Loading...
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Module-based torture test facility for locking
4 *
5 * Copyright (C) IBM Corporation, 2014
6 *
7 * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
8 * Davidlohr Bueso <dave@stgolabs.net>
9 * Based on kernel/rcu/torture.c.
10 */
11
12#define pr_fmt(fmt) fmt
13
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/kthread.h>
17#include <linux/sched/rt.h>
18#include <linux/spinlock.h>
19#include <linux/mutex.h>
20#include <linux/rwsem.h>
21#include <linux/smp.h>
22#include <linux/interrupt.h>
23#include <linux/sched.h>
24#include <uapi/linux/sched/types.h>
25#include <linux/rtmutex.h>
26#include <linux/atomic.h>
27#include <linux/moduleparam.h>
28#include <linux/delay.h>
29#include <linux/slab.h>
30#include <linux/torture.h>
31#include <linux/reboot.h>
32
33MODULE_LICENSE("GPL");
34MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>");
35
36torture_param(int, acq_writer_lim, 0, "Write_acquisition time limit (jiffies).");
37torture_param(int, call_rcu_chains, 0, "Self-propagate call_rcu() chains during test (0=disable).");
38torture_param(int, long_hold, 100, "Do occasional long hold of lock (ms), 0=disable");
39torture_param(int, nested_locks, 0, "Number of nested locks (max = 8)");
40torture_param(int, nreaders_stress, -1, "Number of read-locking stress-test threads");
41torture_param(int, nwriters_stress, -1, "Number of write-locking stress-test threads");
42torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
43torture_param(int, onoff_interval, 0, "Time between CPU hotplugs (s), 0=disable");
44torture_param(int, rt_boost, 2,
45 "Do periodic rt-boost. 0=Disable, 1=Only for rt_mutex, 2=For all lock types.");
46torture_param(int, rt_boost_factor, 50, "A factor determining how often rt-boost happens.");
47torture_param(int, shuffle_interval, 3, "Number of jiffies between shuffles, 0=disable");
48torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable.");
49torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s");
50torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
51torture_param(int, verbose, 1, "Enable verbose debugging printk()s");
52torture_param(int, writer_fifo, 0, "Run writers at sched_set_fifo() priority");
53/* Going much higher trips "BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!" errors */
54#define MAX_NESTED_LOCKS 8
55
56static char *torture_type = IS_ENABLED(CONFIG_PREEMPT_RT) ? "raw_spin_lock" : "spin_lock";
57module_param(torture_type, charp, 0444);
58MODULE_PARM_DESC(torture_type,
59 "Type of lock to torture (spin_lock, spin_lock_irq, mutex_lock, ...)");
60
61static cpumask_var_t bind_readers; // Bind the readers to the specified set of CPUs.
62static cpumask_var_t bind_writers; // Bind the writers to the specified set of CPUs.
63
64// Parse a cpumask kernel parameter. If there are more users later on,
65// this might need to got to a more central location.
66static int param_set_cpumask(const char *val, const struct kernel_param *kp)
67{
68 cpumask_var_t *cm_bind = kp->arg;
69 int ret;
70 char *s;
71
72 if (!alloc_cpumask_var(cm_bind, GFP_KERNEL)) {
73 s = "Out of memory";
74 ret = -ENOMEM;
75 goto out_err;
76 }
77 ret = cpulist_parse(val, *cm_bind);
78 if (!ret)
79 return ret;
80 s = "Bad CPU range";
81out_err:
82 pr_warn("%s: %s, all CPUs set\n", kp->name, s);
83 cpumask_setall(*cm_bind);
84 return ret;
85}
86
87// Output a cpumask kernel parameter.
88static int param_get_cpumask(char *buffer, const struct kernel_param *kp)
89{
90 cpumask_var_t *cm_bind = kp->arg;
91
92 return sprintf(buffer, "%*pbl", cpumask_pr_args(*cm_bind));
93}
94
95static bool cpumask_nonempty(cpumask_var_t mask)
96{
97 return cpumask_available(mask) && !cpumask_empty(mask);
98}
99
100static const struct kernel_param_ops lt_bind_ops = {
101 .set = param_set_cpumask,
102 .get = param_get_cpumask,
103};
104
105module_param_cb(bind_readers, <_bind_ops, &bind_readers, 0644);
106module_param_cb(bind_writers, <_bind_ops, &bind_writers, 0644);
107
108long torture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask);
109
110static struct task_struct *stats_task;
111static struct task_struct **writer_tasks;
112static struct task_struct **reader_tasks;
113
114static bool lock_is_write_held;
115static atomic_t lock_is_read_held;
116static unsigned long last_lock_release;
117
118struct lock_stress_stats {
119 long n_lock_fail;
120 long n_lock_acquired;
121};
122
123struct call_rcu_chain {
124 struct rcu_head crc_rh;
125 bool crc_stop;
126};
127struct call_rcu_chain *call_rcu_chain_list;
128
129/* Forward reference. */
130static void lock_torture_cleanup(void);
131
132/*
133 * Operations vector for selecting different types of tests.
134 */
135struct lock_torture_ops {
136 void (*init)(void);
137 void (*exit)(void);
138 int (*nested_lock)(int tid, u32 lockset);
139 int (*writelock)(int tid);
140 void (*write_delay)(struct torture_random_state *trsp);
141 void (*task_boost)(struct torture_random_state *trsp);
142 void (*writeunlock)(int tid);
143 void (*nested_unlock)(int tid, u32 lockset);
144 int (*readlock)(int tid);
145 void (*read_delay)(struct torture_random_state *trsp);
146 void (*readunlock)(int tid);
147
148 unsigned long flags; /* for irq spinlocks */
149 const char *name;
150};
151
152struct lock_torture_cxt {
153 int nrealwriters_stress;
154 int nrealreaders_stress;
155 bool debug_lock;
156 bool init_called;
157 atomic_t n_lock_torture_errors;
158 struct lock_torture_ops *cur_ops;
159 struct lock_stress_stats *lwsa; /* writer statistics */
160 struct lock_stress_stats *lrsa; /* reader statistics */
161};
162static struct lock_torture_cxt cxt = { 0, 0, false, false,
163 ATOMIC_INIT(0),
164 NULL, NULL};
165/*
166 * Definitions for lock torture testing.
167 */
168
169static int torture_lock_busted_write_lock(int tid __maybe_unused)
170{
171 return 0; /* BUGGY, do not use in real life!!! */
172}
173
174static void torture_lock_busted_write_delay(struct torture_random_state *trsp)
175{
176 /* We want a long delay occasionally to force massive contention. */
177 if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold)))
178 mdelay(long_hold);
179 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
180 torture_preempt_schedule(); /* Allow test to be preempted. */
181}
182
183static void torture_lock_busted_write_unlock(int tid __maybe_unused)
184{
185 /* BUGGY, do not use in real life!!! */
186}
187
188static void __torture_rt_boost(struct torture_random_state *trsp)
189{
190 const unsigned int factor = rt_boost_factor;
191
192 if (!rt_task(current)) {
193 /*
194 * Boost priority once every rt_boost_factor operations. When
195 * the task tries to take the lock, the rtmutex it will account
196 * for the new priority, and do any corresponding pi-dance.
197 */
198 if (trsp && !(torture_random(trsp) %
199 (cxt.nrealwriters_stress * factor))) {
200 sched_set_fifo(current);
201 } else /* common case, do nothing */
202 return;
203 } else {
204 /*
205 * The task will remain boosted for another 10 * rt_boost_factor
206 * operations, then restored back to its original prio, and so
207 * forth.
208 *
209 * When @trsp is nil, we want to force-reset the task for
210 * stopping the kthread.
211 */
212 if (!trsp || !(torture_random(trsp) %
213 (cxt.nrealwriters_stress * factor * 2))) {
214 sched_set_normal(current, 0);
215 } else /* common case, do nothing */
216 return;
217 }
218}
219
220static void torture_rt_boost(struct torture_random_state *trsp)
221{
222 if (rt_boost != 2)
223 return;
224
225 __torture_rt_boost(trsp);
226}
227
228static struct lock_torture_ops lock_busted_ops = {
229 .writelock = torture_lock_busted_write_lock,
230 .write_delay = torture_lock_busted_write_delay,
231 .task_boost = torture_rt_boost,
232 .writeunlock = torture_lock_busted_write_unlock,
233 .readlock = NULL,
234 .read_delay = NULL,
235 .readunlock = NULL,
236 .name = "lock_busted"
237};
238
239static DEFINE_SPINLOCK(torture_spinlock);
240
241static int torture_spin_lock_write_lock(int tid __maybe_unused)
242__acquires(torture_spinlock)
243{
244 spin_lock(&torture_spinlock);
245 return 0;
246}
247
248static void torture_spin_lock_write_delay(struct torture_random_state *trsp)
249{
250 const unsigned long shortdelay_us = 2;
251 unsigned long j;
252
253 /* We want a short delay mostly to emulate likely code, and
254 * we want a long delay occasionally to force massive contention.
