blob: 0d887eb62856e38761aa840ab22347cdc98c1c90
1 | /* |
2 | * Common functions for in-kernel torture tests. |
3 | * |
4 | * This program is free software; you can redistribute it and/or modify |
5 | * it under the terms of the GNU General Public License as published by |
6 | * the Free Software Foundation; either version 2 of the License, or |
7 | * (at your option) any later version. |
8 | * |
9 | * This program is distributed in the hope that it will be useful, |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
12 | * GNU General Public License for more details. |
13 | * |
14 | * You should have received a copy of the GNU General Public License |
15 | * along with this program; if not, you can access it online at |
16 | * http://www.gnu.org/licenses/gpl-2.0.html. |
17 | * |
18 | * Copyright (C) IBM Corporation, 2014 |
19 | * |
20 | * Author: Paul E. McKenney <paulmck@us.ibm.com> |
21 | * Based on kernel/rcu/torture.c. |
22 | */ |
23 | #include <linux/types.h> |
24 | #include <linux/kernel.h> |
25 | #include <linux/init.h> |
26 | #include <linux/module.h> |
27 | #include <linux/kthread.h> |
28 | #include <linux/err.h> |
29 | #include <linux/spinlock.h> |
30 | #include <linux/smp.h> |
31 | #include <linux/interrupt.h> |
32 | #include <linux/sched.h> |
33 | #include <linux/atomic.h> |
34 | #include <linux/bitops.h> |
35 | #include <linux/completion.h> |
36 | #include <linux/moduleparam.h> |
37 | #include <linux/percpu.h> |
38 | #include <linux/notifier.h> |
39 | #include <linux/reboot.h> |
40 | #include <linux/freezer.h> |
41 | #include <linux/cpu.h> |
42 | #include <linux/delay.h> |
43 | #include <linux/stat.h> |
44 | #include <linux/slab.h> |
45 | #include <linux/trace_clock.h> |
46 | #include <linux/ktime.h> |
47 | #include <asm/byteorder.h> |
48 | #include <linux/torture.h> |
49 | |
50 | MODULE_LICENSE("GPL"); |
51 | MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>"); |
52 | |
53 | static char *torture_type; |
54 | static bool verbose; |
55 | |
56 | /* Mediate rmmod and system shutdown. Concurrent rmmod & shutdown illegal! */ |
57 | #define FULLSTOP_DONTSTOP 0 /* Normal operation. */ |
58 | #define FULLSTOP_SHUTDOWN 1 /* System shutdown with torture running. */ |
59 | #define FULLSTOP_RMMOD 2 /* Normal rmmod of torture. */ |
60 | static int fullstop = FULLSTOP_RMMOD; |
61 | static DEFINE_MUTEX(fullstop_mutex); |
62 | static int *torture_runnable; |
63 | |
64 | #ifdef CONFIG_HOTPLUG_CPU |
65 | |
66 | /* |
67 | * Variables for online-offline handling. Only present if CPU hotplug |
68 | * is enabled, otherwise does nothing. |
69 | */ |
70 | |
71 | static struct task_struct *onoff_task; |
72 | static long onoff_holdoff; |
73 | static long onoff_interval; |
74 | static long n_offline_attempts; |
75 | static long n_offline_successes; |
76 | static unsigned long sum_offline; |
77 | static int min_offline = -1; |
78 | static int max_offline; |
79 | static long n_online_attempts; |
80 | static long n_online_successes; |
81 | static unsigned long sum_online; |
82 | static int min_online = -1; |
83 | static int max_online; |
84 | |
85 | /* |
86 | * Attempt to take a CPU offline. Return false if the CPU is already |
87 | * offline or if it is not subject to CPU-hotplug operations. The |
88 | * caller can detect other failures by looking at the statistics. |
89 | */ |
90 | bool torture_offline(int cpu, long *n_offl_attempts, long *n_offl_successes, |
