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