2 * Common functions for in-kernel torture tests.
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.
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.
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.
18 * Copyright (C) IBM Corporation, 2014
20 * Author: Paul E. McKenney <paulmck@us.ibm.com>
21 * Based on kernel/rcu/torture.c.
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>
49 MODULE_LICENSE("GPL");
50 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
52 static char *torture_type;
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. */
59 static int fullstop = FULLSTOP_RMMOD;
60 static DEFINE_MUTEX(fullstop_mutex);
61 static int *torture_runnable;
63 #ifdef CONFIG_HOTPLUG_CPU
66 * Variables for online-offline handling. Only present if CPU hotplug
67 * is enabled, otherwise does nothing.
70 static struct task_struct *onoff_task;
71 static long onoff_holdoff;
72 static long onoff_interval;
73 static long n_offline_attempts;
74 static long n_offline_successes;
75 static unsigned long sum_offline;
76 static int min_offline = -1;
77 static int max_offline;
78 static long n_online_attempts;
79 static long n_online_successes;
80 static unsigned long sum_online;
81 static int min_online = -1;
82 static int max_online;
85 * Execute random CPU-hotplug operations at the interval specified
86 * by the onoff_interval.
89 torture_onoff(void *arg)
94 DEFINE_TORTURE_RANDOM(rand);
96 unsigned long starttime;
98 VERBOSE_TOROUT_STRING("torture_onoff task started");
99 for_each_online_cpu(cpu)
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");
107 while (!torture_must_stop()) {
108 cpu = (torture_random(&rand) >> 4) % (maxcpu + 1);
109 if (cpu_online(cpu) && cpu_is_hotpluggable(cpu)) {
111 pr_alert("%s" TORTURE_FLAG
112 "torture_onoff task: offlining %d\n",
115 n_offline_attempts++;
119 pr_alert("%s" TORTURE_FLAG
120 "torture_onoff task: offline %d failed: errno %d\n",
121 torture_type, cpu, ret);
124 pr_alert("%s" TORTURE_FLAG
125 "torture_onoff task: offlined %d\n",
127 n_offline_successes++;
128 delta = jiffies - starttime;
129 sum_offline += delta;
130 if (min_offline < 0) {
134 if (min_offline > delta)
136 if (max_offline < delta)
139 } else if (cpu_is_hotpluggable(cpu)) {
141 pr_alert("%s" TORTURE_FLAG
142 "torture_onoff task: onlining %d\n",
149 pr_alert("%s" TORTURE_FLAG
150 "torture_onoff task: online %d failed: errno %d\n",
151 torture_type, cpu, ret);
154 pr_alert("%s" TORTURE_FLAG
155 "torture_onoff task: onlined %d\n",
157 n_online_successes++;
158 delta = jiffies - starttime;
160 if (min_online < 0) {
164 if (min_online > delta)
166 if (max_online < delta)
170 schedule_timeout_interruptible(onoff_interval);
172 torture_kthread_stopping("torture_onoff");
176 #endif /* #ifdef CONFIG_HOTPLUG_CPU */
179 * Initiate online-offline handling.
181 int torture_onoff_init(long ooholdoff, long oointerval)
185 #ifdef CONFIG_HOTPLUG_CPU
186 onoff_holdoff = ooholdoff;
187 onoff_interval = oointerval;
188 if (onoff_interval <= 0)
190 ret = torture_create_kthread(torture_onoff, NULL, onoff_task);
191 #endif /* #ifdef CONFIG_HOTPLUG_CPU */
194 EXPORT_SYMBOL_GPL(torture_onoff_init);
197 * Clean up after online/offline testing.
199 static void torture_onoff_cleanup(void)
201 #ifdef CONFIG_HOTPLUG_CPU
202 if (onoff_task == NULL)
204 VERBOSE_TOROUT_STRING("Stopping torture_onoff task");
205 kthread_stop(onoff_task);
207 #endif /* #ifdef CONFIG_HOTPLUG_CPU */
209 EXPORT_SYMBOL_GPL(torture_onoff_cleanup);
212 * Print online/offline testing statistics.