255 */
256 if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold))) {
257 j = jiffies;
258 mdelay(long_hold);
259 pr_alert("%s: delay = %lu jiffies.\n", __func__, jiffies - j);
260 }
261 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 200 * shortdelay_us)))
262 udelay(shortdelay_us);
263 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
264 torture_preempt_schedule(); /* Allow test to be preempted. */
265}
266
267static void torture_spin_lock_write_unlock(int tid __maybe_unused)
268__releases(torture_spinlock)
269{
270 spin_unlock(&torture_spinlock);
271}
272
273static struct lock_torture_ops spin_lock_ops = {
274 .writelock = torture_spin_lock_write_lock,
275 .write_delay = torture_spin_lock_write_delay,
276 .task_boost = torture_rt_boost,
277 .writeunlock = torture_spin_lock_write_unlock,
278 .readlock = NULL,
279 .read_delay = NULL,
280 .readunlock = NULL,
281 .name = "spin_lock"
282};
283
284static int torture_spin_lock_write_lock_irq(int tid __maybe_unused)
285__acquires(torture_spinlock)
286{
287 unsigned long flags;
288
289 spin_lock_irqsave(&torture_spinlock, flags);
290 cxt.cur_ops->flags = flags;
291 return 0;
292}
293
294static void torture_lock_spin_write_unlock_irq(int tid __maybe_unused)
295__releases(torture_spinlock)
296{
297 spin_unlock_irqrestore(&torture_spinlock, cxt.cur_ops->flags);
298}
299
300static struct lock_torture_ops spin_lock_irq_ops = {
301 .writelock = torture_spin_lock_write_lock_irq,
302 .write_delay = torture_spin_lock_write_delay,
303 .task_boost = torture_rt_boost,
304 .writeunlock = torture_lock_spin_write_unlock_irq,
305 .readlock = NULL,
306 .read_delay = NULL,
307 .readunlock = NULL,
308 .name = "spin_lock_irq"
309};
310
311static DEFINE_RAW_SPINLOCK(torture_raw_spinlock);
312
313static int torture_raw_spin_lock_write_lock(int tid __maybe_unused)
314__acquires(torture_raw_spinlock)
315{
316 raw_spin_lock(&torture_raw_spinlock);
317 return 0;
318}
319
320static void torture_raw_spin_lock_write_unlock(int tid __maybe_unused)
321__releases(torture_raw_spinlock)
322{
323 raw_spin_unlock(&torture_raw_spinlock);
324}
325
326static struct lock_torture_ops raw_spin_lock_ops = {
327 .writelock = torture_raw_spin_lock_write_lock,
328 .write_delay = torture_spin_lock_write_delay,
329 .task_boost = torture_rt_boost,
330 .writeunlock = torture_raw_spin_lock_write_unlock,
331 .readlock = NULL,
332 .read_delay = NULL,
333 .readunlock = NULL,
334 .name = "raw_spin_lock"
335};
336
337static int torture_raw_spin_lock_write_lock_irq(int tid __maybe_unused)
338__acquires(torture_raw_spinlock)
339{
340 unsigned long flags;
341
342 raw_spin_lock_irqsave(&torture_raw_spinlock, flags);
343 cxt.cur_ops->flags = flags;
344 return 0;
345}
346
347static void torture_raw_spin_lock_write_unlock_irq(int tid __maybe_unused)
348__releases(torture_raw_spinlock)
349{
350 raw_spin_unlock_irqrestore(&torture_raw_spinlock, cxt.cur_ops->flags);
351}
352
353static struct lock_torture_ops raw_spin_lock_irq_ops = {
354 .writelock = torture_raw_spin_lock_write_lock_irq,
355 .write_delay = torture_spin_lock_write_delay,
356 .task_boost = torture_rt_boost,
357 .writeunlock = torture_raw_spin_lock_write_unlock_irq,
358 .readlock = NULL,
359 .read_delay = NULL,
360 .readunlock = NULL,
361 .name = "raw_spin_lock_irq"
362};
363
364static DEFINE_RWLOCK(torture_rwlock);
365
366static int torture_rwlock_write_lock(int tid __maybe_unused)
367__acquires(torture_rwlock)
368{
369 write_lock(&torture_rwlock);
370 return 0;
371}
372
373static void torture_rwlock_write_delay(struct torture_random_state *trsp)
374{
375 const unsigned long shortdelay_us = 2;
376
377 /* We want a short delay mostly to emulate likely code, and
378 * we want a long delay occasionally to force massive contention.
379 */
380 if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold)))
381 mdelay(long_hold);
382 else
383 udelay(shortdelay_us);
384}
385
386static void torture_rwlock_write_unlock(int tid __maybe_unused)
387__releases(torture_rwlock)
388{
389 write_unlock(&torture_rwlock);
390}
391
392static int torture_rwlock_read_lock(int tid __maybe_unused)
393__acquires(torture_rwlock)
394{
395 read_lock(&torture_rwlock);
396 return 0;
397}
398
399static void torture_rwlock_read_delay(struct torture_random_state *trsp)
400{
401 const unsigned long shortdelay_us = 10;
402
403 /* We want a short delay mostly to emulate likely code, and
404 * we want a long delay occasionally to force massive contention.
405 */
406 if (long_hold && !(torture_random(trsp) % (cxt.nrealreaders_stress * 2000 * long_hold)))
407 mdelay(long_hold);
408 else
409 udelay(shortdelay_us);
410}
411
412static void torture_rwlock_read_unlock(int tid __maybe_unused)
413__releases(torture_rwlock)
414{
415 read_unlock(&torture_rwlock);
416}
417
418static struct lock_torture_ops rw_lock_ops = {
419 .writelock = torture_rwlock_write_lock,
420 .write_delay = torture_rwlock_write_delay,
421 .task_boost = torture_rt_boost,
422 .writeunlock = torture_rwlock_write_unlock,
423 .readlock = torture_rwlock_read_lock,
424 .read_delay = torture_rwlock_read_delay,
425 .readunlock = torture_rwlock_read_unlock,
426 .name = "rw_lock"
427};
428
429static int torture_rwlock_write_lock_irq(int tid __maybe_unused)
430__acquires(torture_rwlock)
431{
432 unsigned long flags;
433
434 write_lock_irqsave(&torture_rwlock, flags);
435 cxt.cur_ops->flags = flags;
436 return 0;
437}
438
439static void torture_rwlock_write_unlock_irq(int tid __maybe_unused)
440__releases(torture_rwlock)
441{
442 write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
443}
444
445static int torture_rwlock_read_lock_irq(int tid __maybe_unused)
446__acquires(torture_rwlock)
447{
448 unsigned long flags;
449
450 read_lock_irqsave(&torture_rwlock, flags);
451 cxt.cur_ops->flags = flags;
452 return 0;
453}
454
455static void torture_rwlock_read_unlock_irq(int tid __maybe_unused)
456__releases(torture_rwlock)
457{
458 read_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
459}
460
461static struct lock_torture_ops rw_lock_irq_ops = {
462 .writelock = torture_rwlock_write_lock_irq,
463 .write_delay = torture_rwlock_write_delay,
464 .task_boost = torture_rt_boost,
465 .writeunlock = torture_rwlock_write_unlock_irq,
466 .readlock = torture_rwlock_read_lock_irq,
467 .read_delay = torture_rwlock_read_delay,
468 .readunlock = torture_rwlock_read_unlock_irq,
469 .name = "rw_lock_irq"
470};
471
472static DEFINE_MUTEX(torture_mutex);
473static struct mutex torture_nested_mutexes[MAX_NESTED_LOCKS];
474static struct lock_class_key nested_mutex_keys[MAX_NESTED_LOCKS];
475
476static void torture_mutex_init(void)
477{
478 int i;
479
480 for (i = 0; i < MAX_NESTED_LOCKS; i++)
481 __mutex_init(&torture_nested_mutexes[i], __func__,
482 &nested_mutex_keys[i]);
483}
484
485static int torture_mutex_nested_lock(int tid __maybe_unused,
486 u32 lockset)
487{
488 int i;
489
490 for (i = 0; i < nested_locks; i++)
491 if (lockset & (1 << i))
492 mutex_lock(&torture_nested_mutexes[i]);
493 return 0;
494}
495
496static int torture_mutex_lock(int tid __maybe_unused)
497__acquires(torture_mutex)
498{
499 mutex_lock(&torture_mutex);
500 return 0;
501}
502
503static void torture_mutex_delay(struct torture_random_state *trsp)
504{
505 /* We want a long delay occasionally to force massive contention. */
506 if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold)))
507 mdelay(long_hold * 5);
508 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
509 torture_preempt_schedule(); /* Allow test to be preempted. */
510}
511
512static void torture_mutex_unlock(int tid __maybe_unused)
513__releases(torture_mutex)
514{
515 mutex_unlock(&torture_mutex);
516}
517
518static void torture_mutex_nested_unlock(int tid __maybe_unused,
519 u32 lockset)
520{
521 int i;
522
523 for (i = nested_locks - 1; i >= 0; i--)
524 if (lockset & (1 << i))
525 mutex_unlock(&torture_nested_mutexes[i]);
526}
527
528static struct lock_torture_ops mutex_lock_ops = {
529 .init = torture_mutex_init,
530 .nested_lock = torture_mutex_nested_lock,
531 .writelock = torture_mutex_lock,
532 .write_delay = torture_mutex_delay,
533 .task_boost = torture_rt_boost,
534 .writeunlock = torture_mutex_unlock,
535 .nested_unlock = torture_mutex_nested_unlock,
536 .readlock = NULL,
537 .read_delay = NULL,
538 .readunlock = NULL,
539 .name = "mutex_lock"
540};
541
542#include <linux/ww_mutex.h>
543/*
544 * The torture ww_mutexes should belong to the same lock class as
545 * torture_ww_class to avoid lockdep problem. The ww_mutex_init()
546 * function is called for initialization to ensure that.
547 */
548static DEFINE_WD_CLASS(torture_ww_class);
549static struct ww_mutex torture_ww_mutex_0, torture_ww_mutex_1, torture_ww_mutex_2;
550static struct ww_acquire_ctx *ww_acquire_ctxs;
551
552static void torture_ww_mutex_init(void)
553{
554 ww_mutex_init(&torture_ww_mutex_0, &torture_ww_class);
555 ww_mutex_init(&torture_ww_mutex_1, &torture_ww_class);
556 ww_mutex_init(&torture_ww_mutex_2, &torture_ww_class);
557
558 ww_acquire_ctxs = kmalloc_array(cxt.nrealwriters_stress,
559 sizeof(*ww_acquire_ctxs),
560 GFP_KERNEL);
561 if (!ww_acquire_ctxs)
562 VERBOSE_TOROUT_STRING("ww_acquire_ctx: Out of memory");
563}
564
565static void torture_ww_mutex_exit(void)
566{
567 kfree(ww_acquire_ctxs);
568}
569
570static int torture_ww_mutex_lock(int tid)
571__acquires(torture_ww_mutex_0)
572__acquires(torture_ww_mutex_1)
573__acquires(torture_ww_mutex_2)
574{
575 LIST_HEAD(list);
576 struct reorder_lock {
577 struct list_head link;
578 struct ww_mutex *lock;
579 } locks[3], *ll, *ln;
580 struct ww_acquire_ctx *ctx = &ww_acquire_ctxs[tid];
581
582 locks[0].lock = &torture_ww_mutex_0;
583 list_add(&locks[0].link, &list);
584
585 locks[1].lock = &torture_ww_mutex_1;
586 list_add(&locks[1].link, &list);
587
588 locks[2].lock = &torture_ww_mutex_2;
589 list_add(&locks[2].link, &list);
590
591 ww_acquire_init(ctx, &torture_ww_class);
592
593 list_for_each_entry(ll, &list, link) {
594 int err;
595
596 err = ww_mutex_lock(ll->lock, ctx);
597 if (!err)
598 continue;
599
600 ln = ll;
601 list_for_each_entry_continue_reverse(ln, &list, link)
602 ww_mutex_unlock(ln->lock);
603
604 if (err != -EDEADLK)
605 return err;
606
607 ww_mutex_lock_slow(ll->lock, ctx);
608 list_move(&ll->link, &list);
609 }
610
611 return 0;
612}
613
614static void torture_ww_mutex_unlock(int tid)
615__releases(torture_ww_mutex_0)
616__releases(torture_ww_mutex_1)
617__releases(torture_ww_mutex_2)
618{
619 struct ww_acquire_ctx *ctx = &ww_acquire_ctxs[tid];
620
621 ww_mutex_unlock(&torture_ww_mutex_0);
622 ww_mutex_unlock(&torture_ww_mutex_1);
623 ww_mutex_unlock(&torture_ww_mutex_2);
624 ww_acquire_fini(ctx);
625}
626
627static struct lock_torture_ops ww_mutex_lock_ops = {
628 .init = torture_ww_mutex_init,
629 .exit = torture_ww_mutex_exit,
630 .writelock = torture_ww_mutex_lock,
631 .write_delay = torture_mutex_delay,
632 .task_boost = torture_rt_boost,
633 .writeunlock = torture_ww_mutex_unlock,
634 .readlock = NULL,
635 .read_delay = NULL,
636 .readunlock = NULL,
637 .name = "ww_mutex_lock"
638};
639
640#ifdef CONFIG_RT_MUTEXES
641static DEFINE_RT_MUTEX(torture_rtmutex);
642static struct rt_mutex torture_nested_rtmutexes[MAX_NESTED_LOCKS];
643static struct lock_class_key nested_rtmutex_keys[MAX_NESTED_LOCKS];
644
645static void torture_rtmutex_init(void)
646{
647 int i;
648
649 for (i = 0; i < MAX_NESTED_LOCKS; i++)
650 __rt_mutex_init(&torture_nested_rtmutexes[i], __func__,
651 &nested_rtmutex_keys[i]);
652}
653
654static int torture_rtmutex_nested_lock(int tid __maybe_unused,
655 u32 lockset)
656{
657 int i;
658
659 for (i = 0; i < nested_locks; i++)
660 if (lockset & (1 << i))
661 rt_mutex_lock(&torture_nested_rtmutexes[i]);
662 return 0;
663}
664
665static int torture_rtmutex_lock(int tid __maybe_unused)
666__acquires(torture_rtmutex)
667{
668 rt_mutex_lock(&torture_rtmutex);
669 return 0;
670}
671
672static void torture_rtmutex_delay(struct torture_random_state *trsp)
673{
674 const unsigned long shortdelay_us = 2;
675
676 /*
677 * We want a short delay mostly to emulate likely code, and
678 * we want a long delay occasionally to force massive contention.
