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