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.rst
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_wait.h>
24 #include <linux/interrupt.h>
25 #include <linux/sched/signal.h>
26 #include <uapi/linux/sched/types.h>
27 #include <linux/atomic.h>
28 #include <linux/bitops.h>
29 #include <linux/completion.h>
30 #include <linux/moduleparam.h>
31 #include <linux/percpu.h>
32 #include <linux/notifier.h>
33 #include <linux/reboot.h>
34 #include <linux/freezer.h>
35 #include <linux/cpu.h>
36 #include <linux/delay.h>
37 #include <linux/stat.h>
38 #include <linux/srcu.h>
39 #include <linux/slab.h>
40 #include <linux/trace_clock.h>
41 #include <asm/byteorder.h>
42 #include <linux/torture.h>
43 #include <linux/vmalloc.h>
44 #include <linux/sched/debug.h>
45 #include <linux/sched/sysctl.h>
46 #include <linux/oom.h>
47 #include <linux/tick.h>
48 #include <linux/rcupdate_trace.h>
49 #include <linux/nmi.h>
53 MODULE_LICENSE("GPL");
54 MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
56 /* Bits for ->extendables field, extendables param, and related definitions. */
57 #define RCUTORTURE_RDR_SHIFT_1 8 /* Put SRCU index in upper bits. */
58 #define RCUTORTURE_RDR_MASK_1 (1 << RCUTORTURE_RDR_SHIFT_1)
59 #define RCUTORTURE_RDR_SHIFT_2 9 /* Put SRCU index in upper bits. */
60 #define RCUTORTURE_RDR_MASK_2 (1 << RCUTORTURE_RDR_SHIFT_2)
61 #define RCUTORTURE_RDR_BH 0x01 /* Extend readers by disabling bh. */
62 #define RCUTORTURE_RDR_IRQ 0x02 /* ... disabling interrupts. */
63 #define RCUTORTURE_RDR_PREEMPT 0x04 /* ... disabling preemption. */
64 #define RCUTORTURE_RDR_RBH 0x08 /* ... rcu_read_lock_bh(). */
65 #define RCUTORTURE_RDR_SCHED 0x10 /* ... rcu_read_lock_sched(). */
66 #define RCUTORTURE_RDR_RCU_1 0x20 /* ... entering another RCU reader. */
67 #define RCUTORTURE_RDR_RCU_2 0x40 /* ... entering another RCU reader. */
68 #define RCUTORTURE_RDR_NBITS 7 /* Number of bits defined above. */
69 #define RCUTORTURE_MAX_EXTEND \
70 (RCUTORTURE_RDR_BH | RCUTORTURE_RDR_IRQ | RCUTORTURE_RDR_PREEMPT | \
71 RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED)
72 #define RCUTORTURE_RDR_MAX_LOOPS 0x7 /* Maximum reader extensions. */
73 /* Must be power of two minus one. */
74 #define RCUTORTURE_RDR_MAX_SEGS (RCUTORTURE_RDR_MAX_LOOPS + 3)
76 torture_param(int, extendables, RCUTORTURE_MAX_EXTEND,
77 "Extend readers by disabling bh (1), irqs (2), or preempt (4)");
78 torture_param(int, fqs_duration, 0,
79 "Duration of fqs bursts (us), 0 to disable");
80 torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
81 torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
82 torture_param(int, fwd_progress, 1, "Test grace-period forward progress");
83 torture_param(int, fwd_progress_div, 4, "Fraction of CPU stall to wait");
84 torture_param(int, fwd_progress_holdoff, 60,
85 "Time between forward-progress tests (s)");
86 torture_param(bool, fwd_progress_need_resched, 1,
87 "Hide cond_resched() behind need_resched()");
88 torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
89 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
90 torture_param(bool, gp_normal, false,
91 "Use normal (non-expedited) GP wait primitives");
92 torture_param(bool, gp_poll, false, "Use polling GP wait primitives");
93 torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
94 torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
95 torture_param(int, leakpointer, 0, "Leak pointer dereferences from readers");
96 torture_param(int, n_barrier_cbs, 0,
97 "# of callbacks/kthreads for barrier testing");
98 torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
99 torture_param(int, nreaders, -1, "Number of RCU reader threads");
100 torture_param(int, object_debug, 0,
101 "Enable debug-object double call_rcu() testing");
102 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
103 torture_param(int, onoff_interval, 0,
104 "Time between CPU hotplugs (jiffies), 0=disable");
105 torture_param(int, nocbs_nthreads, 0, "Number of NOCB toggle threads, 0 to disable");
106 torture_param(int, nocbs_toggle, 1000, "Time between toggling nocb state (ms)");
107 torture_param(int, read_exit_delay, 13,
108 "Delay between read-then-exit episodes (s)");
109 torture_param(int, read_exit_burst, 16,
110 "# of read-then-exit bursts per episode, zero to disable");
111 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
112 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
113 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
114 torture_param(int, stall_cpu_holdoff, 10,
115 "Time to wait before starting stall (s).");
116 torture_param(bool, stall_no_softlockup, false,
117 "Avoid softlockup warning during cpu stall.");
118 torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling.");
119 torture_param(int, stall_cpu_block, 0, "Sleep while stalling.");
120 torture_param(int, stall_gp_kthread, 0,
121 "Grace-period kthread stall duration (s).");
122 torture_param(int, stat_interval, 60,
123 "Number of seconds between stats printk()s");
124 torture_param(int, stutter, 5, "Number of seconds to run/halt test");
125 torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
126 torture_param(int, test_boost_duration, 4,
127 "Duration of each boost test, seconds.");
128 torture_param(int, test_boost_interval, 7,
129 "Interval between boost tests, seconds.");
130 torture_param(bool, test_no_idle_hz, true,
131 "Test support for tickless idle CPUs");
132 torture_param(int, verbose, 1,
133 "Enable verbose debugging printk()s");
135 static char *torture_type = "rcu";
136 module_param(torture_type, charp, 0444);
137 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, srcu, ...)");
139 static int nrealnocbers;
140 static int nrealreaders;
141 static struct task_struct *writer_task;
142 static struct task_struct **fakewriter_tasks;
143 static struct task_struct **reader_tasks;
144 static struct task_struct **nocb_tasks;
145 static struct task_struct *stats_task;
146 static struct task_struct *fqs_task;
147 static struct task_struct *boost_tasks[NR_CPUS];
148 static struct task_struct *stall_task;
149 static struct task_struct **fwd_prog_tasks;
150 static struct task_struct **barrier_cbs_tasks;
151 static struct task_struct *barrier_task;
152 static struct task_struct *read_exit_task;
154 #define RCU_TORTURE_PIPE_LEN 10
156 // Mailbox-like structure to check RCU global memory ordering.
157 struct rcu_torture_reader_check {
158 unsigned long rtc_myloops;
160 unsigned long rtc_chkloops;
162 struct rcu_torture_reader_check *rtc_assigner;
163 } ____cacheline_internodealigned_in_smp;
165 // Update-side data structure used to check RCU readers.
167 struct rcu_head rtort_rcu;
168 int rtort_pipe_count;
169 struct list_head rtort_free;
171 struct rcu_torture_reader_check *rtort_chkp;
174 static LIST_HEAD(rcu_torture_freelist);
175 static struct rcu_torture __rcu *rcu_torture_current;
176 static unsigned long rcu_torture_current_version;
177 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
178 static DEFINE_SPINLOCK(rcu_torture_lock);
179 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count);
180 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch);
181 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
182 static struct rcu_torture_reader_check *rcu_torture_reader_mbchk;
183 static atomic_t n_rcu_torture_alloc;
184 static atomic_t n_rcu_torture_alloc_fail;
185 static atomic_t n_rcu_torture_free;
186 static atomic_t n_rcu_torture_mberror;
187 static atomic_t n_rcu_torture_mbchk_fail;
188 static atomic_t n_rcu_torture_mbchk_tries;
189 static atomic_t n_rcu_torture_error;
190 static long n_rcu_torture_barrier_error;
191 static long n_rcu_torture_boost_ktrerror;
192 static long n_rcu_torture_boost_rterror;
193 static long n_rcu_torture_boost_failure;
194 static long n_rcu_torture_boosts;
195 static atomic_long_t n_rcu_torture_timers;
196 static long n_barrier_attempts;
197 static long n_barrier_successes; /* did rcu_barrier test succeed? */
198 static unsigned long n_read_exits;
199 static struct list_head rcu_torture_removed;
200 static unsigned long shutdown_jiffies;
201 static unsigned long start_gp_seq;
202 static atomic_long_t n_nocb_offload;
203 static atomic_long_t n_nocb_deoffload;
205 static int rcu_torture_writer_state;
206 #define RTWS_FIXED_DELAY 0
208 #define RTWS_REPLACE 2
209 #define RTWS_DEF_FREE 3
210 #define RTWS_EXP_SYNC 4
211 #define RTWS_COND_GET 5
212 #define RTWS_COND_SYNC 6
213 #define RTWS_POLL_GET 7
214 #define RTWS_POLL_WAIT 8
216 #define RTWS_STUTTER 10
217 #define RTWS_STOPPING 11
218 static const char * const rcu_torture_writer_state_names[] = {
233 /* Record reader segment types and duration for first failing read. */
236 unsigned long rt_delay_jiffies;
237 unsigned long rt_delay_ms;
238 unsigned long rt_delay_us;
241 static int err_segs_recorded;
242 static struct rt_read_seg err_segs[RCUTORTURE_RDR_MAX_SEGS];
243 static int rt_read_nsegs;
245 static const char *rcu_torture_writer_state_getname(void)
247 unsigned int i = READ_ONCE(rcu_torture_writer_state);
249 if (i >= ARRAY_SIZE(rcu_torture_writer_state_names))
251 return rcu_torture_writer_state_names[i];
254 #ifdef CONFIG_RCU_TRACE
255 static u64 notrace rcu_trace_clock_local(void)
257 u64 ts = trace_clock_local();
259 (void)do_div(ts, NSEC_PER_USEC);
262 #else /* #ifdef CONFIG_RCU_TRACE */
263 static u64 notrace rcu_trace_clock_local(void)
267 #endif /* #else #ifdef CONFIG_RCU_TRACE */
270 * Stop aggressive CPU-hog tests a bit before the end of the test in order
271 * to avoid interfering with test shutdown.
273 static bool shutdown_time_arrived(void)
275 return shutdown_secs && time_after(jiffies, shutdown_jiffies - 30 * HZ);
278 static unsigned long boost_starttime; /* jiffies of next boost test start. */
279 static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
280 /* and boost task create/destroy. */
281 static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
282 static bool barrier_phase; /* Test phase. */
283 static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
284 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
285 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
287 static atomic_t rcu_fwd_cb_nodelay; /* Short rcu_torture_delay() delays. */
290 * Allocate an element from the rcu_tortures pool.
292 static struct rcu_torture *
293 rcu_torture_alloc(void)
297 spin_lock_bh(&rcu_torture_lock);
298 if (list_empty(&rcu_torture_freelist)) {
299 atomic_inc(&n_rcu_torture_alloc_fail);
300 spin_unlock_bh(&rcu_torture_lock);
303 atomic_inc(&n_rcu_torture_alloc);
304 p = rcu_torture_freelist.next;
306 spin_unlock_bh(&rcu_torture_lock);
307 return container_of(p, struct rcu_torture, rtort_free);
311 * Free an element to the rcu_tortures pool.
314 rcu_torture_free(struct rcu_torture *p)
316 atomic_inc(&n_rcu_torture_free);
317 spin_lock_bh(&rcu_torture_lock);
318 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
319 spin_unlock_bh(&rcu_torture_lock);
323 * Operations vector for selecting different types of tests.
326 struct rcu_torture_ops {
329 void (*cleanup)(void);
330 int (*readlock)(void);
331 void (*read_delay)(struct torture_random_state *rrsp,
332 struct rt_read_seg *rtrsp);
333 void (*readunlock)(int idx);
334 int (*readlock_held)(void);
335 unsigned long (*get_gp_seq)(void);
336 unsigned long (*gp_diff)(unsigned long new, unsigned long old);
337 void (*deferred_free)(struct rcu_torture *p);
339 void (*exp_sync)(void);
340 unsigned long (*get_gp_state)(void);
341 unsigned long (*start_gp_poll)(void);
342 bool (*poll_gp_state)(unsigned long oldstate);
343 void (*cond_sync)(unsigned long oldstate);
344 call_rcu_func_t call;
345 void (*cb_barrier)(void);
348 void (*gp_kthread_dbg)(void);
349 bool (*check_boost_failed)(unsigned long gp_state, int *cpup);
350 int (*stall_dur)(void);
360 static struct rcu_torture_ops *cur_ops;
363 * Definitions for rcu torture testing.
366 static int torture_readlock_not_held(void)
368 return rcu_read_lock_bh_held() || rcu_read_lock_sched_held();
371 static int rcu_torture_read_lock(void) __acquires(RCU)
378 rcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
380 unsigned long started;
381 unsigned long completed;
382 const unsigned long shortdelay_us = 200;
383 unsigned long longdelay_ms = 300;
384 unsigned long long ts;
386 /* We want a short delay sometimes to make a reader delay the grace
387 * period, and we want a long delay occasionally to trigger
388 * force_quiescent_state. */
390 if (!atomic_read(&rcu_fwd_cb_nodelay) &&
391 !(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) {
392 started = cur_ops->get_gp_seq();
393 ts = rcu_trace_clock_local();
394 if (preempt_count() & (SOFTIRQ_MASK | HARDIRQ_MASK))
395 longdelay_ms = 5; /* Avoid triggering BH limits. */
396 mdelay(longdelay_ms);
397 rtrsp->rt_delay_ms = longdelay_ms;
398 completed = cur_ops->get_gp_seq();
399 do_trace_rcu_torture_read(cur_ops->name, NULL, ts,
402 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) {
403 udelay(shortdelay_us);
404 rtrsp->rt_delay_us = shortdelay_us;
406 if (!preempt_count() &&
407 !(torture_random(rrsp) % (nrealreaders * 500))) {
408 torture_preempt_schedule(); /* QS only if preemptible. */
409 rtrsp->rt_preempted = true;
413 static void rcu_torture_read_unlock(int idx) __releases(RCU)
419 * Update callback in the pipe. This should be invoked after a grace period.
