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1/*
2 * Common functions for in-kernel torture tests.
3 *
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.
8 *
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.
13 *
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.
17 *
18 * Copyright (C) IBM Corporation, 2014
19 *
20 * Author: Paul E. McKenney <paulmck@us.ibm.com>
21 * Based on kernel/rcu/torture.c.
22 */
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/smp.h>
31#include <linux/interrupt.h>
32#include <linux/sched.h>
33#include <linux/atomic.h>
34#include <linux/bitops.h>
35#include <linux/completion.h>
36#include <linux/moduleparam.h>
37#include <linux/percpu.h>
38#include <linux/notifier.h>
39#include <linux/reboot.h>
40#include <linux/freezer.h>
41#include <linux/cpu.h>
42#include <linux/delay.h>
43#include <linux/stat.h>
44#include <linux/slab.h>
45#include <linux/trace_clock.h>
46#include <asm/byteorder.h>
47#include <linux/torture.h>
48
49MODULE_LICENSE("GPL");
50MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
51
52static char *torture_type;
53static bool verbose;
54
55/* Mediate rmmod and system shutdown. Concurrent rmmod & shutdown illegal! */
56#define FULLSTOP_DONTSTOP 0 /* Normal operation. */
57#define FULLSTOP_SHUTDOWN 1 /* System shutdown with torture running. */
58#define FULLSTOP_RMMOD 2 /* Normal rmmod of torture. */
59static int fullstop = FULLSTOP_RMMOD;
60static DEFINE_MUTEX(fullstop_mutex);
61static int *torture_runnable;
62
63#ifdef CONFIG_HOTPLUG_CPU
64
65/*
66 * Variables for online-offline handling. Only present if CPU hotplug
67 * is enabled, otherwise does nothing.
68 */
69
70static struct task_struct *onoff_task;
71static long onoff_holdoff;
72static long onoff_interval;
73static long n_offline_attempts;
74static long n_offline_successes;
75static unsigned long sum_offline;
76static int min_offline = -1;
77static int max_offline;
78static long n_online_attempts;
79static long n_online_successes;
80static unsigned long sum_online;
81static int min_online = -1;
82static int max_online;
83
84/*
85 * Execute random CPU-hotplug operations at the interval specified
86 * by the onoff_interval.
87 */
88static int
89torture_onoff(void *arg)
90{
91 int cpu;
92 unsigned long delta;
93 int maxcpu = -1;
94 DEFINE_TORTURE_RANDOM(rand);
95 int ret;
96 unsigned long starttime;
97
98 VERBOSE_TOROUT_STRING("torture_onoff task started");
99 for_each_online_cpu(cpu)
100 maxcpu = cpu;
101 WARN_ON(maxcpu < 0);
102 if (onoff_holdoff > 0) {
103 VERBOSE_TOROUT_STRING("torture_onoff begin holdoff");
104 schedule_timeout_interruptible(onoff_holdoff);
105 VERBOSE_TOROUT_STRING("torture_onoff end holdoff");
106 }
107 while (!torture_must_stop()) {
108 cpu = (torture_random(&rand) >> 4) % (maxcpu + 1);
109 if (cpu_online(cpu) && cpu_is_hotpluggable(cpu)) {
110 if (verbose)
111 pr_alert("%s" TORTURE_FLAG
112 "torture_onoff task: offlining %d\n",
113 torture_type, cpu);
114 starttime = jiffies;
115 n_offline_attempts++;
116 ret = cpu_down(cpu);
117 if (ret) {
118 if (verbose)
119 pr_alert("%s" TORTURE_FLAG
120 "torture_onoff task: offline %d failed: errno %d\n",
121 torture_type, cpu, ret);
122 } else {
123 if (verbose)
124 pr_alert("%s" TORTURE_FLAG
125 "torture_onoff task: offlined %d\n",
126 torture_type, cpu);
127 n_offline_successes++;
128 delta = jiffies - starttime;
129 sum_offline += delta;
130 if (min_offline < 0) {
131 min_offline = delta;
132 max_offline = delta;
133 }
134 if (min_offline > delta)
135 min_offline = delta;
136 if (max_offline < delta)
137 max_offline = delta;
138 }
139 } else if (cpu_is_hotpluggable(cpu)) {
140 if (verbose)
141 pr_alert("%s" TORTURE_FLAG
142 "torture_onoff task: onlining %d\n",
143 torture_type, cpu);
144 starttime = jiffies;
145 n_online_attempts++;
146 ret = cpu_up(cpu);
147 if (ret) {
148 if (verbose)
149 pr_alert("%s" TORTURE_FLAG
150 "torture_onoff task: online %d failed: errno %d\n",
151 torture_type, cpu, ret);
152 } else {
153 if (verbose)
154 pr_alert("%s" TORTURE_FLAG
155 "torture_onoff task: onlined %d\n",
156 torture_type, cpu);
157 n_online_successes++;
158 delta = jiffies - starttime;
159 sum_online += delta;
160 if (min_online < 0) {
161 min_online = delta;
162 max_online = delta;
163 }
164 if (min_online > delta)
165 min_online = delta;
166 if (max_online < delta)
167 max_online = delta;
168 }
169 }
170 schedule_timeout_interruptible(onoff_interval);
171 }
172 torture_kthread_stopping("torture_onoff");
173 return 0;
174}
175
176#endif /* #ifdef CONFIG_HOTPLUG_CPU */
177
178/*
179 * Initiate online-offline handling.
180 */
181int torture_onoff_init(long ooholdoff, long oointerval)
182{
183 int ret = 0;
184
185#ifdef CONFIG_HOTPLUG_CPU
186 onoff_holdoff = ooholdoff;
187 onoff_interval = oointerval;
188 if (onoff_interval <= 0)
189 return 0;
190 ret = torture_create_kthread(torture_onoff, NULL, onoff_task);
191#endif /* #ifdef CONFIG_HOTPLUG_CPU */
192 return ret;
193}
194EXPORT_SYMBOL_GPL(torture_onoff_init);
195
196/*
197 * Clean up after online/offline testing.
198 */
199static void torture_onoff_cleanup(void)
200{
201#ifdef CONFIG_HOTPLUG_CPU
202 if (onoff_task == NULL)
203 return;
204 VERBOSE_TOROUT_STRING("Stopping torture_onoff task");
205 kthread_stop(onoff_task);
206 onoff_task = NULL;
207#endif /* #ifdef CONFIG_HOTPLUG_CPU */
208}
209EXPORT_SYMBOL_GPL(torture_onoff_cleanup);
210
211/*
212 * Print online/offline testing statistics.
213 */
214char *torture_onoff_stats(char *page)
215{
216#ifdef CONFIG_HOTPLUG_CPU
217 page += sprintf(page,
218 "onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ",
219 n_online_successes, n_online_attempts,
220 n_offline_successes, n_offline_attempts,
221 min_online, max_online,
222 min_offline, max_offline,
223 sum_online, sum_offline, HZ);
224#endif /* #ifdef CONFIG_HOTPLUG_CPU */
225 return page;
226}
227EXPORT_SYMBOL_GPL(torture_onoff_stats);
228
229/*
230 * Were all the online/offline operations successful?