91 | unsigned long *sum_offl, int *min_offl, int *max_offl) |
92 | { |
93 | unsigned long delta; |
94 | int ret; |
95 | unsigned long starttime; |
96 | |
97 | if (!cpu_online(cpu) || !cpu_is_hotpluggable(cpu)) |
98 | return false; |
99 | |
100 | if (verbose) |
101 | pr_alert("%s" TORTURE_FLAG |
102 | "torture_onoff task: offlining %d\n", |
103 | torture_type, cpu); |
104 | starttime = jiffies; |
105 | (*n_offl_attempts)++; |
106 | ret = cpu_down(cpu); |
107 | if (ret) { |
108 | if (verbose) |
109 | pr_alert("%s" TORTURE_FLAG |
110 | "torture_onoff task: offline %d failed: errno %d\n", |
111 | torture_type, cpu, ret); |
112 | } else { |
113 | if (verbose) |
114 | pr_alert("%s" TORTURE_FLAG |
115 | "torture_onoff task: offlined %d\n", |
116 | torture_type, cpu); |
117 | (*n_offl_successes)++; |
118 | delta = jiffies - starttime; |
119 | sum_offl += delta; |
120 | if (*min_offl < 0) { |
121 | *min_offl = delta; |
122 | *max_offl = delta; |
123 | } |
124 | if (*min_offl > delta) |
125 | *min_offl = delta; |
126 | if (*max_offl < delta) |
127 | *max_offl = delta; |
128 | } |
129 | |
130 | return true; |
131 | } |
132 | EXPORT_SYMBOL_GPL(torture_offline); |
133 | |
134 | /* |
135 | * Attempt to bring a CPU online. Return false if the CPU is already |
136 | * online or if it is not subject to CPU-hotplug operations. The |
137 | * caller can detect other failures by looking at the statistics. |
138 | */ |
139 | bool torture_online(int cpu, long *n_onl_attempts, long *n_onl_successes, |
140 | unsigned long *sum_onl, int *min_onl, int *max_onl) |
141 | { |
142 | unsigned long delta; |
143 | int ret; |
144 | unsigned long starttime; |
145 | |
146 | if (cpu_online(cpu) || !cpu_is_hotpluggable(cpu)) |
147 | return false; |
148 | |
149 | if (verbose) |
150 | pr_alert("%s" TORTURE_FLAG |
151 | "torture_onoff task: onlining %d\n", |
152 | torture_type, cpu); |
153 | starttime = jiffies; |
154 | (*n_onl_attempts)++; |
155 | ret = cpu_up(cpu); |
156 | if (ret) { |
157 | if (verbose) |
158 | pr_alert("%s" TORTURE_FLAG |
159 | "torture_onoff task: online %d failed: errno %d\n", |
160 | torture_type, cpu, ret); |
161 | } else { |
162 | if (verbose) |
163 | pr_alert("%s" TORTURE_FLAG |
164 | "torture_onoff task: onlined %d\n", |
165 | torture_type, cpu); |
166 | (*n_onl_successes)++; |
167 | delta = jiffies - starttime; |
168 | *sum_onl += delta; |
169 | if (*min_onl < 0) { |
170 | *min_onl = delta; |
171 | *max_onl = delta; |
172 | } |
173 | if (*min_onl > delta) |
174 | *min_onl = delta; |
175 | if (*max_onl < delta) |
176 | *max_onl = delta; |
177 | } |
178 | |
179 | return true; |
180 | } |
181 | EXPORT_SYMBOL_GPL(torture_online); |
182 | |
183 | /* |
184 | * Execute random CPU-hotplug operations at the interval specified |
185 | * by the onoff_interval. |
186 | */ |
187 | static int |
188 | torture_onoff(void *arg) |
189 | { |
190 | int cpu; |
191 | int maxcpu = -1; |
192 | DEFINE_TORTURE_RANDOM(rand); |
193 | |
194 | VERBOSE_TOROUT_STRING("torture_onoff task started"); |
195 | for_each_online_cpu(cpu) |
196 | maxcpu = cpu; |
197 | WARN_ON(maxcpu < 0); |
198 | |
199 | if (maxcpu == 0) { |
200 | VERBOSE_TOROUT_STRING("Only one CPU, so CPU-hotplug testing is disabled"); |
201 | goto stop; |
202 | } |
203 | |
204 | if (onoff_holdoff > 0) { |
205 | VERBOSE_TOROUT_STRING("torture_onoff begin holdoff"); |
206 | schedule_timeout_interruptible(onoff_holdoff); |
207 | VERBOSE_TOROUT_STRING("torture_onoff end holdoff"); |
208 | } |
