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1/*
2 * Read-Copy Update module-based torture test facility
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, you can access it online at
16 * http://www.gnu.org/licenses/gpl-2.0.html.
17 *
18 * Copyright (C) IBM Corporation, 2005, 2006
19 *
20 * Authors: Paul E. McKenney <paulmck@us.ibm.com>
21 * Josh Triplett <josh@freedesktop.org>
22 *
23 * See also: Documentation/RCU/torture.txt
24 */
25#include <linux/types.h>
26#include <linux/kernel.h>
27#include <linux/init.h>
28#include <linux/module.h>
29#include <linux/kthread.h>
30#include <linux/err.h>
31#include <linux/spinlock.h>
32#include <linux/smp.h>
33#include <linux/rcupdate.h>
34#include <linux/interrupt.h>
35#include <linux/sched.h>
36#include <linux/atomic.h>
37#include <linux/bitops.h>
38#include <linux/completion.h>
39#include <linux/moduleparam.h>
40#include <linux/percpu.h>
41#include <linux/notifier.h>
42#include <linux/reboot.h>
43#include <linux/freezer.h>
44#include <linux/cpu.h>
45#include <linux/delay.h>
46#include <linux/stat.h>
47#include <linux/srcu.h>
48#include <linux/slab.h>
49#include <linux/trace_clock.h>
50#include <asm/byteorder.h>
51#include <linux/torture.h>
52
53MODULE_LICENSE("GPL");
54MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@freedesktop.org>");
55
56
57torture_param(int, fqs_duration, 0,
58 "Duration of fqs bursts (us), 0 to disable");
59torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
60torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
61torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
62torture_param(bool, gp_normal, false,
63 "Use normal (non-expedited) GP wait primitives");
64torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
65torture_param(int, n_barrier_cbs, 0,
66 "# of callbacks/kthreads for barrier testing");
67torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
68torture_param(int, nreaders, -1, "Number of RCU reader threads");
69torture_param(int, object_debug, 0,
70 "Enable debug-object double call_rcu() testing");
71torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
72torture_param(int, onoff_interval, 0,
73 "Time between CPU hotplugs (s), 0=disable");
74torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
75torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
76torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
77torture_param(int, stall_cpu_holdoff, 10,
78 "Time to wait before starting stall (s).");
79torture_param(int, stat_interval, 60,
80 "Number of seconds between stats printk()s");
81torture_param(int, stutter, 5, "Number of seconds to run/halt test");
82torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
83torture_param(int, test_boost_duration, 4,
84 "Duration of each boost test, seconds.");
85torture_param(int, test_boost_interval, 7,
86 "Interval between boost tests, seconds.");
87torture_param(bool, test_no_idle_hz, true,
88 "Test support for tickless idle CPUs");
89torture_param(bool, verbose, true,
90 "Enable verbose debugging printk()s");
91
92static char *torture_type = "rcu";
93module_param(torture_type, charp, 0444);
94MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, ...)");
95
96static int nrealreaders;
97static struct task_struct *writer_task;
98static struct task_struct **fakewriter_tasks;
99static struct task_struct **reader_tasks;
100static struct task_struct *stats_task;
101static struct task_struct *fqs_task;
102static struct task_struct *boost_tasks[NR_CPUS];
103static struct task_struct *stall_task;
104static struct task_struct **barrier_cbs_tasks;
105static struct task_struct *barrier_task;
106
107#define RCU_TORTURE_PIPE_LEN 10
108
109struct rcu_torture {
110 struct rcu_head rtort_rcu;
111 int rtort_pipe_count;
112 struct list_head rtort_free;
113 int rtort_mbtest;
114};
115
116static LIST_HEAD(rcu_torture_freelist);
117static struct rcu_torture __rcu *rcu_torture_current;
118static unsigned long rcu_torture_current_version;
119static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
120static DEFINE_SPINLOCK(rcu_torture_lock);
121static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1],
122 rcu_torture_count) = { 0 };
123static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1],
124 rcu_torture_batch) = { 0 };
125static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
126static atomic_t n_rcu_torture_alloc;
127static atomic_t n_rcu_torture_alloc_fail;
128static atomic_t n_rcu_torture_free;
129static atomic_t n_rcu_torture_mberror;
130static atomic_t n_rcu_torture_error;
131static long n_rcu_torture_barrier_error;
132static long n_rcu_torture_boost_ktrerror;
133static long n_rcu_torture_boost_rterror;
134static long n_rcu_torture_boost_failure;
135static long n_rcu_torture_boosts;
136static long n_rcu_torture_timers;
137static long n_barrier_attempts;
138static long n_barrier_successes;
139static struct list_head rcu_torture_removed;
140
141#if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
142#define RCUTORTURE_RUNNABLE_INIT 1
143#else
144#define RCUTORTURE_RUNNABLE_INIT 0
145#endif
146int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT;
147module_param(rcutorture_runnable, int, 0444);
148MODULE_PARM_DESC(rcutorture_runnable, "Start rcutorture at boot");
149
150#if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
151#define rcu_can_boost() 1
152#else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
153#define rcu_can_boost() 0
154#endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
155
156#ifdef CONFIG_RCU_TRACE
157static u64 notrace rcu_trace_clock_local(void)
158{
159 u64 ts = trace_clock_local();
160 unsigned long __maybe_unused ts_rem = do_div(ts, NSEC_PER_USEC);
161 return ts;
162}
163#else /* #ifdef CONFIG_RCU_TRACE */
164static u64 notrace rcu_trace_clock_local(void)
165{
166 return 0ULL;
167}
168#endif /* #else #ifdef CONFIG_RCU_TRACE */
169
170static unsigned long boost_starttime; /* jiffies of next boost test start. */
171DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
172 /* and boost task create/destroy. */
173static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
174static bool barrier_phase; /* Test phase. */
175static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
176static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
177static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
178
179/*
180 * Allocate an element from the rcu_tortures pool.
181 */
182static struct rcu_torture *
183rcu_torture_alloc(void)
184{
185 struct list_head *p;
186
187 spin_lock_bh(&rcu_torture_lock);
188 if (list_empty(&rcu_torture_freelist)) {
189 atomic_inc(&n_rcu_torture_alloc_fail);
190 spin_unlock_bh(&rcu_torture_lock);
191 return NULL;
192 }
193 atomic_inc(&n_rcu_torture_alloc);
194 p = rcu_torture_freelist.next;
195 list_del_init(p);
196 spin_unlock_bh(&rcu_torture_lock);
197 return container_of(p, struct rcu_torture, rtort_free);
198}
199
200/*
201 * Free an element to the rcu_tortures pool.
202 */
203static void
204rcu_torture_free(struct rcu_torture *p)
205{
206 atomic_inc(&n_rcu_torture_free);
207 spin_lock_bh(&rcu_torture_lock);
208 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
209 spin_unlock_bh(&rcu_torture_lock);
210}
211
212/*
213 * Operations vector for selecting different types of tests.
214 */
215
216struct rcu_torture_ops {
217 void (*init)(void);
218 int (*readlock)(void);
219 void (*read_delay)(struct torture_random_state *rrsp);
220 void (*readunlock)(int idx);
221 int (*completed)(void);
222 void (*deferred_free)(struct rcu_torture *p);
223 void (*sync)(void);
224 void (*exp_sync)(void);
225 void (*call)(struct rcu_head *head, void (*func)(struct rcu_head *rcu));
226 void (*cb_barrier)(void);
227 void (*fqs)(void);
228 void (*stats)(char *page);
229 int irq_capable;
230 int can_boost;
231 const char *name;
232};
233
234static struct rcu_torture_ops *cur_ops;
235
236/*
237 * Definitions for rcu torture testing.
238 */
239
240static int rcu_torture_read_lock(void) __acquires(RCU)
241{
242 rcu_read_lock();
243 return 0;
244}
245
246static void rcu_read_delay(struct torture_random_state *rrsp)
247{
248 const unsigned long shortdelay_us = 200;
249 const unsigned long longdelay_ms = 50;
250
251 /* We want a short delay sometimes to make a reader delay the grace
252 * period, and we want a long delay occasionally to trigger
253 * force_quiescent_state. */
254
255 if (!(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms)))
256 mdelay(longdelay_ms);
257 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
258 udelay(shortdelay_us);
259#ifdef CONFIG_PREEMPT
260 if (!preempt_count() &&
261 !(torture_random(rrsp) % (nrealreaders * 20000)))
262 preempt_schedule(); /* No QS if preempt_disable() in effect */
263#endif
264}
265
266static void rcu_torture_read_unlock(int idx) __releases(RCU)
267{
268 rcu_read_unlock();
269}
270
271static int rcu_torture_completed(void)
272{
273 return rcu_batches_completed();
274}
275
276static void
277rcu_torture_cb(struct rcu_head *p)
278{
279 int i;
280 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
281
282 if (torture_must_stop_irq()) {
283 /* Test is ending, just drop callbacks on the floor. */
284 /* The next initialization will pick up the pieces. */
285 return;
286 }
287 i = rp->rtort_pipe_count;
288 if (i > RCU_TORTURE_PIPE_LEN)
289 i = RCU_TORTURE_PIPE_LEN;
290 atomic_inc(&rcu_torture_wcount[i]);
291 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
292 rp->rtort_mbtest = 0;
293 rcu_torture_free(rp);
294 } else {
295 cur_ops->deferred_free(rp);
296 }
297}
298
299static int rcu_no_completed(void)
300{
301 return 0;
302}
303
304static void rcu_torture_deferred_free(struct rcu_torture *p)
305{
306 call_rcu(&p->rtort_rcu, rcu_torture_cb);
307}
308
309static void rcu_sync_torture_init(void)
310{
311 INIT_LIST_HEAD(&rcu_torture_removed);
312}
313
314static struct rcu_torture_ops rcu_ops = {
315 .init = rcu_sync_torture_init,
316 .readlock = rcu_torture_read_lock,
317 .read_delay = rcu_read_delay,
318 .readunlock = rcu_torture_read_unlock,
319 .completed = rcu_torture_completed,
320 .deferred_free = rcu_torture_deferred_free,
321 .sync = synchronize_rcu,
322 .exp_sync = synchronize_rcu_expedited,
323 .call = call_rcu,
324 .cb_barrier = rcu_barrier,
325 .fqs = rcu_force_quiescent_state,
326 .stats = NULL,
327 .irq_capable = 1,
328 .can_boost = rcu_can_boost(),
329 .name = "rcu"
330};
331
332/*
333 * Definitions for rcu_bh torture testing.
334 */
335
336static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
337{
338 rcu_read_lock_bh();
339 return 0;
340}
341
342static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
343{
344 rcu_read_unlock_bh();
345}
346
347static int rcu_bh_torture_completed(void)
348{
349 return rcu_batches_completed_bh();
350}
351
352static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
353{
354 call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
355}
356
357static struct rcu_torture_ops rcu_bh_ops = {
358 .init = rcu_sync_torture_init,
359 .readlock = rcu_bh_torture_read_lock,
360 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
361 .readunlock = rcu_bh_torture_read_unlock,
362 .completed = rcu_bh_torture_completed,
363 .deferred_free = rcu_bh_torture_deferred_free,
364 .sync = synchronize_rcu_bh,
365 .exp_sync = synchronize_rcu_bh_expedited,
366 .call = call_rcu_bh,
367 .cb_barrier = rcu_barrier_bh,
368 .fqs = rcu_bh_force_quiescent_state,
369 .stats = NULL,
370 .irq_capable = 1,
371 .name = "rcu_bh"
372};
373
374/*
375 * Don't even think about trying any of these in real life!!!
376 * The names includes "busted", and they really means it!
377 * The only purpose of these functions is to provide a buggy RCU
378 * implementation to make sure that rcutorture correctly emits
379 * buggy-RCU error messages.
380 */
381static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
382{
383 /* This is a deliberate bug for testing purposes only! */
384 rcu_torture_cb(&p->rtort_rcu);
385}
386
387static void synchronize_rcu_busted(void)
388{
389 /* This is a deliberate bug for testing purposes only! */
390}
391
392static void
393call_rcu_busted(struct rcu_head *head, void (*func)(struct rcu_head *rcu))
394{
395 /* This is a deliberate bug for testing purposes only! */
396 func(head);
397}
398
399static struct rcu_torture_ops rcu_busted_ops = {
400 .init = rcu_sync_torture_init,
401 .readlock = rcu_torture_read_lock,
402 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
403 .readunlock = rcu_torture_read_unlock,
404 .completed = rcu_no_completed,
405 .deferred_free = rcu_busted_torture_deferred_free,
406 .sync = synchronize_rcu_busted,
407 .exp_sync = synchronize_rcu_busted,
408 .call = call_rcu_busted,
409 .cb_barrier = NULL,
410 .fqs = NULL,
411 .stats = NULL,
412 .irq_capable = 1,
413 .name = "rcu_busted"
414};
415
416/*
417 * Definitions for srcu torture testing.
418 */
419
420DEFINE_STATIC_SRCU(srcu_ctl);
421
422static int srcu_torture_read_lock(void) __acquires(&srcu_ctl)
423{
424 return srcu_read_lock(&srcu_ctl);
425}
426
427static void srcu_read_delay(struct torture_random_state *rrsp)
428{
429 long delay;
430 const long uspertick = 1000000 / HZ;
431 const long longdelay = 10;
432
433 /* We want there to be long-running readers, but not all the time. */
434
435 delay = torture_random(rrsp) %
436 (nrealreaders * 2 * longdelay * uspertick);
437 if (!delay)
438 schedule_timeout_interruptible(longdelay);
439 else
440 rcu_read_delay(rrsp);
441}
442
443static void srcu_torture_read_unlock(int idx) __releases(&srcu_ctl)
444{
445 srcu_read_unlock(&srcu_ctl, idx);
446}
447
448static int srcu_torture_completed(void)
449{
450 return srcu_batches_completed(&srcu_ctl);
451}
452
453static void srcu_torture_deferred_free(struct rcu_torture *rp)
454{
455 call_srcu(&srcu_ctl, &rp->rtort_rcu, rcu_torture_cb);
456}
457
458static void srcu_torture_synchronize(void)
459{
460 synchronize_srcu(&srcu_ctl);
461}
462
463static void srcu_torture_call(struct rcu_head *head,
464 void (*func)(struct rcu_head *head))
465{
466 call_srcu(&srcu_ctl, head, func);
467}
468
469static void srcu_torture_barrier(void)
470{
471 srcu_barrier(&srcu_ctl);
472}
473
474static void srcu_torture_stats(char *page)
475{
476 int cpu;
477 int idx = srcu_ctl.completed & 0x1;
478
479 page += sprintf(page, "%s%s per-CPU(idx=%d):",
480 torture_type, TORTURE_FLAG, idx);
481 for_each_possible_cpu(cpu) {
482 page += sprintf(page, " %d(%lu,%lu)", cpu,
483 per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx],
484 per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx]);
485 }
486 sprintf(page, "\n");
487}
488
489static void srcu_torture_synchronize_expedited(void)
490{
491 synchronize_srcu_expedited(&srcu_ctl);
492}
493
494static struct rcu_torture_ops srcu_ops = {
495 .init = rcu_sync_torture_init,
496 .readlock = srcu_torture_read_lock,
497 .read_delay = srcu_read_delay,
498 .readunlock = srcu_torture_read_unlock,
499 .completed = srcu_torture_completed,
500 .deferred_free = srcu_torture_deferred_free,
501 .sync = srcu_torture_synchronize,
502 .exp_sync = srcu_torture_synchronize_expedited,
503 .call = srcu_torture_call,
504 .cb_barrier = srcu_torture_barrier,
505 .stats = srcu_torture_stats,
506 .name = "srcu"
507};
508
509/*
510 * Definitions for sched torture testing.
511 */
512
513static int sched_torture_read_lock(void)
514{
515 preempt_disable();
516 return 0;
517}
518
519static void sched_torture_read_unlock(int idx)
520{
521 preempt_enable();
522}
523
524static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
525{
526 call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
527}
528
529static struct rcu_torture_ops sched_ops = {
530 .init = rcu_sync_torture_init,
531 .readlock = sched_torture_read_lock,
532 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
533 .readunlock = sched_torture_read_unlock,
534 .completed = rcu_no_completed,
535 .deferred_free = rcu_sched_torture_deferred_free,
536 .sync = synchronize_sched,
537 .exp_sync = synchronize_sched_expedited,
538 .call = call_rcu_sched,
539 .cb_barrier = rcu_barrier_sched,
540 .fqs = rcu_sched_force_quiescent_state,
541 .stats = NULL,
542 .irq_capable = 1,
543 .name = "sched"
544};
545
546/*
547 * RCU torture priority-boost testing. Runs one real-time thread per
548 * CPU for moderate bursts, repeatedly registering RCU callbacks and
549 * spinning waiting for them to be invoked. If a given callback takes
550 * too long to be invoked, we assume that priority inversion has occurred.
551 */
552
553struct rcu_boost_inflight {
554 struct rcu_head rcu;
555 int inflight;
556};
557
558static void rcu_torture_boost_cb(struct rcu_head *head)
559{
560 struct rcu_boost_inflight *rbip =
561 container_of(head, struct rcu_boost_inflight, rcu);
562
563 smp_mb(); /* Ensure RCU-core accesses precede clearing ->inflight */
564 rbip->inflight = 0;
565}
566
567static int rcu_torture_boost(void *arg)
568{
569 unsigned long call_rcu_time;
570 unsigned long endtime;
571 unsigned long oldstarttime;
572 struct rcu_boost_inflight rbi = { .inflight = 0 };
573 struct sched_param sp;
574
575 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
576
577 /* Set real-time priority. */
578 sp.sched_priority = 1;
579 if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
580 VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!");
581 n_rcu_torture_boost_rterror++;
582 }
583
584 init_rcu_head_on_stack(&rbi.rcu);
585 /* Each pass through the following loop does one boost-test cycle. */
586 do {
587 /* Wait for the next test interval. */
588 oldstarttime = boost_starttime;
589 while (ULONG_CMP_LT(jiffies, oldstarttime)) {
590 schedule_timeout_interruptible(oldstarttime - jiffies);
591 stutter_wait("rcu_torture_boost");
592 if (torture_must_stop())
593 goto checkwait;
594 }
595
596 /* Do one boost-test interval. */
597 endtime = oldstarttime + test_boost_duration * HZ;
598 call_rcu_time = jiffies;
599 while (ULONG_CMP_LT(jiffies, endtime)) {
600 /* If we don't have a callback in flight, post one. */
601 if (!rbi.inflight) {
602 smp_mb(); /* RCU core before ->inflight = 1. */
603 rbi.inflight = 1;
604 call_rcu(&rbi.rcu, rcu_torture_boost_cb);
605 if (jiffies - call_rcu_time >
606 test_boost_duration * HZ - HZ / 2) {
607 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
608 n_rcu_torture_boost_failure++;
609 }
610 call_rcu_time = jiffies;
611 }
612 cond_resched();
613 stutter_wait("rcu_torture_boost");
614 if (torture_must_stop())
615 goto checkwait;
616 }
617
618 /*
619 * Set the start time of the next test interval.
620 * Yes, this is vulnerable to long delays, but such
621 * delays simply cause a false negative for the next
622 * interval. Besides, we are running at RT priority,
623 * so delays should be relatively rare.
624 */
625 while (oldstarttime == boost_starttime &&
626 !kthread_should_stop()) {
627 if (mutex_trylock(&boost_mutex)) {
628 boost_starttime = jiffies +
629 test_boost_interval * HZ;
630 n_rcu_torture_boosts++;
631 mutex_unlock(&boost_mutex);
632 break;
633 }
634 schedule_timeout_uninterruptible(1);
635 }
636
637 /* Go do the stutter. */
638checkwait: stutter_wait("rcu_torture_boost");
639 } while (!torture_must_stop());
640
641 /* Clean up and exit. */
642 while (!kthread_should_stop() || rbi.inflight) {
643 torture_shutdown_absorb("rcu_torture_boost");
644 schedule_timeout_uninterruptible(1);
645 }
646 smp_mb(); /* order accesses to ->inflight before stack-frame death. */
647 destroy_rcu_head_on_stack(&rbi.rcu);
648 torture_kthread_stopping("rcu_torture_boost");
649 return 0;
650}
651
652/*
653 * RCU torture force-quiescent-state kthread. Repeatedly induces
654 * bursts of calls to force_quiescent_state(), increasing the probability
655 * of occurrence of some important types of race conditions.
656 */
657static int
658rcu_torture_fqs(void *arg)
659{
660 unsigned long fqs_resume_time;
661 int fqs_burst_remaining;
662
663 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
664 do {
665 fqs_resume_time = jiffies + fqs_stutter * HZ;
666 while (ULONG_CMP_LT(jiffies, fqs_resume_time) &&
667 !kthread_should_stop()) {
668 schedule_timeout_interruptible(1);
669 }
670 fqs_burst_remaining = fqs_duration;
671 while (fqs_burst_remaining > 0 &&
672 !kthread_should_stop()) {
673 cur_ops->fqs();
674 udelay(fqs_holdoff);
675 fqs_burst_remaining -= fqs_holdoff;
676 }
677 stutter_wait("rcu_torture_fqs");
678 } while (!torture_must_stop());
679 torture_kthread_stopping("rcu_torture_fqs");
680 return 0;
681}
682
683/*
684 * RCU torture writer kthread. Repeatedly substitutes a new structure
685 * for that pointed to by rcu_torture_current, freeing the old structure
686 * after a series of grace periods (the "pipeline").
687 */
688static int
689rcu_torture_writer(void *arg)
690{
691 bool exp;
692 int i;
693 struct rcu_torture *rp;
694 struct rcu_torture *rp1;
695 struct rcu_torture *old_rp;
696 static DEFINE_TORTURE_RANDOM(rand);
697
698 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
699 set_user_nice(current, MAX_NICE);
700
701 do {
702 schedule_timeout_uninterruptible(1);
703 rp = rcu_torture_alloc();
704 if (rp == NULL)
705 continue;
706 rp->rtort_pipe_count = 0;
707 udelay(torture_random(&rand) & 0x3ff);
708 old_rp = rcu_dereference_check(rcu_torture_current,
709 current == writer_task);
710 rp->rtort_mbtest = 1;
711 rcu_assign_pointer(rcu_torture_current, rp);
712 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
713 if (old_rp) {
714 i = old_rp->rtort_pipe_count;
715 if (i > RCU_TORTURE_PIPE_LEN)
716 i = RCU_TORTURE_PIPE_LEN;
717 atomic_inc(&rcu_torture_wcount[i]);
718 old_rp->rtort_pipe_count++;
719 if (gp_normal == gp_exp)
720 exp = !!(torture_random(&rand) & 0x80);
721 else
722 exp = gp_exp;
723 if (!exp) {
724 cur_ops->deferred_free(old_rp);
725 } else {
726 cur_ops->exp_sync();
727 list_add(&old_rp->rtort_free,
728 &rcu_torture_removed);
729 list_for_each_entry_safe(rp, rp1,
730 &rcu_torture_removed,
731 rtort_free) {
732 i = rp->rtort_pipe_count;
733 if (i > RCU_TORTURE_PIPE_LEN)
734 i = RCU_TORTURE_PIPE_LEN;
735 atomic_inc(&rcu_torture_wcount[i]);
736 if (++rp->rtort_pipe_count >=
737 RCU_TORTURE_PIPE_LEN) {
738 rp->rtort_mbtest = 0;
739 list_del(&rp->rtort_free);
740 rcu_torture_free(rp);
741 }
742 }
743 }
744 }
745 rcutorture_record_progress(++rcu_torture_current_version);
746 stutter_wait("rcu_torture_writer");
747 } while (!torture_must_stop());
748 torture_kthread_stopping("rcu_torture_writer");
749 return 0;
750}
751
752/*
753 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
754 * delay between calls.
755 */
756static int
757rcu_torture_fakewriter(void *arg)
758{
759 DEFINE_TORTURE_RANDOM(rand);
760
761 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
762 set_user_nice(current, MAX_NICE);
763
764 do {
765 schedule_timeout_uninterruptible(1 + torture_random(&rand)%10);
766 udelay(torture_random(&rand) & 0x3ff);
767 if (cur_ops->cb_barrier != NULL &&
768 torture_random(&rand) % (nfakewriters * 8) == 0) {
769 cur_ops->cb_barrier();
770 } else if (gp_normal == gp_exp) {
771 if (torture_random(&rand) & 0x80)
772 cur_ops->sync();
773 else
774 cur_ops->exp_sync();
775 } else if (gp_normal) {
776 cur_ops->sync();
777 } else {
778 cur_ops->exp_sync();
779 }
780 stutter_wait("rcu_torture_fakewriter");
781 } while (!torture_must_stop());
782
783 torture_kthread_stopping("rcu_torture_fakewriter");
784 return 0;
785}
786
787void rcutorture_trace_dump(void)
788{
789 static atomic_t beenhere = ATOMIC_INIT(0);
790
791 if (atomic_read(&beenhere))
792 return;
793 if (atomic_xchg(&beenhere, 1) != 0)
794 return;
795 ftrace_dump(DUMP_ALL);
796}
797
798/*
799 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
800 * incrementing the corresponding element of the pipeline array. The
801 * counter in the element should never be greater than 1, otherwise, the
802 * RCU implementation is broken.
