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Paul E. McKenney51b11302014-01-27 11:49:39 -08001/*
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 */
Paul E. McKenney60500032018-05-15 12:25:05 -070023
24#define pr_fmt(fmt) fmt
25
Paul E. McKenney51b11302014-01-27 11:49:39 -080026#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>
Ingo Molnare6017572017-02-01 16:36:40 +010036#include <linux/sched/clock.h>
Paul E. McKenney51b11302014-01-27 11:49:39 -080037#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>
Paul E. McKenney31257c32016-06-18 07:45:43 -070050#include <linux/ktime.h>
Paul E. McKenney51b11302014-01-27 11:49:39 -080051#include <asm/byteorder.h>
52#include <linux/torture.h>
Paul E. McKenneydac95902017-10-04 11:23:10 -070053#include "rcu/rcu.h"
Paul E. McKenney51b11302014-01-27 11:49:39 -080054
55MODULE_LICENSE("GPL");
56MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
57
Paul E. McKenneyb5daa8f2014-01-30 13:38:09 -080058static char *torture_type;
Paul E. McKenney90127d62018-05-09 10:29:18 -070059static int verbose;
Paul E. McKenneyb5daa8f2014-01-30 13:38:09 -080060
Paul E. McKenney36970bb2014-01-30 15:49:29 -080061/* 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. */
65static int fullstop = FULLSTOP_RMMOD;
Paul E. McKenney4622b482014-01-30 15:37:19 -080066static DEFINE_MUTEX(fullstop_mutex);
Paul E. McKenneyf67a3352014-01-29 07:40:27 -080067
Paul E. McKenney2e9e8082014-01-28 15:58:22 -080068#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
75static struct task_struct *onoff_task;
76static long onoff_holdoff;
77static long onoff_interval;
78static long n_offline_attempts;
79static long n_offline_successes;
80static unsigned long sum_offline;
81static int min_offline = -1;
82static int max_offline;
83static long n_online_attempts;
84static long n_online_successes;
85static unsigned long sum_online;
86static int min_online = -1;
87static int max_online;
88
89/*
Paul E. McKenneyd95f5ba2016-04-20 17:18:41 -070090 * 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 */
94bool 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
Paul E. McKenney90127d62018-05-09 10:29:18 -0700104 if (verbose > 1)
Paul E. McKenneyd95f5ba2016-04-20 17:18:41 -0700105 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 {
Paul E. McKenney90127d62018-05-09 10:29:18 -0700117 if (verbose > 1)
Paul E. McKenneyd95f5ba2016-04-20 17:18:41 -0700118 pr_alert("%s" TORTURE_FLAG
119 "torture_onoff task: offlined %d\n",
120 torture_type, cpu);
121 (*n_offl_successes)++;
122 delta = jiffies - starttime;
Paul E. McKenneya2b2df22017-06-22 15:38:26 -0700123 *sum_offl += delta;
Paul E. McKenneyd95f5ba2016-04-20 17:18:41 -0700124 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}
136EXPORT_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 */
143bool 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
Paul E. McKenney90127d62018-05-09 10:29:18 -0700153 if (verbose > 1)
Paul E. McKenneyd95f5ba2016-04-20 17:18:41 -0700154 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 {
Paul E. McKenney90127d62018-05-09 10:29:18 -0700166 if (verbose > 1)
Paul E. McKenneyd95f5ba2016-04-20 17:18:41 -0700167 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}
185EXPORT_SYMBOL_GPL(torture_online);
186
187/*
Paul E. McKenney2e9e8082014-01-28 15:58:22 -0800188 * Execute random CPU-hotplug operations at the interval specified
189 * by the onoff_interval.