422 rcu_torture_pipe_update_one(struct rcu_torture *rp)
425 struct rcu_torture_reader_check *rtrcp = READ_ONCE(rp->rtort_chkp);
428 WRITE_ONCE(rp->rtort_chkp, NULL);
429 smp_store_release(&rtrcp->rtc_ready, 1); // Pair with smp_load_acquire().
431 i = READ_ONCE(rp->rtort_pipe_count);
432 if (i > RCU_TORTURE_PIPE_LEN)
433 i = RCU_TORTURE_PIPE_LEN;
434 atomic_inc(&rcu_torture_wcount[i]);
435 WRITE_ONCE(rp->rtort_pipe_count, i + 1);
436 if (rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
437 rp->rtort_mbtest = 0;
444 * Update all callbacks in the pipe. Suitable for synchronous grace-period
448 rcu_torture_pipe_update(struct rcu_torture *old_rp)
450 struct rcu_torture *rp;
451 struct rcu_torture *rp1;
454 list_add(&old_rp->rtort_free, &rcu_torture_removed);
455 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
456 if (rcu_torture_pipe_update_one(rp)) {
457 list_del(&rp->rtort_free);
458 rcu_torture_free(rp);
464 rcu_torture_cb(struct rcu_head *p)
466 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
468 if (torture_must_stop_irq()) {
469 /* Test is ending, just drop callbacks on the floor. */
470 /* The next initialization will pick up the pieces. */
473 if (rcu_torture_pipe_update_one(rp))
474 rcu_torture_free(rp);
476 cur_ops->deferred_free(rp);
479 static unsigned long rcu_no_completed(void)
484 static void rcu_torture_deferred_free(struct rcu_torture *p)
486 call_rcu(&p->rtort_rcu, rcu_torture_cb);
489 static void rcu_sync_torture_init(void)
491 INIT_LIST_HEAD(&rcu_torture_removed);
494 static struct rcu_torture_ops rcu_ops = {
496 .init = rcu_sync_torture_init,
497 .readlock = rcu_torture_read_lock,
498 .read_delay = rcu_read_delay,
499 .readunlock = rcu_torture_read_unlock,
500 .readlock_held = torture_readlock_not_held,
501 .get_gp_seq = rcu_get_gp_seq,
502 .gp_diff = rcu_seq_diff,
503 .deferred_free = rcu_torture_deferred_free,
504 .sync = synchronize_rcu,
505 .exp_sync = synchronize_rcu_expedited,
506 .get_gp_state = get_state_synchronize_rcu,
507 .start_gp_poll = start_poll_synchronize_rcu,
508 .poll_gp_state = poll_state_synchronize_rcu,
509 .cond_sync = cond_synchronize_rcu,
511 .cb_barrier = rcu_barrier,
512 .fqs = rcu_force_quiescent_state,
514 .gp_kthread_dbg = show_rcu_gp_kthreads,
515 .check_boost_failed = rcu_check_boost_fail,
516 .stall_dur = rcu_jiffies_till_stall_check,
518 .can_boost = IS_ENABLED(CONFIG_RCU_BOOST),
519 .extendables = RCUTORTURE_MAX_EXTEND,
524 * Don't even think about trying any of these in real life!!!
525 * The names includes "busted", and they really means it!
526 * The only purpose of these functions is to provide a buggy RCU
527 * implementation to make sure that rcutorture correctly emits
528 * buggy-RCU error messages.
530 static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
532 /* This is a deliberate bug for testing purposes only! */
533 rcu_torture_cb(&p->rtort_rcu);
536 static void synchronize_rcu_busted(void)
538 /* This is a deliberate bug for testing purposes only! */
542 call_rcu_busted(struct rcu_head *head, rcu_callback_t func)
544 /* This is a deliberate bug for testing purposes only! */
548 static struct rcu_torture_ops rcu_busted_ops = {
549 .ttype = INVALID_RCU_FLAVOR,
550 .init = rcu_sync_torture_init,
551 .readlock = rcu_torture_read_lock,
552 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
553 .readunlock = rcu_torture_read_unlock,
554 .readlock_held = torture_readlock_not_held,
555 .get_gp_seq = rcu_no_completed,
556 .deferred_free = rcu_busted_torture_deferred_free,
557 .sync = synchronize_rcu_busted,
558 .exp_sync = synchronize_rcu_busted,
559 .call = call_rcu_busted,
568 * Definitions for srcu torture testing.
571 DEFINE_STATIC_SRCU(srcu_ctl);
572 static struct srcu_struct srcu_ctld;
573 static struct srcu_struct *srcu_ctlp = &srcu_ctl;
575 static int srcu_torture_read_lock(void) __acquires(srcu_ctlp)
577 return srcu_read_lock(srcu_ctlp);
581 srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
584 const long uspertick = 1000000 / HZ;
585 const long longdelay = 10;
587 /* We want there to be long-running readers, but not all the time. */
589 delay = torture_random(rrsp) %
590 (nrealreaders * 2 * longdelay * uspertick);
591 if (!delay && in_task()) {
592 schedule_timeout_interruptible(longdelay);
593 rtrsp->rt_delay_jiffies = longdelay;
595 rcu_read_delay(rrsp, rtrsp);
599 static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp)
601 srcu_read_unlock(srcu_ctlp, idx);
604 static int torture_srcu_read_lock_held(void)
606 return srcu_read_lock_held(srcu_ctlp);
609 static unsigned long srcu_torture_completed(void)
611 return srcu_batches_completed(srcu_ctlp);
614 static void srcu_torture_deferred_free(struct rcu_torture *rp)
616 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
619 static void srcu_torture_synchronize(void)
621 synchronize_srcu(srcu_ctlp);
624 static unsigned long srcu_torture_get_gp_state(void)
626 return get_state_synchronize_srcu(srcu_ctlp);
629 static unsigned long srcu_torture_start_gp_poll(void)
631 return start_poll_synchronize_srcu(srcu_ctlp);
634 static bool srcu_torture_poll_gp_state(unsigned long oldstate)
636 return poll_state_synchronize_srcu(srcu_ctlp, oldstate);
639 static void srcu_torture_call(struct rcu_head *head,
642 call_srcu(srcu_ctlp, head, func);
645 static void srcu_torture_barrier(void)
647 srcu_barrier(srcu_ctlp);
650 static void srcu_torture_stats(void)
652 srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG);
655 static void srcu_torture_synchronize_expedited(void)
657 synchronize_srcu_expedited(srcu_ctlp);
660 static struct rcu_torture_ops srcu_ops = {
661 .ttype = SRCU_FLAVOR,
662 .init = rcu_sync_torture_init,
663 .readlock = srcu_torture_read_lock,
664 .read_delay = srcu_read_delay,
665 .readunlock = srcu_torture_read_unlock,
666 .readlock_held = torture_srcu_read_lock_held,
667 .get_gp_seq = srcu_torture_completed,
668 .deferred_free = srcu_torture_deferred_free,
669 .sync = srcu_torture_synchronize,
670 .exp_sync = srcu_torture_synchronize_expedited,
671 .get_gp_state = srcu_torture_get_gp_state,
672 .start_gp_poll = srcu_torture_start_gp_poll,
673 .poll_gp_state = srcu_torture_poll_gp_state,
674 .call = srcu_torture_call,
675 .cb_barrier = srcu_torture_barrier,
676 .stats = srcu_torture_stats,
677 .cbflood_max = 50000,
679 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
683 static void srcu_torture_init(void)
685 rcu_sync_torture_init();
686 WARN_ON(init_srcu_struct(&srcu_ctld));
687 srcu_ctlp = &srcu_ctld;
690 static void srcu_torture_cleanup(void)
692 cleanup_srcu_struct(&srcu_ctld);
693 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
696 /* As above, but dynamically allocated. */
697 static struct rcu_torture_ops srcud_ops = {
698 .ttype = SRCU_FLAVOR,
699 .init = srcu_torture_init,
700 .cleanup = srcu_torture_cleanup,
701 .readlock = srcu_torture_read_lock,
702 .read_delay = srcu_read_delay,
703 .readunlock = srcu_torture_read_unlock,
704 .readlock_held = torture_srcu_read_lock_held,
705 .get_gp_seq = srcu_torture_completed,
706 .deferred_free = srcu_torture_deferred_free,
707 .sync = srcu_torture_synchronize,
708 .exp_sync = srcu_torture_synchronize_expedited,
709 .call = srcu_torture_call,
710 .cb_barrier = srcu_torture_barrier,
711 .stats = srcu_torture_stats,
712 .cbflood_max = 50000,
714 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
718 /* As above, but broken due to inappropriate reader extension. */
719 static struct rcu_torture_ops busted_srcud_ops = {
720 .ttype = SRCU_FLAVOR,
721 .init = srcu_torture_init,
722 .cleanup = srcu_torture_cleanup,
723 .readlock = srcu_torture_read_lock,
724 .read_delay = rcu_read_delay,
725 .readunlock = srcu_torture_read_unlock,
726 .readlock_held = torture_srcu_read_lock_held,
727 .get_gp_seq = srcu_torture_completed,
728 .deferred_free = srcu_torture_deferred_free,
729 .sync = srcu_torture_synchronize,
730 .exp_sync = srcu_torture_synchronize_expedited,
731 .call = srcu_torture_call,
732 .cb_barrier = srcu_torture_barrier,
733 .stats = srcu_torture_stats,
735 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
736 .extendables = RCUTORTURE_MAX_EXTEND,
737 .name = "busted_srcud"
741 * Definitions for RCU-tasks torture testing.
744 static int tasks_torture_read_lock(void)
749 static void tasks_torture_read_unlock(int idx)
753 static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
755 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
758 static void synchronize_rcu_mult_test(void)
760 synchronize_rcu_mult(call_rcu_tasks, call_rcu);
763 static struct rcu_torture_ops tasks_ops = {
764 .ttype = RCU_TASKS_FLAVOR,
765 .init = rcu_sync_torture_init,
766 .readlock = tasks_torture_read_lock,
767 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
768 .readunlock = tasks_torture_read_unlock,
769 .get_gp_seq = rcu_no_completed,
770 .deferred_free = rcu_tasks_torture_deferred_free,
771 .sync = synchronize_rcu_tasks,
772 .exp_sync = synchronize_rcu_mult_test,
773 .call = call_rcu_tasks,
774 .cb_barrier = rcu_barrier_tasks,
775 .gp_kthread_dbg = show_rcu_tasks_classic_gp_kthread,
784 * Definitions for trivial CONFIG_PREEMPT=n-only torture testing.
785 * This implementation does not necessarily work well with CPU hotplug.
788 static void synchronize_rcu_trivial(void)
792 for_each_online_cpu(cpu) {
793 rcutorture_sched_setaffinity(current->pid, cpumask_of(cpu));
794 WARN_ON_ONCE(raw_smp_processor_id() != cpu);
798 static int rcu_torture_read_lock_trivial(void) __acquires(RCU)
804 static void rcu_torture_read_unlock_trivial(int idx) __releases(RCU)
809 static struct rcu_torture_ops trivial_ops = {
810 .ttype = RCU_TRIVIAL_FLAVOR,
811 .init = rcu_sync_torture_init,
812 .readlock = rcu_torture_read_lock_trivial,
813 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
814 .readunlock = rcu_torture_read_unlock_trivial,
815 .readlock_held = torture_readlock_not_held,
816 .get_gp_seq = rcu_no_completed,
817 .sync = synchronize_rcu_trivial,
818 .exp_sync = synchronize_rcu_trivial,
826 * Definitions for rude RCU-tasks torture testing.
829 static void rcu_tasks_rude_torture_deferred_free(struct rcu_torture *p)
831 call_rcu_tasks_rude(&p->rtort_rcu, rcu_torture_cb);
834 static struct rcu_torture_ops tasks_rude_ops = {
835 .ttype = RCU_TASKS_RUDE_FLAVOR,
836 .init = rcu_sync_torture_init,
837 .readlock = rcu_torture_read_lock_trivial,
838 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
839 .readunlock = rcu_torture_read_unlock_trivial,
840 .get_gp_seq = rcu_no_completed,
841 .deferred_free = rcu_tasks_rude_torture_deferred_free,
842 .sync = synchronize_rcu_tasks_rude,
843 .exp_sync = synchronize_rcu_tasks_rude,
844 .call = call_rcu_tasks_rude,
845 .cb_barrier = rcu_barrier_tasks_rude,
846 .gp_kthread_dbg = show_rcu_tasks_rude_gp_kthread,
847 .cbflood_max = 50000,
855 * Definitions for tracing RCU-tasks torture testing.
