1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Common functions for in-kernel torture tests.
4 *
5 * Copyright (C) IBM Corporation, 2014
6 *
7 * Author: Paul E. McKenney <paulmck@linux.ibm.com>
8 * Based on kernel/rcu/torture.c.
9 */
10
11#define pr_fmt(fmt) fmt
12
13#include <linux/types.h>
14#include <linux/kernel.h>
15#include <linux/init.h>
16#include <linux/module.h>
17#include <linux/kthread.h>
18#include <linux/err.h>
19#include <linux/spinlock.h>
20#include <linux/smp.h>
21#include <linux/interrupt.h>
22#include <linux/sched.h>
23#include <linux/sched/clock.h>
24#include <linux/atomic.h>
25#include <linux/bitops.h>
26#include <linux/completion.h>
27#include <linux/moduleparam.h>
28#include <linux/percpu.h>
29#include <linux/notifier.h>
30#include <linux/reboot.h>
31#include <linux/freezer.h>
32#include <linux/cpu.h>
33#include <linux/delay.h>
34#include <linux/stat.h>
35#include <linux/slab.h>
36#include <linux/trace_clock.h>
37#include <linux/ktime.h>
38#include <asm/byteorder.h>
39#include <linux/torture.h>
40#include "rcu/rcu.h"
41
42MODULE_LICENSE("GPL");
43MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>");
44
45static char *torture_type;
46static int verbose;
47
48/* Mediate rmmod and system shutdown. Concurrent rmmod & shutdown illegal! */
49#define FULLSTOP_DONTSTOP 0 /* Normal operation. */
50#define FULLSTOP_SHUTDOWN 1 /* System shutdown with torture running. */
51#define FULLSTOP_RMMOD 2 /* Normal rmmod of torture. */
52static int fullstop = FULLSTOP_RMMOD;
53static DEFINE_MUTEX(fullstop_mutex);
54
55#ifdef CONFIG_HOTPLUG_CPU
56
57/*
58 * Variables for online-offline handling. Only present if CPU hotplug
59 * is enabled, otherwise does nothing.
60 */
61
62static struct task_struct *onoff_task;
63static long onoff_holdoff;
64static long onoff_interval;
65static torture_ofl_func *onoff_f;
66static long n_offline_attempts;
67static long n_offline_successes;
68static unsigned long sum_offline;
69static int min_offline = -1;
70static int max_offline;
71static long n_online_attempts;
72static long n_online_successes;
73static unsigned long sum_online;
74static int min_online = -1;
75static int max_online;
76
77/*
78 * Attempt to take a CPU offline. Return false if the CPU is already
79 * offline or if it is not subject to CPU-hotplug operations. The
80 * caller can detect other failures by looking at the statistics.
81 */
82bool torture_offline(int cpu, long *n_offl_attempts, long *n_offl_successes,
83 unsigned long *sum_offl, int *min_offl, int *max_offl)
84{
85 unsigned long delta;
86 int ret;
87 unsigned long starttime;
88
89 if (!cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
90 return false;
91
92 if (verbose > 1)
93 pr_alert("%s" TORTURE_FLAG
94 "torture_onoff task: offlining %d\n",
95 torture_type, cpu);
96 starttime = jiffies;
97 (*n_offl_attempts)++;
98 ret = cpu_down(cpu);
99 if (ret) {
100 if (verbose)
101 pr_alert("%s" TORTURE_FLAG
102 "torture_onoff task: offline %d failed: errno %d\n",
103 torture_type, cpu, ret);
104 } else {
105 if (verbose > 1)
106 pr_alert("%s" TORTURE_FLAG
107 "torture_onoff task: offlined %d\n",
108 torture_type, cpu);
109 if (onoff_f)
110 onoff_f();
111 (*n_offl_successes)++;
112 delta = jiffies - starttime;
113 *sum_offl += delta;
114 if (*min_offl < 0) {
115 *min_offl = delta;
116 *max_offl = delta;
117 }
118 if (*min_offl > delta)
119 *min_offl = delta;
120 if (*max_offl < delta)
121 *max_offl = delta;
122 }
123
124 return true;
125}
126EXPORT_SYMBOL_GPL(torture_offline);
127
128/*
129 * Attempt to bring a CPU online. Return false if the CPU is already
130 * online or if it is not subject to CPU-hotplug operations. The
131 * caller can detect other failures by looking at the statistics.
