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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/*
2 * Read-Copy Update module-based torture test facility
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, you can access it online at
16 * http://www.gnu.org/licenses/gpl-2.0.html.
17 *
18 * Copyright (C) IBM Corporation, 2005, 2006
19 *
20 * Authors: Paul E. McKenney <paulmck@us.ibm.com>
21 * Josh Triplett <josh@joshtriplett.org>
22 *
23 * See also: Documentation/RCU/torture.txt
24 */
25#include <linux/types.h>
26#include <linux/kernel.h>
27#include <linux/init.h>
28#include <linux/module.h>
29#include <linux/kthread.h>
30#include <linux/err.h>
31#include <linux/spinlock.h>
32#include <linux/smp.h>
33#include <linux/rcupdate.h>
34#include <linux/interrupt.h>
35#include <linux/sched/signal.h>
36#include <uapi/linux/sched/types.h>
37#include <linux/atomic.h>
38#include <linux/bitops.h>
39#include <linux/completion.h>
40#include <linux/moduleparam.h>
41#include <linux/percpu.h>
42#include <linux/notifier.h>
43#include <linux/reboot.h>
44#include <linux/freezer.h>
45#include <linux/cpu.h>
46#include <linux/delay.h>
47#include <linux/stat.h>
48#include <linux/srcu.h>
49#include <linux/slab.h>
50#include <linux/trace_clock.h>
51#include <asm/byteorder.h>
52#include <linux/torture.h>
53#include <linux/vmalloc.h>
54#include <linux/sched/debug.h>
55
56#include "rcu.h"
57
58MODULE_LICENSE("GPL");
59MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
60
61
62torture_param(int, cbflood_inter_holdoff, HZ,
63 "Holdoff between floods (jiffies)");
64torture_param(int, cbflood_intra_holdoff, 1,
65 "Holdoff between bursts (jiffies)");
66torture_param(int, cbflood_n_burst, 3, "# bursts in flood, zero to disable");
67torture_param(int, cbflood_n_per_burst, 20000,
68 "# callbacks per burst in flood");
69torture_param(int, fqs_duration, 0,
70 "Duration of fqs bursts (us), 0 to disable");
71torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
72torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
73torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
74torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
75torture_param(bool, gp_normal, false,
76 "Use normal (non-expedited) GP wait primitives");
77torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
78torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
79torture_param(int, n_barrier_cbs, 0,
80 "# of callbacks/kthreads for barrier testing");
81torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
82torture_param(int, nreaders, -1, "Number of RCU reader threads");
83torture_param(int, object_debug, 0,
84 "Enable debug-object double call_rcu() testing");
85torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
86torture_param(int, onoff_interval, 0,
87 "Time between CPU hotplugs (s), 0=disable");
88torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
89torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
90torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
91torture_param(int, stall_cpu_holdoff, 10,
92 "Time to wait before starting stall (s).");
93torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling.");
94torture_param(int, stat_interval, 60,
95 "Number of seconds between stats printk()s");
96torture_param(int, stutter, 5, "Number of seconds to run/halt test");
97torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
98torture_param(int, test_boost_duration, 4,
99 "Duration of each boost test, seconds.");
100torture_param(int, test_boost_interval, 7,
101 "Interval between boost tests, seconds.");
102torture_param(bool, test_no_idle_hz, true,
103 "Test support for tickless idle CPUs");
104torture_param(bool, verbose, true,
105 "Enable verbose debugging printk()s");
106
107static char *torture_type = "rcu";
108module_param(torture_type, charp, 0444);
109MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, ...)");
110
111static int nrealreaders;
112static int ncbflooders;
113static struct task_struct *writer_task;
114static struct task_struct **fakewriter_tasks;
115static struct task_struct **reader_tasks;
116static struct task_struct *stats_task;
117static struct task_struct **cbflood_task;
118static struct task_struct *fqs_task;
119static struct task_struct *boost_tasks[NR_CPUS];
120static struct task_struct *stall_task;
121static struct task_struct **barrier_cbs_tasks;
122static struct task_struct *barrier_task;
123
124#define RCU_TORTURE_PIPE_LEN 10
125
126struct rcu_torture {
127 struct rcu_head rtort_rcu;
128 int rtort_pipe_count;
129 struct list_head rtort_free;
130 int rtort_mbtest;
131};
132
133static LIST_HEAD(rcu_torture_freelist);
134static struct rcu_torture __rcu *rcu_torture_current;
135static unsigned long rcu_torture_current_version;
136static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
137static DEFINE_SPINLOCK(rcu_torture_lock);
138static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count);
139static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch);
140static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
141static atomic_t n_rcu_torture_alloc;
142static atomic_t n_rcu_torture_alloc_fail;
143static atomic_t n_rcu_torture_free;
144static atomic_t n_rcu_torture_mberror;
145static atomic_t n_rcu_torture_error;
146static long n_rcu_torture_barrier_error;
147static long n_rcu_torture_boost_ktrerror;
148static long n_rcu_torture_boost_rterror;
149static long n_rcu_torture_boost_failure;
150static long n_rcu_torture_boosts;
151static long n_rcu_torture_timers;
152static long n_barrier_attempts;
153static long n_barrier_successes;
154static atomic_long_t n_cbfloods;
155static struct list_head rcu_torture_removed;
156
157static int rcu_torture_writer_state;
158#define RTWS_FIXED_DELAY 0
159#define RTWS_DELAY 1
160#define RTWS_REPLACE 2
161#define RTWS_DEF_FREE 3
162#define RTWS_EXP_SYNC 4
163#define RTWS_COND_GET 5
164#define RTWS_COND_SYNC 6
165#define RTWS_SYNC 7
166#define RTWS_STUTTER 8
167#define RTWS_STOPPING 9
168static const char * const rcu_torture_writer_state_names[] = {
169 "RTWS_FIXED_DELAY",
170 "RTWS_DELAY",
171 "RTWS_REPLACE",
172 "RTWS_DEF_FREE",
173 "RTWS_EXP_SYNC",
174 "RTWS_COND_GET",
175 "RTWS_COND_SYNC",
176 "RTWS_SYNC",
177 "RTWS_STUTTER",
178 "RTWS_STOPPING",
179};
180
181static const char *rcu_torture_writer_state_getname(void)
182{
183 unsigned int i = READ_ONCE(rcu_torture_writer_state);
184
185 if (i >= ARRAY_SIZE(rcu_torture_writer_state_names))
186 return "???";
187 return rcu_torture_writer_state_names[i];
188}
189
190#if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
191#define rcu_can_boost() 1
192#else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
193#define rcu_can_boost() 0
194#endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
195
196#ifdef CONFIG_RCU_TRACE
197static u64 notrace rcu_trace_clock_local(void)
198{
199 u64 ts = trace_clock_local();
200
201 (void)do_div(ts, NSEC_PER_USEC);
202 return ts;
203}
204#else /* #ifdef CONFIG_RCU_TRACE */
205static u64 notrace rcu_trace_clock_local(void)
206{
207 return 0ULL;
208}
209#endif /* #else #ifdef CONFIG_RCU_TRACE */
210
211static unsigned long boost_starttime; /* jiffies of next boost test start. */
212static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
213 /* and boost task create/destroy. */
214static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
215static bool barrier_phase; /* Test phase. */
216static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
217static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
218static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
219
220/*
221 * Allocate an element from the rcu_tortures pool.
222 */
223static struct rcu_torture *
224rcu_torture_alloc(void)
225{
226 struct list_head *p;
227
228 spin_lock_bh(&rcu_torture_lock);
229 if (list_empty(&rcu_torture_freelist)) {
230 atomic_inc(&n_rcu_torture_alloc_fail);
231 spin_unlock_bh(&rcu_torture_lock);
232 return NULL;
233 }
234 atomic_inc(&n_rcu_torture_alloc);
235 p = rcu_torture_freelist.next;
236 list_del_init(p);
237 spin_unlock_bh(&rcu_torture_lock);
238 return container_of(p, struct rcu_torture, rtort_free);
239}
240
241/*
242 * Free an element to the rcu_tortures pool.
243 */
244static void
245rcu_torture_free(struct rcu_torture *p)
246{
247 atomic_inc(&n_rcu_torture_free);
248 spin_lock_bh(&rcu_torture_lock);
249 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
250 spin_unlock_bh(&rcu_torture_lock);
251}
252
253/*
254 * Operations vector for selecting different types of tests.
