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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
33MODULE_LICENSE("GPL");
34MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>");
35
36torture_param(int, nwriters_stress, -1,
37 "Number of write-locking stress-test threads");
38torture_param(int, nreaders_stress, -1,
39 "Number of read-locking stress-test threads");
40torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
41torture_param(int, onoff_interval, 0,
42 "Time between CPU hotplugs (s), 0=disable");
43torture_param(int, shuffle_interval, 3,
44 "Number of jiffies between shuffles, 0=disable");
45torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable.");
46torture_param(int, stat_interval, 60,
47 "Number of seconds between stats printk()s");
48torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
49torture_param(int, verbose, 1,
50 "Enable verbose debugging printk()s");
51
52static char *torture_type = "spin_lock";
53module_param(torture_type, charp, 0444);
54MODULE_PARM_DESC(torture_type,
55 "Type of lock to torture (spin_lock, spin_lock_irq, mutex_lock, ...)");
56
57static struct task_struct *stats_task;
58static struct task_struct **writer_tasks;
59static struct task_struct **reader_tasks;
60
61static bool lock_is_write_held;
62static atomic_t lock_is_read_held;
63static unsigned long last_lock_release;
64
65struct lock_stress_stats {
66 long n_lock_fail;
67 long n_lock_acquired;
68};
69
70/* Forward reference. */
71static void lock_torture_cleanup(void);
72
73/*
74 * Operations vector for selecting different types of tests.
75 */
76struct lock_torture_ops {
77 void (*init)(void);
78 void (*exit)(void);
79 int (*writelock)(int tid);
80 void (*write_delay)(struct torture_random_state *trsp);
81 void (*task_boost)(struct torture_random_state *trsp);
82 void (*writeunlock)(int tid);
83 int (*readlock)(int tid);
84 void (*read_delay)(struct torture_random_state *trsp);
85 void (*readunlock)(int tid);
86
87 unsigned long flags; /* for irq spinlocks */
88 const char *name;
89};
90
91struct lock_torture_cxt {
92 int nrealwriters_stress;
93 int nrealreaders_stress;
94 bool debug_lock;
95 bool init_called;
96 atomic_t n_lock_torture_errors;
97 struct lock_torture_ops *cur_ops;
98 struct lock_stress_stats *lwsa; /* writer statistics */
99 struct lock_stress_stats *lrsa; /* reader statistics */
100};
101static struct lock_torture_cxt cxt = { 0, 0, false, false,
102 ATOMIC_INIT(0),
103 NULL, NULL};
104/*
105 * Definitions for lock torture testing.
106 */
107
108static int torture_lock_busted_write_lock(int tid __maybe_unused)
109{
110 return 0; /* BUGGY, do not use in real life!!! */
111}
112
113static void torture_lock_busted_write_delay(struct torture_random_state *trsp)
114{
115 const unsigned long longdelay_ms = 100;
116
117 /* We want a long delay occasionally to force massive contention. */
118 if (!(torture_random(trsp) %
119 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
120 mdelay(longdelay_ms);
121 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
122 torture_preempt_schedule(); /* Allow test to be preempted. */
123}
124
125static void torture_lock_busted_write_unlock(int tid __maybe_unused)
126{
127 /* BUGGY, do not use in real life!!! */
128}
129
130static void torture_boost_dummy(struct torture_random_state *trsp)
131{
132 /* Only rtmutexes care about priority */
133}
134
135static struct lock_torture_ops lock_busted_ops = {
136 .writelock = torture_lock_busted_write_lock,
137 .write_delay = torture_lock_busted_write_delay,
138 .task_boost = torture_boost_dummy,
139 .writeunlock = torture_lock_busted_write_unlock,
140 .readlock = NULL,
141 .read_delay = NULL,
142 .readunlock = NULL,
143 .name = "lock_busted"
144};
145
146static DEFINE_SPINLOCK(torture_spinlock);
147
148static int torture_spin_lock_write_lock(int tid __maybe_unused)
149__acquires(torture_spinlock)
150{
151 spin_lock(&torture_spinlock);
152 return 0;
153}
154
155static void torture_spin_lock_write_delay(struct torture_random_state *trsp)
156{
157 const unsigned long shortdelay_us = 2;
158 const unsigned long longdelay_ms = 100;
159
160 /* We want a short delay mostly to emulate likely code, and
161 * we want a long delay occasionally to force massive contention.
162 */
163 if (!(torture_random(trsp) %
164 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
165 mdelay(longdelay_ms);
166 if (!(torture_random(trsp) %
167 (cxt.nrealwriters_stress * 2 * shortdelay_us)))
168 udelay(shortdelay_us);
169 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
170 torture_preempt_schedule(); /* Allow test to be preempted. */
171}
172
173static void torture_spin_lock_write_unlock(int tid __maybe_unused)
174__releases(torture_spinlock)
175{
176 spin_unlock(&torture_spinlock);
177}
178
179static struct lock_torture_ops spin_lock_ops = {
180 .writelock = torture_spin_lock_write_lock,
181 .write_delay = torture_spin_lock_write_delay,
182 .task_boost = torture_boost_dummy,
183 .writeunlock = torture_spin_lock_write_unlock,
184 .readlock = NULL,
185 .read_delay = NULL,
186 .readunlock = NULL,
187 .name = "spin_lock"
188};
189
190static int torture_spin_lock_write_lock_irq(int tid __maybe_unused)
191__acquires(torture_spinlock)
192{
193 unsigned long flags;
194
195 spin_lock_irqsave(&torture_spinlock, flags);
196 cxt.cur_ops->flags = flags;
197 return 0;
198}
199
200static void torture_lock_spin_write_unlock_irq(int tid __maybe_unused)
201__releases(torture_spinlock)
202{
203 spin_unlock_irqrestore(&torture_spinlock, cxt.cur_ops->flags);
204}
205
206static struct lock_torture_ops spin_lock_irq_ops = {
207 .writelock = torture_spin_lock_write_lock_irq,
208 .write_delay = torture_spin_lock_write_delay,
209 .task_boost = torture_boost_dummy,
210 .writeunlock = torture_lock_spin_write_unlock_irq,
211 .readlock = NULL,
212 .read_delay = NULL,
213 .readunlock = NULL,
214 .name = "spin_lock_irq"
215};
216
217static DEFINE_RWLOCK(torture_rwlock);
218
219static int torture_rwlock_write_lock(int tid __maybe_unused)
220__acquires(torture_rwlock)
221{
222 write_lock(&torture_rwlock);
223 return 0;
224}
225
226static void torture_rwlock_write_delay(struct torture_random_state *trsp)
227{
228 const unsigned long shortdelay_us = 2;
229 const unsigned long longdelay_ms = 100;
230
231 /* We want a short delay mostly to emulate likely code, and
232 * we want a long delay occasionally to force massive contention.
233 */
234 if (!(torture_random(trsp) %
235 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
236 mdelay(longdelay_ms);
237 else
238 udelay(shortdelay_us);
239}
240
241static void torture_rwlock_write_unlock(int tid __maybe_unused)
242__releases(torture_rwlock)
243{
244 write_unlock(&torture_rwlock);
245}
246
247static int torture_rwlock_read_lock(int tid __maybe_unused)
248__acquires(torture_rwlock)
249{
250 read_lock(&torture_rwlock);
251 return 0;
252}
253
254static void torture_rwlock_read_delay(struct torture_random_state *trsp)
255{
256 const unsigned long shortdelay_us = 10;
257 const unsigned long longdelay_ms = 100;
258
259 /* We want a short delay mostly to emulate likely code, and
260 * we want a long delay occasionally to force massive contention.
