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
24 #define pr_fmt(fmt) fmt
25
26 #include <linux/types.h>
27 #include <linux/kernel.h>
28 #include <linux/init.h>
29 #include <linux/module.h>
30 #include <linux/kthread.h>
31 #include <linux/err.h>
32 #include <linux/spinlock.h>
33 #include <linux/smp.h>
34 #include <linux/interrupt.h>
35 #include <linux/sched.h>
36 #include <linux/sched/clock.h>
37 #include <linux/atomic.h>
38 #include <linux/bitops.h>
39 #include <linux/completion.h>
40 #include <linux/moduleparam.h>
41 #include <linux/percpu.h>
42 #include <linux/notifier.h>
43 #include <linux/reboot.h>
44 #include <linux/freezer.h>
45 #include <linux/cpu.h>
46 #include <linux/delay.h>
47 #include <linux/stat.h>
48 #include <linux/slab.h>
49 #include <linux/trace_clock.h>
50 #include <linux/ktime.h>
51 #include <asm/byteorder.h>
52 #include <linux/torture.h>
53 #include "rcu/rcu.h"
54
55 MODULE_LICENSE("GPL");
56 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
57
58 static char *torture_type;
59 static int verbose;
60
61 /* Mediate rmmod and system shutdown. Concurrent rmmod & shutdown illegal! */
62 #define FULLSTOP_DONTSTOP 0 /* Normal operation. */
63 #define FULLSTOP_SHUTDOWN 1 /* System shutdown with torture running. */
64 #define FULLSTOP_RMMOD 2 /* Normal rmmod of torture. */
65 static int fullstop = FULLSTOP_RMMOD;
66 static DEFINE_MUTEX(fullstop_mutex);
67
68 #ifdef CONFIG_HOTPLUG_CPU
69
70 /*
71 * Variables for online-offline handling. Only present if CPU hotplug
72 * is enabled, otherwise does nothing.
73 */
74
75 static struct task_struct *onoff_task;
76 static long onoff_holdoff;
77 static long onoff_interval;
78 static long n_offline_attempts;
79 static long n_offline_successes;
80 static unsigned long sum_offline;
81 static int min_offline = -1;
82 static int max_offline;
83 static long n_online_attempts;
84 static long n_online_successes;
85 static unsigned long sum_online;
86 static int min_online = -1;
87 static int max_online;
88
89 /*
90 * Attempt to take a CPU offline. Return false if the CPU is already
91 * offline or if it is not subject to CPU-hotplug operations. The
92 * caller can detect other failures by looking at the statistics.
93 */
torture_offline(int cpu,long * n_offl_attempts,long * n_offl_successes,unsigned long * sum_offl,int * min_offl,int * max_offl)94 bool torture_offline(int cpu, long *n_offl_attempts, long *n_offl_successes,
95 unsigned long *sum_offl, int *min_offl, int *max_offl)
96 {
97 unsigned long delta;
98 int ret;
99 unsigned long starttime;
100
101 if (!cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
102 return false;
103
104 if (verbose > 1)
105 pr_alert("%s" TORTURE_FLAG
106 "torture_onoff task: offlining %d\n",
107 torture_type, cpu);
108 starttime = jiffies;
109 (*n_offl_attempts)++;
110 ret = cpu_down(cpu);
111 if (ret) {
112 if (verbose)
113 pr_alert("%s" TORTURE_FLAG
114 "torture_onoff task: offline %d failed: errno %d\n",
115 torture_type, cpu, ret);
116 } else {
117 if (verbose > 1)
118 pr_alert("%s" TORTURE_FLAG
119 "torture_onoff task: offlined %d\n",
120 torture_type, cpu);
121 (*n_offl_successes)++;
122 delta = jiffies - starttime;
123 *sum_offl += delta;
124 if (*min_offl < 0) {
125 *min_offl = delta;
126 *max_offl = delta;
127 }
128 if (*min_offl > delta)
129 *min_offl = delta;
130 if (*max_offl < delta)
131 *max_offl = delta;
132 }
133
134 return true;
135 }
136 EXPORT_SYMBOL_GPL(torture_offline);
137
138 /*
139 * Attempt to bring a CPU online. Return false if the CPU is already
140 * online or if it is not subject to CPU-hotplug operations. The
141 * caller can detect other failures by looking at the statistics.
