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/signal.h>
36 #include <uapi/linux/sched/types.h>
37 #include <linux/atomic.h>
38 #include <linux/bitops.h>
39 #include <linux/completion.h>
40 #include <linux/moduleparam.h>
41 #include <linux/percpu.h>
42 #include <linux/notifier.h>
43 #include <linux/reboot.h>
44 #include <linux/freezer.h>
45 #include <linux/cpu.h>
46 #include <linux/delay.h>
47 #include <linux/stat.h>
48 #include <linux/srcu.h>
49 #include <linux/slab.h>
50 #include <linux/trace_clock.h>
51 #include <asm/byteorder.h>
52 #include <linux/torture.h>
53 #include <linux/vmalloc.h>
57 MODULE_LICENSE("GPL");
58 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
61 torture_param(int, cbflood_inter_holdoff, HZ,
62 "Holdoff between floods (jiffies)");
63 torture_param(int, cbflood_intra_holdoff, 1,
64 "Holdoff between bursts (jiffies)");
65 torture_param(int, cbflood_n_burst, 3, "# bursts in flood, zero to disable");
66 torture_param(int, cbflood_n_per_burst, 20000,
67 "# callbacks per burst in flood");
68 torture_param(int, fqs_duration, 0,
69 "Duration of fqs bursts (us), 0 to disable");
70 torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
71 torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
72 torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
73 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
74 torture_param(bool, gp_normal, false,
75 "Use normal (non-expedited) GP wait primitives");
76 torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
77 torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
78 torture_param(int, n_barrier_cbs, 0,
79 "# of callbacks/kthreads for barrier testing");
80 torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
81 torture_param(int, nreaders, -1, "Number of RCU reader threads");
82 torture_param(int, object_debug, 0,
83 "Enable debug-object double call_rcu() testing");
84 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
85 torture_param(int, onoff_interval, 0,
86 "Time between CPU hotplugs (s), 0=disable");
87 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
88 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
89 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
90 torture_param(int, stall_cpu_holdoff, 10,
91 "Time to wait before starting stall (s).");
92 torture_param(int, stat_interval, 60,
93 "Number of seconds between stats printk()s");
94 torture_param(int, stutter, 5, "Number of seconds to run/halt test");
95 torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
96 torture_param(int, test_boost_duration, 4,
97 "Duration of each boost test, seconds.");
98 torture_param(int, test_boost_interval, 7,
99 "Interval between boost tests, seconds.");
100 torture_param(bool, test_no_idle_hz, true,
101 "Test support for tickless idle CPUs");
102 torture_param(bool, verbose, true,
103 "Enable verbose debugging printk()s");
105 static char *torture_type = "rcu";
106 module_param(torture_type, charp, 0444);
107 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, ...)");
109 static int nrealreaders;
110 static int ncbflooders;
111 static struct task_struct *writer_task;
112 static struct task_struct **fakewriter_tasks;
113 static struct task_struct **reader_tasks;
114 static struct task_struct *stats_task;
115 static struct task_struct **cbflood_task;
116 static struct task_struct *fqs_task;
117 static struct task_struct *boost_tasks[NR_CPUS];
118 static struct task_struct *stall_task;
119 static struct task_struct **barrier_cbs_tasks;
120 static struct task_struct *barrier_task;
122 #define RCU_TORTURE_PIPE_LEN 10
125 struct rcu_head rtort_rcu;
126 int rtort_pipe_count;
127 struct list_head rtort_free;
131 static LIST_HEAD(rcu_torture_freelist);
132 static struct rcu_torture __rcu *rcu_torture_current;
133 static unsigned long rcu_torture_current_version;
134 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
135 static DEFINE_SPINLOCK(rcu_torture_lock);
136 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count);
137 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch);
138 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
139 static atomic_t n_rcu_torture_alloc;
140 static atomic_t n_rcu_torture_alloc_fail;
141 static atomic_t n_rcu_torture_free;
142 static atomic_t n_rcu_torture_mberror;
143 static atomic_t n_rcu_torture_error;
144 static long n_rcu_torture_barrier_error;
145 static long n_rcu_torture_boost_ktrerror;
146 static long n_rcu_torture_boost_rterror;
147 static long n_rcu_torture_boost_failure;
148 static long n_rcu_torture_boosts;
149 static long n_rcu_torture_timers;
150 static long n_barrier_attempts;
151 static long n_barrier_successes;
152 static atomic_long_t n_cbfloods;
153 static struct list_head rcu_torture_removed;
155 static int rcu_torture_writer_state;
156 #define RTWS_FIXED_DELAY 0
158 #define RTWS_REPLACE 2
159 #define RTWS_DEF_FREE 3
160 #define RTWS_EXP_SYNC 4
161 #define RTWS_COND_GET 5
162 #define RTWS_COND_SYNC 6
164 #define RTWS_STUTTER 8
165 #define RTWS_STOPPING 9
166 static const char * const rcu_torture_writer_state_names[] = {
179 static const char *rcu_torture_writer_state_getname(void)
181 unsigned int i = READ_ONCE(rcu_torture_writer_state);
183 if (i >= ARRAY_SIZE(rcu_torture_writer_state_names))
185 return rcu_torture_writer_state_names[i];
188 static int torture_runnable = IS_ENABLED(MODULE);
189 module_param(torture_runnable, int, 0444);
190 MODULE_PARM_DESC(torture_runnable, "Start rcutorture at boot");
192 #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
193 #define rcu_can_boost() 1
194 #else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
195 #define rcu_can_boost() 0
196 #endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
198 #ifdef CONFIG_RCU_TRACE
199 static u64 notrace rcu_trace_clock_local(void)
201 u64 ts = trace_clock_local();
202 unsigned long __maybe_unused ts_rem = do_div(ts, NSEC_PER_USEC);
205 #else /* #ifdef CONFIG_RCU_TRACE */
206 static u64 notrace rcu_trace_clock_local(void)
210 #endif /* #else #ifdef CONFIG_RCU_TRACE */
212 static unsigned long boost_starttime; /* jiffies of next boost test start. */
213 static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
214 /* and boost task create/destroy. */
215 static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
216 static bool barrier_phase; /* Test phase. */
217 static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
218 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
219 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
222 * Allocate an element from the rcu_tortures pool.