190 */
191static int
192torture_onoff(void *arg)
193{
194 int cpu;
Paul E. McKenney2e9e8082014-01-28 15:58:22 -0800195 int maxcpu = -1;
196 DEFINE_TORTURE_RANDOM(rand);
Paul E. McKenney2e9e8082014-01-28 15:58:22 -0800197
198 VERBOSE_TOROUT_STRING("torture_onoff task started");
199 for_each_online_cpu(cpu)
200 maxcpu = cpu;
201 WARN_ON(maxcpu < 0);
Boqun Feng750db0f2016-05-02 10:30:00 +0800202
203 if (maxcpu == 0) {
204 VERBOSE_TOROUT_STRING("Only one CPU, so CPU-hotplug testing is disabled");
205 goto stop;
206 }
207
Paul E. McKenney2e9e8082014-01-28 15:58:22 -0800208 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);
Paul E. McKenneyd95f5ba2016-04-20 17:18:41 -0700215 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);
Paul E. McKenney2e9e8082014-01-28 15:58:22 -0800221 schedule_timeout_interruptible(onoff_interval);
222 }
Boqun Feng750db0f2016-05-02 10:30:00 +0800223
224stop:
Paul E. McKenney7fafaac2014-01-31 17:37:28 -0800225 torture_kthread_stopping("torture_onoff");
Paul E. McKenney2e9e8082014-01-28 15:58:22 -0800226 return 0;
227}
228
229#endif /* #ifdef CONFIG_HOTPLUG_CPU */
230
231/*
232 * Initiate online-offline handling.
233 */
234int torture_onoff_init(long ooholdoff, long oointerval)
235{
Paul E. McKenney47cf29b2014-02-03 11:52:27 -0800236 int ret = 0;
Paul E. McKenney2e9e8082014-01-28 15:58:22 -0800237
Paul E. McKenney47cf29b2014-02-03 11:52:27 -0800238#ifdef CONFIG_HOTPLUG_CPU
Paul E. McKenney2e9e8082014-01-28 15:58:22 -0800239 onoff_holdoff = ooholdoff;
240 onoff_interval = oointerval;
241 if (onoff_interval <= 0)
242 return 0;
Paul E. McKenney47cf29b2014-02-03 11:52:27 -0800243 ret = torture_create_kthread(torture_onoff, NULL, onoff_task);
Paul E. McKenney2e9e8082014-01-28 15:58:22 -0800244#endif /* #ifdef CONFIG_HOTPLUG_CPU */
Paul E. McKenney47cf29b2014-02-03 11:52:27 -0800245 return ret;
Paul E. McKenney2e9e8082014-01-28 15:58:22 -0800246}
247EXPORT_SYMBOL_GPL(torture_onoff_init);
248
249/*
250 * Clean up after online/offline testing.
251 */
Paul E. McKenneycc47ae02014-01-30 14:21:11 -0800252static void torture_onoff_cleanup(void)
Paul E. McKenney2e9e8082014-01-28 15:58:22 -0800253{
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}
262EXPORT_SYMBOL_GPL(torture_onoff_cleanup);
263
264/*
265 * Print online/offline testing statistics.
266 */
Joe Percheseea203f2014-07-14 09:16:15 -0400267void torture_onoff_stats(void)
Paul E. McKenney2e9e8082014-01-28 15:58:22 -0800268{
269#ifdef CONFIG_HOTPLUG_CPU
Joe Percheseea203f2014-07-14 09:16:15 -0400270 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);
Paul E. McKenney2e9e8082014-01-28 15:58:22 -0800276#endif /* #ifdef CONFIG_HOTPLUG_CPU */
Paul E. McKenney2e9e8082014-01-28 15:58:22 -0800277}
278EXPORT_SYMBOL_GPL(torture_onoff_stats);
279
280/*
281 * Were all the online/offline operations successful?
282 */
283bool 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}
292EXPORT_SYMBOL_GPL(torture_onoff_failures);
293
Paul E. McKenney51b11302014-01-27 11:49:39 -0800294#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 */
302unsigned long
303torture_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}
313EXPORT_SYMBOL_GPL(torture_random);
Paul E. McKenneyf67a3352014-01-29 07:40:27 -0800314
315/*
Paul E. McKenney3808dc92014-01-28 15:29:21 -0800316 * Variables for shuffling. The idea is to ensure that each CPU stays
317 * idle for an extended period to test interactions with dyntick idle,
Masahiro Yamadab564d62e2017-02-27 14:29:06 -0800318 * as well as interactions with any per-CPU variables.
