1 // SPDX-License-Identifier: GPL-2.0+
3 * Read-Copy Update module-based torture test facility
5 * Copyright (C) IBM Corporation, 2005, 2006
7 * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
8 * Josh Triplett <josh@joshtriplett.org>
10 * See also: Documentation/RCU/torture.txt
13 #define pr_fmt(fmt) fmt
15 #include <linux/types.h>
16 #include <linux/kernel.h>
17 #include <linux/init.h>
18 #include <linux/module.h>
19 #include <linux/kthread.h>
20 #include <linux/err.h>
21 #include <linux/spinlock.h>
22 #include <linux/smp.h>
23 #include <linux/rcupdate.h>
24 #include <linux/interrupt.h>
25 #include <linux/sched/signal.h>
26 #include <uapi/linux/sched/types.h>
27 #include <linux/atomic.h>
28 #include <linux/bitops.h>
29 #include <linux/completion.h>
30 #include <linux/moduleparam.h>
31 #include <linux/percpu.h>
32 #include <linux/notifier.h>
33 #include <linux/reboot.h>
34 #include <linux/freezer.h>
35 #include <linux/cpu.h>
36 #include <linux/delay.h>
37 #include <linux/stat.h>
38 #include <linux/srcu.h>
39 #include <linux/slab.h>
40 #include <linux/trace_clock.h>
41 #include <asm/byteorder.h>
42 #include <linux/torture.h>
43 #include <linux/vmalloc.h>
44 #include <linux/sched/debug.h>
45 #include <linux/sched/sysctl.h>
46 #include <linux/oom.h>
47 #include <linux/tick.h>
51 MODULE_LICENSE("GPL");
52 MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
55 /* Bits for ->extendables field, extendables param, and related definitions. */
56 #define RCUTORTURE_RDR_SHIFT 8 /* Put SRCU index in upper bits. */
57 #define RCUTORTURE_RDR_MASK ((1 << RCUTORTURE_RDR_SHIFT) - 1)
58 #define RCUTORTURE_RDR_BH 0x01 /* Extend readers by disabling bh. */
59 #define RCUTORTURE_RDR_IRQ 0x02 /* ... disabling interrupts. */
60 #define RCUTORTURE_RDR_PREEMPT 0x04 /* ... disabling preemption. */
61 #define RCUTORTURE_RDR_RBH 0x08 /* ... rcu_read_lock_bh(). */
62 #define RCUTORTURE_RDR_SCHED 0x10 /* ... rcu_read_lock_sched(). */
63 #define RCUTORTURE_RDR_RCU 0x20 /* ... entering another RCU reader. */
64 #define RCUTORTURE_RDR_NBITS 6 /* Number of bits defined above. */
65 #define RCUTORTURE_MAX_EXTEND \
66 (RCUTORTURE_RDR_BH | RCUTORTURE_RDR_IRQ | RCUTORTURE_RDR_PREEMPT | \
67 RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED)
68 #define RCUTORTURE_RDR_MAX_LOOPS 0x7 /* Maximum reader extensions. */
69 /* Must be power of two minus one. */
70 #define RCUTORTURE_RDR_MAX_SEGS (RCUTORTURE_RDR_MAX_LOOPS + 3)
72 torture_param(int, extendables, RCUTORTURE_MAX_EXTEND,
73 "Extend readers by disabling bh (1), irqs (2), or preempt (4)");
74 torture_param(int, fqs_duration, 0,
75 "Duration of fqs bursts (us), 0 to disable");
76 torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
77 torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
78 torture_param(bool, fwd_progress, 1, "Test grace-period forward progress");
79 torture_param(int, fwd_progress_div, 4, "Fraction of CPU stall to wait");
80 torture_param(int, fwd_progress_holdoff, 60,
81 "Time between forward-progress tests (s)");
82 torture_param(bool, fwd_progress_need_resched, 1,
83 "Hide cond_resched() behind need_resched()");
84 torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
85 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
86 torture_param(bool, gp_normal, false,
87 "Use normal (non-expedited) GP wait primitives");
88 torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
89 torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
90 torture_param(int, n_barrier_cbs, 0,
91 "# of callbacks/kthreads for barrier testing");
92 torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
93 torture_param(int, nreaders, -1, "Number of RCU reader threads");
94 torture_param(int, object_debug, 0,
95 "Enable debug-object double call_rcu() testing");
96 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
97 torture_param(int, onoff_interval, 0,
98 "Time between CPU hotplugs (jiffies), 0=disable");
99 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
100 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
101 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
102 torture_param(int, stall_cpu_holdoff, 10,
103 "Time to wait before starting stall (s).");
104 torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling.");
105 torture_param(int, stat_interval, 60,
106 "Number of seconds between stats printk()s");
107 torture_param(int, stutter, 5, "Number of seconds to run/halt test");
108 torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
109 torture_param(int, test_boost_duration, 4,
110 "Duration of each boost test, seconds.");
111 torture_param(int, test_boost_interval, 7,
112 "Interval between boost tests, seconds.");
113 torture_param(bool, test_no_idle_hz, true,
114 "Test support for tickless idle CPUs");
115 torture_param(int, verbose, 1,
116 "Enable verbose debugging printk()s");
118 static char *torture_type = "rcu";
119 module_param(torture_type, charp, 0444);
120 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, srcu, ...)");
122 static int nrealreaders;
123 static struct task_struct *writer_task;
124 static struct task_struct **fakewriter_tasks;
125 static struct task_struct **reader_tasks;
126 static struct task_struct *stats_task;
127 static struct task_struct *fqs_task;
128 static struct task_struct *boost_tasks[NR_CPUS];
129 static struct task_struct *stall_task;
130 static struct task_struct *fwd_prog_task;
131 static struct task_struct **barrier_cbs_tasks;
132 static struct task_struct *barrier_task;
134 #define RCU_TORTURE_PIPE_LEN 10
137 struct rcu_head rtort_rcu;
138 int rtort_pipe_count;
139 struct list_head rtort_free;
143 static LIST_HEAD(rcu_torture_freelist);
144 static struct rcu_torture __rcu *rcu_torture_current;
145 static unsigned long rcu_torture_current_version;
146 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
147 static DEFINE_SPINLOCK(rcu_torture_lock);
148 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count);
149 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch);
150 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
151 static atomic_t n_rcu_torture_alloc;
152 static atomic_t n_rcu_torture_alloc_fail;
153 static atomic_t n_rcu_torture_free;
154 static atomic_t n_rcu_torture_mberror;
155 static atomic_t n_rcu_torture_error;
156 static long n_rcu_torture_barrier_error;
157 static long n_rcu_torture_boost_ktrerror;
158 static long n_rcu_torture_boost_rterror;
159 static long n_rcu_torture_boost_failure;
160 static long n_rcu_torture_boosts;
161 static atomic_long_t n_rcu_torture_timers;
162 static long n_barrier_attempts;
163 static long n_barrier_successes; /* did rcu_barrier test succeed? */
164 static struct list_head rcu_torture_removed;
165 static unsigned long shutdown_jiffies;
167 static int rcu_torture_writer_state;
168 #define RTWS_FIXED_DELAY 0
170 #define RTWS_REPLACE 2
171 #define RTWS_DEF_FREE 3
172 #define RTWS_EXP_SYNC 4
173 #define RTWS_COND_GET 5
174 #define RTWS_COND_SYNC 6
176 #define RTWS_STUTTER 8
177 #define RTWS_STOPPING 9
178 static const char * const rcu_torture_writer_state_names[] = {
191 /* Record reader segment types and duration for first failing read. */
194 unsigned long rt_delay_jiffies;
195 unsigned long rt_delay_ms;
196 unsigned long rt_delay_us;
199 static int err_segs_recorded;
200 static struct rt_read_seg err_segs[RCUTORTURE_RDR_MAX_SEGS];
201 static int rt_read_nsegs;
203 static const char *rcu_torture_writer_state_getname(void)
205 unsigned int i = READ_ONCE(rcu_torture_writer_state);
207 if (i >= ARRAY_SIZE(rcu_torture_writer_state_names))
209 return rcu_torture_writer_state_names[i];
212 #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
213 #define rcu_can_boost() 1
214 #else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
215 #define rcu_can_boost() 0
216 #endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
218 #ifdef CONFIG_RCU_TRACE
219 static u64 notrace rcu_trace_clock_local(void)
221 u64 ts = trace_clock_local();
223 (void)do_div(ts, NSEC_PER_USEC);
226 #else /* #ifdef CONFIG_RCU_TRACE */
227 static u64 notrace rcu_trace_clock_local(void)
231 #endif /* #else #ifdef CONFIG_RCU_TRACE */
234 * Stop aggressive CPU-hog tests a bit before the end of the test in order
235 * to avoid interfering with test shutdown.
237 static bool shutdown_time_arrived(void)
239 return shutdown_secs && time_after(jiffies, shutdown_jiffies - 30 * HZ);
242 static unsigned long boost_starttime; /* jiffies of next boost test start. */
243 static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
244 /* and boost task create/destroy. */
245 static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
246 static bool barrier_phase; /* Test phase. */
247 static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
248 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
249 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
251 static bool rcu_fwd_cb_nodelay; /* Short rcu_torture_delay() delays. */
254 * Allocate an element from the rcu_tortures pool.
256 static struct rcu_torture *
257 rcu_torture_alloc(void)
261 spin_lock_bh(&rcu_torture_lock);
262 if (list_empty(&rcu_torture_freelist)) {
263 atomic_inc(&n_rcu_torture_alloc_fail);
264 spin_unlock_bh(&rcu_torture_lock);
267 atomic_inc(&n_rcu_torture_alloc);
268 p = rcu_torture_freelist.next;
270 spin_unlock_bh(&rcu_torture_lock);
271 return container_of(p, struct rcu_torture, rtort_free);
275 * Free an element to the rcu_tortures pool.