224 static struct rcu_torture *
225 rcu_torture_alloc(void)
229 spin_lock_bh(&rcu_torture_lock);
230 if (list_empty(&rcu_torture_freelist)) {
231 atomic_inc(&n_rcu_torture_alloc_fail);
232 spin_unlock_bh(&rcu_torture_lock);
235 atomic_inc(&n_rcu_torture_alloc);
236 p = rcu_torture_freelist.next;
238 spin_unlock_bh(&rcu_torture_lock);
239 return container_of(p, struct rcu_torture, rtort_free);
243 * Free an element to the rcu_tortures pool.
246 rcu_torture_free(struct rcu_torture *p)
248 atomic_inc(&n_rcu_torture_free);
249 spin_lock_bh(&rcu_torture_lock);
250 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
251 spin_unlock_bh(&rcu_torture_lock);
255 * Operations vector for selecting different types of tests.
258 struct rcu_torture_ops {
261 void (*cleanup)(void);
262 int (*readlock)(void);
263 void (*read_delay)(struct torture_random_state *rrsp);
264 void (*readunlock)(int idx);
265 unsigned long (*started)(void);
266 unsigned long (*completed)(void);
267 void (*deferred_free)(struct rcu_torture *p);
269 void (*exp_sync)(void);
270 unsigned long (*get_state)(void);
271 void (*cond_sync)(unsigned long oldstate);
272 call_rcu_func_t call;
273 void (*cb_barrier)(void);
281 static struct rcu_torture_ops *cur_ops;
284 * Definitions for rcu torture testing.
287 static int rcu_torture_read_lock(void) __acquires(RCU)
293 static void rcu_read_delay(struct torture_random_state *rrsp)
295 unsigned long started;
296 unsigned long completed;
297 const unsigned long shortdelay_us = 200;
298 const unsigned long longdelay_ms = 50;
299 unsigned long long ts;
301 /* We want a short delay sometimes to make a reader delay the grace
302 * period, and we want a long delay occasionally to trigger
303 * force_quiescent_state. */
305 if (!(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) {
306 started = cur_ops->completed();
307 ts = rcu_trace_clock_local();
308 mdelay(longdelay_ms);
309 completed = cur_ops->completed();
310 do_trace_rcu_torture_read(cur_ops->name, NULL, ts,
313 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
314 udelay(shortdelay_us);
315 #ifdef CONFIG_PREEMPT
316 if (!preempt_count() &&
317 !(torture_random(rrsp) % (nrealreaders * 20000)))
318 preempt_schedule(); /* No QS if preempt_disable() in effect */
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 .started = rcu_batches_started,
404 .completed = rcu_batches_completed,
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 .started = rcu_batches_started_bh,
446 .completed = rcu_batches_completed_bh,
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 .started = rcu_no_completed,
490 .completed = rcu_no_completed,
491 .deferred_free = rcu_busted_torture_deferred_free,
492 .sync = synchronize_rcu_busted,
493 .exp_sync = synchronize_rcu_busted,
494 .call = call_rcu_busted,
503 * Definitions for srcu torture testing.
506 DEFINE_STATIC_SRCU(srcu_ctl);
507 static struct srcu_struct srcu_ctld;
508 static struct srcu_struct *srcu_ctlp = &srcu_ctl;
510 static int srcu_torture_read_lock(void) __acquires(srcu_ctlp)
512 return srcu_read_lock(srcu_ctlp);
515 static void srcu_read_delay(struct torture_random_state *rrsp)
518 const long uspertick = 1000000 / HZ;
519 const long longdelay = 10;
521 /* We want there to be long-running readers, but not all the time. */
523 delay = torture_random(rrsp) %
524 (nrealreaders * 2 * longdelay * uspertick);
526 schedule_timeout_interruptible(longdelay);
528 rcu_read_delay(rrsp);
531 static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp)
533 srcu_read_unlock(srcu_ctlp, idx);
536 static unsigned long srcu_torture_completed(void)
538 return srcu_batches_completed(srcu_ctlp);
541 static void srcu_torture_deferred_free(struct rcu_torture *rp)
543 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
546 static void srcu_torture_synchronize(void)
548 synchronize_srcu(srcu_ctlp);
551 static void srcu_torture_call(struct rcu_head *head,
554 call_srcu(srcu_ctlp, head, func);
557 static void srcu_torture_barrier(void)
559 srcu_barrier(srcu_ctlp);
562 static void srcu_torture_stats(void)
564 int __maybe_unused cpu;
567 #ifdef CONFIG_TREE_SRCU
568 idx = srcu_ctlp->srcu_idx & 0x1;
569 pr_alert("%s%s Tree SRCU per-CPU(idx=%d):",
570 torture_type, TORTURE_FLAG, idx);
571 for_each_possible_cpu(cpu) {
572 unsigned long l0, l1;
573 unsigned long u0, u1;
575 struct srcu_data *counts;
577 counts = per_cpu_ptr(srcu_ctlp->sda, cpu);
