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
33 MODULE_LICENSE("GPL");
34 MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>");
35
36 torture_param(int, nwriters_stress, -1,
37 "Number of write-locking stress-test threads");
38 torture_param(int, nreaders_stress, -1,
39 "Number of read-locking stress-test threads");
40 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
41 torture_param(int, onoff_interval, 0,
42 "Time between CPU hotplugs (s), 0=disable");
43 torture_param(int, shuffle_interval, 3,
44 "Number of jiffies between shuffles, 0=disable");
45 torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable.");
46 torture_param(int, stat_interval, 60,
47 "Number of seconds between stats printk()s");
48 torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
49 torture_param(int, rt_boost, 2,
50 "Do periodic rt-boost. 0=Disable, 1=Only for rt_mutex, 2=For all lock types.");
51 torture_param(int, rt_boost_factor, 50, "A factor determining how often rt-boost happens.");
52 torture_param(int, verbose, 1,
53 "Enable verbose debugging printk()s");
54
55 static char *torture_type = "spin_lock";
56 module_param(torture_type, charp, 0444);
57 MODULE_PARM_DESC(torture_type,
58 "Type of lock to torture (spin_lock, spin_lock_irq, mutex_lock, ...)");
59
60 static struct task_struct *stats_task;
61 static struct task_struct **writer_tasks;
62 static struct task_struct **reader_tasks;
63
64 static bool lock_is_write_held;
65 static atomic_t lock_is_read_held;
66 static unsigned long last_lock_release;
67
68 struct lock_stress_stats {
69 long n_lock_fail;
70 long n_lock_acquired;
71 };
72
73 /* Forward reference. */
74 static void lock_torture_cleanup(void);
75
76 /*
77 * Operations vector for selecting different types of tests.
78 */
79 struct lock_torture_ops {
80 void (*init)(void);
81 void (*exit)(void);
82 int (*writelock)(int tid);
83 void (*write_delay)(struct torture_random_state *trsp);
84 void (*task_boost)(struct torture_random_state *trsp);
85 void (*writeunlock)(int tid);
86 int (*readlock)(int tid);
87 void (*read_delay)(struct torture_random_state *trsp);
88 void (*readunlock)(int tid);
89
90 unsigned long flags; /* for irq spinlocks */
91 const char *name;
92 };
93
94 struct lock_torture_cxt {
95 int nrealwriters_stress;
96 int nrealreaders_stress;
97 bool debug_lock;
98 bool init_called;
99 atomic_t n_lock_torture_errors;
100 struct lock_torture_ops *cur_ops;
101 struct lock_stress_stats *lwsa; /* writer statistics */
102 struct lock_stress_stats *lrsa; /* reader statistics */
103 };
104 static struct lock_torture_cxt cxt = { 0, 0, false, false,
105 ATOMIC_INIT(0),
106 NULL, NULL};
107 /*
108 * Definitions for lock torture testing.
109 */
110
torture_lock_busted_write_lock(int tid __maybe_unused)111 static int torture_lock_busted_write_lock(int tid __maybe_unused)
112 {
113 return 0; /* BUGGY, do not use in real life!!! */
114 }
115
torture_lock_busted_write_delay(struct torture_random_state * trsp)116 static void torture_lock_busted_write_delay(struct torture_random_state *trsp)
117 {
118 const unsigned long longdelay_ms = 100;
119
120 /* We want a long delay occasionally to force massive contention. */
121 if (!(torture_random(trsp) %
122 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
123 mdelay(longdelay_ms);
124 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
125 torture_preempt_schedule(); /* Allow test to be preempted. */
126 }
127
torture_lock_busted_write_unlock(int tid __maybe_unused)128 static void torture_lock_busted_write_unlock(int tid __maybe_unused)
129 {
130 /* BUGGY, do not use in real life!!! */
131 }
132
__torture_rt_boost(struct torture_random_state * trsp)133 static void __torture_rt_boost(struct torture_random_state *trsp)
134 {
135 const unsigned int factor = rt_boost_factor;
136
137 if (!rt_task(current)) {
138 /*
139 * Boost priority once every rt_boost_factor operations. When
140 * the task tries to take the lock, the rtmutex it will account
141 * for the new priority, and do any corresponding pi-dance.
142 */
143 if (trsp && !(torture_random(trsp) %
144 (cxt.nrealwriters_stress * factor))) {
145 sched_set_fifo(current);
146 } else /* common case, do nothing */
147 return;
148 } else {
149 /*
150 * The task will remain boosted for another 10 * rt_boost_factor
151 * operations, then restored back to its original prio, and so
152 * forth.
153 *
154 * When @trsp is nil, we want to force-reset the task for
155 * stopping the kthread.
