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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 <[email protected]>
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 <linux/sched/rt.h>
41#include "rcu/rcu.h"
42
43MODULE_DESCRIPTION("Common functions for in-kernel torture tests");
44MODULE_LICENSE("GPL");
45MODULE_AUTHOR("Paul E. McKenney <[email protected]>");
46
47static bool disable_onoff_at_boot;
48module_param(disable_onoff_at_boot, bool, 0444);
49
50static bool ftrace_dump_at_shutdown;
51module_param(ftrace_dump_at_shutdown, bool, 0444);
52
53static int verbose_sleep_frequency;
54module_param(verbose_sleep_frequency, int, 0444);
55
56static int verbose_sleep_duration = 1;
57module_param(verbose_sleep_duration, int, 0444);
58
59static int random_shuffle;
60module_param(random_shuffle, int, 0444);
61
62static char *torture_type;
63static int verbose;
64
65/* Mediate rmmod and system shutdown. Concurrent rmmod & shutdown illegal! */
66#define FULLSTOP_DONTSTOP 0 /* Normal operation. */
67#define FULLSTOP_SHUTDOWN 1 /* System shutdown with torture running. */
68#define FULLSTOP_RMMOD 2 /* Normal rmmod of torture. */
69static int fullstop = FULLSTOP_RMMOD;
70static DEFINE_MUTEX(fullstop_mutex);
71
72static atomic_t verbose_sleep_counter;
73
74/*
75 * Sleep if needed from VERBOSE_TOROUT*().
76 */
77void verbose_torout_sleep(void)
78{
79 if (verbose_sleep_frequency > 0 &&
80 verbose_sleep_duration > 0 &&
81 !(atomic_inc_return(&verbose_sleep_counter) % verbose_sleep_frequency))
82 schedule_timeout_uninterruptible(verbose_sleep_duration);
83}
84EXPORT_SYMBOL_GPL(verbose_torout_sleep);
85
86/*
87 * Schedule a high-resolution-timer sleep in nanoseconds, with a 32-bit
88 * nanosecond random fuzz. This function and its friends desynchronize
89 * testing from the timer wheel.
90 */
91int torture_hrtimeout_ns(ktime_t baset_ns, u32 fuzzt_ns, const enum hrtimer_mode mode,
92 struct torture_random_state *trsp)
93{
94 ktime_t hto = baset_ns;
95
96 if (trsp && fuzzt_ns)
97 hto += torture_random(trsp) % fuzzt_ns;
98 set_current_state(TASK_IDLE);
99 return schedule_hrtimeout(&hto, mode);
100}
101EXPORT_SYMBOL_GPL(torture_hrtimeout_ns);
102
103/*
104 * Schedule a high-resolution-timer sleep in microseconds, with a 32-bit
105 * nanosecond (not microsecond!) random fuzz.
106 */
107int torture_hrtimeout_us(u32 baset_us, u32 fuzzt_ns, struct torture_random_state *trsp)
108{
109 ktime_t baset_ns = baset_us * NSEC_PER_USEC;
110
111 return torture_hrtimeout_ns(baset_ns, fuzzt_ns, HRTIMER_MODE_REL, trsp);
112}
113EXPORT_SYMBOL_GPL(torture_hrtimeout_us);
114
115/*
116 * Schedule a high-resolution-timer sleep in milliseconds, with a 32-bit
117 * microsecond (not millisecond!) random fuzz.
118 */
119int torture_hrtimeout_ms(u32 baset_ms, u32 fuzzt_us, struct torture_random_state *trsp)
120{
121 ktime_t baset_ns = baset_ms * NSEC_PER_MSEC;
122 u32 fuzzt_ns;
123
124 if ((u32)~0U / NSEC_PER_USEC < fuzzt_us)
125 fuzzt_ns = (u32)~0U;
126 else
127 fuzzt_ns = fuzzt_us * NSEC_PER_USEC;
128 return torture_hrtimeout_ns(baset_ns, fuzzt_ns, HRTIMER_MODE_REL, trsp);
129}
130EXPORT_SYMBOL_GPL(torture_hrtimeout_ms);
131
132/*
133 * Schedule a high-resolution-timer sleep in jiffies, with an
134 * implied one-jiffy random fuzz. This is intended to replace calls to
135 * schedule_timeout_interruptible() and friends.