578 u0 = counts->srcu_unlock_count[!idx];
579 u1 = counts->srcu_unlock_count[idx];
582 * Make sure that a lock is always counted if the corresponding
587 l0 = counts->srcu_lock_count[!idx];
588 l1 = counts->srcu_lock_count[idx];
592 pr_cont(" %d(%ld,%ld)", cpu, c0, c1);
595 #elif defined(CONFIG_TINY_SRCU)
596 idx = READ_ONCE(srcu_ctlp->srcu_idx) & 0x1;
597 pr_alert("%s%s Tiny SRCU per-CPU(idx=%d): (%hd,%hd)\n",
598 torture_type, TORTURE_FLAG, idx,
599 READ_ONCE(srcu_ctlp->srcu_lock_nesting[!idx]),
600 READ_ONCE(srcu_ctlp->srcu_lock_nesting[idx]));
604 static void srcu_torture_synchronize_expedited(void)
606 synchronize_srcu_expedited(srcu_ctlp);
609 static struct rcu_torture_ops srcu_ops = {
610 .ttype = SRCU_FLAVOR,
611 .init = rcu_sync_torture_init,
612 .readlock = srcu_torture_read_lock,
613 .read_delay = srcu_read_delay,
614 .readunlock = srcu_torture_read_unlock,
616 .completed = srcu_torture_completed,
617 .deferred_free = srcu_torture_deferred_free,
618 .sync = srcu_torture_synchronize,
619 .exp_sync = srcu_torture_synchronize_expedited,
620 .call = srcu_torture_call,
621 .cb_barrier = srcu_torture_barrier,
622 .stats = srcu_torture_stats,
626 static void srcu_torture_init(void)
628 rcu_sync_torture_init();
629 WARN_ON(init_srcu_struct(&srcu_ctld));
630 srcu_ctlp = &srcu_ctld;
633 static void srcu_torture_cleanup(void)
635 cleanup_srcu_struct(&srcu_ctld);
636 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
639 /* As above, but dynamically allocated. */
640 static struct rcu_torture_ops srcud_ops = {
641 .ttype = SRCU_FLAVOR,
642 .init = srcu_torture_init,
643 .cleanup = srcu_torture_cleanup,
644 .readlock = srcu_torture_read_lock,
645 .read_delay = srcu_read_delay,
646 .readunlock = srcu_torture_read_unlock,
648 .completed = srcu_torture_completed,
649 .deferred_free = srcu_torture_deferred_free,
650 .sync = srcu_torture_synchronize,
651 .exp_sync = srcu_torture_synchronize_expedited,
652 .call = srcu_torture_call,
653 .cb_barrier = srcu_torture_barrier,
654 .stats = srcu_torture_stats,
659 * Definitions for sched torture testing.
662 static int sched_torture_read_lock(void)
668 static void sched_torture_read_unlock(int idx)
673 static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
675 call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
678 static struct rcu_torture_ops sched_ops = {
679 .ttype = RCU_SCHED_FLAVOR,
680 .init = rcu_sync_torture_init,
681 .readlock = sched_torture_read_lock,
682 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
683 .readunlock = sched_torture_read_unlock,
684 .started = rcu_batches_started_sched,
685 .completed = rcu_batches_completed_sched,
686 .deferred_free = rcu_sched_torture_deferred_free,
687 .sync = synchronize_sched,
688 .exp_sync = synchronize_sched_expedited,
689 .get_state = get_state_synchronize_sched,
690 .cond_sync = cond_synchronize_sched,
691 .call = call_rcu_sched,
692 .cb_barrier = rcu_barrier_sched,
693 .fqs = rcu_sched_force_quiescent_state,
699 #ifdef CONFIG_TASKS_RCU
702 * Definitions for RCU-tasks torture testing.
705 static int tasks_torture_read_lock(void)
710 static void tasks_torture_read_unlock(int idx)
714 static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
716 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
719 static struct rcu_torture_ops tasks_ops = {
720 .ttype = RCU_TASKS_FLAVOR,
721 .init = rcu_sync_torture_init,
722 .readlock = tasks_torture_read_lock,
723 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
724 .readunlock = tasks_torture_read_unlock,
725 .started = rcu_no_completed,
726 .completed = rcu_no_completed,
727 .deferred_free = rcu_tasks_torture_deferred_free,
728 .sync = synchronize_rcu_tasks,
729 .exp_sync = synchronize_rcu_tasks,
730 .call = call_rcu_tasks,
731 .cb_barrier = rcu_barrier_tasks,
738 #define RCUTORTURE_TASKS_OPS &tasks_ops,
740 static bool __maybe_unused torturing_tasks(void)
742 return cur_ops == &tasks_ops;
745 #else /* #ifdef CONFIG_TASKS_RCU */
747 #define RCUTORTURE_TASKS_OPS
749 static bool __maybe_unused torturing_tasks(void)
754 #endif /* #else #ifdef CONFIG_TASKS_RCU */
757 * RCU torture priority-boost testing. Runs one real-time thread per
758 * CPU for moderate bursts, repeatedly registering RCU callbacks and
759 * spinning waiting for them to be invoked. If a given callback takes
760 * too long to be invoked, we assume that priority inversion has occurred.
