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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 | */ | |
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 | */ | |
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 | |
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 | */ | |
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 | */ | |
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 | EXPORT_SYMBOL_GPL(torture_onoff_cleanup); | |
267 | ||
268 | /* | |
269 | * Print online/offline testing statistics. | |
270 | */ | |
271 | void torture_onoff_stats(void) | |
272 | { | |
273 | #ifdef CONFIG_HOTPLUG_CPU | |
274 | pr_cont("onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ", | |
275 | n_online_successes, n_online_attempts, | |
276 | n_offline_successes, n_offline_attempts, | |
277 | min_online, max_online, | |
278 | min_offline, max_offline, | |
279 | sum_online, sum_offline, HZ); | |
280 | #endif /* #ifdef CONFIG_HOTPLUG_CPU */ | |
281 | } | |
282 | EXPORT_SYMBOL_GPL(torture_onoff_stats); | |
283 | ||
284 | /* | |
285 | * Were all the online/offline operations successful? | |
286 | */ | |
287 | bool torture_onoff_failures(void) | |
288 | { | |
289 | #ifdef CONFIG_HOTPLUG_CPU | |
290 | return n_online_successes != n_online_attempts || | |
291 | n_offline_successes != n_offline_attempts; | |
292 | #else /* #ifdef CONFIG_HOTPLUG_CPU */ | |
293 | return false; | |
294 | #endif /* #else #ifdef CONFIG_HOTPLUG_CPU */ | |
295 | } | |
296 | EXPORT_SYMBOL_GPL(torture_onoff_failures); | |
297 | ||
298 | #define TORTURE_RANDOM_MULT 39916801 /* prime */ | |
299 | #define TORTURE_RANDOM_ADD 479001701 /* prime */ | |
300 | #define TORTURE_RANDOM_REFRESH 10000 | |
301 | ||
302 | /* | |
303 | * Crude but fast random-number generator. Uses a linear congruential | |
304 | * generator, with occasional help from cpu_clock(). | |
305 | */ | |
306 | unsigned long | |
307 | torture_random(struct torture_random_state *trsp) | |
308 | { | |
309 | if (--trsp->trs_count < 0) { | |
310 | trsp->trs_state += (unsigned long)local_clock(); | |
311 | trsp->trs_count = TORTURE_RANDOM_REFRESH; | |
312 | } | |
313 | trsp->trs_state = trsp->trs_state * TORTURE_RANDOM_MULT + | |
314 | TORTURE_RANDOM_ADD; | |
315 | return swahw32(trsp->trs_state); | |
316 | } | |
317 | EXPORT_SYMBOL_GPL(torture_random); | |
318 | ||
319 | /* | |
320 | * Variables for shuffling. The idea is to ensure that each CPU stays | |
321 | * idle for an extended period to test interactions with dyntick idle, | |
322 | * as well as interactions with any per-CPU variables. | |
323 | */ | |
324 | struct shuffle_task { | |
325 | struct list_head st_l; | |
326 | struct task_struct *st_t; | |
327 | }; | |
328 | ||
329 | static long shuffle_interval; /* In jiffies. */ | |
330 | static struct task_struct *shuffler_task; | |
331 | static cpumask_var_t shuffle_tmp_mask; | |
332 | static int shuffle_idle_cpu; /* Force all torture tasks off this CPU */ | |
333 | static struct list_head shuffle_task_list = LIST_HEAD_INIT(shuffle_task_list); | |
334 | static DEFINE_MUTEX(shuffle_task_mutex); | |
335 | ||
336 | /* | |
337 | * Register a task to be shuffled. If there is no memory, just splat | |
338 | * and don't bother registering. | |
339 | */ | |
340 | void torture_shuffle_task_register(struct task_struct *tp) | |
341 | { | |
342 | struct shuffle_task *stp; | |
343 | ||
344 | if (WARN_ON_ONCE(tp == NULL)) | |
345 | return; | |
346 | stp = kmalloc(sizeof(*stp), GFP_KERNEL); | |
347 | if (WARN_ON_ONCE(stp == NULL)) | |
348 | return; | |
349 | stp->st_t = tp; | |
350 | mutex_lock(&shuffle_task_mutex); | |
