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
25 #include <linux/types.h>
26 #include <linux/kernel.h>
27 #include <linux/init.h>
28 #include <linux/module.h>
29 #include <linux/kthread.h>
30 #include <linux/err.h>
31 #include <linux/spinlock.h>
32 #include <linux/smp.h>
33 #include <linux/rcupdate.h>
34 #include <linux/interrupt.h>
35 #include <linux/sched.h>
36 #include <linux/atomic.h>
37 #include <linux/bitops.h>
38 #include <linux/completion.h>
39 #include <linux/moduleparam.h>
40 #include <linux/percpu.h>
41 #include <linux/notifier.h>
42 #include <linux/reboot.h>
43 #include <linux/freezer.h>
44 #include <linux/cpu.h>
45 #include <linux/delay.h>
46 #include <linux/stat.h>
47 #include <linux/srcu.h>
48 #include <linux/slab.h>
49 #include <linux/trace_clock.h>
50 #include <asm/byteorder.h>
51 #include <linux/torture.h>
52 #include <linux/vmalloc.h>
54 MODULE_LICENSE("GPL");
55 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
58 torture_param(int, cbflood_inter_holdoff, HZ,
59 "Holdoff between floods (jiffies)");
60 torture_param(int, cbflood_intra_holdoff, 1,
61 "Holdoff between bursts (jiffies)");
62 torture_param(int, cbflood_n_burst, 3, "# bursts in flood, zero to disable");
63 torture_param(int, cbflood_n_per_burst, 20000,
64 "# callbacks per burst in flood");
65 torture_param(int, fqs_duration, 0,
66 "Duration of fqs bursts (us), 0 to disable");
67 torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
68 torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
69 torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
70 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
71 torture_param(bool, gp_normal, false,
72 "Use normal (non-expedited) GP wait primitives");
73 torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
74 torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
75 torture_param(int, n_barrier_cbs, 0,
76 "# of callbacks/kthreads for barrier testing");
77 torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
78 torture_param(int, nreaders, -1, "Number of RCU reader threads");
79 torture_param(int, object_debug, 0,
80 "Enable debug-object double call_rcu() testing");
81 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
82 torture_param(int, onoff_interval, 0,
83 "Time between CPU hotplugs (s), 0=disable");
84 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
85 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
86 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
87 torture_param(int, stall_cpu_holdoff, 10,
88 "Time to wait before starting stall (s).");
89 torture_param(int, stat_interval, 60,
90 "Number of seconds between stats printk()s");
91 torture_param(int, stutter, 5, "Number of seconds to run/halt test");
92 torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
93 torture_param(int, test_boost_duration, 4,
94 "Duration of each boost test, seconds.");
95 torture_param(int, test_boost_interval, 7,
96 "Interval between boost tests, seconds.");
97 torture_param(bool, test_no_idle_hz, true,
98 "Test support for tickless idle CPUs");
99 torture_param(bool, verbose, true,
100 "Enable verbose debugging printk()s");
102 static char *torture_type = "rcu";
103 module_param(torture_type, charp, 0444);
104 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, ...)");
106 static int nrealreaders;
107 static int ncbflooders;
108 static struct task_struct *writer_task;
109 static struct task_struct **fakewriter_tasks;
110 static struct task_struct **reader_tasks;
111 static struct task_struct *stats_task;
112 static struct task_struct **cbflood_task;
113 static struct task_struct *fqs_task;
114 static struct task_struct *boost_tasks[NR_CPUS];
115 static struct task_struct *stall_task;
116 static struct task_struct **barrier_cbs_tasks;
117 static struct task_struct *barrier_task;
119 #define RCU_TORTURE_PIPE_LEN 10
122 struct rcu_head rtort_rcu;
123 int rtort_pipe_count;
124 struct list_head rtort_free;
128 static LIST_HEAD(rcu_torture_freelist);
129 static struct rcu_torture __rcu *rcu_torture_current;
130 static unsigned long rcu_torture_current_version;
131 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
132 static DEFINE_SPINLOCK(rcu_torture_lock);
133 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1],
134 rcu_torture_count) = { 0 };
135 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1],
136 rcu_torture_batch) = { 0 };
137 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
138 static atomic_t n_rcu_torture_alloc;
139 static atomic_t n_rcu_torture_alloc_fail;
140 static atomic_t n_rcu_torture_free;
141 static atomic_t n_rcu_torture_mberror;
142 static atomic_t n_rcu_torture_error;
143 static long n_rcu_torture_barrier_error;
144 static long n_rcu_torture_boost_ktrerror;
145 static long n_rcu_torture_boost_rterror;
146 static long n_rcu_torture_boost_failure;
147 static long n_rcu_torture_boosts;
148 static long n_rcu_torture_timers;
149 static long n_barrier_attempts;
150 static long n_barrier_successes;
151 static atomic_long_t n_cbfloods;
152 static struct list_head rcu_torture_removed;
154 static int rcu_torture_writer_state;
155 #define RTWS_FIXED_DELAY 0
157 #define RTWS_REPLACE 2
158 #define RTWS_DEF_FREE 3
159 #define RTWS_EXP_SYNC 4
160 #define RTWS_COND_GET 5
161 #define RTWS_COND_SYNC 6
163 #define RTWS_STUTTER 8
164 #define RTWS_STOPPING 9
165 static const char * const rcu_torture_writer_state_names[] = {
178 static const char *rcu_torture_writer_state_getname(void)
180 unsigned int i = READ_ONCE(rcu_torture_writer_state);
182 if (i >= ARRAY_SIZE(rcu_torture_writer_state_names))
184 return rcu_torture_writer_state_names[i];
187 #if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
188 #define RCUTORTURE_RUNNABLE_INIT 1
190 #define RCUTORTURE_RUNNABLE_INIT 0
192 static int torture_runnable = RCUTORTURE_RUNNABLE_INIT;
193 module_param(torture_runnable, int, 0444);
194 MODULE_PARM_DESC(torture_runnable, "Start rcutorture at boot");
196 #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
197 #define rcu_can_boost() 1
198 #else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
199 #define rcu_can_boost() 0
200 #endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
202 #ifdef CONFIG_RCU_TRACE
203 static u64 notrace rcu_trace_clock_local(void)
205 u64 ts = trace_clock_local();
206 unsigned long __maybe_unused ts_rem = do_div(ts, NSEC_PER_USEC);
209 #else /* #ifdef CONFIG_RCU_TRACE */
210 static u64 notrace rcu_trace_clock_local(void)
214 #endif /* #else #ifdef CONFIG_RCU_TRACE */
216 static unsigned long boost_starttime; /* jiffies of next boost test start. */
217 static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
218 /* and boost task create/destroy. */
219 static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
220 static bool barrier_phase; /* Test phase. */
221 static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
222 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
223 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
226 * Allocate an element from the rcu_tortures pool.