231 */
232bool torture_onoff_failures(void)
233{
234#ifdef CONFIG_HOTPLUG_CPU
235 return n_online_successes != n_online_attempts ||
236 n_offline_successes != n_offline_attempts;
237#else /* #ifdef CONFIG_HOTPLUG_CPU */
238 return false;
239#endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
240}
241EXPORT_SYMBOL_GPL(torture_onoff_failures);
242
243#define TORTURE_RANDOM_MULT 39916801 /* prime */
244#define TORTURE_RANDOM_ADD 479001701 /* prime */
245#define TORTURE_RANDOM_REFRESH 10000
246
247/*
248 * Crude but fast random-number generator. Uses a linear congruential
249 * generator, with occasional help from cpu_clock().
250 */
251unsigned long
252torture_random(struct torture_random_state *trsp)
253{
254 if (--trsp->trs_count < 0) {
255 trsp->trs_state += (unsigned long)local_clock();
256 trsp->trs_count = TORTURE_RANDOM_REFRESH;
257 }
258 trsp->trs_state = trsp->trs_state * TORTURE_RANDOM_MULT +
259 TORTURE_RANDOM_ADD;
260 return swahw32(trsp->trs_state);
261}
262EXPORT_SYMBOL_GPL(torture_random);
263
264/*
265 * Variables for shuffling. The idea is to ensure that each CPU stays
266 * idle for an extended period to test interactions with dyntick idle,
267 * as well as interactions with any per-CPU varibles.
268 */
269struct shuffle_task {
270 struct list_head st_l;
271 struct task_struct *st_t;
272};
273
274static long shuffle_interval; /* In jiffies. */
275static struct task_struct *shuffler_task;
276static cpumask_var_t shuffle_tmp_mask;
277static int shuffle_idle_cpu; /* Force all torture tasks off this CPU */
278static struct list_head shuffle_task_list = LIST_HEAD_INIT(shuffle_task_list);
279static DEFINE_MUTEX(shuffle_task_mutex);
280
281/*
282 * Register a task to be shuffled. If there is no memory, just splat
283 * and don't bother registering.
284 */
285void torture_shuffle_task_register(struct task_struct *tp)
286{
287 struct shuffle_task *stp;
288
289 if (WARN_ON_ONCE(tp == NULL))
290 return;
291 stp = kmalloc(sizeof(*stp), GFP_KERNEL);
292 if (WARN_ON_ONCE(stp == NULL))
293 return;
294 stp->st_t = tp;
295 mutex_lock(&shuffle_task_mutex);
296 list_add(&stp->st_l, &shuffle_task_list);
297 mutex_unlock(&shuffle_task_mutex);
298}
299EXPORT_SYMBOL_GPL(torture_shuffle_task_register);
300
301/*
302 * Unregister all tasks, for example, at the end of the torture run.
303 */
304static void torture_shuffle_task_unregister_all(void)
305{
306 struct shuffle_task *stp;
307 struct shuffle_task *p;
308
309 mutex_lock(&shuffle_task_mutex);
310 list_for_each_entry_safe(stp, p, &shuffle_task_list, st_l) {
311 list_del(&stp->st_l);
312 kfree(stp);
313 }
314 mutex_unlock(&shuffle_task_mutex);
315}
316
317/* Shuffle tasks such that we allow shuffle_idle_cpu to become idle.
318 * A special case is when shuffle_idle_cpu = -1, in which case we allow
319 * the tasks to run on all CPUs.
320 */
321static void torture_shuffle_tasks(void)
322{
323 struct shuffle_task *stp;
324
325 cpumask_setall(shuffle_tmp_mask);
326 get_online_cpus();
327
328 /* No point in shuffling if there is only one online CPU (ex: UP) */
329 if (num_online_cpus() == 1) {
330 put_online_cpus();
331 return;
332 }
333
334 /* Advance to the next CPU. Upon overflow, don't idle any CPUs. */
335 shuffle_idle_cpu = cpumask_next(shuffle_idle_cpu, shuffle_tmp_mask);
336 if (shuffle_idle_cpu >= nr_cpu_ids)
337 shuffle_idle_cpu = -1;
338 if (shuffle_idle_cpu != -1) {
339 cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask);
340 if (cpumask_empty(shuffle_tmp_mask)) {
341 put_online_cpus();
342 return;
343 }
344 }
345
346 mutex_lock(&shuffle_task_mutex);
347 list_for_each_entry(stp, &shuffle_task_list, st_l)
348 set_cpus_allowed_ptr(stp->st_t, shuffle_tmp_mask);
349 mutex_unlock(&shuffle_task_mutex);
350
351 put_online_cpus();
352}
353
354/* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
355 * system to become idle at a time and cut off its timer ticks. This is meant
356 * to test the support for such tickless idle CPU in RCU.
357 */
358static int torture_shuffle(void *arg)
359{
360 VERBOSE_TOROUT_STRING("torture_shuffle task started");
361 do {
362 schedule_timeout_interruptible(shuffle_interval);
363 torture_shuffle_tasks();
364 torture_shutdown_absorb("torture_shuffle");
365 } while (!torture_must_stop());
366 torture_kthread_stopping("torture_shuffle");
367 return 0;
368}
369
370/*
371 * Start the shuffler, with shuffint in jiffies.
372 */
373int torture_shuffle_init(long shuffint)
374{
375 shuffle_interval = shuffint;
376
377 shuffle_idle_cpu = -1;
378
379 if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
380 VERBOSE_TOROUT_ERRSTRING("Failed to alloc mask");
381 return -ENOMEM;
382 }
383
384 /* Create the shuffler thread */
385 return torture_create_kthread(torture_shuffle, NULL, shuffler_task);
386}
387EXPORT_SYMBOL_GPL(torture_shuffle_init);
388
389/*
390 * Stop the shuffling.
391 */
392static void torture_shuffle_cleanup(void)
393{
394 torture_shuffle_task_unregister_all();
395 if (shuffler_task) {
396 VERBOSE_TOROUT_STRING("Stopping torture_shuffle task");
397 kthread_stop(shuffler_task);
398 free_cpumask_var(shuffle_tmp_mask);
399 }
400 shuffler_task = NULL;
401}
402EXPORT_SYMBOL_GPL(torture_shuffle_cleanup);
403
404/*
405 * Variables for auto-shutdown. This allows "lights out" torture runs
406 * to be fully scripted.
407 */
408static int shutdown_secs; /* desired test duration in seconds. */
409static struct task_struct *shutdown_task;
410static unsigned long shutdown_time; /* jiffies to system shutdown. */
411static void (*torture_shutdown_hook)(void);
412
413/*
414 * Absorb kthreads into a kernel function that won't return, so that
415 * they won't ever access module text or data again.
416 */
417void torture_shutdown_absorb(const char *title)
418{
419 while (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
420 pr_notice("torture thread %s parking due to system shutdown\n",
421 title);
422 schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
423 }
424}
425EXPORT_SYMBOL_GPL(torture_shutdown_absorb);
426
427/*
428 * Cause the torture test to shutdown the system after the test has
429 * run for the time specified by the shutdown_secs parameter.
