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x86/dumpstack: Remove extra brackets around "<EOE>"
[linux/fpc-iii.git] / kernel / rcu / rcutorture.c
blob971e2b138063a6920a96adc1f21e65619746a04b
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.h>
36 #include <linux/atomic.h>
37 #include <linux/bitops.h>
38 #include <linux/completion.h>
39 #include <linux/moduleparam.h>
40 #include <linux/percpu.h>
41 #include <linux/notifier.h>
42 #include <linux/reboot.h>
43 #include <linux/freezer.h>
44 #include <linux/cpu.h>
45 #include <linux/delay.h>
46 #include <linux/stat.h>
47 #include <linux/srcu.h>
48 #include <linux/slab.h>
49 #include <linux/trace_clock.h>
50 #include <asm/byteorder.h>
51 #include <linux/torture.h>
52 #include <linux/vmalloc.h>
53
54 MODULE_LICENSE("GPL");
55 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
56
57
58 torture_param(int, cbflood_inter_holdoff, HZ,
59 "Holdoff between floods (jiffies)");
60 torture_param(int, cbflood_intra_holdoff, 1,
61 "Holdoff between bursts (jiffies)");
62 torture_param(int, cbflood_n_burst, 3, "# bursts in flood, zero to disable");
63 torture_param(int, cbflood_n_per_burst, 20000,
64 "# callbacks per burst in flood");
65 torture_param(int, fqs_duration, 0,
66 "Duration of fqs bursts (us), 0 to disable");
67 torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
68 torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
69 torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
70 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
71 torture_param(bool, gp_normal, false,
72 "Use normal (non-expedited) GP wait primitives");
73 torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
74 torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
75 torture_param(int, n_barrier_cbs, 0,
76 "# of callbacks/kthreads for barrier testing");
77 torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
78 torture_param(int, nreaders, -1, "Number of RCU reader threads");
79 torture_param(int, object_debug, 0,
80 "Enable debug-object double call_rcu() testing");
81 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
82 torture_param(int, onoff_interval, 0,
83 "Time between CPU hotplugs (s), 0=disable");
84 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
85 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
86 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
87 torture_param(int, stall_cpu_holdoff, 10,
88 "Time to wait before starting stall (s).");
89 torture_param(int, stat_interval, 60,
90 "Number of seconds between stats printk()s");
91 torture_param(int, stutter, 5, "Number of seconds to run/halt test");
92 torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
93 torture_param(int, test_boost_duration, 4,
94 "Duration of each boost test, seconds.");
95 torture_param(int, test_boost_interval, 7,
96 "Interval between boost tests, seconds.");
97 torture_param(bool, test_no_idle_hz, true,
98 "Test support for tickless idle CPUs");
99 torture_param(bool, verbose, true,
100 "Enable verbose debugging printk()s");
101
102 static char *torture_type = "rcu";
103 module_param(torture_type, charp, 0444);
104 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, ...)");
105
106 static int nrealreaders;
107 static int ncbflooders;
108 static struct task_struct *writer_task;
109 static struct task_struct **fakewriter_tasks;
110 static struct task_struct **reader_tasks;
111 static struct task_struct *stats_task;
112 static struct task_struct **cbflood_task;
113 static struct task_struct *fqs_task;
114 static struct task_struct *boost_tasks[NR_CPUS];
115 static struct task_struct *stall_task;
116 static struct task_struct **barrier_cbs_tasks;
117 static struct task_struct *barrier_task;
118
119 #define RCU_TORTURE_PIPE_LEN 10
120
121 struct rcu_torture {
122 struct rcu_head rtort_rcu;
123 int rtort_pipe_count;
124 struct list_head rtort_free;
125 int rtort_mbtest;
126 };
127
128 static LIST_HEAD(rcu_torture_freelist);
129 static struct rcu_torture __rcu *rcu_torture_current;
130 static unsigned long rcu_torture_current_version;
131 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
132 static DEFINE_SPINLOCK(rcu_torture_lock);
133 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count);
134 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch);
135 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
136 static atomic_t n_rcu_torture_alloc;
137 static atomic_t n_rcu_torture_alloc_fail;
138 static atomic_t n_rcu_torture_free;
139 static atomic_t n_rcu_torture_mberror;
140 static atomic_t n_rcu_torture_error;
141 static long n_rcu_torture_barrier_error;
142 static long n_rcu_torture_boost_ktrerror;
143 static long n_rcu_torture_boost_rterror;
144 static long n_rcu_torture_boost_failure;
145 static long n_rcu_torture_boosts;
146 static long n_rcu_torture_timers;
147 static long n_barrier_attempts;
148 static long n_barrier_successes;
149 static atomic_long_t n_cbfloods;
150 static struct list_head rcu_torture_removed;
151
152 static int rcu_torture_writer_state;
153 #define RTWS_FIXED_DELAY 0
154 #define RTWS_DELAY 1
155 #define RTWS_REPLACE 2
156 #define RTWS_DEF_FREE 3
157 #define RTWS_EXP_SYNC 4
158 #define RTWS_COND_GET 5
159 #define RTWS_COND_SYNC 6
160 #define RTWS_SYNC 7
161 #define RTWS_STUTTER 8
162 #define RTWS_STOPPING 9
163 static const char * const rcu_torture_writer_state_names[] = {
164 "RTWS_FIXED_DELAY",
165 "RTWS_DELAY",
166 "RTWS_REPLACE",
167 "RTWS_DEF_FREE",
168 "RTWS_EXP_SYNC",
169 "RTWS_COND_GET",
170 "RTWS_COND_SYNC",
171 "RTWS_SYNC",
172 "RTWS_STUTTER",
173 "RTWS_STOPPING",
174 };
175
176 static const char *rcu_torture_writer_state_getname(void)
177 {
178 unsigned int i = READ_ONCE(rcu_torture_writer_state);
179
180 if (i >= ARRAY_SIZE(rcu_torture_writer_state_names))
181 return "???";
182 return rcu_torture_writer_state_names[i];
183 }
184
185 static int torture_runnable = IS_ENABLED(MODULE);
186 module_param(torture_runnable, int, 0444);
187 MODULE_PARM_DESC(torture_runnable, "Start rcutorture at boot");
188
189 #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
190 #define rcu_can_boost() 1
191 #else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
192 #define rcu_can_boost() 0
193 #endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
194
195 #ifdef CONFIG_RCU_TRACE
196 static u64 notrace rcu_trace_clock_local(void)
197 {
198 u64 ts = trace_clock_local();
199 unsigned long __maybe_unused ts_rem = do_div(ts, NSEC_PER_USEC);
200 return ts;
201 }
202 #else /* #ifdef CONFIG_RCU_TRACE */
203 static u64 notrace rcu_trace_clock_local(void)
204 {
205 return 0ULL;
206 }
207 #endif /* #else #ifdef CONFIG_RCU_TRACE */
208
209 static unsigned long boost_starttime; /* jiffies of next boost test start. */
210 static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
211 /* and boost task create/destroy. */
212 static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
213 static bool barrier_phase; /* Test phase. */
214 static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
215 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
216 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
217
218 /*
219 * Allocate an element from the rcu_tortures pool.
220 */
221 static struct rcu_torture *
222 rcu_torture_alloc(void)
223 {
224 struct list_head *p;
225
226 spin_lock_bh(&rcu_torture_lock);
227 if (list_empty(&rcu_torture_freelist)) {
228 atomic_inc(&n_rcu_torture_alloc_fail);
229 spin_unlock_bh(&rcu_torture_lock);
230 return NULL;
231 }
232 atomic_inc(&n_rcu_torture_alloc);
233 p = rcu_torture_freelist.next;
234 list_del_init(p);
235 spin_unlock_bh(&rcu_torture_lock);
236 return container_of(p, struct rcu_torture, rtort_free);
237 }
238
239 /*
240 * Free an element to the rcu_tortures pool.
241 */
242 static void
243 rcu_torture_free(struct rcu_torture *p)
244 {
245 atomic_inc(&n_rcu_torture_free);
246 spin_lock_bh(&rcu_torture_lock);
247 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
248 spin_unlock_bh(&rcu_torture_lock);
249 }
250
251 /*
252 * Operations vector for selecting different types of tests.