858 static int tasks_tracing_torture_read_lock(void)
860 rcu_read_lock_trace();
864 static void tasks_tracing_torture_read_unlock(int idx)
866 rcu_read_unlock_trace();
869 static void rcu_tasks_tracing_torture_deferred_free(struct rcu_torture *p)
871 call_rcu_tasks_trace(&p->rtort_rcu, rcu_torture_cb);
874 static struct rcu_torture_ops tasks_tracing_ops = {
875 .ttype = RCU_TASKS_TRACING_FLAVOR,
876 .init = rcu_sync_torture_init,
877 .readlock = tasks_tracing_torture_read_lock,
878 .read_delay = srcu_read_delay, /* just reuse srcu's version. */
879 .readunlock = tasks_tracing_torture_read_unlock,
880 .readlock_held = rcu_read_lock_trace_held,
881 .get_gp_seq = rcu_no_completed,
882 .deferred_free = rcu_tasks_tracing_torture_deferred_free,
883 .sync = synchronize_rcu_tasks_trace,
884 .exp_sync = synchronize_rcu_tasks_trace,
885 .call = call_rcu_tasks_trace,
886 .cb_barrier = rcu_barrier_tasks_trace,
887 .gp_kthread_dbg = show_rcu_tasks_trace_gp_kthread,
888 .cbflood_max = 50000,
893 .name = "tasks-tracing"
896 static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old)
898 if (!cur_ops->gp_diff)
900 return cur_ops->gp_diff(new, old);
904 * RCU torture priority-boost testing. Runs one real-time thread per
905 * CPU for moderate bursts, repeatedly starting grace periods and waiting
906 * for them to complete. If a given grace period takes too long, we assume
907 * that priority inversion has occurred.
910 static int old_rt_runtime = -1;
912 static void rcu_torture_disable_rt_throttle(void)
915 * Disable RT throttling so that rcutorture's boost threads don't get
916 * throttled. Only possible if rcutorture is built-in otherwise the
917 * user should manually do this by setting the sched_rt_period_us and
918 * sched_rt_runtime sysctls.
920 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime != -1)
923 old_rt_runtime = sysctl_sched_rt_runtime;
924 sysctl_sched_rt_runtime = -1;
927 static void rcu_torture_enable_rt_throttle(void)
929 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime == -1)
932 sysctl_sched_rt_runtime = old_rt_runtime;
936 static bool rcu_torture_boost_failed(unsigned long gp_state, unsigned long *start)
940 unsigned long end = jiffies;
943 static unsigned long last_persist;
945 unsigned long mininterval = test_boost_duration * HZ - HZ / 2;
947 if (end - *start > mininterval) {
948 // Recheck after checking time to avoid false positives.
949 smp_mb(); // Time check before grace-period check.
950 if (cur_ops->poll_gp_state(gp_state))
951 return false; // passed, though perhaps just barely
952 if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, &cpu)) {
953 // At most one persisted message per boost test.
955 lp = READ_ONCE(last_persist);
956 if (time_after(j, lp + mininterval) && cmpxchg(&last_persist, lp, j) == lp)
957 pr_info("Boost inversion persisted: No QS from CPU %d\n", cpu);
958 return false; // passed on a technicality
960 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
961 n_rcu_torture_boost_failure++;
962 if (!xchg(&dbg_done, 1) && cur_ops->gp_kthread_dbg) {
963 pr_info("Boost inversion thread ->rt_priority %u gp_state %lu jiffies %lu\n",
964 current->rt_priority, gp_state, end - *start);
965 cur_ops->gp_kthread_dbg();
966 // Recheck after print to flag grace period ending during splat.
967 gp_done = cur_ops->poll_gp_state(gp_state);
968 pr_info("Boost inversion: GP %lu %s.\n", gp_state,
969 gp_done ? "ended already" : "still pending");
973 return true; // failed
974 } else if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, NULL)) {
978 return false; // passed
981 static int rcu_torture_boost(void *arg)
983 unsigned long endtime;
984 unsigned long gp_state;
985 unsigned long gp_state_time;
986 unsigned long oldstarttime;
988 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
990 /* Set real-time priority. */
991 sched_set_fifo_low(current);
993 /* Each pass through the following loop does one boost-test cycle. */
995 bool failed = false; // Test failed already in this test interval
996 bool gp_initiated = false;
998 if (kthread_should_stop())
1001 /* Wait for the next test interval. */
1002 oldstarttime = READ_ONCE(boost_starttime);
1003 while (time_before(jiffies, oldstarttime)) {
1004 schedule_timeout_interruptible(oldstarttime - jiffies);
1005 if (stutter_wait("rcu_torture_boost"))
1006 sched_set_fifo_low(current);
1007 if (torture_must_stop())
1011 // Do one boost-test interval.
1012 endtime = oldstarttime + test_boost_duration * HZ;
1013 while (time_before(jiffies, endtime)) {
1014 // Has current GP gone too long?
1015 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state))
1016 failed = rcu_torture_boost_failed(gp_state, &gp_state_time);
1017 // If we don't have a grace period in flight, start one.
1018 if (!gp_initiated || cur_ops->poll_gp_state(gp_state)) {
1019 gp_state = cur_ops->start_gp_poll();
1020 gp_initiated = true;
1021 gp_state_time = jiffies;
1023 if (stutter_wait("rcu_torture_boost")) {
1024 sched_set_fifo_low(current);
1025 // If the grace period already ended,
1026 // we don't know when that happened, so
1028 if (cur_ops->poll_gp_state(gp_state))
1029 gp_initiated = false;
1031 if (torture_must_stop())
1035 // In case the grace period extended beyond the end of the loop.
1036 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state))
1037 rcu_torture_boost_failed(gp_state, &gp_state_time);
1040 * Set the start time of the next test interval.
1041 * Yes, this is vulnerable to long delays, but such
1042 * delays simply cause a false negative for the next
1043 * interval. Besides, we are running at RT priority,
1044 * so delays should be relatively rare.
1046 while (oldstarttime == READ_ONCE(boost_starttime) && !kthread_should_stop()) {
1047 if (mutex_trylock(&boost_mutex)) {
1048 if (oldstarttime == boost_starttime) {
1049 WRITE_ONCE(boost_starttime,
1050 jiffies + test_boost_interval * HZ);
1051 n_rcu_torture_boosts++;
1053 mutex_unlock(&boost_mutex);
1056 schedule_timeout_uninterruptible(1);
1059 /* Go do the stutter. */
1060 checkwait: if (stutter_wait("rcu_torture_boost"))
1061 sched_set_fifo_low(current);
1062 } while (!torture_must_stop());
1064 /* Clean up and exit. */
1065 while (!kthread_should_stop()) {
1066 torture_shutdown_absorb("rcu_torture_boost");
1067 schedule_timeout_uninterruptible(1);
1069 torture_kthread_stopping("rcu_torture_boost");
1074 * RCU torture force-quiescent-state kthread. Repeatedly induces
1075 * bursts of calls to force_quiescent_state(), increasing the probability
1076 * of occurrence of some important types of race conditions.
1079 rcu_torture_fqs(void *arg)
1081 unsigned long fqs_resume_time;
1082 int fqs_burst_remaining;
1083 int oldnice = task_nice(current);
1085 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
1087 fqs_resume_time = jiffies + fqs_stutter * HZ;
1088 while (time_before(jiffies, fqs_resume_time) &&
1089 !kthread_should_stop()) {
1090 schedule_timeout_interruptible(1);
1092 fqs_burst_remaining = fqs_duration;
1093 while (fqs_burst_remaining > 0 &&
1094 !kthread_should_stop()) {
1096 udelay(fqs_holdoff);
1097 fqs_burst_remaining -= fqs_holdoff;
1099 if (stutter_wait("rcu_torture_fqs"))
1100 sched_set_normal(current, oldnice);
1101 } while (!torture_must_stop());
1102 torture_kthread_stopping("rcu_torture_fqs");
1106 // Used by writers to randomly choose from the available grace-period
1107 // primitives. The only purpose of the initialization is to size the array.
1108 static int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC, RTWS_COND_GET, RTWS_POLL_GET, RTWS_SYNC };
1109 static int nsynctypes;
1112 * Determine which grace-period primitives are available.
1114 static void rcu_torture_write_types(void)
1116 bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal;
1117 bool gp_poll1 = gp_poll, gp_sync1 = gp_sync;
1119 /* Initialize synctype[] array. If none set, take default. */
1120 if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_poll1 && !gp_sync1)
1121 gp_cond1 = gp_exp1 = gp_normal1 = gp_poll1 = gp_sync1 = true;
1122 if (gp_cond1 && cur_ops->get_gp_state && cur_ops->cond_sync) {
1123 synctype[nsynctypes++] = RTWS_COND_GET;
1124 pr_info("%s: Testing conditional GPs.\n", __func__);
1125 } else if (gp_cond && (!cur_ops->get_gp_state || !cur_ops->cond_sync)) {
1126 pr_alert("%s: gp_cond without primitives.\n", __func__);
1128 if (gp_exp1 && cur_ops->exp_sync) {
1129 synctype[nsynctypes++] = RTWS_EXP_SYNC;
1130 pr_info("%s: Testing expedited GPs.\n", __func__);
1131 } else if (gp_exp && !cur_ops->exp_sync) {
1132 pr_alert("%s: gp_exp without primitives.\n", __func__);
1134 if (gp_normal1 && cur_ops->deferred_free) {
1135 synctype[nsynctypes++] = RTWS_DEF_FREE;
1136 pr_info("%s: Testing asynchronous GPs.\n", __func__);
1137 } else if (gp_normal && !cur_ops->deferred_free) {
1138 pr_alert("%s: gp_normal without primitives.\n", __func__);
1140 if (gp_poll1 && cur_ops->start_gp_poll && cur_ops->poll_gp_state) {
1141 synctype[nsynctypes++] = RTWS_POLL_GET;
1142 pr_info("%s: Testing polling GPs.\n", __func__);
1143 } else if (gp_poll && (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)) {
1144 pr_alert("%s: gp_poll without primitives.\n", __func__);
1146 if (gp_sync1 && cur_ops->sync) {
1147 synctype[nsynctypes++] = RTWS_SYNC;
1148 pr_info("%s: Testing normal GPs.\n", __func__);
1149 } else if (gp_sync && !cur_ops->sync) {
1150 pr_alert("%s: gp_sync without primitives.\n", __func__);
1155 * RCU torture writer kthread. Repeatedly substitutes a new structure
1156 * for that pointed to by rcu_torture_current, freeing the old structure
1157 * after a series of grace periods (the "pipeline").
1160 rcu_torture_writer(void *arg)
1163 bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
1164 unsigned long cookie;
1166 unsigned long gp_snap;
1169 int oldnice = task_nice(current);
1170 struct rcu_torture *rp;
1171 struct rcu_torture *old_rp;
1172 static DEFINE_TORTURE_RANDOM(rand);
1173 bool stutter_waited;
1175 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
1177 pr_alert("%s" TORTURE_FLAG
1178 " GP expediting controlled from boot/sysfs for %s.\n",
1179 torture_type, cur_ops->name);
1180 if (WARN_ONCE(nsynctypes == 0,
1181 "rcu_torture_writer: No update-side primitives.\n")) {
1183 * No updates primitives, so don't try updating.
1184 * The resulting test won't be testing much, hence the
1185 * above WARN_ONCE().
1187 rcu_torture_writer_state = RTWS_STOPPING;
1188 torture_kthread_stopping("rcu_torture_writer");
1192 rcu_torture_writer_state = RTWS_FIXED_DELAY;
1193 torture_hrtimeout_us(500, 1000, &rand);
1194 rp = rcu_torture_alloc();
1197 rp->rtort_pipe_count = 0;
1198 rcu_torture_writer_state = RTWS_DELAY;
1199 udelay(torture_random(&rand) & 0x3ff);
1200 rcu_torture_writer_state = RTWS_REPLACE;
1201 old_rp = rcu_dereference_check(rcu_torture_current,
1202 current == writer_task);
1203 rp->rtort_mbtest = 1;
1204 rcu_assign_pointer(rcu_torture_current, rp);
1205 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
1207 i = old_rp->rtort_pipe_count;
1208 if (i > RCU_TORTURE_PIPE_LEN)
1209 i = RCU_TORTURE_PIPE_LEN;
1210 atomic_inc(&rcu_torture_wcount[i]);
1211 WRITE_ONCE(old_rp->rtort_pipe_count,
1212 old_rp->rtort_pipe_count + 1);
1213 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) {
1214 idx = cur_ops->readlock();
1215 cookie = cur_ops->get_gp_state();
1216 WARN_ONCE(rcu_torture_writer_state != RTWS_DEF_FREE &&
1217 cur_ops->poll_gp_state(cookie),
1218 "%s: Cookie check 1 failed %s(%d) %lu->%lu\n",
1220 rcu_torture_writer_state_getname(),
1221 rcu_torture_writer_state,
1222 cookie, cur_ops->get_gp_state());
1223 cur_ops->readunlock(idx);
1225 switch (synctype[torture_random(&rand) % nsynctypes]) {
1227 rcu_torture_writer_state = RTWS_DEF_FREE;
1228 cur_ops->deferred_free(old_rp);
1231 rcu_torture_writer_state = RTWS_EXP_SYNC;
1232 cur_ops->exp_sync();
1233 rcu_torture_pipe_update(old_rp);
1236 rcu_torture_writer_state = RTWS_COND_GET;
1237 gp_snap = cur_ops->get_gp_state();
1238 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1239 rcu_torture_writer_state = RTWS_COND_SYNC;
1240 cur_ops->cond_sync(gp_snap);
1241 rcu_torture_pipe_update(old_rp);
1244 rcu_torture_writer_state = RTWS_POLL_GET;
1245 gp_snap = cur_ops->start_gp_poll();
1246 rcu_torture_writer_state = RTWS_POLL_WAIT;
1247 while (!cur_ops->poll_gp_state(gp_snap))
1248 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1250 rcu_torture_pipe_update(old_rp);
1253 rcu_torture_writer_state = RTWS_SYNC;
1255 rcu_torture_pipe_update(old_rp);
1262 WRITE_ONCE(rcu_torture_current_version,
1263 rcu_torture_current_version + 1);
1264 /* Cycle through nesting levels of rcu_expedite_gp() calls. */
1266 !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
1267 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
1268 if (expediting >= 0)
1271 rcu_unexpedite_gp();
1272 if (++expediting > 3)
1273 expediting = -expediting;
1274 } else if (!can_expedite) { /* Disabled during boot, recheck. */
1275 can_expedite = !rcu_gp_is_expedited() &&
1276 !rcu_gp_is_normal();
1278 rcu_torture_writer_state = RTWS_STUTTER;
1279 boot_ended = rcu_inkernel_boot_has_ended();
1280 stutter_waited = stutter_wait("rcu_torture_writer");
1281 if (stutter_waited &&
1282 !atomic_read(&rcu_fwd_cb_nodelay) &&
1283 !cur_ops->slow_gps &&
1284 !torture_must_stop() &&
1286 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++)
1287 if (list_empty(&rcu_tortures[i].rtort_free) &&
1288 rcu_access_pointer(rcu_torture_current) !=
1290 rcu_ftrace_dump(DUMP_ALL);
1291 WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count);
1294 sched_set_normal(current, oldnice);
1295 } while (!torture_must_stop());
1296 rcu_torture_current = NULL; // Let stats task know that we are done.