261 */
262 if (!(torture_random(trsp) %
263 (cxt.nrealreaders_stress * 2000 * longdelay_ms)))
264 mdelay(longdelay_ms);
265 else
266 udelay(shortdelay_us);
267}
268
269static void torture_rwlock_read_unlock(int tid __maybe_unused)
270__releases(torture_rwlock)
271{
272 read_unlock(&torture_rwlock);
273}
274
275static struct lock_torture_ops rw_lock_ops = {
276 .writelock = torture_rwlock_write_lock,
277 .write_delay = torture_rwlock_write_delay,
278 .task_boost = torture_boost_dummy,
279 .writeunlock = torture_rwlock_write_unlock,
280 .readlock = torture_rwlock_read_lock,
281 .read_delay = torture_rwlock_read_delay,
282 .readunlock = torture_rwlock_read_unlock,
283 .name = "rw_lock"
284};
285
286static int torture_rwlock_write_lock_irq(int tid __maybe_unused)
287__acquires(torture_rwlock)
288{
289 unsigned long flags;
290
291 write_lock_irqsave(&torture_rwlock, flags);
292 cxt.cur_ops->flags = flags;
293 return 0;
294}
295
296static void torture_rwlock_write_unlock_irq(int tid __maybe_unused)
297__releases(torture_rwlock)
298{
299 write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
300}
301
302static int torture_rwlock_read_lock_irq(int tid __maybe_unused)
303__acquires(torture_rwlock)
304{
305 unsigned long flags;
306
307 read_lock_irqsave(&torture_rwlock, flags);
308 cxt.cur_ops->flags = flags;
309 return 0;
310}
311
312static void torture_rwlock_read_unlock_irq(int tid __maybe_unused)
313__releases(torture_rwlock)
314{
315 read_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
316}
317
318static struct lock_torture_ops rw_lock_irq_ops = {
319 .writelock = torture_rwlock_write_lock_irq,
320 .write_delay = torture_rwlock_write_delay,
321 .task_boost = torture_boost_dummy,
322 .writeunlock = torture_rwlock_write_unlock_irq,
323 .readlock = torture_rwlock_read_lock_irq,
324 .read_delay = torture_rwlock_read_delay,
325 .readunlock = torture_rwlock_read_unlock_irq,
326 .name = "rw_lock_irq"
327};
328
329static DEFINE_MUTEX(torture_mutex);
330
331static int torture_mutex_lock(int tid __maybe_unused)
332__acquires(torture_mutex)
333{
334 mutex_lock(&torture_mutex);
335 return 0;
336}
337
338static void torture_mutex_delay(struct torture_random_state *trsp)
339{
340 const unsigned long longdelay_ms = 100;
341
342 /* We want a long delay occasionally to force massive contention. */
343 if (!(torture_random(trsp) %
344 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
345 mdelay(longdelay_ms * 5);
346 else
347 mdelay(longdelay_ms / 5);
348 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
349 torture_preempt_schedule(); /* Allow test to be preempted. */
350}
351
352static void torture_mutex_unlock(int tid __maybe_unused)
353__releases(torture_mutex)
354{
355 mutex_unlock(&torture_mutex);
356}
357
358static struct lock_torture_ops mutex_lock_ops = {
359 .writelock = torture_mutex_lock,
360 .write_delay = torture_mutex_delay,
361 .task_boost = torture_boost_dummy,
362 .writeunlock = torture_mutex_unlock,
363 .readlock = NULL,
364 .read_delay = NULL,
365 .readunlock = NULL,
366 .name = "mutex_lock"
367};
368
369#include <linux/ww_mutex.h>
370/*
371 * The torture ww_mutexes should belong to the same lock class as
372 * torture_ww_class to avoid lockdep problem. The ww_mutex_init()
373 * function is called for initialization to ensure that.
374 */
375static DEFINE_WD_CLASS(torture_ww_class);
376static struct ww_mutex torture_ww_mutex_0, torture_ww_mutex_1, torture_ww_mutex_2;
377static struct ww_acquire_ctx *ww_acquire_ctxs;
378
379static void torture_ww_mutex_init(void)
380{
381 ww_mutex_init(&torture_ww_mutex_0, &torture_ww_class);
382 ww_mutex_init(&torture_ww_mutex_1, &torture_ww_class);
383 ww_mutex_init(&torture_ww_mutex_2, &torture_ww_class);
384
385 ww_acquire_ctxs = kmalloc_array(cxt.nrealwriters_stress,
386 sizeof(*ww_acquire_ctxs),
387 GFP_KERNEL);
388 if (!ww_acquire_ctxs)
389 VERBOSE_TOROUT_STRING("ww_acquire_ctx: Out of memory");
390}
391
392static void torture_ww_mutex_exit(void)
393{
394 kfree(ww_acquire_ctxs);
395}
396
397static int torture_ww_mutex_lock(int tid)
398__acquires(torture_ww_mutex_0)
399__acquires(torture_ww_mutex_1)
400__acquires(torture_ww_mutex_2)
401{
402 LIST_HEAD(list);
403 struct reorder_lock {
404 struct list_head link;
405 struct ww_mutex *lock;
406 } locks[3], *ll, *ln;
407 struct ww_acquire_ctx *ctx = &ww_acquire_ctxs[tid];
408
409 locks[0].lock = &torture_ww_mutex_0;
410 list_add(&locks[0].link, &list);
411
412 locks[1].lock = &torture_ww_mutex_1;
413 list_add(&locks[1].link, &list);
414
415 locks[2].lock = &torture_ww_mutex_2;
416 list_add(&locks[2].link, &list);
417
418 ww_acquire_init(ctx, &torture_ww_class);
419
420 list_for_each_entry(ll, &list, link) {
421 int err;
422
423 err = ww_mutex_lock(ll->lock, ctx);
424 if (!err)
425 continue;
426
427 ln = ll;
428 list_for_each_entry_continue_reverse(ln, &list, link)
429 ww_mutex_unlock(ln->lock);
430
431 if (err != -EDEADLK)
432 return err;
433
434 ww_mutex_lock_slow(ll->lock, ctx);
435 list_move(&ll->link, &list);
436 }
437
438 return 0;
439}
440
441static void torture_ww_mutex_unlock(int tid)
442__releases(torture_ww_mutex_0)
443__releases(torture_ww_mutex_1)
444__releases(torture_ww_mutex_2)
445{
446 struct ww_acquire_ctx *ctx = &ww_acquire_ctxs[tid];
447
448 ww_mutex_unlock(&torture_ww_mutex_0);
449 ww_mutex_unlock(&torture_ww_mutex_1);
450 ww_mutex_unlock(&torture_ww_mutex_2);
451 ww_acquire_fini(ctx);
452}
453
454static struct lock_torture_ops ww_mutex_lock_ops = {
455 .init = torture_ww_mutex_init,
456 .exit = torture_ww_mutex_exit,
457 .writelock = torture_ww_mutex_lock,
458 .write_delay = torture_mutex_delay,
459 .task_boost = torture_boost_dummy,
460 .writeunlock = torture_ww_mutex_unlock,
461 .readlock = NULL,
462 .read_delay = NULL,
463 .readunlock = NULL,
464 .name = "ww_mutex_lock"
465};
466
467#ifdef CONFIG_RT_MUTEXES
468static DEFINE_RT_MUTEX(torture_rtmutex);
469
470static int torture_rtmutex_lock(int tid __maybe_unused)
471__acquires(torture_rtmutex)
472{
473 rt_mutex_lock(&torture_rtmutex);
474 return 0;
475}
476
477static void torture_rtmutex_boost(struct torture_random_state *trsp)
478{
479 const unsigned int factor = 50000; /* yes, quite arbitrary */
480
481 if (!rt_task(current)) {
482 /*
483 * Boost priority once every ~50k operations. When the
484 * task tries to take the lock, the rtmutex it will account
485 * for the new priority, and do any corresponding pi-dance.
486 */
487 if (trsp && !(torture_random(trsp) %
488 (cxt.nrealwriters_stress * factor))) {
489 sched_set_fifo(current);
490 } else /* common case, do nothing */
491 return;
492 } else {
493 /*
494 * The task will remain boosted for another ~500k operations,
495 * then restored back to its original prio, and so forth.
496 *
497 * When @trsp is nil, we want to force-reset the task for
498 * stopping the kthread.
499 */
500 if (!trsp || !(torture_random(trsp) %
501 (cxt.nrealwriters_stress * factor * 2))) {
502 sched_set_normal(current, 0);
503 } else /* common case, do nothing */
504 return;
505 }
506}
507
508static void torture_rtmutex_delay(struct torture_random_state *trsp)
509{
510 const unsigned long shortdelay_us = 2;
511 const unsigned long longdelay_ms = 100;
512
513 /*
514 * We want a short delay mostly to emulate likely code, and
515 * we want a long delay occasionally to force massive contention.