803 */
804static void rcu_torture_timer(unsigned long unused)
805{
806 int idx;
807 int completed;
808 int completed_end;
809 static DEFINE_TORTURE_RANDOM(rand);
810 static DEFINE_SPINLOCK(rand_lock);
811 struct rcu_torture *p;
812 int pipe_count;
813 unsigned long long ts;
814
815 idx = cur_ops->readlock();
816 completed = cur_ops->completed();
817 ts = rcu_trace_clock_local();
818 p = rcu_dereference_check(rcu_torture_current,
819 rcu_read_lock_bh_held() ||
820 rcu_read_lock_sched_held() ||
821 srcu_read_lock_held(&srcu_ctl));
822 if (p == NULL) {
823 /* Leave because rcu_torture_writer is not yet underway */
824 cur_ops->readunlock(idx);
825 return;
826 }
827 if (p->rtort_mbtest == 0)
828 atomic_inc(&n_rcu_torture_mberror);
829 spin_lock(&rand_lock);
830 cur_ops->read_delay(&rand);
831 n_rcu_torture_timers++;
832 spin_unlock(&rand_lock);
833 preempt_disable();
834 pipe_count = p->rtort_pipe_count;
835 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
836 /* Should not happen, but... */
837 pipe_count = RCU_TORTURE_PIPE_LEN;
838 }
839 completed_end = cur_ops->completed();
840 if (pipe_count > 1) {
841 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, ts,
842 completed, completed_end);
843 rcutorture_trace_dump();
844 }
845 __this_cpu_inc(rcu_torture_count[pipe_count]);
846 completed = completed_end - completed;
847 if (completed > RCU_TORTURE_PIPE_LEN) {
848 /* Should not happen, but... */
849 completed = RCU_TORTURE_PIPE_LEN;
850 }
851 __this_cpu_inc(rcu_torture_batch[completed]);
852 preempt_enable();
853 cur_ops->readunlock(idx);
854}
855
856/*
857 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
858 * incrementing the corresponding element of the pipeline array. The
859 * counter in the element should never be greater than 1, otherwise, the
860 * RCU implementation is broken.
861 */
862static int
863rcu_torture_reader(void *arg)
864{
865 int completed;
866 int completed_end;
867 int idx;
868 DEFINE_TORTURE_RANDOM(rand);
869 struct rcu_torture *p;
870 int pipe_count;
871 struct timer_list t;
872 unsigned long long ts;
873
874 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
875 set_user_nice(current, MAX_NICE);
876 if (irqreader && cur_ops->irq_capable)
877 setup_timer_on_stack(&t, rcu_torture_timer, 0);
878
879 do {
880 if (irqreader && cur_ops->irq_capable) {
881 if (!timer_pending(&t))
882 mod_timer(&t, jiffies + 1);
883 }
884 idx = cur_ops->readlock();
885 completed = cur_ops->completed();
886 ts = rcu_trace_clock_local();
887 p = rcu_dereference_check(rcu_torture_current,
888 rcu_read_lock_bh_held() ||
889 rcu_read_lock_sched_held() ||
890 srcu_read_lock_held(&srcu_ctl));
891 if (p == NULL) {
892 /* Wait for rcu_torture_writer to get underway */
893 cur_ops->readunlock(idx);
894 schedule_timeout_interruptible(HZ);
895 continue;
896 }
897 if (p->rtort_mbtest == 0)
898 atomic_inc(&n_rcu_torture_mberror);
899 cur_ops->read_delay(&rand);
900 preempt_disable();
901 pipe_count = p->rtort_pipe_count;
902 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
903 /* Should not happen, but... */
904 pipe_count = RCU_TORTURE_PIPE_LEN;
905 }
906 completed_end = cur_ops->completed();
907 if (pipe_count > 1) {
908 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
909 ts, completed, completed_end);
910 rcutorture_trace_dump();
911 }
912 __this_cpu_inc(rcu_torture_count[pipe_count]);
913 completed = completed_end - completed;
914 if (completed > RCU_TORTURE_PIPE_LEN) {
915 /* Should not happen, but... */
916 completed = RCU_TORTURE_PIPE_LEN;
917 }
918 __this_cpu_inc(rcu_torture_batch[completed]);
919 preempt_enable();
920 cur_ops->readunlock(idx);
921 schedule();
922 stutter_wait("rcu_torture_reader");
923 } while (!torture_must_stop());
924 if (irqreader && cur_ops->irq_capable)
925 del_timer_sync(&t);
926 torture_kthread_stopping("rcu_torture_reader");
927 return 0;
928}
929
930/*
931 * Create an RCU-torture statistics message in the specified buffer.
932 */
933static void
934rcu_torture_printk(char *page)
935{
936 int cpu;
937 int i;
938 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
939 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
940
941 for_each_possible_cpu(cpu) {
942 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
943 pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
944 batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
945 }
946 }
947 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
948 if (pipesummary[i] != 0)
949 break;
950 }
951 page += sprintf(page, "%s%s ", torture_type, TORTURE_FLAG);
952 page += sprintf(page,
953 "rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
954 rcu_torture_current,
955 rcu_torture_current_version,
956 list_empty(&rcu_torture_freelist),
957 atomic_read(&n_rcu_torture_alloc),
958 atomic_read(&n_rcu_torture_alloc_fail),
959 atomic_read(&n_rcu_torture_free));
960 page += sprintf(page, "rtmbe: %d rtbke: %ld rtbre: %ld ",
961 atomic_read(&n_rcu_torture_mberror),
962 n_rcu_torture_boost_ktrerror,
963 n_rcu_torture_boost_rterror);
964 page += sprintf(page, "rtbf: %ld rtb: %ld nt: %ld ",
965 n_rcu_torture_boost_failure,
966 n_rcu_torture_boosts,
967 n_rcu_torture_timers);
968 page = torture_onoff_stats(page);
969 page += sprintf(page, "barrier: %ld/%ld:%ld",
970 n_barrier_successes,
971 n_barrier_attempts,
972 n_rcu_torture_barrier_error);
973 page += sprintf(page, "\n%s%s ", torture_type, TORTURE_FLAG);
974 if (atomic_read(&n_rcu_torture_mberror) != 0 ||
975 n_rcu_torture_barrier_error != 0 ||
976 n_rcu_torture_boost_ktrerror != 0 ||
977 n_rcu_torture_boost_rterror != 0 ||
978 n_rcu_torture_boost_failure != 0 ||
979 i > 1) {
980 page += sprintf(page, "!!! ");
981 atomic_inc(&n_rcu_torture_error);
982 WARN_ON_ONCE(1);
983 }
984 page += sprintf(page, "Reader Pipe: ");
985 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
986 page += sprintf(page, " %ld", pipesummary[i]);
987 page += sprintf(page, "\n%s%s ", torture_type, TORTURE_FLAG);
988 page += sprintf(page, "Reader Batch: ");
989 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
990 page += sprintf(page, " %ld", batchsummary[i]);
991 page += sprintf(page, "\n%s%s ", torture_type, TORTURE_FLAG);
992 page += sprintf(page, "Free-Block Circulation: ");
993 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
994 page += sprintf(page, " %d",
995 atomic_read(&rcu_torture_wcount[i]));
996 }
997 page += sprintf(page, "\n");
998 if (cur_ops->stats)
999 cur_ops->stats(page);
1000}
1001
1002/*
1003 * Print torture statistics. Caller must ensure that there is only
1004 * one call to this function at a given time!!! This is normally
1005 * accomplished by relying on the module system to only have one copy
1006 * of the module loaded, and then by giving the rcu_torture_stats
1007 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1008 * thread is not running).
1009 */
1010static void
1011rcu_torture_stats_print(void)
1012{
1013 int size = nr_cpu_ids * 200 + 8192;
1014 char *buf;
1015
1016 buf = kmalloc(size, GFP_KERNEL);
1017 if (!buf) {
1018 pr_err("rcu-torture: Out of memory, need: %d", size);
1019 return;
1020 }
1021 rcu_torture_printk(buf);
1022 pr_alert("%s", buf);
1023 kfree(buf);
1024}
1025
1026/*
1027 * Periodically prints torture statistics, if periodic statistics printing
1028 * was specified via the stat_interval module parameter.
1029 */
1030static int
1031rcu_torture_stats(void *arg)
1032{
1033 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1034 do {
1035 schedule_timeout_interruptible(stat_interval * HZ);
1036 rcu_torture_stats_print();
1037 torture_shutdown_absorb("rcu_torture_stats");
1038 } while (!torture_must_stop());
1039 torture_kthread_stopping("rcu_torture_stats");
1040 return 0;
1041}
1042
1043static inline void
1044rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1045{
1046 pr_alert("%s" TORTURE_FLAG
1047 "--- %s: nreaders=%d nfakewriters=%d "
1048 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1049 "shuffle_interval=%d stutter=%d irqreader=%d "
1050 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1051 "test_boost=%d/%d test_boost_interval=%d "
1052 "test_boost_duration=%d shutdown_secs=%d "
1053 "stall_cpu=%d stall_cpu_holdoff=%d "
1054 "n_barrier_cbs=%d "
1055 "onoff_interval=%d onoff_holdoff=%d\n",
1056 torture_type, tag, nrealreaders, nfakewriters,
1057 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1058 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1059 test_boost, cur_ops->can_boost,
1060 test_boost_interval, test_boost_duration, shutdown_secs,
1061 stall_cpu, stall_cpu_holdoff,
1062 n_barrier_cbs,
1063 onoff_interval, onoff_holdoff);
1064}
1065
1066static void rcutorture_booster_cleanup(int cpu)
1067{
1068 struct task_struct *t;
1069
1070 if (boost_tasks[cpu] == NULL)
1071 return;
1072 mutex_lock(&boost_mutex);
1073 t = boost_tasks[cpu];
1074 boost_tasks[cpu] = NULL;
1075 mutex_unlock(&boost_mutex);
1076
1077 /* This must be outside of the mutex, otherwise deadlock! */
1078 torture_stop_kthread(rcu_torture_boost, t);
1079}
1080
1081static int rcutorture_booster_init(int cpu)
1082{
1083 int retval;
1084
1085 if (boost_tasks[cpu] != NULL)
1086 return 0; /* Already created, nothing more to do. */
1087
1088 /* Don't allow time recalculation while creating a new task. */
1089 mutex_lock(&boost_mutex);
1090 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
1091 boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
1092 cpu_to_node(cpu),
1093 "rcu_torture_boost");
1094 if (IS_ERR(boost_tasks[cpu])) {
1095 retval = PTR_ERR(boost_tasks[cpu]);
1096 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
1097 n_rcu_torture_boost_ktrerror++;
1098 boost_tasks[cpu] = NULL;
1099 mutex_unlock(&boost_mutex);
1100 return retval;
1101 }
1102 kthread_bind(boost_tasks[cpu], cpu);
1103 wake_up_process(boost_tasks[cpu]);
1104 mutex_unlock(&boost_mutex);
1105 return 0;
1106}
1107
1108/*
1109 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
1110 * induces a CPU stall for the time specified by stall_cpu.
1111 */
1112static int rcu_torture_stall(void *args)
1113{
1114 unsigned long stop_at;
1115
1116 VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
1117 if (stall_cpu_holdoff > 0) {
1118 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
1119 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
1120 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
1121 }
1122 if (!kthread_should_stop()) {
1123 stop_at = get_seconds() + stall_cpu;
1124 /* RCU CPU stall is expected behavior in following code. */
1125 pr_alert("rcu_torture_stall start.\n");
1126 rcu_read_lock();
1127 preempt_disable();
1128 while (ULONG_CMP_LT(get_seconds(), stop_at))
1129 continue; /* Induce RCU CPU stall warning. */
1130 preempt_enable();
1131 rcu_read_unlock();
1132 pr_alert("rcu_torture_stall end.\n");
1133 }
1134 torture_shutdown_absorb("rcu_torture_stall");
1135 while (!kthread_should_stop())
1136 schedule_timeout_interruptible(10 * HZ);
1137 return 0;
1138}
1139
1140/* Spawn CPU-stall kthread, if stall_cpu specified. */
1141static int __init rcu_torture_stall_init(void)
1142{
1143 if (stall_cpu <= 0)
1144 return 0;
1145 return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
1146}
1147
1148/* Callback function for RCU barrier testing. */
1149void rcu_torture_barrier_cbf(struct rcu_head *rcu)
1150{
1151 atomic_inc(&barrier_cbs_invoked);
1152}
1153
1154/* kthread function to register callbacks used to test RCU barriers. */
1155static int rcu_torture_barrier_cbs(void *arg)
1156{
1157 long myid = (long)arg;
1158 bool lastphase = 0;
1159 bool newphase;
1160 struct rcu_head rcu;
1161
1162 init_rcu_head_on_stack(&rcu);
1163 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
1164 set_user_nice(current, MAX_NICE);
1165 do {
1166 wait_event(barrier_cbs_wq[myid],
1167 (newphase =
1168 ACCESS_ONCE(barrier_phase)) != lastphase ||
1169 torture_must_stop());
1170 lastphase = newphase;
1171 smp_mb(); /* ensure barrier_phase load before ->call(). */
1172 if (torture_must_stop())
1173 break;
1174 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
1175 if (atomic_dec_and_test(&barrier_cbs_count))
1176 wake_up(&barrier_wq);
1177 } while (!torture_must_stop());
1178 cur_ops->cb_barrier();
1179 destroy_rcu_head_on_stack(&rcu);
1180 torture_kthread_stopping("rcu_torture_barrier_cbs");
1181 return 0;
1182}
1183
1184/* kthread function to drive and coordinate RCU barrier testing. */
1185static int rcu_torture_barrier(void *arg)
1186{
1187 int i;
1188
1189 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
1190 do {
1191 atomic_set(&barrier_cbs_invoked, 0);
1192 atomic_set(&barrier_cbs_count, n_barrier_cbs);
1193 smp_mb(); /* Ensure barrier_phase after prior assignments. */
1194 barrier_phase = !barrier_phase;
1195 for (i = 0; i < n_barrier_cbs; i++)
1196 wake_up(&barrier_cbs_wq[i]);
1197 wait_event(barrier_wq,
1198 atomic_read(&barrier_cbs_count) == 0 ||
1199 torture_must_stop());
1200 if (torture_must_stop())
1201 break;
1202 n_barrier_attempts++;
1203 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
1204 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
1205 n_rcu_torture_barrier_error++;
1206 WARN_ON_ONCE(1);
1207 }
1208 n_barrier_successes++;
1209 schedule_timeout_interruptible(HZ / 10);
1210 } while (!torture_must_stop());
1211 torture_kthread_stopping("rcu_torture_barrier");
1212 return 0;
1213}
1214
1215/* Initialize RCU barrier testing. */
1216static int rcu_torture_barrier_init(void)
1217{
1218 int i;
1219 int ret;
1220
1221 if (n_barrier_cbs == 0)
1222 return 0;
1223 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
1224 pr_alert("%s" TORTURE_FLAG
1225 " Call or barrier ops missing for %s,\n",
1226 torture_type, cur_ops->name);
1227 pr_alert("%s" TORTURE_FLAG
1228 " RCU barrier testing omitted from run.\n",
1229 torture_type);
1230 return 0;
1231 }
1232 atomic_set(&barrier_cbs_count, 0);
1233 atomic_set(&barrier_cbs_invoked, 0);
1234 barrier_cbs_tasks =
1235 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_tasks[0]),
1236 GFP_KERNEL);
1237 barrier_cbs_wq =
1238 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_wq[0]),
1239 GFP_KERNEL);
1240 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
1241 return -ENOMEM;
1242 for (i = 0; i < n_barrier_cbs; i++) {
1243 init_waitqueue_head(&barrier_cbs_wq[i]);
1244 ret = torture_create_kthread(rcu_torture_barrier_cbs,
1245 (void *)(long)i,
1246 barrier_cbs_tasks[i]);
1247 if (ret)
1248 return ret;
1249 }
1250 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
1251}
1252
1253/* Clean up after RCU barrier testing. */
1254static void rcu_torture_barrier_cleanup(void)
1255{
1256 int i;
1257
1258 torture_stop_kthread(rcu_torture_barrier, barrier_task);
1259 if (barrier_cbs_tasks != NULL) {
1260 for (i = 0; i < n_barrier_cbs; i++)
1261 torture_stop_kthread(rcu_torture_barrier_cbs,
1262 barrier_cbs_tasks[i]);
1263 kfree(barrier_cbs_tasks);
1264 barrier_cbs_tasks = NULL;
1265 }
1266 if (barrier_cbs_wq != NULL) {
1267 kfree(barrier_cbs_wq);
1268 barrier_cbs_wq = NULL;
1269 }
1270}
1271
1272static int rcutorture_cpu_notify(struct notifier_block *self,
1273 unsigned long action, void *hcpu)
1274{
1275 long cpu = (long)hcpu;
1276
1277 switch (action) {
1278 case CPU_ONLINE:
1279 case CPU_DOWN_FAILED:
1280 (void)rcutorture_booster_init(cpu);
1281 break;
1282 case CPU_DOWN_PREPARE:
1283 rcutorture_booster_cleanup(cpu);
1284 break;
1285 default:
1286 break;
1287 }
1288 return NOTIFY_OK;
1289}
1290
1291static struct notifier_block rcutorture_cpu_nb = {
1292 .notifier_call = rcutorture_cpu_notify,
1293};
1294
1295static void
1296rcu_torture_cleanup(void)
1297{
1298 int i;
1299
1300 rcutorture_record_test_transition();
1301 if (torture_cleanup()) {
1302 if (cur_ops->cb_barrier != NULL)
1303 cur_ops->cb_barrier();
1304 return;
1305 }
1306
1307 rcu_torture_barrier_cleanup();
1308 torture_stop_kthread(rcu_torture_stall, stall_task);
1309 torture_stop_kthread(rcu_torture_writer, writer_task);
1310
1311 if (reader_tasks) {
1312 for (i = 0; i < nrealreaders; i++)
1313 torture_stop_kthread(rcu_torture_reader,
1314 reader_tasks[i]);
1315 kfree(reader_tasks);
1316 }
1317 rcu_torture_current = NULL;
1318
1319 if (fakewriter_tasks) {
1320 for (i = 0; i < nfakewriters; i++) {
1321 torture_stop_kthread(rcu_torture_fakewriter,
1322 fakewriter_tasks[i]);
1323 }
1324 kfree(fakewriter_tasks);
1325 fakewriter_tasks = NULL;
1326 }
1327
1328 torture_stop_kthread(rcu_torture_stats, stats_task);
1329 torture_stop_kthread(rcu_torture_fqs, fqs_task);
1330 if ((test_boost == 1 && cur_ops->can_boost) ||
1331 test_boost == 2) {
1332 unregister_cpu_notifier(&rcutorture_cpu_nb);
1333 for_each_possible_cpu(i)
1334 rcutorture_booster_cleanup(i);
1335 }
1336
1337 /* Wait for all RCU callbacks to fire. */
1338
1339 if (cur_ops->cb_barrier != NULL)
1340 cur_ops->cb_barrier();
1341
1342 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
1343
1344 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
1345 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
1346 else if (torture_onoff_failures())
1347 rcu_torture_print_module_parms(cur_ops,
1348 "End of test: RCU_HOTPLUG");
1349 else
1350 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
1351}
1352
1353#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1354static void rcu_torture_leak_cb(struct rcu_head *rhp)
1355{
1356}
1357
1358static void rcu_torture_err_cb(struct rcu_head *rhp)
1359{
1360 /*
1361 * This -might- happen due to race conditions, but is unlikely.
1362 * The scenario that leads to this happening is that the
1363 * first of the pair of duplicate callbacks is queued,
1364 * someone else starts a grace period that includes that
1365 * callback, then the second of the pair must wait for the
1366 * next grace period. Unlikely, but can happen. If it
1367 * does happen, the debug-objects subsystem won't have splatted.
1368 */
1369 pr_alert("rcutorture: duplicated callback was invoked.\n");
1370}
1371#endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1372
1373/*
1374 * Verify that double-free causes debug-objects to complain, but only
1375 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
1376 * cannot be carried out.