156 */
157 if (!trsp || !(torture_random(trsp) %
158 (cxt.nrealwriters_stress * factor * 2))) {
159 sched_set_normal(current, 0);
160 } else /* common case, do nothing */
161 return;
162 }
163 }
164
torture_rt_boost(struct torture_random_state * trsp)165 static void torture_rt_boost(struct torture_random_state *trsp)
166 {
167 if (rt_boost != 2)
168 return;
169
170 __torture_rt_boost(trsp);
171 }
172
173 static struct lock_torture_ops lock_busted_ops = {
174 .writelock = torture_lock_busted_write_lock,
175 .write_delay = torture_lock_busted_write_delay,
176 .task_boost = torture_rt_boost,
177 .writeunlock = torture_lock_busted_write_unlock,
178 .readlock = NULL,
179 .read_delay = NULL,
180 .readunlock = NULL,
181 .name = "lock_busted"
182 };
183
184 static DEFINE_SPINLOCK(torture_spinlock);
185
torture_spin_lock_write_lock(int tid __maybe_unused)186 static int torture_spin_lock_write_lock(int tid __maybe_unused)
187 __acquires(torture_spinlock)
188 {
189 spin_lock(&torture_spinlock);
190 return 0;
191 }
192
torture_spin_lock_write_delay(struct torture_random_state * trsp)193 static void torture_spin_lock_write_delay(struct torture_random_state *trsp)
194 {
195 const unsigned long shortdelay_us = 2;
196 const unsigned long longdelay_ms = 100;
197
198 /* We want a short delay mostly to emulate likely code, and
199 * we want a long delay occasionally to force massive contention.
200 */
201 if (!(torture_random(trsp) %
202 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
203 mdelay(longdelay_ms);
204 if (!(torture_random(trsp) %
205 (cxt.nrealwriters_stress * 2 * shortdelay_us)))
206 udelay(shortdelay_us);
207 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
208 torture_preempt_schedule(); /* Allow test to be preempted. */
209 }
210
torture_spin_lock_write_unlock(int tid __maybe_unused)211 static void torture_spin_lock_write_unlock(int tid __maybe_unused)
212 __releases(torture_spinlock)
213 {
214 spin_unlock(&torture_spinlock);
215 }
216
217 static struct lock_torture_ops spin_lock_ops = {
218 .writelock = torture_spin_lock_write_lock,
219 .write_delay = torture_spin_lock_write_delay,
220 .task_boost = torture_rt_boost,
221 .writeunlock = torture_spin_lock_write_unlock,
222 .readlock = NULL,
223 .read_delay = NULL,
224 .readunlock = NULL,
225 .name = "spin_lock"
226 };
227
torture_spin_lock_write_lock_irq(int tid __maybe_unused)228 static int torture_spin_lock_write_lock_irq(int tid __maybe_unused)
229 __acquires(torture_spinlock)
230 {
231 unsigned long flags;
232
233 spin_lock_irqsave(&torture_spinlock, flags);
234 cxt.cur_ops->flags = flags;
235 return 0;
236 }
237
torture_lock_spin_write_unlock_irq(int tid __maybe_unused)238 static void torture_lock_spin_write_unlock_irq(int tid __maybe_unused)
239 __releases(torture_spinlock)
240 {
241 spin_unlock_irqrestore(&torture_spinlock, cxt.cur_ops->flags);
242 }
243
244 static struct lock_torture_ops spin_lock_irq_ops = {
245 .writelock = torture_spin_lock_write_lock_irq,
246 .write_delay = torture_spin_lock_write_delay,
247 .task_boost = torture_rt_boost,
248 .writeunlock = torture_lock_spin_write_unlock_irq,
249 .readlock = NULL,
250 .read_delay = NULL,
251 .readunlock = NULL,
252 .name = "spin_lock_irq"
253 };
254
255 static DEFINE_RWLOCK(torture_rwlock);
256
torture_rwlock_write_lock(int tid __maybe_unused)257 static int torture_rwlock_write_lock(int tid __maybe_unused)
258 __acquires(torture_rwlock)
259 {
260 write_lock(&torture_rwlock);
261 return 0;
262 }
263
torture_rwlock_write_delay(struct torture_random_state * trsp)264 static void torture_rwlock_write_delay(struct torture_random_state *trsp)
265 {
266 const unsigned long shortdelay_us = 2;
267 const unsigned long longdelay_ms = 100;
268
269 /* We want a short delay mostly to emulate likely code, and
270 * we want a long delay occasionally to force massive contention.
271 */
272 if (!(torture_random(trsp) %
273 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
274 mdelay(longdelay_ms);
275 else
276 udelay(shortdelay_us);
277 }
278
torture_rwlock_write_unlock(int tid __maybe_unused)279 static void torture_rwlock_write_unlock(int tid __maybe_unused)
280 __releases(torture_rwlock)
281 {
282 write_unlock(&torture_rwlock);
283 }
284
torture_rwlock_read_lock(int tid __maybe_unused)285 static int torture_rwlock_read_lock(int tid __maybe_unused)
286 __acquires(torture_rwlock)
287 {
288 read_lock(&torture_rwlock);
289 return 0;
290 }
291
torture_rwlock_read_delay(struct torture_random_state * trsp)292 static void torture_rwlock_read_delay(struct torture_random_state *trsp)
293 {
294 const unsigned long shortdelay_us = 10;
295 const unsigned long longdelay_ms = 100;
296
297 /* We want a short delay mostly to emulate likely code, and
298 * we want a long delay occasionally to force massive contention.
