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 "rcu/rcu.h"
41
42 MODULE_LICENSE("GPL");
43 MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>");
44
45 static char *torture_type;
46 static int verbose;
47
48 /* Mediate rmmod and system shutdown. Concurrent rmmod & shutdown illegal! */
49 #define FULLSTOP_DONTSTOP 0 /* Normal operation. */
50 #define FULLSTOP_SHUTDOWN 1 /* System shutdown with torture running. */
51 #define FULLSTOP_RMMOD 2 /* Normal rmmod of torture. */
52 static int fullstop = FULLSTOP_RMMOD;
53 static DEFINE_MUTEX(fullstop_mutex);
54
55 #ifdef CONFIG_HOTPLUG_CPU
56
57 /*
58 * Variables for online-offline handling. Only present if CPU hotplug
59 * is enabled, otherwise does nothing.
60 */
61
62 static struct task_struct *onoff_task;
63 static long onoff_holdoff;
64 static long onoff_interval;
65 static torture_ofl_func *onoff_f;
66 static long n_offline_attempts;
67 static long n_offline_successes;
68 static unsigned long sum_offline;
69 static int min_offline = -1;
70 static int max_offline;
71 static long n_online_attempts;
72 static long n_online_successes;
73 static unsigned long sum_online;
74 static int min_online = -1;
75 static int max_online;
76
77 /*
78 * Attempt to take a CPU offline. Return false if the CPU is already
79 * offline or if it is not subject to CPU-hotplug operations. The
80 * caller can detect other failures by looking at the statistics.
81 */
torture_offline(int cpu,long * n_offl_attempts,long * n_offl_successes,unsigned long * sum_offl,int * min_offl,int * max_offl)82 bool torture_offline(int cpu, long *n_offl_attempts, long *n_offl_successes,
83 unsigned long *sum_offl, int *min_offl, int *max_offl)
84 {
85 unsigned long delta;
86 int ret;
87 unsigned long starttime;
88
89 if (!cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
90 return false;
91 if (num_online_cpus() <= 1)
92 return false; /* Can't offline the last CPU. */
93
94 if (verbose > 1)
95 pr_alert("%s" TORTURE_FLAG
96 "torture_onoff task: offlining %d\n",
97 torture_type, cpu);
98 starttime = jiffies;
99 (*n_offl_attempts)++;
100 ret = cpu_down(cpu);
101 if (ret) {
102 if (verbose)
103 pr_alert("%s" TORTURE_FLAG
104 "torture_onoff task: offline %d failed: errno %d\n",
105 torture_type, cpu, ret);
106 } else {
107 if (verbose > 1)
108 pr_alert("%s" TORTURE_FLAG
109 "torture_onoff task: offlined %d\n",
110 torture_type, cpu);
111 if (onoff_f)
112 onoff_f();
113 (*n_offl_successes)++;
114 delta = jiffies - starttime;
115 *sum_offl += delta;
116 if (*min_offl < 0) {
117 *min_offl = delta;
118 *max_offl = delta;
119 }
120 if (*min_offl > delta)
121 *min_offl = delta;
122 if (*max_offl < delta)
123 *max_offl = delta;
124 }
125
126 return true;
127 }
128 EXPORT_SYMBOL_GPL(torture_offline);
129
130 /*
131 * Attempt to bring a CPU online. Return false if the CPU is already
132 * online or if it is not subject to CPU-hotplug operations. The
133 * caller can detect other failures by looking at the statistics.
