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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
54MODULE_LICENSE("GPL");
55MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
56
57
58torture_param(int, cbflood_inter_holdoff, HZ,
59 "Holdoff between floods (jiffies)");
60torture_param(int, cbflood_intra_holdoff, 1,
61 "Holdoff between bursts (jiffies)");
62torture_param(int, cbflood_n_burst, 3, "# bursts in flood, zero to disable");
63torture_param(int, cbflood_n_per_burst, 20000,
64 "# callbacks per burst in flood");
65torture_param(int, fqs_duration, 0,
66 "Duration of fqs bursts (us), 0 to disable");
67torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
68torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
69torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
70torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
71torture_param(bool, gp_normal, false,
72 "Use normal (non-expedited) GP wait primitives");
73torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
74torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
75torture_param(int, n_barrier_cbs, 0,
76 "# of callbacks/kthreads for barrier testing");
77torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
78torture_param(int, nreaders, -1, "Number of RCU reader threads");
79torture_param(int, object_debug, 0,
80 "Enable debug-object double call_rcu() testing");
81torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
82torture_param(int, onoff_interval, 0,
83 "Time between CPU hotplugs (s), 0=disable");
84torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
85torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
86torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
87torture_param(int, stall_cpu_holdoff, 10,
88 "Time to wait before starting stall (s).");
89torture_param(int, stat_interval, 60,
90 "Number of seconds between stats printk()s");
91torture_param(int, stutter, 5, "Number of seconds to run/halt test");
92torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
93torture_param(int, test_boost_duration, 4,
94 "Duration of each boost test, seconds.");
95torture_param(int, test_boost_interval, 7,
96 "Interval between boost tests, seconds.");
97torture_param(bool, test_no_idle_hz, true,
98 "Test support for tickless idle CPUs");
99torture_param(bool, verbose, true,
100 "Enable verbose debugging printk()s");
101
102static char *torture_type = "rcu";
103module_param(torture_type, charp, 0444);
104MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, ...)");
105
106static int nrealreaders;
107static int ncbflooders;
108static struct task_struct *writer_task;
109static struct task_struct **fakewriter_tasks;
110static struct task_struct **reader_tasks;
111static struct task_struct *stats_task;
112static struct task_struct **cbflood_task;
113static struct task_struct *fqs_task;
114static struct task_struct *boost_tasks[NR_CPUS];
115static struct task_struct *stall_task;
116static struct task_struct **barrier_cbs_tasks;
117static struct task_struct *barrier_task;
118
119#define RCU_TORTURE_PIPE_LEN 10
120
121struct 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
128static LIST_HEAD(rcu_torture_freelist);
129static struct rcu_torture __rcu *rcu_torture_current;
130static unsigned long rcu_torture_current_version;
131static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
132static DEFINE_SPINLOCK(rcu_torture_lock);
133static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) = { 0 };
134static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) = { 0 };
135static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
136static atomic_t n_rcu_torture_alloc;
137static atomic_t n_rcu_torture_alloc_fail;
138static atomic_t n_rcu_torture_free;
139static atomic_t n_rcu_torture_mberror;
140static atomic_t n_rcu_torture_error;
141static long n_rcu_torture_barrier_error;
142static long n_rcu_torture_boost_ktrerror;
143static long n_rcu_torture_boost_rterror;
144static long n_rcu_torture_boost_failure;
145static long n_rcu_torture_boosts;
146static long n_rcu_torture_timers;
147static long n_barrier_attempts;
148static long n_barrier_successes;
149static atomic_long_t n_cbfloods;
150static struct list_head rcu_torture_removed;
151
152static 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
163static 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
176static 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#if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
186#define RCUTORTURE_RUNNABLE_INIT 1
187#else
188#define RCUTORTURE_RUNNABLE_INIT 0
189#endif
190static int torture_runnable = RCUTORTURE_RUNNABLE_INIT;
191module_param(torture_runnable, int, 0444);
192MODULE_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
201static u64 notrace rcu_trace_clock_local(void)
202{
203 u64 ts = trace_clock_local();
204 unsigned long __maybe_unused ts_rem = do_div(ts, NSEC_PER_USEC);
205 return ts;
206}
207#else /* #ifdef CONFIG_RCU_TRACE */
208static u64 notrace rcu_trace_clock_local(void)
209{
210 return 0ULL;
211}
212#endif /* #else #ifdef CONFIG_RCU_TRACE */
213
214static unsigned long boost_starttime; /* jiffies of next boost test start. */
215static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
216 /* and boost task create/destroy. */
217static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
218static bool barrier_phase; /* Test phase. */
219static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
220static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
221static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
222
223/*
224 * Allocate an element from the rcu_tortures pool.
225 */
226static struct rcu_torture *
227rcu_torture_alloc(void)
228{
229 struct list_head *p;
230
231 spin_lock_bh(&rcu_torture_lock);
232 if (list_empty(&rcu_torture_freelist)) {
233 atomic_inc(&n_rcu_torture_alloc_fail);
234 spin_unlock_bh(&rcu_torture_lock);
235 return NULL;
236 }
237 atomic_inc(&n_rcu_torture_alloc);
238 p = rcu_torture_freelist.next;
239 list_del_init(p);
240 spin_unlock_bh(&rcu_torture_lock);
241 return container_of(p, struct rcu_torture, rtort_free);
242}
243
244/*
245 * Free an element to the rcu_tortures pool.
246 */
247static void
248rcu_torture_free(struct rcu_torture *p)
249{
250 atomic_inc(&n_rcu_torture_free);
251 spin_lock_bh(&rcu_torture_lock);
252 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
253 spin_unlock_bh(&rcu_torture_lock);
254}
255
256/*
257 * Operations vector for selecting different types of tests.
258 */
259
260struct rcu_torture_ops {
261 int ttype;
262 void (*init)(void);
263 void (*cleanup)(void);
264 int (*readlock)(void);
265 void (*read_delay)(struct torture_random_state *rrsp);
266 void (*readunlock)(int idx);
267 unsigned long (*started)(void);
268 unsigned long (*completed)(void);
269 void (*deferred_free)(struct rcu_torture *p);
270 void (*sync)(void);
271 void (*exp_sync)(void);
272 unsigned long (*get_state)(void);
273 void (*cond_sync)(unsigned long oldstate);
274 call_rcu_func_t call;
275 void (*cb_barrier)(void);
276 void (*fqs)(void);
277 void (*stats)(void);
278 int irq_capable;
279 int can_boost;
280 const char *name;
281};
282
283static struct rcu_torture_ops *cur_ops;
284
285/*
286 * Definitions for rcu torture testing.
287 */
288
289static int rcu_torture_read_lock(void) __acquires(RCU)
290{
291 rcu_read_lock();
292 return 0;
293}
294
295static void rcu_read_delay(struct torture_random_state *rrsp)
296{
297 const unsigned long shortdelay_us = 200;
298 const unsigned long longdelay_ms = 50;
299
300 /* We want a short delay sometimes to make a reader delay the grace
301 * period, and we want a long delay occasionally to trigger
302 * force_quiescent_state. */
303
304 if (!(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms)))
305 mdelay(longdelay_ms);
306 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
307 udelay(shortdelay_us);
308#ifdef CONFIG_PREEMPT
309 if (!preempt_count() &&
310 !(torture_random(rrsp) % (nrealreaders * 20000)))
311 preempt_schedule(); /* No QS if preempt_disable() in effect */
312#endif
313}
314
315static void rcu_torture_read_unlock(int idx) __releases(RCU)
316{
317 rcu_read_unlock();
318}
319
320/*
321 * Update callback in the pipe. This should be invoked after a grace period.