763 struct rcu_boost_inflight {
768 static void rcu_torture_boost_cb(struct rcu_head *head)
770 struct rcu_boost_inflight *rbip =
771 container_of(head, struct rcu_boost_inflight, rcu);
773 /* Ensure RCU-core accesses precede clearing ->inflight */
774 smp_store_release(&rbip->inflight, 0);
777 static int rcu_torture_boost(void *arg)
779 unsigned long call_rcu_time;
780 unsigned long endtime;
781 unsigned long oldstarttime;
782 struct rcu_boost_inflight rbi = { .inflight = 0 };
783 struct sched_param sp;
785 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
787 /* Set real-time priority. */
788 sp.sched_priority = 1;
789 if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
790 VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!");
791 n_rcu_torture_boost_rterror++;
794 init_rcu_head_on_stack(&rbi.rcu);
795 /* Each pass through the following loop does one boost-test cycle. */
797 /* Wait for the next test interval. */
798 oldstarttime = boost_starttime;
799 while (ULONG_CMP_LT(jiffies, oldstarttime)) {
800 schedule_timeout_interruptible(oldstarttime - jiffies);
801 stutter_wait("rcu_torture_boost");
802 if (torture_must_stop())
806 /* Do one boost-test interval. */
807 endtime = oldstarttime + test_boost_duration * HZ;
808 call_rcu_time = jiffies;
809 while (ULONG_CMP_LT(jiffies, endtime)) {
810 /* If we don't have a callback in flight, post one. */
811 if (!smp_load_acquire(&rbi.inflight)) {
812 /* RCU core before ->inflight = 1. */
813 smp_store_release(&rbi.inflight, 1);
814 call_rcu(&rbi.rcu, rcu_torture_boost_cb);
815 if (jiffies - call_rcu_time >
816 test_boost_duration * HZ - HZ / 2) {
817 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
818 n_rcu_torture_boost_failure++;
820 call_rcu_time = jiffies;
822 stutter_wait("rcu_torture_boost");
823 if (torture_must_stop())
828 * Set the start time of the next test interval.
829 * Yes, this is vulnerable to long delays, but such
830 * delays simply cause a false negative for the next
831 * interval. Besides, we are running at RT priority,
832 * so delays should be relatively rare.
834 while (oldstarttime == boost_starttime &&
835 !kthread_should_stop()) {
836 if (mutex_trylock(&boost_mutex)) {
837 boost_starttime = jiffies +
838 test_boost_interval * HZ;
839 n_rcu_torture_boosts++;
840 mutex_unlock(&boost_mutex);
843 schedule_timeout_uninterruptible(1);
846 /* Go do the stutter. */
847 checkwait: stutter_wait("rcu_torture_boost");
848 } while (!torture_must_stop());
850 /* Clean up and exit. */
851 while (!kthread_should_stop() || smp_load_acquire(&rbi.inflight)) {
852 torture_shutdown_absorb("rcu_torture_boost");
853 schedule_timeout_uninterruptible(1);
855 destroy_rcu_head_on_stack(&rbi.rcu);
856 torture_kthread_stopping("rcu_torture_boost");
860 static void rcu_torture_cbflood_cb(struct rcu_head *rhp)
865 * RCU torture callback-flood kthread. Repeatedly induces bursts of calls
866 * to call_rcu() or analogous, increasing the probability of occurrence
867 * of callback-overflow corner cases.
870 rcu_torture_cbflood(void *arg)
875 struct rcu_head *rhp;
877 if (cbflood_n_per_burst > 0 &&
878 cbflood_inter_holdoff > 0 &&
879 cbflood_intra_holdoff > 0 &&
881 cur_ops->cb_barrier) {
882 rhp = vmalloc(sizeof(*rhp) *
883 cbflood_n_burst * cbflood_n_per_burst);
887 VERBOSE_TOROUT_STRING("rcu_torture_cbflood disabled: Bad args or OOM");
890 VERBOSE_TOROUT_STRING("rcu_torture_cbflood task started");
892 schedule_timeout_interruptible(cbflood_inter_holdoff);
893 atomic_long_inc(&n_cbfloods);
894 WARN_ON(signal_pending(current));
895 for (i = 0; i < cbflood_n_burst; i++) {
896 for (j = 0; j < cbflood_n_per_burst; j++) {
897 cur_ops->call(&rhp[i * cbflood_n_per_burst + j],
898 rcu_torture_cbflood_cb);
900 schedule_timeout_interruptible(cbflood_intra_holdoff);
901 WARN_ON(signal_pending(current));
903 cur_ops->cb_barrier();
904 stutter_wait("rcu_torture_cbflood");
905 } while (!torture_must_stop());
908 torture_kthread_stopping("rcu_torture_cbflood");
913 * RCU torture force-quiescent-state kthread. Repeatedly induces
914 * bursts of calls to force_quiescent_state(), increasing the probability
915 * of occurrence of some important types of race conditions.
918 rcu_torture_fqs(void *arg)
920 unsigned long fqs_resume_time;
921 int fqs_burst_remaining;
923 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
925 fqs_resume_time = jiffies + fqs_stutter * HZ;
926 while (ULONG_CMP_LT(jiffies, fqs_resume_time) &&
927 !kthread_should_stop()) {
928 schedule_timeout_interruptible(1);
930 fqs_burst_remaining = fqs_duration;
931 while (fqs_burst_remaining > 0 &&
932 !kthread_should_stop()) {
935 fqs_burst_remaining -= fqs_holdoff;
937 stutter_wait("rcu_torture_fqs");
938 } while (!torture_must_stop());
939 torture_kthread_stopping("rcu_torture_fqs");
944 * RCU torture writer kthread. Repeatedly substitutes a new structure
945 * for that pointed to by rcu_torture_current, freeing the old structure
946 * after a series of grace periods (the "pipeline").
