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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@freedesktop.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
53MODULE_LICENSE("GPL");
54MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@freedesktop.org>");
55
56
57torture_param(int, fqs_duration, 0,
58 "Duration of fqs bursts (us), 0 to disable");
59torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
60torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
61torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
62torture_param(bool, gp_normal, false,
63 "Use normal (non-expedited) GP wait primitives");
64torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
65torture_param(int, n_barrier_cbs, 0,
66 "# of callbacks/kthreads for barrier testing");
67torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
68torture_param(int, nreaders, -1, "Number of RCU reader threads");
69torture_param(int, object_debug, 0,
70 "Enable debug-object double call_rcu() testing");
71torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
72torture_param(int, onoff_interval, 0,
73 "Time between CPU hotplugs (s), 0=disable");
74torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
75torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
76torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
77torture_param(int, stall_cpu_holdoff, 10,
78 "Time to wait before starting stall (s).");
79torture_param(int, stat_interval, 60,
80 "Number of seconds between stats printk()s");
81torture_param(int, stutter, 5, "Number of seconds to run/halt test");
82torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
83torture_param(int, test_boost_duration, 4,
84 "Duration of each boost test, seconds.");
85torture_param(int, test_boost_interval, 7,
86 "Interval between boost tests, seconds.");
87torture_param(bool, test_no_idle_hz, true,
88 "Test support for tickless idle CPUs");
89torture_param(bool, verbose, true,
90 "Enable verbose debugging printk()s");
91
92static char *torture_type = "rcu";
93module_param(torture_type, charp, 0444);
94MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, ...)");
95
96static int nrealreaders;
97static struct task_struct *writer_task;
98static struct task_struct **fakewriter_tasks;
99static struct task_struct **reader_tasks;
100static struct task_struct *stats_task;
101static struct task_struct *fqs_task;
102static struct task_struct *boost_tasks[NR_CPUS];
103static struct task_struct *stall_task;
104static struct task_struct **barrier_cbs_tasks;
105static struct task_struct *barrier_task;
106
107#define RCU_TORTURE_PIPE_LEN 10
108
109struct rcu_torture {
110 struct rcu_head rtort_rcu;
111 int rtort_pipe_count;
112 struct list_head rtort_free;
113 int rtort_mbtest;
114};
115
116static LIST_HEAD(rcu_torture_freelist);
117static struct rcu_torture __rcu *rcu_torture_current;
118static unsigned long rcu_torture_current_version;
119static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
120static DEFINE_SPINLOCK(rcu_torture_lock);
121static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1],
122 rcu_torture_count) = { 0 };
123static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1],
124 rcu_torture_batch) = { 0 };
125static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
126static atomic_t n_rcu_torture_alloc;
127static atomic_t n_rcu_torture_alloc_fail;
128static atomic_t n_rcu_torture_free;
129static atomic_t n_rcu_torture_mberror;
130static atomic_t n_rcu_torture_error;
131static long n_rcu_torture_barrier_error;
132static long n_rcu_torture_boost_ktrerror;
133static long n_rcu_torture_boost_rterror;
134static long n_rcu_torture_boost_failure;
135static long n_rcu_torture_boosts;
136static long n_rcu_torture_timers;
137static long n_barrier_attempts;
138static long n_barrier_successes;
139static struct list_head rcu_torture_removed;
140
141#if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
142#define RCUTORTURE_RUNNABLE_INIT 1
143#else
144#define RCUTORTURE_RUNNABLE_INIT 0
145#endif
146int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT;
147module_param(rcutorture_runnable, int, 0444);
148MODULE_PARM_DESC(rcutorture_runnable, "Start rcutorture at boot");
149
150#if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
151#define rcu_can_boost() 1
152#else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
153#define rcu_can_boost() 0
154#endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
155
156#ifdef CONFIG_RCU_TRACE
157static u64 notrace rcu_trace_clock_local(void)
158{
159 u64 ts = trace_clock_local();
160 unsigned long __maybe_unused ts_rem = do_div(ts, NSEC_PER_USEC);
161 return ts;
162}
163#else /* #ifdef CONFIG_RCU_TRACE */
164static u64 notrace rcu_trace_clock_local(void)
165{
166 return 0ULL;
167}
168#endif /* #else #ifdef CONFIG_RCU_TRACE */
169
170static unsigned long boost_starttime; /* jiffies of next boost test start. */
171DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
172 /* and boost task create/destroy. */
173static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
174static bool barrier_phase; /* Test phase. */
175static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
176static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
177static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
178
179/*
180 * Allocate an element from the rcu_tortures pool.
181 */
182static struct rcu_torture *
183rcu_torture_alloc(void)
184{
185 struct list_head *p;
186
187 spin_lock_bh(&rcu_torture_lock);
188 if (list_empty(&rcu_torture_freelist)) {
189 atomic_inc(&n_rcu_torture_alloc_fail);
190 spin_unlock_bh(&rcu_torture_lock);
191 return NULL;
192 }
193 atomic_inc(&n_rcu_torture_alloc);
194 p = rcu_torture_freelist.next;
195 list_del_init(p);
196 spin_unlock_bh(&rcu_torture_lock);
197 return container_of(p, struct rcu_torture, rtort_free);
198}
199
200/*
201 * Free an element to the rcu_tortures pool.
202 */
203static void
204rcu_torture_free(struct rcu_torture *p)
205{
206 atomic_inc(&n_rcu_torture_free);
207 spin_lock_bh(&rcu_torture_lock);
208 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
209 spin_unlock_bh(&rcu_torture_lock);
210}
211
212/*
213 * Operations vector for selecting different types of tests.
214 */
215
216struct rcu_torture_ops {
217 void (*init)(void);
218 int (*readlock)(void);
219 void (*read_delay)(struct torture_random_state *rrsp);
220 void (*readunlock)(int idx);
221 int (*completed)(void);
222 void (*deferred_free)(struct rcu_torture *p);
223 void (*sync)(void);
224 void (*exp_sync)(void);
225 void (*call)(struct rcu_head *head, void (*func)(struct rcu_head *rcu));
226 void (*cb_barrier)(void);
227 void (*fqs)(void);
228 void (*stats)(char *page);
229 int irq_capable;
230 int can_boost;
231 const char *name;
232};
233
234static struct rcu_torture_ops *cur_ops;
235
236/*
237 * Definitions for rcu torture testing.
238 */
239
240static int rcu_torture_read_lock(void) __acquires(RCU)
241{
242 rcu_read_lock();
243 return 0;
244}
245
246static void rcu_read_delay(struct torture_random_state *rrsp)
247{
248 const unsigned long shortdelay_us = 200;
249 const unsigned long longdelay_ms = 50;
250
251 /* We want a short delay sometimes to make a reader delay the grace
252 * period, and we want a long delay occasionally to trigger
253 * force_quiescent_state. */
254
255 if (!(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms)))
256 mdelay(longdelay_ms);
257 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
258 udelay(shortdelay_us);
259#ifdef CONFIG_PREEMPT
260 if (!preempt_count() &&
261 !(torture_random(rrsp) % (nrealreaders * 20000)))
262 preempt_schedule(); /* No QS if preempt_disable() in effect */
263#endif
264}
265
266static void rcu_torture_read_unlock(int idx) __releases(RCU)
267{
268 rcu_read_unlock();
269}
270
271static int rcu_torture_completed(void)
272{
273 return rcu_batches_completed();
274}
275
276static void
277rcu_torture_cb(struct rcu_head *p)
278{
279 int i;
280 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
281
282 if (torture_must_stop_irq()) {
283 /* Test is ending, just drop callbacks on the floor. */
284 /* The next initialization will pick up the pieces. */
285 return;
286 }
287 i = rp->rtort_pipe_count;
288 if (i > RCU_TORTURE_PIPE_LEN)
289 i = RCU_TORTURE_PIPE_LEN;
290 atomic_inc(&rcu_torture_wcount[i]);
291 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
292 rp->rtort_mbtest = 0;
293 rcu_torture_free(rp);
294 } else {
295 cur_ops->deferred_free(rp);
296 }
297}
298
299static int rcu_no_completed(void)
300{
301 return 0;
302}
303
304static void rcu_torture_deferred_free(struct rcu_torture *p)
305{
306 call_rcu(&p->rtort_rcu, rcu_torture_cb);
307}
308
309static void rcu_sync_torture_init(void)
310{
311 INIT_LIST_HEAD(&rcu_torture_removed);
312}
313
314static struct rcu_torture_ops rcu_ops = {
315 .init = rcu_sync_torture_init,
316 .readlock = rcu_torture_read_lock,
317 .read_delay = rcu_read_delay,
318 .readunlock = rcu_torture_read_unlock,
319 .completed = rcu_torture_completed,
320 .deferred_free = rcu_torture_deferred_free,
321 .sync = synchronize_rcu,
322 .exp_sync = synchronize_rcu_expedited,
323 .call = call_rcu,
324 .cb_barrier = rcu_barrier,
325 .fqs = rcu_force_quiescent_state,
326 .stats = NULL,
327 .irq_capable = 1,
328 .can_boost = rcu_can_boost(),
329 .name = "rcu"
330};
331
332/*
333 * Definitions for rcu_bh torture testing.
334 */
335
336static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
337{
338 rcu_read_lock_bh();
339 return 0;
340}
341
342static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
343{
344 rcu_read_unlock_bh();
345}
346
347static int rcu_bh_torture_completed(void)
348{
349 return rcu_batches_completed_bh();
350}
351
352static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
353{
354 call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
355}
356
357static struct rcu_torture_ops rcu_bh_ops = {
358 .init = rcu_sync_torture_init,
359 .readlock = rcu_bh_torture_read_lock,
360 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
361 .readunlock = rcu_bh_torture_read_unlock,
362 .completed = rcu_bh_torture_completed,
363 .deferred_free = rcu_bh_torture_deferred_free,
364 .sync = synchronize_rcu_bh,
365 .exp_sync = synchronize_rcu_bh_expedited,
366 .call = call_rcu_bh,
367 .cb_barrier = rcu_barrier_bh,
368 .fqs = rcu_bh_force_quiescent_state,
369 .stats = NULL,
370 .irq_capable = 1,
371 .name = "rcu_bh"
372};
373
374/*
375 * Don't even think about trying any of these in real life!!!
376 * The names includes "busted", and they really means it!
377 * The only purpose of these functions is to provide a buggy RCU
378 * implementation to make sure that rcutorture correctly emits
379 * buggy-RCU error messages.
380 */
381static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
382{
383 /* This is a deliberate bug for testing purposes only! */
384 rcu_torture_cb(&p->rtort_rcu);
385}
386
387static void synchronize_rcu_busted(void)
388{
389 /* This is a deliberate bug for testing purposes only! */
390}
391
392static void
393call_rcu_busted(struct rcu_head *head, void (*func)(struct rcu_head *rcu))
394{
395 /* This is a deliberate bug for testing purposes only! */
396 func(head);
397}
398
399static struct rcu_torture_ops rcu_busted_ops = {
400 .init = rcu_sync_torture_init,
401 .readlock = rcu_torture_read_lock,
402 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
403 .readunlock = rcu_torture_read_unlock,
404 .completed = rcu_no_completed,
405 .deferred_free = rcu_busted_torture_deferred_free,
406 .sync = synchronize_rcu_busted,
407 .exp_sync = synchronize_rcu_busted,
408 .call = call_rcu_busted,
409 .cb_barrier = NULL,
410 .fqs = NULL,
411 .stats = NULL,
412 .irq_capable = 1,
413 .name = "rcu_busted"
414};
415
416/*
417 * Definitions for srcu torture testing.
418 */
419
420DEFINE_STATIC_SRCU(srcu_ctl);
421
422static int srcu_torture_read_lock(void) __acquires(&srcu_ctl)
423{
424 return srcu_read_lock(&srcu_ctl);
425}
426
427static void srcu_read_delay(struct torture_random_state *rrsp)
428{
429 long delay;
430 const long uspertick = 1000000 / HZ;
431 const long longdelay = 10;
432
433 /* We want there to be long-running readers, but not all the time. */
434
435 delay = torture_random(rrsp) %
436 (nrealreaders * 2 * longdelay * uspertick);
437 if (!delay)
438 schedule_timeout_interruptible(longdelay);
439 else
440 rcu_read_delay(rrsp);
441}
442
443static void srcu_torture_read_unlock(int idx) __releases(&srcu_ctl)
444{
445 srcu_read_unlock(&srcu_ctl, idx);
446}
447
448static int srcu_torture_completed(void)
449{
450 return srcu_batches_completed(&srcu_ctl);
451}
452
453static void srcu_torture_deferred_free(struct rcu_torture *rp)
454{
455 call_srcu(&srcu_ctl, &rp->rtort_rcu, rcu_torture_cb);
456}
457
458static void srcu_torture_synchronize(void)
459{
460 synchronize_srcu(&srcu_ctl);
461}
462
463static void srcu_torture_call(struct rcu_head *head,
464 void (*func)(struct rcu_head *head))
465{
466 call_srcu(&srcu_ctl, head, func);
467}
468
469static void srcu_torture_barrier(void)
470{
471 srcu_barrier(&srcu_ctl);
472}
473
474static void srcu_torture_stats(char *page)
475{
476 int cpu;
477 int idx = srcu_ctl.completed & 0x1;
478
479 page += sprintf(page, "%s%s per-CPU(idx=%d):",
480 torture_type, TORTURE_FLAG, idx);
481 for_each_possible_cpu(cpu) {
482 page += sprintf(page, " %d(%lu,%lu)", cpu,
483 per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx],
484 per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx]);
485 }
486 sprintf(page, "\n");
487}
488
489static void srcu_torture_synchronize_expedited(void)
490{
491 synchronize_srcu_expedited(&srcu_ctl);
492}
493
494static struct rcu_torture_ops srcu_ops = {
495 .init = rcu_sync_torture_init,
496 .readlock = srcu_torture_read_lock,
497 .read_delay = srcu_read_delay,
498 .readunlock = srcu_torture_read_unlock,
499 .completed = srcu_torture_completed,
500 .deferred_free = srcu_torture_deferred_free,
501 .sync = srcu_torture_synchronize,
502 .exp_sync = srcu_torture_synchronize_expedited,
503 .call = srcu_torture_call,
504 .cb_barrier = srcu_torture_barrier,
505 .stats = srcu_torture_stats,
506 .name = "srcu"
507};
508
509/*
510 * Definitions for sched torture testing.
511 */
512
513static int sched_torture_read_lock(void)
514{
515 preempt_disable();
516 return 0;
517}
518
519static void sched_torture_read_unlock(int idx)
520{
521 preempt_enable();
522}
523
524static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
525{
526 call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
527}
528
529static struct rcu_torture_ops sched_ops = {
530 .init = rcu_sync_torture_init,
531 .readlock = sched_torture_read_lock,
532 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
533 .readunlock = sched_torture_read_unlock,
534 .completed = rcu_no_completed,
535 .deferred_free = rcu_sched_torture_deferred_free,
536 .sync = synchronize_sched,
537 .exp_sync = synchronize_sched_expedited,
538 .call = call_rcu_sched,
539 .cb_barrier = rcu_barrier_sched,
540 .fqs = rcu_sched_force_quiescent_state,
541 .stats = NULL,
542 .irq_capable = 1,
543 .name = "sched"
544};
545
546/*
547 * RCU torture priority-boost testing. Runs one real-time thread per
548 * CPU for moderate bursts, repeatedly registering RCU callbacks and
549 * spinning waiting for them to be invoked. If a given callback takes
550 * too long to be invoked, we assume that priority inversion has occurred.
551 */
552
553struct rcu_boost_inflight {
554 struct rcu_head rcu;
555 int inflight;
556};
557
558static void rcu_torture_boost_cb(struct rcu_head *head)
559{
560 struct rcu_boost_inflight *rbip =
561 container_of(head, struct rcu_boost_inflight, rcu);
562
563 smp_mb(); /* Ensure RCU-core accesses precede clearing ->inflight */
564 rbip->inflight = 0;
565}
566
567static int rcu_torture_boost(void *arg)
568{
569 unsigned long call_rcu_time;
570 unsigned long endtime;
571 unsigned long oldstarttime;
572 struct rcu_boost_inflight rbi = { .inflight = 0 };
573 struct sched_param sp;
574
575 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
576
577 /* Set real-time priority. */
578 sp.sched_priority = 1;
579 if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
580 VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!");
581 n_rcu_torture_boost_rterror++;
582 }
583
584 init_rcu_head_on_stack(&rbi.rcu);
585 /* Each pass through the following loop does one boost-test cycle. */
586 do {
587 /* Wait for the next test interval. */
588 oldstarttime = boost_starttime;
589 while (ULONG_CMP_LT(jiffies, oldstarttime)) {
590 schedule_timeout_interruptible(oldstarttime - jiffies);
591 stutter_wait("rcu_torture_boost");
592 if (torture_must_stop())
593 goto checkwait;
594 }
595
596 /* Do one boost-test interval. */
597 endtime = oldstarttime + test_boost_duration * HZ;
598 call_rcu_time = jiffies;
599 while (ULONG_CMP_LT(jiffies, endtime)) {
600 /* If we don't have a callback in flight, post one. */
601 if (!rbi.inflight) {
602 smp_mb(); /* RCU core before ->inflight = 1. */
603 rbi.inflight = 1;
604 call_rcu(&rbi.rcu, rcu_torture_boost_cb);
605 if (jiffies - call_rcu_time >
606 test_boost_duration * HZ - HZ / 2) {
607 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
608 n_rcu_torture_boost_failure++;
609 }
610 call_rcu_time = jiffies;
611 }
612 cond_resched();
613 stutter_wait("rcu_torture_boost");
614 if (torture_must_stop())
615 goto checkwait;
616 }
617
618 /*
619 * Set the start time of the next test interval.
620 * Yes, this is vulnerable to long delays, but such
621 * delays simply cause a false negative for the next
622 * interval. Besides, we are running at RT priority,
623 * so delays should be relatively rare.
624 */
625 while (oldstarttime == boost_starttime &&
626 !kthread_should_stop()) {
627 if (mutex_trylock(&boost_mutex)) {
628 boost_starttime = jiffies +
629 test_boost_interval * HZ;
630 n_rcu_torture_boosts++;
631 mutex_unlock(&boost_mutex);
632 break;
633 }
634 schedule_timeout_uninterruptible(1);
635 }
636
637 /* Go do the stutter. */
638checkwait: stutter_wait("rcu_torture_boost");
639 } while (!torture_must_stop());
640
641 /* Clean up and exit. */
642 while (!kthread_should_stop() || rbi.inflight) {
643 torture_shutdown_absorb("rcu_torture_boost");
644 schedule_timeout_uninterruptible(1);
645 }
646 smp_mb(); /* order accesses to ->inflight before stack-frame death. */
647 destroy_rcu_head_on_stack(&rbi.rcu);
648 torture_kthread_stopping("rcu_torture_boost");
649 return 0;
650}
651
652/*
653 * RCU torture force-quiescent-state kthread. Repeatedly induces
654 * bursts of calls to force_quiescent_state(), increasing the probability
655 * of occurrence of some important types of race conditions.
656 */
657static int
658rcu_torture_fqs(void *arg)
659{
660 unsigned long fqs_resume_time;
661 int fqs_burst_remaining;
662
663 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
664 do {
665 fqs_resume_time = jiffies + fqs_stutter * HZ;
666 while (ULONG_CMP_LT(jiffies, fqs_resume_time) &&
667 !kthread_should_stop()) {
668 schedule_timeout_interruptible(1);
669 }
670 fqs_burst_remaining = fqs_duration;
671 while (fqs_burst_remaining > 0 &&
672 !kthread_should_stop()) {
673 cur_ops->fqs();
674 udelay(fqs_holdoff);
675 fqs_burst_remaining -= fqs_holdoff;
676 }
677 stutter_wait("rcu_torture_fqs");
678 } while (!torture_must_stop());
679 torture_kthread_stopping("rcu_torture_fqs");
680 return 0;
681}
682
683/*
684 * RCU torture writer kthread. Repeatedly substitutes a new structure
685 * for that pointed to by rcu_torture_current, freeing the old structure
686 * after a series of grace periods (the "pipeline").
687 */
688static int
689rcu_torture_writer(void *arg)
690{
691 bool exp;
692 int i;
693 struct rcu_torture *rp;
694 struct rcu_torture *rp1;
695 struct rcu_torture *old_rp;
696 static DEFINE_TORTURE_RANDOM(rand);
697
698 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
699 set_user_nice(current, MAX_NICE);
700
701 do {
702 schedule_timeout_uninterruptible(1);
703 rp = rcu_torture_alloc();
704 if (rp == NULL)
705 continue;
706 rp->rtort_pipe_count = 0;
707 udelay(torture_random(&rand) & 0x3ff);
708 old_rp = rcu_dereference_check(rcu_torture_current,
709 current == writer_task);
710 rp->rtort_mbtest = 1;
711 rcu_assign_pointer(rcu_torture_current, rp);
712 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
713 if (old_rp) {
714 i = old_rp->rtort_pipe_count;
715 if (i > RCU_TORTURE_PIPE_LEN)
716 i = RCU_TORTURE_PIPE_LEN;
717 atomic_inc(&rcu_torture_wcount[i]);
718 old_rp->rtort_pipe_count++;
719 if (gp_normal == gp_exp)
720 exp = !!(torture_random(&rand) & 0x80);
721 else
722 exp = gp_exp;
723 if (!exp) {
724 cur_ops->deferred_free(old_rp);
725 } else {
726 cur_ops->exp_sync();
727 list_add(&old_rp->rtort_free,
728 &rcu_torture_removed);
729 list_for_each_entry_safe(rp, rp1,
730 &rcu_torture_removed,
731 rtort_free) {
732 i = rp->rtort_pipe_count;
733 if (i > RCU_TORTURE_PIPE_LEN)
734 i = RCU_TORTURE_PIPE_LEN;
735 atomic_inc(&rcu_torture_wcount[i]);
736 if (++rp->rtort_pipe_count >=
737 RCU_TORTURE_PIPE_LEN) {
738 rp->rtort_mbtest = 0;
739 list_del(&rp->rtort_free);
740 rcu_torture_free(rp);
741 }
742 }
743 }
744 }
745 rcutorture_record_progress(++rcu_torture_current_version);
746 stutter_wait("rcu_torture_writer");
747 } while (!torture_must_stop());
748 torture_kthread_stopping("rcu_torture_writer");
749 return 0;
750}
751
752/*
753 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
754 * delay between calls.