322 */
323static bool
324rcu_torture_pipe_update_one(struct rcu_torture *rp)
325{
326 int i;
327
328 i = rp->rtort_pipe_count;
329 if (i > RCU_TORTURE_PIPE_LEN)
330 i = RCU_TORTURE_PIPE_LEN;
331 atomic_inc(&rcu_torture_wcount[i]);
332 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
333 rp->rtort_mbtest = 0;
334 return true;
335 }
336 return false;
337}
338
339/*
340 * Update all callbacks in the pipe. Suitable for synchronous grace-period
341 * primitives.
342 */
343static void
344rcu_torture_pipe_update(struct rcu_torture *old_rp)
345{
346 struct rcu_torture *rp;
347 struct rcu_torture *rp1;
348
349 if (old_rp)
350 list_add(&old_rp->rtort_free, &rcu_torture_removed);
351 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
352 if (rcu_torture_pipe_update_one(rp)) {
353 list_del(&rp->rtort_free);
354 rcu_torture_free(rp);
355 }
356 }
357}
358
359static void
360rcu_torture_cb(struct rcu_head *p)
361{
362 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
363
364 if (torture_must_stop_irq()) {
365 /* Test is ending, just drop callbacks on the floor. */
366 /* The next initialization will pick up the pieces. */
367 return;
368 }
369 if (rcu_torture_pipe_update_one(rp))
370 rcu_torture_free(rp);
371 else
372 cur_ops->deferred_free(rp);
373}
374
375static unsigned long rcu_no_completed(void)
376{
377 return 0;
378}
379
380static void rcu_torture_deferred_free(struct rcu_torture *p)
381{
382 call_rcu(&p->rtort_rcu, rcu_torture_cb);
383}
384
385static void rcu_sync_torture_init(void)
386{
387 INIT_LIST_HEAD(&rcu_torture_removed);
388}
389
390static struct rcu_torture_ops rcu_ops = {
391 .ttype = RCU_FLAVOR,
392 .init = rcu_sync_torture_init,
393 .readlock = rcu_torture_read_lock,
394 .read_delay = rcu_read_delay,
395 .readunlock = rcu_torture_read_unlock,
396 .started = rcu_batches_started,
397 .completed = rcu_batches_completed,
398 .deferred_free = rcu_torture_deferred_free,
399 .sync = synchronize_rcu,
400 .exp_sync = synchronize_rcu_expedited,
401 .get_state = get_state_synchronize_rcu,
402 .cond_sync = cond_synchronize_rcu,
403 .call = call_rcu,
404 .cb_barrier = rcu_barrier,
405 .fqs = rcu_force_quiescent_state,
406 .stats = NULL,
407 .irq_capable = 1,
408 .can_boost = rcu_can_boost(),
409 .name = "rcu"
410};
411
412/*
413 * Definitions for rcu_bh torture testing.
414 */
415
416static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
417{
418 rcu_read_lock_bh();
419 return 0;
420}
421
422static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
423{
424 rcu_read_unlock_bh();
425}
426
427static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
428{
429 call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
430}
431
432static struct rcu_torture_ops rcu_bh_ops = {
433 .ttype = RCU_BH_FLAVOR,
434 .init = rcu_sync_torture_init,
435 .readlock = rcu_bh_torture_read_lock,
436 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
437 .readunlock = rcu_bh_torture_read_unlock,
438 .started = rcu_batches_started_bh,
439 .completed = rcu_batches_completed_bh,
440 .deferred_free = rcu_bh_torture_deferred_free,
441 .sync = synchronize_rcu_bh,
442 .exp_sync = synchronize_rcu_bh_expedited,
443 .call = call_rcu_bh,
444 .cb_barrier = rcu_barrier_bh,
445 .fqs = rcu_bh_force_quiescent_state,
446 .stats = NULL,
447 .irq_capable = 1,
448 .name = "rcu_bh"
449};
450
451/*
452 * Don't even think about trying any of these in real life!!!
453 * The names includes "busted", and they really means it!
454 * The only purpose of these functions is to provide a buggy RCU
455 * implementation to make sure that rcutorture correctly emits
456 * buggy-RCU error messages.
457 */
458static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
459{
460 /* This is a deliberate bug for testing purposes only! */
461 rcu_torture_cb(&p->rtort_rcu);
462}
463
464static void synchronize_rcu_busted(void)
465{
466 /* This is a deliberate bug for testing purposes only! */
467}
468
469static void
470call_rcu_busted(struct rcu_head *head, rcu_callback_t func)
471{
472 /* This is a deliberate bug for testing purposes only! */
473 func(head);
474}
475
476static struct rcu_torture_ops rcu_busted_ops = {
477 .ttype = INVALID_RCU_FLAVOR,
478 .init = rcu_sync_torture_init,
479 .readlock = rcu_torture_read_lock,
480 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
481 .readunlock = rcu_torture_read_unlock,
482 .started = rcu_no_completed,
483 .completed = rcu_no_completed,
484 .deferred_free = rcu_busted_torture_deferred_free,
485 .sync = synchronize_rcu_busted,
486 .exp_sync = synchronize_rcu_busted,
487 .call = call_rcu_busted,
488 .cb_barrier = NULL,
489 .fqs = NULL,
490 .stats = NULL,
491 .irq_capable = 1,
492 .name = "rcu_busted"
493};
494
495/*
496 * Definitions for srcu torture testing.
497 */
498
499DEFINE_STATIC_SRCU(srcu_ctl);
500static struct srcu_struct srcu_ctld;
501static struct srcu_struct *srcu_ctlp = &srcu_ctl;
502
503static int srcu_torture_read_lock(void) __acquires(srcu_ctlp)
504{
505 return srcu_read_lock(srcu_ctlp);
506}
507
508static void srcu_read_delay(struct torture_random_state *rrsp)
509{
510 long delay;
511 const long uspertick = 1000000 / HZ;
512 const long longdelay = 10;
513
514 /* We want there to be long-running readers, but not all the time. */
515
516 delay = torture_random(rrsp) %
517 (nrealreaders * 2 * longdelay * uspertick);
518 if (!delay)
519 schedule_timeout_interruptible(longdelay);
520 else
521 rcu_read_delay(rrsp);
522}
523
524static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp)
525{
526 srcu_read_unlock(srcu_ctlp, idx);
527}
528
529static unsigned long srcu_torture_completed(void)
530{
531 return srcu_batches_completed(srcu_ctlp);
532}
533
534static void srcu_torture_deferred_free(struct rcu_torture *rp)
535{
536 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
537}
538
539static void srcu_torture_synchronize(void)
540{
541 synchronize_srcu(srcu_ctlp);
542}
543
544static void srcu_torture_call(struct rcu_head *head,
545 rcu_callback_t func)
546{
547 call_srcu(srcu_ctlp, head, func);
548}
549
550static void srcu_torture_barrier(void)
551{
552 srcu_barrier(srcu_ctlp);
553}
554
555static void srcu_torture_stats(void)
556{
557 int cpu;
558 int idx = srcu_ctlp->completed & 0x1;
559
560 pr_alert("%s%s per-CPU(idx=%d):",
561 torture_type, TORTURE_FLAG, idx);
562 for_each_possible_cpu(cpu) {
563 long c0, c1;
564
565 c0 = (long)per_cpu_ptr(srcu_ctlp->per_cpu_ref, cpu)->c[!idx];
566 c1 = (long)per_cpu_ptr(srcu_ctlp->per_cpu_ref, cpu)->c[idx];
567 pr_cont(" %d(%ld,%ld)", cpu, c0, c1);
568 }
569 pr_cont("\n");
570}
571
572static void srcu_torture_synchronize_expedited(void)
573{
574 synchronize_srcu_expedited(srcu_ctlp);
575}
576
577static struct rcu_torture_ops srcu_ops = {
578 .ttype = SRCU_FLAVOR,
579 .init = rcu_sync_torture_init,
580 .readlock = srcu_torture_read_lock,
581 .read_delay = srcu_read_delay,
582 .readunlock = srcu_torture_read_unlock,
583 .started = NULL,
584 .completed = srcu_torture_completed,
585 .deferred_free = srcu_torture_deferred_free,
586 .sync = srcu_torture_synchronize,
587 .exp_sync = srcu_torture_synchronize_expedited,
588 .call = srcu_torture_call,
589 .cb_barrier = srcu_torture_barrier,
590 .stats = srcu_torture_stats,
591 .name = "srcu"
592};
593
594static void srcu_torture_init(void)
595{
596 rcu_sync_torture_init();
597 WARN_ON(init_srcu_struct(&srcu_ctld));
598 srcu_ctlp = &srcu_ctld;
599}
600
601static void srcu_torture_cleanup(void)
602{
603 cleanup_srcu_struct(&srcu_ctld);
604 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
605}
606
607/* As above, but dynamically allocated. */
608static struct rcu_torture_ops srcud_ops = {
609 .ttype = SRCU_FLAVOR,
610 .init = srcu_torture_init,
611 .cleanup = srcu_torture_cleanup,
612 .readlock = srcu_torture_read_lock,
613 .read_delay = srcu_read_delay,
614 .readunlock = srcu_torture_read_unlock,
615 .started = NULL,
616 .completed = srcu_torture_completed,
617 .deferred_free = srcu_torture_deferred_free,
618 .sync = srcu_torture_synchronize,
619 .exp_sync = srcu_torture_synchronize_expedited,
620 .call = srcu_torture_call,
621 .cb_barrier = srcu_torture_barrier,
622 .stats = srcu_torture_stats,
623 .name = "srcud"
624};
625
626/*
627 * Definitions for sched torture testing.