949 rcu_torture_writer(void *arg)
951 bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
953 unsigned long gp_snap;
954 bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal;
955 bool gp_sync1 = gp_sync;
957 struct rcu_torture *rp;
958 struct rcu_torture *old_rp;
959 static DEFINE_TORTURE_RANDOM(rand);
960 int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC,
961 RTWS_COND_GET, RTWS_SYNC };
964 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
966 pr_alert("%s" TORTURE_FLAG
967 " GP expediting controlled from boot/sysfs for %s,\n",
968 torture_type, cur_ops->name);
969 pr_alert("%s" TORTURE_FLAG
970 " Disabled dynamic grace-period expediting.\n",
974 /* Initialize synctype[] array. If none set, take default. */
975 if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync1)
976 gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true;
977 if (gp_cond1 && cur_ops->get_state && cur_ops->cond_sync)
978 synctype[nsynctypes++] = RTWS_COND_GET;
979 else if (gp_cond && (!cur_ops->get_state || !cur_ops->cond_sync))
980 pr_alert("rcu_torture_writer: gp_cond without primitives.\n");
981 if (gp_exp1 && cur_ops->exp_sync)
982 synctype[nsynctypes++] = RTWS_EXP_SYNC;
983 else if (gp_exp && !cur_ops->exp_sync)
984 pr_alert("rcu_torture_writer: gp_exp without primitives.\n");
985 if (gp_normal1 && cur_ops->deferred_free)
986 synctype[nsynctypes++] = RTWS_DEF_FREE;
987 else if (gp_normal && !cur_ops->deferred_free)
988 pr_alert("rcu_torture_writer: gp_normal without primitives.\n");
989 if (gp_sync1 && cur_ops->sync)
990 synctype[nsynctypes++] = RTWS_SYNC;
991 else if (gp_sync && !cur_ops->sync)
992 pr_alert("rcu_torture_writer: gp_sync without primitives.\n");
993 if (WARN_ONCE(nsynctypes == 0,
994 "rcu_torture_writer: No update-side primitives.\n")) {
996 * No updates primitives, so don't try updating.
997 * The resulting test won't be testing much, hence the
1000 rcu_torture_writer_state = RTWS_STOPPING;
1001 torture_kthread_stopping("rcu_torture_writer");
1005 rcu_torture_writer_state = RTWS_FIXED_DELAY;
1006 schedule_timeout_uninterruptible(1);
1007 rp = rcu_torture_alloc();
1010 rp->rtort_pipe_count = 0;
1011 rcu_torture_writer_state = RTWS_DELAY;
1012 udelay(torture_random(&rand) & 0x3ff);
1013 rcu_torture_writer_state = RTWS_REPLACE;
1014 old_rp = rcu_dereference_check(rcu_torture_current,
1015 current == writer_task);
1016 rp->rtort_mbtest = 1;
1017 rcu_assign_pointer(rcu_torture_current, rp);
1018 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
1020 i = old_rp->rtort_pipe_count;
1021 if (i > RCU_TORTURE_PIPE_LEN)
1022 i = RCU_TORTURE_PIPE_LEN;
1023 atomic_inc(&rcu_torture_wcount[i]);
1024 old_rp->rtort_pipe_count++;
1025 switch (synctype[torture_random(&rand) % nsynctypes]) {
1027 rcu_torture_writer_state = RTWS_DEF_FREE;
1028 cur_ops->deferred_free(old_rp);
1031 rcu_torture_writer_state = RTWS_EXP_SYNC;
1032 cur_ops->exp_sync();
1033 rcu_torture_pipe_update(old_rp);
1036 rcu_torture_writer_state = RTWS_COND_GET;
1037 gp_snap = cur_ops->get_state();
1038 i = torture_random(&rand) % 16;
1040 schedule_timeout_interruptible(i);
1041 udelay(torture_random(&rand) % 1000);
1042 rcu_torture_writer_state = RTWS_COND_SYNC;
1043 cur_ops->cond_sync(gp_snap);
1044 rcu_torture_pipe_update(old_rp);
1047 rcu_torture_writer_state = RTWS_SYNC;
1049 rcu_torture_pipe_update(old_rp);
1056 rcutorture_record_progress(++rcu_torture_current_version);
1057 /* Cycle through nesting levels of rcu_expedite_gp() calls. */
1059 !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
1060 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
1061 if (expediting >= 0)
1064 rcu_unexpedite_gp();
1065 if (++expediting > 3)
1066 expediting = -expediting;
1068 rcu_torture_writer_state = RTWS_STUTTER;
1069 stutter_wait("rcu_torture_writer");
1070 } while (!torture_must_stop());
1071 /* Reset expediting back to unexpedited. */
1073 expediting = -expediting;
1074 while (can_expedite && expediting++ < 0)
1075 rcu_unexpedite_gp();
1076 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
1077 rcu_torture_writer_state = RTWS_STOPPING;
1078 torture_kthread_stopping("rcu_torture_writer");
1083 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
1084 * delay between calls.
1087 rcu_torture_fakewriter(void *arg)
1089 DEFINE_TORTURE_RANDOM(rand);
1091 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1092 set_user_nice(current, MAX_NICE);
1095 schedule_timeout_uninterruptible(1 + torture_random(&rand)%10);
1096 udelay(torture_random(&rand) & 0x3ff);
1097 if (cur_ops->cb_barrier != NULL &&
1098 torture_random(&rand) % (nfakewriters * 8) == 0) {
1099 cur_ops->cb_barrier();
1100 } else if (gp_normal == gp_exp) {
1101 if (torture_random(&rand) & 0x80)
1104 cur_ops->exp_sync();
1105 } else if (gp_normal) {
1108 cur_ops->exp_sync();
1110 stutter_wait("rcu_torture_fakewriter");
1111 } while (!torture_must_stop());
1113 torture_kthread_stopping("rcu_torture_fakewriter");
1118 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
1119 * incrementing the corresponding element of the pipeline array. The
1120 * counter in the element should never be greater than 1, otherwise, the
1121 * RCU implementation is broken.
