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