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Linux 4.15.6
[linux/fpc-iii.git] / kernel / rcu / rcutorture.c
blob74f6b0146b9878f3b9d42dd85b6bd1924be08387
1 /*
2 * Read-Copy Update module-based torture test facility
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, 2005, 2006
19 *
20 * Authors: Paul E. McKenney <paulmck@us.ibm.com>
21 * Josh Triplett <josh@joshtriplett.org>
22 *
23 * See also: Documentation/RCU/torture.txt
24 */
25 #include <linux/types.h>
26 #include <linux/kernel.h>
27 #include <linux/init.h>
28 #include <linux/module.h>
29 #include <linux/kthread.h>
30 #include <linux/err.h>
31 #include <linux/spinlock.h>
32 #include <linux/smp.h>
33 #include <linux/rcupdate.h>
34 #include <linux/interrupt.h>
35 #include <linux/sched/signal.h>
36 #include <uapi/linux/sched/types.h>
37 #include <linux/atomic.h>
38 #include <linux/bitops.h>
39 #include <linux/completion.h>
40 #include <linux/moduleparam.h>
41 #include <linux/percpu.h>
42 #include <linux/notifier.h>
43 #include <linux/reboot.h>
44 #include <linux/freezer.h>
45 #include <linux/cpu.h>
46 #include <linux/delay.h>
47 #include <linux/stat.h>
48 #include <linux/srcu.h>
49 #include <linux/slab.h>
50 #include <linux/trace_clock.h>
51 #include <asm/byteorder.h>
52 #include <linux/torture.h>
53 #include <linux/vmalloc.h>
54 #include <linux/sched/debug.h>
55
56 #include "rcu.h"
57
58 MODULE_LICENSE("GPL");
59 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
60
61
62 torture_param(int, cbflood_inter_holdoff, HZ,
63 "Holdoff between floods (jiffies)");
64 torture_param(int, cbflood_intra_holdoff, 1,
65 "Holdoff between bursts (jiffies)");
66 torture_param(int, cbflood_n_burst, 3, "# bursts in flood, zero to disable");
67 torture_param(int, cbflood_n_per_burst, 20000,
68 "# callbacks per burst in flood");
69 torture_param(int, fqs_duration, 0,
70 "Duration of fqs bursts (us), 0 to disable");
71 torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
72 torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
73 torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
74 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
75 torture_param(bool, gp_normal, false,
76 "Use normal (non-expedited) GP wait primitives");
77 torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
78 torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
79 torture_param(int, n_barrier_cbs, 0,
80 "# of callbacks/kthreads for barrier testing");
81 torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
82 torture_param(int, nreaders, -1, "Number of RCU reader threads");
83 torture_param(int, object_debug, 0,
84 "Enable debug-object double call_rcu() testing");
85 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
86 torture_param(int, onoff_interval, 0,
87 "Time between CPU hotplugs (s), 0=disable");
88 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
89 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
90 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
91 torture_param(int, stall_cpu_holdoff, 10,
92 "Time to wait before starting stall (s).");
93 torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling.");
94 torture_param(int, stat_interval, 60,
95 "Number of seconds between stats printk()s");
96 torture_param(int, stutter, 5, "Number of seconds to run/halt test");
97 torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
98 torture_param(int, test_boost_duration, 4,
99 "Duration of each boost test, seconds.");
100 torture_param(int, test_boost_interval, 7,
101 "Interval between boost tests, seconds.");
102 torture_param(bool, test_no_idle_hz, true,
103 "Test support for tickless idle CPUs");
104 torture_param(bool, verbose, true,
105 "Enable verbose debugging printk()s");
106
107 static char *torture_type = "rcu";
108 module_param(torture_type, charp, 0444);
109 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, ...)");
110
111 static int nrealreaders;
112 static int ncbflooders;
113 static struct task_struct *writer_task;
114 static struct task_struct **fakewriter_tasks;
115 static struct task_struct **reader_tasks;
116 static struct task_struct *stats_task;
117 static struct task_struct **cbflood_task;
118 static struct task_struct *fqs_task;
119 static struct task_struct *boost_tasks[NR_CPUS];
120 static struct task_struct *stall_task;
121 static struct task_struct **barrier_cbs_tasks;
122 static struct task_struct *barrier_task;
123
124 #define RCU_TORTURE_PIPE_LEN 10
125
126 struct rcu_torture {
127 struct rcu_head rtort_rcu;
128 int rtort_pipe_count;
129 struct list_head rtort_free;
130 int rtort_mbtest;
131 };
132
133 static LIST_HEAD(rcu_torture_freelist);
134 static struct rcu_torture __rcu *rcu_torture_current;
135 static unsigned long rcu_torture_current_version;
136 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
137 static DEFINE_SPINLOCK(rcu_torture_lock);
138 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count);
139 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch);
140 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
141 static atomic_t n_rcu_torture_alloc;
142 static atomic_t n_rcu_torture_alloc_fail;
143 static atomic_t n_rcu_torture_free;
144 static atomic_t n_rcu_torture_mberror;
145 static atomic_t n_rcu_torture_error;
146 static long n_rcu_torture_barrier_error;
147 static long n_rcu_torture_boost_ktrerror;
148 static long n_rcu_torture_boost_rterror;
149 static long n_rcu_torture_boost_failure;
150 static long n_rcu_torture_boosts;
151 static long n_rcu_torture_timers;
152 static long n_barrier_attempts;
153 static long n_barrier_successes;
154 static atomic_long_t n_cbfloods;
155 static struct list_head rcu_torture_removed;
156
157 static int rcu_torture_writer_state;
158 #define RTWS_FIXED_DELAY 0
159 #define RTWS_DELAY 1
160 #define RTWS_REPLACE 2
161 #define RTWS_DEF_FREE 3
162 #define RTWS_EXP_SYNC 4
163 #define RTWS_COND_GET 5
164 #define RTWS_COND_SYNC 6
165 #define RTWS_SYNC 7
166 #define RTWS_STUTTER 8
167 #define RTWS_STOPPING 9
168 static const char * const rcu_torture_writer_state_names[] = {
169 "RTWS_FIXED_DELAY",
170 "RTWS_DELAY",
171 "RTWS_REPLACE",
172 "RTWS_DEF_FREE",
173 "RTWS_EXP_SYNC",
174 "RTWS_COND_GET",
175 "RTWS_COND_SYNC",
176 "RTWS_SYNC",
177 "RTWS_STUTTER",
178 "RTWS_STOPPING",
179 };
180
181 static const char *rcu_torture_writer_state_getname(void)
182 {
183 unsigned int i = READ_ONCE(rcu_torture_writer_state);
184
185 if (i >= ARRAY_SIZE(rcu_torture_writer_state_names))
186 return "???";
187 return rcu_torture_writer_state_names[i];
188 }
189
190 static int torture_runnable = IS_ENABLED(MODULE);
191 module_param(torture_runnable, int, 0444);
192 MODULE_PARM_DESC(torture_runnable, "Start rcutorture at boot");
193
194 #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
195 #define rcu_can_boost() 1
196 #else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
197 #define rcu_can_boost() 0
198 #endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
199
200 #ifdef CONFIG_RCU_TRACE
201 static u64 notrace rcu_trace_clock_local(void)
202 {
203 u64 ts = trace_clock_local();
204
205 (void)do_div(ts, NSEC_PER_USEC);
206 return ts;
207 }
208 #else /* #ifdef CONFIG_RCU_TRACE */
209 static u64 notrace rcu_trace_clock_local(void)
210 {
211 return 0ULL;
212 }
213 #endif /* #else #ifdef CONFIG_RCU_TRACE */
214
215 static unsigned long boost_starttime; /* jiffies of next boost test start. */
216 static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
217 /* and boost task create/destroy. */
218 static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
219 static bool barrier_phase; /* Test phase. */
220 static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
221 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
222 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
223
224 /*
225 * Allocate an element from the rcu_tortures pool.
226 */
227 static struct rcu_torture *
228 rcu_torture_alloc(void)
229 {
230 struct list_head *p;
231
232 spin_lock_bh(&rcu_torture_lock);
233 if (list_empty(&rcu_torture_freelist)) {
234 atomic_inc(&n_rcu_torture_alloc_fail);
235 spin_unlock_bh(&rcu_torture_lock);
236 return NULL;
237 }
238 atomic_inc(&n_rcu_torture_alloc);
239 p = rcu_torture_freelist.next;
240 list_del_init(p);
241 spin_unlock_bh(&rcu_torture_lock);
242 return container_of(p, struct rcu_torture, rtort_free);
243 }
244
245 /*
246 * Free an element to the rcu_tortures pool.