209 | while (!torture_must_stop()) { |
210 | cpu = (torture_random(&rand) >> 4) % (maxcpu + 1); |
211 | if (!torture_offline(cpu, |
212 | &n_offline_attempts, &n_offline_successes, |
213 | &sum_offline, &min_offline, &max_offline)) |
214 | torture_online(cpu, |
215 | &n_online_attempts, &n_online_successes, |
216 | &sum_online, &min_online, &max_online); |
217 | schedule_timeout_interruptible(onoff_interval); |
218 | } |
219 | |
220 | stop: |
221 | torture_kthread_stopping("torture_onoff"); |
222 | return 0; |
223 | } |
224 | |
225 | #endif /* #ifdef CONFIG_HOTPLUG_CPU */ |
226 | |
227 | /* |
228 | * Initiate online-offline handling. |
229 | */ |
230 | int torture_onoff_init(long ooholdoff, long oointerval) |
231 | { |
232 | int ret = 0; |
233 | |
234 | #ifdef CONFIG_HOTPLUG_CPU |
235 | onoff_holdoff = ooholdoff; |
236 | onoff_interval = oointerval; |
237 | if (onoff_interval <= 0) |
238 | return 0; |
239 | ret = torture_create_kthread(torture_onoff, NULL, onoff_task); |
240 | #endif /* #ifdef CONFIG_HOTPLUG_CPU */ |
241 | return ret; |
242 | } |
243 | EXPORT_SYMBOL_GPL(torture_onoff_init); |
244 | |
245 | /* |
246 | * Clean up after online/offline testing. |
247 | */ |
248 | static void torture_onoff_cleanup(void) |
249 | { |
250 | #ifdef CONFIG_HOTPLUG_CPU |
251 | if (onoff_task == NULL) |
252 | return; |
253 | VERBOSE_TOROUT_STRING("Stopping torture_onoff task"); |
254 | kthread_stop(onoff_task); |
255 | onoff_task = NULL; |
256 | #endif /* #ifdef CONFIG_HOTPLUG_CPU */ |
257 | } |
258 | EXPORT_SYMBOL_GPL(torture_onoff_cleanup); |
259 | |
260 | /* |
261 | * Print online/offline testing statistics. |
262 | */ |
263 | void torture_onoff_stats(void) |
264 | { |
265 | #ifdef CONFIG_HOTPLUG_CPU |
266 | pr_cont("onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ", |
267 | n_online_successes, n_online_attempts, |
268 | n_offline_successes, n_offline_attempts, |
269 | min_online, max_online, |
270 | min_offline, max_offline, |
271 | sum_online, sum_offline, HZ); |
272 | #endif /* #ifdef CONFIG_HOTPLUG_CPU */ |
273 | } |
274 | EXPORT_SYMBOL_GPL(torture_onoff_stats); |
275 | |
276 | /* |
277 | * Were all the online/offline operations successful? |
278 | */ |
279 | bool torture_onoff_failures(void) |
280 | { |
281 | #ifdef CONFIG_HOTPLUG_CPU |
282 | return n_online_successes != n_online_attempts || |
283 | n_offline_successes != n_offline_attempts; |
284 | #else /* #ifdef CONFIG_HOTPLUG_CPU */ |
285 | return false; |
286 | #endif /* #else #ifdef CONFIG_HOTPLUG_CPU */ |
287 | } |
288 | EXPORT_SYMBOL_GPL(torture_onoff_failures); |
289 | |
290 | #define TORTURE_RANDOM_MULT 39916801 /* prime */ |
291 | #define TORTURE_RANDOM_ADD 479001701 /* prime */ |
292 | #define TORTURE_RANDOM_REFRESH 10000 |
293 | |
294 | /* |
295 | * Crude but fast random-number generator. Uses a linear congruential |
296 | * generator, with occasional help from cpu_clock(). |
297 | */ |
298 | unsigned long |
299 | torture_random(struct torture_random_state *trsp) |
300 | { |
301 | if (--trsp->trs_count < 0) { |
302 | trsp->trs_state += (unsigned long)local_clock(); |
303 | trsp->trs_count = TORTURE_RANDOM_REFRESH; |
304 | } |
305 | trsp->trs_state = trsp->trs_state * TORTURE_RANDOM_MULT + |
306 | TORTURE_RANDOM_ADD; |
307 | return swahw32(trsp->trs_state); |
308 | } |
309 | EXPORT_SYMBOL_GPL(torture_random); |
310 | |
311 | /* |
312 | * Variables for shuffling. The idea is to ensure that each CPU stays |