628 */
629
630static int sched_torture_read_lock(void)
631{
632 preempt_disable();
633 return 0;
634}
635
636static void sched_torture_read_unlock(int idx)
637{
638 preempt_enable();
639}
640
641static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
642{
643 call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
644}
645
646static 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#ifdef CONFIG_TASKS_RCU
668
669/*
670 * Definitions for RCU-tasks torture testing.
671 */
672
673static int tasks_torture_read_lock(void)
674{
675 return 0;
676}
677
678static void tasks_torture_read_unlock(int idx)
679{
680}
681
682static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
683{
684 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
685}
686
687static struct rcu_torture_ops tasks_ops = {
688 .ttype = RCU_TASKS_FLAVOR,
689 .init = rcu_sync_torture_init,
690 .readlock = tasks_torture_read_lock,
691 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
692 .readunlock = tasks_torture_read_unlock,
693 .started = rcu_no_completed,
694 .completed = rcu_no_completed,
695 .deferred_free = rcu_tasks_torture_deferred_free,
696 .sync = synchronize_rcu_tasks,
697 .exp_sync = synchronize_rcu_tasks,
698 .call = call_rcu_tasks,
699 .cb_barrier = rcu_barrier_tasks,
700 .fqs = NULL,
701 .stats = NULL,
702 .irq_capable = 1,
703 .name = "tasks"
704};
705
706#define RCUTORTURE_TASKS_OPS &tasks_ops,
707
708static bool __maybe_unused torturing_tasks(void)
709{
710 return cur_ops == &tasks_ops;
711}
712
713#else /* #ifdef CONFIG_TASKS_RCU */
714
715#define RCUTORTURE_TASKS_OPS
716
717static bool __maybe_unused torturing_tasks(void)
718{
719 return false;
720}
721
722#endif /* #else #ifdef CONFIG_TASKS_RCU */
723
724/*
725 * RCU torture priority-boost testing. Runs one real-time thread per
726 * CPU for moderate bursts, repeatedly registering RCU callbacks and
727 * spinning waiting for them to be invoked. If a given callback takes
728 * too long to be invoked, we assume that priority inversion has occurred.
729 */
730
731struct rcu_boost_inflight {
732 struct rcu_head rcu;
733 int inflight;
734};
735
736static void rcu_torture_boost_cb(struct rcu_head *head)
737{
738 struct rcu_boost_inflight *rbip =
739 container_of(head, struct rcu_boost_inflight, rcu);
740
741 /* Ensure RCU-core accesses precede clearing ->inflight */
742 smp_store_release(&rbip->inflight, 0);
743}
744
745static int rcu_torture_boost(void *arg)
746{
747 unsigned long call_rcu_time;
748 unsigned long endtime;
749 unsigned long oldstarttime;
750 struct rcu_boost_inflight rbi = { .inflight = 0 };
751 struct sched_param sp;
752
753 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
754
755 /* Set real-time priority. */
756 sp.sched_priority = 1;
757 if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
758 VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!");
759 n_rcu_torture_boost_rterror++;
760 }
761
762 init_rcu_head_on_stack(&rbi.rcu);
763 /* Each pass through the following loop does one boost-test cycle. */
764 do {
765 /* Wait for the next test interval. */
766 oldstarttime = boost_starttime;
767 while (ULONG_CMP_LT(jiffies, oldstarttime)) {
768 schedule_timeout_interruptible(oldstarttime - jiffies);
769 stutter_wait("rcu_torture_boost");
770 if (torture_must_stop())
771 goto checkwait;
772 }
773
774 /* Do one boost-test interval. */
775 endtime = oldstarttime + test_boost_duration * HZ;
776 call_rcu_time = jiffies;
777 while (ULONG_CMP_LT(jiffies, endtime)) {
778 /* If we don't have a callback in flight, post one. */
779 if (!smp_load_acquire(&rbi.inflight)) {
780 /* RCU core before ->inflight = 1. */
781 smp_store_release(&rbi.inflight, 1);
782 call_rcu(&rbi.rcu, rcu_torture_boost_cb);
783 if (jiffies - call_rcu_time >
784 test_boost_duration * HZ - HZ / 2) {
785 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
786 n_rcu_torture_boost_failure++;
787 }
788 call_rcu_time = jiffies;
789 }
790 stutter_wait("rcu_torture_boost");
791 if (torture_must_stop())
792 goto checkwait;
793 }
794
795 /*
796 * Set the start time of the next test interval.
797 * Yes, this is vulnerable to long delays, but such
798 * delays simply cause a false negative for the next
799 * interval. Besides, we are running at RT priority,
800 * so delays should be relatively rare.
801 */
802 while (oldstarttime == boost_starttime &&
803 !kthread_should_stop()) {
804 if (mutex_trylock(&boost_mutex)) {
805 boost_starttime = jiffies +
806 test_boost_interval * HZ;
807 n_rcu_torture_boosts++;
808 mutex_unlock(&boost_mutex);
809 break;
810 }
811 schedule_timeout_uninterruptible(1);
812 }
813
814 /* Go do the stutter. */
815checkwait: stutter_wait("rcu_torture_boost");
816 } while (!torture_must_stop());
817
818 /* Clean up and exit. */
819 while (!kthread_should_stop() || smp_load_acquire(&rbi.inflight)) {
820 torture_shutdown_absorb("rcu_torture_boost");
821 schedule_timeout_uninterruptible(1);
822 }
823 destroy_rcu_head_on_stack(&rbi.rcu);
824 torture_kthread_stopping("rcu_torture_boost");
825 return 0;
826}
827
828static void rcu_torture_cbflood_cb(struct rcu_head *rhp)
829{
830}
831
832/*
833 * RCU torture callback-flood kthread. Repeatedly induces bursts of calls
834 * to call_rcu() or analogous, increasing the probability of occurrence
835 * of callback-overflow corner cases.