516 */
517 if (!(torture_random(trsp) %
518 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
519 mdelay(longdelay_ms);
520 if (!(torture_random(trsp) %
521 (cxt.nrealwriters_stress * 2 * shortdelay_us)))
522 udelay(shortdelay_us);
523 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
524 torture_preempt_schedule(); /* Allow test to be preempted. */
525}
526
527static void torture_rtmutex_unlock(int tid __maybe_unused)
528__releases(torture_rtmutex)
529{
530 rt_mutex_unlock(&torture_rtmutex);
531}
532
533static struct lock_torture_ops rtmutex_lock_ops = {
534 .writelock = torture_rtmutex_lock,
535 .write_delay = torture_rtmutex_delay,
536 .task_boost = torture_rtmutex_boost,
537 .writeunlock = torture_rtmutex_unlock,
538 .readlock = NULL,
539 .read_delay = NULL,
540 .readunlock = NULL,
541 .name = "rtmutex_lock"
542};
543#endif
544
545static DECLARE_RWSEM(torture_rwsem);
546static int torture_rwsem_down_write(int tid __maybe_unused)
547__acquires(torture_rwsem)
548{
549 down_write(&torture_rwsem);
550 return 0;
551}
552
553static void torture_rwsem_write_delay(struct torture_random_state *trsp)
554{
555 const unsigned long longdelay_ms = 100;
556
557 /* We want a long delay occasionally to force massive contention. */
558 if (!(torture_random(trsp) %
559 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
560 mdelay(longdelay_ms * 10);
561 else
562 mdelay(longdelay_ms / 10);
563 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
564 torture_preempt_schedule(); /* Allow test to be preempted. */
565}
566
567static void torture_rwsem_up_write(int tid __maybe_unused)
568__releases(torture_rwsem)
569{
570 up_write(&torture_rwsem);
571}
572
573static int torture_rwsem_down_read(int tid __maybe_unused)
574__acquires(torture_rwsem)
575{
576 down_read(&torture_rwsem);
577 return 0;
578}
579
580static void torture_rwsem_read_delay(struct torture_random_state *trsp)
581{
582 const unsigned long longdelay_ms = 100;
583
584 /* We want a long delay occasionally to force massive contention. */
585 if (!(torture_random(trsp) %
586 (cxt.nrealreaders_stress * 2000 * longdelay_ms)))
587 mdelay(longdelay_ms * 2);
588 else
589 mdelay(longdelay_ms / 2);
590 if (!(torture_random(trsp) % (cxt.nrealreaders_stress * 20000)))
591 torture_preempt_schedule(); /* Allow test to be preempted. */
592}
593
594static void torture_rwsem_up_read(int tid __maybe_unused)
595__releases(torture_rwsem)
596{
597 up_read(&torture_rwsem);
598}
599
600static struct lock_torture_ops rwsem_lock_ops = {
601 .writelock = torture_rwsem_down_write,
602 .write_delay = torture_rwsem_write_delay,
603 .task_boost = torture_boost_dummy,
604 .writeunlock = torture_rwsem_up_write,
605 .readlock = torture_rwsem_down_read,
606 .read_delay = torture_rwsem_read_delay,
607 .readunlock = torture_rwsem_up_read,
608 .name = "rwsem_lock"
609};
610
611#include <linux/percpu-rwsem.h>
612static struct percpu_rw_semaphore pcpu_rwsem;
613
614static void torture_percpu_rwsem_init(void)
615{
616 BUG_ON(percpu_init_rwsem(&pcpu_rwsem));
617}
618
619static void torture_percpu_rwsem_exit(void)
620{
621 percpu_free_rwsem(&pcpu_rwsem);
622}
623
624static int torture_percpu_rwsem_down_write(int tid __maybe_unused)
625__acquires(pcpu_rwsem)
626{
627 percpu_down_write(&pcpu_rwsem);
628 return 0;
629}
630
631static void torture_percpu_rwsem_up_write(int tid __maybe_unused)
632__releases(pcpu_rwsem)
633{
634 percpu_up_write(&pcpu_rwsem);
635}
636
637static int torture_percpu_rwsem_down_read(int tid __maybe_unused)
638__acquires(pcpu_rwsem)
639{
640 percpu_down_read(&pcpu_rwsem);
641 return 0;
642}
643
644static void torture_percpu_rwsem_up_read(int tid __maybe_unused)
645__releases(pcpu_rwsem)
646{
647 percpu_up_read(&pcpu_rwsem);
648}
649
650static struct lock_torture_ops percpu_rwsem_lock_ops = {
651 .init = torture_percpu_rwsem_init,
652 .exit = torture_percpu_rwsem_exit,
653 .writelock = torture_percpu_rwsem_down_write,
654 .write_delay = torture_rwsem_write_delay,
655 .task_boost = torture_boost_dummy,
656 .writeunlock = torture_percpu_rwsem_up_write,
657 .readlock = torture_percpu_rwsem_down_read,
658 .read_delay = torture_rwsem_read_delay,
659 .readunlock = torture_percpu_rwsem_up_read,
660 .name = "percpu_rwsem_lock"
661};
662
663/*
664 * Lock torture writer kthread. Repeatedly acquires and releases
665 * the lock, checking for duplicate acquisitions.
666 */
667static int lock_torture_writer(void *arg)
668{
669 struct lock_stress_stats *lwsp = arg;
670 int tid = lwsp - cxt.lwsa;
671 DEFINE_TORTURE_RANDOM(rand);
672
673 VERBOSE_TOROUT_STRING("lock_torture_writer task started");
674 set_user_nice(current, MAX_NICE);
675
676 do {
677 if ((torture_random(&rand) & 0xfffff) == 0)
678 schedule_timeout_uninterruptible(1);
679
680 cxt.cur_ops->task_boost(&rand);
681 cxt.cur_ops->writelock(tid);
682 if (WARN_ON_ONCE(lock_is_write_held))
683 lwsp->n_lock_fail++;
684 lock_is_write_held = true;
685 if (WARN_ON_ONCE(atomic_read(&lock_is_read_held)))
686 lwsp->n_lock_fail++; /* rare, but... */
687
688 lwsp->n_lock_acquired++;
689 cxt.cur_ops->write_delay(&rand);
690 lock_is_write_held = false;
691 WRITE_ONCE(last_lock_release, jiffies);
692 cxt.cur_ops->writeunlock(tid);
693
694 stutter_wait("lock_torture_writer");
695 } while (!torture_must_stop());
696
697 cxt.cur_ops->task_boost(NULL); /* reset prio */
698 torture_kthread_stopping("lock_torture_writer");
699 return 0;
700}
701
702/*
703 * Lock torture reader kthread. Repeatedly acquires and releases
704 * the reader lock.
705 */
706static int lock_torture_reader(void *arg)
707{
708 struct lock_stress_stats *lrsp = arg;
709 int tid = lrsp - cxt.lrsa;
710 DEFINE_TORTURE_RANDOM(rand);
711
712 VERBOSE_TOROUT_STRING("lock_torture_reader task started");
713 set_user_nice(current, MAX_NICE);
714
715 do {
716 if ((torture_random(&rand) & 0xfffff) == 0)
717 schedule_timeout_uninterruptible(1);
718
719 cxt.cur_ops->readlock(tid);
720 atomic_inc(&lock_is_read_held);
721 if (WARN_ON_ONCE(lock_is_write_held))
722 lrsp->n_lock_fail++; /* rare, but... */
723
724 lrsp->n_lock_acquired++;
725 cxt.cur_ops->read_delay(&rand);
726 atomic_dec(&lock_is_read_held);
727 cxt.cur_ops->readunlock(tid);
728
729 stutter_wait("lock_torture_reader");
730 } while (!torture_must_stop());
731 torture_kthread_stopping("lock_torture_reader");
732 return 0;
733}
734
735/*
736 * Create an lock-torture-statistics message in the specified buffer.
737 */
738static void __torture_print_stats(char *page,
739 struct lock_stress_stats *statp, bool write)
740{
741 long cur;
742 bool fail = false;
743 int i, n_stress;
744 long max = 0, min = statp ? data_race(statp[0].n_lock_acquired) : 0;
745 long long sum = 0;
746
747 n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress;
748 for (i = 0; i < n_stress; i++) {
749 if (data_race(statp[i].n_lock_fail))
750 fail = true;
751 cur = data_race(statp[i].n_lock_acquired);
752 sum += cur;
753 if (max < cur)
754 max = cur;
755 if (min > cur)
756 min = cur;
757 }
758 page += sprintf(page,
759 "%s: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n",
760 write ? "Writes" : "Reads ",
761 sum, max, min,
762 !onoff_interval && max / 2 > min ? "???" : "",
763 fail, fail ? "!!!" : "");
764 if (fail)
765 atomic_inc(&cxt.n_lock_torture_errors);
766}
767
768/*
769 * Print torture statistics. Caller must ensure that there is only one
770 * call to this function at a given time!!! This is normally accomplished
771 * by relying on the module system to only have one copy of the module
772 * loaded, and then by giving the lock_torture_stats kthread full control
773 * (or the init/cleanup functions when lock_torture_stats thread is not
774 * running).
775 */
776static void lock_torture_stats_print(void)
777{
778 int size = cxt.nrealwriters_stress * 200 + 8192;
779 char *buf;
780
781 if (cxt.cur_ops->readlock)
782 size += cxt.nrealreaders_stress * 200 + 8192;
783
784 buf = kmalloc(size, GFP_KERNEL);
785 if (!buf) {
786 pr_err("lock_torture_stats_print: Out of memory, need: %d",
787 size);
788 return;
789 }
790
791 __torture_print_stats(buf, cxt.lwsa, true);
792 pr_alert("%s", buf);
793 kfree(buf);
794
795 if (cxt.cur_ops->readlock) {
796 buf = kmalloc(size, GFP_KERNEL);
797 if (!buf) {
798 pr_err("lock_torture_stats_print: Out of memory, need: %d",
799 size);
800 return;
801 }
802
803 __torture_print_stats(buf, cxt.lrsa, false);
804 pr_alert("%s", buf);
805 kfree(buf);
806 }
807}
808
809/*
810 * Periodically prints torture statistics, if periodic statistics printing
811 * was specified via the stat_interval module parameter.