313 | * idle for an extended period to test interactions with dyntick idle, |
314 | * as well as interactions with any per-CPU varibles. |
315 | */ |
316 | struct shuffle_task { |
317 | struct list_head st_l; |
318 | struct task_struct *st_t; |
319 | }; |
320 | |
321 | static long shuffle_interval; /* In jiffies. */ |
322 | static struct task_struct *shuffler_task; |
323 | static cpumask_var_t shuffle_tmp_mask; |
324 | static int shuffle_idle_cpu; /* Force all torture tasks off this CPU */ |
325 | static struct list_head shuffle_task_list = LIST_HEAD_INIT(shuffle_task_list); |
326 | static DEFINE_MUTEX(shuffle_task_mutex); |
327 | |
328 | /* |
329 | * Register a task to be shuffled. If there is no memory, just splat |
330 | * and don't bother registering. |
331 | */ |
332 | void torture_shuffle_task_register(struct task_struct *tp) |
333 | { |
334 | struct shuffle_task *stp; |
335 | |
336 | if (WARN_ON_ONCE(tp == NULL)) |
337 | return; |
338 | stp = kmalloc(sizeof(*stp), GFP_KERNEL); |
339 | if (WARN_ON_ONCE(stp == NULL)) |
340 | return; |
341 | stp->st_t = tp; |
342 | mutex_lock(&shuffle_task_mutex); |
343 | list_add(&stp->st_l, &shuffle_task_list); |
344 | mutex_unlock(&shuffle_task_mutex); |
345 | } |
346 | EXPORT_SYMBOL_GPL(torture_shuffle_task_register); |
347 | |
348 | /* |
349 | * Unregister all tasks, for example, at the end of the torture run. |
350 | */ |
351 | static void torture_shuffle_task_unregister_all(void) |
352 | { |
353 | struct shuffle_task *stp; |
354 | struct shuffle_task *p; |
355 | |
356 | mutex_lock(&shuffle_task_mutex); |
357 | list_for_each_entry_safe(stp, p, &shuffle_task_list, st_l) { |
358 | list_del(&stp->st_l); |
359 | kfree(stp); |
360 | } |
361 | mutex_unlock(&shuffle_task_mutex); |
362 | } |
363 | |
364 | /* Shuffle tasks such that we allow shuffle_idle_cpu to become idle. |
365 | * A special case is when shuffle_idle_cpu = -1, in which case we allow |
366 | * the tasks to run on all CPUs. |
367 | */ |
368 | static void torture_shuffle_tasks(void) |
369 | { |
370 | struct shuffle_task *stp; |
371 | |
372 | cpumask_setall(shuffle_tmp_mask); |
373 | get_online_cpus(); |
374 | |
375 | /* No point in shuffling if there is only one online CPU (ex: UP) */ |
376 | if (num_online_cpus() == 1) { |
377 | put_online_cpus(); |
378 | return; |
379 | } |
380 | |
381 | /* Advance to the next CPU. Upon overflow, don't idle any CPUs. */ |
382 | shuffle_idle_cpu = cpumask_next(shuffle_idle_cpu, shuffle_tmp_mask); |
383 | if (shuffle_idle_cpu >= nr_cpu_ids) |
384 | shuffle_idle_cpu = -1; |
385 | else |
386 | cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask); |
387 | |
388 | mutex_lock(&shuffle_task_mutex); |
389 | list_for_each_entry(stp, &shuffle_task_list, st_l) |
390 | set_cpus_allowed_ptr(stp->st_t, shuffle_tmp_mask); |
391 | mutex_unlock(&shuffle_task_mutex); |
392 | |
393 | put_online_cpus(); |
394 | } |
395 | |
396 | /* Shuffle tasks across CPUs, with the intent of allowing each CPU in the |
397 | * system to become idle at a time and cut off its timer ticks. This is meant |
398 | * to test the support for such tickless idle CPU in RCU. |
399 | */ |
400 | static int torture_shuffle(void *arg) |
401 | { |
402 | VERBOSE_TOROUT_STRING("torture_shuffle task started"); |
403 | do { |
404 | schedule_timeout_interruptible(shuffle_interval); |
405 | torture_shuffle_tasks(); |
406 | torture_shutdown_absorb("torture_shuffle"); |
407 | } while (!torture_must_stop()); |
