Linux Audio

Check our new training course

Loading...
v4.17
 
  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/sched/clock.h>
 34#include <linux/atomic.h>
 35#include <linux/bitops.h>
 36#include <linux/completion.h>
 37#include <linux/moduleparam.h>
 38#include <linux/percpu.h>
 39#include <linux/notifier.h>
 40#include <linux/reboot.h>
 41#include <linux/freezer.h>
 42#include <linux/cpu.h>
 43#include <linux/delay.h>
 44#include <linux/stat.h>
 45#include <linux/slab.h>
 46#include <linux/trace_clock.h>
 47#include <linux/ktime.h>
 48#include <asm/byteorder.h>
 49#include <linux/torture.h>
 
 50#include "rcu/rcu.h"
 51
 52MODULE_LICENSE("GPL");
 53MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 54
 55static char *torture_type;
 56static bool verbose;
 57
 58/* Mediate rmmod and system shutdown.  Concurrent rmmod & shutdown illegal! */
 59#define FULLSTOP_DONTSTOP 0	/* Normal operation. */
 60#define FULLSTOP_SHUTDOWN 1	/* System shutdown with torture running. */
 61#define FULLSTOP_RMMOD    2	/* Normal rmmod of torture. */
 62static int fullstop = FULLSTOP_RMMOD;
 63static DEFINE_MUTEX(fullstop_mutex);
 64
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 65#ifdef CONFIG_HOTPLUG_CPU
 66
 67/*
 68 * Variables for online-offline handling.  Only present if CPU hotplug
 69 * is enabled, otherwise does nothing.
 70 */
 71
 72static struct task_struct *onoff_task;
 73static long onoff_holdoff;
 74static long onoff_interval;
 
 75static long n_offline_attempts;
 76static long n_offline_successes;
 77static unsigned long sum_offline;
 78static int min_offline = -1;
 79static int max_offline;
 80static long n_online_attempts;
 81static long n_online_successes;
 82static unsigned long sum_online;
 83static int min_online = -1;
 84static int max_online;
 85
 
 
 
 
 
 
 
 
 
 
 
 
 
 86/*
 87 * Attempt to take a CPU offline.  Return false if the CPU is already
 88 * offline or if it is not subject to CPU-hotplug operations.  The
 89 * caller can detect other failures by looking at the statistics.
 90 */
 91bool torture_offline(int cpu, long *n_offl_attempts, long *n_offl_successes,
 92		     unsigned long *sum_offl, int *min_offl, int *max_offl)
 93{
 94	unsigned long delta;
 95	int ret;
 
 96	unsigned long starttime;
 97
 98	if (!cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
 99		return false;
 
 
100
101	if (verbose)
102		pr_alert("%s" TORTURE_FLAG
103			 "torture_onoff task: offlining %d\n",
104			 torture_type, cpu);
105	starttime = jiffies;
106	(*n_offl_attempts)++;
107	ret = cpu_down(cpu);
108	if (ret) {
 
 
 
 
 
 
109		if (verbose)
110			pr_alert("%s" TORTURE_FLAG
111				 "torture_onoff task: offline %d failed: errno %d\n",
112				 torture_type, cpu, ret);
113	} else {
114		if (verbose)
115			pr_alert("%s" TORTURE_FLAG
116				 "torture_onoff task: offlined %d\n",
117				 torture_type, cpu);
 
 
118		(*n_offl_successes)++;
119		delta = jiffies - starttime;
120		*sum_offl += delta;
121		if (*min_offl < 0) {
122			*min_offl = delta;
123			*max_offl = delta;
124		}
125		if (*min_offl > delta)
126			*min_offl = delta;
127		if (*max_offl < delta)
128			*max_offl = delta;
 