755 */
756static int
757rcu_torture_fakewriter(void *arg)
758{
759 DEFINE_TORTURE_RANDOM(rand);
760
761 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
762 set_user_nice(current, MAX_NICE);
763
764 do {
765 schedule_timeout_uninterruptible(1 + torture_random(&rand)%10);
766 udelay(torture_random(&rand) & 0x3ff);
767 if (cur_ops->cb_barrier != NULL &&
768 torture_random(&rand) % (nfakewriters * 8) == 0) {
769 cur_ops->cb_barrier();
770 } else if (gp_normal == gp_exp) {
771 if (torture_random(&rand) & 0x80)
772 cur_ops->sync();
773 else
774 cur_ops->exp_sync();
775 } else if (gp_normal) {
776 cur_ops->sync();
777 } else {
778 cur_ops->exp_sync();
779 }
780 stutter_wait("rcu_torture_fakewriter");
781 } while (!torture_must_stop());
782
783 torture_kthread_stopping("rcu_torture_fakewriter");
784 return 0;
785}
786
787void rcutorture_trace_dump(void)
788{
789 static atomic_t beenhere = ATOMIC_INIT(0);
790
791 if (atomic_read(&beenhere))
792 return;
793 if (atomic_xchg(&beenhere, 1) != 0)
794 return;
795 ftrace_dump(DUMP_ALL);
796}
797
798/*
799 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
800 * incrementing the corresponding element of the pipeline array. The
801 * counter in the element should never be greater than 1, otherwise, the
802 * RCU implementation is broken.
803 */
804static void rcu_torture_timer(unsigned long unused)
805{
806 int idx;
807 int completed;
808 int completed_end;
809 static DEFINE_TORTURE_RANDOM(rand);
810 static DEFINE_SPINLOCK(rand_lock);
811 struct rcu_torture *p;
812 int pipe_count;
813 unsigned long long ts;
814
815 idx = cur_ops->readlock();
816 completed = cur_ops->completed();
817 ts = rcu_trace_clock_local();
818 p = rcu_dereference_check(rcu_torture_current,
819 rcu_read_lock_bh_held() ||
820 rcu_read_lock_sched_held() ||
821 srcu_read_lock_held(&srcu_ctl));
822 if (p == NULL) {
823 /* Leave because rcu_torture_writer is not yet underway */
824 cur_ops->readunlock(idx);
825 return;
826 }
827 if (p->rtort_mbtest == 0)
828 atomic_inc(&n_rcu_torture_mberror);
829 spin_lock(&rand_lock);
830 cur_ops->read_delay(&rand);
831 n_rcu_torture_timers++;
832 spin_unlock(&rand_lock);
833 preempt_disable();
834 pipe_count = p->rtort_pipe_count;
835 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
836 /* Should not happen, but... */
837 pipe_count = RCU_TORTURE_PIPE_LEN;
838 }
839 completed_end = cur_ops->completed();
840 if (pipe_count > 1) {
841 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, ts,
842 completed, completed_end);
843 rcutorture_trace_dump();
844 }
845 __this_cpu_inc(rcu_torture_count[pipe_count]);
846 completed = completed_end - completed;
847 if (completed > RCU_TORTURE_PIPE_LEN) {
848 /* Should not happen, but... */
849 completed = RCU_TORTURE_PIPE_LEN;
850 }
851 __this_cpu_inc(rcu_torture_batch[completed]);
852 preempt_enable();
853 cur_ops->readunlock(idx);
854}
855
856/*
857 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
858 * incrementing the corresponding element of the pipeline array. The
859 * counter in the element should never be greater than 1, otherwise, the
860 * RCU implementation is broken.
861 */
862static int
863rcu_torture_reader(void *arg)
864{
865 int completed;
866 int completed_end;
867 int idx;
868 DEFINE_TORTURE_RANDOM(rand);
869 struct rcu_torture *p;
870 int pipe_count;
871 struct timer_list t;
872 unsigned long long ts;
873
874 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
875 set_user_nice(current, MAX_NICE);
876 if (irqreader && cur_ops->irq_capable)
877 setup_timer_on_stack(&t, rcu_torture_timer, 0);
878
879 do {
880 if (irqreader && cur_ops->irq_capable) {
881 if (!timer_pending(&t))
882 mod_timer(&t, jiffies + 1);
883 }
884 idx = cur_ops->readlock();
885 completed = cur_ops->completed();
886 ts = rcu_trace_clock_local();
887 p = rcu_dereference_check(rcu_torture_current,
888 rcu_read_lock_bh_held() ||
889 rcu_read_lock_sched_held() ||
890 srcu_read_lock_held(&srcu_ctl));
891 if (p == NULL) {
892 /* Wait for rcu_torture_writer to get underway */
893 cur_ops->readunlock(idx);
894 schedule_timeout_interruptible(HZ);
895 continue;
896 }
897 if (p->rtort_mbtest == 0)
898 atomic_inc(&n_rcu_torture_mberror);
899 cur_ops->read_delay(&rand);
900 preempt_disable();
901 pipe_count = p->rtort_pipe_count;
902 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
903 /* Should not happen, but... */
904 pipe_count = RCU_TORTURE_PIPE_LEN;
905 }
906 completed_end = cur_ops->completed();
907 if (pipe_count > 1) {
908 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
909 ts, completed, completed_end);
910 rcutorture_trace_dump();
911 }
912 __this_cpu_inc(rcu_torture_count[pipe_count]);
913 completed = completed_end - completed;
914 if (completed > RCU_TORTURE_PIPE_LEN) {
915 /* Should not happen, but... */
916 completed = RCU_TORTURE_PIPE_LEN;
917 }
918 __this_cpu_inc(rcu_torture_batch[completed]);
919 preempt_enable();
920 cur_ops->readunlock(idx);
921 schedule();
922 stutter_wait("rcu_torture_reader");
923 } while (!torture_must_stop());
924 if (irqreader && cur_ops->irq_capable)
925 del_timer_sync(&t);
926 torture_kthread_stopping("rcu_torture_reader");
927 return 0;
928}
929
930/*
931 * Create an RCU-torture statistics message in the specified buffer.
932 */
933static void
934rcu_torture_printk(char *page)
935{
936 int cpu;
937 int i;
938 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
939 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
940
941 for_each_possible_cpu(cpu) {
942 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
943 pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
944 batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
945 }
946 }
947 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
948 if (pipesummary[i] != 0)
949 break;
950 }
951 page += sprintf(page, "%s%s ", torture_type, TORTURE_FLAG);
952 page += sprintf(page,
953 "rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
954 rcu_torture_current,
955 rcu_torture_current_version,
956 list_empty(&rcu_torture_freelist),
957 atomic_read(&n_rcu_torture_alloc),
958 atomic_read(&n_rcu_torture_alloc_fail),
959 atomic_read(&n_rcu_torture_free));
960 page += sprintf(page, "rtmbe: %d rtbke: %ld rtbre: %ld ",
961 atomic_read(&n_rcu_torture_mberror),
962 n_rcu_torture_boost_ktrerror,
963 n_rcu_torture_boost_rterror);
964 page += sprintf(page, "rtbf: %ld rtb: %ld nt: %ld ",
965 n_rcu_torture_boost_failure,
966 n_rcu_torture_boosts,
967 n_rcu_torture_timers);
968 page = torture_onoff_stats(page);
969 page += sprintf(page, "barrier: %ld/%ld:%ld",
970 n_barrier_successes,
971 n_barrier_attempts,
972 n_rcu_torture_barrier_error);
973 page += sprintf(page, "\n%s%s ", torture_type, TORTURE_FLAG);
974 if (atomic_read(&n_rcu_torture_mberror) != 0 ||
975 n_rcu_torture_barrier_error != 0 ||
976 n_rcu_torture_boost_ktrerror != 0 ||
977 n_rcu_torture_boost_rterror != 0 ||
978 n_rcu_torture_boost_failure != 0 ||
979 i > 1) {
980 page += sprintf(page, "!!! ");
981 atomic_inc(&n_rcu_torture_error);
982 WARN_ON_ONCE(1);
983 }
984 page += sprintf(page, "Reader Pipe: ");
985 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
986 page += sprintf(page, " %ld", pipesummary[i]);
987 page += sprintf(page, "\n%s%s ", torture_type, TORTURE_FLAG);
988 page += sprintf(page, "Reader Batch: ");
989 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
990 page += sprintf(page, " %ld", batchsummary[i]);
991 page += sprintf(page, "\n%s%s ", torture_type, TORTURE_FLAG);
992 page += sprintf(page, "Free-Block Circulation: ");
993 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
994 page += sprintf(page, " %d",
995 atomic_read(&rcu_torture_wcount[i]));
996 }
997 page += sprintf(page, "\n");
998 if (cur_ops->stats)
999 cur_ops->stats(page);
1000}
1001
1002/*
1003 * Print torture statistics. Caller must ensure that there is only
1004 * one call to this function at a given time!!! This is normally
1005 * accomplished by relying on the module system to only have one copy
1006 * of the module loaded, and then by giving the rcu_torture_stats
1007 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1008 * thread is not running).
1009 */
1010static void
1011rcu_torture_stats_print(void)
1012{
1013 int size = nr_cpu_ids * 200 + 8192;
1014 char *buf;
1015
1016 buf = kmalloc(size, GFP_KERNEL);
1017 if (!buf) {
1018 pr_err("rcu-torture: Out of memory, need: %d", size);
1019 return;
1020 }
1021 rcu_torture_printk(buf);
1022 pr_alert("%s", buf);
1023 kfree(buf);
1024}
1025
1026/*
1027 * Periodically prints torture statistics, if periodic statistics printing
1028 * was specified via the stat_interval module parameter.
1029 */
1030static int
1031rcu_torture_stats(void *arg)
1032{
1033 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1034 do {
1035 schedule_timeout_interruptible(stat_interval * HZ);
1036 rcu_torture_stats_print();
1037 torture_shutdown_absorb("rcu_torture_stats");
1038 } while (!torture_must_stop());
1039 torture_kthread_stopping("rcu_torture_stats");
1040 return 0;
1041}
1042
1043static inline void
1044rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1045{
1046 pr_alert("%s" TORTURE_FLAG
1047 "--- %s: nreaders=%d nfakewriters=%d "
1048 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1049 "shuffle_interval=%d stutter=%d irqreader=%d "
1050 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1051 "test_boost=%d/%d test_boost_interval=%d "
1052 "test_boost_duration=%d shutdown_secs=%d "
1053 "stall_cpu=%d stall_cpu_holdoff=%d "
1054 "n_barrier_cbs=%d "
1055 "onoff_interval=%d onoff_holdoff=%d\n",
1056 torture_type, tag, nrealreaders, nfakewriters,
1057 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1058 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1059 test_boost, cur_ops->can_boost,
1060 test_boost_interval, test_boost_duration, shutdown_secs,
1061 stall_cpu, stall_cpu_holdoff,
1062 n_barrier_cbs,
1063 onoff_interval, onoff_holdoff);
1064}
1065
1066static void rcutorture_booster_cleanup(int cpu)
1067{
1068 struct task_struct *t;
1069
1070 if (boost_tasks[cpu] == NULL)
1071 return;
1072 mutex_lock(&boost_mutex);
1073 t = boost_tasks[cpu];
1074 boost_tasks[cpu] = NULL;
1075 mutex_unlock(&boost_mutex);
1076
1077 /* This must be outside of the mutex, otherwise deadlock! */
1078 torture_stop_kthread(rcu_torture_boost, t);
1079}
1080
1081static int rcutorture_booster_init(int cpu)
1082{
1083 int retval;
1084
1085 if (boost_tasks[cpu] != NULL)
1086 return 0; /* Already created, nothing more to do. */
1087
1088 /* Don't allow time recalculation while creating a new task. */
1089 mutex_lock(&boost_mutex);
1090 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
1091 boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
1092 cpu_to_node(cpu),
1093 "rcu_torture_boost");
1094 if (IS_ERR(boost_tasks[cpu])) {
1095 retval = PTR_ERR(boost_tasks[cpu]);
1096 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
1097 n_rcu_torture_boost_ktrerror++;
1098 boost_tasks[cpu] = NULL;
1099 mutex_unlock(&boost_mutex);
1100 return retval;
1101 }
1102 kthread_bind(boost_tasks[cpu], cpu);
1103 wake_up_process(boost_tasks[cpu]);
1104 mutex_unlock(&boost_mutex);
1105 return 0;
1106}
1107
1108/*
1109 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
1110 * induces a CPU stall for the time specified by stall_cpu.
1111 */
1112static int rcu_torture_stall(void *args)
1113{
1114 unsigned long stop_at;
1115
1116 VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
1117 if (stall_cpu_holdoff > 0) {
1118 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
1119 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
1120 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
1121 }
1122 if (!kthread_should_stop()) {
1123 stop_at = get_seconds() + stall_cpu;
1124 /* RCU CPU stall is expected behavior in following code. */
1125 pr_alert("rcu_torture_stall start.\n");
1126 rcu_read_lock();
1127 preempt_disable();
1128 while (ULONG_CMP_LT(get_seconds(), stop_at))
1129 continue; /* Induce RCU CPU stall warning. */
1130 preempt_enable();
1131 rcu_read_unlock();
1132 pr_alert("rcu_torture_stall end.\n");
1133 }
1134 torture_shutdown_absorb("rcu_torture_stall");
1135 while (!kthread_should_stop())
1136 schedule_timeout_interruptible(10 * HZ);
1137 return 0;
1138}
1139
1140/* Spawn CPU-stall kthread, if stall_cpu specified. */
1141static int __init rcu_torture_stall_init(void)
1142{
1143 if (stall_cpu <= 0)
1144 return 0;
1145 return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
1146}
1147
1148/* Callback function for RCU barrier testing. */
1149void rcu_torture_barrier_cbf(struct rcu_head *rcu)
1150{
1151 atomic_inc(&barrier_cbs_invoked);
1152}
1153
1154/* kthread function to register callbacks used to test RCU barriers. */
1155static int rcu_torture_barrier_cbs(void *arg)
1156{
1157 long myid = (long)arg;
1158 bool lastphase = 0;
1159 bool newphase;
1160 struct rcu_head rcu;
1161
1162 init_rcu_head_on_stack(&rcu);
1163 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
1164 set_user_nice(current, MAX_NICE);
1165 do {
1166 wait_event(barrier_cbs_wq[myid],
1167 (newphase =
1168 ACCESS_ONCE(barrier_phase)) != lastphase ||
1169 torture_must_stop());
1170 lastphase = newphase;
1171 smp_mb(); /* ensure barrier_phase load before ->call(). */
1172 if (torture_must_stop())
1173 break;
1174 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
1175 if (atomic_dec_and_test(&barrier_cbs_count))
1176 wake_up(&barrier_wq);
1177 } while (!torture_must_stop());
1178 cur_ops->cb_barrier();
1179 destroy_rcu_head_on_stack(&rcu);
1180 torture_kthread_stopping("rcu_torture_barrier_cbs");
1181 return 0;
1182}
1183
1184/* kthread function to drive and coordinate RCU barrier testing. */
1185static int rcu_torture_barrier(void *arg)
1186{
1187 int i;
1188
1189 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
1190 do {
1191 atomic_set(&barrier_cbs_invoked, 0);
1192 atomic_set(&barrier_cbs_count, n_barrier_cbs);
1193 smp_mb(); /* Ensure barrier_phase after prior assignments. */
1194 barrier_phase = !barrier_phase;
1195 for (i = 0; i < n_barrier_cbs; i++)
1196 wake_up(&barrier_cbs_wq[i]);
1197 wait_event(barrier_wq,
1198 atomic_read(&barrier_cbs_count) == 0 ||
1199 torture_must_stop());
1200 if (torture_must_stop())
1201 break;
1202 n_barrier_attempts++;
1203 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
1204 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
1205 n_rcu_torture_barrier_error++;
1206 WARN_ON_ONCE(1);
1207 }
1208 n_barrier_successes++;
1209 schedule_timeout_interruptible(HZ / 10);
1210 } while (!torture_must_stop());
1211 torture_kthread_stopping("rcu_torture_barrier");
1212 return 0;
1213}
1214
1215/* Initialize RCU barrier testing. */
1216static int rcu_torture_barrier_init(void)
1217{
1218 int i;
1219 int ret;
1220
1221 if (n_barrier_cbs == 0)
1222 return 0;
1223 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
1224 pr_alert("%s" TORTURE_FLAG
1225 " Call or barrier ops missing for %s,\n",
1226 torture_type, cur_ops->name);
1227 pr_alert("%s" TORTURE_FLAG
1228 " RCU barrier testing omitted from run.\n",
1229 torture_type);
1230 return 0;
1231 }
1232 atomic_set(&barrier_cbs_count, 0);
1233 atomic_set(&barrier_cbs_invoked, 0);
1234 barrier_cbs_tasks =
1235 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_tasks[0]),
1236 GFP_KERNEL);
1237 barrier_cbs_wq =
1238 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_wq[0]),
1239 GFP_KERNEL);
1240 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
1241 return -ENOMEM;
1242 for (i = 0; i < n_barrier_cbs; i++) {
1243 init_waitqueue_head(&barrier_cbs_wq[i]);
1244 ret = torture_create_kthread(rcu_torture_barrier_cbs,
1245 (void *)(long)i,
1246 barrier_cbs_tasks[i]);
1247 if (ret)
1248 return ret;
1249 }
1250 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
1251}
1252
1253/* Clean up after RCU barrier testing. */
1254static void rcu_torture_barrier_cleanup(void)
1255{
1256 int i;
1257
1258 torture_stop_kthread(rcu_torture_barrier, barrier_task);
1259 if (barrier_cbs_tasks != NULL) {
1260 for (i = 0; i < n_barrier_cbs; i++)
1261 torture_stop_kthread(rcu_torture_barrier_cbs,
1262 barrier_cbs_tasks[i]);
1263 kfree(barrier_cbs_tasks);
1264 barrier_cbs_tasks = NULL;
1265 }
1266 if (barrier_cbs_wq != NULL) {
1267 kfree(barrier_cbs_wq);
1268 barrier_cbs_wq = NULL;
1269 }
1270}
1271
1272static int rcutorture_cpu_notify(struct notifier_block *self,
1273 unsigned long action, void *hcpu)
1274{
1275 long cpu = (long)hcpu;
1276
1277 switch (action) {
1278 case CPU_ONLINE:
1279 case CPU_DOWN_FAILED:
1280 (void)rcutorture_booster_init(cpu);
1281 break;
1282 case CPU_DOWN_PREPARE:
1283 rcutorture_booster_cleanup(cpu);
1284 break;
1285 default:
1286 break;
1287 }
1288 return NOTIFY_OK;
1289}
1290
1291static struct notifier_block rcutorture_cpu_nb = {
1292 .notifier_call = rcutorture_cpu_notify,
1293};
1294
1295static void
1296rcu_torture_cleanup(void)
1297{
1298 int i;
1299
1300 rcutorture_record_test_transition();
1301 if (torture_cleanup()) {
1302 if (cur_ops->cb_barrier != NULL)
1303 cur_ops->cb_barrier();
1304 return;
1305 }
1306
1307 rcu_torture_barrier_cleanup();
1308 torture_stop_kthread(rcu_torture_stall, stall_task);
1309 torture_stop_kthread(rcu_torture_writer, writer_task);
1310
1311 if (reader_tasks) {
1312 for (i = 0; i < nrealreaders; i++)
1313 torture_stop_kthread(rcu_torture_reader,
1314 reader_tasks[i]);
1315 kfree(reader_tasks);
1316 }
1317 rcu_torture_current = NULL;
1318
1319 if (fakewriter_tasks) {
1320 for (i = 0; i < nfakewriters; i++) {
1321 torture_stop_kthread(rcu_torture_fakewriter,
1322 fakewriter_tasks[i]);
1323 }
1324 kfree(fakewriter_tasks);
1325 fakewriter_tasks = NULL;
1326 }
1327
1328 torture_stop_kthread(rcu_torture_stats, stats_task);
1329 torture_stop_kthread(rcu_torture_fqs, fqs_task);
1330 if ((test_boost == 1 && cur_ops->can_boost) ||
1331 test_boost == 2) {
1332 unregister_cpu_notifier(&rcutorture_cpu_nb);
1333 for_each_possible_cpu(i)
1334 rcutorture_booster_cleanup(i);
1335 }
1336
1337 /* Wait for all RCU callbacks to fire. */
1338
1339 if (cur_ops->cb_barrier != NULL)
1340 cur_ops->cb_barrier();
1341
1342 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
1343
1344 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
1345 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
1346 else if (torture_onoff_failures())
1347 rcu_torture_print_module_parms(cur_ops,
1348 "End of test: RCU_HOTPLUG");
1349 else
1350 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
1351}
1352
1353#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1354static void rcu_torture_leak_cb(struct rcu_head *rhp)
1355{
1356}
1357
1358static void rcu_torture_err_cb(struct rcu_head *rhp)
1359{
1360 /*
1361 * This -might- happen due to race conditions, but is unlikely.