228 static struct rcu_torture *
229 rcu_torture_alloc(void)
233 spin_lock_bh(&rcu_torture_lock);
234 if (list_empty(&rcu_torture_freelist)) {
235 atomic_inc(&n_rcu_torture_alloc_fail);
236 spin_unlock_bh(&rcu_torture_lock);
239 atomic_inc(&n_rcu_torture_alloc);
240 p = rcu_torture_freelist.next;
242 spin_unlock_bh(&rcu_torture_lock);
243 return container_of(p, struct rcu_torture, rtort_free);
247 * Free an element to the rcu_tortures pool.
250 rcu_torture_free(struct rcu_torture *p)
252 atomic_inc(&n_rcu_torture_free);
253 spin_lock_bh(&rcu_torture_lock);
254 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
255 spin_unlock_bh(&rcu_torture_lock);
259 * Operations vector for selecting different types of tests.
262 struct rcu_torture_ops {
265 void (*cleanup)(void);
266 int (*readlock)(void);
267 void (*read_delay)(struct torture_random_state *rrsp);
268 void (*readunlock)(int idx);
269 unsigned long (*started)(void);
270 unsigned long (*completed)(void);
271 void (*deferred_free)(struct rcu_torture *p);
273 void (*exp_sync)(void);
274 unsigned long (*get_state)(void);
275 void (*cond_sync)(unsigned long oldstate);
276 call_rcu_func_t call;
277 void (*cb_barrier)(void);
285 static struct rcu_torture_ops *cur_ops;
288 * Definitions for rcu torture testing.
291 static int rcu_torture_read_lock(void) __acquires(RCU)
297 static void rcu_read_delay(struct torture_random_state *rrsp)
299 const unsigned long shortdelay_us = 200;
300 const unsigned long longdelay_ms = 50;
302 /* We want a short delay sometimes to make a reader delay the grace
303 * period, and we want a long delay occasionally to trigger
304 * force_quiescent_state. */
306 if (!(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms)))
307 mdelay(longdelay_ms);
308 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
309 udelay(shortdelay_us);
310 #ifdef CONFIG_PREEMPT
311 if (!preempt_count() &&
312 !(torture_random(rrsp) % (nrealreaders * 20000)))
313 preempt_schedule(); /* No QS if preempt_disable() in effect */
317 static void rcu_torture_read_unlock(int idx) __releases(RCU)
323 * Update callback in the pipe. This should be invoked after a grace period.
326 rcu_torture_pipe_update_one(struct rcu_torture *rp)
330 i = rp->rtort_pipe_count;
331 if (i > RCU_TORTURE_PIPE_LEN)
332 i = RCU_TORTURE_PIPE_LEN;
333 atomic_inc(&rcu_torture_wcount[i]);
334 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
335 rp->rtort_mbtest = 0;
342 * Update all callbacks in the pipe. Suitable for synchronous grace-period
346 rcu_torture_pipe_update(struct rcu_torture *old_rp)
348 struct rcu_torture *rp;
349 struct rcu_torture *rp1;
352 list_add(&old_rp->rtort_free, &rcu_torture_removed);
353 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
354 if (rcu_torture_pipe_update_one(rp)) {
355 list_del(&rp->rtort_free);
356 rcu_torture_free(rp);
362 rcu_torture_cb(struct rcu_head *p)
364 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
366 if (torture_must_stop_irq()) {
367 /* Test is ending, just drop callbacks on the floor. */
368 /* The next initialization will pick up the pieces. */
371 if (rcu_torture_pipe_update_one(rp))
372 rcu_torture_free(rp);
374 cur_ops->deferred_free(rp);
377 static unsigned long rcu_no_completed(void)
382 static void rcu_torture_deferred_free(struct rcu_torture *p)
384 call_rcu(&p->rtort_rcu, rcu_torture_cb);
387 static void rcu_sync_torture_init(void)
389 INIT_LIST_HEAD(&rcu_torture_removed);
392 static struct rcu_torture_ops rcu_ops = {
394 .init = rcu_sync_torture_init,
395 .readlock = rcu_torture_read_lock,
396 .read_delay = rcu_read_delay,
397 .readunlock = rcu_torture_read_unlock,
398 .started = rcu_batches_started,
399 .completed = rcu_batches_completed,
400 .deferred_free = rcu_torture_deferred_free,
401 .sync = synchronize_rcu,
402 .exp_sync = synchronize_rcu_expedited,
403 .get_state = get_state_synchronize_rcu,
404 .cond_sync = cond_synchronize_rcu,
406 .cb_barrier = rcu_barrier,
407 .fqs = rcu_force_quiescent_state,
410 .can_boost = rcu_can_boost(),
415 * Definitions for rcu_bh torture testing.
418 static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
424 static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
426 rcu_read_unlock_bh();
429 static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
431 call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
434 static struct rcu_torture_ops rcu_bh_ops = {
435 .ttype = RCU_BH_FLAVOR,
436 .init = rcu_sync_torture_init,
437 .readlock = rcu_bh_torture_read_lock,
438 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
439 .readunlock = rcu_bh_torture_read_unlock,
440 .started = rcu_batches_started_bh,
441 .completed = rcu_batches_completed_bh,
442 .deferred_free = rcu_bh_torture_deferred_free,
443 .sync = synchronize_rcu_bh,
444 .exp_sync = synchronize_rcu_bh_expedited,
446 .cb_barrier = rcu_barrier_bh,
447 .fqs = rcu_bh_force_quiescent_state,
454 * Don't even think about trying any of these in real life!!!
455 * The names includes "busted", and they really means it!
456 * The only purpose of these functions is to provide a buggy RCU
457 * implementation to make sure that rcutorture correctly emits
458 * buggy-RCU error messages.
460 static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
462 /* This is a deliberate bug for testing purposes only! */
463 rcu_torture_cb(&p->rtort_rcu);
466 static void synchronize_rcu_busted(void)
468 /* This is a deliberate bug for testing purposes only! */
472 call_rcu_busted(struct rcu_head *head, rcu_callback_t func)
474 /* This is a deliberate bug for testing purposes only! */
478 static struct rcu_torture_ops rcu_busted_ops = {
479 .ttype = INVALID_RCU_FLAVOR,
480 .init = rcu_sync_torture_init,
481 .readlock = rcu_torture_read_lock,
482 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
483 .readunlock = rcu_torture_read_unlock,
484 .started = rcu_no_completed,
485 .completed = rcu_no_completed,
486 .deferred_free = rcu_busted_torture_deferred_free,
487 .sync = synchronize_rcu_busted,
488 .exp_sync = synchronize_rcu_busted,
489 .call = call_rcu_busted,
498 * Definitions for srcu torture testing.