247 */
248 static void
249 rcu_torture_free(struct rcu_torture *p)
250 {
251 atomic_inc(&n_rcu_torture_free);
252 spin_lock_bh(&rcu_torture_lock);
253 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
254 spin_unlock_bh(&rcu_torture_lock);
255 }
256
257 /*
258 * Operations vector for selecting different types of tests.
259 */
260
261 struct rcu_torture_ops {
262 int ttype;
263 void (*init)(void);
264 void (*cleanup)(void);
265 int (*readlock)(void);
266 void (*read_delay)(struct torture_random_state *rrsp);
267 void (*readunlock)(int idx);
268 unsigned long (*started)(void);
269 unsigned long (*completed)(void);
270 void (*deferred_free)(struct rcu_torture *p);
271 void (*sync)(void);
272 void (*exp_sync)(void);
273 unsigned long (*get_state)(void);
274 void (*cond_sync)(unsigned long oldstate);
275 call_rcu_func_t call;
276 void (*cb_barrier)(void);
277 void (*fqs)(void);
278 void (*stats)(void);
279 int irq_capable;
280 int can_boost;
281 const char *name;
282 };
283
284 static struct rcu_torture_ops *cur_ops;
285
286 /*
287 * Definitions for rcu torture testing.
288 */
289
290 static int rcu_torture_read_lock(void) __acquires(RCU)
291 {
292 rcu_read_lock();
293 return 0;
294 }
295
296 static void rcu_read_delay(struct torture_random_state *rrsp)
297 {
298 unsigned long started;
299 unsigned long completed;
300 const unsigned long shortdelay_us = 200;
301 const unsigned long longdelay_ms = 50;
302 unsigned long long ts;
303
304 /* We want a short delay sometimes to make a reader delay the grace
305 * period, and we want a long delay occasionally to trigger
306 * force_quiescent_state. */
307
308 if (!(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) {
309 started = cur_ops->completed();
310 ts = rcu_trace_clock_local();
311 mdelay(longdelay_ms);
312 completed = cur_ops->completed();
313 do_trace_rcu_torture_read(cur_ops->name, NULL, ts,
314 started, completed);
315 }
316 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
317 udelay(shortdelay_us);
318 #ifdef CONFIG_PREEMPT
319 if (!preempt_count() &&
320 !(torture_random(rrsp) % (nrealreaders * 20000)))
321 preempt_schedule(); /* No QS if preempt_disable() in effect */
322 #endif
323 }
324
325 static void rcu_torture_read_unlock(int idx) __releases(RCU)
326 {
327 rcu_read_unlock();
328 }
329
330 /*
331 * Update callback in the pipe. This should be invoked after a grace period.
332 */
333 static bool
334 rcu_torture_pipe_update_one(struct rcu_torture *rp)
335 {
336 int i;
337
338 i = rp->rtort_pipe_count;
339 if (i > RCU_TORTURE_PIPE_LEN)
340 i = RCU_TORTURE_PIPE_LEN;
341 atomic_inc(&rcu_torture_wcount[i]);
342 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
343 rp->rtort_mbtest = 0;
344 return true;
345 }
346 return false;
347 }
348
349 /*
350 * Update all callbacks in the pipe. Suitable for synchronous grace-period
351 * primitives.
352 */
353 static void
354 rcu_torture_pipe_update(struct rcu_torture *old_rp)
355 {
356 struct rcu_torture *rp;
357 struct rcu_torture *rp1;
358
359 if (old_rp)
360 list_add(&old_rp->rtort_free, &rcu_torture_removed);
361 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
362 if (rcu_torture_pipe_update_one(rp)) {
363 list_del(&rp->rtort_free);
364 rcu_torture_free(rp);
365 }
366 }
367 }
368
369 static void
370 rcu_torture_cb(struct rcu_head *p)
371 {
372 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
373
374 if (torture_must_stop_irq()) {
375 /* Test is ending, just drop callbacks on the floor. */
376 /* The next initialization will pick up the pieces. */
377 return;
378 }
379 if (rcu_torture_pipe_update_one(rp))
380 rcu_torture_free(rp);
381 else
382 cur_ops->deferred_free(rp);
383 }
384
385 static unsigned long rcu_no_completed(void)
386 {
387 return 0;
388 }
389
390 static void rcu_torture_deferred_free(struct rcu_torture *p)
391 {
392 call_rcu(&p->rtort_rcu, rcu_torture_cb);
393 }
394
395 static void rcu_sync_torture_init(void)
396 {
397 INIT_LIST_HEAD(&rcu_torture_removed);
398 }
399
400 static struct rcu_torture_ops rcu_ops = {
401 .ttype = RCU_FLAVOR,
402 .init = rcu_sync_torture_init,
403 .readlock = rcu_torture_read_lock,
404 .read_delay = rcu_read_delay,
405 .readunlock = rcu_torture_read_unlock,
406 .started = rcu_batches_started,
407 .completed = rcu_batches_completed,
408 .deferred_free = rcu_torture_deferred_free,
409 .sync = synchronize_rcu,
410 .exp_sync = synchronize_rcu_expedited,
411 .get_state = get_state_synchronize_rcu,
412 .cond_sync = cond_synchronize_rcu,
413 .call = call_rcu,
414 .cb_barrier = rcu_barrier,
415 .fqs = rcu_force_quiescent_state,
416 .stats = NULL,
417 .irq_capable = 1,
418 .can_boost = rcu_can_boost(),
419 .name = "rcu"
420 };
421
422 /*
423 * Definitions for rcu_bh torture testing.
424 */
425
426 static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
427 {
428 rcu_read_lock_bh();
429 return 0;
430 }
431
432 static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
433 {
434 rcu_read_unlock_bh();
435 }
436
437 static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
438 {
439 call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
440 }
441
442 static struct rcu_torture_ops rcu_bh_ops = {
443 .ttype = RCU_BH_FLAVOR,
444 .init = rcu_sync_torture_init,
445 .readlock = rcu_bh_torture_read_lock,
446 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
447 .readunlock = rcu_bh_torture_read_unlock,
448 .started = rcu_batches_started_bh,
449 .completed = rcu_batches_completed_bh,
450 .deferred_free = rcu_bh_torture_deferred_free,
451 .sync = synchronize_rcu_bh,
452 .exp_sync = synchronize_rcu_bh_expedited,
453 .call = call_rcu_bh,
454 .cb_barrier = rcu_barrier_bh,
455 .fqs = rcu_bh_force_quiescent_state,
456 .stats = NULL,
457 .irq_capable = 1,
458 .name = "rcu_bh"
459 };
460
461 /*
462 * Don't even think about trying any of these in real life!!!
463 * The names includes "busted", and they really means it!
464 * The only purpose of these functions is to provide a buggy RCU
465 * implementation to make sure that rcutorture correctly emits
466 * buggy-RCU error messages.
467 */
468 static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
469 {
470 /* This is a deliberate bug for testing purposes only! */
471 rcu_torture_cb(&p->rtort_rcu);
472 }
473
474 static void synchronize_rcu_busted(void)
475 {
476 /* This is a deliberate bug for testing purposes only! */
477 }
478
479 static void
480 call_rcu_busted(struct rcu_head *head, rcu_callback_t func)
481 {
482 /* This is a deliberate bug for testing purposes only! */
483 func(head);
484 }
485
486 static struct rcu_torture_ops rcu_busted_ops = {
487 .ttype = INVALID_RCU_FLAVOR,
488 .init = rcu_sync_torture_init,
489 .readlock = rcu_torture_read_lock,
490 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
491 .readunlock = rcu_torture_read_unlock,
492 .started = rcu_no_completed,
493 .completed = rcu_no_completed,
494 .deferred_free = rcu_busted_torture_deferred_free,
495 .sync = synchronize_rcu_busted,
496 .exp_sync = synchronize_rcu_busted,
497 .call = call_rcu_busted,
498 .cb_barrier = NULL,
499 .fqs = NULL,
500 .stats = NULL,
501 .irq_capable = 1,
502 .name = "busted"
503 };
504
505 /*
506 * Definitions for srcu torture testing.