1362 * The scenario that leads to this happening is that the
1363 * first of the pair of duplicate callbacks is queued,
1364 * someone else starts a grace period that includes that
1365 * callback, then the second of the pair must wait for the
1366 * next grace period. Unlikely, but can happen. If it
1367 * does happen, the debug-objects subsystem won't have splatted.
1368 */
1369 pr_alert("rcutorture: duplicated callback was invoked.\n");
1370}
1371#endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1372
1373/*
1374 * Verify that double-free causes debug-objects to complain, but only
1375 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
1376 * cannot be carried out.
1377 */
1378static void rcu_test_debug_objects(void)
1379{
1380#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1381 struct rcu_head rh1;
1382 struct rcu_head rh2;
1383
1384 init_rcu_head_on_stack(&rh1);
1385 init_rcu_head_on_stack(&rh2);
1386 pr_alert("rcutorture: WARN: Duplicate call_rcu() test starting.\n");
1387
1388 /* Try to queue the rh2 pair of callbacks for the same grace period. */
1389 preempt_disable(); /* Prevent preemption from interrupting test. */
1390 rcu_read_lock(); /* Make it impossible to finish a grace period. */
1391 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
1392 local_irq_disable(); /* Make it harder to start a new grace period. */
1393 call_rcu(&rh2, rcu_torture_leak_cb);
1394 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
1395 local_irq_enable();
1396 rcu_read_unlock();
1397 preempt_enable();
1398
1399 /* Wait for them all to get done so we can safely return. */
1400 rcu_barrier();
1401 pr_alert("rcutorture: WARN: Duplicate call_rcu() test complete.\n");
1402 destroy_rcu_head_on_stack(&rh1);
1403 destroy_rcu_head_on_stack(&rh2);
1404#else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1405 pr_alert("rcutorture: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n");
1406#endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1407}
1408
1409static int __init
1410rcu_torture_init(void)
1411{
1412 int i;
1413 int cpu;
1414 int firsterr = 0;
1415 static struct rcu_torture_ops *torture_ops[] = {
1416 &rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &sched_ops,
1417 };
1418
1419 torture_init_begin(torture_type, verbose, &rcutorture_runnable);
1420
1421 /* Process args and tell the world that the torturer is on the job. */
1422 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1423 cur_ops = torture_ops[i];
1424 if (strcmp(torture_type, cur_ops->name) == 0)
1425 break;
1426 }
1427 if (i == ARRAY_SIZE(torture_ops)) {
1428 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
1429 torture_type);
1430 pr_alert("rcu-torture types:");
1431 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1432 pr_alert(" %s", torture_ops[i]->name);
1433 pr_alert("\n");
1434 torture_init_end();
1435 return -EINVAL;
1436 }
1437 if (cur_ops->fqs == NULL && fqs_duration != 0) {
1438 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
1439 fqs_duration = 0;
1440 }
1441 if (cur_ops->init)
1442 cur_ops->init(); /* no "goto unwind" prior to this point!!! */
1443
1444 if (nreaders >= 0)
1445 nrealreaders = nreaders;
1446 else
1447 nrealreaders = 2 * num_online_cpus();
1448 rcu_torture_print_module_parms(cur_ops, "Start of test");
1449
1450 /* Set up the freelist. */
1451
1452 INIT_LIST_HEAD(&rcu_torture_freelist);
1453 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1454 rcu_tortures[i].rtort_mbtest = 0;
1455 list_add_tail(&rcu_tortures[i].rtort_free,
1456 &rcu_torture_freelist);
1457 }
1458
1459 /* Initialize the statistics so that each run gets its own numbers. */
1460
1461 rcu_torture_current = NULL;
1462 rcu_torture_current_version = 0;
1463 atomic_set(&n_rcu_torture_alloc, 0);
1464 atomic_set(&n_rcu_torture_alloc_fail, 0);
1465 atomic_set(&n_rcu_torture_free, 0);
1466 atomic_set(&n_rcu_torture_mberror, 0);
1467 atomic_set(&n_rcu_torture_error, 0);
1468 n_rcu_torture_barrier_error = 0;
1469 n_rcu_torture_boost_ktrerror = 0;
1470 n_rcu_torture_boost_rterror = 0;
1471 n_rcu_torture_boost_failure = 0;
1472 n_rcu_torture_boosts = 0;
1473 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1474 atomic_set(&rcu_torture_wcount[i], 0);
1475 for_each_possible_cpu(cpu) {
1476 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1477 per_cpu(rcu_torture_count, cpu)[i] = 0;
1478 per_cpu(rcu_torture_batch, cpu)[i] = 0;
1479 }
1480 }
1481
1482 /* Start up the kthreads. */
1483
1484 firsterr = torture_create_kthread(rcu_torture_writer, NULL,
1485 writer_task);
1486 if (firsterr)
1487 goto unwind;
1488 fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]),
1489 GFP_KERNEL);
1490 if (fakewriter_tasks == NULL) {
1491 VERBOSE_TOROUT_ERRSTRING("out of memory");
1492 firsterr = -ENOMEM;
1493 goto unwind;
1494 }
1495 for (i = 0; i < nfakewriters; i++) {
1496 firsterr = torture_create_kthread(rcu_torture_fakewriter,
1497 NULL, fakewriter_tasks[i]);
1498 if (firsterr)
1499 goto unwind;
1500 }
1501 reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
1502 GFP_KERNEL);
1503 if (reader_tasks == NULL) {
1504 VERBOSE_TOROUT_ERRSTRING("out of memory");
1505 firsterr = -ENOMEM;
1506 goto unwind;
1507 }
1508 for (i = 0; i < nrealreaders; i++) {
1509 firsterr = torture_create_kthread(rcu_torture_reader, NULL,
1510 reader_tasks[i]);
1511 if (firsterr)
1512 goto unwind;
1513 }
1514 if (stat_interval > 0) {
1515 firsterr = torture_create_kthread(rcu_torture_stats, NULL,
1516 stats_task);
1517 if (firsterr)
1518 goto unwind;
1519 }
1520 if (test_no_idle_hz) {
1521 firsterr = torture_shuffle_init(shuffle_interval * HZ);
1522 if (firsterr)
1523 goto unwind;
1524 }
1525 if (stutter < 0)
1526 stutter = 0;
1527 if (stutter) {
1528 firsterr = torture_stutter_init(stutter * HZ);
1529 if (firsterr)
1530 goto unwind;
1531 }
1532 if (fqs_duration < 0)
1533 fqs_duration = 0;
1534 if (fqs_duration) {
1535 /* Create the fqs thread */
1536 torture_create_kthread(rcu_torture_fqs, NULL, fqs_task);
1537 if (firsterr)
1538 goto unwind;
1539 }
1540 if (test_boost_interval < 1)
1541 test_boost_interval = 1;
1542 if (test_boost_duration < 2)
1543 test_boost_duration = 2;
1544 if ((test_boost == 1 && cur_ops->can_boost) ||
1545 test_boost == 2) {
1546
1547 boost_starttime = jiffies + test_boost_interval * HZ;
1548 register_cpu_notifier(&rcutorture_cpu_nb);
1549 for_each_possible_cpu(i) {
1550 if (cpu_is_offline(i))
1551 continue; /* Heuristic: CPU can go offline. */
1552 firsterr = rcutorture_booster_init(i);
1553 if (firsterr)
1554 goto unwind;
1555 }
1556 }
1557 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
1558 if (firsterr)
1559 goto unwind;
1560 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval * HZ);
1561 if (firsterr)
1562 goto unwind;
1563 firsterr = rcu_torture_stall_init();
1564 if (firsterr)
1565 goto unwind;
1566 firsterr = rcu_torture_barrier_init();
1567 if (firsterr)
1568 goto unwind;
1569 if (object_debug)
1570 rcu_test_debug_objects();
1571 rcutorture_record_test_transition();
1572 torture_init_end();
1573 return 0;
1574
1575unwind:
1576 torture_init_end();
1577 rcu_torture_cleanup();
1578 return firsterr;
1579}
1580
1581module_init(rcu_torture_init);
1582module_exit(rcu_torture_cleanup);
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Read-Copy Update module-based torture test facility
4 *
5 * Copyright (C) IBM Corporation, 2005, 2006
6 *
7 * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
8 * Josh Triplett <josh@joshtriplett.org>
9 *
10 * See also: Documentation/RCU/torture.rst
11 */
12
13#define pr_fmt(fmt) fmt
14
15#include <linux/types.h>
16#include <linux/kernel.h>
17#include <linux/init.h>
18#include <linux/module.h>
19#include <linux/kthread.h>
20#include <linux/err.h>
21#include <linux/spinlock.h>
22#include <linux/smp.h>
23#include <linux/rcupdate_wait.h>
24#include <linux/interrupt.h>
25#include <linux/sched/signal.h>
26#include <uapi/linux/sched/types.h>
27#include <linux/atomic.h>
28#include <linux/bitops.h>
29#include <linux/completion.h>
30#include <linux/moduleparam.h>
31#include <linux/percpu.h>
32#include <linux/notifier.h>
33#include <linux/reboot.h>
34#include <linux/freezer.h>
35#include <linux/cpu.h>
36#include <linux/delay.h>
37#include <linux/stat.h>
38#include <linux/srcu.h>
39#include <linux/slab.h>
40#include <linux/trace_clock.h>
41#include <asm/byteorder.h>
42#include <linux/torture.h>
43#include <linux/vmalloc.h>
44#include <linux/sched/debug.h>
45#include <linux/sched/sysctl.h>
46#include <linux/oom.h>
47#include <linux/tick.h>
48#include <linux/rcupdate_trace.h>
49
50#include "rcu.h"
51
52MODULE_LICENSE("GPL");
53MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
54
55/* Bits for ->extendables field, extendables param, and related definitions. */
56#define RCUTORTURE_RDR_SHIFT 8 /* Put SRCU index in upper bits. */
57#define RCUTORTURE_RDR_MASK ((1 << RCUTORTURE_RDR_SHIFT) - 1)
58#define RCUTORTURE_RDR_BH 0x01 /* Extend readers by disabling bh. */
59#define RCUTORTURE_RDR_IRQ 0x02 /* ... disabling interrupts. */
60#define RCUTORTURE_RDR_PREEMPT 0x04 /* ... disabling preemption. */
61#define RCUTORTURE_RDR_RBH 0x08 /* ... rcu_read_lock_bh(). */
62#define RCUTORTURE_RDR_SCHED 0x10 /* ... rcu_read_lock_sched(). */
63#define RCUTORTURE_RDR_RCU 0x20 /* ... entering another RCU reader. */
64#define RCUTORTURE_RDR_NBITS 6 /* Number of bits defined above. */
65#define RCUTORTURE_MAX_EXTEND \
66 (RCUTORTURE_RDR_BH | RCUTORTURE_RDR_IRQ | RCUTORTURE_RDR_PREEMPT | \
67 RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED)
68#define RCUTORTURE_RDR_MAX_LOOPS 0x7 /* Maximum reader extensions. */
69 /* Must be power of two minus one. */
70#define RCUTORTURE_RDR_MAX_SEGS (RCUTORTURE_RDR_MAX_LOOPS + 3)
71
72torture_param(int, extendables, RCUTORTURE_MAX_EXTEND,
73 "Extend readers by disabling bh (1), irqs (2), or preempt (4)");
74torture_param(int, fqs_duration, 0,
75 "Duration of fqs bursts (us), 0 to disable");
76torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
77torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
78torture_param(bool, fwd_progress, 1, "Test grace-period forward progress");
79torture_param(int, fwd_progress_div, 4, "Fraction of CPU stall to wait");
80torture_param(int, fwd_progress_holdoff, 60,
81 "Time between forward-progress tests (s)");
82torture_param(bool, fwd_progress_need_resched, 1,
83 "Hide cond_resched() behind need_resched()");
84torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
85torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
86torture_param(bool, gp_normal, false,
87 "Use normal (non-expedited) GP wait primitives");
88torture_param(bool, gp_poll, false, "Use polling GP wait primitives");
89torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
90torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
91torture_param(int, leakpointer, 0, "Leak pointer dereferences from readers");
92torture_param(int, n_barrier_cbs, 0,
93 "# of callbacks/kthreads for barrier testing");
94torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
95torture_param(int, nreaders, -1, "Number of RCU reader threads");
96torture_param(int, object_debug, 0,
97 "Enable debug-object double call_rcu() testing");
98torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
99torture_param(int, onoff_interval, 0,
100 "Time between CPU hotplugs (jiffies), 0=disable");
101torture_param(int, nocbs_nthreads, 0, "Number of NOCB toggle threads, 0 to disable");
102torture_param(int, nocbs_toggle, 1000, "Time between toggling nocb state (ms)");
103torture_param(int, read_exit_delay, 13,
104 "Delay between read-then-exit episodes (s)");
105torture_param(int, read_exit_burst, 16,
106 "# of read-then-exit bursts per episode, zero to disable");
107torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
108torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
109torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
110torture_param(int, stall_cpu_holdoff, 10,
111 "Time to wait before starting stall (s).");
112torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling.");
113torture_param(int, stall_cpu_block, 0, "Sleep while stalling.");
114torture_param(int, stall_gp_kthread, 0,
115 "Grace-period kthread stall duration (s).");
116torture_param(int, stat_interval, 60,
117 "Number of seconds between stats printk()s");
118torture_param(int, stutter, 5, "Number of seconds to run/halt test");
119torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
120torture_param(int, test_boost_duration, 4,
121 "Duration of each boost test, seconds.");
122torture_param(int, test_boost_interval, 7,
123 "Interval between boost tests, seconds.");
124torture_param(bool, test_no_idle_hz, true,
125 "Test support for tickless idle CPUs");
126torture_param(int, verbose, 1,
127 "Enable verbose debugging printk()s");
128
129static char *torture_type = "rcu";
130module_param(torture_type, charp, 0444);
131MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, srcu, ...)");
132
133static int nrealnocbers;
134static int nrealreaders;
135static struct task_struct *writer_task;
136static struct task_struct **fakewriter_tasks;
137static struct task_struct **reader_tasks;
138static struct task_struct **nocb_tasks;
139static struct task_struct *stats_task;
140static struct task_struct *fqs_task;
141static struct task_struct *boost_tasks[NR_CPUS];
142static struct task_struct *stall_task;
143static struct task_struct *fwd_prog_task;
144static struct task_struct **barrier_cbs_tasks;
145static struct task_struct *barrier_task;
146static struct task_struct *read_exit_task;
147
148#define RCU_TORTURE_PIPE_LEN 10
149
150// Mailbox-like structure to check RCU global memory ordering.
151struct rcu_torture_reader_check {
152 unsigned long rtc_myloops;
153 int rtc_chkrdr;
154 unsigned long rtc_chkloops;
155 int rtc_ready;
156 struct rcu_torture_reader_check *rtc_assigner;
157} ____cacheline_internodealigned_in_smp;
158
159// Update-side data structure used to check RCU readers.
160struct rcu_torture {
161 struct rcu_head rtort_rcu;
162 int rtort_pipe_count;
163 struct list_head rtort_free;
164 int rtort_mbtest;
165 struct rcu_torture_reader_check *rtort_chkp;
166};
167
168static LIST_HEAD(rcu_torture_freelist);
169static struct rcu_torture __rcu *rcu_torture_current;
170static unsigned long rcu_torture_current_version;
171static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
172static DEFINE_SPINLOCK(rcu_torture_lock);
173static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count);
174static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch);
175static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
176static struct rcu_torture_reader_check *rcu_torture_reader_mbchk;
177static atomic_t n_rcu_torture_alloc;
178static atomic_t n_rcu_torture_alloc_fail;
179static atomic_t n_rcu_torture_free;
180static atomic_t n_rcu_torture_mberror;
181static atomic_t n_rcu_torture_mbchk_fail;
182static atomic_t n_rcu_torture_mbchk_tries;
183static atomic_t n_rcu_torture_error;
184static long n_rcu_torture_barrier_error;
185static long n_rcu_torture_boost_ktrerror;
186static long n_rcu_torture_boost_rterror;
187static long n_rcu_torture_boost_failure;
188static long n_rcu_torture_boosts;
189static atomic_long_t n_rcu_torture_timers;
190static long n_barrier_attempts;
191static long n_barrier_successes; /* did rcu_barrier test succeed? */
192static unsigned long n_read_exits;
193static struct list_head rcu_torture_removed;
194static unsigned long shutdown_jiffies;
195static unsigned long start_gp_seq;
196static atomic_long_t n_nocb_offload;
197static atomic_long_t n_nocb_deoffload;
198
199static int rcu_torture_writer_state;
200#define RTWS_FIXED_DELAY 0
201#define RTWS_DELAY 1
202#define RTWS_REPLACE 2
203#define RTWS_DEF_FREE 3
204#define RTWS_EXP_SYNC 4
205#define RTWS_COND_GET 5
206#define RTWS_COND_SYNC 6
207#define RTWS_POLL_GET 7
208#define RTWS_POLL_WAIT 8
209#define RTWS_SYNC 9
210#define RTWS_STUTTER 10
211#define RTWS_STOPPING 11
212static const char * const rcu_torture_writer_state_names[] = {
213 "RTWS_FIXED_DELAY",
214 "RTWS_DELAY",
215 "RTWS_REPLACE",
216 "RTWS_DEF_FREE",
217 "RTWS_EXP_SYNC",
218 "RTWS_COND_GET",
219 "RTWS_COND_SYNC",
220 "RTWS_POLL_GET",
221 "RTWS_POLL_WAIT",
222 "RTWS_SYNC",
223 "RTWS_STUTTER",
224 "RTWS_STOPPING",
225};
226
227/* Record reader segment types and duration for first failing read. */
228struct rt_read_seg {
229 int rt_readstate;
230 unsigned long rt_delay_jiffies;
231 unsigned long rt_delay_ms;
232 unsigned long rt_delay_us;
233 bool rt_preempted;
234};
235static int err_segs_recorded;
236static struct rt_read_seg err_segs[RCUTORTURE_RDR_MAX_SEGS];
237static int rt_read_nsegs;
238
239static const char *rcu_torture_writer_state_getname(void)
240{
241 unsigned int i = READ_ONCE(rcu_torture_writer_state);
242
243 if (i >= ARRAY_SIZE(rcu_torture_writer_state_names))
244 return "???";
245 return rcu_torture_writer_state_names[i];
246}
247
248#ifdef CONFIG_RCU_TRACE
249static u64 notrace rcu_trace_clock_local(void)
250{
251 u64 ts = trace_clock_local();
252
253 (void)do_div(ts, NSEC_PER_USEC);
254 return ts;
255}
256#else /* #ifdef CONFIG_RCU_TRACE */
257static u64 notrace rcu_trace_clock_local(void)
258{
259 return 0ULL;
260}
261#endif /* #else #ifdef CONFIG_RCU_TRACE */
262
263/*
264 * Stop aggressive CPU-hog tests a bit before the end of the test in order
265 * to avoid interfering with test shutdown.
266 */
267static bool shutdown_time_arrived(void)
268{
269 return shutdown_secs && time_after(jiffies, shutdown_jiffies - 30 * HZ);
270}
271
272static unsigned long boost_starttime; /* jiffies of next boost test start. */
273static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
274 /* and boost task create/destroy. */
275static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
276static bool barrier_phase; /* Test phase. */
277static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
278static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
279static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
280
281static bool rcu_fwd_cb_nodelay; /* Short rcu_torture_delay() delays. */
282
283/*
284 * Allocate an element from the rcu_tortures pool.
285 */
286static struct rcu_torture *
287rcu_torture_alloc(void)
288{
289 struct list_head *p;
290
291 spin_lock_bh(&rcu_torture_lock);
292 if (list_empty(&rcu_torture_freelist)) {
293 atomic_inc(&n_rcu_torture_alloc_fail);
294 spin_unlock_bh(&rcu_torture_lock);
295 return NULL;
296 }
297 atomic_inc(&n_rcu_torture_alloc);
298 p = rcu_torture_freelist.next;
299 list_del_init(p);
300 spin_unlock_bh(&rcu_torture_lock);
301 return container_of(p, struct rcu_torture, rtort_free);
302}
303
304/*
305 * Free an element to the rcu_tortures pool.
306 */
307static void
308rcu_torture_free(struct rcu_torture *p)
309{
310 atomic_inc(&n_rcu_torture_free);
311 spin_lock_bh(&rcu_torture_lock);
312 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
313 spin_unlock_bh(&rcu_torture_lock);
314}
315
316/*
317 * Operations vector for selecting different types of tests.
318 */
319
320struct rcu_torture_ops {
321 int ttype;
322 void (*init)(void);
323 void (*cleanup)(void);
324 int (*readlock)(void);
325 void (*read_delay)(struct torture_random_state *rrsp,
326 struct rt_read_seg *rtrsp);
327 void (*readunlock)(int idx);
328 int (*readlock_held)(void);
329 unsigned long (*get_gp_seq)(void);
330 unsigned long (*gp_diff)(unsigned long new, unsigned long old);
331 void (*deferred_free)(struct rcu_torture *p);
332 void (*sync)(void);
333 void (*exp_sync)(void);
334 unsigned long (*get_gp_state)(void);
335 unsigned long (*start_gp_poll)(void);
336 bool (*poll_gp_state)(unsigned long oldstate);
337 void (*cond_sync)(unsigned long oldstate);
338 call_rcu_func_t call;
339 void (*cb_barrier)(void);
340 void (*fqs)(void);
341 void (*stats)(void);
342 void (*gp_kthread_dbg)(void);
343 bool (*check_boost_failed)(unsigned long gp_state, int *cpup);
344 int (*stall_dur)(void);
345 int irq_capable;
346 int can_boost;
347 int extendables;
348 int slow_gps;
349 const char *name;
350};
351
352static struct rcu_torture_ops *cur_ops;
353
354/*
355 * Definitions for rcu torture testing.