136 */
137int torture_hrtimeout_jiffies(u32 baset_j, struct torture_random_state *trsp)
138{
139 ktime_t baset_ns = jiffies_to_nsecs(baset_j);
140
141 return torture_hrtimeout_ns(baset_ns, jiffies_to_nsecs(1), HRTIMER_MODE_REL, trsp);
142}
143EXPORT_SYMBOL_GPL(torture_hrtimeout_jiffies);
144
145/*
146 * Schedule a high-resolution-timer sleep in milliseconds, with a 32-bit
147 * millisecond (not second!) random fuzz.
148 */
149int torture_hrtimeout_s(u32 baset_s, u32 fuzzt_ms, struct torture_random_state *trsp)
150{
151 ktime_t baset_ns = baset_s * NSEC_PER_SEC;
152 u32 fuzzt_ns;
153
154 if ((u32)~0U / NSEC_PER_MSEC < fuzzt_ms)
155 fuzzt_ns = (u32)~0U;
156 else
157 fuzzt_ns = fuzzt_ms * NSEC_PER_MSEC;
158 return torture_hrtimeout_ns(baset_ns, fuzzt_ns, HRTIMER_MODE_REL, trsp);
159}
160EXPORT_SYMBOL_GPL(torture_hrtimeout_s);
161
162#ifdef CONFIG_HOTPLUG_CPU
163
164/*
165 * Variables for online-offline handling. Only present if CPU hotplug
166 * is enabled, otherwise does nothing.
167 */
168
169static struct task_struct *onoff_task;
170static long onoff_holdoff;
171static long onoff_interval;
172static torture_ofl_func *onoff_f;
173static long n_offline_attempts;
174static long n_offline_successes;
175static unsigned long sum_offline;
176static int min_offline = -1;
177static int max_offline;
178static long n_online_attempts;
179static long n_online_successes;
180static unsigned long sum_online;
181static int min_online = -1;
182static int max_online;
183
184static int torture_online_cpus = NR_CPUS;
185
186/*
187 * Some torture testing leverages confusion as to the number of online
188 * CPUs. This function returns the torture-testing view of this number,
189 * which allows torture tests to load-balance appropriately.
190 */
191int torture_num_online_cpus(void)
192{
193 return READ_ONCE(torture_online_cpus);
194}
195EXPORT_SYMBOL_GPL(torture_num_online_cpus);
196
197/*
198 * Attempt to take a CPU offline. Return false if the CPU is already
199 * offline or if it is not subject to CPU-hotplug operations. The
200 * caller can detect other failures by looking at the statistics.
201 */
202bool torture_offline(int cpu, long *n_offl_attempts, long *n_offl_successes,
203 unsigned long *sum_offl, int *min_offl, int *max_offl)
204{
205 unsigned long delta;
206 int ret;
207 char *s;
208 unsigned long starttime;
209
210 if (!cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
211 return false;
212 if (num_online_cpus() <= 1)
213 return false; /* Can't offline the last CPU. */
214
215 if (verbose > 1)
216 pr_alert("%s" TORTURE_FLAG
217 "torture_onoff task: offlining %d\n",
218 torture_type, cpu);
219 starttime = jiffies;
220 (*n_offl_attempts)++;
221 ret = remove_cpu(cpu);
222 if (ret) {
223 s = "";
224 if (!rcu_inkernel_boot_has_ended() && ret == -EBUSY) {
225 // PCI probe frequently disables hotplug during boot.
226 (*n_offl_attempts)--;
227 s = " (-EBUSY forgiven during boot)";
228 }
229 if (verbose)
230 pr_alert("%s" TORTURE_FLAG
231 "torture_onoff task: offline %d failed%s: errno %d\n",
232 torture_type, cpu, s, ret);
233 } else {
234 if (verbose > 1)
235 pr_alert("%s" TORTURE_FLAG
236 "torture_onoff task: offlined %d\n",
237 torture_type, cpu);
238 if (onoff_f)
239 onoff_f();
240 (*n_offl_successes)++;
241 delta = jiffies - starttime;
242 *sum_offl += delta;
243 if (*min_offl < 0) {
244 *min_offl = delta;
245 *max_offl = delta;
246 }
247 if (*min_offl > delta)
248 *min_offl = delta;
249 if (*max_offl < delta)
250 *max_offl = delta;
251 WRITE_ONCE(torture_online_cpus, torture_online_cpus - 1);
252 WARN_ON_ONCE(torture_online_cpus <= 0);
253 }
254
255 return true;
256}
257EXPORT_SYMBOL_GPL(torture_offline);
258
259/*
260 * Attempt to bring a CPU online. Return false if the CPU is already
261 * online or if it is not subject to CPU-hotplug operations. The
262 * caller can detect other failures by looking at the statistics.