812 *
813 * No need to worry about fullstop here, since this one doesn't reference
814 * volatile state or register callbacks.
815 */
816static int lock_torture_stats(void *arg)
817{
818 VERBOSE_TOROUT_STRING("lock_torture_stats task started");
819 do {
820 schedule_timeout_interruptible(stat_interval * HZ);
821 lock_torture_stats_print();
822 torture_shutdown_absorb("lock_torture_stats");
823 } while (!torture_must_stop());
824 torture_kthread_stopping("lock_torture_stats");
825 return 0;
826}
827
828static inline void
829lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
830 const char *tag)
831{
832 pr_alert("%s" TORTURE_FLAG
833 "--- %s%s: nwriters_stress=%d nreaders_stress=%d stat_interval=%d verbose=%d shuffle_interval=%d stutter=%d shutdown_secs=%d onoff_interval=%d onoff_holdoff=%d\n",
834 torture_type, tag, cxt.debug_lock ? " [debug]": "",
835 cxt.nrealwriters_stress, cxt.nrealreaders_stress, stat_interval,
836 verbose, shuffle_interval, stutter, shutdown_secs,
837 onoff_interval, onoff_holdoff);
838}
839
840static void lock_torture_cleanup(void)
841{
842 int i;
843
844 if (torture_cleanup_begin())
845 return;
846
847 /*
848 * Indicates early cleanup, meaning that the test has not run,
849 * such as when passing bogus args when loading the module.
850 * However cxt->cur_ops.init() may have been invoked, so beside
851 * perform the underlying torture-specific cleanups, cur_ops.exit()
852 * will be invoked if needed.
853 */
854 if (!cxt.lwsa && !cxt.lrsa)
855 goto end;
856
857 if (writer_tasks) {
858 for (i = 0; i < cxt.nrealwriters_stress; i++)
859 torture_stop_kthread(lock_torture_writer,
860 writer_tasks[i]);
861 kfree(writer_tasks);
862 writer_tasks = NULL;
863 }
864
865 if (reader_tasks) {
866 for (i = 0; i < cxt.nrealreaders_stress; i++)
867 torture_stop_kthread(lock_torture_reader,
868 reader_tasks[i]);
869 kfree(reader_tasks);
870 reader_tasks = NULL;
871 }
872
873 torture_stop_kthread(lock_torture_stats, stats_task);
874 lock_torture_stats_print(); /* -After- the stats thread is stopped! */
875
876 if (atomic_read(&cxt.n_lock_torture_errors))
877 lock_torture_print_module_parms(cxt.cur_ops,
878 "End of test: FAILURE");
879 else if (torture_onoff_failures())
880 lock_torture_print_module_parms(cxt.cur_ops,
881 "End of test: LOCK_HOTPLUG");
882 else
883 lock_torture_print_module_parms(cxt.cur_ops,
884 "End of test: SUCCESS");
885
886 kfree(cxt.lwsa);
887 cxt.lwsa = NULL;
888 kfree(cxt.lrsa);
889 cxt.lrsa = NULL;
890
891end:
892 if (cxt.init_called) {
893 if (cxt.cur_ops->exit)
894 cxt.cur_ops->exit();
895 cxt.init_called = false;
896 }
897 torture_cleanup_end();
898}
899
900static int __init lock_torture_init(void)
901{
902 int i, j;
903 int firsterr = 0;
904 static struct lock_torture_ops *torture_ops[] = {
905 &lock_busted_ops,
906 &spin_lock_ops, &spin_lock_irq_ops,
907 &rw_lock_ops, &rw_lock_irq_ops,
908 &mutex_lock_ops,
909 &ww_mutex_lock_ops,
910#ifdef CONFIG_RT_MUTEXES
911 &rtmutex_lock_ops,
912#endif
913 &rwsem_lock_ops,
914 &percpu_rwsem_lock_ops,
915 };
916
917 if (!torture_init_begin(torture_type, verbose))
918 return -EBUSY;
919
920 /* Process args and tell the world that the torturer is on the job. */
921 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
922 cxt.cur_ops = torture_ops[i];
923 if (strcmp(torture_type, cxt.cur_ops->name) == 0)
924 break;
925 }
926 if (i == ARRAY_SIZE(torture_ops)) {
927 pr_alert("lock-torture: invalid torture type: \"%s\"\n",
928 torture_type);
929 pr_alert("lock-torture types:");
930 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
931 pr_alert(" %s", torture_ops[i]->name);
932 pr_alert("\n");
933 firsterr = -EINVAL;
934 goto unwind;
935 }
936
937 if (nwriters_stress == 0 &&
938 (!cxt.cur_ops->readlock || nreaders_stress == 0)) {
939 pr_alert("lock-torture: must run at least one locking thread\n");
940 firsterr = -EINVAL;
941 goto unwind;
942 }
943
944 if (nwriters_stress >= 0)
945 cxt.nrealwriters_stress = nwriters_stress;
946 else
947 cxt.nrealwriters_stress = 2 * num_online_cpus();
948
949 if (cxt.cur_ops->init) {
950 cxt.cur_ops->init();
951 cxt.init_called = true;
952 }
953
954#ifdef CONFIG_DEBUG_MUTEXES
955 if (str_has_prefix(torture_type, "mutex"))
956 cxt.debug_lock = true;
957#endif
958#ifdef CONFIG_DEBUG_RT_MUTEXES
959 if (str_has_prefix(torture_type, "rtmutex"))
960 cxt.debug_lock = true;
961#endif
962#ifdef CONFIG_DEBUG_SPINLOCK
963 if ((str_has_prefix(torture_type, "spin")) ||
964 (str_has_prefix(torture_type, "rw_lock")))
965 cxt.debug_lock = true;
966#endif
967
968 /* Initialize the statistics so that each run gets its own numbers. */
969 if (nwriters_stress) {
970 lock_is_write_held = false;
971 cxt.lwsa = kmalloc_array(cxt.nrealwriters_stress,
972 sizeof(*cxt.lwsa),
973 GFP_KERNEL);
974 if (cxt.lwsa == NULL) {
975 VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory");
976 firsterr = -ENOMEM;
977 goto unwind;
978 }
979
980 for (i = 0; i < cxt.nrealwriters_stress; i++) {
981 cxt.lwsa[i].n_lock_fail = 0;
982 cxt.lwsa[i].n_lock_acquired = 0;
983 }
984 }
985
986 if (cxt.cur_ops->readlock) {
987 if (nreaders_stress >= 0)
988 cxt.nrealreaders_stress = nreaders_stress;
989 else {
990 /*
991 * By default distribute evenly the number of
992 * readers and writers. We still run the same number
993 * of threads as the writer-only locks default.
994 */
995 if (nwriters_stress < 0) /* user doesn't care */
996 cxt.nrealwriters_stress = num_online_cpus();
997 cxt.nrealreaders_stress = cxt.nrealwriters_stress;
998 }
999
1000 if (nreaders_stress) {
1001 cxt.lrsa = kmalloc_array(cxt.nrealreaders_stress,
1002 sizeof(*cxt.lrsa),
1003 GFP_KERNEL);
1004 if (cxt.lrsa == NULL) {
1005 VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory");
1006 firsterr = -ENOMEM;
1007 kfree(cxt.lwsa);
1008 cxt.lwsa = NULL;
1009 goto unwind;
1010 }
1011
1012 for (i = 0; i < cxt.nrealreaders_stress; i++) {
1013 cxt.lrsa[i].n_lock_fail = 0;
1014 cxt.lrsa[i].n_lock_acquired = 0;
1015 }
1016 }
1017 }
1018
1019 lock_torture_print_module_parms(cxt.cur_ops, "Start of test");
1020
1021 /* Prepare torture context. */
1022 if (onoff_interval > 0) {
1023 firsterr = torture_onoff_init(onoff_holdoff * HZ,
1024 onoff_interval * HZ, NULL);
1025 if (torture_init_error(firsterr))
1026 goto unwind;
1027 }
1028 if (shuffle_interval > 0) {
1029 firsterr = torture_shuffle_init(shuffle_interval);
1030 if (torture_init_error(firsterr))
1031 goto unwind;
1032 }
1033 if (shutdown_secs > 0) {
1034 firsterr = torture_shutdown_init(shutdown_secs,
1035 lock_torture_cleanup);
1036 if (torture_init_error(firsterr))
1037 goto unwind;
1038 }
1039 if (stutter > 0) {
1040 firsterr = torture_stutter_init(stutter, stutter);
1041 if (torture_init_error(firsterr))
1042 goto unwind;
1043 }
1044
1045 if (nwriters_stress) {
1046 writer_tasks = kcalloc(cxt.nrealwriters_stress,
1047 sizeof(writer_tasks[0]),
1048 GFP_KERNEL);
1049 if (writer_tasks == NULL) {
1050 TOROUT_ERRSTRING("writer_tasks: Out of memory");
1051 firsterr = -ENOMEM;
1052 goto unwind;
1053 }
1054 }
1055
1056 if (cxt.cur_ops->readlock) {
1057 reader_tasks = kcalloc(cxt.nrealreaders_stress,
1058 sizeof(reader_tasks[0]),
1059 GFP_KERNEL);
1060 if (reader_tasks == NULL) {
1061 TOROUT_ERRSTRING("reader_tasks: Out of memory");
1062 kfree(writer_tasks);
1063 writer_tasks = NULL;
1064 firsterr = -ENOMEM;
1065 goto unwind;
1066 }
1067 }
1068
1069 /*
1070 * Create the kthreads and start torturing (oh, those poor little locks).
