
1277 cxt.lrsa[i].n_lock_fail = 0;
1278 cxt.lrsa[i].n_lock_acquired = 0;
1279 }
1280 }
1281 }
1282
1283 firsterr = call_rcu_chain_init();
1284 if (torture_init_error(firsterr))
1285 goto unwind;
1286
1287 lock_torture_print_module_parms(cxt.cur_ops, "Start of test");
1288
1289 /* Prepare torture context. */
1290 if (onoff_interval > 0) {
1291 firsterr = torture_onoff_init(onoff_holdoff * HZ,
1292 onoff_interval * HZ, NULL);
1293 if (torture_init_error(firsterr))
1294 goto unwind;
1295 }
1296 if (shuffle_interval > 0) {
1297 firsterr = torture_shuffle_init(shuffle_interval);
1298 if (torture_init_error(firsterr))
1299 goto unwind;
1300 }
1301 if (shutdown_secs > 0) {
1302 firsterr = torture_shutdown_init(shutdown_secs,
1303 lock_torture_cleanup);
1304 if (torture_init_error(firsterr))
1305 goto unwind;
1306 }
1307 if (stutter > 0) {
1308 firsterr = torture_stutter_init(stutter, stutter);
1309 if (torture_init_error(firsterr))
1310 goto unwind;
1311 }
1312
1313 if (nwriters_stress) {
1314 writer_tasks = kcalloc(cxt.nrealwriters_stress,
1315 sizeof(writer_tasks[0]),
1316 GFP_KERNEL);
1317 if (writer_tasks == NULL) {
1318 TOROUT_ERRSTRING("writer_tasks: Out of memory");
1319 firsterr = -ENOMEM;
1320 goto unwind;
1321 }
1322 }
1323
1324 /* cap nested_locks to MAX_NESTED_LOCKS */
1325 if (nested_locks > MAX_NESTED_LOCKS)
1326 nested_locks = MAX_NESTED_LOCKS;
1327
1328 if (cxt.cur_ops->readlock) {
1329 reader_tasks = kcalloc(cxt.nrealreaders_stress,
1330 sizeof(reader_tasks[0]),
1331 GFP_KERNEL);
1332 if (reader_tasks == NULL) {
1333 TOROUT_ERRSTRING("reader_tasks: Out of memory");
1334 kfree(writer_tasks);
1335 writer_tasks = NULL;
1336 firsterr = -ENOMEM;
1337 goto unwind;
1338 }
1339 }
1340
1341 /*
1342 * Create the kthreads and start torturing (oh, those poor little locks).
1343 *
1344 * TODO: Note that we interleave writers with readers, giving writers a
1345 * slight advantage, by creating its kthread first. This can be modified
1346 * for very specific needs, or even let the user choose the policy, if
1347 * ever wanted.
1348 */
1349 for (i = 0, j = 0; i < cxt.nrealwriters_stress ||
1350 j < cxt.nrealreaders_stress; i++, j++) {
1351 if (i >= cxt.nrealwriters_stress)
1352 goto create_reader;
1353
1354 /* Create writer. */
1355 firsterr = torture_create_kthread_cb(lock_torture_writer, &cxt.lwsa[i],
1356 writer_tasks[i],
1357 writer_fifo ? sched_set_fifo : NULL);
1358 if (torture_init_error(firsterr))
1359 goto unwind;
1360 if (cpumask_nonempty(bind_writers))
1361 torture_sched_setaffinity(writer_tasks[i]->pid, bind_writers);
1362
1363 create_reader:
1364 if (cxt.cur_ops->readlock == NULL || (j >= cxt.nrealreaders_stress))
1365 continue;
1366 /* Create reader. */
1367 firsterr = torture_create_kthread(lock_torture_reader, &cxt.lrsa[j],
1368 reader_tasks[j]);
1369 if (torture_init_error(firsterr))
1370 goto unwind;
1371 if (cpumask_nonempty(bind_readers))
1372 torture_sched_setaffinity(reader_tasks[j]->pid, bind_readers);
1373 }
1374 if (stat_interval > 0) {
1375 firsterr = torture_create_kthread(lock_torture_stats, NULL,
1376 stats_task);
1377 if (torture_init_error(firsterr))
1378 goto unwind;
1379 }
1380 torture_init_end();
1381 return 0;
1382
1383 unwind:
1384 torture_init_end();
1385 lock_torture_cleanup();
1386 if (shutdown_secs) {
1387 WARN_ON(!IS_MODULE(CONFIG_LOCK_TORTURE_TEST));
1388 kernel_power_off();
1389 }
1390 return firsterr;
1391 }
1392
1393 module_init(lock_torture_init);
1394 module_exit(lock_torture_cleanup);
1395
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