 
129	}
130
131	return true;
132}
133EXPORT_SYMBOL_GPL(torture_offline);
134
135/*
136 * Attempt to bring a CPU online.  Return false if the CPU is already
137 * online or if it is not subject to CPU-hotplug operations.  The
138 * caller can detect other failures by looking at the statistics.
139 */
140bool torture_online(int cpu, long *n_onl_attempts, long *n_onl_successes,
141		    unsigned long *sum_onl, int *min_onl, int *max_onl)
142{
143	unsigned long delta;
144	int ret;
 
145	unsigned long starttime;
146
147	if (cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
148		return false;
149
150	if (verbose)
151		pr_alert("%s" TORTURE_FLAG
152			 "torture_onoff task: onlining %d\n",
153			 torture_type, cpu);
154	starttime = jiffies;
155	(*n_onl_attempts)++;
156	ret = cpu_up(cpu);
157	if (ret) {
 
 
 
 
 
 
158		if (verbose)
159			pr_alert("%s" TORTURE_FLAG
160				 "torture_onoff task: online %d failed: errno %d\n",
161				 torture_type, cpu, ret);
162	} else {
163		if (verbose)
164			pr_alert("%s" TORTURE_FLAG
165				 "torture_onoff task: onlined %d\n",
166				 torture_type, cpu);
167		(*n_onl_successes)++;
168		delta = jiffies - starttime;
169		*sum_onl += delta;
170		if (*min_onl < 0) {
171			*min_onl = delta;
172			*max_onl = delta;
173		}
174		if (*min_onl > delta)
175			*min_onl = delta;
176		if (*max_onl < delta)
177			*max_onl = delta;
 
178	}
179
180	return true;
181}
182EXPORT_SYMBOL_GPL(torture_online);
183
184/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
185 * Execute random CPU-hotplug operations at the interval specified
186 * by the onoff_interval.
187 */
188static int
189torture_onoff(void *arg)
190{
191	int cpu;
192	int maxcpu = -1;
193	DEFINE_TORTURE_RANDOM(rand);
194
195	VERBOSE_TOROUT_STRING("torture_onoff task started");
196	for_each_online_cpu(cpu)
197		maxcpu = cpu;
198	WARN_ON(maxcpu < 0);
199
200	if (maxcpu == 0) {
201		VERBOSE_TOROUT_STRING("Only one CPU, so CPU-hotplug testing is disabled");
202		goto stop;
203	}
204
205	if (onoff_holdoff > 0) {
206		VERBOSE_TOROUT_STRING("torture_onoff begin holdoff");
207		schedule_timeout_interruptible(onoff_holdoff);
208		VERBOSE_TOROUT_STRING("torture_onoff end holdoff");
209	}
210	while (!torture_must_stop()) {
211		cpu = (torture_random(&rand) >> 4) % (maxcpu + 1);
 
 
 
 
212		if (!torture_offline(cpu,
213				     &n_offline_attempts, &n_offline_successes,
214				     &sum_offline, &min_offline, &max_offline))
215			torture_online(cpu,
216				       &n_online_attempts, &n_online_successes,
217				       &sum_online, &min_online, &max_online);
218		schedule_timeout_interruptible(onoff_interval);
219	}
220
221stop:
222	torture_kthread_stopping("torture_onoff");
 
223	return 0;
224}
225
226#endif /* #ifdef CONFIG_HOTPLUG_CPU */
227
228/*
229 * Initiate online-offline handling.
230 */
231int torture_onoff_init(long ooholdoff, long oointerval)
232{
233	int ret = 0;
234
235#ifdef CONFIG_HOTPLUG_CPU
236	onoff_holdoff = ooholdoff;
237	onoff_interval = oointerval;
 
238	if (onoff_interval <= 0)
239		return 0;
240	ret = torture_create_kthread(torture_onoff, NULL, onoff_task);
241#endif /* #ifdef CONFIG_HOTPLUG_CPU */
242	return ret;
 
