2 * Read-Copy Update module-based torture test facility
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.
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.
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.
18 * Copyright (C) IBM Corporation, 2005, 2006
20 * Authors: Paul E. McKenney <paulmck@us.ibm.com>
21 * Josh Triplett <josh@joshtriplett.org>
23 * See also: Documentation/RCU/torture.txt
26 #define pr_fmt(fmt) fmt
28 #include <linux/types.h>
29 #include <linux/kernel.h>
30 #include <linux/init.h>
31 #include <linux/module.h>
32 #include <linux/kthread.h>
33 #include <linux/err.h>
34 #include <linux/spinlock.h>
35 #include <linux/smp.h>
36 #include <linux/rcupdate.h>
37 #include <linux/interrupt.h>
38 #include <linux/sched/signal.h>
39 #include <uapi/linux/sched/types.h>
40 #include <linux/atomic.h>
41 #include <linux/bitops.h>
42 #include <linux/completion.h>
43 #include <linux/moduleparam.h>
44 #include <linux/percpu.h>
45 #include <linux/notifier.h>
46 #include <linux/reboot.h>
47 #include <linux/freezer.h>
48 #include <linux/cpu.h>
49 #include <linux/delay.h>
50 #include <linux/stat.h>
51 #include <linux/srcu.h>
52 #include <linux/slab.h>
53 #include <linux/trace_clock.h>
54 #include <asm/byteorder.h>
55 #include <linux/torture.h>
56 #include <linux/vmalloc.h>
57 #include <linux/sched/debug.h>
61 MODULE_LICENSE("GPL");
62 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
65 torture_param(int, cbflood_inter_holdoff, HZ,
66 "Holdoff between floods (jiffies)");
67 torture_param(int, cbflood_intra_holdoff, 1,
68 "Holdoff between bursts (jiffies)");
69 torture_param(int, cbflood_n_burst, 3, "# bursts in flood, zero to disable");
70 torture_param(int, cbflood_n_per_burst, 20000,
71 "# callbacks per burst in flood");
72 torture_param(int, fqs_duration, 0,
73 "Duration of fqs bursts (us), 0 to disable");
74 torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
75 torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
76 torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
77 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
78 torture_param(bool, gp_normal, false,
79 "Use normal (non-expedited) GP wait primitives");
80 torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
81 torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
82 torture_param(int, n_barrier_cbs, 0,
83 "# of callbacks/kthreads for barrier testing");
84 torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
85 torture_param(int, nreaders, -1, "Number of RCU reader threads");
86 torture_param(int, object_debug, 0,
87 "Enable debug-object double call_rcu() testing");
88 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
89 torture_param(int, onoff_interval, 0,
90 "Time between CPU hotplugs (jiffies), 0=disable");
91 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
92 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
93 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
94 torture_param(int, stall_cpu_holdoff, 10,
95 "Time to wait before starting stall (s).");
96 torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling.");
97 torture_param(int, stat_interval, 60,
98 "Number of seconds between stats printk()s");
99 torture_param(int, stutter, 5, "Number of seconds to run/halt test");
100 torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
101 torture_param(int, test_boost_duration, 4,
102 "Duration of each boost test, seconds.");
103 torture_param(int, test_boost_interval, 7,
104 "Interval between boost tests, seconds.");
105 torture_param(bool, test_no_idle_hz, true,
106 "Test support for tickless idle CPUs");
107 torture_param(int, verbose, 1,
108 "Enable verbose debugging printk()s");
110 static char *torture_type = "rcu";
111 module_param(torture_type, charp, 0444);
112 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, ...)");
114 static int nrealreaders;
115 static int ncbflooders;
116 static struct task_struct *writer_task;
117 static struct task_struct **fakewriter_tasks;
118 static struct task_struct **reader_tasks;
119 static struct task_struct *stats_task;
120 static struct task_struct **cbflood_task;
121 static struct task_struct *fqs_task;
122 static struct task_struct *boost_tasks[NR_CPUS];
123 static struct task_struct *stall_task;
124 static struct task_struct **barrier_cbs_tasks;
125 static struct task_struct *barrier_task;
127 #define RCU_TORTURE_PIPE_LEN 10
130 struct rcu_head rtort_rcu;
131 int rtort_pipe_count;
132 struct list_head rtort_free;
136 static LIST_HEAD(rcu_torture_freelist);
137 static struct rcu_torture __rcu *rcu_torture_current;
138 static unsigned long rcu_torture_current_version;
139 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
140 static DEFINE_SPINLOCK(rcu_torture_lock);
141 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count);
142 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch);
143 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
144 static atomic_t n_rcu_torture_alloc;
145 static atomic_t n_rcu_torture_alloc_fail;
146 static atomic_t n_rcu_torture_free;
147 static atomic_t n_rcu_torture_mberror;
148 static atomic_t n_rcu_torture_error;
149 static long n_rcu_torture_barrier_error;
150 static long n_rcu_torture_boost_ktrerror;
151 static long n_rcu_torture_boost_rterror;
152 static long n_rcu_torture_boost_failure;
153 static long n_rcu_torture_boosts;
154 static atomic_long_t n_rcu_torture_timers;
155 static long n_barrier_attempts;
156 static long n_barrier_successes;
157 static atomic_long_t n_cbfloods;
158 static struct list_head rcu_torture_removed;
160 static int rcu_torture_writer_state;
161 #define RTWS_FIXED_DELAY 0
163 #define RTWS_REPLACE 2
164 #define RTWS_DEF_FREE 3
165 #define RTWS_EXP_SYNC 4
166 #define RTWS_COND_GET 5
167 #define RTWS_COND_SYNC 6
169 #define RTWS_STUTTER 8
170 #define RTWS_STOPPING 9
171 static const char * const rcu_torture_writer_state_names[] = {
184 static const char *rcu_torture_writer_state_getname(void)
186 unsigned int i = READ_ONCE(rcu_torture_writer_state);
188 if (i >= ARRAY_SIZE(rcu_torture_writer_state_names))
190 return rcu_torture_writer_state_names[i];
193 #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
194 #define rcu_can_boost() 1
195 #else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
196 #define rcu_can_boost() 0
197 #endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
199 #ifdef CONFIG_RCU_TRACE
200 static u64 notrace rcu_trace_clock_local(void)
202 u64 ts = trace_clock_local();
204 (void)do_div(ts, NSEC_PER_USEC);
207 #else /* #ifdef CONFIG_RCU_TRACE */
208 static u64 notrace rcu_trace_clock_local(void)
212 #endif /* #else #ifdef CONFIG_RCU_TRACE */
214 static unsigned long boost_starttime; /* jiffies of next boost test start. */
215 static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
216 /* and boost task create/destroy. */
217 static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
218 static bool barrier_phase; /* Test phase. */
219 static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
220 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
221 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
224 * Allocate an element from the rcu_tortures pool.