253 */
254
255 struct rcu_torture_ops {
256 int ttype;
257 void (*init)(void);
258 void (*cleanup)(void);
259 int (*readlock)(void);
260 void (*read_delay)(struct torture_random_state *rrsp);
261 void (*readunlock)(int idx);
262 unsigned long (*started)(void);
263 unsigned long (*completed)(void);
264 void (*deferred_free)(struct rcu_torture *p);
265 void (*sync)(void);
266 void (*exp_sync)(void);
267 unsigned long (*get_state)(void);
268 void (*cond_sync)(unsigned long oldstate);
269 call_rcu_func_t call;
270 void (*cb_barrier)(void);
271 void (*fqs)(void);
272 void (*stats)(void);
273 int irq_capable;
274 int can_boost;
275 const char *name;
276 };
277
278 static struct rcu_torture_ops *cur_ops;
279
280 /*
281 * Definitions for rcu torture testing.
282 */
283
284 static int rcu_torture_read_lock(void) __acquires(RCU)
285 {
286 rcu_read_lock();
287 return 0;
288 }
289
290 static void rcu_read_delay(struct torture_random_state *rrsp)
291 {
292 const unsigned long shortdelay_us = 200;
293 const unsigned long longdelay_ms = 50;
294
295 /* We want a short delay sometimes to make a reader delay the grace
296 * period, and we want a long delay occasionally to trigger
297 * force_quiescent_state. */
298
299 if (!(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms)))
300 mdelay(longdelay_ms);
301 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
302 udelay(shortdelay_us);
303 #ifdef CONFIG_PREEMPT
304 if (!preempt_count() &&
305 !(torture_random(rrsp) % (nrealreaders * 20000)))
306 preempt_schedule(); /* No QS if preempt_disable() in effect */
307 #endif
308 }
309
310 static void rcu_torture_read_unlock(int idx) __releases(RCU)
311 {
312 rcu_read_unlock();
313 }
314
315 /*
316 * Update callback in the pipe. This should be invoked after a grace period.
317 */
318 static bool
319 rcu_torture_pipe_update_one(struct rcu_torture *rp)
320 {
321 int i;
322
323 i = rp->rtort_pipe_count;
324 if (i > RCU_TORTURE_PIPE_LEN)
325 i = RCU_TORTURE_PIPE_LEN;
326 atomic_inc(&rcu_torture_wcount[i]);
327 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
328 rp->rtort_mbtest = 0;
329 return true;
330 }
331 return false;
332 }
333
334 /*
335 * Update all callbacks in the pipe. Suitable for synchronous grace-period
336 * primitives.
337 */
338 static void
339 rcu_torture_pipe_update(struct rcu_torture *old_rp)
340 {
341 struct rcu_torture *rp;
342 struct rcu_torture *rp1;
343
344 if (old_rp)
345 list_add(&old_rp->rtort_free, &rcu_torture_removed);
346 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
347 if (rcu_torture_pipe_update_one(rp)) {
348 list_del(&rp->rtort_free);
349 rcu_torture_free(rp);
350 }
351 }
352 }
353
354 static void
355 rcu_torture_cb(struct rcu_head *p)
356 {
357 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
358
359 if (torture_must_stop_irq()) {
360 /* Test is ending, just drop callbacks on the floor. */
361 /* The next initialization will pick up the pieces. */
362 return;
363 }
364 if (rcu_torture_pipe_update_one(rp))
365 rcu_torture_free(rp);
366 else
367 cur_ops->deferred_free(rp);
368 }
369
370 static unsigned long rcu_no_completed(void)
371 {
372 return 0;
373 }
374
375 static void rcu_torture_deferred_free(struct rcu_torture *p)
376 {
377 call_rcu(&p->rtort_rcu, rcu_torture_cb);
378 }
379
380 static void rcu_sync_torture_init(void)
381 {
382 INIT_LIST_HEAD(&rcu_torture_removed);
383 }
384
385 static struct rcu_torture_ops rcu_ops = {
386 .ttype = RCU_FLAVOR,
387 .init = rcu_sync_torture_init,
388 .readlock = rcu_torture_read_lock,
389 .read_delay = rcu_read_delay,
390 .readunlock = rcu_torture_read_unlock,
391 .started = rcu_batches_started,
392 .completed = rcu_batches_completed,
393 .deferred_free = rcu_torture_deferred_free,
394 .sync = synchronize_rcu,
395 .exp_sync = synchronize_rcu_expedited,
396 .get_state = get_state_synchronize_rcu,
397 .cond_sync = cond_synchronize_rcu,
398 .call = call_rcu,
399 .cb_barrier = rcu_barrier,
400 .fqs = rcu_force_quiescent_state,
401 .stats = NULL,
402 .irq_capable = 1,
403 .can_boost = rcu_can_boost(),
404 .name = "rcu"
405 };
406
407 /*
408 * Definitions for rcu_bh torture testing.
409 */
410
411 static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
412 {
413 rcu_read_lock_bh();
414 return 0;
415 }
416
417 static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
418 {
419 rcu_read_unlock_bh();
420 }
421
422 static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
423 {
424 call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
425 }
426
427 static struct rcu_torture_ops rcu_bh_ops = {
428 .ttype = RCU_BH_FLAVOR,
429 .init = rcu_sync_torture_init,
430 .readlock = rcu_bh_torture_read_lock,
431 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
432 .readunlock = rcu_bh_torture_read_unlock,
433 .started = rcu_batches_started_bh,
434 .completed = rcu_batches_completed_bh,
435 .deferred_free = rcu_bh_torture_deferred_free,
436 .sync = synchronize_rcu_bh,
437 .exp_sync = synchronize_rcu_bh_expedited,
438 .call = call_rcu_bh,
439 .cb_barrier = rcu_barrier_bh,
440 .fqs = rcu_bh_force_quiescent_state,
441 .stats = NULL,
442 .irq_capable = 1,
443 .name = "rcu_bh"
444 };
445
446 /*
447 * Don't even think about trying any of these in real life!!!
448 * The names includes "busted", and they really means it!
449 * The only purpose of these functions is to provide a buggy RCU
450 * implementation to make sure that rcutorture correctly emits
451 * buggy-RCU error messages.
452 */
453 static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
454 {
455 /* This is a deliberate bug for testing purposes only! */
456 rcu_torture_cb(&p->rtort_rcu);
457 }
458
459 static void synchronize_rcu_busted(void)
460 {
461 /* This is a deliberate bug for testing purposes only! */
462 }
463
464 static void
465 call_rcu_busted(struct rcu_head *head, rcu_callback_t func)
466 {
467 /* This is a deliberate bug for testing purposes only! */
468 func(head);
469 }
470
471 static struct rcu_torture_ops rcu_busted_ops = {
472 .ttype = INVALID_RCU_FLAVOR,
473 .init = rcu_sync_torture_init,
474 .readlock = rcu_torture_read_lock,
475 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
476 .readunlock = rcu_torture_read_unlock,
477 .started = rcu_no_completed,
478 .completed = rcu_no_completed,
479 .deferred_free = rcu_busted_torture_deferred_free,
480 .sync = synchronize_rcu_busted,
481 .exp_sync = synchronize_rcu_busted,
482 .call = call_rcu_busted,
483 .cb_barrier = NULL,
484 .fqs = NULL,
485 .stats = NULL,
486 .irq_capable = 1,
487 .name = "rcu_busted"
488 };
489
490 /*
491 * Definitions for srcu torture testing.