1297 /* Reset expediting back to unexpedited. */
1299 expediting = -expediting;
1300 while (can_expedite && expediting++ < 0)
1301 rcu_unexpedite_gp();
1302 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
1304 pr_alert("%s" TORTURE_FLAG
1305 " Dynamic grace-period expediting was disabled.\n",
1307 rcu_torture_writer_state = RTWS_STOPPING;
1308 torture_kthread_stopping("rcu_torture_writer");
1313 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
1314 * delay between calls.
1317 rcu_torture_fakewriter(void *arg)
1319 unsigned long gp_snap;
1320 DEFINE_TORTURE_RANDOM(rand);
1322 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1323 set_user_nice(current, MAX_NICE);
1326 torture_hrtimeout_jiffies(torture_random(&rand) % 10, &rand);
1327 if (cur_ops->cb_barrier != NULL &&
1328 torture_random(&rand) % (nfakewriters * 8) == 0) {
1329 cur_ops->cb_barrier();
1331 switch (synctype[torture_random(&rand) % nsynctypes]) {
1335 cur_ops->exp_sync();
1338 gp_snap = cur_ops->get_gp_state();
1339 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1340 cur_ops->cond_sync(gp_snap);
1343 gp_snap = cur_ops->start_gp_poll();
1344 while (!cur_ops->poll_gp_state(gp_snap)) {
1345 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1357 stutter_wait("rcu_torture_fakewriter");
1358 } while (!torture_must_stop());
1360 torture_kthread_stopping("rcu_torture_fakewriter");
1364 static void rcu_torture_timer_cb(struct rcu_head *rhp)
1369 // Set up and carry out testing of RCU's global memory ordering
1370 static void rcu_torture_reader_do_mbchk(long myid, struct rcu_torture *rtp,
1371 struct torture_random_state *trsp)
1373 unsigned long loops;
1374 int noc = torture_num_online_cpus();
1377 struct rcu_torture_reader_check *rtrcp; // Me.
1378 struct rcu_torture_reader_check *rtrcp_assigner; // Assigned us to do checking.
1379 struct rcu_torture_reader_check *rtrcp_chked; // Reader being checked.
1380 struct rcu_torture_reader_check *rtrcp_chker; // Reader doing checking when not me.
1383 return; // Don't try this from timer handlers.
1385 // Increment my counter.
1386 rtrcp = &rcu_torture_reader_mbchk[myid];
1387 WRITE_ONCE(rtrcp->rtc_myloops, rtrcp->rtc_myloops + 1);
1389 // Attempt to assign someone else some checking work.
1390 rdrchked = torture_random(trsp) % nrealreaders;
1391 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked];
1392 rdrchker = torture_random(trsp) % nrealreaders;
1393 rtrcp_chker = &rcu_torture_reader_mbchk[rdrchker];
1394 if (rdrchked != myid && rdrchked != rdrchker && noc >= rdrchked && noc >= rdrchker &&
1395 smp_load_acquire(&rtrcp->rtc_chkrdr) < 0 && // Pairs with smp_store_release below.
1396 !READ_ONCE(rtp->rtort_chkp) &&
1397 !smp_load_acquire(&rtrcp_chker->rtc_assigner)) { // Pairs with smp_store_release below.
1398 rtrcp->rtc_chkloops = READ_ONCE(rtrcp_chked->rtc_myloops);
1399 WARN_ON_ONCE(rtrcp->rtc_chkrdr >= 0);
1400 rtrcp->rtc_chkrdr = rdrchked;
1401 WARN_ON_ONCE(rtrcp->rtc_ready); // This gets set after the grace period ends.
1402 if (cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, NULL, rtrcp) ||
1403 cmpxchg_relaxed(&rtp->rtort_chkp, NULL, rtrcp))
1404 (void)cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, rtrcp, NULL); // Back out.
1407 // If assigned some completed work, do it!
1408 rtrcp_assigner = READ_ONCE(rtrcp->rtc_assigner);
1409 if (!rtrcp_assigner || !smp_load_acquire(&rtrcp_assigner->rtc_ready))
1410 return; // No work or work not yet ready.
1411 rdrchked = rtrcp_assigner->rtc_chkrdr;
1412 if (WARN_ON_ONCE(rdrchked < 0))
1414 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked];
1415 loops = READ_ONCE(rtrcp_chked->rtc_myloops);
1416 atomic_inc(&n_rcu_torture_mbchk_tries);
1417 if (ULONG_CMP_LT(loops, rtrcp_assigner->rtc_chkloops))
1418 atomic_inc(&n_rcu_torture_mbchk_fail);
1419 rtrcp_assigner->rtc_chkloops = loops + ULONG_MAX / 2;
1420 rtrcp_assigner->rtc_ready = 0;
1421 smp_store_release(&rtrcp->rtc_assigner, NULL); // Someone else can assign us work.
1422 smp_store_release(&rtrcp_assigner->rtc_chkrdr, -1); // Assigner can again assign.
1426 * Do one extension of an RCU read-side critical section using the
1427 * current reader state in readstate (set to zero for initial entry
1428 * to extended critical section), set the new state as specified by
1429 * newstate (set to zero for final exit from extended critical section),
1430 * and random-number-generator state in trsp. If this is neither the
1431 * beginning or end of the critical section and if there was actually a
1432 * change, do a ->read_delay().
1434 static void rcutorture_one_extend(int *readstate, int newstate,
1435 struct torture_random_state *trsp,
1436 struct rt_read_seg *rtrsp)
1438 unsigned long flags;
1441 int idxold1 = *readstate;
1442 int idxold2 = idxold1;
1443 int statesnew = ~*readstate & newstate;
1444 int statesold = *readstate & ~newstate;
1446 WARN_ON_ONCE(idxold2 < 0);
1447 WARN_ON_ONCE((idxold2 >> RCUTORTURE_RDR_SHIFT_2) > 1);
1448 rtrsp->rt_readstate = newstate;
1450 /* First, put new protection in place to avoid critical-section gap. */
1451 if (statesnew & RCUTORTURE_RDR_BH)
1453 if (statesnew & RCUTORTURE_RDR_RBH)
1455 if (statesnew & RCUTORTURE_RDR_IRQ)
1456 local_irq_disable();
1457 if (statesnew & RCUTORTURE_RDR_PREEMPT)
1459 if (statesnew & RCUTORTURE_RDR_SCHED)
1460 rcu_read_lock_sched();
1461 if (statesnew & RCUTORTURE_RDR_RCU_1)
1462 idxnew1 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_1;
1463 if (statesnew & RCUTORTURE_RDR_RCU_2)
1464 idxnew2 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_2;
1467 * Next, remove old protection, in decreasing order of strength
1468 * to avoid unlock paths that aren't safe in the stronger
1469 * context. Namely: BH can not be enabled with disabled interrupts.
1470 * Additionally PREEMPT_RT requires that BH is enabled in preemptible
1473 if (statesold & RCUTORTURE_RDR_IRQ)
1475 if (statesold & RCUTORTURE_RDR_PREEMPT)
1477 if (statesold & RCUTORTURE_RDR_SCHED)
1478 rcu_read_unlock_sched();
1479 if (statesold & RCUTORTURE_RDR_BH)
1481 if (statesold & RCUTORTURE_RDR_RBH)
1482 rcu_read_unlock_bh();
1483 if (statesold & RCUTORTURE_RDR_RCU_2) {
1484 cur_ops->readunlock((idxold2 >> RCUTORTURE_RDR_SHIFT_2) & 0x1);
1485 WARN_ON_ONCE(idxnew2 != -1);
1488 if (statesold & RCUTORTURE_RDR_RCU_1) {
1491 lockit = !cur_ops->no_pi_lock && !statesnew && !(torture_random(trsp) & 0xffff);
1493 raw_spin_lock_irqsave(¤t->pi_lock, flags);
1494 cur_ops->readunlock((idxold1 >> RCUTORTURE_RDR_SHIFT_1) & 0x1);
1495 WARN_ON_ONCE(idxnew1 != -1);
1498 raw_spin_unlock_irqrestore(¤t->pi_lock, flags);
1501 /* Delay if neither beginning nor end and there was a change. */
1502 if ((statesnew || statesold) && *readstate && newstate)
1503 cur_ops->read_delay(trsp, rtrsp);
1505 /* Update the reader state. */
1507 idxnew1 = idxold1 & RCUTORTURE_RDR_MASK_1;
1508 WARN_ON_ONCE(idxnew1 < 0);
1509 if (WARN_ON_ONCE((idxnew1 >> RCUTORTURE_RDR_SHIFT_1) > 1))
1510 pr_info("Unexpected idxnew1 value of %#x\n", idxnew1);
1512 idxnew2 = idxold2 & RCUTORTURE_RDR_MASK_2;
1513 WARN_ON_ONCE(idxnew2 < 0);
1514 WARN_ON_ONCE((idxnew2 >> RCUTORTURE_RDR_SHIFT_2) > 1);
1515 *readstate = idxnew1 | idxnew2 | newstate;
1516 WARN_ON_ONCE(*readstate < 0);
1517 if (WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT_2) > 1))
1518 pr_info("Unexpected idxnew2 value of %#x\n", idxnew2);
1521 /* Return the biggest extendables mask given current RCU and boot parameters. */
1522 static int rcutorture_extend_mask_max(void)
1526 WARN_ON_ONCE(extendables & ~RCUTORTURE_MAX_EXTEND);
1527 mask = extendables & RCUTORTURE_MAX_EXTEND & cur_ops->extendables;
1528 mask = mask | RCUTORTURE_RDR_RCU_1 | RCUTORTURE_RDR_RCU_2;
1532 /* Return a random protection state mask, but with at least one bit set. */
1534 rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp)
1536 int mask = rcutorture_extend_mask_max();
1537 unsigned long randmask1 = torture_random(trsp) >> 8;
1538 unsigned long randmask2 = randmask1 >> 3;
1539 unsigned long preempts = RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED;
1540 unsigned long preempts_irq = preempts | RCUTORTURE_RDR_IRQ;
1541 unsigned long bhs = RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH;
1543 WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT_1);
1544 /* Mostly only one bit (need preemption!), sometimes lots of bits. */
1545 if (!(randmask1 & 0x7))
1546 mask = mask & randmask2;
1548 mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS));
1550 // Can't have nested RCU reader without outer RCU reader.
1551 if (!(mask & RCUTORTURE_RDR_RCU_1) && (mask & RCUTORTURE_RDR_RCU_2)) {
1552 if (oldmask & RCUTORTURE_RDR_RCU_1)
1553 mask &= ~RCUTORTURE_RDR_RCU_2;
1555 mask |= RCUTORTURE_RDR_RCU_1;
1559 * Can't enable bh w/irq disabled.
1561 if (mask & RCUTORTURE_RDR_IRQ)
1562 mask |= oldmask & bhs;
1565 * Ideally these sequences would be detected in debug builds
1566 * (regardless of RT), but until then don't stop testing
1569 if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
1570 /* Can't modify BH in atomic context */
1571 if (oldmask & preempts_irq)
1573 if ((oldmask | mask) & preempts_irq)
1574 mask |= oldmask & bhs;
1577 return mask ?: RCUTORTURE_RDR_RCU_1;
1581 * Do a randomly selected number of extensions of an existing RCU read-side
1584 static struct rt_read_seg *
1585 rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp,
1586 struct rt_read_seg *rtrsp)
1590 int mask = rcutorture_extend_mask_max();
1592 WARN_ON_ONCE(!*readstate); /* -Existing- RCU read-side critsect! */
1593 if (!((mask - 1) & mask))
1594 return rtrsp; /* Current RCU reader not extendable. */
1595 /* Bias towards larger numbers of loops. */
1596 i = (torture_random(trsp) >> 3);
1597 i = ((i | (i >> 3)) & RCUTORTURE_RDR_MAX_LOOPS) + 1;
1598 for (j = 0; j < i; j++) {
1599 mask = rcutorture_extend_mask(*readstate, trsp);
1600 rcutorture_one_extend(readstate, mask, trsp, &rtrsp[j]);
1606 * Do one read-side critical section, returning false if there was
1607 * no data to read. Can be invoked both from process context and
1608 * from a timer handler.