226 static struct rcu_torture *
227 rcu_torture_alloc(void)
231 spin_lock_bh(&rcu_torture_lock);
232 if (list_empty(&rcu_torture_freelist)) {
233 atomic_inc(&n_rcu_torture_alloc_fail);
234 spin_unlock_bh(&rcu_torture_lock);
237 atomic_inc(&n_rcu_torture_alloc);
238 p = rcu_torture_freelist.next;
240 spin_unlock_bh(&rcu_torture_lock);
241 return container_of(p, struct rcu_torture, rtort_free);
245 * Free an element to the rcu_tortures pool.
248 rcu_torture_free(struct rcu_torture *p)
250 atomic_inc(&n_rcu_torture_free);
251 spin_lock_bh(&rcu_torture_lock);
252 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
253 spin_unlock_bh(&rcu_torture_lock);
257 * Operations vector for selecting different types of tests.
260 struct rcu_torture_ops {
263 void (*cleanup)(void);
264 int (*readlock)(void);
265 void (*read_delay)(struct torture_random_state *rrsp);
266 void (*readunlock)(int idx);
267 unsigned long (*get_gp_seq)(void);
268 unsigned long (*gp_diff)(unsigned long new, unsigned long old);
269 void (*deferred_free)(struct rcu_torture *p);
271 void (*exp_sync)(void);
272 unsigned long (*get_state)(void);
273 void (*cond_sync)(unsigned long oldstate);
274 call_rcu_func_t call;
275 void (*cb_barrier)(void);
283 static struct rcu_torture_ops *cur_ops;
286 * Definitions for rcu torture testing.
289 static int rcu_torture_read_lock(void) __acquires(RCU)
295 static void rcu_read_delay(struct torture_random_state *rrsp)
297 unsigned long started;
298 unsigned long completed;
299 const unsigned long shortdelay_us = 200;
300 const unsigned long longdelay_ms = 50;
301 unsigned long long ts;
303 /* We want a short delay sometimes to make a reader delay the grace
304 * period, and we want a long delay occasionally to trigger
305 * force_quiescent_state. */
307 if (!(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) {
308 started = cur_ops->get_gp_seq();
309 ts = rcu_trace_clock_local();
310 mdelay(longdelay_ms);
311 completed = cur_ops->get_gp_seq();
312 do_trace_rcu_torture_read(cur_ops->name, NULL, ts,
315 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
316 udelay(shortdelay_us);
317 if (!preempt_count() &&
318 !(torture_random(rrsp) % (nrealreaders * 500)))
319 torture_preempt_schedule(); /* QS only if preemptible. */
322 static void rcu_torture_read_unlock(int idx) __releases(RCU)
328 * Update callback in the pipe. This should be invoked after a grace period.
331 rcu_torture_pipe_update_one(struct rcu_torture *rp)
335 i = rp->rtort_pipe_count;
336 if (i > RCU_TORTURE_PIPE_LEN)
337 i = RCU_TORTURE_PIPE_LEN;
338 atomic_inc(&rcu_torture_wcount[i]);
339 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
340 rp->rtort_mbtest = 0;
347 * Update all callbacks in the pipe. Suitable for synchronous grace-period
351 rcu_torture_pipe_update(struct rcu_torture *old_rp)
353 struct rcu_torture *rp;
354 struct rcu_torture *rp1;
357 list_add(&old_rp->rtort_free, &rcu_torture_removed);
358 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
359 if (rcu_torture_pipe_update_one(rp)) {
360 list_del(&rp->rtort_free);
361 rcu_torture_free(rp);
367 rcu_torture_cb(struct rcu_head *p)
369 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
371 if (torture_must_stop_irq()) {
372 /* Test is ending, just drop callbacks on the floor. */
373 /* The next initialization will pick up the pieces. */
376 if (rcu_torture_pipe_update_one(rp))
377 rcu_torture_free(rp);
379 cur_ops->deferred_free(rp);
382 static unsigned long rcu_no_completed(void)
387 static void rcu_torture_deferred_free(struct rcu_torture *p)
389 call_rcu(&p->rtort_rcu, rcu_torture_cb);
392 static void rcu_sync_torture_init(void)
394 INIT_LIST_HEAD(&rcu_torture_removed);
397 static struct rcu_torture_ops rcu_ops = {
399 .init = rcu_sync_torture_init,
400 .readlock = rcu_torture_read_lock,
401 .read_delay = rcu_read_delay,
402 .readunlock = rcu_torture_read_unlock,
403 .get_gp_seq = rcu_get_gp_seq,
404 .gp_diff = rcu_seq_diff,
405 .deferred_free = rcu_torture_deferred_free,
406 .sync = synchronize_rcu,
407 .exp_sync = synchronize_rcu_expedited,
408 .get_state = get_state_synchronize_rcu,
409 .cond_sync = cond_synchronize_rcu,
411 .cb_barrier = rcu_barrier,
412 .fqs = rcu_force_quiescent_state,
415 .can_boost = rcu_can_boost(),
420 * Definitions for rcu_bh torture testing.
423 static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
429 static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
431 rcu_read_unlock_bh();
434 static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
436 call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
439 static struct rcu_torture_ops rcu_bh_ops = {
440 .ttype = RCU_BH_FLAVOR,
441 .init = rcu_sync_torture_init,
442 .readlock = rcu_bh_torture_read_lock,
443 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
444 .readunlock = rcu_bh_torture_read_unlock,
445 .get_gp_seq = rcu_bh_get_gp_seq,
446 .gp_diff = rcu_seq_diff,
447 .deferred_free = rcu_bh_torture_deferred_free,
448 .sync = synchronize_rcu_bh,
449 .exp_sync = synchronize_rcu_bh_expedited,
451 .cb_barrier = rcu_barrier_bh,
452 .fqs = rcu_bh_force_quiescent_state,
459 * Don't even think about trying any of these in real life!!!
460 * The names includes "busted", and they really means it!
461 * The only purpose of these functions is to provide a buggy RCU
462 * implementation to make sure that rcutorture correctly emits
463 * buggy-RCU error messages.
465 static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
467 /* This is a deliberate bug for testing purposes only! */
468 rcu_torture_cb(&p->rtort_rcu);
471 static void synchronize_rcu_busted(void)
473 /* This is a deliberate bug for testing purposes only! */
477 call_rcu_busted(struct rcu_head *head, rcu_callback_t func)
479 /* This is a deliberate bug for testing purposes only! */
483 static struct rcu_torture_ops rcu_busted_ops = {
484 .ttype = INVALID_RCU_FLAVOR,
485 .init = rcu_sync_torture_init,
486 .readlock = rcu_torture_read_lock,
487 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
488 .readunlock = rcu_torture_read_unlock,
489 .get_gp_seq = rcu_no_completed,
490 .deferred_free = rcu_busted_torture_deferred_free,
491 .sync = synchronize_rcu_busted,
492 .exp_sync = synchronize_rcu_busted,
493 .call = call_rcu_busted,
502 * Definitions for srcu torture testing.