501 DEFINE_STATIC_SRCU(srcu_ctl);
502 static struct srcu_struct srcu_ctld;
503 static struct srcu_struct *srcu_ctlp = &srcu_ctl;
505 static int srcu_torture_read_lock(void) __acquires(srcu_ctlp)
507 return srcu_read_lock(srcu_ctlp);
510 static void srcu_read_delay(struct torture_random_state *rrsp)
513 const long uspertick = 1000000 / HZ;
514 const long longdelay = 10;
516 /* We want there to be long-running readers, but not all the time. */
518 delay = torture_random(rrsp) %
519 (nrealreaders * 2 * longdelay * uspertick);
521 schedule_timeout_interruptible(longdelay);
523 rcu_read_delay(rrsp);
526 static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp)
528 srcu_read_unlock(srcu_ctlp, idx);
531 static unsigned long srcu_torture_completed(void)
533 return srcu_batches_completed(srcu_ctlp);
536 static void srcu_torture_deferred_free(struct rcu_torture *rp)
538 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
541 static void srcu_torture_synchronize(void)
543 synchronize_srcu(srcu_ctlp);
546 static void srcu_torture_call(struct rcu_head *head,
549 call_srcu(srcu_ctlp, head, func);
552 static void srcu_torture_barrier(void)
554 srcu_barrier(srcu_ctlp);
557 static void srcu_torture_stats(void)
560 int idx = srcu_ctlp->completed & 0x1;
562 pr_alert("%s%s per-CPU(idx=%d):",
563 torture_type, TORTURE_FLAG, idx);
564 for_each_possible_cpu(cpu) {
567 c0 = (long)per_cpu_ptr(srcu_ctlp->per_cpu_ref, cpu)->c[!idx];
568 c1 = (long)per_cpu_ptr(srcu_ctlp->per_cpu_ref, cpu)->c[idx];
569 pr_cont(" %d(%ld,%ld)", cpu, c0, c1);
574 static void srcu_torture_synchronize_expedited(void)
576 synchronize_srcu_expedited(srcu_ctlp);
579 static struct rcu_torture_ops srcu_ops = {
580 .ttype = SRCU_FLAVOR,
581 .init = rcu_sync_torture_init,
582 .readlock = srcu_torture_read_lock,
583 .read_delay = srcu_read_delay,
584 .readunlock = srcu_torture_read_unlock,
586 .completed = srcu_torture_completed,
587 .deferred_free = srcu_torture_deferred_free,
588 .sync = srcu_torture_synchronize,
589 .exp_sync = srcu_torture_synchronize_expedited,
590 .call = srcu_torture_call,
591 .cb_barrier = srcu_torture_barrier,
592 .stats = srcu_torture_stats,
596 static void srcu_torture_init(void)
598 rcu_sync_torture_init();
599 WARN_ON(init_srcu_struct(&srcu_ctld));
600 srcu_ctlp = &srcu_ctld;
603 static void srcu_torture_cleanup(void)
605 cleanup_srcu_struct(&srcu_ctld);
606 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
609 /* As above, but dynamically allocated. */
610 static struct rcu_torture_ops srcud_ops = {
611 .ttype = SRCU_FLAVOR,
612 .init = srcu_torture_init,
613 .cleanup = srcu_torture_cleanup,
614 .readlock = srcu_torture_read_lock,
615 .read_delay = srcu_read_delay,
616 .readunlock = srcu_torture_read_unlock,
618 .completed = srcu_torture_completed,
619 .deferred_free = srcu_torture_deferred_free,
620 .sync = srcu_torture_synchronize,
621 .exp_sync = srcu_torture_synchronize_expedited,
622 .call = srcu_torture_call,
623 .cb_barrier = srcu_torture_barrier,
624 .stats = srcu_torture_stats,
629 * Definitions for sched torture testing.
632 static int sched_torture_read_lock(void)
638 static void sched_torture_read_unlock(int idx)
643 static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
645 call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
648 static struct rcu_torture_ops sched_ops = {
649 .ttype = RCU_SCHED_FLAVOR,
650 .init = rcu_sync_torture_init,
651 .readlock = sched_torture_read_lock,
652 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
653 .readunlock = sched_torture_read_unlock,
654 .started = rcu_batches_started_sched,
655 .completed = rcu_batches_completed_sched,
656 .deferred_free = rcu_sched_torture_deferred_free,
657 .sync = synchronize_sched,
658 .exp_sync = synchronize_sched_expedited,
659 .get_state = get_state_synchronize_sched,
660 .cond_sync = cond_synchronize_sched,
661 .call = call_rcu_sched,
662 .cb_barrier = rcu_barrier_sched,
663 .fqs = rcu_sched_force_quiescent_state,
669 #ifdef CONFIG_TASKS_RCU
672 * Definitions for RCU-tasks torture testing.
675 static int tasks_torture_read_lock(void)
680 static void tasks_torture_read_unlock(int idx)
684 static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
686 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
689 static struct rcu_torture_ops tasks_ops = {
690 .ttype = RCU_TASKS_FLAVOR,
691 .init = rcu_sync_torture_init,
692 .readlock = tasks_torture_read_lock,
693 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
694 .readunlock = tasks_torture_read_unlock,
695 .started = rcu_no_completed,
696 .completed = rcu_no_completed,
697 .deferred_free = rcu_tasks_torture_deferred_free,
698 .sync = synchronize_rcu_tasks,
699 .exp_sync = synchronize_rcu_tasks,
700 .call = call_rcu_tasks,
701 .cb_barrier = rcu_barrier_tasks,
708 #define RCUTORTURE_TASKS_OPS &tasks_ops,
710 static bool __maybe_unused torturing_tasks(void)
712 return cur_ops == &tasks_ops;
715 #else /* #ifdef CONFIG_TASKS_RCU */
717 #define RCUTORTURE_TASKS_OPS
719 static bool __maybe_unused torturing_tasks(void)
724 #endif /* #else #ifdef CONFIG_TASKS_RCU */
727 * RCU torture priority-boost testing. Runs one real-time thread per
728 * CPU for moderate bursts, repeatedly registering RCU callbacks and
729 * spinning waiting for them to be invoked. If a given callback takes
730 * too long to be invoked, we assume that priority inversion has occurred.