836 */
837static int
838rcu_torture_cbflood(void *arg)
839{
840 int err = 1;
841 int i;
842 int j;
843 struct rcu_head *rhp;
844
845 if (cbflood_n_per_burst > 0 &&
846 cbflood_inter_holdoff > 0 &&
847 cbflood_intra_holdoff > 0 &&
848 cur_ops->call &&
849 cur_ops->cb_barrier) {
850 rhp = vmalloc(sizeof(*rhp) *
851 cbflood_n_burst * cbflood_n_per_burst);
852 err = !rhp;
853 }
854 if (err) {
855 VERBOSE_TOROUT_STRING("rcu_torture_cbflood disabled: Bad args or OOM");
856 goto wait_for_stop;
857 }
858 VERBOSE_TOROUT_STRING("rcu_torture_cbflood task started");
859 do {
860 schedule_timeout_interruptible(cbflood_inter_holdoff);
861 atomic_long_inc(&n_cbfloods);
862 WARN_ON(signal_pending(current));
863 for (i = 0; i < cbflood_n_burst; i++) {
864 for (j = 0; j < cbflood_n_per_burst; j++) {
865 cur_ops->call(&rhp[i * cbflood_n_per_burst + j],
866 rcu_torture_cbflood_cb);
867 }
868 schedule_timeout_interruptible(cbflood_intra_holdoff);
869 WARN_ON(signal_pending(current));
870 }
871 cur_ops->cb_barrier();
872 stutter_wait("rcu_torture_cbflood");
873 } while (!torture_must_stop());
874 vfree(rhp);
875wait_for_stop:
876 torture_kthread_stopping("rcu_torture_cbflood");
877 return 0;
878}
879
880/*
881 * RCU torture force-quiescent-state kthread. Repeatedly induces
882 * bursts of calls to force_quiescent_state(), increasing the probability
883 * of occurrence of some important types of race conditions.
884 */
885static int
886rcu_torture_fqs(void *arg)
887{
888 unsigned long fqs_resume_time;
889 int fqs_burst_remaining;
890
891 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
892 do {
893 fqs_resume_time = jiffies + fqs_stutter * HZ;
894 while (ULONG_CMP_LT(jiffies, fqs_resume_time) &&
895 !kthread_should_stop()) {
896 schedule_timeout_interruptible(1);
897 }
898 fqs_burst_remaining = fqs_duration;
899 while (fqs_burst_remaining > 0 &&
900 !kthread_should_stop()) {
901 cur_ops->fqs();
902 udelay(fqs_holdoff);
903 fqs_burst_remaining -= fqs_holdoff;
904 }
905 stutter_wait("rcu_torture_fqs");
906 } while (!torture_must_stop());
907 torture_kthread_stopping("rcu_torture_fqs");
908 return 0;
909}
910
911/*
912 * RCU torture writer kthread. Repeatedly substitutes a new structure
913 * for that pointed to by rcu_torture_current, freeing the old structure
914 * after a series of grace periods (the "pipeline").
915 */
916static int
917rcu_torture_writer(void *arg)
918{
919 bool can_expedite = !rcu_gp_is_expedited();
920 int expediting = 0;
921 unsigned long gp_snap;
922 bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal;
923 bool gp_sync1 = gp_sync;
924 int i;
925 struct rcu_torture *rp;
926 struct rcu_torture *old_rp;
927 static DEFINE_TORTURE_RANDOM(rand);
928 int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC,
929 RTWS_COND_GET, RTWS_SYNC };
930 int nsynctypes = 0;
931
932 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
933 if (!can_expedite) {
934 pr_alert("%s" TORTURE_FLAG
935 " Grace periods expedited from boot/sysfs for %s,\n",
936 torture_type, cur_ops->name);
937 pr_alert("%s" TORTURE_FLAG
938 " Disabled dynamic grace-period expediting.\n",
939 torture_type);
940 }
941
942 /* Initialize synctype[] array. If none set, take default. */
943 if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync1)
944 gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true;
945 if (gp_cond1 && cur_ops->get_state && cur_ops->cond_sync)
946 synctype[nsynctypes++] = RTWS_COND_GET;
947 else if (gp_cond && (!cur_ops->get_state || !cur_ops->cond_sync))
948 pr_alert("rcu_torture_writer: gp_cond without primitives.\n");
949 if (gp_exp1 && cur_ops->exp_sync)
950 synctype[nsynctypes++] = RTWS_EXP_SYNC;
951 else if (gp_exp && !cur_ops->exp_sync)
952 pr_alert("rcu_torture_writer: gp_exp without primitives.\n");
953 if (gp_normal1 && cur_ops->deferred_free)
954 synctype[nsynctypes++] = RTWS_DEF_FREE;
955 else if (gp_normal && !cur_ops->deferred_free)
956 pr_alert("rcu_torture_writer: gp_normal without primitives.\n");
957 if (gp_sync1 && cur_ops->sync)
958 synctype[nsynctypes++] = RTWS_SYNC;
959 else if (gp_sync && !cur_ops->sync)
960 pr_alert("rcu_torture_writer: gp_sync without primitives.\n");
961 if (WARN_ONCE(nsynctypes == 0,
962 "rcu_torture_writer: No update-side primitives.\n")) {
963 /*
964 * No updates primitives, so don't try updating.
965 * The resulting test won't be testing much, hence the
966 * above WARN_ONCE().
967 */
968 rcu_torture_writer_state = RTWS_STOPPING;
969 torture_kthread_stopping("rcu_torture_writer");
970 }
971
972 do {
973 rcu_torture_writer_state = RTWS_FIXED_DELAY;
974 schedule_timeout_uninterruptible(1);
975 rp = rcu_torture_alloc();
976 if (rp == NULL)
977 continue;
978 rp->rtort_pipe_count = 0;
979 rcu_torture_writer_state = RTWS_DELAY;
980 udelay(torture_random(&rand) & 0x3ff);
981 rcu_torture_writer_state = RTWS_REPLACE;
982 old_rp = rcu_dereference_check(rcu_torture_current,
983 current == writer_task);
984 rp->rtort_mbtest = 1;
985 rcu_assign_pointer(rcu_torture_current, rp);
986 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
987 if (old_rp) {
988 i = old_rp->rtort_pipe_count;
989 if (i > RCU_TORTURE_PIPE_LEN)
990 i = RCU_TORTURE_PIPE_LEN;
991 atomic_inc(&rcu_torture_wcount[i]);
992 old_rp->rtort_pipe_count++;
993 switch (synctype[torture_random(&rand) % nsynctypes]) {
994 case RTWS_DEF_FREE:
995 rcu_torture_writer_state = RTWS_DEF_FREE;
996 cur_ops->deferred_free(old_rp);
997 break;
998 case RTWS_EXP_SYNC:
999 rcu_torture_writer_state = RTWS_EXP_SYNC;
1000 cur_ops->exp_sync();
1001 rcu_torture_pipe_update(old_rp);
1002 break;
1003 case RTWS_COND_GET:
1004 rcu_torture_writer_state = RTWS_COND_GET;
1005 gp_snap = cur_ops->get_state();
1006 i = torture_random(&rand) % 16;
1007 if (i != 0)
1008 schedule_timeout_interruptible(i);
1009 udelay(torture_random(&rand) % 1000);
1010 rcu_torture_writer_state = RTWS_COND_SYNC;
1011 cur_ops->cond_sync(gp_snap);
1012 rcu_torture_pipe_update(old_rp);
1013 break;
1014 case RTWS_SYNC:
1015 rcu_torture_writer_state = RTWS_SYNC;
1016 cur_ops->sync();
1017 rcu_torture_pipe_update(old_rp);
1018 break;
1019 default:
1020 WARN_ON_ONCE(1);
1021 break;
1022 }
1023 }
1024 rcutorture_record_progress(++rcu_torture_current_version);
1025 /* Cycle through nesting levels of rcu_expedite_gp() calls. */
1026 if (can_expedite &&
1027 !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
1028 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
1029 if (expediting >= 0)
1030 rcu_expedite_gp();
1031 else
1032 rcu_unexpedite_gp();
1033 if (++expediting > 3)
1034 expediting = -expediting;
1035 }
1036 rcu_torture_writer_state = RTWS_STUTTER;
1037 stutter_wait("rcu_torture_writer");
1038 } while (!torture_must_stop());
1039 /* Reset expediting back to unexpedited. */
1040 if (expediting > 0)
1041 expediting = -expediting;
1042 while (can_expedite && expediting++ < 0)
1043 rcu_unexpedite_gp();
1044 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
1045 rcu_torture_writer_state = RTWS_STOPPING;
1046 torture_kthread_stopping("rcu_torture_writer");
1047 return 0;
1048}
1049
1050/*
1051 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
1052 * delay between calls.