505 DEFINE_STATIC_SRCU(srcu_ctl);
506 static struct srcu_struct srcu_ctld;
507 static struct srcu_struct *srcu_ctlp = &srcu_ctl;
509 static int srcu_torture_read_lock(void) __acquires(srcu_ctlp)
511 return srcu_read_lock(srcu_ctlp);
514 static void srcu_read_delay(struct torture_random_state *rrsp)
517 const long uspertick = 1000000 / HZ;
518 const long longdelay = 10;
520 /* We want there to be long-running readers, but not all the time. */
522 delay = torture_random(rrsp) %
523 (nrealreaders * 2 * longdelay * uspertick);
524 if (!delay && in_task())
525 schedule_timeout_interruptible(longdelay);
527 rcu_read_delay(rrsp);
530 static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp)
532 srcu_read_unlock(srcu_ctlp, idx);
535 static unsigned long srcu_torture_completed(void)
537 return srcu_batches_completed(srcu_ctlp);
540 static void srcu_torture_deferred_free(struct rcu_torture *rp)
542 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
545 static void srcu_torture_synchronize(void)
547 synchronize_srcu(srcu_ctlp);
550 static void srcu_torture_call(struct rcu_head *head,
553 call_srcu(srcu_ctlp, head, func);
556 static void srcu_torture_barrier(void)
558 srcu_barrier(srcu_ctlp);
561 static void srcu_torture_stats(void)
563 srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG);
566 static void srcu_torture_synchronize_expedited(void)
568 synchronize_srcu_expedited(srcu_ctlp);
571 static struct rcu_torture_ops srcu_ops = {
572 .ttype = SRCU_FLAVOR,
573 .init = rcu_sync_torture_init,
574 .readlock = srcu_torture_read_lock,
575 .read_delay = srcu_read_delay,
576 .readunlock = srcu_torture_read_unlock,
577 .get_gp_seq = srcu_torture_completed,
578 .deferred_free = srcu_torture_deferred_free,
579 .sync = srcu_torture_synchronize,
580 .exp_sync = srcu_torture_synchronize_expedited,
581 .call = srcu_torture_call,
582 .cb_barrier = srcu_torture_barrier,
583 .stats = srcu_torture_stats,
588 static void srcu_torture_init(void)
590 rcu_sync_torture_init();
591 WARN_ON(init_srcu_struct(&srcu_ctld));
592 srcu_ctlp = &srcu_ctld;
595 static void srcu_torture_cleanup(void)
597 static DEFINE_TORTURE_RANDOM(rand);
599 if (torture_random(&rand) & 0x800)
600 cleanup_srcu_struct(&srcu_ctld);
602 cleanup_srcu_struct_quiesced(&srcu_ctld);
603 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
606 /* As above, but dynamically allocated. */
607 static struct rcu_torture_ops srcud_ops = {
608 .ttype = SRCU_FLAVOR,
609 .init = srcu_torture_init,
610 .cleanup = srcu_torture_cleanup,
611 .readlock = srcu_torture_read_lock,
612 .read_delay = srcu_read_delay,
613 .readunlock = srcu_torture_read_unlock,
614 .get_gp_seq = srcu_torture_completed,
615 .deferred_free = srcu_torture_deferred_free,
616 .sync = srcu_torture_synchronize,
617 .exp_sync = srcu_torture_synchronize_expedited,
618 .call = srcu_torture_call,
619 .cb_barrier = srcu_torture_barrier,
620 .stats = srcu_torture_stats,
626 * Definitions for sched torture testing.
629 static int sched_torture_read_lock(void)
635 static void sched_torture_read_unlock(int idx)
640 static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
642 call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
645 static struct rcu_torture_ops sched_ops = {
646 .ttype = RCU_SCHED_FLAVOR,
647 .init = rcu_sync_torture_init,
648 .readlock = sched_torture_read_lock,
649 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
650 .readunlock = sched_torture_read_unlock,
651 .get_gp_seq = rcu_sched_get_gp_seq,
652 .gp_diff = rcu_seq_diff,
653 .deferred_free = rcu_sched_torture_deferred_free,
654 .sync = synchronize_sched,
655 .exp_sync = synchronize_sched_expedited,
656 .get_state = get_state_synchronize_sched,
657 .cond_sync = cond_synchronize_sched,
658 .call = call_rcu_sched,
659 .cb_barrier = rcu_barrier_sched,
660 .fqs = rcu_sched_force_quiescent_state,
667 * Definitions for RCU-tasks torture testing.
670 static int tasks_torture_read_lock(void)
675 static void tasks_torture_read_unlock(int idx)
679 static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
681 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
684 static struct rcu_torture_ops tasks_ops = {
685 .ttype = RCU_TASKS_FLAVOR,
686 .init = rcu_sync_torture_init,
687 .readlock = tasks_torture_read_lock,
688 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
689 .readunlock = tasks_torture_read_unlock,
690 .get_gp_seq = rcu_no_completed,
691 .deferred_free = rcu_tasks_torture_deferred_free,
692 .sync = synchronize_rcu_tasks,
693 .exp_sync = synchronize_rcu_tasks,
694 .call = call_rcu_tasks,
695 .cb_barrier = rcu_barrier_tasks,
702 static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old)
704 if (!cur_ops->gp_diff)
706 return cur_ops->gp_diff(new, old);
709 static bool __maybe_unused torturing_tasks(void)
711 return cur_ops == &tasks_ops;
715 * RCU torture priority-boost testing. Runs one real-time thread per
716 * CPU for moderate bursts, repeatedly registering RCU callbacks and
717 * spinning waiting for them to be invoked. If a given callback takes
718 * too long to be invoked, we assume that priority inversion has occurred.
721 struct rcu_boost_inflight {
726 static void rcu_torture_boost_cb(struct rcu_head *head)
728 struct rcu_boost_inflight *rbip =
729 container_of(head, struct rcu_boost_inflight, rcu);
731 /* Ensure RCU-core accesses precede clearing ->inflight */
732 smp_store_release(&rbip->inflight, 0);
735 static int rcu_torture_boost(void *arg)
737 unsigned long call_rcu_time;
738 unsigned long endtime;
739 unsigned long oldstarttime;
740 struct rcu_boost_inflight rbi = { .inflight = 0 };
741 struct sched_param sp;
743 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
745 /* Set real-time priority. */
746 sp.sched_priority = 1;
747 if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
748 VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!");
749 n_rcu_torture_boost_rterror++;
752 init_rcu_head_on_stack(&rbi.rcu);
753 /* Each pass through the following loop does one boost-test cycle. */
755 /* Wait for the next test interval. */
756 oldstarttime = boost_starttime;
757 while (ULONG_CMP_LT(jiffies, oldstarttime)) {
758 schedule_timeout_interruptible(oldstarttime - jiffies);
759 stutter_wait("rcu_torture_boost");
760 if (torture_must_stop())
764 /* Do one boost-test interval. */
765 endtime = oldstarttime + test_boost_duration * HZ;
766 call_rcu_time = jiffies;
767 while (ULONG_CMP_LT(jiffies, endtime)) {
768 /* If we don't have a callback in flight, post one. */
769 if (!smp_load_acquire(&rbi.inflight)) {
770 /* RCU core before ->inflight = 1. */
771 smp_store_release(&rbi.inflight, 1);
772 call_rcu(&rbi.rcu, rcu_torture_boost_cb);
773 if (jiffies - call_rcu_time >
774 test_boost_duration * HZ - HZ / 2) {
775 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
776 n_rcu_torture_boost_failure++;
778 call_rcu_time = jiffies;
780 stutter_wait("rcu_torture_boost");
781 if (torture_must_stop())
786 * Set the start time of the next test interval.