263 */
264bool torture_online(int cpu, long *n_onl_attempts, long *n_onl_successes,
265 unsigned long *sum_onl, int *min_onl, int *max_onl)
266{
267 unsigned long delta;
268 int ret;
269 char *s;
270 unsigned long starttime;
271
272 if (cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
273 return false;
274
275 if (verbose > 1)
276 pr_alert("%s" TORTURE_FLAG
277 "torture_onoff task: onlining %d\n",
278 torture_type, cpu);
279 starttime = jiffies;
280 (*n_onl_attempts)++;
281 ret = add_cpu(cpu);
282 if (ret) {
283 s = "";
284 if (!rcu_inkernel_boot_has_ended() && ret == -EBUSY) {
285 // PCI probe frequently disables hotplug during boot.
286 (*n_onl_attempts)--;
287 s = " (-EBUSY forgiven during boot)";
288 }
289 if (verbose)
290 pr_alert("%s" TORTURE_FLAG
291 "torture_onoff task: online %d failed%s: errno %d\n",
292 torture_type, cpu, s, ret);
293 } else {
294 if (verbose > 1)
295 pr_alert("%s" TORTURE_FLAG
296 "torture_onoff task: onlined %d\n",
297 torture_type, cpu);
298 (*n_onl_successes)++;
299 delta = jiffies - starttime;
300 *sum_onl += delta;
301 if (*min_onl < 0) {
302 *min_onl = delta;
303 *max_onl = delta;
304 }
305 if (*min_onl > delta)
306 *min_onl = delta;
307 if (*max_onl < delta)
308 *max_onl = delta;
309 WRITE_ONCE(torture_online_cpus, torture_online_cpus + 1);
310 }
311
312 return true;
313}
314EXPORT_SYMBOL_GPL(torture_online);
315
316/*
317 * Get everything online at the beginning and ends of tests.
318 */
319static void torture_online_all(char *phase)
320{
321 int cpu;
322 int ret;
323
324 for_each_possible_cpu(cpu) {
325 if (cpu_online(cpu))
326 continue;
327 ret = add_cpu(cpu);
328 if (ret && verbose) {
329 pr_alert("%s" TORTURE_FLAG
330 "%s: %s online %d: errno %d\n",
331 __func__, phase, torture_type, cpu, ret);
332 }
333 }
334}
335
336/*
337 * Execute random CPU-hotplug operations at the interval specified
338 * by the onoff_interval.
339 */
340static int
341torture_onoff(void *arg)
342{
343 int cpu;
344 int maxcpu = -1;
345 DEFINE_TORTURE_RANDOM(rand);
346
347 VERBOSE_TOROUT_STRING("torture_onoff task started");
348 for_each_online_cpu(cpu)
349 maxcpu = cpu;
350 WARN_ON(maxcpu < 0);
351 torture_online_all("Initial");
352 if (maxcpu == 0) {
353 VERBOSE_TOROUT_STRING("Only one CPU, so CPU-hotplug testing is disabled");
354 goto stop;
355 }
356
357 if (onoff_holdoff > 0) {
358 VERBOSE_TOROUT_STRING("torture_onoff begin holdoff");
359 torture_hrtimeout_jiffies(onoff_holdoff, &rand);
360 VERBOSE_TOROUT_STRING("torture_onoff end holdoff");
361 }
362 while (!rcu_inkernel_boot_has_ended())
363 schedule_timeout_interruptible(HZ / 10);
364 while (!torture_must_stop()) {
365 if (disable_onoff_at_boot && !rcu_inkernel_boot_has_ended()) {
366 torture_hrtimeout_jiffies(HZ / 10, &rand);
367 continue;
368 }
369 cpu = torture_random(&rand) % (maxcpu + 1);
370 if (!torture_offline(cpu,
371 &n_offline_attempts, &n_offline_successes,
372 &sum_offline, &min_offline, &max_offline))
373 torture_online(cpu,
374 &n_online_attempts, &n_online_successes,
375 &sum_online, &min_online, &max_online);
376 torture_hrtimeout_jiffies(onoff_interval, &rand);
377 }
378
379stop:
380 torture_kthread_stopping("torture_onoff");
381 torture_online_all("Final");
382 return 0;
383}
384
385#endif /* #ifdef CONFIG_HOTPLUG_CPU */
386
387/*
388 * Initiate online-offline handling.