134 */
torture_online(int cpu,long * n_onl_attempts,long * n_onl_successes,unsigned long * sum_onl,int * min_onl,int * max_onl)135 bool torture_online(int cpu, long *n_onl_attempts, long *n_onl_successes,
136 unsigned long *sum_onl, int *min_onl, int *max_onl)
137 {
138 unsigned long delta;
139 int ret;
140 unsigned long starttime;
141
142 if (cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
143 return false;
144
145 if (verbose > 1)
146 pr_alert("%s" TORTURE_FLAG
147 "torture_onoff task: onlining %d\n",
148 torture_type, cpu);
149 starttime = jiffies;
150 (*n_onl_attempts)++;
151 ret = cpu_up(cpu);
152 if (ret) {
153 if (verbose)
154 pr_alert("%s" TORTURE_FLAG
155 "torture_onoff task: online %d failed: errno %d\n",
156 torture_type, cpu, ret);
157 } else {
158 if (verbose > 1)
159 pr_alert("%s" TORTURE_FLAG
160 "torture_onoff task: onlined %d\n",
161 torture_type, cpu);
162 (*n_onl_successes)++;
163 delta = jiffies - starttime;
164 *sum_onl += delta;
165 if (*min_onl < 0) {
166 *min_onl = delta;
167 *max_onl = delta;
168 }
169 if (*min_onl > delta)
170 *min_onl = delta;
171 if (*max_onl < delta)
172 *max_onl = delta;
173 }
174
175 return true;
176 }
177 EXPORT_SYMBOL_GPL(torture_online);
178
179 /*
180 * Execute random CPU-hotplug operations at the interval specified
181 * by the onoff_interval.
182 */
183 static int
torture_onoff(void * arg)184 torture_onoff(void *arg)
185 {
186 int cpu;
187 int maxcpu = -1;
188 DEFINE_TORTURE_RANDOM(rand);
189 int ret;
190
191 VERBOSE_TOROUT_STRING("torture_onoff task started");
192 for_each_online_cpu(cpu)
193 maxcpu = cpu;
194 WARN_ON(maxcpu < 0);
195 if (!IS_MODULE(CONFIG_TORTURE_TEST))
196 for_each_possible_cpu(cpu) {
197 if (cpu_online(cpu))
198 continue;
199 ret = cpu_up(cpu);
200 if (ret && verbose) {
201 pr_alert("%s" TORTURE_FLAG
202 "%s: Initial online %d: errno %d\n",
203 __func__, torture_type, cpu, ret);
204 }
205 }
206
207 if (maxcpu == 0) {
208 VERBOSE_TOROUT_STRING("Only one CPU, so CPU-hotplug testing is disabled");
209 goto stop;
210 }
211
212 if (onoff_holdoff > 0) {
213 VERBOSE_TOROUT_STRING("torture_onoff begin holdoff");
214 schedule_timeout_interruptible(onoff_holdoff);
215 VERBOSE_TOROUT_STRING("torture_onoff end holdoff");
216 }
217 while (!torture_must_stop()) {
218 cpu = (torture_random(&rand) >> 4) % (maxcpu + 1);
219 if (!torture_offline(cpu,
220 &n_offline_attempts, &n_offline_successes,
221 &sum_offline, &min_offline, &max_offline))
222 torture_online(cpu,
223 &n_online_attempts, &n_online_successes,
224 &sum_online, &min_online, &max_online);
225 schedule_timeout_interruptible(onoff_interval);
226 }
227
228 stop:
229 torture_kthread_stopping("torture_onoff");
230 return 0;
231 }
232
233 #endif /* #ifdef CONFIG_HOTPLUG_CPU */
234
235 /*
236 * Initiate online-offline handling.
237 */
torture_onoff_init(long ooholdoff,long oointerval,torture_ofl_func * f)238 int torture_onoff_init(long ooholdoff, long oointerval, torture_ofl_func *f)
239 {
240 #ifdef CONFIG_HOTPLUG_CPU
241 onoff_holdoff = ooholdoff;
242 onoff_interval = oointerval;
243 onoff_f = f;
244 if (onoff_interval <= 0)
245 return 0;
246 return torture_create_kthread(torture_onoff, NULL, onoff_task);
247 #else /* #ifdef CONFIG_HOTPLUG_CPU */
248 return 0;
249 #endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
250 }
251 EXPORT_SYMBOL_GPL(torture_onoff_init);
252
253 /*
254 * Clean up after online/offline testing.