142 */
torture_online(int cpu,long * n_onl_attempts,long * n_onl_successes,unsigned long * sum_onl,int * min_onl,int * max_onl)143 bool torture_online(int cpu, long *n_onl_attempts, long *n_onl_successes,
144 unsigned long *sum_onl, int *min_onl, int *max_onl)
145 {
146 unsigned long delta;
147 int ret;
148 unsigned long starttime;
149
150 if (cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
151 return false;
152
153 if (verbose > 1)
154 pr_alert("%s" TORTURE_FLAG
155 "torture_onoff task: onlining %d\n",
156 torture_type, cpu);
157 starttime = jiffies;
158 (*n_onl_attempts)++;
159 ret = cpu_up(cpu);
160 if (ret) {
161 if (verbose)
162 pr_alert("%s" TORTURE_FLAG
163 "torture_onoff task: online %d failed: errno %d\n",
164 torture_type, cpu, ret);
165 } else {
166 if (verbose > 1)
167 pr_alert("%s" TORTURE_FLAG
168 "torture_onoff task: onlined %d\n",
169 torture_type, cpu);
170 (*n_onl_successes)++;
171 delta = jiffies - starttime;
172 *sum_onl += delta;
173 if (*min_onl < 0) {
174 *min_onl = delta;
175 *max_onl = delta;
176 }
177 if (*min_onl > delta)
178 *min_onl = delta;
179 if (*max_onl < delta)
180 *max_onl = delta;
181 }
182
183 return true;
184 }
185 EXPORT_SYMBOL_GPL(torture_online);
186
187 /*
188 * Execute random CPU-hotplug operations at the interval specified
189 * by the onoff_interval.
190 */
191 static int
torture_onoff(void * arg)192 torture_onoff(void *arg)
193 {
194 int cpu;
195 int maxcpu = -1;
196 DEFINE_TORTURE_RANDOM(rand);
197
198 VERBOSE_TOROUT_STRING("torture_onoff task started");
199 for_each_online_cpu(cpu)
200 maxcpu = cpu;
201 WARN_ON(maxcpu < 0);
202
203 if (maxcpu == 0) {
204 VERBOSE_TOROUT_STRING("Only one CPU, so CPU-hotplug testing is disabled");
205 goto stop;
206 }
207
208 if (onoff_holdoff > 0) {
209 VERBOSE_TOROUT_STRING("torture_onoff begin holdoff");
210 schedule_timeout_interruptible(onoff_holdoff);
211 VERBOSE_TOROUT_STRING("torture_onoff end holdoff");
212 }
213 while (!torture_must_stop()) {
214 cpu = (torture_random(&rand) >> 4) % (maxcpu + 1);
215 if (!torture_offline(cpu,
216 &n_offline_attempts, &n_offline_successes,
217 &sum_offline, &min_offline, &max_offline))
218 torture_online(cpu,
219 &n_online_attempts, &n_online_successes,
220 &sum_online, &min_online, &max_online);
221 schedule_timeout_interruptible(onoff_interval);
222 }
223
224 stop:
225 torture_kthread_stopping("torture_onoff");
226 return 0;
227 }
228
229 #endif /* #ifdef CONFIG_HOTPLUG_CPU */
230
231 /*
232 * Initiate online-offline handling.
233 */
torture_onoff_init(long ooholdoff,long oointerval)234 int torture_onoff_init(long ooholdoff, long oointerval)
235 {
236 int ret = 0;
237
238 #ifdef CONFIG_HOTPLUG_CPU
239 onoff_holdoff = ooholdoff;
240 onoff_interval = oointerval;
241 if (onoff_interval <= 0)
242 return 0;
243 ret = torture_create_kthread(torture_onoff, NULL, onoff_task);
244 #endif /* #ifdef CONFIG_HOTPLUG_CPU */
245 return ret;
246 }
247 EXPORT_SYMBOL_GPL(torture_onoff_init);
248
249 /*
250 * Clean up after online/offline testing.