430 */
431static int torture_shutdown(void *arg)
432{
433 long delta;
434 unsigned long jiffies_snap;
435
436 VERBOSE_TOROUT_STRING("torture_shutdown task started");
437 jiffies_snap = jiffies;
438 while (ULONG_CMP_LT(jiffies_snap, shutdown_time) &&
439 !torture_must_stop()) {
440 delta = shutdown_time - jiffies_snap;
441 if (verbose)
442 pr_alert("%s" TORTURE_FLAG
443 "torture_shutdown task: %lu jiffies remaining\n",
444 torture_type, delta);
445 schedule_timeout_interruptible(delta);
446 jiffies_snap = jiffies;
447 }
448 if (torture_must_stop()) {
449 torture_kthread_stopping("torture_shutdown");
450 return 0;
451 }
452
453 /* OK, shut down the system. */
454
455 VERBOSE_TOROUT_STRING("torture_shutdown task shutting down system");
456 shutdown_task = NULL; /* Avoid self-kill deadlock. */
457 if (torture_shutdown_hook)
458 torture_shutdown_hook();
459 else
460 VERBOSE_TOROUT_STRING("No torture_shutdown_hook(), skipping.");
461 kernel_power_off(); /* Shut down the system. */
462 return 0;
463}
464
465/*
466 * Start up the shutdown task.
467 */
468int torture_shutdown_init(int ssecs, void (*cleanup)(void))
469{
470 int ret = 0;
471
472 shutdown_secs = ssecs;
473 torture_shutdown_hook = cleanup;
474 if (shutdown_secs > 0) {
475 shutdown_time = jiffies + shutdown_secs * HZ;
476 ret = torture_create_kthread(torture_shutdown, NULL,
477 shutdown_task);
478 }
479 return ret;
480}
481EXPORT_SYMBOL_GPL(torture_shutdown_init);
482
483/*
484 * Detect and respond to a system shutdown.
485 */
486static int torture_shutdown_notify(struct notifier_block *unused1,
487 unsigned long unused2, void *unused3)
488{
489 mutex_lock(&fullstop_mutex);
490 if (ACCESS_ONCE(fullstop) == FULLSTOP_DONTSTOP) {
491 VERBOSE_TOROUT_STRING("Unscheduled system shutdown detected");
492 ACCESS_ONCE(fullstop) = FULLSTOP_SHUTDOWN;
493 } else {
494 pr_warn("Concurrent rmmod and shutdown illegal!\n");
495 }
496 mutex_unlock(&fullstop_mutex);
497 return NOTIFY_DONE;
498}
499
500static struct notifier_block torture_shutdown_nb = {
501 .notifier_call = torture_shutdown_notify,
502};
503
504/*
505 * Shut down the shutdown task. Say what??? Heh! This can happen if
506 * the torture module gets an rmmod before the shutdown time arrives. ;-)
507 */
508static void torture_shutdown_cleanup(void)
509{
510 unregister_reboot_notifier(&torture_shutdown_nb);
511 if (shutdown_task != NULL) {
512 VERBOSE_TOROUT_STRING("Stopping torture_shutdown task");
513 kthread_stop(shutdown_task);
514 }
515 shutdown_task = NULL;
516}
517
518/*
519 * Variables for stuttering, which means to periodically pause and
520 * restart testing in order to catch bugs that appear when load is
521 * suddenly applied to or removed from the system.
522 */
523static struct task_struct *stutter_task;
524static int stutter_pause_test;
525static int stutter;
526
527/*
528 * Block until the stutter interval ends. This must be called periodically
529 * by all running kthreads that need to be subject to stuttering.
530 */
531void stutter_wait(const char *title)
532{
533 while (ACCESS_ONCE(stutter_pause_test) ||
534 (torture_runnable && !ACCESS_ONCE(*torture_runnable))) {
535 if (stutter_pause_test)
536 schedule_timeout_interruptible(1);
537 else
538 schedule_timeout_interruptible(round_jiffies_relative(HZ));
539 torture_shutdown_absorb(title);
540 }
541}
542EXPORT_SYMBOL_GPL(stutter_wait);
543
544/*
545 * Cause the torture test to "stutter", starting and stopping all
546 * threads periodically.
547 */
548static int torture_stutter(void *arg)
549{
550 VERBOSE_TOROUT_STRING("torture_stutter task started");
551 do {
552 if (!torture_must_stop()) {
553 schedule_timeout_interruptible(stutter);
554 ACCESS_ONCE(stutter_pause_test) = 1;
555 }
556 if (!torture_must_stop())
557 schedule_timeout_interruptible(stutter);
558 ACCESS_ONCE(stutter_pause_test) = 0;
559 torture_shutdown_absorb("torture_stutter");
560 } while (!torture_must_stop());
561 torture_kthread_stopping("torture_stutter");
562 return 0;
563}
564
565/*
566 * Initialize and kick off the torture_stutter kthread.
567 */
568int torture_stutter_init(int s)
569{
570 int ret;
571
572 stutter = s;
573 ret = torture_create_kthread(torture_stutter, NULL, stutter_task);
574 return ret;
575}
576EXPORT_SYMBOL_GPL(torture_stutter_init);
577
578/*
579 * Cleanup after the torture_stutter kthread.
580 */
581static void torture_stutter_cleanup(void)
582{
583 if (!stutter_task)
584 return;
585 VERBOSE_TOROUT_STRING("Stopping torture_stutter task");
586 kthread_stop(stutter_task);
587 stutter_task = NULL;
588}
589
590/*
591 * Initialize torture module. Please note that this is -not- invoked via
592 * the usual module_init() mechanism, but rather by an explicit call from
593 * the client torture module. This call must be paired with a later
594 * torture_init_end().
595 *
596 * The runnable parameter points to a flag that controls whether or not
597 * the test is currently runnable. If there is no such flag, pass in NULL.
598 */
599void __init torture_init_begin(char *ttype, bool v, int *runnable)
600{
601 mutex_lock(&fullstop_mutex);
602 torture_type = ttype;
603 verbose = v;
604 torture_runnable = runnable;
605 fullstop = FULLSTOP_DONTSTOP;
606
607}
608EXPORT_SYMBOL_GPL(torture_init_begin);
609
610/*
611 * Tell the torture module that initialization is complete.
612 */
613void __init torture_init_end(void)
614{
615 mutex_unlock(&fullstop_mutex);
616 register_reboot_notifier(&torture_shutdown_nb);
617}
618EXPORT_SYMBOL_GPL(torture_init_end);
619
620/*
621 * Clean up torture module. Please note that this is -not- invoked via
622 * the usual module_exit() mechanism, but rather by an explicit call from
623 * the client torture module. Returns true if a race with system shutdown
624 * is detected, otherwise, all kthreads started by functions in this file
625 * will be shut down.
626 *
627 * This must be called before the caller starts shutting down its own
628 * kthreads.
629 */
630bool torture_cleanup(void)
631{
632 mutex_lock(&fullstop_mutex);
633 if (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
634 pr_warn("Concurrent rmmod and shutdown illegal!\n");
635 mutex_unlock(&fullstop_mutex);
636 schedule_timeout_uninterruptible(10);
637 return true;
638 }
639 ACCESS_ONCE(fullstop) = FULLSTOP_RMMOD;
640 mutex_unlock(&fullstop_mutex);
641 torture_shutdown_cleanup();
642 torture_shuffle_cleanup();
643 torture_stutter_cleanup();
644 torture_onoff_cleanup();
645 return false;
646}
647EXPORT_SYMBOL_GPL(torture_cleanup);
648
649/*
650 * Is it time for the current torture test to stop?