255 */
256
257struct rcu_torture_ops {
258 int ttype;
259 void (*init)(void);
260 void (*cleanup)(void);
261 int (*readlock)(void);
262 void (*read_delay)(struct torture_random_state *rrsp);
263 void (*readunlock)(int idx);
264 unsigned long (*started)(void);
265 unsigned long (*completed)(void);
266 void (*deferred_free)(struct rcu_torture *p);
267 void (*sync)(void);
268 void (*exp_sync)(void);
269 unsigned long (*get_state)(void);
270 void (*cond_sync)(unsigned long oldstate);
271 call_rcu_func_t call;
272 void (*cb_barrier)(void);
273 void (*fqs)(void);
274 void (*stats)(void);
275 int irq_capable;
276 int can_boost;
277 const char *name;
278};
279
280static struct rcu_torture_ops *cur_ops;
281
282/*
283 * Definitions for rcu torture testing.
284 */
285
286static int rcu_torture_read_lock(void) __acquires(RCU)
287{
288 rcu_read_lock();
289 return 0;
290}
291
292static void rcu_read_delay(struct torture_random_state *rrsp)
293{
294 unsigned long started;
295 unsigned long completed;
296 const unsigned long shortdelay_us = 200;
297 const unsigned long longdelay_ms = 50;
298 unsigned long long ts;
299
300 /* We want a short delay sometimes to make a reader delay the grace
301 * period, and we want a long delay occasionally to trigger
302 * force_quiescent_state. */
303
304 if (!(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) {
305 started = cur_ops->completed();
306 ts = rcu_trace_clock_local();
307 mdelay(longdelay_ms);
308 completed = cur_ops->completed();
309 do_trace_rcu_torture_read(cur_ops->name, NULL, ts,
310 started, completed);
311 }
312 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
313 udelay(shortdelay_us);
314 if (!preempt_count() &&
315 !(torture_random(rrsp) % (nrealreaders * 500)))
316 torture_preempt_schedule(); /* QS only if preemptible. */
317}
318
319static void rcu_torture_read_unlock(int idx) __releases(RCU)
320{
321 rcu_read_unlock();
322}
323
324/*
325 * Update callback in the pipe. This should be invoked after a grace period.
326 */
327static bool
328rcu_torture_pipe_update_one(struct rcu_torture *rp)
329{
330 int i;
331
332 i = rp->rtort_pipe_count;
333 if (i > RCU_TORTURE_PIPE_LEN)
334 i = RCU_TORTURE_PIPE_LEN;
335 atomic_inc(&rcu_torture_wcount[i]);
336 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
337 rp->rtort_mbtest = 0;
338 return true;
339 }
340 return false;
341}
342
343/*
344 * Update all callbacks in the pipe. Suitable for synchronous grace-period
345 * primitives.
346 */
347static void
348rcu_torture_pipe_update(struct rcu_torture *old_rp)
349{
350 struct rcu_torture *rp;
351 struct rcu_torture *rp1;
352
353 if (old_rp)
354 list_add(&old_rp->rtort_free, &rcu_torture_removed);
355 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
356 if (rcu_torture_pipe_update_one(rp)) {
357 list_del(&rp->rtort_free);
358 rcu_torture_free(rp);
359 }
360 }
361}
362
363static void
364rcu_torture_cb(struct rcu_head *p)
365{
366 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
367
368 if (torture_must_stop_irq()) {
369 /* Test is ending, just drop callbacks on the floor. */
370 /* The next initialization will pick up the pieces. */
371 return;
372 }
373 if (rcu_torture_pipe_update_one(rp))
374 rcu_torture_free(rp);
375 else
376 cur_ops->deferred_free(rp);
377}
378
379static unsigned long rcu_no_completed(void)
380{
381 return 0;
382}
383
384static void rcu_torture_deferred_free(struct rcu_torture *p)
385{
386 call_rcu(&p->rtort_rcu, rcu_torture_cb);
387}
388
389static void rcu_sync_torture_init(void)
390{
391 INIT_LIST_HEAD(&rcu_torture_removed);
392}
393
394static struct rcu_torture_ops rcu_ops = {
395 .ttype = RCU_FLAVOR,
396 .init = rcu_sync_torture_init,
397 .readlock = rcu_torture_read_lock,
398 .read_delay = rcu_read_delay,
399 .readunlock = rcu_torture_read_unlock,
400 .started = rcu_batches_started,
401 .completed = rcu_batches_completed,
402 .deferred_free = rcu_torture_deferred_free,
403 .sync = synchronize_rcu,
404 .exp_sync = synchronize_rcu_expedited,
405 .get_state = get_state_synchronize_rcu,
406 .cond_sync = cond_synchronize_rcu,
407 .call = call_rcu,
408 .cb_barrier = rcu_barrier,
409 .fqs = rcu_force_quiescent_state,
410 .stats = NULL,
411 .irq_capable = 1,
412 .can_boost = rcu_can_boost(),
413 .name = "rcu"
414};
415
416/*
417 * Definitions for rcu_bh torture testing.
418 */
419
420static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
421{
422 rcu_read_lock_bh();
423 return 0;
424}
425
426static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
427{
428 rcu_read_unlock_bh();
429}
430
431static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
432{
433 call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
434}
435
436static struct rcu_torture_ops rcu_bh_ops = {
437 .ttype = RCU_BH_FLAVOR,
438 .init = rcu_sync_torture_init,
439 .readlock = rcu_bh_torture_read_lock,
440 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
441 .readunlock = rcu_bh_torture_read_unlock,
442 .started = rcu_batches_started_bh,
443 .completed = rcu_batches_completed_bh,
444 .deferred_free = rcu_bh_torture_deferred_free,
445 .sync = synchronize_rcu_bh,
446 .exp_sync = synchronize_rcu_bh_expedited,
447 .call = call_rcu_bh,
448 .cb_barrier = rcu_barrier_bh,
449 .fqs = rcu_bh_force_quiescent_state,
450 .stats = NULL,
451 .irq_capable = 1,
452 .name = "rcu_bh"
453};
454
455/*
456 * Don't even think about trying any of these in real life!!!
457 * The names includes "busted", and they really means it!
458 * The only purpose of these functions is to provide a buggy RCU
459 * implementation to make sure that rcutorture correctly emits
460 * buggy-RCU error messages.
461 */
462static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
463{
464 /* This is a deliberate bug for testing purposes only! */
465 rcu_torture_cb(&p->rtort_rcu);
466}
467
468static void synchronize_rcu_busted(void)
469{
470 /* This is a deliberate bug for testing purposes only! */
471}
472
473static void
474call_rcu_busted(struct rcu_head *head, rcu_callback_t func)
475{
476 /* This is a deliberate bug for testing purposes only! */
477 func(head);
478}
479
480static struct rcu_torture_ops rcu_busted_ops = {
481 .ttype = INVALID_RCU_FLAVOR,
482 .init = rcu_sync_torture_init,
483 .readlock = rcu_torture_read_lock,
484 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
485 .readunlock = rcu_torture_read_unlock,
486 .started = rcu_no_completed,
487 .completed = rcu_no_completed,
488 .deferred_free = rcu_busted_torture_deferred_free,
489 .sync = synchronize_rcu_busted,
490 .exp_sync = synchronize_rcu_busted,
491 .call = call_rcu_busted,
492 .cb_barrier = NULL,
493 .fqs = NULL,
494 .stats = NULL,
495 .irq_capable = 1,
496 .name = "busted"
497};
498
499/*
500 * Definitions for srcu torture testing.