389 */
390int torture_onoff_init(long ooholdoff, long oointerval, torture_ofl_func *f)
391{
392#ifdef CONFIG_HOTPLUG_CPU
393 onoff_holdoff = ooholdoff;
394 onoff_interval = oointerval;
395 onoff_f = f;
396 if (onoff_interval <= 0)
397 return 0;
398 return torture_create_kthread(torture_onoff, NULL, onoff_task);
399#else /* #ifdef CONFIG_HOTPLUG_CPU */
400 return 0;
401#endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
402}
403EXPORT_SYMBOL_GPL(torture_onoff_init);
404
405/*
406 * Clean up after online/offline testing.
407 */
408static void torture_onoff_cleanup(void)
409{
410#ifdef CONFIG_HOTPLUG_CPU
411 if (onoff_task == NULL)
412 return;
413 VERBOSE_TOROUT_STRING("Stopping torture_onoff task");
414 kthread_stop(onoff_task);
415 onoff_task = NULL;
416#endif /* #ifdef CONFIG_HOTPLUG_CPU */
417}
418
419/*
420 * Print online/offline testing statistics.
421 */
422void torture_onoff_stats(void)
423{
424#ifdef CONFIG_HOTPLUG_CPU
425 pr_cont("onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ",
426 n_online_successes, n_online_attempts,
427 n_offline_successes, n_offline_attempts,
428 min_online, max_online,
429 min_offline, max_offline,
430 sum_online, sum_offline, HZ);
431#endif /* #ifdef CONFIG_HOTPLUG_CPU */
432}
433EXPORT_SYMBOL_GPL(torture_onoff_stats);
434
435/*
436 * Were all the online/offline operations successful?
437 */
438bool torture_onoff_failures(void)
439{
440#ifdef CONFIG_HOTPLUG_CPU
441 return n_online_successes != n_online_attempts ||
442 n_offline_successes != n_offline_attempts;
443#else /* #ifdef CONFIG_HOTPLUG_CPU */
444 return false;
445#endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
446}
447EXPORT_SYMBOL_GPL(torture_onoff_failures);
448
449#define TORTURE_RANDOM_MULT 39916801 /* prime */
450#define TORTURE_RANDOM_ADD 479001701 /* prime */
451#define TORTURE_RANDOM_REFRESH 10000
452
453/*
454 * Crude but fast random-number generator. Uses a linear congruential
455 * generator, with occasional help from cpu_clock().
456 */
457unsigned long
458torture_random(struct torture_random_state *trsp)
459{
460 if (--trsp->trs_count < 0) {
461 trsp->trs_state += (unsigned long)local_clock() + raw_smp_processor_id();
462 trsp->trs_count = TORTURE_RANDOM_REFRESH;
463 }
464 trsp->trs_state = trsp->trs_state * TORTURE_RANDOM_MULT +
465 TORTURE_RANDOM_ADD;
466 return swahw32(trsp->trs_state);
467}
468EXPORT_SYMBOL_GPL(torture_random);
469
470/*
471 * Variables for shuffling. The idea is to ensure that each CPU stays
472 * idle for an extended period to test interactions with dyntick idle,
473 * as well as interactions with any per-CPU variables.
474 */
475struct shuffle_task {
476 struct list_head st_l;
477 struct task_struct *st_t;
478};
479
480static long shuffle_interval; /* In jiffies. */
481static struct task_struct *shuffler_task;
482static cpumask_var_t shuffle_tmp_mask;
483static int shuffle_idle_cpu; /* Force all torture tasks off this CPU */
484static struct list_head shuffle_task_list = LIST_HEAD_INIT(shuffle_task_list);
485static DEFINE_MUTEX(shuffle_task_mutex);
486
487/*
488 * Register a task to be shuffled. If there is no memory, just splat
489 * and don't bother registering.
490 */
491void torture_shuffle_task_register(struct task_struct *tp)
492{
493 struct shuffle_task *stp;
494
495 if (WARN_ON_ONCE(tp == NULL))
496 return;
497 stp = kmalloc_obj(*stp);
498 if (WARN_ON_ONCE(stp == NULL))
499 return;
500 stp->st_t = tp;
501 mutex_lock(&shuffle_task_mutex);
502 list_add(&stp->st_l, &shuffle_task_list);
503 mutex_unlock(&shuffle_task_mutex);
504}
505EXPORT_SYMBOL_GPL(torture_shuffle_task_register);
506
507/*
508 * Unregister all tasks, for example, at the end of the torture run.