356 */
357
358static int torture_readlock_not_held(void)
359{
360 return rcu_read_lock_bh_held() || rcu_read_lock_sched_held();
361}
362
363static int rcu_torture_read_lock(void) __acquires(RCU)
364{
365 rcu_read_lock();
366 return 0;
367}
368
369static void
370rcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
371{
372 unsigned long started;
373 unsigned long completed;
374 const unsigned long shortdelay_us = 200;
375 unsigned long longdelay_ms = 300;
376 unsigned long long ts;
377
378 /* We want a short delay sometimes to make a reader delay the grace
379 * period, and we want a long delay occasionally to trigger
380 * force_quiescent_state. */
381
382 if (!READ_ONCE(rcu_fwd_cb_nodelay) &&
383 !(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) {
384 started = cur_ops->get_gp_seq();
385 ts = rcu_trace_clock_local();
386 if (preempt_count() & (SOFTIRQ_MASK | HARDIRQ_MASK))
387 longdelay_ms = 5; /* Avoid triggering BH limits. */
388 mdelay(longdelay_ms);
389 rtrsp->rt_delay_ms = longdelay_ms;
390 completed = cur_ops->get_gp_seq();
391 do_trace_rcu_torture_read(cur_ops->name, NULL, ts,
392 started, completed);
393 }
394 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) {
395 udelay(shortdelay_us);
396 rtrsp->rt_delay_us = shortdelay_us;
397 }
398 if (!preempt_count() &&
399 !(torture_random(rrsp) % (nrealreaders * 500))) {
400 torture_preempt_schedule(); /* QS only if preemptible. */
401 rtrsp->rt_preempted = true;
402 }
403}
404
405static void rcu_torture_read_unlock(int idx) __releases(RCU)
406{
407 rcu_read_unlock();
408}
409
410/*
411 * Update callback in the pipe. This should be invoked after a grace period.
412 */
413static bool
414rcu_torture_pipe_update_one(struct rcu_torture *rp)
415{
416 int i;
417 struct rcu_torture_reader_check *rtrcp = READ_ONCE(rp->rtort_chkp);
418
419 if (rtrcp) {
420 WRITE_ONCE(rp->rtort_chkp, NULL);
421 smp_store_release(&rtrcp->rtc_ready, 1); // Pair with smp_load_acquire().
422 }
423 i = READ_ONCE(rp->rtort_pipe_count);
424 if (i > RCU_TORTURE_PIPE_LEN)
425 i = RCU_TORTURE_PIPE_LEN;
426 atomic_inc(&rcu_torture_wcount[i]);
427 WRITE_ONCE(rp->rtort_pipe_count, i + 1);
428 if (rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
429 rp->rtort_mbtest = 0;
430 return true;
431 }
432 return false;
433}
434
435/*
436 * Update all callbacks in the pipe. Suitable for synchronous grace-period
437 * primitives.
438 */
439static void
440rcu_torture_pipe_update(struct rcu_torture *old_rp)
441{
442 struct rcu_torture *rp;
443 struct rcu_torture *rp1;
444
445 if (old_rp)
446 list_add(&old_rp->rtort_free, &rcu_torture_removed);
447 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
448 if (rcu_torture_pipe_update_one(rp)) {
449 list_del(&rp->rtort_free);
450 rcu_torture_free(rp);
451 }
452 }
453}
454
455static void
456rcu_torture_cb(struct rcu_head *p)
457{
458 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
459
460 if (torture_must_stop_irq()) {
461 /* Test is ending, just drop callbacks on the floor. */
462 /* The next initialization will pick up the pieces. */
463 return;
464 }
465 if (rcu_torture_pipe_update_one(rp))
466 rcu_torture_free(rp);
467 else
468 cur_ops->deferred_free(rp);
469}
470
471static unsigned long rcu_no_completed(void)
472{
473 return 0;
474}
475
476static void rcu_torture_deferred_free(struct rcu_torture *p)
477{
478 call_rcu(&p->rtort_rcu, rcu_torture_cb);
479}
480
481static void rcu_sync_torture_init(void)
482{
483 INIT_LIST_HEAD(&rcu_torture_removed);
484}
485
486static struct rcu_torture_ops rcu_ops = {
487 .ttype = RCU_FLAVOR,
488 .init = rcu_sync_torture_init,
489 .readlock = rcu_torture_read_lock,
490 .read_delay = rcu_read_delay,
491 .readunlock = rcu_torture_read_unlock,
492 .readlock_held = torture_readlock_not_held,
493 .get_gp_seq = rcu_get_gp_seq,
494 .gp_diff = rcu_seq_diff,
495 .deferred_free = rcu_torture_deferred_free,
496 .sync = synchronize_rcu,
497 .exp_sync = synchronize_rcu_expedited,
498 .get_gp_state = get_state_synchronize_rcu,
499 .start_gp_poll = start_poll_synchronize_rcu,
500 .poll_gp_state = poll_state_synchronize_rcu,
501 .cond_sync = cond_synchronize_rcu,
502 .call = call_rcu,
503 .cb_barrier = rcu_barrier,
504 .fqs = rcu_force_quiescent_state,
505 .stats = NULL,
506 .gp_kthread_dbg = show_rcu_gp_kthreads,
507 .check_boost_failed = rcu_check_boost_fail,
508 .stall_dur = rcu_jiffies_till_stall_check,
509 .irq_capable = 1,
510 .can_boost = IS_ENABLED(CONFIG_RCU_BOOST),
511 .extendables = RCUTORTURE_MAX_EXTEND,
512 .name = "rcu"
513};
514
515/*
516 * Don't even think about trying any of these in real life!!!
517 * The names includes "busted", and they really means it!
518 * The only purpose of these functions is to provide a buggy RCU
519 * implementation to make sure that rcutorture correctly emits
520 * buggy-RCU error messages.
521 */
522static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
523{
524 /* This is a deliberate bug for testing purposes only! */
525 rcu_torture_cb(&p->rtort_rcu);
526}
527
528static void synchronize_rcu_busted(void)
529{
530 /* This is a deliberate bug for testing purposes only! */
531}
532
533static void
534call_rcu_busted(struct rcu_head *head, rcu_callback_t func)
535{
536 /* This is a deliberate bug for testing purposes only! */
537 func(head);
538}
539
540static struct rcu_torture_ops rcu_busted_ops = {
541 .ttype = INVALID_RCU_FLAVOR,
542 .init = rcu_sync_torture_init,
543 .readlock = rcu_torture_read_lock,
544 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
545 .readunlock = rcu_torture_read_unlock,
546 .readlock_held = torture_readlock_not_held,
547 .get_gp_seq = rcu_no_completed,
548 .deferred_free = rcu_busted_torture_deferred_free,
549 .sync = synchronize_rcu_busted,
550 .exp_sync = synchronize_rcu_busted,
551 .call = call_rcu_busted,
552 .cb_barrier = NULL,
553 .fqs = NULL,
554 .stats = NULL,
555 .irq_capable = 1,
556 .name = "busted"
557};
558
559/*
560 * Definitions for srcu torture testing.
561 */
562
563DEFINE_STATIC_SRCU(srcu_ctl);
564static struct srcu_struct srcu_ctld;
565static struct srcu_struct *srcu_ctlp = &srcu_ctl;
566
567static int srcu_torture_read_lock(void) __acquires(srcu_ctlp)
568{
569 return srcu_read_lock(srcu_ctlp);
570}
571
572static void
573srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
574{
575 long delay;
576 const long uspertick = 1000000 / HZ;
577 const long longdelay = 10;
578
579 /* We want there to be long-running readers, but not all the time. */
580
581 delay = torture_random(rrsp) %
582 (nrealreaders * 2 * longdelay * uspertick);
583 if (!delay && in_task()) {
584 schedule_timeout_interruptible(longdelay);
585 rtrsp->rt_delay_jiffies = longdelay;
586 } else {
587 rcu_read_delay(rrsp, rtrsp);
588 }
589}
590
591static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp)
592{
593 srcu_read_unlock(srcu_ctlp, idx);
594}
595
596static int torture_srcu_read_lock_held(void)
597{
598 return srcu_read_lock_held(srcu_ctlp);
599}
600
601static unsigned long srcu_torture_completed(void)
602{
603 return srcu_batches_completed(srcu_ctlp);
604}
605
606static void srcu_torture_deferred_free(struct rcu_torture *rp)
607{
608 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
609}
610
611static void srcu_torture_synchronize(void)
612{
613 synchronize_srcu(srcu_ctlp);
614}
615
616static unsigned long srcu_torture_get_gp_state(void)
617{
618 return get_state_synchronize_srcu(srcu_ctlp);
619}
620
621static unsigned long srcu_torture_start_gp_poll(void)
622{
623 return start_poll_synchronize_srcu(srcu_ctlp);
624}
625
626static bool srcu_torture_poll_gp_state(unsigned long oldstate)
627{
628 return poll_state_synchronize_srcu(srcu_ctlp, oldstate);
629}
630
631static void srcu_torture_call(struct rcu_head *head,
632 rcu_callback_t func)
633{
634 call_srcu(srcu_ctlp, head, func);
635}
636
637static void srcu_torture_barrier(void)
638{
639 srcu_barrier(srcu_ctlp);
640}
641
642static void srcu_torture_stats(void)
643{
644 srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG);
645}
646
647static void srcu_torture_synchronize_expedited(void)
648{
649 synchronize_srcu_expedited(srcu_ctlp);
650}
651
652static struct rcu_torture_ops srcu_ops = {
653 .ttype = SRCU_FLAVOR,
654 .init = rcu_sync_torture_init,
655 .readlock = srcu_torture_read_lock,
656 .read_delay = srcu_read_delay,
657 .readunlock = srcu_torture_read_unlock,
658 .readlock_held = torture_srcu_read_lock_held,
659 .get_gp_seq = srcu_torture_completed,
660 .deferred_free = srcu_torture_deferred_free,
661 .sync = srcu_torture_synchronize,
662 .exp_sync = srcu_torture_synchronize_expedited,
663 .get_gp_state = srcu_torture_get_gp_state,
664 .start_gp_poll = srcu_torture_start_gp_poll,
665 .poll_gp_state = srcu_torture_poll_gp_state,
666 .call = srcu_torture_call,
667 .cb_barrier = srcu_torture_barrier,
668 .stats = srcu_torture_stats,
669 .irq_capable = 1,
670 .name = "srcu"
671};
672
673static void srcu_torture_init(void)
674{
675 rcu_sync_torture_init();
676 WARN_ON(init_srcu_struct(&srcu_ctld));
677 srcu_ctlp = &srcu_ctld;
678}
679
680static void srcu_torture_cleanup(void)
681{
682 cleanup_srcu_struct(&srcu_ctld);
683 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
684}
685
686/* As above, but dynamically allocated. */
687static struct rcu_torture_ops srcud_ops = {
688 .ttype = SRCU_FLAVOR,
689 .init = srcu_torture_init,
690 .cleanup = srcu_torture_cleanup,
691 .readlock = srcu_torture_read_lock,
692 .read_delay = srcu_read_delay,
693 .readunlock = srcu_torture_read_unlock,
694 .readlock_held = torture_srcu_read_lock_held,
695 .get_gp_seq = srcu_torture_completed,
696 .deferred_free = srcu_torture_deferred_free,
697 .sync = srcu_torture_synchronize,
698 .exp_sync = srcu_torture_synchronize_expedited,
699 .call = srcu_torture_call,
700 .cb_barrier = srcu_torture_barrier,
701 .stats = srcu_torture_stats,
702 .irq_capable = 1,
703 .name = "srcud"
704};
705
706/* As above, but broken due to inappropriate reader extension. */
707static struct rcu_torture_ops busted_srcud_ops = {
708 .ttype = SRCU_FLAVOR,
709 .init = srcu_torture_init,
710 .cleanup = srcu_torture_cleanup,
711 .readlock = srcu_torture_read_lock,
712 .read_delay = rcu_read_delay,
713 .readunlock = srcu_torture_read_unlock,
714 .readlock_held = torture_srcu_read_lock_held,
715 .get_gp_seq = srcu_torture_completed,
716 .deferred_free = srcu_torture_deferred_free,
717 .sync = srcu_torture_synchronize,
718 .exp_sync = srcu_torture_synchronize_expedited,
719 .call = srcu_torture_call,
720 .cb_barrier = srcu_torture_barrier,
721 .stats = srcu_torture_stats,
722 .irq_capable = 1,
723 .extendables = RCUTORTURE_MAX_EXTEND,
724 .name = "busted_srcud"
725};
726
727/*
728 * Definitions for RCU-tasks torture testing.
729 */
730
731static int tasks_torture_read_lock(void)
732{
733 return 0;
734}
735
736static void tasks_torture_read_unlock(int idx)
737{
738}
739
740static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
741{
742 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
743}
744
745static void synchronize_rcu_mult_test(void)
746{
747 synchronize_rcu_mult(call_rcu_tasks, call_rcu);
748}
749
750static struct rcu_torture_ops tasks_ops = {
751 .ttype = RCU_TASKS_FLAVOR,
752 .init = rcu_sync_torture_init,
753 .readlock = tasks_torture_read_lock,
754 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
755 .readunlock = tasks_torture_read_unlock,
756 .get_gp_seq = rcu_no_completed,
757 .deferred_free = rcu_tasks_torture_deferred_free,
758 .sync = synchronize_rcu_tasks,
759 .exp_sync = synchronize_rcu_mult_test,
760 .call = call_rcu_tasks,
761 .cb_barrier = rcu_barrier_tasks,
762 .gp_kthread_dbg = show_rcu_tasks_classic_gp_kthread,
763 .fqs = NULL,
764 .stats = NULL,
765 .irq_capable = 1,
766 .slow_gps = 1,
767 .name = "tasks"
768};
769
770/*
771 * Definitions for trivial CONFIG_PREEMPT=n-only torture testing.
772 * This implementation does not necessarily work well with CPU hotplug.
773 */
774
775static void synchronize_rcu_trivial(void)
776{
777 int cpu;
778
779 for_each_online_cpu(cpu) {
780 rcutorture_sched_setaffinity(current->pid, cpumask_of(cpu));
781 WARN_ON_ONCE(raw_smp_processor_id() != cpu);
782 }
783}
784
785static int rcu_torture_read_lock_trivial(void) __acquires(RCU)
786{
787 preempt_disable();
788 return 0;
789}
790
791static void rcu_torture_read_unlock_trivial(int idx) __releases(RCU)
792{
793 preempt_enable();
794}
795
796static struct rcu_torture_ops trivial_ops = {
797 .ttype = RCU_TRIVIAL_FLAVOR,
798 .init = rcu_sync_torture_init,
799 .readlock = rcu_torture_read_lock_trivial,
800 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
801 .readunlock = rcu_torture_read_unlock_trivial,
802 .readlock_held = torture_readlock_not_held,
803 .get_gp_seq = rcu_no_completed,
804 .sync = synchronize_rcu_trivial,
805 .exp_sync = synchronize_rcu_trivial,
806 .fqs = NULL,
807 .stats = NULL,
808 .irq_capable = 1,
809 .name = "trivial"
810};
811
812/*
813 * Definitions for rude RCU-tasks torture testing.
814 */
815
816static void rcu_tasks_rude_torture_deferred_free(struct rcu_torture *p)
817{
818 call_rcu_tasks_rude(&p->rtort_rcu, rcu_torture_cb);
819}
820
821static struct rcu_torture_ops tasks_rude_ops = {
822 .ttype = RCU_TASKS_RUDE_FLAVOR,
823 .init = rcu_sync_torture_init,
824 .readlock = rcu_torture_read_lock_trivial,
825 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
826 .readunlock = rcu_torture_read_unlock_trivial,
827 .get_gp_seq = rcu_no_completed,
828 .deferred_free = rcu_tasks_rude_torture_deferred_free,
829 .sync = synchronize_rcu_tasks_rude,
830 .exp_sync = synchronize_rcu_tasks_rude,
831 .call = call_rcu_tasks_rude,
832 .cb_barrier = rcu_barrier_tasks_rude,
833 .gp_kthread_dbg = show_rcu_tasks_rude_gp_kthread,
834 .fqs = NULL,
835 .stats = NULL,
836 .irq_capable = 1,
837 .name = "tasks-rude"
838};
839
840/*
841 * Definitions for tracing RCU-tasks torture testing.
842 */
843
844static int tasks_tracing_torture_read_lock(void)
845{
846 rcu_read_lock_trace();
847 return 0;
848}
849
850static void tasks_tracing_torture_read_unlock(int idx)
851{
852 rcu_read_unlock_trace();
853}
854
855static void rcu_tasks_tracing_torture_deferred_free(struct rcu_torture *p)
856{
857 call_rcu_tasks_trace(&p->rtort_rcu, rcu_torture_cb);
858}
859
860static struct rcu_torture_ops tasks_tracing_ops = {
861 .ttype = RCU_TASKS_TRACING_FLAVOR,
862 .init = rcu_sync_torture_init,
863 .readlock = tasks_tracing_torture_read_lock,
864 .read_delay = srcu_read_delay, /* just reuse srcu's version. */
865 .readunlock = tasks_tracing_torture_read_unlock,
866 .readlock_held = rcu_read_lock_trace_held,
867 .get_gp_seq = rcu_no_completed,
868 .deferred_free = rcu_tasks_tracing_torture_deferred_free,
869 .sync = synchronize_rcu_tasks_trace,
870 .exp_sync = synchronize_rcu_tasks_trace,
871 .call = call_rcu_tasks_trace,
872 .cb_barrier = rcu_barrier_tasks_trace,
873 .gp_kthread_dbg = show_rcu_tasks_trace_gp_kthread,
874 .fqs = NULL,
875 .stats = NULL,
876 .irq_capable = 1,
877 .slow_gps = 1,
878 .name = "tasks-tracing"
879};
880
881static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old)
882{
883 if (!cur_ops->gp_diff)
884 return new - old;
885 return cur_ops->gp_diff(new, old);
886}
887
888/*
889 * RCU torture priority-boost testing. Runs one real-time thread per
890 * CPU for moderate bursts, repeatedly starting grace periods and waiting
891 * for them to complete. If a given grace period takes too long, we assume
892 * that priority inversion has occurred.
893 */
894
895static int old_rt_runtime = -1;
896
897static void rcu_torture_disable_rt_throttle(void)
898{
899 /*
900 * Disable RT throttling so that rcutorture's boost threads don't get
901 * throttled. Only possible if rcutorture is built-in otherwise the
902 * user should manually do this by setting the sched_rt_period_us and
903 * sched_rt_runtime sysctls.
904 */
905 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime != -1)
906 return;
907
908 old_rt_runtime = sysctl_sched_rt_runtime;
909 sysctl_sched_rt_runtime = -1;
910}
911
912static void rcu_torture_enable_rt_throttle(void)
913{
914 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime == -1)
915 return;
916
917 sysctl_sched_rt_runtime = old_rt_runtime;
918 old_rt_runtime = -1;
919}
920
921static bool rcu_torture_boost_failed(unsigned long gp_state, unsigned long *start)
922{
923 int cpu;
924 static int dbg_done;
925 unsigned long end = jiffies;
926 bool gp_done;
927 unsigned long j;
928 static unsigned long last_persist;
929 unsigned long lp;
930 unsigned long mininterval = test_boost_duration * HZ - HZ / 2;
931
932 if (end - *start > mininterval) {
933 // Recheck after checking time to avoid false positives.
934 smp_mb(); // Time check before grace-period check.
935 if (cur_ops->poll_gp_state(gp_state))
936 return false; // passed, though perhaps just barely
937 if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, &cpu)) {
938 // At most one persisted message per boost test.
939 j = jiffies;
940 lp = READ_ONCE(last_persist);
941 if (time_after(j, lp + mininterval) && cmpxchg(&last_persist, lp, j) == lp)
942 pr_info("Boost inversion persisted: No QS from CPU %d\n", cpu);
943 return false; // passed on a technicality
944 }
945 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
946 n_rcu_torture_boost_failure++;
947 if (!xchg(&dbg_done, 1) && cur_ops->gp_kthread_dbg) {
948 pr_info("Boost inversion thread ->rt_priority %u gp_state %lu jiffies %lu\n",
949 current->rt_priority, gp_state, end - *start);
950 cur_ops->gp_kthread_dbg();
951 // Recheck after print to flag grace period ending during splat.
952 gp_done = cur_ops->poll_gp_state(gp_state);
953 pr_info("Boost inversion: GP %lu %s.\n", gp_state,
954 gp_done ? "ended already" : "still pending");
955
956 }
957
958 return true; // failed
959 } else if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, NULL)) {
960 *start = jiffies;
961 }
962
963 return false; // passed
964}
965
966static int rcu_torture_boost(void *arg)
967{
968 unsigned long endtime;
969 unsigned long gp_state;
970 unsigned long gp_state_time;
971 unsigned long oldstarttime;
972
973 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
974
975 /* Set real-time priority. */
976 sched_set_fifo_low(current);
977
978 /* Each pass through the following loop does one boost-test cycle. */
979 do {
980 bool failed = false; // Test failed already in this test interval
981 bool gp_initiated = false;
982
983 if (kthread_should_stop())
984 goto checkwait;
985
986 /* Wait for the next test interval. */
987 oldstarttime = boost_starttime;
988 while (time_before(jiffies, oldstarttime)) {
989 schedule_timeout_interruptible(oldstarttime - jiffies);
990 if (stutter_wait("rcu_torture_boost"))
991 sched_set_fifo_low(current);
992 if (torture_must_stop())
993 goto checkwait;
994 }
995
996 // Do one boost-test interval.
997 endtime = oldstarttime + test_boost_duration * HZ;
998 while (time_before(jiffies, endtime)) {
999 // Has current GP gone too long?
1000 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state))
1001 failed = rcu_torture_boost_failed(gp_state, &gp_state_time);
1002 // If we don't have a grace period in flight, start one.
