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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 <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 <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 <paulmck@linux.ibm.com>");
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)
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 (!torture_must_stop()) {
363 if (disable_onoff_at_boot && !rcu_inkernel_boot_has_ended()) {
364 torture_hrtimeout_jiffies(HZ / 10, &rand);
365 continue;
366 }
367 cpu = torture_random(&rand) % (maxcpu + 1);
368 if (!torture_offline(cpu,
369 &n_offline_attempts, &n_offline_successes,
370 &sum_offline, &min_offline, &max_offline))
371 torture_online(cpu,
372 &n_online_attempts, &n_online_successes,
373 &sum_online, &min_online, &max_online);
374 torture_hrtimeout_jiffies(onoff_interval, &rand);
375 }
376
377stop:
378 torture_kthread_stopping("torture_onoff");
379 torture_online_all("Final");
380 return 0;
381}
382
383#endif /* #ifdef CONFIG_HOTPLUG_CPU */
384
385/*
386 * Initiate online-offline handling.
387 */
388int torture_onoff_init(long ooholdoff, long oointerval, torture_ofl_func *f)
389{
390#ifdef CONFIG_HOTPLUG_CPU
391 onoff_holdoff = ooholdoff;
392 onoff_interval = oointerval;
393 onoff_f = f;
394 if (onoff_interval <= 0)
395 return 0;
396 return torture_create_kthread(torture_onoff, NULL, onoff_task);
397#else /* #ifdef CONFIG_HOTPLUG_CPU */
398 return 0;
399#endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
400}
401EXPORT_SYMBOL_GPL(torture_onoff_init);
402
403/*
404 * Clean up after online/offline testing.
405 */
406static void torture_onoff_cleanup(void)
407{
408#ifdef CONFIG_HOTPLUG_CPU
409 if (onoff_task == NULL)
410 return;
411 VERBOSE_TOROUT_STRING("Stopping torture_onoff task");
412 kthread_stop(onoff_task);
413 onoff_task = NULL;
414#endif /* #ifdef CONFIG_HOTPLUG_CPU */
415}
416
417/*
418 * Print online/offline testing statistics.
419 */
420void torture_onoff_stats(void)
421{
422#ifdef CONFIG_HOTPLUG_CPU
423 pr_cont("onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ",
424 n_online_successes, n_online_attempts,
425 n_offline_successes, n_offline_attempts,
426 min_online, max_online,
427 min_offline, max_offline,
428 sum_online, sum_offline, HZ);
429#endif /* #ifdef CONFIG_HOTPLUG_CPU */
430}
431EXPORT_SYMBOL_GPL(torture_onoff_stats);
432
433/*
434 * Were all the online/offline operations successful?
435 */
436bool torture_onoff_failures(void)
437{
438#ifdef CONFIG_HOTPLUG_CPU
439 return n_online_successes != n_online_attempts ||
440 n_offline_successes != n_offline_attempts;
441#else /* #ifdef CONFIG_HOTPLUG_CPU */
442 return false;
443#endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
444}
445EXPORT_SYMBOL_GPL(torture_onoff_failures);
446
447#define TORTURE_RANDOM_MULT 39916801 /* prime */
448#define TORTURE_RANDOM_ADD 479001701 /* prime */
449#define TORTURE_RANDOM_REFRESH 10000
450
451/*
452 * Crude but fast random-number generator. Uses a linear congruential
453 * generator, with occasional help from cpu_clock().
454 */
455unsigned long
456torture_random(struct torture_random_state *trsp)
457{
458 if (--trsp->trs_count < 0) {
459 trsp->trs_state += (unsigned long)local_clock() + raw_smp_processor_id();
460 trsp->trs_count = TORTURE_RANDOM_REFRESH;
461 }
462 trsp->trs_state = trsp->trs_state * TORTURE_RANDOM_MULT +
463 TORTURE_RANDOM_ADD;
464 return swahw32(trsp->trs_state);
465}
466EXPORT_SYMBOL_GPL(torture_random);
467
468/*
469 * Variables for shuffling. The idea is to ensure that each CPU stays
470 * idle for an extended period to test interactions with dyntick idle,
471 * as well as interactions with any per-CPU variables.