214 void torture_onoff_stats(void)
216 #ifdef CONFIG_HOTPLUG_CPU
217 pr_cont("onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ",
218 n_online_successes, n_online_attempts,
219 n_offline_successes, n_offline_attempts,
220 min_online, max_online,
221 min_offline, max_offline,
222 sum_online, sum_offline, HZ);
223 #endif /* #ifdef CONFIG_HOTPLUG_CPU */
225 EXPORT_SYMBOL_GPL(torture_onoff_stats);
228 * Were all the online/offline operations successful?
230 bool torture_onoff_failures(void)
232 #ifdef CONFIG_HOTPLUG_CPU
233 return n_online_successes != n_online_attempts ||
234 n_offline_successes != n_offline_attempts;
235 #else /* #ifdef CONFIG_HOTPLUG_CPU */
237 #endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
239 EXPORT_SYMBOL_GPL(torture_onoff_failures);
241 #define TORTURE_RANDOM_MULT 39916801 /* prime */
242 #define TORTURE_RANDOM_ADD 479001701 /* prime */
243 #define TORTURE_RANDOM_REFRESH 10000
246 * Crude but fast random-number generator. Uses a linear congruential
247 * generator, with occasional help from cpu_clock().
250 torture_random(struct torture_random_state *trsp)
252 if (--trsp->trs_count < 0) {
253 trsp->trs_state += (unsigned long)local_clock();
254 trsp->trs_count = TORTURE_RANDOM_REFRESH;
256 trsp->trs_state = trsp->trs_state * TORTURE_RANDOM_MULT +
258 return swahw32(trsp->trs_state);
260 EXPORT_SYMBOL_GPL(torture_random);
263 * Variables for shuffling. The idea is to ensure that each CPU stays
264 * idle for an extended period to test interactions with dyntick idle,
265 * as well as interactions with any per-CPU varibles.
267 struct shuffle_task {
268 struct list_head st_l;
269 struct task_struct *st_t;
272 static long shuffle_interval; /* In jiffies. */
273 static struct task_struct *shuffler_task;
274 static cpumask_var_t shuffle_tmp_mask;
275 static int shuffle_idle_cpu; /* Force all torture tasks off this CPU */
276 static struct list_head shuffle_task_list = LIST_HEAD_INIT(shuffle_task_list);
277 static DEFINE_MUTEX(shuffle_task_mutex);
280 * Register a task to be shuffled. If there is no memory, just splat
281 * and don't bother registering.
283 void torture_shuffle_task_register(struct task_struct *tp)
285 struct shuffle_task *stp;
287 if (WARN_ON_ONCE(tp == NULL))
289 stp = kmalloc(sizeof(*stp), GFP_KERNEL);
290 if (WARN_ON_ONCE(stp == NULL))
293 mutex_lock(&shuffle_task_mutex);
294 list_add(&stp->st_l, &shuffle_task_list);
295 mutex_unlock(&shuffle_task_mutex);
297 EXPORT_SYMBOL_GPL(torture_shuffle_task_register);
300 * Unregister all tasks, for example, at the end of the torture run.
302 static void torture_shuffle_task_unregister_all(void)
304 struct shuffle_task *stp;
305 struct shuffle_task *p;
307 mutex_lock(&shuffle_task_mutex);
308 list_for_each_entry_safe(stp, p, &shuffle_task_list, st_l) {
309 list_del(&stp->st_l);
312 mutex_unlock(&shuffle_task_mutex);
315 /* Shuffle tasks such that we allow shuffle_idle_cpu to become idle.
316 * A special case is when shuffle_idle_cpu = -1, in which case we allow
317 * the tasks to run on all CPUs.