1003 if (!gp_initiated || cur_ops->poll_gp_state(gp_state)) {
1004 gp_state = cur_ops->start_gp_poll();
1005 gp_initiated = true;
1006 gp_state_time = jiffies;
1007 }
1008 if (stutter_wait("rcu_torture_boost")) {
1009 sched_set_fifo_low(current);
1010 // If the grace period already ended,
1011 // we don't know when that happened, so
1012 // start over.
1013 if (cur_ops->poll_gp_state(gp_state))
1014 gp_initiated = false;
1015 }
1016 if (torture_must_stop())
1017 goto checkwait;
1018 }
1019
1020 // In case the grace period extended beyond the end of the loop.
1021 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state))
1022 rcu_torture_boost_failed(gp_state, &gp_state_time);
1023
1024 /*
1025 * Set the start time of the next test interval.
1026 * Yes, this is vulnerable to long delays, but such
1027 * delays simply cause a false negative for the next
1028 * interval. Besides, we are running at RT priority,
1029 * so delays should be relatively rare.
1030 */
1031 while (oldstarttime == boost_starttime && !kthread_should_stop()) {
1032 if (mutex_trylock(&boost_mutex)) {
1033 if (oldstarttime == boost_starttime) {
1034 boost_starttime = jiffies + test_boost_interval * HZ;
1035 n_rcu_torture_boosts++;
1036 }
1037 mutex_unlock(&boost_mutex);
1038 break;
1039 }
1040 schedule_timeout_uninterruptible(1);
1041 }
1042
1043 /* Go do the stutter. */
1044checkwait: if (stutter_wait("rcu_torture_boost"))
1045 sched_set_fifo_low(current);
1046 } while (!torture_must_stop());
1047
1048 /* Clean up and exit. */
1049 while (!kthread_should_stop()) {
1050 torture_shutdown_absorb("rcu_torture_boost");
1051 schedule_timeout_uninterruptible(1);
1052 }
1053 torture_kthread_stopping("rcu_torture_boost");
1054 return 0;
1055}
1056
1057/*
1058 * RCU torture force-quiescent-state kthread. Repeatedly induces
1059 * bursts of calls to force_quiescent_state(), increasing the probability
1060 * of occurrence of some important types of race conditions.
1061 */
1062static int
1063rcu_torture_fqs(void *arg)
1064{
1065 unsigned long fqs_resume_time;
1066 int fqs_burst_remaining;
1067 int oldnice = task_nice(current);
1068
1069 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
1070 do {
1071 fqs_resume_time = jiffies + fqs_stutter * HZ;
1072 while (time_before(jiffies, fqs_resume_time) &&
1073 !kthread_should_stop()) {
1074 schedule_timeout_interruptible(1);
1075 }
1076 fqs_burst_remaining = fqs_duration;
1077 while (fqs_burst_remaining > 0 &&
1078 !kthread_should_stop()) {
1079 cur_ops->fqs();
1080 udelay(fqs_holdoff);
1081 fqs_burst_remaining -= fqs_holdoff;
1082 }
1083 if (stutter_wait("rcu_torture_fqs"))
1084 sched_set_normal(current, oldnice);
1085 } while (!torture_must_stop());
1086 torture_kthread_stopping("rcu_torture_fqs");
1087 return 0;
1088}
1089
1090// Used by writers to randomly choose from the available grace-period
1091// primitives. The only purpose of the initialization is to size the array.
1092static int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC, RTWS_COND_GET, RTWS_POLL_GET, RTWS_SYNC };
1093static int nsynctypes;
1094
1095/*
1096 * Determine which grace-period primitives are available.
1097 */
1098static void rcu_torture_write_types(void)
1099{
1100 bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal;
1101 bool gp_poll1 = gp_poll, gp_sync1 = gp_sync;
1102
1103 /* Initialize synctype[] array. If none set, take default. */
1104 if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_poll1 && !gp_sync1)
1105 gp_cond1 = gp_exp1 = gp_normal1 = gp_poll1 = gp_sync1 = true;
1106 if (gp_cond1 && cur_ops->get_gp_state && cur_ops->cond_sync) {
1107 synctype[nsynctypes++] = RTWS_COND_GET;
1108 pr_info("%s: Testing conditional GPs.\n", __func__);
1109 } else if (gp_cond && (!cur_ops->get_gp_state || !cur_ops->cond_sync)) {
1110 pr_alert("%s: gp_cond without primitives.\n", __func__);
1111 }
1112 if (gp_exp1 && cur_ops->exp_sync) {
1113 synctype[nsynctypes++] = RTWS_EXP_SYNC;
1114 pr_info("%s: Testing expedited GPs.\n", __func__);
1115 } else if (gp_exp && !cur_ops->exp_sync) {
1116 pr_alert("%s: gp_exp without primitives.\n", __func__);
1117 }
1118 if (gp_normal1 && cur_ops->deferred_free) {
1119 synctype[nsynctypes++] = RTWS_DEF_FREE;
1120 pr_info("%s: Testing asynchronous GPs.\n", __func__);
1121 } else if (gp_normal && !cur_ops->deferred_free) {
1122 pr_alert("%s: gp_normal without primitives.\n", __func__);
1123 }
1124 if (gp_poll1 && cur_ops->start_gp_poll && cur_ops->poll_gp_state) {
1125 synctype[nsynctypes++] = RTWS_POLL_GET;
1126 pr_info("%s: Testing polling GPs.\n", __func__);
1127 } else if (gp_poll && (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)) {
1128 pr_alert("%s: gp_poll without primitives.\n", __func__);
1129 }
1130 if (gp_sync1 && cur_ops->sync) {
1131 synctype[nsynctypes++] = RTWS_SYNC;
1132 pr_info("%s: Testing normal GPs.\n", __func__);
1133 } else if (gp_sync && !cur_ops->sync) {
1134 pr_alert("%s: gp_sync without primitives.\n", __func__);
1135 }
1136}
1137
1138/*
1139 * RCU torture writer kthread. Repeatedly substitutes a new structure
1140 * for that pointed to by rcu_torture_current, freeing the old structure
1141 * after a series of grace periods (the "pipeline").
1142 */
1143static int
1144rcu_torture_writer(void *arg)
1145{
1146 bool boot_ended;
1147 bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
1148 unsigned long cookie;
1149 int expediting = 0;
1150 unsigned long gp_snap;
1151 int i;
1152 int idx;
1153 int oldnice = task_nice(current);
1154 struct rcu_torture *rp;
1155 struct rcu_torture *old_rp;
1156 static DEFINE_TORTURE_RANDOM(rand);
1157 bool stutter_waited;
1158
1159 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
1160 if (!can_expedite)
1161 pr_alert("%s" TORTURE_FLAG
1162 " GP expediting controlled from boot/sysfs for %s.\n",
1163 torture_type, cur_ops->name);
1164 if (WARN_ONCE(nsynctypes == 0,
1165 "rcu_torture_writer: No update-side primitives.\n")) {
1166 /*
1167 * No updates primitives, so don't try updating.
1168 * The resulting test won't be testing much, hence the
1169 * above WARN_ONCE().
1170 */
1171 rcu_torture_writer_state = RTWS_STOPPING;
1172 torture_kthread_stopping("rcu_torture_writer");
1173 }
1174
1175 do {
1176 rcu_torture_writer_state = RTWS_FIXED_DELAY;
1177 torture_hrtimeout_us(500, 1000, &rand);
1178 rp = rcu_torture_alloc();
1179 if (rp == NULL)
1180 continue;
1181 rp->rtort_pipe_count = 0;
1182 rcu_torture_writer_state = RTWS_DELAY;
1183 udelay(torture_random(&rand) & 0x3ff);
1184 rcu_torture_writer_state = RTWS_REPLACE;
1185 old_rp = rcu_dereference_check(rcu_torture_current,
1186 current == writer_task);
1187 rp->rtort_mbtest = 1;
1188 rcu_assign_pointer(rcu_torture_current, rp);
1189 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
1190 if (old_rp) {
1191 i = old_rp->rtort_pipe_count;
1192 if (i > RCU_TORTURE_PIPE_LEN)
1193 i = RCU_TORTURE_PIPE_LEN;
1194 atomic_inc(&rcu_torture_wcount[i]);
1195 WRITE_ONCE(old_rp->rtort_pipe_count,
1196 old_rp->rtort_pipe_count + 1);
1197 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) {
1198 idx = cur_ops->readlock();
1199 cookie = cur_ops->get_gp_state();
1200 WARN_ONCE(rcu_torture_writer_state != RTWS_DEF_FREE &&
1201 cur_ops->poll_gp_state(cookie),
1202 "%s: Cookie check 1 failed %s(%d) %lu->%lu\n",
1203 __func__,
1204 rcu_torture_writer_state_getname(),
1205 rcu_torture_writer_state,
1206 cookie, cur_ops->get_gp_state());
1207 cur_ops->readunlock(idx);
1208 }
1209 switch (synctype[torture_random(&rand) % nsynctypes]) {
1210 case RTWS_DEF_FREE:
1211 rcu_torture_writer_state = RTWS_DEF_FREE;
1212 cur_ops->deferred_free(old_rp);
1213 break;
1214 case RTWS_EXP_SYNC:
1215 rcu_torture_writer_state = RTWS_EXP_SYNC;
1216 cur_ops->exp_sync();
1217 rcu_torture_pipe_update(old_rp);
1218 break;
1219 case RTWS_COND_GET:
1220 rcu_torture_writer_state = RTWS_COND_GET;
1221 gp_snap = cur_ops->get_gp_state();
1222 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1223 rcu_torture_writer_state = RTWS_COND_SYNC;
1224 cur_ops->cond_sync(gp_snap);
1225 rcu_torture_pipe_update(old_rp);
1226 break;
1227 case RTWS_POLL_GET:
1228 rcu_torture_writer_state = RTWS_POLL_GET;
1229 gp_snap = cur_ops->start_gp_poll();
1230 rcu_torture_writer_state = RTWS_POLL_WAIT;
1231 while (!cur_ops->poll_gp_state(gp_snap))
1232 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1233 &rand);
1234 rcu_torture_pipe_update(old_rp);
1235 break;
1236 case RTWS_SYNC:
1237 rcu_torture_writer_state = RTWS_SYNC;
1238 cur_ops->sync();
1239 rcu_torture_pipe_update(old_rp);
1240 break;
1241 default:
1242 WARN_ON_ONCE(1);
1243 break;
1244 }
1245 }
1246 WRITE_ONCE(rcu_torture_current_version,
1247 rcu_torture_current_version + 1);
1248 /* Cycle through nesting levels of rcu_expedite_gp() calls. */
1249 if (can_expedite &&
1250 !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
1251 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
1252 if (expediting >= 0)
1253 rcu_expedite_gp();
1254 else
1255 rcu_unexpedite_gp();
1256 if (++expediting > 3)
1257 expediting = -expediting;
1258 } else if (!can_expedite) { /* Disabled during boot, recheck. */
1259 can_expedite = !rcu_gp_is_expedited() &&
1260 !rcu_gp_is_normal();
1261 }
1262 rcu_torture_writer_state = RTWS_STUTTER;
1263 boot_ended = rcu_inkernel_boot_has_ended();
1264 stutter_waited = stutter_wait("rcu_torture_writer");
1265 if (stutter_waited &&
1266 !READ_ONCE(rcu_fwd_cb_nodelay) &&
1267 !cur_ops->slow_gps &&
1268 !torture_must_stop() &&
1269 boot_ended)
1270 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++)
1271 if (list_empty(&rcu_tortures[i].rtort_free) &&
1272 rcu_access_pointer(rcu_torture_current) !=
1273 &rcu_tortures[i]) {
1274 rcu_ftrace_dump(DUMP_ALL);
1275 WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count);
1276 }
1277 if (stutter_waited)
1278 sched_set_normal(current, oldnice);
1279 } while (!torture_must_stop());
1280 rcu_torture_current = NULL; // Let stats task know that we are done.
1281 /* Reset expediting back to unexpedited. */
1282 if (expediting > 0)
1283 expediting = -expediting;
1284 while (can_expedite && expediting++ < 0)
1285 rcu_unexpedite_gp();
1286 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
1287 if (!can_expedite)
1288 pr_alert("%s" TORTURE_FLAG
1289 " Dynamic grace-period expediting was disabled.\n",
1290 torture_type);
1291 rcu_torture_writer_state = RTWS_STOPPING;
1292 torture_kthread_stopping("rcu_torture_writer");
1293 return 0;
1294}
1295
1296/*
1297 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
1298 * delay between calls.
1299 */
1300static int
1301rcu_torture_fakewriter(void *arg)
1302{
1303 unsigned long gp_snap;
1304 DEFINE_TORTURE_RANDOM(rand);
1305
1306 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1307 set_user_nice(current, MAX_NICE);
1308
1309 do {
1310 torture_hrtimeout_jiffies(torture_random(&rand) % 10, &rand);
1311 if (cur_ops->cb_barrier != NULL &&
1312 torture_random(&rand) % (nfakewriters * 8) == 0) {
1313 cur_ops->cb_barrier();
1314 } else {
1315 switch (synctype[torture_random(&rand) % nsynctypes]) {
1316 case RTWS_DEF_FREE:
1317 break;
1318 case RTWS_EXP_SYNC:
1319 cur_ops->exp_sync();
1320 break;
1321 case RTWS_COND_GET:
1322 gp_snap = cur_ops->get_gp_state();
1323 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1324 cur_ops->cond_sync(gp_snap);
1325 break;
1326 case RTWS_POLL_GET:
1327 gp_snap = cur_ops->start_gp_poll();
1328 while (!cur_ops->poll_gp_state(gp_snap)) {
1329 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1330 &rand);
1331 }
1332 break;
1333 case RTWS_SYNC:
1334 cur_ops->sync();
1335 break;
1336 default:
1337 WARN_ON_ONCE(1);
1338 break;
1339 }
1340 }
1341 stutter_wait("rcu_torture_fakewriter");
1342 } while (!torture_must_stop());
1343
1344 torture_kthread_stopping("rcu_torture_fakewriter");
1345 return 0;
1346}
1347
1348static void rcu_torture_timer_cb(struct rcu_head *rhp)
1349{
1350 kfree(rhp);
1351}
1352
1353// Set up and carry out testing of RCU's global memory ordering
1354static void rcu_torture_reader_do_mbchk(long myid, struct rcu_torture *rtp,
1355 struct torture_random_state *trsp)
1356{
1357 unsigned long loops;
1358 int noc = torture_num_online_cpus();
1359 int rdrchked;
1360 int rdrchker;
1361 struct rcu_torture_reader_check *rtrcp; // Me.
1362 struct rcu_torture_reader_check *rtrcp_assigner; // Assigned us to do checking.
1363 struct rcu_torture_reader_check *rtrcp_chked; // Reader being checked.
1364 struct rcu_torture_reader_check *rtrcp_chker; // Reader doing checking when not me.
1365
1366 if (myid < 0)
1367 return; // Don't try this from timer handlers.
1368
1369 // Increment my counter.
1370 rtrcp = &rcu_torture_reader_mbchk[myid];
1371 WRITE_ONCE(rtrcp->rtc_myloops, rtrcp->rtc_myloops + 1);
1372
1373 // Attempt to assign someone else some checking work.
1374 rdrchked = torture_random(trsp) % nrealreaders;
1375 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked];
1376 rdrchker = torture_random(trsp) % nrealreaders;
1377 rtrcp_chker = &rcu_torture_reader_mbchk[rdrchker];
1378 if (rdrchked != myid && rdrchked != rdrchker && noc >= rdrchked && noc >= rdrchker &&
1379 smp_load_acquire(&rtrcp->rtc_chkrdr) < 0 && // Pairs with smp_store_release below.
1380 !READ_ONCE(rtp->rtort_chkp) &&
1381 !smp_load_acquire(&rtrcp_chker->rtc_assigner)) { // Pairs with smp_store_release below.
1382 rtrcp->rtc_chkloops = READ_ONCE(rtrcp_chked->rtc_myloops);
1383 WARN_ON_ONCE(rtrcp->rtc_chkrdr >= 0);
1384 rtrcp->rtc_chkrdr = rdrchked;
1385 WARN_ON_ONCE(rtrcp->rtc_ready); // This gets set after the grace period ends.
1386 if (cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, NULL, rtrcp) ||
1387 cmpxchg_relaxed(&rtp->rtort_chkp, NULL, rtrcp))
1388 (void)cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, rtrcp, NULL); // Back out.
1389 }
1390
1391 // If assigned some completed work, do it!
1392 rtrcp_assigner = READ_ONCE(rtrcp->rtc_assigner);
1393 if (!rtrcp_assigner || !smp_load_acquire(&rtrcp_assigner->rtc_ready))
1394 return; // No work or work not yet ready.
1395 rdrchked = rtrcp_assigner->rtc_chkrdr;
1396 if (WARN_ON_ONCE(rdrchked < 0))
1397 return;
1398 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked];
1399 loops = READ_ONCE(rtrcp_chked->rtc_myloops);
1400 atomic_inc(&n_rcu_torture_mbchk_tries);
1401 if (ULONG_CMP_LT(loops, rtrcp_assigner->rtc_chkloops))
1402 atomic_inc(&n_rcu_torture_mbchk_fail);
1403 rtrcp_assigner->rtc_chkloops = loops + ULONG_MAX / 2;
1404 rtrcp_assigner->rtc_ready = 0;
1405 smp_store_release(&rtrcp->rtc_assigner, NULL); // Someone else can assign us work.
1406 smp_store_release(&rtrcp_assigner->rtc_chkrdr, -1); // Assigner can again assign.
1407}
1408
1409/*
1410 * Do one extension of an RCU read-side critical section using the
1411 * current reader state in readstate (set to zero for initial entry
1412 * to extended critical section), set the new state as specified by
1413 * newstate (set to zero for final exit from extended critical section),
1414 * and random-number-generator state in trsp. If this is neither the
1415 * beginning or end of the critical section and if there was actually a
1416 * change, do a ->read_delay().
1417 */
1418static void rcutorture_one_extend(int *readstate, int newstate,
1419 struct torture_random_state *trsp,
1420 struct rt_read_seg *rtrsp)
1421{
1422 unsigned long flags;
1423 int idxnew = -1;
1424 int idxold = *readstate;
1425 int statesnew = ~*readstate & newstate;
1426 int statesold = *readstate & ~newstate;
1427
1428 WARN_ON_ONCE(idxold < 0);
1429 WARN_ON_ONCE((idxold >> RCUTORTURE_RDR_SHIFT) > 1);
1430 rtrsp->rt_readstate = newstate;
1431
1432 /* First, put new protection in place to avoid critical-section gap. */
1433 if (statesnew & RCUTORTURE_RDR_BH)
1434 local_bh_disable();
1435 if (statesnew & RCUTORTURE_RDR_IRQ)
1436 local_irq_disable();
1437 if (statesnew & RCUTORTURE_RDR_PREEMPT)
1438 preempt_disable();
1439 if (statesnew & RCUTORTURE_RDR_RBH)
1440 rcu_read_lock_bh();
1441 if (statesnew & RCUTORTURE_RDR_SCHED)
1442 rcu_read_lock_sched();
1443 if (statesnew & RCUTORTURE_RDR_RCU)
1444 idxnew = cur_ops->readlock() << RCUTORTURE_RDR_SHIFT;
1445
1446 /* Next, remove old protection, irq first due to bh conflict. */
1447 if (statesold & RCUTORTURE_RDR_IRQ)
1448 local_irq_enable();
1449 if (statesold & RCUTORTURE_RDR_BH)
1450 local_bh_enable();
1451 if (statesold & RCUTORTURE_RDR_PREEMPT)
1452 preempt_enable();
1453 if (statesold & RCUTORTURE_RDR_RBH)
1454 rcu_read_unlock_bh();
1455 if (statesold & RCUTORTURE_RDR_SCHED)
1456 rcu_read_unlock_sched();
1457 if (statesold & RCUTORTURE_RDR_RCU) {
1458 bool lockit = !statesnew && !(torture_random(trsp) & 0xffff);
1459
1460 if (lockit)
1461 raw_spin_lock_irqsave(¤t->pi_lock, flags);
1462 cur_ops->readunlock(idxold >> RCUTORTURE_RDR_SHIFT);
1463 if (lockit)
1464 raw_spin_unlock_irqrestore(¤t->pi_lock, flags);
1465 }
1466
1467 /* Delay if neither beginning nor end and there was a change. */
1468 if ((statesnew || statesold) && *readstate && newstate)
1469 cur_ops->read_delay(trsp, rtrsp);
1470
1471 /* Update the reader state. */
1472 if (idxnew == -1)
1473 idxnew = idxold & ~RCUTORTURE_RDR_MASK;
1474 WARN_ON_ONCE(idxnew < 0);
1475 WARN_ON_ONCE((idxnew >> RCUTORTURE_RDR_SHIFT) > 1);
1476 *readstate = idxnew | newstate;
1477 WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT) < 0);
1478 WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT) > 1);
1479}
1480
1481/* Return the biggest extendables mask given current RCU and boot parameters. */
1482static int rcutorture_extend_mask_max(void)
1483{
1484 int mask;
1485
1486 WARN_ON_ONCE(extendables & ~RCUTORTURE_MAX_EXTEND);
1487 mask = extendables & RCUTORTURE_MAX_EXTEND & cur_ops->extendables;
1488 mask = mask | RCUTORTURE_RDR_RCU;
1489 return mask;
1490}
1491
1492/* Return a random protection state mask, but with at least one bit set. */
1493static int
1494rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp)
1495{
1496 int mask = rcutorture_extend_mask_max();
1497 unsigned long randmask1 = torture_random(trsp) >> 8;
1498 unsigned long randmask2 = randmask1 >> 3;
1499
1500 WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT);
1501 /* Mostly only one bit (need preemption!), sometimes lots of bits. */
1502 if (!(randmask1 & 0x7))
1503 mask = mask & randmask2;
1504 else
1505 mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS));
1506 /* Can't enable bh w/irq disabled. */
1507 if ((mask & RCUTORTURE_RDR_IRQ) &&
1508 ((!(mask & RCUTORTURE_RDR_BH) && (oldmask & RCUTORTURE_RDR_BH)) ||
1509 (!(mask & RCUTORTURE_RDR_RBH) && (oldmask & RCUTORTURE_RDR_RBH))))
1510 mask |= RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH;
1511 return mask ?: RCUTORTURE_RDR_RCU;
1512}
1513
1514/*
1515 * Do a randomly selected number of extensions of an existing RCU read-side
1516 * critical section.