132 */
133bool torture_online(int cpu, long *n_onl_attempts, long *n_onl_successes,
134 unsigned long *sum_onl, int *min_onl, int *max_onl)
135{
136 unsigned long delta;
137 int ret;
138 unsigned long starttime;
139
140 if (cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
141 return false;
142
143 if (verbose > 1)
144 pr_alert("%s" TORTURE_FLAG
145 "torture_onoff task: onlining %d\n",
146 torture_type, cpu);
147 starttime = jiffies;
148 (*n_onl_attempts)++;
149 ret = cpu_up(cpu);
150 if (ret) {
151 if (verbose)
152 pr_alert("%s" TORTURE_FLAG
153 "torture_onoff task: online %d failed: errno %d\n",
154 torture_type, cpu, ret);
155 } else {
156 if (verbose > 1)
157 pr_alert("%s" TORTURE_FLAG
158 "torture_onoff task: onlined %d\n",
159 torture_type, cpu);
160 (*n_onl_successes)++;
161 delta = jiffies - starttime;
162 *sum_onl += delta;
163 if (*min_onl < 0) {
164 *min_onl = delta;
165 *max_onl = delta;
166 }
167 if (*min_onl > delta)
168 *min_onl = delta;
169 if (*max_onl < delta)
170 *max_onl = delta;
171 }
172
173 return true;
174}
175EXPORT_SYMBOL_GPL(torture_online);
176
177/*
178 * Execute random CPU-hotplug operations at the interval specified
179 * by the onoff_interval.
180 */
181static int
182torture_onoff(void *arg)
183{
184 int cpu;
185 int maxcpu = -1;
186 DEFINE_TORTURE_RANDOM(rand);
187 int ret;
188
189 VERBOSE_TOROUT_STRING("torture_onoff task started");
190 for_each_online_cpu(cpu)
191 maxcpu = cpu;
192 WARN_ON(maxcpu < 0);
193 if (!IS_MODULE(CONFIG_TORTURE_TEST))
194 for_each_possible_cpu(cpu) {
195 if (cpu_online(cpu))
196 continue;
197 ret = cpu_up(cpu);
198 if (ret && verbose) {
199 pr_alert("%s" TORTURE_FLAG
200 "%s: Initial online %d: errno %d\n",
201 __func__, torture_type, cpu, ret);
202 }
203 }
204
205 if (maxcpu == 0) {
206 VERBOSE_TOROUT_STRING("Only one CPU, so CPU-hotplug testing is disabled");
207 goto stop;
208 }
209
210 if (onoff_holdoff > 0) {
211 VERBOSE_TOROUT_STRING("torture_onoff begin holdoff");
212 schedule_timeout_interruptible(onoff_holdoff);
213 VERBOSE_TOROUT_STRING("torture_onoff end holdoff");
214 }
215 while (!torture_must_stop()) {
216 cpu = (torture_random(&rand) >> 4) % (maxcpu + 1);
217 if (!torture_offline(cpu,
218 &n_offline_attempts, &n_offline_successes,
219 &sum_offline, &min_offline, &max_offline))
220 torture_online(cpu,
221 &n_online_attempts, &n_online_successes,
222 &sum_online, &min_online, &max_online);
223 schedule_timeout_interruptible(onoff_interval);
224 }
225
226stop:
227 torture_kthread_stopping("torture_onoff");
228 return 0;
229}
230
231#endif /* #ifdef CONFIG_HOTPLUG_CPU */
232
233/*
234 * Initiate online-offline handling.