Paul E. McKenney3808dc92014-01-28 15:29:21 -0800319 */
320struct shuffle_task {
321 struct list_head st_l;
322 struct task_struct *st_t;
323};
324
325static long shuffle_interval; /* In jiffies. */
326static struct task_struct *shuffler_task;
327static cpumask_var_t shuffle_tmp_mask;
328static int shuffle_idle_cpu; /* Force all torture tasks off this CPU */
329static struct list_head shuffle_task_list = LIST_HEAD_INIT(shuffle_task_list);
330static 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 */
336void 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}
350EXPORT_SYMBOL_GPL(torture_shuffle_task_register);
351
352/*
353 * Unregister all tasks, for example, at the end of the torture run.
354 */
355static 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 */
372static 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;
Iulia Manda5ed63b12014-03-17 15:21:21 +0200389 else
Paul E. McKenney3808dc92014-01-28 15:29:21 -0800390 cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask);
Paul E. McKenney3808dc92014-01-28 15:29:21 -0800391
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 */
404static 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());
Paul E. McKenney7fafaac2014-01-31 17:37:28 -0800412 torture_kthread_stopping("torture_shuffle");
Paul E. McKenney3808dc92014-01-28 15:29:21 -0800413 return 0;
414}
415
416/*
417 * Start the shuffler, with shuffint in jiffies.
418 */
419int torture_shuffle_init(long shuffint)
420{
Paul E. McKenney3808dc92014-01-28 15:29:21 -0800421 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 */
Paul E. McKenney47cf29b2014-02-03 11:52:27 -0800431 return torture_create_kthread(torture_shuffle, NULL, shuffler_task);
Paul E. McKenney3808dc92014-01-28 15:29:21 -0800432}
433EXPORT_SYMBOL_GPL(torture_shuffle_init);
434
435/*
436 * Stop the shuffling.
437 */
Paul E. McKenneycc47ae02014-01-30 14:21:11 -0800438static void torture_shuffle_cleanup(void)
Paul E. McKenney3808dc92014-01-28 15:29:21 -0800439{
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}
448EXPORT_SYMBOL_GPL(torture_shuffle_cleanup);
449
450/*
Paul E. McKenneye991dbc2014-01-31 14:52:13 -0800451 * Variables for auto-shutdown. This allows "lights out" torture runs
452 * to be fully scripted.
453 */
Paul E. McKenneye991dbc2014-01-31 14:52:13 -0800454static struct task_struct *shutdown_task;
Paul E. McKenney31257c32016-06-18 07:45:43 -0700455static ktime_t shutdown_time; /* time to system shutdown. */
Paul E. McKenneye991dbc2014-01-31 14:52:13 -0800456static void (*torture_shutdown_hook)(void);
457
458/*
Paul E. McKenneyf67a3352014-01-29 07:40:27 -0800459 * Absorb kthreads into a kernel function that won't return, so that
460 * they won't ever access module text or data again.
461 */
462void torture_shutdown_absorb(const char *title)
463{
Paul E. McKenney7d0ae802015-03-03 14:57:58 -0800464 while (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
Paul E. McKenney4622b482014-01-30 15:37:19 -0800465 pr_notice("torture thread %s parking due to system shutdown\n",
466 title);
Paul E. McKenneyf67a3352014-01-29 07:40:27 -0800467 schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
468 }
469}
470EXPORT_SYMBOL_GPL(torture_shutdown_absorb);
Paul E. McKenneyb5daa8f2014-01-30 13:38:09 -0800471
472/*
Paul E. McKenneye991dbc2014-01-31 14:52:13 -0800473 * Cause the torture test to shutdown the system after the test has
474 * run for the time specified by the shutdown_secs parameter.