299 */
300 if (!(torture_random(trsp) %
301 (cxt.nrealreaders_stress * 2000 * longdelay_ms)))
302 mdelay(longdelay_ms);
303 else
304 udelay(shortdelay_us);
305 }
306
torture_rwlock_read_unlock(int tid __maybe_unused)307 static void torture_rwlock_read_unlock(int tid __maybe_unused)
308 __releases(torture_rwlock)
309 {
310 read_unlock(&torture_rwlock);
311 }
312
313 static struct lock_torture_ops rw_lock_ops = {
314 .writelock = torture_rwlock_write_lock,
315 .write_delay = torture_rwlock_write_delay,
316 .task_boost = torture_rt_boost,
317 .writeunlock = torture_rwlock_write_unlock,
318 .readlock = torture_rwlock_read_lock,
319 .read_delay = torture_rwlock_read_delay,
320 .readunlock = torture_rwlock_read_unlock,
321 .name = "rw_lock"
322 };
323
torture_rwlock_write_lock_irq(int tid __maybe_unused)324 static int torture_rwlock_write_lock_irq(int tid __maybe_unused)
325 __acquires(torture_rwlock)
326 {
327 unsigned long flags;
328
329 write_lock_irqsave(&torture_rwlock, flags);
330 cxt.cur_ops->flags = flags;
331 return 0;
332 }
333
torture_rwlock_write_unlock_irq(int tid __maybe_unused)334 static void torture_rwlock_write_unlock_irq(int tid __maybe_unused)
335 __releases(torture_rwlock)
336 {
337 write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
338 }
339
torture_rwlock_read_lock_irq(int tid __maybe_unused)340 static int torture_rwlock_read_lock_irq(int tid __maybe_unused)
341 __acquires(torture_rwlock)
342 {
343 unsigned long flags;
344
345 read_lock_irqsave(&torture_rwlock, flags);
346 cxt.cur_ops->flags = flags;
347 return 0;
348 }
349
torture_rwlock_read_unlock_irq(int tid __maybe_unused)350 static void torture_rwlock_read_unlock_irq(int tid __maybe_unused)
351 __releases(torture_rwlock)
352 {
353 read_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
354 }
355
356 static struct lock_torture_ops rw_lock_irq_ops = {
357 .writelock = torture_rwlock_write_lock_irq,
358 .write_delay = torture_rwlock_write_delay,
359 .task_boost = torture_rt_boost,
360 .writeunlock = torture_rwlock_write_unlock_irq,
361 .readlock = torture_rwlock_read_lock_irq,
362 .read_delay = torture_rwlock_read_delay,
363 .readunlock = torture_rwlock_read_unlock_irq,
364 .name = "rw_lock_irq"
365 };
366
367 static DEFINE_MUTEX(torture_mutex);
368
torture_mutex_lock(int tid __maybe_unused)369 static int torture_mutex_lock(int tid __maybe_unused)
370 __acquires(torture_mutex)
371 {
372 mutex_lock(&torture_mutex);
373 return 0;
374 }
375
torture_mutex_delay(struct torture_random_state * trsp)376 static void torture_mutex_delay(struct torture_random_state *trsp)
377 {
378 const unsigned long longdelay_ms = 100;
379
380 /* We want a long delay occasionally to force massive contention. */
381 if (!(torture_random(trsp) %
382 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
383 mdelay(longdelay_ms * 5);
384 else
385 mdelay(longdelay_ms / 5);
386 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
387 torture_preempt_schedule(); /* Allow test to be preempted. */
388 }
389
torture_mutex_unlock(int tid __maybe_unused)390 static void torture_mutex_unlock(int tid __maybe_unused)
391 __releases(torture_mutex)
392 {
393 mutex_unlock(&torture_mutex);
394 }
395
396 static struct lock_torture_ops mutex_lock_ops = {
397 .writelock = torture_mutex_lock,
398 .write_delay = torture_mutex_delay,
399 .task_boost = torture_rt_boost,
400 .writeunlock = torture_mutex_unlock,
401 .readlock = NULL,
402 .read_delay = NULL,
403 .readunlock = NULL,
404 .name = "mutex_lock"
405 };
406
407 #include <linux/ww_mutex.h>
408 /*
409 * The torture ww_mutexes should belong to the same lock class as
410 * torture_ww_class to avoid lockdep problem. The ww_mutex_init()
411 * function is called for initialization to ensure that.