501 */
502
503DEFINE_STATIC_SRCU(srcu_ctl);
504static struct srcu_struct srcu_ctld;
505static struct srcu_struct *srcu_ctlp = &srcu_ctl;
506
507static int srcu_torture_read_lock(void) __acquires(srcu_ctlp)
508{
509 return srcu_read_lock(srcu_ctlp);
510}
511
512static void srcu_read_delay(struct torture_random_state *rrsp)
513{
514 long delay;
515 const long uspertick = 1000000 / HZ;
516 const long longdelay = 10;
517
518 /* We want there to be long-running readers, but not all the time. */
519
520 delay = torture_random(rrsp) %
521 (nrealreaders * 2 * longdelay * uspertick);
522 if (!delay && in_task())
523 schedule_timeout_interruptible(longdelay);
524 else
525 rcu_read_delay(rrsp);
526}
527
528static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp)
529{
530 srcu_read_unlock(srcu_ctlp, idx);
531}
532
533static unsigned long srcu_torture_completed(void)
534{
535 return srcu_batches_completed(srcu_ctlp);
536}
537
538static void srcu_torture_deferred_free(struct rcu_torture *rp)
539{
540 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
541}
542
543static void srcu_torture_synchronize(void)
544{
545 synchronize_srcu(srcu_ctlp);
546}
547
548static void srcu_torture_call(struct rcu_head *head,
549 rcu_callback_t func)
550{
551 call_srcu(srcu_ctlp, head, func);
552}
553
554static void srcu_torture_barrier(void)
555{
556 srcu_barrier(srcu_ctlp);
557}
558
559static void srcu_torture_stats(void)
560{
561 srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG);
562}
563
564static void srcu_torture_synchronize_expedited(void)
565{
566 synchronize_srcu_expedited(srcu_ctlp);
567}
568
569static struct rcu_torture_ops srcu_ops = {
570 .ttype = SRCU_FLAVOR,
571 .init = rcu_sync_torture_init,
572 .readlock = srcu_torture_read_lock,
573 .read_delay = srcu_read_delay,
574 .readunlock = srcu_torture_read_unlock,
575 .started = NULL,
576 .completed = srcu_torture_completed,
577 .deferred_free = srcu_torture_deferred_free,
578 .sync = srcu_torture_synchronize,
579 .exp_sync = srcu_torture_synchronize_expedited,
580 .call = srcu_torture_call,
581 .cb_barrier = srcu_torture_barrier,
582 .stats = srcu_torture_stats,
583 .irq_capable = 1,
584 .name = "srcu"
585};
586
587static void srcu_torture_init(void)
588{
589 rcu_sync_torture_init();
590 WARN_ON(init_srcu_struct(&srcu_ctld));
591 srcu_ctlp = &srcu_ctld;
592}
593
594static void srcu_torture_cleanup(void)
595{
596 cleanup_srcu_struct(&srcu_ctld);
597 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
598}
599
600/* As above, but dynamically allocated. */
601static struct rcu_torture_ops srcud_ops = {
602 .ttype = SRCU_FLAVOR,
603 .init = srcu_torture_init,
604 .cleanup = srcu_torture_cleanup,
605 .readlock = srcu_torture_read_lock,
606 .read_delay = srcu_read_delay,
607 .readunlock = srcu_torture_read_unlock,
608 .started = NULL,
609 .completed = srcu_torture_completed,
610 .deferred_free = srcu_torture_deferred_free,
611 .sync = srcu_torture_synchronize,
612 .exp_sync = srcu_torture_synchronize_expedited,
613 .call = srcu_torture_call,
614 .cb_barrier = srcu_torture_barrier,
615 .stats = srcu_torture_stats,
616 .irq_capable = 1,
617 .name = "srcud"
618};
619
620/*
621 * Definitions for sched torture testing.
622 */
623
624static int sched_torture_read_lock(void)
625{
626 preempt_disable();
627 return 0;
628}
629
630static void sched_torture_read_unlock(int idx)
631{
632 preempt_enable();
633}
634
635static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
636{
637 call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
638}
639
640static struct rcu_torture_ops sched_ops = {
641 .ttype = RCU_SCHED_FLAVOR,
642 .init = rcu_sync_torture_init,
643 .readlock = sched_torture_read_lock,
644 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
645 .readunlock = sched_torture_read_unlock,
646 .started = rcu_batches_started_sched,
647 .completed = rcu_batches_completed_sched,
648 .deferred_free = rcu_sched_torture_deferred_free,
649 .sync = synchronize_sched,
650 .exp_sync = synchronize_sched_expedited,
651 .get_state = get_state_synchronize_sched,
652 .cond_sync = cond_synchronize_sched,
653 .call = call_rcu_sched,
654 .cb_barrier = rcu_barrier_sched,
655 .fqs = rcu_sched_force_quiescent_state,
656 .stats = NULL,
657 .irq_capable = 1,
658 .name = "sched"
659};
660
661/*
662 * Definitions for RCU-tasks torture testing.
663 */
664
665static int tasks_torture_read_lock(void)
666{
667 return 0;
668}
669
670static void tasks_torture_read_unlock(int idx)
671{
672}
673
674static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
675{
676 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
677}
678
679static struct rcu_torture_ops tasks_ops = {
680 .ttype = RCU_TASKS_FLAVOR,
681 .init = rcu_sync_torture_init,
682 .readlock = tasks_torture_read_lock,
683 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
684 .readunlock = tasks_torture_read_unlock,
685 .started = rcu_no_completed,
686 .completed = rcu_no_completed,
687 .deferred_free = rcu_tasks_torture_deferred_free,
688 .sync = synchronize_rcu_tasks,
689 .exp_sync = synchronize_rcu_tasks,
690 .call = call_rcu_tasks,
691 .cb_barrier = rcu_barrier_tasks,
692 .fqs = NULL,
693 .stats = NULL,
694 .irq_capable = 1,
695 .name = "tasks"
696};
697
698static bool __maybe_unused torturing_tasks(void)
699{
700 return cur_ops == &tasks_ops;
701}
702
703/*
704 * RCU torture priority-boost testing. Runs one real-time thread per
705 * CPU for moderate bursts, repeatedly registering RCU callbacks and
706 * spinning waiting for them to be invoked. If a given callback takes
707 * too long to be invoked, we assume that priority inversion has occurred.
708 */
709
710struct rcu_boost_inflight {
711 struct rcu_head rcu;
712 int inflight;
713};
714
715static void rcu_torture_boost_cb(struct rcu_head *head)
716{
717 struct rcu_boost_inflight *rbip =
718 container_of(head, struct rcu_boost_inflight, rcu);
719
720 /* Ensure RCU-core accesses precede clearing ->inflight */
721 smp_store_release(&rbip->inflight, 0);
722}
723
724static int rcu_torture_boost(void *arg)
725{
726 unsigned long call_rcu_time;
727 unsigned long endtime;
728 unsigned long oldstarttime;
729 struct rcu_boost_inflight rbi = { .inflight = 0 };
730 struct sched_param sp;
731
732 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
733
734 /* Set real-time priority. */
735 sp.sched_priority = 1;
736 if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
737 VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!");
738 n_rcu_torture_boost_rterror++;
739 }
740
741 init_rcu_head_on_stack(&rbi.rcu);
742 /* Each pass through the following loop does one boost-test cycle. */
743 do {
744 /* Wait for the next test interval. */
745 oldstarttime = boost_starttime;
746 while (ULONG_CMP_LT(jiffies, oldstarttime)) {
747 schedule_timeout_interruptible(oldstarttime - jiffies);
748 stutter_wait("rcu_torture_boost");
749 if (torture_must_stop())
750 goto checkwait;
751 }
752
753 /* Do one boost-test interval. */
754 endtime = oldstarttime + test_boost_duration * HZ;
755 call_rcu_time = jiffies;
756 while (ULONG_CMP_LT(jiffies, endtime)) {
757 /* If we don't have a callback in flight, post one. */
758 if (!smp_load_acquire(&rbi.inflight)) {
759 /* RCU core before ->inflight = 1. */
760 smp_store_release(&rbi.inflight, 1);
761 call_rcu(&rbi.rcu, rcu_torture_boost_cb);
762 if (jiffies - call_rcu_time >
763 test_boost_duration * HZ - HZ / 2) {
764 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
765 n_rcu_torture_boost_failure++;
766 }
767 call_rcu_time = jiffies;
768 }
769 stutter_wait("rcu_torture_boost");
770 if (torture_must_stop())
771 goto checkwait;
772 }
773
774 /*
775 * Set the start time of the next test interval.
776 * Yes, this is vulnerable to long delays, but such
777 * delays simply cause a false negative for the next
778 * interval. Besides, we are running at RT priority,
779 * so delays should be relatively rare.