255 */
torture_onoff_cleanup(void)256 static void torture_onoff_cleanup(void)
257 {
258 #ifdef CONFIG_HOTPLUG_CPU
259 if (onoff_task == NULL)
260 return;
261 VERBOSE_TOROUT_STRING("Stopping torture_onoff task");
262 kthread_stop(onoff_task);
263 onoff_task = NULL;
264 #endif /* #ifdef CONFIG_HOTPLUG_CPU */
265 }
266
267 /*
268 * Print online/offline testing statistics.
269 */
torture_onoff_stats(void)270 void torture_onoff_stats(void)
271 {
272 #ifdef CONFIG_HOTPLUG_CPU
273 pr_cont("onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ",
274 n_online_successes, n_online_attempts,
275 n_offline_successes, n_offline_attempts,
276 min_online, max_online,
277 min_offline, max_offline,
278 sum_online, sum_offline, HZ);
279 #endif /* #ifdef CONFIG_HOTPLUG_CPU */
280 }
281 EXPORT_SYMBOL_GPL(torture_onoff_stats);
282
283 /*
284 * Were all the online/offline operations successful?
285 */
torture_onoff_failures(void)286 bool torture_onoff_failures(void)
287 {
288 #ifdef CONFIG_HOTPLUG_CPU
289 return n_online_successes != n_online_attempts ||
290 n_offline_successes != n_offline_attempts;
291 #else /* #ifdef CONFIG_HOTPLUG_CPU */
292 return false;
293 #endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
294 }
295 EXPORT_SYMBOL_GPL(torture_onoff_failures);
296
297 #define TORTURE_RANDOM_MULT 39916801 /* prime */
298 #define TORTURE_RANDOM_ADD 479001701 /* prime */
299 #define TORTURE_RANDOM_REFRESH 10000
300
301 /*
302 * Crude but fast random-number generator. Uses a linear congruential
303 * generator, with occasional help from cpu_clock().
304 */
305 unsigned long
torture_random(struct torture_random_state * trsp)306 torture_random(struct torture_random_state *trsp)
307 {
308 if (--trsp->trs_count < 0) {
309 trsp->trs_state += (unsigned long)local_clock();
310 trsp->trs_count = TORTURE_RANDOM_REFRESH;
311 }
312 trsp->trs_state = trsp->trs_state * TORTURE_RANDOM_MULT +
313 TORTURE_RANDOM_ADD;
314 return swahw32(trsp->trs_state);
315 }
316 EXPORT_SYMBOL_GPL(torture_random);
317
318 /*
319 * Variables for shuffling. The idea is to ensure that each CPU stays
320 * idle for an extended period to test interactions with dyntick idle,
321 * as well as interactions with any per-CPU variables.
322 */
323 struct shuffle_task {
324 struct list_head st_l;
325 struct task_struct *st_t;
326 };
327
328 static long shuffle_interval; /* In jiffies. */
329 static struct task_struct *shuffler_task;
330 static cpumask_var_t shuffle_tmp_mask;
331 static int shuffle_idle_cpu; /* Force all torture tasks off this CPU */
332 static struct list_head shuffle_task_list = LIST_HEAD_INIT(shuffle_task_list);
333 static DEFINE_MUTEX(shuffle_task_mutex);
334
335 /*
336 * Register a task to be shuffled. If there is no memory, just splat
337 * and don't bother registering.