1123 static void rcu_torture_timer(unsigned long unused)
1126 unsigned long started;
1127 unsigned long completed;
1128 static DEFINE_TORTURE_RANDOM(rand);
1129 static DEFINE_SPINLOCK(rand_lock);
1130 struct rcu_torture *p;
1132 unsigned long long ts;
1134 idx = cur_ops->readlock();
1135 if (cur_ops->started)
1136 started = cur_ops->started();
1138 started = cur_ops->completed();
1139 ts = rcu_trace_clock_local();
1140 p = rcu_dereference_check(rcu_torture_current,
1141 rcu_read_lock_bh_held() ||
1142 rcu_read_lock_sched_held() ||
1143 srcu_read_lock_held(srcu_ctlp) ||
1146 /* Leave because rcu_torture_writer is not yet underway */
1147 cur_ops->readunlock(idx);
1150 if (p->rtort_mbtest == 0)
1151 atomic_inc(&n_rcu_torture_mberror);
1152 spin_lock(&rand_lock);
1153 cur_ops->read_delay(&rand);
1154 n_rcu_torture_timers++;
1155 spin_unlock(&rand_lock);
1157 pipe_count = p->rtort_pipe_count;
1158 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1159 /* Should not happen, but... */
1160 pipe_count = RCU_TORTURE_PIPE_LEN;
1162 completed = cur_ops->completed();
1163 if (pipe_count > 1) {
1164 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, ts,
1165 started, completed);
1166 rcu_ftrace_dump(DUMP_ALL);
1168 __this_cpu_inc(rcu_torture_count[pipe_count]);
1169 completed = completed - started;
1170 if (cur_ops->started)
1172 if (completed > RCU_TORTURE_PIPE_LEN) {
1173 /* Should not happen, but... */
1174 completed = RCU_TORTURE_PIPE_LEN;
1176 __this_cpu_inc(rcu_torture_batch[completed]);
1178 cur_ops->readunlock(idx);
1182 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
1183 * incrementing the corresponding element of the pipeline array. The
1184 * counter in the element should never be greater than 1, otherwise, the
1185 * RCU implementation is broken.
1188 rcu_torture_reader(void *arg)
1190 unsigned long started;
1191 unsigned long completed;
1193 DEFINE_TORTURE_RANDOM(rand);
1194 struct rcu_torture *p;
1196 struct timer_list t;
1197 unsigned long long ts;
1199 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
1200 set_user_nice(current, MAX_NICE);
1201 if (irqreader && cur_ops->irq_capable)
1202 setup_timer_on_stack(&t, rcu_torture_timer, 0);
1205 if (irqreader && cur_ops->irq_capable) {
1206 if (!timer_pending(&t))
1207 mod_timer(&t, jiffies + 1);
1209 idx = cur_ops->readlock();
1210 if (cur_ops->started)
1211 started = cur_ops->started();
1213 started = cur_ops->completed();
1214 ts = rcu_trace_clock_local();
1215 p = rcu_dereference_check(rcu_torture_current,
1216 rcu_read_lock_bh_held() ||
1217 rcu_read_lock_sched_held() ||
1218 srcu_read_lock_held(srcu_ctlp) ||
1221 /* Wait for rcu_torture_writer to get underway */
1222 cur_ops->readunlock(idx);
1223 schedule_timeout_interruptible(HZ);
1226 if (p->rtort_mbtest == 0)
1227 atomic_inc(&n_rcu_torture_mberror);
1228 cur_ops->read_delay(&rand);
1230 pipe_count = p->rtort_pipe_count;
1231 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1232 /* Should not happen, but... */
1233 pipe_count = RCU_TORTURE_PIPE_LEN;
1235 completed = cur_ops->completed();
1236 if (pipe_count > 1) {
1237 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
1238 ts, started, completed);
1239 rcu_ftrace_dump(DUMP_ALL);
1241 __this_cpu_inc(rcu_torture_count[pipe_count]);
1242 completed = completed - started;
1243 if (cur_ops->started)
1245 if (completed > RCU_TORTURE_PIPE_LEN) {
1246 /* Should not happen, but... */
1247 completed = RCU_TORTURE_PIPE_LEN;
1249 __this_cpu_inc(rcu_torture_batch[completed]);
1251 cur_ops->readunlock(idx);
1252 stutter_wait("rcu_torture_reader");
1253 } while (!torture_must_stop());
1254 if (irqreader && cur_ops->irq_capable) {
1256 destroy_timer_on_stack(&t);
1258 torture_kthread_stopping("rcu_torture_reader");
1263 * Print torture statistics. Caller must ensure that there is only
1264 * one call to this function at a given time!!! This is normally
1265 * accomplished by relying on the module system to only have one copy
1266 * of the module loaded, and then by giving the rcu_torture_stats
1267 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1268 * thread is not running).