475 */
476static int torture_shutdown(void *arg)
477{
Paul E. McKenney31257c32016-06-18 07:45:43 -0700478 ktime_t ktime_snap;
Paul E. McKenneye991dbc2014-01-31 14:52:13 -0800479
480 VERBOSE_TOROUT_STRING("torture_shutdown task started");
Paul E. McKenney31257c32016-06-18 07:45:43 -0700481 ktime_snap = ktime_get();
482 while (ktime_before(ktime_snap, shutdown_time) &&
Paul E. McKenneye991dbc2014-01-31 14:52:13 -0800483 !torture_must_stop()) {
Paul E. McKenneye991dbc2014-01-31 14:52:13 -0800484 if (verbose)
485 pr_alert("%s" TORTURE_FLAG
Paul E. McKenney31257c32016-06-18 07:45:43 -0700486 "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();
Paul E. McKenneye991dbc2014-01-31 14:52:13 -0800492 }
493 if (torture_must_stop()) {
Paul E. McKenney7fafaac2014-01-31 17:37:28 -0800494 torture_kthread_stopping("torture_shutdown");
Paul E. McKenneye991dbc2014-01-31 14:52:13 -0800495 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. */
Paul E. McKenneyf8818252014-02-07 14:42:51 -0800502 if (torture_shutdown_hook)
503 torture_shutdown_hook();
504 else
505 VERBOSE_TOROUT_STRING("No torture_shutdown_hook(), skipping.");
Paul E. McKenneydac95902017-10-04 11:23:10 -0700506 rcu_ftrace_dump(DUMP_ALL);
Paul E. McKenneye991dbc2014-01-31 14:52:13 -0800507 kernel_power_off(); /* Shut down the system. */
508 return 0;
509}
510
511/*
512 * Start up the shutdown task.
513 */
514int torture_shutdown_init(int ssecs, void (*cleanup)(void))
515{
Paul E. McKenney47cf29b2014-02-03 11:52:27 -0800516 int ret = 0;
Paul E. McKenneye991dbc2014-01-31 14:52:13 -0800517
Paul E. McKenneye991dbc2014-01-31 14:52:13 -0800518 torture_shutdown_hook = cleanup;
Paul E. McKenney31257c32016-06-18 07:45:43 -0700519 if (ssecs > 0) {
520 shutdown_time = ktime_add(ktime_get(), ktime_set(ssecs, 0));
Paul E. McKenney47cf29b2014-02-03 11:52:27 -0800521 ret = torture_create_kthread(torture_shutdown, NULL,
522 shutdown_task);
Paul E. McKenneye991dbc2014-01-31 14:52:13 -0800523 }
Paul E. McKenney47cf29b2014-02-03 11:52:27 -0800524 return ret;
Paul E. McKenneye991dbc2014-01-31 14:52:13 -0800525}
526EXPORT_SYMBOL_GPL(torture_shutdown_init);
527
528/*
Paul E. McKenney4622b482014-01-30 15:37:19 -0800529 * Detect and respond to a system shutdown.
530 */
531static int torture_shutdown_notify(struct notifier_block *unused1,
532 unsigned long unused2, void *unused3)
533{
534 mutex_lock(&fullstop_mutex);
Paul E. McKenney7d0ae802015-03-03 14:57:58 -0800535 if (READ_ONCE(fullstop) == FULLSTOP_DONTSTOP) {
Paul E. McKenneyfac480e2014-01-30 17:06:30 -0800536 VERBOSE_TOROUT_STRING("Unscheduled system shutdown detected");
Paul E. McKenney7d0ae802015-03-03 14:57:58 -0800537 WRITE_ONCE(fullstop, FULLSTOP_SHUTDOWN);
Paul E. McKenneyfac480e2014-01-30 17:06:30 -0800538 } else {
Paul E. McKenney4622b482014-01-30 15:37:19 -0800539 pr_warn("Concurrent rmmod and shutdown illegal!\n");
Paul E. McKenneyfac480e2014-01-30 17:06:30 -0800540 }
Paul E. McKenney4622b482014-01-30 15:37:19 -0800541 mutex_unlock(&fullstop_mutex);
542 return NOTIFY_DONE;
543}
544
545static struct notifier_block torture_shutdown_nb = {
546 .notifier_call = torture_shutdown_notify,
547};
548
549/*
Paul E. McKenneybfefc732014-02-04 12:35:27 -0800550 * 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 */
553static 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/*
Paul E. McKenney628edaa2014-01-31 11:57:43 -0800564 * 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 */
568static struct task_struct *stutter_task;
569static int stutter_pause_test;
570static 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 */
Paul E. McKenney474e59b2018-08-07 14:34:44 -0700576bool stutter_wait(const char *title)
Paul E. McKenney628edaa2014-01-31 11:57:43 -0800577{
Paul E. McKenney4ced3312017-11-21 15:01:02 -0800578 int spt;
579
Paul E. McKenneycee43932018-03-02 16:35:27 -0800580 cond_resched_tasks_rcu_qs();
Paul E. McKenney4ced3312017-11-21 15:01:02 -0800581 spt = READ_ONCE(stutter_pause_test);
Paul E. McKenney29d39392017-11-21 22:07:59 -0800582 for (; spt; spt = READ_ONCE(stutter_pause_test)) {
Paul E. McKenney4ced3312017-11-21 15:01:02 -0800583 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 {
Paul E. McKenney628edaa2014-01-31 11:57:43 -0800589 schedule_timeout_interruptible(round_jiffies_relative(HZ));
Paul E. McKenney4ced3312017-11-21 15:01:02 -0800590 }
Paul E. McKenney628edaa2014-01-31 11:57:43 -0800591 torture_shutdown_absorb(title);
592 }
Paul E. McKenney474e59b2018-08-07 14:34:44 -0700593 return !!spt;
Paul E. McKenney628edaa2014-01-31 11:57:43 -0800594}
595EXPORT_SYMBOL_GPL(stutter_wait);
596
597/*
598 * Cause the torture test to "stutter", starting and stopping all
599 * threads periodically.