787 * Yes, this is vulnerable to long delays, but such
788 * delays simply cause a false negative for the next
789 * interval. Besides, we are running at RT priority,
790 * so delays should be relatively rare.
792 while (oldstarttime == boost_starttime &&
793 !kthread_should_stop()) {
794 if (mutex_trylock(&boost_mutex)) {
795 boost_starttime = jiffies +
796 test_boost_interval * HZ;
797 n_rcu_torture_boosts++;
798 mutex_unlock(&boost_mutex);
801 schedule_timeout_uninterruptible(1);
804 /* Go do the stutter. */
805 checkwait: stutter_wait("rcu_torture_boost");
806 } while (!torture_must_stop());
808 /* Clean up and exit. */
809 while (!kthread_should_stop() || smp_load_acquire(&rbi.inflight)) {
810 torture_shutdown_absorb("rcu_torture_boost");
811 schedule_timeout_uninterruptible(1);
813 destroy_rcu_head_on_stack(&rbi.rcu);
814 torture_kthread_stopping("rcu_torture_boost");
818 static void rcu_torture_cbflood_cb(struct rcu_head *rhp)
823 * RCU torture callback-flood kthread. Repeatedly induces bursts of calls
824 * to call_rcu() or analogous, increasing the probability of occurrence
825 * of callback-overflow corner cases.
828 rcu_torture_cbflood(void *arg)
833 struct rcu_head *rhp;
835 if (cbflood_n_per_burst > 0 &&
836 cbflood_inter_holdoff > 0 &&
837 cbflood_intra_holdoff > 0 &&
839 cur_ops->cb_barrier) {
840 rhp = vmalloc(array3_size(cbflood_n_burst,
846 VERBOSE_TOROUT_STRING("rcu_torture_cbflood disabled: Bad args or OOM");
849 VERBOSE_TOROUT_STRING("rcu_torture_cbflood task started");
851 schedule_timeout_interruptible(cbflood_inter_holdoff);
852 atomic_long_inc(&n_cbfloods);
853 WARN_ON(signal_pending(current));
854 for (i = 0; i < cbflood_n_burst; i++) {
855 for (j = 0; j < cbflood_n_per_burst; j++) {
856 cur_ops->call(&rhp[i * cbflood_n_per_burst + j],
857 rcu_torture_cbflood_cb);
859 schedule_timeout_interruptible(cbflood_intra_holdoff);
860 WARN_ON(signal_pending(current));
862 cur_ops->cb_barrier();
863 stutter_wait("rcu_torture_cbflood");
864 } while (!torture_must_stop());
867 torture_kthread_stopping("rcu_torture_cbflood");
872 * RCU torture force-quiescent-state kthread. Repeatedly induces
873 * bursts of calls to force_quiescent_state(), increasing the probability
874 * of occurrence of some important types of race conditions.
877 rcu_torture_fqs(void *arg)
879 unsigned long fqs_resume_time;
880 int fqs_burst_remaining;
882 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
884 fqs_resume_time = jiffies + fqs_stutter * HZ;
885 while (ULONG_CMP_LT(jiffies, fqs_resume_time) &&
886 !kthread_should_stop()) {
887 schedule_timeout_interruptible(1);
889 fqs_burst_remaining = fqs_duration;
890 while (fqs_burst_remaining > 0 &&
891 !kthread_should_stop()) {
894 fqs_burst_remaining -= fqs_holdoff;
896 stutter_wait("rcu_torture_fqs");
897 } while (!torture_must_stop());
898 torture_kthread_stopping("rcu_torture_fqs");
903 * RCU torture writer kthread. Repeatedly substitutes a new structure
904 * for that pointed to by rcu_torture_current, freeing the old structure
905 * after a series of grace periods (the "pipeline").
908 rcu_torture_writer(void *arg)
910 bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
912 unsigned long gp_snap;
913 bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal;
914 bool gp_sync1 = gp_sync;
916 struct rcu_torture *rp;
917 struct rcu_torture *old_rp;
918 static DEFINE_TORTURE_RANDOM(rand);
919 int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC,
920 RTWS_COND_GET, RTWS_SYNC };
923 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
925 pr_alert("%s" TORTURE_FLAG
926 " GP expediting controlled from boot/sysfs for %s.\n",
927 torture_type, cur_ops->name);
929 /* Initialize synctype[] array. If none set, take default. */
930 if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync1)
931 gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true;
932 if (gp_cond1 && cur_ops->get_state && cur_ops->cond_sync) {
933 synctype[nsynctypes++] = RTWS_COND_GET;
934 pr_info("%s: Testing conditional GPs.\n", __func__);
935 } else if (gp_cond && (!cur_ops->get_state || !cur_ops->cond_sync)) {
936 pr_alert("%s: gp_cond without primitives.\n", __func__);
938 if (gp_exp1 && cur_ops->exp_sync) {
939 synctype[nsynctypes++] = RTWS_EXP_SYNC;
940 pr_info("%s: Testing expedited GPs.\n", __func__);
941 } else if (gp_exp && !cur_ops->exp_sync) {
942 pr_alert("%s: gp_exp without primitives.\n", __func__);
944 if (gp_normal1 && cur_ops->deferred_free) {
945 synctype[nsynctypes++] = RTWS_DEF_FREE;
946 pr_info("%s: Testing asynchronous GPs.\n", __func__);
947 } else if (gp_normal && !cur_ops->deferred_free) {
948 pr_alert("%s: gp_normal without primitives.\n", __func__);
950 if (gp_sync1 && cur_ops->sync) {
951 synctype[nsynctypes++] = RTWS_SYNC;
952 pr_info("%s: Testing normal GPs.\n", __func__);
953 } else if (gp_sync && !cur_ops->sync) {
954 pr_alert("%s: gp_sync without primitives.\n", __func__);
956 if (WARN_ONCE(nsynctypes == 0,
957 "rcu_torture_writer: No update-side primitives.\n")) {
959 * No updates primitives, so don't try updating.