278 rcu_torture_free(struct rcu_torture *p)
280 atomic_inc(&n_rcu_torture_free);
281 spin_lock_bh(&rcu_torture_lock);
282 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
283 spin_unlock_bh(&rcu_torture_lock);
287 * Operations vector for selecting different types of tests.
290 struct rcu_torture_ops {
293 void (*cleanup)(void);
294 int (*readlock)(void);
295 void (*read_delay)(struct torture_random_state *rrsp,
296 struct rt_read_seg *rtrsp);
297 void (*readunlock)(int idx);
298 unsigned long (*get_gp_seq)(void);
299 unsigned long (*gp_diff)(unsigned long new, unsigned long old);
300 void (*deferred_free)(struct rcu_torture *p);
302 void (*exp_sync)(void);
303 unsigned long (*get_state)(void);
304 void (*cond_sync)(unsigned long oldstate);
305 call_rcu_func_t call;
306 void (*cb_barrier)(void);
309 int (*stall_dur)(void);
317 static struct rcu_torture_ops *cur_ops;
320 * Definitions for rcu torture testing.
323 static int rcu_torture_read_lock(void) __acquires(RCU)
330 rcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
332 unsigned long started;
333 unsigned long completed;
334 const unsigned long shortdelay_us = 200;
335 unsigned long longdelay_ms = 300;
336 unsigned long long ts;
338 /* We want a short delay sometimes to make a reader delay the grace
339 * period, and we want a long delay occasionally to trigger
340 * force_quiescent_state. */
342 if (!rcu_fwd_cb_nodelay &&
343 !(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) {
344 started = cur_ops->get_gp_seq();
345 ts = rcu_trace_clock_local();
346 if (preempt_count() & (SOFTIRQ_MASK | HARDIRQ_MASK))
347 longdelay_ms = 5; /* Avoid triggering BH limits. */
348 mdelay(longdelay_ms);
349 rtrsp->rt_delay_ms = longdelay_ms;
350 completed = cur_ops->get_gp_seq();
351 do_trace_rcu_torture_read(cur_ops->name, NULL, ts,
354 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) {
355 udelay(shortdelay_us);
356 rtrsp->rt_delay_us = shortdelay_us;
358 if (!preempt_count() &&
359 !(torture_random(rrsp) % (nrealreaders * 500))) {
360 torture_preempt_schedule(); /* QS only if preemptible. */
361 rtrsp->rt_preempted = true;
365 static void rcu_torture_read_unlock(int idx) __releases(RCU)
371 * Update callback in the pipe. This should be invoked after a grace period.
374 rcu_torture_pipe_update_one(struct rcu_torture *rp)
378 i = rp->rtort_pipe_count;
379 if (i > RCU_TORTURE_PIPE_LEN)
380 i = RCU_TORTURE_PIPE_LEN;
381 atomic_inc(&rcu_torture_wcount[i]);
382 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
383 rp->rtort_mbtest = 0;
390 * Update all callbacks in the pipe. Suitable for synchronous grace-period
394 rcu_torture_pipe_update(struct rcu_torture *old_rp)
396 struct rcu_torture *rp;
397 struct rcu_torture *rp1;
400 list_add(&old_rp->rtort_free, &rcu_torture_removed);
401 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
402 if (rcu_torture_pipe_update_one(rp)) {
403 list_del(&rp->rtort_free);
404 rcu_torture_free(rp);
410 rcu_torture_cb(struct rcu_head *p)
412 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
414 if (torture_must_stop_irq()) {
415 /* Test is ending, just drop callbacks on the floor. */
416 /* The next initialization will pick up the pieces. */
419 if (rcu_torture_pipe_update_one(rp))
420 rcu_torture_free(rp);
422 cur_ops->deferred_free(rp);
425 static unsigned long rcu_no_completed(void)
430 static void rcu_torture_deferred_free(struct rcu_torture *p)
432 call_rcu(&p->rtort_rcu, rcu_torture_cb);
435 static void rcu_sync_torture_init(void)
437 INIT_LIST_HEAD(&rcu_torture_removed);
440 static struct rcu_torture_ops rcu_ops = {
442 .init = rcu_sync_torture_init,
443 .readlock = rcu_torture_read_lock,
444 .read_delay = rcu_read_delay,
445 .readunlock = rcu_torture_read_unlock,
446 .get_gp_seq = rcu_get_gp_seq,
447 .gp_diff = rcu_seq_diff,
448 .deferred_free = rcu_torture_deferred_free,
449 .sync = synchronize_rcu,
450 .exp_sync = synchronize_rcu_expedited,
451 .get_state = get_state_synchronize_rcu,
452 .cond_sync = cond_synchronize_rcu,
454 .cb_barrier = rcu_barrier,
455 .fqs = rcu_force_quiescent_state,
457 .stall_dur = rcu_jiffies_till_stall_check,
459 .can_boost = rcu_can_boost(),
460 .extendables = RCUTORTURE_MAX_EXTEND,
465 * Don't even think about trying any of these in real life!!!
466 * The names includes "busted", and they really means it!
467 * The only purpose of these functions is to provide a buggy RCU
468 * implementation to make sure that rcutorture correctly emits
469 * buggy-RCU error messages.
471 static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
473 /* This is a deliberate bug for testing purposes only! */
474 rcu_torture_cb(&p->rtort_rcu);
477 static void synchronize_rcu_busted(void)
479 /* This is a deliberate bug for testing purposes only! */
483 call_rcu_busted(struct rcu_head *head, rcu_callback_t func)
485 /* This is a deliberate bug for testing purposes only! */
489 static struct rcu_torture_ops rcu_busted_ops = {
490 .ttype = INVALID_RCU_FLAVOR,
491 .init = rcu_sync_torture_init,
492 .readlock = rcu_torture_read_lock,
493 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
494 .readunlock = rcu_torture_read_unlock,
495 .get_gp_seq = rcu_no_completed,
496 .deferred_free = rcu_busted_torture_deferred_free,
497 .sync = synchronize_rcu_busted,
498 .exp_sync = synchronize_rcu_busted,
499 .call = call_rcu_busted,
508 * Definitions for srcu torture testing.
511 DEFINE_STATIC_SRCU(srcu_ctl);
512 static struct srcu_struct srcu_ctld;
513 static struct srcu_struct *srcu_ctlp = &srcu_ctl;
515 static int srcu_torture_read_lock(void) __acquires(srcu_ctlp)
517 return srcu_read_lock(srcu_ctlp);
521 srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
524 const long uspertick = 1000000 / HZ;
525 const long longdelay = 10;
527 /* We want there to be long-running readers, but not all the time. */
529 delay = torture_random(rrsp) %
530 (nrealreaders * 2 * longdelay * uspertick);
531 if (!delay && in_task()) {
532 schedule_timeout_interruptible(longdelay);
533 rtrsp->rt_delay_jiffies = longdelay;
535 rcu_read_delay(rrsp, rtrsp);
539 static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp)
541 srcu_read_unlock(srcu_ctlp, idx);
544 static unsigned long srcu_torture_completed(void)
546 return srcu_batches_completed(srcu_ctlp);
549 static void srcu_torture_deferred_free(struct rcu_torture *rp)
551 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
554 static void srcu_torture_synchronize(void)
556 synchronize_srcu(srcu_ctlp);
559 static void srcu_torture_call(struct rcu_head *head,
562 call_srcu(srcu_ctlp, head, func);
565 static void srcu_torture_barrier(void)
567 srcu_barrier(srcu_ctlp);
570 static void srcu_torture_stats(void)
572 srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG);
575 static void srcu_torture_synchronize_expedited(void)
577 synchronize_srcu_expedited(srcu_ctlp);
580 static struct rcu_torture_ops srcu_ops = {
581 .ttype = SRCU_FLAVOR,
582 .init = rcu_sync_torture_init,
583 .readlock = srcu_torture_read_lock,
584 .read_delay = srcu_read_delay,
585 .readunlock = srcu_torture_read_unlock,
586 .get_gp_seq = 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,
597 static void srcu_torture_init(void)
599 rcu_sync_torture_init();
600 WARN_ON(init_srcu_struct(&srcu_ctld));
601 srcu_ctlp = &srcu_ctld;
604 static void srcu_torture_cleanup(void)
606 cleanup_srcu_struct(&srcu_ctld);
607 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
610 /* As above, but dynamically allocated. */
611 static struct rcu_torture_ops srcud_ops = {
612 .ttype = SRCU_FLAVOR,
613 .init = srcu_torture_init,
614 .cleanup = srcu_torture_cleanup,
615 .readlock = srcu_torture_read_lock,
616 .read_delay = srcu_read_delay,
617 .readunlock = srcu_torture_read_unlock,
618 .get_gp_seq = 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 /* As above, but broken due to inappropriate reader extension. */
630 static struct rcu_torture_ops busted_srcud_ops = {
631 .ttype = SRCU_FLAVOR,
632 .init = srcu_torture_init,
633 .cleanup = srcu_torture_cleanup,
634 .readlock = srcu_torture_read_lock,
635 .read_delay = rcu_read_delay,
636 .readunlock = srcu_torture_read_unlock,
637 .get_gp_seq = srcu_torture_completed,
638 .deferred_free = srcu_torture_deferred_free,
639 .sync = srcu_torture_synchronize,
640 .exp_sync = srcu_torture_synchronize_expedited,
641 .call = srcu_torture_call,
642 .cb_barrier = srcu_torture_barrier,
643 .stats = srcu_torture_stats,
645 .extendables = RCUTORTURE_MAX_EXTEND,
646 .name = "busted_srcud"
650 * Definitions for RCU-tasks torture testing.