1071 *
1072 * TODO: Note that we interleave writers with readers, giving writers a
1073 * slight advantage, by creating its kthread first. This can be modified
1074 * for very specific needs, or even let the user choose the policy, if
1075 * ever wanted.
1076 */
1077 for (i = 0, j = 0; i < cxt.nrealwriters_stress ||
1078 j < cxt.nrealreaders_stress; i++, j++) {
1079 if (i >= cxt.nrealwriters_stress)
1080 goto create_reader;
1081
1082 /* Create writer. */
1083 firsterr = torture_create_kthread(lock_torture_writer, &cxt.lwsa[i],
1084 writer_tasks[i]);
1085 if (torture_init_error(firsterr))
1086 goto unwind;
1087
1088 create_reader:
1089 if (cxt.cur_ops->readlock == NULL || (j >= cxt.nrealreaders_stress))
1090 continue;
1091 /* Create reader. */
1092 firsterr = torture_create_kthread(lock_torture_reader, &cxt.lrsa[j],
1093 reader_tasks[j]);
1094 if (torture_init_error(firsterr))
1095 goto unwind;
1096 }
1097 if (stat_interval > 0) {
1098 firsterr = torture_create_kthread(lock_torture_stats, NULL,
1099 stats_task);
1100 if (torture_init_error(firsterr))
1101 goto unwind;
1102 }
1103 torture_init_end();
1104 return 0;
1105
1106unwind:
1107 torture_init_end();
1108 lock_torture_cleanup();
1109 if (shutdown_secs) {
1110 WARN_ON(!IS_MODULE(CONFIG_LOCK_TORTURE_TEST));
1111 kernel_power_off();
1112 }
1113 return firsterr;
1114}
1115
1116module_init(lock_torture_init);
1117module_exit(lock_torture_cleanup);
1/*
2 * Module-based torture test facility for locking
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, you can access it online at
16 * http://www.gnu.org/licenses/gpl-2.0.html.
17 *
18 * Copyright (C) IBM Corporation, 2014
19 *
20 * Authors: Paul E. McKenney <paulmck@us.ibm.com>
21 * Davidlohr Bueso <dave@stgolabs.net>
22 * Based on kernel/rcu/torture.c.
23 */
24#include <linux/kernel.h>
25#include <linux/module.h>
26#include <linux/kthread.h>
27#include <linux/sched/rt.h>
28#include <linux/spinlock.h>
29#include <linux/rwlock.h>
30#include <linux/mutex.h>
31#include <linux/rwsem.h>
32#include <linux/smp.h>
33#include <linux/interrupt.h>
34#include <linux/sched.h>
35#include <linux/atomic.h>
36#include <linux/moduleparam.h>
37#include <linux/delay.h>
38#include <linux/slab.h>
39#include <linux/percpu-rwsem.h>
40#include <linux/torture.h>
41
42MODULE_LICENSE("GPL");
43MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
44
45torture_param(int, nwriters_stress, -1,
46 "Number of write-locking stress-test threads");
47torture_param(int, nreaders_stress, -1,
48 "Number of read-locking stress-test threads");
49torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
50torture_param(int, onoff_interval, 0,
51 "Time between CPU hotplugs (s), 0=disable");
52torture_param(int, shuffle_interval, 3,
53 "Number of jiffies between shuffles, 0=disable");
54torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable.");
55torture_param(int, stat_interval, 60,
56 "Number of seconds between stats printk()s");
57torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
58torture_param(bool, verbose, true,
59 "Enable verbose debugging printk()s");
60
61static char *torture_type = "spin_lock";
62module_param(torture_type, charp, 0444);
63MODULE_PARM_DESC(torture_type,
64 "Type of lock to torture (spin_lock, spin_lock_irq, mutex_lock, ...)");
65
66static struct task_struct *stats_task;
67static struct task_struct **writer_tasks;
68static struct task_struct **reader_tasks;
69
70static bool lock_is_write_held;
71static bool lock_is_read_held;
72
73struct lock_stress_stats {
74 long n_lock_fail;
75 long n_lock_acquired;
76};
77
78int torture_runnable = IS_ENABLED(MODULE);
79module_param(torture_runnable, int, 0444);
80MODULE_PARM_DESC(torture_runnable, "Start locktorture at module init");
81
82/* Forward reference. */
83static void lock_torture_cleanup(void);
84
85/*
86 * Operations vector for selecting different types of tests.
87 */
88struct lock_torture_ops {
89 void (*init)(void);
90 int (*writelock)(void);
91 void (*write_delay)(struct torture_random_state *trsp);
92 void (*task_boost)(struct torture_random_state *trsp);
93 void (*writeunlock)(void);
94 int (*readlock)(void);
95 void (*read_delay)(struct torture_random_state *trsp);
96 void (*readunlock)(void);
97
98 unsigned long flags; /* for irq spinlocks */
99 const char *name;
100};
101
102struct lock_torture_cxt {
103 int nrealwriters_stress;
104 int nrealreaders_stress;
105 bool debug_lock;
106 atomic_t n_lock_torture_errors;
107 struct lock_torture_ops *cur_ops;
108 struct lock_stress_stats *lwsa; /* writer statistics */
109 struct lock_stress_stats *lrsa; /* reader statistics */
110};
111static struct lock_torture_cxt cxt = { 0, 0, false,
112 ATOMIC_INIT(0),
113 NULL, NULL};
114/*
115 * Definitions for lock torture testing.
116 */
117
118static int torture_lock_busted_write_lock(void)
119{
120 return 0; /* BUGGY, do not use in real life!!! */
121}
122
123static void torture_lock_busted_write_delay(struct torture_random_state *trsp)
124{
125 const unsigned long longdelay_ms = 100;
126
127 /* We want a long delay occasionally to force massive contention. */
128 if (!(torture_random(trsp) %
129 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
130 mdelay(longdelay_ms);
131#ifdef CONFIG_PREEMPT
132 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
133 preempt_schedule(); /* Allow test to be preempted. */
134#endif
135}
136
137static void torture_lock_busted_write_unlock(void)
138{
139 /* BUGGY, do not use in real life!!! */
140}
141
142static void torture_boost_dummy(struct torture_random_state *trsp)
143{
144 /* Only rtmutexes care about priority */
145}
146
147static struct lock_torture_ops lock_busted_ops = {
148 .writelock = torture_lock_busted_write_lock,
149 .write_delay = torture_lock_busted_write_delay,
150 .task_boost = torture_boost_dummy,
151 .writeunlock = torture_lock_busted_write_unlock,
152 .readlock = NULL,
153 .read_delay = NULL,
154 .readunlock = NULL,
155 .name = "lock_busted"
156};
157
158static DEFINE_SPINLOCK(torture_spinlock);
159
160static int torture_spin_lock_write_lock(void) __acquires(torture_spinlock)
161{
162 spin_lock(&torture_spinlock);
163 return 0;
164}
165
166static void torture_spin_lock_write_delay(struct torture_random_state *trsp)
167{
168 const unsigned long shortdelay_us = 2;
169 const unsigned long longdelay_ms = 100;
170
171 /* We want a short delay mostly to emulate likely code, and
172 * we want a long delay occasionally to force massive contention.
