2 * Module-based torture test facility for locking
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.
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.
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.
18 * Copyright (C) IBM Corporation, 2014
20 * Author: Paul E. McKenney <paulmck@us.ibm.com>
21 * Based on kernel/rcu/torture.c.
23 #include <linux/types.h>
24 #include <linux/kernel.h>
25 #include <linux/init.h>
26 #include <linux/module.h>
27 #include <linux/kthread.h>
28 #include <linux/err.h>
29 #include <linux/spinlock.h>
30 #include <linux/rwlock.h>
31 #include <linux/mutex.h>
32 #include <linux/smp.h>
33 #include <linux/interrupt.h>
34 #include <linux/sched.h>
35 #include <linux/atomic.h>
36 #include <linux/bitops.h>
37 #include <linux/completion.h>
38 #include <linux/moduleparam.h>
39 #include <linux/percpu.h>
40 #include <linux/notifier.h>
41 #include <linux/reboot.h>
42 #include <linux/freezer.h>
43 #include <linux/cpu.h>
44 #include <linux/delay.h>
45 #include <linux/stat.h>
46 #include <linux/slab.h>
47 #include <linux/trace_clock.h>
48 #include <asm/byteorder.h>
49 #include <linux/torture.h>
51 MODULE_LICENSE("GPL");
52 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
54 torture_param(int, nwriters_stress, -1,
55 "Number of write-locking stress-test threads");
56 torture_param(int, nreaders_stress, -1,
57 "Number of read-locking stress-test threads");
58 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
59 torture_param(int, onoff_interval, 0,
60 "Time between CPU hotplugs (s), 0=disable");
61 torture_param(int, shuffle_interval, 3,
62 "Number of jiffies between shuffles, 0=disable");
63 torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable.");
64 torture_param(int, stat_interval, 60,
65 "Number of seconds between stats printk()s");
66 torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
67 torture_param(bool, verbose, true,
68 "Enable verbose debugging printk()s");
70 static char *torture_type = "spin_lock";
71 module_param(torture_type, charp, 0444);
72 MODULE_PARM_DESC(torture_type,
73 "Type of lock to torture (spin_lock, spin_lock_irq, mutex_lock, ...)");
75 static struct task_struct *stats_task;
76 static struct task_struct **writer_tasks;
77 static struct task_struct **reader_tasks;
79 static bool lock_is_write_held;
80 static bool lock_is_read_held;
82 struct lock_stress_stats {
88 #define LOCKTORTURE_RUNNABLE_INIT 1
90 #define LOCKTORTURE_RUNNABLE_INIT 0
92 int torture_runnable = LOCKTORTURE_RUNNABLE_INIT;
93 module_param(torture_runnable, int, 0444);
94 MODULE_PARM_DESC(torture_runnable, "Start locktorture at module init");
96 /* Forward reference. */
97 static void lock_torture_cleanup(void);
100 * Operations vector for selecting different types of tests.
102 struct lock_torture_ops {
104 int (*writelock)(void);
105 void (*write_delay)(struct torture_random_state *trsp);
106 void (*writeunlock)(void);
107 int (*readlock)(void);
108 void (*read_delay)(struct torture_random_state *trsp);
109 void (*readunlock)(void);
114 struct lock_torture_cxt {
115 int nrealwriters_stress;
116 int nrealreaders_stress;
118 atomic_t n_lock_torture_errors;
119 struct lock_torture_ops *cur_ops;
120 struct lock_stress_stats *lwsa; /* writer statistics */
121 struct lock_stress_stats *lrsa; /* reader statistics */
123 static struct lock_torture_cxt cxt = { 0, 0, false,
127 * Definitions for lock torture testing.
130 static int torture_lock_busted_write_lock(void)
132 return 0; /* BUGGY, do not use in real life!!! */
135 static void torture_lock_busted_write_delay(struct torture_random_state *trsp)
137 const unsigned long longdelay_us = 100;
139 /* We want a long delay occasionally to force massive contention. */
140 if (!(torture_random(trsp) %
141 (cxt.nrealwriters_stress * 2000 * longdelay_us)))
142 mdelay(longdelay_us);
143 #ifdef CONFIG_PREEMPT
144 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
145 preempt_schedule(); /* Allow test to be preempted. */
149 static void torture_lock_busted_write_unlock(void)
151 /* BUGGY, do not use in real life!!! */
154 static struct lock_torture_ops lock_busted_ops = {
155 .writelock = torture_lock_busted_write_lock,
156 .write_delay = torture_lock_busted_write_delay,
157 .writeunlock = torture_lock_busted_write_unlock,
161 .name = "lock_busted"
164 static DEFINE_SPINLOCK(torture_spinlock);
166 static int torture_spin_lock_write_lock(void) __acquires(torture_spinlock)
168 spin_lock(&torture_spinlock);
172 static void torture_spin_lock_write_delay(struct torture_random_state *trsp)
174 const unsigned long shortdelay_us = 2;
175 const unsigned long longdelay_us = 100;
177 /* We want a short delay mostly to emulate likely code, and
178 * we want a long delay occasionally to force massive contention.