235 */
236int torture_onoff_init(long ooholdoff, long oointerval, torture_ofl_func *f)
237{
238#ifdef CONFIG_HOTPLUG_CPU
239 onoff_holdoff = ooholdoff;
240 onoff_interval = oointerval;
241 onoff_f = f;
242 if (onoff_interval <= 0)
243 return 0;
244 return torture_create_kthread(torture_onoff, NULL, onoff_task);
245#else /* #ifdef CONFIG_HOTPLUG_CPU */
246 return 0;
247#endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
248}
249EXPORT_SYMBOL_GPL(torture_onoff_init);
250
251/*
252 * Clean up after online/offline testing.
253 */
254static void torture_onoff_cleanup(void)
255{
256#ifdef CONFIG_HOTPLUG_CPU
257 if (onoff_task == NULL)
258 return;
259 VERBOSE_TOROUT_STRING("Stopping torture_onoff task");
260 kthread_stop(onoff_task);
261 onoff_task = NULL;
262#endif /* #ifdef CONFIG_HOTPLUG_CPU */
263}
264EXPORT_SYMBOL_GPL(torture_onoff_cleanup);
265
266/*
267 * Print online/offline testing statistics.
268 */
269void torture_onoff_stats(void)
270{
271#ifdef CONFIG_HOTPLUG_CPU
272 pr_cont("onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ",
273 n_online_successes, n_online_attempts,
274 n_offline_successes, n_offline_attempts,
275 min_online, max_online,
276 min_offline, max_offline,
277 sum_online, sum_offline, HZ);
278#endif /* #ifdef CONFIG_HOTPLUG_CPU */
279}
280EXPORT_SYMBOL_GPL(torture_onoff_stats);
281
282/*
283 * Were all the online/offline operations successful?
284 */
285bool torture_onoff_failures(void)
286{
287#ifdef CONFIG_HOTPLUG_CPU
288 return n_online_successes != n_online_attempts ||
289 n_offline_successes != n_offline_attempts;
290#else /* #ifdef CONFIG_HOTPLUG_CPU */
291 return false;
292#endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
293}
294EXPORT_SYMBOL_GPL(torture_onoff_failures);
295
296#define TORTURE_RANDOM_MULT 39916801 /* prime */
297#define TORTURE_RANDOM_ADD 479001701 /* prime */
298#define TORTURE_RANDOM_REFRESH 10000
299
300/*
301 * Crude but fast random-number generator. Uses a linear congruential
302 * generator, with occasional help from cpu_clock().
303 */
304unsigned long
305torture_random(struct torture_random_state *trsp)
306{
307 if (--trsp->trs_count < 0) {
308 trsp->trs_state += (unsigned long)local_clock();
309 trsp->trs_count = TORTURE_RANDOM_REFRESH;
310 }
311 trsp->trs_state = trsp->trs_state * TORTURE_RANDOM_MULT +
312 TORTURE_RANDOM_ADD;
313 return swahw32(trsp->trs_state);
314}
315EXPORT_SYMBOL_GPL(torture_random);
316
317/*
318 * Variables for shuffling. The idea is to ensure that each CPU stays
319 * idle for an extended period to test interactions with dyntick idle,
320 * as well as interactions with any per-CPU variables.
321 */
322struct shuffle_task {
323 struct list_head st_l;
324 struct task_struct *st_t;
325};
326
327static long shuffle_interval; /* In jiffies. */
328static struct task_struct *shuffler_task;
329static cpumask_var_t shuffle_tmp_mask;
330static int shuffle_idle_cpu; /* Force all torture tasks off this CPU */
331static struct list_head shuffle_task_list = LIST_HEAD_INIT(shuffle_task_list);
332static DEFINE_MUTEX(shuffle_task_mutex);
333
334/*
335 * Register a task to be shuffled. If there is no memory, just splat
336 * and don't bother registering.