1610 static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid)
1612 unsigned long cookie;
1614 unsigned long started;
1615 unsigned long completed;
1617 struct rcu_torture *p;
1620 struct rt_read_seg rtseg[RCUTORTURE_RDR_MAX_SEGS] = { { 0 } };
1621 struct rt_read_seg *rtrsp = &rtseg[0];
1622 struct rt_read_seg *rtrsp1;
1623 unsigned long long ts;
1625 WARN_ON_ONCE(!rcu_is_watching());
1626 newstate = rcutorture_extend_mask(readstate, trsp);
1627 rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++);
1628 if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
1629 cookie = cur_ops->get_gp_state();
1630 started = cur_ops->get_gp_seq();
1631 ts = rcu_trace_clock_local();
1632 p = rcu_dereference_check(rcu_torture_current,
1633 !cur_ops->readlock_held || cur_ops->readlock_held());
1635 /* Wait for rcu_torture_writer to get underway */
1636 rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
1639 if (p->rtort_mbtest == 0)
1640 atomic_inc(&n_rcu_torture_mberror);
1641 rcu_torture_reader_do_mbchk(myid, p, trsp);
1642 rtrsp = rcutorture_loop_extend(&readstate, trsp, rtrsp);
1644 pipe_count = READ_ONCE(p->rtort_pipe_count);
1645 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1646 /* Should not happen, but... */
1647 pipe_count = RCU_TORTURE_PIPE_LEN;
1649 completed = cur_ops->get_gp_seq();
1650 if (pipe_count > 1) {
1651 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
1652 ts, started, completed);
1653 rcu_ftrace_dump(DUMP_ALL);
1655 __this_cpu_inc(rcu_torture_count[pipe_count]);
1656 completed = rcutorture_seq_diff(completed, started);
1657 if (completed > RCU_TORTURE_PIPE_LEN) {
1658 /* Should not happen, but... */
1659 completed = RCU_TORTURE_PIPE_LEN;
1661 __this_cpu_inc(rcu_torture_batch[completed]);
1663 if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
1664 WARN_ONCE(cur_ops->poll_gp_state(cookie),
1665 "%s: Cookie check 2 failed %s(%d) %lu->%lu\n",
1667 rcu_torture_writer_state_getname(),
1668 rcu_torture_writer_state,
1669 cookie, cur_ops->get_gp_state());
1670 rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
1671 WARN_ON_ONCE(readstate);
1672 // This next splat is expected behavior if leakpointer, especially
1673 // for CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels.
1674 WARN_ON_ONCE(leakpointer && READ_ONCE(p->rtort_pipe_count) > 1);
1676 /* If error or close call, record the sequence of reader protections. */
1677 if ((pipe_count > 1 || completed > 1) && !xchg(&err_segs_recorded, 1)) {
1679 for (rtrsp1 = &rtseg[0]; rtrsp1 < rtrsp; rtrsp1++)
1680 err_segs[i++] = *rtrsp1;
1687 static DEFINE_TORTURE_RANDOM_PERCPU(rcu_torture_timer_rand);
1690 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
1691 * incrementing the corresponding element of the pipeline array. The
1692 * counter in the element should never be greater than 1, otherwise, the
1693 * RCU implementation is broken.
1695 static void rcu_torture_timer(struct timer_list *unused)
1697 atomic_long_inc(&n_rcu_torture_timers);
1698 (void)rcu_torture_one_read(this_cpu_ptr(&rcu_torture_timer_rand), -1);
1700 /* Test call_rcu() invocation from interrupt handler. */
1701 if (cur_ops->call) {
1702 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT);
1705 cur_ops->call(rhp, rcu_torture_timer_cb);
1710 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
1711 * incrementing the corresponding element of the pipeline array. The
1712 * counter in the element should never be greater than 1, otherwise, the
1713 * RCU implementation is broken.
1716 rcu_torture_reader(void *arg)
1718 unsigned long lastsleep = jiffies;
1719 long myid = (long)arg;
1720 int mynumonline = myid;
1721 DEFINE_TORTURE_RANDOM(rand);
1722 struct timer_list t;
1724 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
1725 set_user_nice(current, MAX_NICE);
1726 if (irqreader && cur_ops->irq_capable)
1727 timer_setup_on_stack(&t, rcu_torture_timer, 0);
1728 tick_dep_set_task(current, TICK_DEP_BIT_RCU);
1730 if (irqreader && cur_ops->irq_capable) {
1731 if (!timer_pending(&t))
1732 mod_timer(&t, jiffies + 1);
1734 if (!rcu_torture_one_read(&rand, myid) && !torture_must_stop())
1735 schedule_timeout_interruptible(HZ);
1736 if (time_after(jiffies, lastsleep) && !torture_must_stop()) {
1737 torture_hrtimeout_us(500, 1000, &rand);
1738 lastsleep = jiffies + 10;
1740 while (torture_num_online_cpus() < mynumonline && !torture_must_stop())
1741 schedule_timeout_interruptible(HZ / 5);
1742 stutter_wait("rcu_torture_reader");
1743 } while (!torture_must_stop());
1744 if (irqreader && cur_ops->irq_capable) {
1746 destroy_timer_on_stack(&t);
1748 tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
1749 torture_kthread_stopping("rcu_torture_reader");
1754 * Randomly Toggle CPUs' callback-offload state. This uses hrtimers to
1755 * increase race probabilities and fuzzes the interval between toggling.
1757 static int rcu_nocb_toggle(void *arg)
1761 int oldnice = task_nice(current);
1763 DEFINE_TORTURE_RANDOM(rand);
1764 ktime_t toggle_delay;
1765 unsigned long toggle_fuzz;
1766 ktime_t toggle_interval = ms_to_ktime(nocbs_toggle);
1768 VERBOSE_TOROUT_STRING("rcu_nocb_toggle task started");
1769 while (!rcu_inkernel_boot_has_ended())
1770 schedule_timeout_interruptible(HZ / 10);
1771 for_each_online_cpu(cpu)
1773 WARN_ON(maxcpu < 0);
1774 if (toggle_interval > ULONG_MAX)
1775 toggle_fuzz = ULONG_MAX >> 3;
1777 toggle_fuzz = toggle_interval >> 3;
1778 if (toggle_fuzz <= 0)
1779 toggle_fuzz = NSEC_PER_USEC;
1781 r = torture_random(&rand);
1782 cpu = (r >> 4) % (maxcpu + 1);
1784 rcu_nocb_cpu_offload(cpu);
1785 atomic_long_inc(&n_nocb_offload);
1787 rcu_nocb_cpu_deoffload(cpu);
1788 atomic_long_inc(&n_nocb_deoffload);
1790 toggle_delay = torture_random(&rand) % toggle_fuzz + toggle_interval;
1791 set_current_state(TASK_INTERRUPTIBLE);
1792 schedule_hrtimeout(&toggle_delay, HRTIMER_MODE_REL);
1793 if (stutter_wait("rcu_nocb_toggle"))
1794 sched_set_normal(current, oldnice);
1795 } while (!torture_must_stop());
1796 torture_kthread_stopping("rcu_nocb_toggle");
1801 * Print torture statistics. Caller must ensure that there is only
1802 * one call to this function at a given time!!! This is normally
1803 * accomplished by relying on the module system to only have one copy
1804 * of the module loaded, and then by giving the rcu_torture_stats
1805 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1806 * thread is not running).
1809 rcu_torture_stats_print(void)
1813 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1814 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1815 struct rcu_torture *rtcp;
1816 static unsigned long rtcv_snap = ULONG_MAX;
1817 static bool splatted;
1818 struct task_struct *wtp;
1820 for_each_possible_cpu(cpu) {
1821 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1822 pipesummary[i] += READ_ONCE(per_cpu(rcu_torture_count, cpu)[i]);
1823 batchsummary[i] += READ_ONCE(per_cpu(rcu_torture_batch, cpu)[i]);
1826 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
1827 if (pipesummary[i] != 0)
1831 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1832 rtcp = rcu_access_pointer(rcu_torture_current);
1833 pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
1835 rtcp && !rcu_stall_is_suppressed_at_boot() ? "ver" : "VER",
1836 rcu_torture_current_version,
1837 list_empty(&rcu_torture_freelist),
1838 atomic_read(&n_rcu_torture_alloc),
1839 atomic_read(&n_rcu_torture_alloc_fail),
1840 atomic_read(&n_rcu_torture_free));
1841 pr_cont("rtmbe: %d rtmbkf: %d/%d rtbe: %ld rtbke: %ld rtbre: %ld ",
1842 atomic_read(&n_rcu_torture_mberror),
1843 atomic_read(&n_rcu_torture_mbchk_fail), atomic_read(&n_rcu_torture_mbchk_tries),
1844 n_rcu_torture_barrier_error,
1845 n_rcu_torture_boost_ktrerror,
1846 n_rcu_torture_boost_rterror);
1847 pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
1848 n_rcu_torture_boost_failure,
1849 n_rcu_torture_boosts,
1850 atomic_long_read(&n_rcu_torture_timers));
1851 torture_onoff_stats();
1852 pr_cont("barrier: %ld/%ld:%ld ",
1853 data_race(n_barrier_successes),
1854 data_race(n_barrier_attempts),
1855 data_race(n_rcu_torture_barrier_error));
1856 pr_cont("read-exits: %ld ", data_race(n_read_exits)); // Statistic.
1857 pr_cont("nocb-toggles: %ld:%ld\n",
1858 atomic_long_read(&n_nocb_offload), atomic_long_read(&n_nocb_deoffload));
1860 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1861 if (atomic_read(&n_rcu_torture_mberror) ||
1862 atomic_read(&n_rcu_torture_mbchk_fail) ||
1863 n_rcu_torture_barrier_error || n_rcu_torture_boost_ktrerror ||
1864 n_rcu_torture_boost_rterror || n_rcu_torture_boost_failure ||
1866 pr_cont("%s", "!!! ");
1867 atomic_inc(&n_rcu_torture_error);
1868 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mberror));
1869 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mbchk_fail));
1870 WARN_ON_ONCE(n_rcu_torture_barrier_error); // rcu_barrier()
1871 WARN_ON_ONCE(n_rcu_torture_boost_ktrerror); // no boost kthread
1872 WARN_ON_ONCE(n_rcu_torture_boost_rterror); // can't set RT prio
1873 WARN_ON_ONCE(n_rcu_torture_boost_failure); // boost failed (TIMER_SOFTIRQ RT prio?)
1874 WARN_ON_ONCE(i > 1); // Too-short grace period
1876 pr_cont("Reader Pipe: ");
1877 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1878 pr_cont(" %ld", pipesummary[i]);
1881 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1882 pr_cont("Reader Batch: ");
1883 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1884 pr_cont(" %ld", batchsummary[i]);
1887 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1888 pr_cont("Free-Block Circulation: ");
1889 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1890 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
1896 if (rtcv_snap == rcu_torture_current_version &&
1897 rcu_access_pointer(rcu_torture_current) &&
1898 !rcu_stall_is_suppressed()) {
1899 int __maybe_unused flags = 0;
1900 unsigned long __maybe_unused gp_seq = 0;
1902 rcutorture_get_gp_data(cur_ops->ttype,
1904 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp,
1906 wtp = READ_ONCE(writer_task);
1907 pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#x cpu %d\n",
1908 rcu_torture_writer_state_getname(),
1909 rcu_torture_writer_state, gp_seq, flags,
1910 wtp == NULL ? ~0U : wtp->__state,
1911 wtp == NULL ? -1 : (int)task_cpu(wtp));
1912 if (!splatted && wtp) {
1913 sched_show_task(wtp);
1916 if (cur_ops->gp_kthread_dbg)
1917 cur_ops->gp_kthread_dbg();
1918 rcu_ftrace_dump(DUMP_ALL);
1920 rtcv_snap = rcu_torture_current_version;
1924 * Periodically prints torture statistics, if periodic statistics printing
1925 * was specified via the stat_interval module parameter.
1928 rcu_torture_stats(void *arg)
1930 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1932 schedule_timeout_interruptible(stat_interval * HZ);
1933 rcu_torture_stats_print();
1934 torture_shutdown_absorb("rcu_torture_stats");
1935 } while (!torture_must_stop());
1936 torture_kthread_stopping("rcu_torture_stats");
1940 /* Test mem_dump_obj() and friends. */
1941 static void rcu_torture_mem_dump_obj(void)
1943 struct rcu_head *rhp;
1944 struct kmem_cache *kcp;
1947 kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL);
1948 rhp = kmem_cache_alloc(kcp, GFP_KERNEL);
1949 pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z);
1950 pr_alert("mem_dump_obj(ZERO_SIZE_PTR):");
1951 mem_dump_obj(ZERO_SIZE_PTR);
1952 pr_alert("mem_dump_obj(NULL):");
1954 pr_alert("mem_dump_obj(%px):", &rhp);
1956 pr_alert("mem_dump_obj(%px):", rhp);
1958 pr_alert("mem_dump_obj(%px):", &rhp->func);
1959 mem_dump_obj(&rhp->func);
1960 pr_alert("mem_dump_obj(%px):", &z);
1962 kmem_cache_free(kcp, rhp);
1963 kmem_cache_destroy(kcp);
1964 rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
1965 pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
1966 pr_alert("mem_dump_obj(kmalloc %px):", rhp);
1968 pr_alert("mem_dump_obj(kmalloc %px):", &rhp->func);
1969 mem_dump_obj(&rhp->func);
1971 rhp = vmalloc(4096);
1972 pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
1973 pr_alert("mem_dump_obj(vmalloc %px):", rhp);
1975 pr_alert("mem_dump_obj(vmalloc %px):", &rhp->func);
1976 mem_dump_obj(&rhp->func);
1981 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1983 pr_alert("%s" TORTURE_FLAG
1984 "--- %s: nreaders=%d nfakewriters=%d "
1985 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1986 "shuffle_interval=%d stutter=%d irqreader=%d "
1987 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1988 "test_boost=%d/%d test_boost_interval=%d "
1989 "test_boost_duration=%d shutdown_secs=%d "
1990 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d "
1991 "stall_cpu_block=%d "
1993 "onoff_interval=%d onoff_holdoff=%d "
1994 "read_exit_delay=%d read_exit_burst=%d "
1995 "nocbs_nthreads=%d nocbs_toggle=%d\n",
1996 torture_type, tag, nrealreaders, nfakewriters,
1997 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1998 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1999 test_boost, cur_ops->can_boost,
2000 test_boost_interval, test_boost_duration, shutdown_secs,
2001 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff,
2004 onoff_interval, onoff_holdoff,
2005 read_exit_delay, read_exit_burst,
2006 nocbs_nthreads, nocbs_toggle);
2009 static int rcutorture_booster_cleanup(unsigned int cpu)
2011 struct task_struct *t;
2013 if (boost_tasks[cpu] == NULL)
2015 mutex_lock(&boost_mutex);
2016 t = boost_tasks[cpu];
2017 boost_tasks[cpu] = NULL;
2018 rcu_torture_enable_rt_throttle();
2019 mutex_unlock(&boost_mutex);
2021 /* This must be outside of the mutex, otherwise deadlock! */
2022 torture_stop_kthread(rcu_torture_boost, t);
2026 static int rcutorture_booster_init(unsigned int cpu)
2030 if (boost_tasks[cpu] != NULL)
2031 return 0; /* Already created, nothing more to do. */
2033 /* Don't allow time recalculation while creating a new task. */
2034 mutex_lock(&boost_mutex);
2035 rcu_torture_disable_rt_throttle();
2036 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
2037 boost_tasks[cpu] = kthread_run_on_cpu(rcu_torture_boost, NULL,
2038 cpu, "rcu_torture_boost_%u");
2039 if (IS_ERR(boost_tasks[cpu])) {
2040 retval = PTR_ERR(boost_tasks[cpu]);
2041 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
2042 n_rcu_torture_boost_ktrerror++;
2043 boost_tasks[cpu] = NULL;
2044 mutex_unlock(&boost_mutex);
2047 mutex_unlock(&boost_mutex);
2052 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
2053 * induces a CPU stall for the time specified by stall_cpu.