492 */
493
494 DEFINE_STATIC_SRCU(srcu_ctl);
495 static struct srcu_struct srcu_ctld;
496 static struct srcu_struct *srcu_ctlp = &srcu_ctl;
497
498 static int srcu_torture_read_lock(void) __acquires(srcu_ctlp)
499 {
500 return srcu_read_lock(srcu_ctlp);
501 }
502
503 static void srcu_read_delay(struct torture_random_state *rrsp)
504 {
505 long delay;
506 const long uspertick = 1000000 / HZ;
507 const long longdelay = 10;
508
509 /* We want there to be long-running readers, but not all the time. */
510
511 delay = torture_random(rrsp) %
512 (nrealreaders * 2 * longdelay * uspertick);
513 if (!delay)
514 schedule_timeout_interruptible(longdelay);
515 else
516 rcu_read_delay(rrsp);
517 }
518
519 static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp)
520 {
521 srcu_read_unlock(srcu_ctlp, idx);
522 }
523
524 static unsigned long srcu_torture_completed(void)
525 {
526 return srcu_batches_completed(srcu_ctlp);
527 }
528
529 static void srcu_torture_deferred_free(struct rcu_torture *rp)
530 {
531 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
532 }
533
534 static void srcu_torture_synchronize(void)
535 {
536 synchronize_srcu(srcu_ctlp);
537 }
538
539 static void srcu_torture_call(struct rcu_head *head,
540 rcu_callback_t func)
541 {
542 call_srcu(srcu_ctlp, head, func);
543 }
544
545 static void srcu_torture_barrier(void)
546 {
547 srcu_barrier(srcu_ctlp);
548 }
549
550 static void srcu_torture_stats(void)
551 {
552 int cpu;
553 int idx = srcu_ctlp->completed & 0x1;
554
555 pr_alert("%s%s per-CPU(idx=%d):",
556 torture_type, TORTURE_FLAG, idx);
557 for_each_possible_cpu(cpu) {
558 long c0, c1;
559
560 c0 = (long)per_cpu_ptr(srcu_ctlp->per_cpu_ref, cpu)->c[!idx];
561 c1 = (long)per_cpu_ptr(srcu_ctlp->per_cpu_ref, cpu)->c[idx];
562 pr_cont(" %d(%ld,%ld)", cpu, c0, c1);
563 }
564 pr_cont("\n");
565 }
566
567 static void srcu_torture_synchronize_expedited(void)
568 {
569 synchronize_srcu_expedited(srcu_ctlp);
570 }
571
572 static struct rcu_torture_ops srcu_ops = {
573 .ttype = SRCU_FLAVOR,
574 .init = rcu_sync_torture_init,
575 .readlock = srcu_torture_read_lock,
576 .read_delay = srcu_read_delay,
577 .readunlock = srcu_torture_read_unlock,
578 .started = NULL,
579 .completed = srcu_torture_completed,
580 .deferred_free = srcu_torture_deferred_free,
581 .sync = srcu_torture_synchronize,
582 .exp_sync = srcu_torture_synchronize_expedited,
583 .call = srcu_torture_call,
584 .cb_barrier = srcu_torture_barrier,
585 .stats = srcu_torture_stats,
586 .name = "srcu"
587 };
588
589 static void srcu_torture_init(void)
590 {
591 rcu_sync_torture_init();
592 WARN_ON(init_srcu_struct(&srcu_ctld));
593 srcu_ctlp = &srcu_ctld;
594 }
595
596 static void srcu_torture_cleanup(void)
597 {
598 cleanup_srcu_struct(&srcu_ctld);
599 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
600 }
601
602 /* As above, but dynamically allocated. */
603 static struct rcu_torture_ops srcud_ops = {
604 .ttype = SRCU_FLAVOR,
605 .init = srcu_torture_init,
606 .cleanup = srcu_torture_cleanup,
607 .readlock = srcu_torture_read_lock,
608 .read_delay = srcu_read_delay,
609 .readunlock = srcu_torture_read_unlock,
610 .started = NULL,
611 .completed = srcu_torture_completed,
612 .deferred_free = srcu_torture_deferred_free,
613 .sync = srcu_torture_synchronize,
614 .exp_sync = srcu_torture_synchronize_expedited,
615 .call = srcu_torture_call,
616 .cb_barrier = srcu_torture_barrier,
617 .stats = srcu_torture_stats,
618 .name = "srcud"
619 };
620
621 /*
622 * Definitions for sched torture testing.
623 */
624
625 static int sched_torture_read_lock(void)
626 {
627 preempt_disable();
628 return 0;
629 }
630
631 static void sched_torture_read_unlock(int idx)
632 {
633 preempt_enable();
634 }
635
636 static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
637 {
638 call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
639 }
640
641 static struct rcu_torture_ops sched_ops = {
642 .ttype = RCU_SCHED_FLAVOR,
643 .init = rcu_sync_torture_init,
644 .readlock = sched_torture_read_lock,
645 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
646 .readunlock = sched_torture_read_unlock,
647 .started = rcu_batches_started_sched,
648 .completed = rcu_batches_completed_sched,
649 .deferred_free = rcu_sched_torture_deferred_free,
650 .sync = synchronize_sched,
651 .exp_sync = synchronize_sched_expedited,
652 .get_state = get_state_synchronize_sched,
653 .cond_sync = cond_synchronize_sched,
654 .call = call_rcu_sched,
655 .cb_barrier = rcu_barrier_sched,
656 .fqs = rcu_sched_force_quiescent_state,
657 .stats = NULL,
658 .irq_capable = 1,
659 .name = "sched"
660 };
661
662 #ifdef CONFIG_TASKS_RCU
663
664 /*
665 * Definitions for RCU-tasks torture testing.
666 */
667
668 static int tasks_torture_read_lock(void)
669 {
670 return 0;
671 }
672
673 static void tasks_torture_read_unlock(int idx)
674 {
675 }
676
677 static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
678 {
679 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
680 }
681
682 static struct rcu_torture_ops tasks_ops = {
683 .ttype = RCU_TASKS_FLAVOR,
684 .init = rcu_sync_torture_init,
685 .readlock = tasks_torture_read_lock,
686 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
687 .readunlock = tasks_torture_read_unlock,
688 .started = rcu_no_completed,
689 .completed = rcu_no_completed,
690 .deferred_free = rcu_tasks_torture_deferred_free,
691 .sync = synchronize_rcu_tasks,
692 .exp_sync = synchronize_rcu_tasks,
693 .call = call_rcu_tasks,
694 .cb_barrier = rcu_barrier_tasks,
695 .fqs = NULL,
696 .stats = NULL,
697 .irq_capable = 1,
698 .name = "tasks"
699 };
700
701 #define RCUTORTURE_TASKS_OPS &tasks_ops,
702
703 static bool __maybe_unused torturing_tasks(void)
704 {
705 return cur_ops == &tasks_ops;
706 }
707
708 #else /* #ifdef CONFIG_TASKS_RCU */
709
710 #define RCUTORTURE_TASKS_OPS
711
712 static bool __maybe_unused torturing_tasks(void)
713 {
714 return false;
715 }
716
717 #endif /* #else #ifdef CONFIG_TASKS_RCU */
718
719 /*
720 * RCU torture priority-boost testing. Runs one real-time thread per
721 * CPU for moderate bursts, repeatedly registering RCU callbacks and
722 * spinning waiting for them to be invoked. If a given callback takes
723 * too long to be invoked, we assume that priority inversion has occurred.
724 */
725
726 struct rcu_boost_inflight {
727 struct rcu_head rcu;
728 int inflight;
729 };
730
731 static void rcu_torture_boost_cb(struct rcu_head *head)
732 {
733 struct rcu_boost_inflight *rbip =
734 container_of(head, struct rcu_boost_inflight, rcu);
735
736 /* Ensure RCU-core accesses precede clearing ->inflight */
737 smp_store_release(&rbip->inflight, 0);
738 }
739
740 static int rcu_torture_boost(void *arg)
741 {
742 unsigned long call_rcu_time;
743 unsigned long endtime;
744 unsigned long oldstarttime;
745 struct rcu_boost_inflight rbi = { .inflight = 0 };
746 struct sched_param sp;
747
748 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
749
750 /* Set real-time priority. */
751 sp.sched_priority = 1;
752 if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
753 VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!");
754 n_rcu_torture_boost_rterror++;
755 }
756
757 init_rcu_head_on_stack(&rbi.rcu);
758 /* Each pass through the following loop does one boost-test cycle. */
759 do {
760 /* Wait for the next test interval. */
761 oldstarttime = boost_starttime;
762 while (ULONG_CMP_LT(jiffies, oldstarttime)) {
763 schedule_timeout_interruptible(oldstarttime - jiffies);
764 stutter_wait("rcu_torture_boost");
765 if (torture_must_stop())
766 goto checkwait;
767 }
768
769 /* Do one boost-test interval. */
770 endtime = oldstarttime + test_boost_duration * HZ;
771 call_rcu_time = jiffies;
772 while (ULONG_CMP_LT(jiffies, endtime)) {
773 /* If we don't have a callback in flight, post one. */
774 if (!smp_load_acquire(&rbi.inflight)) {
775 /* RCU core before ->inflight = 1. */
776 smp_store_release(&rbi.inflight, 1);
777 call_rcu(&rbi.rcu, rcu_torture_boost_cb);
778 if (jiffies - call_rcu_time >
779 test_boost_duration * HZ - HZ / 2) {
780 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
781 n_rcu_torture_boost_failure++;
782 }
783 call_rcu_time = jiffies;
784 }
785 stutter_wait("rcu_torture_boost");
786 if (torture_must_stop())
787 goto checkwait;
788 }
789
790 /*
791 * Set the start time of the next test interval.