173 */
174 if (!(torture_random(trsp) %
175 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
176 mdelay(longdelay_ms);
177 if (!(torture_random(trsp) %
178 (cxt.nrealwriters_stress * 2 * shortdelay_us)))
179 udelay(shortdelay_us);
180#ifdef CONFIG_PREEMPT
181 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
182 preempt_schedule(); /* Allow test to be preempted. */
183#endif
184}
185
186static void torture_spin_lock_write_unlock(void) __releases(torture_spinlock)
187{
188 spin_unlock(&torture_spinlock);
189}
190
191static struct lock_torture_ops spin_lock_ops = {
192 .writelock = torture_spin_lock_write_lock,
193 .write_delay = torture_spin_lock_write_delay,
194 .task_boost = torture_boost_dummy,
195 .writeunlock = torture_spin_lock_write_unlock,
196 .readlock = NULL,
197 .read_delay = NULL,
198 .readunlock = NULL,
199 .name = "spin_lock"
200};
201
202static int torture_spin_lock_write_lock_irq(void)
203__acquires(torture_spinlock)
204{
205 unsigned long flags;
206
207 spin_lock_irqsave(&torture_spinlock, flags);
208 cxt.cur_ops->flags = flags;
209 return 0;
210}
211
212static void torture_lock_spin_write_unlock_irq(void)
213__releases(torture_spinlock)
214{
215 spin_unlock_irqrestore(&torture_spinlock, cxt.cur_ops->flags);
216}
217
218static struct lock_torture_ops spin_lock_irq_ops = {
219 .writelock = torture_spin_lock_write_lock_irq,
220 .write_delay = torture_spin_lock_write_delay,
221 .task_boost = torture_boost_dummy,
222 .writeunlock = torture_lock_spin_write_unlock_irq,
223 .readlock = NULL,
224 .read_delay = NULL,
225 .readunlock = NULL,
226 .name = "spin_lock_irq"
227};
228
229static DEFINE_RWLOCK(torture_rwlock);
230
231static int torture_rwlock_write_lock(void) __acquires(torture_rwlock)
232{
233 write_lock(&torture_rwlock);
234 return 0;
235}
236
237static void torture_rwlock_write_delay(struct torture_random_state *trsp)
238{
239 const unsigned long shortdelay_us = 2;
240 const unsigned long longdelay_ms = 100;
241
242 /* We want a short delay mostly to emulate likely code, and
243 * we want a long delay occasionally to force massive contention.
244 */
245 if (!(torture_random(trsp) %
246 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
247 mdelay(longdelay_ms);
248 else
249 udelay(shortdelay_us);
250}
251
252static void torture_rwlock_write_unlock(void) __releases(torture_rwlock)
253{
254 write_unlock(&torture_rwlock);
255}
256
257static int torture_rwlock_read_lock(void) __acquires(torture_rwlock)
258{
259 read_lock(&torture_rwlock);
260 return 0;
261}
262
263static void torture_rwlock_read_delay(struct torture_random_state *trsp)
264{
265 const unsigned long shortdelay_us = 10;
266 const unsigned long longdelay_ms = 100;
267
268 /* We want a short delay mostly to emulate likely code, and
269 * we want a long delay occasionally to force massive contention.
270 */
271 if (!(torture_random(trsp) %
272 (cxt.nrealreaders_stress * 2000 * longdelay_ms)))
273 mdelay(longdelay_ms);
274 else
275 udelay(shortdelay_us);
276}
277
278static void torture_rwlock_read_unlock(void) __releases(torture_rwlock)
279{
280 read_unlock(&torture_rwlock);
281}
282
283static struct lock_torture_ops rw_lock_ops = {
284 .writelock = torture_rwlock_write_lock,
285 .write_delay = torture_rwlock_write_delay,
286 .task_boost = torture_boost_dummy,
287 .writeunlock = torture_rwlock_write_unlock,
288 .readlock = torture_rwlock_read_lock,
289 .read_delay = torture_rwlock_read_delay,
290 .readunlock = torture_rwlock_read_unlock,
291 .name = "rw_lock"
292};
293
294static int torture_rwlock_write_lock_irq(void) __acquires(torture_rwlock)
295{
296 unsigned long flags;
297
298 write_lock_irqsave(&torture_rwlock, flags);
299 cxt.cur_ops->flags = flags;
300 return 0;
301}
302
303static void torture_rwlock_write_unlock_irq(void)
304__releases(torture_rwlock)
305{
306 write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
307}
308
309static int torture_rwlock_read_lock_irq(void) __acquires(torture_rwlock)
310{
311 unsigned long flags;
312
313 read_lock_irqsave(&torture_rwlock, flags);
314 cxt.cur_ops->flags = flags;
315 return 0;
316}
317
318static void torture_rwlock_read_unlock_irq(void)
319__releases(torture_rwlock)
320{
321 read_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
322}
323
324static struct lock_torture_ops rw_lock_irq_ops = {
325 .writelock = torture_rwlock_write_lock_irq,
326 .write_delay = torture_rwlock_write_delay,
327 .task_boost = torture_boost_dummy,
328 .writeunlock = torture_rwlock_write_unlock_irq,
329 .readlock = torture_rwlock_read_lock_irq,
330 .read_delay = torture_rwlock_read_delay,
331 .readunlock = torture_rwlock_read_unlock_irq,
332 .name = "rw_lock_irq"
333};
334
335static DEFINE_MUTEX(torture_mutex);
336
337static int torture_mutex_lock(void) __acquires(torture_mutex)
338{
339 mutex_lock(&torture_mutex);
340 return 0;
341}
342
343static void torture_mutex_delay(struct torture_random_state *trsp)
344{
345 const unsigned long longdelay_ms = 100;
346
347 /* We want a long delay occasionally to force massive contention. */
348 if (!(torture_random(trsp) %
349 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
350 mdelay(longdelay_ms * 5);
351 else
352 mdelay(longdelay_ms / 5);
353#ifdef CONFIG_PREEMPT
354 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
355 preempt_schedule(); /* Allow test to be preempted. */
356#endif
357}
358
359static void torture_mutex_unlock(void) __releases(torture_mutex)
360{
361 mutex_unlock(&torture_mutex);
362}
363
364static struct lock_torture_ops mutex_lock_ops = {
365 .writelock = torture_mutex_lock,
366 .write_delay = torture_mutex_delay,
367 .task_boost = torture_boost_dummy,
368 .writeunlock = torture_mutex_unlock,
369 .readlock = NULL,
370 .read_delay = NULL,
371 .readunlock = NULL,
372 .name = "mutex_lock"
373};
374
375#ifdef CONFIG_RT_MUTEXES
376static DEFINE_RT_MUTEX(torture_rtmutex);
377
378static int torture_rtmutex_lock(void) __acquires(torture_rtmutex)
379{
380 rt_mutex_lock(&torture_rtmutex);
381 return 0;
382}
383
384static void torture_rtmutex_boost(struct torture_random_state *trsp)
385{
386 int policy;
387 struct sched_param param;
388 const unsigned int factor = 50000; /* yes, quite arbitrary */
389
390 if (!rt_task(current)) {
391 /*
392 * Boost priority once every ~50k operations. When the
393 * task tries to take the lock, the rtmutex it will account
394 * for the new priority, and do any corresponding pi-dance.
395 */
396 if (trsp && !(torture_random(trsp) %
397 (cxt.nrealwriters_stress * factor))) {
398 policy = SCHED_FIFO;
399 param.sched_priority = MAX_RT_PRIO - 1;
400 } else /* common case, do nothing */
401 return;
402 } else {
403 /*
404 * The task will remain boosted for another ~500k operations,
405 * then restored back to its original prio, and so forth.
406 *
407 * When @trsp is nil, we want to force-reset the task for
408 * stopping the kthread.
409 */
410 if (!trsp || !(torture_random(trsp) %
411 (cxt.nrealwriters_stress * factor * 2))) {
412 policy = SCHED_NORMAL;
413 param.sched_priority = 0;
414 } else /* common case, do nothing */
415 return;
416 }
417
418 sched_setscheduler_nocheck(current, policy, ¶m);
419}
420
421static void torture_rtmutex_delay(struct torture_random_state *trsp)
422{
423 const unsigned long shortdelay_us = 2;
424 const unsigned long longdelay_ms = 100;
425
426 /*
427 * We want a short delay mostly to emulate likely code, and
428 * we want a long delay occasionally to force massive contention.