1053 */
1054static int
1055rcu_torture_fakewriter(void *arg)
1056{
1057 DEFINE_TORTURE_RANDOM(rand);
1058
1059 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1060 set_user_nice(current, MAX_NICE);
1061
1062 do {
1063 schedule_timeout_uninterruptible(1 + torture_random(&rand)%10);
1064 udelay(torture_random(&rand) & 0x3ff);
1065 if (cur_ops->cb_barrier != NULL &&
1066 torture_random(&rand) % (nfakewriters * 8) == 0) {
1067 cur_ops->cb_barrier();
1068 } else if (gp_normal == gp_exp) {
1069 if (torture_random(&rand) & 0x80)
1070 cur_ops->sync();
1071 else
1072 cur_ops->exp_sync();
1073 } else if (gp_normal) {
1074 cur_ops->sync();
1075 } else {
1076 cur_ops->exp_sync();
1077 }
1078 stutter_wait("rcu_torture_fakewriter");
1079 } while (!torture_must_stop());
1080
1081 torture_kthread_stopping("rcu_torture_fakewriter");
1082 return 0;
1083}
1084
1085static void rcutorture_trace_dump(void)
1086{
1087 static atomic_t beenhere = ATOMIC_INIT(0);
1088
1089 if (atomic_read(&beenhere))
1090 return;
1091 if (atomic_xchg(&beenhere, 1) != 0)
1092 return;
1093 ftrace_dump(DUMP_ALL);
1094}
1095
1096/*
1097 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
1098 * incrementing the corresponding element of the pipeline array. The
1099 * counter in the element should never be greater than 1, otherwise, the
1100 * RCU implementation is broken.
1101 */
1102static void rcu_torture_timer(unsigned long unused)
1103{
1104 int idx;
1105 unsigned long started;
1106 unsigned long completed;
1107 static DEFINE_TORTURE_RANDOM(rand);
1108 static DEFINE_SPINLOCK(rand_lock);
1109 struct rcu_torture *p;
1110 int pipe_count;
1111 unsigned long long ts;
1112
1113 idx = cur_ops->readlock();
1114 if (cur_ops->started)
1115 started = cur_ops->started();
1116 else
1117 started = cur_ops->completed();
1118 ts = rcu_trace_clock_local();
1119 p = rcu_dereference_check(rcu_torture_current,
1120 rcu_read_lock_bh_held() ||
1121 rcu_read_lock_sched_held() ||
1122 srcu_read_lock_held(srcu_ctlp) ||
1123 torturing_tasks());
1124 if (p == NULL) {
1125 /* Leave because rcu_torture_writer is not yet underway */
1126 cur_ops->readunlock(idx);
1127 return;
1128 }
1129 if (p->rtort_mbtest == 0)
1130 atomic_inc(&n_rcu_torture_mberror);
1131 spin_lock(&rand_lock);
1132 cur_ops->read_delay(&rand);
1133 n_rcu_torture_timers++;
1134 spin_unlock(&rand_lock);
1135 preempt_disable();
1136 pipe_count = p->rtort_pipe_count;
1137 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1138 /* Should not happen, but... */
1139 pipe_count = RCU_TORTURE_PIPE_LEN;
1140 }
1141 completed = cur_ops->completed();
1142 if (pipe_count > 1) {
1143 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, ts,
1144 started, completed);
1145 rcutorture_trace_dump();
1146 }
1147 __this_cpu_inc(rcu_torture_count[pipe_count]);
1148 completed = completed - started;
1149 if (cur_ops->started)
1150 completed++;
1151 if (completed > RCU_TORTURE_PIPE_LEN) {
1152 /* Should not happen, but... */
1153 completed = RCU_TORTURE_PIPE_LEN;
1154 }
1155 __this_cpu_inc(rcu_torture_batch[completed]);
1156 preempt_enable();
1157 cur_ops->readunlock(idx);
1158}
1159
1160/*
1161 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
1162 * incrementing the corresponding element of the pipeline array. The
1163 * counter in the element should never be greater than 1, otherwise, the
1164 * RCU implementation is broken.
1165 */
1166static int
1167rcu_torture_reader(void *arg)
1168{
1169 unsigned long started;
1170 unsigned long completed;
1171 int idx;
1172 DEFINE_TORTURE_RANDOM(rand);
1173 struct rcu_torture *p;
1174 int pipe_count;
1175 struct timer_list t;
1176 unsigned long long ts;
1177
1178 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
1179 set_user_nice(current, MAX_NICE);
1180 if (irqreader && cur_ops->irq_capable)
1181 setup_timer_on_stack(&t, rcu_torture_timer, 0);
1182
1183 do {
1184 if (irqreader && cur_ops->irq_capable) {
1185 if (!timer_pending(&t))
1186 mod_timer(&t, jiffies + 1);
1187 }
1188 idx = cur_ops->readlock();
1189 if (cur_ops->started)
1190 started = cur_ops->started();
1191 else
1192 started = cur_ops->completed();
1193 ts = rcu_trace_clock_local();
1194 p = rcu_dereference_check(rcu_torture_current,
1195 rcu_read_lock_bh_held() ||
1196 rcu_read_lock_sched_held() ||
1197 srcu_read_lock_held(srcu_ctlp) ||
1198 torturing_tasks());
1199 if (p == NULL) {
1200 /* Wait for rcu_torture_writer to get underway */
1201 cur_ops->readunlock(idx);
1202 schedule_timeout_interruptible(HZ);
1203 continue;
1204 }
1205 if (p->rtort_mbtest == 0)
1206 atomic_inc(&n_rcu_torture_mberror);
1207 cur_ops->read_delay(&rand);
1208 preempt_disable();
1209 pipe_count = p->rtort_pipe_count;
1210 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1211 /* Should not happen, but... */
1212 pipe_count = RCU_TORTURE_PIPE_LEN;
1213 }
1214 completed = cur_ops->completed();
1215 if (pipe_count > 1) {
1216 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
1217 ts, started, completed);
1218 rcutorture_trace_dump();
1219 }
1220 __this_cpu_inc(rcu_torture_count[pipe_count]);
1221 completed = completed - started;
1222 if (cur_ops->started)
1223 completed++;
1224 if (completed > RCU_TORTURE_PIPE_LEN) {
1225 /* Should not happen, but... */
1226 completed = RCU_TORTURE_PIPE_LEN;
1227 }
1228 __this_cpu_inc(rcu_torture_batch[completed]);
1229 preempt_enable();
1230 cur_ops->readunlock(idx);
1231 stutter_wait("rcu_torture_reader");
1232 } while (!torture_must_stop());
1233 if (irqreader && cur_ops->irq_capable) {
1234 del_timer_sync(&t);
1235 destroy_timer_on_stack(&t);
1236 }
1237 torture_kthread_stopping("rcu_torture_reader");
1238 return 0;
1239}
1240
1241/*
1242 * Print torture statistics. Caller must ensure that there is only
1243 * one call to this function at a given time!!! This is normally
1244 * accomplished by relying on the module system to only have one copy
1245 * of the module loaded, and then by giving the rcu_torture_stats
1246 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1247 * thread is not running).