1377 */
1378static void rcu_test_debug_objects(void)
1379{
1380#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1381 struct rcu_head rh1;
1382 struct rcu_head rh2;
1383
1384 init_rcu_head_on_stack(&rh1);
1385 init_rcu_head_on_stack(&rh2);
1386 pr_alert("rcutorture: WARN: Duplicate call_rcu() test starting.\n");
1387
1388 /* Try to queue the rh2 pair of callbacks for the same grace period. */
1389 preempt_disable(); /* Prevent preemption from interrupting test. */
1390 rcu_read_lock(); /* Make it impossible to finish a grace period. */
1391 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
1392 local_irq_disable(); /* Make it harder to start a new grace period. */
1393 call_rcu(&rh2, rcu_torture_leak_cb);
1394 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
1395 local_irq_enable();
1396 rcu_read_unlock();
1397 preempt_enable();
1398
1399 /* Wait for them all to get done so we can safely return. */
1400 rcu_barrier();
1401 pr_alert("rcutorture: WARN: Duplicate call_rcu() test complete.\n");
1402 destroy_rcu_head_on_stack(&rh1);
1403 destroy_rcu_head_on_stack(&rh2);
1404#else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1405 pr_alert("rcutorture: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n");
1406#endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1407}
1408
1409static int __init
1410rcu_torture_init(void)
1411{
1412 int i;
1413 int cpu;
1414 int firsterr = 0;
1415 static struct rcu_torture_ops *torture_ops[] = {
1416 &rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &sched_ops,
1417 };
1418
1419 torture_init_begin(torture_type, verbose, &rcutorture_runnable);
1420
1421 /* Process args and tell the world that the torturer is on the job. */
1422 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1423 cur_ops = torture_ops[i];
1424 if (strcmp(torture_type, cur_ops->name) == 0)
1425 break;
1426 }
1427 if (i == ARRAY_SIZE(torture_ops)) {
1428 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
1429 torture_type);
1430 pr_alert("rcu-torture types:");
1431 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1432 pr_alert(" %s", torture_ops[i]->name);
1433 pr_alert("\n");
1434 torture_init_end();
1435 return -EINVAL;
1436 }
1437 if (cur_ops->fqs == NULL && fqs_duration != 0) {
1438 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
1439 fqs_duration = 0;
1440 }
1441 if (cur_ops->init)
1442 cur_ops->init(); /* no "goto unwind" prior to this point!!! */
1443
1444 if (nreaders >= 0)
1445 nrealreaders = nreaders;
1446 else
1447 nrealreaders = 2 * num_online_cpus();
1448 rcu_torture_print_module_parms(cur_ops, "Start of test");
1449
1450 /* Set up the freelist. */
1451
1452 INIT_LIST_HEAD(&rcu_torture_freelist);
1453 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1454 rcu_tortures[i].rtort_mbtest = 0;
1455 list_add_tail(&rcu_tortures[i].rtort_free,
1456 &rcu_torture_freelist);
1457 }
1458
1459 /* Initialize the statistics so that each run gets its own numbers. */
1460
1461 rcu_torture_current = NULL;
1462 rcu_torture_current_version = 0;
1463 atomic_set(&n_rcu_torture_alloc, 0);
1464 atomic_set(&n_rcu_torture_alloc_fail, 0);
1465 atomic_set(&n_rcu_torture_free, 0);
1466 atomic_set(&n_rcu_torture_mberror, 0);
1467 atomic_set(&n_rcu_torture_error, 0);
1468 n_rcu_torture_barrier_error = 0;
1469 n_rcu_torture_boost_ktrerror = 0;
1470 n_rcu_torture_boost_rterror = 0;
1471 n_rcu_torture_boost_failure = 0;
1472 n_rcu_torture_boosts = 0;
1473 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1474 atomic_set(&rcu_torture_wcount[i], 0);
1475 for_each_possible_cpu(cpu) {
1476 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1477 per_cpu(rcu_torture_count, cpu)[i] = 0;
1478 per_cpu(rcu_torture_batch, cpu)[i] = 0;
1479 }
1480 }
1481
1482 /* Start up the kthreads. */
1483
1484 firsterr = torture_create_kthread(rcu_torture_writer, NULL,
1485 writer_task);
1486 if (firsterr)
1487 goto unwind;
1488 fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]),
1489 GFP_KERNEL);
1490 if (fakewriter_tasks == NULL) {
1491 VERBOSE_TOROUT_ERRSTRING("out of memory");
1492 firsterr = -ENOMEM;
1493 goto unwind;
1494 }
1495 for (i = 0; i < nfakewriters; i++) {
1496 firsterr = torture_create_kthread(rcu_torture_fakewriter,
1497 NULL, fakewriter_tasks[i]);
1498 if (firsterr)
1499 goto unwind;
1500 }
1501 reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
1502 GFP_KERNEL);
1503 if (reader_tasks == NULL) {
1504 VERBOSE_TOROUT_ERRSTRING("out of memory");
1505 firsterr = -ENOMEM;
1506 goto unwind;
1507 }
1508 for (i = 0; i < nrealreaders; i++) {
1509 firsterr = torture_create_kthread(rcu_torture_reader, NULL,
1510 reader_tasks[i]);
1511 if (firsterr)
1512 goto unwind;
1513 }
1514 if (stat_interval > 0) {
1515 firsterr = torture_create_kthread(rcu_torture_stats, NULL,
1516 stats_task);
1517 if (firsterr)
1518 goto unwind;
1519 }
1520 if (test_no_idle_hz) {
1521 firsterr = torture_shuffle_init(shuffle_interval * HZ);
1522 if (firsterr)
1523 goto unwind;
1524 }
1525 if (stutter < 0)
1526 stutter = 0;
1527 if (stutter) {
1528 firsterr = torture_stutter_init(stutter * HZ);
1529 if (firsterr)
1530 goto unwind;
1531 }
1532 if (fqs_duration < 0)
1533 fqs_duration = 0;
1534 if (fqs_duration) {
1535 /* Create the fqs thread */
1536 torture_create_kthread(rcu_torture_fqs, NULL, fqs_task);
1537 if (firsterr)
1538 goto unwind;
1539 }
1540 if (test_boost_interval < 1)
1541 test_boost_interval = 1;
1542 if (test_boost_duration < 2)
1543 test_boost_duration = 2;
1544 if ((test_boost == 1 && cur_ops->can_boost) ||
1545 test_boost == 2) {
1546
1547 boost_starttime = jiffies + test_boost_interval * HZ;
1548 register_cpu_notifier(&rcutorture_cpu_nb);
1549 for_each_possible_cpu(i) {
1550 if (cpu_is_offline(i))
1551 continue; /* Heuristic: CPU can go offline. */
1552 firsterr = rcutorture_booster_init(i);
1553 if (firsterr)
1554 goto unwind;
1555 }
1556 }
1557 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
1558 if (firsterr)
1559 goto unwind;
1560 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval * HZ);
1561 if (firsterr)
1562 goto unwind;
1563 firsterr = rcu_torture_stall_init();
1564 if (firsterr)
1565 goto unwind;
1566 firsterr = rcu_torture_barrier_init();
1567 if (firsterr)
1568 goto unwind;
1569 if (object_debug)
1570 rcu_test_debug_objects();
1571 rcutorture_record_test_transition();
1572 torture_init_end();
1573 return 0;
1574
1575unwind:
1576 torture_init_end();
1577 rcu_torture_cleanup();
1578 return firsterr;
1579}
1580
1581module_init(rcu_torture_init);
1582module_exit(rcu_torture_cleanup);
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Read-Copy Update module-based torture test facility
4 *
5 * Copyright (C) IBM Corporation, 2005, 2006
6 *
7 * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
8 * Josh Triplett <josh@joshtriplett.org>
9 *
10 * See also: Documentation/RCU/torture.rst
11 */
12
13#define pr_fmt(fmt) fmt
14
15#include <linux/types.h>
16#include <linux/kernel.h>
17#include <linux/init.h>
18#include <linux/module.h>
19#include <linux/kthread.h>
20#include <linux/err.h>
21#include <linux/spinlock.h>
22#include <linux/smp.h>
23#include <linux/rcupdate_wait.h>
24#include <linux/interrupt.h>
25#include <linux/sched/signal.h>
26#include <uapi/linux/sched/types.h>
27#include <linux/atomic.h>
28#include <linux/bitops.h>
29#include <linux/completion.h>
30#include <linux/moduleparam.h>
31#include <linux/percpu.h>
32#include <linux/notifier.h>
33#include <linux/reboot.h>
34#include <linux/freezer.h>
35#include <linux/cpu.h>
36#include <linux/delay.h>
37#include <linux/stat.h>
38#include <linux/srcu.h>
39#include <linux/slab.h>
40#include <linux/trace_clock.h>
41#include <asm/byteorder.h>
42#include <linux/torture.h>
43#include <linux/vmalloc.h>
44#include <linux/sched/debug.h>
45#include <linux/sched/sysctl.h>
46#include <linux/oom.h>
47#include <linux/tick.h>
48#include <linux/rcupdate_trace.h>
49#include <linux/nmi.h>
50
51#include "rcu.h"
52
53MODULE_LICENSE("GPL");
54MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
55
56/* Bits for ->extendables field, extendables param, and related definitions. */
57#define RCUTORTURE_RDR_SHIFT_1 8 /* Put SRCU index in upper bits. */
58#define RCUTORTURE_RDR_MASK_1 (1 << RCUTORTURE_RDR_SHIFT_1)
59#define RCUTORTURE_RDR_SHIFT_2 9 /* Put SRCU index in upper bits. */
60#define RCUTORTURE_RDR_MASK_2 (1 << RCUTORTURE_RDR_SHIFT_2)
61#define RCUTORTURE_RDR_BH 0x01 /* Extend readers by disabling bh. */
62#define RCUTORTURE_RDR_IRQ 0x02 /* ... disabling interrupts. */
63#define RCUTORTURE_RDR_PREEMPT 0x04 /* ... disabling preemption. */
64#define RCUTORTURE_RDR_RBH 0x08 /* ... rcu_read_lock_bh(). */
65#define RCUTORTURE_RDR_SCHED 0x10 /* ... rcu_read_lock_sched(). */
66#define RCUTORTURE_RDR_RCU_1 0x20 /* ... entering another RCU reader. */
67#define RCUTORTURE_RDR_RCU_2 0x40 /* ... entering another RCU reader. */
68#define RCUTORTURE_RDR_NBITS 7 /* Number of bits defined above. */
69#define RCUTORTURE_MAX_EXTEND \
70 (RCUTORTURE_RDR_BH | RCUTORTURE_RDR_IRQ | RCUTORTURE_RDR_PREEMPT | \
71 RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED)
72#define RCUTORTURE_RDR_MAX_LOOPS 0x7 /* Maximum reader extensions. */
73 /* Must be power of two minus one. */
74#define RCUTORTURE_RDR_MAX_SEGS (RCUTORTURE_RDR_MAX_LOOPS + 3)
75
76torture_param(int, extendables, RCUTORTURE_MAX_EXTEND,
77 "Extend readers by disabling bh (1), irqs (2), or preempt (4)");
78torture_param(int, fqs_duration, 0, "Duration of fqs bursts (us), 0 to disable");
79torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
80torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
81torture_param(int, fwd_progress, 1, "Number of grace-period forward progress tasks (0 to disable)");
82torture_param(int, fwd_progress_div, 4, "Fraction of CPU stall to wait");
83torture_param(int, fwd_progress_holdoff, 60, "Time between forward-progress tests (s)");
84torture_param(bool, fwd_progress_need_resched, 1, "Hide cond_resched() behind need_resched()");
85torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
86torture_param(bool, gp_cond_exp, false, "Use conditional/async expedited GP wait primitives");
87torture_param(bool, gp_cond_full, false, "Use conditional/async full-state GP wait primitives");
88torture_param(bool, gp_cond_exp_full, false,
89 "Use conditional/async full-stateexpedited GP wait primitives");
90torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
91torture_param(bool, gp_normal, false, "Use normal (non-expedited) GP wait primitives");
92torture_param(bool, gp_poll, false, "Use polling GP wait primitives");
93torture_param(bool, gp_poll_exp, false, "Use polling expedited GP wait primitives");
94torture_param(bool, gp_poll_full, false, "Use polling full-state GP wait primitives");
95torture_param(bool, gp_poll_exp_full, false, "Use polling full-state expedited GP wait primitives");
96torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
97torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
98torture_param(int, leakpointer, 0, "Leak pointer dereferences from readers");
99torture_param(int, n_barrier_cbs, 0, "# of callbacks/kthreads for barrier testing");
100torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
101torture_param(int, nreaders, -1, "Number of RCU reader threads");
102torture_param(int, object_debug, 0, "Enable debug-object double call_rcu() testing");
103torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
104torture_param(int, onoff_interval, 0, "Time between CPU hotplugs (jiffies), 0=disable");
105torture_param(int, nocbs_nthreads, 0, "Number of NOCB toggle threads, 0 to disable");
106torture_param(int, nocbs_toggle, 1000, "Time between toggling nocb state (ms)");
107torture_param(int, read_exit_delay, 13, "Delay between read-then-exit episodes (s)");
108torture_param(int, read_exit_burst, 16, "# of read-then-exit bursts per episode, zero to disable");
109torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
110torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
111torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
112torture_param(int, stall_cpu_holdoff, 10, "Time to wait before starting stall (s).");
113torture_param(bool, stall_no_softlockup, false, "Avoid softlockup warning during cpu stall.");
114torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling.");
115torture_param(int, stall_cpu_block, 0, "Sleep while stalling.");
116torture_param(int, stall_gp_kthread, 0, "Grace-period kthread stall duration (s).");
117torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s");
118torture_param(int, stutter, 5, "Number of seconds to run/halt test");
119torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
120torture_param(int, test_boost_duration, 4, "Duration of each boost test, seconds.");
121torture_param(int, test_boost_interval, 7, "Interval between boost tests, seconds.");
122torture_param(bool, test_no_idle_hz, true, "Test support for tickless idle CPUs");
123torture_param(int, verbose, 1, "Enable verbose debugging printk()s");
124
125static char *torture_type = "rcu";
126module_param(torture_type, charp, 0444);
127MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, srcu, ...)");
128
129static int nrealnocbers;
130static int nrealreaders;
131static struct task_struct *writer_task;
132static struct task_struct **fakewriter_tasks;
133static struct task_struct **reader_tasks;
134static struct task_struct **nocb_tasks;
135static struct task_struct *stats_task;
136static struct task_struct *fqs_task;
137static struct task_struct *boost_tasks[NR_CPUS];
138static struct task_struct *stall_task;
139static struct task_struct **fwd_prog_tasks;
140static struct task_struct **barrier_cbs_tasks;
141static struct task_struct *barrier_task;
142static struct task_struct *read_exit_task;
143
144#define RCU_TORTURE_PIPE_LEN 10
145
146// Mailbox-like structure to check RCU global memory ordering.
147struct rcu_torture_reader_check {
148 unsigned long rtc_myloops;
149 int rtc_chkrdr;
150 unsigned long rtc_chkloops;
151 int rtc_ready;
152 struct rcu_torture_reader_check *rtc_assigner;
153} ____cacheline_internodealigned_in_smp;
154
155// Update-side data structure used to check RCU readers.
156struct rcu_torture {
157 struct rcu_head rtort_rcu;
158 int rtort_pipe_count;
159 struct list_head rtort_free;
160 int rtort_mbtest;
161 struct rcu_torture_reader_check *rtort_chkp;
162};
163
164static LIST_HEAD(rcu_torture_freelist);
165static struct rcu_torture __rcu *rcu_torture_current;
166static unsigned long rcu_torture_current_version;
167static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
168static DEFINE_SPINLOCK(rcu_torture_lock);
169static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count);
170static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch);
171static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
172static struct rcu_torture_reader_check *rcu_torture_reader_mbchk;
173static atomic_t n_rcu_torture_alloc;
174static atomic_t n_rcu_torture_alloc_fail;
175static atomic_t n_rcu_torture_free;
176static atomic_t n_rcu_torture_mberror;
177static atomic_t n_rcu_torture_mbchk_fail;
178static atomic_t n_rcu_torture_mbchk_tries;
179static atomic_t n_rcu_torture_error;
180static long n_rcu_torture_barrier_error;
181static long n_rcu_torture_boost_ktrerror;
182static long n_rcu_torture_boost_rterror;
183static long n_rcu_torture_boost_failure;
184static long n_rcu_torture_boosts;
185static atomic_long_t n_rcu_torture_timers;
186static long n_barrier_attempts;
187static long n_barrier_successes; /* did rcu_barrier test succeed? */
188static unsigned long n_read_exits;
189static struct list_head rcu_torture_removed;
190static unsigned long shutdown_jiffies;
191static unsigned long start_gp_seq;
192static atomic_long_t n_nocb_offload;
193static atomic_long_t n_nocb_deoffload;
194
195static int rcu_torture_writer_state;
196#define RTWS_FIXED_DELAY 0
197#define RTWS_DELAY 1
198#define RTWS_REPLACE 2
199#define RTWS_DEF_FREE 3
200#define RTWS_EXP_SYNC 4
201#define RTWS_COND_GET 5
202#define RTWS_COND_GET_FULL 6
203#define RTWS_COND_GET_EXP 7
204#define RTWS_COND_GET_EXP_FULL 8
205#define RTWS_COND_SYNC 9
206#define RTWS_COND_SYNC_FULL 10
207#define RTWS_COND_SYNC_EXP 11
208#define RTWS_COND_SYNC_EXP_FULL 12
209#define RTWS_POLL_GET 13
210#define RTWS_POLL_GET_FULL 14
211#define RTWS_POLL_GET_EXP 15
212#define RTWS_POLL_GET_EXP_FULL 16
213#define RTWS_POLL_WAIT 17
214#define RTWS_POLL_WAIT_FULL 18
215#define RTWS_POLL_WAIT_EXP 19
216#define RTWS_POLL_WAIT_EXP_FULL 20
217#define RTWS_SYNC 21
218#define RTWS_STUTTER 22
219#define RTWS_STOPPING 23
220static const char * const rcu_torture_writer_state_names[] = {
221 "RTWS_FIXED_DELAY",
222 "RTWS_DELAY",
223 "RTWS_REPLACE",
224 "RTWS_DEF_FREE",
225 "RTWS_EXP_SYNC",
226 "RTWS_COND_GET",
227 "RTWS_COND_GET_FULL",
228 "RTWS_COND_GET_EXP",
229 "RTWS_COND_GET_EXP_FULL",
230 "RTWS_COND_SYNC",
231 "RTWS_COND_SYNC_FULL",
232 "RTWS_COND_SYNC_EXP",
233 "RTWS_COND_SYNC_EXP_FULL",
234 "RTWS_POLL_GET",
235 "RTWS_POLL_GET_FULL",
236 "RTWS_POLL_GET_EXP",
237 "RTWS_POLL_GET_EXP_FULL",
238 "RTWS_POLL_WAIT",
239 "RTWS_POLL_WAIT_FULL",
240 "RTWS_POLL_WAIT_EXP",
241 "RTWS_POLL_WAIT_EXP_FULL",
242 "RTWS_SYNC",
243 "RTWS_STUTTER",
244 "RTWS_STOPPING",
245};
246
247/* Record reader segment types and duration for first failing read. */
248struct rt_read_seg {
249 int rt_readstate;
250 unsigned long rt_delay_jiffies;
251 unsigned long rt_delay_ms;
252 unsigned long rt_delay_us;
253 bool rt_preempted;
254};
255static int err_segs_recorded;
256static struct rt_read_seg err_segs[RCUTORTURE_RDR_MAX_SEGS];
257static int rt_read_nsegs;
258
259static const char *rcu_torture_writer_state_getname(void)
260{
261 unsigned int i = READ_ONCE(rcu_torture_writer_state);
262
263 if (i >= ARRAY_SIZE(rcu_torture_writer_state_names))
264 return "???";
265 return rcu_torture_writer_state_names[i];
266}
267
268#ifdef CONFIG_RCU_TRACE
269static u64 notrace rcu_trace_clock_local(void)
270{
271 u64 ts = trace_clock_local();
272
273 (void)do_div(ts, NSEC_PER_USEC);
274 return ts;
275}
276#else /* #ifdef CONFIG_RCU_TRACE */
277static u64 notrace rcu_trace_clock_local(void)
278{
279 return 0ULL;
280}
281#endif /* #else #ifdef CONFIG_RCU_TRACE */
282
283/*
284 * Stop aggressive CPU-hog tests a bit before the end of the test in order
285 * to avoid interfering with test shutdown.
286 */
287static bool shutdown_time_arrived(void)
288{
289 return shutdown_secs && time_after(jiffies, shutdown_jiffies - 30 * HZ);
290}
291
292static unsigned long boost_starttime; /* jiffies of next boost test start. */
293static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
294 /* and boost task create/destroy. */
295static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
296static bool barrier_phase; /* Test phase. */
297static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
298static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
299static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
300
301static atomic_t rcu_fwd_cb_nodelay; /* Short rcu_torture_delay() delays. */
302
303/*
304 * Allocate an element from the rcu_tortures pool.
305 */
306static struct rcu_torture *
307rcu_torture_alloc(void)
308{
309 struct list_head *p;
310
311 spin_lock_bh(&rcu_torture_lock);
312 if (list_empty(&rcu_torture_freelist)) {
313 atomic_inc(&n_rcu_torture_alloc_fail);
314 spin_unlock_bh(&rcu_torture_lock);
315 return NULL;
316 }
317 atomic_inc(&n_rcu_torture_alloc);
318 p = rcu_torture_freelist.next;
319 list_del_init(p);
320 spin_unlock_bh(&rcu_torture_lock);
321 return container_of(p, struct rcu_torture, rtort_free);
322}
323
324/*
325 * Free an element to the rcu_tortures pool.
326 */
327static void
328rcu_torture_free(struct rcu_torture *p)
329{
330 atomic_inc(&n_rcu_torture_free);
331 spin_lock_bh(&rcu_torture_lock);
332 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
333 spin_unlock_bh(&rcu_torture_lock);
334}
335
336/*
337 * Operations vector for selecting different types of tests.
338 */
339
340struct rcu_torture_ops {
341 int ttype;
342 void (*init)(void);
343 void (*cleanup)(void);
344 int (*readlock)(void);
345 void (*read_delay)(struct torture_random_state *rrsp,
346 struct rt_read_seg *rtrsp);
347 void (*readunlock)(int idx);
348 int (*readlock_held)(void);
349 unsigned long (*get_gp_seq)(void);
350 unsigned long (*gp_diff)(unsigned long new, unsigned long old);
351 void (*deferred_free)(struct rcu_torture *p);
352 void (*sync)(void);
353 void (*exp_sync)(void);
354 unsigned long (*get_gp_state_exp)(void);
355 unsigned long (*start_gp_poll_exp)(void);
356 void (*start_gp_poll_exp_full)(struct rcu_gp_oldstate *rgosp);
357 bool (*poll_gp_state_exp)(unsigned long oldstate);
358 void (*cond_sync_exp)(unsigned long oldstate);
359 void (*cond_sync_exp_full)(struct rcu_gp_oldstate *rgosp);
360 unsigned long (*get_comp_state)(void);
361 void (*get_comp_state_full)(struct rcu_gp_oldstate *rgosp);
362 bool (*same_gp_state)(unsigned long oldstate1, unsigned long oldstate2);
363 bool (*same_gp_state_full)(struct rcu_gp_oldstate *rgosp1, struct rcu_gp_oldstate *rgosp2);
364 unsigned long (*get_gp_state)(void);
365 void (*get_gp_state_full)(struct rcu_gp_oldstate *rgosp);
366 unsigned long (*get_gp_completed)(void);
367 void (*get_gp_completed_full)(struct rcu_gp_oldstate *rgosp);
368 unsigned long (*start_gp_poll)(void);
369 void (*start_gp_poll_full)(struct rcu_gp_oldstate *rgosp);
370 bool (*poll_gp_state)(unsigned long oldstate);
371 bool (*poll_gp_state_full)(struct rcu_gp_oldstate *rgosp);
372 bool (*poll_need_2gp)(bool poll, bool poll_full);
373 void (*cond_sync)(unsigned long oldstate);
374 void (*cond_sync_full)(struct rcu_gp_oldstate *rgosp);
375 call_rcu_func_t call;
376 void (*cb_barrier)(void);
377 void (*fqs)(void);
378 void (*stats)(void);
379 void (*gp_kthread_dbg)(void);
380 bool (*check_boost_failed)(unsigned long gp_state, int *cpup);
381 int (*stall_dur)(void);
382 long cbflood_max;
383 int irq_capable;
384 int can_boost;
385 int extendables;
386 int slow_gps;
387 int no_pi_lock;
388 const char *name;
389};
390
391static struct rcu_torture_ops *cur_ops;
392
393/*
394 * Definitions for rcu torture testing.
395 */
396
397static int torture_readlock_not_held(void)
398{
399 return rcu_read_lock_bh_held() || rcu_read_lock_sched_held();
400}
401
402static int rcu_torture_read_lock(void) __acquires(RCU)
403{
404 rcu_read_lock();
405 return 0;
406}
407
408static void
409rcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
410{
411 unsigned long started;
412 unsigned long completed;
413 const unsigned long shortdelay_us = 200;
414 unsigned long longdelay_ms = 300;
415 unsigned long long ts;
416
417 /* We want a short delay sometimes to make a reader delay the grace
418 * period, and we want a long delay occasionally to trigger
419 * force_quiescent_state. */
420
421 if (!atomic_read(&rcu_fwd_cb_nodelay) &&
422 !(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) {
423 started = cur_ops->get_gp_seq();
424 ts = rcu_trace_clock_local();
425 if (preempt_count() & (SOFTIRQ_MASK | HARDIRQ_MASK))
426 longdelay_ms = 5; /* Avoid triggering BH limits. */
427 mdelay(longdelay_ms);
428 rtrsp->rt_delay_ms = longdelay_ms;
429 completed = cur_ops->get_gp_seq();
430 do_trace_rcu_torture_read(cur_ops->name, NULL, ts,
431 started, completed);
432 }
433 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) {
434 udelay(shortdelay_us);
435 rtrsp->rt_delay_us = shortdelay_us;
436 }
437 if (!preempt_count() &&
438 !(torture_random(rrsp) % (nrealreaders * 500))) {
439 torture_preempt_schedule(); /* QS only if preemptible. */
440 rtrsp->rt_preempted = true;
441 }
442}
443
444static void rcu_torture_read_unlock(int idx) __releases(RCU)
445{
446 rcu_read_unlock();
447}
448
449/*
450 * Update callback in the pipe. This should be invoked after a grace period.
451 */
452static bool
453rcu_torture_pipe_update_one(struct rcu_torture *rp)
454{
455 int i;
456 struct rcu_torture_reader_check *rtrcp = READ_ONCE(rp->rtort_chkp);
457
458 if (rtrcp) {
459 WRITE_ONCE(rp->rtort_chkp, NULL);
460 smp_store_release(&rtrcp->rtc_ready, 1); // Pair with smp_load_acquire().
461 }
462 i = READ_ONCE(rp->rtort_pipe_count);
463 if (i > RCU_TORTURE_PIPE_LEN)
464 i = RCU_TORTURE_PIPE_LEN;
465 atomic_inc(&rcu_torture_wcount[i]);
466 WRITE_ONCE(rp->rtort_pipe_count, i + 1);
467 if (rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
468 rp->rtort_mbtest = 0;
469 return true;
470 }
471 return false;
472}
473
474/*
475 * Update all callbacks in the pipe. Suitable for synchronous grace-period
476 * primitives.
477 */
478static void
479rcu_torture_pipe_update(struct rcu_torture *old_rp)
480{
481 struct rcu_torture *rp;
482 struct rcu_torture *rp1;
483
484 if (old_rp)
485 list_add(&old_rp->rtort_free, &rcu_torture_removed);
486 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
487 if (rcu_torture_pipe_update_one(rp)) {
488 list_del(&rp->rtort_free);
489 rcu_torture_free(rp);
490 }
491 }
492}
493
494static void
495rcu_torture_cb(struct rcu_head *p)
496{
497 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
498
499 if (torture_must_stop_irq()) {
500 /* Test is ending, just drop callbacks on the floor. */
501 /* The next initialization will pick up the pieces. */
502 return;
503 }
504 if (rcu_torture_pipe_update_one(rp))
505 rcu_torture_free(rp);
506 else
507 cur_ops->deferred_free(rp);
508}
509
510static unsigned long rcu_no_completed(void)
511{
512 return 0;
513}
514
515static void rcu_torture_deferred_free(struct rcu_torture *p)
516{
517 call_rcu_hurry(&p->rtort_rcu, rcu_torture_cb);
518}
519
520static void rcu_sync_torture_init(void)
521{
522 INIT_LIST_HEAD(&rcu_torture_removed);
523}
524
525static bool rcu_poll_need_2gp(bool poll, bool poll_full)
526{
527 return poll;
528}
529
530static struct rcu_torture_ops rcu_ops = {
531 .ttype = RCU_FLAVOR,
532 .init = rcu_sync_torture_init,
533 .readlock = rcu_torture_read_lock,
534 .read_delay = rcu_read_delay,
535 .readunlock = rcu_torture_read_unlock,
536 .readlock_held = torture_readlock_not_held,
537 .get_gp_seq = rcu_get_gp_seq,
538 .gp_diff = rcu_seq_diff,
539 .deferred_free = rcu_torture_deferred_free,
540 .sync = synchronize_rcu,
541 .exp_sync = synchronize_rcu_expedited,
542 .same_gp_state = same_state_synchronize_rcu,
543 .same_gp_state_full = same_state_synchronize_rcu_full,
544 .get_comp_state = get_completed_synchronize_rcu,
545 .get_comp_state_full = get_completed_synchronize_rcu_full,
546 .get_gp_state = get_state_synchronize_rcu,
547 .get_gp_state_full = get_state_synchronize_rcu_full,
548 .get_gp_completed = get_completed_synchronize_rcu,
549 .get_gp_completed_full = get_completed_synchronize_rcu_full,
550 .start_gp_poll = start_poll_synchronize_rcu,
551 .start_gp_poll_full = start_poll_synchronize_rcu_full,
552 .poll_gp_state = poll_state_synchronize_rcu,
553 .poll_gp_state_full = poll_state_synchronize_rcu_full,
554 .poll_need_2gp = rcu_poll_need_2gp,
555 .cond_sync = cond_synchronize_rcu,
556 .cond_sync_full = cond_synchronize_rcu_full,
557 .get_gp_state_exp = get_state_synchronize_rcu,
558 .start_gp_poll_exp = start_poll_synchronize_rcu_expedited,
559 .start_gp_poll_exp_full = start_poll_synchronize_rcu_expedited_full,
560 .poll_gp_state_exp = poll_state_synchronize_rcu,
561 .cond_sync_exp = cond_synchronize_rcu_expedited,
562 .call = call_rcu_hurry,
563 .cb_barrier = rcu_barrier,
564 .fqs = rcu_force_quiescent_state,
565 .stats = NULL,
566 .gp_kthread_dbg = show_rcu_gp_kthreads,
567 .check_boost_failed = rcu_check_boost_fail,
568 .stall_dur = rcu_jiffies_till_stall_check,
569 .irq_capable = 1,
570 .can_boost = IS_ENABLED(CONFIG_RCU_BOOST),
571 .extendables = RCUTORTURE_MAX_EXTEND,
572 .name = "rcu"
573};
574
575/*
576 * Don't even think about trying any of these in real life!!!