651 */
652bool torture_must_stop(void)
653{
654 return torture_must_stop_irq() || kthread_should_stop();
655}
656EXPORT_SYMBOL_GPL(torture_must_stop);
657
658/*
659 * Is it time for the current torture test to stop? This is the irq-safe
660 * version, hence no check for kthread_should_stop().
661 */
662bool torture_must_stop_irq(void)
663{
664 return ACCESS_ONCE(fullstop) != FULLSTOP_DONTSTOP;
665}
666EXPORT_SYMBOL_GPL(torture_must_stop_irq);
667
668/*
669 * Each kthread must wait for kthread_should_stop() before returning from
670 * its top-level function, otherwise segfaults ensue. This function
671 * prints a "stopping" message and waits for kthread_should_stop(), and
672 * should be called from all torture kthreads immediately prior to
673 * returning.
674 */
675void torture_kthread_stopping(char *title)
676{
677 if (verbose)
678 VERBOSE_TOROUT_STRING(title);
679 while (!kthread_should_stop()) {
680 torture_shutdown_absorb(title);
681 schedule_timeout_uninterruptible(1);
682 }
683}
684EXPORT_SYMBOL_GPL(torture_kthread_stopping);
685
686/*
687 * Create a generic torture kthread that is immediately runnable. If you
688 * need the kthread to be stopped so that you can do something to it before
689 * it starts, you will need to open-code your own.
690 */
691int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
692 char *f, struct task_struct **tp)
693{
694 int ret = 0;
695
696 VERBOSE_TOROUT_STRING(m);
697 *tp = kthread_run(fn, arg, s);
698 if (IS_ERR(*tp)) {
699 ret = PTR_ERR(*tp);
700 VERBOSE_TOROUT_ERRSTRING(f);
701 *tp = NULL;
702 }
703 torture_shuffle_task_register(*tp);
704 return ret;
705}
706EXPORT_SYMBOL_GPL(_torture_create_kthread);
707
708/*
709 * Stop a generic kthread, emitting a message.
710 */
711void _torture_stop_kthread(char *m, struct task_struct **tp)
712{
713 if (*tp == NULL)
714 return;
715 VERBOSE_TOROUT_STRING(m);
716 kthread_stop(*tp);
717 *tp = NULL;
718}
719EXPORT_SYMBOL_GPL(_torture_stop_kthread);
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_LICENSE("GPL");
44MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>");
45
46static bool disable_onoff_at_boot;
47module_param(disable_onoff_at_boot, bool, 0444);
48
49static bool ftrace_dump_at_shutdown;
50module_param(ftrace_dump_at_shutdown, bool, 0444);
51
52static int verbose_sleep_frequency;
53module_param(verbose_sleep_frequency, int, 0444);
54
55static int verbose_sleep_duration = 1;
56module_param(verbose_sleep_duration, int, 0444);
57
58static int random_shuffle;
59module_param(random_shuffle, int, 0444);
60
61static char *torture_type;
62static int verbose;
63
64/* Mediate rmmod and system shutdown. Concurrent rmmod & shutdown illegal! */
65#define FULLSTOP_DONTSTOP 0 /* Normal operation. */
66#define FULLSTOP_SHUTDOWN 1 /* System shutdown with torture running. */
67#define FULLSTOP_RMMOD 2 /* Normal rmmod of torture. */
68static int fullstop = FULLSTOP_RMMOD;
69static DEFINE_MUTEX(fullstop_mutex);
70
71static atomic_t verbose_sleep_counter;
72
73/*
74 * Sleep if needed from VERBOSE_TOROUT*().
75 */
76void verbose_torout_sleep(void)
77{
78 if (verbose_sleep_frequency > 0 &&
79 verbose_sleep_duration > 0 &&
80 !(atomic_inc_return(&verbose_sleep_counter) % verbose_sleep_frequency))
81 schedule_timeout_uninterruptible(verbose_sleep_duration);
82}
83EXPORT_SYMBOL_GPL(verbose_torout_sleep);
84
85/*
86 * Schedule a high-resolution-timer sleep in nanoseconds, with a 32-bit
87 * nanosecond random fuzz. This function and its friends desynchronize
88 * testing from the timer wheel.
89 */
90int torture_hrtimeout_ns(ktime_t baset_ns, u32 fuzzt_ns, const enum hrtimer_mode mode,
91 struct torture_random_state *trsp)
92{
93 ktime_t hto = baset_ns;
94
95 if (trsp)
96 hto += torture_random(trsp) % fuzzt_ns;
97 set_current_state(TASK_IDLE);
98 return schedule_hrtimeout(&hto, mode);
99}
100EXPORT_SYMBOL_GPL(torture_hrtimeout_ns);
101
102/*
103 * Schedule a high-resolution-timer sleep in microseconds, with a 32-bit
104 * nanosecond (not microsecond!) random fuzz.
105 */
106int torture_hrtimeout_us(u32 baset_us, u32 fuzzt_ns, struct torture_random_state *trsp)
107{
108 ktime_t baset_ns = baset_us * NSEC_PER_USEC;
109
110 return torture_hrtimeout_ns(baset_ns, fuzzt_ns, HRTIMER_MODE_REL, trsp);
111}
112EXPORT_SYMBOL_GPL(torture_hrtimeout_us);
113
114/*
115 * Schedule a high-resolution-timer sleep in milliseconds, with a 32-bit
116 * microsecond (not millisecond!) random fuzz.
117 */
118int torture_hrtimeout_ms(u32 baset_ms, u32 fuzzt_us, struct torture_random_state *trsp)
119{
120 ktime_t baset_ns = baset_ms * NSEC_PER_MSEC;
121 u32 fuzzt_ns;
122
123 if ((u32)~0U / NSEC_PER_USEC < fuzzt_us)
124 fuzzt_ns = (u32)~0U;
125 else
126 fuzzt_ns = fuzzt_us * NSEC_PER_USEC;
127 return torture_hrtimeout_ns(baset_ns, fuzzt_ns, HRTIMER_MODE_REL, trsp);
128}
129EXPORT_SYMBOL_GPL(torture_hrtimeout_ms);
130
131/*
132 * Schedule a high-resolution-timer sleep in jiffies, with an
133 * implied one-jiffy random fuzz. This is intended to replace calls to
134 * schedule_timeout_interruptible() and friends.
135 */
136int torture_hrtimeout_jiffies(u32 baset_j, struct torture_random_state *trsp)
137{
138 ktime_t baset_ns = jiffies_to_nsecs(baset_j);
139
140 return torture_hrtimeout_ns(baset_ns, jiffies_to_nsecs(1), HRTIMER_MODE_REL, trsp);
141}
142EXPORT_SYMBOL_GPL(torture_hrtimeout_jiffies);
143
144/*
145 * Schedule a high-resolution-timer sleep in milliseconds, with a 32-bit
146 * millisecond (not second!) random fuzz.