679 */
680 if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold)))
681 mdelay(long_hold);
682 if (!(torture_random(trsp) %
683 (cxt.nrealwriters_stress * 200 * shortdelay_us)))
684 udelay(shortdelay_us);
685 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
686 torture_preempt_schedule(); /* Allow test to be preempted. */
687}
688
689static void torture_rtmutex_unlock(int tid __maybe_unused)
690__releases(torture_rtmutex)
691{
692 rt_mutex_unlock(&torture_rtmutex);
693}
694
695static void torture_rt_boost_rtmutex(struct torture_random_state *trsp)
696{
697 if (!rt_boost)
698 return;
699
700 __torture_rt_boost(trsp);
701}
702
703static void torture_rtmutex_nested_unlock(int tid __maybe_unused,
704 u32 lockset)
705{
706 int i;
707
708 for (i = nested_locks - 1; i >= 0; i--)
709 if (lockset & (1 << i))
710 rt_mutex_unlock(&torture_nested_rtmutexes[i]);
711}
712
713static struct lock_torture_ops rtmutex_lock_ops = {
714 .init = torture_rtmutex_init,
715 .nested_lock = torture_rtmutex_nested_lock,
716 .writelock = torture_rtmutex_lock,
717 .write_delay = torture_rtmutex_delay,
718 .task_boost = torture_rt_boost_rtmutex,
719 .writeunlock = torture_rtmutex_unlock,
720 .nested_unlock = torture_rtmutex_nested_unlock,
721 .readlock = NULL,
722 .read_delay = NULL,
723 .readunlock = NULL,
724 .name = "rtmutex_lock"
725};
726#endif
727
728static DECLARE_RWSEM(torture_rwsem);
729static int torture_rwsem_down_write(int tid __maybe_unused)
730__acquires(torture_rwsem)
731{
732 down_write(&torture_rwsem);
733 return 0;
734}
735
736static void torture_rwsem_write_delay(struct torture_random_state *trsp)
737{
738 /* We want a long delay occasionally to force massive contention. */
739 if (long_hold && !(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * long_hold)))
740 mdelay(long_hold * 10);
741 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
742 torture_preempt_schedule(); /* Allow test to be preempted. */
743}
744
745static void torture_rwsem_up_write(int tid __maybe_unused)
746__releases(torture_rwsem)
747{
748 up_write(&torture_rwsem);
749}
750
751static int torture_rwsem_down_read(int tid __maybe_unused)
752__acquires(torture_rwsem)
753{
754 down_read(&torture_rwsem);
755 return 0;
756}
757
758static void torture_rwsem_read_delay(struct torture_random_state *trsp)
759{
760 /* We want a long delay occasionally to force massive contention. */
761 if (long_hold && !(torture_random(trsp) % (cxt.nrealreaders_stress * 2000 * long_hold)))
762 mdelay(long_hold * 2);
763 else
764 mdelay(long_hold / 2);
765 if (!(torture_random(trsp) % (cxt.nrealreaders_stress * 20000)))
766 torture_preempt_schedule(); /* Allow test to be preempted. */
767}
768
769static void torture_rwsem_up_read(int tid __maybe_unused)
770__releases(torture_rwsem)
771{
772 up_read(&torture_rwsem);
773}
774
775static struct lock_torture_ops rwsem_lock_ops = {
776 .writelock = torture_rwsem_down_write,
777 .write_delay = torture_rwsem_write_delay,
778 .task_boost = torture_rt_boost,
779 .writeunlock = torture_rwsem_up_write,
780 .readlock = torture_rwsem_down_read,
781 .read_delay = torture_rwsem_read_delay,
782 .readunlock = torture_rwsem_up_read,
783 .name = "rwsem_lock"
784};
785
786#include <linux/percpu-rwsem.h>
787static struct percpu_rw_semaphore pcpu_rwsem;
788
789static void torture_percpu_rwsem_init(void)
790{
791 BUG_ON(percpu_init_rwsem(&pcpu_rwsem));
792}
793
794static void torture_percpu_rwsem_exit(void)
795{
796 percpu_free_rwsem(&pcpu_rwsem);
797}
798
799static int torture_percpu_rwsem_down_write(int tid __maybe_unused)
800__acquires(pcpu_rwsem)
801{
802 percpu_down_write(&pcpu_rwsem);
803 return 0;
804}
805
806static void torture_percpu_rwsem_up_write(int tid __maybe_unused)
807__releases(pcpu_rwsem)
808{
809 percpu_up_write(&pcpu_rwsem);
810}
811
812static int torture_percpu_rwsem_down_read(int tid __maybe_unused)
813__acquires(pcpu_rwsem)
814{
815 percpu_down_read(&pcpu_rwsem);
816 return 0;
817}
818
819static void torture_percpu_rwsem_up_read(int tid __maybe_unused)
820__releases(pcpu_rwsem)
821{
822 percpu_up_read(&pcpu_rwsem);
823}
824
825static struct lock_torture_ops percpu_rwsem_lock_ops = {
826 .init = torture_percpu_rwsem_init,
827 .exit = torture_percpu_rwsem_exit,
828 .writelock = torture_percpu_rwsem_down_write,
829 .write_delay = torture_rwsem_write_delay,
830 .task_boost = torture_rt_boost,
831 .writeunlock = torture_percpu_rwsem_up_write,
832 .readlock = torture_percpu_rwsem_down_read,
833 .read_delay = torture_rwsem_read_delay,
834 .readunlock = torture_percpu_rwsem_up_read,
835 .name = "percpu_rwsem_lock"
836};
837
838/*
839 * Lock torture writer kthread. Repeatedly acquires and releases
840 * the lock, checking for duplicate acquisitions.
841 */
842static int lock_torture_writer(void *arg)
843{
844 unsigned long j;
845 unsigned long j1;
846 u32 lockset_mask;
847 struct lock_stress_stats *lwsp = arg;
848 DEFINE_TORTURE_RANDOM(rand);
849 bool skip_main_lock;
850 int tid = lwsp - cxt.lwsa;
851
852 VERBOSE_TOROUT_STRING("lock_torture_writer task started");
853 if (!rt_task(current))
854 set_user_nice(current, MAX_NICE);
855
856 do {
857 if ((torture_random(&rand) & 0xfffff) == 0)
858 schedule_timeout_uninterruptible(1);
859
860 lockset_mask = torture_random(&rand);
861 /*
862 * When using nested_locks, we want to occasionally
863 * skip the main lock so we can avoid always serializing
864 * the lock chains on that central lock. By skipping the
865 * main lock occasionally, we can create different
866 * contention patterns (allowing for multiple disjoint
867 * blocked trees)
868 */
869 skip_main_lock = (nested_locks &&
870 !(torture_random(&rand) % 100));
871
872 cxt.cur_ops->task_boost(&rand);
873 if (cxt.cur_ops->nested_lock)
874 cxt.cur_ops->nested_lock(tid, lockset_mask);
875
876 if (!skip_main_lock) {
877 if (acq_writer_lim > 0)
878 j = jiffies;
879 cxt.cur_ops->writelock(tid);
880 if (WARN_ON_ONCE(lock_is_write_held))
881 lwsp->n_lock_fail++;
882 lock_is_write_held = true;
883 if (WARN_ON_ONCE(atomic_read(&lock_is_read_held)))
884 lwsp->n_lock_fail++; /* rare, but... */
885 if (acq_writer_lim > 0) {
886 j1 = jiffies;
887 WARN_ONCE(time_after(j1, j + acq_writer_lim),
888 "%s: Lock acquisition took %lu jiffies.\n",
889 __func__, j1 - j);
890 }
891 lwsp->n_lock_acquired++;
892
893 cxt.cur_ops->write_delay(&rand);
894
895 lock_is_write_held = false;
896 WRITE_ONCE(last_lock_release, jiffies);
897 cxt.cur_ops->writeunlock(tid);
898 }
899 if (cxt.cur_ops->nested_unlock)
900 cxt.cur_ops->nested_unlock(tid, lockset_mask);
901
902 stutter_wait("lock_torture_writer");
903 } while (!torture_must_stop());
904
905 cxt.cur_ops->task_boost(NULL); /* reset prio */
906 torture_kthread_stopping("lock_torture_writer");
907 return 0;
908}
909
910/*
911 * Lock torture reader kthread. Repeatedly acquires and releases
912 * the reader lock.
913 */
914static int lock_torture_reader(void *arg)
915{
916 struct lock_stress_stats *lrsp = arg;
917 int tid = lrsp - cxt.lrsa;
918 DEFINE_TORTURE_RANDOM(rand);
919
920 VERBOSE_TOROUT_STRING("lock_torture_reader task started");
921 set_user_nice(current, MAX_NICE);
922
923 do {
924 if ((torture_random(&rand) & 0xfffff) == 0)
925 schedule_timeout_uninterruptible(1);
926
927 cxt.cur_ops->readlock(tid);
928 atomic_inc(&lock_is_read_held);
929 if (WARN_ON_ONCE(lock_is_write_held))
930 lrsp->n_lock_fail++; /* rare, but... */
931
932 lrsp->n_lock_acquired++;
933 cxt.cur_ops->read_delay(&rand);
934 atomic_dec(&lock_is_read_held);
935 cxt.cur_ops->readunlock(tid);
936
937 stutter_wait("lock_torture_reader");
938 } while (!torture_must_stop());
939 torture_kthread_stopping("lock_torture_reader");
940 return 0;
941}
942
943/*
944 * Create an lock-torture-statistics message in the specified buffer.