1517 */
1518static struct rt_read_seg *
1519rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp,
1520 struct rt_read_seg *rtrsp)
1521{
1522 int i;
1523 int j;
1524 int mask = rcutorture_extend_mask_max();
1525
1526 WARN_ON_ONCE(!*readstate); /* -Existing- RCU read-side critsect! */
1527 if (!((mask - 1) & mask))
1528 return rtrsp; /* Current RCU reader not extendable. */
1529 /* Bias towards larger numbers of loops. */
1530 i = (torture_random(trsp) >> 3);
1531 i = ((i | (i >> 3)) & RCUTORTURE_RDR_MAX_LOOPS) + 1;
1532 for (j = 0; j < i; j++) {
1533 mask = rcutorture_extend_mask(*readstate, trsp);
1534 rcutorture_one_extend(readstate, mask, trsp, &rtrsp[j]);
1535 }
1536 return &rtrsp[j];
1537}
1538
1539/*
1540 * Do one read-side critical section, returning false if there was
1541 * no data to read. Can be invoked both from process context and
1542 * from a timer handler.
1543 */
1544static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid)
1545{
1546 unsigned long cookie;
1547 int i;
1548 unsigned long started;
1549 unsigned long completed;
1550 int newstate;
1551 struct rcu_torture *p;
1552 int pipe_count;
1553 int readstate = 0;
1554 struct rt_read_seg rtseg[RCUTORTURE_RDR_MAX_SEGS] = { { 0 } };
1555 struct rt_read_seg *rtrsp = &rtseg[0];
1556 struct rt_read_seg *rtrsp1;
1557 unsigned long long ts;
1558
1559 WARN_ON_ONCE(!rcu_is_watching());
1560 newstate = rcutorture_extend_mask(readstate, trsp);
1561 rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++);
1562 if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
1563 cookie = cur_ops->get_gp_state();
1564 started = cur_ops->get_gp_seq();
1565 ts = rcu_trace_clock_local();
1566 p = rcu_dereference_check(rcu_torture_current,
1567 !cur_ops->readlock_held || cur_ops->readlock_held());
1568 if (p == NULL) {
1569 /* Wait for rcu_torture_writer to get underway */
1570 rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
1571 return false;
1572 }
1573 if (p->rtort_mbtest == 0)
1574 atomic_inc(&n_rcu_torture_mberror);
1575 rcu_torture_reader_do_mbchk(myid, p, trsp);
1576 rtrsp = rcutorture_loop_extend(&readstate, trsp, rtrsp);
1577 preempt_disable();
1578 pipe_count = READ_ONCE(p->rtort_pipe_count);
1579 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1580 /* Should not happen, but... */
1581 pipe_count = RCU_TORTURE_PIPE_LEN;
1582 }
1583 completed = cur_ops->get_gp_seq();
1584 if (pipe_count > 1) {
1585 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
1586 ts, started, completed);
1587 rcu_ftrace_dump(DUMP_ALL);
1588 }
1589 __this_cpu_inc(rcu_torture_count[pipe_count]);
1590 completed = rcutorture_seq_diff(completed, started);
1591 if (completed > RCU_TORTURE_PIPE_LEN) {
1592 /* Should not happen, but... */
1593 completed = RCU_TORTURE_PIPE_LEN;
1594 }
1595 __this_cpu_inc(rcu_torture_batch[completed]);
1596 preempt_enable();
1597 if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
1598 WARN_ONCE(cur_ops->poll_gp_state(cookie),
1599 "%s: Cookie check 2 failed %s(%d) %lu->%lu\n",
1600 __func__,
1601 rcu_torture_writer_state_getname(),
1602 rcu_torture_writer_state,
1603 cookie, cur_ops->get_gp_state());
1604 rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
1605 WARN_ON_ONCE(readstate & RCUTORTURE_RDR_MASK);
1606 // This next splat is expected behavior if leakpointer, especially
1607 // for CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels.
1608 WARN_ON_ONCE(leakpointer && READ_ONCE(p->rtort_pipe_count) > 1);
1609
1610 /* If error or close call, record the sequence of reader protections. */
1611 if ((pipe_count > 1 || completed > 1) && !xchg(&err_segs_recorded, 1)) {
1612 i = 0;
1613 for (rtrsp1 = &rtseg[0]; rtrsp1 < rtrsp; rtrsp1++)
1614 err_segs[i++] = *rtrsp1;
1615 rt_read_nsegs = i;
1616 }
1617
1618 return true;
1619}
1620
1621static DEFINE_TORTURE_RANDOM_PERCPU(rcu_torture_timer_rand);
1622
1623/*
1624 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
1625 * incrementing the corresponding element of the pipeline array. The
1626 * counter in the element should never be greater than 1, otherwise, the
1627 * RCU implementation is broken.
1628 */
1629static void rcu_torture_timer(struct timer_list *unused)
1630{
1631 atomic_long_inc(&n_rcu_torture_timers);
1632 (void)rcu_torture_one_read(this_cpu_ptr(&rcu_torture_timer_rand), -1);
1633
1634 /* Test call_rcu() invocation from interrupt handler. */
1635 if (cur_ops->call) {
1636 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT);
1637
1638 if (rhp)
1639 cur_ops->call(rhp, rcu_torture_timer_cb);
1640 }
1641}
1642
1643/*
1644 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
1645 * incrementing the corresponding element of the pipeline array. The
1646 * counter in the element should never be greater than 1, otherwise, the
1647 * RCU implementation is broken.
1648 */
1649static int
1650rcu_torture_reader(void *arg)
1651{
1652 unsigned long lastsleep = jiffies;
1653 long myid = (long)arg;
1654 int mynumonline = myid;
1655 DEFINE_TORTURE_RANDOM(rand);
1656 struct timer_list t;
1657
1658 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
1659 set_user_nice(current, MAX_NICE);
1660 if (irqreader && cur_ops->irq_capable)
1661 timer_setup_on_stack(&t, rcu_torture_timer, 0);
1662 tick_dep_set_task(current, TICK_DEP_BIT_RCU);
1663 do {
1664 if (irqreader && cur_ops->irq_capable) {
1665 if (!timer_pending(&t))
1666 mod_timer(&t, jiffies + 1);
1667 }
1668 if (!rcu_torture_one_read(&rand, myid) && !torture_must_stop())
1669 schedule_timeout_interruptible(HZ);
1670 if (time_after(jiffies, lastsleep) && !torture_must_stop()) {
1671 torture_hrtimeout_us(500, 1000, &rand);
1672 lastsleep = jiffies + 10;
1673 }
1674 while (torture_num_online_cpus() < mynumonline && !torture_must_stop())
1675 schedule_timeout_interruptible(HZ / 5);
1676 stutter_wait("rcu_torture_reader");
1677 } while (!torture_must_stop());
1678 if (irqreader && cur_ops->irq_capable) {
1679 del_timer_sync(&t);
1680 destroy_timer_on_stack(&t);
1681 }
1682 tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
1683 torture_kthread_stopping("rcu_torture_reader");
1684 return 0;
1685}
1686
1687/*
1688 * Randomly Toggle CPUs' callback-offload state. This uses hrtimers to
1689 * increase race probabilities and fuzzes the interval between toggling.
1690 */
1691static int rcu_nocb_toggle(void *arg)
1692{
1693 int cpu;
1694 int maxcpu = -1;
1695 int oldnice = task_nice(current);
1696 long r;
1697 DEFINE_TORTURE_RANDOM(rand);
1698 ktime_t toggle_delay;
1699 unsigned long toggle_fuzz;
1700 ktime_t toggle_interval = ms_to_ktime(nocbs_toggle);
1701
1702 VERBOSE_TOROUT_STRING("rcu_nocb_toggle task started");
1703 while (!rcu_inkernel_boot_has_ended())
1704 schedule_timeout_interruptible(HZ / 10);
1705 for_each_online_cpu(cpu)
1706 maxcpu = cpu;
1707 WARN_ON(maxcpu < 0);
1708 if (toggle_interval > ULONG_MAX)
1709 toggle_fuzz = ULONG_MAX >> 3;
1710 else
1711 toggle_fuzz = toggle_interval >> 3;
1712 if (toggle_fuzz <= 0)
1713 toggle_fuzz = NSEC_PER_USEC;
1714 do {
1715 r = torture_random(&rand);
1716 cpu = (r >> 4) % (maxcpu + 1);
1717 if (r & 0x1) {
1718 rcu_nocb_cpu_offload(cpu);
1719 atomic_long_inc(&n_nocb_offload);
1720 } else {
1721 rcu_nocb_cpu_deoffload(cpu);
1722 atomic_long_inc(&n_nocb_deoffload);
1723 }
1724 toggle_delay = torture_random(&rand) % toggle_fuzz + toggle_interval;
1725 set_current_state(TASK_INTERRUPTIBLE);
1726 schedule_hrtimeout(&toggle_delay, HRTIMER_MODE_REL);
1727 if (stutter_wait("rcu_nocb_toggle"))
1728 sched_set_normal(current, oldnice);
1729 } while (!torture_must_stop());
1730 torture_kthread_stopping("rcu_nocb_toggle");
1731 return 0;
1732}
1733
1734/*
1735 * Print torture statistics. Caller must ensure that there is only
1736 * one call to this function at a given time!!! This is normally
1737 * accomplished by relying on the module system to only have one copy
1738 * of the module loaded, and then by giving the rcu_torture_stats
1739 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1740 * thread is not running).
1741 */
1742static void
1743rcu_torture_stats_print(void)
1744{
1745 int cpu;
1746 int i;
1747 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1748 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1749 struct rcu_torture *rtcp;
1750 static unsigned long rtcv_snap = ULONG_MAX;
1751 static bool splatted;
1752 struct task_struct *wtp;
1753
1754 for_each_possible_cpu(cpu) {
1755 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1756 pipesummary[i] += READ_ONCE(per_cpu(rcu_torture_count, cpu)[i]);
1757 batchsummary[i] += READ_ONCE(per_cpu(rcu_torture_batch, cpu)[i]);
1758 }
1759 }
1760 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
1761 if (pipesummary[i] != 0)
1762 break;
1763 }
1764
1765 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1766 rtcp = rcu_access_pointer(rcu_torture_current);
1767 pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
1768 rtcp,
1769 rtcp && !rcu_stall_is_suppressed_at_boot() ? "ver" : "VER",
1770 rcu_torture_current_version,
1771 list_empty(&rcu_torture_freelist),
1772 atomic_read(&n_rcu_torture_alloc),
1773 atomic_read(&n_rcu_torture_alloc_fail),
1774 atomic_read(&n_rcu_torture_free));
1775 pr_cont("rtmbe: %d rtmbkf: %d/%d rtbe: %ld rtbke: %ld rtbre: %ld ",
1776 atomic_read(&n_rcu_torture_mberror),
1777 atomic_read(&n_rcu_torture_mbchk_fail), atomic_read(&n_rcu_torture_mbchk_tries),
1778 n_rcu_torture_barrier_error,
1779 n_rcu_torture_boost_ktrerror,
1780 n_rcu_torture_boost_rterror);
1781 pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
1782 n_rcu_torture_boost_failure,
1783 n_rcu_torture_boosts,
1784 atomic_long_read(&n_rcu_torture_timers));
1785 torture_onoff_stats();
1786 pr_cont("barrier: %ld/%ld:%ld ",
1787 data_race(n_barrier_successes),
1788 data_race(n_barrier_attempts),
1789 data_race(n_rcu_torture_barrier_error));
1790 pr_cont("read-exits: %ld ", data_race(n_read_exits)); // Statistic.
1791 pr_cont("nocb-toggles: %ld:%ld\n",
1792 atomic_long_read(&n_nocb_offload), atomic_long_read(&n_nocb_deoffload));
1793
1794 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1795 if (atomic_read(&n_rcu_torture_mberror) ||
1796 atomic_read(&n_rcu_torture_mbchk_fail) ||
1797 n_rcu_torture_barrier_error || n_rcu_torture_boost_ktrerror ||
1798 n_rcu_torture_boost_rterror || n_rcu_torture_boost_failure ||
1799 i > 1) {
1800 pr_cont("%s", "!!! ");
1801 atomic_inc(&n_rcu_torture_error);
1802 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mberror));
1803 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mbchk_fail));
1804 WARN_ON_ONCE(n_rcu_torture_barrier_error); // rcu_barrier()
1805 WARN_ON_ONCE(n_rcu_torture_boost_ktrerror); // no boost kthread
1806 WARN_ON_ONCE(n_rcu_torture_boost_rterror); // can't set RT prio
1807 WARN_ON_ONCE(n_rcu_torture_boost_failure); // boost failed (TIMER_SOFTIRQ RT prio?)
1808 WARN_ON_ONCE(i > 1); // Too-short grace period
1809 }
1810 pr_cont("Reader Pipe: ");
1811 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1812 pr_cont(" %ld", pipesummary[i]);
1813 pr_cont("\n");
1814
1815 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1816 pr_cont("Reader Batch: ");
1817 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1818 pr_cont(" %ld", batchsummary[i]);
1819 pr_cont("\n");
1820
1821 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1822 pr_cont("Free-Block Circulation: ");
1823 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1824 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
1825 }
1826 pr_cont("\n");
1827
1828 if (cur_ops->stats)
1829 cur_ops->stats();
1830 if (rtcv_snap == rcu_torture_current_version &&
1831 rcu_access_pointer(rcu_torture_current) &&
1832 !rcu_stall_is_suppressed()) {
1833 int __maybe_unused flags = 0;
1834 unsigned long __maybe_unused gp_seq = 0;
1835
1836 rcutorture_get_gp_data(cur_ops->ttype,
1837 &flags, &gp_seq);
1838 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp,
1839 &flags, &gp_seq);
1840 wtp = READ_ONCE(writer_task);
1841 pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#x cpu %d\n",
1842 rcu_torture_writer_state_getname(),
1843 rcu_torture_writer_state, gp_seq, flags,
1844 wtp == NULL ? ~0U : wtp->__state,
1845 wtp == NULL ? -1 : (int)task_cpu(wtp));
1846 if (!splatted && wtp) {
1847 sched_show_task(wtp);
1848 splatted = true;
1849 }
1850 if (cur_ops->gp_kthread_dbg)
1851 cur_ops->gp_kthread_dbg();
1852 rcu_ftrace_dump(DUMP_ALL);
1853 }
1854 rtcv_snap = rcu_torture_current_version;
1855}
1856
1857/*
1858 * Periodically prints torture statistics, if periodic statistics printing
1859 * was specified via the stat_interval module parameter.
1860 */
1861static int
1862rcu_torture_stats(void *arg)
1863{
1864 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1865 do {
1866 schedule_timeout_interruptible(stat_interval * HZ);
1867 rcu_torture_stats_print();
1868 torture_shutdown_absorb("rcu_torture_stats");
1869 } while (!torture_must_stop());
1870 torture_kthread_stopping("rcu_torture_stats");
1871 return 0;
1872}
1873
1874/* Test mem_dump_obj() and friends. */
1875static void rcu_torture_mem_dump_obj(void)
1876{
1877 struct rcu_head *rhp;
1878 struct kmem_cache *kcp;
1879 static int z;
1880
1881 kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL);
1882 rhp = kmem_cache_alloc(kcp, GFP_KERNEL);
1883 pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z);
1884 pr_alert("mem_dump_obj(ZERO_SIZE_PTR):");
1885 mem_dump_obj(ZERO_SIZE_PTR);
1886 pr_alert("mem_dump_obj(NULL):");
1887 mem_dump_obj(NULL);
1888 pr_alert("mem_dump_obj(%px):", &rhp);
1889 mem_dump_obj(&rhp);
1890 pr_alert("mem_dump_obj(%px):", rhp);
1891 mem_dump_obj(rhp);
1892 pr_alert("mem_dump_obj(%px):", &rhp->func);
1893 mem_dump_obj(&rhp->func);
1894 pr_alert("mem_dump_obj(%px):", &z);
1895 mem_dump_obj(&z);
1896 kmem_cache_free(kcp, rhp);
1897 kmem_cache_destroy(kcp);
1898 rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
1899 pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
1900 pr_alert("mem_dump_obj(kmalloc %px):", rhp);
1901 mem_dump_obj(rhp);
1902 pr_alert("mem_dump_obj(kmalloc %px):", &rhp->func);
1903 mem_dump_obj(&rhp->func);
1904 kfree(rhp);
1905 rhp = vmalloc(4096);
1906 pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
1907 pr_alert("mem_dump_obj(vmalloc %px):", rhp);
1908 mem_dump_obj(rhp);
1909 pr_alert("mem_dump_obj(vmalloc %px):", &rhp->func);
1910 mem_dump_obj(&rhp->func);
1911 vfree(rhp);
1912}
1913
1914static void
1915rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1916{
1917 pr_alert("%s" TORTURE_FLAG
1918 "--- %s: nreaders=%d nfakewriters=%d "
1919 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1920 "shuffle_interval=%d stutter=%d irqreader=%d "
1921 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1922 "test_boost=%d/%d test_boost_interval=%d "
1923 "test_boost_duration=%d shutdown_secs=%d "
1924 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d "
1925 "stall_cpu_block=%d "
1926 "n_barrier_cbs=%d "
1927 "onoff_interval=%d onoff_holdoff=%d "
1928 "read_exit_delay=%d read_exit_burst=%d "
1929 "nocbs_nthreads=%d nocbs_toggle=%d\n",
1930 torture_type, tag, nrealreaders, nfakewriters,
1931 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1932 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1933 test_boost, cur_ops->can_boost,
1934 test_boost_interval, test_boost_duration, shutdown_secs,
1935 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff,
1936 stall_cpu_block,
1937 n_barrier_cbs,
1938 onoff_interval, onoff_holdoff,
1939 read_exit_delay, read_exit_burst,
1940 nocbs_nthreads, nocbs_toggle);
1941}
1942
1943static int rcutorture_booster_cleanup(unsigned int cpu)
1944{
1945 struct task_struct *t;
1946
1947 if (boost_tasks[cpu] == NULL)
1948 return 0;
1949 mutex_lock(&boost_mutex);
1950 t = boost_tasks[cpu];
1951 boost_tasks[cpu] = NULL;
1952 rcu_torture_enable_rt_throttle();
1953 mutex_unlock(&boost_mutex);
1954
1955 /* This must be outside of the mutex, otherwise deadlock! */
1956 torture_stop_kthread(rcu_torture_boost, t);
1957 return 0;
1958}
1959
1960static int rcutorture_booster_init(unsigned int cpu)
1961{
1962 int retval;
1963
1964 if (boost_tasks[cpu] != NULL)
1965 return 0; /* Already created, nothing more to do. */
1966
1967 /* Don't allow time recalculation while creating a new task. */
1968 mutex_lock(&boost_mutex);
1969 rcu_torture_disable_rt_throttle();
1970 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
1971 boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
1972 cpu_to_node(cpu),
1973 "rcu_torture_boost");
1974 if (IS_ERR(boost_tasks[cpu])) {
1975 retval = PTR_ERR(boost_tasks[cpu]);
1976 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
1977 n_rcu_torture_boost_ktrerror++;
1978 boost_tasks[cpu] = NULL;
1979 mutex_unlock(&boost_mutex);
1980 return retval;
1981 }
1982 kthread_bind(boost_tasks[cpu], cpu);
1983 wake_up_process(boost_tasks[cpu]);
1984 mutex_unlock(&boost_mutex);
1985 return 0;
1986}
1987
1988/*
1989 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
1990 * induces a CPU stall for the time specified by stall_cpu.
1991 */
1992static int rcu_torture_stall(void *args)
1993{
1994 int idx;
1995 unsigned long stop_at;
1996
1997 VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
1998 if (stall_cpu_holdoff > 0) {
1999 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
2000 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
2001 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
2002 }
2003 if (!kthread_should_stop() && stall_gp_kthread > 0) {
2004 VERBOSE_TOROUT_STRING("rcu_torture_stall begin GP stall");
2005 rcu_gp_set_torture_wait(stall_gp_kthread * HZ);
2006 for (idx = 0; idx < stall_gp_kthread + 2; idx++) {
2007 if (kthread_should_stop())
2008 break;
2009 schedule_timeout_uninterruptible(HZ);
2010 }
2011 }
2012 if (!kthread_should_stop() && stall_cpu > 0) {
2013 VERBOSE_TOROUT_STRING("rcu_torture_stall begin CPU stall");
2014 stop_at = ktime_get_seconds() + stall_cpu;
2015 /* RCU CPU stall is expected behavior in following code. */
2016 idx = cur_ops->readlock();
2017 if (stall_cpu_irqsoff)
2018 local_irq_disable();
2019 else if (!stall_cpu_block)
2020 preempt_disable();
2021 pr_alert("%s start on CPU %d.\n",
2022 __func__, raw_smp_processor_id());
2023 while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(),
2024 stop_at))
2025 if (stall_cpu_block)
2026 schedule_timeout_uninterruptible(HZ);
2027 if (stall_cpu_irqsoff)
2028 local_irq_enable();
2029 else if (!stall_cpu_block)
2030 preempt_enable();
2031 cur_ops->readunlock(idx);
2032 }
2033 pr_alert("%s end.\n", __func__);
2034 torture_shutdown_absorb("rcu_torture_stall");
2035 while (!kthread_should_stop())
2036 schedule_timeout_interruptible(10 * HZ);
2037 return 0;
2038}
2039
2040/* Spawn CPU-stall kthread, if stall_cpu specified. */
2041static int __init rcu_torture_stall_init(void)
2042{
2043 if (stall_cpu <= 0 && stall_gp_kthread <= 0)
2044 return 0;
2045 return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
2046}
2047
2048/* State structure for forward-progress self-propagating RCU callback. */
2049struct fwd_cb_state {
2050 struct rcu_head rh;
2051 int stop;
2052};
2053
2054/*
2055 * Forward-progress self-propagating RCU callback function. Because
2056 * callbacks run from softirq, this function is an implicit RCU read-side
2057 * critical section.