180 if (!(torture_random(trsp) %
181 (cxt.nrealwriters_stress * 2000 * longdelay_us)))
182 mdelay(longdelay_us);
183 if (!(torture_random(trsp) %
184 (cxt.nrealwriters_stress * 2 * shortdelay_us)))
185 udelay(shortdelay_us);
186 #ifdef CONFIG_PREEMPT
187 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
188 preempt_schedule(); /* Allow test to be preempted. */
192 static void torture_spin_lock_write_unlock(void) __releases(torture_spinlock)
194 spin_unlock(&torture_spinlock);
197 static struct lock_torture_ops spin_lock_ops = {
198 .writelock = torture_spin_lock_write_lock,
199 .write_delay = torture_spin_lock_write_delay,
200 .writeunlock = torture_spin_lock_write_unlock,
207 static int torture_spin_lock_write_lock_irq(void)
208 __acquires(torture_spinlock_irq)
212 spin_lock_irqsave(&torture_spinlock, flags);
213 cxt.cur_ops->flags = flags;
217 static void torture_lock_spin_write_unlock_irq(void)
218 __releases(torture_spinlock)
220 spin_unlock_irqrestore(&torture_spinlock, cxt.cur_ops->flags);
223 static struct lock_torture_ops spin_lock_irq_ops = {
224 .writelock = torture_spin_lock_write_lock_irq,
225 .write_delay = torture_spin_lock_write_delay,
226 .writeunlock = torture_lock_spin_write_unlock_irq,
230 .name = "spin_lock_irq"
233 static DEFINE_RWLOCK(torture_rwlock);
235 static int torture_rwlock_write_lock(void) __acquires(torture_rwlock)
237 write_lock(&torture_rwlock);
241 static void torture_rwlock_write_delay(struct torture_random_state *trsp)
243 const unsigned long shortdelay_us = 2;
244 const unsigned long longdelay_ms = 100;
246 /* We want a short delay mostly to emulate likely code, and
247 * we want a long delay occasionally to force massive contention.
249 if (!(torture_random(trsp) %
250 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
251 mdelay(longdelay_ms);
253 udelay(shortdelay_us);
256 static void torture_rwlock_write_unlock(void) __releases(torture_rwlock)
258 write_unlock(&torture_rwlock);
261 static int torture_rwlock_read_lock(void) __acquires(torture_rwlock)
263 read_lock(&torture_rwlock);
267 static void torture_rwlock_read_delay(struct torture_random_state *trsp)
269 const unsigned long shortdelay_us = 10;
270 const unsigned long longdelay_ms = 100;
272 /* We want a short delay mostly to emulate likely code, and
273 * we want a long delay occasionally to force massive contention.
275 if (!(torture_random(trsp) %
276 (cxt.nrealreaders_stress * 2000 * longdelay_ms)))
277 mdelay(longdelay_ms);
279 udelay(shortdelay_us);
282 static void torture_rwlock_read_unlock(void) __releases(torture_rwlock)
284 read_unlock(&torture_rwlock);
287 static struct lock_torture_ops rw_lock_ops = {
288 .writelock = torture_rwlock_write_lock,
289 .write_delay = torture_rwlock_write_delay,
290 .writeunlock = torture_rwlock_write_unlock,
291 .readlock = torture_rwlock_read_lock,
292 .read_delay = torture_rwlock_read_delay,
293 .readunlock = torture_rwlock_read_unlock,
297 static int torture_rwlock_write_lock_irq(void) __acquires(torture_rwlock)
301 write_lock_irqsave(&torture_rwlock, flags);
302 cxt.cur_ops->flags = flags;
306 static void torture_rwlock_write_unlock_irq(void)
307 __releases(torture_rwlock)
309 write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
312 static int torture_rwlock_read_lock_irq(void) __acquires(torture_rwlock)
316 read_lock_irqsave(&torture_rwlock, flags);
317 cxt.cur_ops->flags = flags;
321 static void torture_rwlock_read_unlock_irq(void)
322 __releases(torture_rwlock)
324 write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
327 static struct lock_torture_ops rw_lock_irq_ops = {
328 .writelock = torture_rwlock_write_lock_irq,
329 .write_delay = torture_rwlock_write_delay,
330 .writeunlock = torture_rwlock_write_unlock_irq,
331 .readlock = torture_rwlock_read_lock_irq,
332 .read_delay = torture_rwlock_read_delay,
333 .readunlock = torture_rwlock_read_unlock_irq,
334 .name = "rw_lock_irq"
337 static DEFINE_MUTEX(torture_mutex);
339 static int torture_mutex_lock(void) __acquires(torture_mutex)
341 mutex_lock(&torture_mutex);