507 */
508
509 DEFINE_STATIC_SRCU(srcu_ctl);
510 static struct srcu_struct srcu_ctld;
511 static struct srcu_struct *srcu_ctlp = &srcu_ctl;
512
513 static int srcu_torture_read_lock(void) __acquires(srcu_ctlp)
514 {
515 return srcu_read_lock(srcu_ctlp);
516 }
517
518 static void srcu_read_delay(struct torture_random_state *rrsp)
519 {
520 long delay;
521 const long uspertick = 1000000 / HZ;
522 const long longdelay = 10;
523
524 /* We want there to be long-running readers, but not all the time. */
525
526 delay = torture_random(rrsp) %
527 (nrealreaders * 2 * longdelay * uspertick);
528 if (!delay && in_task())
529 schedule_timeout_interruptible(longdelay);
530 else
531 rcu_read_delay(rrsp);
532 }
533
534 static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp)
535 {
536 srcu_read_unlock(srcu_ctlp, idx);
537 }
538
539 static unsigned long srcu_torture_completed(void)
540 {
541 return srcu_batches_completed(srcu_ctlp);
542 }
543
544 static void srcu_torture_deferred_free(struct rcu_torture *rp)
545 {
546 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
547 }
548
549 static void srcu_torture_synchronize(void)
550 {
551 synchronize_srcu(srcu_ctlp);
552 }
553
554 static void srcu_torture_call(struct rcu_head *head,
555 rcu_callback_t func)
556 {
557 call_srcu(srcu_ctlp, head, func);
558 }
559
560 static void srcu_torture_barrier(void)
561 {
562 srcu_barrier(srcu_ctlp);
563 }
564
565 static void srcu_torture_stats(void)
566 {
567 srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG);
568 }
569
570 static void srcu_torture_synchronize_expedited(void)
571 {
572 synchronize_srcu_expedited(srcu_ctlp);
573 }
574
575 static struct rcu_torture_ops srcu_ops = {
576 .ttype = SRCU_FLAVOR,
577 .init = rcu_sync_torture_init,
578 .readlock = srcu_torture_read_lock,
579 .read_delay = srcu_read_delay,
580 .readunlock = srcu_torture_read_unlock,
581 .started = NULL,
582 .completed = srcu_torture_completed,
583 .deferred_free = srcu_torture_deferred_free,
584 .sync = srcu_torture_synchronize,
585 .exp_sync = srcu_torture_synchronize_expedited,
586 .call = srcu_torture_call,
587 .cb_barrier = srcu_torture_barrier,
588 .stats = srcu_torture_stats,
589 .irq_capable = 1,
590 .name = "srcu"
591 };
592
593 static void srcu_torture_init(void)
594 {
595 rcu_sync_torture_init();
596 WARN_ON(init_srcu_struct(&srcu_ctld));
597 srcu_ctlp = &srcu_ctld;
598 }
599
600 static void srcu_torture_cleanup(void)
601 {
602 cleanup_srcu_struct(&srcu_ctld);
603 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
604 }
605
606 /* As above, but dynamically allocated. */
607 static struct rcu_torture_ops srcud_ops = {
608 .ttype = SRCU_FLAVOR,
609 .init = srcu_torture_init,
610 .cleanup = srcu_torture_cleanup,
611 .readlock = srcu_torture_read_lock,
612 .read_delay = srcu_read_delay,
613 .readunlock = srcu_torture_read_unlock,
614 .started = NULL,
615 .completed = srcu_torture_completed,
616 .deferred_free = srcu_torture_deferred_free,
617 .sync = srcu_torture_synchronize,
618 .exp_sync = srcu_torture_synchronize_expedited,
619 .call = srcu_torture_call,
620 .cb_barrier = srcu_torture_barrier,
621 .stats = srcu_torture_stats,
622 .irq_capable = 1,
623 .name = "srcud"
624 };
625
626 /*
627 * Definitions for sched torture testing.
628 */
629
630 static int sched_torture_read_lock(void)
631 {
632 preempt_disable();
633 return 0;
634 }
635
636 static void sched_torture_read_unlock(int idx)
637 {
638 preempt_enable();
639 }
640
641 static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
642 {
643 call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
644 }
645
646 static struct rcu_torture_ops sched_ops = {
647 .ttype = RCU_SCHED_FLAVOR,
648 .init = rcu_sync_torture_init,
649 .readlock = sched_torture_read_lock,
650 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
651 .readunlock = sched_torture_read_unlock,
652 .started = rcu_batches_started_sched,
653 .completed = rcu_batches_completed_sched,
654 .deferred_free = rcu_sched_torture_deferred_free,
655 .sync = synchronize_sched,
656 .exp_sync = synchronize_sched_expedited,
657 .get_state = get_state_synchronize_sched,
658 .cond_sync = cond_synchronize_sched,
659 .call = call_rcu_sched,
660 .cb_barrier = rcu_barrier_sched,
661 .fqs = rcu_sched_force_quiescent_state,
662 .stats = NULL,
663 .irq_capable = 1,
664 .name = "sched"
665 };
666
667 /*
668 * Definitions for RCU-tasks torture testing.
669 */
670
671 static int tasks_torture_read_lock(void)
672 {
673 return 0;
674 }
675
676 static void tasks_torture_read_unlock(int idx)
677 {
678 }
679
680 static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
681 {
682 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
683 }
684
685 static struct rcu_torture_ops tasks_ops = {
686 .ttype = RCU_TASKS_FLAVOR,
687 .init = rcu_sync_torture_init,
688 .readlock = tasks_torture_read_lock,
689 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
690 .readunlock = tasks_torture_read_unlock,
691 .started = rcu_no_completed,
692 .completed = rcu_no_completed,
693 .deferred_free = rcu_tasks_torture_deferred_free,
694 .sync = synchronize_rcu_tasks,
695 .exp_sync = synchronize_rcu_tasks,
696 .call = call_rcu_tasks,
697 .cb_barrier = rcu_barrier_tasks,
698 .fqs = NULL,
699 .stats = NULL,
700 .irq_capable = 1,
701 .name = "tasks"
702 };
703
704 static bool __maybe_unused torturing_tasks(void)
705 {
706 return cur_ops == &tasks_ops;
707 }
708
709 /*
710 * RCU torture priority-boost testing. Runs one real-time thread per
711 * CPU for moderate bursts, repeatedly registering RCU callbacks and
712 * spinning waiting for them to be invoked. If a given callback takes
713 * too long to be invoked, we assume that priority inversion has occurred.
714 */
715
716 struct rcu_boost_inflight {
717 struct rcu_head rcu;
718 int inflight;
719 };
720
721 static void rcu_torture_boost_cb(struct rcu_head *head)
722 {
723 struct rcu_boost_inflight *rbip =
724 container_of(head, struct rcu_boost_inflight, rcu);
725
726 /* Ensure RCU-core accesses precede clearing ->inflight */
727 smp_store_release(&rbip->inflight, 0);
728 }
729
730 static int rcu_torture_boost(void *arg)
731 {
732 unsigned long call_rcu_time;
733 unsigned long endtime;
734 unsigned long oldstarttime;
735 struct rcu_boost_inflight rbi = { .inflight = 0 };
736 struct sched_param sp;
737
738 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
739
740 /* Set real-time priority. */
741 sp.sched_priority = 1;
742 if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
743 VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!");
744 n_rcu_torture_boost_rterror++;
745 }
746
747 init_rcu_head_on_stack(&rbi.rcu);
748 /* Each pass through the following loop does one boost-test cycle. */
749 do {
750 /* Wait for the next test interval. */
751 oldstarttime = boost_starttime;
752 while (ULONG_CMP_LT(jiffies, oldstarttime)) {
753 schedule_timeout_interruptible(oldstarttime - jiffies);
754 stutter_wait("rcu_torture_boost");
755 if (torture_must_stop())
756 goto checkwait;
757 }
758
759 /* Do one boost-test interval. */
760 endtime = oldstarttime + test_boost_duration * HZ;
761 call_rcu_time = jiffies;
762 while (ULONG_CMP_LT(jiffies, endtime)) {
763 /* If we don't have a callback in flight, post one. */
764 if (!smp_load_acquire(&rbi.inflight)) {
765 /* RCU core before ->inflight = 1. */
766 smp_store_release(&rbi.inflight, 1);
767 call_rcu(&rbi.rcu, rcu_torture_boost_cb);
768 if (jiffies - call_rcu_time >
769 test_boost_duration * HZ - HZ / 2) {
770 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
771 n_rcu_torture_boost_failure++;
772 }
773 call_rcu_time = jiffies;
774 }
775 stutter_wait("rcu_torture_boost");
776 if (torture_must_stop())
777 goto checkwait;
778 }
779
780 /*
781 * Set the start time of the next test interval.
