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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Read-Copy Update module-based torture test facility
4 *
5 * Copyright (C) IBM Corporation, 2005, 2006
6 *
7 * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
8 * Josh Triplett <josh@joshtriplett.org>
9 *
10 * See also: Documentation/RCU/torture.rst
11 */
12
13#define pr_fmt(fmt) fmt
14
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
50#include "rcu.h"
51
52MODULE_LICENSE("GPL");
53MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
54
55#ifndef data_race
56#define data_race(expr) \
57 ({ \
58 expr; \
59 })
60#endif
61#ifndef ASSERT_EXCLUSIVE_WRITER
62#define ASSERT_EXCLUSIVE_WRITER(var) do { } while (0)
63#endif
64#ifndef ASSERT_EXCLUSIVE_ACCESS
65#define ASSERT_EXCLUSIVE_ACCESS(var) do { } while (0)
66#endif
67
68/* Bits for ->extendables field, extendables param, and related definitions. */
69#define RCUTORTURE_RDR_SHIFT 8 /* Put SRCU index in upper bits. */
70#define RCUTORTURE_RDR_MASK ((1 << RCUTORTURE_RDR_SHIFT) - 1)
71#define RCUTORTURE_RDR_BH 0x01 /* Extend readers by disabling bh. */
72#define RCUTORTURE_RDR_IRQ 0x02 /* ... disabling interrupts. */
73#define RCUTORTURE_RDR_PREEMPT 0x04 /* ... disabling preemption. */
74#define RCUTORTURE_RDR_RBH 0x08 /* ... rcu_read_lock_bh(). */
75#define RCUTORTURE_RDR_SCHED 0x10 /* ... rcu_read_lock_sched(). */
76#define RCUTORTURE_RDR_RCU 0x20 /* ... entering another RCU reader. */
77#define RCUTORTURE_RDR_NBITS 6 /* Number of bits defined above. */
78#define RCUTORTURE_MAX_EXTEND \
79 (RCUTORTURE_RDR_BH | RCUTORTURE_RDR_IRQ | RCUTORTURE_RDR_PREEMPT | \
80 RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED)
81#define RCUTORTURE_RDR_MAX_LOOPS 0x7 /* Maximum reader extensions. */
82 /* Must be power of two minus one. */
83#define RCUTORTURE_RDR_MAX_SEGS (RCUTORTURE_RDR_MAX_LOOPS + 3)
84
85torture_param(int, extendables, RCUTORTURE_MAX_EXTEND,
86 "Extend readers by disabling bh (1), irqs (2), or preempt (4)");
87torture_param(int, fqs_duration, 0,
88 "Duration of fqs bursts (us), 0 to disable");
89torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
90torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
91torture_param(bool, fwd_progress, 1, "Test grace-period forward progress");
92torture_param(int, fwd_progress_div, 4, "Fraction of CPU stall to wait");
93torture_param(int, fwd_progress_holdoff, 60,
94 "Time between forward-progress tests (s)");
95torture_param(bool, fwd_progress_need_resched, 1,
96 "Hide cond_resched() behind need_resched()");
97torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
98torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
99torture_param(bool, gp_normal, false,
100 "Use normal (non-expedited) GP wait primitives");
101torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
102torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
103torture_param(int, n_barrier_cbs, 0,
104 "# of callbacks/kthreads for barrier testing");
105torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
106torture_param(int, nreaders, -1, "Number of RCU reader threads");
107torture_param(int, object_debug, 0,
108 "Enable debug-object double call_rcu() testing");
109torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
110torture_param(int, onoff_interval, 0,
111 "Time between CPU hotplugs (jiffies), 0=disable");
112torture_param(int, read_exit_delay, 13,
113 "Delay between read-then-exit episodes (s)");
114torture_param(int, read_exit_burst, 16,
115 "# of read-then-exit bursts per episode, zero to disable");
116torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
117torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
118torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
119torture_param(int, stall_cpu_holdoff, 10,
120 "Time to wait before starting stall (s).");
121torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling.");
122torture_param(int, stall_cpu_block, 0, "Sleep while stalling.");
123torture_param(int, stall_gp_kthread, 0,
124 "Grace-period kthread stall duration (s).");
125torture_param(int, stat_interval, 60,
126 "Number of seconds between stats printk()s");
127torture_param(int, stutter, 5, "Number of seconds to run/halt test");
128torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