351 | list_add(&stp->st_l, &shuffle_task_list); | |
352 | mutex_unlock(&shuffle_task_mutex); | |
353 | } | |
354 | EXPORT_SYMBOL_GPL(torture_shuffle_task_register); | |
355 | ||
356 | /* | |
357 | * Unregister all tasks, for example, at the end of the torture run. | |
358 | */ | |
359 | static void torture_shuffle_task_unregister_all(void) | |
360 | { | |
361 | struct shuffle_task *stp; | |
362 | struct shuffle_task *p; | |
363 | ||
364 | mutex_lock(&shuffle_task_mutex); | |
365 | list_for_each_entry_safe(stp, p, &shuffle_task_list, st_l) { | |
366 | list_del(&stp->st_l); | |
367 | kfree(stp); | |
368 | } | |
369 | mutex_unlock(&shuffle_task_mutex); | |
370 | } | |
371 | ||
372 | /* Shuffle tasks such that we allow shuffle_idle_cpu to become idle. | |
373 | * A special case is when shuffle_idle_cpu = -1, in which case we allow | |
374 | * the tasks to run on all CPUs. | |
375 | */ | |
376 | static void torture_shuffle_tasks(void) | |
377 | { | |
378 | struct shuffle_task *stp; | |
379 | ||
380 | cpumask_setall(shuffle_tmp_mask); | |
381 | get_online_cpus(); | |
382 | ||
383 | /* No point in shuffling if there is only one online CPU (ex: UP) */ | |
384 | if (num_online_cpus() == 1) { | |
385 | put_online_cpus(); | |
386 | return; | |
387 | } | |
388 | ||
389 | /* Advance to the next CPU. Upon overflow, don't idle any CPUs. */ | |
390 | shuffle_idle_cpu = cpumask_next(shuffle_idle_cpu, shuffle_tmp_mask); | |
391 | if (shuffle_idle_cpu >= nr_cpu_ids) | |
392 | shuffle_idle_cpu = -1; | |
393 | else | |
394 | cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask); | |
395 | ||
396 | mutex_lock(&shuffle_task_mutex); | |
397 | list_for_each_entry(stp, &shuffle_task_list, st_l) | |
398 | set_cpus_allowed_ptr(stp->st_t, shuffle_tmp_mask); | |
399 | mutex_unlock(&shuffle_task_mutex); | |
400 | ||
401 | put_online_cpus(); | |
402 | } | |
403 | ||
404 | /* Shuffle tasks across CPUs, with the intent of allowing each CPU in the | |
405 | * system to become idle at a time and cut off its timer ticks. This is meant | |
406 | * to test the support for such tickless idle CPU in RCU. | |
407 | */ | |
408 | static int torture_shuffle(void *arg) | |
409 | { | |
410 | VERBOSE_TOROUT_STRING("torture_shuffle task started"); | |
411 | do { | |
412 | schedule_timeout_interruptible(shuffle_interval); | |
413 | torture_shuffle_tasks(); | |
414 | torture_shutdown_absorb("torture_shuffle"); | |
415 | } while (!torture_must_stop()); | |
416 | torture_kthread_stopping("torture_shuffle"); | |
417 | return 0; | |
418 | } | |
419 | ||
420 | /* | |
421 | * Start the shuffler, with shuffint in jiffies. | |
422 | */ | |
423 | int torture_shuffle_init(long shuffint) | |
424 | { | |
425 | shuffle_interval = shuffint; | |
426 | ||
427 | shuffle_idle_cpu = -1; | |
428 | ||
429 | if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) { | |
430 | VERBOSE_TOROUT_ERRSTRING("Failed to alloc mask"); | |
431 | return -ENOMEM; | |
432 | } | |
433 | ||
434 | /* Create the shuffler thread */ | |
435 | return torture_create_kthread(torture_shuffle, NULL, shuffler_task); | |
436 | } | |
437 | EXPORT_SYMBOL_GPL(torture_shuffle_init); | |
438 | ||
439 | /* | |
440 | * Stop the shuffling. | |
441 | */ | |
442 | static void torture_shuffle_cleanup(void) | |
443 | { | |
444 | torture_shuffle_task_unregister_all(); | |
445 | if (shuffler_task) { | |
446 | VERBOSE_TOROUT_STRING("Stopping torture_shuffle task"); | |
447 | kthread_stop(shuffler_task); | |
448 | free_cpumask_var(shuffle_tmp_mask); | |
449 | } | |
450 | shuffler_task = NULL; | |
451 | } | |
452 | EXPORT_SYMBOL_GPL(torture_shuffle_cleanup); | |