337 */
338void torture_shuffle_task_register(struct task_struct *tp)
339{
340 struct shuffle_task *stp;
341
342 if (WARN_ON_ONCE(tp == NULL))
343 return;
344 stp = kmalloc(sizeof(*stp), GFP_KERNEL);
345 if (WARN_ON_ONCE(stp == NULL))
346 return;
347 stp->st_t = tp;
348 mutex_lock(&shuffle_task_mutex);
349 list_add(&stp->st_l, &shuffle_task_list);
350 mutex_unlock(&shuffle_task_mutex);
351}
352EXPORT_SYMBOL_GPL(torture_shuffle_task_register);
353
354/*
355 * Unregister all tasks, for example, at the end of the torture run.
356 */
357static void torture_shuffle_task_unregister_all(void)
358{
359 struct shuffle_task *stp;
360 struct shuffle_task *p;
361
362 mutex_lock(&shuffle_task_mutex);
363 list_for_each_entry_safe(stp, p, &shuffle_task_list, st_l) {
364 list_del(&stp->st_l);
365 kfree(stp);
366 }
367 mutex_unlock(&shuffle_task_mutex);
368}
369
370/* Shuffle tasks such that we allow shuffle_idle_cpu to become idle.
371 * A special case is when shuffle_idle_cpu = -1, in which case we allow
372 * the tasks to run on all CPUs.
373 */
374static void torture_shuffle_tasks(void)
375{
376 struct shuffle_task *stp;
377
378 cpumask_setall(shuffle_tmp_mask);
379 get_online_cpus();
380
381 /* No point in shuffling if there is only one online CPU (ex: UP) */
382 if (num_online_cpus() == 1) {
383 put_online_cpus();
384 return;
385 }
386
387 /* Advance to the next CPU. Upon overflow, don't idle any CPUs. */
388 shuffle_idle_cpu = cpumask_next(shuffle_idle_cpu, shuffle_tmp_mask);
389 if (shuffle_idle_cpu >= nr_cpu_ids)
390 shuffle_idle_cpu = -1;
391 else
392 cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask);
393
394 mutex_lock(&shuffle_task_mutex);
395 list_for_each_entry(stp, &shuffle_task_list, st_l)
396 set_cpus_allowed_ptr(stp->st_t, shuffle_tmp_mask);
397 mutex_unlock(&shuffle_task_mutex);
398
399 put_online_cpus();
400}
401
402/* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
403 * system to become idle at a time and cut off its timer ticks. This is meant
404 * to test the support for such tickless idle CPU in RCU.
405 */
406static int torture_shuffle(void *arg)
407{
408 VERBOSE_TOROUT_STRING("torture_shuffle task started");
409 do {
410 schedule_timeout_interruptible(shuffle_interval);
411 torture_shuffle_tasks();
412 torture_shutdown_absorb("torture_shuffle");
413 } while (!torture_must_stop());
414 torture_kthread_stopping("torture_shuffle");
415 return 0;
416}
417
418/*
419 * Start the shuffler, with shuffint in jiffies.
420 */
421int torture_shuffle_init(long shuffint)
422{
423 shuffle_interval = shuffint;
424
425 shuffle_idle_cpu = -1;
426
427 if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
428 VERBOSE_TOROUT_ERRSTRING("Failed to alloc mask");
429 return -ENOMEM;
430 }
431
432 /* Create the shuffler thread */
433 return torture_create_kthread(torture_shuffle, NULL, shuffler_task);
434}
435EXPORT_SYMBOL_GPL(torture_shuffle_init);
436
437/*
438 * Stop the shuffling.
439 */
440static void torture_shuffle_cleanup(void)
441{
442 torture_shuffle_task_unregister_all();
443 if (shuffler_task) {
444 VERBOSE_TOROUT_STRING("Stopping torture_shuffle task");
445 kthread_stop(shuffler_task);
446 free_cpumask_var(shuffle_tmp_mask);
447 }
448 shuffler_task = NULL;
449}
450EXPORT_SYMBOL_GPL(torture_shuffle_cleanup);
451
452/*
453 * Variables for auto-shutdown. This allows "lights out" torture runs
454 * to be fully scripted.