577 * The names includes "busted", and they really means it!
578 * The only purpose of these functions is to provide a buggy RCU
579 * implementation to make sure that rcutorture correctly emits
580 * buggy-RCU error messages.
581 */
582static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
583{
584 /* This is a deliberate bug for testing purposes only! */
585 rcu_torture_cb(&p->rtort_rcu);
586}
587
588static void synchronize_rcu_busted(void)
589{
590 /* This is a deliberate bug for testing purposes only! */
591}
592
593static void
594call_rcu_busted(struct rcu_head *head, rcu_callback_t func)
595{
596 /* This is a deliberate bug for testing purposes only! */
597 func(head);
598}
599
600static struct rcu_torture_ops rcu_busted_ops = {
601 .ttype = INVALID_RCU_FLAVOR,
602 .init = rcu_sync_torture_init,
603 .readlock = rcu_torture_read_lock,
604 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
605 .readunlock = rcu_torture_read_unlock,
606 .readlock_held = torture_readlock_not_held,
607 .get_gp_seq = rcu_no_completed,
608 .deferred_free = rcu_busted_torture_deferred_free,
609 .sync = synchronize_rcu_busted,
610 .exp_sync = synchronize_rcu_busted,
611 .call = call_rcu_busted,
612 .cb_barrier = NULL,
613 .fqs = NULL,
614 .stats = NULL,
615 .irq_capable = 1,
616 .name = "busted"
617};
618
619/*
620 * Definitions for srcu torture testing.
621 */
622
623DEFINE_STATIC_SRCU(srcu_ctl);
624static struct srcu_struct srcu_ctld;
625static struct srcu_struct *srcu_ctlp = &srcu_ctl;
626static struct rcu_torture_ops srcud_ops;
627
628static int srcu_torture_read_lock(void) __acquires(srcu_ctlp)
629{
630 if (cur_ops == &srcud_ops)
631 return srcu_read_lock_nmisafe(srcu_ctlp);
632 else
633 return srcu_read_lock(srcu_ctlp);
634}
635
636static void
637srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
638{
639 long delay;
640 const long uspertick = 1000000 / HZ;
641 const long longdelay = 10;
642
643 /* We want there to be long-running readers, but not all the time. */
644
645 delay = torture_random(rrsp) %
646 (nrealreaders * 2 * longdelay * uspertick);
647 if (!delay && in_task()) {
648 schedule_timeout_interruptible(longdelay);
649 rtrsp->rt_delay_jiffies = longdelay;
650 } else {
651 rcu_read_delay(rrsp, rtrsp);
652 }
653}
654
655static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp)
656{
657 if (cur_ops == &srcud_ops)
658 srcu_read_unlock_nmisafe(srcu_ctlp, idx);
659 else
660 srcu_read_unlock(srcu_ctlp, idx);
661}
662
663static int torture_srcu_read_lock_held(void)
664{
665 return srcu_read_lock_held(srcu_ctlp);
666}
667
668static unsigned long srcu_torture_completed(void)
669{
670 return srcu_batches_completed(srcu_ctlp);
671}
672
673static void srcu_torture_deferred_free(struct rcu_torture *rp)
674{
675 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
676}
677
678static void srcu_torture_synchronize(void)
679{
680 synchronize_srcu(srcu_ctlp);
681}
682
683static unsigned long srcu_torture_get_gp_state(void)
684{
685 return get_state_synchronize_srcu(srcu_ctlp);
686}
687
688static unsigned long srcu_torture_start_gp_poll(void)
689{
690 return start_poll_synchronize_srcu(srcu_ctlp);
691}
692
693static bool srcu_torture_poll_gp_state(unsigned long oldstate)
694{
695 return poll_state_synchronize_srcu(srcu_ctlp, oldstate);
696}
697
698static void srcu_torture_call(struct rcu_head *head,
699 rcu_callback_t func)
700{
701 call_srcu(srcu_ctlp, head, func);
702}
703
704static void srcu_torture_barrier(void)
705{
706 srcu_barrier(srcu_ctlp);
707}
708
709static void srcu_torture_stats(void)
710{
711 srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG);
712}
713
714static void srcu_torture_synchronize_expedited(void)
715{
716 synchronize_srcu_expedited(srcu_ctlp);
717}
718
719static struct rcu_torture_ops srcu_ops = {
720 .ttype = SRCU_FLAVOR,
721 .init = rcu_sync_torture_init,
722 .readlock = srcu_torture_read_lock,
723 .read_delay = srcu_read_delay,
724 .readunlock = srcu_torture_read_unlock,
725 .readlock_held = torture_srcu_read_lock_held,
726 .get_gp_seq = srcu_torture_completed,
727 .deferred_free = srcu_torture_deferred_free,
728 .sync = srcu_torture_synchronize,
729 .exp_sync = srcu_torture_synchronize_expedited,
730 .get_gp_state = srcu_torture_get_gp_state,
731 .start_gp_poll = srcu_torture_start_gp_poll,
732 .poll_gp_state = srcu_torture_poll_gp_state,
733 .call = srcu_torture_call,
734 .cb_barrier = srcu_torture_barrier,
735 .stats = srcu_torture_stats,
736 .cbflood_max = 50000,
737 .irq_capable = 1,
738 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
739 .name = "srcu"
740};
741
742static void srcu_torture_init(void)
743{
744 rcu_sync_torture_init();
745 WARN_ON(init_srcu_struct(&srcu_ctld));
746 srcu_ctlp = &srcu_ctld;
747}
748
749static void srcu_torture_cleanup(void)
750{
751 cleanup_srcu_struct(&srcu_ctld);
752 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
753}
754
755/* As above, but dynamically allocated. */
756static struct rcu_torture_ops srcud_ops = {
757 .ttype = SRCU_FLAVOR,
758 .init = srcu_torture_init,
759 .cleanup = srcu_torture_cleanup,
760 .readlock = srcu_torture_read_lock,
761 .read_delay = srcu_read_delay,
762 .readunlock = srcu_torture_read_unlock,
763 .readlock_held = torture_srcu_read_lock_held,
764 .get_gp_seq = srcu_torture_completed,
765 .deferred_free = srcu_torture_deferred_free,
766 .sync = srcu_torture_synchronize,
767 .exp_sync = srcu_torture_synchronize_expedited,
768 .get_gp_state = srcu_torture_get_gp_state,
769 .start_gp_poll = srcu_torture_start_gp_poll,
770 .poll_gp_state = srcu_torture_poll_gp_state,
771 .call = srcu_torture_call,
772 .cb_barrier = srcu_torture_barrier,
773 .stats = srcu_torture_stats,
774 .cbflood_max = 50000,
775 .irq_capable = 1,
776 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
777 .name = "srcud"
778};
779
780/* As above, but broken due to inappropriate reader extension. */
781static struct rcu_torture_ops busted_srcud_ops = {
782 .ttype = SRCU_FLAVOR,
783 .init = srcu_torture_init,
784 .cleanup = srcu_torture_cleanup,
785 .readlock = srcu_torture_read_lock,
786 .read_delay = rcu_read_delay,
787 .readunlock = srcu_torture_read_unlock,
788 .readlock_held = torture_srcu_read_lock_held,
789 .get_gp_seq = srcu_torture_completed,
790 .deferred_free = srcu_torture_deferred_free,
791 .sync = srcu_torture_synchronize,
792 .exp_sync = srcu_torture_synchronize_expedited,
793 .call = srcu_torture_call,
794 .cb_barrier = srcu_torture_barrier,
795 .stats = srcu_torture_stats,
796 .irq_capable = 1,
797 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
798 .extendables = RCUTORTURE_MAX_EXTEND,
799 .name = "busted_srcud"
800};
801
802/*
803 * Definitions for trivial CONFIG_PREEMPT=n-only torture testing.
804 * This implementation does not necessarily work well with CPU hotplug.
805 */
806
807static void synchronize_rcu_trivial(void)
808{
809 int cpu;
810
811 for_each_online_cpu(cpu) {
812 rcutorture_sched_setaffinity(current->pid, cpumask_of(cpu));
813 WARN_ON_ONCE(raw_smp_processor_id() != cpu);
814 }
815}
816
817static int rcu_torture_read_lock_trivial(void) __acquires(RCU)
818{
819 preempt_disable();
820 return 0;
821}
822
823static void rcu_torture_read_unlock_trivial(int idx) __releases(RCU)
824{
825 preempt_enable();
826}
827
828static struct rcu_torture_ops trivial_ops = {
829 .ttype = RCU_TRIVIAL_FLAVOR,
830 .init = rcu_sync_torture_init,
831 .readlock = rcu_torture_read_lock_trivial,
832 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
833 .readunlock = rcu_torture_read_unlock_trivial,
834 .readlock_held = torture_readlock_not_held,
835 .get_gp_seq = rcu_no_completed,
836 .sync = synchronize_rcu_trivial,
837 .exp_sync = synchronize_rcu_trivial,
838 .fqs = NULL,
839 .stats = NULL,
840 .irq_capable = 1,
841 .name = "trivial"
842};
843
844#ifdef CONFIG_TASKS_RCU
845
846/*
847 * Definitions for RCU-tasks torture testing.
848 */
849
850static int tasks_torture_read_lock(void)
851{
852 return 0;
853}
854
855static void tasks_torture_read_unlock(int idx)
856{
857}
858
859static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
860{
861 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
862}
863
864static void synchronize_rcu_mult_test(void)
865{
866 synchronize_rcu_mult(call_rcu_tasks, call_rcu_hurry);
867}
868
869static struct rcu_torture_ops tasks_ops = {
870 .ttype = RCU_TASKS_FLAVOR,
871 .init = rcu_sync_torture_init,
872 .readlock = tasks_torture_read_lock,
873 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
874 .readunlock = tasks_torture_read_unlock,
875 .get_gp_seq = rcu_no_completed,
876 .deferred_free = rcu_tasks_torture_deferred_free,
877 .sync = synchronize_rcu_tasks,
878 .exp_sync = synchronize_rcu_mult_test,
879 .call = call_rcu_tasks,
880 .cb_barrier = rcu_barrier_tasks,
881 .gp_kthread_dbg = show_rcu_tasks_classic_gp_kthread,
882 .fqs = NULL,
883 .stats = NULL,
884 .irq_capable = 1,
885 .slow_gps = 1,
886 .name = "tasks"
887};
888
889#define TASKS_OPS &tasks_ops,
890
891#else // #ifdef CONFIG_TASKS_RCU
892
893#define TASKS_OPS
894
895#endif // #else #ifdef CONFIG_TASKS_RCU
896
897
898#ifdef CONFIG_TASKS_RUDE_RCU
899
900/*
901 * Definitions for rude RCU-tasks torture testing.
902 */
903
904static void rcu_tasks_rude_torture_deferred_free(struct rcu_torture *p)
905{
906 call_rcu_tasks_rude(&p->rtort_rcu, rcu_torture_cb);
907}
908
909static struct rcu_torture_ops tasks_rude_ops = {
910 .ttype = RCU_TASKS_RUDE_FLAVOR,
911 .init = rcu_sync_torture_init,
912 .readlock = rcu_torture_read_lock_trivial,
913 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
914 .readunlock = rcu_torture_read_unlock_trivial,
915 .get_gp_seq = rcu_no_completed,
916 .deferred_free = rcu_tasks_rude_torture_deferred_free,
917 .sync = synchronize_rcu_tasks_rude,
918 .exp_sync = synchronize_rcu_tasks_rude,
919 .call = call_rcu_tasks_rude,
920 .cb_barrier = rcu_barrier_tasks_rude,
921 .gp_kthread_dbg = show_rcu_tasks_rude_gp_kthread,
922 .cbflood_max = 50000,
923 .fqs = NULL,
924 .stats = NULL,
925 .irq_capable = 1,
926 .name = "tasks-rude"
927};
928
929#define TASKS_RUDE_OPS &tasks_rude_ops,
930
931#else // #ifdef CONFIG_TASKS_RUDE_RCU
932
933#define TASKS_RUDE_OPS
934
935#endif // #else #ifdef CONFIG_TASKS_RUDE_RCU
936
937
938#ifdef CONFIG_TASKS_TRACE_RCU
939
940/*
941 * Definitions for tracing RCU-tasks torture testing.
942 */
943
944static int tasks_tracing_torture_read_lock(void)
945{
946 rcu_read_lock_trace();
947 return 0;
948}
949
950static void tasks_tracing_torture_read_unlock(int idx)
951{
952 rcu_read_unlock_trace();
953}
954
955static void rcu_tasks_tracing_torture_deferred_free(struct rcu_torture *p)
956{
957 call_rcu_tasks_trace(&p->rtort_rcu, rcu_torture_cb);
958}
959
960static struct rcu_torture_ops tasks_tracing_ops = {
961 .ttype = RCU_TASKS_TRACING_FLAVOR,
962 .init = rcu_sync_torture_init,
963 .readlock = tasks_tracing_torture_read_lock,
964 .read_delay = srcu_read_delay, /* just reuse srcu's version. */
965 .readunlock = tasks_tracing_torture_read_unlock,
966 .readlock_held = rcu_read_lock_trace_held,
967 .get_gp_seq = rcu_no_completed,
968 .deferred_free = rcu_tasks_tracing_torture_deferred_free,
969 .sync = synchronize_rcu_tasks_trace,
970 .exp_sync = synchronize_rcu_tasks_trace,
971 .call = call_rcu_tasks_trace,
972 .cb_barrier = rcu_barrier_tasks_trace,
973 .gp_kthread_dbg = show_rcu_tasks_trace_gp_kthread,
974 .cbflood_max = 50000,
975 .fqs = NULL,
976 .stats = NULL,
977 .irq_capable = 1,
978 .slow_gps = 1,
979 .name = "tasks-tracing"
980};
981
982#define TASKS_TRACING_OPS &tasks_tracing_ops,
983
984#else // #ifdef CONFIG_TASKS_TRACE_RCU
985
986#define TASKS_TRACING_OPS
987
988#endif // #else #ifdef CONFIG_TASKS_TRACE_RCU
989
990
991static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old)
992{
993 if (!cur_ops->gp_diff)
994 return new - old;
995 return cur_ops->gp_diff(new, old);
996}
997
998/*
999 * RCU torture priority-boost testing. Runs one real-time thread per
1000 * CPU for moderate bursts, repeatedly starting grace periods and waiting
1001 * for them to complete. If a given grace period takes too long, we assume
1002 * that priority inversion has occurred.
1003 */
1004
1005static int old_rt_runtime = -1;
1006
1007static void rcu_torture_disable_rt_throttle(void)
1008{
1009 /*
1010 * Disable RT throttling so that rcutorture's boost threads don't get
1011 * throttled. Only possible if rcutorture is built-in otherwise the
1012 * user should manually do this by setting the sched_rt_period_us and
1013 * sched_rt_runtime sysctls.
1014 */
1015 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime != -1)
1016 return;
1017
1018 old_rt_runtime = sysctl_sched_rt_runtime;
1019 sysctl_sched_rt_runtime = -1;
1020}
1021
1022static void rcu_torture_enable_rt_throttle(void)
1023{
1024 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime == -1)
1025 return;
1026
1027 sysctl_sched_rt_runtime = old_rt_runtime;
1028 old_rt_runtime = -1;
1029}
1030
1031static bool rcu_torture_boost_failed(unsigned long gp_state, unsigned long *start)
1032{
1033 int cpu;
1034 static int dbg_done;
1035 unsigned long end = jiffies;
1036 bool gp_done;
1037 unsigned long j;
1038 static unsigned long last_persist;
1039 unsigned long lp;
1040 unsigned long mininterval = test_boost_duration * HZ - HZ / 2;
1041
1042 if (end - *start > mininterval) {
1043 // Recheck after checking time to avoid false positives.
1044 smp_mb(); // Time check before grace-period check.
1045 if (cur_ops->poll_gp_state(gp_state))
1046 return false; // passed, though perhaps just barely
1047 if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, &cpu)) {
1048 // At most one persisted message per boost test.
1049 j = jiffies;
1050 lp = READ_ONCE(last_persist);
1051 if (time_after(j, lp + mininterval) && cmpxchg(&last_persist, lp, j) == lp)
1052 pr_info("Boost inversion persisted: No QS from CPU %d\n", cpu);
1053 return false; // passed on a technicality
1054 }
1055 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
1056 n_rcu_torture_boost_failure++;
1057 if (!xchg(&dbg_done, 1) && cur_ops->gp_kthread_dbg) {
1058 pr_info("Boost inversion thread ->rt_priority %u gp_state %lu jiffies %lu\n",
1059 current->rt_priority, gp_state, end - *start);
1060 cur_ops->gp_kthread_dbg();
1061 // Recheck after print to flag grace period ending during splat.
1062 gp_done = cur_ops->poll_gp_state(gp_state);
1063 pr_info("Boost inversion: GP %lu %s.\n", gp_state,
1064 gp_done ? "ended already" : "still pending");
1065
1066 }
1067
1068 return true; // failed
1069 } else if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, NULL)) {
1070 *start = jiffies;
1071 }
1072
1073 return false; // passed
1074}
1075
1076static int rcu_torture_boost(void *arg)
1077{
1078 unsigned long endtime;
1079 unsigned long gp_state;
1080 unsigned long gp_state_time;
1081 unsigned long oldstarttime;
1082
1083 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
1084
1085 /* Set real-time priority. */
1086 sched_set_fifo_low(current);
1087
1088 /* Each pass through the following loop does one boost-test cycle. */
1089 do {
1090 bool failed = false; // Test failed already in this test interval
1091 bool gp_initiated = false;
1092
1093 if (kthread_should_stop())
1094 goto checkwait;
1095
1096 /* Wait for the next test interval. */
1097 oldstarttime = READ_ONCE(boost_starttime);
1098 while (time_before(jiffies, oldstarttime)) {
1099 schedule_timeout_interruptible(oldstarttime - jiffies);
1100 if (stutter_wait("rcu_torture_boost"))
1101 sched_set_fifo_low(current);
1102 if (torture_must_stop())
1103 goto checkwait;
1104 }
1105
1106 // Do one boost-test interval.
1107 endtime = oldstarttime + test_boost_duration * HZ;
1108 while (time_before(jiffies, endtime)) {
1109 // Has current GP gone too long?
1110 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state))
1111 failed = rcu_torture_boost_failed(gp_state, &gp_state_time);
1112 // If we don't have a grace period in flight, start one.
1113 if (!gp_initiated || cur_ops->poll_gp_state(gp_state)) {
1114 gp_state = cur_ops->start_gp_poll();
1115 gp_initiated = true;
1116 gp_state_time = jiffies;
1117 }
1118 if (stutter_wait("rcu_torture_boost")) {
1119 sched_set_fifo_low(current);
1120 // If the grace period already ended,
1121 // we don't know when that happened, so
1122 // start over.
1123 if (cur_ops->poll_gp_state(gp_state))
1124 gp_initiated = false;
1125 }
1126 if (torture_must_stop())
1127 goto checkwait;
1128 }
1129
1130 // In case the grace period extended beyond the end of the loop.
1131 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state))
1132 rcu_torture_boost_failed(gp_state, &gp_state_time);
1133
1134 /*
1135 * Set the start time of the next test interval.
1136 * Yes, this is vulnerable to long delays, but such
1137 * delays simply cause a false negative for the next
1138 * interval. Besides, we are running at RT priority,
1139 * so delays should be relatively rare.
1140 */
1141 while (oldstarttime == READ_ONCE(boost_starttime) && !kthread_should_stop()) {
1142 if (mutex_trylock(&boost_mutex)) {
1143 if (oldstarttime == boost_starttime) {
1144 WRITE_ONCE(boost_starttime,
1145 jiffies + test_boost_interval * HZ);
1146 n_rcu_torture_boosts++;
1147 }
1148 mutex_unlock(&boost_mutex);
1149 break;
1150 }
1151 schedule_timeout_uninterruptible(1);
1152 }
1153
1154 /* Go do the stutter. */
1155checkwait: if (stutter_wait("rcu_torture_boost"))
1156 sched_set_fifo_low(current);
1157 } while (!torture_must_stop());
1158
1159 /* Clean up and exit. */
1160 while (!kthread_should_stop()) {
1161 torture_shutdown_absorb("rcu_torture_boost");
1162 schedule_timeout_uninterruptible(1);
1163 }
1164 torture_kthread_stopping("rcu_torture_boost");
1165 return 0;
1166}
1167
1168/*
1169 * RCU torture force-quiescent-state kthread. Repeatedly induces
1170 * bursts of calls to force_quiescent_state(), increasing the probability
1171 * of occurrence of some important types of race conditions.
1172 */
1173static int
1174rcu_torture_fqs(void *arg)
1175{
1176 unsigned long fqs_resume_time;
1177 int fqs_burst_remaining;
1178 int oldnice = task_nice(current);
1179
1180 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
1181 do {
1182 fqs_resume_time = jiffies + fqs_stutter * HZ;
1183 while (time_before(jiffies, fqs_resume_time) &&
1184 !kthread_should_stop()) {
1185 schedule_timeout_interruptible(1);
1186 }
1187 fqs_burst_remaining = fqs_duration;
1188 while (fqs_burst_remaining > 0 &&
1189 !kthread_should_stop()) {
1190 cur_ops->fqs();
1191 udelay(fqs_holdoff);
1192 fqs_burst_remaining -= fqs_holdoff;
1193 }
1194 if (stutter_wait("rcu_torture_fqs"))
1195 sched_set_normal(current, oldnice);
1196 } while (!torture_must_stop());
1197 torture_kthread_stopping("rcu_torture_fqs");
1198 return 0;
1199}
1200
1201// Used by writers to randomly choose from the available grace-period primitives.
1202static int synctype[ARRAY_SIZE(rcu_torture_writer_state_names)] = { };
1203static int nsynctypes;
1204
1205/*
1206 * Determine which grace-period primitives are available.