782 * Yes, this is vulnerable to long delays, but such
783 * delays simply cause a false negative for the next
784 * interval. Besides, we are running at RT priority,
785 * so delays should be relatively rare.
786 */
787 while (oldstarttime == boost_starttime &&
788 !kthread_should_stop()) {
789 if (mutex_trylock(&boost_mutex)) {
790 boost_starttime = jiffies +
791 test_boost_interval * HZ;
792 n_rcu_torture_boosts++;
793 mutex_unlock(&boost_mutex);
794 break;
795 }
796 schedule_timeout_uninterruptible(1);
797 }
798
799 /* Go do the stutter. */
800 checkwait: stutter_wait("rcu_torture_boost");
801 } while (!torture_must_stop());
802
803 /* Clean up and exit. */
804 while (!kthread_should_stop() || smp_load_acquire(&rbi.inflight)) {
805 torture_shutdown_absorb("rcu_torture_boost");
806 schedule_timeout_uninterruptible(1);
807 }
808 destroy_rcu_head_on_stack(&rbi.rcu);
809 torture_kthread_stopping("rcu_torture_boost");
810 return 0;
811 }
812
813 static void rcu_torture_cbflood_cb(struct rcu_head *rhp)
814 {
815 }
816
817 /*
818 * RCU torture callback-flood kthread. Repeatedly induces bursts of calls
819 * to call_rcu() or analogous, increasing the probability of occurrence
820 * of callback-overflow corner cases.
821 */
822 static int
823 rcu_torture_cbflood(void *arg)
824 {
825 int err = 1;
826 int i;
827 int j;
828 struct rcu_head *rhp;
829
830 if (cbflood_n_per_burst > 0 &&
831 cbflood_inter_holdoff > 0 &&
832 cbflood_intra_holdoff > 0 &&
833 cur_ops->call &&
834 cur_ops->cb_barrier) {
835 rhp = vmalloc(sizeof(*rhp) *
836 cbflood_n_burst * cbflood_n_per_burst);
837 err = !rhp;
838 }
839 if (err) {
840 VERBOSE_TOROUT_STRING("rcu_torture_cbflood disabled: Bad args or OOM");
841 goto wait_for_stop;
842 }
843 VERBOSE_TOROUT_STRING("rcu_torture_cbflood task started");
844 do {
845 schedule_timeout_interruptible(cbflood_inter_holdoff);
846 atomic_long_inc(&n_cbfloods);
847 WARN_ON(signal_pending(current));
848 for (i = 0; i < cbflood_n_burst; i++) {
849 for (j = 0; j < cbflood_n_per_burst; j++) {
850 cur_ops->call(&rhp[i * cbflood_n_per_burst + j],
851 rcu_torture_cbflood_cb);
852 }
853 schedule_timeout_interruptible(cbflood_intra_holdoff);
854 WARN_ON(signal_pending(current));
855 }
856 cur_ops->cb_barrier();
857 stutter_wait("rcu_torture_cbflood");
858 } while (!torture_must_stop());
859 vfree(rhp);
860 wait_for_stop:
861 torture_kthread_stopping("rcu_torture_cbflood");
862 return 0;
863 }
864
865 /*
866 * RCU torture force-quiescent-state kthread. Repeatedly induces
867 * bursts of calls to force_quiescent_state(), increasing the probability
868 * of occurrence of some important types of race conditions.
869 */
870 static int
871 rcu_torture_fqs(void *arg)
872 {
873 unsigned long fqs_resume_time;
874 int fqs_burst_remaining;
875
876 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
877 do {
878 fqs_resume_time = jiffies + fqs_stutter * HZ;
879 while (ULONG_CMP_LT(jiffies, fqs_resume_time) &&
880 !kthread_should_stop()) {
881 schedule_timeout_interruptible(1);
882 }
883 fqs_burst_remaining = fqs_duration;
884 while (fqs_burst_remaining > 0 &&
885 !kthread_should_stop()) {
886 cur_ops->fqs();
887 udelay(fqs_holdoff);
888 fqs_burst_remaining -= fqs_holdoff;
889 }
890 stutter_wait("rcu_torture_fqs");
891 } while (!torture_must_stop());
892 torture_kthread_stopping("rcu_torture_fqs");
893 return 0;
894 }
895
896 /*
897 * RCU torture writer kthread. Repeatedly substitutes a new structure
898 * for that pointed to by rcu_torture_current, freeing the old structure
899 * after a series of grace periods (the "pipeline").
900 */
901 static int
902 rcu_torture_writer(void *arg)
903 {
904 bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
905 int expediting = 0;
906 unsigned long gp_snap;
907 bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal;
908 bool gp_sync1 = gp_sync;
909 int i;
910 struct rcu_torture *rp;
911 struct rcu_torture *old_rp;
912 static DEFINE_TORTURE_RANDOM(rand);
913 int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC,
914 RTWS_COND_GET, RTWS_SYNC };
915 int nsynctypes = 0;
916
917 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
918 if (!can_expedite) {
919 pr_alert("%s" TORTURE_FLAG
920 " GP expediting controlled from boot/sysfs for %s,\n",
921 torture_type, cur_ops->name);
922 pr_alert("%s" TORTURE_FLAG
923 " Disabled dynamic grace-period expediting.\n",
924 torture_type);
925 }
926
927 /* Initialize synctype[] array. If none set, take default. */
928 if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync1)
929 gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true;
930 if (gp_cond1 && cur_ops->get_state && cur_ops->cond_sync)
931 synctype[nsynctypes++] = RTWS_COND_GET;
932 else if (gp_cond && (!cur_ops->get_state || !cur_ops->cond_sync))
933 pr_alert("rcu_torture_writer: gp_cond without primitives.\n");
934 if (gp_exp1 && cur_ops->exp_sync)
935 synctype[nsynctypes++] = RTWS_EXP_SYNC;
936 else if (gp_exp && !cur_ops->exp_sync)
937 pr_alert("rcu_torture_writer: gp_exp without primitives.\n");
938 if (gp_normal1 && cur_ops->deferred_free)
939 synctype[nsynctypes++] = RTWS_DEF_FREE;
940 else if (gp_normal && !cur_ops->deferred_free)
941 pr_alert("rcu_torture_writer: gp_normal without primitives.\n");
942 if (gp_sync1 && cur_ops->sync)
943 synctype[nsynctypes++] = RTWS_SYNC;
944 else if (gp_sync && !cur_ops->sync)
945 pr_alert("rcu_torture_writer: gp_sync without primitives.\n");
946 if (WARN_ONCE(nsynctypes == 0,
947 "rcu_torture_writer: No update-side primitives.\n")) {
948 /*
949 * No updates primitives, so don't try updating.
950 * The resulting test won't be testing much, hence the
951 * above WARN_ONCE().