453 | ||
454 | /* | |
455 | * Variables for auto-shutdown. This allows "lights out" torture runs | |
456 | * to be fully scripted. | |
457 | */ | |
458 | static struct task_struct *shutdown_task; | |
459 | static ktime_t shutdown_time; /* time to system shutdown. */ | |
460 | static void (*torture_shutdown_hook)(void); | |
461 | ||
462 | /* | |
463 | * Absorb kthreads into a kernel function that won't return, so that | |
464 | * they won't ever access module text or data again. | |
465 | */ | |
466 | void torture_shutdown_absorb(const char *title) | |
467 | { | |
468 | while (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) { | |
469 | pr_notice("torture thread %s parking due to system shutdown\n", | |
470 | title); | |
471 | schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT); | |
472 | } | |
473 | } | |
474 | EXPORT_SYMBOL_GPL(torture_shutdown_absorb); | |
475 | ||
476 | /* | |
477 | * Cause the torture test to shutdown the system after the test has | |
478 | * run for the time specified by the shutdown_secs parameter. | |
479 | */ | |
480 | static int torture_shutdown(void *arg) | |
481 | { | |
482 | ktime_t ktime_snap; | |
483 | ||
484 | VERBOSE_TOROUT_STRING("torture_shutdown task started"); | |
485 | ktime_snap = ktime_get(); | |
486 | while (ktime_before(ktime_snap, shutdown_time) && | |
487 | !torture_must_stop()) { | |
488 | if (verbose) | |
489 | pr_alert("%s" TORTURE_FLAG | |
490 | "torture_shutdown task: %llu ms remaining\n", | |
491 | torture_type, | |
492 | ktime_ms_delta(shutdown_time, ktime_snap)); | |
493 | set_current_state(TASK_INTERRUPTIBLE); | |
494 | schedule_hrtimeout(&shutdown_time, HRTIMER_MODE_ABS); | |
495 | ktime_snap = ktime_get(); | |
496 | } | |
497 | if (torture_must_stop()) { | |
498 | torture_kthread_stopping("torture_shutdown"); | |
499 | return 0; | |
500 | } | |
501 | ||
502 | /* OK, shut down the system. */ | |
503 | ||
504 | VERBOSE_TOROUT_STRING("torture_shutdown task shutting down system"); | |
505 | shutdown_task = NULL; /* Avoid self-kill deadlock. */ | |
506 | if (torture_shutdown_hook) | |
507 | torture_shutdown_hook(); | |
508 | else | |
509 | VERBOSE_TOROUT_STRING("No torture_shutdown_hook(), skipping."); | |
510 | rcu_ftrace_dump(DUMP_ALL); | |
511 | kernel_power_off(); /* Shut down the system. */ | |
512 | return 0; | |
513 | } | |
514 | ||
515 | /* | |
516 | * Start up the shutdown task. | |
517 | */ | |
518 | int torture_shutdown_init(int ssecs, void (*cleanup)(void)) | |
519 | { | |
520 | torture_shutdown_hook = cleanup; | |
521 | if (ssecs > 0) { | |
522 | shutdown_time = ktime_add(ktime_get(), ktime_set(ssecs, 0)); | |
523 | return torture_create_kthread(torture_shutdown, NULL, | |
524 | shutdown_task); | |
525 | } | |
526 | return 0; | |
527 | } | |
528 | EXPORT_SYMBOL_GPL(torture_shutdown_init); | |
529 | ||
530 | /* | |
531 | * Detect and respond to a system shutdown. | |
532 | */ | |
533 | static int torture_shutdown_notify(struct notifier_block *unused1, | |
534 | unsigned long unused2, void *unused3) | |
535 | { | |
536 | mutex_lock(&fullstop_mutex); | |
537 | if (READ_ONCE(fullstop) == FULLSTOP_DONTSTOP) { | |
538 | VERBOSE_TOROUT_STRING("Unscheduled system shutdown detected"); | |
539 | WRITE_ONCE(fullstop, FULLSTOP_SHUTDOWN); | |
540 | } else { | |
541 | pr_warn("Concurrent rmmod and shutdown illegal!\n"); | |
542 | } | |
543 | mutex_unlock(&fullstop_mutex); | |
544 | return NOTIFY_DONE; | |
545 | } | |
546 | ||
547 | static struct notifier_block torture_shutdown_nb = { | |
548 | .notifier_call = torture_shutdown_notify, | |
549 | }; | |
550 | ||