251 */
torture_onoff_cleanup(void)252 static void torture_onoff_cleanup(void)
253 {
254 #ifdef CONFIG_HOTPLUG_CPU
255 if (onoff_task == NULL)
256 return;
257 VERBOSE_TOROUT_STRING("Stopping torture_onoff task");
258 kthread_stop(onoff_task);
259 onoff_task = NULL;
260 #endif /* #ifdef CONFIG_HOTPLUG_CPU */
261 }
262 EXPORT_SYMBOL_GPL(torture_onoff_cleanup);
263
264 /*
265 * Print online/offline testing statistics.
266 */
torture_onoff_stats(void)267 void torture_onoff_stats(void)
268 {
269 #ifdef CONFIG_HOTPLUG_CPU
270 pr_cont("onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ",
271 n_online_successes, n_online_attempts,
272 n_offline_successes, n_offline_attempts,
273 min_online, max_online,
274 min_offline, max_offline,
275 sum_online, sum_offline, HZ);
276 #endif /* #ifdef CONFIG_HOTPLUG_CPU */
277 }
278 EXPORT_SYMBOL_GPL(torture_onoff_stats);
279
280 /*
281 * Were all the online/offline operations successful?
282 */
torture_onoff_failures(void)283 bool torture_onoff_failures(void)
284 {
285 #ifdef CONFIG_HOTPLUG_CPU
286 return n_online_successes != n_online_attempts ||
287 n_offline_successes != n_offline_attempts;
288 #else /* #ifdef CONFIG_HOTPLUG_CPU */
289 return false;
290 #endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
291 }
292 EXPORT_SYMBOL_GPL(torture_onoff_failures);
293
294 #define TORTURE_RANDOM_MULT 39916801 /* prime */
295 #define TORTURE_RANDOM_ADD 479001701 /* prime */
296 #define TORTURE_RANDOM_REFRESH 10000
297
298 /*
299 * Crude but fast random-number generator. Uses a linear congruential
300 * generator, with occasional help from cpu_clock().
301 */
302 unsigned long
torture_random(struct torture_random_state * trsp)303 torture_random(struct torture_random_state *trsp)
304 {
305 if (--trsp->trs_count < 0) {
306 trsp->trs_state += (unsigned long)local_clock();
307 trsp->trs_count = TORTURE_RANDOM_REFRESH;
308 }
309 trsp->trs_state = trsp->trs_state * TORTURE_RANDOM_MULT +
310 TORTURE_RANDOM_ADD;
311 return swahw32(trsp->trs_state);
312 }
313 EXPORT_SYMBOL_GPL(torture_random);
314
315 /*
316 * Variables for shuffling. The idea is to ensure that each CPU stays
317 * idle for an extended period to test interactions with dyntick idle,
318 * as well as interactions with any per-CPU variables.
319 */
320 struct shuffle_task {
321 struct list_head st_l;
322 struct task_struct *st_t;
323 };
324
325 static long shuffle_interval; /* In jiffies. */
326 static struct task_struct *shuffler_task;
327 static cpumask_var_t shuffle_tmp_mask;
328 static int shuffle_idle_cpu; /* Force all torture tasks off this CPU */
329 static struct list_head shuffle_task_list = LIST_HEAD_INIT(shuffle_task_list);
330 static DEFINE_MUTEX(shuffle_task_mutex);
331
332 /*
333 * Register a task to be shuffled. If there is no memory, just splat
334 * and don't bother registering.
335 */
torture_shuffle_task_register(struct task_struct * tp)336 void torture_shuffle_task_register(struct task_struct *tp)
337 {
338 struct shuffle_task *stp;
339
340 if (WARN_ON_ONCE(tp == NULL))
341 return;
342 stp = kmalloc(sizeof(*stp), GFP_KERNEL);
343 if (WARN_ON_ONCE(stp == NULL))
344 return;
345 stp->st_t = tp;
346 mutex_lock(&shuffle_task_mutex);
347 list_add(&stp->st_l, &shuffle_task_list);
348 mutex_unlock(&shuffle_task_mutex);
349 }
350 EXPORT_SYMBOL_GPL(torture_shuffle_task_register);
351
352 /*
353 * Unregister all tasks, for example, at the end of the torture run.