952 */
953 rcu_torture_writer_state = RTWS_STOPPING;
954 torture_kthread_stopping("rcu_torture_writer");
955 }
956
957 do {
958 rcu_torture_writer_state = RTWS_FIXED_DELAY;
959 schedule_timeout_uninterruptible(1);
960 rp = rcu_torture_alloc();
961 if (rp == NULL)
962 continue;
963 rp->rtort_pipe_count = 0;
964 rcu_torture_writer_state = RTWS_DELAY;
965 udelay(torture_random(&rand) & 0x3ff);
966 rcu_torture_writer_state = RTWS_REPLACE;
967 old_rp = rcu_dereference_check(rcu_torture_current,
968 current == writer_task);
969 rp->rtort_mbtest = 1;
970 rcu_assign_pointer(rcu_torture_current, rp);
971 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
972 if (old_rp) {
973 i = old_rp->rtort_pipe_count;
974 if (i > RCU_TORTURE_PIPE_LEN)
975 i = RCU_TORTURE_PIPE_LEN;
976 atomic_inc(&rcu_torture_wcount[i]);
977 old_rp->rtort_pipe_count++;
978 switch (synctype[torture_random(&rand) % nsynctypes]) {
979 case RTWS_DEF_FREE:
980 rcu_torture_writer_state = RTWS_DEF_FREE;
981 cur_ops->deferred_free(old_rp);
982 break;
983 case RTWS_EXP_SYNC:
984 rcu_torture_writer_state = RTWS_EXP_SYNC;
985 cur_ops->exp_sync();
986 rcu_torture_pipe_update(old_rp);
987 break;
988 case RTWS_COND_GET:
989 rcu_torture_writer_state = RTWS_COND_GET;
990 gp_snap = cur_ops->get_state();
991 i = torture_random(&rand) % 16;
992 if (i != 0)
993 schedule_timeout_interruptible(i);
994 udelay(torture_random(&rand) % 1000);
995 rcu_torture_writer_state = RTWS_COND_SYNC;
996 cur_ops->cond_sync(gp_snap);
997 rcu_torture_pipe_update(old_rp);
998 break;
999 case RTWS_SYNC:
1000 rcu_torture_writer_state = RTWS_SYNC;
1001 cur_ops->sync();
1002 rcu_torture_pipe_update(old_rp);
1003 break;
1004 default:
1005 WARN_ON_ONCE(1);
1006 break;
1007 }
1008 }
1009 rcutorture_record_progress(++rcu_torture_current_version);
1010 /* Cycle through nesting levels of rcu_expedite_gp() calls. */
1011 if (can_expedite &&
1012 !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
1013 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
1014 if (expediting >= 0)
1015 rcu_expedite_gp();
1016 else
1017 rcu_unexpedite_gp();
1018 if (++expediting > 3)
1019 expediting = -expediting;
1020 }
1021 rcu_torture_writer_state = RTWS_STUTTER;
1022 stutter_wait("rcu_torture_writer");
1023 } while (!torture_must_stop());
1024 /* Reset expediting back to unexpedited. */
1025 if (expediting > 0)
1026 expediting = -expediting;
1027 while (can_expedite && expediting++ < 0)
1028 rcu_unexpedite_gp();
1029 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
1030 rcu_torture_writer_state = RTWS_STOPPING;
1031 torture_kthread_stopping("rcu_torture_writer");
1032 return 0;
1033 }
1034
1035 /*
1036 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
1037 * delay between calls.
1038 */
1039 static int
1040 rcu_torture_fakewriter(void *arg)
1041 {
1042 DEFINE_TORTURE_RANDOM(rand);
1043
1044 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1045 set_user_nice(current, MAX_NICE);
1046
1047 do {
1048 schedule_timeout_uninterruptible(1 + torture_random(&rand)%10);
1049 udelay(torture_random(&rand) & 0x3ff);
1050 if (cur_ops->cb_barrier != NULL &&
1051 torture_random(&rand) % (nfakewriters * 8) == 0) {
1052 cur_ops->cb_barrier();
1053 } else if (gp_normal == gp_exp) {
1054 if (torture_random(&rand) & 0x80)
1055 cur_ops->sync();
1056 else
1057 cur_ops->exp_sync();
1058 } else if (gp_normal) {
1059 cur_ops->sync();
1060 } else {
1061 cur_ops->exp_sync();
1062 }
1063 stutter_wait("rcu_torture_fakewriter");
1064 } while (!torture_must_stop());
1065
1066 torture_kthread_stopping("rcu_torture_fakewriter");
1067 return 0;
1068 }
1069
1070 static void rcu_torture_timer_cb(struct rcu_head *rhp)
1071 {
1072 kfree(rhp);
1073 }
1074
1075 /*
1076 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
1077 * incrementing the corresponding element of the pipeline array. The
1078 * counter in the element should never be greater than 1, otherwise, the
1079 * RCU implementation is broken.
1080 */
1081 static void rcu_torture_timer(struct timer_list *unused)
1082 {
1083 int idx;
1084 unsigned long started;
1085 unsigned long completed;
1086 static DEFINE_TORTURE_RANDOM(rand);
1087 static DEFINE_SPINLOCK(rand_lock);
1088 struct rcu_torture *p;
1089 int pipe_count;
1090 unsigned long long ts;
1091
1092 idx = cur_ops->readlock();
1093 if (cur_ops->started)
1094 started = cur_ops->started();
1095 else
1096 started = cur_ops->completed();
1097 ts = rcu_trace_clock_local();
1098 p = rcu_dereference_check(rcu_torture_current,
1099 rcu_read_lock_bh_held() ||
1100 rcu_read_lock_sched_held() ||
1101 srcu_read_lock_held(srcu_ctlp) ||
1102 torturing_tasks());
1103 if (p == NULL) {
1104 /* Leave because rcu_torture_writer is not yet underway */
1105 cur_ops->readunlock(idx);
1106 return;
1107 }
1108 if (p->rtort_mbtest == 0)
1109 atomic_inc(&n_rcu_torture_mberror);
1110 spin_lock(&rand_lock);
1111 cur_ops->read_delay(&rand);
1112 n_rcu_torture_timers++;
1113 spin_unlock(&rand_lock);
1114 preempt_disable();
1115 pipe_count = p->rtort_pipe_count;
1116 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1117 /* Should not happen, but... */
1118 pipe_count = RCU_TORTURE_PIPE_LEN;
1119 }
1120 completed = cur_ops->completed();
1121 if (pipe_count > 1) {
1122 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, ts,
1123 started, completed);
1124 rcu_ftrace_dump(DUMP_ALL);
1125 }
1126 __this_cpu_inc(rcu_torture_count[pipe_count]);
1127 completed = completed - started;
1128 if (cur_ops->started)
1129 completed++;
1130 if (completed > RCU_TORTURE_PIPE_LEN) {
1131 /* Should not happen, but... */
1132 completed = RCU_TORTURE_PIPE_LEN;
1133 }
1134 __this_cpu_inc(rcu_torture_batch[completed]);
1135 preempt_enable();
1136 cur_ops->readunlock(idx);
1137
1138 /* Test call_rcu() invocation from interrupt handler. */
1139 if (cur_ops->call) {
1140 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT);
1141
1142 if (rhp)
1143 cur_ops->call(rhp, rcu_torture_timer_cb);
1144 }
1145 }
1146
1147 /*
1148 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
1149 * incrementing the corresponding element of the pipeline array. The
1150 * counter in the element should never be greater than 1, otherwise, the
1151 * RCU implementation is broken.
1152 */
1153 static int
1154 rcu_torture_reader(void *arg)
1155 {
1156 unsigned long started;
1157 unsigned long completed;
1158 int idx;
1159 DEFINE_TORTURE_RANDOM(rand);
1160 struct rcu_torture *p;
1161 int pipe_count;
1162 struct timer_list t;
1163 unsigned long long ts;
1164
1165 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
1166 set_user_nice(current, MAX_NICE);
1167 if (irqreader && cur_ops->irq_capable)
1168 timer_setup_on_stack(&t, rcu_torture_timer, 0);
1169
1170 do {
1171 if (irqreader && cur_ops->irq_capable) {
1172 if (!timer_pending(&t))
1173 mod_timer(&t, jiffies + 1);
1174 }
1175 idx = cur_ops->readlock();
1176 if (cur_ops->started)
1177 started = cur_ops->started();
1178 else
1179 started = cur_ops->completed();
1180 ts = rcu_trace_clock_local();
1181 p = rcu_dereference_check(rcu_torture_current,
1182 rcu_read_lock_bh_held() ||
1183 rcu_read_lock_sched_held() ||
1184 srcu_read_lock_held(srcu_ctlp) ||
1185 torturing_tasks());
1186 if (p == NULL) {
1187 /* Wait for rcu_torture_writer to get underway */
1188 cur_ops->readunlock(idx);
1189 schedule_timeout_interruptible(HZ);
1190 continue;
1191 }
1192 if (p->rtort_mbtest == 0)
1193 atomic_inc(&n_rcu_torture_mberror);
1194 cur_ops->read_delay(&rand);
1195 preempt_disable();
1196 pipe_count = p->rtort_pipe_count;
1197 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1198 /* Should not happen, but... */
1199 pipe_count = RCU_TORTURE_PIPE_LEN;
1200 }
1201 completed = cur_ops->completed();
1202 if (pipe_count > 1) {
1203 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
1204 ts, started, completed);
1205 rcu_ftrace_dump(DUMP_ALL);
1206 }
1207 __this_cpu_inc(rcu_torture_count[pipe_count]);
1208 completed = completed - started;
1209 if (cur_ops->started)
1210 completed++;
1211 if (completed > RCU_TORTURE_PIPE_LEN) {
1212 /* Should not happen, but... */
1213 completed = RCU_TORTURE_PIPE_LEN;
1214 }
1215 __this_cpu_inc(rcu_torture_batch[completed]);
1216 preempt_enable();
1217 cur_ops->readunlock(idx);
1218 stutter_wait("rcu_torture_reader");
1219 } while (!torture_must_stop());
1220 if (irqreader && cur_ops->irq_capable) {
1221 del_timer_sync(&t);
1222 destroy_timer_on_stack(&t);
1223 }
1224 torture_kthread_stopping("rcu_torture_reader");
1225 return 0;
1226 }
1227
1228 /*
1229 * Print torture statistics. Caller must ensure that there is only
1230 * one call to this function at a given time!!! This is normally
1231 * accomplished by relying on the module system to only have one copy
1232 * of the module loaded, and then by giving the rcu_torture_stats
1233 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1234 * thread is not running).