147 */
148int torture_hrtimeout_s(u32 baset_s, u32 fuzzt_ms, struct torture_random_state *trsp)
149{
150 ktime_t baset_ns = baset_s * NSEC_PER_SEC;
151 u32 fuzzt_ns;
152
153 if ((u32)~0U / NSEC_PER_MSEC < fuzzt_ms)
154 fuzzt_ns = (u32)~0U;
155 else
156 fuzzt_ns = fuzzt_ms * NSEC_PER_MSEC;
157 return torture_hrtimeout_ns(baset_ns, fuzzt_ns, HRTIMER_MODE_REL, trsp);
158}
159EXPORT_SYMBOL_GPL(torture_hrtimeout_s);
160
161#ifdef CONFIG_HOTPLUG_CPU
162
163/*
164 * Variables for online-offline handling. Only present if CPU hotplug
165 * is enabled, otherwise does nothing.
166 */
167
168static struct task_struct *onoff_task;
169static long onoff_holdoff;
170static long onoff_interval;
171static torture_ofl_func *onoff_f;
172static long n_offline_attempts;
173static long n_offline_successes;
174static unsigned long sum_offline;
175static int min_offline = -1;
176static int max_offline;
177static long n_online_attempts;
178static long n_online_successes;
179static unsigned long sum_online;
180static int min_online = -1;
181static int max_online;
182
183static int torture_online_cpus = NR_CPUS;
184
185/*
186 * Some torture testing leverages confusion as to the number of online
187 * CPUs. This function returns the torture-testing view of this number,
188 * which allows torture tests to load-balance appropriately.
189 */
190int torture_num_online_cpus(void)
191{
192 return READ_ONCE(torture_online_cpus);
193}
194EXPORT_SYMBOL_GPL(torture_num_online_cpus);
195
196/*
197 * Attempt to take a CPU offline. Return false if the CPU is already
198 * offline or if it is not subject to CPU-hotplug operations. The
199 * caller can detect other failures by looking at the statistics.
200 */
201bool torture_offline(int cpu, long *n_offl_attempts, long *n_offl_successes,
202 unsigned long *sum_offl, int *min_offl, int *max_offl)
203{
204 unsigned long delta;
205 int ret;
206 char *s;
207 unsigned long starttime;
208
209 if (!cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
210 return false;
211 if (num_online_cpus() <= 1)
212 return false; /* Can't offline the last CPU. */
213
214 if (verbose > 1)
215 pr_alert("%s" TORTURE_FLAG
216 "torture_onoff task: offlining %d\n",
217 torture_type, cpu);
218 starttime = jiffies;
219 (*n_offl_attempts)++;
220 ret = remove_cpu(cpu);
221 if (ret) {
222 s = "";
223 if (!rcu_inkernel_boot_has_ended() && ret == -EBUSY) {
224 // PCI probe frequently disables hotplug during boot.
225 (*n_offl_attempts)--;
226 s = " (-EBUSY forgiven during boot)";
227 }
228 if (verbose)
229 pr_alert("%s" TORTURE_FLAG
230 "torture_onoff task: offline %d failed%s: errno %d\n",
231 torture_type, cpu, s, ret);
232 } else {
233 if (verbose > 1)
234 pr_alert("%s" TORTURE_FLAG
235 "torture_onoff task: offlined %d\n",
236 torture_type, cpu);
237 if (onoff_f)
238 onoff_f();
239 (*n_offl_successes)++;
240 delta = jiffies - starttime;
241 *sum_offl += delta;
242 if (*min_offl < 0) {
243 *min_offl = delta;
244 *max_offl = delta;
245 }
246 if (*min_offl > delta)
247 *min_offl = delta;
248 if (*max_offl < delta)
249 *max_offl = delta;
250 WRITE_ONCE(torture_online_cpus, torture_online_cpus - 1);
251 WARN_ON_ONCE(torture_online_cpus <= 0);
252 }
253
254 return true;
255}
256EXPORT_SYMBOL_GPL(torture_offline);
257
258/*
259 * Attempt to bring a CPU online. Return false if the CPU is already
260 * online or if it is not subject to CPU-hotplug operations. The
261 * caller can detect other failures by looking at the statistics.
262 */
263bool torture_online(int cpu, long *n_onl_attempts, long *n_onl_successes,
264 unsigned long *sum_onl, int *min_onl, int *max_onl)
265{
266 unsigned long delta;
267 int ret;
268 char *s;
269 unsigned long starttime;
270
271 if (cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
272 return false;
273
274 if (verbose > 1)
275 pr_alert("%s" TORTURE_FLAG
276 "torture_onoff task: onlining %d\n",
277 torture_type, cpu);
278 starttime = jiffies;
279 (*n_onl_attempts)++;
280 ret = add_cpu(cpu);
281 if (ret) {
282 s = "";
283 if (!rcu_inkernel_boot_has_ended() && ret == -EBUSY) {
284 // PCI probe frequently disables hotplug during boot.
285 (*n_onl_attempts)--;
286 s = " (-EBUSY forgiven during boot)";
287 }
288 if (verbose)
289 pr_alert("%s" TORTURE_FLAG
290 "torture_onoff task: online %d failed%s: errno %d\n",
291 torture_type, cpu, s, ret);
292 } else {
293 if (verbose > 1)
294 pr_alert("%s" TORTURE_FLAG
295 "torture_onoff task: onlined %d\n",
296 torture_type, cpu);
297 (*n_onl_successes)++;
298 delta = jiffies - starttime;
299 *sum_onl += delta;
300 if (*min_onl < 0) {
301 *min_onl = delta;
302 *max_onl = delta;
303 }
304 if (*min_onl > delta)
305 *min_onl = delta;
306 if (*max_onl < delta)
307 *max_onl = delta;
308 WRITE_ONCE(torture_online_cpus, torture_online_cpus + 1);
309 }
310
311 return true;
312}
313EXPORT_SYMBOL_GPL(torture_online);
314
315/*
316 * Get everything online at the beginning and ends of tests.
317 */
318static void torture_online_all(char *phase)
319{
320 int cpu;
321 int ret;
322
323 for_each_possible_cpu(cpu) {
324 if (cpu_online(cpu))
325 continue;
326 ret = add_cpu(cpu);
327 if (ret && verbose) {
328 pr_alert("%s" TORTURE_FLAG
329 "%s: %s online %d: errno %d\n",
330 __func__, phase, torture_type, cpu, ret);
331 }
332 }
333}
334
335/*
336 * Execute random CPU-hotplug operations at the interval specified
337 * by the onoff_interval.