408 | torture_kthread_stopping("torture_shuffle"); |
409 | return 0; |
410 | } |
411 | |
412 | /* |
413 | * Start the shuffler, with shuffint in jiffies. |
414 | */ |
415 | int torture_shuffle_init(long shuffint) |
416 | { |
417 | shuffle_interval = shuffint; |
418 | |
419 | shuffle_idle_cpu = -1; |
420 | |
421 | if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) { |
422 | VERBOSE_TOROUT_ERRSTRING("Failed to alloc mask"); |
423 | return -ENOMEM; |
424 | } |
425 | |
426 | /* Create the shuffler thread */ |
427 | return torture_create_kthread(torture_shuffle, NULL, shuffler_task); |
428 | } |
429 | EXPORT_SYMBOL_GPL(torture_shuffle_init); |
430 | |
431 | /* |
432 | * Stop the shuffling. |
433 | */ |
434 | static void torture_shuffle_cleanup(void) |
435 | { |
436 | torture_shuffle_task_unregister_all(); |
437 | if (shuffler_task) { |
438 | VERBOSE_TOROUT_STRING("Stopping torture_shuffle task"); |
439 | kthread_stop(shuffler_task); |
440 | free_cpumask_var(shuffle_tmp_mask); |
441 | } |
442 | shuffler_task = NULL; |
443 | } |
444 | EXPORT_SYMBOL_GPL(torture_shuffle_cleanup); |
445 | |
446 | /* |
447 | * Variables for auto-shutdown. This allows "lights out" torture runs |
448 | * to be fully scripted. |
449 | */ |
450 | static struct task_struct *shutdown_task; |
451 | static ktime_t shutdown_time; /* time to system shutdown. */ |
452 | static void (*torture_shutdown_hook)(void); |
453 | |
454 | /* |
455 | * Absorb kthreads into a kernel function that won't return, so that |
456 | * they won't ever access module text or data again. |
457 | */ |
458 | void torture_shutdown_absorb(const char *title) |
459 | { |
460 | while (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) { |
461 | pr_notice("torture thread %s parking due to system shutdown\n", |
462 | title); |
463 | schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT); |
464 | } |
465 | } |
466 | EXPORT_SYMBOL_GPL(torture_shutdown_absorb); |
467 | |
468 | /* |
469 | * Cause the torture test to shutdown the system after the test has |
470 | * run for the time specified by the shutdown_secs parameter. |
471 | */ |
472 | static int torture_shutdown(void *arg) |
473 | { |
474 | ktime_t ktime_snap; |
475 | |
476 | VERBOSE_TOROUT_STRING("torture_shutdown task started"); |
477 | ktime_snap = ktime_get(); |
478 | while (ktime_before(ktime_snap, shutdown_time) && |
479 | !torture_must_stop()) { |
480 | if (verbose) |
481 | pr_alert("%s" TORTURE_FLAG |
482 | "torture_shutdown task: %llu ms remaining\n", |
483 | torture_type, |
484 | ktime_ms_delta(shutdown_time, ktime_snap)); |
485 | set_current_state(TASK_INTERRUPTIBLE); |
486 | schedule_hrtimeout(&shutdown_time, HRTIMER_MODE_ABS); |
487 | ktime_snap = ktime_get(); |
488 | } |
489 | if (torture_must_stop()) { |
490 | torture_kthread_stopping("torture_shutdown"); |
491 | return 0; |
492 | } |
493 | |
494 | /* OK, shut down the system. */ |
495 | |
496 | VERBOSE_TOROUT_STRING("torture_shutdown task shutting down system"); |
497 | shutdown_task = NULL; /* Avoid self-kill deadlock. */ |
498 | if (torture_shutdown_hook) |
499 | torture_shutdown_hook(); |
500 | else |
501 | VERBOSE_TOROUT_STRING("No torture_shutdown_hook(), skipping."); |
502 | ftrace_dump(DUMP_ALL); |
503 | kernel_power_off(); /* Shut down the system. */ |
504 | return 0; |
505 | } |
506 | |
507 | /* |
508 | * Start up the shutdown task. |
509 | */ |
510 | int torture_shutdown_init(int ssecs, void (*cleanup)(void)) |