600 */
601static int torture_stutter(void *arg)
602{
603 VERBOSE_TOROUT_STRING("torture_stutter task started");
604 do {
Paul E. McKenney4ced3312017-11-21 15:01:02 -0800605 if (!torture_must_stop() && stutter > 1) {
Paul E. McKenney7d0ae802015-03-03 14:57:58 -0800606 WRITE_ONCE(stutter_pause_test, 1);
Paul E. McKenney4ced3312017-11-21 15:01:02 -0800607 schedule_timeout_interruptible(stutter - 1);
608 WRITE_ONCE(stutter_pause_test, 2);
609 schedule_timeout_interruptible(1);
Paul E. McKenney628edaa2014-01-31 11:57:43 -0800610 }
Paul E. McKenney4ced3312017-11-21 15:01:02 -0800611 WRITE_ONCE(stutter_pause_test, 0);
Paul E. McKenney628edaa2014-01-31 11:57:43 -0800612 if (!torture_must_stop())
613 schedule_timeout_interruptible(stutter);
Paul E. McKenney628edaa2014-01-31 11:57:43 -0800614 torture_shutdown_absorb("torture_stutter");
615 } while (!torture_must_stop());
Paul E. McKenney7fafaac2014-01-31 17:37:28 -0800616 torture_kthread_stopping("torture_stutter");
Paul E. McKenney628edaa2014-01-31 11:57:43 -0800617 return 0;
618}
619
620/*
621 * Initialize and kick off the torture_stutter kthread.
622 */
623int torture_stutter_init(int s)
624{
625 int ret;
626
627 stutter = s;
Paul E. McKenney47cf29b2014-02-03 11:52:27 -0800628 ret = torture_create_kthread(torture_stutter, NULL, stutter_task);
629 return ret;
Paul E. McKenney628edaa2014-01-31 11:57:43 -0800630}
631EXPORT_SYMBOL_GPL(torture_stutter_init);
632
633/*
634 * Cleanup after the torture_stutter kthread.
635 */
Paul E. McKenneybfefc732014-02-04 12:35:27 -0800636static void torture_stutter_cleanup(void)
Paul E. McKenney628edaa2014-01-31 11:57:43 -0800637{
638 if (!stutter_task)
639 return;
640 VERBOSE_TOROUT_STRING("Stopping torture_stutter task");
641 kthread_stop(stutter_task);
642 stutter_task = NULL;
643}
Paul E. McKenney628edaa2014-01-31 11:57:43 -0800644
645/*
Paul E. McKenneyb5daa8f2014-01-30 13:38:09 -0800646 * Initialize torture module. Please note that this is -not- invoked via
647 * the usual module_init() mechanism, but rather by an explicit call from
648 * the client torture module. This call must be paired with a later
649 * torture_init_end().
Paul E. McKenney628edaa2014-01-31 11:57:43 -0800650 *
651 * The runnable parameter points to a flag that controls whether or not
652 * the test is currently runnable. If there is no such flag, pass in NULL.