2058 */
2059static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp)
2060{
2061 struct fwd_cb_state *fcsp = container_of(rhp, struct fwd_cb_state, rh);
2062
2063 if (READ_ONCE(fcsp->stop)) {
2064 WRITE_ONCE(fcsp->stop, 2);
2065 return;
2066 }
2067 cur_ops->call(&fcsp->rh, rcu_torture_fwd_prog_cb);
2068}
2069
2070/* State for continuous-flood RCU callbacks. */
2071struct rcu_fwd_cb {
2072 struct rcu_head rh;
2073 struct rcu_fwd_cb *rfc_next;
2074 struct rcu_fwd *rfc_rfp;
2075 int rfc_gps;
2076};
2077
2078#define MAX_FWD_CB_JIFFIES (8 * HZ) /* Maximum CB test duration. */
2079#define MIN_FWD_CB_LAUNDERS 3 /* This many CB invocations to count. */
2080#define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */
2081#define FWD_CBS_HIST_DIV 10 /* Histogram buckets/second. */
2082#define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV))
2083
2084struct rcu_launder_hist {
2085 long n_launders;
2086 unsigned long launder_gp_seq;
2087};
2088
2089struct rcu_fwd {
2090 spinlock_t rcu_fwd_lock;
2091 struct rcu_fwd_cb *rcu_fwd_cb_head;
2092 struct rcu_fwd_cb **rcu_fwd_cb_tail;
2093 long n_launders_cb;
2094 unsigned long rcu_fwd_startat;
2095 struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST];
2096 unsigned long rcu_launder_gp_seq_start;
2097};
2098
2099static DEFINE_MUTEX(rcu_fwd_mutex);
2100static struct rcu_fwd *rcu_fwds;
2101static bool rcu_fwd_emergency_stop;
2102
2103static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp)
2104{
2105 unsigned long gps;
2106 unsigned long gps_old;
2107 int i;
2108 int j;
2109
2110 for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--)
2111 if (rfp->n_launders_hist[i].n_launders > 0)
2112 break;
2113 pr_alert("%s: Callback-invocation histogram (duration %lu jiffies):",
2114 __func__, jiffies - rfp->rcu_fwd_startat);
2115 gps_old = rfp->rcu_launder_gp_seq_start;
2116 for (j = 0; j <= i; j++) {
2117 gps = rfp->n_launders_hist[j].launder_gp_seq;
2118 pr_cont(" %ds/%d: %ld:%ld",
2119 j + 1, FWD_CBS_HIST_DIV,
2120 rfp->n_launders_hist[j].n_launders,
2121 rcutorture_seq_diff(gps, gps_old));
2122 gps_old = gps;
2123 }
2124 pr_cont("\n");
2125}
2126
2127/* Callback function for continuous-flood RCU callbacks. */
2128static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp)
2129{
2130 unsigned long flags;
2131 int i;
2132 struct rcu_fwd_cb *rfcp = container_of(rhp, struct rcu_fwd_cb, rh);
2133 struct rcu_fwd_cb **rfcpp;
2134 struct rcu_fwd *rfp = rfcp->rfc_rfp;
2135
2136 rfcp->rfc_next = NULL;
2137 rfcp->rfc_gps++;
2138 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
2139 rfcpp = rfp->rcu_fwd_cb_tail;
2140 rfp->rcu_fwd_cb_tail = &rfcp->rfc_next;
2141 WRITE_ONCE(*rfcpp, rfcp);
2142 WRITE_ONCE(rfp->n_launders_cb, rfp->n_launders_cb + 1);
2143 i = ((jiffies - rfp->rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV));
2144 if (i >= ARRAY_SIZE(rfp->n_launders_hist))
2145 i = ARRAY_SIZE(rfp->n_launders_hist) - 1;
2146 rfp->n_launders_hist[i].n_launders++;
2147 rfp->n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq();
2148 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
2149}
2150
2151// Give the scheduler a chance, even on nohz_full CPUs.
2152static void rcu_torture_fwd_prog_cond_resched(unsigned long iter)
2153{
2154 if (IS_ENABLED(CONFIG_PREEMPTION) && IS_ENABLED(CONFIG_NO_HZ_FULL)) {
2155 // Real call_rcu() floods hit userspace, so emulate that.
2156 if (need_resched() || (iter & 0xfff))
2157 schedule();
2158 return;
2159 }
2160 // No userspace emulation: CB invocation throttles call_rcu()
2161 cond_resched();
2162}
2163
2164/*
2165 * Free all callbacks on the rcu_fwd_cb_head list, either because the
2166 * test is over or because we hit an OOM event.
2167 */
2168static unsigned long rcu_torture_fwd_prog_cbfree(struct rcu_fwd *rfp)
2169{
2170 unsigned long flags;
2171 unsigned long freed = 0;
2172 struct rcu_fwd_cb *rfcp;
2173
2174 for (;;) {
2175 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
2176 rfcp = rfp->rcu_fwd_cb_head;
2177 if (!rfcp) {
2178 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
2179 break;
2180 }
2181 rfp->rcu_fwd_cb_head = rfcp->rfc_next;
2182 if (!rfp->rcu_fwd_cb_head)
2183 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head;
2184 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
2185 kfree(rfcp);
2186 freed++;
2187 rcu_torture_fwd_prog_cond_resched(freed);
2188 if (tick_nohz_full_enabled()) {
2189 local_irq_save(flags);
2190 rcu_momentary_dyntick_idle();
2191 local_irq_restore(flags);
2192 }
2193 }
2194 return freed;
2195}
2196
2197/* Carry out need_resched()/cond_resched() forward-progress testing. */
2198static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp,
2199 int *tested, int *tested_tries)
2200{
2201 unsigned long cver;
2202 unsigned long dur;
2203 struct fwd_cb_state fcs;
2204 unsigned long gps;
2205 int idx;
2206 int sd;
2207 int sd4;
2208 bool selfpropcb = false;
2209 unsigned long stopat;
2210 static DEFINE_TORTURE_RANDOM(trs);
2211
2212 if (!cur_ops->sync)
2213 return; // Cannot do need_resched() forward progress testing without ->sync.
2214 if (cur_ops->call && cur_ops->cb_barrier) {
2215 init_rcu_head_on_stack(&fcs.rh);
2216 selfpropcb = true;
2217 }
2218
2219 /* Tight loop containing cond_resched(). */
2220 WRITE_ONCE(rcu_fwd_cb_nodelay, true);
2221 cur_ops->sync(); /* Later readers see above write. */
2222 if (selfpropcb) {
2223 WRITE_ONCE(fcs.stop, 0);
2224 cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb);
2225 }
2226 cver = READ_ONCE(rcu_torture_current_version);
2227 gps = cur_ops->get_gp_seq();
2228 sd = cur_ops->stall_dur() + 1;
2229 sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div;
2230 dur = sd4 + torture_random(&trs) % (sd - sd4);
2231 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
2232 stopat = rfp->rcu_fwd_startat + dur;
2233 while (time_before(jiffies, stopat) &&
2234 !shutdown_time_arrived() &&
2235 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
2236 idx = cur_ops->readlock();
2237 udelay(10);
2238 cur_ops->readunlock(idx);
2239 if (!fwd_progress_need_resched || need_resched())
2240 cond_resched();
2241 }
2242 (*tested_tries)++;
2243 if (!time_before(jiffies, stopat) &&
2244 !shutdown_time_arrived() &&
2245 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
2246 (*tested)++;
2247 cver = READ_ONCE(rcu_torture_current_version) - cver;
2248 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
2249 WARN_ON(!cver && gps < 2);
2250 pr_alert("%s: Duration %ld cver %ld gps %ld\n", __func__, dur, cver, gps);
2251 }
2252 if (selfpropcb) {
2253 WRITE_ONCE(fcs.stop, 1);
2254 cur_ops->sync(); /* Wait for running CB to complete. */
2255 cur_ops->cb_barrier(); /* Wait for queued callbacks. */
2256 }
2257
2258 if (selfpropcb) {
2259 WARN_ON(READ_ONCE(fcs.stop) != 2);
2260 destroy_rcu_head_on_stack(&fcs.rh);
2261 }
2262 schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */
2263 WRITE_ONCE(rcu_fwd_cb_nodelay, false);
2264}
2265
2266/* Carry out call_rcu() forward-progress testing. */
2267static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp)
2268{
2269 unsigned long cver;
2270 unsigned long flags;
2271 unsigned long gps;
2272 int i;
2273 long n_launders;
2274 long n_launders_cb_snap;
2275 long n_launders_sa;
2276 long n_max_cbs;
2277 long n_max_gps;
2278 struct rcu_fwd_cb *rfcp;
2279 struct rcu_fwd_cb *rfcpn;
2280 unsigned long stopat;
2281 unsigned long stoppedat;
2282
2283 if (READ_ONCE(rcu_fwd_emergency_stop))
2284 return; /* Get out of the way quickly, no GP wait! */
2285 if (!cur_ops->call)
2286 return; /* Can't do call_rcu() fwd prog without ->call. */
2287
2288 /* Loop continuously posting RCU callbacks. */
2289 WRITE_ONCE(rcu_fwd_cb_nodelay, true);
2290 cur_ops->sync(); /* Later readers see above write. */
2291 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
2292 stopat = rfp->rcu_fwd_startat + MAX_FWD_CB_JIFFIES;
2293 n_launders = 0;
2294 rfp->n_launders_cb = 0; // Hoist initialization for multi-kthread
2295 n_launders_sa = 0;
2296 n_max_cbs = 0;
2297 n_max_gps = 0;
2298 for (i = 0; i < ARRAY_SIZE(rfp->n_launders_hist); i++)
2299 rfp->n_launders_hist[i].n_launders = 0;
2300 cver = READ_ONCE(rcu_torture_current_version);
2301 gps = cur_ops->get_gp_seq();
2302 rfp->rcu_launder_gp_seq_start = gps;
2303 tick_dep_set_task(current, TICK_DEP_BIT_RCU);
2304 while (time_before(jiffies, stopat) &&
2305 !shutdown_time_arrived() &&
2306 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
2307 rfcp = READ_ONCE(rfp->rcu_fwd_cb_head);
2308 rfcpn = NULL;
2309 if (rfcp)
2310 rfcpn = READ_ONCE(rfcp->rfc_next);
2311 if (rfcpn) {
2312 if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS &&
2313 ++n_max_gps >= MIN_FWD_CBS_LAUNDERED)
2314 break;
2315 rfp->rcu_fwd_cb_head = rfcpn;
2316 n_launders++;
2317 n_launders_sa++;
2318 } else {
2319 rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL);
2320 if (WARN_ON_ONCE(!rfcp)) {
2321 schedule_timeout_interruptible(1);
2322 continue;
2323 }
2324 n_max_cbs++;
2325 n_launders_sa = 0;
2326 rfcp->rfc_gps = 0;
2327 rfcp->rfc_rfp = rfp;
2328 }
2329 cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr);
2330 rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs);
2331 if (tick_nohz_full_enabled()) {
2332 local_irq_save(flags);
2333 rcu_momentary_dyntick_idle();
2334 local_irq_restore(flags);
2335 }
2336 }
2337 stoppedat = jiffies;
2338 n_launders_cb_snap = READ_ONCE(rfp->n_launders_cb);
2339 cver = READ_ONCE(rcu_torture_current_version) - cver;
2340 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
2341 cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */
2342 (void)rcu_torture_fwd_prog_cbfree(rfp);
2343
2344 if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) &&
2345 !shutdown_time_arrived()) {
2346 WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED);
2347 pr_alert("%s Duration %lu barrier: %lu pending %ld n_launders: %ld n_launders_sa: %ld n_max_gps: %ld n_max_cbs: %ld cver %ld gps %ld\n",
2348 __func__,
2349 stoppedat - rfp->rcu_fwd_startat, jiffies - stoppedat,
2350 n_launders + n_max_cbs - n_launders_cb_snap,
2351 n_launders, n_launders_sa,
2352 n_max_gps, n_max_cbs, cver, gps);
2353 rcu_torture_fwd_cb_hist(rfp);
2354 }
2355 schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */
2356 tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
2357 WRITE_ONCE(rcu_fwd_cb_nodelay, false);
2358}
2359
2360
2361/*
2362 * OOM notifier, but this only prints diagnostic information for the
2363 * current forward-progress test.
2364 */
2365static int rcutorture_oom_notify(struct notifier_block *self,
2366 unsigned long notused, void *nfreed)
2367{
2368 struct rcu_fwd *rfp;
2369
2370 mutex_lock(&rcu_fwd_mutex);
2371 rfp = rcu_fwds;
2372 if (!rfp) {
2373 mutex_unlock(&rcu_fwd_mutex);
2374 return NOTIFY_OK;
2375 }
2376 WARN(1, "%s invoked upon OOM during forward-progress testing.\n",
2377 __func__);
2378 rcu_torture_fwd_cb_hist(rfp);
2379 rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp->rcu_fwd_startat)) / 2);
2380 WRITE_ONCE(rcu_fwd_emergency_stop, true);
2381 smp_mb(); /* Emergency stop before free and wait to avoid hangs. */
2382 pr_info("%s: Freed %lu RCU callbacks.\n",
2383 __func__, rcu_torture_fwd_prog_cbfree(rfp));
2384 rcu_barrier();
2385 pr_info("%s: Freed %lu RCU callbacks.\n",
2386 __func__, rcu_torture_fwd_prog_cbfree(rfp));
2387 rcu_barrier();
2388 pr_info("%s: Freed %lu RCU callbacks.\n",
2389 __func__, rcu_torture_fwd_prog_cbfree(rfp));
2390 smp_mb(); /* Frees before return to avoid redoing OOM. */
2391 (*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */
2392 pr_info("%s returning after OOM processing.\n", __func__);
2393 mutex_unlock(&rcu_fwd_mutex);
2394 return NOTIFY_OK;
2395}
2396
2397static struct notifier_block rcutorture_oom_nb = {
2398 .notifier_call = rcutorture_oom_notify
2399};
2400
2401/* Carry out grace-period forward-progress testing. */
2402static int rcu_torture_fwd_prog(void *args)
2403{
2404 int oldnice = task_nice(current);
2405 struct rcu_fwd *rfp = args;
2406 int tested = 0;
2407 int tested_tries = 0;
2408
2409 VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started");
2410 rcu_bind_current_to_nocb();
2411 if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST))
2412 set_user_nice(current, MAX_NICE);
2413 do {
2414 schedule_timeout_interruptible(fwd_progress_holdoff * HZ);
2415 WRITE_ONCE(rcu_fwd_emergency_stop, false);
2416 if (!IS_ENABLED(CONFIG_TINY_RCU) ||
2417 rcu_inkernel_boot_has_ended())
2418 rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries);
2419 if (rcu_inkernel_boot_has_ended())
2420 rcu_torture_fwd_prog_cr(rfp);
2421
2422 /* Avoid slow periods, better to test when busy. */
2423 if (stutter_wait("rcu_torture_fwd_prog"))
2424 sched_set_normal(current, oldnice);
2425 } while (!torture_must_stop());
2426 /* Short runs might not contain a valid forward-progress attempt. */
2427 WARN_ON(!tested && tested_tries >= 5);
2428 pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries);
2429 torture_kthread_stopping("rcu_torture_fwd_prog");
2430 return 0;
2431}
2432
2433/* If forward-progress checking is requested and feasible, spawn the thread. */
2434static int __init rcu_torture_fwd_prog_init(void)
2435{
2436 struct rcu_fwd *rfp;
2437
2438 if (!fwd_progress)
2439 return 0; /* Not requested, so don't do it. */
2440 if ((!cur_ops->sync && !cur_ops->call) ||
2441 !cur_ops->stall_dur || cur_ops->stall_dur() <= 0 || cur_ops == &rcu_busted_ops) {
2442 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test");
2443 return 0;
2444 }
2445 if (stall_cpu > 0) {
2446 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing");
2447 if (IS_MODULE(CONFIG_RCU_TORTURE_TESTS))
2448 return -EINVAL; /* In module, can fail back to user. */
2449 WARN_ON(1); /* Make sure rcutorture notices conflict. */
2450 return 0;
2451 }
2452 if (fwd_progress_holdoff <= 0)
2453 fwd_progress_holdoff = 1;
2454 if (fwd_progress_div <= 0)
2455 fwd_progress_div = 4;
2456 rfp = kzalloc(sizeof(*rfp), GFP_KERNEL);
2457 if (!rfp)
2458 return -ENOMEM;
2459 spin_lock_init(&rfp->rcu_fwd_lock);
2460 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head;
2461 mutex_lock(&rcu_fwd_mutex);
2462 rcu_fwds = rfp;
2463 mutex_unlock(&rcu_fwd_mutex);
2464 register_oom_notifier(&rcutorture_oom_nb);
2465 return torture_create_kthread(rcu_torture_fwd_prog, rfp, fwd_prog_task);
2466}
2467
2468static void rcu_torture_fwd_prog_cleanup(void)
2469{
2470 struct rcu_fwd *rfp;
2471
2472 torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_task);
2473 rfp = rcu_fwds;
2474 mutex_lock(&rcu_fwd_mutex);
2475 rcu_fwds = NULL;
2476 mutex_unlock(&rcu_fwd_mutex);
2477 unregister_oom_notifier(&rcutorture_oom_nb);
2478 kfree(rfp);
2479}
2480
2481/* Callback function for RCU barrier testing. */
2482static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
2483{
2484 atomic_inc(&barrier_cbs_invoked);
2485}
2486
2487/* IPI handler to get callback posted on desired CPU, if online. */
2488static void rcu_torture_barrier1cb(void *rcu_void)
2489{
2490 struct rcu_head *rhp = rcu_void;
2491
2492 cur_ops->call(rhp, rcu_torture_barrier_cbf);
2493}
2494
2495/* kthread function to register callbacks used to test RCU barriers. */
2496static int rcu_torture_barrier_cbs(void *arg)
2497{
2498 long myid = (long)arg;
2499 bool lastphase = false;
2500 bool newphase;
2501 struct rcu_head rcu;
2502
2503 init_rcu_head_on_stack(&rcu);
2504 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
2505 set_user_nice(current, MAX_NICE);
2506 do {
2507 wait_event(barrier_cbs_wq[myid],
2508 (newphase =
2509 smp_load_acquire(&barrier_phase)) != lastphase ||
2510 torture_must_stop());
2511 lastphase = newphase;
2512 if (torture_must_stop())
2513 break;
2514 /*
2515 * The above smp_load_acquire() ensures barrier_phase load
2516 * is ordered before the following ->call().
2517 */
2518 if (smp_call_function_single(myid, rcu_torture_barrier1cb,
2519 &rcu, 1)) {
2520 // IPI failed, so use direct call from current CPU.
2521 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
2522 }
2523 if (atomic_dec_and_test(&barrier_cbs_count))
2524 wake_up(&barrier_wq);
2525 } while (!torture_must_stop());
2526 if (cur_ops->cb_barrier != NULL)
2527 cur_ops->cb_barrier();
2528 destroy_rcu_head_on_stack(&rcu);
2529 torture_kthread_stopping("rcu_torture_barrier_cbs");
2530 return 0;
2531}
2532
2533/* kthread function to drive and coordinate RCU barrier testing. */
2534static int rcu_torture_barrier(void *arg)
2535{
2536 int i;
2537
2538 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
2539 do {
2540 atomic_set(&barrier_cbs_invoked, 0);
2541 atomic_set(&barrier_cbs_count, n_barrier_cbs);
2542 /* Ensure barrier_phase ordered after prior assignments. */
2543 smp_store_release(&barrier_phase, !barrier_phase);
2544 for (i = 0; i < n_barrier_cbs; i++)
2545 wake_up(&barrier_cbs_wq[i]);
2546 wait_event(barrier_wq,
2547 atomic_read(&barrier_cbs_count) == 0 ||
2548 torture_must_stop());
2549 if (torture_must_stop())
2550 break;
2551 n_barrier_attempts++;
2552 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
2553 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
2554 n_rcu_torture_barrier_error++;
2555 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
2556 atomic_read(&barrier_cbs_invoked),
2557 n_barrier_cbs);
2558 WARN_ON(1);
2559 // Wait manually for the remaining callbacks
2560 i = 0;
2561 do {
2562 if (WARN_ON(i++ > HZ))
2563 i = INT_MIN;
2564 schedule_timeout_interruptible(1);
2565 cur_ops->cb_barrier();
2566 } while (atomic_read(&barrier_cbs_invoked) !=
2567 n_barrier_cbs &&
2568 !torture_must_stop());
2569 smp_mb(); // Can't trust ordering if broken.