945 */
946static void __torture_print_stats(char *page,
947 struct lock_stress_stats *statp, bool write)
948{
949 long cur;
950 bool fail = false;
951 int i, n_stress;
952 long max = 0, min = statp ? data_race(statp[0].n_lock_acquired) : 0;
953 long long sum = 0;
954
955 n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress;
956 for (i = 0; i < n_stress; i++) {
957 if (data_race(statp[i].n_lock_fail))
958 fail = true;
959 cur = data_race(statp[i].n_lock_acquired);
960 sum += cur;
961 if (max < cur)
962 max = cur;
963 if (min > cur)
964 min = cur;
965 }
966 page += sprintf(page,
967 "%s: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n",
968 write ? "Writes" : "Reads ",
969 sum, max, min,
970 !onoff_interval && max / 2 > min ? "???" : "",
971 fail, fail ? "!!!" : "");
972 if (fail)
973 atomic_inc(&cxt.n_lock_torture_errors);
974}
975
976/*
977 * Print torture statistics. Caller must ensure that there is only one
978 * call to this function at a given time!!! This is normally accomplished
979 * by relying on the module system to only have one copy of the module
980 * loaded, and then by giving the lock_torture_stats kthread full control
981 * (or the init/cleanup functions when lock_torture_stats thread is not
982 * running).
983 */
984static void lock_torture_stats_print(void)
985{
986 int size = cxt.nrealwriters_stress * 200 + 8192;
987 char *buf;
988
989 if (cxt.cur_ops->readlock)
990 size += cxt.nrealreaders_stress * 200 + 8192;
991
992 buf = kmalloc(size, GFP_KERNEL);
993 if (!buf) {
994 pr_err("lock_torture_stats_print: Out of memory, need: %d",
995 size);
996 return;
997 }
998
999 __torture_print_stats(buf, cxt.lwsa, true);
1000 pr_alert("%s", buf);
1001 kfree(buf);
1002
1003 if (cxt.cur_ops->readlock) {
1004 buf = kmalloc(size, GFP_KERNEL);
1005 if (!buf) {
1006 pr_err("lock_torture_stats_print: Out of memory, need: %d",
1007 size);
1008 return;
1009 }
1010
1011 __torture_print_stats(buf, cxt.lrsa, false);
1012 pr_alert("%s", buf);
1013 kfree(buf);
1014 }
1015}
1016
1017/*
1018 * Periodically prints torture statistics, if periodic statistics printing
1019 * was specified via the stat_interval module parameter.
1020 *
1021 * No need to worry about fullstop here, since this one doesn't reference
1022 * volatile state or register callbacks.
1023 */
1024static int lock_torture_stats(void *arg)
1025{
1026 VERBOSE_TOROUT_STRING("lock_torture_stats task started");
1027 do {
1028 schedule_timeout_interruptible(stat_interval * HZ);
1029 lock_torture_stats_print();
1030 torture_shutdown_absorb("lock_torture_stats");
1031 } while (!torture_must_stop());
1032 torture_kthread_stopping("lock_torture_stats");
1033 return 0;
1034}
1035
1036
1037static inline void
1038lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
1039 const char *tag)
1040{
1041 static cpumask_t cpumask_all;
1042 cpumask_t *rcmp = cpumask_nonempty(bind_readers) ? bind_readers : &cpumask_all;
1043 cpumask_t *wcmp = cpumask_nonempty(bind_writers) ? bind_writers : &cpumask_all;
1044
1045 cpumask_setall(&cpumask_all);
1046 pr_alert("%s" TORTURE_FLAG
1047 "--- %s%s: acq_writer_lim=%d bind_readers=%*pbl bind_writers=%*pbl call_rcu_chains=%d long_hold=%d nested_locks=%d nreaders_stress=%d nwriters_stress=%d onoff_holdoff=%d onoff_interval=%d rt_boost=%d rt_boost_factor=%d shuffle_interval=%d shutdown_secs=%d stat_interval=%d stutter=%d verbose=%d writer_fifo=%d\n",
1048 torture_type, tag, cxt.debug_lock ? " [debug]": "",
1049 acq_writer_lim, cpumask_pr_args(rcmp), cpumask_pr_args(wcmp),
1050 call_rcu_chains, long_hold, nested_locks, cxt.nrealreaders_stress,
1051 cxt.nrealwriters_stress, onoff_holdoff, onoff_interval, rt_boost,
1052 rt_boost_factor, shuffle_interval, shutdown_secs, stat_interval, stutter,
1053 verbose, writer_fifo);
1054}
1055
1056// If requested, maintain call_rcu() chains to keep a grace period always
1057// in flight. These increase the probability of getting an RCU CPU stall
1058// warning and associated diagnostics when a locking primitive stalls.
1059
1060static void call_rcu_chain_cb(struct rcu_head *rhp)
1061{
1062 struct call_rcu_chain *crcp = container_of(rhp, struct call_rcu_chain, crc_rh);
1063
1064 if (!smp_load_acquire(&crcp->crc_stop)) {
1065 (void)start_poll_synchronize_rcu(); // Start one grace period...
1066 call_rcu(&crcp->crc_rh, call_rcu_chain_cb); // ... and later start another.
1067 }
1068}
1069
1070// Start the requested number of call_rcu() chains.
1071static int call_rcu_chain_init(void)
1072{
1073 int i;
1074
1075 if (call_rcu_chains <= 0)
1076 return 0;
1077 call_rcu_chain_list = kcalloc(call_rcu_chains, sizeof(*call_rcu_chain_list), GFP_KERNEL);
1078 if (!call_rcu_chain_list)
1079 return -ENOMEM;
1080 for (i = 0; i < call_rcu_chains; i++) {
1081 call_rcu_chain_list[i].crc_stop = false;
1082 call_rcu(&call_rcu_chain_list[i].crc_rh, call_rcu_chain_cb);
1083 }
1084 return 0;
1085}
1086
1087// Stop all of the call_rcu() chains.
1088static void call_rcu_chain_cleanup(void)
1089{
1090 int i;
1091
1092 if (!call_rcu_chain_list)
1093 return;
1094 for (i = 0; i < call_rcu_chains; i++)
1095 smp_store_release(&call_rcu_chain_list[i].crc_stop, true);
1096 rcu_barrier();
1097 kfree(call_rcu_chain_list);
1098 call_rcu_chain_list = NULL;
1099}
1100
1101static void lock_torture_cleanup(void)
1102{
1103 int i;
1104
1105 if (torture_cleanup_begin())
1106 return;
1107
1108 /*
1109 * Indicates early cleanup, meaning that the test has not run,
1110 * such as when passing bogus args when loading the module.
1111 * However cxt->cur_ops.init() may have been invoked, so beside
1112 * perform the underlying torture-specific cleanups, cur_ops.exit()
1113 * will be invoked if needed.
1114 */
1115 if (!cxt.lwsa && !cxt.lrsa)
1116 goto end;
1117
1118 if (writer_tasks) {
1119 for (i = 0; i < cxt.nrealwriters_stress; i++)
1120 torture_stop_kthread(lock_torture_writer, writer_tasks[i]);
1121 kfree(writer_tasks);
1122 writer_tasks = NULL;
1123 }
1124
1125 if (reader_tasks) {
1126 for (i = 0; i < cxt.nrealreaders_stress; i++)
1127 torture_stop_kthread(lock_torture_reader,
1128 reader_tasks[i]);
1129 kfree(reader_tasks);
1130 reader_tasks = NULL;
1131 }
1132
1133 torture_stop_kthread(lock_torture_stats, stats_task);
1134 lock_torture_stats_print(); /* -After- the stats thread is stopped! */
1135
1136 if (atomic_read(&cxt.n_lock_torture_errors))
1137 lock_torture_print_module_parms(cxt.cur_ops,
1138 "End of test: FAILURE");
1139 else if (torture_onoff_failures())
1140 lock_torture_print_module_parms(cxt.cur_ops,
1141 "End of test: LOCK_HOTPLUG");
1142 else
1143 lock_torture_print_module_parms(cxt.cur_ops,
1144 "End of test: SUCCESS");
1145
1146 kfree(cxt.lwsa);
1147 cxt.lwsa = NULL;
1148 kfree(cxt.lrsa);
1149 cxt.lrsa = NULL;
1150
1151 call_rcu_chain_cleanup();
1152
1153end:
1154 if (cxt.init_called) {
1155 if (cxt.cur_ops->exit)
1156 cxt.cur_ops->exit();
1157 cxt.init_called = false;
1158 }
1159 torture_cleanup_end();
1160}
1161
1162static int __init lock_torture_init(void)
1163{
1164 int i, j;
1165 int firsterr = 0;
1166 static struct lock_torture_ops *torture_ops[] = {
1167 &lock_busted_ops,
1168 &spin_lock_ops, &spin_lock_irq_ops,
1169 &raw_spin_lock_ops, &raw_spin_lock_irq_ops,
1170 &rw_lock_ops, &rw_lock_irq_ops,
1171 &mutex_lock_ops,
1172 &ww_mutex_lock_ops,
1173#ifdef CONFIG_RT_MUTEXES
1174 &rtmutex_lock_ops,
1175#endif
1176 &rwsem_lock_ops,
1177 &percpu_rwsem_lock_ops,
1178 };
1179
1180 if (!torture_init_begin(torture_type, verbose))
1181 return -EBUSY;
1182
1183 /* Process args and tell the world that the torturer is on the job. */
1184 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1185 cxt.cur_ops = torture_ops[i];
1186 if (strcmp(torture_type, cxt.cur_ops->name) == 0)
1187 break;
1188 }
1189 if (i == ARRAY_SIZE(torture_ops)) {
1190 pr_alert("lock-torture: invalid torture type: \"%s\"\n",
1191 torture_type);
1192 pr_alert("lock-torture types:");
1193 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1194 pr_alert(" %s", torture_ops[i]->name);
1195 pr_alert("\n");
1196 firsterr = -EINVAL;
1197 goto unwind;
1198 }
1199
1200 if (nwriters_stress == 0 &&
1201 (!cxt.cur_ops->readlock || nreaders_stress == 0)) {
1202 pr_alert("lock-torture: must run at least one locking thread\n");
1203 firsterr = -EINVAL;
1204 goto unwind;
1205 }
1206
1207 if (nwriters_stress >= 0)
1208 cxt.nrealwriters_stress = nwriters_stress;
1209 else
1210 cxt.nrealwriters_stress = 2 * num_online_cpus();
1211
1212 if (cxt.cur_ops->init) {
1213 cxt.cur_ops->init();
1214 cxt.init_called = true;
1215 }
1216
1217#ifdef CONFIG_DEBUG_MUTEXES
1218 if (str_has_prefix(torture_type, "mutex"))
1219 cxt.debug_lock = true;
1220#endif
1221#ifdef CONFIG_DEBUG_RT_MUTEXES
1222 if (str_has_prefix(torture_type, "rtmutex"))
1223 cxt.debug_lock = true;
1224#endif
1225#ifdef CONFIG_DEBUG_SPINLOCK
1226 if ((str_has_prefix(torture_type, "spin")) ||
1227 (str_has_prefix(torture_type, "rw_lock")))
1228 cxt.debug_lock = true;
1229#endif
1230
1231 /* Initialize the statistics so that each run gets its own numbers. */
1232 if (nwriters_stress) {
1233 lock_is_write_held = false;
1234 cxt.lwsa = kmalloc_array(cxt.nrealwriters_stress,
1235 sizeof(*cxt.lwsa),
1236 GFP_KERNEL);
1237 if (cxt.lwsa == NULL) {
1238 VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory");
1239 firsterr = -ENOMEM;
1240 goto unwind;
1241 }
1242
1243 for (i = 0; i < cxt.nrealwriters_stress; i++) {
1244 cxt.lwsa[i].n_lock_fail = 0;
1245 cxt.lwsa[i].n_lock_acquired = 0;
1246 }
1247 }
1248
1249 if (cxt.cur_ops->readlock) {
1250 if (nreaders_stress >= 0)
1251 cxt.nrealreaders_stress = nreaders_stress;
1252 else {
1253 /*
1254 * By default distribute evenly the number of
1255 * readers and writers. We still run the same number
1256 * of threads as the writer-only locks default.