780 */
781 while (oldstarttime == boost_starttime &&
782 !kthread_should_stop()) {
783 if (mutex_trylock(&boost_mutex)) {
784 boost_starttime = jiffies +
785 test_boost_interval * HZ;
786 n_rcu_torture_boosts++;
787 mutex_unlock(&boost_mutex);
788 break;
789 }
790 schedule_timeout_uninterruptible(1);
791 }
792
793 /* Go do the stutter. */
794checkwait: stutter_wait("rcu_torture_boost");
795 } while (!torture_must_stop());
796
797 /* Clean up and exit. */
798 while (!kthread_should_stop() || smp_load_acquire(&rbi.inflight)) {
799 torture_shutdown_absorb("rcu_torture_boost");
800 schedule_timeout_uninterruptible(1);
801 }
802 destroy_rcu_head_on_stack(&rbi.rcu);
803 torture_kthread_stopping("rcu_torture_boost");
804 return 0;
805}
806
807static void rcu_torture_cbflood_cb(struct rcu_head *rhp)
808{
809}
810
811/*
812 * RCU torture callback-flood kthread. Repeatedly induces bursts of calls
813 * to call_rcu() or analogous, increasing the probability of occurrence
814 * of callback-overflow corner cases.
815 */
816static int
817rcu_torture_cbflood(void *arg)
818{
819 int err = 1;
820 int i;
821 int j;
822 struct rcu_head *rhp;
823
824 if (cbflood_n_per_burst > 0 &&
825 cbflood_inter_holdoff > 0 &&
826 cbflood_intra_holdoff > 0 &&
827 cur_ops->call &&
828 cur_ops->cb_barrier) {
829 rhp = vmalloc(sizeof(*rhp) *
830 cbflood_n_burst * cbflood_n_per_burst);
831 err = !rhp;
832 }
833 if (err) {
834 VERBOSE_TOROUT_STRING("rcu_torture_cbflood disabled: Bad args or OOM");
835 goto wait_for_stop;
836 }
837 VERBOSE_TOROUT_STRING("rcu_torture_cbflood task started");
838 do {
839 schedule_timeout_interruptible(cbflood_inter_holdoff);
840 atomic_long_inc(&n_cbfloods);
841 WARN_ON(signal_pending(current));
842 for (i = 0; i < cbflood_n_burst; i++) {
843 for (j = 0; j < cbflood_n_per_burst; j++) {
844 cur_ops->call(&rhp[i * cbflood_n_per_burst + j],
845 rcu_torture_cbflood_cb);
846 }
847 schedule_timeout_interruptible(cbflood_intra_holdoff);
848 WARN_ON(signal_pending(current));
849 }
850 cur_ops->cb_barrier();
851 stutter_wait("rcu_torture_cbflood");
852 } while (!torture_must_stop());
853 vfree(rhp);
854wait_for_stop:
855 torture_kthread_stopping("rcu_torture_cbflood");
856 return 0;
857}
858
859/*
860 * RCU torture force-quiescent-state kthread. Repeatedly induces
861 * bursts of calls to force_quiescent_state(), increasing the probability
862 * of occurrence of some important types of race conditions.
863 */
864static int
865rcu_torture_fqs(void *arg)
866{
867 unsigned long fqs_resume_time;
868 int fqs_burst_remaining;
869
870 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
871 do {
872 fqs_resume_time = jiffies + fqs_stutter * HZ;
873 while (ULONG_CMP_LT(jiffies, fqs_resume_time) &&
874 !kthread_should_stop()) {
875 schedule_timeout_interruptible(1);
876 }
877 fqs_burst_remaining = fqs_duration;
878 while (fqs_burst_remaining > 0 &&
879 !kthread_should_stop()) {
880 cur_ops->fqs();
881 udelay(fqs_holdoff);
882 fqs_burst_remaining -= fqs_holdoff;
883 }
884 stutter_wait("rcu_torture_fqs");
885 } while (!torture_must_stop());
886 torture_kthread_stopping("rcu_torture_fqs");
887 return 0;
888}
889
890/*
891 * RCU torture writer kthread. Repeatedly substitutes a new structure
892 * for that pointed to by rcu_torture_current, freeing the old structure
893 * after a series of grace periods (the "pipeline").
894 */
895static int
896rcu_torture_writer(void *arg)
897{
898 bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
899 int expediting = 0;
900 unsigned long gp_snap;
901 bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal;
902 bool gp_sync1 = gp_sync;
903 int i;
904 struct rcu_torture *rp;
905 struct rcu_torture *old_rp;
906 static DEFINE_TORTURE_RANDOM(rand);
907 int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC,
908 RTWS_COND_GET, RTWS_SYNC };
909 int nsynctypes = 0;
910
911 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
912 if (!can_expedite)
913 pr_alert("%s" TORTURE_FLAG
914 " GP expediting controlled from boot/sysfs for %s.\n",
915 torture_type, cur_ops->name);
916
917 /* Initialize synctype[] array. If none set, take default. */
918 if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync1)
919 gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true;
920 if (gp_cond1 && cur_ops->get_state && cur_ops->cond_sync) {
921 synctype[nsynctypes++] = RTWS_COND_GET;
922 pr_info("%s: Testing conditional GPs.\n", __func__);
923 } else if (gp_cond && (!cur_ops->get_state || !cur_ops->cond_sync)) {
924 pr_alert("%s: gp_cond without primitives.\n", __func__);
925 }
926 if (gp_exp1 && cur_ops->exp_sync) {
927 synctype[nsynctypes++] = RTWS_EXP_SYNC;
928 pr_info("%s: Testing expedited GPs.\n", __func__);
929 } else if (gp_exp && !cur_ops->exp_sync) {
930 pr_alert("%s: gp_exp without primitives.\n", __func__);
931 }
932 if (gp_normal1 && cur_ops->deferred_free) {
933 synctype[nsynctypes++] = RTWS_DEF_FREE;
934 pr_info("%s: Testing asynchronous GPs.\n", __func__);
935 } else if (gp_normal && !cur_ops->deferred_free) {
936 pr_alert("%s: gp_normal without primitives.\n", __func__);
937 }
938 if (gp_sync1 && cur_ops->sync) {
939 synctype[nsynctypes++] = RTWS_SYNC;
940 pr_info("%s: Testing normal GPs.\n", __func__);
941 } else if (gp_sync && !cur_ops->sync) {
942 pr_alert("%s: gp_sync without primitives.\n", __func__);
943 }
944 if (WARN_ONCE(nsynctypes == 0,
945 "rcu_torture_writer: No update-side primitives.\n")) {
946 /*
947 * No updates primitives, so don't try updating.
948 * The resulting test won't be testing much, hence the
949 * above WARN_ONCE().
950 */
951 rcu_torture_writer_state = RTWS_STOPPING;
952 torture_kthread_stopping("rcu_torture_writer");
953 }
954
955 do {
956 rcu_torture_writer_state = RTWS_FIXED_DELAY;
957 schedule_timeout_uninterruptible(1);
958 rp = rcu_torture_alloc();
959 if (rp == NULL)
960 continue;
961 rp->rtort_pipe_count = 0;
962 rcu_torture_writer_state = RTWS_DELAY;
963 udelay(torture_random(&rand) & 0x3ff);
964 rcu_torture_writer_state = RTWS_REPLACE;
965 old_rp = rcu_dereference_check(rcu_torture_current,
966 current == writer_task);
967 rp->rtort_mbtest = 1;
968 rcu_assign_pointer(rcu_torture_current, rp);
969 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
970 if (old_rp) {
971 i = old_rp->rtort_pipe_count;
972 if (i > RCU_TORTURE_PIPE_LEN)
973 i = RCU_TORTURE_PIPE_LEN;
974 atomic_inc(&rcu_torture_wcount[i]);
975 old_rp->rtort_pipe_count++;
976 switch (synctype[torture_random(&rand) % nsynctypes]) {
977 case RTWS_DEF_FREE:
978 rcu_torture_writer_state = RTWS_DEF_FREE;
979 cur_ops->deferred_free(old_rp);
980 break;
981 case RTWS_EXP_SYNC:
982 rcu_torture_writer_state = RTWS_EXP_SYNC;
983 cur_ops->exp_sync();
984 rcu_torture_pipe_update(old_rp);
985 break;
986 case RTWS_COND_GET:
987 rcu_torture_writer_state = RTWS_COND_GET;
988 gp_snap = cur_ops->get_state();
989 i = torture_random(&rand) % 16;
990 if (i != 0)
991 schedule_timeout_interruptible(i);
992 udelay(torture_random(&rand) % 1000);
993 rcu_torture_writer_state = RTWS_COND_SYNC;
994 cur_ops->cond_sync(gp_snap);
995 rcu_torture_pipe_update(old_rp);
996 break;
997 case RTWS_SYNC:
998 rcu_torture_writer_state = RTWS_SYNC;
999 cur_ops->sync();
1000 rcu_torture_pipe_update(old_rp);
1001 break;
1002 default:
1003 WARN_ON_ONCE(1);
1004 break;
1005 }
1006 }
1007 rcutorture_record_progress(++rcu_torture_current_version);
1008 /* Cycle through nesting levels of rcu_expedite_gp() calls. */
1009 if (can_expedite &&
1010 !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
1011 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
1012 if (expediting >= 0)
1013 rcu_expedite_gp();
1014 else
1015 rcu_unexpedite_gp();
1016 if (++expediting > 3)
1017 expediting = -expediting;
1018 } else if (!can_expedite) { /* Disabled during boot, recheck. */
1019 can_expedite = !rcu_gp_is_expedited() &&
1020 !rcu_gp_is_normal();
1021 }
1022 rcu_torture_writer_state = RTWS_STUTTER;
1023 stutter_wait("rcu_torture_writer");
1024 } while (!torture_must_stop());
1025 /* Reset expediting back to unexpedited. */
1026 if (expediting > 0)
1027 expediting = -expediting;
1028 while (can_expedite && expediting++ < 0)
1029 rcu_unexpedite_gp();
1030 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
1031 if (!can_expedite)
1032 pr_alert("%s" TORTURE_FLAG
1033 " Dynamic grace-period expediting was disabled.\n",
1034 torture_type);
1035 rcu_torture_writer_state = RTWS_STOPPING;
1036 torture_kthread_stopping("rcu_torture_writer");
1037 return 0;
1038}
1039
1040/*
1041 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
1042 * delay between calls.