2570 if (!torture_must_stop())
2571 pr_err("Recovered: barrier_cbs_invoked = %d\n",
2572 atomic_read(&barrier_cbs_invoked));
2573 } else {
2574 n_barrier_successes++;
2575 }
2576 schedule_timeout_interruptible(HZ / 10);
2577 } while (!torture_must_stop());
2578 torture_kthread_stopping("rcu_torture_barrier");
2579 return 0;
2580}
2581
2582/* Initialize RCU barrier testing. */
2583static int rcu_torture_barrier_init(void)
2584{
2585 int i;
2586 int ret;
2587
2588 if (n_barrier_cbs <= 0)
2589 return 0;
2590 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
2591 pr_alert("%s" TORTURE_FLAG
2592 " Call or barrier ops missing for %s,\n",
2593 torture_type, cur_ops->name);
2594 pr_alert("%s" TORTURE_FLAG
2595 " RCU barrier testing omitted from run.\n",
2596 torture_type);
2597 return 0;
2598 }
2599 atomic_set(&barrier_cbs_count, 0);
2600 atomic_set(&barrier_cbs_invoked, 0);
2601 barrier_cbs_tasks =
2602 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]),
2603 GFP_KERNEL);
2604 barrier_cbs_wq =
2605 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL);
2606 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
2607 return -ENOMEM;
2608 for (i = 0; i < n_barrier_cbs; i++) {
2609 init_waitqueue_head(&barrier_cbs_wq[i]);
2610 ret = torture_create_kthread(rcu_torture_barrier_cbs,
2611 (void *)(long)i,
2612 barrier_cbs_tasks[i]);
2613 if (ret)
2614 return ret;
2615 }
2616 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
2617}
2618
2619/* Clean up after RCU barrier testing. */
2620static void rcu_torture_barrier_cleanup(void)
2621{
2622 int i;
2623
2624 torture_stop_kthread(rcu_torture_barrier, barrier_task);
2625 if (barrier_cbs_tasks != NULL) {
2626 for (i = 0; i < n_barrier_cbs; i++)
2627 torture_stop_kthread(rcu_torture_barrier_cbs,
2628 barrier_cbs_tasks[i]);
2629 kfree(barrier_cbs_tasks);
2630 barrier_cbs_tasks = NULL;
2631 }
2632 if (barrier_cbs_wq != NULL) {
2633 kfree(barrier_cbs_wq);
2634 barrier_cbs_wq = NULL;
2635 }
2636}
2637
2638static bool rcu_torture_can_boost(void)
2639{
2640 static int boost_warn_once;
2641 int prio;
2642
2643 if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2)
2644 return false;
2645 if (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)
2646 return false;
2647
2648 prio = rcu_get_gp_kthreads_prio();
2649 if (!prio)
2650 return false;
2651
2652 if (prio < 2) {
2653 if (boost_warn_once == 1)
2654 return false;
2655
2656 pr_alert("%s: WARN: RCU kthread priority too low to test boosting. Skipping RCU boost test. Try passing rcutree.kthread_prio > 1 on the kernel command line.\n", KBUILD_MODNAME);
2657 boost_warn_once = 1;
2658 return false;
2659 }
2660
2661 return true;
2662}
2663
2664static bool read_exit_child_stop;
2665static bool read_exit_child_stopped;
2666static wait_queue_head_t read_exit_wq;
2667
2668// Child kthread which just does an rcutorture reader and exits.
2669static int rcu_torture_read_exit_child(void *trsp_in)
2670{
2671 struct torture_random_state *trsp = trsp_in;
2672
2673 set_user_nice(current, MAX_NICE);
2674 // Minimize time between reading and exiting.
2675 while (!kthread_should_stop())
2676 schedule_timeout_uninterruptible(1);
2677 (void)rcu_torture_one_read(trsp, -1);
2678 return 0;
2679}
2680
2681// Parent kthread which creates and destroys read-exit child kthreads.
2682static int rcu_torture_read_exit(void *unused)
2683{
2684 int count = 0;
2685 bool errexit = false;
2686 int i;
2687 struct task_struct *tsp;
2688 DEFINE_TORTURE_RANDOM(trs);
2689
2690 // Allocate and initialize.
2691 set_user_nice(current, MAX_NICE);
2692 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of test");
2693
2694 // Each pass through this loop does one read-exit episode.
2695 do {
2696 if (++count > read_exit_burst) {
2697 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: End of episode");
2698 rcu_barrier(); // Wait for task_struct free, avoid OOM.
2699 for (i = 0; i < read_exit_delay; i++) {
2700 schedule_timeout_uninterruptible(HZ);
2701 if (READ_ONCE(read_exit_child_stop))
2702 break;
2703 }
2704 if (!READ_ONCE(read_exit_child_stop))
2705 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of episode");
2706 count = 0;
2707 }
2708 if (READ_ONCE(read_exit_child_stop))
2709 break;
2710 // Spawn child.
2711 tsp = kthread_run(rcu_torture_read_exit_child,
2712 &trs, "%s",
2713 "rcu_torture_read_exit_child");
2714 if (IS_ERR(tsp)) {
2715 VERBOSE_TOROUT_ERRSTRING("out of memory");
2716 errexit = true;
2717 tsp = NULL;
2718 break;
2719 }
2720 cond_resched();
2721 kthread_stop(tsp);
2722 n_read_exits ++;
2723 stutter_wait("rcu_torture_read_exit");
2724 } while (!errexit && !READ_ONCE(read_exit_child_stop));
2725
2726 // Clean up and exit.
2727 smp_store_release(&read_exit_child_stopped, true); // After reaping.
2728 smp_mb(); // Store before wakeup.
2729 wake_up(&read_exit_wq);
2730 while (!torture_must_stop())
2731 schedule_timeout_uninterruptible(1);
2732 torture_kthread_stopping("rcu_torture_read_exit");
2733 return 0;
2734}
2735
2736static int rcu_torture_read_exit_init(void)
2737{
2738 if (read_exit_burst <= 0)
2739 return -EINVAL;
2740 init_waitqueue_head(&read_exit_wq);
2741 read_exit_child_stop = false;
2742 read_exit_child_stopped = false;
2743 return torture_create_kthread(rcu_torture_read_exit, NULL,
2744 read_exit_task);
2745}
2746
2747static void rcu_torture_read_exit_cleanup(void)
2748{
2749 if (!read_exit_task)
2750 return;
2751 WRITE_ONCE(read_exit_child_stop, true);
2752 smp_mb(); // Above write before wait.
2753 wait_event(read_exit_wq, smp_load_acquire(&read_exit_child_stopped));
2754 torture_stop_kthread(rcutorture_read_exit, read_exit_task);
2755}
2756
2757static enum cpuhp_state rcutor_hp;
2758
2759static void
2760rcu_torture_cleanup(void)
2761{
2762 int firsttime;
2763 int flags = 0;
2764 unsigned long gp_seq = 0;
2765 int i;
2766
2767 if (torture_cleanup_begin()) {
2768 if (cur_ops->cb_barrier != NULL)
2769 cur_ops->cb_barrier();
2770 return;
2771 }
2772 if (!cur_ops) {
2773 torture_cleanup_end();
2774 return;
2775 }
2776
2777 if (cur_ops->gp_kthread_dbg)
2778 cur_ops->gp_kthread_dbg();
2779 rcu_torture_read_exit_cleanup();
2780 rcu_torture_barrier_cleanup();
2781 rcu_torture_fwd_prog_cleanup();
2782 torture_stop_kthread(rcu_torture_stall, stall_task);
2783 torture_stop_kthread(rcu_torture_writer, writer_task);
2784
2785 if (nocb_tasks) {
2786 for (i = 0; i < nrealnocbers; i++)
2787 torture_stop_kthread(rcu_nocb_toggle, nocb_tasks[i]);
2788 kfree(nocb_tasks);
2789 nocb_tasks = NULL;
2790 }
2791
2792 if (reader_tasks) {
2793 for (i = 0; i < nrealreaders; i++)
2794 torture_stop_kthread(rcu_torture_reader,
2795 reader_tasks[i]);
2796 kfree(reader_tasks);
2797 reader_tasks = NULL;
2798 }
2799 kfree(rcu_torture_reader_mbchk);
2800 rcu_torture_reader_mbchk = NULL;
2801
2802 if (fakewriter_tasks) {
2803 for (i = 0; i < nfakewriters; i++)
2804 torture_stop_kthread(rcu_torture_fakewriter,
2805 fakewriter_tasks[i]);
2806 kfree(fakewriter_tasks);
2807 fakewriter_tasks = NULL;
2808 }
2809
2810 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq);
2811 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq);
2812 pr_alert("%s: End-test grace-period state: g%ld f%#x total-gps=%ld\n",
2813 cur_ops->name, (long)gp_seq, flags,
2814 rcutorture_seq_diff(gp_seq, start_gp_seq));
2815 torture_stop_kthread(rcu_torture_stats, stats_task);
2816 torture_stop_kthread(rcu_torture_fqs, fqs_task);
2817 if (rcu_torture_can_boost())
2818 cpuhp_remove_state(rcutor_hp);
2819
2820 /*
2821 * Wait for all RCU callbacks to fire, then do torture-type-specific
2822 * cleanup operations.
2823 */
2824 if (cur_ops->cb_barrier != NULL)
2825 cur_ops->cb_barrier();
2826 if (cur_ops->cleanup != NULL)
2827 cur_ops->cleanup();
2828
2829 rcu_torture_mem_dump_obj();
2830
2831 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
2832
2833 if (err_segs_recorded) {
2834 pr_alert("Failure/close-call rcutorture reader segments:\n");
2835 if (rt_read_nsegs == 0)
2836 pr_alert("\t: No segments recorded!!!\n");
2837 firsttime = 1;
2838 for (i = 0; i < rt_read_nsegs; i++) {
2839 pr_alert("\t%d: %#x ", i, err_segs[i].rt_readstate);
2840 if (err_segs[i].rt_delay_jiffies != 0) {
2841 pr_cont("%s%ldjiffies", firsttime ? "" : "+",
2842 err_segs[i].rt_delay_jiffies);
2843 firsttime = 0;
2844 }
2845 if (err_segs[i].rt_delay_ms != 0) {
2846 pr_cont("%s%ldms", firsttime ? "" : "+",
2847 err_segs[i].rt_delay_ms);
2848 firsttime = 0;
2849 }
2850 if (err_segs[i].rt_delay_us != 0) {
2851 pr_cont("%s%ldus", firsttime ? "" : "+",
2852 err_segs[i].rt_delay_us);
2853 firsttime = 0;
2854 }
2855 pr_cont("%s\n",
2856 err_segs[i].rt_preempted ? "preempted" : "");
2857
2858 }
2859 }
2860 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
2861 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
2862 else if (torture_onoff_failures())
2863 rcu_torture_print_module_parms(cur_ops,
2864 "End of test: RCU_HOTPLUG");
2865 else
2866 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
2867 torture_cleanup_end();
2868}
2869
2870#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
2871static void rcu_torture_leak_cb(struct rcu_head *rhp)
2872{
2873}
2874
2875static void rcu_torture_err_cb(struct rcu_head *rhp)
2876{
2877 /*
2878 * This -might- happen due to race conditions, but is unlikely.
2879 * The scenario that leads to this happening is that the
2880 * first of the pair of duplicate callbacks is queued,
2881 * someone else starts a grace period that includes that
2882 * callback, then the second of the pair must wait for the
2883 * next grace period. Unlikely, but can happen. If it
2884 * does happen, the debug-objects subsystem won't have splatted.
2885 */
2886 pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME);
2887}
2888#endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
2889
2890/*
2891 * Verify that double-free causes debug-objects to complain, but only
2892 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
2893 * cannot be carried out.
2894 */
2895static void rcu_test_debug_objects(void)
2896{
2897#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
2898 struct rcu_head rh1;
2899 struct rcu_head rh2;
2900 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
2901
2902 init_rcu_head_on_stack(&rh1);
2903 init_rcu_head_on_stack(&rh2);
2904 pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME);
2905
2906 /* Try to queue the rh2 pair of callbacks for the same grace period. */
2907 preempt_disable(); /* Prevent preemption from interrupting test. */
2908 rcu_read_lock(); /* Make it impossible to finish a grace period. */
2909 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
2910 local_irq_disable(); /* Make it harder to start a new grace period. */
2911 call_rcu(&rh2, rcu_torture_leak_cb);
2912 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
2913 if (rhp) {
2914 call_rcu(rhp, rcu_torture_leak_cb);
2915 call_rcu(rhp, rcu_torture_err_cb); /* Another duplicate callback. */
2916 }
2917 local_irq_enable();
2918 rcu_read_unlock();
2919 preempt_enable();
2920
2921 /* Wait for them all to get done so we can safely return. */
2922 rcu_barrier();
2923 pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME);
2924 destroy_rcu_head_on_stack(&rh1);
2925 destroy_rcu_head_on_stack(&rh2);
2926#else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
2927 pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME);
2928#endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
2929}
2930
2931static void rcutorture_sync(void)
2932{
2933 static unsigned long n;
2934
2935 if (cur_ops->sync && !(++n & 0xfff))
2936 cur_ops->sync();
2937}
2938
2939static int __init
2940rcu_torture_init(void)
2941{
2942 long i;
2943 int cpu;
2944 int firsterr = 0;
2945 int flags = 0;
2946 unsigned long gp_seq = 0;
2947 static struct rcu_torture_ops *torture_ops[] = {
2948 &rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops,
2949 &busted_srcud_ops, &tasks_ops, &tasks_rude_ops,
2950 &tasks_tracing_ops, &trivial_ops,
2951 };
2952
2953 if (!torture_init_begin(torture_type, verbose))
2954 return -EBUSY;
2955
2956 /* Process args and tell the world that the torturer is on the job. */
2957 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
2958 cur_ops = torture_ops[i];
2959 if (strcmp(torture_type, cur_ops->name) == 0)
2960 break;
2961 }
2962 if (i == ARRAY_SIZE(torture_ops)) {
2963 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
2964 torture_type);
2965 pr_alert("rcu-torture types:");
2966 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
2967 pr_cont(" %s", torture_ops[i]->name);
2968 pr_cont("\n");
2969 firsterr = -EINVAL;
2970 cur_ops = NULL;
2971 goto unwind;
2972 }
2973 if (cur_ops->fqs == NULL && fqs_duration != 0) {
2974 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
2975 fqs_duration = 0;
2976 }
2977 if (cur_ops->init)
2978 cur_ops->init();
2979
2980 if (nreaders >= 0) {
2981 nrealreaders = nreaders;
2982 } else {
2983 nrealreaders = num_online_cpus() - 2 - nreaders;
2984 if (nrealreaders <= 0)
2985 nrealreaders = 1;
2986 }
2987 rcu_torture_print_module_parms(cur_ops, "Start of test");
2988 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq);
2989 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq);
2990 start_gp_seq = gp_seq;
2991 pr_alert("%s: Start-test grace-period state: g%ld f%#x\n",
2992 cur_ops->name, (long)gp_seq, flags);
2993
2994 /* Set up the freelist. */
2995
2996 INIT_LIST_HEAD(&rcu_torture_freelist);
2997 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
2998 rcu_tortures[i].rtort_mbtest = 0;
2999 list_add_tail(&rcu_tortures[i].rtort_free,
3000 &rcu_torture_freelist);
3001 }
3002
3003 /* Initialize the statistics so that each run gets its own numbers. */
3004
3005 rcu_torture_current = NULL;
3006 rcu_torture_current_version = 0;
3007 atomic_set(&n_rcu_torture_alloc, 0);
3008 atomic_set(&n_rcu_torture_alloc_fail, 0);
3009 atomic_set(&n_rcu_torture_free, 0);
3010 atomic_set(&n_rcu_torture_mberror, 0);
3011 atomic_set(&n_rcu_torture_mbchk_fail, 0);
3012 atomic_set(&n_rcu_torture_mbchk_tries, 0);
3013 atomic_set(&n_rcu_torture_error, 0);
3014 n_rcu_torture_barrier_error = 0;
3015 n_rcu_torture_boost_ktrerror = 0;
3016 n_rcu_torture_boost_rterror = 0;
3017 n_rcu_torture_boost_failure = 0;
3018 n_rcu_torture_boosts = 0;
3019 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
3020 atomic_set(&rcu_torture_wcount[i], 0);
3021 for_each_possible_cpu(cpu) {
3022 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
3023 per_cpu(rcu_torture_count, cpu)[i] = 0;
3024 per_cpu(rcu_torture_batch, cpu)[i] = 0;
3025 }
3026 }
3027 err_segs_recorded = 0;
3028 rt_read_nsegs = 0;
3029
3030 /* Start up the kthreads. */
3031
3032 rcu_torture_write_types();
3033 firsterr = torture_create_kthread(rcu_torture_writer, NULL,
3034 writer_task);
3035 if (firsterr)
3036 goto unwind;
3037 if (nfakewriters > 0) {
3038 fakewriter_tasks = kcalloc(nfakewriters,
3039 sizeof(fakewriter_tasks[0]),
3040 GFP_KERNEL);
3041 if (fakewriter_tasks == NULL) {
3042 VERBOSE_TOROUT_ERRSTRING("out of memory");
3043 firsterr = -ENOMEM;
3044 goto unwind;
3045 }
3046 }
3047 for (i = 0; i < nfakewriters; i++) {
3048 firsterr = torture_create_kthread(rcu_torture_fakewriter,
3049 NULL, fakewriter_tasks[i]);
3050 if (firsterr)
3051 goto unwind;
3052 }
3053 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
3054 GFP_KERNEL);
3055 rcu_torture_reader_mbchk = kcalloc(nrealreaders, sizeof(*rcu_torture_reader_mbchk),
3056 GFP_KERNEL);
3057 if (!reader_tasks || !rcu_torture_reader_mbchk) {
3058 VERBOSE_TOROUT_ERRSTRING("out of memory");
3059 firsterr = -ENOMEM;
3060 goto unwind;
3061 }
3062 for (i = 0; i < nrealreaders; i++) {
3063 rcu_torture_reader_mbchk[i].rtc_chkrdr = -1;
3064 firsterr = torture_create_kthread(rcu_torture_reader, (void *)i,
3065 reader_tasks[i]);
3066 if (firsterr)
3067 goto unwind;
3068 }
3069 nrealnocbers = nocbs_nthreads;
3070 if (WARN_ON(nrealnocbers < 0))
3071 nrealnocbers = 1;
3072 if (WARN_ON(nocbs_toggle < 0))
3073 nocbs_toggle = HZ;
3074 if (nrealnocbers > 0) {
3075 nocb_tasks = kcalloc(nrealnocbers, sizeof(nocb_tasks[0]), GFP_KERNEL);
3076 if (nocb_tasks == NULL) {
3077 VERBOSE_TOROUT_ERRSTRING("out of memory");
3078 firsterr = -ENOMEM;
3079 goto unwind;
3080 }
3081 } else {
3082 nocb_tasks = NULL;
3083 }
3084 for (i = 0; i < nrealnocbers; i++) {
3085 firsterr = torture_create_kthread(rcu_nocb_toggle, NULL, nocb_tasks[i]);
3086 if (firsterr)
3087 goto unwind;
3088 }
3089 if (stat_interval > 0) {
3090 firsterr = torture_create_kthread(rcu_torture_stats, NULL,
3091 stats_task);
3092 if (firsterr)
3093 goto unwind;
3094 }
3095 if (test_no_idle_hz && shuffle_interval > 0) {
3096 firsterr = torture_shuffle_init(shuffle_interval * HZ);
3097 if (firsterr)
3098 goto unwind;
3099 }
3100 if (stutter < 0)
3101 stutter = 0;
3102 if (stutter) {
3103 int t;
3104
3105 t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ;
3106 firsterr = torture_stutter_init(stutter * HZ, t);
3107 if (firsterr)
3108 goto unwind;
3109 }
3110 if (fqs_duration < 0)
3111 fqs_duration = 0;
3112 if (fqs_duration) {
3113 /* Create the fqs thread */
3114 firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
3115 fqs_task);
3116 if (firsterr)
3117 goto unwind;
3118 }
3119 if (test_boost_interval < 1)
3120 test_boost_interval = 1;
3121 if (test_boost_duration < 2)
3122 test_boost_duration = 2;
3123 if (rcu_torture_can_boost()) {
3124
3125 boost_starttime = jiffies + test_boost_interval * HZ;
3126
3127 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE",
3128 rcutorture_booster_init,
3129 rcutorture_booster_cleanup);
3130 if (firsterr < 0)
3131 goto unwind;
3132 rcutor_hp = firsterr;
3133
3134 // Testing RCU priority boosting requires rcutorture do
3135 // some serious abuse. Counter this by running ksoftirqd
3136 // at higher priority.
3137 if (IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)) {
3138 for_each_online_cpu(cpu) {
3139 struct sched_param sp;
3140 struct task_struct *t;
3141
3142 t = per_cpu(ksoftirqd, cpu);
3143 WARN_ON_ONCE(!t);
3144 sp.sched_priority = 2;
3145 sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
3146 }
3147 }
3148 }
3149 shutdown_jiffies = jiffies + shutdown_secs * HZ;
3150 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
3151 if (firsterr)
3152 goto unwind;
3153 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval,
3154 rcutorture_sync);
3155 if (firsterr)
3156 goto unwind;
3157 firsterr = rcu_torture_stall_init();
3158 if (firsterr)
3159 goto unwind;
3160 firsterr = rcu_torture_fwd_prog_init();
3161 if (firsterr)
3162 goto unwind;
3163 firsterr = rcu_torture_barrier_init();
3164 if (firsterr)
3165 goto unwind;
3166 firsterr = rcu_torture_read_exit_init();
3167 if (firsterr)
3168 goto unwind;
3169 if (object_debug)
3170 rcu_test_debug_objects();
3171 torture_init_end();
3172 return 0;
3173
3174unwind:
3175 torture_init_end();
3176 rcu_torture_cleanup();
3177 if (shutdown_secs) {
3178 WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST));
3179 kernel_power_off();
3180 }
3181 return firsterr;
3182}
3183
3184module_init(rcu_torture_init);
3185module_exit(rcu_torture_cleanup);