338 */
torture_shuffle_task_register(struct task_struct * tp)339 void torture_shuffle_task_register(struct task_struct *tp)
340 {
341 struct shuffle_task *stp;
342
343 if (WARN_ON_ONCE(tp == NULL))
344 return;
345 stp = kmalloc(sizeof(*stp), GFP_KERNEL);
346 if (WARN_ON_ONCE(stp == NULL))
347 return;
348 stp->st_t = tp;
349 mutex_lock(&shuffle_task_mutex);
350 list_add(&stp->st_l, &shuffle_task_list);
351 mutex_unlock(&shuffle_task_mutex);
352 }
353 EXPORT_SYMBOL_GPL(torture_shuffle_task_register);
354
355 /*
356 * Unregister all tasks, for example, at the end of the torture run.
357 */
torture_shuffle_task_unregister_all(void)358 static void torture_shuffle_task_unregister_all(void)
359 {
360 struct shuffle_task *stp;
361 struct shuffle_task *p;
362
363 mutex_lock(&shuffle_task_mutex);
364 list_for_each_entry_safe(stp, p, &shuffle_task_list, st_l) {
365 list_del(&stp->st_l);
366 kfree(stp);
367 }
368 mutex_unlock(&shuffle_task_mutex);
369 }
370
371 /* Shuffle tasks such that we allow shuffle_idle_cpu to become idle.
372 * A special case is when shuffle_idle_cpu = -1, in which case we allow
373 * the tasks to run on all CPUs.
374 */
torture_shuffle_tasks(void)375 static void torture_shuffle_tasks(void)
376 {
377 struct shuffle_task *stp;
378
379 cpumask_setall(shuffle_tmp_mask);
380 get_online_cpus();
381
382 /* No point in shuffling if there is only one online CPU (ex: UP) */
383 if (num_online_cpus() == 1) {
384 put_online_cpus();
385 return;
386 }
387
388 /* Advance to the next CPU. Upon overflow, don't idle any CPUs. */
389 shuffle_idle_cpu = cpumask_next(shuffle_idle_cpu, shuffle_tmp_mask);
390 if (shuffle_idle_cpu >= nr_cpu_ids)
391 shuffle_idle_cpu = -1;
392 else
393 cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask);
394
395 mutex_lock(&shuffle_task_mutex);
396 list_for_each_entry(stp, &shuffle_task_list, st_l)
397 set_cpus_allowed_ptr(stp->st_t, shuffle_tmp_mask);
398 mutex_unlock(&shuffle_task_mutex);
399
400 put_online_cpus();
401 }
402
403 /* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
404 * system to become idle at a time and cut off its timer ticks. This is meant
405 * to test the support for such tickless idle CPU in RCU.
406 */
torture_shuffle(void * arg)407 static int torture_shuffle(void *arg)
408 {
409 VERBOSE_TOROUT_STRING("torture_shuffle task started");
410 do {
411 schedule_timeout_interruptible(shuffle_interval);
412 torture_shuffle_tasks();
413 torture_shutdown_absorb("torture_shuffle");
414 } while (!torture_must_stop());
415 torture_kthread_stopping("torture_shuffle");
416 return 0;
417 }
418
419 /*
420 * Start the shuffler, with shuffint in jiffies.
421 */
torture_shuffle_init(long shuffint)422 int torture_shuffle_init(long shuffint)
423 {
424 shuffle_interval = shuffint;
425
426 shuffle_idle_cpu = -1;
427
428 if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
429 VERBOSE_TOROUT_ERRSTRING("Failed to alloc mask");
430 return -ENOMEM;
431 }
432
433 /* Create the shuffler thread */
434 return torture_create_kthread(torture_shuffle, NULL, shuffler_task);
435 }
436 EXPORT_SYMBOL_GPL(torture_shuffle_init);
437
438 /*
439 * Stop the shuffling.
440 */
torture_shuffle_cleanup(void)441 static void torture_shuffle_cleanup(void)
442 {
443 torture_shuffle_task_unregister_all();
444 if (shuffler_task) {
445 VERBOSE_TOROUT_STRING("Stopping torture_shuffle task");
446 kthread_stop(shuffler_task);
447 free_cpumask_var(shuffle_tmp_mask);
448 }
449 shuffler_task = NULL;
450 }
451
452 /*
453 * Variables for auto-shutdown. This allows "lights out" torture runs
454 * to be fully scripted.