653 static int tasks_torture_read_lock(void)
658 static void tasks_torture_read_unlock(int idx)
662 static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
664 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
667 static struct rcu_torture_ops tasks_ops = {
668 .ttype = RCU_TASKS_FLAVOR,
669 .init = rcu_sync_torture_init,
670 .readlock = tasks_torture_read_lock,
671 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
672 .readunlock = tasks_torture_read_unlock,
673 .get_gp_seq = rcu_no_completed,
674 .deferred_free = rcu_tasks_torture_deferred_free,
675 .sync = synchronize_rcu_tasks,
676 .exp_sync = synchronize_rcu_tasks,
677 .call = call_rcu_tasks,
678 .cb_barrier = rcu_barrier_tasks,
687 * Definitions for trivial CONFIG_PREEMPT=n-only torture testing.
688 * This implementation does not necessarily work well with CPU hotplug.
691 static void synchronize_rcu_trivial(void)
695 for_each_online_cpu(cpu) {
696 rcutorture_sched_setaffinity(current->pid, cpumask_of(cpu));
697 WARN_ON_ONCE(raw_smp_processor_id() != cpu);
701 static int rcu_torture_read_lock_trivial(void) __acquires(RCU)
707 static void rcu_torture_read_unlock_trivial(int idx) __releases(RCU)
712 static struct rcu_torture_ops trivial_ops = {
713 .ttype = RCU_TRIVIAL_FLAVOR,
714 .init = rcu_sync_torture_init,
715 .readlock = rcu_torture_read_lock_trivial,
716 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
717 .readunlock = rcu_torture_read_unlock_trivial,
718 .get_gp_seq = rcu_no_completed,
719 .sync = synchronize_rcu_trivial,
720 .exp_sync = synchronize_rcu_trivial,
727 static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old)
729 if (!cur_ops->gp_diff)
731 return cur_ops->gp_diff(new, old);
734 static bool __maybe_unused torturing_tasks(void)
736 return cur_ops == &tasks_ops;
740 * RCU torture priority-boost testing. Runs one real-time thread per
741 * CPU for moderate bursts, repeatedly registering RCU callbacks and
742 * spinning waiting for them to be invoked. If a given callback takes
743 * too long to be invoked, we assume that priority inversion has occurred.
746 struct rcu_boost_inflight {
751 static void rcu_torture_boost_cb(struct rcu_head *head)
753 struct rcu_boost_inflight *rbip =
754 container_of(head, struct rcu_boost_inflight, rcu);
756 /* Ensure RCU-core accesses precede clearing ->inflight */
757 smp_store_release(&rbip->inflight, 0);
760 static int old_rt_runtime = -1;
762 static void rcu_torture_disable_rt_throttle(void)
765 * Disable RT throttling so that rcutorture's boost threads don't get
766 * throttled. Only possible if rcutorture is built-in otherwise the
767 * user should manually do this by setting the sched_rt_period_us and
768 * sched_rt_runtime sysctls.
770 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime != -1)
773 old_rt_runtime = sysctl_sched_rt_runtime;
774 sysctl_sched_rt_runtime = -1;
777 static void rcu_torture_enable_rt_throttle(void)
779 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime == -1)
782 sysctl_sched_rt_runtime = old_rt_runtime;
786 static bool rcu_torture_boost_failed(unsigned long start, unsigned long end)
788 if (end - start > test_boost_duration * HZ - HZ / 2) {
789 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
790 n_rcu_torture_boost_failure++;
792 return true; /* failed */
795 return false; /* passed */
798 static int rcu_torture_boost(void *arg)
800 unsigned long call_rcu_time;
801 unsigned long endtime;
802 unsigned long oldstarttime;
803 struct rcu_boost_inflight rbi = { .inflight = 0 };
804 struct sched_param sp;
806 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
808 /* Set real-time priority. */
809 sp.sched_priority = 1;
810 if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
811 VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!");
812 n_rcu_torture_boost_rterror++;
815 init_rcu_head_on_stack(&rbi.rcu);
816 /* Each pass through the following loop does one boost-test cycle. */
818 /* Track if the test failed already in this test interval? */
821 /* Increment n_rcu_torture_boosts once per boost-test */
822 while (!kthread_should_stop()) {
823 if (mutex_trylock(&boost_mutex)) {
824 n_rcu_torture_boosts++;
825 mutex_unlock(&boost_mutex);
828 schedule_timeout_uninterruptible(1);
830 if (kthread_should_stop())
833 /* Wait for the next test interval. */
834 oldstarttime = boost_starttime;
835 while (ULONG_CMP_LT(jiffies, oldstarttime)) {
836 schedule_timeout_interruptible(oldstarttime - jiffies);
837 stutter_wait("rcu_torture_boost");
838 if (torture_must_stop())
842 /* Do one boost-test interval. */
843 endtime = oldstarttime + test_boost_duration * HZ;
844 call_rcu_time = jiffies;
845 while (ULONG_CMP_LT(jiffies, endtime)) {
846 /* If we don't have a callback in flight, post one. */
847 if (!smp_load_acquire(&rbi.inflight)) {
848 /* RCU core before ->inflight = 1. */
849 smp_store_release(&rbi.inflight, 1);
850 call_rcu(&rbi.rcu, rcu_torture_boost_cb);
851 /* Check if the boost test failed */
853 rcu_torture_boost_failed(call_rcu_time,
855 call_rcu_time = jiffies;
857 stutter_wait("rcu_torture_boost");
858 if (torture_must_stop())
863 * If boost never happened, then inflight will always be 1, in
864 * this case the boost check would never happen in the above
865 * loop so do another one here.
867 if (!failed && smp_load_acquire(&rbi.inflight))
868 rcu_torture_boost_failed(call_rcu_time, jiffies);
871 * Set the start time of the next test interval.
872 * Yes, this is vulnerable to long delays, but such
873 * delays simply cause a false negative for the next
874 * interval. Besides, we are running at RT priority,
875 * so delays should be relatively rare.
877 while (oldstarttime == boost_starttime &&
878 !kthread_should_stop()) {
879 if (mutex_trylock(&boost_mutex)) {
880 boost_starttime = jiffies +
881 test_boost_interval * HZ;
882 mutex_unlock(&boost_mutex);
885 schedule_timeout_uninterruptible(1);
888 /* Go do the stutter. */
889 checkwait: stutter_wait("rcu_torture_boost");
890 } while (!torture_must_stop());
892 /* Clean up and exit. */
893 while (!kthread_should_stop() || smp_load_acquire(&rbi.inflight)) {
894 torture_shutdown_absorb("rcu_torture_boost");
895 schedule_timeout_uninterruptible(1);
897 destroy_rcu_head_on_stack(&rbi.rcu);
898 torture_kthread_stopping("rcu_torture_boost");
903 * RCU torture force-quiescent-state kthread. Repeatedly induces
904 * bursts of calls to force_quiescent_state(), increasing the probability
905 * of occurrence of some important types of race conditions.
908 rcu_torture_fqs(void *arg)
910 unsigned long fqs_resume_time;
911 int fqs_burst_remaining;
913 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
915 fqs_resume_time = jiffies + fqs_stutter * HZ;
916 while (ULONG_CMP_LT(jiffies, fqs_resume_time) &&
917 !kthread_should_stop()) {
918 schedule_timeout_interruptible(1);
920 fqs_burst_remaining = fqs_duration;
921 while (fqs_burst_remaining > 0 &&
922 !kthread_should_stop()) {
925 fqs_burst_remaining -= fqs_holdoff;
927 stutter_wait("rcu_torture_fqs");
928 } while (!torture_must_stop());
929 torture_kthread_stopping("rcu_torture_fqs");
934 * RCU torture writer kthread. Repeatedly substitutes a new structure
935 * for that pointed to by rcu_torture_current, freeing the old structure
936 * after a series of grace periods (the "pipeline").
939 rcu_torture_writer(void *arg)
941 bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
943 unsigned long gp_snap;
944 bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal;
945 bool gp_sync1 = gp_sync;
947 struct rcu_torture *rp;
948 struct rcu_torture *old_rp;
949 static DEFINE_TORTURE_RANDOM(rand);
950 int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC,
951 RTWS_COND_GET, RTWS_SYNC };
954 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
956 pr_alert("%s" TORTURE_FLAG
957 " GP expediting controlled from boot/sysfs for %s.\n",
958 torture_type, cur_ops->name);
960 /* Initialize synctype[] array. If none set, take default. */
961 if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync1)
962 gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true;
963 if (gp_cond1 && cur_ops->get_state && cur_ops->cond_sync) {
964 synctype[nsynctypes++] = RTWS_COND_GET;
965 pr_info("%s: Testing conditional GPs.\n", __func__);
966 } else if (gp_cond && (!cur_ops->get_state || !cur_ops->cond_sync)) {
967 pr_alert("%s: gp_cond without primitives.\n", __func__);
969 if (gp_exp1 && cur_ops->exp_sync) {
970 synctype[nsynctypes++] = RTWS_EXP_SYNC;
971 pr_info("%s: Testing expedited GPs.\n", __func__);
972 } else if (gp_exp && !cur_ops->exp_sync) {
973 pr_alert("%s: gp_exp without primitives.\n", __func__);
975 if (gp_normal1 && cur_ops->deferred_free) {
976 synctype[nsynctypes++] = RTWS_DEF_FREE;
977 pr_info("%s: Testing asynchronous GPs.\n", __func__);
978 } else if (gp_normal && !cur_ops->deferred_free) {
979 pr_alert("%s: gp_normal without primitives.\n", __func__);
981 if (gp_sync1 && cur_ops->sync) {
982 synctype[nsynctypes++] = RTWS_SYNC;
983 pr_info("%s: Testing normal GPs.\n", __func__);
984 } else if (gp_sync && !cur_ops->sync) {
985 pr_alert("%s: gp_sync without primitives.\n", __func__);
987 if (WARN_ONCE(nsynctypes == 0,
988 "rcu_torture_writer: No update-side primitives.\n")) {
990 * No updates primitives, so don't try updating.