1271 rcu_torture_stats_print(void)
1275 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1276 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1277 static unsigned long rtcv_snap = ULONG_MAX;
1278 struct task_struct *wtp;
1280 for_each_possible_cpu(cpu) {
1281 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1282 pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
1283 batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
1286 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
1287 if (pipesummary[i] != 0)
1291 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1292 pr_cont("rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
1293 rcu_torture_current,
1294 rcu_torture_current_version,
1295 list_empty(&rcu_torture_freelist),
1296 atomic_read(&n_rcu_torture_alloc),
1297 atomic_read(&n_rcu_torture_alloc_fail),
1298 atomic_read(&n_rcu_torture_free));
1299 pr_cont("rtmbe: %d rtbe: %ld rtbke: %ld rtbre: %ld ",
1300 atomic_read(&n_rcu_torture_mberror),
1301 n_rcu_torture_barrier_error,
1302 n_rcu_torture_boost_ktrerror,
1303 n_rcu_torture_boost_rterror);
1304 pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
1305 n_rcu_torture_boost_failure,
1306 n_rcu_torture_boosts,
1307 n_rcu_torture_timers);
1308 torture_onoff_stats();
1309 pr_cont("barrier: %ld/%ld:%ld ",
1310 n_barrier_successes,
1312 n_rcu_torture_barrier_error);
1313 pr_cont("cbflood: %ld\n", atomic_long_read(&n_cbfloods));
1315 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1316 if (atomic_read(&n_rcu_torture_mberror) != 0 ||
1317 n_rcu_torture_barrier_error != 0 ||
1318 n_rcu_torture_boost_ktrerror != 0 ||
1319 n_rcu_torture_boost_rterror != 0 ||
1320 n_rcu_torture_boost_failure != 0 ||
1322 pr_cont("%s", "!!! ");
1323 atomic_inc(&n_rcu_torture_error);
1326 pr_cont("Reader Pipe: ");
1327 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1328 pr_cont(" %ld", pipesummary[i]);
1331 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1332 pr_cont("Reader Batch: ");
1333 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1334 pr_cont(" %ld", batchsummary[i]);
1337 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1338 pr_cont("Free-Block Circulation: ");
1339 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1340 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
1346 if (rtcv_snap == rcu_torture_current_version &&
1347 rcu_torture_current != NULL) {
1348 int __maybe_unused flags = 0;
1349 unsigned long __maybe_unused gpnum = 0;
1350 unsigned long __maybe_unused completed = 0;
1352 rcutorture_get_gp_data(cur_ops->ttype,
1353 &flags, &gpnum, &completed);
1354 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp,
1355 &flags, &gpnum, &completed);
1356 wtp = READ_ONCE(writer_task);
1357 pr_alert("??? Writer stall state %s(%d) g%lu c%lu f%#x ->state %#lx\n",
1358 rcu_torture_writer_state_getname(),
1359 rcu_torture_writer_state,
1360 gpnum, completed, flags,
1361 wtp == NULL ? ~0UL : wtp->state);
1362 show_rcu_gp_kthreads();
1363 rcu_ftrace_dump(DUMP_ALL);
1365 rtcv_snap = rcu_torture_current_version;
1369 * Periodically prints torture statistics, if periodic statistics printing
1370 * was specified via the stat_interval module parameter.
1373 rcu_torture_stats(void *arg)
1375 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1377 schedule_timeout_interruptible(stat_interval * HZ);
1378 rcu_torture_stats_print();
1379 torture_shutdown_absorb("rcu_torture_stats");
1380 } while (!torture_must_stop());
1381 torture_kthread_stopping("rcu_torture_stats");
1386 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1388 pr_alert("%s" TORTURE_FLAG
1389 "--- %s: nreaders=%d nfakewriters=%d "
1390 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1391 "shuffle_interval=%d stutter=%d irqreader=%d "
1392 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1393 "test_boost=%d/%d test_boost_interval=%d "
1394 "test_boost_duration=%d shutdown_secs=%d "
1395 "stall_cpu=%d stall_cpu_holdoff=%d "
1397 "onoff_interval=%d onoff_holdoff=%d\n",
1398 torture_type, tag, nrealreaders, nfakewriters,
1399 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1400 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1401 test_boost, cur_ops->can_boost,
1402 test_boost_interval, test_boost_duration, shutdown_secs,
1403 stall_cpu, stall_cpu_holdoff,
1405 onoff_interval, onoff_holdoff);
1408 static int rcutorture_booster_cleanup(unsigned int cpu)
1410 struct task_struct *t;
1412 if (boost_tasks[cpu] == NULL)
1414 mutex_lock(&boost_mutex);
1415 t = boost_tasks[cpu];
1416 boost_tasks[cpu] = NULL;
1417 mutex_unlock(&boost_mutex);
1419 /* This must be outside of the mutex, otherwise deadlock! */
1420 torture_stop_kthread(rcu_torture_boost, t);
1424 static int rcutorture_booster_init(unsigned int cpu)
1428 if (boost_tasks[cpu] != NULL)
1429 return 0; /* Already created, nothing more to do. */
1431 /* Don't allow time recalculation while creating a new task. */
1432 mutex_lock(&boost_mutex);
1433 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
1434 boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
1436 "rcu_torture_boost");
1437 if (IS_ERR(boost_tasks[cpu])) {
1438 retval = PTR_ERR(boost_tasks[cpu]);
1439 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
1440 n_rcu_torture_boost_ktrerror++;
1441 boost_tasks[cpu] = NULL;
1442 mutex_unlock(&boost_mutex);
1445 kthread_bind(boost_tasks[cpu], cpu);
1446 wake_up_process(boost_tasks[cpu]);
1447 mutex_unlock(&boost_mutex);
1452 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
1453 * induces a CPU stall for the time specified by stall_cpu.