1043 */
1044static int
1045rcu_torture_fakewriter(void *arg)
1046{
1047 DEFINE_TORTURE_RANDOM(rand);
1048
1049 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1050 set_user_nice(current, MAX_NICE);
1051
1052 do {
1053 schedule_timeout_uninterruptible(1 + torture_random(&rand)%10);
1054 udelay(torture_random(&rand) & 0x3ff);
1055 if (cur_ops->cb_barrier != NULL &&
1056 torture_random(&rand) % (nfakewriters * 8) == 0) {
1057 cur_ops->cb_barrier();
1058 } else if (gp_normal == gp_exp) {
1059 if (cur_ops->sync && torture_random(&rand) & 0x80)
1060 cur_ops->sync();
1061 else if (cur_ops->exp_sync)
1062 cur_ops->exp_sync();
1063 } else if (gp_normal && cur_ops->sync) {
1064 cur_ops->sync();
1065 } else if (cur_ops->exp_sync) {
1066 cur_ops->exp_sync();
1067 }
1068 stutter_wait("rcu_torture_fakewriter");
1069 } while (!torture_must_stop());
1070
1071 torture_kthread_stopping("rcu_torture_fakewriter");
1072 return 0;
1073}
1074
1075static void rcu_torture_timer_cb(struct rcu_head *rhp)
1076{
1077 kfree(rhp);
1078}
1079
1080/*
1081 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
1082 * incrementing the corresponding element of the pipeline array. The
1083 * counter in the element should never be greater than 1, otherwise, the
1084 * RCU implementation is broken.
1085 */
1086static void rcu_torture_timer(struct timer_list *unused)
1087{
1088 int idx;
1089 unsigned long started;
1090 unsigned long completed;
1091 static DEFINE_TORTURE_RANDOM(rand);
1092 static DEFINE_SPINLOCK(rand_lock);
1093 struct rcu_torture *p;
1094 int pipe_count;
1095 unsigned long long ts;
1096
1097 idx = cur_ops->readlock();
1098 if (cur_ops->started)
1099 started = cur_ops->started();
1100 else
1101 started = cur_ops->completed();
1102 ts = rcu_trace_clock_local();
1103 p = rcu_dereference_check(rcu_torture_current,
1104 rcu_read_lock_bh_held() ||
1105 rcu_read_lock_sched_held() ||
1106 srcu_read_lock_held(srcu_ctlp) ||
1107 torturing_tasks());
1108 if (p == NULL) {
1109 /* Leave because rcu_torture_writer is not yet underway */
1110 cur_ops->readunlock(idx);
1111 return;
1112 }
1113 if (p->rtort_mbtest == 0)
1114 atomic_inc(&n_rcu_torture_mberror);
1115 spin_lock(&rand_lock);
1116 cur_ops->read_delay(&rand);
1117 n_rcu_torture_timers++;
1118 spin_unlock(&rand_lock);
1119 preempt_disable();
1120 pipe_count = p->rtort_pipe_count;
1121 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1122 /* Should not happen, but... */
1123 pipe_count = RCU_TORTURE_PIPE_LEN;
1124 }
1125 completed = cur_ops->completed();
1126 if (pipe_count > 1) {
1127 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, ts,
1128 started, completed);
1129 rcu_ftrace_dump(DUMP_ALL);
1130 }
1131 __this_cpu_inc(rcu_torture_count[pipe_count]);
1132 completed = completed - started;
1133 if (cur_ops->started)
1134 completed++;
1135 if (completed > RCU_TORTURE_PIPE_LEN) {
1136 /* Should not happen, but... */
1137 completed = RCU_TORTURE_PIPE_LEN;
1138 }
1139 __this_cpu_inc(rcu_torture_batch[completed]);
1140 preempt_enable();
1141 cur_ops->readunlock(idx);
1142
1143 /* Test call_rcu() invocation from interrupt handler. */
1144 if (cur_ops->call) {
1145 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT);
1146
1147 if (rhp)
1148 cur_ops->call(rhp, rcu_torture_timer_cb);
1149 }
1150}
1151
1152/*
1153 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
1154 * incrementing the corresponding element of the pipeline array. The
1155 * counter in the element should never be greater than 1, otherwise, the
1156 * RCU implementation is broken.
1157 */
1158static int
1159rcu_torture_reader(void *arg)
1160{
1161 unsigned long started;
1162 unsigned long completed;
1163 int idx;
1164 DEFINE_TORTURE_RANDOM(rand);
1165 struct rcu_torture *p;
1166 int pipe_count;
1167 struct timer_list t;
1168 unsigned long long ts;
1169
1170 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
1171 set_user_nice(current, MAX_NICE);
1172 if (irqreader && cur_ops->irq_capable)
1173 timer_setup_on_stack(&t, rcu_torture_timer, 0);
1174
1175 do {
1176 if (irqreader && cur_ops->irq_capable) {
1177 if (!timer_pending(&t))
1178 mod_timer(&t, jiffies + 1);
1179 }
1180 idx = cur_ops->readlock();
1181 if (cur_ops->started)
1182 started = cur_ops->started();
1183 else
1184 started = cur_ops->completed();
1185 ts = rcu_trace_clock_local();
1186 p = rcu_dereference_check(rcu_torture_current,
1187 rcu_read_lock_bh_held() ||
1188 rcu_read_lock_sched_held() ||
1189 srcu_read_lock_held(srcu_ctlp) ||
1190 torturing_tasks());
1191 if (p == NULL) {
1192 /* Wait for rcu_torture_writer to get underway */
1193 cur_ops->readunlock(idx);
1194 schedule_timeout_interruptible(HZ);
1195 continue;
1196 }
1197 if (p->rtort_mbtest == 0)
1198 atomic_inc(&n_rcu_torture_mberror);
1199 cur_ops->read_delay(&rand);
1200 preempt_disable();
1201 pipe_count = p->rtort_pipe_count;
1202 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1203 /* Should not happen, but... */
1204 pipe_count = RCU_TORTURE_PIPE_LEN;
1205 }
1206 completed = cur_ops->completed();
1207 if (pipe_count > 1) {
1208 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
1209 ts, started, completed);
1210 rcu_ftrace_dump(DUMP_ALL);
1211 }
1212 __this_cpu_inc(rcu_torture_count[pipe_count]);
1213 completed = completed - started;
1214 if (cur_ops->started)
1215 completed++;
1216 if (completed > RCU_TORTURE_PIPE_LEN) {
1217 /* Should not happen, but... */
1218 completed = RCU_TORTURE_PIPE_LEN;
1219 }
1220 __this_cpu_inc(rcu_torture_batch[completed]);
1221 preempt_enable();
1222 cur_ops->readunlock(idx);
1223 stutter_wait("rcu_torture_reader");
1224 } while (!torture_must_stop());
1225 if (irqreader && cur_ops->irq_capable) {
1226 del_timer_sync(&t);
1227 destroy_timer_on_stack(&t);
1228 }
1229 torture_kthread_stopping("rcu_torture_reader");
1230 return 0;
1231}
1232
1233/*
1234 * Print torture statistics. Caller must ensure that there is only
1235 * one call to this function at a given time!!! This is normally
1236 * accomplished by relying on the module system to only have one copy
1237 * of the module loaded, and then by giving the rcu_torture_stats
1238 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1239 * thread is not running).