551 | /* | |
552 | * Shut down the shutdown task. Say what??? Heh! This can happen if | |
553 | * the torture module gets an rmmod before the shutdown time arrives. ;-) | |
554 | */ | |
555 | static void torture_shutdown_cleanup(void) | |
556 | { | |
557 | unregister_reboot_notifier(&torture_shutdown_nb); | |
558 | if (shutdown_task != NULL) { | |
559 | VERBOSE_TOROUT_STRING("Stopping torture_shutdown task"); | |
560 | kthread_stop(shutdown_task); | |
561 | } | |
562 | shutdown_task = NULL; | |
563 | } | |
564 | ||
565 | /* | |
566 | * Variables for stuttering, which means to periodically pause and | |
567 | * restart testing in order to catch bugs that appear when load is | |
568 | * suddenly applied to or removed from the system. | |
569 | */ | |
570 | static struct task_struct *stutter_task; | |
571 | static int stutter_pause_test; | |
572 | static int stutter; | |
573 | ||
574 | /* | |
575 | * Block until the stutter interval ends. This must be called periodically | |
576 | * by all running kthreads that need to be subject to stuttering. | |
577 | */ | |
578 | bool stutter_wait(const char *title) | |
579 | { | |
580 | int spt; | |
581 | ||
582 | cond_resched_tasks_rcu_qs(); | |
583 | spt = READ_ONCE(stutter_pause_test); | |
584 | for (; spt; spt = READ_ONCE(stutter_pause_test)) { | |
585 | if (spt == 1) { | |
586 | schedule_timeout_interruptible(1); | |
587 | } else if (spt == 2) { | |
588 | while (READ_ONCE(stutter_pause_test)) | |
589 | cond_resched(); | |
590 | } else { | |
591 | schedule_timeout_interruptible(round_jiffies_relative(HZ)); | |
592 | } | |
593 | torture_shutdown_absorb(title); | |
594 | } | |
595 | return !!spt; | |
596 | } | |
597 | EXPORT_SYMBOL_GPL(stutter_wait); | |
598 | ||
599 | /* | |
600 | * Cause the torture test to "stutter", starting and stopping all | |
601 | * threads periodically. | |
602 | */ | |
603 | static int torture_stutter(void *arg) | |
604 | { | |
605 | VERBOSE_TOROUT_STRING("torture_stutter task started"); | |
606 | do { | |
607 | if (!torture_must_stop() && stutter > 1) { | |
608 | WRITE_ONCE(stutter_pause_test, 1); | |
609 | schedule_timeout_interruptible(stutter - 1); | |
610 | WRITE_ONCE(stutter_pause_test, 2); | |
611 | schedule_timeout_interruptible(1); | |
612 | } | |
613 | WRITE_ONCE(stutter_pause_test, 0); | |
614 | if (!torture_must_stop()) | |
615 | schedule_timeout_interruptible(stutter); | |
616 | torture_shutdown_absorb("torture_stutter"); | |
617 | } while (!torture_must_stop()); | |
618 | torture_kthread_stopping("torture_stutter"); | |
619 | return 0; | |
620 | } | |
621 | ||
622 | /* | |
623 | * Initialize and kick off the torture_stutter kthread. | |
624 | */ | |
625 | int torture_stutter_init(const int s) | |
626 | { | |
627 | stutter = s; | |
628 | return torture_create_kthread(torture_stutter, NULL, stutter_task); | |
629 | } | |
630 | EXPORT_SYMBOL_GPL(torture_stutter_init); | |
631 | ||
632 | /* | |
633 | * Cleanup after the torture_stutter kthread. | |
634 | */ | |
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 | */ | |
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 | */ | |
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 | */ | |
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 | ||
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 | */ | |
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 | */ | |
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 | */ | |
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 | */ | |
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 | */ | |
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); |