2055 static int rcu_torture_stall(void *args)
2058 unsigned long stop_at;
2060 VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
2061 if (stall_cpu_holdoff > 0) {
2062 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
2063 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
2064 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
2066 if (!kthread_should_stop() && stall_gp_kthread > 0) {
2067 VERBOSE_TOROUT_STRING("rcu_torture_stall begin GP stall");
2068 rcu_gp_set_torture_wait(stall_gp_kthread * HZ);
2069 for (idx = 0; idx < stall_gp_kthread + 2; idx++) {
2070 if (kthread_should_stop())
2072 schedule_timeout_uninterruptible(HZ);
2075 if (!kthread_should_stop() && stall_cpu > 0) {
2076 VERBOSE_TOROUT_STRING("rcu_torture_stall begin CPU stall");
2077 stop_at = ktime_get_seconds() + stall_cpu;
2078 /* RCU CPU stall is expected behavior in following code. */
2079 idx = cur_ops->readlock();
2080 if (stall_cpu_irqsoff)
2081 local_irq_disable();
2082 else if (!stall_cpu_block)
2084 pr_alert("%s start on CPU %d.\n",
2085 __func__, raw_smp_processor_id());
2086 while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(),
2088 if (stall_cpu_block) {
2089 #ifdef CONFIG_PREEMPTION
2092 schedule_timeout_uninterruptible(HZ);
2094 } else if (stall_no_softlockup) {
2095 touch_softlockup_watchdog();
2097 if (stall_cpu_irqsoff)
2099 else if (!stall_cpu_block)
2101 cur_ops->readunlock(idx);
2103 pr_alert("%s end.\n", __func__);
2104 torture_shutdown_absorb("rcu_torture_stall");
2105 while (!kthread_should_stop())
2106 schedule_timeout_interruptible(10 * HZ);
2110 /* Spawn CPU-stall kthread, if stall_cpu specified. */
2111 static int __init rcu_torture_stall_init(void)
2113 if (stall_cpu <= 0 && stall_gp_kthread <= 0)
2115 return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
2118 /* State structure for forward-progress self-propagating RCU callback. */
2119 struct fwd_cb_state {
2125 * Forward-progress self-propagating RCU callback function. Because
2126 * callbacks run from softirq, this function is an implicit RCU read-side
2129 static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp)
2131 struct fwd_cb_state *fcsp = container_of(rhp, struct fwd_cb_state, rh);
2133 if (READ_ONCE(fcsp->stop)) {
2134 WRITE_ONCE(fcsp->stop, 2);
2137 cur_ops->call(&fcsp->rh, rcu_torture_fwd_prog_cb);
2140 /* State for continuous-flood RCU callbacks. */
2143 struct rcu_fwd_cb *rfc_next;
2144 struct rcu_fwd *rfc_rfp;
2148 #define MAX_FWD_CB_JIFFIES (8 * HZ) /* Maximum CB test duration. */
2149 #define MIN_FWD_CB_LAUNDERS 3 /* This many CB invocations to count. */
2150 #define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */
2151 #define FWD_CBS_HIST_DIV 10 /* Histogram buckets/second. */
2152 #define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV))
2154 struct rcu_launder_hist {
2156 unsigned long launder_gp_seq;
2160 spinlock_t rcu_fwd_lock;
2161 struct rcu_fwd_cb *rcu_fwd_cb_head;
2162 struct rcu_fwd_cb **rcu_fwd_cb_tail;
2164 unsigned long rcu_fwd_startat;
2165 struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST];
2166 unsigned long rcu_launder_gp_seq_start;
2170 static DEFINE_MUTEX(rcu_fwd_mutex);
2171 static struct rcu_fwd *rcu_fwds;
2172 static unsigned long rcu_fwd_seq;
2173 static atomic_long_t rcu_fwd_max_cbs;
2174 static bool rcu_fwd_emergency_stop;
2176 static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp)
2179 unsigned long gps_old;
2183 for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--)
2184 if (rfp->n_launders_hist[i].n_launders > 0)
2186 pr_alert("%s: Callback-invocation histogram %d (duration %lu jiffies):",
2187 __func__, rfp->rcu_fwd_id, jiffies - rfp->rcu_fwd_startat);
2188 gps_old = rfp->rcu_launder_gp_seq_start;
2189 for (j = 0; j <= i; j++) {
2190 gps = rfp->n_launders_hist[j].launder_gp_seq;
2191 pr_cont(" %ds/%d: %ld:%ld",
2192 j + 1, FWD_CBS_HIST_DIV,
2193 rfp->n_launders_hist[j].n_launders,
2194 rcutorture_seq_diff(gps, gps_old));
2200 /* Callback function for continuous-flood RCU callbacks. */
2201 static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp)
2203 unsigned long flags;
2205 struct rcu_fwd_cb *rfcp = container_of(rhp, struct rcu_fwd_cb, rh);
2206 struct rcu_fwd_cb **rfcpp;
2207 struct rcu_fwd *rfp = rfcp->rfc_rfp;
2209 rfcp->rfc_next = NULL;
2211 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
2212 rfcpp = rfp->rcu_fwd_cb_tail;
2213 rfp->rcu_fwd_cb_tail = &rfcp->rfc_next;
2214 WRITE_ONCE(*rfcpp, rfcp);
2215 WRITE_ONCE(rfp->n_launders_cb, rfp->n_launders_cb + 1);
2216 i = ((jiffies - rfp->rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV));
2217 if (i >= ARRAY_SIZE(rfp->n_launders_hist))
2218 i = ARRAY_SIZE(rfp->n_launders_hist) - 1;
2219 rfp->n_launders_hist[i].n_launders++;
2220 rfp->n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq();
2221 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
2224 // Give the scheduler a chance, even on nohz_full CPUs.
2225 static void rcu_torture_fwd_prog_cond_resched(unsigned long iter)
2227 if (IS_ENABLED(CONFIG_PREEMPTION) && IS_ENABLED(CONFIG_NO_HZ_FULL)) {
2228 // Real call_rcu() floods hit userspace, so emulate that.
2229 if (need_resched() || (iter & 0xfff))
2233 // No userspace emulation: CB invocation throttles call_rcu()
2238 * Free all callbacks on the rcu_fwd_cb_head list, either because the
2239 * test is over or because we hit an OOM event.
2241 static unsigned long rcu_torture_fwd_prog_cbfree(struct rcu_fwd *rfp)
2243 unsigned long flags;
2244 unsigned long freed = 0;
2245 struct rcu_fwd_cb *rfcp;
2248 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
2249 rfcp = rfp->rcu_fwd_cb_head;
2251 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
2254 rfp->rcu_fwd_cb_head = rfcp->rfc_next;
2255 if (!rfp->rcu_fwd_cb_head)
2256 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head;
2257 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
2260 rcu_torture_fwd_prog_cond_resched(freed);
2261 if (tick_nohz_full_enabled()) {
2262 local_irq_save(flags);
2263 rcu_momentary_dyntick_idle();
2264 local_irq_restore(flags);
2270 /* Carry out need_resched()/cond_resched() forward-progress testing. */
2271 static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp,
2272 int *tested, int *tested_tries)
2276 struct fwd_cb_state fcs;
2281 bool selfpropcb = false;
2282 unsigned long stopat;
2283 static DEFINE_TORTURE_RANDOM(trs);
2285 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
2287 return; // Cannot do need_resched() forward progress testing without ->sync.
2288 if (cur_ops->call && cur_ops->cb_barrier) {
2289 init_rcu_head_on_stack(&fcs.rh);
2293 /* Tight loop containing cond_resched(). */
2294 atomic_inc(&rcu_fwd_cb_nodelay);
2295 cur_ops->sync(); /* Later readers see above write. */
2297 WRITE_ONCE(fcs.stop, 0);
2298 cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb);
2300 cver = READ_ONCE(rcu_torture_current_version);
2301 gps = cur_ops->get_gp_seq();
2302 sd = cur_ops->stall_dur() + 1;
2303 sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div;
2304 dur = sd4 + torture_random(&trs) % (sd - sd4);
2305 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
2306 stopat = rfp->rcu_fwd_startat + dur;
2307 while (time_before(jiffies, stopat) &&
2308 !shutdown_time_arrived() &&
2309 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
2310 idx = cur_ops->readlock();
2312 cur_ops->readunlock(idx);
2313 if (!fwd_progress_need_resched || need_resched())
2317 if (!time_before(jiffies, stopat) &&
2318 !shutdown_time_arrived() &&
2319 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
2321 cver = READ_ONCE(rcu_torture_current_version) - cver;
2322 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
2323 WARN_ON(!cver && gps < 2);
2324 pr_alert("%s: %d Duration %ld cver %ld gps %ld\n", __func__,
2325 rfp->rcu_fwd_id, dur, cver, gps);
2328 WRITE_ONCE(fcs.stop, 1);
2329 cur_ops->sync(); /* Wait for running CB to complete. */
2330 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id);
2331 cur_ops->cb_barrier(); /* Wait for queued callbacks. */
2335 WARN_ON(READ_ONCE(fcs.stop) != 2);
2336 destroy_rcu_head_on_stack(&fcs.rh);
2338 schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */
2339 atomic_dec(&rcu_fwd_cb_nodelay);
2342 /* Carry out call_rcu() forward-progress testing. */
2343 static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp)
2346 unsigned long flags;
2350 long n_launders_cb_snap;
2354 struct rcu_fwd_cb *rfcp;
2355 struct rcu_fwd_cb *rfcpn;
2356 unsigned long stopat;
2357 unsigned long stoppedat;
2359 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
2360 if (READ_ONCE(rcu_fwd_emergency_stop))
2361 return; /* Get out of the way quickly, no GP wait! */
2363 return; /* Can't do call_rcu() fwd prog without ->call. */
2365 /* Loop continuously posting RCU callbacks. */
2366 atomic_inc(&rcu_fwd_cb_nodelay);
2367 cur_ops->sync(); /* Later readers see above write. */
2368 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
2369 stopat = rfp->rcu_fwd_startat + MAX_FWD_CB_JIFFIES;
2371 rfp->n_launders_cb = 0; // Hoist initialization for multi-kthread
2375 for (i = 0; i < ARRAY_SIZE(rfp->n_launders_hist); i++)
2376 rfp->n_launders_hist[i].n_launders = 0;
2377 cver = READ_ONCE(rcu_torture_current_version);
2378 gps = cur_ops->get_gp_seq();
2379 rfp->rcu_launder_gp_seq_start = gps;
2380 tick_dep_set_task(current, TICK_DEP_BIT_RCU);
2381 while (time_before(jiffies, stopat) &&
2382 !shutdown_time_arrived() &&
2383 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
2384 rfcp = READ_ONCE(rfp->rcu_fwd_cb_head);
2387 rfcpn = READ_ONCE(rfcp->rfc_next);
2389 if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS &&
2390 ++n_max_gps >= MIN_FWD_CBS_LAUNDERED)
2392 rfp->rcu_fwd_cb_head = rfcpn;
2395 } else if (!cur_ops->cbflood_max || cur_ops->cbflood_max > n_max_cbs) {
2396 rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL);
2397 if (WARN_ON_ONCE(!rfcp)) {
2398 schedule_timeout_interruptible(1);
2404 rfcp->rfc_rfp = rfp;
2409 cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr);
2410 rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs);
2411 if (tick_nohz_full_enabled()) {
2412 local_irq_save(flags);
2413 rcu_momentary_dyntick_idle();
2414 local_irq_restore(flags);
2417 stoppedat = jiffies;
2418 n_launders_cb_snap = READ_ONCE(rfp->n_launders_cb);
2419 cver = READ_ONCE(rcu_torture_current_version) - cver;
2420 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
2421 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id);
2422 cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */
2423 (void)rcu_torture_fwd_prog_cbfree(rfp);
2425 if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) &&
2426 !shutdown_time_arrived()) {
2427 WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED);
2428 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",
2430 stoppedat - rfp->rcu_fwd_startat, jiffies - stoppedat,
2431 n_launders + n_max_cbs - n_launders_cb_snap,
2432 n_launders, n_launders_sa,
2433 n_max_gps, n_max_cbs, cver, gps);
2434 atomic_long_add(n_max_cbs, &rcu_fwd_max_cbs);
2435 mutex_lock(&rcu_fwd_mutex); // Serialize histograms.