1248 */
1249static void
1250rcu_torture_stats_print(void)
1251{
1252 int cpu;
1253 int i;
1254 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1255 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1256 static unsigned long rtcv_snap = ULONG_MAX;
1257
1258 for_each_possible_cpu(cpu) {
1259 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1260 pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
1261 batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
1262 }
1263 }
1264 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
1265 if (pipesummary[i] != 0)
1266 break;
1267 }
1268
1269 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1270 pr_cont("rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
1271 rcu_torture_current,
1272 rcu_torture_current_version,
1273 list_empty(&rcu_torture_freelist),
1274 atomic_read(&n_rcu_torture_alloc),
1275 atomic_read(&n_rcu_torture_alloc_fail),
1276 atomic_read(&n_rcu_torture_free));
1277 pr_cont("rtmbe: %d rtbke: %ld rtbre: %ld ",
1278 atomic_read(&n_rcu_torture_mberror),
1279 n_rcu_torture_boost_ktrerror,
1280 n_rcu_torture_boost_rterror);
1281 pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
1282 n_rcu_torture_boost_failure,
1283 n_rcu_torture_boosts,
1284 n_rcu_torture_timers);
1285 torture_onoff_stats();
1286 pr_cont("barrier: %ld/%ld:%ld ",
1287 n_barrier_successes,
1288 n_barrier_attempts,
1289 n_rcu_torture_barrier_error);
1290 pr_cont("cbflood: %ld\n", atomic_long_read(&n_cbfloods));
1291
1292 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1293 if (atomic_read(&n_rcu_torture_mberror) != 0 ||
1294 n_rcu_torture_barrier_error != 0 ||
1295 n_rcu_torture_boost_ktrerror != 0 ||
1296 n_rcu_torture_boost_rterror != 0 ||
1297 n_rcu_torture_boost_failure != 0 ||
1298 i > 1) {
1299 pr_cont("%s", "!!! ");
1300 atomic_inc(&n_rcu_torture_error);
1301 WARN_ON_ONCE(1);
1302 }
1303 pr_cont("Reader Pipe: ");
1304 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1305 pr_cont(" %ld", pipesummary[i]);
1306 pr_cont("\n");
1307
1308 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1309 pr_cont("Reader Batch: ");
1310 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1311 pr_cont(" %ld", batchsummary[i]);
1312 pr_cont("\n");
1313
1314 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1315 pr_cont("Free-Block Circulation: ");
1316 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1317 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
1318 }
1319 pr_cont("\n");
1320
1321 if (cur_ops->stats)
1322 cur_ops->stats();
1323 if (rtcv_snap == rcu_torture_current_version &&
1324 rcu_torture_current != NULL) {
1325 int __maybe_unused flags;
1326 unsigned long __maybe_unused gpnum;
1327 unsigned long __maybe_unused completed;
1328
1329 rcutorture_get_gp_data(cur_ops->ttype,
1330 &flags, &gpnum, &completed);
1331 pr_alert("??? Writer stall state %s(%d) g%lu c%lu f%#x\n",
1332 rcu_torture_writer_state_getname(),
1333 rcu_torture_writer_state,
1334 gpnum, completed, flags);
1335 show_rcu_gp_kthreads();
1336 rcutorture_trace_dump();
1337 }
1338 rtcv_snap = rcu_torture_current_version;
1339}
1340
1341/*
1342 * Periodically prints torture statistics, if periodic statistics printing
1343 * was specified via the stat_interval module parameter.
1344 */
1345static int
1346rcu_torture_stats(void *arg)
1347{
1348 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1349 do {
1350 schedule_timeout_interruptible(stat_interval * HZ);
1351 rcu_torture_stats_print();
1352 torture_shutdown_absorb("rcu_torture_stats");
1353 } while (!torture_must_stop());
1354 torture_kthread_stopping("rcu_torture_stats");
1355 return 0;
1356}
1357
1358static inline void
1359rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1360{
1361 pr_alert("%s" TORTURE_FLAG
1362 "--- %s: nreaders=%d nfakewriters=%d "
1363 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1364 "shuffle_interval=%d stutter=%d irqreader=%d "
1365 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1366 "test_boost=%d/%d test_boost_interval=%d "
1367 "test_boost_duration=%d shutdown_secs=%d "
1368 "stall_cpu=%d stall_cpu_holdoff=%d "
1369 "n_barrier_cbs=%d "
1370 "onoff_interval=%d onoff_holdoff=%d\n",
1371 torture_type, tag, nrealreaders, nfakewriters,
1372 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1373 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1374 test_boost, cur_ops->can_boost,
1375 test_boost_interval, test_boost_duration, shutdown_secs,
1376 stall_cpu, stall_cpu_holdoff,
1377 n_barrier_cbs,
1378 onoff_interval, onoff_holdoff);
1379}
1380
1381static void rcutorture_booster_cleanup(int cpu)
1382{
1383 struct task_struct *t;
1384
1385 if (boost_tasks[cpu] == NULL)
1386 return;
1387 mutex_lock(&boost_mutex);
1388 t = boost_tasks[cpu];
1389 boost_tasks[cpu] = NULL;
1390 mutex_unlock(&boost_mutex);
1391
1392 /* This must be outside of the mutex, otherwise deadlock! */
1393 torture_stop_kthread(rcu_torture_boost, t);
1394}
1395
1396static int rcutorture_booster_init(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 */
1427static 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 pr_alert("rcu_torture_stall start.\n");
1441 rcu_read_lock();
1442 preempt_disable();
1443 while (ULONG_CMP_LT(get_seconds(), stop_at))
1444 continue; /* Induce RCU CPU stall warning. */
1445 preempt_enable();
1446 rcu_read_unlock();
1447 pr_alert("rcu_torture_stall end.\n");
1448 }
1449 torture_shutdown_absorb("rcu_torture_stall");
1450 while (!kthread_should_stop())
1451 schedule_timeout_interruptible(10 * HZ);
1452 return 0;
1453}
1454
1455/* Spawn CPU-stall kthread, if stall_cpu specified. */
1456static int __init rcu_torture_stall_init(void)
1457{
1458 if (stall_cpu <= 0)
1459 return 0;
1460 return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
1461}
1462
1463/* Callback function for RCU barrier testing. */
1464static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
1465{
1466 atomic_inc(&barrier_cbs_invoked);
1467}
1468
1469/* kthread function to register callbacks used to test RCU barriers. */
1470static int rcu_torture_barrier_cbs(void *arg)
1471{
1472 long myid = (long)arg;
1473 bool lastphase = 0;
1474 bool newphase;
1475 struct rcu_head rcu;
1476
1477 init_rcu_head_on_stack(&rcu);
1478 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
1479 set_user_nice(current, MAX_NICE);
1480 do {
1481 wait_event(barrier_cbs_wq[myid],
1482 (newphase =
1483 smp_load_acquire(&barrier_phase)) != lastphase ||
1484 torture_must_stop());
1485 lastphase = newphase;
1486 if (torture_must_stop())
1487 break;
1488 /*
1489 * The above smp_load_acquire() ensures barrier_phase load
1490 * is ordered before the folloiwng ->call().