319 static void torture_shuffle_tasks(void)
321 struct shuffle_task *stp;
323 cpumask_setall(shuffle_tmp_mask);
326 /* No point in shuffling if there is only one online CPU (ex: UP) */
327 if (num_online_cpus() == 1) {
332 /* Advance to the next CPU. Upon overflow, don't idle any CPUs. */
333 shuffle_idle_cpu = cpumask_next(shuffle_idle_cpu, shuffle_tmp_mask);
334 if (shuffle_idle_cpu >= nr_cpu_ids)
335 shuffle_idle_cpu = -1;
337 cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask);
339 mutex_lock(&shuffle_task_mutex);
340 list_for_each_entry(stp, &shuffle_task_list, st_l)
341 set_cpus_allowed_ptr(stp->st_t, shuffle_tmp_mask);
342 mutex_unlock(&shuffle_task_mutex);
347 /* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
348 * system to become idle at a time and cut off its timer ticks. This is meant
349 * to test the support for such tickless idle CPU in RCU.
351 static int torture_shuffle(void *arg)
353 VERBOSE_TOROUT_STRING("torture_shuffle task started");
355 schedule_timeout_interruptible(shuffle_interval);
356 torture_shuffle_tasks();
357 torture_shutdown_absorb("torture_shuffle");
358 } while (!torture_must_stop());
359 torture_kthread_stopping("torture_shuffle");
364 * Start the shuffler, with shuffint in jiffies.
366 int torture_shuffle_init(long shuffint)
368 shuffle_interval = shuffint;
370 shuffle_idle_cpu = -1;
372 if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
373 VERBOSE_TOROUT_ERRSTRING("Failed to alloc mask");
377 /* Create the shuffler thread */
378 return torture_create_kthread(torture_shuffle, NULL, shuffler_task);
380 EXPORT_SYMBOL_GPL(torture_shuffle_init);
383 * Stop the shuffling.
385 static void torture_shuffle_cleanup(void)
387 torture_shuffle_task_unregister_all();
389 VERBOSE_TOROUT_STRING("Stopping torture_shuffle task");
390 kthread_stop(shuffler_task);
391 free_cpumask_var(shuffle_tmp_mask);
393 shuffler_task = NULL;
395 EXPORT_SYMBOL_GPL(torture_shuffle_cleanup);
398 * Variables for auto-shutdown. This allows "lights out" torture runs
399 * to be fully scripted.
401 static int shutdown_secs; /* desired test duration in seconds. */
402 static struct task_struct *shutdown_task;
403 static unsigned long shutdown_time; /* jiffies to system shutdown. */
404 static void (*torture_shutdown_hook)(void);
407 * Absorb kthreads into a kernel function that won't return, so that
408 * they won't ever access module text or data again.
410 void torture_shutdown_absorb(const char *title)
412 while (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
413 pr_notice("torture thread %s parking due to system shutdown\n",
415 schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
418 EXPORT_SYMBOL_GPL(torture_shutdown_absorb);
421 * Cause the torture test to shutdown the system after the test has
422 * run for the time specified by the shutdown_secs parameter.
424 static int torture_shutdown(void *arg)
427 unsigned long jiffies_snap;
429 VERBOSE_TOROUT_STRING("torture_shutdown task started");
430 jiffies_snap = jiffies;
431 while (ULONG_CMP_LT(jiffies_snap, shutdown_time) &&
432 !torture_must_stop()) {
433 delta = shutdown_time - jiffies_snap;
435 pr_alert("%s" TORTURE_FLAG
436 "torture_shutdown task: %lu jiffies remaining\n",
437 torture_type, delta);
438 schedule_timeout_interruptible(delta);
439 jiffies_snap = jiffies;
441 if (torture_must_stop()) {
442 torture_kthread_stopping("torture_shutdown");
446 /* OK, shut down the system. */
448 VERBOSE_TOROUT_STRING("torture_shutdown task shutting down system");
449 shutdown_task = NULL; /* Avoid self-kill deadlock. */
450 if (torture_shutdown_hook)
451 torture_shutdown_hook();
453 VERBOSE_TOROUT_STRING("No torture_shutdown_hook(), skipping.");
454 kernel_power_off(); /* Shut down the system. */
459 * Start up the shutdown task.