792 * Yes, this is vulnerable to long delays, but such
793 * delays simply cause a false negative for the next
794 * interval. Besides, we are running at RT priority,
795 * so delays should be relatively rare.
796 */
797 while (oldstarttime == boost_starttime &&
798 !kthread_should_stop()) {
799 if (mutex_trylock(&boost_mutex)) {
800 boost_starttime = jiffies +
801 test_boost_interval * HZ;
802 n_rcu_torture_boosts++;
803 mutex_unlock(&boost_mutex);
804 break;
805 }
806 schedule_timeout_uninterruptible(1);
807 }
808
809 /* Go do the stutter. */
810 checkwait: stutter_wait("rcu_torture_boost");
811 } while (!torture_must_stop());
812
813 /* Clean up and exit. */
814 while (!kthread_should_stop() || smp_load_acquire(&rbi.inflight)) {
815 torture_shutdown_absorb("rcu_torture_boost");
816 schedule_timeout_uninterruptible(1);
817 }
818 destroy_rcu_head_on_stack(&rbi.rcu);
819 torture_kthread_stopping("rcu_torture_boost");
820 return 0;
821 }
822
823 static void rcu_torture_cbflood_cb(struct rcu_head *rhp)
824 {
825 }
826
827 /*
828 * RCU torture callback-flood kthread. Repeatedly induces bursts of calls
829 * to call_rcu() or analogous, increasing the probability of occurrence
830 * of callback-overflow corner cases.
831 */
832 static int
833 rcu_torture_cbflood(void *arg)
834 {
835 int err = 1;
836 int i;
837 int j;
838 struct rcu_head *rhp;
839
840 if (cbflood_n_per_burst > 0 &&
841 cbflood_inter_holdoff > 0 &&
842 cbflood_intra_holdoff > 0 &&
843 cur_ops->call &&
844 cur_ops->cb_barrier) {
845 rhp = vmalloc(sizeof(*rhp) *
846 cbflood_n_burst * cbflood_n_per_burst);
847 err = !rhp;
848 }
849 if (err) {
850 VERBOSE_TOROUT_STRING("rcu_torture_cbflood disabled: Bad args or OOM");
851 goto wait_for_stop;
852 }
853 VERBOSE_TOROUT_STRING("rcu_torture_cbflood task started");
854 do {
855 schedule_timeout_interruptible(cbflood_inter_holdoff);
856 atomic_long_inc(&n_cbfloods);
857 WARN_ON(signal_pending(current));
858 for (i = 0; i < cbflood_n_burst; i++) {
859 for (j = 0; j < cbflood_n_per_burst; j++) {
860 cur_ops->call(&rhp[i * cbflood_n_per_burst + j],
861 rcu_torture_cbflood_cb);
862 }
863 schedule_timeout_interruptible(cbflood_intra_holdoff);
864 WARN_ON(signal_pending(current));
865 }
866 cur_ops->cb_barrier();
867 stutter_wait("rcu_torture_cbflood");
868 } while (!torture_must_stop());
869 vfree(rhp);
870 wait_for_stop:
871 torture_kthread_stopping("rcu_torture_cbflood");
872 return 0;
873 }
874
875 /*
876 * RCU torture force-quiescent-state kthread. Repeatedly induces
877 * bursts of calls to force_quiescent_state(), increasing the probability
878 * of occurrence of some important types of race conditions.
879 */
880 static int
881 rcu_torture_fqs(void *arg)
882 {
883 unsigned long fqs_resume_time;
884 int fqs_burst_remaining;
885
886 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
887 do {
888 fqs_resume_time = jiffies + fqs_stutter * HZ;
889 while (ULONG_CMP_LT(jiffies, fqs_resume_time) &&
890 !kthread_should_stop()) {
891 schedule_timeout_interruptible(1);
892 }
893 fqs_burst_remaining = fqs_duration;
894 while (fqs_burst_remaining > 0 &&
895 !kthread_should_stop()) {
896 cur_ops->fqs();
897 udelay(fqs_holdoff);
898 fqs_burst_remaining -= fqs_holdoff;
899 }
900 stutter_wait("rcu_torture_fqs");
901 } while (!torture_must_stop());
902 torture_kthread_stopping("rcu_torture_fqs");
903 return 0;
904 }
905
906 /*
907 * RCU torture writer kthread. Repeatedly substitutes a new structure
908 * for that pointed to by rcu_torture_current, freeing the old structure
909 * after a series of grace periods (the "pipeline").
910 */
911 static int
912 rcu_torture_writer(void *arg)
913 {
914 bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
915 int expediting = 0;
916 unsigned long gp_snap;
917 bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal;
918 bool gp_sync1 = gp_sync;
919 int i;
920 struct rcu_torture *rp;
921 struct rcu_torture *old_rp;
922 static DEFINE_TORTURE_RANDOM(rand);
923 int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC,
924 RTWS_COND_GET, RTWS_SYNC };
925 int nsynctypes = 0;
926
927 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
928 if (!can_expedite) {
929 pr_alert("%s" TORTURE_FLAG
930 " GP expediting controlled from boot/sysfs for %s,\n",
931 torture_type, cur_ops->name);
932 pr_alert("%s" TORTURE_FLAG
933 " Disabled dynamic grace-period expediting.\n",
934 torture_type);
935 }
936
937 /* Initialize synctype[] array. If none set, take default. */
938 if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync1)
939 gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true;
940 if (gp_cond1 && cur_ops->get_state && cur_ops->cond_sync)
941 synctype[nsynctypes++] = RTWS_COND_GET;
942 else if (gp_cond && (!cur_ops->get_state || !cur_ops->cond_sync))
943 pr_alert("rcu_torture_writer: gp_cond without primitives.\n");
944 if (gp_exp1 && cur_ops->exp_sync)
945 synctype[nsynctypes++] = RTWS_EXP_SYNC;
946 else if (gp_exp && !cur_ops->exp_sync)
947 pr_alert("rcu_torture_writer: gp_exp without primitives.\n");
948 if (gp_normal1 && cur_ops->deferred_free)
949 synctype[nsynctypes++] = RTWS_DEF_FREE;
950 else if (gp_normal && !cur_ops->deferred_free)
951 pr_alert("rcu_torture_writer: gp_normal without primitives.\n");
952 if (gp_sync1 && cur_ops->sync)
953 synctype[nsynctypes++] = RTWS_SYNC;
954 else if (gp_sync && !cur_ops->sync)
955 pr_alert("rcu_torture_writer: gp_sync without primitives.\n");
956 if (WARN_ONCE(nsynctypes == 0,
957 "rcu_torture_writer: No update-side primitives.\n")) {
958 /*
959 * No updates primitives, so don't try updating.
960 * The resulting test won't be testing much, hence the
961 * above WARN_ONCE().