455 */
456static struct task_struct *shutdown_task;
457static ktime_t shutdown_time; /* time to system shutdown. */
458static void (*torture_shutdown_hook)(void);
459
460/*
461 * Absorb kthreads into a kernel function that won't return, so that
462 * they won't ever access module text or data again.
463 */
464void torture_shutdown_absorb(const char *title)
465{
466 while (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
467 pr_notice("torture thread %s parking due to system shutdown\n",
468 title);
469 schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
470 }
471}
472EXPORT_SYMBOL_GPL(torture_shutdown_absorb);
473
474/*
475 * Cause the torture test to shutdown the system after the test has
476 * run for the time specified by the shutdown_secs parameter.
477 */
478static int torture_shutdown(void *arg)
479{
480 ktime_t ktime_snap;
481
482 VERBOSE_TOROUT_STRING("torture_shutdown task started");
483 ktime_snap = ktime_get();
484 while (ktime_before(ktime_snap, shutdown_time) &&
485 !torture_must_stop()) {
486 if (verbose)
487 pr_alert("%s" TORTURE_FLAG
488 "torture_shutdown task: %llu ms remaining\n",
489 torture_type,
490 ktime_ms_delta(shutdown_time, ktime_snap));
491 set_current_state(TASK_INTERRUPTIBLE);
492 schedule_hrtimeout(&shutdown_time, HRTIMER_MODE_ABS);
493 ktime_snap = ktime_get();
494 }
495 if (torture_must_stop()) {
496 torture_kthread_stopping("torture_shutdown");
497 return 0;
498 }
499
500 /* OK, shut down the system. */
501
502 VERBOSE_TOROUT_STRING("torture_shutdown task shutting down system");
503 shutdown_task = NULL; /* Avoid self-kill deadlock. */
504 if (torture_shutdown_hook)
505 torture_shutdown_hook();
506 else
507 VERBOSE_TOROUT_STRING("No torture_shutdown_hook(), skipping.");
508 rcu_ftrace_dump(DUMP_ALL);
509 kernel_power_off(); /* Shut down the system. */
510 return 0;
511}
512
513/*
514 * Start up the shutdown task.
515 */
516int torture_shutdown_init(int ssecs, void (*cleanup)(void))
517{
518 torture_shutdown_hook = cleanup;
519 if (ssecs > 0) {
520 shutdown_time = ktime_add(ktime_get(), ktime_set(ssecs, 0));
521 return torture_create_kthread(torture_shutdown, NULL,
522 shutdown_task);
523 }
524 return 0;
525}
526EXPORT_SYMBOL_GPL(torture_shutdown_init);
527
528/*
529 * Detect and respond to a system shutdown.
530 */
531static int torture_shutdown_notify(struct notifier_block *unused1,
532 unsigned long unused2, void *unused3)
533{
534 mutex_lock(&fullstop_mutex);
535 if (READ_ONCE(fullstop) == FULLSTOP_DONTSTOP) {
536 VERBOSE_TOROUT_STRING("Unscheduled system shutdown detected");
537 WRITE_ONCE(fullstop, FULLSTOP_SHUTDOWN);
538 } else {
539 pr_warn("Concurrent rmmod and shutdown illegal!\n");
540 }
541 mutex_unlock(&fullstop_mutex);
542 return NOTIFY_DONE;
543}
544
545static struct notifier_block torture_shutdown_nb = {
546 .notifier_call = torture_shutdown_notify,
547};
548
549/*
550 * Shut down the shutdown task. Say what??? Heh! This can happen if
551 * the torture module gets an rmmod before the shutdown time arrives. ;-)
552 */
553static void torture_shutdown_cleanup(void)
554{
555 unregister_reboot_notifier(&torture_shutdown_nb);
556 if (shutdown_task != NULL) {
557 VERBOSE_TOROUT_STRING("Stopping torture_shutdown task");
558 kthread_stop(shutdown_task);
559 }
560 shutdown_task = NULL;
561}
562
563/*
564 * Variables for stuttering, which means to periodically pause and
565 * restart testing in order to catch bugs that appear when load is
566 * suddenly applied to or removed from the system.