345 static void torture_mutex_delay(struct torture_random_state *trsp)
347 const unsigned long longdelay_ms = 100;
349 /* We want a long delay occasionally to force massive contention. */
350 if (!(torture_random(trsp) %
351 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
352 mdelay(longdelay_ms * 5);
354 mdelay(longdelay_ms / 5);
355 #ifdef CONFIG_PREEMPT
356 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
357 preempt_schedule(); /* Allow test to be preempted. */
361 static void torture_mutex_unlock(void) __releases(torture_mutex)
363 mutex_unlock(&torture_mutex);
366 static struct lock_torture_ops mutex_lock_ops = {
367 .writelock = torture_mutex_lock,
368 .write_delay = torture_mutex_delay,
369 .writeunlock = torture_mutex_unlock,
376 static DECLARE_RWSEM(torture_rwsem);
377 static int torture_rwsem_down_write(void) __acquires(torture_rwsem)
379 down_write(&torture_rwsem);
383 static void torture_rwsem_write_delay(struct torture_random_state *trsp)
385 const unsigned long longdelay_ms = 100;
387 /* We want a long delay occasionally to force massive contention. */
388 if (!(torture_random(trsp) %
389 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
390 mdelay(longdelay_ms * 10);
392 mdelay(longdelay_ms / 10);
393 #ifdef CONFIG_PREEMPT
394 if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
395 preempt_schedule(); /* Allow test to be preempted. */
399 static void torture_rwsem_up_write(void) __releases(torture_rwsem)
401 up_write(&torture_rwsem);
404 static int torture_rwsem_down_read(void) __acquires(torture_rwsem)
406 down_read(&torture_rwsem);
410 static void torture_rwsem_read_delay(struct torture_random_state *trsp)
412 const unsigned long longdelay_ms = 100;
414 /* We want a long delay occasionally to force massive contention. */
415 if (!(torture_random(trsp) %
416 (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
417 mdelay(longdelay_ms * 2);
419 mdelay(longdelay_ms / 2);
420 #ifdef CONFIG_PREEMPT
421 if (!(torture_random(trsp) % (cxt.nrealreaders_stress * 20000)))
422 preempt_schedule(); /* Allow test to be preempted. */
426 static void torture_rwsem_up_read(void) __releases(torture_rwsem)
428 up_read(&torture_rwsem);
431 static struct lock_torture_ops rwsem_lock_ops = {
432 .writelock = torture_rwsem_down_write,
433 .write_delay = torture_rwsem_write_delay,
434 .writeunlock = torture_rwsem_up_write,
435 .readlock = torture_rwsem_down_read,
436 .read_delay = torture_rwsem_read_delay,
437 .readunlock = torture_rwsem_up_read,
442 * Lock torture writer kthread. Repeatedly acquires and releases
443 * the lock, checking for duplicate acquisitions.
445 static int lock_torture_writer(void *arg)
447 struct lock_stress_stats *lwsp = arg;
448 static DEFINE_TORTURE_RANDOM(rand);
450 VERBOSE_TOROUT_STRING("lock_torture_writer task started");
451 set_user_nice(current, MAX_NICE);
454 if ((torture_random(&rand) & 0xfffff) == 0)
455 schedule_timeout_uninterruptible(1);
456 cxt.cur_ops->writelock();
457 if (WARN_ON_ONCE(lock_is_write_held))
459 lock_is_write_held = 1;
460 lwsp->n_lock_acquired++;
461 cxt.cur_ops->write_delay(&rand);
462 lock_is_write_held = 0;
463 cxt.cur_ops->writeunlock();
464 stutter_wait("lock_torture_writer");
465 } while (!torture_must_stop());
466 torture_kthread_stopping("lock_torture_writer");
471 * Lock torture reader kthread. Repeatedly acquires and releases
474 static int lock_torture_reader(void *arg)
476 struct lock_stress_stats *lrsp = arg;
477 static DEFINE_TORTURE_RANDOM(rand);
479 VERBOSE_TOROUT_STRING("lock_torture_reader task started");
480 set_user_nice(current, MAX_NICE);
483 if ((torture_random(&rand) & 0xfffff) == 0)
484 schedule_timeout_uninterruptible(1);
485 cxt.cur_ops->readlock();
486 lock_is_read_held = 1;
487 lrsp->n_lock_acquired++;
488 cxt.cur_ops->read_delay(&rand);
489 lock_is_read_held = 0;
490 cxt.cur_ops->readunlock();
491 stutter_wait("lock_torture_reader");
492 } while (!torture_must_stop());
493 torture_kthread_stopping("lock_torture_reader");
498 * Create an lock-torture-statistics message in the specified buffer.