429 */
430 if (!(torture_random(trsp) %
431 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
432 mdelay(longdelay_ms);
433 if (!(torture_random(trsp) %
434 (cxt.nrealwriters_stress * 2 * shortdelay_us)))
435 udelay(shortdelay_us);
436#ifdef CONFIG_PREEMPT
437 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
438 preempt_schedule(); /* Allow test to be preempted. */
439#endif
440}
441
442static void torture_rtmutex_unlock(void) __releases(torture_rtmutex)
443{
444 rt_mutex_unlock(&torture_rtmutex);
445}
446
447static struct lock_torture_ops rtmutex_lock_ops = {
448 .writelock = torture_rtmutex_lock,
449 .write_delay = torture_rtmutex_delay,
450 .task_boost = torture_rtmutex_boost,
451 .writeunlock = torture_rtmutex_unlock,
452 .readlock = NULL,
453 .read_delay = NULL,
454 .readunlock = NULL,
455 .name = "rtmutex_lock"
456};
457#endif
458
459static DECLARE_RWSEM(torture_rwsem);
460static int torture_rwsem_down_write(void) __acquires(torture_rwsem)
461{
462 down_write(&torture_rwsem);
463 return 0;
464}
465
466static void torture_rwsem_write_delay(struct torture_random_state *trsp)
467{
468 const unsigned long longdelay_ms = 100;
469
470 /* We want a long delay occasionally to force massive contention. */
471 if (!(torture_random(trsp) %
472 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
473 mdelay(longdelay_ms * 10);
474 else
475 mdelay(longdelay_ms / 10);
476#ifdef CONFIG_PREEMPT
477 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
478 preempt_schedule(); /* Allow test to be preempted. */
479#endif
480}
481
482static void torture_rwsem_up_write(void) __releases(torture_rwsem)
483{
484 up_write(&torture_rwsem);
485}
486
487static int torture_rwsem_down_read(void) __acquires(torture_rwsem)
488{
489 down_read(&torture_rwsem);
490 return 0;
491}
492
493static void torture_rwsem_read_delay(struct torture_random_state *trsp)
494{
495 const unsigned long longdelay_ms = 100;
496
497 /* We want a long delay occasionally to force massive contention. */
498 if (!(torture_random(trsp) %
499 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
500 mdelay(longdelay_ms * 2);
501 else
502 mdelay(longdelay_ms / 2);
503#ifdef CONFIG_PREEMPT
504 if (!(torture_random(trsp) % (cxt.nrealreaders_stress * 20000)))
505 preempt_schedule(); /* Allow test to be preempted. */
506#endif
507}
508
509static void torture_rwsem_up_read(void) __releases(torture_rwsem)
510{
511 up_read(&torture_rwsem);
512}
513
514static struct lock_torture_ops rwsem_lock_ops = {
515 .writelock = torture_rwsem_down_write,
516 .write_delay = torture_rwsem_write_delay,
517 .task_boost = torture_boost_dummy,
518 .writeunlock = torture_rwsem_up_write,
519 .readlock = torture_rwsem_down_read,
520 .read_delay = torture_rwsem_read_delay,
521 .readunlock = torture_rwsem_up_read,
522 .name = "rwsem_lock"
523};
524
525#include <linux/percpu-rwsem.h>
526static struct percpu_rw_semaphore pcpu_rwsem;
527
528void torture_percpu_rwsem_init(void)
529{
530 BUG_ON(percpu_init_rwsem(&pcpu_rwsem));
531}
532
533static int torture_percpu_rwsem_down_write(void) __acquires(pcpu_rwsem)
534{
535 percpu_down_write(&pcpu_rwsem);
536 return 0;
537}
538
539static void torture_percpu_rwsem_up_write(void) __releases(pcpu_rwsem)
540{
541 percpu_up_write(&pcpu_rwsem);
542}
543
544static int torture_percpu_rwsem_down_read(void) __acquires(pcpu_rwsem)
545{
546 percpu_down_read(&pcpu_rwsem);
547 return 0;
548}
549
550static void torture_percpu_rwsem_up_read(void) __releases(pcpu_rwsem)
551{
552 percpu_up_read(&pcpu_rwsem);
553}
554
555static struct lock_torture_ops percpu_rwsem_lock_ops = {
556 .init = torture_percpu_rwsem_init,
557 .writelock = torture_percpu_rwsem_down_write,
558 .write_delay = torture_rwsem_write_delay,
559 .task_boost = torture_boost_dummy,
560 .writeunlock = torture_percpu_rwsem_up_write,
561 .readlock = torture_percpu_rwsem_down_read,
562 .read_delay = torture_rwsem_read_delay,
563 .readunlock = torture_percpu_rwsem_up_read,
564 .name = "percpu_rwsem_lock"
565};
566
567/*
568 * Lock torture writer kthread. Repeatedly acquires and releases
569 * the lock, checking for duplicate acquisitions.
570 */
571static int lock_torture_writer(void *arg)
572{
573 struct lock_stress_stats *lwsp = arg;
574 static DEFINE_TORTURE_RANDOM(rand);
575
576 VERBOSE_TOROUT_STRING("lock_torture_writer task started");
577 set_user_nice(current, MAX_NICE);
578
579 do {
580 if ((torture_random(&rand) & 0xfffff) == 0)
581 schedule_timeout_uninterruptible(1);
582
583 cxt.cur_ops->task_boost(&rand);
584 cxt.cur_ops->writelock();
585 if (WARN_ON_ONCE(lock_is_write_held))
586 lwsp->n_lock_fail++;
587 lock_is_write_held = 1;
588 if (WARN_ON_ONCE(lock_is_read_held))
589 lwsp->n_lock_fail++; /* rare, but... */
590
591 lwsp->n_lock_acquired++;
592 cxt.cur_ops->write_delay(&rand);
593 lock_is_write_held = 0;
594 cxt.cur_ops->writeunlock();
595
596 stutter_wait("lock_torture_writer");
597 } while (!torture_must_stop());
598
599 cxt.cur_ops->task_boost(NULL); /* reset prio */
600 torture_kthread_stopping("lock_torture_writer");
601 return 0;
602}
603
604/*
605 * Lock torture reader kthread. Repeatedly acquires and releases
606 * the reader lock.
607 */
608static int lock_torture_reader(void *arg)
609{
610 struct lock_stress_stats *lrsp = arg;
611 static DEFINE_TORTURE_RANDOM(rand);
612
613 VERBOSE_TOROUT_STRING("lock_torture_reader task started");
614 set_user_nice(current, MAX_NICE);
615
616 do {
617 if ((torture_random(&rand) & 0xfffff) == 0)
618 schedule_timeout_uninterruptible(1);
619
620 cxt.cur_ops->readlock();
621 lock_is_read_held = 1;
622 if (WARN_ON_ONCE(lock_is_write_held))
623 lrsp->n_lock_fail++; /* rare, but... */
624
625 lrsp->n_lock_acquired++;
626 cxt.cur_ops->read_delay(&rand);
627 lock_is_read_held = 0;
628 cxt.cur_ops->readunlock();
629
630 stutter_wait("lock_torture_reader");
631 } while (!torture_must_stop());
632 torture_kthread_stopping("lock_torture_reader");
633 return 0;
634}
635
636/*
637 * Create an lock-torture-statistics message in the specified buffer.
638 */
639static void __torture_print_stats(char *page,
640 struct lock_stress_stats *statp, bool write)
641{
642 bool fail = 0;
643 int i, n_stress;
644 long max = 0;
645 long min = statp[0].n_lock_acquired;
646 long long sum = 0;
647
648 n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress;
649 for (i = 0; i < n_stress; i++) {
650 if (statp[i].n_lock_fail)
651 fail = true;
652 sum += statp[i].n_lock_acquired;
653 if (max < statp[i].n_lock_fail)
654 max = statp[i].n_lock_fail;
655 if (min > statp[i].n_lock_fail)
656 min = statp[i].n_lock_fail;
657 }
658 page += sprintf(page,
659 "%s: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n",
660 write ? "Writes" : "Reads ",
661 sum, max, min, max / 2 > min ? "???" : "",
662 fail, fail ? "!!!" : "");
663 if (fail)
664 atomic_inc(&cxt.n_lock_torture_errors);
665}
666
667/*
668 * Print torture statistics. Caller must ensure that there is only one
669 * call to this function at a given time!!! This is normally accomplished
670 * by relying on the module system to only have one copy of the module
671 * loaded, and then by giving the lock_torture_stats kthread full control
672 * (or the init/cleanup functions when lock_torture_stats thread is not
673 * running).
674 */
675static void lock_torture_stats_print(void)
676{
677 int size = cxt.nrealwriters_stress * 200 + 8192;
678 char *buf;
679
680 if (cxt.cur_ops->readlock)
681 size += cxt.nrealreaders_stress * 200 + 8192;
682
683 buf = kmalloc(size, GFP_KERNEL);
684 if (!buf) {
685 pr_err("lock_torture_stats_print: Out of memory, need: %d",
686 size);
687 return;
688 }
689
690 __torture_print_stats(buf, cxt.lwsa, true);
691 pr_alert("%s", buf);
692 kfree(buf);
693
694 if (cxt.cur_ops->readlock) {
695 buf = kmalloc(size, GFP_KERNEL);
696 if (!buf) {
697 pr_err("lock_torture_stats_print: Out of memory, need: %d",
698 size);
699 return;
700 }
701
702 __torture_print_stats(buf, cxt.lrsa, false);
703 pr_alert("%s", buf);
704 kfree(buf);
705 }
706}
707
708/*
709 * Periodically prints torture statistics, if periodic statistics printing
710 * was specified via the stat_interval module parameter.
711 *
712 * No need to worry about fullstop here, since this one doesn't reference
713 * volatile state or register callbacks.
714 */
715static int lock_torture_stats(void *arg)
716{
717 VERBOSE_TOROUT_STRING("lock_torture_stats task started");
718 do {
719 schedule_timeout_interruptible(stat_interval * HZ);
720 lock_torture_stats_print();
721 torture_shutdown_absorb("lock_torture_stats");
722 } while (!torture_must_stop());
723 torture_kthread_stopping("lock_torture_stats");
724 return 0;
725}
726
727static inline void
728lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
729 const char *tag)
730{
731 pr_alert("%s" TORTURE_FLAG
732 "--- %s%s: nwriters_stress=%d nreaders_stress=%d stat_interval=%d verbose=%d shuffle_interval=%d stutter=%d shutdown_secs=%d onoff_interval=%d onoff_holdoff=%d\n",
733 torture_type, tag, cxt.debug_lock ? " [debug]": "",
734 cxt.nrealwriters_stress, cxt.nrealreaders_stress, stat_interval,
735 verbose, shuffle_interval, stutter, shutdown_secs,
736 onoff_interval, onoff_holdoff);
737}
738
739static void lock_torture_cleanup(void)
740{
741 int i;
742
743 if (torture_cleanup_begin())
744 return;
745
746 /*
747 * Indicates early cleanup, meaning that the test has not run,
748 * such as when passing bogus args when loading the module. As
749 * such, only perform the underlying torture-specific cleanups,
750 * and avoid anything related to locktorture.