1257 */
1258 if (nwriters_stress < 0) /* user doesn't care */
1259 cxt.nrealwriters_stress = num_online_cpus();
1260 cxt.nrealreaders_stress = cxt.nrealwriters_stress;
1261 }
1262
1263 if (nreaders_stress) {
1264 cxt.lrsa = kmalloc_array(cxt.nrealreaders_stress,
1265 sizeof(*cxt.lrsa),
1266 GFP_KERNEL);
1267 if (cxt.lrsa == NULL) {
1268 VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory");
1269 firsterr = -ENOMEM;
1270 kfree(cxt.lwsa);
1271 cxt.lwsa = NULL;
1272 goto unwind;
1273 }
1274
1275 for (i = 0; i < cxt.nrealreaders_stress; i++) {
1276 cxt.lrsa[i].n_lock_fail = 0;
1277 cxt.lrsa[i].n_lock_acquired = 0;
1278 }
1279 }
1280 }
1281
1282 firsterr = call_rcu_chain_init();
1283 if (torture_init_error(firsterr))
1284 goto unwind;
1285
1286 lock_torture_print_module_parms(cxt.cur_ops, "Start of test");
1287
1288 /* Prepare torture context. */
1289 if (onoff_interval > 0) {
1290 firsterr = torture_onoff_init(onoff_holdoff * HZ,
1291 onoff_interval * HZ, NULL);
1292 if (torture_init_error(firsterr))
1293 goto unwind;
1294 }
1295 if (shuffle_interval > 0) {
1296 firsterr = torture_shuffle_init(shuffle_interval);
1297 if (torture_init_error(firsterr))
1298 goto unwind;
1299 }
1300 if (shutdown_secs > 0) {
1301 firsterr = torture_shutdown_init(shutdown_secs,
1302 lock_torture_cleanup);
1303 if (torture_init_error(firsterr))
1304 goto unwind;
1305 }
1306 if (stutter > 0) {
1307 firsterr = torture_stutter_init(stutter, stutter);
1308 if (torture_init_error(firsterr))
1309 goto unwind;
1310 }
1311
1312 if (nwriters_stress) {
1313 writer_tasks = kcalloc(cxt.nrealwriters_stress,
1314 sizeof(writer_tasks[0]),
1315 GFP_KERNEL);
1316 if (writer_tasks == NULL) {
1317 TOROUT_ERRSTRING("writer_tasks: Out of memory");
1318 firsterr = -ENOMEM;
1319 goto unwind;
1320 }
1321 }
1322
1323 /* cap nested_locks to MAX_NESTED_LOCKS */
1324 if (nested_locks > MAX_NESTED_LOCKS)
1325 nested_locks = MAX_NESTED_LOCKS;
1326
1327 if (cxt.cur_ops->readlock) {
1328 reader_tasks = kcalloc(cxt.nrealreaders_stress,
1329 sizeof(reader_tasks[0]),
1330 GFP_KERNEL);
1331 if (reader_tasks == NULL) {
1332 TOROUT_ERRSTRING("reader_tasks: Out of memory");
1333 kfree(writer_tasks);
1334 writer_tasks = NULL;
1335 firsterr = -ENOMEM;
1336 goto unwind;
1337 }
1338 }
1339
1340 /*
1341 * Create the kthreads and start torturing (oh, those poor little locks).
1342 *
1343 * TODO: Note that we interleave writers with readers, giving writers a
1344 * slight advantage, by creating its kthread first. This can be modified
1345 * for very specific needs, or even let the user choose the policy, if
1346 * ever wanted.
1347 */
1348 for (i = 0, j = 0; i < cxt.nrealwriters_stress ||
1349 j < cxt.nrealreaders_stress; i++, j++) {
1350 if (i >= cxt.nrealwriters_stress)
1351 goto create_reader;
1352
1353 /* Create writer. */
1354 firsterr = torture_create_kthread_cb(lock_torture_writer, &cxt.lwsa[i],
1355 writer_tasks[i],
1356 writer_fifo ? sched_set_fifo : NULL);
1357 if (torture_init_error(firsterr))
1358 goto unwind;
1359 if (cpumask_nonempty(bind_writers))
1360 torture_sched_setaffinity(writer_tasks[i]->pid, bind_writers);
1361
1362 create_reader:
1363 if (cxt.cur_ops->readlock == NULL || (j >= cxt.nrealreaders_stress))
1364 continue;
1365 /* Create reader. */
1366 firsterr = torture_create_kthread(lock_torture_reader, &cxt.lrsa[j],
1367 reader_tasks[j]);
1368 if (torture_init_error(firsterr))
1369 goto unwind;
1370 if (cpumask_nonempty(bind_readers))
1371 torture_sched_setaffinity(reader_tasks[j]->pid, bind_readers);
1372 }
1373 if (stat_interval > 0) {
1374 firsterr = torture_create_kthread(lock_torture_stats, NULL,
1375 stats_task);
1376 if (torture_init_error(firsterr))
1377 goto unwind;
1378 }
1379 torture_init_end();
1380 return 0;
1381
1382unwind:
1383 torture_init_end();
1384 lock_torture_cleanup();
1385 if (shutdown_secs) {
1386 WARN_ON(!IS_MODULE(CONFIG_LOCK_TORTURE_TEST));
1387 kernel_power_off();
1388 }
1389 return firsterr;
1390}
1391
1392module_init(lock_torture_init);
1393module_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/torture.h>
31#include <linux/reboot.h>
32
33MODULE_LICENSE("GPL");
34MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>");
35
36torture_param(int, nwriters_stress, -1,
37 "Number of write-locking stress-test threads");
38torture_param(int, nreaders_stress, -1,
39 "Number of read-locking stress-test threads");
40torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
41torture_param(int, onoff_interval, 0,
42 "Time between CPU hotplugs (s), 0=disable");
43torture_param(int, shuffle_interval, 3,
44 "Number of jiffies between shuffles, 0=disable");
45torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable.");
46torture_param(int, stat_interval, 60,
47 "Number of seconds between stats printk()s");
48torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
49torture_param(int, verbose, 1,
50 "Enable verbose debugging printk()s");
51
52static char *torture_type = "spin_lock";
53module_param(torture_type, charp, 0444);
54MODULE_PARM_DESC(torture_type,
55 "Type of lock to torture (spin_lock, spin_lock_irq, mutex_lock, ...)");
56
57static struct task_struct *stats_task;
58static struct task_struct **writer_tasks;
59static struct task_struct **reader_tasks;
60
61static bool lock_is_write_held;
62static bool lock_is_read_held;
63static unsigned long last_lock_release;
64
65struct lock_stress_stats {
66 long n_lock_fail;
67 long n_lock_acquired;
68};
69
70/* Forward reference. */
71static void lock_torture_cleanup(void);
72
73/*
74 * Operations vector for selecting different types of tests.
75 */
76struct lock_torture_ops {
77 void (*init)(void);
78 void (*exit)(void);
79 int (*writelock)(int tid);
80 void (*write_delay)(struct torture_random_state *trsp);
81 void (*task_boost)(struct torture_random_state *trsp);
82 void (*writeunlock)(int tid);
83 int (*readlock)(int tid);
84 void (*read_delay)(struct torture_random_state *trsp);
85 void (*readunlock)(int tid);
86
87 unsigned long flags; /* for irq spinlocks */
88 const char *name;
89};
90
91struct lock_torture_cxt {
92 int nrealwriters_stress;
93 int nrealreaders_stress;
94 bool debug_lock;
95 bool init_called;
96 atomic_t n_lock_torture_errors;
97 struct lock_torture_ops *cur_ops;
98 struct lock_stress_stats *lwsa; /* writer statistics */
99 struct lock_stress_stats *lrsa; /* reader statistics */
100};
101static struct lock_torture_cxt cxt = { 0, 0, false, false,
102 ATOMIC_INIT(0),
103 NULL, NULL};
104/*
105 * Definitions for lock torture testing.
106 */
107
108static int torture_lock_busted_write_lock(int tid __maybe_unused)
109{
110 return 0; /* BUGGY, do not use in real life!!! */
111}
112
113static void torture_lock_busted_write_delay(struct torture_random_state *trsp)
114{
115 const unsigned long longdelay_ms = 100;
116
117 /* We want a long delay occasionally to force massive contention. */
118 if (!(torture_random(trsp) %
119 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
120 mdelay(longdelay_ms);
121 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
122 torture_preempt_schedule(); /* Allow test to be preempted. */
123}
124
125static void torture_lock_busted_write_unlock(int tid __maybe_unused)
126{
127 /* BUGGY, do not use in real life!!! */
128}
129
130static void torture_boost_dummy(struct torture_random_state *trsp)
131{
132 /* Only rtmutexes care about priority */
133}
134
135static struct lock_torture_ops lock_busted_ops = {
136 .writelock = torture_lock_busted_write_lock,
137 .write_delay = torture_lock_busted_write_delay,
138 .task_boost = torture_boost_dummy,
139 .writeunlock = torture_lock_busted_write_unlock,
140 .readlock = NULL,
141 .read_delay = NULL,
142 .readunlock = NULL,
143 .name = "lock_busted"
144};
145
146static DEFINE_SPINLOCK(torture_spinlock);
147
148static int torture_spin_lock_write_lock(int tid __maybe_unused)
149__acquires(torture_spinlock)
150{
151 spin_lock(&torture_spinlock);
152 return 0;
153}
154
155static void torture_spin_lock_write_delay(struct torture_random_state *trsp)
156{
157 const unsigned long shortdelay_us = 2;
158 const unsigned long longdelay_ms = 100;
159
160 /* We want a short delay mostly to emulate likely code, and
161 * we want a long delay occasionally to force massive contention.