960 * The resulting test won't be testing much, hence the
963 rcu_torture_writer_state = RTWS_STOPPING;
964 torture_kthread_stopping("rcu_torture_writer");
968 rcu_torture_writer_state = RTWS_FIXED_DELAY;
969 schedule_timeout_uninterruptible(1);
970 rp = rcu_torture_alloc();
973 rp->rtort_pipe_count = 0;
974 rcu_torture_writer_state = RTWS_DELAY;
975 udelay(torture_random(&rand) & 0x3ff);
976 rcu_torture_writer_state = RTWS_REPLACE;
977 old_rp = rcu_dereference_check(rcu_torture_current,
978 current == writer_task);
979 rp->rtort_mbtest = 1;
980 rcu_assign_pointer(rcu_torture_current, rp);
981 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
983 i = old_rp->rtort_pipe_count;
984 if (i > RCU_TORTURE_PIPE_LEN)
985 i = RCU_TORTURE_PIPE_LEN;
986 atomic_inc(&rcu_torture_wcount[i]);
987 old_rp->rtort_pipe_count++;
988 switch (synctype[torture_random(&rand) % nsynctypes]) {
990 rcu_torture_writer_state = RTWS_DEF_FREE;
991 cur_ops->deferred_free(old_rp);
994 rcu_torture_writer_state = RTWS_EXP_SYNC;
996 rcu_torture_pipe_update(old_rp);
999 rcu_torture_writer_state = RTWS_COND_GET;
1000 gp_snap = cur_ops->get_state();
1001 i = torture_random(&rand) % 16;
1003 schedule_timeout_interruptible(i);
1004 udelay(torture_random(&rand) % 1000);
1005 rcu_torture_writer_state = RTWS_COND_SYNC;
1006 cur_ops->cond_sync(gp_snap);
1007 rcu_torture_pipe_update(old_rp);
1010 rcu_torture_writer_state = RTWS_SYNC;
1012 rcu_torture_pipe_update(old_rp);
1019 rcu_torture_current_version++;
1020 /* Cycle through nesting levels of rcu_expedite_gp() calls. */
1022 !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
1023 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
1024 if (expediting >= 0)
1027 rcu_unexpedite_gp();
1028 if (++expediting > 3)
1029 expediting = -expediting;
1030 } else if (!can_expedite) { /* Disabled during boot, recheck. */
1031 can_expedite = !rcu_gp_is_expedited() &&
1032 !rcu_gp_is_normal();
1034 rcu_torture_writer_state = RTWS_STUTTER;
1035 stutter_wait("rcu_torture_writer");
1036 } while (!torture_must_stop());
1037 /* Reset expediting back to unexpedited. */
1039 expediting = -expediting;
1040 while (can_expedite && expediting++ < 0)
1041 rcu_unexpedite_gp();
1042 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
1044 pr_alert("%s" TORTURE_FLAG
1045 " Dynamic grace-period expediting was disabled.\n",
1047 rcu_torture_writer_state = RTWS_STOPPING;
1048 torture_kthread_stopping("rcu_torture_writer");
1053 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
1054 * delay between calls.
1057 rcu_torture_fakewriter(void *arg)
1059 DEFINE_TORTURE_RANDOM(rand);
1061 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1062 set_user_nice(current, MAX_NICE);
1065 schedule_timeout_uninterruptible(1 + torture_random(&rand)%10);
1066 udelay(torture_random(&rand) & 0x3ff);
1067 if (cur_ops->cb_barrier != NULL &&
1068 torture_random(&rand) % (nfakewriters * 8) == 0) {
1069 cur_ops->cb_barrier();
1070 } else if (gp_normal == gp_exp) {
1071 if (cur_ops->sync && torture_random(&rand) & 0x80)
1073 else if (cur_ops->exp_sync)
1074 cur_ops->exp_sync();
1075 } else if (gp_normal && cur_ops->sync) {
1077 } else if (cur_ops->exp_sync) {
1078 cur_ops->exp_sync();
1080 stutter_wait("rcu_torture_fakewriter");
1081 } while (!torture_must_stop());
1083 torture_kthread_stopping("rcu_torture_fakewriter");
1087 static void rcu_torture_timer_cb(struct rcu_head *rhp)
1093 * Do one read-side critical section, returning false if there was
1094 * no data to read. Can be invoked both from process context and
1095 * from a timer handler.
1097 static bool rcu_torture_one_read(struct torture_random_state *trsp)
1100 unsigned long started;
1101 unsigned long completed;
1102 struct rcu_torture *p;
1104 unsigned long long ts;
1106 idx = cur_ops->readlock();
1107 started = cur_ops->get_gp_seq();
1108 ts = rcu_trace_clock_local();
1109 p = rcu_dereference_check(rcu_torture_current,
1110 rcu_read_lock_bh_held() ||
1111 rcu_read_lock_sched_held() ||
1112 srcu_read_lock_held(srcu_ctlp) ||
1115 /* Wait for rcu_torture_writer to get underway */
1116 cur_ops->readunlock(idx);
1119 if (p->rtort_mbtest == 0)
1120 atomic_inc(&n_rcu_torture_mberror);
1121 cur_ops->read_delay(trsp);
1123 pipe_count = p->rtort_pipe_count;
1124 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1125 /* Should not happen, but... */
1126 pipe_count = RCU_TORTURE_PIPE_LEN;
1128 completed = cur_ops->get_gp_seq();
1129 if (pipe_count > 1) {
1130 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
1131 ts, started, completed);
1132 rcu_ftrace_dump(DUMP_ALL);
1134 __this_cpu_inc(rcu_torture_count[pipe_count]);
1135 completed = rcutorture_seq_diff(completed, started);
1136 if (completed > RCU_TORTURE_PIPE_LEN) {
1137 /* Should not happen, but... */
1138 completed = RCU_TORTURE_PIPE_LEN;
1140 __this_cpu_inc(rcu_torture_batch[completed]);
1142 cur_ops->readunlock(idx);
1147 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
1148 * incrementing the corresponding element of the pipeline array. The
1149 * counter in the element should never be greater than 1, otherwise, the
1150 * RCU implementation is broken.
1152 static void rcu_torture_timer(struct timer_list *unused)
1155 unsigned long started;
1156 unsigned long completed;
1157 static DEFINE_TORTURE_RANDOM(rand);
1158 static DEFINE_SPINLOCK(rand_lock);
1159 struct rcu_torture *p;
1161 unsigned long long ts;
1163 atomic_long_inc(&n_rcu_torture_timers);
1164 idx = cur_ops->readlock();
1165 started = cur_ops->get_gp_seq();
1166 ts = rcu_trace_clock_local();
1167 p = rcu_dereference_check(rcu_torture_current,
1168 rcu_read_lock_bh_held() ||
1169 rcu_read_lock_sched_held() ||
1170 srcu_read_lock_held(srcu_ctlp) ||
1173 /* Leave because rcu_torture_writer is not yet underway */
1174 cur_ops->readunlock(idx);
1177 if (p->rtort_mbtest == 0)
1178 atomic_inc(&n_rcu_torture_mberror);
1179 spin_lock(&rand_lock);
1180 cur_ops->read_delay(&rand);
1181 spin_unlock(&rand_lock);
1183 pipe_count = p->rtort_pipe_count;
1184 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1185 /* Should not happen, but... */
1186 pipe_count = RCU_TORTURE_PIPE_LEN;
1188 completed = cur_ops->get_gp_seq();
1189 if (pipe_count > 1) {
1190 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, ts,
1191 started, completed);
1192 rcu_ftrace_dump(DUMP_ALL);
1194 __this_cpu_inc(rcu_torture_count[pipe_count]);
1195 completed = rcutorture_seq_diff(completed, started);
1196 if (completed > RCU_TORTURE_PIPE_LEN) {
1197 /* Should not happen, but... */
1198 completed = RCU_TORTURE_PIPE_LEN;
1200 __this_cpu_inc(rcu_torture_batch[completed]);
1202 cur_ops->readunlock(idx);
1204 /* Test call_rcu() invocation from interrupt handler. */
1205 if (cur_ops->call) {
1206 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT);
1209 cur_ops->call(rhp, rcu_torture_timer_cb);
1214 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
1215 * incrementing the corresponding element of the pipeline array. The
1216 * counter in the element should never be greater than 1, otherwise, the
1217 * RCU implementation is broken.