1491 */
1492 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
1493 if (atomic_dec_and_test(&barrier_cbs_count))
1494 wake_up(&barrier_wq);
1495 } while (!torture_must_stop());
1496 if (cur_ops->cb_barrier != NULL)
1497 cur_ops->cb_barrier();
1498 destroy_rcu_head_on_stack(&rcu);
1499 torture_kthread_stopping("rcu_torture_barrier_cbs");
1500 return 0;
1501}
1502
1503/* kthread function to drive and coordinate RCU barrier testing. */
1504static int rcu_torture_barrier(void *arg)
1505{
1506 int i;
1507
1508 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
1509 do {
1510 atomic_set(&barrier_cbs_invoked, 0);
1511 atomic_set(&barrier_cbs_count, n_barrier_cbs);
1512 /* Ensure barrier_phase ordered after prior assignments. */
1513 smp_store_release(&barrier_phase, !barrier_phase);
1514 for (i = 0; i < n_barrier_cbs; i++)
1515 wake_up(&barrier_cbs_wq[i]);
1516 wait_event(barrier_wq,
1517 atomic_read(&barrier_cbs_count) == 0 ||
1518 torture_must_stop());
1519 if (torture_must_stop())
1520 break;
1521 n_barrier_attempts++;
1522 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
1523 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
1524 n_rcu_torture_barrier_error++;
1525 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
1526 atomic_read(&barrier_cbs_invoked),
1527 n_barrier_cbs);
1528 WARN_ON_ONCE(1);
1529 }
1530 n_barrier_successes++;
1531 schedule_timeout_interruptible(HZ / 10);
1532 } while (!torture_must_stop());
1533 torture_kthread_stopping("rcu_torture_barrier");
1534 return 0;
1535}
1536
1537/* Initialize RCU barrier testing. */
1538static int rcu_torture_barrier_init(void)
1539{
1540 int i;
1541 int ret;
1542
1543 if (n_barrier_cbs <= 0)
1544 return 0;
1545 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
1546 pr_alert("%s" TORTURE_FLAG
1547 " Call or barrier ops missing for %s,\n",
1548 torture_type, cur_ops->name);
1549 pr_alert("%s" TORTURE_FLAG
1550 " RCU barrier testing omitted from run.\n",
1551 torture_type);
1552 return 0;
1553 }
1554 atomic_set(&barrier_cbs_count, 0);
1555 atomic_set(&barrier_cbs_invoked, 0);
1556 barrier_cbs_tasks =
1557 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_tasks[0]),
1558 GFP_KERNEL);
1559 barrier_cbs_wq =
1560 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_wq[0]),
1561 GFP_KERNEL);
1562 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
1563 return -ENOMEM;
1564 for (i = 0; i < n_barrier_cbs; i++) {
1565 init_waitqueue_head(&barrier_cbs_wq[i]);
1566 ret = torture_create_kthread(rcu_torture_barrier_cbs,
1567 (void *)(long)i,
1568 barrier_cbs_tasks[i]);
1569 if (ret)
1570 return ret;
1571 }
1572 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
1573}
1574
1575/* Clean up after RCU barrier testing. */
1576static void rcu_torture_barrier_cleanup(void)
1577{
1578 int i;
1579
1580 torture_stop_kthread(rcu_torture_barrier, barrier_task);
1581 if (barrier_cbs_tasks != NULL) {
1582 for (i = 0; i < n_barrier_cbs; i++)
1583 torture_stop_kthread(rcu_torture_barrier_cbs,
1584 barrier_cbs_tasks[i]);
1585 kfree(barrier_cbs_tasks);
1586 barrier_cbs_tasks = NULL;
1587 }
1588 if (barrier_cbs_wq != NULL) {
1589 kfree(barrier_cbs_wq);
1590 barrier_cbs_wq = NULL;
1591 }
1592}
1593
1594static int rcutorture_cpu_notify(struct notifier_block *self,
1595 unsigned long action, void *hcpu)
1596{
1597 long cpu = (long)hcpu;
1598
1599 switch (action) {
1600 case CPU_ONLINE:
1601 case CPU_DOWN_FAILED:
1602 (void)rcutorture_booster_init(cpu);
1603 break;
1604 case CPU_DOWN_PREPARE:
1605 rcutorture_booster_cleanup(cpu);
1606 break;
1607 default:
1608 break;
1609 }
1610 return NOTIFY_OK;
1611}
1612
1613static struct notifier_block rcutorture_cpu_nb = {
1614 .notifier_call = rcutorture_cpu_notify,
1615};
1616
1617static void
1618rcu_torture_cleanup(void)
1619{
1620 int i;
1621
1622 rcutorture_record_test_transition();
1623 if (torture_cleanup_begin()) {
1624 if (cur_ops->cb_barrier != NULL)
1625 cur_ops->cb_barrier();
1626 return;
1627 }
1628
1629 rcu_torture_barrier_cleanup();
1630 torture_stop_kthread(rcu_torture_stall, stall_task);
1631 torture_stop_kthread(rcu_torture_writer, writer_task);
1632
1633 if (reader_tasks) {
1634 for (i = 0; i < nrealreaders; i++)
1635 torture_stop_kthread(rcu_torture_reader,
1636 reader_tasks[i]);
1637 kfree(reader_tasks);
1638 }
1639 rcu_torture_current = NULL;
1640
1641 if (fakewriter_tasks) {
1642 for (i = 0; i < nfakewriters; i++) {
1643 torture_stop_kthread(rcu_torture_fakewriter,
1644 fakewriter_tasks[i]);
1645 }
1646 kfree(fakewriter_tasks);
1647 fakewriter_tasks = NULL;
1648 }
1649
1650 torture_stop_kthread(rcu_torture_stats, stats_task);
1651 torture_stop_kthread(rcu_torture_fqs, fqs_task);
1652 for (i = 0; i < ncbflooders; i++)
1653 torture_stop_kthread(rcu_torture_cbflood, cbflood_task[i]);
1654 if ((test_boost == 1 && cur_ops->can_boost) ||
1655 test_boost == 2) {
1656 unregister_cpu_notifier(&rcutorture_cpu_nb);
1657 for_each_possible_cpu(i)
1658 rcutorture_booster_cleanup(i);
1659 }
1660
1661 /*
1662 * Wait for all RCU callbacks to fire, then do flavor-specific
1663 * cleanup operations.
1664 */
1665 if (cur_ops->cb_barrier != NULL)
1666 cur_ops->cb_barrier();
1667 if (cur_ops->cleanup != NULL)
1668 cur_ops->cleanup();
1669
1670 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
1671
1672 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
1673 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
1674 else if (torture_onoff_failures())
1675 rcu_torture_print_module_parms(cur_ops,
1676 "End of test: RCU_HOTPLUG");
1677 else
1678 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
1679 torture_cleanup_end();
1680}
1681
1682#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1683static void rcu_torture_leak_cb(struct rcu_head *rhp)
1684{
1685}
1686
1687static void rcu_torture_err_cb(struct rcu_head *rhp)
1688{
1689 /*
1690 * This -might- happen due to race conditions, but is unlikely.
1691 * The scenario that leads to this happening is that the
1692 * first of the pair of duplicate callbacks is queued,
1693 * someone else starts a grace period that includes that
1694 * callback, then the second of the pair must wait for the
1695 * next grace period. Unlikely, but can happen. If it
1696 * does happen, the debug-objects subsystem won't have splatted.
1697 */
1698 pr_alert("rcutorture: duplicated callback was invoked.\n");
1699}
1700#endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1701
1702/*
1703 * Verify that double-free causes debug-objects to complain, but only
1704 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
1705 * cannot be carried out.