511 | { |
512 | int ret = 0; |
513 | |
514 | torture_shutdown_hook = cleanup; |
515 | if (ssecs > 0) { |
516 | shutdown_time = ktime_add(ktime_get(), ktime_set(ssecs, 0)); |
517 | ret = torture_create_kthread(torture_shutdown, NULL, |
518 | shutdown_task); |
519 | } |
520 | return ret; |
521 | } |
522 | EXPORT_SYMBOL_GPL(torture_shutdown_init); |
523 | |
524 | /* |
525 | * Detect and respond to a system shutdown. |
526 | */ |
527 | static int torture_shutdown_notify(struct notifier_block *unused1, |
528 | unsigned long unused2, void *unused3) |
529 | { |
530 | mutex_lock(&fullstop_mutex); |
531 | if (READ_ONCE(fullstop) == FULLSTOP_DONTSTOP) { |
532 | VERBOSE_TOROUT_STRING("Unscheduled system shutdown detected"); |
533 | WRITE_ONCE(fullstop, FULLSTOP_SHUTDOWN); |
534 | } else { |
535 | pr_warn("Concurrent rmmod and shutdown illegal!\n"); |
536 | } |
537 | mutex_unlock(&fullstop_mutex); |
538 | return NOTIFY_DONE; |
539 | } |
540 | |
541 | static struct notifier_block torture_shutdown_nb = { |
542 | .notifier_call = torture_shutdown_notify, |
543 | }; |
544 | |
545 | /* |
546 | * Shut down the shutdown task. Say what??? Heh! This can happen if |
547 | * the torture module gets an rmmod before the shutdown time arrives. ;-) |
548 | */ |
549 | static void torture_shutdown_cleanup(void) |
550 | { |
551 | unregister_reboot_notifier(&torture_shutdown_nb); |
552 | if (shutdown_task != NULL) { |
553 | VERBOSE_TOROUT_STRING("Stopping torture_shutdown task"); |
554 | kthread_stop(shutdown_task); |
555 | } |
556 | shutdown_task = NULL; |
557 | } |
558 | |
559 | /* |
560 | * Variables for stuttering, which means to periodically pause and |
561 | * restart testing in order to catch bugs that appear when load is |
562 | * suddenly applied to or removed from the system. |
563 | */ |
564 | static struct task_struct *stutter_task; |
565 | static int stutter_pause_test; |
566 | static int stutter; |
567 | |
568 | /* |
569 | * Block until the stutter interval ends. This must be called periodically |
570 | * by all running kthreads that need to be subject to stuttering. |
571 | */ |
572 | void stutter_wait(const char *title) |
573 | { |
574 | cond_resched_rcu_qs(); |
575 | while (READ_ONCE(stutter_pause_test) || |
576 | (torture_runnable && !READ_ONCE(*torture_runnable))) { |
577 | if (stutter_pause_test) |
578 | if (READ_ONCE(stutter_pause_test) == 1) |
579 | schedule_timeout_interruptible(1); |
580 | else |
581 | while (READ_ONCE(stutter_pause_test)) |
582 | cond_resched(); |
583 | else |
584 | schedule_timeout_interruptible(round_jiffies_relative(HZ)); |
585 | torture_shutdown_absorb(title); |
586 | } |
587 | } |
588 | EXPORT_SYMBOL_GPL(stutter_wait); |
589 | |
590 | /* |
591 | * Cause the torture test to "stutter", starting and stopping all |
592 | * threads periodically. |
593 | */ |
594 | static int torture_stutter(void *arg) |
595 | { |
596 | VERBOSE_TOROUT_STRING("torture_stutter task started"); |
597 | do { |
598 | if (!torture_must_stop()) { |
599 | if (stutter > 1) { |
600 | schedule_timeout_interruptible(stutter - 1); |
601 | WRITE_ONCE(stutter_pause_test, 2); |
602 | } |
603 | schedule_timeout_interruptible(1); |
604 | WRITE_ONCE(stutter_pause_test, 1); |
605 | } |
606 | if (!torture_must_stop()) |
607 | schedule_timeout_interruptible(stutter); |
608 | WRITE_ONCE(stutter_pause_test, 0); |
609 | torture_shutdown_absorb("torture_stutter"); |
610 | } while (!torture_must_stop()); |