733 struct rcu_boost_inflight {
738 static void rcu_torture_boost_cb(struct rcu_head *head)
740 struct rcu_boost_inflight *rbip =
741 container_of(head, struct rcu_boost_inflight, rcu);
743 /* Ensure RCU-core accesses precede clearing ->inflight */
744 smp_store_release(&rbip->inflight, 0);
747 static int rcu_torture_boost(void *arg)
749 unsigned long call_rcu_time;
750 unsigned long endtime;
751 unsigned long oldstarttime;
752 struct rcu_boost_inflight rbi = { .inflight = 0 };
753 struct sched_param sp;
755 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
757 /* Set real-time priority. */
758 sp.sched_priority = 1;
759 if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
760 VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!");
761 n_rcu_torture_boost_rterror++;
764 init_rcu_head_on_stack(&rbi.rcu);
765 /* Each pass through the following loop does one boost-test cycle. */
767 /* Wait for the next test interval. */
768 oldstarttime = boost_starttime;
769 while (ULONG_CMP_LT(jiffies, oldstarttime)) {
770 schedule_timeout_interruptible(oldstarttime - jiffies);
771 stutter_wait("rcu_torture_boost");
772 if (torture_must_stop())
776 /* Do one boost-test interval. */
777 endtime = oldstarttime + test_boost_duration * HZ;
778 call_rcu_time = jiffies;
779 while (ULONG_CMP_LT(jiffies, endtime)) {
780 /* If we don't have a callback in flight, post one. */
781 if (!smp_load_acquire(&rbi.inflight)) {
782 /* RCU core before ->inflight = 1. */
783 smp_store_release(&rbi.inflight, 1);
784 call_rcu(&rbi.rcu, rcu_torture_boost_cb);
785 if (jiffies - call_rcu_time >
786 test_boost_duration * HZ - HZ / 2) {
787 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
788 n_rcu_torture_boost_failure++;
790 call_rcu_time = jiffies;
792 stutter_wait("rcu_torture_boost");
793 if (torture_must_stop())
798 * Set the start time of the next test interval.
799 * Yes, this is vulnerable to long delays, but such
800 * delays simply cause a false negative for the next
801 * interval. Besides, we are running at RT priority,
802 * so delays should be relatively rare.
804 while (oldstarttime == boost_starttime &&
805 !kthread_should_stop()) {
806 if (mutex_trylock(&boost_mutex)) {
807 boost_starttime = jiffies +
808 test_boost_interval * HZ;
809 n_rcu_torture_boosts++;
810 mutex_unlock(&boost_mutex);
813 schedule_timeout_uninterruptible(1);
816 /* Go do the stutter. */
817 checkwait: stutter_wait("rcu_torture_boost");
818 } while (!torture_must_stop());
820 /* Clean up and exit. */
821 while (!kthread_should_stop() || smp_load_acquire(&rbi.inflight)) {
822 torture_shutdown_absorb("rcu_torture_boost");
823 schedule_timeout_uninterruptible(1);
825 destroy_rcu_head_on_stack(&rbi.rcu);
826 torture_kthread_stopping("rcu_torture_boost");
830 static void rcu_torture_cbflood_cb(struct rcu_head *rhp)
835 * RCU torture callback-flood kthread. Repeatedly induces bursts of calls
836 * to call_rcu() or analogous, increasing the probability of occurrence
837 * of callback-overflow corner cases.
840 rcu_torture_cbflood(void *arg)
845 struct rcu_head *rhp;
847 if (cbflood_n_per_burst > 0 &&
848 cbflood_inter_holdoff > 0 &&
849 cbflood_intra_holdoff > 0 &&
851 cur_ops->cb_barrier) {
852 rhp = vmalloc(sizeof(*rhp) *
853 cbflood_n_burst * cbflood_n_per_burst);
857 VERBOSE_TOROUT_STRING("rcu_torture_cbflood disabled: Bad args or OOM");
860 VERBOSE_TOROUT_STRING("rcu_torture_cbflood task started");
862 schedule_timeout_interruptible(cbflood_inter_holdoff);
863 atomic_long_inc(&n_cbfloods);
864 WARN_ON(signal_pending(current));
865 for (i = 0; i < cbflood_n_burst; i++) {
866 for (j = 0; j < cbflood_n_per_burst; j++) {
867 cur_ops->call(&rhp[i * cbflood_n_per_burst + j],
868 rcu_torture_cbflood_cb);
870 schedule_timeout_interruptible(cbflood_intra_holdoff);
871 WARN_ON(signal_pending(current));
873 cur_ops->cb_barrier();
874 stutter_wait("rcu_torture_cbflood");
875 } while (!torture_must_stop());
878 torture_kthread_stopping("rcu_torture_cbflood");
883 * RCU torture force-quiescent-state kthread. Repeatedly induces
884 * bursts of calls to force_quiescent_state(), increasing the probability
885 * of occurrence of some important types of race conditions.
888 rcu_torture_fqs(void *arg)
890 unsigned long fqs_resume_time;
891 int fqs_burst_remaining;
893 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
895 fqs_resume_time = jiffies + fqs_stutter * HZ;
896 while (ULONG_CMP_LT(jiffies, fqs_resume_time) &&
897 !kthread_should_stop()) {
898 schedule_timeout_interruptible(1);
900 fqs_burst_remaining = fqs_duration;
901 while (fqs_burst_remaining > 0 &&
902 !kthread_should_stop()) {
905 fqs_burst_remaining -= fqs_holdoff;
907 stutter_wait("rcu_torture_fqs");
908 } while (!torture_must_stop());
909 torture_kthread_stopping("rcu_torture_fqs");
914 * RCU torture writer kthread. Repeatedly substitutes a new structure
915 * for that pointed to by rcu_torture_current, freeing the old structure
916 * after a series of grace periods (the "pipeline").
919 rcu_torture_writer(void *arg)
921 bool can_expedite = !rcu_gp_is_expedited();
923 unsigned long gp_snap;
924 bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal;
925 bool gp_sync1 = gp_sync;
927 struct rcu_torture *rp;
928 struct rcu_torture *old_rp;
929 static DEFINE_TORTURE_RANDOM(rand);
930 int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC,
931 RTWS_COND_GET, RTWS_SYNC };
934 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
936 pr_alert("%s" TORTURE_FLAG
937 " Grace periods expedited from boot/sysfs for %s,\n",
938 torture_type, cur_ops->name);
939 pr_alert("%s" TORTURE_FLAG
940 " Disabled dynamic grace-period expediting.\n",
944 /* Initialize synctype[] array. If none set, take default. */
945 if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync1)
946 gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true;
947 if (gp_cond1 && cur_ops->get_state && cur_ops->cond_sync)
948 synctype[nsynctypes++] = RTWS_COND_GET;
949 else if (gp_cond && (!cur_ops->get_state || !cur_ops->cond_sync))
950 pr_alert("rcu_torture_writer: gp_cond without primitives.\n");
951 if (gp_exp1 && cur_ops->exp_sync)
952 synctype[nsynctypes++] = RTWS_EXP_SYNC;
953 else if (gp_exp && !cur_ops->exp_sync)
954 pr_alert("rcu_torture_writer: gp_exp without primitives.\n");
955 if (gp_normal1 && cur_ops->deferred_free)
956 synctype[nsynctypes++] = RTWS_DEF_FREE;
957 else if (gp_normal && !cur_ops->deferred_free)
958 pr_alert("rcu_torture_writer: gp_normal without primitives.\n");
959 if (gp_sync1 && cur_ops->sync)
960 synctype[nsynctypes++] = RTWS_SYNC;
961 else if (gp_sync && !cur_ops->sync)
962 pr_alert("rcu_torture_writer: gp_sync without primitives.\n");
963 if (WARN_ONCE(nsynctypes == 0,
964 "rcu_torture_writer: No update-side primitives.\n")) {
966 * No updates primitives, so don't try updating.