1235 */
1236 static void
1237 rcu_torture_stats_print(void)
1238 {
1239 int cpu;
1240 int i;
1241 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1242 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1243 static unsigned long rtcv_snap = ULONG_MAX;
1244 static bool splatted;
1245 struct task_struct *wtp;
1246
1247 for_each_possible_cpu(cpu) {
1248 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1249 pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
1250 batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
1251 }
1252 }
1253 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
1254 if (pipesummary[i] != 0)
1255 break;
1256 }
1257
1258 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1259 pr_cont("rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
1260 rcu_torture_current,
1261 rcu_torture_current_version,
1262 list_empty(&rcu_torture_freelist),
1263 atomic_read(&n_rcu_torture_alloc),
1264 atomic_read(&n_rcu_torture_alloc_fail),
1265 atomic_read(&n_rcu_torture_free));
1266 pr_cont("rtmbe: %d rtbe: %ld rtbke: %ld rtbre: %ld ",
1267 atomic_read(&n_rcu_torture_mberror),
1268 n_rcu_torture_barrier_error,
1269 n_rcu_torture_boost_ktrerror,
1270 n_rcu_torture_boost_rterror);
1271 pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
1272 n_rcu_torture_boost_failure,
1273 n_rcu_torture_boosts,
1274 n_rcu_torture_timers);
1275 torture_onoff_stats();
1276 pr_cont("barrier: %ld/%ld:%ld ",
1277 n_barrier_successes,
1278 n_barrier_attempts,
1279 n_rcu_torture_barrier_error);
1280 pr_cont("cbflood: %ld\n", atomic_long_read(&n_cbfloods));
1281
1282 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1283 if (atomic_read(&n_rcu_torture_mberror) != 0 ||
1284 n_rcu_torture_barrier_error != 0 ||
1285 n_rcu_torture_boost_ktrerror != 0 ||
1286 n_rcu_torture_boost_rterror != 0 ||
1287 n_rcu_torture_boost_failure != 0 ||
1288 i > 1) {
1289 pr_cont("%s", "!!! ");
1290 atomic_inc(&n_rcu_torture_error);
1291 WARN_ON_ONCE(1);
1292 }
1293 pr_cont("Reader Pipe: ");
1294 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1295 pr_cont(" %ld", pipesummary[i]);
1296 pr_cont("\n");
1297
1298 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1299 pr_cont("Reader Batch: ");
1300 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1301 pr_cont(" %ld", batchsummary[i]);
1302 pr_cont("\n");
1303
1304 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1305 pr_cont("Free-Block Circulation: ");
1306 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1307 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
1308 }
1309 pr_cont("\n");
1310
1311 if (cur_ops->stats)
1312 cur_ops->stats();
1313 if (rtcv_snap == rcu_torture_current_version &&
1314 rcu_torture_current != NULL) {
1315 int __maybe_unused flags = 0;
1316 unsigned long __maybe_unused gpnum = 0;
1317 unsigned long __maybe_unused completed = 0;
1318
1319 rcutorture_get_gp_data(cur_ops->ttype,
1320 &flags, &gpnum, &completed);
1321 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp,
1322 &flags, &gpnum, &completed);
1323 wtp = READ_ONCE(writer_task);
1324 pr_alert("??? Writer stall state %s(%d) g%lu c%lu f%#x ->state %#lx cpu %d\n",
1325 rcu_torture_writer_state_getname(),
1326 rcu_torture_writer_state,
1327 gpnum, completed, flags,
1328 wtp == NULL ? ~0UL : wtp->state,
1329 wtp == NULL ? -1 : (int)task_cpu(wtp));
1330 if (!splatted && wtp) {
1331 sched_show_task(wtp);
1332 splatted = true;
1333 }
1334 show_rcu_gp_kthreads();
1335 rcu_ftrace_dump(DUMP_ALL);
1336 }
1337 rtcv_snap = rcu_torture_current_version;
1338 }
1339
1340 /*
1341 * Periodically prints torture statistics, if periodic statistics printing
1342 * was specified via the stat_interval module parameter.
1343 */
1344 static int
1345 rcu_torture_stats(void *arg)
1346 {
1347 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1348 do {
1349 schedule_timeout_interruptible(stat_interval * HZ);
1350 rcu_torture_stats_print();
1351 torture_shutdown_absorb("rcu_torture_stats");
1352 } while (!torture_must_stop());
1353 torture_kthread_stopping("rcu_torture_stats");
1354 return 0;
1355 }
1356
1357 static inline void
1358 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1359 {
1360 pr_alert("%s" TORTURE_FLAG
1361 "--- %s: nreaders=%d nfakewriters=%d "
1362 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1363 "shuffle_interval=%d stutter=%d irqreader=%d "
1364 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1365 "test_boost=%d/%d test_boost_interval=%d "
1366 "test_boost_duration=%d shutdown_secs=%d "
1367 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d "
1368 "n_barrier_cbs=%d "
1369 "onoff_interval=%d onoff_holdoff=%d\n",
1370 torture_type, tag, nrealreaders, nfakewriters,
1371 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1372 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1373 test_boost, cur_ops->can_boost,
1374 test_boost_interval, test_boost_duration, shutdown_secs,
1375 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff,
1376 n_barrier_cbs,
1377 onoff_interval, onoff_holdoff);
1378 }
1379
1380 static int rcutorture_booster_cleanup(unsigned int cpu)
1381 {
1382 struct task_struct *t;
1383
1384 if (boost_tasks[cpu] == NULL)
1385 return 0;
1386 mutex_lock(&boost_mutex);
1387 t = boost_tasks[cpu];
1388 boost_tasks[cpu] = NULL;
1389 mutex_unlock(&boost_mutex);
1390
1391 /* This must be outside of the mutex, otherwise deadlock! */
1392 torture_stop_kthread(rcu_torture_boost, t);
1393 return 0;
1394 }
1395
1396 static int rcutorture_booster_init(unsigned int cpu)
1397 {
1398 int retval;
1399
1400 if (boost_tasks[cpu] != NULL)
1401 return 0; /* Already created, nothing more to do. */
1402
1403 /* Don't allow time recalculation while creating a new task. */
1404 mutex_lock(&boost_mutex);
1405 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
1406 boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
1407 cpu_to_node(cpu),
1408 "rcu_torture_boost");
1409 if (IS_ERR(boost_tasks[cpu])) {
1410 retval = PTR_ERR(boost_tasks[cpu]);
1411 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
1412 n_rcu_torture_boost_ktrerror++;
1413 boost_tasks[cpu] = NULL;
1414 mutex_unlock(&boost_mutex);
1415 return retval;
1416 }
1417 kthread_bind(boost_tasks[cpu], cpu);
1418 wake_up_process(boost_tasks[cpu]);
1419 mutex_unlock(&boost_mutex);
1420 return 0;
1421 }
1422
1423 /*
1424 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
1425 * induces a CPU stall for the time specified by stall_cpu.