354 */
torture_shuffle_task_unregister_all(void)355 static void torture_shuffle_task_unregister_all(void)
356 {
357 struct shuffle_task *stp;
358 struct shuffle_task *p;
359
360 mutex_lock(&shuffle_task_mutex);
361 list_for_each_entry_safe(stp, p, &shuffle_task_list, st_l) {
362 list_del(&stp->st_l);
363 kfree(stp);
364 }
365 mutex_unlock(&shuffle_task_mutex);
366 }
367
368 /* Shuffle tasks such that we allow shuffle_idle_cpu to become idle.
369 * A special case is when shuffle_idle_cpu = -1, in which case we allow
370 * the tasks to run on all CPUs.
371 */
torture_shuffle_tasks(void)372 static void torture_shuffle_tasks(void)
373 {
374 struct shuffle_task *stp;
375
376 cpumask_setall(shuffle_tmp_mask);
377 get_online_cpus();
378
379 /* No point in shuffling if there is only one online CPU (ex: UP) */
380 if (num_online_cpus() == 1) {
381 put_online_cpus();
382 return;
383 }
384
385 /* Advance to the next CPU. Upon overflow, don't idle any CPUs. */
386 shuffle_idle_cpu = cpumask_next(shuffle_idle_cpu, shuffle_tmp_mask);
387 if (shuffle_idle_cpu >= nr_cpu_ids)
388 shuffle_idle_cpu = -1;
389 else
390 cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask);
391
392 mutex_lock(&shuffle_task_mutex);
393 list_for_each_entry(stp, &shuffle_task_list, st_l)
394 set_cpus_allowed_ptr(stp->st_t, shuffle_tmp_mask);
395 mutex_unlock(&shuffle_task_mutex);
396
397 put_online_cpus();
398 }
399
400 /* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
401 * system to become idle at a time and cut off its timer ticks. This is meant
402 * to test the support for such tickless idle CPU in RCU.
403 */
torture_shuffle(void * arg)404 static int torture_shuffle(void *arg)
405 {
406 VERBOSE_TOROUT_STRING("torture_shuffle task started");
407 do {
408 schedule_timeout_interruptible(shuffle_interval);
409 torture_shuffle_tasks();
410 torture_shutdown_absorb("torture_shuffle");
411 } while (!torture_must_stop());
412 torture_kthread_stopping("torture_shuffle");
413 return 0;
414 }
415
416 /*
417 * Start the shuffler, with shuffint in jiffies.
418 */
torture_shuffle_init(long shuffint)419 int torture_shuffle_init(long shuffint)
420 {
421 shuffle_interval = shuffint;
422
423 shuffle_idle_cpu = -1;
424
425 if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
426 VERBOSE_TOROUT_ERRSTRING("Failed to alloc mask");
427 return -ENOMEM;
428 }
429
430 /* Create the shuffler thread */
431 return torture_create_kthread(torture_shuffle, NULL, shuffler_task);
432 }
433 EXPORT_SYMBOL_GPL(torture_shuffle_init);
434
435 /*
436 * Stop the shuffling.
437 */
torture_shuffle_cleanup(void)438 static void torture_shuffle_cleanup(void)
439 {
440 torture_shuffle_task_unregister_all();
441 if (shuffler_task) {
442 VERBOSE_TOROUT_STRING("Stopping torture_shuffle task");
443 kthread_stop(shuffler_task);
444 free_cpumask_var(shuffle_tmp_mask);
445 }
446 shuffler_task = NULL;
447 }
448 EXPORT_SYMBOL_GPL(torture_shuffle_cleanup);
449
450 /*
451 * Variables for auto-shutdown. This allows "lights out" torture runs
452 * to be fully scripted.
453 */
454 static struct task_struct *shutdown_task;
455 static ktime_t shutdown_time; /* time to system shutdown. */
456 static void (*torture_shutdown_hook)(void);
457
458 /*
459 * Absorb kthreads into a kernel function that won't return, so that
460 * they won't ever access module text or data again.