2436 rcu_torture_fwd_cb_hist(rfp);
2437 mutex_unlock(&rcu_fwd_mutex);
2439 schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */
2440 tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
2441 atomic_dec(&rcu_fwd_cb_nodelay);
2446 * OOM notifier, but this only prints diagnostic information for the
2447 * current forward-progress test.
2449 static int rcutorture_oom_notify(struct notifier_block *self,
2450 unsigned long notused, void *nfreed)
2454 struct rcu_fwd *rfp;
2456 mutex_lock(&rcu_fwd_mutex);
2459 mutex_unlock(&rcu_fwd_mutex);
2462 WARN(1, "%s invoked upon OOM during forward-progress testing.\n",
2464 for (i = 0; i < fwd_progress; i++) {
2465 rcu_torture_fwd_cb_hist(&rfp[i]);
2466 rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp[i].rcu_fwd_startat)) / 2);
2468 WRITE_ONCE(rcu_fwd_emergency_stop, true);
2469 smp_mb(); /* Emergency stop before free and wait to avoid hangs. */
2471 for (i = 0; i < fwd_progress; i++)
2472 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
2473 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
2476 for (i = 0; i < fwd_progress; i++)
2477 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
2478 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
2481 for (i = 0; i < fwd_progress; i++)
2482 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
2483 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
2484 smp_mb(); /* Frees before return to avoid redoing OOM. */
2485 (*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */
2486 pr_info("%s returning after OOM processing.\n", __func__);
2487 mutex_unlock(&rcu_fwd_mutex);
2491 static struct notifier_block rcutorture_oom_nb = {
2492 .notifier_call = rcutorture_oom_notify
2495 /* Carry out grace-period forward-progress testing. */
2496 static int rcu_torture_fwd_prog(void *args)
2498 bool firsttime = true;
2500 int oldnice = task_nice(current);
2501 unsigned long oldseq = READ_ONCE(rcu_fwd_seq);
2502 struct rcu_fwd *rfp = args;
2504 int tested_tries = 0;
2506 VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started");
2507 rcu_bind_current_to_nocb();
2508 if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST))
2509 set_user_nice(current, MAX_NICE);
2511 if (!rfp->rcu_fwd_id) {
2512 schedule_timeout_interruptible(fwd_progress_holdoff * HZ);
2513 WRITE_ONCE(rcu_fwd_emergency_stop, false);
2515 max_cbs = atomic_long_xchg(&rcu_fwd_max_cbs, 0);
2516 pr_alert("%s n_max_cbs: %ld\n", __func__, max_cbs);
2519 WRITE_ONCE(rcu_fwd_seq, rcu_fwd_seq + 1);
2521 while (READ_ONCE(rcu_fwd_seq) == oldseq && !torture_must_stop())
2522 schedule_timeout_interruptible(1);
2523 oldseq = READ_ONCE(rcu_fwd_seq);
2525 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
2526 if (rcu_inkernel_boot_has_ended() && torture_num_online_cpus() > rfp->rcu_fwd_id)
2527 rcu_torture_fwd_prog_cr(rfp);
2528 if ((cur_ops->stall_dur && cur_ops->stall_dur() > 0) &&
2529 (!IS_ENABLED(CONFIG_TINY_RCU) ||
2530 (rcu_inkernel_boot_has_ended() &&
2531 torture_num_online_cpus() > rfp->rcu_fwd_id)))
2532 rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries);
2534 /* Avoid slow periods, better to test when busy. */
2535 if (stutter_wait("rcu_torture_fwd_prog"))
2536 sched_set_normal(current, oldnice);
2537 } while (!torture_must_stop());
2538 /* Short runs might not contain a valid forward-progress attempt. */
2539 if (!rfp->rcu_fwd_id) {
2540 WARN_ON(!tested && tested_tries >= 5);
2541 pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries);
2543 torture_kthread_stopping("rcu_torture_fwd_prog");
2547 /* If forward-progress checking is requested and feasible, spawn the thread. */
2548 static int __init rcu_torture_fwd_prog_init(void)
2552 struct rcu_fwd *rfp;
2555 return 0; /* Not requested, so don't do it. */
2556 if (fwd_progress >= nr_cpu_ids) {
2557 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Limiting fwd_progress to # CPUs.\n");
2558 fwd_progress = nr_cpu_ids;
2559 } else if (fwd_progress < 0) {
2560 fwd_progress = nr_cpu_ids;
2562 if ((!cur_ops->sync && !cur_ops->call) ||
2563 (!cur_ops->cbflood_max && (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0)) ||
2564 cur_ops == &rcu_busted_ops) {
2565 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test");
2569 if (stall_cpu > 0) {
2570 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing");
2572 if (IS_MODULE(CONFIG_RCU_TORTURE_TEST))
2573 return -EINVAL; /* In module, can fail back to user. */
2574 WARN_ON(1); /* Make sure rcutorture notices conflict. */
2577 if (fwd_progress_holdoff <= 0)
2578 fwd_progress_holdoff = 1;
2579 if (fwd_progress_div <= 0)
2580 fwd_progress_div = 4;
2581 rfp = kcalloc(fwd_progress, sizeof(*rfp), GFP_KERNEL);
2582 fwd_prog_tasks = kcalloc(fwd_progress, sizeof(*fwd_prog_tasks), GFP_KERNEL);
2583 if (!rfp || !fwd_prog_tasks) {
2585 kfree(fwd_prog_tasks);
2586 fwd_prog_tasks = NULL;
2590 for (i = 0; i < fwd_progress; i++) {
2591 spin_lock_init(&rfp[i].rcu_fwd_lock);
2592 rfp[i].rcu_fwd_cb_tail = &rfp[i].rcu_fwd_cb_head;
2593 rfp[i].rcu_fwd_id = i;
2595 mutex_lock(&rcu_fwd_mutex);
2597 mutex_unlock(&rcu_fwd_mutex);
2598 register_oom_notifier(&rcutorture_oom_nb);
2599 for (i = 0; i < fwd_progress; i++) {
2600 ret = torture_create_kthread(rcu_torture_fwd_prog, &rcu_fwds[i], fwd_prog_tasks[i]);
2609 static void rcu_torture_fwd_prog_cleanup(void)
2612 struct rcu_fwd *rfp;
2614 if (!rcu_fwds || !fwd_prog_tasks)
2616 for (i = 0; i < fwd_progress; i++)
2617 torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_tasks[i]);
2618 unregister_oom_notifier(&rcutorture_oom_nb);
2619 mutex_lock(&rcu_fwd_mutex);
2622 mutex_unlock(&rcu_fwd_mutex);
2624 kfree(fwd_prog_tasks);
2625 fwd_prog_tasks = NULL;
2628 /* Callback function for RCU barrier testing. */
2629 static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
2631 atomic_inc(&barrier_cbs_invoked);
2634 /* IPI handler to get callback posted on desired CPU, if online. */
2635 static void rcu_torture_barrier1cb(void *rcu_void)
2637 struct rcu_head *rhp = rcu_void;
2639 cur_ops->call(rhp, rcu_torture_barrier_cbf);
2642 /* kthread function to register callbacks used to test RCU barriers. */
2643 static int rcu_torture_barrier_cbs(void *arg)
2645 long myid = (long)arg;
2646 bool lastphase = false;
2648 struct rcu_head rcu;
2650 init_rcu_head_on_stack(&rcu);
2651 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
2652 set_user_nice(current, MAX_NICE);
2654 wait_event(barrier_cbs_wq[myid],
2656 smp_load_acquire(&barrier_phase)) != lastphase ||
2657 torture_must_stop());
2658 lastphase = newphase;
2659 if (torture_must_stop())
2662 * The above smp_load_acquire() ensures barrier_phase load
2663 * is ordered before the following ->call().
2665 if (smp_call_function_single(myid, rcu_torture_barrier1cb,
2667 // IPI failed, so use direct call from current CPU.
2668 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
2670 if (atomic_dec_and_test(&barrier_cbs_count))
2671 wake_up(&barrier_wq);
2672 } while (!torture_must_stop());
2673 if (cur_ops->cb_barrier != NULL)
2674 cur_ops->cb_barrier();
2675 destroy_rcu_head_on_stack(&rcu);
2676 torture_kthread_stopping("rcu_torture_barrier_cbs");
2680 /* kthread function to drive and coordinate RCU barrier testing. */
2681 static int rcu_torture_barrier(void *arg)
2685 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
2687 atomic_set(&barrier_cbs_invoked, 0);
2688 atomic_set(&barrier_cbs_count, n_barrier_cbs);
2689 /* Ensure barrier_phase ordered after prior assignments. */
2690 smp_store_release(&barrier_phase, !barrier_phase);
2691 for (i = 0; i < n_barrier_cbs; i++)
2692 wake_up(&barrier_cbs_wq[i]);
2693 wait_event(barrier_wq,
2694 atomic_read(&barrier_cbs_count) == 0 ||
2695 torture_must_stop());
2696 if (torture_must_stop())
2698 n_barrier_attempts++;
2699 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
2700 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
2701 n_rcu_torture_barrier_error++;
2702 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
2703 atomic_read(&barrier_cbs_invoked),
2706 // Wait manually for the remaining callbacks
2709 if (WARN_ON(i++ > HZ))
2711 schedule_timeout_interruptible(1);
2712 cur_ops->cb_barrier();
2713 } while (atomic_read(&barrier_cbs_invoked) !=
2715 !torture_must_stop());
2716 smp_mb(); // Can't trust ordering if broken.
2717 if (!torture_must_stop())
2718 pr_err("Recovered: barrier_cbs_invoked = %d\n",
2719 atomic_read(&barrier_cbs_invoked));
2721 n_barrier_successes++;
2723 schedule_timeout_interruptible(HZ / 10);
2724 } while (!torture_must_stop());
2725 torture_kthread_stopping("rcu_torture_barrier");
2729 /* Initialize RCU barrier testing. */
2730 static int rcu_torture_barrier_init(void)
2735 if (n_barrier_cbs <= 0)
2737 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
2738 pr_alert("%s" TORTURE_FLAG
2739 " Call or barrier ops missing for %s,\n",
2740 torture_type, cur_ops->name);
2741 pr_alert("%s" TORTURE_FLAG
2742 " RCU barrier testing omitted from run.\n",
2746 atomic_set(&barrier_cbs_count, 0);
2747 atomic_set(&barrier_cbs_invoked, 0);
2749 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]),
2752 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL);
2753 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
2755 for (i = 0; i < n_barrier_cbs; i++) {
2756 init_waitqueue_head(&barrier_cbs_wq[i]);
2757 ret = torture_create_kthread(rcu_torture_barrier_cbs,
2759 barrier_cbs_tasks[i]);
2763 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
2766 /* Clean up after RCU barrier testing. */
2767 static void rcu_torture_barrier_cleanup(void)
2771 torture_stop_kthread(rcu_torture_barrier, barrier_task);
2772 if (barrier_cbs_tasks != NULL) {
2773 for (i = 0; i < n_barrier_cbs; i++)
2774 torture_stop_kthread(rcu_torture_barrier_cbs,
2775 barrier_cbs_tasks[i]);
2776 kfree(barrier_cbs_tasks);
2777 barrier_cbs_tasks = NULL;
2779 if (barrier_cbs_wq != NULL) {
2780 kfree(barrier_cbs_wq);
2781 barrier_cbs_wq = NULL;
2785 static bool rcu_torture_can_boost(void)
2787 static int boost_warn_once;
2790 if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2)
2792 if (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)
2795 prio = rcu_get_gp_kthreads_prio();
2800 if (boost_warn_once == 1)
2803 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);
2804 boost_warn_once = 1;
2811 static bool read_exit_child_stop;
2812 static bool read_exit_child_stopped;
2813 static wait_queue_head_t read_exit_wq;
2815 // Child kthread which just does an rcutorture reader and exits.
2816 static int rcu_torture_read_exit_child(void *trsp_in)
2818 struct torture_random_state *trsp = trsp_in;
2820 set_user_nice(current, MAX_NICE);
2821 // Minimize time between reading and exiting.
2822 while (!kthread_should_stop())
2823 schedule_timeout_uninterruptible(1);
2824 (void)rcu_torture_one_read(trsp, -1);
2828 // Parent kthread which creates and destroys read-exit child kthreads.
2829 static int rcu_torture_read_exit(void *unused)
2832 bool errexit = false;
2834 struct task_struct *tsp;
2835 DEFINE_TORTURE_RANDOM(trs);
2837 // Allocate and initialize.
2838 set_user_nice(current, MAX_NICE);
2839 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of test");
2841 // Each pass through this loop does one read-exit episode.
2843 if (++count > read_exit_burst) {
2844 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: End of episode");
2845 rcu_barrier(); // Wait for task_struct free, avoid OOM.
2846 for (i = 0; i < read_exit_delay; i++) {
2847 schedule_timeout_uninterruptible(HZ);
2848 if (READ_ONCE(read_exit_child_stop))
2851 if (!READ_ONCE(read_exit_child_stop))
2852 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of episode");
2855 if (READ_ONCE(read_exit_child_stop))
2858 tsp = kthread_run(rcu_torture_read_exit_child,
2860 "rcu_torture_read_exit_child");
2862 TOROUT_ERRSTRING("out of memory");
2870 stutter_wait("rcu_torture_read_exit");
2871 } while (!errexit && !READ_ONCE(read_exit_child_stop));
2873 // Clean up and exit.