1220 rcu_torture_reader(void *arg)
1222 DEFINE_TORTURE_RANDOM(rand);
1223 struct timer_list t;
1225 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
1226 set_user_nice(current, MAX_NICE);
1227 if (irqreader && cur_ops->irq_capable)
1228 timer_setup_on_stack(&t, rcu_torture_timer, 0);
1231 if (irqreader && cur_ops->irq_capable) {
1232 if (!timer_pending(&t))
1233 mod_timer(&t, jiffies + 1);
1235 if (!rcu_torture_one_read(&rand))
1236 schedule_timeout_interruptible(HZ);
1237 stutter_wait("rcu_torture_reader");
1238 } while (!torture_must_stop());
1239 if (irqreader && cur_ops->irq_capable) {
1241 destroy_timer_on_stack(&t);
1243 torture_kthread_stopping("rcu_torture_reader");
1248 * Print torture statistics. Caller must ensure that there is only
1249 * one call to this function at a given time!!! This is normally
1250 * accomplished by relying on the module system to only have one copy
1251 * of the module loaded, and then by giving the rcu_torture_stats
1252 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1253 * thread is not running).
1256 rcu_torture_stats_print(void)
1260 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1261 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1262 static unsigned long rtcv_snap = ULONG_MAX;
1263 static bool splatted;
1264 struct task_struct *wtp;
1266 for_each_possible_cpu(cpu) {
1267 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1268 pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
1269 batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
1272 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
1273 if (pipesummary[i] != 0)
1277 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1278 pr_cont("rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
1279 rcu_torture_current,
1280 rcu_torture_current_version,
1281 list_empty(&rcu_torture_freelist),
1282 atomic_read(&n_rcu_torture_alloc),
1283 atomic_read(&n_rcu_torture_alloc_fail),
1284 atomic_read(&n_rcu_torture_free));
1285 pr_cont("rtmbe: %d rtbe: %ld rtbke: %ld rtbre: %ld ",
1286 atomic_read(&n_rcu_torture_mberror),
1287 n_rcu_torture_barrier_error,
1288 n_rcu_torture_boost_ktrerror,
1289 n_rcu_torture_boost_rterror);
1290 pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
1291 n_rcu_torture_boost_failure,
1292 n_rcu_torture_boosts,
1293 atomic_long_read(&n_rcu_torture_timers));
1294 torture_onoff_stats();
1295 pr_cont("barrier: %ld/%ld:%ld ",
1296 n_barrier_successes,
1298 n_rcu_torture_barrier_error);
1299 pr_cont("cbflood: %ld\n", atomic_long_read(&n_cbfloods));
1301 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1302 if (atomic_read(&n_rcu_torture_mberror) != 0 ||
1303 n_rcu_torture_barrier_error != 0 ||
1304 n_rcu_torture_boost_ktrerror != 0 ||
1305 n_rcu_torture_boost_rterror != 0 ||
1306 n_rcu_torture_boost_failure != 0 ||
1308 pr_cont("%s", "!!! ");
1309 atomic_inc(&n_rcu_torture_error);
1312 pr_cont("Reader Pipe: ");
1313 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1314 pr_cont(" %ld", pipesummary[i]);
1317 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1318 pr_cont("Reader Batch: ");
1319 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1320 pr_cont(" %ld", batchsummary[i]);
1323 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1324 pr_cont("Free-Block Circulation: ");
1325 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1326 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
1332 if (rtcv_snap == rcu_torture_current_version &&
1333 rcu_torture_current != NULL) {
1334 int __maybe_unused flags = 0;
1335 unsigned long __maybe_unused gp_seq = 0;
1337 rcutorture_get_gp_data(cur_ops->ttype,
1339 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp,
1341 wtp = READ_ONCE(writer_task);
1342 pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#lx cpu %d\n",
1343 rcu_torture_writer_state_getname(),
1344 rcu_torture_writer_state, gp_seq, flags,
1345 wtp == NULL ? ~0UL : wtp->state,
1346 wtp == NULL ? -1 : (int)task_cpu(wtp));
1347 if (!splatted && wtp) {
1348 sched_show_task(wtp);
1351 show_rcu_gp_kthreads();
1352 rcu_ftrace_dump(DUMP_ALL);
1354 rtcv_snap = rcu_torture_current_version;
1358 * Periodically prints torture statistics, if periodic statistics printing
1359 * was specified via the stat_interval module parameter.
1362 rcu_torture_stats(void *arg)
1364 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1366 schedule_timeout_interruptible(stat_interval * HZ);
1367 rcu_torture_stats_print();
1368 torture_shutdown_absorb("rcu_torture_stats");
1369 } while (!torture_must_stop());
1370 torture_kthread_stopping("rcu_torture_stats");
1375 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1377 pr_alert("%s" TORTURE_FLAG
1378 "--- %s: nreaders=%d nfakewriters=%d "
1379 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1380 "shuffle_interval=%d stutter=%d irqreader=%d "
1381 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1382 "test_boost=%d/%d test_boost_interval=%d "
1383 "test_boost_duration=%d shutdown_secs=%d "
1384 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d "
1386 "onoff_interval=%d onoff_holdoff=%d\n",
1387 torture_type, tag, nrealreaders, nfakewriters,
1388 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1389 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1390 test_boost, cur_ops->can_boost,
1391 test_boost_interval, test_boost_duration, shutdown_secs,
1392 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff,
1394 onoff_interval, onoff_holdoff);
1397 static int rcutorture_booster_cleanup(unsigned int cpu)
1399 struct task_struct *t;
1401 if (boost_tasks[cpu] == NULL)
1403 mutex_lock(&boost_mutex);
1404 t = boost_tasks[cpu];
1405 boost_tasks[cpu] = NULL;
1406 mutex_unlock(&boost_mutex);
1408 /* This must be outside of the mutex, otherwise deadlock! */
1409 torture_stop_kthread(rcu_torture_boost, t);
1413 static int rcutorture_booster_init(unsigned int cpu)
1417 if (boost_tasks[cpu] != NULL)
1418 return 0; /* Already created, nothing more to do. */
1420 /* Don't allow time recalculation while creating a new task. */
1421 mutex_lock(&boost_mutex);
1422 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
1423 boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
1425 "rcu_torture_boost");
1426 if (IS_ERR(boost_tasks[cpu])) {
1427 retval = PTR_ERR(boost_tasks[cpu]);
1428 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
1429 n_rcu_torture_boost_ktrerror++;
1430 boost_tasks[cpu] = NULL;
1431 mutex_unlock(&boost_mutex);
1434 kthread_bind(boost_tasks[cpu], cpu);
1435 wake_up_process(boost_tasks[cpu]);
1436 mutex_unlock(&boost_mutex);
1441 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
1442 * induces a CPU stall for the time specified by stall_cpu.