991 * The resulting test won't be testing much, hence the
994 rcu_torture_writer_state = RTWS_STOPPING;
995 torture_kthread_stopping("rcu_torture_writer");
999 rcu_torture_writer_state = RTWS_FIXED_DELAY;
1000 schedule_timeout_uninterruptible(1);
1001 rp = rcu_torture_alloc();
1004 rp->rtort_pipe_count = 0;
1005 rcu_torture_writer_state = RTWS_DELAY;
1006 udelay(torture_random(&rand) & 0x3ff);
1007 rcu_torture_writer_state = RTWS_REPLACE;
1008 old_rp = rcu_dereference_check(rcu_torture_current,
1009 current == writer_task);
1010 rp->rtort_mbtest = 1;
1011 rcu_assign_pointer(rcu_torture_current, rp);
1012 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
1014 i = old_rp->rtort_pipe_count;
1015 if (i > RCU_TORTURE_PIPE_LEN)
1016 i = RCU_TORTURE_PIPE_LEN;
1017 atomic_inc(&rcu_torture_wcount[i]);
1018 old_rp->rtort_pipe_count++;
1019 switch (synctype[torture_random(&rand) % nsynctypes]) {
1021 rcu_torture_writer_state = RTWS_DEF_FREE;
1022 cur_ops->deferred_free(old_rp);
1025 rcu_torture_writer_state = RTWS_EXP_SYNC;
1026 cur_ops->exp_sync();
1027 rcu_torture_pipe_update(old_rp);
1030 rcu_torture_writer_state = RTWS_COND_GET;
1031 gp_snap = cur_ops->get_state();
1032 i = torture_random(&rand) % 16;
1034 schedule_timeout_interruptible(i);
1035 udelay(torture_random(&rand) % 1000);
1036 rcu_torture_writer_state = RTWS_COND_SYNC;
1037 cur_ops->cond_sync(gp_snap);
1038 rcu_torture_pipe_update(old_rp);
1041 rcu_torture_writer_state = RTWS_SYNC;
1043 rcu_torture_pipe_update(old_rp);
1050 WRITE_ONCE(rcu_torture_current_version,
1051 rcu_torture_current_version + 1);
1052 /* Cycle through nesting levels of rcu_expedite_gp() calls. */
1054 !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
1055 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
1056 if (expediting >= 0)
1059 rcu_unexpedite_gp();
1060 if (++expediting > 3)
1061 expediting = -expediting;
1062 } else if (!can_expedite) { /* Disabled during boot, recheck. */
1063 can_expedite = !rcu_gp_is_expedited() &&
1064 !rcu_gp_is_normal();
1066 rcu_torture_writer_state = RTWS_STUTTER;
1067 if (stutter_wait("rcu_torture_writer") &&
1068 !READ_ONCE(rcu_fwd_cb_nodelay) &&
1069 !cur_ops->slow_gps &&
1070 !torture_must_stop())
1071 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++)
1072 if (list_empty(&rcu_tortures[i].rtort_free) &&
1073 rcu_access_pointer(rcu_torture_current) !=
1075 rcu_ftrace_dump(DUMP_ALL);
1076 WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count);
1078 } while (!torture_must_stop());
1079 /* Reset expediting back to unexpedited. */
1081 expediting = -expediting;
1082 while (can_expedite && expediting++ < 0)
1083 rcu_unexpedite_gp();
1084 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
1086 pr_alert("%s" TORTURE_FLAG
1087 " Dynamic grace-period expediting was disabled.\n",
1089 rcu_torture_writer_state = RTWS_STOPPING;
1090 torture_kthread_stopping("rcu_torture_writer");
1095 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
1096 * delay between calls.
1099 rcu_torture_fakewriter(void *arg)
1101 DEFINE_TORTURE_RANDOM(rand);
1103 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1104 set_user_nice(current, MAX_NICE);
1107 schedule_timeout_uninterruptible(1 + torture_random(&rand)%10);
1108 udelay(torture_random(&rand) & 0x3ff);
1109 if (cur_ops->cb_barrier != NULL &&
1110 torture_random(&rand) % (nfakewriters * 8) == 0) {
1111 cur_ops->cb_barrier();
1112 } else if (gp_normal == gp_exp) {
1113 if (cur_ops->sync && torture_random(&rand) & 0x80)
1115 else if (cur_ops->exp_sync)
1116 cur_ops->exp_sync();
1117 } else if (gp_normal && cur_ops->sync) {
1119 } else if (cur_ops->exp_sync) {
1120 cur_ops->exp_sync();
1122 stutter_wait("rcu_torture_fakewriter");
1123 } while (!torture_must_stop());
1125 torture_kthread_stopping("rcu_torture_fakewriter");
1129 static void rcu_torture_timer_cb(struct rcu_head *rhp)
1135 * Do one extension of an RCU read-side critical section using the
1136 * current reader state in readstate (set to zero for initial entry
1137 * to extended critical section), set the new state as specified by
1138 * newstate (set to zero for final exit from extended critical section),
1139 * and random-number-generator state in trsp. If this is neither the
1140 * beginning or end of the critical section and if there was actually a
1141 * change, do a ->read_delay().
1143 static void rcutorture_one_extend(int *readstate, int newstate,
1144 struct torture_random_state *trsp,
1145 struct rt_read_seg *rtrsp)
1148 int idxold = *readstate;
1149 int statesnew = ~*readstate & newstate;
1150 int statesold = *readstate & ~newstate;
1152 WARN_ON_ONCE(idxold < 0);
1153 WARN_ON_ONCE((idxold >> RCUTORTURE_RDR_SHIFT) > 1);
1154 rtrsp->rt_readstate = newstate;
1156 /* First, put new protection in place to avoid critical-section gap. */
1157 if (statesnew & RCUTORTURE_RDR_BH)
1159 if (statesnew & RCUTORTURE_RDR_IRQ)
1160 local_irq_disable();
1161 if (statesnew & RCUTORTURE_RDR_PREEMPT)
1163 if (statesnew & RCUTORTURE_RDR_RBH)
1165 if (statesnew & RCUTORTURE_RDR_SCHED)
1166 rcu_read_lock_sched();
1167 if (statesnew & RCUTORTURE_RDR_RCU)
1168 idxnew = cur_ops->readlock() << RCUTORTURE_RDR_SHIFT;
1170 /* Next, remove old protection, irq first due to bh conflict. */
1171 if (statesold & RCUTORTURE_RDR_IRQ)
1173 if (statesold & RCUTORTURE_RDR_BH)
1175 if (statesold & RCUTORTURE_RDR_PREEMPT)
1177 if (statesold & RCUTORTURE_RDR_RBH)
1178 rcu_read_unlock_bh();
1179 if (statesold & RCUTORTURE_RDR_SCHED)
1180 rcu_read_unlock_sched();
1181 if (statesold & RCUTORTURE_RDR_RCU)
1182 cur_ops->readunlock(idxold >> RCUTORTURE_RDR_SHIFT);
1184 /* Delay if neither beginning nor end and there was a change. */
1185 if ((statesnew || statesold) && *readstate && newstate)
1186 cur_ops->read_delay(trsp, rtrsp);
1188 /* Update the reader state. */
1190 idxnew = idxold & ~RCUTORTURE_RDR_MASK;
1191 WARN_ON_ONCE(idxnew < 0);
1192 WARN_ON_ONCE((idxnew >> RCUTORTURE_RDR_SHIFT) > 1);
1193 *readstate = idxnew | newstate;
1194 WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT) < 0);
1195 WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT) > 1);
1198 /* Return the biggest extendables mask given current RCU and boot parameters. */
1199 static int rcutorture_extend_mask_max(void)
1203 WARN_ON_ONCE(extendables & ~RCUTORTURE_MAX_EXTEND);
1204 mask = extendables & RCUTORTURE_MAX_EXTEND & cur_ops->extendables;
1205 mask = mask | RCUTORTURE_RDR_RCU;
1209 /* Return a random protection state mask, but with at least one bit set. */
1211 rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp)
1213 int mask = rcutorture_extend_mask_max();
1214 unsigned long randmask1 = torture_random(trsp) >> 8;
1215 unsigned long randmask2 = randmask1 >> 3;
1217 WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT);
1218 /* Mostly only one bit (need preemption!), sometimes lots of bits. */
1219 if (!(randmask1 & 0x7))
1220 mask = mask & randmask2;
1222 mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS));
1223 /* Can't enable bh w/irq disabled. */
1224 if ((mask & RCUTORTURE_RDR_IRQ) &&
1225 ((!(mask & RCUTORTURE_RDR_BH) && (oldmask & RCUTORTURE_RDR_BH)) ||
1226 (!(mask & RCUTORTURE_RDR_RBH) && (oldmask & RCUTORTURE_RDR_RBH))))
1227 mask |= RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH;
1228 return mask ?: RCUTORTURE_RDR_RCU;
1232 * Do a randomly selected number of extensions of an existing RCU read-side
1235 static struct rt_read_seg *
1236 rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp,
1237 struct rt_read_seg *rtrsp)
1241 int mask = rcutorture_extend_mask_max();
1243 WARN_ON_ONCE(!*readstate); /* -Existing- RCU read-side critsect! */
1244 if (!((mask - 1) & mask))
1245 return rtrsp; /* Current RCU reader not extendable. */
1246 /* Bias towards larger numbers of loops. */
1247 i = (torture_random(trsp) >> 3);
1248 i = ((i | (i >> 3)) & RCUTORTURE_RDR_MAX_LOOPS) + 1;
1249 for (j = 0; j < i; j++) {
1250 mask = rcutorture_extend_mask(*readstate, trsp);
1251 rcutorture_one_extend(readstate, mask, trsp, &rtrsp[j]);
1257 * Do one read-side critical section, returning false if there was
1258 * no data to read. Can be invoked both from process context and
1259 * from a timer handler.