472 */
473struct shuffle_task {
474 struct list_head st_l;
475 struct task_struct *st_t;
476};
477
478static long shuffle_interval; /* In jiffies. */
479static struct task_struct *shuffler_task;
480static cpumask_var_t shuffle_tmp_mask;
481static int shuffle_idle_cpu; /* Force all torture tasks off this CPU */
482static struct list_head shuffle_task_list = LIST_HEAD_INIT(shuffle_task_list);
483static DEFINE_MUTEX(shuffle_task_mutex);
484
485/*
486 * Register a task to be shuffled. If there is no memory, just splat
487 * and don't bother registering.
488 */
489void torture_shuffle_task_register(struct task_struct *tp)
490{
491 struct shuffle_task *stp;
492
493 if (WARN_ON_ONCE(tp == NULL))
494 return;
495 stp = kmalloc(sizeof(*stp), GFP_KERNEL);
496 if (WARN_ON_ONCE(stp == NULL))
497 return;
498 stp->st_t = tp;
499 mutex_lock(&shuffle_task_mutex);
500 list_add(&stp->st_l, &shuffle_task_list);
501 mutex_unlock(&shuffle_task_mutex);
502}
503EXPORT_SYMBOL_GPL(torture_shuffle_task_register);
504
505/*
506 * Unregister all tasks, for example, at the end of the torture run.
507 */
508static void torture_shuffle_task_unregister_all(void)
509{
510 struct shuffle_task *stp;
511 struct shuffle_task *p;
512
513 mutex_lock(&shuffle_task_mutex);
514 list_for_each_entry_safe(stp, p, &shuffle_task_list, st_l) {
515 list_del(&stp->st_l);
516 kfree(stp);
517 }
518 mutex_unlock(&shuffle_task_mutex);
519}
520
521/* Shuffle tasks such that we allow shuffle_idle_cpu to become idle.
522 * A special case is when shuffle_idle_cpu = -1, in which case we allow
523 * the tasks to run on all CPUs.
524 */
525static void torture_shuffle_tasks(struct torture_random_state *trp)
526{
527 struct shuffle_task *stp;
528
529 cpumask_setall(shuffle_tmp_mask);
530 cpus_read_lock();
531
532 /* No point in shuffling if there is only one online CPU (ex: UP) */
533 if (num_online_cpus() == 1) {
534 cpus_read_unlock();
535 return;
536 }
537
538 /* Advance to the next CPU. Upon overflow, don't idle any CPUs. */
539 shuffle_idle_cpu = cpumask_next(shuffle_idle_cpu, shuffle_tmp_mask);
540 if (shuffle_idle_cpu >= nr_cpu_ids)
541 shuffle_idle_cpu = -1;
542 else
543 cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask);
544
545 mutex_lock(&shuffle_task_mutex);
546 list_for_each_entry(stp, &shuffle_task_list, st_l) {
547 if (!random_shuffle || torture_random(trp) & 0x1)
548 set_cpus_allowed_ptr(stp->st_t, shuffle_tmp_mask);
549 }
550 mutex_unlock(&shuffle_task_mutex);
551
552 cpus_read_unlock();
553}
554
555/* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
556 * system to become idle at a time and cut off its timer ticks. This is meant
557 * to test the support for such tickless idle CPU in RCU.
558 */
559static int torture_shuffle(void *arg)
560{
561 DEFINE_TORTURE_RANDOM(rand);
562
563 VERBOSE_TOROUT_STRING("torture_shuffle task started");
564 do {
565 torture_hrtimeout_jiffies(shuffle_interval, &rand);
566 torture_shuffle_tasks(&rand);
567 torture_shutdown_absorb("torture_shuffle");
568 } while (!torture_must_stop());
569 torture_kthread_stopping("torture_shuffle");
570 return 0;
571}
572
573/*
574 * Start the shuffler, with shuffint in jiffies.
575 */
576int torture_shuffle_init(long shuffint)
577{
578 shuffle_interval = shuffint;
579
580 shuffle_idle_cpu = -1;
581
582 if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
583 TOROUT_ERRSTRING("Failed to alloc mask");
584 return -ENOMEM;
585 }
586
587 /* Create the shuffler thread */
588 return torture_create_kthread(torture_shuffle, NULL, shuffler_task);
589}
590EXPORT_SYMBOL_GPL(torture_shuffle_init);
591
592/*
593 * Stop the shuffling.