412 */
413 static DEFINE_WD_CLASS(torture_ww_class);
414 static struct ww_mutex torture_ww_mutex_0, torture_ww_mutex_1, torture_ww_mutex_2;
415 static struct ww_acquire_ctx *ww_acquire_ctxs;
416
torture_ww_mutex_init(void)417 static void torture_ww_mutex_init(void)
418 {
419 ww_mutex_init(&torture_ww_mutex_0, &torture_ww_class);
420 ww_mutex_init(&torture_ww_mutex_1, &torture_ww_class);
421 ww_mutex_init(&torture_ww_mutex_2, &torture_ww_class);
422
423 ww_acquire_ctxs = kmalloc_array(cxt.nrealwriters_stress,
424 sizeof(*ww_acquire_ctxs),
425 GFP_KERNEL);
426 if (!ww_acquire_ctxs)
427 VERBOSE_TOROUT_STRING("ww_acquire_ctx: Out of memory");
428 }
429
torture_ww_mutex_exit(void)430 static void torture_ww_mutex_exit(void)
431 {
432 kfree(ww_acquire_ctxs);
433 }
434
torture_ww_mutex_lock(int tid)435 static int torture_ww_mutex_lock(int tid)
436 __acquires(torture_ww_mutex_0)
437 __acquires(torture_ww_mutex_1)
438 __acquires(torture_ww_mutex_2)
439 {
440 LIST_HEAD(list);
441 struct reorder_lock {
442 struct list_head link;
443 struct ww_mutex *lock;
444 } locks[3], *ll, *ln;
445 struct ww_acquire_ctx *ctx = &ww_acquire_ctxs[tid];
446
447 locks[0].lock = &torture_ww_mutex_0;
448 list_add(&locks[0].link, &list);
449
450 locks[1].lock = &torture_ww_mutex_1;
451 list_add(&locks[1].link, &list);
452
453 locks[2].lock = &torture_ww_mutex_2;
454 list_add(&locks[2].link, &list);
455
456 ww_acquire_init(ctx, &torture_ww_class);
457
458 list_for_each_entry(ll, &list, link) {
459 int err;
460
461 err = ww_mutex_lock(ll->lock, ctx);
462 if (!err)
463 continue;
464
465 ln = ll;
466 list_for_each_entry_continue_reverse(ln, &list, link)
467 ww_mutex_unlock(ln->lock);
468
469 if (err != -EDEADLK)
470 return err;
471
472 ww_mutex_lock_slow(ll->lock, ctx);
473 list_move(&ll->link, &list);
474 }
475
476 return 0;
477 }
478
torture_ww_mutex_unlock(int tid)479 static void torture_ww_mutex_unlock(int tid)
480 __releases(torture_ww_mutex_0)
481 __releases(torture_ww_mutex_1)
482 __releases(torture_ww_mutex_2)
483 {
484 struct ww_acquire_ctx *ctx = &ww_acquire_ctxs[tid];
485
486 ww_mutex_unlock(&torture_ww_mutex_0);
487 ww_mutex_unlock(&torture_ww_mutex_1);
488 ww_mutex_unlock(&torture_ww_mutex_2);
489 ww_acquire_fini(ctx);
490 }
491
492 static struct lock_torture_ops ww_mutex_lock_ops = {
493 .init = torture_ww_mutex_init,
494 .exit = torture_ww_mutex_exit,
495 .writelock = torture_ww_mutex_lock,
496 .write_delay = torture_mutex_delay,
497 .task_boost = torture_rt_boost,
498 .writeunlock = torture_ww_mutex_unlock,
499 .readlock = NULL,
500 .read_delay = NULL,
501 .readunlock = NULL,
502 .name = "ww_mutex_lock"
503 };
504
505 #ifdef CONFIG_RT_MUTEXES
506 static DEFINE_RT_MUTEX(torture_rtmutex);
507
torture_rtmutex_lock(int tid __maybe_unused)508 static int torture_rtmutex_lock(int tid __maybe_unused)
509 __acquires(torture_rtmutex)
510 {
511 rt_mutex_lock(&torture_rtmutex);
512 return 0;
513 }
514
torture_rtmutex_delay(struct torture_random_state * trsp)515 static void torture_rtmutex_delay(struct torture_random_state *trsp)
516 {
517 const unsigned long shortdelay_us = 2;
518 const unsigned long longdelay_ms = 100;
519
520 /*
521 * We want a short delay mostly to emulate likely code, and
522 * we want a long delay occasionally to force massive contention.
523 */
524 if (!(torture_random(trsp) %
525 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
526 mdelay(longdelay_ms);
527 if (!(torture_random(trsp) %
528 (cxt.nrealwriters_stress * 2 * shortdelay_us)))
529 udelay(shortdelay_us);
530 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
531 torture_preempt_schedule(); /* Allow test to be preempted. */
532 }
533
torture_rtmutex_unlock(int tid __maybe_unused)534 static void torture_rtmutex_unlock(int tid __maybe_unused)
535 __releases(torture_rtmutex)
536 {
537 rt_mutex_unlock(&torture_rtmutex);
538 }
539
torture_rt_boost_rtmutex(struct torture_random_state * trsp)540 static void torture_rt_boost_rtmutex(struct torture_random_state *trsp)
541 {
542 if (!rt_boost)
543 return;
544
545 __torture_rt_boost(trsp);
546 }
547
548 static struct lock_torture_ops rtmutex_lock_ops = {
549 .writelock = torture_rtmutex_lock,
550 .write_delay = torture_rtmutex_delay,
551 .task_boost = torture_rt_boost_rtmutex,
552 .writeunlock = torture_rtmutex_unlock,
553 .readlock = NULL,
554 .read_delay = NULL,
555 .readunlock = NULL,
556 .name = "rtmutex_lock"
557 };
558 #endif
559
560 static DECLARE_RWSEM(torture_rwsem);
torture_rwsem_down_write(int tid __maybe_unused)561 static int torture_rwsem_down_write(int tid __maybe_unused)
562 __acquires(torture_rwsem)
563 {
564 down_write(&torture_rwsem);
565 return 0;
566 }
567
torture_rwsem_write_delay(struct torture_random_state * trsp)568 static void torture_rwsem_write_delay(struct torture_random_state *trsp)
569 {
570 const unsigned long longdelay_ms = 100;
571