962 */
963 rcu_torture_writer_state = RTWS_STOPPING;
964 torture_kthread_stopping("rcu_torture_writer");
965 }
966
967 do {
968 rcu_torture_writer_state = RTWS_FIXED_DELAY;
969 schedule_timeout_uninterruptible(1);
970 rp = rcu_torture_alloc();
971 if (rp == NULL)
972 continue;
973 rp->rtort_pipe_count = 0;
974 rcu_torture_writer_state = RTWS_DELAY;
975 udelay(torture_random(&rand) & 0x3ff);
976 rcu_torture_writer_state = RTWS_REPLACE;
977 old_rp = rcu_dereference_check(rcu_torture_current,
978 current == writer_task);
979 rp->rtort_mbtest = 1;
980 rcu_assign_pointer(rcu_torture_current, rp);
981 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
982 if (old_rp) {
983 i = old_rp->rtort_pipe_count;
984 if (i > RCU_TORTURE_PIPE_LEN)
985 i = RCU_TORTURE_PIPE_LEN;
986 atomic_inc(&rcu_torture_wcount[i]);
987 old_rp->rtort_pipe_count++;
988 switch (synctype[torture_random(&rand) % nsynctypes]) {
989 case RTWS_DEF_FREE:
990 rcu_torture_writer_state = RTWS_DEF_FREE;
991 cur_ops->deferred_free(old_rp);
992 break;
993 case RTWS_EXP_SYNC:
994 rcu_torture_writer_state = RTWS_EXP_SYNC;
995 cur_ops->exp_sync();
996 rcu_torture_pipe_update(old_rp);
997 break;
998 case RTWS_COND_GET:
999 rcu_torture_writer_state = RTWS_COND_GET;
1000 gp_snap = cur_ops->get_state();
1001 i = torture_random(&rand) % 16;
1002 if (i != 0)
1003 schedule_timeout_interruptible(i);
1004 udelay(torture_random(&rand) % 1000);
1005 rcu_torture_writer_state = RTWS_COND_SYNC;
1006 cur_ops->cond_sync(gp_snap);
1007 rcu_torture_pipe_update(old_rp);
1008 break;
1009 case RTWS_SYNC:
1010 rcu_torture_writer_state = RTWS_SYNC;
1011 cur_ops->sync();
1012 rcu_torture_pipe_update(old_rp);
1013 break;
1014 default:
1015 WARN_ON_ONCE(1);
1016 break;
1017 }
1018 }
1019 rcutorture_record_progress(++rcu_torture_current_version);
1020 /* Cycle through nesting levels of rcu_expedite_gp() calls. */
1021 if (can_expedite &&
1022 !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
1023 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
1024 if (expediting >= 0)
1025 rcu_expedite_gp();
1026 else
1027 rcu_unexpedite_gp();
1028 if (++expediting > 3)
1029 expediting = -expediting;
1030 }
1031 rcu_torture_writer_state = RTWS_STUTTER;
1032 stutter_wait("rcu_torture_writer");
1033 } while (!torture_must_stop());
1034 /* Reset expediting back to unexpedited. */
1035 if (expediting > 0)
1036 expediting = -expediting;
1037 while (can_expedite && expediting++ < 0)
1038 rcu_unexpedite_gp();
1039 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
1040 rcu_torture_writer_state = RTWS_STOPPING;
1041 torture_kthread_stopping("rcu_torture_writer");
1042 return 0;
1043 }
1044
1045 /*
1046 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
1047 * delay between calls.
1048 */
1049 static int
1050 rcu_torture_fakewriter(void *arg)
1051 {
1052 DEFINE_TORTURE_RANDOM(rand);
1053
1054 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1055 set_user_nice(current, MAX_NICE);
1056
1057 do {
1058 schedule_timeout_uninterruptible(1 + torture_random(&rand)%10);
1059 udelay(torture_random(&rand) & 0x3ff);
1060 if (cur_ops->cb_barrier != NULL &&
1061 torture_random(&rand) % (nfakewriters * 8) == 0) {
1062 cur_ops->cb_barrier();
1063 } else if (gp_normal == gp_exp) {
1064 if (torture_random(&rand) & 0x80)
1065 cur_ops->sync();
1066 else
1067 cur_ops->exp_sync();
1068 } else if (gp_normal) {
1069 cur_ops->sync();
1070 } else {
1071 cur_ops->exp_sync();
1072 }
1073 stutter_wait("rcu_torture_fakewriter");
1074 } while (!torture_must_stop());
1075
1076 torture_kthread_stopping("rcu_torture_fakewriter");
1077 return 0;
1078 }
1079
1080 /*
1081 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
1082 * incrementing the corresponding element of the pipeline array. The
1083 * counter in the element should never be greater than 1, otherwise, the
1084 * RCU implementation is broken.
1085 */
1086 static void rcu_torture_timer(unsigned long unused)
1087 {
1088 int idx;
1089 unsigned long started;
1090 unsigned long completed;
1091 static DEFINE_TORTURE_RANDOM(rand);
1092 static DEFINE_SPINLOCK(rand_lock);
1093 struct rcu_torture *p;
1094 int pipe_count;
1095 unsigned long long ts;
1096
1097 idx = cur_ops->readlock();
1098 if (cur_ops->started)
1099 started = cur_ops->started();
1100 else
1101 started = cur_ops->completed();
1102 ts = rcu_trace_clock_local();
1103 p = rcu_dereference_check(rcu_torture_current,
1104 rcu_read_lock_bh_held() ||
1105 rcu_read_lock_sched_held() ||
1106 srcu_read_lock_held(srcu_ctlp) ||
1107 torturing_tasks());
1108 if (p == NULL) {
1109 /* Leave because rcu_torture_writer is not yet underway */
1110 cur_ops->readunlock(idx);
1111 return;
1112 }
1113 if (p->rtort_mbtest == 0)
1114 atomic_inc(&n_rcu_torture_mberror);
1115 spin_lock(&rand_lock);
1116 cur_ops->read_delay(&rand);
1117 n_rcu_torture_timers++;
1118 spin_unlock(&rand_lock);
1119 preempt_disable();
1120 pipe_count = p->rtort_pipe_count;
1121 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1122 /* Should not happen, but... */
1123 pipe_count = RCU_TORTURE_PIPE_LEN;
1124 }
1125 completed = cur_ops->completed();
1126 if (pipe_count > 1) {
1127 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, ts,
1128 started, completed);
1129 rcu_ftrace_dump(DUMP_ALL);
1130 }
1131 __this_cpu_inc(rcu_torture_count[pipe_count]);
1132 completed = completed - started;
1133 if (cur_ops->started)
1134 completed++;
1135 if (completed > RCU_TORTURE_PIPE_LEN) {
1136 /* Should not happen, but... */
1137 completed = RCU_TORTURE_PIPE_LEN;
1138 }
1139 __this_cpu_inc(rcu_torture_batch[completed]);
1140 preempt_enable();
1141 cur_ops->readunlock(idx);
1142 }
1143
1144 /*
1145 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
1146 * incrementing the corresponding element of the pipeline array. The
1147 * counter in the element should never be greater than 1, otherwise, the
1148 * RCU implementation is broken.
1149 */
1150 static int
1151 rcu_torture_reader(void *arg)
1152 {
1153 unsigned long started;
1154 unsigned long completed;
1155 int idx;
1156 DEFINE_TORTURE_RANDOM(rand);
1157 struct rcu_torture *p;
1158 int pipe_count;
1159 struct timer_list t;
1160 unsigned long long ts;
1161
1162 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
1163 set_user_nice(current, MAX_NICE);
1164 if (irqreader && cur_ops->irq_capable)
1165 setup_timer_on_stack(&t, rcu_torture_timer, 0);
1166
1167 do {
1168 if (irqreader && cur_ops->irq_capable) {
1169 if (!timer_pending(&t))
1170 mod_timer(&t, jiffies + 1);
1171 }
1172 idx = cur_ops->readlock();
1173 if (cur_ops->started)
1174 started = cur_ops->started();
1175 else
1176 started = cur_ops->completed();
1177 ts = rcu_trace_clock_local();
1178 p = rcu_dereference_check(rcu_torture_current,
1179 rcu_read_lock_bh_held() ||
1180 rcu_read_lock_sched_held() ||
1181 srcu_read_lock_held(srcu_ctlp) ||
1182 torturing_tasks());
1183 if (p == NULL) {
1184 /* Wait for rcu_torture_writer to get underway */
1185 cur_ops->readunlock(idx);
1186 schedule_timeout_interruptible(HZ);
1187 continue;
1188 }
1189 if (p->rtort_mbtest == 0)
1190 atomic_inc(&n_rcu_torture_mberror);
1191 cur_ops->read_delay(&rand);
1192 preempt_disable();
1193 pipe_count = p->rtort_pipe_count;
1194 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1195 /* Should not happen, but... */
1196 pipe_count = RCU_TORTURE_PIPE_LEN;
1197 }
1198 completed = cur_ops->completed();
1199 if (pipe_count > 1) {
1200 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
1201 ts, started, completed);
1202 rcu_ftrace_dump(DUMP_ALL);
1203 }
1204 __this_cpu_inc(rcu_torture_count[pipe_count]);
1205 completed = completed - started;
1206 if (cur_ops->started)
1207 completed++;
1208 if (completed > RCU_TORTURE_PIPE_LEN) {
1209 /* Should not happen, but... */
1210 completed = RCU_TORTURE_PIPE_LEN;
1211 }
1212 __this_cpu_inc(rcu_torture_batch[completed]);
1213 preempt_enable();
1214 cur_ops->readunlock(idx);
1215 stutter_wait("rcu_torture_reader");
1216 } while (!torture_must_stop());
1217 if (irqreader && cur_ops->irq_capable) {
1218 del_timer_sync(&t);
1219 destroy_timer_on_stack(&t);
1220 }
1221 torture_kthread_stopping("rcu_torture_reader");
1222 return 0;
1223 }
1224
1225 /*
1226 * Print torture statistics. Caller must ensure that there is only
1227 * one call to this function at a given time!!! This is normally
1228 * accomplished by relying on the module system to only have one copy
1229 * of the module loaded, and then by giving the rcu_torture_stats
1230 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1231 * thread is not running).