1426 */
1427 static int rcu_torture_stall(void *args)
1428 {
1429 unsigned long stop_at;
1430
1431 VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
1432 if (stall_cpu_holdoff > 0) {
1433 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
1434 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
1435 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
1436 }
1437 if (!kthread_should_stop()) {
1438 stop_at = get_seconds() + stall_cpu;
1439 /* RCU CPU stall is expected behavior in following code. */
1440 rcu_read_lock();
1441 if (stall_cpu_irqsoff)
1442 local_irq_disable();
1443 else
1444 preempt_disable();
1445 pr_alert("rcu_torture_stall start on CPU %d.\n",
1446 smp_processor_id());
1447 while (ULONG_CMP_LT(get_seconds(), stop_at))
1448 continue; /* Induce RCU CPU stall warning. */
1449 if (stall_cpu_irqsoff)
1450 local_irq_enable();
1451 else
1452 preempt_enable();
1453 rcu_read_unlock();
1454 pr_alert("rcu_torture_stall end.\n");
1455 }
1456 torture_shutdown_absorb("rcu_torture_stall");
1457 while (!kthread_should_stop())
1458 schedule_timeout_interruptible(10 * HZ);
1459 return 0;
1460 }
1461
1462 /* Spawn CPU-stall kthread, if stall_cpu specified. */
1463 static int __init rcu_torture_stall_init(void)
1464 {
1465 if (stall_cpu <= 0)
1466 return 0;
1467 return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
1468 }
1469
1470 /* Callback function for RCU barrier testing. */
1471 static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
1472 {
1473 atomic_inc(&barrier_cbs_invoked);
1474 }
1475
1476 /* kthread function to register callbacks used to test RCU barriers. */
1477 static int rcu_torture_barrier_cbs(void *arg)
1478 {
1479 long myid = (long)arg;
1480 bool lastphase = 0;
1481 bool newphase;
1482 struct rcu_head rcu;
1483
1484 init_rcu_head_on_stack(&rcu);
1485 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
1486 set_user_nice(current, MAX_NICE);
1487 do {
1488 wait_event(barrier_cbs_wq[myid],
1489 (newphase =
1490 smp_load_acquire(&barrier_phase)) != lastphase ||
1491 torture_must_stop());
1492 lastphase = newphase;
1493 if (torture_must_stop())
1494 break;
1495 /*
1496 * The above smp_load_acquire() ensures barrier_phase load
1497 * is ordered before the following ->call().
1498 */
1499 local_irq_disable(); /* Just to test no-irq call_rcu(). */
1500 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
1501 local_irq_enable();
1502 if (atomic_dec_and_test(&barrier_cbs_count))
1503 wake_up(&barrier_wq);
1504 } while (!torture_must_stop());
1505 if (cur_ops->cb_barrier != NULL)
1506 cur_ops->cb_barrier();
1507 destroy_rcu_head_on_stack(&rcu);
1508 torture_kthread_stopping("rcu_torture_barrier_cbs");
1509 return 0;
1510 }
1511
1512 /* kthread function to drive and coordinate RCU barrier testing. */
1513 static int rcu_torture_barrier(void *arg)
1514 {
1515 int i;
1516
1517 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
1518 do {
1519 atomic_set(&barrier_cbs_invoked, 0);
1520 atomic_set(&barrier_cbs_count, n_barrier_cbs);
1521 /* Ensure barrier_phase ordered after prior assignments. */
1522 smp_store_release(&barrier_phase, !barrier_phase);
1523 for (i = 0; i < n_barrier_cbs; i++)
1524 wake_up(&barrier_cbs_wq[i]);
1525 wait_event(barrier_wq,
1526 atomic_read(&barrier_cbs_count) == 0 ||
1527 torture_must_stop());
1528 if (torture_must_stop())
1529 break;
1530 n_barrier_attempts++;
1531 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
1532 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
1533 n_rcu_torture_barrier_error++;
1534 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
1535 atomic_read(&barrier_cbs_invoked),
1536 n_barrier_cbs);
1537 WARN_ON_ONCE(1);
1538 }
1539 n_barrier_successes++;
1540 schedule_timeout_interruptible(HZ / 10);
1541 } while (!torture_must_stop());
1542 torture_kthread_stopping("rcu_torture_barrier");
1543 return 0;
1544 }
1545
1546 /* Initialize RCU barrier testing. */
1547 static int rcu_torture_barrier_init(void)
1548 {
1549 int i;
1550 int ret;
1551
1552 if (n_barrier_cbs <= 0)
1553 return 0;
1554 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
1555 pr_alert("%s" TORTURE_FLAG
1556 " Call or barrier ops missing for %s,\n",
1557 torture_type, cur_ops->name);
1558 pr_alert("%s" TORTURE_FLAG
1559 " RCU barrier testing omitted from run.\n",
1560 torture_type);
1561 return 0;
1562 }
1563 atomic_set(&barrier_cbs_count, 0);
1564 atomic_set(&barrier_cbs_invoked, 0);
1565 barrier_cbs_tasks =
1566 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_tasks[0]),
1567 GFP_KERNEL);
1568 barrier_cbs_wq =
1569 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_wq[0]),
1570 GFP_KERNEL);
1571 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
1572 return -ENOMEM;
1573 for (i = 0; i < n_barrier_cbs; i++) {
1574 init_waitqueue_head(&barrier_cbs_wq[i]);
1575 ret = torture_create_kthread(rcu_torture_barrier_cbs,
1576 (void *)(long)i,
1577 barrier_cbs_tasks[i]);
1578 if (ret)
1579 return ret;
1580 }
1581 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
1582 }
1583
1584 /* Clean up after RCU barrier testing. */
1585 static void rcu_torture_barrier_cleanup(void)
1586 {
1587 int i;
1588
1589 torture_stop_kthread(rcu_torture_barrier, barrier_task);
1590 if (barrier_cbs_tasks != NULL) {
1591 for (i = 0; i < n_barrier_cbs; i++)
1592 torture_stop_kthread(rcu_torture_barrier_cbs,
1593 barrier_cbs_tasks[i]);
1594 kfree(barrier_cbs_tasks);
1595 barrier_cbs_tasks = NULL;
1596 }
1597 if (barrier_cbs_wq != NULL) {
1598 kfree(barrier_cbs_wq);
1599 barrier_cbs_wq = NULL;
1600 }
1601 }
1602
1603 static enum cpuhp_state rcutor_hp;
1604
1605 static void
1606 rcu_torture_cleanup(void)
1607 {
1608 int i;
1609
1610 rcutorture_record_test_transition();
1611 if (torture_cleanup_begin()) {
1612 if (cur_ops->cb_barrier != NULL)
1613 cur_ops->cb_barrier();
1614 return;
1615 }
1616
1617 rcu_torture_barrier_cleanup();
1618 torture_stop_kthread(rcu_torture_stall, stall_task);
1619 torture_stop_kthread(rcu_torture_writer, writer_task);
1620
1621 if (reader_tasks) {
1622 for (i = 0; i < nrealreaders; i++)
1623 torture_stop_kthread(rcu_torture_reader,
1624 reader_tasks[i]);
1625 kfree(reader_tasks);
1626 }
1627 rcu_torture_current = NULL;
1628
1629 if (fakewriter_tasks) {
1630 for (i = 0; i < nfakewriters; i++) {
1631 torture_stop_kthread(rcu_torture_fakewriter,
1632 fakewriter_tasks[i]);
1633 }
1634 kfree(fakewriter_tasks);
1635 fakewriter_tasks = NULL;
1636 }
1637
1638 torture_stop_kthread(rcu_torture_stats, stats_task);
1639 torture_stop_kthread(rcu_torture_fqs, fqs_task);
1640 for (i = 0; i < ncbflooders; i++)
1641 torture_stop_kthread(rcu_torture_cbflood, cbflood_task[i]);
1642 if ((test_boost == 1 && cur_ops->can_boost) ||
1643 test_boost == 2)
1644 cpuhp_remove_state(rcutor_hp);
1645
1646 /*
1647 * Wait for all RCU callbacks to fire, then do flavor-specific
1648 * cleanup operations.
1649 */
1650 if (cur_ops->cb_barrier != NULL)
1651 cur_ops->cb_barrier();
1652 if (cur_ops->cleanup != NULL)
1653 cur_ops->cleanup();
1654
1655 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
1656
1657 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
1658 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
1659 else if (torture_onoff_failures())
1660 rcu_torture_print_module_parms(cur_ops,
1661 "End of test: RCU_HOTPLUG");
1662 else
1663 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
1664 torture_cleanup_end();
1665 }
1666
1667 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1668 static void rcu_torture_leak_cb(struct rcu_head *rhp)
1669 {
1670 }
1671
1672 static void rcu_torture_err_cb(struct rcu_head *rhp)
1673 {
1674 /*
1675 * This -might- happen due to race conditions, but is unlikely.
1676 * The scenario that leads to this happening is that the
1677 * first of the pair of duplicate callbacks is queued,
1678 * someone else starts a grace period that includes that
1679 * callback, then the second of the pair must wait for the
1680 * next grace period. Unlikely, but can happen. If it
1681 * does happen, the debug-objects subsystem won't have splatted.
1682 */
1683 pr_alert("rcutorture: duplicated callback was invoked.\n");
1684 }
1685 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1686
1687 /*
1688 * Verify that double-free causes debug-objects to complain, but only
1689 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
1690 * cannot be carried out.