1261 static bool rcu_torture_one_read(struct torture_random_state *trsp)
1264 unsigned long started;
1265 unsigned long completed;
1267 struct rcu_torture *p;
1270 struct rt_read_seg rtseg[RCUTORTURE_RDR_MAX_SEGS] = { { 0 } };
1271 struct rt_read_seg *rtrsp = &rtseg[0];
1272 struct rt_read_seg *rtrsp1;
1273 unsigned long long ts;
1275 newstate = rcutorture_extend_mask(readstate, trsp);
1276 rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++);
1277 started = cur_ops->get_gp_seq();
1278 ts = rcu_trace_clock_local();
1279 p = rcu_dereference_check(rcu_torture_current,
1280 rcu_read_lock_bh_held() ||
1281 rcu_read_lock_sched_held() ||
1282 srcu_read_lock_held(srcu_ctlp) ||
1285 /* Wait for rcu_torture_writer to get underway */
1286 rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
1289 if (p->rtort_mbtest == 0)
1290 atomic_inc(&n_rcu_torture_mberror);
1291 rtrsp = rcutorture_loop_extend(&readstate, trsp, rtrsp);
1293 pipe_count = p->rtort_pipe_count;
1294 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1295 /* Should not happen, but... */
1296 pipe_count = RCU_TORTURE_PIPE_LEN;
1298 completed = cur_ops->get_gp_seq();
1299 if (pipe_count > 1) {
1300 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
1301 ts, started, completed);
1302 rcu_ftrace_dump(DUMP_ALL);
1304 __this_cpu_inc(rcu_torture_count[pipe_count]);
1305 completed = rcutorture_seq_diff(completed, started);
1306 if (completed > RCU_TORTURE_PIPE_LEN) {
1307 /* Should not happen, but... */
1308 completed = RCU_TORTURE_PIPE_LEN;
1310 __this_cpu_inc(rcu_torture_batch[completed]);
1312 rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
1313 WARN_ON_ONCE(readstate & RCUTORTURE_RDR_MASK);
1315 /* If error or close call, record the sequence of reader protections. */
1316 if ((pipe_count > 1 || completed > 1) && !xchg(&err_segs_recorded, 1)) {
1318 for (rtrsp1 = &rtseg[0]; rtrsp1 < rtrsp; rtrsp1++)
1319 err_segs[i++] = *rtrsp1;
1326 static DEFINE_TORTURE_RANDOM_PERCPU(rcu_torture_timer_rand);
1329 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
1330 * incrementing the corresponding element of the pipeline array. The
1331 * counter in the element should never be greater than 1, otherwise, the
1332 * RCU implementation is broken.
1334 static void rcu_torture_timer(struct timer_list *unused)
1336 atomic_long_inc(&n_rcu_torture_timers);
1337 (void)rcu_torture_one_read(this_cpu_ptr(&rcu_torture_timer_rand));
1339 /* Test call_rcu() invocation from interrupt handler. */
1340 if (cur_ops->call) {
1341 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT);
1344 cur_ops->call(rhp, rcu_torture_timer_cb);
1349 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
1350 * incrementing the corresponding element of the pipeline array. The
1351 * counter in the element should never be greater than 1, otherwise, the
1352 * RCU implementation is broken.
1355 rcu_torture_reader(void *arg)
1357 unsigned long lastsleep = jiffies;
1358 long myid = (long)arg;
1359 int mynumonline = myid;
1360 DEFINE_TORTURE_RANDOM(rand);
1361 struct timer_list t;
1363 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
1364 set_user_nice(current, MAX_NICE);
1365 if (irqreader && cur_ops->irq_capable)
1366 timer_setup_on_stack(&t, rcu_torture_timer, 0);
1367 tick_dep_set_task(current, TICK_DEP_BIT_RCU);
1369 if (irqreader && cur_ops->irq_capable) {
1370 if (!timer_pending(&t))
1371 mod_timer(&t, jiffies + 1);
1373 if (!rcu_torture_one_read(&rand) && !torture_must_stop())
1374 schedule_timeout_interruptible(HZ);
1375 if (time_after(jiffies, lastsleep) && !torture_must_stop()) {
1376 schedule_timeout_interruptible(1);
1377 lastsleep = jiffies + 10;
1379 while (num_online_cpus() < mynumonline && !torture_must_stop())
1380 schedule_timeout_interruptible(HZ / 5);
1381 stutter_wait("rcu_torture_reader");
1382 } while (!torture_must_stop());
1383 if (irqreader && cur_ops->irq_capable) {
1385 destroy_timer_on_stack(&t);
1387 tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
1388 torture_kthread_stopping("rcu_torture_reader");
1393 * Print torture statistics. Caller must ensure that there is only
1394 * one call to this function at a given time!!! This is normally
1395 * accomplished by relying on the module system to only have one copy
1396 * of the module loaded, and then by giving the rcu_torture_stats
1397 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1398 * thread is not running).
1401 rcu_torture_stats_print(void)
1405 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1406 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1407 static unsigned long rtcv_snap = ULONG_MAX;
1408 static bool splatted;
1409 struct task_struct *wtp;
1411 for_each_possible_cpu(cpu) {
1412 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1413 pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
1414 batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
1417 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
1418 if (pipesummary[i] != 0)
1422 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1423 pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
1424 rcu_torture_current,
1425 rcu_torture_current ? "ver" : "VER",
1426 rcu_torture_current_version,
1427 list_empty(&rcu_torture_freelist),
1428 atomic_read(&n_rcu_torture_alloc),
1429 atomic_read(&n_rcu_torture_alloc_fail),
1430 atomic_read(&n_rcu_torture_free));
1431 pr_cont("rtmbe: %d rtbe: %ld rtbke: %ld rtbre: %ld ",
1432 atomic_read(&n_rcu_torture_mberror),
1433 n_rcu_torture_barrier_error,
1434 n_rcu_torture_boost_ktrerror,
1435 n_rcu_torture_boost_rterror);
1436 pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
1437 n_rcu_torture_boost_failure,
1438 n_rcu_torture_boosts,
1439 atomic_long_read(&n_rcu_torture_timers));
1440 torture_onoff_stats();
1441 pr_cont("barrier: %ld/%ld:%ld\n",
1442 n_barrier_successes,
1444 n_rcu_torture_barrier_error);
1446 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1447 if (atomic_read(&n_rcu_torture_mberror) ||
1448 n_rcu_torture_barrier_error || n_rcu_torture_boost_ktrerror ||
1449 n_rcu_torture_boost_rterror || n_rcu_torture_boost_failure ||
1451 pr_cont("%s", "!!! ");
1452 atomic_inc(&n_rcu_torture_error);
1453 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mberror));
1454 WARN_ON_ONCE(n_rcu_torture_barrier_error); // rcu_barrier()
1455 WARN_ON_ONCE(n_rcu_torture_boost_ktrerror); // no boost kthread
1456 WARN_ON_ONCE(n_rcu_torture_boost_rterror); // can't set RT prio
1457 WARN_ON_ONCE(n_rcu_torture_boost_failure); // RCU boost failed
1458 WARN_ON_ONCE(i > 1); // Too-short grace period
1460 pr_cont("Reader Pipe: ");
1461 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1462 pr_cont(" %ld", pipesummary[i]);
1465 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1466 pr_cont("Reader Batch: ");
1467 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1468 pr_cont(" %ld", batchsummary[i]);
1471 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1472 pr_cont("Free-Block Circulation: ");
1473 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1474 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
1480 if (rtcv_snap == rcu_torture_current_version &&
1481 rcu_torture_current != NULL) {
1482 int __maybe_unused flags = 0;
1483 unsigned long __maybe_unused gp_seq = 0;
1485 rcutorture_get_gp_data(cur_ops->ttype,
1487 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp,
1489 wtp = READ_ONCE(writer_task);
1490 pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#lx cpu %d\n",
1491 rcu_torture_writer_state_getname(),
1492 rcu_torture_writer_state, gp_seq, flags,
1493 wtp == NULL ? ~0UL : wtp->state,
1494 wtp == NULL ? -1 : (int)task_cpu(wtp));
1495 if (!splatted && wtp) {
1496 sched_show_task(wtp);
1499 show_rcu_gp_kthreads();
1500 rcu_ftrace_dump(DUMP_ALL);
1502 rtcv_snap = rcu_torture_current_version;
1506 * Periodically prints torture statistics, if periodic statistics printing
1507 * was specified via the stat_interval module parameter.
1510 rcu_torture_stats(void *arg)
1512 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1514 schedule_timeout_interruptible(stat_interval * HZ);
1515 rcu_torture_stats_print();
1516 torture_shutdown_absorb("rcu_torture_stats");
1517 } while (!torture_must_stop());
1518 torture_kthread_stopping("rcu_torture_stats");
1523 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1525 pr_alert("%s" TORTURE_FLAG
1526 "--- %s: nreaders=%d nfakewriters=%d "
1527 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1528 "shuffle_interval=%d stutter=%d irqreader=%d "
1529 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1530 "test_boost=%d/%d test_boost_interval=%d "
1531 "test_boost_duration=%d shutdown_secs=%d "
1532 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d "
1534 "onoff_interval=%d onoff_holdoff=%d\n",
1535 torture_type, tag, nrealreaders, nfakewriters,
1536 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1537 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1538 test_boost, cur_ops->can_boost,
1539 test_boost_interval, test_boost_duration, shutdown_secs,
1540 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff,
1542 onoff_interval, onoff_holdoff);
1545 static int rcutorture_booster_cleanup(unsigned int cpu)
1547 struct task_struct *t;
1549 if (boost_tasks[cpu] == NULL)
1551 mutex_lock(&boost_mutex);
1552 t = boost_tasks[cpu];
1553 boost_tasks[cpu] = NULL;
1554 rcu_torture_enable_rt_throttle();
1555 mutex_unlock(&boost_mutex);
1557 /* This must be outside of the mutex, otherwise deadlock! */
1558 torture_stop_kthread(rcu_torture_boost, t);
1562 static int rcutorture_booster_init(unsigned int cpu)
1566 if (boost_tasks[cpu] != NULL)
1567 return 0; /* Already created, nothing more to do. */
1569 /* Don't allow time recalculation while creating a new task. */
1570 mutex_lock(&boost_mutex);
1571 rcu_torture_disable_rt_throttle();
1572 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
1573 boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
1575 "rcu_torture_boost");
1576 if (IS_ERR(boost_tasks[cpu])) {
1577 retval = PTR_ERR(boost_tasks[cpu]);
1578 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
1579 n_rcu_torture_boost_ktrerror++;
1580 boost_tasks[cpu] = NULL;
1581 mutex_unlock(&boost_mutex);
1584 kthread_bind(boost_tasks[cpu], cpu);
1585 wake_up_process(boost_tasks[cpu]);
1586 mutex_unlock(&boost_mutex);
1591 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
1592 * induces a CPU stall for the time specified by stall_cpu.