129torture_param(int, test_boost_duration, 4,
130 "Duration of each boost test, seconds.");
131torture_param(int, test_boost_interval, 7,
132 "Interval between boost tests, seconds.");
133torture_param(bool, test_no_idle_hz, true,
134 "Test support for tickless idle CPUs");
135torture_param(int, verbose, 1,
136 "Enable verbose debugging printk()s");
137
138static char *torture_type = "rcu";
139module_param(torture_type, charp, 0444);
140MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, srcu, ...)");
141
142static int nrealreaders;
143static struct task_struct *writer_task;
144static struct task_struct **fakewriter_tasks;
145static struct task_struct **reader_tasks;
146static struct task_struct *stats_task;
147static struct task_struct *fqs_task;
148static struct task_struct *boost_tasks[NR_CPUS];
149static struct task_struct *stall_task;
150static struct task_struct *fwd_prog_task;
151static struct task_struct **barrier_cbs_tasks;
152static struct task_struct *barrier_task;
153static struct task_struct *read_exit_task;
154
155#define RCU_TORTURE_PIPE_LEN 10
156
157struct rcu_torture {
158 struct rcu_head rtort_rcu;
159 int rtort_pipe_count;
160 struct list_head rtort_free;
161 int rtort_mbtest;
162};
163
164static LIST_HEAD(rcu_torture_freelist);
165static struct rcu_torture __rcu *rcu_torture_current;
166static unsigned long rcu_torture_current_version;
167static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
168static DEFINE_SPINLOCK(rcu_torture_lock);
169static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count);
170static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch);
171static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
172static atomic_t n_rcu_torture_alloc;
173static atomic_t n_rcu_torture_alloc_fail;
174static atomic_t n_rcu_torture_free;
175static atomic_t n_rcu_torture_mberror;
176static atomic_t n_rcu_torture_error;
177static long n_rcu_torture_barrier_error;
178static long n_rcu_torture_boost_ktrerror;
179static long n_rcu_torture_boost_rterror;
180static long n_rcu_torture_boost_failure;
181static long n_rcu_torture_boosts;
182static atomic_long_t n_rcu_torture_timers;
183static long n_barrier_attempts;
184static long n_barrier_successes; /* did rcu_barrier test succeed? */
185static unsigned long n_read_exits;
186static struct list_head rcu_torture_removed;
187static unsigned long shutdown_jiffies;
188
189static int rcu_torture_writer_state;
190#define RTWS_FIXED_DELAY 0
191#define RTWS_DELAY 1
192#define RTWS_REPLACE 2
193#define RTWS_DEF_FREE 3
194#define RTWS_EXP_SYNC 4
195#define RTWS_COND_GET 5
196#define RTWS_COND_SYNC 6
197#define RTWS_SYNC 7
198#define RTWS_STUTTER 8
199#define RTWS_STOPPING 9
200static const char * const rcu_torture_writer_state_names[] = {
201 "RTWS_FIXED_DELAY",
202 "RTWS_DELAY",
203 "RTWS_REPLACE",
204 "RTWS_DEF_FREE",
205 "RTWS_EXP_SYNC",
206 "RTWS_COND_GET",
207 "RTWS_COND_SYNC",
208 "RTWS_SYNC",
209 "RTWS_STUTTER",
210 "RTWS_STOPPING",
211};
212
213/* Record reader segment types and duration for first failing read. */
214struct rt_read_seg {
215 int rt_readstate;
216 unsigned long rt_delay_jiffies;
217 unsigned long rt_delay_ms;
218 unsigned long rt_delay_us;
219 bool rt_preempted;
220};
221static int err_segs_recorded;
222static struct rt_read_seg err_segs[RCUTORTURE_RDR_MAX_SEGS];
223static int rt_read_nsegs;
224
225static const char *rcu_torture_writer_state_getname(void)
226{
227 unsigned int i = READ_ONCE(rcu_torture_writer_state);
228
229 if (i >= ARRAY_SIZE(rcu_torture_writer_state_names))
230 return "???";
231 return rcu_torture_writer_state_names[i];
232}
233
234#if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
235#define rcu_can_boost() 1
236#else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
237#define rcu_can_boost() 0
238#endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
239
240#ifdef CONFIG_RCU_TRACE
241static u64 notrace rcu_trace_clock_local(void)
242{
243 u64 ts = trace_clock_local();
244
245 (void)do_div(ts, NSEC_PER_USEC);
246 return ts;
247}
248#else /* #ifdef CONFIG_RCU_TRACE */
249static u64 notrace rcu_trace_clock_local(void)
250{
251 return 0ULL;
252}
253#endif /* #else #ifdef CONFIG_RCU_TRACE */
254
255/*
256 * Stop aggressive CPU-hog tests a bit before the end of the test in order
257 * to avoid interfering with test shutdown.