1691 */
1692 static void rcu_test_debug_objects(void)
1693 {
1694 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1695 struct rcu_head rh1;
1696 struct rcu_head rh2;
1697
1698 init_rcu_head_on_stack(&rh1);
1699 init_rcu_head_on_stack(&rh2);
1700 pr_alert("rcutorture: WARN: Duplicate call_rcu() test starting.\n");
1701
1702 /* Try to queue the rh2 pair of callbacks for the same grace period. */
1703 preempt_disable(); /* Prevent preemption from interrupting test. */
1704 rcu_read_lock(); /* Make it impossible to finish a grace period. */
1705 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
1706 local_irq_disable(); /* Make it harder to start a new grace period. */
1707 call_rcu(&rh2, rcu_torture_leak_cb);
1708 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
1709 local_irq_enable();
1710 rcu_read_unlock();
1711 preempt_enable();
1712
1713 /* Wait for them all to get done so we can safely return. */
1714 rcu_barrier();
1715 pr_alert("rcutorture: WARN: Duplicate call_rcu() test complete.\n");
1716 destroy_rcu_head_on_stack(&rh1);
1717 destroy_rcu_head_on_stack(&rh2);
1718 #else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1719 pr_alert("rcutorture: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n");
1720 #endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1721 }
1722
1723 static int __init
1724 rcu_torture_init(void)
1725 {
1726 int i;
1727 int cpu;
1728 int firsterr = 0;
1729 static struct rcu_torture_ops *torture_ops[] = {
1730 &rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops,
1731 &sched_ops, &tasks_ops,
1732 };
1733
1734 if (!torture_init_begin(torture_type, verbose, &torture_runnable))
1735 return -EBUSY;
1736
1737 /* Process args and tell the world that the torturer is on the job. */
1738 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1739 cur_ops = torture_ops[i];
1740 if (strcmp(torture_type, cur_ops->name) == 0)
1741 break;
1742 }
1743 if (i == ARRAY_SIZE(torture_ops)) {
1744 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
1745 torture_type);
1746 pr_alert("rcu-torture types:");
1747 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1748 pr_alert(" %s", torture_ops[i]->name);
1749 pr_alert("\n");
1750 firsterr = -EINVAL;
1751 goto unwind;
1752 }
1753 if (cur_ops->fqs == NULL && fqs_duration != 0) {
1754 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
1755 fqs_duration = 0;
1756 }
1757 if (cur_ops->init)
1758 cur_ops->init();
1759
1760 if (nreaders >= 0) {
1761 nrealreaders = nreaders;
1762 } else {
1763 nrealreaders = num_online_cpus() - 2 - nreaders;
1764 if (nrealreaders <= 0)
1765 nrealreaders = 1;
1766 }
1767 rcu_torture_print_module_parms(cur_ops, "Start of test");
1768
1769 /* Set up the freelist. */
1770
1771 INIT_LIST_HEAD(&rcu_torture_freelist);
1772 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1773 rcu_tortures[i].rtort_mbtest = 0;
1774 list_add_tail(&rcu_tortures[i].rtort_free,
1775 &rcu_torture_freelist);
1776 }
1777
1778 /* Initialize the statistics so that each run gets its own numbers. */
1779
1780 rcu_torture_current = NULL;
1781 rcu_torture_current_version = 0;
1782 atomic_set(&n_rcu_torture_alloc, 0);
1783 atomic_set(&n_rcu_torture_alloc_fail, 0);
1784 atomic_set(&n_rcu_torture_free, 0);
1785 atomic_set(&n_rcu_torture_mberror, 0);
1786 atomic_set(&n_rcu_torture_error, 0);
1787 n_rcu_torture_barrier_error = 0;
1788 n_rcu_torture_boost_ktrerror = 0;
1789 n_rcu_torture_boost_rterror = 0;
1790 n_rcu_torture_boost_failure = 0;
1791 n_rcu_torture_boosts = 0;
1792 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1793 atomic_set(&rcu_torture_wcount[i], 0);
1794 for_each_possible_cpu(cpu) {
1795 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1796 per_cpu(rcu_torture_count, cpu)[i] = 0;
1797 per_cpu(rcu_torture_batch, cpu)[i] = 0;
1798 }
1799 }
1800
1801 /* Start up the kthreads. */
1802
1803 firsterr = torture_create_kthread(rcu_torture_writer, NULL,
1804 writer_task);
1805 if (firsterr)
1806 goto unwind;
1807 if (nfakewriters > 0) {
1808 fakewriter_tasks = kzalloc(nfakewriters *
1809 sizeof(fakewriter_tasks[0]),
1810 GFP_KERNEL);
1811 if (fakewriter_tasks == NULL) {
1812 VERBOSE_TOROUT_ERRSTRING("out of memory");
1813 firsterr = -ENOMEM;
1814 goto unwind;
1815 }
1816 }
1817 for (i = 0; i < nfakewriters; i++) {
1818 firsterr = torture_create_kthread(rcu_torture_fakewriter,
1819 NULL, fakewriter_tasks[i]);
1820 if (firsterr)
1821 goto unwind;
1822 }
1823 reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
1824 GFP_KERNEL);
1825 if (reader_tasks == NULL) {
1826 VERBOSE_TOROUT_ERRSTRING("out of memory");
1827 firsterr = -ENOMEM;
1828 goto unwind;
1829 }
1830 for (i = 0; i < nrealreaders; i++) {
1831 firsterr = torture_create_kthread(rcu_torture_reader, NULL,
1832 reader_tasks[i]);
1833 if (firsterr)
1834 goto unwind;
1835 }
1836 if (stat_interval > 0) {
1837 firsterr = torture_create_kthread(rcu_torture_stats, NULL,
1838 stats_task);
1839 if (firsterr)
1840 goto unwind;
1841 }
1842 if (test_no_idle_hz && shuffle_interval > 0) {
1843 firsterr = torture_shuffle_init(shuffle_interval * HZ);
1844 if (firsterr)
1845 goto unwind;
1846 }
1847 if (stutter < 0)
1848 stutter = 0;
1849 if (stutter) {
1850 firsterr = torture_stutter_init(stutter * HZ);
1851 if (firsterr)
1852 goto unwind;
1853 }
1854 if (fqs_duration < 0)
1855 fqs_duration = 0;
1856 if (fqs_duration) {
1857 /* Create the fqs thread */
1858 firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
1859 fqs_task);
1860 if (firsterr)
1861 goto unwind;
1862 }
1863 if (test_boost_interval < 1)
1864 test_boost_interval = 1;
1865 if (test_boost_duration < 2)
1866 test_boost_duration = 2;
1867 if ((test_boost == 1 && cur_ops->can_boost) ||
1868 test_boost == 2) {
1869
1870 boost_starttime = jiffies + test_boost_interval * HZ;
1871
1872 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE",
1873 rcutorture_booster_init,
1874 rcutorture_booster_cleanup);
1875 if (firsterr < 0)
1876 goto unwind;
1877 rcutor_hp = firsterr;
1878 }
1879 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
1880 if (firsterr)
1881 goto unwind;
1882 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval * HZ);
1883 if (firsterr)
1884 goto unwind;
1885 firsterr = rcu_torture_stall_init();
1886 if (firsterr)
1887 goto unwind;
1888 firsterr = rcu_torture_barrier_init();
1889 if (firsterr)
1890 goto unwind;
1891 if (object_debug)
1892 rcu_test_debug_objects();
1893 if (cbflood_n_burst > 0) {
1894 /* Create the cbflood threads */
1895 ncbflooders = (num_online_cpus() + 3) / 4;
1896 cbflood_task = kcalloc(ncbflooders, sizeof(*cbflood_task),
1897 GFP_KERNEL);
1898 if (!cbflood_task) {
1899 VERBOSE_TOROUT_ERRSTRING("out of memory");
1900 firsterr = -ENOMEM;
1901 goto unwind;
1902 }
1903 for (i = 0; i < ncbflooders; i++) {
1904 firsterr = torture_create_kthread(rcu_torture_cbflood,
1905 NULL,
1906 cbflood_task[i]);
1907 if (firsterr)
1908 goto unwind;
1909 }
1910 }
1911 rcutorture_record_test_transition();
1912 torture_init_end();
1913 return 0;
1914
1915 unwind:
1916 torture_init_end();
1917 rcu_torture_cleanup();
1918 return firsterr;
1919 }
1920
1921 module_init(rcu_torture_init);
1922 module_exit(rcu_torture_cleanup);
Linux with added FPC-III support