1594 static int rcu_torture_stall(void *args)
1596 unsigned long stop_at;
1598 VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
1599 if (stall_cpu_holdoff > 0) {
1600 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
1601 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
1602 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
1604 if (!kthread_should_stop()) {
1605 stop_at = ktime_get_seconds() + stall_cpu;
1606 /* RCU CPU stall is expected behavior in following code. */
1608 if (stall_cpu_irqsoff)
1609 local_irq_disable();
1612 pr_alert("rcu_torture_stall start on CPU %d.\n",
1613 smp_processor_id());
1614 while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(),
1616 continue; /* Induce RCU CPU stall warning. */
1617 if (stall_cpu_irqsoff)
1622 pr_alert("rcu_torture_stall end.\n");
1624 torture_shutdown_absorb("rcu_torture_stall");
1625 while (!kthread_should_stop())
1626 schedule_timeout_interruptible(10 * HZ);
1630 /* Spawn CPU-stall kthread, if stall_cpu specified. */
1631 static int __init rcu_torture_stall_init(void)
1635 return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
1638 /* State structure for forward-progress self-propagating RCU callback. */
1639 struct fwd_cb_state {
1645 * Forward-progress self-propagating RCU callback function. Because
1646 * callbacks run from softirq, this function is an implicit RCU read-side
1649 static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp)
1651 struct fwd_cb_state *fcsp = container_of(rhp, struct fwd_cb_state, rh);
1653 if (READ_ONCE(fcsp->stop)) {
1654 WRITE_ONCE(fcsp->stop, 2);
1657 cur_ops->call(&fcsp->rh, rcu_torture_fwd_prog_cb);
1660 /* State for continuous-flood RCU callbacks. */
1663 struct rcu_fwd_cb *rfc_next;
1664 struct rcu_fwd *rfc_rfp;
1668 #define MAX_FWD_CB_JIFFIES (8 * HZ) /* Maximum CB test duration. */
1669 #define MIN_FWD_CB_LAUNDERS 3 /* This many CB invocations to count. */
1670 #define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */
1671 #define FWD_CBS_HIST_DIV 10 /* Histogram buckets/second. */
1672 #define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV))
1674 struct rcu_launder_hist {
1676 unsigned long launder_gp_seq;
1680 spinlock_t rcu_fwd_lock;
1681 struct rcu_fwd_cb *rcu_fwd_cb_head;
1682 struct rcu_fwd_cb **rcu_fwd_cb_tail;
1684 unsigned long rcu_fwd_startat;
1685 struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST];
1686 unsigned long rcu_launder_gp_seq_start;
1689 struct rcu_fwd *rcu_fwds;
1690 bool rcu_fwd_emergency_stop;
1692 static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp)
1695 unsigned long gps_old;
1699 for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--)
1700 if (rfp->n_launders_hist[i].n_launders > 0)
1702 pr_alert("%s: Callback-invocation histogram (duration %lu jiffies):",
1703 __func__, jiffies - rfp->rcu_fwd_startat);
1704 gps_old = rfp->rcu_launder_gp_seq_start;
1705 for (j = 0; j <= i; j++) {
1706 gps = rfp->n_launders_hist[j].launder_gp_seq;
1707 pr_cont(" %ds/%d: %ld:%ld",
1708 j + 1, FWD_CBS_HIST_DIV,
1709 rfp->n_launders_hist[j].n_launders,
1710 rcutorture_seq_diff(gps, gps_old));
1716 /* Callback function for continuous-flood RCU callbacks. */
1717 static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp)
1719 unsigned long flags;
1721 struct rcu_fwd_cb *rfcp = container_of(rhp, struct rcu_fwd_cb, rh);
1722 struct rcu_fwd_cb **rfcpp;
1723 struct rcu_fwd *rfp = rfcp->rfc_rfp;
1725 rfcp->rfc_next = NULL;
1727 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
1728 rfcpp = rfp->rcu_fwd_cb_tail;
1729 rfp->rcu_fwd_cb_tail = &rfcp->rfc_next;
1730 WRITE_ONCE(*rfcpp, rfcp);
1731 WRITE_ONCE(rfp->n_launders_cb, rfp->n_launders_cb + 1);
1732 i = ((jiffies - rfp->rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV));
1733 if (i >= ARRAY_SIZE(rfp->n_launders_hist))
1734 i = ARRAY_SIZE(rfp->n_launders_hist) - 1;
1735 rfp->n_launders_hist[i].n_launders++;
1736 rfp->n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq();
1737 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
1740 // Give the scheduler a chance, even on nohz_full CPUs.
1741 static void rcu_torture_fwd_prog_cond_resched(unsigned long iter)
1743 if (IS_ENABLED(CONFIG_PREEMPTION) && IS_ENABLED(CONFIG_NO_HZ_FULL)) {
1744 // Real call_rcu() floods hit userspace, so emulate that.
1745 if (need_resched() || (iter & 0xfff))
1749 // No userspace emulation: CB invocation throttles call_rcu()
1754 * Free all callbacks on the rcu_fwd_cb_head list, either because the
1755 * test is over or because we hit an OOM event.
1757 static unsigned long rcu_torture_fwd_prog_cbfree(struct rcu_fwd *rfp)
1759 unsigned long flags;
1760 unsigned long freed = 0;
1761 struct rcu_fwd_cb *rfcp;
1764 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
1765 rfcp = rfp->rcu_fwd_cb_head;
1767 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
1770 rfp->rcu_fwd_cb_head = rfcp->rfc_next;
1771 if (!rfp->rcu_fwd_cb_head)
1772 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head;
1773 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
1776 rcu_torture_fwd_prog_cond_resched(freed);
1777 if (tick_nohz_full_enabled()) {
1778 local_irq_save(flags);
1779 rcu_momentary_dyntick_idle();
1780 local_irq_restore(flags);
1786 /* Carry out need_resched()/cond_resched() forward-progress testing. */
1787 static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp,
1788 int *tested, int *tested_tries)
1792 struct fwd_cb_state fcs;
1797 bool selfpropcb = false;
1798 unsigned long stopat;
1799 static DEFINE_TORTURE_RANDOM(trs);
1801 if (cur_ops->call && cur_ops->sync && cur_ops->cb_barrier) {
1802 init_rcu_head_on_stack(&fcs.rh);
1806 /* Tight loop containing cond_resched(). */
1807 WRITE_ONCE(rcu_fwd_cb_nodelay, true);
1808 cur_ops->sync(); /* Later readers see above write. */
1810 WRITE_ONCE(fcs.stop, 0);
1811 cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb);
1813 cver = READ_ONCE(rcu_torture_current_version);
1814 gps = cur_ops->get_gp_seq();
1815 sd = cur_ops->stall_dur() + 1;
1816 sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div;
1817 dur = sd4 + torture_random(&trs) % (sd - sd4);
1818 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
1819 stopat = rfp->rcu_fwd_startat + dur;
1820 while (time_before(jiffies, stopat) &&
1821 !shutdown_time_arrived() &&
1822 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
1823 idx = cur_ops->readlock();
1825 cur_ops->readunlock(idx);
1826 if (!fwd_progress_need_resched || need_resched())
1830 if (!time_before(jiffies, stopat) &&
1831 !shutdown_time_arrived() &&
1832 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
1834 cver = READ_ONCE(rcu_torture_current_version) - cver;
1835 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
1836 WARN_ON(!cver && gps < 2);
1837 pr_alert("%s: Duration %ld cver %ld gps %ld\n", __func__, dur, cver, gps);
1840 WRITE_ONCE(fcs.stop, 1);
1841 cur_ops->sync(); /* Wait for running CB to complete. */
1842 cur_ops->cb_barrier(); /* Wait for queued callbacks. */
1846 WARN_ON(READ_ONCE(fcs.stop) != 2);
1847 destroy_rcu_head_on_stack(&fcs.rh);
1849 schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */
1850 WRITE_ONCE(rcu_fwd_cb_nodelay, false);
1853 /* Carry out call_rcu() forward-progress testing. */
1854 static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp)
1857 unsigned long flags;
1861 long n_launders_cb_snap;
1865 struct rcu_fwd_cb *rfcp;
1866 struct rcu_fwd_cb *rfcpn;
1867 unsigned long stopat;
1868 unsigned long stoppedat;
1870 if (READ_ONCE(rcu_fwd_emergency_stop))
1871 return; /* Get out of the way quickly, no GP wait! */
1873 return; /* Can't do call_rcu() fwd prog without ->call. */
1875 /* Loop continuously posting RCU callbacks. */
1876 WRITE_ONCE(rcu_fwd_cb_nodelay, true);
1877 cur_ops->sync(); /* Later readers see above write. */
1878 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
1879 stopat = rfp->rcu_fwd_startat + MAX_FWD_CB_JIFFIES;
1881 rfp->n_launders_cb = 0; // Hoist initialization for multi-kthread
1885 for (i = 0; i < ARRAY_SIZE(rfp->n_launders_hist); i++)
1886 rfp->n_launders_hist[i].n_launders = 0;
1887 cver = READ_ONCE(rcu_torture_current_version);
1888 gps = cur_ops->get_gp_seq();
1889 rfp->rcu_launder_gp_seq_start = gps;
1890 tick_dep_set_task(current, TICK_DEP_BIT_RCU);
1891 while (time_before(jiffies, stopat) &&
1892 !shutdown_time_arrived() &&
1893 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
1894 rfcp = READ_ONCE(rfp->rcu_fwd_cb_head);
1897 rfcpn = READ_ONCE(rfcp->rfc_next);
1899 if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS &&
1900 ++n_max_gps >= MIN_FWD_CBS_LAUNDERED)
1902 rfp->rcu_fwd_cb_head = rfcpn;
1906 rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL);
1907 if (WARN_ON_ONCE(!rfcp)) {
1908 schedule_timeout_interruptible(1);
1914 rfcp->rfc_rfp = rfp;
1916 cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr);
1917 rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs);
1918 if (tick_nohz_full_enabled()) {
1919 local_irq_save(flags);
1920 rcu_momentary_dyntick_idle();
1921 local_irq_restore(flags);
1924 stoppedat = jiffies;
1925 n_launders_cb_snap = READ_ONCE(rfp->n_launders_cb);
1926 cver = READ_ONCE(rcu_torture_current_version) - cver;
1927 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
1928 cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */
1929 (void)rcu_torture_fwd_prog_cbfree(rfp);
1931 if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) &&
1932 !shutdown_time_arrived()) {
1933 WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED);
1934 pr_alert("%s Duration %lu barrier: %lu pending %ld n_launders: %ld n_launders_sa: %ld n_max_gps: %ld n_max_cbs: %ld cver %ld gps %ld\n",
1936 stoppedat - rfp->rcu_fwd_startat, jiffies - stoppedat,
1937 n_launders + n_max_cbs - n_launders_cb_snap,
1938 n_launders, n_launders_sa,
1939 n_max_gps, n_max_cbs, cver, gps);
1940 rcu_torture_fwd_cb_hist(rfp);
1942 schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */
1943 tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
1944 WRITE_ONCE(rcu_fwd_cb_nodelay, false);
1949 * OOM notifier, but this only prints diagnostic information for the
1950 * current forward-progress test.