967 * The resulting test won't be testing much, hence the
970 rcu_torture_writer_state = RTWS_STOPPING;
971 torture_kthread_stopping("rcu_torture_writer");
975 rcu_torture_writer_state = RTWS_FIXED_DELAY;
976 schedule_timeout_uninterruptible(1);
977 rp = rcu_torture_alloc();
980 rp->rtort_pipe_count = 0;
981 rcu_torture_writer_state = RTWS_DELAY;
982 udelay(torture_random(&rand) & 0x3ff);
983 rcu_torture_writer_state = RTWS_REPLACE;
984 old_rp = rcu_dereference_check(rcu_torture_current,
985 current == writer_task);
986 rp->rtort_mbtest = 1;
987 rcu_assign_pointer(rcu_torture_current, rp);
988 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
990 i = old_rp->rtort_pipe_count;
991 if (i > RCU_TORTURE_PIPE_LEN)
992 i = RCU_TORTURE_PIPE_LEN;
993 atomic_inc(&rcu_torture_wcount[i]);
994 old_rp->rtort_pipe_count++;
995 switch (synctype[torture_random(&rand) % nsynctypes]) {
997 rcu_torture_writer_state = RTWS_DEF_FREE;
998 cur_ops->deferred_free(old_rp);
1001 rcu_torture_writer_state = RTWS_EXP_SYNC;
1002 cur_ops->exp_sync();
1003 rcu_torture_pipe_update(old_rp);
1006 rcu_torture_writer_state = RTWS_COND_GET;
1007 gp_snap = cur_ops->get_state();
1008 i = torture_random(&rand) % 16;
1010 schedule_timeout_interruptible(i);
1011 udelay(torture_random(&rand) % 1000);
1012 rcu_torture_writer_state = RTWS_COND_SYNC;
1013 cur_ops->cond_sync(gp_snap);
1014 rcu_torture_pipe_update(old_rp);
1017 rcu_torture_writer_state = RTWS_SYNC;
1019 rcu_torture_pipe_update(old_rp);
1026 rcutorture_record_progress(++rcu_torture_current_version);
1027 /* Cycle through nesting levels of rcu_expedite_gp() calls. */
1029 !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
1030 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
1031 if (expediting >= 0)
1034 rcu_unexpedite_gp();
1035 if (++expediting > 3)
1036 expediting = -expediting;
1038 rcu_torture_writer_state = RTWS_STUTTER;
1039 stutter_wait("rcu_torture_writer");
1040 } while (!torture_must_stop());
1041 /* Reset expediting back to unexpedited. */
1043 expediting = -expediting;
1044 while (can_expedite && expediting++ < 0)
1045 rcu_unexpedite_gp();
1046 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
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 (torture_random(&rand) & 0x80)
1074 cur_ops->exp_sync();
1075 } else if (gp_normal) {
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 rcutorture_trace_dump(void)
1089 static atomic_t beenhere = ATOMIC_INIT(0);
1091 if (atomic_read(&beenhere))
1093 if (atomic_xchg(&beenhere, 1) != 0)
1095 ftrace_dump(DUMP_ALL);
1099 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
1100 * incrementing the corresponding element of the pipeline array. The
1101 * counter in the element should never be greater than 1, otherwise, the
1102 * RCU implementation is broken.
1104 static void rcu_torture_timer(unsigned long unused)
1107 unsigned long started;
1108 unsigned long completed;
1109 static DEFINE_TORTURE_RANDOM(rand);
1110 static DEFINE_SPINLOCK(rand_lock);
1111 struct rcu_torture *p;
1113 unsigned long long ts;
1115 idx = cur_ops->readlock();
1116 if (cur_ops->started)
1117 started = cur_ops->started();
1119 started = cur_ops->completed();
1120 ts = rcu_trace_clock_local();
1121 p = rcu_dereference_check(rcu_torture_current,
1122 rcu_read_lock_bh_held() ||
1123 rcu_read_lock_sched_held() ||
1124 srcu_read_lock_held(srcu_ctlp) ||
1127 /* Leave because rcu_torture_writer is not yet underway */
1128 cur_ops->readunlock(idx);
1131 if (p->rtort_mbtest == 0)
1132 atomic_inc(&n_rcu_torture_mberror);
1133 spin_lock(&rand_lock);
1134 cur_ops->read_delay(&rand);
1135 n_rcu_torture_timers++;
1136 spin_unlock(&rand_lock);
1138 pipe_count = p->rtort_pipe_count;
1139 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1140 /* Should not happen, but... */
1141 pipe_count = RCU_TORTURE_PIPE_LEN;
1143 completed = cur_ops->completed();
1144 if (pipe_count > 1) {
1145 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, ts,
1146 started, completed);
1147 rcutorture_trace_dump();
1149 __this_cpu_inc(rcu_torture_count[pipe_count]);
1150 completed = completed - started;
1151 if (cur_ops->started)
1153 if (completed > RCU_TORTURE_PIPE_LEN) {
1154 /* Should not happen, but... */
1155 completed = RCU_TORTURE_PIPE_LEN;
1157 __this_cpu_inc(rcu_torture_batch[completed]);
1159 cur_ops->readunlock(idx);
1163 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
1164 * incrementing the corresponding element of the pipeline array. The
1165 * counter in the element should never be greater than 1, otherwise, the
1166 * RCU implementation is broken.
1169 rcu_torture_reader(void *arg)
1171 unsigned long started;
1172 unsigned long completed;
1174 DEFINE_TORTURE_RANDOM(rand);
1175 struct rcu_torture *p;
1177 struct timer_list t;
1178 unsigned long long ts;
1180 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
1181 set_user_nice(current, MAX_NICE);
1182 if (irqreader && cur_ops->irq_capable)
1183 setup_timer_on_stack(&t, rcu_torture_timer, 0);
1186 if (irqreader && cur_ops->irq_capable) {
1187 if (!timer_pending(&t))
1188 mod_timer(&t, jiffies + 1);
1190 idx = cur_ops->readlock();
1191 if (cur_ops->started)
1192 started = cur_ops->started();
1194 started = cur_ops->completed();
1195 ts = rcu_trace_clock_local();
1196 p = rcu_dereference_check(rcu_torture_current,
1197 rcu_read_lock_bh_held() ||
1198 rcu_read_lock_sched_held() ||
1199 srcu_read_lock_held(srcu_ctlp) ||
1202 /* Wait for rcu_torture_writer to get underway */
1203 cur_ops->readunlock(idx);
1204 schedule_timeout_interruptible(HZ);
1207 if (p->rtort_mbtest == 0)
1208 atomic_inc(&n_rcu_torture_mberror);
1209 cur_ops->read_delay(&rand);
1211 pipe_count = p->rtort_pipe_count;
1212 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1213 /* Should not happen, but... */
1214 pipe_count = RCU_TORTURE_PIPE_LEN;
1216 completed = cur_ops->completed();
1217 if (pipe_count > 1) {
1218 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
1219 ts, started, completed);
1220 rcutorture_trace_dump();
1222 __this_cpu_inc(rcu_torture_count[pipe_count]);
1223 completed = completed - started;
1224 if (cur_ops->started)
1226 if (completed > RCU_TORTURE_PIPE_LEN) {
1227 /* Should not happen, but... */
1228 completed = RCU_TORTURE_PIPE_LEN;
1230 __this_cpu_inc(rcu_torture_batch[completed]);
1232 cur_ops->readunlock(idx);
1233 stutter_wait("rcu_torture_reader");
1234 } while (!torture_must_stop());
1235 if (irqreader && cur_ops->irq_capable) {
1237 destroy_timer_on_stack(&t);
1239 torture_kthread_stopping("rcu_torture_reader");
1244 * Print torture statistics. Caller must ensure that there is only
1245 * one call to this function at a given time!!! This is normally
1246 * accomplished by relying on the module system to only have one copy
1247 * of the module loaded, and then by giving the rcu_torture_stats
1248 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1249 * thread is not running).