162 */
163 if (!(torture_random(trsp) %
164 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
165 mdelay(longdelay_ms);
166 if (!(torture_random(trsp) %
167 (cxt.nrealwriters_stress * 2 * shortdelay_us)))
168 udelay(shortdelay_us);
169 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
170 torture_preempt_schedule(); /* Allow test to be preempted. */
171}
172
173static void torture_spin_lock_write_unlock(int tid __maybe_unused)
174__releases(torture_spinlock)
175{
176 spin_unlock(&torture_spinlock);
177}
178
179static struct lock_torture_ops spin_lock_ops = {
180 .writelock = torture_spin_lock_write_lock,
181 .write_delay = torture_spin_lock_write_delay,
182 .task_boost = torture_boost_dummy,
183 .writeunlock = torture_spin_lock_write_unlock,
184 .readlock = NULL,
185 .read_delay = NULL,
186 .readunlock = NULL,
187 .name = "spin_lock"
188};
189
190static int torture_spin_lock_write_lock_irq(int tid __maybe_unused)
191__acquires(torture_spinlock)
192{
193 unsigned long flags;
194
195 spin_lock_irqsave(&torture_spinlock, flags);
196 cxt.cur_ops->flags = flags;
197 return 0;
198}
199
200static void torture_lock_spin_write_unlock_irq(int tid __maybe_unused)
201__releases(torture_spinlock)
202{
203 spin_unlock_irqrestore(&torture_spinlock, cxt.cur_ops->flags);
204}
205
206static struct lock_torture_ops spin_lock_irq_ops = {
207 .writelock = torture_spin_lock_write_lock_irq,
208 .write_delay = torture_spin_lock_write_delay,
209 .task_boost = torture_boost_dummy,
210 .writeunlock = torture_lock_spin_write_unlock_irq,
211 .readlock = NULL,
212 .read_delay = NULL,
213 .readunlock = NULL,
214 .name = "spin_lock_irq"
215};
216
217static DEFINE_RWLOCK(torture_rwlock);
218
219static int torture_rwlock_write_lock(int tid __maybe_unused)
220__acquires(torture_rwlock)
221{
222 write_lock(&torture_rwlock);
223 return 0;
224}
225
226static void torture_rwlock_write_delay(struct torture_random_state *trsp)
227{
228 const unsigned long shortdelay_us = 2;
229 const unsigned long longdelay_ms = 100;
230
231 /* We want a short delay mostly to emulate likely code, and
232 * we want a long delay occasionally to force massive contention.
233 */
234 if (!(torture_random(trsp) %
235 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
236 mdelay(longdelay_ms);
237 else
238 udelay(shortdelay_us);
239}
240
241static void torture_rwlock_write_unlock(int tid __maybe_unused)
242__releases(torture_rwlock)
243{
244 write_unlock(&torture_rwlock);
245}
246
247static int torture_rwlock_read_lock(int tid __maybe_unused)
248__acquires(torture_rwlock)
249{
250 read_lock(&torture_rwlock);
251 return 0;
252}
253
254static void torture_rwlock_read_delay(struct torture_random_state *trsp)
255{
256 const unsigned long shortdelay_us = 10;
257 const unsigned long longdelay_ms = 100;
258
259 /* We want a short delay mostly to emulate likely code, and
260 * we want a long delay occasionally to force massive contention.
261 */
262 if (!(torture_random(trsp) %
263 (cxt.nrealreaders_stress * 2000 * longdelay_ms)))
264 mdelay(longdelay_ms);
265 else
266 udelay(shortdelay_us);
267}
268
269static void torture_rwlock_read_unlock(int tid __maybe_unused)
270__releases(torture_rwlock)
271{
272 read_unlock(&torture_rwlock);
273}
274
275static struct lock_torture_ops rw_lock_ops = {
276 .writelock = torture_rwlock_write_lock,
277 .write_delay = torture_rwlock_write_delay,
278 .task_boost = torture_boost_dummy,
279 .writeunlock = torture_rwlock_write_unlock,
280 .readlock = torture_rwlock_read_lock,
281 .read_delay = torture_rwlock_read_delay,
282 .readunlock = torture_rwlock_read_unlock,
283 .name = "rw_lock"
284};
285
286static int torture_rwlock_write_lock_irq(int tid __maybe_unused)
287__acquires(torture_rwlock)
288{
289 unsigned long flags;
290
291 write_lock_irqsave(&torture_rwlock, flags);
292 cxt.cur_ops->flags = flags;
293 return 0;
294}
295
296static void torture_rwlock_write_unlock_irq(int tid __maybe_unused)
297__releases(torture_rwlock)
298{
299 write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
300}
301
302static int torture_rwlock_read_lock_irq(int tid __maybe_unused)
303__acquires(torture_rwlock)
304{
305 unsigned long flags;
306
307 read_lock_irqsave(&torture_rwlock, flags);
308 cxt.cur_ops->flags = flags;
309 return 0;
310}
311
312static void torture_rwlock_read_unlock_irq(int tid __maybe_unused)
313__releases(torture_rwlock)
314{
315 read_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
316}
317
318static struct lock_torture_ops rw_lock_irq_ops = {
319 .writelock = torture_rwlock_write_lock_irq,
320 .write_delay = torture_rwlock_write_delay,
321 .task_boost = torture_boost_dummy,
322 .writeunlock = torture_rwlock_write_unlock_irq,
323 .readlock = torture_rwlock_read_lock_irq,
324 .read_delay = torture_rwlock_read_delay,
325 .readunlock = torture_rwlock_read_unlock_irq,
326 .name = "rw_lock_irq"
327};
328
329static DEFINE_MUTEX(torture_mutex);
330
331static int torture_mutex_lock(int tid __maybe_unused)
332__acquires(torture_mutex)
333{
334 mutex_lock(&torture_mutex);
335 return 0;
336}
337
338static void torture_mutex_delay(struct torture_random_state *trsp)
339{
340 const unsigned long longdelay_ms = 100;
341
342 /* We want a long delay occasionally to force massive contention. */
343 if (!(torture_random(trsp) %
344 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
345 mdelay(longdelay_ms * 5);
346 else
347 mdelay(longdelay_ms / 5);
348 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
349 torture_preempt_schedule(); /* Allow test to be preempted. */
350}
351
352static void torture_mutex_unlock(int tid __maybe_unused)
353__releases(torture_mutex)
354{
355 mutex_unlock(&torture_mutex);
356}
357
358static struct lock_torture_ops mutex_lock_ops = {
359 .writelock = torture_mutex_lock,
360 .write_delay = torture_mutex_delay,
361 .task_boost = torture_boost_dummy,
362 .writeunlock = torture_mutex_unlock,
363 .readlock = NULL,
364 .read_delay = NULL,
365 .readunlock = NULL,
366 .name = "mutex_lock"
367};
368
369#include <linux/ww_mutex.h>
370/*
371 * The torture ww_mutexes should belong to the same lock class as
372 * torture_ww_class to avoid lockdep problem. The ww_mutex_init()
373 * function is called for initialization to ensure that.
374 */
375static DEFINE_WD_CLASS(torture_ww_class);
376static struct ww_mutex torture_ww_mutex_0, torture_ww_mutex_1, torture_ww_mutex_2;
377static struct ww_acquire_ctx *ww_acquire_ctxs;
378
379static void torture_ww_mutex_init(void)
380{
381 ww_mutex_init(&torture_ww_mutex_0, &torture_ww_class);
382 ww_mutex_init(&torture_ww_mutex_1, &torture_ww_class);
383 ww_mutex_init(&torture_ww_mutex_2, &torture_ww_class);
384
385 ww_acquire_ctxs = kmalloc_array(cxt.nrealwriters_stress,
386 sizeof(*ww_acquire_ctxs),
387 GFP_KERNEL);
388 if (!ww_acquire_ctxs)
389 VERBOSE_TOROUT_STRING("ww_acquire_ctx: Out of memory");
390}
391
392static void torture_ww_mutex_exit(void)
393{
394 kfree(ww_acquire_ctxs);
395}
396
397static int torture_ww_mutex_lock(int tid)
398__acquires(torture_ww_mutex_0)
399__acquires(torture_ww_mutex_1)
400__acquires(torture_ww_mutex_2)
401{
402 LIST_HEAD(list);
403 struct reorder_lock {
404 struct list_head link;
405 struct ww_mutex *lock;
406 } locks[3], *ll, *ln;
407 struct ww_acquire_ctx *ctx = &ww_acquire_ctxs[tid];
408
409 locks[0].lock = &torture_ww_mutex_0;
410 list_add(&locks[0].link, &list);
411
412 locks[1].lock = &torture_ww_mutex_1;
413 list_add(&locks[1].link, &list);
414
415 locks[2].lock = &torture_ww_mutex_2;
416 list_add(&locks[2].link, &list);
417
418 ww_acquire_init(ctx, &torture_ww_class);
419
420 list_for_each_entry(ll, &list, link) {
421 int err;
422
423 err = ww_mutex_lock(ll->lock, ctx);
424 if (!err)
425 continue;
426
427 ln = ll;
428 list_for_each_entry_continue_reverse(ln, &list, link)
429 ww_mutex_unlock(ln->lock);
430
431 if (err != -EDEADLK)
432 return err;
433
434 ww_mutex_lock_slow(ll->lock, ctx);
435 list_move(&ll->link, &list);
436 }
437
438 return 0;
439}
440
441static void torture_ww_mutex_unlock(int tid)
442__releases(torture_ww_mutex_0)
443__releases(torture_ww_mutex_1)
444__releases(torture_ww_mutex_2)
445{
446 struct ww_acquire_ctx *ctx = &ww_acquire_ctxs[tid];
447
448 ww_mutex_unlock(&torture_ww_mutex_0);
449 ww_mutex_unlock(&torture_ww_mutex_1);
450 ww_mutex_unlock(&torture_ww_mutex_2);
451 ww_acquire_fini(ctx);
452}
453
454static struct lock_torture_ops ww_mutex_lock_ops = {
455 .init = torture_ww_mutex_init,
456 .exit = torture_ww_mutex_exit,
457 .writelock = torture_ww_mutex_lock,
458 .write_delay = torture_mutex_delay,
459 .task_boost = torture_boost_dummy,
460 .writeunlock = torture_ww_mutex_unlock,
461 .readlock = NULL,
462 .read_delay = NULL,
463 .readunlock = NULL,
464 .name = "ww_mutex_lock"
465};
466
467#ifdef CONFIG_RT_MUTEXES
468static DEFINE_RT_MUTEX(torture_rtmutex);
469
470static int torture_rtmutex_lock(int tid __maybe_unused)
471__acquires(torture_rtmutex)
472{
473 rt_mutex_lock(&torture_rtmutex);
474 return 0;
475}
476
477static void torture_rtmutex_boost(struct torture_random_state *trsp)
478{
479 const unsigned int factor = 50000; /* yes, quite arbitrary */
480
481 if (!rt_task(current)) {
482 /*
483 * Boost priority once every ~50k operations. When the
484 * task tries to take the lock, the rtmutex it will account
485 * for the new priority, and do any corresponding pi-dance.