1207 */
1208static void rcu_torture_write_types(void)
1209{
1210 bool gp_cond1 = gp_cond, gp_cond_exp1 = gp_cond_exp, gp_cond_full1 = gp_cond_full;
1211 bool gp_cond_exp_full1 = gp_cond_exp_full, gp_exp1 = gp_exp, gp_poll_exp1 = gp_poll_exp;
1212 bool gp_poll_exp_full1 = gp_poll_exp_full, gp_normal1 = gp_normal, gp_poll1 = gp_poll;
1213 bool gp_poll_full1 = gp_poll_full, gp_sync1 = gp_sync;
1214
1215 /* Initialize synctype[] array. If none set, take default. */
1216 if (!gp_cond1 &&
1217 !gp_cond_exp1 &&
1218 !gp_cond_full1 &&
1219 !gp_cond_exp_full1 &&
1220 !gp_exp1 &&
1221 !gp_poll_exp1 &&
1222 !gp_poll_exp_full1 &&
1223 !gp_normal1 &&
1224 !gp_poll1 &&
1225 !gp_poll_full1 &&
1226 !gp_sync1) {
1227 gp_cond1 = true;
1228 gp_cond_exp1 = true;
1229 gp_cond_full1 = true;
1230 gp_cond_exp_full1 = true;
1231 gp_exp1 = true;
1232 gp_poll_exp1 = true;
1233 gp_poll_exp_full1 = true;
1234 gp_normal1 = true;
1235 gp_poll1 = true;
1236 gp_poll_full1 = true;
1237 gp_sync1 = true;
1238 }
1239 if (gp_cond1 && cur_ops->get_gp_state && cur_ops->cond_sync) {
1240 synctype[nsynctypes++] = RTWS_COND_GET;
1241 pr_info("%s: Testing conditional GPs.\n", __func__);
1242 } else if (gp_cond && (!cur_ops->get_gp_state || !cur_ops->cond_sync)) {
1243 pr_alert("%s: gp_cond without primitives.\n", __func__);
1244 }
1245 if (gp_cond_exp1 && cur_ops->get_gp_state_exp && cur_ops->cond_sync_exp) {
1246 synctype[nsynctypes++] = RTWS_COND_GET_EXP;
1247 pr_info("%s: Testing conditional expedited GPs.\n", __func__);
1248 } else if (gp_cond_exp && (!cur_ops->get_gp_state_exp || !cur_ops->cond_sync_exp)) {
1249 pr_alert("%s: gp_cond_exp without primitives.\n", __func__);
1250 }
1251 if (gp_cond_full1 && cur_ops->get_gp_state && cur_ops->cond_sync_full) {
1252 synctype[nsynctypes++] = RTWS_COND_GET_FULL;
1253 pr_info("%s: Testing conditional full-state GPs.\n", __func__);
1254 } else if (gp_cond_full && (!cur_ops->get_gp_state || !cur_ops->cond_sync_full)) {
1255 pr_alert("%s: gp_cond_full without primitives.\n", __func__);
1256 }
1257 if (gp_cond_exp_full1 && cur_ops->get_gp_state_exp && cur_ops->cond_sync_exp_full) {
1258 synctype[nsynctypes++] = RTWS_COND_GET_EXP_FULL;
1259 pr_info("%s: Testing conditional full-state expedited GPs.\n", __func__);
1260 } else if (gp_cond_exp_full &&
1261 (!cur_ops->get_gp_state_exp || !cur_ops->cond_sync_exp_full)) {
1262 pr_alert("%s: gp_cond_exp_full without primitives.\n", __func__);
1263 }
1264 if (gp_exp1 && cur_ops->exp_sync) {
1265 synctype[nsynctypes++] = RTWS_EXP_SYNC;
1266 pr_info("%s: Testing expedited GPs.\n", __func__);
1267 } else if (gp_exp && !cur_ops->exp_sync) {
1268 pr_alert("%s: gp_exp without primitives.\n", __func__);
1269 }
1270 if (gp_normal1 && cur_ops->deferred_free) {
1271 synctype[nsynctypes++] = RTWS_DEF_FREE;
1272 pr_info("%s: Testing asynchronous GPs.\n", __func__);
1273 } else if (gp_normal && !cur_ops->deferred_free) {
1274 pr_alert("%s: gp_normal without primitives.\n", __func__);
1275 }
1276 if (gp_poll1 && cur_ops->get_comp_state && cur_ops->same_gp_state &&
1277 cur_ops->start_gp_poll && cur_ops->poll_gp_state) {
1278 synctype[nsynctypes++] = RTWS_POLL_GET;
1279 pr_info("%s: Testing polling GPs.\n", __func__);
1280 } else if (gp_poll && (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)) {
1281 pr_alert("%s: gp_poll without primitives.\n", __func__);
1282 }
1283 if (gp_poll_full1 && cur_ops->get_comp_state_full && cur_ops->same_gp_state_full
1284 && cur_ops->start_gp_poll_full && cur_ops->poll_gp_state_full) {
1285 synctype[nsynctypes++] = RTWS_POLL_GET_FULL;
1286 pr_info("%s: Testing polling full-state GPs.\n", __func__);
1287 } else if (gp_poll_full && (!cur_ops->start_gp_poll_full || !cur_ops->poll_gp_state_full)) {
1288 pr_alert("%s: gp_poll_full without primitives.\n", __func__);
1289 }
1290 if (gp_poll_exp1 && cur_ops->start_gp_poll_exp && cur_ops->poll_gp_state_exp) {
1291 synctype[nsynctypes++] = RTWS_POLL_GET_EXP;
1292 pr_info("%s: Testing polling expedited GPs.\n", __func__);
1293 } else if (gp_poll_exp && (!cur_ops->start_gp_poll_exp || !cur_ops->poll_gp_state_exp)) {
1294 pr_alert("%s: gp_poll_exp without primitives.\n", __func__);
1295 }
1296 if (gp_poll_exp_full1 && cur_ops->start_gp_poll_exp_full && cur_ops->poll_gp_state_full) {
1297 synctype[nsynctypes++] = RTWS_POLL_GET_EXP_FULL;
1298 pr_info("%s: Testing polling full-state expedited GPs.\n", __func__);
1299 } else if (gp_poll_exp_full &&
1300 (!cur_ops->start_gp_poll_exp_full || !cur_ops->poll_gp_state_full)) {
1301 pr_alert("%s: gp_poll_exp_full without primitives.\n", __func__);
1302 }
1303 if (gp_sync1 && cur_ops->sync) {
1304 synctype[nsynctypes++] = RTWS_SYNC;
1305 pr_info("%s: Testing normal GPs.\n", __func__);
1306 } else if (gp_sync && !cur_ops->sync) {
1307 pr_alert("%s: gp_sync without primitives.\n", __func__);
1308 }
1309}
1310
1311/*
1312 * Do the specified rcu_torture_writer() synchronous grace period,
1313 * while also testing out the polled APIs. Note well that the single-CPU
1314 * grace-period optimizations must be accounted for.
1315 */
1316static void do_rtws_sync(struct torture_random_state *trsp, void (*sync)(void))
1317{
1318 unsigned long cookie;
1319 struct rcu_gp_oldstate cookie_full;
1320 bool dopoll;
1321 bool dopoll_full;
1322 unsigned long r = torture_random(trsp);
1323
1324 dopoll = cur_ops->get_gp_state && cur_ops->poll_gp_state && !(r & 0x300);
1325 dopoll_full = cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full && !(r & 0xc00);
1326 if (dopoll || dopoll_full)
1327 cpus_read_lock();
1328 if (dopoll)
1329 cookie = cur_ops->get_gp_state();
1330 if (dopoll_full)
1331 cur_ops->get_gp_state_full(&cookie_full);
1332 if (cur_ops->poll_need_2gp && cur_ops->poll_need_2gp(dopoll, dopoll_full))
1333 sync();
1334 sync();
1335 WARN_ONCE(dopoll && !cur_ops->poll_gp_state(cookie),
1336 "%s: Cookie check 3 failed %pS() online %*pbl.",
1337 __func__, sync, cpumask_pr_args(cpu_online_mask));
1338 WARN_ONCE(dopoll_full && !cur_ops->poll_gp_state_full(&cookie_full),
1339 "%s: Cookie check 4 failed %pS() online %*pbl",
1340 __func__, sync, cpumask_pr_args(cpu_online_mask));
1341 if (dopoll || dopoll_full)
1342 cpus_read_unlock();
1343}
1344
1345/*
1346 * RCU torture writer kthread. Repeatedly substitutes a new structure
1347 * for that pointed to by rcu_torture_current, freeing the old structure
1348 * after a series of grace periods (the "pipeline").
1349 */
1350static int
1351rcu_torture_writer(void *arg)
1352{
1353 bool boot_ended;
1354 bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
1355 unsigned long cookie;
1356 struct rcu_gp_oldstate cookie_full;
1357 int expediting = 0;
1358 unsigned long gp_snap;
1359 unsigned long gp_snap1;
1360 struct rcu_gp_oldstate gp_snap_full;
1361 struct rcu_gp_oldstate gp_snap1_full;
1362 int i;
1363 int idx;
1364 int oldnice = task_nice(current);
1365 struct rcu_gp_oldstate rgo[NUM_ACTIVE_RCU_POLL_FULL_OLDSTATE];
1366 struct rcu_torture *rp;
1367 struct rcu_torture *old_rp;
1368 static DEFINE_TORTURE_RANDOM(rand);
1369 bool stutter_waited;
1370 unsigned long ulo[NUM_ACTIVE_RCU_POLL_OLDSTATE];
1371
1372 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
1373 if (!can_expedite)
1374 pr_alert("%s" TORTURE_FLAG
1375 " GP expediting controlled from boot/sysfs for %s.\n",
1376 torture_type, cur_ops->name);
1377 if (WARN_ONCE(nsynctypes == 0,
1378 "%s: No update-side primitives.\n", __func__)) {
1379 /*
1380 * No updates primitives, so don't try updating.
1381 * The resulting test won't be testing much, hence the
1382 * above WARN_ONCE().
1383 */
1384 rcu_torture_writer_state = RTWS_STOPPING;
1385 torture_kthread_stopping("rcu_torture_writer");
1386 return 0;
1387 }
1388
1389 do {
1390 rcu_torture_writer_state = RTWS_FIXED_DELAY;
1391 torture_hrtimeout_us(500, 1000, &rand);
1392 rp = rcu_torture_alloc();
1393 if (rp == NULL)
1394 continue;
1395 rp->rtort_pipe_count = 0;
1396 rcu_torture_writer_state = RTWS_DELAY;
1397 udelay(torture_random(&rand) & 0x3ff);
1398 rcu_torture_writer_state = RTWS_REPLACE;
1399 old_rp = rcu_dereference_check(rcu_torture_current,
1400 current == writer_task);
1401 rp->rtort_mbtest = 1;
1402 rcu_assign_pointer(rcu_torture_current, rp);
1403 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
1404 if (old_rp) {
1405 i = old_rp->rtort_pipe_count;
1406 if (i > RCU_TORTURE_PIPE_LEN)
1407 i = RCU_TORTURE_PIPE_LEN;
1408 atomic_inc(&rcu_torture_wcount[i]);
1409 WRITE_ONCE(old_rp->rtort_pipe_count,
1410 old_rp->rtort_pipe_count + 1);
1411
1412 // Make sure readers block polled grace periods.
1413 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) {
1414 idx = cur_ops->readlock();
1415 cookie = cur_ops->get_gp_state();
1416 WARN_ONCE(cur_ops->poll_gp_state(cookie),
1417 "%s: Cookie check 1 failed %s(%d) %lu->%lu\n",
1418 __func__,
1419 rcu_torture_writer_state_getname(),
1420 rcu_torture_writer_state,
1421 cookie, cur_ops->get_gp_state());
1422 if (cur_ops->get_gp_completed) {
1423 cookie = cur_ops->get_gp_completed();
1424 WARN_ON_ONCE(!cur_ops->poll_gp_state(cookie));
1425 }
1426 cur_ops->readunlock(idx);
1427 }
1428 if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full) {
1429 idx = cur_ops->readlock();
1430 cur_ops->get_gp_state_full(&cookie_full);
1431 WARN_ONCE(cur_ops->poll_gp_state_full(&cookie_full),
1432 "%s: Cookie check 5 failed %s(%d) online %*pbl\n",
1433 __func__,
1434 rcu_torture_writer_state_getname(),
1435 rcu_torture_writer_state,
1436 cpumask_pr_args(cpu_online_mask));
1437 if (cur_ops->get_gp_completed_full) {
1438 cur_ops->get_gp_completed_full(&cookie_full);
1439 WARN_ON_ONCE(!cur_ops->poll_gp_state_full(&cookie_full));
1440 }
1441 cur_ops->readunlock(idx);
1442 }
1443 switch (synctype[torture_random(&rand) % nsynctypes]) {
1444 case RTWS_DEF_FREE:
1445 rcu_torture_writer_state = RTWS_DEF_FREE;
1446 cur_ops->deferred_free(old_rp);
1447 break;
1448 case RTWS_EXP_SYNC:
1449 rcu_torture_writer_state = RTWS_EXP_SYNC;
1450 do_rtws_sync(&rand, cur_ops->exp_sync);
1451 rcu_torture_pipe_update(old_rp);
1452 break;
1453 case RTWS_COND_GET:
1454 rcu_torture_writer_state = RTWS_COND_GET;
1455 gp_snap = cur_ops->get_gp_state();
1456 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1457 rcu_torture_writer_state = RTWS_COND_SYNC;
1458 cur_ops->cond_sync(gp_snap);
1459 rcu_torture_pipe_update(old_rp);
1460 break;
1461 case RTWS_COND_GET_EXP:
1462 rcu_torture_writer_state = RTWS_COND_GET_EXP;
1463 gp_snap = cur_ops->get_gp_state_exp();
1464 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1465 rcu_torture_writer_state = RTWS_COND_SYNC_EXP;
1466 cur_ops->cond_sync_exp(gp_snap);
1467 rcu_torture_pipe_update(old_rp);
1468 break;
1469 case RTWS_COND_GET_FULL:
1470 rcu_torture_writer_state = RTWS_COND_GET_FULL;
1471 cur_ops->get_gp_state_full(&gp_snap_full);
1472 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1473 rcu_torture_writer_state = RTWS_COND_SYNC_FULL;
1474 cur_ops->cond_sync_full(&gp_snap_full);
1475 rcu_torture_pipe_update(old_rp);
1476 break;
1477 case RTWS_COND_GET_EXP_FULL:
1478 rcu_torture_writer_state = RTWS_COND_GET_EXP_FULL;
1479 cur_ops->get_gp_state_full(&gp_snap_full);
1480 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1481 rcu_torture_writer_state = RTWS_COND_SYNC_EXP_FULL;
1482 cur_ops->cond_sync_exp_full(&gp_snap_full);
1483 rcu_torture_pipe_update(old_rp);
1484 break;
1485 case RTWS_POLL_GET:
1486 rcu_torture_writer_state = RTWS_POLL_GET;
1487 for (i = 0; i < ARRAY_SIZE(ulo); i++)
1488 ulo[i] = cur_ops->get_comp_state();
1489 gp_snap = cur_ops->start_gp_poll();
1490 rcu_torture_writer_state = RTWS_POLL_WAIT;
1491 while (!cur_ops->poll_gp_state(gp_snap)) {
1492 gp_snap1 = cur_ops->get_gp_state();
1493 for (i = 0; i < ARRAY_SIZE(ulo); i++)
1494 if (cur_ops->poll_gp_state(ulo[i]) ||
1495 cur_ops->same_gp_state(ulo[i], gp_snap1)) {
1496 ulo[i] = gp_snap1;
1497 break;
1498 }
1499 WARN_ON_ONCE(i >= ARRAY_SIZE(ulo));
1500 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1501 &rand);
1502 }
1503 rcu_torture_pipe_update(old_rp);
1504 break;
1505 case RTWS_POLL_GET_FULL:
1506 rcu_torture_writer_state = RTWS_POLL_GET_FULL;
1507 for (i = 0; i < ARRAY_SIZE(rgo); i++)
1508 cur_ops->get_comp_state_full(&rgo[i]);
1509 cur_ops->start_gp_poll_full(&gp_snap_full);
1510 rcu_torture_writer_state = RTWS_POLL_WAIT_FULL;
1511 while (!cur_ops->poll_gp_state_full(&gp_snap_full)) {
1512 cur_ops->get_gp_state_full(&gp_snap1_full);
1513 for (i = 0; i < ARRAY_SIZE(rgo); i++)
1514 if (cur_ops->poll_gp_state_full(&rgo[i]) ||
1515 cur_ops->same_gp_state_full(&rgo[i],
1516 &gp_snap1_full)) {
1517 rgo[i] = gp_snap1_full;
1518 break;
1519 }
1520 WARN_ON_ONCE(i >= ARRAY_SIZE(rgo));
1521 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1522 &rand);
1523 }
1524 rcu_torture_pipe_update(old_rp);
1525 break;
1526 case RTWS_POLL_GET_EXP:
1527 rcu_torture_writer_state = RTWS_POLL_GET_EXP;
1528 gp_snap = cur_ops->start_gp_poll_exp();
1529 rcu_torture_writer_state = RTWS_POLL_WAIT_EXP;
1530 while (!cur_ops->poll_gp_state_exp(gp_snap))
1531 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1532 &rand);
1533 rcu_torture_pipe_update(old_rp);
1534 break;
1535 case RTWS_POLL_GET_EXP_FULL:
1536 rcu_torture_writer_state = RTWS_POLL_GET_EXP_FULL;
1537 cur_ops->start_gp_poll_exp_full(&gp_snap_full);
1538 rcu_torture_writer_state = RTWS_POLL_WAIT_EXP_FULL;
1539 while (!cur_ops->poll_gp_state_full(&gp_snap_full))
1540 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1541 &rand);
1542 rcu_torture_pipe_update(old_rp);
1543 break;
1544 case RTWS_SYNC:
1545 rcu_torture_writer_state = RTWS_SYNC;
1546 do_rtws_sync(&rand, cur_ops->sync);
1547 rcu_torture_pipe_update(old_rp);
1548 break;
1549 default:
1550 WARN_ON_ONCE(1);
1551 break;
1552 }
1553 }
1554 WRITE_ONCE(rcu_torture_current_version,
1555 rcu_torture_current_version + 1);
1556 /* Cycle through nesting levels of rcu_expedite_gp() calls. */
1557 if (can_expedite &&
1558 !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
1559 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
1560 if (expediting >= 0)
1561 rcu_expedite_gp();
1562 else
1563 rcu_unexpedite_gp();
1564 if (++expediting > 3)
1565 expediting = -expediting;
1566 } else if (!can_expedite) { /* Disabled during boot, recheck. */
1567 can_expedite = !rcu_gp_is_expedited() &&
1568 !rcu_gp_is_normal();
1569 }
1570 rcu_torture_writer_state = RTWS_STUTTER;
1571 boot_ended = rcu_inkernel_boot_has_ended();
1572 stutter_waited = stutter_wait("rcu_torture_writer");
1573 if (stutter_waited &&
1574 !atomic_read(&rcu_fwd_cb_nodelay) &&
1575 !cur_ops->slow_gps &&
1576 !torture_must_stop() &&
1577 boot_ended)
1578 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++)
1579 if (list_empty(&rcu_tortures[i].rtort_free) &&
1580 rcu_access_pointer(rcu_torture_current) !=
1581 &rcu_tortures[i]) {
1582 tracing_off();
1583 WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count);
1584 rcu_ftrace_dump(DUMP_ALL);
1585 }
1586 if (stutter_waited)
1587 sched_set_normal(current, oldnice);
1588 } while (!torture_must_stop());
1589 rcu_torture_current = NULL; // Let stats task know that we are done.
1590 /* Reset expediting back to unexpedited. */
1591 if (expediting > 0)
1592 expediting = -expediting;
1593 while (can_expedite && expediting++ < 0)
1594 rcu_unexpedite_gp();
1595 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
1596 if (!can_expedite)
1597 pr_alert("%s" TORTURE_FLAG
1598 " Dynamic grace-period expediting was disabled.\n",
1599 torture_type);
1600 rcu_torture_writer_state = RTWS_STOPPING;
1601 torture_kthread_stopping("rcu_torture_writer");
1602 return 0;
1603}
1604
1605/*
1606 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
1607 * delay between calls.
1608 */
1609static int
1610rcu_torture_fakewriter(void *arg)
1611{
1612 unsigned long gp_snap;
1613 struct rcu_gp_oldstate gp_snap_full;
1614 DEFINE_TORTURE_RANDOM(rand);
1615
1616 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1617 set_user_nice(current, MAX_NICE);
1618
1619 if (WARN_ONCE(nsynctypes == 0,
1620 "%s: No update-side primitives.\n", __func__)) {
1621 /*
1622 * No updates primitives, so don't try updating.
1623 * The resulting test won't be testing much, hence the
1624 * above WARN_ONCE().
1625 */
1626 torture_kthread_stopping("rcu_torture_fakewriter");
1627 return 0;
1628 }
1629
1630 do {
1631 torture_hrtimeout_jiffies(torture_random(&rand) % 10, &rand);
1632 if (cur_ops->cb_barrier != NULL &&
1633 torture_random(&rand) % (nfakewriters * 8) == 0) {
1634 cur_ops->cb_barrier();
1635 } else {
1636 switch (synctype[torture_random(&rand) % nsynctypes]) {
1637 case RTWS_DEF_FREE:
1638 break;
1639 case RTWS_EXP_SYNC:
1640 cur_ops->exp_sync();
1641 break;
1642 case RTWS_COND_GET:
1643 gp_snap = cur_ops->get_gp_state();
1644 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1645 cur_ops->cond_sync(gp_snap);
1646 break;
1647 case RTWS_COND_GET_EXP:
1648 gp_snap = cur_ops->get_gp_state_exp();
1649 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1650 cur_ops->cond_sync_exp(gp_snap);
1651 break;
1652 case RTWS_COND_GET_FULL:
1653 cur_ops->get_gp_state_full(&gp_snap_full);
1654 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1655 cur_ops->cond_sync_full(&gp_snap_full);
1656 break;
1657 case RTWS_COND_GET_EXP_FULL:
1658 cur_ops->get_gp_state_full(&gp_snap_full);
1659 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1660 cur_ops->cond_sync_exp_full(&gp_snap_full);
1661 break;
1662 case RTWS_POLL_GET:
1663 gp_snap = cur_ops->start_gp_poll();
1664 while (!cur_ops->poll_gp_state(gp_snap)) {
1665 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1666 &rand);
1667 }
1668 break;
1669 case RTWS_POLL_GET_FULL:
1670 cur_ops->start_gp_poll_full(&gp_snap_full);
1671 while (!cur_ops->poll_gp_state_full(&gp_snap_full)) {
1672 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1673 &rand);
1674 }
1675 break;
1676 case RTWS_POLL_GET_EXP:
1677 gp_snap = cur_ops->start_gp_poll_exp();
1678 while (!cur_ops->poll_gp_state_exp(gp_snap)) {
1679 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1680 &rand);
1681 }
1682 break;
1683 case RTWS_POLL_GET_EXP_FULL:
1684 cur_ops->start_gp_poll_exp_full(&gp_snap_full);
1685 while (!cur_ops->poll_gp_state_full(&gp_snap_full)) {
1686 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1687 &rand);
1688 }
1689 break;
1690 case RTWS_SYNC:
1691 cur_ops->sync();
1692 break;
1693 default:
1694 WARN_ON_ONCE(1);
1695 break;
1696 }
1697 }
1698 stutter_wait("rcu_torture_fakewriter");
1699 } while (!torture_must_stop());
1700
1701 torture_kthread_stopping("rcu_torture_fakewriter");
1702 return 0;
1703}
1704
1705static void rcu_torture_timer_cb(struct rcu_head *rhp)
1706{
1707 kfree(rhp);
1708}
1709
1710// Set up and carry out testing of RCU's global memory ordering
1711static void rcu_torture_reader_do_mbchk(long myid, struct rcu_torture *rtp,
1712 struct torture_random_state *trsp)
1713{
1714 unsigned long loops;
1715 int noc = torture_num_online_cpus();
1716 int rdrchked;
1717 int rdrchker;
1718 struct rcu_torture_reader_check *rtrcp; // Me.
1719 struct rcu_torture_reader_check *rtrcp_assigner; // Assigned us to do checking.
1720 struct rcu_torture_reader_check *rtrcp_chked; // Reader being checked.
1721 struct rcu_torture_reader_check *rtrcp_chker; // Reader doing checking when not me.
1722
1723 if (myid < 0)
1724 return; // Don't try this from timer handlers.
1725
1726 // Increment my counter.
1727 rtrcp = &rcu_torture_reader_mbchk[myid];
1728 WRITE_ONCE(rtrcp->rtc_myloops, rtrcp->rtc_myloops + 1);
1729
1730 // Attempt to assign someone else some checking work.
1731 rdrchked = torture_random(trsp) % nrealreaders;
1732 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked];
1733 rdrchker = torture_random(trsp) % nrealreaders;
1734 rtrcp_chker = &rcu_torture_reader_mbchk[rdrchker];
1735 if (rdrchked != myid && rdrchked != rdrchker && noc >= rdrchked && noc >= rdrchker &&
1736 smp_load_acquire(&rtrcp->rtc_chkrdr) < 0 && // Pairs with smp_store_release below.
1737 !READ_ONCE(rtp->rtort_chkp) &&
1738 !smp_load_acquire(&rtrcp_chker->rtc_assigner)) { // Pairs with smp_store_release below.
1739 rtrcp->rtc_chkloops = READ_ONCE(rtrcp_chked->rtc_myloops);
1740 WARN_ON_ONCE(rtrcp->rtc_chkrdr >= 0);
1741 rtrcp->rtc_chkrdr = rdrchked;
1742 WARN_ON_ONCE(rtrcp->rtc_ready); // This gets set after the grace period ends.
1743 if (cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, NULL, rtrcp) ||
1744 cmpxchg_relaxed(&rtp->rtort_chkp, NULL, rtrcp))
1745 (void)cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, rtrcp, NULL); // Back out.
1746 }
1747
1748 // If assigned some completed work, do it!
1749 rtrcp_assigner = READ_ONCE(rtrcp->rtc_assigner);
1750 if (!rtrcp_assigner || !smp_load_acquire(&rtrcp_assigner->rtc_ready))
1751 return; // No work or work not yet ready.
1752 rdrchked = rtrcp_assigner->rtc_chkrdr;
1753 if (WARN_ON_ONCE(rdrchked < 0))
1754 return;
1755 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked];
1756 loops = READ_ONCE(rtrcp_chked->rtc_myloops);
1757 atomic_inc(&n_rcu_torture_mbchk_tries);
1758 if (ULONG_CMP_LT(loops, rtrcp_assigner->rtc_chkloops))
1759 atomic_inc(&n_rcu_torture_mbchk_fail);
1760 rtrcp_assigner->rtc_chkloops = loops + ULONG_MAX / 2;
1761 rtrcp_assigner->rtc_ready = 0;
1762 smp_store_release(&rtrcp->rtc_assigner, NULL); // Someone else can assign us work.
1763 smp_store_release(&rtrcp_assigner->rtc_chkrdr, -1); // Assigner can again assign.
1764}
1765
1766/*
1767 * Do one extension of an RCU read-side critical section using the
1768 * current reader state in readstate (set to zero for initial entry
1769 * to extended critical section), set the new state as specified by
1770 * newstate (set to zero for final exit from extended critical section),
1771 * and random-number-generator state in trsp. If this is neither the
1772 * beginning or end of the critical section and if there was actually a
1773 * change, do a ->read_delay().