455 */
456 static struct task_struct *shutdown_task;
457 static ktime_t shutdown_time; /* time to system shutdown. */
458 static void (*torture_shutdown_hook)(void);
459
460 /*
461 * Absorb kthreads into a kernel function that won't return, so that
462 * they won't ever access module text or data again.
463 */
torture_shutdown_absorb(const char * title)464 void torture_shutdown_absorb(const char *title)
465 {
466 while (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
467 pr_notice("torture thread %s parking due to system shutdown\n",
468 title);
469 schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
470 }
471 }
472 EXPORT_SYMBOL_GPL(torture_shutdown_absorb);
473
474 /*
475 * Cause the torture test to shutdown the system after the test has
476 * run for the time specified by the shutdown_secs parameter.
477 */
torture_shutdown(void * arg)478 static int torture_shutdown(void *arg)
479 {
480 ktime_t ktime_snap;
481
482 VERBOSE_TOROUT_STRING("torture_shutdown task started");
483 ktime_snap = ktime_get();
484 while (ktime_before(ktime_snap, shutdown_time) &&
485 !torture_must_stop()) {
486 if (verbose)
487 pr_alert("%s" TORTURE_FLAG
488 "torture_shutdown task: %llu ms remaining\n",
489 torture_type,
490 ktime_ms_delta(shutdown_time, ktime_snap));
491 set_current_state(TASK_INTERRUPTIBLE);
492 schedule_hrtimeout(&shutdown_time, HRTIMER_MODE_ABS);
493 ktime_snap = ktime_get();
494 }
495 if (torture_must_stop()) {
496 torture_kthread_stopping("torture_shutdown");
497 return 0;
498 }
499
500 /* OK, shut down the system. */
501
502 VERBOSE_TOROUT_STRING("torture_shutdown task shutting down system");
503 shutdown_task = NULL; /* Avoid self-kill deadlock. */
504 if (torture_shutdown_hook)
505 torture_shutdown_hook();
506 else
507 VERBOSE_TOROUT_STRING("No torture_shutdown_hook(), skipping.");
508 rcu_ftrace_dump(DUMP_ALL);
509 kernel_power_off(); /* Shut down the system. */
510 return 0;
511 }
512
513 /*
514 * Start up the shutdown task.
515 */
torture_shutdown_init(int ssecs,void (* cleanup)(void))516 int torture_shutdown_init(int ssecs, void (*cleanup)(void))
517 {
518 torture_shutdown_hook = cleanup;
519 if (ssecs > 0) {
520 shutdown_time = ktime_add(ktime_get(), ktime_set(ssecs, 0));
521 return torture_create_kthread(torture_shutdown, NULL,
522 shutdown_task);
523 }
524 return 0;
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 static int stutter_gap;
572
573 /*
574 * Block until the stutter interval ends. This must be called periodically
575 * by all running kthreads that need to be subject to stuttering.
576 */
stutter_wait(const char * title)577 bool stutter_wait(const char *title)
578 {
579 int spt;
580 bool ret = false;
581
582 cond_resched_tasks_rcu_qs();
583 spt = READ_ONCE(stutter_pause_test);
584 for (; spt; spt = READ_ONCE(stutter_pause_test)) {
585 ret = true;
586 if (spt == 1) {
587 schedule_timeout_interruptible(1);
588 } else if (spt == 2) {
589 while (READ_ONCE(stutter_pause_test))
590 cond_resched();
591 } else {
592 schedule_timeout_interruptible(round_jiffies_relative(HZ));
593 }
594 torture_shutdown_absorb(title);
595 }
596 return ret;
597 }
598 EXPORT_SYMBOL_GPL(stutter_wait);
599
600 /*
601 * Cause the torture test to "stutter", starting and stopping all
602 * threads periodically.