1706 */
1707static void rcu_test_debug_objects(void)
1708{
1709#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1710 struct rcu_head rh1;
1711 struct rcu_head rh2;
1712
1713 init_rcu_head_on_stack(&rh1);
1714 init_rcu_head_on_stack(&rh2);
1715 pr_alert("rcutorture: WARN: Duplicate call_rcu() test starting.\n");
1716
1717 /* Try to queue the rh2 pair of callbacks for the same grace period. */
1718 preempt_disable(); /* Prevent preemption from interrupting test. */
1719 rcu_read_lock(); /* Make it impossible to finish a grace period. */
1720 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
1721 local_irq_disable(); /* Make it harder to start a new grace period. */
1722 call_rcu(&rh2, rcu_torture_leak_cb);
1723 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
1724 local_irq_enable();
1725 rcu_read_unlock();
1726 preempt_enable();
1727
1728 /* Wait for them all to get done so we can safely return. */
1729 rcu_barrier();
1730 pr_alert("rcutorture: WARN: Duplicate call_rcu() test complete.\n");
1731 destroy_rcu_head_on_stack(&rh1);
1732 destroy_rcu_head_on_stack(&rh2);
1733#else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1734 pr_alert("rcutorture: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n");
1735#endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1736}
1737
1738static int __init
1739rcu_torture_init(void)
1740{
1741 int i;
1742 int cpu;
1743 int firsterr = 0;
1744 static struct rcu_torture_ops *torture_ops[] = {
1745 &rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops,
1746 &sched_ops, RCUTORTURE_TASKS_OPS
1747 };
1748
1749 if (!torture_init_begin(torture_type, verbose, &torture_runnable))
1750 return -EBUSY;
1751
1752 /* Process args and tell the world that the torturer is on the job. */
1753 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1754 cur_ops = torture_ops[i];
1755 if (strcmp(torture_type, cur_ops->name) == 0)
1756 break;
1757 }
1758 if (i == ARRAY_SIZE(torture_ops)) {
1759 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
1760 torture_type);
1761 pr_alert("rcu-torture types:");
1762 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1763 pr_alert(" %s", torture_ops[i]->name);
1764 pr_alert("\n");
1765 firsterr = -EINVAL;
1766 goto unwind;
1767 }
1768 if (cur_ops->fqs == NULL && fqs_duration != 0) {
1769 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
1770 fqs_duration = 0;
1771 }
1772 if (cur_ops->init)
1773 cur_ops->init();
1774
1775 if (nreaders >= 0) {
1776 nrealreaders = nreaders;
1777 } else {
1778 nrealreaders = num_online_cpus() - 2 - nreaders;
1779 if (nrealreaders <= 0)
1780 nrealreaders = 1;
1781 }
1782 rcu_torture_print_module_parms(cur_ops, "Start of test");
1783
1784 /* Set up the freelist. */
1785
1786 INIT_LIST_HEAD(&rcu_torture_freelist);
1787 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1788 rcu_tortures[i].rtort_mbtest = 0;
1789 list_add_tail(&rcu_tortures[i].rtort_free,
1790 &rcu_torture_freelist);
1791 }
1792
1793 /* Initialize the statistics so that each run gets its own numbers. */
1794
1795 rcu_torture_current = NULL;
1796 rcu_torture_current_version = 0;
1797 atomic_set(&n_rcu_torture_alloc, 0);
1798 atomic_set(&n_rcu_torture_alloc_fail, 0);
1799 atomic_set(&n_rcu_torture_free, 0);
1800 atomic_set(&n_rcu_torture_mberror, 0);
1801 atomic_set(&n_rcu_torture_error, 0);
1802 n_rcu_torture_barrier_error = 0;
1803 n_rcu_torture_boost_ktrerror = 0;
1804 n_rcu_torture_boost_rterror = 0;
1805 n_rcu_torture_boost_failure = 0;
1806 n_rcu_torture_boosts = 0;
1807 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1808 atomic_set(&rcu_torture_wcount[i], 0);
1809 for_each_possible_cpu(cpu) {
1810 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1811 per_cpu(rcu_torture_count, cpu)[i] = 0;
1812 per_cpu(rcu_torture_batch, cpu)[i] = 0;
1813 }
1814 }
1815
1816 /* Start up the kthreads. */
1817
1818 firsterr = torture_create_kthread(rcu_torture_writer, NULL,
1819 writer_task);
1820 if (firsterr)
1821 goto unwind;
1822 if (nfakewriters > 0) {
1823 fakewriter_tasks = kzalloc(nfakewriters *
1824 sizeof(fakewriter_tasks[0]),
1825 GFP_KERNEL);
1826 if (fakewriter_tasks == NULL) {
1827 VERBOSE_TOROUT_ERRSTRING("out of memory");
1828 firsterr = -ENOMEM;
1829 goto unwind;
1830 }
1831 }
1832 for (i = 0; i < nfakewriters; i++) {
1833 firsterr = torture_create_kthread(rcu_torture_fakewriter,
1834 NULL, fakewriter_tasks[i]);
1835 if (firsterr)
1836 goto unwind;
1837 }
1838 reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
1839 GFP_KERNEL);
1840 if (reader_tasks == NULL) {
1841 VERBOSE_TOROUT_ERRSTRING("out of memory");
1842 firsterr = -ENOMEM;
1843 goto unwind;
1844 }
1845 for (i = 0; i < nrealreaders; i++) {
1846 firsterr = torture_create_kthread(rcu_torture_reader, NULL,
1847 reader_tasks[i]);
1848 if (firsterr)
1849 goto unwind;
1850 }
1851 if (stat_interval > 0) {
1852 firsterr = torture_create_kthread(rcu_torture_stats, NULL,
1853 stats_task);
1854 if (firsterr)
1855 goto unwind;
1856 }
1857 if (test_no_idle_hz && shuffle_interval > 0) {
1858 firsterr = torture_shuffle_init(shuffle_interval * HZ);
1859 if (firsterr)
1860 goto unwind;
1861 }
1862 if (stutter < 0)
1863 stutter = 0;
1864 if (stutter) {
1865 firsterr = torture_stutter_init(stutter * HZ);
1866 if (firsterr)
1867 goto unwind;
1868 }
1869 if (fqs_duration < 0)
1870 fqs_duration = 0;
1871 if (fqs_duration) {
1872 /* Create the fqs thread */
1873 firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
1874 fqs_task);
1875 if (firsterr)
1876 goto unwind;
1877 }
1878 if (test_boost_interval < 1)
1879 test_boost_interval = 1;
1880 if (test_boost_duration < 2)
1881 test_boost_duration = 2;
1882 if ((test_boost == 1 && cur_ops->can_boost) ||
1883 test_boost == 2) {
1884
1885 boost_starttime = jiffies + test_boost_interval * HZ;
1886 register_cpu_notifier(&rcutorture_cpu_nb);
1887 for_each_possible_cpu(i) {
1888 if (cpu_is_offline(i))
1889 continue; /* Heuristic: CPU can go offline. */
1890 firsterr = rcutorture_booster_init(i);
1891 if (firsterr)
1892 goto unwind;
1893 }
1894 }
1895 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
1896 if (firsterr)
1897 goto unwind;
1898 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval * HZ);
1899 if (firsterr)
1900 goto unwind;
1901 firsterr = rcu_torture_stall_init();
1902 if (firsterr)
1903 goto unwind;
1904 firsterr = rcu_torture_barrier_init();
1905 if (firsterr)
1906 goto unwind;
1907 if (object_debug)
1908 rcu_test_debug_objects();
1909 if (cbflood_n_burst > 0) {
1910 /* Create the cbflood threads */
1911 ncbflooders = (num_online_cpus() + 3) / 4;
1912 cbflood_task = kcalloc(ncbflooders, sizeof(*cbflood_task),
1913 GFP_KERNEL);
1914 if (!cbflood_task) {
1915 VERBOSE_TOROUT_ERRSTRING("out of memory");
1916 firsterr = -ENOMEM;
1917 goto unwind;
1918 }
1919 for (i = 0; i < ncbflooders; i++) {
1920 firsterr = torture_create_kthread(rcu_torture_cbflood,
1921 NULL,
1922 cbflood_task[i]);
1923 if (firsterr)
1924 goto unwind;
1925 }
1926 }
1927 rcutorture_record_test_transition();
1928 torture_init_end();
1929 return 0;
1930
1931unwind:
1932 torture_init_end();
1933 rcu_torture_cleanup();
1934 return firsterr;
1935}
1936
1937module_init(rcu_torture_init);
1938module_exit(rcu_torture_cleanup);