1774 */
1775static void rcutorture_one_extend(int *readstate, int newstate,
1776 struct torture_random_state *trsp,
1777 struct rt_read_seg *rtrsp)
1778{
1779 unsigned long flags;
1780 int idxnew1 = -1;
1781 int idxnew2 = -1;
1782 int idxold1 = *readstate;
1783 int idxold2 = idxold1;
1784 int statesnew = ~*readstate & newstate;
1785 int statesold = *readstate & ~newstate;
1786
1787 WARN_ON_ONCE(idxold2 < 0);
1788 WARN_ON_ONCE((idxold2 >> RCUTORTURE_RDR_SHIFT_2) > 1);
1789 rtrsp->rt_readstate = newstate;
1790
1791 /* First, put new protection in place to avoid critical-section gap. */
1792 if (statesnew & RCUTORTURE_RDR_BH)
1793 local_bh_disable();
1794 if (statesnew & RCUTORTURE_RDR_RBH)
1795 rcu_read_lock_bh();
1796 if (statesnew & RCUTORTURE_RDR_IRQ)
1797 local_irq_disable();
1798 if (statesnew & RCUTORTURE_RDR_PREEMPT)
1799 preempt_disable();
1800 if (statesnew & RCUTORTURE_RDR_SCHED)
1801 rcu_read_lock_sched();
1802 if (statesnew & RCUTORTURE_RDR_RCU_1)
1803 idxnew1 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_1;
1804 if (statesnew & RCUTORTURE_RDR_RCU_2)
1805 idxnew2 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_2;
1806
1807 /*
1808 * Next, remove old protection, in decreasing order of strength
1809 * to avoid unlock paths that aren't safe in the stronger
1810 * context. Namely: BH can not be enabled with disabled interrupts.
1811 * Additionally PREEMPT_RT requires that BH is enabled in preemptible
1812 * context.
1813 */
1814 if (statesold & RCUTORTURE_RDR_IRQ)
1815 local_irq_enable();
1816 if (statesold & RCUTORTURE_RDR_PREEMPT)
1817 preempt_enable();
1818 if (statesold & RCUTORTURE_RDR_SCHED)
1819 rcu_read_unlock_sched();
1820 if (statesold & RCUTORTURE_RDR_BH)
1821 local_bh_enable();
1822 if (statesold & RCUTORTURE_RDR_RBH)
1823 rcu_read_unlock_bh();
1824 if (statesold & RCUTORTURE_RDR_RCU_2) {
1825 cur_ops->readunlock((idxold2 >> RCUTORTURE_RDR_SHIFT_2) & 0x1);
1826 WARN_ON_ONCE(idxnew2 != -1);
1827 idxold2 = 0;
1828 }
1829 if (statesold & RCUTORTURE_RDR_RCU_1) {
1830 bool lockit;
1831
1832 lockit = !cur_ops->no_pi_lock && !statesnew && !(torture_random(trsp) & 0xffff);
1833 if (lockit)
1834 raw_spin_lock_irqsave(¤t->pi_lock, flags);
1835 cur_ops->readunlock((idxold1 >> RCUTORTURE_RDR_SHIFT_1) & 0x1);
1836 WARN_ON_ONCE(idxnew1 != -1);
1837 idxold1 = 0;
1838 if (lockit)
1839 raw_spin_unlock_irqrestore(¤t->pi_lock, flags);
1840 }
1841
1842 /* Delay if neither beginning nor end and there was a change. */
1843 if ((statesnew || statesold) && *readstate && newstate)
1844 cur_ops->read_delay(trsp, rtrsp);
1845
1846 /* Update the reader state. */
1847 if (idxnew1 == -1)
1848 idxnew1 = idxold1 & RCUTORTURE_RDR_MASK_1;
1849 WARN_ON_ONCE(idxnew1 < 0);
1850 if (WARN_ON_ONCE((idxnew1 >> RCUTORTURE_RDR_SHIFT_1) > 1))
1851 pr_info("Unexpected idxnew1 value of %#x\n", idxnew1);
1852 if (idxnew2 == -1)
1853 idxnew2 = idxold2 & RCUTORTURE_RDR_MASK_2;
1854 WARN_ON_ONCE(idxnew2 < 0);
1855 WARN_ON_ONCE((idxnew2 >> RCUTORTURE_RDR_SHIFT_2) > 1);
1856 *readstate = idxnew1 | idxnew2 | newstate;
1857 WARN_ON_ONCE(*readstate < 0);
1858 if (WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT_2) > 1))
1859 pr_info("Unexpected idxnew2 value of %#x\n", idxnew2);
1860}
1861
1862/* Return the biggest extendables mask given current RCU and boot parameters. */
1863static int rcutorture_extend_mask_max(void)
1864{
1865 int mask;
1866
1867 WARN_ON_ONCE(extendables & ~RCUTORTURE_MAX_EXTEND);
1868 mask = extendables & RCUTORTURE_MAX_EXTEND & cur_ops->extendables;
1869 mask = mask | RCUTORTURE_RDR_RCU_1 | RCUTORTURE_RDR_RCU_2;
1870 return mask;
1871}
1872
1873/* Return a random protection state mask, but with at least one bit set. */
1874static int
1875rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp)
1876{
1877 int mask = rcutorture_extend_mask_max();
1878 unsigned long randmask1 = torture_random(trsp) >> 8;
1879 unsigned long randmask2 = randmask1 >> 3;
1880 unsigned long preempts = RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED;
1881 unsigned long preempts_irq = preempts | RCUTORTURE_RDR_IRQ;
1882 unsigned long bhs = RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH;
1883
1884 WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT_1);
1885 /* Mostly only one bit (need preemption!), sometimes lots of bits. */
1886 if (!(randmask1 & 0x7))
1887 mask = mask & randmask2;
1888 else
1889 mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS));
1890
1891 // Can't have nested RCU reader without outer RCU reader.
1892 if (!(mask & RCUTORTURE_RDR_RCU_1) && (mask & RCUTORTURE_RDR_RCU_2)) {
1893 if (oldmask & RCUTORTURE_RDR_RCU_1)
1894 mask &= ~RCUTORTURE_RDR_RCU_2;
1895 else
1896 mask |= RCUTORTURE_RDR_RCU_1;
1897 }
1898
1899 /*
1900 * Can't enable bh w/irq disabled.
1901 */
1902 if (mask & RCUTORTURE_RDR_IRQ)
1903 mask |= oldmask & bhs;
1904
1905 /*
1906 * Ideally these sequences would be detected in debug builds
1907 * (regardless of RT), but until then don't stop testing
1908 * them on non-RT.
1909 */
1910 if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
1911 /* Can't modify BH in atomic context */
1912 if (oldmask & preempts_irq)
1913 mask &= ~bhs;
1914 if ((oldmask | mask) & preempts_irq)
1915 mask |= oldmask & bhs;
1916 }
1917
1918 return mask ?: RCUTORTURE_RDR_RCU_1;
1919}
1920
1921/*
1922 * Do a randomly selected number of extensions of an existing RCU read-side
1923 * critical section.
1924 */
1925static struct rt_read_seg *
1926rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp,
1927 struct rt_read_seg *rtrsp)
1928{
1929 int i;
1930 int j;
1931 int mask = rcutorture_extend_mask_max();
1932
1933 WARN_ON_ONCE(!*readstate); /* -Existing- RCU read-side critsect! */
1934 if (!((mask - 1) & mask))
1935 return rtrsp; /* Current RCU reader not extendable. */
1936 /* Bias towards larger numbers of loops. */
1937 i = (torture_random(trsp) >> 3);
1938 i = ((i | (i >> 3)) & RCUTORTURE_RDR_MAX_LOOPS) + 1;
1939 for (j = 0; j < i; j++) {
1940 mask = rcutorture_extend_mask(*readstate, trsp);
1941 rcutorture_one_extend(readstate, mask, trsp, &rtrsp[j]);
1942 }
1943 return &rtrsp[j];
1944}
1945
1946/*
1947 * Do one read-side critical section, returning false if there was
1948 * no data to read. Can be invoked both from process context and
1949 * from a timer handler.
1950 */
1951static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid)
1952{
1953 bool checkpolling = !(torture_random(trsp) & 0xfff);
1954 unsigned long cookie;
1955 struct rcu_gp_oldstate cookie_full;
1956 int i;
1957 unsigned long started;
1958 unsigned long completed;
1959 int newstate;
1960 struct rcu_torture *p;
1961 int pipe_count;
1962 int readstate = 0;
1963 struct rt_read_seg rtseg[RCUTORTURE_RDR_MAX_SEGS] = { { 0 } };
1964 struct rt_read_seg *rtrsp = &rtseg[0];
1965 struct rt_read_seg *rtrsp1;
1966 unsigned long long ts;
1967
1968 WARN_ON_ONCE(!rcu_is_watching());
1969 newstate = rcutorture_extend_mask(readstate, trsp);
1970 rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++);
1971 if (checkpolling) {
1972 if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
1973 cookie = cur_ops->get_gp_state();
1974 if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full)
1975 cur_ops->get_gp_state_full(&cookie_full);
1976 }
1977 started = cur_ops->get_gp_seq();
1978 ts = rcu_trace_clock_local();
1979 p = rcu_dereference_check(rcu_torture_current,
1980 !cur_ops->readlock_held || cur_ops->readlock_held());
1981 if (p == NULL) {
1982 /* Wait for rcu_torture_writer to get underway */
1983 rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
1984 return false;
1985 }
1986 if (p->rtort_mbtest == 0)
1987 atomic_inc(&n_rcu_torture_mberror);
1988 rcu_torture_reader_do_mbchk(myid, p, trsp);
1989 rtrsp = rcutorture_loop_extend(&readstate, trsp, rtrsp);
1990 preempt_disable();
1991 pipe_count = READ_ONCE(p->rtort_pipe_count);
1992 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1993 /* Should not happen, but... */
1994 pipe_count = RCU_TORTURE_PIPE_LEN;
1995 }
1996 completed = cur_ops->get_gp_seq();
1997 if (pipe_count > 1) {
1998 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
1999 ts, started, completed);
2000 rcu_ftrace_dump(DUMP_ALL);
2001 }
2002 __this_cpu_inc(rcu_torture_count[pipe_count]);
2003 completed = rcutorture_seq_diff(completed, started);
2004 if (completed > RCU_TORTURE_PIPE_LEN) {
2005 /* Should not happen, but... */
2006 completed = RCU_TORTURE_PIPE_LEN;
2007 }
2008 __this_cpu_inc(rcu_torture_batch[completed]);
2009 preempt_enable();
2010 if (checkpolling) {
2011 if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
2012 WARN_ONCE(cur_ops->poll_gp_state(cookie),
2013 "%s: Cookie check 2 failed %s(%d) %lu->%lu\n",
2014 __func__,
2015 rcu_torture_writer_state_getname(),
2016 rcu_torture_writer_state,
2017 cookie, cur_ops->get_gp_state());
2018 if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full)
2019 WARN_ONCE(cur_ops->poll_gp_state_full(&cookie_full),
2020 "%s: Cookie check 6 failed %s(%d) online %*pbl\n",
2021 __func__,
2022 rcu_torture_writer_state_getname(),
2023 rcu_torture_writer_state,
2024 cpumask_pr_args(cpu_online_mask));
2025 }
2026 rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
2027 WARN_ON_ONCE(readstate);
2028 // This next splat is expected behavior if leakpointer, especially
2029 // for CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels.
2030 WARN_ON_ONCE(leakpointer && READ_ONCE(p->rtort_pipe_count) > 1);
2031
2032 /* If error or close call, record the sequence of reader protections. */
2033 if ((pipe_count > 1 || completed > 1) && !xchg(&err_segs_recorded, 1)) {
2034 i = 0;
2035 for (rtrsp1 = &rtseg[0]; rtrsp1 < rtrsp; rtrsp1++)
2036 err_segs[i++] = *rtrsp1;
2037 rt_read_nsegs = i;
2038 }
2039
2040 return true;
2041}
2042
2043static DEFINE_TORTURE_RANDOM_PERCPU(rcu_torture_timer_rand);
2044
2045/*
2046 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
2047 * incrementing the corresponding element of the pipeline array. The
2048 * counter in the element should never be greater than 1, otherwise, the
2049 * RCU implementation is broken.
2050 */
2051static void rcu_torture_timer(struct timer_list *unused)
2052{
2053 atomic_long_inc(&n_rcu_torture_timers);
2054 (void)rcu_torture_one_read(this_cpu_ptr(&rcu_torture_timer_rand), -1);
2055
2056 /* Test call_rcu() invocation from interrupt handler. */
2057 if (cur_ops->call) {
2058 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT);
2059
2060 if (rhp)
2061 cur_ops->call(rhp, rcu_torture_timer_cb);
2062 }
2063}
2064
2065/*
2066 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
2067 * incrementing the corresponding element of the pipeline array. The
2068 * counter in the element should never be greater than 1, otherwise, the
2069 * RCU implementation is broken.
2070 */
2071static int
2072rcu_torture_reader(void *arg)
2073{
2074 unsigned long lastsleep = jiffies;
2075 long myid = (long)arg;
2076 int mynumonline = myid;
2077 DEFINE_TORTURE_RANDOM(rand);
2078 struct timer_list t;
2079
2080 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
2081 set_user_nice(current, MAX_NICE);
2082 if (irqreader && cur_ops->irq_capable)
2083 timer_setup_on_stack(&t, rcu_torture_timer, 0);
2084 tick_dep_set_task(current, TICK_DEP_BIT_RCU);
2085 do {
2086 if (irqreader && cur_ops->irq_capable) {
2087 if (!timer_pending(&t))
2088 mod_timer(&t, jiffies + 1);
2089 }
2090 if (!rcu_torture_one_read(&rand, myid) && !torture_must_stop())
2091 schedule_timeout_interruptible(HZ);
2092 if (time_after(jiffies, lastsleep) && !torture_must_stop()) {
2093 torture_hrtimeout_us(500, 1000, &rand);
2094 lastsleep = jiffies + 10;
2095 }
2096 while (torture_num_online_cpus() < mynumonline && !torture_must_stop())
2097 schedule_timeout_interruptible(HZ / 5);
2098 stutter_wait("rcu_torture_reader");
2099 } while (!torture_must_stop());
2100 if (irqreader && cur_ops->irq_capable) {
2101 del_timer_sync(&t);
2102 destroy_timer_on_stack(&t);
2103 }
2104 tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
2105 torture_kthread_stopping("rcu_torture_reader");
2106 return 0;
2107}
2108
2109/*
2110 * Randomly Toggle CPUs' callback-offload state. This uses hrtimers to
2111 * increase race probabilities and fuzzes the interval between toggling.
2112 */
2113static int rcu_nocb_toggle(void *arg)
2114{
2115 int cpu;
2116 int maxcpu = -1;
2117 int oldnice = task_nice(current);
2118 long r;
2119 DEFINE_TORTURE_RANDOM(rand);
2120 ktime_t toggle_delay;
2121 unsigned long toggle_fuzz;
2122 ktime_t toggle_interval = ms_to_ktime(nocbs_toggle);
2123
2124 VERBOSE_TOROUT_STRING("rcu_nocb_toggle task started");
2125 while (!rcu_inkernel_boot_has_ended())
2126 schedule_timeout_interruptible(HZ / 10);
2127 for_each_online_cpu(cpu)
2128 maxcpu = cpu;
2129 WARN_ON(maxcpu < 0);
2130 if (toggle_interval > ULONG_MAX)
2131 toggle_fuzz = ULONG_MAX >> 3;
2132 else
2133 toggle_fuzz = toggle_interval >> 3;
2134 if (toggle_fuzz <= 0)
2135 toggle_fuzz = NSEC_PER_USEC;
2136 do {
2137 r = torture_random(&rand);
2138 cpu = (r >> 4) % (maxcpu + 1);
2139 if (r & 0x1) {
2140 rcu_nocb_cpu_offload(cpu);
2141 atomic_long_inc(&n_nocb_offload);
2142 } else {
2143 rcu_nocb_cpu_deoffload(cpu);
2144 atomic_long_inc(&n_nocb_deoffload);
2145 }
2146 toggle_delay = torture_random(&rand) % toggle_fuzz + toggle_interval;
2147 set_current_state(TASK_INTERRUPTIBLE);
2148 schedule_hrtimeout(&toggle_delay, HRTIMER_MODE_REL);
2149 if (stutter_wait("rcu_nocb_toggle"))
2150 sched_set_normal(current, oldnice);
2151 } while (!torture_must_stop());
2152 torture_kthread_stopping("rcu_nocb_toggle");
2153 return 0;
2154}
2155
2156/*
2157 * Print torture statistics. Caller must ensure that there is only
2158 * one call to this function at a given time!!! This is normally
2159 * accomplished by relying on the module system to only have one copy
2160 * of the module loaded, and then by giving the rcu_torture_stats
2161 * kthread full control (or the init/cleanup functions when rcu_torture_stats
2162 * thread is not running).
2163 */
2164static void
2165rcu_torture_stats_print(void)
2166{
2167 int cpu;
2168 int i;
2169 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
2170 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
2171 struct rcu_torture *rtcp;
2172 static unsigned long rtcv_snap = ULONG_MAX;
2173 static bool splatted;
2174 struct task_struct *wtp;
2175
2176 for_each_possible_cpu(cpu) {
2177 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
2178 pipesummary[i] += READ_ONCE(per_cpu(rcu_torture_count, cpu)[i]);
2179 batchsummary[i] += READ_ONCE(per_cpu(rcu_torture_batch, cpu)[i]);
2180 }
2181 }
2182 for (i = RCU_TORTURE_PIPE_LEN; i >= 0; i--) {
2183 if (pipesummary[i] != 0)
2184 break;
2185 }
2186
2187 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2188 rtcp = rcu_access_pointer(rcu_torture_current);
2189 pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
2190 rtcp,
2191 rtcp && !rcu_stall_is_suppressed_at_boot() ? "ver" : "VER",
2192 rcu_torture_current_version,
2193 list_empty(&rcu_torture_freelist),
2194 atomic_read(&n_rcu_torture_alloc),
2195 atomic_read(&n_rcu_torture_alloc_fail),
2196 atomic_read(&n_rcu_torture_free));
2197 pr_cont("rtmbe: %d rtmbkf: %d/%d rtbe: %ld rtbke: %ld rtbre: %ld ",
2198 atomic_read(&n_rcu_torture_mberror),
2199 atomic_read(&n_rcu_torture_mbchk_fail), atomic_read(&n_rcu_torture_mbchk_tries),
2200 n_rcu_torture_barrier_error,
2201 n_rcu_torture_boost_ktrerror,
2202 n_rcu_torture_boost_rterror);
2203 pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
2204 n_rcu_torture_boost_failure,
2205 n_rcu_torture_boosts,
2206 atomic_long_read(&n_rcu_torture_timers));
2207 torture_onoff_stats();
2208 pr_cont("barrier: %ld/%ld:%ld ",
2209 data_race(n_barrier_successes),
2210 data_race(n_barrier_attempts),
2211 data_race(n_rcu_torture_barrier_error));
2212 pr_cont("read-exits: %ld ", data_race(n_read_exits)); // Statistic.
2213 pr_cont("nocb-toggles: %ld:%ld\n",
2214 atomic_long_read(&n_nocb_offload), atomic_long_read(&n_nocb_deoffload));
2215
2216 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2217 if (atomic_read(&n_rcu_torture_mberror) ||
2218 atomic_read(&n_rcu_torture_mbchk_fail) ||
2219 n_rcu_torture_barrier_error || n_rcu_torture_boost_ktrerror ||
2220 n_rcu_torture_boost_rterror || n_rcu_torture_boost_failure ||
2221 i > 1) {
2222 pr_cont("%s", "!!! ");
2223 atomic_inc(&n_rcu_torture_error);
2224 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mberror));
2225 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mbchk_fail));
2226 WARN_ON_ONCE(n_rcu_torture_barrier_error); // rcu_barrier()
2227 WARN_ON_ONCE(n_rcu_torture_boost_ktrerror); // no boost kthread
2228 WARN_ON_ONCE(n_rcu_torture_boost_rterror); // can't set RT prio
2229 WARN_ON_ONCE(n_rcu_torture_boost_failure); // boost failed (TIMER_SOFTIRQ RT prio?)
2230 WARN_ON_ONCE(i > 1); // Too-short grace period
2231 }
2232 pr_cont("Reader Pipe: ");
2233 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
2234 pr_cont(" %ld", pipesummary[i]);
2235 pr_cont("\n");
2236
2237 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2238 pr_cont("Reader Batch: ");
2239 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
2240 pr_cont(" %ld", batchsummary[i]);
2241 pr_cont("\n");
2242
2243 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2244 pr_cont("Free-Block Circulation: ");
2245 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
2246 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
2247 }
2248 pr_cont("\n");
2249
2250 if (cur_ops->stats)
2251 cur_ops->stats();
2252 if (rtcv_snap == rcu_torture_current_version &&
2253 rcu_access_pointer(rcu_torture_current) &&
2254 !rcu_stall_is_suppressed()) {
2255 int __maybe_unused flags = 0;
2256 unsigned long __maybe_unused gp_seq = 0;
2257
2258 rcutorture_get_gp_data(cur_ops->ttype,
2259 &flags, &gp_seq);
2260 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp,
2261 &flags, &gp_seq);
2262 wtp = READ_ONCE(writer_task);
2263 pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#x cpu %d\n",
2264 rcu_torture_writer_state_getname(),
2265 rcu_torture_writer_state, gp_seq, flags,
2266 wtp == NULL ? ~0U : wtp->__state,
2267 wtp == NULL ? -1 : (int)task_cpu(wtp));
2268 if (!splatted && wtp) {
2269 sched_show_task(wtp);
2270 splatted = true;
2271 }
2272 if (cur_ops->gp_kthread_dbg)
2273 cur_ops->gp_kthread_dbg();
2274 rcu_ftrace_dump(DUMP_ALL);
2275 }
2276 rtcv_snap = rcu_torture_current_version;
2277}
2278
2279/*
2280 * Periodically prints torture statistics, if periodic statistics printing
2281 * was specified via the stat_interval module parameter.
2282 */
2283static int
2284rcu_torture_stats(void *arg)
2285{
2286 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
2287 do {
2288 schedule_timeout_interruptible(stat_interval * HZ);
2289 rcu_torture_stats_print();
2290 torture_shutdown_absorb("rcu_torture_stats");
2291 } while (!torture_must_stop());
2292 torture_kthread_stopping("rcu_torture_stats");
2293 return 0;
2294}
2295
2296/* Test mem_dump_obj() and friends. */
2297static void rcu_torture_mem_dump_obj(void)
2298{
2299 struct rcu_head *rhp;
2300 struct kmem_cache *kcp;
2301 static int z;
2302
2303 kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL);
2304 if (WARN_ON_ONCE(!kcp))
2305 return;
2306 rhp = kmem_cache_alloc(kcp, GFP_KERNEL);
2307 if (WARN_ON_ONCE(!rhp)) {
2308 kmem_cache_destroy(kcp);
2309 return;
2310 }
2311 pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z);
2312 pr_alert("mem_dump_obj(ZERO_SIZE_PTR):");
2313 mem_dump_obj(ZERO_SIZE_PTR);
2314 pr_alert("mem_dump_obj(NULL):");
2315 mem_dump_obj(NULL);
2316 pr_alert("mem_dump_obj(%px):", &rhp);
2317 mem_dump_obj(&rhp);
2318 pr_alert("mem_dump_obj(%px):", rhp);
2319 mem_dump_obj(rhp);
2320 pr_alert("mem_dump_obj(%px):", &rhp->func);
2321 mem_dump_obj(&rhp->func);
2322 pr_alert("mem_dump_obj(%px):", &z);
2323 mem_dump_obj(&z);
2324 kmem_cache_free(kcp, rhp);
2325 kmem_cache_destroy(kcp);
2326 rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
2327 if (WARN_ON_ONCE(!rhp))
2328 return;
2329 pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
2330 pr_alert("mem_dump_obj(kmalloc %px):", rhp);
2331 mem_dump_obj(rhp);
2332 pr_alert("mem_dump_obj(kmalloc %px):", &rhp->func);
2333 mem_dump_obj(&rhp->func);
2334 kfree(rhp);
2335 rhp = vmalloc(4096);
2336 if (WARN_ON_ONCE(!rhp))
2337 return;
2338 pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
2339 pr_alert("mem_dump_obj(vmalloc %px):", rhp);
2340 mem_dump_obj(rhp);
2341 pr_alert("mem_dump_obj(vmalloc %px):", &rhp->func);
2342 mem_dump_obj(&rhp->func);
2343 vfree(rhp);
2344}
2345
2346static void
2347rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
2348{
2349 pr_alert("%s" TORTURE_FLAG
2350 "--- %s: nreaders=%d nfakewriters=%d "
2351 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
2352 "shuffle_interval=%d stutter=%d irqreader=%d "
2353 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
2354 "test_boost=%d/%d test_boost_interval=%d "
2355 "test_boost_duration=%d shutdown_secs=%d "
2356 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d "
2357 "stall_cpu_block=%d "
2358 "n_barrier_cbs=%d "
2359 "onoff_interval=%d onoff_holdoff=%d "
2360 "read_exit_delay=%d read_exit_burst=%d "
2361 "nocbs_nthreads=%d nocbs_toggle=%d\n",
2362 torture_type, tag, nrealreaders, nfakewriters,
2363 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
2364 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
2365 test_boost, cur_ops->can_boost,
2366 test_boost_interval, test_boost_duration, shutdown_secs,
2367 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff,
2368 stall_cpu_block,
2369 n_barrier_cbs,
2370 onoff_interval, onoff_holdoff,
2371 read_exit_delay, read_exit_burst,
2372 nocbs_nthreads, nocbs_toggle);
2373}
2374
2375static int rcutorture_booster_cleanup(unsigned int cpu)
2376{
2377 struct task_struct *t;
2378
2379 if (boost_tasks[cpu] == NULL)
2380 return 0;
2381 mutex_lock(&boost_mutex);
2382 t = boost_tasks[cpu];
2383 boost_tasks[cpu] = NULL;
2384 rcu_torture_enable_rt_throttle();
2385 mutex_unlock(&boost_mutex);
2386
2387 /* This must be outside of the mutex, otherwise deadlock! */
2388 torture_stop_kthread(rcu_torture_boost, t);
2389 return 0;
2390}
2391
2392static int rcutorture_booster_init(unsigned int cpu)
2393{
2394 int retval;
2395
2396 if (boost_tasks[cpu] != NULL)
2397 return 0; /* Already created, nothing more to do. */
2398
2399 // Testing RCU priority boosting requires rcutorture do
2400 // some serious abuse. Counter this by running ksoftirqd
2401 // at higher priority.