1444 static int rcu_torture_stall(void *args)
1446 unsigned long stop_at;
1448 VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
1449 if (stall_cpu_holdoff > 0) {
1450 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
1451 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
1452 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
1454 if (!kthread_should_stop()) {
1455 stop_at = get_seconds() + stall_cpu;
1456 /* RCU CPU stall is expected behavior in following code. */
1458 if (stall_cpu_irqsoff)
1459 local_irq_disable();
1462 pr_alert("rcu_torture_stall start on CPU %d.\n",
1463 smp_processor_id());
1464 while (ULONG_CMP_LT(get_seconds(), stop_at))
1465 continue; /* Induce RCU CPU stall warning. */
1466 if (stall_cpu_irqsoff)
1471 pr_alert("rcu_torture_stall end.\n");
1473 torture_shutdown_absorb("rcu_torture_stall");
1474 while (!kthread_should_stop())
1475 schedule_timeout_interruptible(10 * HZ);
1479 /* Spawn CPU-stall kthread, if stall_cpu specified. */
1480 static int __init rcu_torture_stall_init(void)
1484 return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
1487 /* Callback function for RCU barrier testing. */
1488 static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
1490 atomic_inc(&barrier_cbs_invoked);
1493 /* kthread function to register callbacks used to test RCU barriers. */
1494 static int rcu_torture_barrier_cbs(void *arg)
1496 long myid = (long)arg;
1499 struct rcu_head rcu;
1501 init_rcu_head_on_stack(&rcu);
1502 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
1503 set_user_nice(current, MAX_NICE);
1505 wait_event(barrier_cbs_wq[myid],
1507 smp_load_acquire(&barrier_phase)) != lastphase ||
1508 torture_must_stop());
1509 lastphase = newphase;
1510 if (torture_must_stop())
1513 * The above smp_load_acquire() ensures barrier_phase load
1514 * is ordered before the following ->call().
1516 local_irq_disable(); /* Just to test no-irq call_rcu(). */
1517 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
1519 if (atomic_dec_and_test(&barrier_cbs_count))
1520 wake_up(&barrier_wq);
1521 } while (!torture_must_stop());
1522 if (cur_ops->cb_barrier != NULL)
1523 cur_ops->cb_barrier();
1524 destroy_rcu_head_on_stack(&rcu);
1525 torture_kthread_stopping("rcu_torture_barrier_cbs");
1529 /* kthread function to drive and coordinate RCU barrier testing. */
1530 static int rcu_torture_barrier(void *arg)
1534 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
1536 atomic_set(&barrier_cbs_invoked, 0);
1537 atomic_set(&barrier_cbs_count, n_barrier_cbs);
1538 /* Ensure barrier_phase ordered after prior assignments. */
1539 smp_store_release(&barrier_phase, !barrier_phase);
1540 for (i = 0; i < n_barrier_cbs; i++)
1541 wake_up(&barrier_cbs_wq[i]);
1542 wait_event(barrier_wq,
1543 atomic_read(&barrier_cbs_count) == 0 ||
1544 torture_must_stop());
1545 if (torture_must_stop())
1547 n_barrier_attempts++;
1548 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
1549 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
1550 n_rcu_torture_barrier_error++;
1551 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
1552 atomic_read(&barrier_cbs_invoked),
1556 n_barrier_successes++;
1557 schedule_timeout_interruptible(HZ / 10);
1558 } while (!torture_must_stop());
1559 torture_kthread_stopping("rcu_torture_barrier");
1563 /* Initialize RCU barrier testing. */
1564 static int rcu_torture_barrier_init(void)
1569 if (n_barrier_cbs <= 0)
1571 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
1572 pr_alert("%s" TORTURE_FLAG
1573 " Call or barrier ops missing for %s,\n",
1574 torture_type, cur_ops->name);
1575 pr_alert("%s" TORTURE_FLAG
1576 " RCU barrier testing omitted from run.\n",
1580 atomic_set(&barrier_cbs_count, 0);
1581 atomic_set(&barrier_cbs_invoked, 0);
1583 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]),
1586 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL);
1587 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
1589 for (i = 0; i < n_barrier_cbs; i++) {
1590 init_waitqueue_head(&barrier_cbs_wq[i]);
1591 ret = torture_create_kthread(rcu_torture_barrier_cbs,
1593 barrier_cbs_tasks[i]);
1597 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
1600 /* Clean up after RCU barrier testing. */
1601 static void rcu_torture_barrier_cleanup(void)
1605 torture_stop_kthread(rcu_torture_barrier, barrier_task);
1606 if (barrier_cbs_tasks != NULL) {
1607 for (i = 0; i < n_barrier_cbs; i++)
1608 torture_stop_kthread(rcu_torture_barrier_cbs,
1609 barrier_cbs_tasks[i]);
1610 kfree(barrier_cbs_tasks);
1611 barrier_cbs_tasks = NULL;
1613 if (barrier_cbs_wq != NULL) {
1614 kfree(barrier_cbs_wq);
1615 barrier_cbs_wq = NULL;
1619 static enum cpuhp_state rcutor_hp;
1622 rcu_torture_cleanup(void)
1625 unsigned long gp_seq = 0;
1628 if (torture_cleanup_begin()) {
1629 if (cur_ops->cb_barrier != NULL)
1630 cur_ops->cb_barrier();
1634 rcu_torture_barrier_cleanup();
1635 torture_stop_kthread(rcu_torture_stall, stall_task);
1636 torture_stop_kthread(rcu_torture_writer, writer_task);
1639 for (i = 0; i < nrealreaders; i++)
1640 torture_stop_kthread(rcu_torture_reader,
1642 kfree(reader_tasks);
1644 rcu_torture_current = NULL;
1646 if (fakewriter_tasks) {
1647 for (i = 0; i < nfakewriters; i++) {
1648 torture_stop_kthread(rcu_torture_fakewriter,
1649 fakewriter_tasks[i]);
1651 kfree(fakewriter_tasks);
1652 fakewriter_tasks = NULL;
1655 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq);
1656 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq);
1657 pr_alert("%s: End-test grace-period state: g%lu f%#x\n",
1658 cur_ops->name, gp_seq, flags);
1659 torture_stop_kthread(rcu_torture_stats, stats_task);
1660 torture_stop_kthread(rcu_torture_fqs, fqs_task);
1661 for (i = 0; i < ncbflooders; i++)
1662 torture_stop_kthread(rcu_torture_cbflood, cbflood_task[i]);
1663 if ((test_boost == 1 && cur_ops->can_boost) ||
1665 cpuhp_remove_state(rcutor_hp);
1668 * Wait for all RCU callbacks to fire, then do flavor-specific
1669 * cleanup operations.