572 /* We want a long delay occasionally to force massive contention. */
573 if (!(torture_random(trsp) %
574 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
575 mdelay(longdelay_ms * 10);
576 else
577 mdelay(longdelay_ms / 10);
578 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
579 torture_preempt_schedule(); /* Allow test to be preempted. */
580 }
581
torture_rwsem_up_write(int tid __maybe_unused)582 static void torture_rwsem_up_write(int tid __maybe_unused)
583 __releases(torture_rwsem)
584 {
585 up_write(&torture_rwsem);
586 }
587
torture_rwsem_down_read(int tid __maybe_unused)588 static int torture_rwsem_down_read(int tid __maybe_unused)
589 __acquires(torture_rwsem)
590 {
591 down_read(&torture_rwsem);
592 return 0;
593 }
594
torture_rwsem_read_delay(struct torture_random_state * trsp)595 static void torture_rwsem_read_delay(struct torture_random_state *trsp)
596 {
597 const unsigned long longdelay_ms = 100;
598
599 /* We want a long delay occasionally to force massive contention. */
600 if (!(torture_random(trsp) %
601 (cxt.nrealreaders_stress * 2000 * longdelay_ms)))
602 mdelay(longdelay_ms * 2);
603 else
604 mdelay(longdelay_ms / 2);
605 if (!(torture_random(trsp) % (cxt.nrealreaders_stress * 20000)))
606 torture_preempt_schedule(); /* Allow test to be preempted. */
607 }
608
torture_rwsem_up_read(int tid __maybe_unused)609 static void torture_rwsem_up_read(int tid __maybe_unused)
610 __releases(torture_rwsem)
611 {
612 up_read(&torture_rwsem);
613 }
614
615 static struct lock_torture_ops rwsem_lock_ops = {
616 .writelock = torture_rwsem_down_write,
617 .write_delay = torture_rwsem_write_delay,
618 .task_boost = torture_rt_boost,
619 .writeunlock = torture_rwsem_up_write,
620 .readlock = torture_rwsem_down_read,
621 .read_delay = torture_rwsem_read_delay,
622 .readunlock = torture_rwsem_up_read,
623 .name = "rwsem_lock"
624 };
625
626 #include <linux/percpu-rwsem.h>
627 static struct percpu_rw_semaphore pcpu_rwsem;
628
torture_percpu_rwsem_init(void)629 static void torture_percpu_rwsem_init(void)
630 {
631 BUG_ON(percpu_init_rwsem(&pcpu_rwsem));
632 }
633
torture_percpu_rwsem_exit(void)634 static void torture_percpu_rwsem_exit(void)
635 {
636 percpu_free_rwsem(&pcpu_rwsem);
637 }
638
torture_percpu_rwsem_down_write(int tid __maybe_unused)639 static int torture_percpu_rwsem_down_write(int tid __maybe_unused)
640 __acquires(pcpu_rwsem)
641 {
642 percpu_down_write(&pcpu_rwsem);
643 return 0;
644 }
645
torture_percpu_rwsem_up_write(int tid __maybe_unused)646 static void torture_percpu_rwsem_up_write(int tid __maybe_unused)
647 __releases(pcpu_rwsem)
648 {
649 percpu_up_write(&pcpu_rwsem);
650 }
651
torture_percpu_rwsem_down_read(int tid __maybe_unused)652 static int torture_percpu_rwsem_down_read(int tid __maybe_unused)
653 __acquires(pcpu_rwsem)
654 {
655 percpu_down_read(&pcpu_rwsem);
656 return 0;
657 }
658
torture_percpu_rwsem_up_read(int tid __maybe_unused)659 static void torture_percpu_rwsem_up_read(int tid __maybe_unused)
660 __releases(pcpu_rwsem)
661 {
662 percpu_up_read(&pcpu_rwsem);
663 }
664
665 static struct lock_torture_ops percpu_rwsem_lock_ops = {
666 .init = torture_percpu_rwsem_init,
667 .exit = torture_percpu_rwsem_exit,
668 .writelock = torture_percpu_rwsem_down_write,
669 .write_delay = torture_rwsem_write_delay,
670 .task_boost = torture_rt_boost,
671 .writeunlock = torture_percpu_rwsem_up_write,
672 .readlock = torture_percpu_rwsem_down_read,
673 .read_delay = torture_rwsem_read_delay,
674 .readunlock = torture_percpu_rwsem_up_read,
675 .name = "percpu_rwsem_lock"
676 };
677
678 /*
679 * Lock torture writer kthread. Repeatedly acquires and releases
680 * the lock, checking for duplicate acquisitions.
681 */
lock_torture_writer(void * arg)682 static int lock_torture_writer(void *arg)
683 {
684 struct lock_stress_stats *lwsp = arg;
685 int tid = lwsp - cxt.lwsa;
686 DEFINE_TORTURE_RANDOM(rand);
687
688 VERBOSE_TOROUT_STRING("lock_torture_writer task started");
689 set_user_nice(current, MAX_NICE);
690
691 do {
692 if ((torture_random(&rand) & 0xfffff) == 0)
693 schedule_timeout_uninterruptible(1);
694
695 cxt.cur_ops->task_boost(&rand);
696 cxt.cur_ops->writelock(tid);
697 if (WARN_ON_ONCE(lock_is_write_held))
698 lwsp->n_lock_fail++;
699 lock_is_write_held = true;
700 if (WARN_ON_ONCE(atomic_read(&lock_is_read_held)))
701 lwsp->n_lock_fail++; /* rare, but... */
702
703 lwsp->n_lock_acquired++;
704 cxt.cur_ops->write_delay(&rand);
705 lock_is_write_held = false;
706 WRITE_ONCE(last_lock_release, jiffies);
707 cxt.cur_ops->writeunlock(tid);
708
709 stutter_wait("lock_torture_writer");
710 } while (!torture_must_stop());
711
712 cxt.cur_ops->task_boost(NULL); /* reset prio */
713 torture_kthread_stopping("lock_torture_writer");
714 return 0;
715 }
716
717 /*
718 * Lock torture reader kthread. Repeatedly acquires and releases
719 * the reader lock.