1252 rcu_torture_stats_print(void)
1256 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1257 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1258 static unsigned long rtcv_snap = ULONG_MAX;
1260 for_each_possible_cpu(cpu) {
1261 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1262 pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
1263 batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
1266 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
1267 if (pipesummary[i] != 0)
1271 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1272 pr_cont("rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
1273 rcu_torture_current,
1274 rcu_torture_current_version,
1275 list_empty(&rcu_torture_freelist),
1276 atomic_read(&n_rcu_torture_alloc),
1277 atomic_read(&n_rcu_torture_alloc_fail),
1278 atomic_read(&n_rcu_torture_free));
1279 pr_cont("rtmbe: %d rtbke: %ld rtbre: %ld ",
1280 atomic_read(&n_rcu_torture_mberror),
1281 n_rcu_torture_boost_ktrerror,
1282 n_rcu_torture_boost_rterror);
1283 pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
1284 n_rcu_torture_boost_failure,
1285 n_rcu_torture_boosts,
1286 n_rcu_torture_timers);
1287 torture_onoff_stats();
1288 pr_cont("barrier: %ld/%ld:%ld ",
1289 n_barrier_successes,
1291 n_rcu_torture_barrier_error);
1292 pr_cont("cbflood: %ld\n", atomic_long_read(&n_cbfloods));
1294 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1295 if (atomic_read(&n_rcu_torture_mberror) != 0 ||
1296 n_rcu_torture_barrier_error != 0 ||
1297 n_rcu_torture_boost_ktrerror != 0 ||
1298 n_rcu_torture_boost_rterror != 0 ||
1299 n_rcu_torture_boost_failure != 0 ||
1301 pr_cont("%s", "!!! ");
1302 atomic_inc(&n_rcu_torture_error);
1305 pr_cont("Reader Pipe: ");
1306 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1307 pr_cont(" %ld", pipesummary[i]);
1310 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1311 pr_cont("Reader Batch: ");
1312 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1313 pr_cont(" %ld", batchsummary[i]);
1316 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1317 pr_cont("Free-Block Circulation: ");
1318 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1319 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
1325 if (rtcv_snap == rcu_torture_current_version &&
1326 rcu_torture_current != NULL) {
1327 int __maybe_unused flags;
1328 unsigned long __maybe_unused gpnum;
1329 unsigned long __maybe_unused completed;
1331 rcutorture_get_gp_data(cur_ops->ttype,
1332 &flags, &gpnum, &completed);
1333 pr_alert("??? Writer stall state %s(%d) g%lu c%lu f%#x\n",
1334 rcu_torture_writer_state_getname(),
1335 rcu_torture_writer_state,
1336 gpnum, completed, flags);
1337 show_rcu_gp_kthreads();
1338 rcutorture_trace_dump();
1340 rtcv_snap = rcu_torture_current_version;
1344 * Periodically prints torture statistics, if periodic statistics printing
1345 * was specified via the stat_interval module parameter.
1348 rcu_torture_stats(void *arg)
1350 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1352 schedule_timeout_interruptible(stat_interval * HZ);
1353 rcu_torture_stats_print();
1354 torture_shutdown_absorb("rcu_torture_stats");
1355 } while (!torture_must_stop());
1356 torture_kthread_stopping("rcu_torture_stats");
1361 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1363 pr_alert("%s" TORTURE_FLAG
1364 "--- %s: nreaders=%d nfakewriters=%d "
1365 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1366 "shuffle_interval=%d stutter=%d irqreader=%d "
1367 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1368 "test_boost=%d/%d test_boost_interval=%d "
1369 "test_boost_duration=%d shutdown_secs=%d "
1370 "stall_cpu=%d stall_cpu_holdoff=%d "
1372 "onoff_interval=%d onoff_holdoff=%d\n",
1373 torture_type, tag, nrealreaders, nfakewriters,
1374 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1375 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1376 test_boost, cur_ops->can_boost,
1377 test_boost_interval, test_boost_duration, shutdown_secs,
1378 stall_cpu, stall_cpu_holdoff,
1380 onoff_interval, onoff_holdoff);
1383 static void rcutorture_booster_cleanup(int cpu)
1385 struct task_struct *t;
1387 if (boost_tasks[cpu] == NULL)
1389 mutex_lock(&boost_mutex);
1390 t = boost_tasks[cpu];
1391 boost_tasks[cpu] = NULL;
1392 mutex_unlock(&boost_mutex);
1394 /* This must be outside of the mutex, otherwise deadlock! */
1395 torture_stop_kthread(rcu_torture_boost, t);
1398 static int rcutorture_booster_init(int cpu)
1402 if (boost_tasks[cpu] != NULL)
1403 return 0; /* Already created, nothing more to do. */
1405 /* Don't allow time recalculation while creating a new task. */
1406 mutex_lock(&boost_mutex);
1407 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
1408 boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
1410 "rcu_torture_boost");
1411 if (IS_ERR(boost_tasks[cpu])) {
1412 retval = PTR_ERR(boost_tasks[cpu]);
1413 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
1414 n_rcu_torture_boost_ktrerror++;
1415 boost_tasks[cpu] = NULL;
1416 mutex_unlock(&boost_mutex);
1419 kthread_bind(boost_tasks[cpu], cpu);
1420 wake_up_process(boost_tasks[cpu]);
1421 mutex_unlock(&boost_mutex);
1426 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
1427 * induces a CPU stall for the time specified by stall_cpu.