338 */
339static int
340torture_onoff(void *arg)
341{
342 int cpu;
343 int maxcpu = -1;
344 DEFINE_TORTURE_RANDOM(rand);
345
346 VERBOSE_TOROUT_STRING("torture_onoff task started");
347 for_each_online_cpu(cpu)
348 maxcpu = cpu;
349 WARN_ON(maxcpu < 0);
350 torture_online_all("Initial");
351 if (maxcpu == 0) {
352 VERBOSE_TOROUT_STRING("Only one CPU, so CPU-hotplug testing is disabled");
353 goto stop;
354 }
355
356 if (onoff_holdoff > 0) {
357 VERBOSE_TOROUT_STRING("torture_onoff begin holdoff");
358 torture_hrtimeout_jiffies(onoff_holdoff, &rand);
359 VERBOSE_TOROUT_STRING("torture_onoff end holdoff");
360 }
361 while (!torture_must_stop()) {
362 if (disable_onoff_at_boot && !rcu_inkernel_boot_has_ended()) {
363 torture_hrtimeout_jiffies(HZ / 10, &rand);
364 continue;
365 }
366 cpu = torture_random(&rand) % (maxcpu + 1);
367 if (!torture_offline(cpu,
368 &n_offline_attempts, &n_offline_successes,
369 &sum_offline, &min_offline, &max_offline))
370 torture_online(cpu,
371 &n_online_attempts, &n_online_successes,
372 &sum_online, &min_online, &max_online);
373 torture_hrtimeout_jiffies(onoff_interval, &rand);
374 }
375
376stop:
377 torture_kthread_stopping("torture_onoff");
378 torture_online_all("Final");
379 return 0;
380}
381
382#endif /* #ifdef CONFIG_HOTPLUG_CPU */
383
384/*
385 * Initiate online-offline handling.
386 */
387int torture_onoff_init(long ooholdoff, long oointerval, torture_ofl_func *f)
388{
389#ifdef CONFIG_HOTPLUG_CPU
390 onoff_holdoff = ooholdoff;
391 onoff_interval = oointerval;
392 onoff_f = f;
393 if (onoff_interval <= 0)
394 return 0;
395 return torture_create_kthread(torture_onoff, NULL, onoff_task);
396#else /* #ifdef CONFIG_HOTPLUG_CPU */
397 return 0;
398#endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
399}
400EXPORT_SYMBOL_GPL(torture_onoff_init);
401
402/*
403 * Clean up after online/offline testing.
404 */
405static void torture_onoff_cleanup(void)
406{
407#ifdef CONFIG_HOTPLUG_CPU
408 if (onoff_task == NULL)
409 return;
410 VERBOSE_TOROUT_STRING("Stopping torture_onoff task");
411 kthread_stop(onoff_task);
412 onoff_task = NULL;
413#endif /* #ifdef CONFIG_HOTPLUG_CPU */
414}
415
416/*
417 * Print online/offline testing statistics.
418 */
419void torture_onoff_stats(void)
420{
421#ifdef CONFIG_HOTPLUG_CPU
422 pr_cont("onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ",
423 n_online_successes, n_online_attempts,
424 n_offline_successes, n_offline_attempts,
425 min_online, max_online,
426 min_offline, max_offline,
427 sum_online, sum_offline, HZ);
428#endif /* #ifdef CONFIG_HOTPLUG_CPU */
429}
430EXPORT_SYMBOL_GPL(torture_onoff_stats);
431
432/*
433 * Were all the online/offline operations successful?
434 */
435bool torture_onoff_failures(void)
436{
437#ifdef CONFIG_HOTPLUG_CPU
438 return n_online_successes != n_online_attempts ||
439 n_offline_successes != n_offline_attempts;
440#else /* #ifdef CONFIG_HOTPLUG_CPU */
441 return false;
442#endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
443}
444EXPORT_SYMBOL_GPL(torture_onoff_failures);
445
446#define TORTURE_RANDOM_MULT 39916801 /* prime */
447#define TORTURE_RANDOM_ADD 479001701 /* prime */
448#define TORTURE_RANDOM_REFRESH 10000
449
450/*
451 * Crude but fast random-number generator. Uses a linear congruential
452 * generator, with occasional help from cpu_clock().
453 */
454unsigned long
455torture_random(struct torture_random_state *trsp)
456{
457 if (--trsp->trs_count < 0) {
458 trsp->trs_state += (unsigned long)local_clock() + raw_smp_processor_id();
459 trsp->trs_count = TORTURE_RANDOM_REFRESH;
460 }
461 trsp->trs_state = trsp->trs_state * TORTURE_RANDOM_MULT +
462 TORTURE_RANDOM_ADD;
463 return swahw32(trsp->trs_state);
464}
465EXPORT_SYMBOL_GPL(torture_random);
466
467/*
468 * Variables for shuffling. The idea is to ensure that each CPU stays
469 * idle for an extended period to test interactions with dyntick idle,
470 * as well as interactions with any per-CPU variables.
471 */
472struct shuffle_task {
473 struct list_head st_l;
474 struct task_struct *st_t;
475};
476
477static long shuffle_interval; /* In jiffies. */
478static struct task_struct *shuffler_task;
479static cpumask_var_t shuffle_tmp_mask;
480static int shuffle_idle_cpu; /* Force all torture tasks off this CPU */
481static struct list_head shuffle_task_list = LIST_HEAD_INIT(shuffle_task_list);
482static DEFINE_MUTEX(shuffle_task_mutex);
483
484/*
485 * Register a task to be shuffled. If there is no memory, just splat
486 * and don't bother registering.
487 */
488void torture_shuffle_task_register(struct task_struct *tp)
489{
490 struct shuffle_task *stp;
491
492 if (WARN_ON_ONCE(tp == NULL))
493 return;
494 stp = kmalloc(sizeof(*stp), GFP_KERNEL);
495 if (WARN_ON_ONCE(stp == NULL))
496 return;
497 stp->st_t = tp;
498 mutex_lock(&shuffle_task_mutex);
499 list_add(&stp->st_l, &shuffle_task_list);
500 mutex_unlock(&shuffle_task_mutex);
501}
502EXPORT_SYMBOL_GPL(torture_shuffle_task_register);
503
504/*
505 * Unregister all tasks, for example, at the end of the torture run.
506 */
507static void torture_shuffle_task_unregister_all(void)
508{
509 struct shuffle_task *stp;
510 struct shuffle_task *p;
511
512 mutex_lock(&shuffle_task_mutex);
513 list_for_each_entry_safe(stp, p, &shuffle_task_list, st_l) {
514 list_del(&stp->st_l);
515 kfree(stp);
516 }
517 mutex_unlock(&shuffle_task_mutex);
518}
519
520/* Shuffle tasks such that we allow shuffle_idle_cpu to become idle.
521 * A special case is when shuffle_idle_cpu = -1, in which case we allow
522 * the tasks to run on all CPUs.
523 */
524static void torture_shuffle_tasks(struct torture_random_state *trp)
525{
526 struct shuffle_task *stp;
527
528 cpumask_setall(shuffle_tmp_mask);
529 cpus_read_lock();
530
531 /* No point in shuffling if there is only one online CPU (ex: UP) */
532 if (num_online_cpus() == 1) {
533 cpus_read_unlock();
534 return;
535 }
536
537 /* Advance to the next CPU. Upon overflow, don't idle any CPUs. */
538 shuffle_idle_cpu = cpumask_next(shuffle_idle_cpu, shuffle_tmp_mask);
539 if (shuffle_idle_cpu >= nr_cpu_ids)
540 shuffle_idle_cpu = -1;
541 else
542 cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask);
543
544 mutex_lock(&shuffle_task_mutex);
545 list_for_each_entry(stp, &shuffle_task_list, st_l) {
546 if (!random_shuffle || torture_random(trp) & 0x1)
547 set_cpus_allowed_ptr(stp->st_t, shuffle_tmp_mask);
548 }
549 mutex_unlock(&shuffle_task_mutex);
550
551 cpus_read_unlock();
552}
553
554/* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
555 * system to become idle at a time and cut off its timer ticks. This is meant
556 * to test the support for such tickless idle CPU in RCU.