243}
244EXPORT_SYMBOL_GPL(torture_onoff_init);
245
246/*
247 * Clean up after online/offline testing.
248 */
249static void torture_onoff_cleanup(void)
250{
251#ifdef CONFIG_HOTPLUG_CPU
252	if (onoff_task == NULL)
253		return;
254	VERBOSE_TOROUT_STRING("Stopping torture_onoff task");
255	kthread_stop(onoff_task);
256	onoff_task = NULL;
257#endif /* #ifdef CONFIG_HOTPLUG_CPU */
258}
259EXPORT_SYMBOL_GPL(torture_onoff_cleanup);
260
261/*
262 * Print online/offline testing statistics.
263 */
264void torture_onoff_stats(void)
265{
266#ifdef CONFIG_HOTPLUG_CPU
267	pr_cont("onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ",
268		n_online_successes, n_online_attempts,
269		n_offline_successes, n_offline_attempts,
270		min_online, max_online,
271		min_offline, max_offline,
272		sum_online, sum_offline, HZ);
273#endif /* #ifdef CONFIG_HOTPLUG_CPU */
274}
275EXPORT_SYMBOL_GPL(torture_onoff_stats);
276
277/*
278 * Were all the online/offline operations successful?
279 */
280bool torture_onoff_failures(void)
281{
282#ifdef CONFIG_HOTPLUG_CPU
283	return n_online_successes != n_online_attempts ||
284	       n_offline_successes != n_offline_attempts;
285#else /* #ifdef CONFIG_HOTPLUG_CPU */
286	return false;
287#endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
288}
289EXPORT_SYMBOL_GPL(torture_onoff_failures);
290
291#define TORTURE_RANDOM_MULT	39916801  /* prime */
292#define TORTURE_RANDOM_ADD	479001701 /* prime */
293#define TORTURE_RANDOM_REFRESH	10000
294
295/*
296 * Crude but fast random-number generator.  Uses a linear congruential
297 * generator, with occasional help from cpu_clock().
298 */
299unsigned long
300torture_random(struct torture_random_state *trsp)
301{
302	if (--trsp->trs_count < 0) {
303		trsp->trs_state += (unsigned long)local_clock();
304		trsp->trs_count = TORTURE_RANDOM_REFRESH;
305	}
306	trsp->trs_state = trsp->trs_state * TORTURE_RANDOM_MULT +
307		TORTURE_RANDOM_ADD;
308	return swahw32(trsp->trs_state);
309}
310EXPORT_SYMBOL_GPL(torture_random);
311
312/*
313 * Variables for shuffling.  The idea is to ensure that each CPU stays
314 * idle for an extended period to test interactions with dyntick idle,
315 * as well as interactions with any per-CPU variables.
316 */
317struct shuffle_task {
318	struct list_head st_l;
319	struct task_struct *st_t;
320};
321
322static long shuffle_interval;	/* In jiffies. */
323static struct task_struct *shuffler_task;
324static cpumask_var_t shuffle_tmp_mask;
325static int shuffle_idle_cpu;	/* Force all torture tasks off this CPU */
326static struct list_head shuffle_task_list = LIST_HEAD_INIT(shuffle_task_list);
327static DEFINE_MUTEX(shuffle_task_mutex);
328
329/*
330 * Register a task to be shuffled.  If there is no memory, just splat
331 * and don't bother registering.
332 */
333void torture_shuffle_task_register(struct task_struct *tp)
334{
335	struct shuffle_task *stp;
336
337	if (WARN_ON_ONCE(tp == NULL))
338		return;
339	stp = kmalloc(sizeof(*stp), GFP_KERNEL);
340	if (WARN_ON_ONCE(stp == NULL))
341		return;
342	stp->st_t = tp;
343	mutex_lock(&shuffle_task_mutex);
344	list_add(&stp->st_l, &shuffle_task_list);
345	mutex_unlock(&shuffle_task_mutex);
346}
347EXPORT_SYMBOL_GPL(torture_shuffle_task_register);
348
349/*
350 * Unregister all tasks, for example, at the end of the torture run.
351 */
352static void torture_shuffle_task_unregister_all(void)
353{
354	struct shuffle_task *stp;
355	struct shuffle_task *p;
356
357	mutex_lock(&shuffle_task_mutex);
358	list_for_each_entry_safe(stp, p, &shuffle_task_list, st_l) {
359		list_del(&stp->st_l);
360		kfree(stp);
361	}
362	mutex_unlock(&shuffle_task_mutex);
363}
364
365/* Shuffle tasks such that we allow shuffle_idle_cpu to become idle.
366 * A special case is when shuffle_idle_cpu = -1, in which case we allow
367 * the tasks to run on all CPUs.
368 */
369static void torture_shuffle_tasks(void)
370{
371	struct shuffle_task *stp;
372
373	cpumask_setall(shuffle_tmp_mask);
374	get_online_cpus();
375
376	/* No point in shuffling if there is only one online CPU (ex: UP) */
377	if (num_online_cpus() == 1) {
378		put_online_cpus();
379		return;
380	}
381
382	/* Advance to the next CPU.  Upon overflow, don't idle any CPUs. */
383	shuffle_idle_cpu = cpumask_next(shuffle_idle_cpu, shuffle_tmp_mask);
384	if (shuffle_idle_cpu >= nr_cpu_ids)
385		shuffle_idle_cpu = -1;
386	else
387		cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask);
388
389	mutex_lock(&shuffle_task_mutex);
390	list_for_each_entry(stp, &shuffle_task_list, st_l)
391		set_cpus_allowed_ptr(stp->st_t, shuffle_tmp_mask);
 