1429 static int rcu_torture_stall(void *args)
1431 unsigned long stop_at;
1433 VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
1434 if (stall_cpu_holdoff > 0) {
1435 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
1436 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
1437 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
1439 if (!kthread_should_stop()) {
1440 stop_at = get_seconds() + stall_cpu;
1441 /* RCU CPU stall is expected behavior in following code. */
1442 pr_alert("rcu_torture_stall start.\n");
1445 while (ULONG_CMP_LT(get_seconds(), stop_at))
1446 continue; /* Induce RCU CPU stall warning. */
1449 pr_alert("rcu_torture_stall end.\n");
1451 torture_shutdown_absorb("rcu_torture_stall");
1452 while (!kthread_should_stop())
1453 schedule_timeout_interruptible(10 * HZ);
1457 /* Spawn CPU-stall kthread, if stall_cpu specified. */
1458 static int __init rcu_torture_stall_init(void)
1462 return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
1465 /* Callback function for RCU barrier testing. */
1466 static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
1468 atomic_inc(&barrier_cbs_invoked);
1471 /* kthread function to register callbacks used to test RCU barriers. */
1472 static int rcu_torture_barrier_cbs(void *arg)
1474 long myid = (long)arg;
1477 struct rcu_head rcu;
1479 init_rcu_head_on_stack(&rcu);
1480 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
1481 set_user_nice(current, MAX_NICE);
1483 wait_event(barrier_cbs_wq[myid],
1485 smp_load_acquire(&barrier_phase)) != lastphase ||
1486 torture_must_stop());
1487 lastphase = newphase;
1488 if (torture_must_stop())
1491 * The above smp_load_acquire() ensures barrier_phase load
1492 * is ordered before the folloiwng ->call().
1494 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
1495 if (atomic_dec_and_test(&barrier_cbs_count))
1496 wake_up(&barrier_wq);
1497 } while (!torture_must_stop());
1498 if (cur_ops->cb_barrier != NULL)
1499 cur_ops->cb_barrier();
1500 destroy_rcu_head_on_stack(&rcu);
1501 torture_kthread_stopping("rcu_torture_barrier_cbs");
1505 /* kthread function to drive and coordinate RCU barrier testing. */
1506 static int rcu_torture_barrier(void *arg)
1510 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
1512 atomic_set(&barrier_cbs_invoked, 0);
1513 atomic_set(&barrier_cbs_count, n_barrier_cbs);
1514 /* Ensure barrier_phase ordered after prior assignments. */
1515 smp_store_release(&barrier_phase, !barrier_phase);
1516 for (i = 0; i < n_barrier_cbs; i++)
1517 wake_up(&barrier_cbs_wq[i]);
1518 wait_event(barrier_wq,
1519 atomic_read(&barrier_cbs_count) == 0 ||
1520 torture_must_stop());
1521 if (torture_must_stop())
1523 n_barrier_attempts++;
1524 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
1525 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
1526 n_rcu_torture_barrier_error++;
1527 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
1528 atomic_read(&barrier_cbs_invoked),
1532 n_barrier_successes++;
1533 schedule_timeout_interruptible(HZ / 10);
1534 } while (!torture_must_stop());
1535 torture_kthread_stopping("rcu_torture_barrier");
1539 /* Initialize RCU barrier testing. */
1540 static int rcu_torture_barrier_init(void)
1545 if (n_barrier_cbs <= 0)
1547 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
1548 pr_alert("%s" TORTURE_FLAG
1549 " Call or barrier ops missing for %s,\n",
1550 torture_type, cur_ops->name);
1551 pr_alert("%s" TORTURE_FLAG
1552 " RCU barrier testing omitted from run.\n",
1556 atomic_set(&barrier_cbs_count, 0);
1557 atomic_set(&barrier_cbs_invoked, 0);
1559 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_tasks[0]),
1562 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_wq[0]),
1564 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
1566 for (i = 0; i < n_barrier_cbs; i++) {
1567 init_waitqueue_head(&barrier_cbs_wq[i]);
1568 ret = torture_create_kthread(rcu_torture_barrier_cbs,
1570 barrier_cbs_tasks[i]);
1574 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
1577 /* Clean up after RCU barrier testing. */
1578 static void rcu_torture_barrier_cleanup(void)
1582 torture_stop_kthread(rcu_torture_barrier, barrier_task);
1583 if (barrier_cbs_tasks != NULL) {
1584 for (i = 0; i < n_barrier_cbs; i++)
1585 torture_stop_kthread(rcu_torture_barrier_cbs,
1586 barrier_cbs_tasks[i]);
1587 kfree(barrier_cbs_tasks);
1588 barrier_cbs_tasks = NULL;
1590 if (barrier_cbs_wq != NULL) {
1591 kfree(barrier_cbs_wq);
1592 barrier_cbs_wq = NULL;
1596 static int rcutorture_cpu_notify(struct notifier_block *self,
1597 unsigned long action, void *hcpu)
1599 long cpu = (long)hcpu;
1603 case CPU_DOWN_FAILED:
1604 (void)rcutorture_booster_init(cpu);
1606 case CPU_DOWN_PREPARE:
1607 rcutorture_booster_cleanup(cpu);
1615 static struct notifier_block rcutorture_cpu_nb = {
1616 .notifier_call = rcutorture_cpu_notify,
1620 rcu_torture_cleanup(void)
1624 rcutorture_record_test_transition();
1625 if (torture_cleanup_begin()) {
1626 if (cur_ops->cb_barrier != NULL)
1627 cur_ops->cb_barrier();
1631 rcu_torture_barrier_cleanup();
1632 torture_stop_kthread(rcu_torture_stall, stall_task);
1633 torture_stop_kthread(rcu_torture_writer, writer_task);
1636 for (i = 0; i < nrealreaders; i++)
1637 torture_stop_kthread(rcu_torture_reader,
1639 kfree(reader_tasks);
1641 rcu_torture_current = NULL;
1643 if (fakewriter_tasks) {
1644 for (i = 0; i < nfakewriters; i++) {
1645 torture_stop_kthread(rcu_torture_fakewriter,
1646 fakewriter_tasks[i]);
1648 kfree(fakewriter_tasks);
1649 fakewriter_tasks = NULL;
1652 torture_stop_kthread(rcu_torture_stats, stats_task);
1653 torture_stop_kthread(rcu_torture_fqs, fqs_task);
1654 for (i = 0; i < ncbflooders; i++)
1655 torture_stop_kthread(rcu_torture_cbflood, cbflood_task[i]);
1656 if ((test_boost == 1 && cur_ops->can_boost) ||
1658 unregister_cpu_notifier(&rcutorture_cpu_nb);
1659 for_each_possible_cpu(i)
1660 rcutorture_booster_cleanup(i);
1664 * Wait for all RCU callbacks to fire, then do flavor-specific
1665 * cleanup operations.
1667 if (cur_ops->cb_barrier != NULL)
1668 cur_ops->cb_barrier();
1669 if (cur_ops->cleanup != NULL)
1672 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
1674 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
1675 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
1676 else if (torture_onoff_failures())
1677 rcu_torture_print_module_parms(cur_ops,
1678 "End of test: RCU_HOTPLUG");
1680 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
1681 torture_cleanup_end();
1684 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1685 static void rcu_torture_leak_cb(struct rcu_head *rhp)
1689 static void rcu_torture_err_cb(struct rcu_head *rhp)
1692 * This -might- happen due to race conditions, but is unlikely.