2402 if (IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)) {
2403 struct sched_param sp;
2404 struct task_struct *t;
2405
2406 t = per_cpu(ksoftirqd, cpu);
2407 WARN_ON_ONCE(!t);
2408 sp.sched_priority = 2;
2409 sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
2410 }
2411
2412 /* Don't allow time recalculation while creating a new task. */
2413 mutex_lock(&boost_mutex);
2414 rcu_torture_disable_rt_throttle();
2415 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
2416 boost_tasks[cpu] = kthread_run_on_cpu(rcu_torture_boost, NULL,
2417 cpu, "rcu_torture_boost_%u");
2418 if (IS_ERR(boost_tasks[cpu])) {
2419 retval = PTR_ERR(boost_tasks[cpu]);
2420 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
2421 n_rcu_torture_boost_ktrerror++;
2422 boost_tasks[cpu] = NULL;
2423 mutex_unlock(&boost_mutex);
2424 return retval;
2425 }
2426 mutex_unlock(&boost_mutex);
2427 return 0;
2428}
2429
2430/*
2431 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
2432 * induces a CPU stall for the time specified by stall_cpu.
2433 */
2434static int rcu_torture_stall(void *args)
2435{
2436 int idx;
2437 unsigned long stop_at;
2438
2439 VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
2440 if (stall_cpu_holdoff > 0) {
2441 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
2442 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
2443 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
2444 }
2445 if (!kthread_should_stop() && stall_gp_kthread > 0) {
2446 VERBOSE_TOROUT_STRING("rcu_torture_stall begin GP stall");
2447 rcu_gp_set_torture_wait(stall_gp_kthread * HZ);
2448 for (idx = 0; idx < stall_gp_kthread + 2; idx++) {
2449 if (kthread_should_stop())
2450 break;
2451 schedule_timeout_uninterruptible(HZ);
2452 }
2453 }
2454 if (!kthread_should_stop() && stall_cpu > 0) {
2455 VERBOSE_TOROUT_STRING("rcu_torture_stall begin CPU stall");
2456 stop_at = ktime_get_seconds() + stall_cpu;
2457 /* RCU CPU stall is expected behavior in following code. */
2458 idx = cur_ops->readlock();
2459 if (stall_cpu_irqsoff)
2460 local_irq_disable();
2461 else if (!stall_cpu_block)
2462 preempt_disable();
2463 pr_alert("%s start on CPU %d.\n",
2464 __func__, raw_smp_processor_id());
2465 while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(),
2466 stop_at))
2467 if (stall_cpu_block) {
2468#ifdef CONFIG_PREEMPTION
2469 preempt_schedule();
2470#else
2471 schedule_timeout_uninterruptible(HZ);
2472#endif
2473 } else if (stall_no_softlockup) {
2474 touch_softlockup_watchdog();
2475 }
2476 if (stall_cpu_irqsoff)
2477 local_irq_enable();
2478 else if (!stall_cpu_block)
2479 preempt_enable();
2480 cur_ops->readunlock(idx);
2481 }
2482 pr_alert("%s end.\n", __func__);
2483 torture_shutdown_absorb("rcu_torture_stall");
2484 while (!kthread_should_stop())
2485 schedule_timeout_interruptible(10 * HZ);
2486 return 0;
2487}
2488
2489/* Spawn CPU-stall kthread, if stall_cpu specified. */
2490static int __init rcu_torture_stall_init(void)
2491{
2492 if (stall_cpu <= 0 && stall_gp_kthread <= 0)
2493 return 0;
2494 return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
2495}
2496
2497/* State structure for forward-progress self-propagating RCU callback. */
2498struct fwd_cb_state {
2499 struct rcu_head rh;
2500 int stop;
2501};
2502
2503/*
2504 * Forward-progress self-propagating RCU callback function. Because
2505 * callbacks run from softirq, this function is an implicit RCU read-side
2506 * critical section.
2507 */
2508static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp)
2509{
2510 struct fwd_cb_state *fcsp = container_of(rhp, struct fwd_cb_state, rh);
2511
2512 if (READ_ONCE(fcsp->stop)) {
2513 WRITE_ONCE(fcsp->stop, 2);
2514 return;
2515 }
2516 cur_ops->call(&fcsp->rh, rcu_torture_fwd_prog_cb);
2517}
2518
2519/* State for continuous-flood RCU callbacks. */
2520struct rcu_fwd_cb {
2521 struct rcu_head rh;
2522 struct rcu_fwd_cb *rfc_next;
2523 struct rcu_fwd *rfc_rfp;
2524 int rfc_gps;
2525};
2526
2527#define MAX_FWD_CB_JIFFIES (8 * HZ) /* Maximum CB test duration. */
2528#define MIN_FWD_CB_LAUNDERS 3 /* This many CB invocations to count. */
2529#define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */
2530#define FWD_CBS_HIST_DIV 10 /* Histogram buckets/second. */
2531#define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV))
2532
2533struct rcu_launder_hist {
2534 long n_launders;
2535 unsigned long launder_gp_seq;
2536};
2537
2538struct rcu_fwd {
2539 spinlock_t rcu_fwd_lock;
2540 struct rcu_fwd_cb *rcu_fwd_cb_head;
2541 struct rcu_fwd_cb **rcu_fwd_cb_tail;
2542 long n_launders_cb;
2543 unsigned long rcu_fwd_startat;
2544 struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST];
2545 unsigned long rcu_launder_gp_seq_start;
2546 int rcu_fwd_id;
2547};
2548
2549static DEFINE_MUTEX(rcu_fwd_mutex);
2550static struct rcu_fwd *rcu_fwds;
2551static unsigned long rcu_fwd_seq;
2552static atomic_long_t rcu_fwd_max_cbs;
2553static bool rcu_fwd_emergency_stop;
2554
2555static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp)
2556{
2557 unsigned long gps;
2558 unsigned long gps_old;
2559 int i;
2560 int j;
2561
2562 for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--)
2563 if (rfp->n_launders_hist[i].n_launders > 0)
2564 break;
2565 pr_alert("%s: Callback-invocation histogram %d (duration %lu jiffies):",
2566 __func__, rfp->rcu_fwd_id, jiffies - rfp->rcu_fwd_startat);
2567 gps_old = rfp->rcu_launder_gp_seq_start;
2568 for (j = 0; j <= i; j++) {
2569 gps = rfp->n_launders_hist[j].launder_gp_seq;
2570 pr_cont(" %ds/%d: %ld:%ld",
2571 j + 1, FWD_CBS_HIST_DIV,
2572 rfp->n_launders_hist[j].n_launders,
2573 rcutorture_seq_diff(gps, gps_old));
2574 gps_old = gps;
2575 }
2576 pr_cont("\n");
2577}
2578
2579/* Callback function for continuous-flood RCU callbacks. */
2580static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp)
2581{
2582 unsigned long flags;
2583 int i;
2584 struct rcu_fwd_cb *rfcp = container_of(rhp, struct rcu_fwd_cb, rh);
2585 struct rcu_fwd_cb **rfcpp;
2586 struct rcu_fwd *rfp = rfcp->rfc_rfp;
2587
2588 rfcp->rfc_next = NULL;
2589 rfcp->rfc_gps++;
2590 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
2591 rfcpp = rfp->rcu_fwd_cb_tail;
2592 rfp->rcu_fwd_cb_tail = &rfcp->rfc_next;
2593 WRITE_ONCE(*rfcpp, rfcp);
2594 WRITE_ONCE(rfp->n_launders_cb, rfp->n_launders_cb + 1);
2595 i = ((jiffies - rfp->rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV));
2596 if (i >= ARRAY_SIZE(rfp->n_launders_hist))
2597 i = ARRAY_SIZE(rfp->n_launders_hist) - 1;
2598 rfp->n_launders_hist[i].n_launders++;
2599 rfp->n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq();
2600 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
2601}
2602
2603// Give the scheduler a chance, even on nohz_full CPUs.
2604static void rcu_torture_fwd_prog_cond_resched(unsigned long iter)
2605{
2606 if (IS_ENABLED(CONFIG_PREEMPTION) && IS_ENABLED(CONFIG_NO_HZ_FULL)) {
2607 // Real call_rcu() floods hit userspace, so emulate that.
2608 if (need_resched() || (iter & 0xfff))
2609 schedule();
2610 return;
2611 }
2612 // No userspace emulation: CB invocation throttles call_rcu()
2613 cond_resched();
2614}
2615
2616/*
2617 * Free all callbacks on the rcu_fwd_cb_head list, either because the
2618 * test is over or because we hit an OOM event.
2619 */
2620static unsigned long rcu_torture_fwd_prog_cbfree(struct rcu_fwd *rfp)
2621{
2622 unsigned long flags;
2623 unsigned long freed = 0;
2624 struct rcu_fwd_cb *rfcp;
2625
2626 for (;;) {
2627 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
2628 rfcp = rfp->rcu_fwd_cb_head;
2629 if (!rfcp) {
2630 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
2631 break;
2632 }
2633 rfp->rcu_fwd_cb_head = rfcp->rfc_next;
2634 if (!rfp->rcu_fwd_cb_head)
2635 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head;
2636 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
2637 kfree(rfcp);
2638 freed++;
2639 rcu_torture_fwd_prog_cond_resched(freed);
2640 if (tick_nohz_full_enabled()) {
2641 local_irq_save(flags);
2642 rcu_momentary_dyntick_idle();
2643 local_irq_restore(flags);
2644 }
2645 }
2646 return freed;
2647}
2648
2649/* Carry out need_resched()/cond_resched() forward-progress testing. */
2650static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp,
2651 int *tested, int *tested_tries)
2652{
2653 unsigned long cver;
2654 unsigned long dur;
2655 struct fwd_cb_state fcs;
2656 unsigned long gps;
2657 int idx;
2658 int sd;
2659 int sd4;
2660 bool selfpropcb = false;
2661 unsigned long stopat;
2662 static DEFINE_TORTURE_RANDOM(trs);
2663
2664 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
2665 if (!cur_ops->sync)
2666 return; // Cannot do need_resched() forward progress testing without ->sync.
2667 if (cur_ops->call && cur_ops->cb_barrier) {
2668 init_rcu_head_on_stack(&fcs.rh);
2669 selfpropcb = true;
2670 }
2671
2672 /* Tight loop containing cond_resched(). */
2673 atomic_inc(&rcu_fwd_cb_nodelay);
2674 cur_ops->sync(); /* Later readers see above write. */
2675 if (selfpropcb) {
2676 WRITE_ONCE(fcs.stop, 0);
2677 cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb);
2678 }
2679 cver = READ_ONCE(rcu_torture_current_version);
2680 gps = cur_ops->get_gp_seq();
2681 sd = cur_ops->stall_dur() + 1;
2682 sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div;
2683 dur = sd4 + torture_random(&trs) % (sd - sd4);
2684 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
2685 stopat = rfp->rcu_fwd_startat + dur;
2686 while (time_before(jiffies, stopat) &&
2687 !shutdown_time_arrived() &&
2688 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
2689 idx = cur_ops->readlock();
2690 udelay(10);
2691 cur_ops->readunlock(idx);
2692 if (!fwd_progress_need_resched || need_resched())
2693 cond_resched();
2694 }
2695 (*tested_tries)++;
2696 if (!time_before(jiffies, stopat) &&
2697 !shutdown_time_arrived() &&
2698 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
2699 (*tested)++;
2700 cver = READ_ONCE(rcu_torture_current_version) - cver;
2701 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
2702 WARN_ON(!cver && gps < 2);
2703 pr_alert("%s: %d Duration %ld cver %ld gps %ld\n", __func__,
2704 rfp->rcu_fwd_id, dur, cver, gps);
2705 }
2706 if (selfpropcb) {
2707 WRITE_ONCE(fcs.stop, 1);
2708 cur_ops->sync(); /* Wait for running CB to complete. */
2709 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id);
2710 cur_ops->cb_barrier(); /* Wait for queued callbacks. */
2711 }
2712
2713 if (selfpropcb) {
2714 WARN_ON(READ_ONCE(fcs.stop) != 2);
2715 destroy_rcu_head_on_stack(&fcs.rh);
2716 }
2717 schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */
2718 atomic_dec(&rcu_fwd_cb_nodelay);
2719}
2720
2721/* Carry out call_rcu() forward-progress testing. */
2722static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp)
2723{
2724 unsigned long cver;
2725 unsigned long flags;
2726 unsigned long gps;
2727 int i;
2728 long n_launders;
2729 long n_launders_cb_snap;
2730 long n_launders_sa;
2731 long n_max_cbs;
2732 long n_max_gps;
2733 struct rcu_fwd_cb *rfcp;
2734 struct rcu_fwd_cb *rfcpn;
2735 unsigned long stopat;
2736 unsigned long stoppedat;
2737
2738 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
2739 if (READ_ONCE(rcu_fwd_emergency_stop))
2740 return; /* Get out of the way quickly, no GP wait! */
2741 if (!cur_ops->call)
2742 return; /* Can't do call_rcu() fwd prog without ->call. */
2743
2744 /* Loop continuously posting RCU callbacks. */
2745 atomic_inc(&rcu_fwd_cb_nodelay);
2746 cur_ops->sync(); /* Later readers see above write. */
2747 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
2748 stopat = rfp->rcu_fwd_startat + MAX_FWD_CB_JIFFIES;
2749 n_launders = 0;
2750 rfp->n_launders_cb = 0; // Hoist initialization for multi-kthread
2751 n_launders_sa = 0;
2752 n_max_cbs = 0;
2753 n_max_gps = 0;
2754 for (i = 0; i < ARRAY_SIZE(rfp->n_launders_hist); i++)
2755 rfp->n_launders_hist[i].n_launders = 0;
2756 cver = READ_ONCE(rcu_torture_current_version);
2757 gps = cur_ops->get_gp_seq();
2758 rfp->rcu_launder_gp_seq_start = gps;
2759 tick_dep_set_task(current, TICK_DEP_BIT_RCU);
2760 while (time_before(jiffies, stopat) &&
2761 !shutdown_time_arrived() &&
2762 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
2763 rfcp = READ_ONCE(rfp->rcu_fwd_cb_head);
2764 rfcpn = NULL;
2765 if (rfcp)
2766 rfcpn = READ_ONCE(rfcp->rfc_next);
2767 if (rfcpn) {
2768 if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS &&
2769 ++n_max_gps >= MIN_FWD_CBS_LAUNDERED)
2770 break;
2771 rfp->rcu_fwd_cb_head = rfcpn;
2772 n_launders++;
2773 n_launders_sa++;
2774 } else if (!cur_ops->cbflood_max || cur_ops->cbflood_max > n_max_cbs) {
2775 rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL);
2776 if (WARN_ON_ONCE(!rfcp)) {
2777 schedule_timeout_interruptible(1);
2778 continue;
2779 }
2780 n_max_cbs++;
2781 n_launders_sa = 0;
2782 rfcp->rfc_gps = 0;
2783 rfcp->rfc_rfp = rfp;
2784 } else {
2785 rfcp = NULL;
2786 }
2787 if (rfcp)
2788 cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr);
2789 rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs);
2790 if (tick_nohz_full_enabled()) {
2791 local_irq_save(flags);
2792 rcu_momentary_dyntick_idle();
2793 local_irq_restore(flags);
2794 }
2795 }
2796 stoppedat = jiffies;
2797 n_launders_cb_snap = READ_ONCE(rfp->n_launders_cb);
2798 cver = READ_ONCE(rcu_torture_current_version) - cver;
2799 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
2800 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id);
2801 cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */
2802 (void)rcu_torture_fwd_prog_cbfree(rfp);
2803
2804 if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) &&
2805 !shutdown_time_arrived()) {
2806 WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED);
2807 pr_alert("%s Duration %lu barrier: %lu pending %ld n_launders: %ld n_launders_sa: %ld n_max_gps: %ld n_max_cbs: %ld cver %ld gps %ld\n",
2808 __func__,
2809 stoppedat - rfp->rcu_fwd_startat, jiffies - stoppedat,
2810 n_launders + n_max_cbs - n_launders_cb_snap,
2811 n_launders, n_launders_sa,
2812 n_max_gps, n_max_cbs, cver, gps);
2813 atomic_long_add(n_max_cbs, &rcu_fwd_max_cbs);
2814 mutex_lock(&rcu_fwd_mutex); // Serialize histograms.
2815 rcu_torture_fwd_cb_hist(rfp);
2816 mutex_unlock(&rcu_fwd_mutex);
2817 }
2818 schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */
2819 tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
2820 atomic_dec(&rcu_fwd_cb_nodelay);
2821}
2822
2823
2824/*
2825 * OOM notifier, but this only prints diagnostic information for the
2826 * current forward-progress test.
2827 */
2828static int rcutorture_oom_notify(struct notifier_block *self,
2829 unsigned long notused, void *nfreed)
2830{
2831 int i;
2832 long ncbs;
2833 struct rcu_fwd *rfp;
2834
2835 mutex_lock(&rcu_fwd_mutex);
2836 rfp = rcu_fwds;
2837 if (!rfp) {
2838 mutex_unlock(&rcu_fwd_mutex);
2839 return NOTIFY_OK;
2840 }
2841 WARN(1, "%s invoked upon OOM during forward-progress testing.\n",
2842 __func__);
2843 for (i = 0; i < fwd_progress; i++) {
2844 rcu_torture_fwd_cb_hist(&rfp[i]);
2845 rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp[i].rcu_fwd_startat)) / 2);
2846 }
2847 WRITE_ONCE(rcu_fwd_emergency_stop, true);
2848 smp_mb(); /* Emergency stop before free and wait to avoid hangs. */
2849 ncbs = 0;
2850 for (i = 0; i < fwd_progress; i++)
2851 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
2852 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
2853 cur_ops->cb_barrier();
2854 ncbs = 0;
2855 for (i = 0; i < fwd_progress; i++)
2856 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
2857 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
2858 cur_ops->cb_barrier();
2859 ncbs = 0;
2860 for (i = 0; i < fwd_progress; i++)
2861 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
2862 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
2863 smp_mb(); /* Frees before return to avoid redoing OOM. */
2864 (*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */
2865 pr_info("%s returning after OOM processing.\n", __func__);
2866 mutex_unlock(&rcu_fwd_mutex);
2867 return NOTIFY_OK;
2868}
2869
2870static struct notifier_block rcutorture_oom_nb = {
2871 .notifier_call = rcutorture_oom_notify
2872};
2873
2874/* Carry out grace-period forward-progress testing. */
2875static int rcu_torture_fwd_prog(void *args)
2876{
2877 bool firsttime = true;
2878 long max_cbs;
2879 int oldnice = task_nice(current);
2880 unsigned long oldseq = READ_ONCE(rcu_fwd_seq);
2881 struct rcu_fwd *rfp = args;
2882 int tested = 0;
2883 int tested_tries = 0;
2884
2885 VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started");
2886 rcu_bind_current_to_nocb();
2887 if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST))
2888 set_user_nice(current, MAX_NICE);
2889 do {
2890 if (!rfp->rcu_fwd_id) {
2891 schedule_timeout_interruptible(fwd_progress_holdoff * HZ);
2892 WRITE_ONCE(rcu_fwd_emergency_stop, false);
2893 if (!firsttime) {
2894 max_cbs = atomic_long_xchg(&rcu_fwd_max_cbs, 0);
2895 pr_alert("%s n_max_cbs: %ld\n", __func__, max_cbs);
2896 }
2897 firsttime = false;
2898 WRITE_ONCE(rcu_fwd_seq, rcu_fwd_seq + 1);
2899 } else {
2900 while (READ_ONCE(rcu_fwd_seq) == oldseq && !torture_must_stop())
2901 schedule_timeout_interruptible(1);
2902 oldseq = READ_ONCE(rcu_fwd_seq);
2903 }
2904 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
2905 if (rcu_inkernel_boot_has_ended() && torture_num_online_cpus() > rfp->rcu_fwd_id)
2906 rcu_torture_fwd_prog_cr(rfp);
2907 if ((cur_ops->stall_dur && cur_ops->stall_dur() > 0) &&
2908 (!IS_ENABLED(CONFIG_TINY_RCU) ||
2909 (rcu_inkernel_boot_has_ended() &&
2910 torture_num_online_cpus() > rfp->rcu_fwd_id)))
2911 rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries);
2912
2913 /* Avoid slow periods, better to test when busy. */
2914 if (stutter_wait("rcu_torture_fwd_prog"))
2915 sched_set_normal(current, oldnice);
2916 } while (!torture_must_stop());
2917 /* Short runs might not contain a valid forward-progress attempt. */
2918 if (!rfp->rcu_fwd_id) {
2919 WARN_ON(!tested && tested_tries >= 5);
2920 pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries);
2921 }
2922 torture_kthread_stopping("rcu_torture_fwd_prog");
2923 return 0;
2924}
2925
2926/* If forward-progress checking is requested and feasible, spawn the thread. */
2927static int __init rcu_torture_fwd_prog_init(void)
2928{
2929 int i;
2930 int ret = 0;
2931 struct rcu_fwd *rfp;
2932
2933 if (!fwd_progress)
2934 return 0; /* Not requested, so don't do it. */
2935 if (fwd_progress >= nr_cpu_ids) {
2936 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Limiting fwd_progress to # CPUs.\n");
2937 fwd_progress = nr_cpu_ids;
2938 } else if (fwd_progress < 0) {
2939 fwd_progress = nr_cpu_ids;
2940 }
2941 if ((!cur_ops->sync && !cur_ops->call) ||
2942 (!cur_ops->cbflood_max && (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0)) ||
2943 cur_ops == &rcu_busted_ops) {
2944 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test");
2945 fwd_progress = 0;
2946 return 0;
2947 }
2948 if (stall_cpu > 0) {
2949 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing");
2950 fwd_progress = 0;
2951 if (IS_MODULE(CONFIG_RCU_TORTURE_TEST))
2952 return -EINVAL; /* In module, can fail back to user. */
2953 WARN_ON(1); /* Make sure rcutorture notices conflict. */
2954 return 0;
2955 }
2956 if (fwd_progress_holdoff <= 0)
2957 fwd_progress_holdoff = 1;
2958 if (fwd_progress_div <= 0)
2959 fwd_progress_div = 4;
2960 rfp = kcalloc(fwd_progress, sizeof(*rfp), GFP_KERNEL);
2961 fwd_prog_tasks = kcalloc(fwd_progress, sizeof(*fwd_prog_tasks), GFP_KERNEL);
2962 if (!rfp || !fwd_prog_tasks) {
2963 kfree(rfp);
2964 kfree(fwd_prog_tasks);
2965 fwd_prog_tasks = NULL;
2966 fwd_progress = 0;
2967 return -ENOMEM;
2968 }
2969 for (i = 0; i < fwd_progress; i++) {
2970 spin_lock_init(&rfp[i].rcu_fwd_lock);
2971 rfp[i].rcu_fwd_cb_tail = &rfp[i].rcu_fwd_cb_head;
2972 rfp[i].rcu_fwd_id = i;
2973 }
2974 mutex_lock(&rcu_fwd_mutex);
2975 rcu_fwds = rfp;
2976 mutex_unlock(&rcu_fwd_mutex);
2977 register_oom_notifier(&rcutorture_oom_nb);
2978 for (i = 0; i < fwd_progress; i++) {
2979 ret = torture_create_kthread(rcu_torture_fwd_prog, &rcu_fwds[i], fwd_prog_tasks[i]);
2980 if (ret) {
2981 fwd_progress = i;
2982 return ret;
2983 }
2984 }
2985 return 0;
2986}
2987
2988static void rcu_torture_fwd_prog_cleanup(void)
2989{
2990 int i;
2991 struct rcu_fwd *rfp;
2992
2993 if (!rcu_fwds || !fwd_prog_tasks)
2994 return;
2995 for (i = 0; i < fwd_progress; i++)
2996 torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_tasks[i]);
2997 unregister_oom_notifier(&rcutorture_oom_nb);
2998 mutex_lock(&rcu_fwd_mutex);
2999 rfp = rcu_fwds;
3000 rcu_fwds = NULL;
3001 mutex_unlock(&rcu_fwd_mutex);
3002 kfree(rfp);
3003 kfree(fwd_prog_tasks);
3004 fwd_prog_tasks = NULL;
3005}
3006
3007/* Callback function for RCU barrier testing. */
3008static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
3009{
3010 atomic_inc(&barrier_cbs_invoked);
3011}
3012
3013/* IPI handler to get callback posted on desired CPU, if online. */
3014static void rcu_torture_barrier1cb(void *rcu_void)
3015{
3016 struct rcu_head *rhp = rcu_void;
3017
3018 cur_ops->call(rhp, rcu_torture_barrier_cbf);
3019}
3020
3021/* kthread function to register callbacks used to test RCU barriers. */
3022static int rcu_torture_barrier_cbs(void *arg)
3023{
3024 long myid = (long)arg;
3025 bool lastphase = false;
3026 bool newphase;
3027 struct rcu_head rcu;
3028
3029 init_rcu_head_on_stack(&rcu);
3030 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
3031 set_user_nice(current, MAX_NICE);
3032 do {
3033 wait_event(barrier_cbs_wq[myid],
3034 (newphase =
3035 smp_load_acquire(&barrier_phase)) != lastphase ||
3036 torture_must_stop());
3037 lastphase = newphase;
3038 if (torture_must_stop())
3039 break;
3040 /*
3041 * The above smp_load_acquire() ensures barrier_phase load
3042 * is ordered before the following ->call().