461 */
torture_shutdown_absorb(const char * title)462 void torture_shutdown_absorb(const char *title)
463 {
464 while (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
465 pr_notice("torture thread %s parking due to system shutdown\n",
466 title);
467 schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
468 }
469 }
470 EXPORT_SYMBOL_GPL(torture_shutdown_absorb);
471
472 /*
473 * Cause the torture test to shutdown the system after the test has
474 * run for the time specified by the shutdown_secs parameter.
475 */
torture_shutdown(void * arg)476 static int torture_shutdown(void *arg)
477 {
478 ktime_t ktime_snap;
479
480 VERBOSE_TOROUT_STRING("torture_shutdown task started");
481 ktime_snap = ktime_get();
482 while (ktime_before(ktime_snap, shutdown_time) &&
483 !torture_must_stop()) {
484 if (verbose)
485 pr_alert("%s" TORTURE_FLAG
486 "torture_shutdown task: %llu ms remaining\n",
487 torture_type,
488 ktime_ms_delta(shutdown_time, ktime_snap));
489 set_current_state(TASK_INTERRUPTIBLE);
490 schedule_hrtimeout(&shutdown_time, HRTIMER_MODE_ABS);
491 ktime_snap = ktime_get();
492 }
493 if (torture_must_stop()) {
494 torture_kthread_stopping("torture_shutdown");
495 return 0;
496 }
497
498 /* OK, shut down the system. */
499
500 VERBOSE_TOROUT_STRING("torture_shutdown task shutting down system");
501 shutdown_task = NULL; /* Avoid self-kill deadlock. */
502 if (torture_shutdown_hook)
503 torture_shutdown_hook();
504 else
505 VERBOSE_TOROUT_STRING("No torture_shutdown_hook(), skipping.");
506 rcu_ftrace_dump(DUMP_ALL);
507 kernel_power_off(); /* Shut down the system. */
508 return 0;
509 }
510
511 /*
512 * Start up the shutdown task.
513 */
torture_shutdown_init(int ssecs,void (* cleanup)(void))514 int torture_shutdown_init(int ssecs, void (*cleanup)(void))
515 {
516 int ret = 0;
517
518 torture_shutdown_hook = cleanup;
519 if (ssecs > 0) {
520 shutdown_time = ktime_add(ktime_get(), ktime_set(ssecs, 0));
521 ret = torture_create_kthread(torture_shutdown, NULL,
522 shutdown_task);
523 }
524 return ret;
525 }
526 EXPORT_SYMBOL_GPL(torture_shutdown_init);
527
528 /*
529 * Detect and respond to a system shutdown.
530 */
torture_shutdown_notify(struct notifier_block * unused1,unsigned long unused2,void * unused3)531 static int torture_shutdown_notify(struct notifier_block *unused1,
532 unsigned long unused2, void *unused3)
533 {
534 mutex_lock(&fullstop_mutex);
535 if (READ_ONCE(fullstop) == FULLSTOP_DONTSTOP) {
536 VERBOSE_TOROUT_STRING("Unscheduled system shutdown detected");
537 WRITE_ONCE(fullstop, FULLSTOP_SHUTDOWN);
538 } else {
539 pr_warn("Concurrent rmmod and shutdown illegal!\n");
540 }
541 mutex_unlock(&fullstop_mutex);
542 return NOTIFY_DONE;
543 }
544
545 static struct notifier_block torture_shutdown_nb = {
546 .notifier_call = torture_shutdown_notify,
547 };
548
549 /*
550 * Shut down the shutdown task. Say what??? Heh! This can happen if
551 * the torture module gets an rmmod before the shutdown time arrives. ;-)
552 */
torture_shutdown_cleanup(void)553 static void torture_shutdown_cleanup(void)
554 {
555 unregister_reboot_notifier(&torture_shutdown_nb);
556 if (shutdown_task != NULL) {
557 VERBOSE_TOROUT_STRING("Stopping torture_shutdown task");
558 kthread_stop(shutdown_task);
559 }
560 shutdown_task = NULL;
561 }
562
563 /*
564 * Variables for stuttering, which means to periodically pause and
565 * restart testing in order to catch bugs that appear when load is
566 * suddenly applied to or removed from the system.
567 */
568 static struct task_struct *stutter_task;
569 static int stutter_pause_test;
570 static int stutter;
571
572 /*
573 * Block until the stutter interval ends. This must be called periodically
574 * by all running kthreads that need to be subject to stuttering.