1693 * The scenario that leads to this happening is that the
1694 * first of the pair of duplicate callbacks is queued,
1695 * someone else starts a grace period that includes that
1696 * callback, then the second of the pair must wait for the
1697 * next grace period. Unlikely, but can happen. If it
1698 * does happen, the debug-objects subsystem won't have splatted.
1700 pr_alert("rcutorture: duplicated callback was invoked.\n");
1702 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1705 * Verify that double-free causes debug-objects to complain, but only
1706 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
1707 * cannot be carried out.
1709 static void rcu_test_debug_objects(void)
1711 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1712 struct rcu_head rh1;
1713 struct rcu_head rh2;
1715 init_rcu_head_on_stack(&rh1);
1716 init_rcu_head_on_stack(&rh2);
1717 pr_alert("rcutorture: WARN: Duplicate call_rcu() test starting.\n");
1719 /* Try to queue the rh2 pair of callbacks for the same grace period. */
1720 preempt_disable(); /* Prevent preemption from interrupting test. */
1721 rcu_read_lock(); /* Make it impossible to finish a grace period. */
1722 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
1723 local_irq_disable(); /* Make it harder to start a new grace period. */
1724 call_rcu(&rh2, rcu_torture_leak_cb);
1725 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
1730 /* Wait for them all to get done so we can safely return. */
1732 pr_alert("rcutorture: WARN: Duplicate call_rcu() test complete.\n");
1733 destroy_rcu_head_on_stack(&rh1);
1734 destroy_rcu_head_on_stack(&rh2);
1735 #else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1736 pr_alert("rcutorture: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n");
1737 #endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1741 rcu_torture_init(void)
1746 static struct rcu_torture_ops *torture_ops[] = {
1747 &rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops,
1748 &sched_ops, RCUTORTURE_TASKS_OPS
1751 if (!torture_init_begin(torture_type, verbose, &torture_runnable))
1754 /* Process args and tell the world that the torturer is on the job. */
1755 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1756 cur_ops = torture_ops[i];
1757 if (strcmp(torture_type, cur_ops->name) == 0)
1760 if (i == ARRAY_SIZE(torture_ops)) {
1761 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
1763 pr_alert("rcu-torture types:");
1764 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1765 pr_alert(" %s", torture_ops[i]->name);
1770 if (cur_ops->fqs == NULL && fqs_duration != 0) {
1771 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
1777 if (nreaders >= 0) {
1778 nrealreaders = nreaders;
1780 nrealreaders = num_online_cpus() - 2 - nreaders;
1781 if (nrealreaders <= 0)
1784 rcu_torture_print_module_parms(cur_ops, "Start of test");
1786 /* Set up the freelist. */
1788 INIT_LIST_HEAD(&rcu_torture_freelist);
1789 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1790 rcu_tortures[i].rtort_mbtest = 0;
1791 list_add_tail(&rcu_tortures[i].rtort_free,
1792 &rcu_torture_freelist);
1795 /* Initialize the statistics so that each run gets its own numbers. */
1797 rcu_torture_current = NULL;
1798 rcu_torture_current_version = 0;
1799 atomic_set(&n_rcu_torture_alloc, 0);
1800 atomic_set(&n_rcu_torture_alloc_fail, 0);
1801 atomic_set(&n_rcu_torture_free, 0);
1802 atomic_set(&n_rcu_torture_mberror, 0);
1803 atomic_set(&n_rcu_torture_error, 0);
1804 n_rcu_torture_barrier_error = 0;
1805 n_rcu_torture_boost_ktrerror = 0;
1806 n_rcu_torture_boost_rterror = 0;
1807 n_rcu_torture_boost_failure = 0;
1808 n_rcu_torture_boosts = 0;
1809 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1810 atomic_set(&rcu_torture_wcount[i], 0);
1811 for_each_possible_cpu(cpu) {
1812 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1813 per_cpu(rcu_torture_count, cpu)[i] = 0;
1814 per_cpu(rcu_torture_batch, cpu)[i] = 0;
1818 /* Start up the kthreads. */
1820 firsterr = torture_create_kthread(rcu_torture_writer, NULL,
1824 if (nfakewriters > 0) {
1825 fakewriter_tasks = kzalloc(nfakewriters *
1826 sizeof(fakewriter_tasks[0]),
1828 if (fakewriter_tasks == NULL) {
1829 VERBOSE_TOROUT_ERRSTRING("out of memory");
1834 for (i = 0; i < nfakewriters; i++) {
1835 firsterr = torture_create_kthread(rcu_torture_fakewriter,
1836 NULL, fakewriter_tasks[i]);
1840 reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
1842 if (reader_tasks == NULL) {
1843 VERBOSE_TOROUT_ERRSTRING("out of memory");
1847 for (i = 0; i < nrealreaders; i++) {
1848 firsterr = torture_create_kthread(rcu_torture_reader, NULL,
1853 if (stat_interval > 0) {
1854 firsterr = torture_create_kthread(rcu_torture_stats, NULL,
1859 if (test_no_idle_hz && shuffle_interval > 0) {
1860 firsterr = torture_shuffle_init(shuffle_interval * HZ);
1867 firsterr = torture_stutter_init(stutter * HZ);
1871 if (fqs_duration < 0)
1874 /* Create the fqs thread */
1875 firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
1880 if (test_boost_interval < 1)
1881 test_boost_interval = 1;
1882 if (test_boost_duration < 2)
1883 test_boost_duration = 2;
1884 if ((test_boost == 1 && cur_ops->can_boost) ||
1887 boost_starttime = jiffies + test_boost_interval * HZ;
1888 register_cpu_notifier(&rcutorture_cpu_nb);
1889 for_each_possible_cpu(i) {
1890 if (cpu_is_offline(i))
1891 continue; /* Heuristic: CPU can go offline. */
1892 firsterr = rcutorture_booster_init(i);
1897 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
1900 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval * HZ);
1903 firsterr = rcu_torture_stall_init();
1906 firsterr = rcu_torture_barrier_init();
1910 rcu_test_debug_objects();
1911 if (cbflood_n_burst > 0) {
1912 /* Create the cbflood threads */
1913 ncbflooders = (num_online_cpus() + 3) / 4;
1914 cbflood_task = kcalloc(ncbflooders, sizeof(*cbflood_task),
1916 if (!cbflood_task) {
1917 VERBOSE_TOROUT_ERRSTRING("out of memory");
1921 for (i = 0; i < ncbflooders; i++) {
1922 firsterr = torture_create_kthread(rcu_torture_cbflood,
1929 rcutorture_record_test_transition();
1935 rcu_torture_cleanup();
1939 module_init(rcu_torture_init);
1940 module_exit(rcu_torture_cleanup);