 
392	mutex_unlock(&shuffle_task_mutex);
393
394	put_online_cpus();
395}
396
397/* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
398 * system to become idle at a time and cut off its timer ticks. This is meant
399 * to test the support for such tickless idle CPU in RCU.
400 */
401static int torture_shuffle(void *arg)
402{
 
 
403	VERBOSE_TOROUT_STRING("torture_shuffle task started");
404	do {
405		schedule_timeout_interruptible(shuffle_interval);
406		torture_shuffle_tasks();
407		torture_shutdown_absorb("torture_shuffle");
408	} while (!torture_must_stop());
409	torture_kthread_stopping("torture_shuffle");
410	return 0;
411}
412
413/*
414 * Start the shuffler, with shuffint in jiffies.
415 */
416int torture_shuffle_init(long shuffint)
417{
418	shuffle_interval = shuffint;
419
420	shuffle_idle_cpu = -1;
421
422	if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
423		VERBOSE_TOROUT_ERRSTRING("Failed to alloc mask");
424		return -ENOMEM;
425	}
426
427	/* Create the shuffler thread */
428	return torture_create_kthread(torture_shuffle, NULL, shuffler_task);
429}
430EXPORT_SYMBOL_GPL(torture_shuffle_init);
431
432/*
433 * Stop the shuffling.
434 */
435static void torture_shuffle_cleanup(void)
436{
437	torture_shuffle_task_unregister_all();
438	if (shuffler_task) {
439		VERBOSE_TOROUT_STRING("Stopping torture_shuffle task");
440		kthread_stop(shuffler_task);
441		free_cpumask_var(shuffle_tmp_mask);
442	}
443	shuffler_task = NULL;
444}
445EXPORT_SYMBOL_GPL(torture_shuffle_cleanup);
446
447/*
448 * Variables for auto-shutdown.  This allows "lights out" torture runs
449 * to be fully scripted.
450 */
451static struct task_struct *shutdown_task;
452static ktime_t shutdown_time;		/* time to system shutdown. */
453static void (*torture_shutdown_hook)(void);
454
455/*
456 * Absorb kthreads into a kernel function that won't return, so that
457 * they won't ever access module text or data again.
458 */
459void torture_shutdown_absorb(const char *title)
460{
461	while (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
462		pr_notice("torture thread %s parking due to system shutdown\n",
463			  title);
464		schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
465	}
466}
467EXPORT_SYMBOL_GPL(torture_shutdown_absorb);
468
469/*
470 * Cause the torture test to shutdown the system after the test has
471 * run for the time specified by the shutdown_secs parameter.
472 */
473static int torture_shutdown(void *arg)
474{
475	ktime_t ktime_snap;
476
477	VERBOSE_TOROUT_STRING("torture_shutdown task started");
478	ktime_snap = ktime_get();
479	while (ktime_before(ktime_snap, shutdown_time) &&
480	       !torture_must_stop()) {
481		if (verbose)
482			pr_alert("%s" TORTURE_FLAG
483				 "torture_shutdown task: %llu ms remaining\n",
484				 torture_type,
485				 ktime_ms_delta(shutdown_time, ktime_snap));
486		set_current_state(TASK_INTERRUPTIBLE);
487		schedule_hrtimeout(&shutdown_time, HRTIMER_MODE_ABS);
488		ktime_snap = ktime_get();
489	}
490	if (torture_must_stop()) {
491		torture_kthread_stopping("torture_shutdown");
492		return 0;
493	}
494
495	/* OK, shut down the system. */
496
497	VERBOSE_TOROUT_STRING("torture_shutdown task shutting down system");
498	shutdown_task = NULL;	/* Avoid self-kill deadlock. */
499	if (torture_shutdown_hook)
500		torture_shutdown_hook();
501	else
502		VERBOSE_TOROUT_STRING("No torture_shutdown_hook(), skipping.");
503	rcu_ftrace_dump(DUMP_ALL);
 