509 */
510static void torture_shuffle_task_unregister_all(void)
511{
512 struct shuffle_task *stp;
513 struct shuffle_task *p;
514
515 mutex_lock(&shuffle_task_mutex);
516 list_for_each_entry_safe(stp, p, &shuffle_task_list, st_l) {
517 list_del(&stp->st_l);
518 kfree(stp);
519 }
520 mutex_unlock(&shuffle_task_mutex);
521}
522
523/* Shuffle tasks such that we allow shuffle_idle_cpu to become idle.
524 * A special case is when shuffle_idle_cpu = -1, in which case we allow
525 * the tasks to run on all CPUs.
526 */
527static void torture_shuffle_tasks(struct torture_random_state *trp)
528{
529 struct shuffle_task *stp;
530
531 cpumask_setall(shuffle_tmp_mask);
532 cpus_read_lock();
533
534 /* No point in shuffling if there is only one online CPU (ex: UP) */
535 if (num_online_cpus() == 1) {
536 cpus_read_unlock();
537 return;
538 }
539
540 /* Advance to the next CPU. Upon overflow, don't idle any CPUs. */
541 shuffle_idle_cpu = cpumask_next(shuffle_idle_cpu, shuffle_tmp_mask);
542 if (shuffle_idle_cpu >= nr_cpu_ids)
543 shuffle_idle_cpu = -1;
544 else
545 cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask);
546
547 mutex_lock(&shuffle_task_mutex);
548 list_for_each_entry(stp, &shuffle_task_list, st_l) {
549 if (!random_shuffle || torture_random(trp) & 0x1)
550 set_cpus_allowed_ptr(stp->st_t, shuffle_tmp_mask);
551 }
552 mutex_unlock(&shuffle_task_mutex);
553
554 cpus_read_unlock();
555}
556
557/* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
558 * system to become idle at a time and cut off its timer ticks. This is meant
559 * to test the support for such tickless idle CPU in RCU.
560 */
561static int torture_shuffle(void *arg)
562{
563 DEFINE_TORTURE_RANDOM(rand);
564
565 VERBOSE_TOROUT_STRING("torture_shuffle task started");
566 do {
567 torture_hrtimeout_jiffies(shuffle_interval, &rand);
568 torture_shuffle_tasks(&rand);
569 torture_shutdown_absorb("torture_shuffle");
570 } while (!torture_must_stop());
571 torture_kthread_stopping("torture_shuffle");
572 return 0;
573}
574
575/*
576 * Start the shuffler, with shuffint in jiffies.
577 */
578int torture_shuffle_init(long shuffint)
579{
580 int ret;
581
582 shuffle_interval = shuffint;
583
584 shuffle_idle_cpu = -1;
585
586 if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
587 TOROUT_ERRSTRING("Failed to alloc mask");
588 return -ENOMEM;
589 }
590
591 /* Create the shuffler thread */
592 ret = torture_create_kthread(torture_shuffle, NULL, shuffler_task);
593 if (ret)
594 free_cpumask_var(shuffle_tmp_mask);
595 return ret;
596}
597EXPORT_SYMBOL_GPL(torture_shuffle_init);
598
599/*
600 * Stop the shuffling.
601 */
602static void torture_shuffle_cleanup(void)
603{
604 torture_shuffle_task_unregister_all();
605 if (shuffler_task) {
606 VERBOSE_TOROUT_STRING("Stopping torture_shuffle task");
607 kthread_stop(shuffler_task);
608 free_cpumask_var(shuffle_tmp_mask);
609 }
610 shuffler_task = NULL;
611}
612
613/*
614 * Variables for auto-shutdown. This allows "lights out" torture runs
615 * to be fully scripted.
616 */
617static struct task_struct *shutdown_task;
618static ktime_t shutdown_time; /* time to system shutdown. */
619static void (*torture_shutdown_hook)(void);
620
621/*
622 * Absorb kthreads into a kernel function that won't return, so that
623 * they won't ever access module text or data again.
624 */
625void torture_shutdown_absorb(const char *title)
626{
627 while (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
628 pr_notice("torture thread %s parking due to system shutdown\n",
629 title);
630 schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
631 }
632}
633EXPORT_SYMBOL_GPL(torture_shutdown_absorb);
634
635/*
636 * Cause the torture test to shutdown the system after the test has
637 * run for the time specified by the shutdown_secs parameter.