594 */
595static void torture_shuffle_cleanup(void)
596{
597 torture_shuffle_task_unregister_all();
598 if (shuffler_task) {
599 VERBOSE_TOROUT_STRING("Stopping torture_shuffle task");
600 kthread_stop(shuffler_task);
601 free_cpumask_var(shuffle_tmp_mask);
602 }
603 shuffler_task = NULL;
604}
605
606/*
607 * Variables for auto-shutdown. This allows "lights out" torture runs
608 * to be fully scripted.
609 */
610static struct task_struct *shutdown_task;
611static ktime_t shutdown_time; /* time to system shutdown. */
612static void (*torture_shutdown_hook)(void);
613
614/*
615 * Absorb kthreads into a kernel function that won't return, so that
616 * they won't ever access module text or data again.
617 */
618void torture_shutdown_absorb(const char *title)
619{
620 while (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
621 pr_notice("torture thread %s parking due to system shutdown\n",
622 title);
623 schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
624 }
625}
626EXPORT_SYMBOL_GPL(torture_shutdown_absorb);
627
628/*
629 * Cause the torture test to shutdown the system after the test has
630 * run for the time specified by the shutdown_secs parameter.
631 */
632static int torture_shutdown(void *arg)
633{
634 ktime_t ktime_snap;
635
636 VERBOSE_TOROUT_STRING("torture_shutdown task started");
637 ktime_snap = ktime_get();
638 while (ktime_before(ktime_snap, shutdown_time) &&
639 !torture_must_stop()) {
640 if (verbose)
641 pr_alert("%s" TORTURE_FLAG
642 "torture_shutdown task: %llu ms remaining\n",
643 torture_type,
644 ktime_ms_delta(shutdown_time, ktime_snap));
645 set_current_state(TASK_INTERRUPTIBLE);
646 schedule_hrtimeout(&shutdown_time, HRTIMER_MODE_ABS);
647 ktime_snap = ktime_get();
648 }
649 if (torture_must_stop()) {
650 torture_kthread_stopping("torture_shutdown");
651 return 0;
652 }
653
654 /* OK, shut down the system. */
655
656 VERBOSE_TOROUT_STRING("torture_shutdown task shutting down system");
657 shutdown_task = NULL; /* Avoid self-kill deadlock. */
658 if (torture_shutdown_hook)
659 torture_shutdown_hook();
660 else
661 VERBOSE_TOROUT_STRING("No torture_shutdown_hook(), skipping.");
662 if (ftrace_dump_at_shutdown)
663 rcu_ftrace_dump(DUMP_ALL);
664 kernel_power_off(); /* Shut down the system. */
665 return 0;
666}
667
668/*
669 * Start up the shutdown task.
670 */
671int torture_shutdown_init(int ssecs, void (*cleanup)(void))
672{
673 torture_shutdown_hook = cleanup;
674 if (ssecs > 0) {
675 shutdown_time = ktime_add(ktime_get(), ktime_set(ssecs, 0));
676 return torture_create_kthread(torture_shutdown, NULL,
677 shutdown_task);
678 }
679 return 0;
680}
681EXPORT_SYMBOL_GPL(torture_shutdown_init);
682
683/*
684 * Detect and respond to a system shutdown.
685 */
686static int torture_shutdown_notify(struct notifier_block *unused1,
687 unsigned long unused2, void *unused3)
688{
689 mutex_lock(&fullstop_mutex);
690 if (READ_ONCE(fullstop) == FULLSTOP_DONTSTOP) {
691 VERBOSE_TOROUT_STRING("Unscheduled system shutdown detected");
692 WRITE_ONCE(fullstop, FULLSTOP_SHUTDOWN);
693 } else {
694 pr_warn("Concurrent rmmod and shutdown illegal!\n");
695 }
696 mutex_unlock(&fullstop_mutex);
697 return NOTIFY_DONE;
698}
699
700static struct notifier_block torture_shutdown_nb = {
701 .notifier_call = torture_shutdown_notify,
702};
703
704/*
705 * Shut down the shutdown task. Say what??? Heh! This can happen if
706 * the torture module gets an rmmod before the shutdown time arrives. ;-)
707 */
708static void torture_shutdown_cleanup(void)
709{
710 unregister_reboot_notifier(&torture_shutdown_nb);
711 if (shutdown_task != NULL) {
712 VERBOSE_TOROUT_STRING("Stopping torture_shutdown task");
713 kthread_stop(shutdown_task);
714 }
715 shutdown_task = NULL;
716}
717
718/*
719 * Variables for stuttering, which means to periodically pause and
720 * restart testing in order to catch bugs that appear when load is
721 * suddenly applied to or removed from the system.