504	kernel_power_off();	/* Shut down the system. */
505	return 0;
506}
507
508/*
509 * Start up the shutdown task.
510 */
511int torture_shutdown_init(int ssecs, void (*cleanup)(void))
512{
513	int ret = 0;
514
515	torture_shutdown_hook = cleanup;
516	if (ssecs > 0) {
517		shutdown_time = ktime_add(ktime_get(), ktime_set(ssecs, 0));
518		ret = torture_create_kthread(torture_shutdown, NULL,
519					     shutdown_task);
520	}
521	return ret;
522}
523EXPORT_SYMBOL_GPL(torture_shutdown_init);
524
525/*
526 * Detect and respond to a system shutdown.
527 */
528static int torture_shutdown_notify(struct notifier_block *unused1,
529				   unsigned long unused2, void *unused3)
530{
531	mutex_lock(&fullstop_mutex);
532	if (READ_ONCE(fullstop) == FULLSTOP_DONTSTOP) {
533		VERBOSE_TOROUT_STRING("Unscheduled system shutdown detected");
534		WRITE_ONCE(fullstop, FULLSTOP_SHUTDOWN);
535	} else {
536		pr_warn("Concurrent rmmod and shutdown illegal!\n");
537	}
538	mutex_unlock(&fullstop_mutex);
539	return NOTIFY_DONE;
540}
541
542static struct notifier_block torture_shutdown_nb = {
543	.notifier_call = torture_shutdown_notify,
544};
545
546/*
547 * Shut down the shutdown task.  Say what???  Heh!  This can happen if
548 * the torture module gets an rmmod before the shutdown time arrives.  ;-)
549 */
550static void torture_shutdown_cleanup(void)
551{
552	unregister_reboot_notifier(&torture_shutdown_nb);
553	if (shutdown_task != NULL) {
554		VERBOSE_TOROUT_STRING("Stopping torture_shutdown task");
555		kthread_stop(shutdown_task);
556	}
557	shutdown_task = NULL;
558}
559
560/*
561 * Variables for stuttering, which means to periodically pause and
562 * restart testing in order to catch bugs that appear when load is
563 * suddenly applied to or removed from the system.
564 */
565static struct task_struct *stutter_task;
566static int stutter_pause_test;
567static int stutter;
 