557 */
558static int torture_shuffle(void *arg)
559{
560 DEFINE_TORTURE_RANDOM(rand);
561
562 VERBOSE_TOROUT_STRING("torture_shuffle task started");
563 do {
564 torture_hrtimeout_jiffies(shuffle_interval, &rand);
565 torture_shuffle_tasks(&rand);
566 torture_shutdown_absorb("torture_shuffle");
567 } while (!torture_must_stop());
568 torture_kthread_stopping("torture_shuffle");
569 return 0;
570}
571
572/*
573 * Start the shuffler, with shuffint in jiffies.
574 */
575int torture_shuffle_init(long shuffint)
576{
577 shuffle_interval = shuffint;
578
579 shuffle_idle_cpu = -1;
580
581 if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
582 TOROUT_ERRSTRING("Failed to alloc mask");
583 return -ENOMEM;
584 }
585
586 /* Create the shuffler thread */
587 return torture_create_kthread(torture_shuffle, NULL, shuffler_task);
588}
589EXPORT_SYMBOL_GPL(torture_shuffle_init);
590
591/*
592 * Stop the shuffling.
593 */
594static void torture_shuffle_cleanup(void)
595{
596 torture_shuffle_task_unregister_all();
597 if (shuffler_task) {
598 VERBOSE_TOROUT_STRING("Stopping torture_shuffle task");
599 kthread_stop(shuffler_task);
600 free_cpumask_var(shuffle_tmp_mask);
601 }
602 shuffler_task = NULL;
603}
604
605/*
606 * Variables for auto-shutdown. This allows "lights out" torture runs
607 * to be fully scripted.
608 */
609static struct task_struct *shutdown_task;
610static ktime_t shutdown_time; /* time to system shutdown. */
611static void (*torture_shutdown_hook)(void);
612
613/*
614 * Absorb kthreads into a kernel function that won't return, so that
615 * they won't ever access module text or data again.
616 */
617void torture_shutdown_absorb(const char *title)
618{
619 while (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
620 pr_notice("torture thread %s parking due to system shutdown\n",
621 title);
622 schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
623 }
624}
625EXPORT_SYMBOL_GPL(torture_shutdown_absorb);
626
627/*
628 * Cause the torture test to shutdown the system after the test has
629 * run for the time specified by the shutdown_secs parameter.
630 */
631static int torture_shutdown(void *arg)
632{
633 ktime_t ktime_snap;
634
635 VERBOSE_TOROUT_STRING("torture_shutdown task started");
636 ktime_snap = ktime_get();
637 while (ktime_before(ktime_snap, shutdown_time) &&
638 !torture_must_stop()) {
639 if (verbose)
640 pr_alert("%s" TORTURE_FLAG
641 "torture_shutdown task: %llu ms remaining\n",
642 torture_type,
643 ktime_ms_delta(shutdown_time, ktime_snap));
644 set_current_state(TASK_INTERRUPTIBLE);
645 schedule_hrtimeout(&shutdown_time, HRTIMER_MODE_ABS);
646 ktime_snap = ktime_get();
647 }
648 if (torture_must_stop()) {
649 torture_kthread_stopping("torture_shutdown");
650 return 0;
651 }
652
653 /* OK, shut down the system. */
654
655 VERBOSE_TOROUT_STRING("torture_shutdown task shutting down system");
656 shutdown_task = NULL; /* Avoid self-kill deadlock. */
657 if (torture_shutdown_hook)
658 torture_shutdown_hook();
659 else
660 VERBOSE_TOROUT_STRING("No torture_shutdown_hook(), skipping.");
661 if (ftrace_dump_at_shutdown)
662 rcu_ftrace_dump(DUMP_ALL);
663 kernel_power_off(); /* Shut down the system. */
664 return 0;
665}
666
667/*
668 * Start up the shutdown task.
669 */
670int torture_shutdown_init(int ssecs, void (*cleanup)(void))
671{
672 torture_shutdown_hook = cleanup;
673 if (ssecs > 0) {
674 shutdown_time = ktime_add(ktime_get(), ktime_set(ssecs, 0));
675 return torture_create_kthread(torture_shutdown, NULL,
676 shutdown_task);
677 }
678 return 0;
679}
680EXPORT_SYMBOL_GPL(torture_shutdown_init);
681
682/*
683 * Detect and respond to a system shutdown.
684 */
685static int torture_shutdown_notify(struct notifier_block *unused1,
686 unsigned long unused2, void *unused3)
687{
688 mutex_lock(&fullstop_mutex);
689 if (READ_ONCE(fullstop) == FULLSTOP_DONTSTOP) {
690 VERBOSE_TOROUT_STRING("Unscheduled system shutdown detected");
691 WRITE_ONCE(fullstop, FULLSTOP_SHUTDOWN);
692 } else {
693 pr_warn("Concurrent rmmod and shutdown illegal!\n");
694 }
695 mutex_unlock(&fullstop_mutex);
696 return NOTIFY_DONE;
697}
698
699static struct notifier_block torture_shutdown_nb = {
700 .notifier_call = torture_shutdown_notify,
701};
702
703/*
704 * Shut down the shutdown task. Say what??? Heh! This can happen if
705 * the torture module gets an rmmod before the shutdown time arrives. ;-)
706 */
707static void torture_shutdown_cleanup(void)
708{
709 unregister_reboot_notifier(&torture_shutdown_nb);
710 if (shutdown_task != NULL) {
711 VERBOSE_TOROUT_STRING("Stopping torture_shutdown task");
712 kthread_stop(shutdown_task);
713 }
714 shutdown_task = NULL;
715}
716
717/*
718 * Variables for stuttering, which means to periodically pause and
719 * restart testing in order to catch bugs that appear when load is
720 * suddenly applied to or removed from the system.
721 */
722static struct task_struct *stutter_task;
723static ktime_t stutter_till_abs_time;
724static int stutter;
725static int stutter_gap;
726
727/*
728 * Block until the stutter interval ends. This must be called periodically
729 * by all running kthreads that need to be subject to stuttering.
730 */
731bool stutter_wait(const char *title)
732{
733 bool ret = false;
734 ktime_t till_ns;
735
736 cond_resched_tasks_rcu_qs();
737 till_ns = READ_ONCE(stutter_till_abs_time);
738 if (till_ns && ktime_before(ktime_get(), till_ns)) {
739 torture_hrtimeout_ns(till_ns, 0, HRTIMER_MODE_ABS, NULL);
740 ret = true;
741 }
742 torture_shutdown_absorb(title);
743 return ret;
744}
745EXPORT_SYMBOL_GPL(stutter_wait);
746
747/*
748 * Cause the torture test to "stutter", starting and stopping all
749 * threads periodically.