567 */
568static struct task_struct *stutter_task;
569static int stutter_pause_test;
570static int stutter;
571
572/*
573 * Block until the stutter interval ends. This must be called periodically
574 * by all running kthreads that need to be subject to stuttering.
575 */
576bool stutter_wait(const char *title)
577{
578 int spt;
579
580 cond_resched_tasks_rcu_qs();
581 spt = READ_ONCE(stutter_pause_test);
582 for (; spt; spt = READ_ONCE(stutter_pause_test)) {
583 if (spt == 1) {
584 schedule_timeout_interruptible(1);
585 } else if (spt == 2) {
586 while (READ_ONCE(stutter_pause_test))
587 cond_resched();
588 } else {
589 schedule_timeout_interruptible(round_jiffies_relative(HZ));
590 }
591 torture_shutdown_absorb(title);
592 }
593 return !!spt;
594}
595EXPORT_SYMBOL_GPL(stutter_wait);
596
597/*
598 * Cause the torture test to "stutter", starting and stopping all
599 * threads periodically.
600 */
601static int torture_stutter(void *arg)
602{
603 VERBOSE_TOROUT_STRING("torture_stutter task started");
604 do {
605 if (!torture_must_stop() && stutter > 1) {
606 WRITE_ONCE(stutter_pause_test, 1);
607 schedule_timeout_interruptible(stutter - 1);
608 WRITE_ONCE(stutter_pause_test, 2);
609 schedule_timeout_interruptible(1);
610 }
611 WRITE_ONCE(stutter_pause_test, 0);
612 if (!torture_must_stop())
613 schedule_timeout_interruptible(stutter);
614 torture_shutdown_absorb("torture_stutter");
615 } while (!torture_must_stop());
616 torture_kthread_stopping("torture_stutter");
617 return 0;
618}
619
620/*
621 * Initialize and kick off the torture_stutter kthread.
622 */
623int torture_stutter_init(const int s)
624{
625 stutter = s;
626 return torture_create_kthread(torture_stutter, NULL, stutter_task);
627}
628EXPORT_SYMBOL_GPL(torture_stutter_init);
629
630/*
631 * Cleanup after the torture_stutter kthread.
632 */
633static void torture_stutter_cleanup(void)
634{
635 if (!stutter_task)
636 return;
637 VERBOSE_TOROUT_STRING("Stopping torture_stutter task");
638 kthread_stop(stutter_task);
639 stutter_task = NULL;
640}
641
642/*
643 * Initialize torture module. Please note that this is -not- invoked via
644 * the usual module_init() mechanism, but rather by an explicit call from
645 * the client torture module. This call must be paired with a later
646 * torture_init_end().
647 *
648 * The runnable parameter points to a flag that controls whether or not
649 * the test is currently runnable. If there is no such flag, pass in NULL.
650 */
651bool torture_init_begin(char *ttype, int v)
652{
653 mutex_lock(&fullstop_mutex);
654 if (torture_type != NULL) {
655 pr_alert("torture_init_begin: Refusing %s init: %s running.\n",
656 ttype, torture_type);
657 pr_alert("torture_init_begin: One torture test at a time!\n");
658 mutex_unlock(&fullstop_mutex);
659 return false;
660 }
661 torture_type = ttype;
662 verbose = v;
663 fullstop = FULLSTOP_DONTSTOP;
664 return true;
665}
666EXPORT_SYMBOL_GPL(torture_init_begin);
667
668/*
669 * Tell the torture module that initialization is complete.
670 */
671void torture_init_end(void)
672{
673 mutex_unlock(&fullstop_mutex);
674 register_reboot_notifier(&torture_shutdown_nb);
675}
676EXPORT_SYMBOL_GPL(torture_init_end);
677
678/*
679 * Clean up torture module. Please note that this is -not- invoked via
680 * the usual module_exit() mechanism, but rather by an explicit call from
681 * the client torture module. Returns true if a race with system shutdown
682 * is detected, otherwise, all kthreads started by functions in this file
683 * will be shut down.