611 | torture_kthread_stopping("torture_stutter"); |
612 | return 0; |
613 | } |
614 | |
615 | /* |
616 | * Initialize and kick off the torture_stutter kthread. |
617 | */ |
618 | int torture_stutter_init(int s) |
619 | { |
620 | int ret; |
621 | |
622 | stutter = s; |
623 | ret = torture_create_kthread(torture_stutter, NULL, stutter_task); |
624 | return ret; |
625 | } |
626 | EXPORT_SYMBOL_GPL(torture_stutter_init); |
627 | |
628 | /* |
629 | * Cleanup after the torture_stutter kthread. |
630 | */ |
631 | static void torture_stutter_cleanup(void) |
632 | { |
633 | if (!stutter_task) |
634 | return; |
635 | VERBOSE_TOROUT_STRING("Stopping torture_stutter task"); |
636 | kthread_stop(stutter_task); |
637 | stutter_task = NULL; |
638 | } |
639 | |
640 | /* |
641 | * Initialize torture module. Please note that this is -not- invoked via |
642 | * the usual module_init() mechanism, but rather by an explicit call from |
643 | * the client torture module. This call must be paired with a later |
644 | * torture_init_end(). |
645 | * |
646 | * The runnable parameter points to a flag that controls whether or not |
647 | * the test is currently runnable. If there is no such flag, pass in NULL. |
648 | */ |
649 | bool torture_init_begin(char *ttype, bool v, int *runnable) |
650 | { |
651 | mutex_lock(&fullstop_mutex); |
652 | if (torture_type != NULL) { |
653 | pr_alert("torture_init_begin: Refusing %s init: %s running.\n", |
654 | ttype, torture_type); |
655 | pr_alert("torture_init_begin: One torture test at a time!\n"); |
656 | mutex_unlock(&fullstop_mutex); |
657 | return false; |
658 | } |
659 | torture_type = ttype; |
660 | verbose = v; |
661 | torture_runnable = runnable; |
662 | fullstop = FULLSTOP_DONTSTOP; |
663 | return true; |
664 | } |
665 | EXPORT_SYMBOL_GPL(torture_init_begin); |
666 | |
667 | /* |
668 | * Tell the torture module that initialization is complete. |
669 | */ |
670 | void torture_init_end(void) |
671 | { |
672 | mutex_unlock(&fullstop_mutex); |
673 | register_reboot_notifier(&torture_shutdown_nb); |
674 | } |
675 | EXPORT_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 | */ |
692 | bool 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 | } |
709 | EXPORT_SYMBOL_GPL(torture_cleanup_begin); |
710 | |
711 | void torture_cleanup_end(void) |
712 | { |
713 | mutex_lock(&fullstop_mutex); |
714 | torture_type = NULL; |
715 | mutex_unlock(&fullstop_mutex); |
716 | } |
717 | EXPORT_SYMBOL_GPL(torture_cleanup_end); |
718 | |
719 | /* |
720 | * Is it time for the current torture test to stop? |
721 | */ |
722 | bool torture_must_stop(void) |
723 | { |
724 | return torture_must_stop_irq() || kthread_should_stop(); |
725 | } |
726 | EXPORT_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 | */ |
732 | bool torture_must_stop_irq(void) |
733 | { |
734 | return READ_ONCE(fullstop) != FULLSTOP_DONTSTOP; |
735 | } |
736 | EXPORT_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 | */ |
745 | void 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 | } |
756 | EXPORT_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 | */ |
763 | int _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 | } |
778 | EXPORT_SYMBOL_GPL(_torture_create_kthread); |
779 | |
780 | /* |
781 | * Stop a generic kthread, emitting a message. |
782 | */ |
783 | void _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 | } |
791 | EXPORT_SYMBOL_GPL(_torture_stop_kthread); |
792 |