1240 */
1241static void
1242rcu_torture_stats_print(void)
1243{
1244 int cpu;
1245 int i;
1246 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1247 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1248 static unsigned long rtcv_snap = ULONG_MAX;
1249 static bool splatted;
1250 struct task_struct *wtp;
1251
1252 for_each_possible_cpu(cpu) {
1253 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1254 pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
1255 batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
1256 }
1257 }
1258 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
1259 if (pipesummary[i] != 0)
1260 break;
1261 }
1262
1263 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1264 pr_cont("rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
1265 rcu_torture_current,
1266 rcu_torture_current_version,
1267 list_empty(&rcu_torture_freelist),
1268 atomic_read(&n_rcu_torture_alloc),
1269 atomic_read(&n_rcu_torture_alloc_fail),
1270 atomic_read(&n_rcu_torture_free));
1271 pr_cont("rtmbe: %d rtbe: %ld rtbke: %ld rtbre: %ld ",
1272 atomic_read(&n_rcu_torture_mberror),
1273 n_rcu_torture_barrier_error,
1274 n_rcu_torture_boost_ktrerror,
1275 n_rcu_torture_boost_rterror);
1276 pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
1277 n_rcu_torture_boost_failure,
1278 n_rcu_torture_boosts,
1279 n_rcu_torture_timers);
1280 torture_onoff_stats();
1281 pr_cont("barrier: %ld/%ld:%ld ",
1282 n_barrier_successes,
1283 n_barrier_attempts,
1284 n_rcu_torture_barrier_error);
1285 pr_cont("cbflood: %ld\n", atomic_long_read(&n_cbfloods));
1286
1287 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1288 if (atomic_read(&n_rcu_torture_mberror) != 0 ||
1289 n_rcu_torture_barrier_error != 0 ||
1290 n_rcu_torture_boost_ktrerror != 0 ||
1291 n_rcu_torture_boost_rterror != 0 ||
1292 n_rcu_torture_boost_failure != 0 ||
1293 i > 1) {
1294 pr_cont("%s", "!!! ");
1295 atomic_inc(&n_rcu_torture_error);
1296 WARN_ON_ONCE(1);
1297 }
1298 pr_cont("Reader Pipe: ");
1299 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1300 pr_cont(" %ld", pipesummary[i]);
1301 pr_cont("\n");
1302
1303 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1304 pr_cont("Reader Batch: ");
1305 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1306 pr_cont(" %ld", batchsummary[i]);
1307 pr_cont("\n");
1308
1309 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1310 pr_cont("Free-Block Circulation: ");
1311 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1312 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
1313 }
1314 pr_cont("\n");
1315
1316 if (cur_ops->stats)
1317 cur_ops->stats();
1318 if (rtcv_snap == rcu_torture_current_version &&
1319 rcu_torture_current != NULL) {
1320 int __maybe_unused flags = 0;
1321 unsigned long __maybe_unused gpnum = 0;
1322 unsigned long __maybe_unused completed = 0;
1323
1324 rcutorture_get_gp_data(cur_ops->ttype,
1325 &flags, &gpnum, &completed);
1326 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp,
1327 &flags, &gpnum, &completed);
1328 wtp = READ_ONCE(writer_task);
1329 pr_alert("??? Writer stall state %s(%d) g%lu c%lu f%#x ->state %#lx cpu %d\n",
1330 rcu_torture_writer_state_getname(),
1331 rcu_torture_writer_state,
1332 gpnum, completed, flags,
1333 wtp == NULL ? ~0UL : wtp->state,
1334 wtp == NULL ? -1 : (int)task_cpu(wtp));
1335 if (!splatted && wtp) {
1336 sched_show_task(wtp);
1337 splatted = true;
1338 }
1339 show_rcu_gp_kthreads();
1340 rcu_ftrace_dump(DUMP_ALL);
1341 }
1342 rtcv_snap = rcu_torture_current_version;
1343}
1344
1345/*
1346 * Periodically prints torture statistics, if periodic statistics printing
1347 * was specified via the stat_interval module parameter.
1348 */
1349static int
1350rcu_torture_stats(void *arg)
1351{
1352 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1353 do {
1354 schedule_timeout_interruptible(stat_interval * HZ);
1355 rcu_torture_stats_print();
1356 torture_shutdown_absorb("rcu_torture_stats");
1357 } while (!torture_must_stop());
1358 torture_kthread_stopping("rcu_torture_stats");
1359 return 0;
1360}
1361
1362static inline void
1363rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1364{
1365 pr_alert("%s" TORTURE_FLAG
1366 "--- %s: nreaders=%d nfakewriters=%d "
1367 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1368 "shuffle_interval=%d stutter=%d irqreader=%d "
1369 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1370 "test_boost=%d/%d test_boost_interval=%d "
1371 "test_boost_duration=%d shutdown_secs=%d "
1372 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d "
1373 "n_barrier_cbs=%d "
1374 "onoff_interval=%d onoff_holdoff=%d\n",
1375 torture_type, tag, nrealreaders, nfakewriters,
1376 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1377 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1378 test_boost, cur_ops->can_boost,
1379 test_boost_interval, test_boost_duration, shutdown_secs,
1380 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff,
1381 n_barrier_cbs,
1382 onoff_interval, onoff_holdoff);
1383}
1384
1385static int rcutorture_booster_cleanup(unsigned int cpu)
1386{
1387 struct task_struct *t;
1388
1389 if (boost_tasks[cpu] == NULL)
1390 return 0;
1391 mutex_lock(&boost_mutex);
1392 t = boost_tasks[cpu];
1393 boost_tasks[cpu] = NULL;
1394 mutex_unlock(&boost_mutex);
1395
1396 /* This must be outside of the mutex, otherwise deadlock! */
1397 torture_stop_kthread(rcu_torture_boost, t);
1398 return 0;
1399}
1400
1401static int rcutorture_booster_init(unsigned int cpu)
1402{
1403 int retval;
1404
1405 if (boost_tasks[cpu] != NULL)
1406 return 0; /* Already created, nothing more to do. */
1407
1408 /* Don't allow time recalculation while creating a new task. */
1409 mutex_lock(&boost_mutex);
1410 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
1411 boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
1412 cpu_to_node(cpu),
1413 "rcu_torture_boost");
1414 if (IS_ERR(boost_tasks[cpu])) {
1415 retval = PTR_ERR(boost_tasks[cpu]);
1416 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
1417 n_rcu_torture_boost_ktrerror++;
1418 boost_tasks[cpu] = NULL;
1419 mutex_unlock(&boost_mutex);
1420 return retval;
1421 }
1422 kthread_bind(boost_tasks[cpu], cpu);
1423 wake_up_process(boost_tasks[cpu]);
1424 mutex_unlock(&boost_mutex);
1425 return 0;
1426}
1427
1428/*
1429 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
1430 * induces a CPU stall for the time specified by stall_cpu.