750 */
751static int torture_stutter(void *arg)
752{
753 ktime_t till_ns;
754
755 VERBOSE_TOROUT_STRING("torture_stutter task started");
756 do {
757 if (!torture_must_stop() && stutter > 1) {
758 till_ns = ktime_add_ns(ktime_get(),
759 jiffies_to_nsecs(stutter));
760 WRITE_ONCE(stutter_till_abs_time, till_ns);
761 torture_hrtimeout_jiffies(stutter - 1, NULL);
762 }
763 if (!torture_must_stop())
764 torture_hrtimeout_jiffies(stutter_gap, NULL);
765 torture_shutdown_absorb("torture_stutter");
766 } while (!torture_must_stop());
767 torture_kthread_stopping("torture_stutter");
768 return 0;
769}
770
771/*
772 * Initialize and kick off the torture_stutter kthread.
773 */
774int torture_stutter_init(const int s, const int sgap)
775{
776 stutter = s;
777 stutter_gap = sgap;
778 return torture_create_kthread(torture_stutter, NULL, stutter_task);
779}
780EXPORT_SYMBOL_GPL(torture_stutter_init);
781
782/*
783 * Cleanup after the torture_stutter kthread.
784 */
785static void torture_stutter_cleanup(void)
786{
787 if (!stutter_task)
788 return;
789 VERBOSE_TOROUT_STRING("Stopping torture_stutter task");
790 kthread_stop(stutter_task);
791 stutter_task = NULL;
792}
793
794static void
795torture_print_module_parms(void)
796{
797 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",
798 torture_type, disable_onoff_at_boot, ftrace_dump_at_shutdown, verbose_sleep_frequency, verbose_sleep_duration, random_shuffle);
799}
800
801/*
802 * Initialize torture module. Please note that this is -not- invoked via
803 * the usual module_init() mechanism, but rather by an explicit call from
804 * the client torture module. This call must be paired with a later
805 * torture_init_end().
806 *
807 * The runnable parameter points to a flag that controls whether or not
808 * the test is currently runnable. If there is no such flag, pass in NULL.
809 */
810bool torture_init_begin(char *ttype, int v)
811{
812 mutex_lock(&fullstop_mutex);
813 if (torture_type != NULL) {
814 pr_alert("%s: Refusing %s init: %s running.\n",
815 __func__, ttype, torture_type);
816 pr_alert("%s: One torture test at a time!\n", __func__);
817 mutex_unlock(&fullstop_mutex);
818 return false;
819 }
820 torture_type = ttype;
821 verbose = v;
822 fullstop = FULLSTOP_DONTSTOP;
823 torture_print_module_parms();
824 return true;
825}
826EXPORT_SYMBOL_GPL(torture_init_begin);
827
828/*
829 * Tell the torture module that initialization is complete.
830 */
831void torture_init_end(void)
832{
833 mutex_unlock(&fullstop_mutex);
834 register_reboot_notifier(&torture_shutdown_nb);
835}
836EXPORT_SYMBOL_GPL(torture_init_end);
837
838/*
839 * Clean up torture module. Please note that this is -not- invoked via
840 * the usual module_exit() mechanism, but rather by an explicit call from
841 * the client torture module. Returns true if a race with system shutdown
842 * is detected, otherwise, all kthreads started by functions in this file
843 * will be shut down.
844 *
845 * This must be called before the caller starts shutting down its own
846 * kthreads.
847 *
848 * Both torture_cleanup_begin() and torture_cleanup_end() must be paired,
849 * in order to correctly perform the cleanup. They are separated because
850 * threads can still need to reference the torture_type type, thus nullify
851 * only after completing all other relevant calls.
852 */
853bool torture_cleanup_begin(void)
854{
855 mutex_lock(&fullstop_mutex);
856 if (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
857 pr_warn("Concurrent rmmod and shutdown illegal!\n");
858 mutex_unlock(&fullstop_mutex);
859 schedule_timeout_uninterruptible(10);
860 return true;
861 }
862 WRITE_ONCE(fullstop, FULLSTOP_RMMOD);
863 mutex_unlock(&fullstop_mutex);
864 torture_shutdown_cleanup();
865 torture_shuffle_cleanup();
866 torture_stutter_cleanup();
867 torture_onoff_cleanup();
868 return false;
869}
870EXPORT_SYMBOL_GPL(torture_cleanup_begin);
871
872void torture_cleanup_end(void)
873{
874 mutex_lock(&fullstop_mutex);
875 torture_type = NULL;
876 mutex_unlock(&fullstop_mutex);
877}
878EXPORT_SYMBOL_GPL(torture_cleanup_end);
879
880/*
881 * Is it time for the current torture test to stop?
882 */
883bool torture_must_stop(void)
884{
885 return torture_must_stop_irq() || kthread_should_stop();
886}
887EXPORT_SYMBOL_GPL(torture_must_stop);
888
889/*
890 * Is it time for the current torture test to stop? This is the irq-safe
891 * version, hence no check for kthread_should_stop().
892 */
893bool torture_must_stop_irq(void)
894{
895 return READ_ONCE(fullstop) != FULLSTOP_DONTSTOP;
896}
897EXPORT_SYMBOL_GPL(torture_must_stop_irq);
898
899/*
900 * Each kthread must wait for kthread_should_stop() before returning from
901 * its top-level function, otherwise segfaults ensue. This function
902 * prints a "stopping" message and waits for kthread_should_stop(), and
903 * should be called from all torture kthreads immediately prior to
904 * returning.
905 */
906void torture_kthread_stopping(char *title)
907{
908 char buf[128];
909
910 snprintf(buf, sizeof(buf), "%s is stopping", title);
911 VERBOSE_TOROUT_STRING(buf);
912 while (!kthread_should_stop()) {
913 torture_shutdown_absorb(title);
914 schedule_timeout_uninterruptible(HZ / 20);
915 }
916}
917EXPORT_SYMBOL_GPL(torture_kthread_stopping);
918
919/*
920 * Create a generic torture kthread that is immediately runnable. If you
921 * need the kthread to be stopped so that you can do something to it before
922 * it starts, you will need to open-code your own.
923 */
924int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
925 char *f, struct task_struct **tp, void (*cbf)(struct task_struct *tp))
926{
927 int ret = 0;
928
929 VERBOSE_TOROUT_STRING(m);
930 *tp = kthread_create(fn, arg, "%s", s);
931 if (IS_ERR(*tp)) {
932 ret = PTR_ERR(*tp);
933 TOROUT_ERRSTRING(f);
934 *tp = NULL;
935 return ret;
936 }
937
938 if (cbf)
939 cbf(*tp);
940
941 wake_up_process(*tp); // Process is sleeping, so ordering provided.
942 torture_shuffle_task_register(*tp);
943 return ret;
944}
945EXPORT_SYMBOL_GPL(_torture_create_kthread);
946
947/*
948 * Stop a generic kthread, emitting a message.
949 */
950void _torture_stop_kthread(char *m, struct task_struct **tp)
951{
952 if (*tp == NULL)
953 return;
954 VERBOSE_TOROUT_STRING(m);
955 kthread_stop(*tp);
956 *tp = NULL;
957}
958EXPORT_SYMBOL_GPL(_torture_stop_kthread);