3043 */
3044 if (smp_call_function_single(myid, rcu_torture_barrier1cb,
3045 &rcu, 1)) {
3046 // IPI failed, so use direct call from current CPU.
3047 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
3048 }
3049 if (atomic_dec_and_test(&barrier_cbs_count))
3050 wake_up(&barrier_wq);
3051 } while (!torture_must_stop());
3052 if (cur_ops->cb_barrier != NULL)
3053 cur_ops->cb_barrier();
3054 destroy_rcu_head_on_stack(&rcu);
3055 torture_kthread_stopping("rcu_torture_barrier_cbs");
3056 return 0;
3057}
3058
3059/* kthread function to drive and coordinate RCU barrier testing. */
3060static int rcu_torture_barrier(void *arg)
3061{
3062 int i;
3063
3064 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
3065 do {
3066 atomic_set(&barrier_cbs_invoked, 0);
3067 atomic_set(&barrier_cbs_count, n_barrier_cbs);
3068 /* Ensure barrier_phase ordered after prior assignments. */
3069 smp_store_release(&barrier_phase, !barrier_phase);
3070 for (i = 0; i < n_barrier_cbs; i++)
3071 wake_up(&barrier_cbs_wq[i]);
3072 wait_event(barrier_wq,
3073 atomic_read(&barrier_cbs_count) == 0 ||
3074 torture_must_stop());
3075 if (torture_must_stop())
3076 break;
3077 n_barrier_attempts++;
3078 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
3079 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
3080 n_rcu_torture_barrier_error++;
3081 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
3082 atomic_read(&barrier_cbs_invoked),
3083 n_barrier_cbs);
3084 WARN_ON(1);
3085 // Wait manually for the remaining callbacks
3086 i = 0;
3087 do {
3088 if (WARN_ON(i++ > HZ))
3089 i = INT_MIN;
3090 schedule_timeout_interruptible(1);
3091 cur_ops->cb_barrier();
3092 } while (atomic_read(&barrier_cbs_invoked) !=
3093 n_barrier_cbs &&
3094 !torture_must_stop());
3095 smp_mb(); // Can't trust ordering if broken.
3096 if (!torture_must_stop())
3097 pr_err("Recovered: barrier_cbs_invoked = %d\n",
3098 atomic_read(&barrier_cbs_invoked));
3099 } else {
3100 n_barrier_successes++;
3101 }
3102 schedule_timeout_interruptible(HZ / 10);
3103 } while (!torture_must_stop());
3104 torture_kthread_stopping("rcu_torture_barrier");
3105 return 0;
3106}
3107
3108/* Initialize RCU barrier testing. */
3109static int rcu_torture_barrier_init(void)
3110{
3111 int i;
3112 int ret;
3113
3114 if (n_barrier_cbs <= 0)
3115 return 0;
3116 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
3117 pr_alert("%s" TORTURE_FLAG
3118 " Call or barrier ops missing for %s,\n",
3119 torture_type, cur_ops->name);
3120 pr_alert("%s" TORTURE_FLAG
3121 " RCU barrier testing omitted from run.\n",
3122 torture_type);
3123 return 0;
3124 }
3125 atomic_set(&barrier_cbs_count, 0);
3126 atomic_set(&barrier_cbs_invoked, 0);
3127 barrier_cbs_tasks =
3128 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]),
3129 GFP_KERNEL);
3130 barrier_cbs_wq =
3131 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL);
3132 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
3133 return -ENOMEM;
3134 for (i = 0; i < n_barrier_cbs; i++) {
3135 init_waitqueue_head(&barrier_cbs_wq[i]);
3136 ret = torture_create_kthread(rcu_torture_barrier_cbs,
3137 (void *)(long)i,
3138 barrier_cbs_tasks[i]);
3139 if (ret)
3140 return ret;
3141 }
3142 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
3143}
3144
3145/* Clean up after RCU barrier testing. */
3146static void rcu_torture_barrier_cleanup(void)
3147{
3148 int i;
3149
3150 torture_stop_kthread(rcu_torture_barrier, barrier_task);
3151 if (barrier_cbs_tasks != NULL) {
3152 for (i = 0; i < n_barrier_cbs; i++)
3153 torture_stop_kthread(rcu_torture_barrier_cbs,
3154 barrier_cbs_tasks[i]);
3155 kfree(barrier_cbs_tasks);
3156 barrier_cbs_tasks = NULL;
3157 }
3158 if (barrier_cbs_wq != NULL) {
3159 kfree(barrier_cbs_wq);
3160 barrier_cbs_wq = NULL;
3161 }
3162}
3163
3164static bool rcu_torture_can_boost(void)
3165{
3166 static int boost_warn_once;
3167 int prio;
3168
3169 if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2)
3170 return false;
3171 if (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)
3172 return false;
3173
3174 prio = rcu_get_gp_kthreads_prio();
3175 if (!prio)
3176 return false;
3177
3178 if (prio < 2) {
3179 if (boost_warn_once == 1)
3180 return false;
3181
3182 pr_alert("%s: WARN: RCU kthread priority too low to test boosting. Skipping RCU boost test. Try passing rcutree.kthread_prio > 1 on the kernel command line.\n", KBUILD_MODNAME);
3183 boost_warn_once = 1;
3184 return false;
3185 }
3186
3187 return true;
3188}
3189
3190static bool read_exit_child_stop;
3191static bool read_exit_child_stopped;
3192static wait_queue_head_t read_exit_wq;
3193
3194// Child kthread which just does an rcutorture reader and exits.
3195static int rcu_torture_read_exit_child(void *trsp_in)
3196{
3197 struct torture_random_state *trsp = trsp_in;
3198
3199 set_user_nice(current, MAX_NICE);
3200 // Minimize time between reading and exiting.
3201 while (!kthread_should_stop())
3202 schedule_timeout_uninterruptible(1);
3203 (void)rcu_torture_one_read(trsp, -1);
3204 return 0;
3205}
3206
3207// Parent kthread which creates and destroys read-exit child kthreads.
3208static int rcu_torture_read_exit(void *unused)
3209{
3210 bool errexit = false;
3211 int i;
3212 struct task_struct *tsp;
3213 DEFINE_TORTURE_RANDOM(trs);
3214
3215 // Allocate and initialize.
3216 set_user_nice(current, MAX_NICE);
3217 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of test");
3218
3219 // Each pass through this loop does one read-exit episode.
3220 do {
3221 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of episode");
3222 for (i = 0; i < read_exit_burst; i++) {
3223 if (READ_ONCE(read_exit_child_stop))
3224 break;
3225 stutter_wait("rcu_torture_read_exit");
3226 // Spawn child.
3227 tsp = kthread_run(rcu_torture_read_exit_child,
3228 &trs, "%s", "rcu_torture_read_exit_child");
3229 if (IS_ERR(tsp)) {
3230 TOROUT_ERRSTRING("out of memory");
3231 errexit = true;
3232 break;
3233 }
3234 cond_resched();
3235 kthread_stop(tsp);
3236 n_read_exits++;
3237 }
3238 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: End of episode");
3239 rcu_barrier(); // Wait for task_struct free, avoid OOM.
3240 i = 0;
3241 for (; !errexit && !READ_ONCE(read_exit_child_stop) && i < read_exit_delay; i++)
3242 schedule_timeout_uninterruptible(HZ);
3243 } while (!errexit && !READ_ONCE(read_exit_child_stop));
3244
3245 // Clean up and exit.
3246 smp_store_release(&read_exit_child_stopped, true); // After reaping.
3247 smp_mb(); // Store before wakeup.
3248 wake_up(&read_exit_wq);
3249 while (!torture_must_stop())
3250 schedule_timeout_uninterruptible(1);
3251 torture_kthread_stopping("rcu_torture_read_exit");
3252 return 0;
3253}
3254
3255static int rcu_torture_read_exit_init(void)
3256{
3257 if (read_exit_burst <= 0)
3258 return 0;
3259 init_waitqueue_head(&read_exit_wq);
3260 read_exit_child_stop = false;
3261 read_exit_child_stopped = false;
3262 return torture_create_kthread(rcu_torture_read_exit, NULL,
3263 read_exit_task);
3264}
3265
3266static void rcu_torture_read_exit_cleanup(void)
3267{
3268 if (!read_exit_task)
3269 return;
3270 WRITE_ONCE(read_exit_child_stop, true);
3271 smp_mb(); // Above write before wait.
3272 wait_event(read_exit_wq, smp_load_acquire(&read_exit_child_stopped));
3273 torture_stop_kthread(rcutorture_read_exit, read_exit_task);
3274}
3275
3276static enum cpuhp_state rcutor_hp;
3277
3278static void
3279rcu_torture_cleanup(void)
3280{
3281 int firsttime;
3282 int flags = 0;
3283 unsigned long gp_seq = 0;
3284 int i;
3285
3286 if (torture_cleanup_begin()) {
3287 if (cur_ops->cb_barrier != NULL) {
3288 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier);
3289 cur_ops->cb_barrier();
3290 }
3291 rcu_gp_slow_unregister(NULL);
3292 return;
3293 }
3294 if (!cur_ops) {
3295 torture_cleanup_end();
3296 rcu_gp_slow_unregister(NULL);
3297 return;
3298 }
3299
3300 if (cur_ops->gp_kthread_dbg)
3301 cur_ops->gp_kthread_dbg();
3302 rcu_torture_read_exit_cleanup();
3303 rcu_torture_barrier_cleanup();
3304 rcu_torture_fwd_prog_cleanup();
3305 torture_stop_kthread(rcu_torture_stall, stall_task);
3306 torture_stop_kthread(rcu_torture_writer, writer_task);
3307
3308 if (nocb_tasks) {
3309 for (i = 0; i < nrealnocbers; i++)
3310 torture_stop_kthread(rcu_nocb_toggle, nocb_tasks[i]);
3311 kfree(nocb_tasks);
3312 nocb_tasks = NULL;
3313 }
3314
3315 if (reader_tasks) {
3316 for (i = 0; i < nrealreaders; i++)
3317 torture_stop_kthread(rcu_torture_reader,
3318 reader_tasks[i]);
3319 kfree(reader_tasks);
3320 reader_tasks = NULL;
3321 }
3322 kfree(rcu_torture_reader_mbchk);
3323 rcu_torture_reader_mbchk = NULL;
3324
3325 if (fakewriter_tasks) {
3326 for (i = 0; i < nfakewriters; i++)
3327 torture_stop_kthread(rcu_torture_fakewriter,
3328 fakewriter_tasks[i]);
3329 kfree(fakewriter_tasks);
3330 fakewriter_tasks = NULL;
3331 }
3332
3333 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq);
3334 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq);
3335 pr_alert("%s: End-test grace-period state: g%ld f%#x total-gps=%ld\n",
3336 cur_ops->name, (long)gp_seq, flags,
3337 rcutorture_seq_diff(gp_seq, start_gp_seq));
3338 torture_stop_kthread(rcu_torture_stats, stats_task);
3339 torture_stop_kthread(rcu_torture_fqs, fqs_task);
3340 if (rcu_torture_can_boost() && rcutor_hp >= 0)
3341 cpuhp_remove_state(rcutor_hp);
3342
3343 /*
3344 * Wait for all RCU callbacks to fire, then do torture-type-specific
3345 * cleanup operations.
3346 */
3347 if (cur_ops->cb_barrier != NULL) {
3348 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier);
3349 cur_ops->cb_barrier();
3350 }
3351 if (cur_ops->cleanup != NULL)
3352 cur_ops->cleanup();
3353
3354 rcu_torture_mem_dump_obj();
3355
3356 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
3357
3358 if (err_segs_recorded) {
3359 pr_alert("Failure/close-call rcutorture reader segments:\n");
3360 if (rt_read_nsegs == 0)
3361 pr_alert("\t: No segments recorded!!!\n");
3362 firsttime = 1;
3363 for (i = 0; i < rt_read_nsegs; i++) {
3364 pr_alert("\t%d: %#x ", i, err_segs[i].rt_readstate);
3365 if (err_segs[i].rt_delay_jiffies != 0) {
3366 pr_cont("%s%ldjiffies", firsttime ? "" : "+",
3367 err_segs[i].rt_delay_jiffies);
3368 firsttime = 0;
3369 }
3370 if (err_segs[i].rt_delay_ms != 0) {
3371 pr_cont("%s%ldms", firsttime ? "" : "+",
3372 err_segs[i].rt_delay_ms);
3373 firsttime = 0;
3374 }
3375 if (err_segs[i].rt_delay_us != 0) {
3376 pr_cont("%s%ldus", firsttime ? "" : "+",
3377 err_segs[i].rt_delay_us);
3378 firsttime = 0;
3379 }
3380 pr_cont("%s\n",
3381 err_segs[i].rt_preempted ? "preempted" : "");
3382
3383 }
3384 }
3385 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
3386 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
3387 else if (torture_onoff_failures())
3388 rcu_torture_print_module_parms(cur_ops,
3389 "End of test: RCU_HOTPLUG");
3390 else
3391 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
3392 torture_cleanup_end();
3393 rcu_gp_slow_unregister(&rcu_fwd_cb_nodelay);
3394}
3395
3396#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
3397static void rcu_torture_leak_cb(struct rcu_head *rhp)
3398{
3399}
3400
3401static void rcu_torture_err_cb(struct rcu_head *rhp)
3402{
3403 /*
3404 * This -might- happen due to race conditions, but is unlikely.
3405 * The scenario that leads to this happening is that the
3406 * first of the pair of duplicate callbacks is queued,
3407 * someone else starts a grace period that includes that
3408 * callback, then the second of the pair must wait for the
3409 * next grace period. Unlikely, but can happen. If it
3410 * does happen, the debug-objects subsystem won't have splatted.
3411 */
3412 pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME);
3413}
3414#endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
3415
3416/*
3417 * Verify that double-free causes debug-objects to complain, but only
3418 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
3419 * cannot be carried out.
3420 */
3421static void rcu_test_debug_objects(void)
3422{
3423#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
3424 struct rcu_head rh1;
3425 struct rcu_head rh2;
3426 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
3427
3428 init_rcu_head_on_stack(&rh1);
3429 init_rcu_head_on_stack(&rh2);
3430 pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME);
3431
3432 /* Try to queue the rh2 pair of callbacks for the same grace period. */
3433 preempt_disable(); /* Prevent preemption from interrupting test. */
3434 rcu_read_lock(); /* Make it impossible to finish a grace period. */
3435 call_rcu_hurry(&rh1, rcu_torture_leak_cb); /* Start grace period. */
3436 local_irq_disable(); /* Make it harder to start a new grace period. */
3437 call_rcu_hurry(&rh2, rcu_torture_leak_cb);
3438 call_rcu_hurry(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
3439 if (rhp) {
3440 call_rcu_hurry(rhp, rcu_torture_leak_cb);
3441 call_rcu_hurry(rhp, rcu_torture_err_cb); /* Another duplicate callback. */
3442 }
3443 local_irq_enable();
3444 rcu_read_unlock();
3445 preempt_enable();
3446
3447 /* Wait for them all to get done so we can safely return. */
3448 rcu_barrier();
3449 pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME);
3450 destroy_rcu_head_on_stack(&rh1);
3451 destroy_rcu_head_on_stack(&rh2);
3452 kfree(rhp);
3453#else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
3454 pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME);
3455#endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
3456}
3457
3458static void rcutorture_sync(void)
3459{
3460 static unsigned long n;
3461
3462 if (cur_ops->sync && !(++n & 0xfff))
3463 cur_ops->sync();
3464}
3465
3466static int __init
3467rcu_torture_init(void)
3468{
3469 long i;
3470 int cpu;
3471 int firsterr = 0;
3472 int flags = 0;
3473 unsigned long gp_seq = 0;
3474 static struct rcu_torture_ops *torture_ops[] = {
3475 &rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops, &busted_srcud_ops,
3476 TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS
3477 &trivial_ops,
3478 };
3479
3480 if (!torture_init_begin(torture_type, verbose))
3481 return -EBUSY;
3482
3483 /* Process args and tell the world that the torturer is on the job. */
3484 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
3485 cur_ops = torture_ops[i];
3486 if (strcmp(torture_type, cur_ops->name) == 0)
3487 break;
3488 }
3489 if (i == ARRAY_SIZE(torture_ops)) {
3490 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
3491 torture_type);
3492 pr_alert("rcu-torture types:");
3493 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
3494 pr_cont(" %s", torture_ops[i]->name);
3495 pr_cont("\n");
3496 firsterr = -EINVAL;
3497 cur_ops = NULL;
3498 goto unwind;
3499 }
3500 if (cur_ops->fqs == NULL && fqs_duration != 0) {
3501 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
3502 fqs_duration = 0;
3503 }
3504 if (cur_ops->init)
3505 cur_ops->init();
3506
3507 if (nreaders >= 0) {
3508 nrealreaders = nreaders;
3509 } else {
3510 nrealreaders = num_online_cpus() - 2 - nreaders;
3511 if (nrealreaders <= 0)
3512 nrealreaders = 1;
3513 }
3514 rcu_torture_print_module_parms(cur_ops, "Start of test");
3515 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq);
3516 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq);
3517 start_gp_seq = gp_seq;
3518 pr_alert("%s: Start-test grace-period state: g%ld f%#x\n",
3519 cur_ops->name, (long)gp_seq, flags);
3520
3521 /* Set up the freelist. */
3522
3523 INIT_LIST_HEAD(&rcu_torture_freelist);
3524 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
3525 rcu_tortures[i].rtort_mbtest = 0;
3526 list_add_tail(&rcu_tortures[i].rtort_free,
3527 &rcu_torture_freelist);
3528 }
3529
3530 /* Initialize the statistics so that each run gets its own numbers. */
3531
3532 rcu_torture_current = NULL;
3533 rcu_torture_current_version = 0;
3534 atomic_set(&n_rcu_torture_alloc, 0);
3535 atomic_set(&n_rcu_torture_alloc_fail, 0);
3536 atomic_set(&n_rcu_torture_free, 0);
3537 atomic_set(&n_rcu_torture_mberror, 0);
3538 atomic_set(&n_rcu_torture_mbchk_fail, 0);
3539 atomic_set(&n_rcu_torture_mbchk_tries, 0);
3540 atomic_set(&n_rcu_torture_error, 0);
3541 n_rcu_torture_barrier_error = 0;
3542 n_rcu_torture_boost_ktrerror = 0;
3543 n_rcu_torture_boost_rterror = 0;
3544 n_rcu_torture_boost_failure = 0;
3545 n_rcu_torture_boosts = 0;
3546 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
3547 atomic_set(&rcu_torture_wcount[i], 0);
3548 for_each_possible_cpu(cpu) {
3549 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
3550 per_cpu(rcu_torture_count, cpu)[i] = 0;
3551 per_cpu(rcu_torture_batch, cpu)[i] = 0;
3552 }
3553 }
3554 err_segs_recorded = 0;
3555 rt_read_nsegs = 0;
3556
3557 /* Start up the kthreads. */
3558
3559 rcu_torture_write_types();
3560 firsterr = torture_create_kthread(rcu_torture_writer, NULL,
3561 writer_task);
3562 if (torture_init_error(firsterr))
3563 goto unwind;
3564 if (nfakewriters > 0) {
3565 fakewriter_tasks = kcalloc(nfakewriters,
3566 sizeof(fakewriter_tasks[0]),
3567 GFP_KERNEL);
3568 if (fakewriter_tasks == NULL) {
3569 TOROUT_ERRSTRING("out of memory");
3570 firsterr = -ENOMEM;
3571 goto unwind;
3572 }
3573 }
3574 for (i = 0; i < nfakewriters; i++) {
3575 firsterr = torture_create_kthread(rcu_torture_fakewriter,
3576 NULL, fakewriter_tasks[i]);
3577 if (torture_init_error(firsterr))
3578 goto unwind;
3579 }
3580 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
3581 GFP_KERNEL);
3582 rcu_torture_reader_mbchk = kcalloc(nrealreaders, sizeof(*rcu_torture_reader_mbchk),
3583 GFP_KERNEL);
3584 if (!reader_tasks || !rcu_torture_reader_mbchk) {
3585 TOROUT_ERRSTRING("out of memory");
3586 firsterr = -ENOMEM;
3587 goto unwind;
3588 }
3589 for (i = 0; i < nrealreaders; i++) {
3590 rcu_torture_reader_mbchk[i].rtc_chkrdr = -1;
3591 firsterr = torture_create_kthread(rcu_torture_reader, (void *)i,
3592 reader_tasks[i]);
3593 if (torture_init_error(firsterr))
3594 goto unwind;
3595 }
3596 nrealnocbers = nocbs_nthreads;
3597 if (WARN_ON(nrealnocbers < 0))
3598 nrealnocbers = 1;
3599 if (WARN_ON(nocbs_toggle < 0))
3600 nocbs_toggle = HZ;
3601 if (nrealnocbers > 0) {
3602 nocb_tasks = kcalloc(nrealnocbers, sizeof(nocb_tasks[0]), GFP_KERNEL);
3603 if (nocb_tasks == NULL) {
3604 TOROUT_ERRSTRING("out of memory");
3605 firsterr = -ENOMEM;
3606 goto unwind;
3607 }
3608 } else {
3609 nocb_tasks = NULL;
3610 }
3611 for (i = 0; i < nrealnocbers; i++) {
3612 firsterr = torture_create_kthread(rcu_nocb_toggle, NULL, nocb_tasks[i]);
3613 if (torture_init_error(firsterr))
3614 goto unwind;
3615 }
3616 if (stat_interval > 0) {
3617 firsterr = torture_create_kthread(rcu_torture_stats, NULL,
3618 stats_task);
3619 if (torture_init_error(firsterr))
3620 goto unwind;
3621 }
3622 if (test_no_idle_hz && shuffle_interval > 0) {
3623 firsterr = torture_shuffle_init(shuffle_interval * HZ);
3624 if (torture_init_error(firsterr))
3625 goto unwind;
3626 }
3627 if (stutter < 0)
3628 stutter = 0;
3629 if (stutter) {
3630 int t;
3631
3632 t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ;
3633 firsterr = torture_stutter_init(stutter * HZ, t);
3634 if (torture_init_error(firsterr))
3635 goto unwind;
3636 }
3637 if (fqs_duration < 0)
3638 fqs_duration = 0;
3639 if (fqs_duration) {
3640 /* Create the fqs thread */
3641 firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
3642 fqs_task);
3643 if (torture_init_error(firsterr))
3644 goto unwind;
3645 }
3646 if (test_boost_interval < 1)
3647 test_boost_interval = 1;
3648 if (test_boost_duration < 2)
3649 test_boost_duration = 2;
3650 if (rcu_torture_can_boost()) {
3651
3652 boost_starttime = jiffies + test_boost_interval * HZ;
3653
3654 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE",
3655 rcutorture_booster_init,
3656 rcutorture_booster_cleanup);
3657 rcutor_hp = firsterr;
3658 if (torture_init_error(firsterr))
3659 goto unwind;
3660 }
3661 shutdown_jiffies = jiffies + shutdown_secs * HZ;
3662 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
3663 if (torture_init_error(firsterr))
3664 goto unwind;
3665 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval,
3666 rcutorture_sync);
3667 if (torture_init_error(firsterr))
3668 goto unwind;
3669 firsterr = rcu_torture_stall_init();
3670 if (torture_init_error(firsterr))
3671 goto unwind;
3672 firsterr = rcu_torture_fwd_prog_init();
3673 if (torture_init_error(firsterr))
3674 goto unwind;
3675 firsterr = rcu_torture_barrier_init();
3676 if (torture_init_error(firsterr))
3677 goto unwind;
3678 firsterr = rcu_torture_read_exit_init();
3679 if (torture_init_error(firsterr))
3680 goto unwind;
3681 if (object_debug)
3682 rcu_test_debug_objects();
3683 torture_init_end();
3684 rcu_gp_slow_register(&rcu_fwd_cb_nodelay);
3685 return 0;
3686
3687unwind:
3688 torture_init_end();
3689 rcu_torture_cleanup();
3690 if (shutdown_secs) {
3691 WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST));
3692 kernel_power_off();
3693 }
3694 return firsterr;
3695}
3696
3697module_init(rcu_torture_init);
3698module_exit(rcu_torture_cleanup);