461 int torture_shutdown_init(int ssecs, void (*cleanup)(void))
465 shutdown_secs = ssecs;
466 torture_shutdown_hook = cleanup;
467 if (shutdown_secs > 0) {
468 shutdown_time = jiffies + shutdown_secs * HZ;
469 ret = torture_create_kthread(torture_shutdown, NULL,
474 EXPORT_SYMBOL_GPL(torture_shutdown_init);
477 * Detect and respond to a system shutdown.
479 static int torture_shutdown_notify(struct notifier_block *unused1,
480 unsigned long unused2, void *unused3)
482 mutex_lock(&fullstop_mutex);
483 if (ACCESS_ONCE(fullstop) == FULLSTOP_DONTSTOP) {
484 VERBOSE_TOROUT_STRING("Unscheduled system shutdown detected");
485 ACCESS_ONCE(fullstop) = FULLSTOP_SHUTDOWN;
487 pr_warn("Concurrent rmmod and shutdown illegal!\n");
489 mutex_unlock(&fullstop_mutex);
493 static struct notifier_block torture_shutdown_nb = {
494 .notifier_call = torture_shutdown_notify,
498 * Shut down the shutdown task. Say what??? Heh! This can happen if
499 * the torture module gets an rmmod before the shutdown time arrives. ;-)
501 static void torture_shutdown_cleanup(void)
503 unregister_reboot_notifier(&torture_shutdown_nb);
504 if (shutdown_task != NULL) {
505 VERBOSE_TOROUT_STRING("Stopping torture_shutdown task");
506 kthread_stop(shutdown_task);
508 shutdown_task = NULL;
512 * Variables for stuttering, which means to periodically pause and
513 * restart testing in order to catch bugs that appear when load is
514 * suddenly applied to or removed from the system.
516 static struct task_struct *stutter_task;
517 static int stutter_pause_test;
521 * Block until the stutter interval ends. This must be called periodically
522 * by all running kthreads that need to be subject to stuttering.
524 void stutter_wait(const char *title)
526 while (ACCESS_ONCE(stutter_pause_test) ||
527 (torture_runnable && !ACCESS_ONCE(*torture_runnable))) {
528 if (stutter_pause_test)
529 if (ACCESS_ONCE(stutter_pause_test) == 1)
530 schedule_timeout_interruptible(1);
532 while (ACCESS_ONCE(stutter_pause_test))
535 schedule_timeout_interruptible(round_jiffies_relative(HZ));
536 torture_shutdown_absorb(title);
539 EXPORT_SYMBOL_GPL(stutter_wait);
542 * Cause the torture test to "stutter", starting and stopping all
543 * threads periodically.
545 static int torture_stutter(void *arg)
547 VERBOSE_TOROUT_STRING("torture_stutter task started");
549 if (!torture_must_stop()) {
551 schedule_timeout_interruptible(stutter - 1);
552 ACCESS_ONCE(stutter_pause_test) = 2;
554 schedule_timeout_interruptible(1);
555 ACCESS_ONCE(stutter_pause_test) = 1;
557 if (!torture_must_stop())
558 schedule_timeout_interruptible(stutter);
559 ACCESS_ONCE(stutter_pause_test) = 0;
560 torture_shutdown_absorb("torture_stutter");
561 } while (!torture_must_stop());
562 torture_kthread_stopping("torture_stutter");
567 * Initialize and kick off the torture_stutter kthread.
569 int torture_stutter_init(int s)
574 ret = torture_create_kthread(torture_stutter, NULL, stutter_task);
577 EXPORT_SYMBOL_GPL(torture_stutter_init);
580 * Cleanup after the torture_stutter kthread.
582 static void torture_stutter_cleanup(void)
586 VERBOSE_TOROUT_STRING("Stopping torture_stutter task");
587 kthread_stop(stutter_task);
592 * Initialize torture module. Please note that this is -not- invoked via
593 * the usual module_init() mechanism, but rather by an explicit call from
594 * the client torture module. This call must be paired with a later
595 * torture_init_end().
597 * The runnable parameter points to a flag that controls whether or not
598 * the test is currently runnable. If there is no such flag, pass in NULL.