2874 smp_store_release(&read_exit_child_stopped, true); // After reaping.
2875 smp_mb(); // Store before wakeup.
2876 wake_up(&read_exit_wq);
2877 while (!torture_must_stop())
2878 schedule_timeout_uninterruptible(1);
2879 torture_kthread_stopping("rcu_torture_read_exit");
2883 static int rcu_torture_read_exit_init(void)
2885 if (read_exit_burst <= 0)
2887 init_waitqueue_head(&read_exit_wq);
2888 read_exit_child_stop = false;
2889 read_exit_child_stopped = false;
2890 return torture_create_kthread(rcu_torture_read_exit, NULL,
2894 static void rcu_torture_read_exit_cleanup(void)
2896 if (!read_exit_task)
2898 WRITE_ONCE(read_exit_child_stop, true);
2899 smp_mb(); // Above write before wait.
2900 wait_event(read_exit_wq, smp_load_acquire(&read_exit_child_stopped));
2901 torture_stop_kthread(rcutorture_read_exit, read_exit_task);
2904 static enum cpuhp_state rcutor_hp;
2907 rcu_torture_cleanup(void)
2911 unsigned long gp_seq = 0;
2914 if (torture_cleanup_begin()) {
2915 if (cur_ops->cb_barrier != NULL) {
2916 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier);
2917 cur_ops->cb_barrier();
2922 torture_cleanup_end();
2926 if (cur_ops->gp_kthread_dbg)
2927 cur_ops->gp_kthread_dbg();
2928 rcu_torture_read_exit_cleanup();
2929 rcu_torture_barrier_cleanup();
2930 rcu_torture_fwd_prog_cleanup();
2931 torture_stop_kthread(rcu_torture_stall, stall_task);
2932 torture_stop_kthread(rcu_torture_writer, writer_task);
2935 for (i = 0; i < nrealnocbers; i++)
2936 torture_stop_kthread(rcu_nocb_toggle, nocb_tasks[i]);
2942 for (i = 0; i < nrealreaders; i++)
2943 torture_stop_kthread(rcu_torture_reader,
2945 kfree(reader_tasks);
2946 reader_tasks = NULL;
2948 kfree(rcu_torture_reader_mbchk);
2949 rcu_torture_reader_mbchk = NULL;
2951 if (fakewriter_tasks) {
2952 for (i = 0; i < nfakewriters; i++)
2953 torture_stop_kthread(rcu_torture_fakewriter,
2954 fakewriter_tasks[i]);
2955 kfree(fakewriter_tasks);
2956 fakewriter_tasks = NULL;
2959 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq);
2960 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq);
2961 pr_alert("%s: End-test grace-period state: g%ld f%#x total-gps=%ld\n",
2962 cur_ops->name, (long)gp_seq, flags,
2963 rcutorture_seq_diff(gp_seq, start_gp_seq));
2964 torture_stop_kthread(rcu_torture_stats, stats_task);
2965 torture_stop_kthread(rcu_torture_fqs, fqs_task);
2966 if (rcu_torture_can_boost() && rcutor_hp >= 0)
2967 cpuhp_remove_state(rcutor_hp);
2970 * Wait for all RCU callbacks to fire, then do torture-type-specific
2971 * cleanup operations.
2973 if (cur_ops->cb_barrier != NULL) {
2974 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier);
2975 cur_ops->cb_barrier();
2977 if (cur_ops->cleanup != NULL)
2980 rcu_torture_mem_dump_obj();
2982 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
2984 if (err_segs_recorded) {
2985 pr_alert("Failure/close-call rcutorture reader segments:\n");
2986 if (rt_read_nsegs == 0)
2987 pr_alert("\t: No segments recorded!!!\n");
2989 for (i = 0; i < rt_read_nsegs; i++) {
2990 pr_alert("\t%d: %#x ", i, err_segs[i].rt_readstate);
2991 if (err_segs[i].rt_delay_jiffies != 0) {
2992 pr_cont("%s%ldjiffies", firsttime ? "" : "+",
2993 err_segs[i].rt_delay_jiffies);
2996 if (err_segs[i].rt_delay_ms != 0) {
2997 pr_cont("%s%ldms", firsttime ? "" : "+",
2998 err_segs[i].rt_delay_ms);
3001 if (err_segs[i].rt_delay_us != 0) {
3002 pr_cont("%s%ldus", firsttime ? "" : "+",
3003 err_segs[i].rt_delay_us);
3007 err_segs[i].rt_preempted ? "preempted" : "");
3011 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
3012 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
3013 else if (torture_onoff_failures())
3014 rcu_torture_print_module_parms(cur_ops,
3015 "End of test: RCU_HOTPLUG");
3017 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
3018 torture_cleanup_end();
3021 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
3022 static void rcu_torture_leak_cb(struct rcu_head *rhp)
3026 static void rcu_torture_err_cb(struct rcu_head *rhp)
3029 * This -might- happen due to race conditions, but is unlikely.
3030 * The scenario that leads to this happening is that the
3031 * first of the pair of duplicate callbacks is queued,
3032 * someone else starts a grace period that includes that
3033 * callback, then the second of the pair must wait for the
3034 * next grace period. Unlikely, but can happen. If it
3035 * does happen, the debug-objects subsystem won't have splatted.
3037 pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME);
3039 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
3042 * Verify that double-free causes debug-objects to complain, but only
3043 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
3044 * cannot be carried out.
3046 static void rcu_test_debug_objects(void)
3048 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
3049 struct rcu_head rh1;
3050 struct rcu_head rh2;
3051 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
3053 init_rcu_head_on_stack(&rh1);
3054 init_rcu_head_on_stack(&rh2);
3055 pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME);
3057 /* Try to queue the rh2 pair of callbacks for the same grace period. */
3058 preempt_disable(); /* Prevent preemption from interrupting test. */
3059 rcu_read_lock(); /* Make it impossible to finish a grace period. */
3060 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
3061 local_irq_disable(); /* Make it harder to start a new grace period. */
3062 call_rcu(&rh2, rcu_torture_leak_cb);
3063 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
3065 call_rcu(rhp, rcu_torture_leak_cb);
3066 call_rcu(rhp, rcu_torture_err_cb); /* Another duplicate callback. */
3072 /* Wait for them all to get done so we can safely return. */
3074 pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME);
3075 destroy_rcu_head_on_stack(&rh1);
3076 destroy_rcu_head_on_stack(&rh2);
3077 #else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
3078 pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME);
3079 #endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
3082 static void rcutorture_sync(void)
3084 static unsigned long n;
3086 if (cur_ops->sync && !(++n & 0xfff))
3091 rcu_torture_init(void)
3097 unsigned long gp_seq = 0;
3098 static struct rcu_torture_ops *torture_ops[] = {
3099 &rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops,
3100 &busted_srcud_ops, &tasks_ops, &tasks_rude_ops,
3101 &tasks_tracing_ops, &trivial_ops,
3104 if (!torture_init_begin(torture_type, verbose))
3107 /* Process args and tell the world that the torturer is on the job. */
3108 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
3109 cur_ops = torture_ops[i];
3110 if (strcmp(torture_type, cur_ops->name) == 0)
3113 if (i == ARRAY_SIZE(torture_ops)) {
3114 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
3116 pr_alert("rcu-torture types:");
3117 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
3118 pr_cont(" %s", torture_ops[i]->name);
3124 if (cur_ops->fqs == NULL && fqs_duration != 0) {
3125 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
3131 if (nreaders >= 0) {
3132 nrealreaders = nreaders;
3134 nrealreaders = num_online_cpus() - 2 - nreaders;
3135 if (nrealreaders <= 0)
3138 rcu_torture_print_module_parms(cur_ops, "Start of test");
3139 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq);
3140 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq);
3141 start_gp_seq = gp_seq;
3142 pr_alert("%s: Start-test grace-period state: g%ld f%#x\n",
3143 cur_ops->name, (long)gp_seq, flags);
3145 /* Set up the freelist. */
3147 INIT_LIST_HEAD(&rcu_torture_freelist);
3148 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
3149 rcu_tortures[i].rtort_mbtest = 0;
3150 list_add_tail(&rcu_tortures[i].rtort_free,
3151 &rcu_torture_freelist);
3154 /* Initialize the statistics so that each run gets its own numbers. */
3156 rcu_torture_current = NULL;
3157 rcu_torture_current_version = 0;
3158 atomic_set(&n_rcu_torture_alloc, 0);
3159 atomic_set(&n_rcu_torture_alloc_fail, 0);
3160 atomic_set(&n_rcu_torture_free, 0);
3161 atomic_set(&n_rcu_torture_mberror, 0);
3162 atomic_set(&n_rcu_torture_mbchk_fail, 0);
3163 atomic_set(&n_rcu_torture_mbchk_tries, 0);
3164 atomic_set(&n_rcu_torture_error, 0);
3165 n_rcu_torture_barrier_error = 0;
3166 n_rcu_torture_boost_ktrerror = 0;
3167 n_rcu_torture_boost_rterror = 0;
3168 n_rcu_torture_boost_failure = 0;
3169 n_rcu_torture_boosts = 0;
3170 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
3171 atomic_set(&rcu_torture_wcount[i], 0);
3172 for_each_possible_cpu(cpu) {
3173 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
3174 per_cpu(rcu_torture_count, cpu)[i] = 0;
3175 per_cpu(rcu_torture_batch, cpu)[i] = 0;
3178 err_segs_recorded = 0;
3181 /* Start up the kthreads. */
3183 rcu_torture_write_types();
3184 firsterr = torture_create_kthread(rcu_torture_writer, NULL,
3186 if (torture_init_error(firsterr))
3188 if (nfakewriters > 0) {
3189 fakewriter_tasks = kcalloc(nfakewriters,
3190 sizeof(fakewriter_tasks[0]),
3192 if (fakewriter_tasks == NULL) {
3193 TOROUT_ERRSTRING("out of memory");
3198 for (i = 0; i < nfakewriters; i++) {
3199 firsterr = torture_create_kthread(rcu_torture_fakewriter,
3200 NULL, fakewriter_tasks[i]);
3201 if (torture_init_error(firsterr))
3204 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
3206 rcu_torture_reader_mbchk = kcalloc(nrealreaders, sizeof(*rcu_torture_reader_mbchk),
3208 if (!reader_tasks || !rcu_torture_reader_mbchk) {
3209 TOROUT_ERRSTRING("out of memory");
3213 for (i = 0; i < nrealreaders; i++) {
3214 rcu_torture_reader_mbchk[i].rtc_chkrdr = -1;
3215 firsterr = torture_create_kthread(rcu_torture_reader, (void *)i,
3217 if (torture_init_error(firsterr))
3220 nrealnocbers = nocbs_nthreads;
3221 if (WARN_ON(nrealnocbers < 0))
3223 if (WARN_ON(nocbs_toggle < 0))
3225 if (nrealnocbers > 0) {
3226 nocb_tasks = kcalloc(nrealnocbers, sizeof(nocb_tasks[0]), GFP_KERNEL);
3227 if (nocb_tasks == NULL) {
3228 TOROUT_ERRSTRING("out of memory");
3235 for (i = 0; i < nrealnocbers; i++) {
3236 firsterr = torture_create_kthread(rcu_nocb_toggle, NULL, nocb_tasks[i]);
3237 if (torture_init_error(firsterr))
3240 if (stat_interval > 0) {
3241 firsterr = torture_create_kthread(rcu_torture_stats, NULL,
3243 if (torture_init_error(firsterr))
3246 if (test_no_idle_hz && shuffle_interval > 0) {
3247 firsterr = torture_shuffle_init(shuffle_interval * HZ);
3248 if (torture_init_error(firsterr))
3256 t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ;
3257 firsterr = torture_stutter_init(stutter * HZ, t);
3258 if (torture_init_error(firsterr))
3261 if (fqs_duration < 0)
3264 /* Create the fqs thread */
3265 firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
3267 if (torture_init_error(firsterr))
3270 if (test_boost_interval < 1)
3271 test_boost_interval = 1;
3272 if (test_boost_duration < 2)
3273 test_boost_duration = 2;
3274 if (rcu_torture_can_boost()) {
3276 boost_starttime = jiffies + test_boost_interval * HZ;
3278 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE",
3279 rcutorture_booster_init,
3280 rcutorture_booster_cleanup);
3281 rcutor_hp = firsterr;
3282 if (torture_init_error(firsterr))
3285 // Testing RCU priority boosting requires rcutorture do
3286 // some serious abuse. Counter this by running ksoftirqd
3287 // at higher priority.
3288 if (IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)) {
3289 for_each_online_cpu(cpu) {
3290 struct sched_param sp;
3291 struct task_struct *t;
3293 t = per_cpu(ksoftirqd, cpu);
3295 sp.sched_priority = 2;
3296 sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
3300 shutdown_jiffies = jiffies + shutdown_secs * HZ;
3301 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
3302 if (torture_init_error(firsterr))
3304 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval,
3306 if (torture_init_error(firsterr))
3308 firsterr = rcu_torture_stall_init();
3309 if (torture_init_error(firsterr))
3311 firsterr = rcu_torture_fwd_prog_init();
3312 if (torture_init_error(firsterr))
3314 firsterr = rcu_torture_barrier_init();
3315 if (torture_init_error(firsterr))
3317 firsterr = rcu_torture_read_exit_init();
3318 if (torture_init_error(firsterr))
3321 rcu_test_debug_objects();
3327 rcu_torture_cleanup();
3328 if (shutdown_secs) {
3329 WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST));
3335 module_init(rcu_torture_init);
3336 module_exit(rcu_torture_cleanup);