1232 */
1233 static void
1234 rcu_torture_stats_print(void)
1235 {
1236 int cpu;
1237 int i;
1238 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1239 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1240 static unsigned long rtcv_snap = ULONG_MAX;
1241
1242 for_each_possible_cpu(cpu) {
1243 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1244 pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
1245 batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
1246 }
1247 }
1248 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
1249 if (pipesummary[i] != 0)
1250 break;
1251 }
1252
1253 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1254 pr_cont("rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
1255 rcu_torture_current,
1256 rcu_torture_current_version,
1257 list_empty(&rcu_torture_freelist),
1258 atomic_read(&n_rcu_torture_alloc),
1259 atomic_read(&n_rcu_torture_alloc_fail),
1260 atomic_read(&n_rcu_torture_free));
1261 pr_cont("rtmbe: %d rtbke: %ld rtbre: %ld ",
1262 atomic_read(&n_rcu_torture_mberror),
1263 n_rcu_torture_boost_ktrerror,
1264 n_rcu_torture_boost_rterror);
1265 pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
1266 n_rcu_torture_boost_failure,
1267 n_rcu_torture_boosts,
1268 n_rcu_torture_timers);
1269 torture_onoff_stats();
1270 pr_cont("barrier: %ld/%ld:%ld ",
1271 n_barrier_successes,
1272 n_barrier_attempts,
1273 n_rcu_torture_barrier_error);
1274 pr_cont("cbflood: %ld\n", atomic_long_read(&n_cbfloods));
1275
1276 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1277 if (atomic_read(&n_rcu_torture_mberror) != 0 ||
1278 n_rcu_torture_barrier_error != 0 ||
1279 n_rcu_torture_boost_ktrerror != 0 ||
1280 n_rcu_torture_boost_rterror != 0 ||
1281 n_rcu_torture_boost_failure != 0 ||
1282 i > 1) {
1283 pr_cont("%s", "!!! ");
1284 atomic_inc(&n_rcu_torture_error);
1285 WARN_ON_ONCE(1);
1286 }
1287 pr_cont("Reader Pipe: ");
1288 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1289 pr_cont(" %ld", pipesummary[i]);
1290 pr_cont("\n");
1291
1292 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1293 pr_cont("Reader Batch: ");
1294 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1295 pr_cont(" %ld", batchsummary[i]);
1296 pr_cont("\n");
1297
1298 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1299 pr_cont("Free-Block Circulation: ");
1300 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1301 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
1302 }
1303 pr_cont("\n");
1304
1305 if (cur_ops->stats)
1306 cur_ops->stats();
1307 if (rtcv_snap == rcu_torture_current_version &&
1308 rcu_torture_current != NULL) {
1309 int __maybe_unused flags;
1310 unsigned long __maybe_unused gpnum;
1311 unsigned long __maybe_unused completed;
1312
1313 rcutorture_get_gp_data(cur_ops->ttype,
1314 &flags, &gpnum, &completed);
1315 pr_alert("??? Writer stall state %s(%d) g%lu c%lu f%#x\n",
1316 rcu_torture_writer_state_getname(),
1317 rcu_torture_writer_state,
1318 gpnum, completed, flags);
1319 show_rcu_gp_kthreads();
1320 rcu_ftrace_dump(DUMP_ALL);
1321 }
1322 rtcv_snap = rcu_torture_current_version;
1323 }
1324
1325 /*
1326 * Periodically prints torture statistics, if periodic statistics printing
1327 * was specified via the stat_interval module parameter.
1328 */
1329 static int
1330 rcu_torture_stats(void *arg)
1331 {
1332 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1333 do {
1334 schedule_timeout_interruptible(stat_interval * HZ);
1335 rcu_torture_stats_print();
1336 torture_shutdown_absorb("rcu_torture_stats");
1337 } while (!torture_must_stop());
1338 torture_kthread_stopping("rcu_torture_stats");
1339 return 0;
1340 }
1341
1342 static inline void
1343 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1344 {
1345 pr_alert("%s" TORTURE_FLAG
1346 "--- %s: nreaders=%d nfakewriters=%d "
1347 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1348 "shuffle_interval=%d stutter=%d irqreader=%d "
1349 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1350 "test_boost=%d/%d test_boost_interval=%d "
1351 "test_boost_duration=%d shutdown_secs=%d "
1352 "stall_cpu=%d stall_cpu_holdoff=%d "
1353 "n_barrier_cbs=%d "
1354 "onoff_interval=%d onoff_holdoff=%d\n",
1355 torture_type, tag, nrealreaders, nfakewriters,
1356 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1357 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1358 test_boost, cur_ops->can_boost,
1359 test_boost_interval, test_boost_duration, shutdown_secs,
1360 stall_cpu, stall_cpu_holdoff,
1361 n_barrier_cbs,
1362 onoff_interval, onoff_holdoff);
1363 }
1364
1365 static void rcutorture_booster_cleanup(int cpu)
1366 {
1367 struct task_struct *t;
1368
1369 if (boost_tasks[cpu] == NULL)
1370 return;
1371 mutex_lock(&boost_mutex);
1372 t = boost_tasks[cpu];
1373 boost_tasks[cpu] = NULL;
1374 mutex_unlock(&boost_mutex);
1375
1376 /* This must be outside of the mutex, otherwise deadlock! */
1377 torture_stop_kthread(rcu_torture_boost, t);
1378 }
1379
1380 static int rcutorture_booster_init(int cpu)
1381 {
1382 int retval;
1383
1384 if (boost_tasks[cpu] != NULL)
1385 return 0; /* Already created, nothing more to do. */
1386
1387 /* Don't allow time recalculation while creating a new task. */
1388 mutex_lock(&boost_mutex);
1389 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
1390 boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
1391 cpu_to_node(cpu),
1392 "rcu_torture_boost");
1393 if (IS_ERR(boost_tasks[cpu])) {
1394 retval = PTR_ERR(boost_tasks[cpu]);
1395 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
1396 n_rcu_torture_boost_ktrerror++;
1397 boost_tasks[cpu] = NULL;
1398 mutex_unlock(&boost_mutex);
1399 return retval;
1400 }
1401 kthread_bind(boost_tasks[cpu], cpu);
1402 wake_up_process(boost_tasks[cpu]);
1403 mutex_unlock(&boost_mutex);
1404 return 0;
1405 }
1406
1407 /*
1408 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
1409 * induces a CPU stall for the time specified by stall_cpu.
1410 */
1411 static int rcu_torture_stall(void *args)
1412 {
1413 unsigned long stop_at;
1414
1415 VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
1416 if (stall_cpu_holdoff > 0) {
1417 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
1418 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
1419 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
1420 }
1421 if (!kthread_should_stop()) {
1422 stop_at = get_seconds() + stall_cpu;
1423 /* RCU CPU stall is expected behavior in following code. */
1424 pr_alert("rcu_torture_stall start.\n");
1425 rcu_read_lock();
1426 preempt_disable();
1427 while (ULONG_CMP_LT(get_seconds(), stop_at))
1428 continue; /* Induce RCU CPU stall warning. */
1429 preempt_enable();
1430 rcu_read_unlock();
1431 pr_alert("rcu_torture_stall end.\n");
1432 }
1433 torture_shutdown_absorb("rcu_torture_stall");
1434 while (!kthread_should_stop())
1435 schedule_timeout_interruptible(10 * HZ);
1436 return 0;
1437 }
1438
1439 /* Spawn CPU-stall kthread, if stall_cpu specified. */
1440 static int __init rcu_torture_stall_init(void)
1441 {
1442 if (stall_cpu <= 0)
1443 return 0;
1444 return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
1445 }
1446
1447 /* Callback function for RCU barrier testing. */
1448 static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
1449 {
1450 atomic_inc(&barrier_cbs_invoked);
1451 }
1452
1453 /* kthread function to register callbacks used to test RCU barriers. */
1454 static int rcu_torture_barrier_cbs(void *arg)
1455 {
1456 long myid = (long)arg;
1457 bool lastphase = 0;
1458 bool newphase;
1459 struct rcu_head rcu;
1460
1461 init_rcu_head_on_stack(&rcu);
1462 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
1463 set_user_nice(current, MAX_NICE);
1464 do {
1465 wait_event(barrier_cbs_wq[myid],
1466 (newphase =
1467 smp_load_acquire(&barrier_phase)) != lastphase ||
1468 torture_must_stop());
1469 lastphase = newphase;
1470 if (torture_must_stop())
1471 break;
1472 /*
1473 * The above smp_load_acquire() ensures barrier_phase load
1474 * is ordered before the following ->call().