603 */
torture_stutter(void * arg)604 static int torture_stutter(void *arg)
605 {
606 int wtime;
607
608 VERBOSE_TOROUT_STRING("torture_stutter task started");
609 do {
610 if (!torture_must_stop() && stutter > 1) {
611 wtime = stutter;
612 if (stutter > HZ + 1) {
613 WRITE_ONCE(stutter_pause_test, 1);
614 wtime = stutter - HZ - 1;
615 schedule_timeout_interruptible(wtime);
616 wtime = HZ + 1;
617 }
618 WRITE_ONCE(stutter_pause_test, 2);
619 schedule_timeout_interruptible(wtime);
620 }
621 WRITE_ONCE(stutter_pause_test, 0);
622 if (!torture_must_stop())
623 schedule_timeout_interruptible(stutter_gap);
624 torture_shutdown_absorb("torture_stutter");
625 } while (!torture_must_stop());
626 torture_kthread_stopping("torture_stutter");
627 return 0;
628 }
629
630 /*
631 * Initialize and kick off the torture_stutter kthread.
632 */
torture_stutter_init(const int s,const int sgap)633 int torture_stutter_init(const int s, const int sgap)
634 {
635 stutter = s;
636 stutter_gap = sgap;
637 return torture_create_kthread(torture_stutter, NULL, stutter_task);
638 }
639 EXPORT_SYMBOL_GPL(torture_stutter_init);
640
641 /*
642 * Cleanup after the torture_stutter kthread.
643 */
torture_stutter_cleanup(void)644 static void torture_stutter_cleanup(void)
645 {
646 if (!stutter_task)
647 return;
648 VERBOSE_TOROUT_STRING("Stopping torture_stutter task");
649 kthread_stop(stutter_task);
650 stutter_task = NULL;
651 }
652
653 /*
654 * Initialize torture module. Please note that this is -not- invoked via
655 * the usual module_init() mechanism, but rather by an explicit call from
656 * the client torture module. This call must be paired with a later
657 * torture_init_end().
658 *
659 * The runnable parameter points to a flag that controls whether or not
660 * the test is currently runnable. If there is no such flag, pass in NULL.
661 */
torture_init_begin(char * ttype,int v)662 bool torture_init_begin(char *ttype, int v)
663 {
664 mutex_lock(&fullstop_mutex);
665 if (torture_type != NULL) {
666 pr_alert("torture_init_begin: Refusing %s init: %s running.\n",
667 ttype, torture_type);
668 pr_alert("torture_init_begin: One torture test at a time!\n");
669 mutex_unlock(&fullstop_mutex);
670 return false;
671 }
672 torture_type = ttype;
673 verbose = v;
674 fullstop = FULLSTOP_DONTSTOP;
675 return true;
676 }
677 EXPORT_SYMBOL_GPL(torture_init_begin);
678
679 /*
680 * Tell the torture module that initialization is complete.
681 */
torture_init_end(void)682 void torture_init_end(void)
683 {
684 mutex_unlock(&fullstop_mutex);
685 register_reboot_notifier(&torture_shutdown_nb);
686 }
687 EXPORT_SYMBOL_GPL(torture_init_end);
688
689 /*
690 * Clean up torture module. Please note that this is -not- invoked via
691 * the usual module_exit() mechanism, but rather by an explicit call from
692 * the client torture module. Returns true if a race with system shutdown
693 * is detected, otherwise, all kthreads started by functions in this file
694 * will be shut down.
695 *
696 * This must be called before the caller starts shutting down its own
697 * kthreads.
698 *
699 * Both torture_cleanup_begin() and torture_cleanup_end() must be paired,
700 * in order to correctly perform the cleanup. They are separated because
701 * threads can still need to reference the torture_type type, thus nullify
702 * only after completing all other relevant calls.