1952 static int rcutorture_oom_notify(struct notifier_block *self,
1953 unsigned long notused, void *nfreed)
1955 struct rcu_fwd *rfp = rcu_fwds;
1957 WARN(1, "%s invoked upon OOM during forward-progress testing.\n",
1959 rcu_torture_fwd_cb_hist(rfp);
1960 rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp->rcu_fwd_startat)) / 2);
1961 WRITE_ONCE(rcu_fwd_emergency_stop, true);
1962 smp_mb(); /* Emergency stop before free and wait to avoid hangs. */
1963 pr_info("%s: Freed %lu RCU callbacks.\n",
1964 __func__, rcu_torture_fwd_prog_cbfree(rfp));
1966 pr_info("%s: Freed %lu RCU callbacks.\n",
1967 __func__, rcu_torture_fwd_prog_cbfree(rfp));
1969 pr_info("%s: Freed %lu RCU callbacks.\n",
1970 __func__, rcu_torture_fwd_prog_cbfree(rfp));
1971 smp_mb(); /* Frees before return to avoid redoing OOM. */
1972 (*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */
1973 pr_info("%s returning after OOM processing.\n", __func__);
1977 static struct notifier_block rcutorture_oom_nb = {
1978 .notifier_call = rcutorture_oom_notify
1981 /* Carry out grace-period forward-progress testing. */
1982 static int rcu_torture_fwd_prog(void *args)
1984 struct rcu_fwd *rfp = args;
1986 int tested_tries = 0;
1988 VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started");
1989 rcu_bind_current_to_nocb();
1990 if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST))
1991 set_user_nice(current, MAX_NICE);
1993 schedule_timeout_interruptible(fwd_progress_holdoff * HZ);
1994 WRITE_ONCE(rcu_fwd_emergency_stop, false);
1995 register_oom_notifier(&rcutorture_oom_nb);
1996 rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries);
1997 rcu_torture_fwd_prog_cr(rfp);
1998 unregister_oom_notifier(&rcutorture_oom_nb);
2000 /* Avoid slow periods, better to test when busy. */
2001 stutter_wait("rcu_torture_fwd_prog");
2002 } while (!torture_must_stop());
2003 /* Short runs might not contain a valid forward-progress attempt. */
2004 WARN_ON(!tested && tested_tries >= 5);
2005 pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries);
2006 torture_kthread_stopping("rcu_torture_fwd_prog");
2010 /* If forward-progress checking is requested and feasible, spawn the thread. */
2011 static int __init rcu_torture_fwd_prog_init(void)
2013 struct rcu_fwd *rfp;
2016 return 0; /* Not requested, so don't do it. */
2017 if (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0 ||
2018 cur_ops == &rcu_busted_ops) {
2019 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test");
2022 if (stall_cpu > 0) {
2023 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing");
2024 if (IS_MODULE(CONFIG_RCU_TORTURE_TESTS))
2025 return -EINVAL; /* In module, can fail back to user. */
2026 WARN_ON(1); /* Make sure rcutorture notices conflict. */
2029 if (fwd_progress_holdoff <= 0)
2030 fwd_progress_holdoff = 1;
2031 if (fwd_progress_div <= 0)
2032 fwd_progress_div = 4;
2033 rfp = kzalloc(sizeof(*rfp), GFP_KERNEL);
2036 spin_lock_init(&rfp->rcu_fwd_lock);
2037 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head;
2038 return torture_create_kthread(rcu_torture_fwd_prog, rfp, fwd_prog_task);
2041 /* Callback function for RCU barrier testing. */
2042 static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
2044 atomic_inc(&barrier_cbs_invoked);
2047 /* kthread function to register callbacks used to test RCU barriers. */
2048 static int rcu_torture_barrier_cbs(void *arg)
2050 long myid = (long)arg;
2053 struct rcu_head rcu;
2055 init_rcu_head_on_stack(&rcu);
2056 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
2057 set_user_nice(current, MAX_NICE);
2059 wait_event(barrier_cbs_wq[myid],
2061 smp_load_acquire(&barrier_phase)) != lastphase ||
2062 torture_must_stop());
2063 lastphase = newphase;
2064 if (torture_must_stop())
2067 * The above smp_load_acquire() ensures barrier_phase load
2068 * is ordered before the following ->call().
2070 local_irq_disable(); /* Just to test no-irq call_rcu(). */
2071 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
2073 if (atomic_dec_and_test(&barrier_cbs_count))
2074 wake_up(&barrier_wq);
2075 } while (!torture_must_stop());
2076 if (cur_ops->cb_barrier != NULL)
2077 cur_ops->cb_barrier();
2078 destroy_rcu_head_on_stack(&rcu);
2079 torture_kthread_stopping("rcu_torture_barrier_cbs");
2083 /* kthread function to drive and coordinate RCU barrier testing. */
2084 static int rcu_torture_barrier(void *arg)
2088 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
2090 atomic_set(&barrier_cbs_invoked, 0);
2091 atomic_set(&barrier_cbs_count, n_barrier_cbs);
2092 /* Ensure barrier_phase ordered after prior assignments. */
2093 smp_store_release(&barrier_phase, !barrier_phase);
2094 for (i = 0; i < n_barrier_cbs; i++)
2095 wake_up(&barrier_cbs_wq[i]);
2096 wait_event(barrier_wq,
2097 atomic_read(&barrier_cbs_count) == 0 ||
2098 torture_must_stop());
2099 if (torture_must_stop())
2101 n_barrier_attempts++;
2102 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
2103 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
2104 n_rcu_torture_barrier_error++;
2105 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
2106 atomic_read(&barrier_cbs_invoked),
2110 n_barrier_successes++;
2112 schedule_timeout_interruptible(HZ / 10);
2113 } while (!torture_must_stop());
2114 torture_kthread_stopping("rcu_torture_barrier");
2118 /* Initialize RCU barrier testing. */
2119 static int rcu_torture_barrier_init(void)
2124 if (n_barrier_cbs <= 0)
2126 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
2127 pr_alert("%s" TORTURE_FLAG
2128 " Call or barrier ops missing for %s,\n",
2129 torture_type, cur_ops->name);
2130 pr_alert("%s" TORTURE_FLAG
2131 " RCU barrier testing omitted from run.\n",
2135 atomic_set(&barrier_cbs_count, 0);
2136 atomic_set(&barrier_cbs_invoked, 0);
2138 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]),
2141 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL);
2142 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
2144 for (i = 0; i < n_barrier_cbs; i++) {
2145 init_waitqueue_head(&barrier_cbs_wq[i]);
2146 ret = torture_create_kthread(rcu_torture_barrier_cbs,
2148 barrier_cbs_tasks[i]);
2152 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
2155 /* Clean up after RCU barrier testing. */
2156 static void rcu_torture_barrier_cleanup(void)
2160 torture_stop_kthread(rcu_torture_barrier, barrier_task);
2161 if (barrier_cbs_tasks != NULL) {
2162 for (i = 0; i < n_barrier_cbs; i++)
2163 torture_stop_kthread(rcu_torture_barrier_cbs,
2164 barrier_cbs_tasks[i]);
2165 kfree(barrier_cbs_tasks);
2166 barrier_cbs_tasks = NULL;
2168 if (barrier_cbs_wq != NULL) {
2169 kfree(barrier_cbs_wq);
2170 barrier_cbs_wq = NULL;
2174 static bool rcu_torture_can_boost(void)
2176 static int boost_warn_once;
2179 if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2)
2182 prio = rcu_get_gp_kthreads_prio();
2187 if (boost_warn_once == 1)
2190 pr_alert("%s: WARN: RCU kthread priority too low to test boosting. Skipping RCU boost test. Try passing rcutree.kthread_prio > 1 on the kernel command line.\n", KBUILD_MODNAME);
2191 boost_warn_once = 1;
2198 static enum cpuhp_state rcutor_hp;
2201 rcu_torture_cleanup(void)
2205 unsigned long gp_seq = 0;
2208 if (torture_cleanup_begin()) {
2209 if (cur_ops->cb_barrier != NULL)
2210 cur_ops->cb_barrier();
2214 torture_cleanup_end();
2218 show_rcu_gp_kthreads();
2219 rcu_torture_barrier_cleanup();
2220 torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_task);
2221 torture_stop_kthread(rcu_torture_stall, stall_task);
2222 torture_stop_kthread(rcu_torture_writer, writer_task);
2225 for (i = 0; i < nrealreaders; i++)
2226 torture_stop_kthread(rcu_torture_reader,
2228 kfree(reader_tasks);
2230 rcu_torture_current = NULL;
2232 if (fakewriter_tasks) {
2233 for (i = 0; i < nfakewriters; i++) {
2234 torture_stop_kthread(rcu_torture_fakewriter,
2235 fakewriter_tasks[i]);
2237 kfree(fakewriter_tasks);
2238 fakewriter_tasks = NULL;
2241 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq);
2242 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq);
2243 pr_alert("%s: End-test grace-period state: g%lu f%#x\n",
2244 cur_ops->name, gp_seq, flags);
2245 torture_stop_kthread(rcu_torture_stats, stats_task);
2246 torture_stop_kthread(rcu_torture_fqs, fqs_task);
2247 if (rcu_torture_can_boost())
2248 cpuhp_remove_state(rcutor_hp);
2251 * Wait for all RCU callbacks to fire, then do torture-type-specific
2252 * cleanup operations.