1475 */
1476 local_irq_disable(); /* Just to test no-irq call_rcu(). */
1477 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
1478 local_irq_enable();
1479 if (atomic_dec_and_test(&barrier_cbs_count))
1480 wake_up(&barrier_wq);
1481 } while (!torture_must_stop());
1482 if (cur_ops->cb_barrier != NULL)
1483 cur_ops->cb_barrier();
1484 destroy_rcu_head_on_stack(&rcu);
1485 torture_kthread_stopping("rcu_torture_barrier_cbs");
1486 return 0;
1487 }
1488
1489 /* kthread function to drive and coordinate RCU barrier testing. */
1490 static int rcu_torture_barrier(void *arg)
1491 {
1492 int i;
1493
1494 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
1495 do {
1496 atomic_set(&barrier_cbs_invoked, 0);
1497 atomic_set(&barrier_cbs_count, n_barrier_cbs);
1498 /* Ensure barrier_phase ordered after prior assignments. */
1499 smp_store_release(&barrier_phase, !barrier_phase);
1500 for (i = 0; i < n_barrier_cbs; i++)
1501 wake_up(&barrier_cbs_wq[i]);
1502 wait_event(barrier_wq,
1503 atomic_read(&barrier_cbs_count) == 0 ||
1504 torture_must_stop());
1505 if (torture_must_stop())
1506 break;
1507 n_barrier_attempts++;
1508 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
1509 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
1510 n_rcu_torture_barrier_error++;
1511 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
1512 atomic_read(&barrier_cbs_invoked),
1513 n_barrier_cbs);
1514 WARN_ON_ONCE(1);
1515 }
1516 n_barrier_successes++;
1517 schedule_timeout_interruptible(HZ / 10);
1518 } while (!torture_must_stop());
1519 torture_kthread_stopping("rcu_torture_barrier");
1520 return 0;
1521 }
1522
1523 /* Initialize RCU barrier testing. */
1524 static int rcu_torture_barrier_init(void)
1525 {
1526 int i;
1527 int ret;
1528
1529 if (n_barrier_cbs <= 0)
1530 return 0;
1531 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
1532 pr_alert("%s" TORTURE_FLAG
1533 " Call or barrier ops missing for %s,\n",
1534 torture_type, cur_ops->name);
1535 pr_alert("%s" TORTURE_FLAG
1536 " RCU barrier testing omitted from run.\n",
1537 torture_type);
1538 return 0;
1539 }
1540 atomic_set(&barrier_cbs_count, 0);
1541 atomic_set(&barrier_cbs_invoked, 0);
1542 barrier_cbs_tasks =
1543 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_tasks[0]),
1544 GFP_KERNEL);
1545 barrier_cbs_wq =
1546 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_wq[0]),
1547 GFP_KERNEL);
1548 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
1549 return -ENOMEM;
1550 for (i = 0; i < n_barrier_cbs; i++) {
1551 init_waitqueue_head(&barrier_cbs_wq[i]);
1552 ret = torture_create_kthread(rcu_torture_barrier_cbs,
1553 (void *)(long)i,
1554 barrier_cbs_tasks[i]);
1555 if (ret)
1556 return ret;
1557 }
1558 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
1559 }
1560
1561 /* Clean up after RCU barrier testing. */
1562 static void rcu_torture_barrier_cleanup(void)
1563 {
1564 int i;
1565
1566 torture_stop_kthread(rcu_torture_barrier, barrier_task);
1567 if (barrier_cbs_tasks != NULL) {
1568 for (i = 0; i < n_barrier_cbs; i++)
1569 torture_stop_kthread(rcu_torture_barrier_cbs,
1570 barrier_cbs_tasks[i]);
1571 kfree(barrier_cbs_tasks);
1572 barrier_cbs_tasks = NULL;
1573 }
1574 if (barrier_cbs_wq != NULL) {
1575 kfree(barrier_cbs_wq);
1576 barrier_cbs_wq = NULL;
1577 }
1578 }
1579
1580 static int rcutorture_cpu_notify(struct notifier_block *self,
1581 unsigned long action, void *hcpu)
1582 {
1583 long cpu = (long)hcpu;
1584
1585 switch (action & ~CPU_TASKS_FROZEN) {
1586 case CPU_ONLINE:
1587 case CPU_DOWN_FAILED:
1588 (void)rcutorture_booster_init(cpu);
1589 break;
1590 case CPU_DOWN_PREPARE:
1591 rcutorture_booster_cleanup(cpu);
1592 break;
1593 default:
1594 break;
1595 }
1596 return NOTIFY_OK;
1597 }
1598
1599 static struct notifier_block rcutorture_cpu_nb = {
1600 .notifier_call = rcutorture_cpu_notify,
1601 };
1602
1603 static void
1604 rcu_torture_cleanup(void)
1605 {
1606 int i;
1607
1608 rcutorture_record_test_transition();
1609 if (torture_cleanup_begin()) {
1610 if (cur_ops->cb_barrier != NULL)
1611 cur_ops->cb_barrier();
1612 return;
1613 }
1614
1615 rcu_torture_barrier_cleanup();
1616 torture_stop_kthread(rcu_torture_stall, stall_task);
1617 torture_stop_kthread(rcu_torture_writer, writer_task);
1618
1619 if (reader_tasks) {
1620 for (i = 0; i < nrealreaders; i++)
1621 torture_stop_kthread(rcu_torture_reader,
1622 reader_tasks[i]);
1623 kfree(reader_tasks);
1624 }
1625 rcu_torture_current = NULL;
1626
1627 if (fakewriter_tasks) {
1628 for (i = 0; i < nfakewriters; i++) {
1629 torture_stop_kthread(rcu_torture_fakewriter,
1630 fakewriter_tasks[i]);
1631 }
1632 kfree(fakewriter_tasks);
1633 fakewriter_tasks = NULL;
1634 }
1635
1636 torture_stop_kthread(rcu_torture_stats, stats_task);
1637 torture_stop_kthread(rcu_torture_fqs, fqs_task);
1638 for (i = 0; i < ncbflooders; i++)
1639 torture_stop_kthread(rcu_torture_cbflood, cbflood_task[i]);
1640 if ((test_boost == 1 && cur_ops->can_boost) ||
1641 test_boost == 2) {
1642 unregister_cpu_notifier(&rcutorture_cpu_nb);
1643 for_each_possible_cpu(i)
1644 rcutorture_booster_cleanup(i);
1645 }
1646
1647 /*
1648 * Wait for all RCU callbacks to fire, then do flavor-specific
1649 * cleanup operations.
1650 */
1651 if (cur_ops->cb_barrier != NULL)
1652 cur_ops->cb_barrier();
1653 if (cur_ops->cleanup != NULL)
1654 cur_ops->cleanup();
1655
1656 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
1657
1658 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
1659 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
1660 else if (torture_onoff_failures())
1661 rcu_torture_print_module_parms(cur_ops,
1662 "End of test: RCU_HOTPLUG");
1663 else
1664 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
1665 torture_cleanup_end();
1666 }
1667
1668 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1669 static void rcu_torture_leak_cb(struct rcu_head *rhp)
1670 {
1671 }
1672
1673 static void rcu_torture_err_cb(struct rcu_head *rhp)
1674 {
1675 /*
1676 * This -might- happen due to race conditions, but is unlikely.
1677 * The scenario that leads to this happening is that the
1678 * first of the pair of duplicate callbacks is queued,
1679 * someone else starts a grace period that includes that
1680 * callback, then the second of the pair must wait for the
1681 * next grace period. Unlikely, but can happen. If it
1682 * does happen, the debug-objects subsystem won't have splatted.
1683 */
1684 pr_alert("rcutorture: duplicated callback was invoked.\n");
1685 }
1686 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1687
1688 /*
1689 * Verify that double-free causes debug-objects to complain, but only
1690 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
1691 * cannot be carried out.