720 */
lock_torture_reader(void * arg)721 static int lock_torture_reader(void *arg)
722 {
723 struct lock_stress_stats *lrsp = arg;
724 int tid = lrsp - cxt.lrsa;
725 DEFINE_TORTURE_RANDOM(rand);
726
727 VERBOSE_TOROUT_STRING("lock_torture_reader task started");
728 set_user_nice(current, MAX_NICE);
729
730 do {
731 if ((torture_random(&rand) & 0xfffff) == 0)
732 schedule_timeout_uninterruptible(1);
733
734 cxt.cur_ops->readlock(tid);
735 atomic_inc(&lock_is_read_held);
736 if (WARN_ON_ONCE(lock_is_write_held))
737 lrsp->n_lock_fail++; /* rare, but... */
738
739 lrsp->n_lock_acquired++;
740 cxt.cur_ops->read_delay(&rand);
741 atomic_dec(&lock_is_read_held);
742 cxt.cur_ops->readunlock(tid);
743
744 stutter_wait("lock_torture_reader");
745 } while (!torture_must_stop());
746 torture_kthread_stopping("lock_torture_reader");
747 return 0;
748 }
749
750 /*
751 * Create an lock-torture-statistics message in the specified buffer.
752 */
__torture_print_stats(char * page,struct lock_stress_stats * statp,bool write)753 static void __torture_print_stats(char *page,
754 struct lock_stress_stats *statp, bool write)
755 {
756 long cur;
757 bool fail = false;
758 int i, n_stress;
759 long max = 0, min = statp ? data_race(statp[0].n_lock_acquired) : 0;
760 long long sum = 0;
761
762 n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress;
763 for (i = 0; i < n_stress; i++) {
764 if (data_race(statp[i].n_lock_fail))
765 fail = true;
766 cur = data_race(statp[i].n_lock_acquired);
767 sum += cur;
768 if (max < cur)
769 max = cur;
770 if (min > cur)
771 min = cur;
772 }
773 page += sprintf(page,
774 "%s: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n",
775 write ? "Writes" : "Reads ",
776 sum, max, min,
777 !onoff_interval && max / 2 > min ? "???" : "",
778 fail, fail ? "!!!" : "");
779 if (fail)
780 atomic_inc(&cxt.n_lock_torture_errors);
781 }
782
783 /*
784 * Print torture statistics. Caller must ensure that there is only one
785 * call to this function at a given time!!! This is normally accomplished
786 * by relying on the module system to only have one copy of the module
787 * loaded, and then by giving the lock_torture_stats kthread full control
788 * (or the init/cleanup functions when lock_torture_stats thread is not
789 * running).
790 */
lock_torture_stats_print(void)791 static void lock_torture_stats_print(void)
792 {
793 int size = cxt.nrealwriters_stress * 200 + 8192;
794 char *buf;
795
796 if (cxt.cur_ops->readlock)
797 size += cxt.nrealreaders_stress * 200 + 8192;
798
799 buf = kmalloc(size, GFP_KERNEL);
800 if (!buf) {
801 pr_err("lock_torture_stats_print: Out of memory, need: %d",
802 size);
803 return;
804 }
805
806 __torture_print_stats(buf, cxt.lwsa, true);
807 pr_alert("%s", buf);
808 kfree(buf);
809
810 if (cxt.cur_ops->readlock) {
811 buf = kmalloc(size, GFP_KERNEL);
812 if (!buf) {
813 pr_err("lock_torture_stats_print: Out of memory, need: %d",
814 size);
815 return;
816 }
817
818 __torture_print_stats(buf, cxt.lrsa, false);
819 pr_alert("%s", buf);
820 kfree(buf);
821 }
822 }
823
824 /*
825 * Periodically prints torture statistics, if periodic statistics printing
826 * was specified via the stat_interval module parameter.
827 *
828 * No need to worry about fullstop here, since this one doesn't reference
829 * volatile state or register callbacks.
830 */
lock_torture_stats(void * arg)831 static int lock_torture_stats(void *arg)
832 {
833 VERBOSE_TOROUT_STRING("lock_torture_stats task started");
834 do {
835 schedule_timeout_interruptible(stat_interval * HZ);
836 lock_torture_stats_print();
837 torture_shutdown_absorb("lock_torture_stats");
838 } while (!torture_must_stop());
839 torture_kthread_stopping("lock_torture_stats");
840 return 0;
841 }
842
843 static inline void
lock_torture_print_module_parms(struct lock_torture_ops * cur_ops,const char * tag)844 lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
845 const char *tag)
846 {
847 pr_alert("%s" TORTURE_FLAG
848 "--- %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",
849 torture_type, tag, cxt.debug_lock ? " [debug]": "",
850 cxt.nrealwriters_stress, cxt.nrealreaders_stress, stat_interval,
851 verbose, shuffle_interval, stutter, shutdown_secs,
852 onoff_interval, onoff_holdoff);
853 }
854
lock_torture_cleanup(void)855 static void lock_torture_cleanup(void)
856 {
857 int i;
858
859 if (torture_cleanup_begin())
860 return;
861
862 /*
863 * Indicates early cleanup, meaning that the test has not run,
864 * such as when passing bogus args when loading the module.