258 */
259static bool shutdown_time_arrived(void)
260{
261 return shutdown_secs && time_after(jiffies, shutdown_jiffies - 30 * HZ);
262}
263
264static unsigned long boost_starttime; /* jiffies of next boost test start. */
265static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
266 /* and boost task create/destroy. */
267static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
268static bool barrier_phase; /* Test phase. */
269static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
270static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
271static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
272
273static bool rcu_fwd_cb_nodelay; /* Short rcu_torture_delay() delays. */
274
275/*
276 * Allocate an element from the rcu_tortures pool.
277 */
278static struct rcu_torture *
279rcu_torture_alloc(void)
280{
281 struct list_head *p;
282
283 spin_lock_bh(&rcu_torture_lock);
284 if (list_empty(&rcu_torture_freelist)) {
285 atomic_inc(&n_rcu_torture_alloc_fail);
286 spin_unlock_bh(&rcu_torture_lock);
287 return NULL;
288 }
289 atomic_inc(&n_rcu_torture_alloc);
290 p = rcu_torture_freelist.next;
291 list_del_init(p);
292 spin_unlock_bh(&rcu_torture_lock);
293 return container_of(p, struct rcu_torture, rtort_free);
294}
295
296/*
297 * Free an element to the rcu_tortures pool.
298 */
299static void
300rcu_torture_free(struct rcu_torture *p)
301{
302 atomic_inc(&n_rcu_torture_free);
303 spin_lock_bh(&rcu_torture_lock);
304 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
305 spin_unlock_bh(&rcu_torture_lock);
306}
307
308/*
309 * Operations vector for selecting different types of tests.
310 */
311
312struct rcu_torture_ops {
313 int ttype;
314 void (*init)(void);
315 void (*cleanup)(void);
316 int (*readlock)(void);
317 void (*read_delay)(struct torture_random_state *rrsp,
318 struct rt_read_seg *rtrsp);
319 void (*readunlock)(int idx);
320 unsigned long (*get_gp_seq)(void);
321 unsigned long (*gp_diff)(unsigned long new, unsigned long old);
322 void (*deferred_free)(struct rcu_torture *p);
323 void (*sync)(void);
324 void (*exp_sync)(void);
325 unsigned long (*get_state)(void);
326 void (*cond_sync)(unsigned long oldstate);
327 call_rcu_func_t call;
328 void (*cb_barrier)(void);
329 void (*fqs)(void);
330 void (*stats)(void);
331 int (*stall_dur)(void);
332 int irq_capable;
333 int can_boost;
334 int extendables;
335 int slow_gps;
336 const char *name;
337};
338
339static struct rcu_torture_ops *cur_ops;
340
341/*
342 * Definitions for rcu torture testing.
343 */
344
345static int rcu_torture_read_lock(void) __acquires(RCU)
346{
347 rcu_read_lock();
348 return 0;
349}
350
351static void
352rcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
353{
354 unsigned long started;
355 unsigned long completed;
356 const unsigned long shortdelay_us = 200;
357 unsigned long longdelay_ms = 300;
358 unsigned long long ts;
359
360 /* We want a short delay sometimes to make a reader delay the grace
361 * period, and we want a long delay occasionally to trigger
362 * force_quiescent_state. */
363
364 if (!READ_ONCE(rcu_fwd_cb_nodelay) &&
365 !(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) {
366 started = cur_ops->get_gp_seq();
367 ts = rcu_trace_clock_local();
368 if (preempt_count() & (SOFTIRQ_MASK | HARDIRQ_MASK))
369 longdelay_ms = 5; /* Avoid triggering BH limits. */
370 mdelay(longdelay_ms);
371 rtrsp->rt_delay_ms = longdelay_ms;
372 completed = cur_ops->get_gp_seq();
373 do_trace_rcu_torture_read(cur_ops->name, NULL, ts,
374 started, completed);
375 }
376 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) {
377 udelay(shortdelay_us);
378 rtrsp->rt_delay_us = shortdelay_us;
379 }
380 if (!preempt_count() &&
381 !(torture_random(rrsp) % (nrealreaders * 500))) {
382 torture_preempt_schedule(); /* QS only if preemptible. */
383 rtrsp->rt_preempted = true;
384 }
385}
386
387static void rcu_torture_read_unlock(int idx) __releases(RCU)
388{
389 rcu_read_unlock();
390}
391
392/*
393 * Update callback in the pipe. This should be invoked after a grace period.