Paul E. McKenneyb5daa8f2014-01-30 13:38:09 -0800653 */
Paul E. McKenney90127d62018-05-09 10:29:18 -0700654bool torture_init_begin(char *ttype, int v)
Paul E. McKenneyb5daa8f2014-01-30 13:38:09 -0800655{
656 mutex_lock(&fullstop_mutex);
Paul E. McKenney52280842014-04-07 09:14:11 -0700657 if (torture_type != NULL) {
Paul E. McKenney9eb51882016-03-21 15:36:40 -0700658 pr_alert("torture_init_begin: Refusing %s init: %s running.\n",
Paul E. McKenney52280842014-04-07 09:14:11 -0700659 ttype, torture_type);
Paul E. McKenney9eb51882016-03-21 15:36:40 -0700660 pr_alert("torture_init_begin: One torture test at a time!\n");
Paul E. McKenney52280842014-04-07 09:14:11 -0700661 mutex_unlock(&fullstop_mutex);
662 return false;
663 }
Paul E. McKenneyb5daa8f2014-01-30 13:38:09 -0800664 torture_type = ttype;
665 verbose = v;
Paul E. McKenney36970bb2014-01-30 15:49:29 -0800666 fullstop = FULLSTOP_DONTSTOP;
Paul E. McKenney52280842014-04-07 09:14:11 -0700667 return true;
Paul E. McKenneyb5daa8f2014-01-30 13:38:09 -0800668}
669EXPORT_SYMBOL_GPL(torture_init_begin);
670
671/*
672 * Tell the torture module that initialization is complete.
673 */
Pranith Kumar2b3f8ff2014-04-16 13:42:09 -0700674void torture_init_end(void)
Paul E. McKenneyb5daa8f2014-01-30 13:38:09 -0800675{
676 mutex_unlock(&fullstop_mutex);
Paul E. McKenney4622b482014-01-30 15:37:19 -0800677 register_reboot_notifier(&torture_shutdown_nb);
Paul E. McKenneyb5daa8f2014-01-30 13:38:09 -0800678}
679EXPORT_SYMBOL_GPL(torture_init_end);
Paul E. McKenneycc47ae02014-01-30 14:21:11 -0800680
681/*
682 * Clean up torture module. Please note that this is -not- invoked via
683 * the usual module_exit() mechanism, but rather by an explicit call from
684 * the client torture module. Returns true if a race with system shutdown
Paul E. McKenneybfefc732014-02-04 12:35:27 -0800685 * is detected, otherwise, all kthreads started by functions in this file
686 * will be shut down.
Paul E. McKenneycc47ae02014-01-30 14:21:11 -0800687 *
688 * This must be called before the caller starts shutting down its own
689 * kthreads.
Davidlohr Buesod36a7a02014-09-11 20:40:21 -0700690 *
691 * Both torture_cleanup_begin() and torture_cleanup_end() must be paired,
692 * in order to correctly perform the cleanup. They are separated because
693 * threads can still need to reference the torture_type type, thus nullify
694 * only after completing all other relevant calls.
Paul E. McKenneycc47ae02014-01-30 14:21:11 -0800695 */
Davidlohr Buesod36a7a02014-09-11 20:40:21 -0700696bool torture_cleanup_begin(void)
Paul E. McKenneycc47ae02014-01-30 14:21:11 -0800697{
698 mutex_lock(&fullstop_mutex);
Paul E. McKenney7d0ae802015-03-03 14:57:58 -0800699 if (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
Paul E. McKenneycc47ae02014-01-30 14:21:11 -0800700 pr_warn("Concurrent rmmod and shutdown illegal!\n");
701 mutex_unlock(&fullstop_mutex);
702 schedule_timeout_uninterruptible(10);
703 return true;
704 }
Paul E. McKenney7d0ae802015-03-03 14:57:58 -0800705 WRITE_ONCE(fullstop, FULLSTOP_RMMOD);
Paul E. McKenneycc47ae02014-01-30 14:21:11 -0800706 mutex_unlock(&fullstop_mutex);
Paul E. McKenneybfefc732014-02-04 12:35:27 -0800707 torture_shutdown_cleanup();
Paul E. McKenneycc47ae02014-01-30 14:21:11 -0800708 torture_shuffle_cleanup();
Paul E. McKenneybfefc732014-02-04 12:35:27 -0800709 torture_stutter_cleanup();
Paul E. McKenneycc47ae02014-01-30 14:21:11 -0800710 torture_onoff_cleanup();
Davidlohr Buesod36a7a02014-09-11 20:40:21 -0700711 return false;
712}
713EXPORT_SYMBOL_GPL(torture_cleanup_begin);
714
715void torture_cleanup_end(void)
716{
Paul E. McKenney52280842014-04-07 09:14:11 -0700717 mutex_lock(&fullstop_mutex);
718 torture_type = NULL;
719 mutex_unlock(&fullstop_mutex);
Paul E. McKenneycc47ae02014-01-30 14:21:11 -0800720}
Davidlohr Buesod36a7a02014-09-11 20:40:21 -0700721EXPORT_SYMBOL_GPL(torture_cleanup_end);
Paul E. McKenney36970bb2014-01-30 15:49:29 -0800722
723/*
724 * Is it time for the current torture test to stop?