1431 */
1432static int rcu_torture_stall(void *args)
1433{
1434 unsigned long stop_at;
1435
1436 VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
1437 if (stall_cpu_holdoff > 0) {
1438 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
1439 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
1440 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
1441 }
1442 if (!kthread_should_stop()) {
1443 stop_at = get_seconds() + stall_cpu;
1444 /* RCU CPU stall is expected behavior in following code. */
1445 rcu_read_lock();
1446 if (stall_cpu_irqsoff)
1447 local_irq_disable();
1448 else
1449 preempt_disable();
1450 pr_alert("rcu_torture_stall start on CPU %d.\n",
1451 smp_processor_id());
1452 while (ULONG_CMP_LT(get_seconds(), stop_at))
1453 continue; /* Induce RCU CPU stall warning. */
1454 if (stall_cpu_irqsoff)
1455 local_irq_enable();
1456 else
1457 preempt_enable();
1458 rcu_read_unlock();
1459 pr_alert("rcu_torture_stall end.\n");
1460 }
1461 torture_shutdown_absorb("rcu_torture_stall");
1462 while (!kthread_should_stop())
1463 schedule_timeout_interruptible(10 * HZ);
1464 return 0;
1465}
1466
1467/* Spawn CPU-stall kthread, if stall_cpu specified. */
1468static int __init rcu_torture_stall_init(void)
1469{
1470 if (stall_cpu <= 0)
1471 return 0;
1472 return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
1473}
1474
1475/* Callback function for RCU barrier testing. */
1476static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
1477{
1478 atomic_inc(&barrier_cbs_invoked);
1479}
1480
1481/* kthread function to register callbacks used to test RCU barriers. */
1482static int rcu_torture_barrier_cbs(void *arg)
1483{
1484 long myid = (long)arg;
1485 bool lastphase = 0;
1486 bool newphase;
1487 struct rcu_head rcu;
1488
1489 init_rcu_head_on_stack(&rcu);
1490 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
1491 set_user_nice(current, MAX_NICE);
1492 do {
1493 wait_event(barrier_cbs_wq[myid],
1494 (newphase =
1495 smp_load_acquire(&barrier_phase)) != lastphase ||
1496 torture_must_stop());
1497 lastphase = newphase;
1498 if (torture_must_stop())
1499 break;
1500 /*
1501 * The above smp_load_acquire() ensures barrier_phase load
1502 * is ordered before the following ->call().
1503 */
1504 local_irq_disable(); /* Just to test no-irq call_rcu(). */
1505 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
1506 local_irq_enable();
1507 if (atomic_dec_and_test(&barrier_cbs_count))
1508 wake_up(&barrier_wq);
1509 } while (!torture_must_stop());
1510 if (cur_ops->cb_barrier != NULL)
1511 cur_ops->cb_barrier();
1512 destroy_rcu_head_on_stack(&rcu);
1513 torture_kthread_stopping("rcu_torture_barrier_cbs");
1514 return 0;
1515}
1516
1517/* kthread function to drive and coordinate RCU barrier testing. */
1518static int rcu_torture_barrier(void *arg)
1519{
1520 int i;
1521
1522 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
1523 do {
1524 atomic_set(&barrier_cbs_invoked, 0);
1525 atomic_set(&barrier_cbs_count, n_barrier_cbs);
1526 /* Ensure barrier_phase ordered after prior assignments. */
1527 smp_store_release(&barrier_phase, !barrier_phase);
1528 for (i = 0; i < n_barrier_cbs; i++)
1529 wake_up(&barrier_cbs_wq[i]);
1530 wait_event(barrier_wq,
1531 atomic_read(&barrier_cbs_count) == 0 ||
1532 torture_must_stop());
1533 if (torture_must_stop())
1534 break;
1535 n_barrier_attempts++;
1536 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
1537 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
1538 n_rcu_torture_barrier_error++;
1539 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
1540 atomic_read(&barrier_cbs_invoked),
1541 n_barrier_cbs);
1542 WARN_ON_ONCE(1);
1543 }
1544 n_barrier_successes++;
1545 schedule_timeout_interruptible(HZ / 10);
1546 } while (!torture_must_stop());
1547 torture_kthread_stopping("rcu_torture_barrier");
1548 return 0;
1549}
1550
1551/* Initialize RCU barrier testing. */
1552static int rcu_torture_barrier_init(void)
1553{
1554 int i;
1555 int ret;
1556
1557 if (n_barrier_cbs <= 0)
1558 return 0;
1559 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
1560 pr_alert("%s" TORTURE_FLAG
1561 " Call or barrier ops missing for %s,\n",
1562 torture_type, cur_ops->name);
1563 pr_alert("%s" TORTURE_FLAG
1564 " RCU barrier testing omitted from run.\n",
1565 torture_type);
1566 return 0;
1567 }
1568 atomic_set(&barrier_cbs_count, 0);
1569 atomic_set(&barrier_cbs_invoked, 0);
1570 barrier_cbs_tasks =
1571 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]),
1572 GFP_KERNEL);
1573 barrier_cbs_wq =
1574 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL);
1575 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
1576 return -ENOMEM;
1577 for (i = 0; i < n_barrier_cbs; i++) {
1578 init_waitqueue_head(&barrier_cbs_wq[i]);
1579 ret = torture_create_kthread(rcu_torture_barrier_cbs,
1580 (void *)(long)i,
1581 barrier_cbs_tasks[i]);
1582 if (ret)
1583 return ret;
1584 }
1585 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
1586}
1587
1588/* Clean up after RCU barrier testing. */
1589static void rcu_torture_barrier_cleanup(void)
1590{
1591 int i;
1592
1593 torture_stop_kthread(rcu_torture_barrier, barrier_task);
1594 if (barrier_cbs_tasks != NULL) {
1595 for (i = 0; i < n_barrier_cbs; i++)
1596 torture_stop_kthread(rcu_torture_barrier_cbs,
1597 barrier_cbs_tasks[i]);
1598 kfree(barrier_cbs_tasks);
1599 barrier_cbs_tasks = NULL;
1600 }
1601 if (barrier_cbs_wq != NULL) {
1602 kfree(barrier_cbs_wq);
1603 barrier_cbs_wq = NULL;
1604 }
1605}
1606
1607static enum cpuhp_state rcutor_hp;
1608
1609static void
1610rcu_torture_cleanup(void)
1611{
1612 int i;
1613
1614 rcutorture_record_test_transition();
1615 if (torture_cleanup_begin()) {
1616 if (cur_ops->cb_barrier != NULL)
1617 cur_ops->cb_barrier();
1618 return;
1619 }
1620
1621 rcu_torture_barrier_cleanup();
1622 torture_stop_kthread(rcu_torture_stall, stall_task);
1623 torture_stop_kthread(rcu_torture_writer, writer_task);
1624
1625 if (reader_tasks) {
1626 for (i = 0; i < nrealreaders; i++)
1627 torture_stop_kthread(rcu_torture_reader,
1628 reader_tasks[i]);
1629 kfree(reader_tasks);
1630 }
1631 rcu_torture_current = NULL;
1632
1633 if (fakewriter_tasks) {
1634 for (i = 0; i < nfakewriters; i++) {
1635 torture_stop_kthread(rcu_torture_fakewriter,
1636 fakewriter_tasks[i]);
1637 }
1638 kfree(fakewriter_tasks);
1639 fakewriter_tasks = NULL;
1640 }
1641
1642 torture_stop_kthread(rcu_torture_stats, stats_task);
1643 torture_stop_kthread(rcu_torture_fqs, fqs_task);
1644 for (i = 0; i < ncbflooders; i++)
1645 torture_stop_kthread(rcu_torture_cbflood, cbflood_task[i]);
1646 if ((test_boost == 1 && cur_ops->can_boost) ||
1647 test_boost == 2)
1648 cpuhp_remove_state(rcutor_hp);
1649
1650 /*
1651 * Wait for all RCU callbacks to fire, then do flavor-specific
1652 * cleanup operations.
1653 */
1654 if (cur_ops->cb_barrier != NULL)
1655 cur_ops->cb_barrier();
1656 if (cur_ops->cleanup != NULL)
1657 cur_ops->cleanup();
1658
1659 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
1660
1661 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
1662 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
1663 else if (torture_onoff_failures())
1664 rcu_torture_print_module_parms(cur_ops,
1665 "End of test: RCU_HOTPLUG");
1666 else
1667 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
1668 torture_cleanup_end();
1669}
1670
1671#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1672static void rcu_torture_leak_cb(struct rcu_head *rhp)
1673{
1674}
1675
1676static void rcu_torture_err_cb(struct rcu_head *rhp)
1677{
1678 /*
1679 * This -might- happen due to race conditions, but is unlikely.
1680 * The scenario that leads to this happening is that the
1681 * first of the pair of duplicate callbacks is queued,
1682 * someone else starts a grace period that includes that
1683 * callback, then the second of the pair must wait for the
1684 * next grace period. Unlikely, but can happen. If it
1685 * does happen, the debug-objects subsystem won't have splatted.