575 */
stutter_wait(const char * title)576 void stutter_wait(const char *title)
577 {
578 int spt;
579
580 cond_resched_tasks_rcu_qs();
581 spt = READ_ONCE(stutter_pause_test);
582 for (; spt; spt = READ_ONCE(stutter_pause_test)) {
583 if (spt == 1) {
584 schedule_timeout_interruptible(1);
585 } else if (spt == 2) {
586 while (READ_ONCE(stutter_pause_test))
587 cond_resched();
588 } else {
589 schedule_timeout_interruptible(round_jiffies_relative(HZ));
590 }
591 torture_shutdown_absorb(title);
592 }
593 }
594 EXPORT_SYMBOL_GPL(stutter_wait);
595
596 /*
597 * Cause the torture test to "stutter", starting and stopping all
598 * threads periodically.
599 */
torture_stutter(void * arg)600 static int torture_stutter(void *arg)
601 {
602 VERBOSE_TOROUT_STRING("torture_stutter task started");
603 do {
604 if (!torture_must_stop() && stutter > 1) {
605 WRITE_ONCE(stutter_pause_test, 1);
606 schedule_timeout_interruptible(stutter - 1);
607 WRITE_ONCE(stutter_pause_test, 2);
608 schedule_timeout_interruptible(1);
609 }
610 WRITE_ONCE(stutter_pause_test, 0);
611 if (!torture_must_stop())
612 schedule_timeout_interruptible(stutter);
613 torture_shutdown_absorb("torture_stutter");
614 } while (!torture_must_stop());
615 torture_kthread_stopping("torture_stutter");
616 return 0;
617 }
618
619 /*
620 * Initialize and kick off the torture_stutter kthread.
621 */
torture_stutter_init(int s)622 int torture_stutter_init(int s)
623 {
624 int ret;
625
626 stutter = s;
627 ret = torture_create_kthread(torture_stutter, NULL, stutter_task);
628 return ret;
629 }
630 EXPORT_SYMBOL_GPL(torture_stutter_init);
631
632 /*
633 * Cleanup after the torture_stutter kthread.
634 */
torture_stutter_cleanup(void)635 static void torture_stutter_cleanup(void)
636 {
637 if (!stutter_task)
638 return;
639 VERBOSE_TOROUT_STRING("Stopping torture_stutter task");
640 kthread_stop(stutter_task);
641 stutter_task = NULL;
642 }
643
644 /*
645 * Initialize torture module. Please note that this is -not- invoked via
646 * the usual module_init() mechanism, but rather by an explicit call from
647 * the client torture module. This call must be paired with a later
648 * torture_init_end().
649 *
650 * The runnable parameter points to a flag that controls whether or not
651 * the test is currently runnable. If there is no such flag, pass in NULL.
652 */
torture_init_begin(char * ttype,int v)653 bool torture_init_begin(char *ttype, int v)
654 {
655 mutex_lock(&fullstop_mutex);
656 if (torture_type != NULL) {
657 pr_alert("torture_init_begin: Refusing %s init: %s running.\n",
658 ttype, torture_type);
659 pr_alert("torture_init_begin: One torture test at a time!\n");
660 mutex_unlock(&fullstop_mutex);
661 return false;
662 }
663 torture_type = ttype;
664 verbose = v;
665 fullstop = FULLSTOP_DONTSTOP;
666 return true;
667 }
668 EXPORT_SYMBOL_GPL(torture_init_begin);
669
670 /*
671 * Tell the torture module that initialization is complete.
672 */
torture_init_end(void)673 void torture_init_end(void)
674 {
675 mutex_unlock(&fullstop_mutex);
676 register_reboot_notifier(&torture_shutdown_nb);
677 }
678 EXPORT_SYMBOL_GPL(torture_init_end);
679
680 /*
681 * Clean up torture module. Please note that this is -not- invoked via
682 * the usual module_exit() mechanism, but rather by an explicit call from
683 * the client torture module. Returns true if a race with system shutdown
684 * is detected, otherwise, all kthreads started by functions in this file
685 * will be shut down.
686 *
687 * This must be called before the caller starts shutting down its own
688 * kthreads.