394 */
395static bool
396rcu_torture_pipe_update_one(struct rcu_torture *rp)
397{
398 int i;
399
400 i = READ_ONCE(rp->rtort_pipe_count);
401 if (i > RCU_TORTURE_PIPE_LEN)
402 i = RCU_TORTURE_PIPE_LEN;
403 atomic_inc(&rcu_torture_wcount[i]);
404 WRITE_ONCE(rp->rtort_pipe_count, i + 1);
405 if (rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
406 rp->rtort_mbtest = 0;
407 return true;
408 }
409 return false;
410}
411
412/*
413 * Update all callbacks in the pipe. Suitable for synchronous grace-period
414 * primitives.
415 */
416static void
417rcu_torture_pipe_update(struct rcu_torture *old_rp)
418{
419 struct rcu_torture *rp;
420 struct rcu_torture *rp1;
421
422 if (old_rp)
423 list_add(&old_rp->rtort_free, &rcu_torture_removed);
424 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
425 if (rcu_torture_pipe_update_one(rp)) {
426 list_del(&rp->rtort_free);
427 rcu_torture_free(rp);
428 }
429 }
430}
431
432static void
433rcu_torture_cb(struct rcu_head *p)
434{
435 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
436
437 if (torture_must_stop_irq()) {
438 /* Test is ending, just drop callbacks on the floor. */
439 /* The next initialization will pick up the pieces. */
440 return;
441 }
442 if (rcu_torture_pipe_update_one(rp))
443 rcu_torture_free(rp);
444 else
445 cur_ops->deferred_free(rp);
446}
447
448static unsigned long rcu_no_completed(void)
449{
450 return 0;
451}
452
453static void rcu_torture_deferred_free(struct rcu_torture *p)
454{
455 call_rcu(&p->rtort_rcu, rcu_torture_cb);
456}
457
458static void rcu_sync_torture_init(void)
459{
460 INIT_LIST_HEAD(&rcu_torture_removed);
461}
462
463static struct rcu_torture_ops rcu_ops = {
464 .ttype = RCU_FLAVOR,
465 .init = rcu_sync_torture_init,
466 .readlock = rcu_torture_read_lock,
467 .read_delay = rcu_read_delay,
468 .readunlock = rcu_torture_read_unlock,
469 .get_gp_seq = rcu_get_gp_seq,
470 .gp_diff = rcu_seq_diff,
471 .deferred_free = rcu_torture_deferred_free,
472 .sync = synchronize_rcu,
473 .exp_sync = synchronize_rcu_expedited,
474 .get_state = get_state_synchronize_rcu,
475 .cond_sync = cond_synchronize_rcu,
476 .call = call_rcu,
477 .cb_barrier = rcu_barrier,
478 .fqs = rcu_force_quiescent_state,
479 .stats = NULL,
480 .stall_dur = rcu_jiffies_till_stall_check,
481 .irq_capable = 1,
482 .can_boost = rcu_can_boost(),
483 .extendables = RCUTORTURE_MAX_EXTEND,
484 .name = "rcu"
485};
486
487/*
488 * Don't even think about trying any of these in real life!!!
489 * The names includes "busted", and they really means it!
490 * The only purpose of these functions is to provide a buggy RCU
491 * implementation to make sure that rcutorture correctly emits
492 * buggy-RCU error messages.