1455 static int rcu_torture_stall(void *args)
1457 unsigned long stop_at;
1459 VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
1460 if (stall_cpu_holdoff > 0) {
1461 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
1462 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
1463 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
1465 if (!kthread_should_stop()) {
1466 stop_at = get_seconds() + stall_cpu;
1467 /* RCU CPU stall is expected behavior in following code. */
1468 pr_alert("rcu_torture_stall start.\n");
1471 while (ULONG_CMP_LT(get_seconds(), stop_at))
1472 continue; /* Induce RCU CPU stall warning. */
1475 pr_alert("rcu_torture_stall end.\n");
1477 torture_shutdown_absorb("rcu_torture_stall");
1478 while (!kthread_should_stop())
1479 schedule_timeout_interruptible(10 * HZ);
1483 /* Spawn CPU-stall kthread, if stall_cpu specified. */
1484 static int __init rcu_torture_stall_init(void)
1488 return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
1491 /* Callback function for RCU barrier testing. */
1492 static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
1494 atomic_inc(&barrier_cbs_invoked);
1497 /* kthread function to register callbacks used to test RCU barriers. */
1498 static int rcu_torture_barrier_cbs(void *arg)
1500 long myid = (long)arg;
1503 struct rcu_head rcu;
1505 init_rcu_head_on_stack(&rcu);
1506 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
1507 set_user_nice(current, MAX_NICE);
1509 wait_event(barrier_cbs_wq[myid],
1511 smp_load_acquire(&barrier_phase)) != lastphase ||
1512 torture_must_stop());
1513 lastphase = newphase;
1514 if (torture_must_stop())
1517 * The above smp_load_acquire() ensures barrier_phase load
1518 * is ordered before the following ->call().
1520 local_irq_disable(); /* Just to test no-irq call_rcu(). */
1521 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
1523 if (atomic_dec_and_test(&barrier_cbs_count))
1524 wake_up(&barrier_wq);
1525 } while (!torture_must_stop());
1526 if (cur_ops->cb_barrier != NULL)
1527 cur_ops->cb_barrier();
1528 destroy_rcu_head_on_stack(&rcu);
1529 torture_kthread_stopping("rcu_torture_barrier_cbs");
1533 /* kthread function to drive and coordinate RCU barrier testing. */
1534 static int rcu_torture_barrier(void *arg)
1538 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
1540 atomic_set(&barrier_cbs_invoked, 0);
1541 atomic_set(&barrier_cbs_count, n_barrier_cbs);
1542 /* Ensure barrier_phase ordered after prior assignments. */
1543 smp_store_release(&barrier_phase, !barrier_phase);
1544 for (i = 0; i < n_barrier_cbs; i++)
1545 wake_up(&barrier_cbs_wq[i]);
1546 wait_event(barrier_wq,
1547 atomic_read(&barrier_cbs_count) == 0 ||
1548 torture_must_stop());
1549 if (torture_must_stop())
1551 n_barrier_attempts++;
1552 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
1553 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
1554 n_rcu_torture_barrier_error++;
1555 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
1556 atomic_read(&barrier_cbs_invoked),
1560 n_barrier_successes++;
1561 schedule_timeout_interruptible(HZ / 10);
1562 } while (!torture_must_stop());
1563 torture_kthread_stopping("rcu_torture_barrier");
1567 /* Initialize RCU barrier testing. */
1568 static int rcu_torture_barrier_init(void)
1573 if (n_barrier_cbs <= 0)
1575 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
1576 pr_alert("%s" TORTURE_FLAG
1577 " Call or barrier ops missing for %s,\n",
1578 torture_type, cur_ops->name);
1579 pr_alert("%s" TORTURE_FLAG
1580 " RCU barrier testing omitted from run.\n",
1584 atomic_set(&barrier_cbs_count, 0);
1585 atomic_set(&barrier_cbs_invoked, 0);
1587 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_tasks[0]),
1590 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_wq[0]),
1592 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
1594 for (i = 0; i < n_barrier_cbs; i++) {
1595 init_waitqueue_head(&barrier_cbs_wq[i]);
1596 ret = torture_create_kthread(rcu_torture_barrier_cbs,
1598 barrier_cbs_tasks[i]);
1602 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
1605 /* Clean up after RCU barrier testing. */
1606 static void rcu_torture_barrier_cleanup(void)
1610 torture_stop_kthread(rcu_torture_barrier, barrier_task);
1611 if (barrier_cbs_tasks != NULL) {
1612 for (i = 0; i < n_barrier_cbs; i++)
1613 torture_stop_kthread(rcu_torture_barrier_cbs,
1614 barrier_cbs_tasks[i]);
1615 kfree(barrier_cbs_tasks);
1616 barrier_cbs_tasks = NULL;
1618 if (barrier_cbs_wq != NULL) {
1619 kfree(barrier_cbs_wq);
1620 barrier_cbs_wq = NULL;
1624 static enum cpuhp_state rcutor_hp;
1627 rcu_torture_cleanup(void)
1631 rcutorture_record_test_transition();
1632 if (torture_cleanup_begin()) {
1633 if (cur_ops->cb_barrier != NULL)
1634 cur_ops->cb_barrier();
1638 rcu_torture_barrier_cleanup();
1639 torture_stop_kthread(rcu_torture_stall, stall_task);
1640 torture_stop_kthread(rcu_torture_writer, writer_task);
1643 for (i = 0; i < nrealreaders; i++)
1644 torture_stop_kthread(rcu_torture_reader,
1646 kfree(reader_tasks);
1648 rcu_torture_current = NULL;
1650 if (fakewriter_tasks) {
1651 for (i = 0; i < nfakewriters; i++) {
1652 torture_stop_kthread(rcu_torture_fakewriter,
1653 fakewriter_tasks[i]);
1655 kfree(fakewriter_tasks);
1656 fakewriter_tasks = NULL;
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("rcutorture: duplicated callback was invoked.\n");
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("rcutorture: WARN: Duplicate call_rcu() test starting.\n");
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("rcutorture: WARN: Duplicate call_rcu() test complete.\n");
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("rcutorture: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n");
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, RCUTORTURE_TASKS_OPS
1755 if (!torture_init_begin(torture_type, verbose, &torture_runnable))
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 = kzalloc(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 = kzalloc(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 * HZ);
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,
1932 rcutorture_record_test_transition();
1938 rcu_torture_cleanup();
1942 module_init(rcu_torture_init);
1943 module_exit(rcu_torture_cleanup);