568
569/*
570 * Block until the stutter interval ends.  This must be called periodically
571 * by all running kthreads that need to be subject to stuttering.
572 */
573void stutter_wait(const char *title)
574{
575	int spt;
 
576
577	cond_resched_rcu_qs();
578	spt = READ_ONCE(stutter_pause_test);
579	for (; spt; spt = READ_ONCE(stutter_pause_test)) {
580		if (spt == 1) {
581			schedule_timeout_interruptible(1);
582		} else if (spt == 2) {
583			while (READ_ONCE(stutter_pause_test))
584				cond_resched();
585		} else {
586			schedule_timeout_interruptible(round_jiffies_relative(HZ));
587		}
588		torture_shutdown_absorb(title);
589	}
 
 
590}
591EXPORT_SYMBOL_GPL(stutter_wait);
592
593/*
594 * Cause the torture test to "stutter", starting and stopping all
595 * threads periodically.
596 */
597static int torture_stutter(void *arg)
598{
 
 
599	VERBOSE_TOROUT_STRING("torture_stutter task started");
600	do {
601		if (!torture_must_stop() && stutter > 1) {
602			WRITE_ONCE(stutter_pause_test, 1);
603			schedule_timeout_interruptible(stutter - 1);
604			WRITE_ONCE(stutter_pause_test, 2);
605			schedule_timeout_interruptible(1);
606		}
607		WRITE_ONCE(stutter_pause_test, 0);
608		if (!torture_must_stop())
609			schedule_timeout_interruptible(stutter);
610		torture_shutdown_absorb("torture_stutter");
611	} while (!torture_must_stop());
612	torture_kthread_stopping("torture_stutter");
613	return 0;
614}
615
616/*
617 * Initialize and kick off the torture_stutter kthread.
618 */
619int torture_stutter_init(int s)
620{
621	int ret;
622
623	stutter = s;
624	ret = torture_create_kthread(torture_stutter, NULL, stutter_task);
625	return ret;
626}
627EXPORT_SYMBOL_GPL(torture_stutter_init);
628
629/*
630 * Cleanup after the torture_stutter kthread.
631 */
632static void torture_stutter_cleanup(void)
633{
634	if (!stutter_task)
635		return;
636	VERBOSE_TOROUT_STRING("Stopping torture_stutter task");
637	kthread_stop(stutter_task);
638	stutter_task = NULL;
639}
640
 
 
 
 
 
 
 
641/*
642 * Initialize torture module.  Please note that this is -not- invoked via
643 * the usual module_init() mechanism, but rather by an explicit call from
644 * the client torture module.  This call must be paired with a later
645 * torture_init_end().
646 *
647 * The runnable parameter points to a flag that controls whether or not
648 * the test is currently runnable.  If there is no such flag, pass in NULL.
649 */
650bool torture_init_begin(char *ttype, bool v)
651{
652	mutex_lock(&fullstop_mutex);
653	if (torture_type != NULL) {
654		pr_alert("torture_init_begin: Refusing %s init: %s running.\n",
655			 ttype, torture_type);
656		pr_alert("torture_init_begin: One torture test at a time!\n");
657		mutex_unlock(&fullstop_mutex);
658		return false;
659	}
660	torture_type = ttype;
661	verbose = v;
662	fullstop = FULLSTOP_DONTSTOP;
 