638 */
639static int torture_shutdown(void *arg)
640{
641 ktime_t ktime_snap;
642
643 VERBOSE_TOROUT_STRING("torture_shutdown task started");
644 ktime_snap = ktime_get();
645 while (ktime_before(ktime_snap, shutdown_time) &&
646 !torture_must_stop()) {
647 if (verbose)
648 pr_alert("%s" TORTURE_FLAG
649 "torture_shutdown task: %llu ms remaining\n",
650 torture_type,
651 ktime_ms_delta(shutdown_time, ktime_snap));
652 set_current_state(TASK_INTERRUPTIBLE);
653 schedule_hrtimeout(&shutdown_time, HRTIMER_MODE_ABS);
654 ktime_snap = ktime_get();
655 }
656 if (torture_must_stop()) {
657 torture_kthread_stopping("torture_shutdown");
658 return 0;
659 }
660
661 /* OK, shut down the system. */
662
663 VERBOSE_TOROUT_STRING("torture_shutdown task shutting down system");
664 shutdown_task = NULL; /* Avoid self-kill deadlock. */
665 if (torture_shutdown_hook)
666 torture_shutdown_hook();
667 else
668 VERBOSE_TOROUT_STRING("No torture_shutdown_hook(), skipping.");
669 if (ftrace_dump_at_shutdown)
670 rcu_ftrace_dump(DUMP_ALL);
671 kernel_power_off(); /* Shut down the system. */
672 return 0;
673}
674
675/*
676 * Start up the shutdown task.
677 */
678int torture_shutdown_init(int ssecs, void (*cleanup)(void))
679{
680 torture_shutdown_hook = cleanup;
681 if (ssecs > 0) {
682 shutdown_time = ktime_add(ktime_get(), ktime_set(ssecs, 0));
683 return torture_create_kthread(torture_shutdown, NULL,
684 shutdown_task);
685 }
686 return 0;
687}
688EXPORT_SYMBOL_GPL(torture_shutdown_init);
689
690/*
691 * Detect and respond to a system shutdown.
692 */
693static int torture_shutdown_notify(struct notifier_block *unused1,
694 unsigned long unused2, void *unused3)
695{
696 mutex_lock(&fullstop_mutex);
697 if (READ_ONCE(fullstop) == FULLSTOP_DONTSTOP) {
698 VERBOSE_TOROUT_STRING("Unscheduled system shutdown detected");
699 WRITE_ONCE(fullstop, FULLSTOP_SHUTDOWN);
700 } else {
701 pr_warn("Concurrent rmmod and shutdown illegal!\n");
702 }
703 mutex_unlock(&fullstop_mutex);
704 return NOTIFY_DONE;
705}
706
707static struct notifier_block torture_shutdown_nb = {
708 .notifier_call = torture_shutdown_notify,
709};
710
711/*
712 * Shut down the shutdown task. Say what??? Heh! This can happen if
713 * the torture module gets an rmmod before the shutdown time arrives. ;-)
714 */
715static void torture_shutdown_cleanup(void)
716{
717 unregister_reboot_notifier(&torture_shutdown_nb);
718 if (shutdown_task != NULL) {
719 VERBOSE_TOROUT_STRING("Stopping torture_shutdown task");
720 kthread_stop(shutdown_task);
721 }
722 shutdown_task = NULL;
723}
724
725/*
726 * Variables for stuttering, which means to periodically pause and
727 * restart testing in order to catch bugs that appear when load is
728 * suddenly applied to or removed from the system.
729 */
730static struct task_struct *stutter_task;
731static ktime_t stutter_till_abs_time;
732static int stutter;
733static int stutter_gap;
734
735/*
736 * Block until the stutter interval ends. This must be called periodically
737 * by all running kthreads that need to be subject to stuttering.
738 */
739bool stutter_wait(const char *title)
740{
741 bool ret = false;
742 ktime_t till_ns;
743
744 cond_resched_tasks_rcu_qs();
745 till_ns = READ_ONCE(stutter_till_abs_time);
746 if (till_ns && ktime_before(ktime_get(), till_ns)) {
747 torture_hrtimeout_ns(till_ns, 0, HRTIMER_MODE_ABS, NULL);
748 ret = true;
749 }
750 torture_shutdown_absorb(title);
751 return ret;
752}
753EXPORT_SYMBOL_GPL(stutter_wait);
754
755/*
756 * Cause the torture test to "stutter", starting and stopping all
757 * threads periodically.