493 */
494static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
495{
496 /* This is a deliberate bug for testing purposes only! */
497 rcu_torture_cb(&p->rtort_rcu);
498}
499
500static void synchronize_rcu_busted(void)
501{
502 /* This is a deliberate bug for testing purposes only! */
503}
504
505static void
506call_rcu_busted(struct rcu_head *head, rcu_callback_t func)
507{
508 /* This is a deliberate bug for testing purposes only! */
509 func(head);
510}
511
512static struct rcu_torture_ops rcu_busted_ops = {
513 .ttype = INVALID_RCU_FLAVOR,
514 .init = rcu_sync_torture_init,
515 .readlock = rcu_torture_read_lock,
516 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
517 .readunlock = rcu_torture_read_unlock,
518 .get_gp_seq = rcu_no_completed,
519 .deferred_free = rcu_busted_torture_deferred_free,
520 .sync = synchronize_rcu_busted,
521 .exp_sync = synchronize_rcu_busted,
522 .call = call_rcu_busted,
523 .cb_barrier = NULL,
524 .fqs = NULL,
525 .stats = NULL,
526 .irq_capable = 1,
527 .name = "busted"
528};
529
530/*
531 * Definitions for srcu torture testing.
532 */
533
534DEFINE_STATIC_SRCU(srcu_ctl);
535static struct srcu_struct srcu_ctld;
536static struct srcu_struct *srcu_ctlp = &srcu_ctl;
537
538static int srcu_torture_read_lock(void) __acquires(srcu_ctlp)
539{
540 return srcu_read_lock(srcu_ctlp);
541}
542
543static void
544srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
545{
546 long delay;
547 const long uspertick = 1000000 / HZ;
548 const long longdelay = 10;
549
550 /* We want there to be long-running readers, but not all the time. */
551
552 delay = torture_random(rrsp) %
553 (nrealreaders * 2 * longdelay * uspertick);
554 if (!delay && in_task()) {
555 schedule_timeout_interruptible(longdelay);
556 rtrsp->rt_delay_jiffies = longdelay;
557 } else {
558 rcu_read_delay(rrsp, rtrsp);
559 }
560}
561
562static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp)
563{
564 srcu_read_unlock(srcu_ctlp, idx);
565}
566
567static unsigned long srcu_torture_completed(void)
568{
569 return srcu_batches_completed(srcu_ctlp);
570}
571
572static void srcu_torture_deferred_free(struct rcu_torture *rp)
573{
574 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
575}
576
577static void srcu_torture_synchronize(void)
578{
579 synchronize_srcu(srcu_ctlp);
580}
581
582static void srcu_torture_call(struct rcu_head *head,
583 rcu_callback_t func)
584{
585 call_srcu(srcu_ctlp, head, func);
586}
587
588static void srcu_torture_barrier(void)
589{
590 srcu_barrier(srcu_ctlp);
591}
592
593static void srcu_torture_stats(void)
594{
595 srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG);
596}
597
598static void srcu_torture_synchronize_expedited(void)
599{
600 synchronize_srcu_expedited(srcu_ctlp);
601}
602
603static struct rcu_torture_ops srcu_ops = {
604 .ttype = SRCU_FLAVOR,
605 .init = rcu_sync_torture_init,
606 .readlock = srcu_torture_read_lock,
607 .read_delay = srcu_read_delay,
608 .readunlock = srcu_torture_read_unlock,
609 .get_gp_seq = srcu_torture_completed,
610 .deferred_free = srcu_torture_deferred_free,
611 .sync = srcu_torture_synchronize,
612 .exp_sync = srcu_torture_synchronize_expedited,
613 .call = srcu_torture_call,
614 .cb_barrier = srcu_torture_barrier,
615 .stats = srcu_torture_stats,
616 .irq_capable = 1,
617 .name = "srcu"
618};
619
620static void srcu_torture_init(void)
621{
622 rcu_sync_torture_init();
623 WARN_ON(init_srcu_struct(&srcu_ctld));
624 srcu_ctlp = &srcu_ctld;
625}
626
627static void srcu_torture_cleanup(void)
628{
629 cleanup_srcu_struct(&srcu_ctld);
630 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