1692 */
1693 static void rcu_test_debug_objects(void)
1694 {
1695 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1696 struct rcu_head rh1;
1697 struct rcu_head rh2;
1698
1699 init_rcu_head_on_stack(&rh1);
1700 init_rcu_head_on_stack(&rh2);
1701 pr_alert("rcutorture: WARN: Duplicate call_rcu() test starting.\n");
1702
1703 /* Try to queue the rh2 pair of callbacks for the same grace period. */
1704 preempt_disable(); /* Prevent preemption from interrupting test. */
1705 rcu_read_lock(); /* Make it impossible to finish a grace period. */
1706 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
1707 local_irq_disable(); /* Make it harder to start a new grace period. */
1708 call_rcu(&rh2, rcu_torture_leak_cb);
1709 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
1710 local_irq_enable();
1711 rcu_read_unlock();
1712 preempt_enable();
1713
1714 /* Wait for them all to get done so we can safely return. */
1715 rcu_barrier();
1716 pr_alert("rcutorture: WARN: Duplicate call_rcu() test complete.\n");
1717 destroy_rcu_head_on_stack(&rh1);
1718 destroy_rcu_head_on_stack(&rh2);
1719 #else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1720 pr_alert("rcutorture: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n");
1721 #endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1722 }
1723
1724 static int __init
1725 rcu_torture_init(void)
1726 {
1727 int i;
1728 int cpu;
1729 int firsterr = 0;
1730 static struct rcu_torture_ops *torture_ops[] = {
1731 &rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops,
1732 &sched_ops, RCUTORTURE_TASKS_OPS
1733 };
1734
1735 if (!torture_init_begin(torture_type, verbose, &torture_runnable))
1736 return -EBUSY;
1737
1738 /* Process args and tell the world that the torturer is on the job. */
1739 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1740 cur_ops = torture_ops[i];
1741 if (strcmp(torture_type, cur_ops->name) == 0)
1742 break;
1743 }
1744 if (i == ARRAY_SIZE(torture_ops)) {
1745 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
1746 torture_type);
1747 pr_alert("rcu-torture types:");
1748 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1749 pr_alert(" %s", torture_ops[i]->name);
1750 pr_alert("\n");
1751 firsterr = -EINVAL;
1752 goto unwind;
1753 }
1754 if (cur_ops->fqs == NULL && fqs_duration != 0) {
1755 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
1756 fqs_duration = 0;
1757 }
1758 if (cur_ops->init)
1759 cur_ops->init();
1760
1761 if (nreaders >= 0) {
1762 nrealreaders = nreaders;
1763 } else {
1764 nrealreaders = num_online_cpus() - 2 - nreaders;
1765 if (nrealreaders <= 0)
1766 nrealreaders = 1;
1767 }
1768 rcu_torture_print_module_parms(cur_ops, "Start of test");
1769
1770 /* Set up the freelist. */
1771
1772 INIT_LIST_HEAD(&rcu_torture_freelist);
1773 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1774 rcu_tortures[i].rtort_mbtest = 0;
1775 list_add_tail(&rcu_tortures[i].rtort_free,
1776 &rcu_torture_freelist);
1777 }
1778
1779 /* Initialize the statistics so that each run gets its own numbers. */
1780
1781 rcu_torture_current = NULL;
1782 rcu_torture_current_version = 0;
1783 atomic_set(&n_rcu_torture_alloc, 0);
1784 atomic_set(&n_rcu_torture_alloc_fail, 0);
1785 atomic_set(&n_rcu_torture_free, 0);
1786 atomic_set(&n_rcu_torture_mberror, 0);
1787 atomic_set(&n_rcu_torture_error, 0);
1788 n_rcu_torture_barrier_error = 0;
1789 n_rcu_torture_boost_ktrerror = 0;
1790 n_rcu_torture_boost_rterror = 0;
1791 n_rcu_torture_boost_failure = 0;
1792 n_rcu_torture_boosts = 0;
1793 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1794 atomic_set(&rcu_torture_wcount[i], 0);
1795 for_each_possible_cpu(cpu) {
1796 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1797 per_cpu(rcu_torture_count, cpu)[i] = 0;
1798 per_cpu(rcu_torture_batch, cpu)[i] = 0;
1799 }
1800 }
1801
1802 /* Start up the kthreads. */
1803
1804 firsterr = torture_create_kthread(rcu_torture_writer, NULL,
1805 writer_task);
1806 if (firsterr)
1807 goto unwind;
1808 if (nfakewriters > 0) {
1809 fakewriter_tasks = kzalloc(nfakewriters *
1810 sizeof(fakewriter_tasks[0]),
1811 GFP_KERNEL);
1812 if (fakewriter_tasks == NULL) {
1813 VERBOSE_TOROUT_ERRSTRING("out of memory");
1814 firsterr = -ENOMEM;
1815 goto unwind;
1816 }
1817 }
1818 for (i = 0; i < nfakewriters; i++) {
1819 firsterr = torture_create_kthread(rcu_torture_fakewriter,
1820 NULL, fakewriter_tasks[i]);
1821 if (firsterr)
1822 goto unwind;
1823 }
1824 reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
1825 GFP_KERNEL);
1826 if (reader_tasks == NULL) {
1827 VERBOSE_TOROUT_ERRSTRING("out of memory");
1828 firsterr = -ENOMEM;
1829 goto unwind;
1830 }
1831 for (i = 0; i < nrealreaders; i++) {
1832 firsterr = torture_create_kthread(rcu_torture_reader, NULL,
1833 reader_tasks[i]);
1834 if (firsterr)
1835 goto unwind;
1836 }
1837 if (stat_interval > 0) {
1838 firsterr = torture_create_kthread(rcu_torture_stats, NULL,
1839 stats_task);
1840 if (firsterr)
1841 goto unwind;
1842 }
1843 if (test_no_idle_hz && shuffle_interval > 0) {
1844 firsterr = torture_shuffle_init(shuffle_interval * HZ);
1845 if (firsterr)
1846 goto unwind;
1847 }
1848 if (stutter < 0)
1849 stutter = 0;
1850 if (stutter) {
1851 firsterr = torture_stutter_init(stutter * HZ);
1852 if (firsterr)
1853 goto unwind;
1854 }
1855 if (fqs_duration < 0)
1856 fqs_duration = 0;
1857 if (fqs_duration) {
1858 /* Create the fqs thread */
1859 firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
1860 fqs_task);
1861 if (firsterr)
1862 goto unwind;
1863 }
1864 if (test_boost_interval < 1)
1865 test_boost_interval = 1;
1866 if (test_boost_duration < 2)
1867 test_boost_duration = 2;
1868 if ((test_boost == 1 && cur_ops->can_boost) ||
1869 test_boost == 2) {
1870
1871 boost_starttime = jiffies + test_boost_interval * HZ;
1872 register_cpu_notifier(&rcutorture_cpu_nb);
1873 for_each_possible_cpu(i) {
1874 if (cpu_is_offline(i))
1875 continue; /* Heuristic: CPU can go offline. */
1876 firsterr = rcutorture_booster_init(i);
1877 if (firsterr)
1878 goto unwind;
1879 }
1880 }
1881 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
1882 if (firsterr)
1883 goto unwind;
1884 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval * HZ);
1885 if (firsterr)
1886 goto unwind;
1887 firsterr = rcu_torture_stall_init();
1888 if (firsterr)
1889 goto unwind;
1890 firsterr = rcu_torture_barrier_init();
1891 if (firsterr)
1892 goto unwind;
1893 if (object_debug)
1894 rcu_test_debug_objects();
1895 if (cbflood_n_burst > 0) {
1896 /* Create the cbflood threads */
1897 ncbflooders = (num_online_cpus() + 3) / 4;
1898 cbflood_task = kcalloc(ncbflooders, sizeof(*cbflood_task),
1899 GFP_KERNEL);
1900 if (!cbflood_task) {
1901 VERBOSE_TOROUT_ERRSTRING("out of memory");
1902 firsterr = -ENOMEM;
1903 goto unwind;
1904 }
1905 for (i = 0; i < ncbflooders; i++) {
1906 firsterr = torture_create_kthread(rcu_torture_cbflood,
1907 NULL,
1908 cbflood_task[i]);
1909 if (firsterr)
1910 goto unwind;
1911 }
1912 }
1913 rcutorture_record_test_transition();
1914 torture_init_end();
1915 return 0;
1916
1917 unwind:
1918 torture_init_end();
1919 rcu_torture_cleanup();
1920 return firsterr;
1921 }
1922
1923 module_init(rcu_torture_init);
1924 module_exit(rcu_torture_cleanup);
Linux with added FPC-III support