722 */
723static struct task_struct *stutter_task;
724static ktime_t stutter_till_abs_time;
725static int stutter;
726static int stutter_gap;
727
728/*
729 * Block until the stutter interval ends. This must be called periodically
730 * by all running kthreads that need to be subject to stuttering.
731 */
732bool stutter_wait(const char *title)
733{
734 bool ret = false;
735 ktime_t till_ns;
736
737 cond_resched_tasks_rcu_qs();
738 till_ns = READ_ONCE(stutter_till_abs_time);
739 if (till_ns && ktime_before(ktime_get(), till_ns)) {
740 torture_hrtimeout_ns(till_ns, 0, HRTIMER_MODE_ABS, NULL);
741 ret = true;
742 }
743 torture_shutdown_absorb(title);
744 return ret;
745}
746EXPORT_SYMBOL_GPL(stutter_wait);
747
748/*
749 * Cause the torture test to "stutter", starting and stopping all
750 * threads periodically.
751 */
752static int torture_stutter(void *arg)
753{
754 ktime_t till_ns;
755
756 VERBOSE_TOROUT_STRING("torture_stutter task started");
757 do {
758 if (!torture_must_stop() && stutter > 1) {
759 till_ns = ktime_add_ns(ktime_get(),
760 jiffies_to_nsecs(stutter));
761 WRITE_ONCE(stutter_till_abs_time, till_ns);
762 torture_hrtimeout_jiffies(stutter - 1, NULL);
763 }
764 if (!torture_must_stop())
765 torture_hrtimeout_jiffies(stutter_gap, NULL);
766 torture_shutdown_absorb("torture_stutter");
767 } while (!torture_must_stop());
768 torture_kthread_stopping("torture_stutter");
769 return 0;
770}
771
772/*
773 * Initialize and kick off the torture_stutter kthread.
774 */
775int torture_stutter_init(const int s, const int sgap)
776{
777 stutter = s;
778 stutter_gap = sgap;
779 return torture_create_kthread(torture_stutter, NULL, stutter_task);
780}
781EXPORT_SYMBOL_GPL(torture_stutter_init);
782
783/*
784 * Cleanup after the torture_stutter kthread.
785 */
786static void torture_stutter_cleanup(void)
787{
788 if (!stutter_task)
789 return;
790 VERBOSE_TOROUT_STRING("Stopping torture_stutter task");
791 kthread_stop(stutter_task);
792 stutter_task = NULL;
793}
794
795static void
796torture_print_module_parms(void)
797{
798 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\n",
799 torture_type, disable_onoff_at_boot, ftrace_dump_at_shutdown, verbose_sleep_frequency, verbose_sleep_duration, random_shuffle);
800}
801
802/*
803 * Initialize torture module. Please note that this is -not- invoked via
804 * the usual module_init() mechanism, but rather by an explicit call from
805 * the client torture module. This call must be paired with a later
806 * torture_init_end().
807 *
808 * The runnable parameter points to a flag that controls whether or not
809 * the test is currently runnable. If there is no such flag, pass in NULL.
810 */
811bool torture_init_begin(char *ttype, int v)
812{
813 mutex_lock(&fullstop_mutex);
814 if (torture_type != NULL) {
815 pr_alert("%s: Refusing %s init: %s running.\n",
816 __func__, ttype, torture_type);
817 pr_alert("%s: One torture test at a time!\n", __func__);
818 mutex_unlock(&fullstop_mutex);
819 return false;
820 }
821 torture_type = ttype;
822 verbose = v;
823 fullstop = FULLSTOP_DONTSTOP;
824 torture_print_module_parms();
825 return true;
826}
827EXPORT_SYMBOL_GPL(torture_init_begin);
828
829/*
830 * Tell the torture module that initialization is complete.