631}
632
633/* As above, but dynamically allocated. */
634static struct rcu_torture_ops srcud_ops = {
635 .ttype = SRCU_FLAVOR,
636 .init = srcu_torture_init,
637 .cleanup = srcu_torture_cleanup,
638 .readlock = srcu_torture_read_lock,
639 .read_delay = srcu_read_delay,
640 .readunlock = srcu_torture_read_unlock,
641 .get_gp_seq = srcu_torture_completed,
642 .deferred_free = srcu_torture_deferred_free,
643 .sync = srcu_torture_synchronize,
644 .exp_sync = srcu_torture_synchronize_expedited,
645 .call = srcu_torture_call,
646 .cb_barrier = srcu_torture_barrier,
647 .stats = srcu_torture_stats,
648 .irq_capable = 1,
649 .name = "srcud"
650};
651
652/* As above, but broken due to inappropriate reader extension. */
653static struct rcu_torture_ops busted_srcud_ops = {
654 .ttype = SRCU_FLAVOR,
655 .init = srcu_torture_init,
656 .cleanup = srcu_torture_cleanup,
657 .readlock = srcu_torture_read_lock,
658 .read_delay = rcu_read_delay,
659 .readunlock = srcu_torture_read_unlock,
660 .get_gp_seq = srcu_torture_completed,
661 .deferred_free = srcu_torture_deferred_free,
662 .sync = srcu_torture_synchronize,
663 .exp_sync = srcu_torture_synchronize_expedited,
664 .call = srcu_torture_call,
665 .cb_barrier = srcu_torture_barrier,
666 .stats = srcu_torture_stats,
667 .irq_capable = 1,
668 .extendables = RCUTORTURE_MAX_EXTEND,
669 .name = "busted_srcud"
670};
671
672/*
673 * Definitions for RCU-tasks torture testing.
674 */
675
676static int tasks_torture_read_lock(void)
677{
678 return 0;
679}
680
681static void tasks_torture_read_unlock(int idx)
682{
683}
684
685static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
686{
687 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
688}
689
690static void synchronize_rcu_mult_test(void)
691{
692 synchronize_rcu_mult(call_rcu_tasks, call_rcu);
693}
694
695static struct rcu_torture_ops tasks_ops = {
696 .ttype = RCU_TASKS_FLAVOR,
697 .init = rcu_sync_torture_init,
698 .readlock = tasks_torture_read_lock,
699 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
700 .readunlock = tasks_torture_read_unlock,
701 .get_gp_seq = rcu_no_completed,
702 .deferred_free = rcu_tasks_torture_deferred_free,
703 .sync = synchronize_rcu_tasks,
704 .exp_sync = synchronize_rcu_mult_test,
705 .call = call_rcu_tasks,
706 .cb_barrier = rcu_barrier_tasks,
707 .fqs = NULL,
708 .stats = NULL,
709 .irq_capable = 1,
710 .slow_gps = 1,
711 .name = "tasks"
712};
713
714/*
715 * Definitions for trivial CONFIG_PREEMPT=n-only torture testing.
716 * This implementation does not necessarily work well with CPU hotplug.
717 */
718
719static void synchronize_rcu_trivial(void)
720{
721 int cpu;
722
723 for_each_online_cpu(cpu) {
724 rcutorture_sched_setaffinity(current->pid, cpumask_of(cpu));
725 WARN_ON_ONCE(raw_smp_processor_id() != cpu);
726 }
727}
728
729static int rcu_torture_read_lock_trivial(void) __acquires(RCU)
730{
731 preempt_disable();
732 return 0;
733}
734
735static void rcu_torture_read_unlock_trivial(int idx) __releases(RCU)
736{
737 preempt_enable();
738}
739
740static struct rcu_torture_ops trivial_ops = {
741 .ttype = RCU_TRIVIAL_FLAVOR,
742 .init = rcu_sync_torture_init,
743 .readlock = rcu_torture_read_lock_trivial,
744 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
745 .readunlock = rcu_torture_read_unlock_trivial,
746 .get_gp_seq = rcu_no_completed,
747 .sync = synchronize_rcu_trivial,
748 .exp_sync = synchronize_rcu_trivial,
749 .fqs = NULL,
750 .stats = NULL,
751 .irq_capable = 1,
752 .name = "trivial"
753};
754
755/*
756 * Definitions for rude RCU-tasks torture testing.