758 */
759static int torture_stutter(void *arg)
760{
761 ktime_t till_ns;
762
763 VERBOSE_TOROUT_STRING("torture_stutter task started");
764 do {
765 if (!torture_must_stop() && stutter > 1) {
766 till_ns = ktime_add_ns(ktime_get(),
767 jiffies_to_nsecs(stutter));
768 WRITE_ONCE(stutter_till_abs_time, till_ns);
769 torture_hrtimeout_jiffies(stutter - 1, NULL);
770 }
771 if (!torture_must_stop())
772 torture_hrtimeout_jiffies(stutter_gap, NULL);
773 torture_shutdown_absorb("torture_stutter");
774 } while (!torture_must_stop());
775 torture_kthread_stopping("torture_stutter");
776 return 0;
777}
778
779/*
780 * Initialize and kick off the torture_stutter kthread.
781 */
782int torture_stutter_init(const int s, const int sgap)
783{
784 stutter = s;
785 stutter_gap = sgap;
786 return torture_create_kthread(torture_stutter, NULL, stutter_task);
787}
788EXPORT_SYMBOL_GPL(torture_stutter_init);
789
790/*
791 * Cleanup after the torture_stutter kthread.
792 */
793static void torture_stutter_cleanup(void)
794{
795 if (!stutter_task)
796 return;
797 VERBOSE_TOROUT_STRING("Stopping torture_stutter task");
798 kthread_stop(stutter_task);
799 stutter_task = NULL;
800}
801
802static unsigned long torture_init_jiffies;
803
804static void
805torture_print_module_parms(void)
806{
807 pr_alert("torture module --- %s: disable_onoff_at_boot=%d ftrace_dump_at_shutdown=%d verbose_sleep_frequency=%d verbose_sleep_duration=%d random_shuffle=%d%s\n",
808 torture_type, disable_onoff_at_boot, ftrace_dump_at_shutdown, verbose_sleep_frequency, verbose_sleep_duration, random_shuffle,
809 rcu_inkernel_boot_has_ended() ? "" : " still booting");
810}
811
812/*
813 * Initialize torture module. Please note that this is -not- invoked via
814 * the usual module_init() mechanism, but rather by an explicit call from
815 * the client torture module. This call must be paired with a later
816 * torture_init_end().
817 *
818 * The runnable parameter points to a flag that controls whether or not
819 * the test is currently runnable. If there is no such flag, pass in NULL.
820 */
821bool torture_init_begin(char *ttype, int v)
822{
823 mutex_lock(&fullstop_mutex);
824 if (torture_type != NULL) {
825 pr_alert("%s: Refusing %s init: %s running.\n",
826 __func__, ttype, torture_type);
827 pr_alert("%s: One torture test at a time!\n", __func__);
828 mutex_unlock(&fullstop_mutex);
829 return false;
830 }
831 torture_type = ttype;
832 verbose = v;
833 fullstop = FULLSTOP_DONTSTOP;
834 WRITE_ONCE(torture_init_jiffies, jiffies); // Lockless reads.
835 torture_print_module_parms();
836 return true;
837}
838EXPORT_SYMBOL_GPL(torture_init_begin);
839
840/*
841 * Tell the torture module that initialization is complete.
842 */
843void torture_init_end(void)
844{
845 mutex_unlock(&fullstop_mutex);
846 register_reboot_notifier(&torture_shutdown_nb);
847}
848EXPORT_SYMBOL_GPL(torture_init_end);
849
850/*
851 * Get the torture_init_begin()-time value of the jiffies counter.
852 */
853unsigned long get_torture_init_jiffies(void)
854{
855 return READ_ONCE(torture_init_jiffies);
856}
857EXPORT_SYMBOL_GPL(get_torture_init_jiffies);
858
859/*
860 * Clean up torture module. Please note that this is -not- invoked via
861 * the usual module_exit() mechanism, but rather by an explicit call from
862 * the client torture module. Returns true if a race with system shutdown
863 * is detected, otherwise, all kthreads started by functions in this file
864 * will be shut down.
865 *
866 * This must be called before the caller starts shutting down its own
867 * kthreads.