831 */
832void torture_init_end(void)
833{
834 mutex_unlock(&fullstop_mutex);
835 register_reboot_notifier(&torture_shutdown_nb);
836}
837EXPORT_SYMBOL_GPL(torture_init_end);
838
839/*
840 * Clean up torture module. Please note that this is -not- invoked via
841 * the usual module_exit() mechanism, but rather by an explicit call from
842 * the client torture module. Returns true if a race with system shutdown
843 * is detected, otherwise, all kthreads started by functions in this file
844 * will be shut down.
845 *
846 * This must be called before the caller starts shutting down its own
847 * kthreads.
848 *
849 * Both torture_cleanup_begin() and torture_cleanup_end() must be paired,
850 * in order to correctly perform the cleanup. They are separated because
851 * threads can still need to reference the torture_type type, thus nullify
852 * only after completing all other relevant calls.
853 */
854bool torture_cleanup_begin(void)
855{
856 mutex_lock(&fullstop_mutex);
857 if (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
858 pr_warn("Concurrent rmmod and shutdown illegal!\n");
859 mutex_unlock(&fullstop_mutex);
860 schedule_timeout_uninterruptible(10);
861 return true;
862 }
863 WRITE_ONCE(fullstop, FULLSTOP_RMMOD);
864 mutex_unlock(&fullstop_mutex);
865 torture_shutdown_cleanup();
866 torture_shuffle_cleanup();
867 torture_stutter_cleanup();
868 torture_onoff_cleanup();
869 return false;
870}
871EXPORT_SYMBOL_GPL(torture_cleanup_begin);
872
873void torture_cleanup_end(void)
874{
875 mutex_lock(&fullstop_mutex);
876 torture_type = NULL;
877 mutex_unlock(&fullstop_mutex);
878}
879EXPORT_SYMBOL_GPL(torture_cleanup_end);
880
881/*
882 * Is it time for the current torture test to stop?
883 */
884bool torture_must_stop(void)
885{
886 return torture_must_stop_irq() || kthread_should_stop();
887}
888EXPORT_SYMBOL_GPL(torture_must_stop);
889
890/*
891 * Is it time for the current torture test to stop? This is the irq-safe
892 * version, hence no check for kthread_should_stop().
893 */
894bool torture_must_stop_irq(void)
895{
896 return READ_ONCE(fullstop) != FULLSTOP_DONTSTOP;
897}
898EXPORT_SYMBOL_GPL(torture_must_stop_irq);
899
900/*
901 * Each kthread must wait for kthread_should_stop() before returning from
902 * its top-level function, otherwise segfaults ensue. This function
903 * prints a "stopping" message and waits for kthread_should_stop(), and
904 * should be called from all torture kthreads immediately prior to
905 * returning.
906 */
907void torture_kthread_stopping(char *title)
908{
909 char buf[128];
910
911 snprintf(buf, sizeof(buf), "%s is stopping", title);
912 VERBOSE_TOROUT_STRING(buf);
913 while (!kthread_should_stop()) {
914 torture_shutdown_absorb(title);
915 schedule_timeout_uninterruptible(HZ / 20);
916 }
917}
918EXPORT_SYMBOL_GPL(torture_kthread_stopping);
919
920/*
921 * Create a generic torture kthread that is immediately runnable. If you
922 * need the kthread to be stopped so that you can do something to it before
923 * it starts, you will need to open-code your own.
924 */
925int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
926 char *f, struct task_struct **tp, void (*cbf)(struct task_struct *tp))
927{
928 int ret = 0;
929
930 VERBOSE_TOROUT_STRING(m);
931 *tp = kthread_create(fn, arg, "%s", s);
932 if (IS_ERR(*tp)) {
933 ret = PTR_ERR(*tp);
934 TOROUT_ERRSTRING(f);
935 *tp = NULL;
936 return ret;
937 }
938
939 if (cbf)
940 cbf(*tp);
941
942 wake_up_process(*tp); // Process is sleeping, so ordering provided.
943 torture_shuffle_task_register(*tp);
944 return ret;
945}
946EXPORT_SYMBOL_GPL(_torture_create_kthread);
947
948/*
949 * Stop a generic kthread, emitting a message.
950 */
951void _torture_stop_kthread(char *m, struct task_struct **tp)
952{
953 if (*tp == NULL)
954 return;
955 VERBOSE_TOROUT_STRING(m);
956 kthread_stop(*tp);
957 *tp = NULL;
958}
959EXPORT_SYMBOL_GPL(_torture_stop_kthread);