865 * However cxt->cur_ops.init() may have been invoked, so beside
866 * perform the underlying torture-specific cleanups, cur_ops.exit()
867 * will be invoked if needed.
868 */
869 if (!cxt.lwsa && !cxt.lrsa)
870 goto end;
871
872 if (writer_tasks) {
873 for (i = 0; i < cxt.nrealwriters_stress; i++)
874 torture_stop_kthread(lock_torture_writer,
875 writer_tasks[i]);
876 kfree(writer_tasks);
877 writer_tasks = NULL;
878 }
879
880 if (reader_tasks) {
881 for (i = 0; i < cxt.nrealreaders_stress; i++)
882 torture_stop_kthread(lock_torture_reader,
883 reader_tasks[i]);
884 kfree(reader_tasks);
885 reader_tasks = NULL;
886 }
887
888 torture_stop_kthread(lock_torture_stats, stats_task);
889 lock_torture_stats_print(); /* -After- the stats thread is stopped! */
890
891 if (atomic_read(&cxt.n_lock_torture_errors))
892 lock_torture_print_module_parms(cxt.cur_ops,
893 "End of test: FAILURE");
894 else if (torture_onoff_failures())
895 lock_torture_print_module_parms(cxt.cur_ops,
896 "End of test: LOCK_HOTPLUG");
897 else
898 lock_torture_print_module_parms(cxt.cur_ops,
899 "End of test: SUCCESS");
900
901 kfree(cxt.lwsa);
902 cxt.lwsa = NULL;
903 kfree(cxt.lrsa);
904 cxt.lrsa = NULL;
905
906 end:
907 if (cxt.init_called) {
908 if (cxt.cur_ops->exit)
909 cxt.cur_ops->exit();
910 cxt.init_called = false;
911 }
912 torture_cleanup_end();
913 }
914
lock_torture_init(void)915 static int __init lock_torture_init(void)
916 {
917 int i, j;
918 int firsterr = 0;
919 static struct lock_torture_ops *torture_ops[] = {
920 &lock_busted_ops,
921 &spin_lock_ops, &spin_lock_irq_ops,
922 &rw_lock_ops, &rw_lock_irq_ops,
923 &mutex_lock_ops,
924 &ww_mutex_lock_ops,
925 #ifdef CONFIG_RT_MUTEXES
926 &rtmutex_lock_ops,
927 #endif
928 &rwsem_lock_ops,
929 &percpu_rwsem_lock_ops,
930 };
931
932 if (!torture_init_begin(torture_type, verbose))
933 return -EBUSY;
934
935 /* Process args and tell the world that the torturer is on the job. */
936 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
937 cxt.cur_ops = torture_ops[i];
938 if (strcmp(torture_type, cxt.cur_ops->name) == 0)
939 break;
940 }
941 if (i == ARRAY_SIZE(torture_ops)) {
942 pr_alert("lock-torture: invalid torture type: \"%s\"\n",
943 torture_type);
944 pr_alert("lock-torture types:");
945 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
946 pr_alert(" %s", torture_ops[i]->name);
947 pr_alert("\n");
948 firsterr = -EINVAL;
949 goto unwind;
950 }
951
952 if (nwriters_stress == 0 &&
953 (!cxt.cur_ops->readlock || nreaders_stress == 0)) {
954 pr_alert("lock-torture: must run at least one locking thread\n");
955 firsterr = -EINVAL;
956 goto unwind;
957 }
958
959 if (nwriters_stress >= 0)
960 cxt.nrealwriters_stress = nwriters_stress;
961 else
962 cxt.nrealwriters_stress = 2 * num_online_cpus();
963
964 if (cxt.cur_ops->init) {
965 cxt.cur_ops->init();
966 cxt.init_called = true;
967 }
968
969 #ifdef CONFIG_DEBUG_MUTEXES
970 if (str_has_prefix(torture_type, "mutex"))
971 cxt.debug_lock = true;
972 #endif
973 #ifdef CONFIG_DEBUG_RT_MUTEXES
974 if (str_has_prefix(torture_type, "rtmutex"))
975 cxt.debug_lock = true;
976 #endif
977 #ifdef CONFIG_DEBUG_SPINLOCK
978 if ((str_has_prefix(torture_type, "spin")) ||
979 (str_has_prefix(torture_type, "rw_lock")))
980 cxt.debug_lock = true;
981 #endif
982
983 /* Initialize the statistics so that each run gets its own numbers. */
984 if (nwriters_stress) {
985 lock_is_write_held = false;
986 cxt.lwsa = kmalloc_array(cxt.nrealwriters_stress,
987 sizeof(*cxt.lwsa),
988 GFP_KERNEL);
989 if (cxt.lwsa == NULL) {
990 VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory");
991 firsterr = -ENOMEM;
992 goto unwind;
993 }
994
995 for (i = 0; i < cxt.nrealwriters_stress; i++) {
996 cxt.lwsa[i].n_lock_fail = 0;
997 cxt.lwsa[i].n_lock_acquired = 0;
998 }
999 }
1000
1001 if (cxt.cur_ops->readlock) {
1002 if (nreaders_stress >= 0)
1003 cxt.nrealreaders_stress = nreaders_stress;
1004 else {
1005 /*
1006 * By default distribute evenly the number of
1007 * readers and writers. We still run the same number
1008 * of threads as the writer-only locks default.