868 *
869 * Both torture_cleanup_begin() and torture_cleanup_end() must be paired,
870 * in order to correctly perform the cleanup. They are separated because
871 * threads can still need to reference the torture_type type, thus nullify
872 * only after completing all other relevant calls.
873 */
874bool torture_cleanup_begin(void)
875{
876 mutex_lock(&fullstop_mutex);
877 if (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
878 pr_warn("Concurrent rmmod and shutdown illegal!\n");
879 mutex_unlock(&fullstop_mutex);
880 schedule_timeout_uninterruptible(10);
881 return true;
882 }
883 WRITE_ONCE(fullstop, FULLSTOP_RMMOD);
884 mutex_unlock(&fullstop_mutex);
885 torture_shutdown_cleanup();
886 torture_shuffle_cleanup();
887 torture_stutter_cleanup();
888 torture_onoff_cleanup();
889 return false;
890}
891EXPORT_SYMBOL_GPL(torture_cleanup_begin);
892
893void torture_cleanup_end(void)
894{
895 mutex_lock(&fullstop_mutex);
896 torture_type = NULL;
897 mutex_unlock(&fullstop_mutex);
898}
899EXPORT_SYMBOL_GPL(torture_cleanup_end);
900
901/*
902 * Is it time for the current torture test to stop?
903 */
904bool torture_must_stop(void)
905{
906 return torture_must_stop_irq() || kthread_should_stop();
907}
908EXPORT_SYMBOL_GPL(torture_must_stop);
909
910/*
911 * Is it time for the current torture test to stop? This is the irq-safe
912 * version, hence no check for kthread_should_stop().
913 */
914bool torture_must_stop_irq(void)
915{
916 return READ_ONCE(fullstop) != FULLSTOP_DONTSTOP;
917}
918EXPORT_SYMBOL_GPL(torture_must_stop_irq);
919
920/*
921 * Each kthread must wait for kthread_should_stop() before returning from
922 * its top-level function, otherwise segfaults ensue. This function
923 * prints a "stopping" message and waits for kthread_should_stop(), and
924 * should be called from all torture kthreads immediately prior to
925 * returning.
926 */
927void torture_kthread_stopping(char *title)
928{
929 char buf[128];
930
931 snprintf(buf, sizeof(buf), "%s is stopping", title);
932 VERBOSE_TOROUT_STRING(buf);
933 while (!kthread_should_stop()) {
934 torture_shutdown_absorb(title);
935 schedule_timeout_uninterruptible(HZ / 20);
936 }
937}
938EXPORT_SYMBOL_GPL(torture_kthread_stopping);
939
940/*
941 * Create a generic torture kthread that is immediately runnable. If you
942 * need the kthread to be stopped so that you can do something to it before
943 * it starts, you will need to open-code your own.
944 */
945int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
946 char *f, struct task_struct **tp, void (*cbf)(struct task_struct *tp))
947{
948 int ret = 0;
949
950 VERBOSE_TOROUT_STRING(m);
951 *tp = kthread_create(fn, arg, "%s", s);
952 if (IS_ERR(*tp)) {
953 ret = PTR_ERR(*tp);
954 TOROUT_ERRSTRING(f);
955 *tp = NULL;
956 return ret;
957 }
958
959 if (cbf)
960 cbf(*tp);
961
962 wake_up_process(*tp); // Process is sleeping, so ordering provided.
963 torture_shuffle_task_register(*tp);
964 return ret;
965}
966EXPORT_SYMBOL_GPL(_torture_create_kthread);
967
968/*
969 * Stop a generic kthread, emitting a message.
970 */
971void _torture_stop_kthread(char *m, struct task_struct **tp)
972{
973 if (*tp == NULL)
974 return;
975 VERBOSE_TOROUT_STRING(m);
976 kthread_stop(*tp);
977 *tp = NULL;
978}
979EXPORT_SYMBOL_GPL(_torture_stop_kthread);
980
981/*
982 * Set the specified task's niceness value, saturating at limits.
983 * Saturating noisily, but saturating.
984 */
985void torture_sched_set_normal(struct task_struct *t, int nice)
986{
987 int realnice = nice;
988
989 if (WARN_ON_ONCE(realnice > MAX_NICE))
990 realnice = MAX_NICE;
991 if (WARN_ON_ONCE(realnice < MIN_NICE))
992 realnice = MIN_NICE;
993 sched_set_normal(t, realnice);
994}
995EXPORT_SYMBOL_GPL(torture_sched_set_normal);