751 */
752 if (!cxt.lwsa)
753 goto end;
754
755 if (writer_tasks) {
756 for (i = 0; i < cxt.nrealwriters_stress; i++)
757 torture_stop_kthread(lock_torture_writer,
758 writer_tasks[i]);
759 kfree(writer_tasks);
760 writer_tasks = NULL;
761 }
762
763 if (reader_tasks) {
764 for (i = 0; i < cxt.nrealreaders_stress; i++)
765 torture_stop_kthread(lock_torture_reader,
766 reader_tasks[i]);
767 kfree(reader_tasks);
768 reader_tasks = NULL;
769 }
770
771 torture_stop_kthread(lock_torture_stats, stats_task);
772 lock_torture_stats_print(); /* -After- the stats thread is stopped! */
773
774 if (atomic_read(&cxt.n_lock_torture_errors))
775 lock_torture_print_module_parms(cxt.cur_ops,
776 "End of test: FAILURE");
777 else if (torture_onoff_failures())
778 lock_torture_print_module_parms(cxt.cur_ops,
779 "End of test: LOCK_HOTPLUG");
780 else
781 lock_torture_print_module_parms(cxt.cur_ops,
782 "End of test: SUCCESS");
783end:
784 torture_cleanup_end();
785}
786
787static int __init lock_torture_init(void)
788{
789 int i, j;
790 int firsterr = 0;
791 static struct lock_torture_ops *torture_ops[] = {
792 &lock_busted_ops,
793 &spin_lock_ops, &spin_lock_irq_ops,
794 &rw_lock_ops, &rw_lock_irq_ops,
795 &mutex_lock_ops,
796#ifdef CONFIG_RT_MUTEXES
797 &rtmutex_lock_ops,
798#endif
799 &rwsem_lock_ops,
800 &percpu_rwsem_lock_ops,
801 };
802
803 if (!torture_init_begin(torture_type, verbose, &torture_runnable))
804 return -EBUSY;
805
806 /* Process args and tell the world that the torturer is on the job. */
807 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
808 cxt.cur_ops = torture_ops[i];
809 if (strcmp(torture_type, cxt.cur_ops->name) == 0)
810 break;
811 }
812 if (i == ARRAY_SIZE(torture_ops)) {
813 pr_alert("lock-torture: invalid torture type: \"%s\"\n",
814 torture_type);
815 pr_alert("lock-torture types:");
816 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
817 pr_alert(" %s", torture_ops[i]->name);
818 pr_alert("\n");
819 firsterr = -EINVAL;
820 goto unwind;
821 }
822 if (cxt.cur_ops->init)
823 cxt.cur_ops->init();
824
825 if (nwriters_stress >= 0)
826 cxt.nrealwriters_stress = nwriters_stress;
827 else
828 cxt.nrealwriters_stress = 2 * num_online_cpus();
829
830#ifdef CONFIG_DEBUG_MUTEXES
831 if (strncmp(torture_type, "mutex", 5) == 0)
832 cxt.debug_lock = true;
833#endif
834#ifdef CONFIG_DEBUG_RT_MUTEXES
835 if (strncmp(torture_type, "rtmutex", 7) == 0)
836 cxt.debug_lock = true;
837#endif
838#ifdef CONFIG_DEBUG_SPINLOCK
839 if ((strncmp(torture_type, "spin", 4) == 0) ||
840 (strncmp(torture_type, "rw_lock", 7) == 0))
841 cxt.debug_lock = true;
842#endif
843
844 /* Initialize the statistics so that each run gets its own numbers. */
845
846 lock_is_write_held = 0;
847 cxt.lwsa = kmalloc(sizeof(*cxt.lwsa) * cxt.nrealwriters_stress, GFP_KERNEL);
848 if (cxt.lwsa == NULL) {
849 VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory");
850 firsterr = -ENOMEM;
851 goto unwind;
852 }
853 for (i = 0; i < cxt.nrealwriters_stress; i++) {
854 cxt.lwsa[i].n_lock_fail = 0;
855 cxt.lwsa[i].n_lock_acquired = 0;
856 }
857
858 if (cxt.cur_ops->readlock) {
859 if (nreaders_stress >= 0)
860 cxt.nrealreaders_stress = nreaders_stress;
861 else {
862 /*
863 * By default distribute evenly the number of
864 * readers and writers. We still run the same number
865 * of threads as the writer-only locks default.
866 */
867 if (nwriters_stress < 0) /* user doesn't care */
868 cxt.nrealwriters_stress = num_online_cpus();
869 cxt.nrealreaders_stress = cxt.nrealwriters_stress;
870 }
871
872 lock_is_read_held = 0;
873 cxt.lrsa = kmalloc(sizeof(*cxt.lrsa) * cxt.nrealreaders_stress, GFP_KERNEL);
874 if (cxt.lrsa == NULL) {
875 VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory");
876 firsterr = -ENOMEM;
877 kfree(cxt.lwsa);
878 cxt.lwsa = NULL;
879 goto unwind;
880 }
881
882 for (i = 0; i < cxt.nrealreaders_stress; i++) {
883 cxt.lrsa[i].n_lock_fail = 0;
884 cxt.lrsa[i].n_lock_acquired = 0;
885 }
886 }
887
888 lock_torture_print_module_parms(cxt.cur_ops, "Start of test");
889
890 /* Prepare torture context. */
891 if (onoff_interval > 0) {
892 firsterr = torture_onoff_init(onoff_holdoff * HZ,
893 onoff_interval * HZ);
894 if (firsterr)
895 goto unwind;
896 }
897 if (shuffle_interval > 0) {
898 firsterr = torture_shuffle_init(shuffle_interval);
899 if (firsterr)
900 goto unwind;
901 }
902 if (shutdown_secs > 0) {
903 firsterr = torture_shutdown_init(shutdown_secs,
904 lock_torture_cleanup);
905 if (firsterr)
906 goto unwind;
907 }
908 if (stutter > 0) {
909 firsterr = torture_stutter_init(stutter);
910 if (firsterr)
911 goto unwind;
912 }
913
914 writer_tasks = kzalloc(cxt.nrealwriters_stress * sizeof(writer_tasks[0]),
915 GFP_KERNEL);
916 if (writer_tasks == NULL) {
917 VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory");
918 firsterr = -ENOMEM;
919 goto unwind;
920 }
921
922 if (cxt.cur_ops->readlock) {
923 reader_tasks = kzalloc(cxt.nrealreaders_stress * sizeof(reader_tasks[0]),
924 GFP_KERNEL);
925 if (reader_tasks == NULL) {
926 VERBOSE_TOROUT_ERRSTRING("reader_tasks: Out of memory");
927 firsterr = -ENOMEM;
928 goto unwind;
929 }
930 }
931
932 /*
933 * Create the kthreads and start torturing (oh, those poor little locks).
934 *
935 * TODO: Note that we interleave writers with readers, giving writers a
936 * slight advantage, by creating its kthread first. This can be modified
937 * for very specific needs, or even let the user choose the policy, if
938 * ever wanted.
939 */
940 for (i = 0, j = 0; i < cxt.nrealwriters_stress ||
941 j < cxt.nrealreaders_stress; i++, j++) {
942 if (i >= cxt.nrealwriters_stress)
943 goto create_reader;
944
945 /* Create writer. */
946 firsterr = torture_create_kthread(lock_torture_writer, &cxt.lwsa[i],
947 writer_tasks[i]);
948 if (firsterr)
949 goto unwind;
950
951 create_reader:
952 if (cxt.cur_ops->readlock == NULL || (j >= cxt.nrealreaders_stress))
953 continue;
954 /* Create reader. */
955 firsterr = torture_create_kthread(lock_torture_reader, &cxt.lrsa[j],
956 reader_tasks[j]);
957 if (firsterr)
958 goto unwind;
959 }
960 if (stat_interval > 0) {
961 firsterr = torture_create_kthread(lock_torture_stats, NULL,
962 stats_task);
963 if (firsterr)
964 goto unwind;
965 }
966 torture_init_end();
967 return 0;
968
969unwind:
970 torture_init_end();
971 lock_torture_cleanup();
972 return firsterr;
973}
974
975module_init(lock_torture_init);
976module_exit(lock_torture_cleanup);