1009 */
1010 if (nwriters_stress < 0) /* user doesn't care */
1011 cxt.nrealwriters_stress = num_online_cpus();
1012 cxt.nrealreaders_stress = cxt.nrealwriters_stress;
1013 }
1014
1015 if (nreaders_stress) {
1016 cxt.lrsa = kmalloc_array(cxt.nrealreaders_stress,
1017 sizeof(*cxt.lrsa),
1018 GFP_KERNEL);
1019 if (cxt.lrsa == NULL) {
1020 VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory");
1021 firsterr = -ENOMEM;
1022 kfree(cxt.lwsa);
1023 cxt.lwsa = NULL;
1024 goto unwind;
1025 }
1026
1027 for (i = 0; i < cxt.nrealreaders_stress; i++) {
1028 cxt.lrsa[i].n_lock_fail = 0;
1029 cxt.lrsa[i].n_lock_acquired = 0;
1030 }
1031 }
1032 }
1033
1034 lock_torture_print_module_parms(cxt.cur_ops, "Start of test");
1035
1036 /* Prepare torture context. */
1037 if (onoff_interval > 0) {
1038 firsterr = torture_onoff_init(onoff_holdoff * HZ,
1039 onoff_interval * HZ, NULL);
1040 if (torture_init_error(firsterr))
1041 goto unwind;
1042 }
1043 if (shuffle_interval > 0) {
1044 firsterr = torture_shuffle_init(shuffle_interval);
1045 if (torture_init_error(firsterr))
1046 goto unwind;
1047 }
1048 if (shutdown_secs > 0) {
1049 firsterr = torture_shutdown_init(shutdown_secs,
1050 lock_torture_cleanup);
1051 if (torture_init_error(firsterr))
1052 goto unwind;
1053 }
1054 if (stutter > 0) {
1055 firsterr = torture_stutter_init(stutter, stutter);
1056 if (torture_init_error(firsterr))
1057 goto unwind;
1058 }
1059
1060 if (nwriters_stress) {
1061 writer_tasks = kcalloc(cxt.nrealwriters_stress,
1062 sizeof(writer_tasks[0]),
1063 GFP_KERNEL);
1064 if (writer_tasks == NULL) {
1065 TOROUT_ERRSTRING("writer_tasks: Out of memory");
1066 firsterr = -ENOMEM;
1067 goto unwind;
1068 }
1069 }
1070
1071 if (cxt.cur_ops->readlock) {
1072 reader_tasks = kcalloc(cxt.nrealreaders_stress,
1073 sizeof(reader_tasks[0]),
1074 GFP_KERNEL);
1075 if (reader_tasks == NULL) {
1076 TOROUT_ERRSTRING("reader_tasks: Out of memory");
1077 kfree(writer_tasks);
1078 writer_tasks = NULL;
1079 firsterr = -ENOMEM;
1080 goto unwind;
1081 }
1082 }
1083
1084 /*
1085 * Create the kthreads and start torturing (oh, those poor little locks).
1086 *
1087 * TODO: Note that we interleave writers with readers, giving writers a
1088 * slight advantage, by creating its kthread first. This can be modified
1089 * for very specific needs, or even let the user choose the policy, if
1090 * ever wanted.
1091 */
1092 for (i = 0, j = 0; i < cxt.nrealwriters_stress ||
1093 j < cxt.nrealreaders_stress; i++, j++) {
1094 if (i >= cxt.nrealwriters_stress)
1095 goto create_reader;
1096
1097 /* Create writer. */
1098 firsterr = torture_create_kthread(lock_torture_writer, &cxt.lwsa[i],
1099 writer_tasks[i]);
1100 if (torture_init_error(firsterr))
1101 goto unwind;
1102
1103 create_reader:
1104 if (cxt.cur_ops->readlock == NULL || (j >= cxt.nrealreaders_stress))
1105 continue;
1106 /* Create reader. */
1107 firsterr = torture_create_kthread(lock_torture_reader, &cxt.lrsa[j],
1108 reader_tasks[j]);
1109 if (torture_init_error(firsterr))
1110 goto unwind;
1111 }
1112 if (stat_interval > 0) {
1113 firsterr = torture_create_kthread(lock_torture_stats, NULL,
1114 stats_task);
1115 if (torture_init_error(firsterr))
1116 goto unwind;
1117 }
1118 torture_init_end();
1119 return 0;
1120
1121 unwind:
1122 torture_init_end();
1123 lock_torture_cleanup();
1124 if (shutdown_secs) {
1125 WARN_ON(!IS_MODULE(CONFIG_LOCK_TORTURE_TEST));
1126 kernel_power_off();
1127 }
1128 return firsterr;
1129 }
1130
1131 module_init(lock_torture_init);
1132 module_exit(lock_torture_cleanup);
1133