486 */
487 if (trsp && !(torture_random(trsp) %
488 (cxt.nrealwriters_stress * factor))) {
489 sched_set_fifo(current);
490 } else /* common case, do nothing */
491 return;
492 } else {
493 /*
494 * The task will remain boosted for another ~500k operations,
495 * then restored back to its original prio, and so forth.
496 *
497 * When @trsp is nil, we want to force-reset the task for
498 * stopping the kthread.
499 */
500 if (!trsp || !(torture_random(trsp) %
501 (cxt.nrealwriters_stress * factor * 2))) {
502 sched_set_normal(current, 0);
503 } else /* common case, do nothing */
504 return;
505 }
506}
507
508static void torture_rtmutex_delay(struct torture_random_state *trsp)
509{
510 const unsigned long shortdelay_us = 2;
511 const unsigned long longdelay_ms = 100;
512
513 /*
514 * We want a short delay mostly to emulate likely code, and
515 * we want a long delay occasionally to force massive contention.
516 */
517 if (!(torture_random(trsp) %
518 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
519 mdelay(longdelay_ms);
520 if (!(torture_random(trsp) %
521 (cxt.nrealwriters_stress * 2 * shortdelay_us)))
522 udelay(shortdelay_us);
523 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
524 torture_preempt_schedule(); /* Allow test to be preempted. */
525}
526
527static void torture_rtmutex_unlock(int tid __maybe_unused)
528__releases(torture_rtmutex)
529{
530 rt_mutex_unlock(&torture_rtmutex);
531}
532
533static struct lock_torture_ops rtmutex_lock_ops = {
534 .writelock = torture_rtmutex_lock,
535 .write_delay = torture_rtmutex_delay,
536 .task_boost = torture_rtmutex_boost,
537 .writeunlock = torture_rtmutex_unlock,
538 .readlock = NULL,
539 .read_delay = NULL,
540 .readunlock = NULL,
541 .name = "rtmutex_lock"
542};
543#endif
544
545static DECLARE_RWSEM(torture_rwsem);
546static int torture_rwsem_down_write(int tid __maybe_unused)
547__acquires(torture_rwsem)
548{
549 down_write(&torture_rwsem);
550 return 0;
551}
552
553static void torture_rwsem_write_delay(struct torture_random_state *trsp)
554{
555 const unsigned long longdelay_ms = 100;
556
557 /* We want a long delay occasionally to force massive contention. */
558 if (!(torture_random(trsp) %
559 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
560 mdelay(longdelay_ms * 10);
561 else
562 mdelay(longdelay_ms / 10);
563 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
564 torture_preempt_schedule(); /* Allow test to be preempted. */
565}
566
567static void torture_rwsem_up_write(int tid __maybe_unused)
568__releases(torture_rwsem)
569{
570 up_write(&torture_rwsem);
571}
572
573static int torture_rwsem_down_read(int tid __maybe_unused)
574__acquires(torture_rwsem)
575{
576 down_read(&torture_rwsem);
577 return 0;
578}
579
580static void torture_rwsem_read_delay(struct torture_random_state *trsp)
581{
582 const unsigned long longdelay_ms = 100;
583
584 /* We want a long delay occasionally to force massive contention. */
585 if (!(torture_random(trsp) %
586 (cxt.nrealreaders_stress * 2000 * longdelay_ms)))
587 mdelay(longdelay_ms * 2);
588 else
589 mdelay(longdelay_ms / 2);
590 if (!(torture_random(trsp) % (cxt.nrealreaders_stress * 20000)))
591 torture_preempt_schedule(); /* Allow test to be preempted. */
592}
593
594static void torture_rwsem_up_read(int tid __maybe_unused)
595__releases(torture_rwsem)
596{
597 up_read(&torture_rwsem);
598}
599
600static struct lock_torture_ops rwsem_lock_ops = {
601 .writelock = torture_rwsem_down_write,
602 .write_delay = torture_rwsem_write_delay,
603 .task_boost = torture_boost_dummy,
604 .writeunlock = torture_rwsem_up_write,
605 .readlock = torture_rwsem_down_read,
606 .read_delay = torture_rwsem_read_delay,
607 .readunlock = torture_rwsem_up_read,
608 .name = "rwsem_lock"
609};
610
611#include <linux/percpu-rwsem.h>
612static struct percpu_rw_semaphore pcpu_rwsem;
613
614static void torture_percpu_rwsem_init(void)
615{
616 BUG_ON(percpu_init_rwsem(&pcpu_rwsem));
617}
618
619static void torture_percpu_rwsem_exit(void)
620{
621 percpu_free_rwsem(&pcpu_rwsem);
622}
623
624static int torture_percpu_rwsem_down_write(int tid __maybe_unused)
625__acquires(pcpu_rwsem)
626{
627 percpu_down_write(&pcpu_rwsem);
628 return 0;
629}
630
631static void torture_percpu_rwsem_up_write(int tid __maybe_unused)
632__releases(pcpu_rwsem)
633{
634 percpu_up_write(&pcpu_rwsem);
635}
636
637static int torture_percpu_rwsem_down_read(int tid __maybe_unused)
638__acquires(pcpu_rwsem)
639{
640 percpu_down_read(&pcpu_rwsem);
641 return 0;
642}
643
644static void torture_percpu_rwsem_up_read(int tid __maybe_unused)
645__releases(pcpu_rwsem)
646{
647 percpu_up_read(&pcpu_rwsem);
648}
649
650static struct lock_torture_ops percpu_rwsem_lock_ops = {
651 .init = torture_percpu_rwsem_init,
652 .exit = torture_percpu_rwsem_exit,
653 .writelock = torture_percpu_rwsem_down_write,
654 .write_delay = torture_rwsem_write_delay,
655 .task_boost = torture_boost_dummy,
656 .writeunlock = torture_percpu_rwsem_up_write,
657 .readlock = torture_percpu_rwsem_down_read,
658 .read_delay = torture_rwsem_read_delay,
659 .readunlock = torture_percpu_rwsem_up_read,
660 .name = "percpu_rwsem_lock"
661};
662
663/*
664 * Lock torture writer kthread. Repeatedly acquires and releases
665 * the lock, checking for duplicate acquisitions.
666 */
667static int lock_torture_writer(void *arg)
668{
669 struct lock_stress_stats *lwsp = arg;
670 int tid = lwsp - cxt.lwsa;
671 DEFINE_TORTURE_RANDOM(rand);
672
673 VERBOSE_TOROUT_STRING("lock_torture_writer task started");
674 set_user_nice(current, MAX_NICE);
675
676 do {
677 if ((torture_random(&rand) & 0xfffff) == 0)
678 schedule_timeout_uninterruptible(1);
679
680 cxt.cur_ops->task_boost(&rand);
681 cxt.cur_ops->writelock(tid);
682 if (WARN_ON_ONCE(lock_is_write_held))
683 lwsp->n_lock_fail++;
684 lock_is_write_held = true;
685 if (WARN_ON_ONCE(lock_is_read_held))
686 lwsp->n_lock_fail++; /* rare, but... */
687
688 lwsp->n_lock_acquired++;
689 cxt.cur_ops->write_delay(&rand);
690 lock_is_write_held = false;
691 WRITE_ONCE(last_lock_release, jiffies);
692 cxt.cur_ops->writeunlock(tid);
693
694 stutter_wait("lock_torture_writer");
695 } while (!torture_must_stop());
696
697 cxt.cur_ops->task_boost(NULL); /* reset prio */
698 torture_kthread_stopping("lock_torture_writer");
699 return 0;
700}
701
702/*
703 * Lock torture reader kthread. Repeatedly acquires and releases
704 * the reader lock.
705 */
706static int lock_torture_reader(void *arg)
707{
708 struct lock_stress_stats *lrsp = arg;
709 int tid = lrsp - cxt.lrsa;
710 DEFINE_TORTURE_RANDOM(rand);
711
712 VERBOSE_TOROUT_STRING("lock_torture_reader task started");
713 set_user_nice(current, MAX_NICE);
714
715 do {
716 if ((torture_random(&rand) & 0xfffff) == 0)
717 schedule_timeout_uninterruptible(1);
718
719 cxt.cur_ops->readlock(tid);
720 lock_is_read_held = true;
721 if (WARN_ON_ONCE(lock_is_write_held))
722 lrsp->n_lock_fail++; /* rare, but... */
723
724 lrsp->n_lock_acquired++;
725 cxt.cur_ops->read_delay(&rand);
726 lock_is_read_held = false;
727 cxt.cur_ops->readunlock(tid);
728
729 stutter_wait("lock_torture_reader");
730 } while (!torture_must_stop());
731 torture_kthread_stopping("lock_torture_reader");
732 return 0;
733}
734
735/*
736 * Create an lock-torture-statistics message in the specified buffer.
737 */
738static void __torture_print_stats(char *page,
739 struct lock_stress_stats *statp, bool write)
740{
741 bool fail = false;
742 int i, n_stress;
743 long max = 0, min = statp ? statp[0].n_lock_acquired : 0;
744 long long sum = 0;
745
746 n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress;
747 for (i = 0; i < n_stress; i++) {
748 if (statp[i].n_lock_fail)
749 fail = true;
750 sum += statp[i].n_lock_acquired;
751 if (max < statp[i].n_lock_acquired)
752 max = statp[i].n_lock_acquired;
753 if (min > statp[i].n_lock_acquired)
754 min = statp[i].n_lock_acquired;
755 }
756 page += sprintf(page,
757 "%s: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n",
758 write ? "Writes" : "Reads ",
759 sum, max, min,
760 !onoff_interval && max / 2 > min ? "???" : "",
761 fail, fail ? "!!!" : "");
762 if (fail)
763 atomic_inc(&cxt.n_lock_torture_errors);
764}
765
766/*
767 * Print torture statistics. Caller must ensure that there is only one
768 * call to this function at a given time!!! This is normally accomplished
769 * by relying on the module system to only have one copy of the module
770 * loaded, and then by giving the lock_torture_stats kthread full control
771 * (or the init/cleanup functions when lock_torture_stats thread is not
772 * running).
773 */
774static void lock_torture_stats_print(void)
775{
776 int size = cxt.nrealwriters_stress * 200 + 8192;
777 char *buf;
778
779 if (cxt.cur_ops->readlock)
780 size += cxt.nrealreaders_stress * 200 + 8192;
781
782 buf = kmalloc(size, GFP_KERNEL);
783 if (!buf) {
784 pr_err("lock_torture_stats_print: Out of memory, need: %d",
785 size);
786 return;
787 }
788
789 __torture_print_stats(buf, cxt.lwsa, true);
790 pr_alert("%s", buf);
791 kfree(buf);
792
793 if (cxt.cur_ops->readlock) {
794 buf = kmalloc(size, GFP_KERNEL);
795 if (!buf) {
796 pr_err("lock_torture_stats_print: Out of memory, need: %d",
797 size);
798 return;
799 }
800
801 __torture_print_stats(buf, cxt.lrsa, false);
802 pr_alert("%s", buf);
803 kfree(buf);
804 }
805}
806
807/*
808 * Periodically prints torture statistics, if periodic statistics printing
809 * was specified via the stat_interval module parameter.