703 */
torture_cleanup_begin(void)704 bool torture_cleanup_begin(void)
705 {
706 mutex_lock(&fullstop_mutex);
707 if (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
708 pr_warn("Concurrent rmmod and shutdown illegal!\n");
709 mutex_unlock(&fullstop_mutex);
710 schedule_timeout_uninterruptible(10);
711 return true;
712 }
713 WRITE_ONCE(fullstop, FULLSTOP_RMMOD);
714 mutex_unlock(&fullstop_mutex);
715 torture_shutdown_cleanup();
716 torture_shuffle_cleanup();
717 torture_stutter_cleanup();
718 torture_onoff_cleanup();
719 return false;
720 }
721 EXPORT_SYMBOL_GPL(torture_cleanup_begin);
722
torture_cleanup_end(void)723 void torture_cleanup_end(void)
724 {
725 mutex_lock(&fullstop_mutex);
726 torture_type = NULL;
727 mutex_unlock(&fullstop_mutex);
728 }
729 EXPORT_SYMBOL_GPL(torture_cleanup_end);
730
731 /*
732 * Is it time for the current torture test to stop?
733 */
torture_must_stop(void)734 bool torture_must_stop(void)
735 {
736 return torture_must_stop_irq() || kthread_should_stop();
737 }
738 EXPORT_SYMBOL_GPL(torture_must_stop);
739
740 /*
741 * Is it time for the current torture test to stop? This is the irq-safe
742 * version, hence no check for kthread_should_stop().
743 */
torture_must_stop_irq(void)744 bool torture_must_stop_irq(void)
745 {
746 return READ_ONCE(fullstop) != FULLSTOP_DONTSTOP;
747 }
748 EXPORT_SYMBOL_GPL(torture_must_stop_irq);
749
750 /*
751 * Each kthread must wait for kthread_should_stop() before returning from
752 * its top-level function, otherwise segfaults ensue. This function
753 * prints a "stopping" message and waits for kthread_should_stop(), and
754 * should be called from all torture kthreads immediately prior to
755 * returning.
756 */
torture_kthread_stopping(char * title)757 void torture_kthread_stopping(char *title)
758 {
759 char buf[128];
760
761 snprintf(buf, sizeof(buf), "Stopping %s", title);
762 VERBOSE_TOROUT_STRING(buf);
763 while (!kthread_should_stop()) {
764 torture_shutdown_absorb(title);
765 schedule_timeout_uninterruptible(1);
766 }
767 }
768 EXPORT_SYMBOL_GPL(torture_kthread_stopping);
769
770 /*
771 * Create a generic torture kthread that is immediately runnable. If you
772 * need the kthread to be stopped so that you can do something to it before
773 * it starts, you will need to open-code your own.
774 */
_torture_create_kthread(int (* fn)(void * arg),void * arg,char * s,char * m,char * f,struct task_struct ** tp)775 int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
776 char *f, struct task_struct **tp)
777 {
778 int ret = 0;
779
780 VERBOSE_TOROUT_STRING(m);
781 *tp = kthread_run(fn, arg, "%s", s);
782 if (IS_ERR(*tp)) {
783 ret = PTR_ERR(*tp);
784 VERBOSE_TOROUT_ERRSTRING(f);
785 *tp = NULL;
786 }
787 torture_shuffle_task_register(*tp);
788 return ret;
789 }
790 EXPORT_SYMBOL_GPL(_torture_create_kthread);
791
792 /*
793 * Stop a generic kthread, emitting a message.
794 */
_torture_stop_kthread(char * m,struct task_struct ** tp)795 void _torture_stop_kthread(char *m, struct task_struct **tp)
796 {
797 if (*tp == NULL)
798 return;
799 VERBOSE_TOROUT_STRING(m);
800 kthread_stop(*tp);
801 *tp = NULL;
802 }
803 EXPORT_SYMBOL_GPL(_torture_stop_kthread);
804