500 static void __torture_print_stats(char *page,
501 struct lock_stress_stats *statp, bool write)
506 long min = statp[0].n_lock_acquired;
509 n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress;
510 for (i = 0; i < n_stress; i++) {
511 if (statp[i].n_lock_fail)
513 sum += statp[i].n_lock_acquired;
514 if (max < statp[i].n_lock_fail)
515 max = statp[i].n_lock_fail;
516 if (min > statp[i].n_lock_fail)
517 min = statp[i].n_lock_fail;
519 page += sprintf(page,
520 "%s: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n",
521 write ? "Writes" : "Reads ",
522 sum, max, min, max / 2 > min ? "???" : "",
523 fail, fail ? "!!!" : "");
525 atomic_inc(&cxt.n_lock_torture_errors);
529 * Print torture statistics. Caller must ensure that there is only one
530 * call to this function at a given time!!! This is normally accomplished
531 * by relying on the module system to only have one copy of the module
532 * loaded, and then by giving the lock_torture_stats kthread full control
533 * (or the init/cleanup functions when lock_torture_stats thread is not
536 static void lock_torture_stats_print(void)
538 int size = cxt.nrealwriters_stress * 200 + 8192;
541 if (cxt.cur_ops->readlock)
542 size += cxt.nrealreaders_stress * 200 + 8192;
544 buf = kmalloc(size, GFP_KERNEL);
546 pr_err("lock_torture_stats_print: Out of memory, need: %d",
551 __torture_print_stats(buf, cxt.lwsa, true);
555 if (cxt.cur_ops->readlock) {
556 buf = kmalloc(size, GFP_KERNEL);
558 pr_err("lock_torture_stats_print: Out of memory, need: %d",
563 __torture_print_stats(buf, cxt.lrsa, false);
570 * Periodically prints torture statistics, if periodic statistics printing
571 * was specified via the stat_interval module parameter.
573 * No need to worry about fullstop here, since this one doesn't reference
574 * volatile state or register callbacks.
576 static int lock_torture_stats(void *arg)
578 VERBOSE_TOROUT_STRING("lock_torture_stats task started");
580 schedule_timeout_interruptible(stat_interval * HZ);
581 lock_torture_stats_print();
582 torture_shutdown_absorb("lock_torture_stats");
583 } while (!torture_must_stop());
584 torture_kthread_stopping("lock_torture_stats");
589 lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
592 pr_alert("%s" TORTURE_FLAG
593 "--- %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",
594 torture_type, tag, cxt.debug_lock ? " [debug]": "",
595 cxt.nrealwriters_stress, cxt.nrealreaders_stress, stat_interval,
596 verbose, shuffle_interval, stutter, shutdown_secs,
597 onoff_interval, onoff_holdoff);
600 static void lock_torture_cleanup(void)
604 if (torture_cleanup_begin())
608 for (i = 0; i < cxt.nrealwriters_stress; i++)
609 torture_stop_kthread(lock_torture_writer,
616 for (i = 0; i < cxt.nrealreaders_stress; i++)
617 torture_stop_kthread(lock_torture_reader,
623 torture_stop_kthread(lock_torture_stats, stats_task);
624 lock_torture_stats_print(); /* -After- the stats thread is stopped! */
626 if (atomic_read(&cxt.n_lock_torture_errors))
627 lock_torture_print_module_parms(cxt.cur_ops,
628 "End of test: FAILURE");
629 else if (torture_onoff_failures())
630 lock_torture_print_module_parms(cxt.cur_ops,
631 "End of test: LOCK_HOTPLUG");
633 lock_torture_print_module_parms(cxt.cur_ops,
634 "End of test: SUCCESS");
635 torture_cleanup_end();
638 static int __init lock_torture_init(void)
642 static struct lock_torture_ops *torture_ops[] = {
644 &spin_lock_ops, &spin_lock_irq_ops,
645 &rw_lock_ops, &rw_lock_irq_ops,
650 if (!torture_init_begin(torture_type, verbose, &torture_runnable))
653 /* Process args and tell the world that the torturer is on the job. */
654 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