2254 if (cur_ops->cb_barrier != NULL)
2255 cur_ops->cb_barrier();
2256 if (cur_ops->cleanup != NULL)
2259 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
2261 if (err_segs_recorded) {
2262 pr_alert("Failure/close-call rcutorture reader segments:\n");
2263 if (rt_read_nsegs == 0)
2264 pr_alert("\t: No segments recorded!!!\n");
2266 for (i = 0; i < rt_read_nsegs; i++) {
2267 pr_alert("\t%d: %#x ", i, err_segs[i].rt_readstate);
2268 if (err_segs[i].rt_delay_jiffies != 0) {
2269 pr_cont("%s%ldjiffies", firsttime ? "" : "+",
2270 err_segs[i].rt_delay_jiffies);
2273 if (err_segs[i].rt_delay_ms != 0) {
2274 pr_cont("%s%ldms", firsttime ? "" : "+",
2275 err_segs[i].rt_delay_ms);
2278 if (err_segs[i].rt_delay_us != 0) {
2279 pr_cont("%s%ldus", firsttime ? "" : "+",
2280 err_segs[i].rt_delay_us);
2284 err_segs[i].rt_preempted ? "preempted" : "");
2288 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
2289 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
2290 else if (torture_onoff_failures())
2291 rcu_torture_print_module_parms(cur_ops,
2292 "End of test: RCU_HOTPLUG");
2294 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
2295 torture_cleanup_end();
2298 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
2299 static void rcu_torture_leak_cb(struct rcu_head *rhp)
2303 static void rcu_torture_err_cb(struct rcu_head *rhp)
2306 * This -might- happen due to race conditions, but is unlikely.
2307 * The scenario that leads to this happening is that the
2308 * first of the pair of duplicate callbacks is queued,
2309 * someone else starts a grace period that includes that
2310 * callback, then the second of the pair must wait for the
2311 * next grace period. Unlikely, but can happen. If it
2312 * does happen, the debug-objects subsystem won't have splatted.
2314 pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME);
2316 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
2319 * Verify that double-free causes debug-objects to complain, but only
2320 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
2321 * cannot be carried out.
2323 static void rcu_test_debug_objects(void)
2325 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
2326 struct rcu_head rh1;
2327 struct rcu_head rh2;
2329 init_rcu_head_on_stack(&rh1);
2330 init_rcu_head_on_stack(&rh2);
2331 pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME);
2333 /* Try to queue the rh2 pair of callbacks for the same grace period. */
2334 preempt_disable(); /* Prevent preemption from interrupting test. */
2335 rcu_read_lock(); /* Make it impossible to finish a grace period. */
2336 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
2337 local_irq_disable(); /* Make it harder to start a new grace period. */
2338 call_rcu(&rh2, rcu_torture_leak_cb);
2339 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
2344 /* Wait for them all to get done so we can safely return. */
2346 pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME);
2347 destroy_rcu_head_on_stack(&rh1);
2348 destroy_rcu_head_on_stack(&rh2);
2349 #else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
2350 pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME);
2351 #endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
2354 static void rcutorture_sync(void)
2356 static unsigned long n;
2358 if (cur_ops->sync && !(++n & 0xfff))
2363 rcu_torture_init(void)
2368 static struct rcu_torture_ops *torture_ops[] = {
2369 &rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops,
2370 &busted_srcud_ops, &tasks_ops, &trivial_ops,
2373 if (!torture_init_begin(torture_type, verbose))
2376 /* Process args and tell the world that the torturer is on the job. */
2377 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
2378 cur_ops = torture_ops[i];
2379 if (strcmp(torture_type, cur_ops->name) == 0)
2382 if (i == ARRAY_SIZE(torture_ops)) {
2383 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
2385 pr_alert("rcu-torture types:");
2386 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
2387 pr_cont(" %s", torture_ops[i]->name);
2389 WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST));
2394 if (cur_ops->fqs == NULL && fqs_duration != 0) {
2395 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
2401 if (nreaders >= 0) {
2402 nrealreaders = nreaders;
2404 nrealreaders = num_online_cpus() - 2 - nreaders;
2405 if (nrealreaders <= 0)
2408 rcu_torture_print_module_parms(cur_ops, "Start of test");
2410 /* Set up the freelist. */
2412 INIT_LIST_HEAD(&rcu_torture_freelist);
2413 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
2414 rcu_tortures[i].rtort_mbtest = 0;
2415 list_add_tail(&rcu_tortures[i].rtort_free,
2416 &rcu_torture_freelist);
2419 /* Initialize the statistics so that each run gets its own numbers. */
2421 rcu_torture_current = NULL;
2422 rcu_torture_current_version = 0;
2423 atomic_set(&n_rcu_torture_alloc, 0);
2424 atomic_set(&n_rcu_torture_alloc_fail, 0);
2425 atomic_set(&n_rcu_torture_free, 0);
2426 atomic_set(&n_rcu_torture_mberror, 0);
2427 atomic_set(&n_rcu_torture_error, 0);
2428 n_rcu_torture_barrier_error = 0;
2429 n_rcu_torture_boost_ktrerror = 0;
2430 n_rcu_torture_boost_rterror = 0;
2431 n_rcu_torture_boost_failure = 0;
2432 n_rcu_torture_boosts = 0;
2433 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
2434 atomic_set(&rcu_torture_wcount[i], 0);
2435 for_each_possible_cpu(cpu) {
2436 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
2437 per_cpu(rcu_torture_count, cpu)[i] = 0;
2438 per_cpu(rcu_torture_batch, cpu)[i] = 0;
2441 err_segs_recorded = 0;
2444 /* Start up the kthreads. */
2446 firsterr = torture_create_kthread(rcu_torture_writer, NULL,
2450 if (nfakewriters > 0) {
2451 fakewriter_tasks = kcalloc(nfakewriters,
2452 sizeof(fakewriter_tasks[0]),
2454 if (fakewriter_tasks == NULL) {
2455 VERBOSE_TOROUT_ERRSTRING("out of memory");
2460 for (i = 0; i < nfakewriters; i++) {
2461 firsterr = torture_create_kthread(rcu_torture_fakewriter,
2462 NULL, fakewriter_tasks[i]);
2466 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
2468 if (reader_tasks == NULL) {
2469 VERBOSE_TOROUT_ERRSTRING("out of memory");
2473 for (i = 0; i < nrealreaders; i++) {
2474 firsterr = torture_create_kthread(rcu_torture_reader, (void *)i,
2479 if (stat_interval > 0) {
2480 firsterr = torture_create_kthread(rcu_torture_stats, NULL,
2485 if (test_no_idle_hz && shuffle_interval > 0) {
2486 firsterr = torture_shuffle_init(shuffle_interval * HZ);
2495 t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ;
2496 firsterr = torture_stutter_init(stutter * HZ, t);
2500 if (fqs_duration < 0)
2503 /* Create the fqs thread */
2504 firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
2509 if (test_boost_interval < 1)
2510 test_boost_interval = 1;
2511 if (test_boost_duration < 2)
2512 test_boost_duration = 2;
2513 if (rcu_torture_can_boost()) {
2515 boost_starttime = jiffies + test_boost_interval * HZ;
2517 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE",
2518 rcutorture_booster_init,
2519 rcutorture_booster_cleanup);
2522 rcutor_hp = firsterr;
2524 shutdown_jiffies = jiffies + shutdown_secs * HZ;
2525 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
2528 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval,
2532 firsterr = rcu_torture_stall_init();
2535 firsterr = rcu_torture_fwd_prog_init();
2538 firsterr = rcu_torture_barrier_init();
2542 rcu_test_debug_objects();
2548 rcu_torture_cleanup();
2552 module_init(rcu_torture_init);
2553 module_exit(rcu_torture_cleanup);