810 *
811 * No need to worry about fullstop here, since this one doesn't reference
812 * volatile state or register callbacks.
813 */
814static int lock_torture_stats(void *arg)
815{
816 VERBOSE_TOROUT_STRING("lock_torture_stats task started");
817 do {
818 schedule_timeout_interruptible(stat_interval * HZ);
819 lock_torture_stats_print();
820 torture_shutdown_absorb("lock_torture_stats");
821 } while (!torture_must_stop());
822 torture_kthread_stopping("lock_torture_stats");
823 return 0;
824}
825
826static inline void
827lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
828 const char *tag)
829{
830 pr_alert("%s" TORTURE_FLAG
831 "--- %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",
832 torture_type, tag, cxt.debug_lock ? " [debug]": "",
833 cxt.nrealwriters_stress, cxt.nrealreaders_stress, stat_interval,
834 verbose, shuffle_interval, stutter, shutdown_secs,
835 onoff_interval, onoff_holdoff);
836}
837
838static void lock_torture_cleanup(void)
839{
840 int i;
841
842 if (torture_cleanup_begin())
843 return;
844
845 /*
846 * Indicates early cleanup, meaning that the test has not run,
847 * such as when passing bogus args when loading the module.
848 * However cxt->cur_ops.init() may have been invoked, so beside
849 * perform the underlying torture-specific cleanups, cur_ops.exit()
850 * will be invoked if needed.
851 */
852 if (!cxt.lwsa && !cxt.lrsa)
853 goto end;
854
855 if (writer_tasks) {
856 for (i = 0; i < cxt.nrealwriters_stress; i++)
857 torture_stop_kthread(lock_torture_writer,
858 writer_tasks[i]);
859 kfree(writer_tasks);
860 writer_tasks = NULL;
861 }
862
863 if (reader_tasks) {
864 for (i = 0; i < cxt.nrealreaders_stress; i++)
865 torture_stop_kthread(lock_torture_reader,
866 reader_tasks[i]);
867 kfree(reader_tasks);
868 reader_tasks = NULL;
869 }
870
871 torture_stop_kthread(lock_torture_stats, stats_task);
872 lock_torture_stats_print(); /* -After- the stats thread is stopped! */
873
874 if (atomic_read(&cxt.n_lock_torture_errors))
875 lock_torture_print_module_parms(cxt.cur_ops,
876 "End of test: FAILURE");
877 else if (torture_onoff_failures())
878 lock_torture_print_module_parms(cxt.cur_ops,
879 "End of test: LOCK_HOTPLUG");
880 else
881 lock_torture_print_module_parms(cxt.cur_ops,
882 "End of test: SUCCESS");
883
884 kfree(cxt.lwsa);
885 cxt.lwsa = NULL;
886 kfree(cxt.lrsa);
887 cxt.lrsa = NULL;
888
889end:
890 if (cxt.init_called) {
891 if (cxt.cur_ops->exit)
892 cxt.cur_ops->exit();
893 cxt.init_called = false;
894 }
895 torture_cleanup_end();
896}
897
898static int __init lock_torture_init(void)
899{
900 int i, j;
901 int firsterr = 0;
902 static struct lock_torture_ops *torture_ops[] = {
903 &lock_busted_ops,
904 &spin_lock_ops, &spin_lock_irq_ops,
905 &rw_lock_ops, &rw_lock_irq_ops,
906 &mutex_lock_ops,
907 &ww_mutex_lock_ops,
908#ifdef CONFIG_RT_MUTEXES
909 &rtmutex_lock_ops,
910#endif
911 &rwsem_lock_ops,
912 &percpu_rwsem_lock_ops,
913 };
914
915 if (!torture_init_begin(torture_type, verbose))
916 return -EBUSY;
917
918 /* Process args and tell the world that the torturer is on the job. */
919 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
920 cxt.cur_ops = torture_ops[i];
921 if (strcmp(torture_type, cxt.cur_ops->name) == 0)
922 break;
923 }
924 if (i == ARRAY_SIZE(torture_ops)) {
925 pr_alert("lock-torture: invalid torture type: \"%s\"\n",
926 torture_type);
927 pr_alert("lock-torture types:");
928 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
929 pr_alert(" %s", torture_ops[i]->name);
930 pr_alert("\n");
931 firsterr = -EINVAL;
932 goto unwind;
933 }
934
935 if (nwriters_stress == 0 &&
936 (!cxt.cur_ops->readlock || nreaders_stress == 0)) {
937 pr_alert("lock-torture: must run at least one locking thread\n");
938 firsterr = -EINVAL;
939 goto unwind;
940 }
941
942 if (nwriters_stress >= 0)
943 cxt.nrealwriters_stress = nwriters_stress;
944 else
945 cxt.nrealwriters_stress = 2 * num_online_cpus();
946
947 if (cxt.cur_ops->init) {
948 cxt.cur_ops->init();
949 cxt.init_called = true;
950 }
951
952#ifdef CONFIG_DEBUG_MUTEXES
953 if (str_has_prefix(torture_type, "mutex"))
954 cxt.debug_lock = true;
955#endif
956#ifdef CONFIG_DEBUG_RT_MUTEXES
957 if (str_has_prefix(torture_type, "rtmutex"))
958 cxt.debug_lock = true;
959#endif
960#ifdef CONFIG_DEBUG_SPINLOCK
961 if ((str_has_prefix(torture_type, "spin")) ||
962 (str_has_prefix(torture_type, "rw_lock")))
963 cxt.debug_lock = true;
964#endif
965
966 /* Initialize the statistics so that each run gets its own numbers. */
967 if (nwriters_stress) {
968 lock_is_write_held = false;
969 cxt.lwsa = kmalloc_array(cxt.nrealwriters_stress,
970 sizeof(*cxt.lwsa),
971 GFP_KERNEL);
972 if (cxt.lwsa == NULL) {
973 VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory");
974 firsterr = -ENOMEM;
975 goto unwind;
976 }
977
978 for (i = 0; i < cxt.nrealwriters_stress; i++) {
979 cxt.lwsa[i].n_lock_fail = 0;
980 cxt.lwsa[i].n_lock_acquired = 0;
981 }
982 }
983
984 if (cxt.cur_ops->readlock) {
985 if (nreaders_stress >= 0)
986 cxt.nrealreaders_stress = nreaders_stress;
987 else {
988 /*
989 * By default distribute evenly the number of
990 * readers and writers. We still run the same number
991 * of threads as the writer-only locks default.
992 */
993 if (nwriters_stress < 0) /* user doesn't care */
994 cxt.nrealwriters_stress = num_online_cpus();
995 cxt.nrealreaders_stress = cxt.nrealwriters_stress;
996 }
997
998 if (nreaders_stress) {
999 lock_is_read_held = false;
1000 cxt.lrsa = kmalloc_array(cxt.nrealreaders_stress,
1001 sizeof(*cxt.lrsa),
1002 GFP_KERNEL);
1003 if (cxt.lrsa == NULL) {
1004 VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory");
1005 firsterr = -ENOMEM;
1006 kfree(cxt.lwsa);
1007 cxt.lwsa = NULL;
1008 goto unwind;
1009 }
1010
1011 for (i = 0; i < cxt.nrealreaders_stress; i++) {
1012 cxt.lrsa[i].n_lock_fail = 0;
1013 cxt.lrsa[i].n_lock_acquired = 0;
1014 }
1015 }
1016 }
1017
1018 lock_torture_print_module_parms(cxt.cur_ops, "Start of test");
1019
1020 /* Prepare torture context. */
1021 if (onoff_interval > 0) {
1022 firsterr = torture_onoff_init(onoff_holdoff * HZ,
1023 onoff_interval * HZ, NULL);
1024 if (firsterr)
1025 goto unwind;
1026 }
1027 if (shuffle_interval > 0) {
1028 firsterr = torture_shuffle_init(shuffle_interval);
1029 if (firsterr)
1030 goto unwind;
1031 }
1032 if (shutdown_secs > 0) {
1033 firsterr = torture_shutdown_init(shutdown_secs,
1034 lock_torture_cleanup);
1035 if (firsterr)
1036 goto unwind;
1037 }
1038 if (stutter > 0) {
1039 firsterr = torture_stutter_init(stutter, stutter);
1040 if (firsterr)
1041 goto unwind;
1042 }
1043
1044 if (nwriters_stress) {
1045 writer_tasks = kcalloc(cxt.nrealwriters_stress,
1046 sizeof(writer_tasks[0]),
1047 GFP_KERNEL);
1048 if (writer_tasks == NULL) {
1049 VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory");
1050 firsterr = -ENOMEM;
1051 goto unwind;
1052 }
1053 }
1054
1055 if (cxt.cur_ops->readlock) {
1056 reader_tasks = kcalloc(cxt.nrealreaders_stress,
1057 sizeof(reader_tasks[0]),
1058 GFP_KERNEL);
1059 if (reader_tasks == NULL) {
1060 VERBOSE_TOROUT_ERRSTRING("reader_tasks: Out of memory");
1061 kfree(writer_tasks);
1062 writer_tasks = NULL;
1063 firsterr = -ENOMEM;
1064 goto unwind;
1065 }
1066 }
1067
1068 /*
1069 * Create the kthreads and start torturing (oh, those poor little locks).
1070 *
1071 * TODO: Note that we interleave writers with readers, giving writers a
1072 * slight advantage, by creating its kthread first. This can be modified
1073 * for very specific needs, or even let the user choose the policy, if
1074 * ever wanted.
1075 */
1076 for (i = 0, j = 0; i < cxt.nrealwriters_stress ||
1077 j < cxt.nrealreaders_stress; i++, j++) {
1078 if (i >= cxt.nrealwriters_stress)
1079 goto create_reader;
1080
1081 /* Create writer. */
1082 firsterr = torture_create_kthread(lock_torture_writer, &cxt.lwsa[i],
1083 writer_tasks[i]);
1084 if (firsterr)
1085 goto unwind;
1086
1087 create_reader:
1088 if (cxt.cur_ops->readlock == NULL || (j >= cxt.nrealreaders_stress))
1089 continue;
1090 /* Create reader. */
1091 firsterr = torture_create_kthread(lock_torture_reader, &cxt.lrsa[j],
1092 reader_tasks[j]);
1093 if (firsterr)
1094 goto unwind;
1095 }
1096 if (stat_interval > 0) {
1097 firsterr = torture_create_kthread(lock_torture_stats, NULL,
1098 stats_task);
1099 if (firsterr)
1100 goto unwind;
1101 }
1102 torture_init_end();
1103 return 0;
1104
1105unwind:
1106 torture_init_end();
1107 lock_torture_cleanup();
1108 if (shutdown_secs) {
1109 WARN_ON(!IS_MODULE(CONFIG_LOCK_TORTURE_TEST));
1110 kernel_power_off();
1111 }
1112 return firsterr;
1113}
1114
1115module_init(lock_torture_init);
1116module_exit(lock_torture_cleanup);