1671 if (cur_ops->cb_barrier != NULL)
1672 cur_ops->cb_barrier();
1673 if (cur_ops->cleanup != NULL)
1676 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
1678 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
1679 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
1680 else if (torture_onoff_failures())
1681 rcu_torture_print_module_parms(cur_ops,
1682 "End of test: RCU_HOTPLUG");
1684 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
1685 torture_cleanup_end();
1688 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1689 static void rcu_torture_leak_cb(struct rcu_head *rhp)
1693 static void rcu_torture_err_cb(struct rcu_head *rhp)
1696 * This -might- happen due to race conditions, but is unlikely.
1697 * The scenario that leads to this happening is that the
1698 * first of the pair of duplicate callbacks is queued,
1699 * someone else starts a grace period that includes that
1700 * callback, then the second of the pair must wait for the
1701 * next grace period. Unlikely, but can happen. If it
1702 * does happen, the debug-objects subsystem won't have splatted.
1704 pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME);
1706 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1709 * Verify that double-free causes debug-objects to complain, but only
1710 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
1711 * cannot be carried out.
1713 static void rcu_test_debug_objects(void)
1715 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1716 struct rcu_head rh1;
1717 struct rcu_head rh2;
1719 init_rcu_head_on_stack(&rh1);
1720 init_rcu_head_on_stack(&rh2);
1721 pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME);
1723 /* Try to queue the rh2 pair of callbacks for the same grace period. */
1724 preempt_disable(); /* Prevent preemption from interrupting test. */
1725 rcu_read_lock(); /* Make it impossible to finish a grace period. */
1726 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
1727 local_irq_disable(); /* Make it harder to start a new grace period. */
1728 call_rcu(&rh2, rcu_torture_leak_cb);
1729 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
1734 /* Wait for them all to get done so we can safely return. */
1736 pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME);
1737 destroy_rcu_head_on_stack(&rh1);
1738 destroy_rcu_head_on_stack(&rh2);
1739 #else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1740 pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME);
1741 #endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1745 rcu_torture_init(void)
1750 static struct rcu_torture_ops *torture_ops[] = {
1751 &rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops,
1752 &sched_ops, &tasks_ops,
1755 if (!torture_init_begin(torture_type, verbose))
1758 /* Process args and tell the world that the torturer is on the job. */
1759 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1760 cur_ops = torture_ops[i];
1761 if (strcmp(torture_type, cur_ops->name) == 0)
1764 if (i == ARRAY_SIZE(torture_ops)) {
1765 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
1767 pr_alert("rcu-torture types:");
1768 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1769 pr_alert(" %s", torture_ops[i]->name);
1774 if (cur_ops->fqs == NULL && fqs_duration != 0) {
1775 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
1781 if (nreaders >= 0) {
1782 nrealreaders = nreaders;
1784 nrealreaders = num_online_cpus() - 2 - nreaders;
1785 if (nrealreaders <= 0)
1788 rcu_torture_print_module_parms(cur_ops, "Start of test");
1790 /* Set up the freelist. */
1792 INIT_LIST_HEAD(&rcu_torture_freelist);
1793 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1794 rcu_tortures[i].rtort_mbtest = 0;
1795 list_add_tail(&rcu_tortures[i].rtort_free,
1796 &rcu_torture_freelist);
1799 /* Initialize the statistics so that each run gets its own numbers. */
1801 rcu_torture_current = NULL;
1802 rcu_torture_current_version = 0;
1803 atomic_set(&n_rcu_torture_alloc, 0);
1804 atomic_set(&n_rcu_torture_alloc_fail, 0);
1805 atomic_set(&n_rcu_torture_free, 0);
1806 atomic_set(&n_rcu_torture_mberror, 0);
1807 atomic_set(&n_rcu_torture_error, 0);
1808 n_rcu_torture_barrier_error = 0;
1809 n_rcu_torture_boost_ktrerror = 0;
1810 n_rcu_torture_boost_rterror = 0;
1811 n_rcu_torture_boost_failure = 0;
1812 n_rcu_torture_boosts = 0;
1813 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1814 atomic_set(&rcu_torture_wcount[i], 0);
1815 for_each_possible_cpu(cpu) {
1816 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1817 per_cpu(rcu_torture_count, cpu)[i] = 0;
1818 per_cpu(rcu_torture_batch, cpu)[i] = 0;
1822 /* Start up the kthreads. */
1824 firsterr = torture_create_kthread(rcu_torture_writer, NULL,
1828 if (nfakewriters > 0) {
1829 fakewriter_tasks = kcalloc(nfakewriters,
1830 sizeof(fakewriter_tasks[0]),
1832 if (fakewriter_tasks == NULL) {
1833 VERBOSE_TOROUT_ERRSTRING("out of memory");
1838 for (i = 0; i < nfakewriters; i++) {
1839 firsterr = torture_create_kthread(rcu_torture_fakewriter,
1840 NULL, fakewriter_tasks[i]);
1844 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
1846 if (reader_tasks == NULL) {
1847 VERBOSE_TOROUT_ERRSTRING("out of memory");
1851 for (i = 0; i < nrealreaders; i++) {
1852 firsterr = torture_create_kthread(rcu_torture_reader, NULL,
1857 if (stat_interval > 0) {
1858 firsterr = torture_create_kthread(rcu_torture_stats, NULL,
1863 if (test_no_idle_hz && shuffle_interval > 0) {
1864 firsterr = torture_shuffle_init(shuffle_interval * HZ);
1871 firsterr = torture_stutter_init(stutter * HZ);
1875 if (fqs_duration < 0)
1878 /* Create the fqs thread */
1879 firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
1884 if (test_boost_interval < 1)
1885 test_boost_interval = 1;
1886 if (test_boost_duration < 2)
1887 test_boost_duration = 2;
1888 if ((test_boost == 1 && cur_ops->can_boost) ||
1891 boost_starttime = jiffies + test_boost_interval * HZ;
1893 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE",
1894 rcutorture_booster_init,
1895 rcutorture_booster_cleanup);
1898 rcutor_hp = firsterr;
1900 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
1903 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval);
1906 firsterr = rcu_torture_stall_init();
1909 firsterr = rcu_torture_barrier_init();
1913 rcu_test_debug_objects();
1914 if (cbflood_n_burst > 0) {
1915 /* Create the cbflood threads */
1916 ncbflooders = (num_online_cpus() + 3) / 4;
1917 cbflood_task = kcalloc(ncbflooders, sizeof(*cbflood_task),
1919 if (!cbflood_task) {
1920 VERBOSE_TOROUT_ERRSTRING("out of memory");
1924 for (i = 0; i < ncbflooders; i++) {
1925 firsterr = torture_create_kthread(rcu_torture_cbflood,
1937 rcu_torture_cleanup();
1941 module_init(rcu_torture_init);
1942 module_exit(rcu_torture_cleanup);