1686 */
1687 pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME);
1688}
1689#endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1690
1691/*
1692 * Verify that double-free causes debug-objects to complain, but only
1693 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
1694 * cannot be carried out.
1695 */
1696static void rcu_test_debug_objects(void)
1697{
1698#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1699 struct rcu_head rh1;
1700 struct rcu_head rh2;
1701
1702 init_rcu_head_on_stack(&rh1);
1703 init_rcu_head_on_stack(&rh2);
1704 pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME);
1705
1706 /* Try to queue the rh2 pair of callbacks for the same grace period. */
1707 preempt_disable(); /* Prevent preemption from interrupting test. */
1708 rcu_read_lock(); /* Make it impossible to finish a grace period. */
1709 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
1710 local_irq_disable(); /* Make it harder to start a new grace period. */
1711 call_rcu(&rh2, rcu_torture_leak_cb);
1712 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
1713 local_irq_enable();
1714 rcu_read_unlock();
1715 preempt_enable();
1716
1717 /* Wait for them all to get done so we can safely return. */
1718 rcu_barrier();
1719 pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME);
1720 destroy_rcu_head_on_stack(&rh1);
1721 destroy_rcu_head_on_stack(&rh2);
1722#else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1723 pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME);
1724#endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1725}
1726
1727static int __init
1728rcu_torture_init(void)
1729{
1730 int i;
1731 int cpu;
1732 int firsterr = 0;
1733 static struct rcu_torture_ops *torture_ops[] = {
1734 &rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops,
1735 &sched_ops, &tasks_ops,
1736 };
1737
1738 if (!torture_init_begin(torture_type, verbose))
1739 return -EBUSY;
1740
1741 /* Process args and tell the world that the torturer is on the job. */
1742 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1743 cur_ops = torture_ops[i];
1744 if (strcmp(torture_type, cur_ops->name) == 0)
1745 break;
1746 }
1747 if (i == ARRAY_SIZE(torture_ops)) {
1748 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
1749 torture_type);
1750 pr_alert("rcu-torture types:");
1751 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1752 pr_alert(" %s", torture_ops[i]->name);
1753 pr_alert("\n");
1754 firsterr = -EINVAL;
1755 goto unwind;
1756 }
1757 if (cur_ops->fqs == NULL && fqs_duration != 0) {
1758 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
1759 fqs_duration = 0;
1760 }
1761 if (cur_ops->init)
1762 cur_ops->init();
1763
1764 if (nreaders >= 0) {
1765 nrealreaders = nreaders;
1766 } else {
1767 nrealreaders = num_online_cpus() - 2 - nreaders;
1768 if (nrealreaders <= 0)
1769 nrealreaders = 1;
1770 }
1771 rcu_torture_print_module_parms(cur_ops, "Start of test");
1772
1773 /* Set up the freelist. */
1774
1775 INIT_LIST_HEAD(&rcu_torture_freelist);
1776 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1777 rcu_tortures[i].rtort_mbtest = 0;
1778 list_add_tail(&rcu_tortures[i].rtort_free,
1779 &rcu_torture_freelist);
1780 }
1781
1782 /* Initialize the statistics so that each run gets its own numbers. */
1783
1784 rcu_torture_current = NULL;
1785 rcu_torture_current_version = 0;
1786 atomic_set(&n_rcu_torture_alloc, 0);
1787 atomic_set(&n_rcu_torture_alloc_fail, 0);
1788 atomic_set(&n_rcu_torture_free, 0);
1789 atomic_set(&n_rcu_torture_mberror, 0);
1790 atomic_set(&n_rcu_torture_error, 0);
1791 n_rcu_torture_barrier_error = 0;
1792 n_rcu_torture_boost_ktrerror = 0;
1793 n_rcu_torture_boost_rterror = 0;
1794 n_rcu_torture_boost_failure = 0;
1795 n_rcu_torture_boosts = 0;
1796 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1797 atomic_set(&rcu_torture_wcount[i], 0);
1798 for_each_possible_cpu(cpu) {
1799 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1800 per_cpu(rcu_torture_count, cpu)[i] = 0;
1801 per_cpu(rcu_torture_batch, cpu)[i] = 0;
1802 }
1803 }
1804
1805 /* Start up the kthreads. */
1806
1807 firsterr = torture_create_kthread(rcu_torture_writer, NULL,
1808 writer_task);
1809 if (firsterr)
1810 goto unwind;
1811 if (nfakewriters > 0) {
1812 fakewriter_tasks = kcalloc(nfakewriters,
1813 sizeof(fakewriter_tasks[0]),
1814 GFP_KERNEL);
1815 if (fakewriter_tasks == NULL) {
1816 VERBOSE_TOROUT_ERRSTRING("out of memory");
1817 firsterr = -ENOMEM;
1818 goto unwind;
1819 }
1820 }
1821 for (i = 0; i < nfakewriters; i++) {
1822 firsterr = torture_create_kthread(rcu_torture_fakewriter,
1823 NULL, fakewriter_tasks[i]);
1824 if (firsterr)
1825 goto unwind;
1826 }
1827 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
1828 GFP_KERNEL);
1829 if (reader_tasks == NULL) {
1830 VERBOSE_TOROUT_ERRSTRING("out of memory");
1831 firsterr = -ENOMEM;
1832 goto unwind;
1833 }
1834 for (i = 0; i < nrealreaders; i++) {
1835 firsterr = torture_create_kthread(rcu_torture_reader, NULL,
1836 reader_tasks[i]);
1837 if (firsterr)
1838 goto unwind;
1839 }
1840 if (stat_interval > 0) {
1841 firsterr = torture_create_kthread(rcu_torture_stats, NULL,
1842 stats_task);
1843 if (firsterr)
1844 goto unwind;
1845 }
1846 if (test_no_idle_hz && shuffle_interval > 0) {
1847 firsterr = torture_shuffle_init(shuffle_interval * HZ);
1848 if (firsterr)
1849 goto unwind;
1850 }
1851 if (stutter < 0)
1852 stutter = 0;
1853 if (stutter) {
1854 firsterr = torture_stutter_init(stutter * HZ);
1855 if (firsterr)
1856 goto unwind;
1857 }
1858 if (fqs_duration < 0)
1859 fqs_duration = 0;
1860 if (fqs_duration) {
1861 /* Create the fqs thread */
1862 firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
1863 fqs_task);
1864 if (firsterr)
1865 goto unwind;
1866 }
1867 if (test_boost_interval < 1)
1868 test_boost_interval = 1;
1869 if (test_boost_duration < 2)
1870 test_boost_duration = 2;
1871 if ((test_boost == 1 && cur_ops->can_boost) ||
1872 test_boost == 2) {
1873
1874 boost_starttime = jiffies + test_boost_interval * HZ;
1875
1876 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE",
1877 rcutorture_booster_init,
1878 rcutorture_booster_cleanup);
1879 if (firsterr < 0)
1880 goto unwind;
1881 rcutor_hp = firsterr;
1882 }
1883 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
1884 if (firsterr)
1885 goto unwind;
1886 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval * HZ);
1887 if (firsterr)
1888 goto unwind;
1889 firsterr = rcu_torture_stall_init();
1890 if (firsterr)
1891 goto unwind;
1892 firsterr = rcu_torture_barrier_init();
1893 if (firsterr)
1894 goto unwind;
1895 if (object_debug)
1896 rcu_test_debug_objects();
1897 if (cbflood_n_burst > 0) {
1898 /* Create the cbflood threads */
1899 ncbflooders = (num_online_cpus() + 3) / 4;
1900 cbflood_task = kcalloc(ncbflooders, sizeof(*cbflood_task),
1901 GFP_KERNEL);
1902 if (!cbflood_task) {
1903 VERBOSE_TOROUT_ERRSTRING("out of memory");
1904 firsterr = -ENOMEM;
1905 goto unwind;
1906 }
1907 for (i = 0; i < ncbflooders; i++) {
1908 firsterr = torture_create_kthread(rcu_torture_cbflood,
1909 NULL,
1910 cbflood_task[i]);
1911 if (firsterr)
1912 goto unwind;
1913 }
1914 }
1915 rcutorture_record_test_transition();
1916 torture_init_end();
1917 return 0;
1918
1919unwind:
1920 torture_init_end();
1921 rcu_torture_cleanup();
1922 return firsterr;
1923}
1924
1925module_init(rcu_torture_init);
1926module_exit(rcu_torture_cleanup);