725 */
726bool torture_must_stop(void)
727{
728 return torture_must_stop_irq() || kthread_should_stop();
729}
730EXPORT_SYMBOL_GPL(torture_must_stop);
731
732/*
733 * Is it time for the current torture test to stop? This is the irq-safe
734 * version, hence no check for kthread_should_stop().
735 */
736bool torture_must_stop_irq(void)
737{
Paul E. McKenney7d0ae802015-03-03 14:57:58 -0800738 return READ_ONCE(fullstop) != FULLSTOP_DONTSTOP;
Paul E. McKenney36970bb2014-01-30 15:49:29 -0800739}
740EXPORT_SYMBOL_GPL(torture_must_stop_irq);
Paul E. McKenney7fafaac2014-01-31 17:37:28 -0800741
742/*
743 * Each kthread must wait for kthread_should_stop() before returning from
744 * its top-level function, otherwise segfaults ensue. This function
745 * prints a "stopping" message and waits for kthread_should_stop(), and
746 * should be called from all torture kthreads immediately prior to
747 * returning.
748 */
749void torture_kthread_stopping(char *title)
750{
Paul E. McKenney0d6821d2014-03-03 16:58:03 -0800751 char buf[128];
752
753 snprintf(buf, sizeof(buf), "Stopping %s", title);
754 VERBOSE_TOROUT_STRING(buf);
Paul E. McKenney7fafaac2014-01-31 17:37:28 -0800755 while (!kthread_should_stop()) {
756 torture_shutdown_absorb(title);
757 schedule_timeout_uninterruptible(1);
758 }
759}
760EXPORT_SYMBOL_GPL(torture_kthread_stopping);
Paul E. McKenney47cf29b2014-02-03 11:52:27 -0800761
762/*
763 * Create a generic torture kthread that is immediately runnable. If you
764 * need the kthread to be stopped so that you can do something to it before
765 * it starts, you will need to open-code your own.
766 */
767int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
768 char *f, struct task_struct **tp)
769{
770 int ret = 0;
771
772 VERBOSE_TOROUT_STRING(m);
Kees Cook69459152014-05-22 11:51:04 -0700773 *tp = kthread_run(fn, arg, "%s", s);
Paul E. McKenney47cf29b2014-02-03 11:52:27 -0800774 if (IS_ERR(*tp)) {
775 ret = PTR_ERR(*tp);
776 VERBOSE_TOROUT_ERRSTRING(f);
777 *tp = NULL;
778 }
779 torture_shuffle_task_register(*tp);
780 return ret;
781}
782EXPORT_SYMBOL_GPL(_torture_create_kthread);
Paul E. McKenney9c029b82014-02-04 11:47:08 -0800783
784/*
785 * Stop a generic kthread, emitting a message.
786 */
787void _torture_stop_kthread(char *m, struct task_struct **tp)
788{
789 if (*tp == NULL)
790 return;
791 VERBOSE_TOROUT_STRING(m);
792 kthread_stop(*tp);
793 *tp = NULL;
794}
795EXPORT_SYMBOL_GPL(_torture_stop_kthread);