684 *
685 * This must be called before the caller starts shutting down its own
686 * kthreads.
687 *
688 * Both torture_cleanup_begin() and torture_cleanup_end() must be paired,
689 * in order to correctly perform the cleanup. They are separated because
690 * threads can still need to reference the torture_type type, thus nullify
691 * only after completing all other relevant calls.
692 */
693bool torture_cleanup_begin(void)
694{
695 mutex_lock(&fullstop_mutex);
696 if (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
697 pr_warn("Concurrent rmmod and shutdown illegal!\n");
698 mutex_unlock(&fullstop_mutex);
699 schedule_timeout_uninterruptible(10);
700 return true;
701 }
702 WRITE_ONCE(fullstop, FULLSTOP_RMMOD);
703 mutex_unlock(&fullstop_mutex);
704 torture_shutdown_cleanup();
705 torture_shuffle_cleanup();
706 torture_stutter_cleanup();
707 torture_onoff_cleanup();
708 return false;
709}
710EXPORT_SYMBOL_GPL(torture_cleanup_begin);
711
712void torture_cleanup_end(void)
713{
714 mutex_lock(&fullstop_mutex);
715 torture_type = NULL;
716 mutex_unlock(&fullstop_mutex);
717}
718EXPORT_SYMBOL_GPL(torture_cleanup_end);
719
720/*
721 * Is it time for the current torture test to stop?
722 */
723bool torture_must_stop(void)
724{
725 return torture_must_stop_irq() || kthread_should_stop();
726}
727EXPORT_SYMBOL_GPL(torture_must_stop);
728
729/*
730 * Is it time for the current torture test to stop? This is the irq-safe
731 * version, hence no check for kthread_should_stop().
732 */
733bool torture_must_stop_irq(void)
734{
735 return READ_ONCE(fullstop) != FULLSTOP_DONTSTOP;
736}
737EXPORT_SYMBOL_GPL(torture_must_stop_irq);
738
739/*
740 * Each kthread must wait for kthread_should_stop() before returning from
741 * its top-level function, otherwise segfaults ensue. This function
742 * prints a "stopping" message and waits for kthread_should_stop(), and
743 * should be called from all torture kthreads immediately prior to
744 * returning.
745 */
746void torture_kthread_stopping(char *title)
747{
748 char buf[128];
749
750 snprintf(buf, sizeof(buf), "Stopping %s", title);
751 VERBOSE_TOROUT_STRING(buf);
752 while (!kthread_should_stop()) {
753 torture_shutdown_absorb(title);
754 schedule_timeout_uninterruptible(1);
755 }
756}
757EXPORT_SYMBOL_GPL(torture_kthread_stopping);
758
759/*
760 * Create a generic torture kthread that is immediately runnable. If you
761 * need the kthread to be stopped so that you can do something to it before
762 * it starts, you will need to open-code your own.
763 */
764int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
765 char *f, struct task_struct **tp)
766{
767 int ret = 0;
768
769 VERBOSE_TOROUT_STRING(m);
770 *tp = kthread_run(fn, arg, "%s", s);
771 if (IS_ERR(*tp)) {
772 ret = PTR_ERR(*tp);
773 VERBOSE_TOROUT_ERRSTRING(f);
774 *tp = NULL;
775 }
776 torture_shuffle_task_register(*tp);
777 return ret;
778}
779EXPORT_SYMBOL_GPL(_torture_create_kthread);
780
781/*
782 * Stop a generic kthread, emitting a message.
783 */
784void _torture_stop_kthread(char *m, struct task_struct **tp)
785{
786 if (*tp == NULL)
787 return;
788 VERBOSE_TOROUT_STRING(m);
789 kthread_stop(*tp);
790 *tp = NULL;
791}
792EXPORT_SYMBOL_GPL(_torture_stop_kthread);
793