663	return true;
664}
665EXPORT_SYMBOL_GPL(torture_init_begin);
666
667/*
668 * Tell the torture module that initialization is complete.
669 */
670void torture_init_end(void)
671{
672	mutex_unlock(&fullstop_mutex);
673	register_reboot_notifier(&torture_shutdown_nb);
674}
675EXPORT_SYMBOL_GPL(torture_init_end);
676
677/*
678 * Clean up torture module.  Please note that this is -not- invoked via
679 * the usual module_exit() mechanism, but rather by an explicit call from
680 * the client torture module.  Returns true if a race with system shutdown
681 * is detected, otherwise, all kthreads started by functions in this file
682 * will be shut down.
683 *
684 * This must be called before the caller starts shutting down its own
685 * kthreads.
686 *
687 * Both torture_cleanup_begin() and torture_cleanup_end() must be paired,
688 * in order to correctly perform the cleanup. They are separated because
689 * threads can still need to reference the torture_type type, thus nullify
690 * only after completing all other relevant calls.
691 */
692bool torture_cleanup_begin(void)
693{
694	mutex_lock(&fullstop_mutex);
695	if (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
696		pr_warn("Concurrent rmmod and shutdown illegal!\n");
697		mutex_unlock(&fullstop_mutex);
698		schedule_timeout_uninterruptible(10);
699		return true;
700	}
701	WRITE_ONCE(fullstop, FULLSTOP_RMMOD);
702	mutex_unlock(&fullstop_mutex);
703	torture_shutdown_cleanup();
704	torture_shuffle_cleanup();
705	torture_stutter_cleanup();
706	torture_onoff_cleanup();
707	return false;
708}
709EXPORT_SYMBOL_GPL(torture_cleanup_begin);
710
711void torture_cleanup_end(void)
712{
713	mutex_lock(&fullstop_mutex);
714	torture_type = NULL;
715	mutex_unlock(&fullstop_mutex);
716}
717EXPORT_SYMBOL_GPL(torture_cleanup_end);
718
719/*
720 * Is it time for the current torture test to stop?
721 */
722bool torture_must_stop(void)
723{
724	return torture_must_stop_irq() || kthread_should_stop();
725}
726EXPORT_SYMBOL_GPL(torture_must_stop);
727
728/*
729 * Is it time for the current torture test to stop?  This is the irq-safe
730 * version, hence no check for kthread_should_stop().
731 */
732bool torture_must_stop_irq(void)
733{
734	return READ_ONCE(fullstop) != FULLSTOP_DONTSTOP;
735}
736EXPORT_SYMBOL_GPL(torture_must_stop_irq);
737
738/*
739 * Each kthread must wait for kthread_should_stop() before returning from
740 * its top-level function, otherwise segfaults ensue.  This function
741 * prints a "stopping" message and waits for kthread_should_stop(), and
742 * should be called from all torture kthreads immediately prior to
743 * returning.
744 */
745void torture_kthread_stopping(char *title)
746{
747	char buf[128];
748
749	snprintf(buf, sizeof(buf), "Stopping %s", title);
750	VERBOSE_TOROUT_STRING(buf);
751	while (!kthread_should_stop()) {
752		torture_shutdown_absorb(title);
753		schedule_timeout_uninterruptible(1);
754	}
755}
756EXPORT_SYMBOL_GPL(torture_kthread_stopping);
757
758/*
759 * Create a generic torture kthread that is immediately runnable.  If you
760 * need the kthread to be stopped so that you can do something to it before
761 * it starts, you will need to open-code your own.
762 */
763int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
764			    char *f, struct task_struct **tp)
765{
766	int ret = 0;
767
768	VERBOSE_TOROUT_STRING(m);
769	*tp = kthread_run(fn, arg, "%s", s);
770	if (IS_ERR(*tp)) {
771		ret = PTR_ERR(*tp);
772		VERBOSE_TOROUT_ERRSTRING(f);
773		*tp = NULL;
 
774	}
 
 
 
 
 
775	torture_shuffle_task_register(*tp);
776	return ret;
777}
778EXPORT_SYMBOL_GPL(_torture_create_kthread);
779
780/*
781 * Stop a generic kthread, emitting a message.
782 */
783void _torture_stop_kthread(char *m, struct task_struct **tp)
784{
785	if (*tp == NULL)
786		return;
787	VERBOSE_TOROUT_STRING(m);
788	kthread_stop(*tp);
789	*tp = NULL;
790}
791EXPORT_SYMBOL_GPL(_torture_stop_kthread);
v6.9.4
  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);