600 bool torture_init_begin(char *ttype, bool v, int *runnable)
602 mutex_lock(&fullstop_mutex);
603 if (torture_type != NULL) {
604 pr_alert("torture_init_begin: refusing %s init: %s running",
605 ttype, torture_type);
606 mutex_unlock(&fullstop_mutex);
609 torture_type = ttype;
611 torture_runnable = runnable;
612 fullstop = FULLSTOP_DONTSTOP;
615 EXPORT_SYMBOL_GPL(torture_init_begin);
618 * Tell the torture module that initialization is complete.
620 void torture_init_end(void)
622 mutex_unlock(&fullstop_mutex);
623 register_reboot_notifier(&torture_shutdown_nb);
625 EXPORT_SYMBOL_GPL(torture_init_end);
628 * Clean up torture module. Please note that this is -not- invoked via
629 * the usual module_exit() mechanism, but rather by an explicit call from
630 * the client torture module. Returns true if a race with system shutdown
631 * is detected, otherwise, all kthreads started by functions in this file
634 * This must be called before the caller starts shutting down its own
637 * Both torture_cleanup_begin() and torture_cleanup_end() must be paired,
638 * in order to correctly perform the cleanup. They are separated because
639 * threads can still need to reference the torture_type type, thus nullify
640 * only after completing all other relevant calls.
642 bool torture_cleanup_begin(void)
644 mutex_lock(&fullstop_mutex);
645 if (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
646 pr_warn("Concurrent rmmod and shutdown illegal!\n");
647 mutex_unlock(&fullstop_mutex);
648 schedule_timeout_uninterruptible(10);
651 ACCESS_ONCE(fullstop) = FULLSTOP_RMMOD;
652 mutex_unlock(&fullstop_mutex);
653 torture_shutdown_cleanup();
654 torture_shuffle_cleanup();
655 torture_stutter_cleanup();
656 torture_onoff_cleanup();
659 EXPORT_SYMBOL_GPL(torture_cleanup_begin);
661 void torture_cleanup_end(void)
663 mutex_lock(&fullstop_mutex);
665 mutex_unlock(&fullstop_mutex);
667 EXPORT_SYMBOL_GPL(torture_cleanup_end);
670 * Is it time for the current torture test to stop?
672 bool torture_must_stop(void)
674 return torture_must_stop_irq() || kthread_should_stop();
676 EXPORT_SYMBOL_GPL(torture_must_stop);
679 * Is it time for the current torture test to stop? This is the irq-safe
680 * version, hence no check for kthread_should_stop().
682 bool torture_must_stop_irq(void)
684 return ACCESS_ONCE(fullstop) != FULLSTOP_DONTSTOP;
686 EXPORT_SYMBOL_GPL(torture_must_stop_irq);
689 * Each kthread must wait for kthread_should_stop() before returning from
690 * its top-level function, otherwise segfaults ensue. This function
691 * prints a "stopping" message and waits for kthread_should_stop(), and
692 * should be called from all torture kthreads immediately prior to
695 void torture_kthread_stopping(char *title)
699 snprintf(buf, sizeof(buf), "Stopping %s", title);
700 VERBOSE_TOROUT_STRING(buf);
701 while (!kthread_should_stop()) {
702 torture_shutdown_absorb(title);
703 schedule_timeout_uninterruptible(1);
706 EXPORT_SYMBOL_GPL(torture_kthread_stopping);
709 * Create a generic torture kthread that is immediately runnable. If you
710 * need the kthread to be stopped so that you can do something to it before
711 * it starts, you will need to open-code your own.
713 int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
714 char *f, struct task_struct **tp)
718 VERBOSE_TOROUT_STRING(m);
719 *tp = kthread_run(fn, arg, "%s", s);
722 VERBOSE_TOROUT_ERRSTRING(f);
725 torture_shuffle_task_register(*tp);
728 EXPORT_SYMBOL_GPL(_torture_create_kthread);
731 * Stop a generic kthread, emitting a message.
733 void _torture_stop_kthread(char *m, struct task_struct **tp)
737 VERBOSE_TOROUT_STRING(m);
741 EXPORT_SYMBOL_GPL(_torture_stop_kthread);