655 cxt.cur_ops = torture_ops[i];
656 if (strcmp(torture_type, cxt.cur_ops->name) == 0)
659 if (i == ARRAY_SIZE(torture_ops)) {
660 pr_alert("lock-torture: invalid torture type: \"%s\"\n",
662 pr_alert("lock-torture types:");
663 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
664 pr_alert(" %s", torture_ops[i]->name);
669 if (cxt.cur_ops->init)
670 cxt.cur_ops->init(); /* no "goto unwind" prior to this point!!! */
672 if (nwriters_stress >= 0)
673 cxt.nrealwriters_stress = nwriters_stress;
675 cxt.nrealwriters_stress = 2 * num_online_cpus();
677 #ifdef CONFIG_DEBUG_MUTEXES
678 if (strncmp(torture_type, "mutex", 5) == 0)
679 cxt.debug_lock = true;
681 #ifdef CONFIG_DEBUG_SPINLOCK
682 if ((strncmp(torture_type, "spin", 4) == 0) ||
683 (strncmp(torture_type, "rw_lock", 7) == 0))
684 cxt.debug_lock = true;
687 /* Initialize the statistics so that each run gets its own numbers. */
689 lock_is_write_held = 0;
690 cxt.lwsa = kmalloc(sizeof(*cxt.lwsa) * cxt.nrealwriters_stress, GFP_KERNEL);
691 if (cxt.lwsa == NULL) {
692 VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory");
696 for (i = 0; i < cxt.nrealwriters_stress; i++) {
697 cxt.lwsa[i].n_lock_fail = 0;
698 cxt.lwsa[i].n_lock_acquired = 0;
701 if (cxt.cur_ops->readlock) {
702 if (nreaders_stress >= 0)
703 cxt.nrealreaders_stress = nreaders_stress;
706 * By default distribute evenly the number of
707 * readers and writers. We still run the same number
708 * of threads as the writer-only locks default.
710 if (nwriters_stress < 0) /* user doesn't care */
711 cxt.nrealwriters_stress = num_online_cpus();
712 cxt.nrealreaders_stress = cxt.nrealwriters_stress;
715 lock_is_read_held = 0;
716 cxt.lrsa = kmalloc(sizeof(*cxt.lrsa) * cxt.nrealreaders_stress, GFP_KERNEL);
717 if (cxt.lrsa == NULL) {
718 VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory");
724 for (i = 0; i < cxt.nrealreaders_stress; i++) {
725 cxt.lrsa[i].n_lock_fail = 0;
726 cxt.lrsa[i].n_lock_acquired = 0;
729 lock_torture_print_module_parms(cxt.cur_ops, "Start of test");
731 /* Prepare torture context. */
732 if (onoff_interval > 0) {
733 firsterr = torture_onoff_init(onoff_holdoff * HZ,
734 onoff_interval * HZ);
738 if (shuffle_interval > 0) {
739 firsterr = torture_shuffle_init(shuffle_interval);
743 if (shutdown_secs > 0) {
744 firsterr = torture_shutdown_init(shutdown_secs,
745 lock_torture_cleanup);
750 firsterr = torture_stutter_init(stutter);
755 writer_tasks = kzalloc(cxt.nrealwriters_stress * sizeof(writer_tasks[0]),
757 if (writer_tasks == NULL) {
758 VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory");
763 if (cxt.cur_ops->readlock) {
764 reader_tasks = kzalloc(cxt.nrealreaders_stress * sizeof(reader_tasks[0]),
766 if (reader_tasks == NULL) {
767 VERBOSE_TOROUT_ERRSTRING("reader_tasks: Out of memory");
774 * Create the kthreads and start torturing (oh, those poor little locks).
776 * TODO: Note that we interleave writers with readers, giving writers a
777 * slight advantage, by creating its kthread first. This can be modified
778 * for very specific needs, or even let the user choose the policy, if
781 for (i = 0, j = 0; i < cxt.nrealwriters_stress ||
782 j < cxt.nrealreaders_stress; i++, j++) {
783 if (i >= cxt.nrealwriters_stress)
787 firsterr = torture_create_kthread(lock_torture_writer, &cxt.lwsa[i],
793 if (cxt.cur_ops->readlock == NULL || (j >= cxt.nrealreaders_stress))
796 firsterr = torture_create_kthread(lock_torture_reader, &cxt.lrsa[j],
801 if (stat_interval > 0) {
802 firsterr = torture_create_kthread(lock_torture_stats, NULL,
812 lock_torture_cleanup();
816 module_init(lock_torture_init);
817 module_exit(lock_torture_cleanup);