689 *
690 * Both torture_cleanup_begin() and torture_cleanup_end() must be paired,
691 * in order to correctly perform the cleanup. They are separated because
692 * threads can still need to reference the torture_type type, thus nullify
693 * only after completing all other relevant calls.
694 */
torture_cleanup_begin(void)695 bool torture_cleanup_begin(void)
696 {
697 mutex_lock(&fullstop_mutex);
698 if (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
699 pr_warn("Concurrent rmmod and shutdown illegal!\n");
700 mutex_unlock(&fullstop_mutex);
701 schedule_timeout_uninterruptible(10);
702 return true;
703 }
704 WRITE_ONCE(fullstop, FULLSTOP_RMMOD);
705 mutex_unlock(&fullstop_mutex);
706 torture_shutdown_cleanup();
707 torture_shuffle_cleanup();
708 torture_stutter_cleanup();
709 torture_onoff_cleanup();
710 return false;
711 }
712 EXPORT_SYMBOL_GPL(torture_cleanup_begin);
713
torture_cleanup_end(void)714 void torture_cleanup_end(void)
715 {
716 mutex_lock(&fullstop_mutex);
717 torture_type = NULL;
718 mutex_unlock(&fullstop_mutex);
719 }
720 EXPORT_SYMBOL_GPL(torture_cleanup_end);
721
722 /*
723 * Is it time for the current torture test to stop?
724 */
torture_must_stop(void)725 bool torture_must_stop(void)
726 {
727 return torture_must_stop_irq() || kthread_should_stop();
728 }
729 EXPORT_SYMBOL_GPL(torture_must_stop);
730
731 /*
732 * Is it time for the current torture test to stop? This is the irq-safe
733 * version, hence no check for kthread_should_stop().
734 */
torture_must_stop_irq(void)735 bool torture_must_stop_irq(void)
736 {
737 return READ_ONCE(fullstop) != FULLSTOP_DONTSTOP;
738 }
739 EXPORT_SYMBOL_GPL(torture_must_stop_irq);
740
741 /*
742 * Each kthread must wait for kthread_should_stop() before returning from
743 * its top-level function, otherwise segfaults ensue. This function
744 * prints a "stopping" message and waits for kthread_should_stop(), and
745 * should be called from all torture kthreads immediately prior to
746 * returning.
747 */
torture_kthread_stopping(char * title)748 void torture_kthread_stopping(char *title)
749 {
750 char buf[128];
751
752 snprintf(buf, sizeof(buf), "Stopping %s", title);
753 VERBOSE_TOROUT_STRING(buf);
754 while (!kthread_should_stop()) {
755 torture_shutdown_absorb(title);
756 schedule_timeout_uninterruptible(1);
757 }
758 }
759 EXPORT_SYMBOL_GPL(torture_kthread_stopping);
760
761 /*
762 * Create a generic torture kthread that is immediately runnable. If you
763 * need the kthread to be stopped so that you can do something to it before
764 * it starts, you will need to open-code your own.
765 */
_torture_create_kthread(int (* fn)(void * arg),void * arg,char * s,char * m,char * f,struct task_struct ** tp)766 int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
767 char *f, struct task_struct **tp)
768 {
769 int ret = 0;
770
771 VERBOSE_TOROUT_STRING(m);
772 *tp = kthread_run(fn, arg, "%s", s);
773 if (IS_ERR(*tp)) {
774 ret = PTR_ERR(*tp);
775 VERBOSE_TOROUT_ERRSTRING(f);
776 *tp = NULL;
777 }
778 torture_shuffle_task_register(*tp);
779 return ret;
780 }
781 EXPORT_SYMBOL_GPL(_torture_create_kthread);
782
783 /*
784 * Stop a generic kthread, emitting a message.
785 */
_torture_stop_kthread(char * m,struct task_struct ** tp)786 void _torture_stop_kthread(char *m, struct task_struct **tp)
787 {
788 if (*tp == NULL)
789 return;
790 VERBOSE_TOROUT_STRING(m);
791 kthread_stop(*tp);
792 *tp = NULL;
793 }
794 EXPORT_SYMBOL_GPL(_torture_stop_kthread);
795