757 */
758
759static void rcu_tasks_rude_torture_deferred_free(struct rcu_torture *p)
760{
761 call_rcu_tasks_rude(&p->rtort_rcu, rcu_torture_cb);
762}
763
764static struct rcu_torture_ops tasks_rude_ops = {
765 .ttype = RCU_TASKS_RUDE_FLAVOR,
766 .init = rcu_sync_torture_init,
767 .readlock = rcu_torture_read_lock_trivial,
768 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
769 .readunlock = rcu_torture_read_unlock_trivial,
770 .get_gp_seq = rcu_no_completed,
771 .deferred_free = rcu_tasks_rude_torture_deferred_free,
772 .sync = synchronize_rcu_tasks_rude,
773 .exp_sync = synchronize_rcu_tasks_rude,
774 .call = call_rcu_tasks_rude,
775 .cb_barrier = rcu_barrier_tasks_rude,
776 .fqs = NULL,
777 .stats = NULL,
778 .irq_capable = 1,
779 .name = "tasks-rude"
780};
781
782/*
783 * Definitions for tracing RCU-tasks torture testing.
784 */
785
786static int tasks_tracing_torture_read_lock(void)
787{
788 rcu_read_lock_trace();
789 return 0;
790}
791
792static void tasks_tracing_torture_read_unlock(int idx)
793{
794 rcu_read_unlock_trace();
795}
796
797static void rcu_tasks_tracing_torture_deferred_free(struct rcu_torture *p)
798{
799 call_rcu_tasks_trace(&p->rtort_rcu, rcu_torture_cb);
800}
801
802static struct rcu_torture_ops tasks_tracing_ops = {
803 .ttype = RCU_TASKS_TRACING_FLAVOR,
804 .init = rcu_sync_torture_init,
805 .readlock = tasks_tracing_torture_read_lock,
806 .read_delay = srcu_read_delay, /* just reuse srcu's version. */
807 .readunlock = tasks_tracing_torture_read_unlock,
808 .get_gp_seq = rcu_no_completed,
809 .deferred_free = rcu_tasks_tracing_torture_deferred_free,
810 .sync = synchronize_rcu_tasks_trace,
811 .exp_sync = synchronize_rcu_tasks_trace,
812 .call = call_rcu_tasks_trace,
813 .cb_barrier = rcu_barrier_tasks_trace,
814 .fqs = NULL,
815 .stats = NULL,
816 .irq_capable = 1,
817 .slow_gps = 1,
818 .name = "tasks-tracing"
819};
820
821static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old)
822{
823 if (!cur_ops->gp_diff)
824 return new - old;
825 return cur_ops->gp_diff(new, old);
826}
827
828static bool __maybe_unused torturing_tasks(void)
829{
830 return cur_ops == &tasks_ops || cur_ops == &tasks_rude_ops;
831}
832
833/*
834 * RCU torture priority-boost testing. Runs one real-time thread per
835 * CPU for moderate bursts, repeatedly registering RCU callbacks and
836 * spinning waiting for them to be invoked. If a given callback takes
837 * too long to be invoked, we assume that priority inversion has occurred.
838 */
839
840struct rcu_boost_inflight {
841 struct rcu_head rcu;
842 int inflight;
843};
844
845static void rcu_torture_boost_cb(struct rcu_head *head)
846{
847 struct rcu_boost_inflight *rbip =
848 container_of(head, struct rcu_boost_inflight, rcu);
849
850 /* Ensure RCU-core accesses precede clearing ->inflight */
851 smp_store_release(&rbip->inflight, 0);
852}
853
854static int old_rt_runtime = -1;
855
856static void rcu_torture_disable_rt_throttle(void)
857{
858 /*
859 * Disable RT throttling so that rcutorture's boost threads don't get
860 * throttled. Only possible if rcutorture is built-in otherwise the
861 * user should manually do this by setting the sched_rt_period_us and
862 * sched_rt_runtime sysctls.
863 */
864 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime != -1)
865 return;
866
867 old_rt_runtime = sysctl_sched_rt_runtime;
868 sysctl_sched_rt_runtime = -1;
869}
870
871static void rcu_torture_enable_rt_throttle(void)
872{
873 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime == -1)
874 return;
875
876 sysctl_sched_rt_runtime = old_rt_runtime;
877 old_rt_runtime = -1;
878}
879
880static bool rcu_torture_boost_failed(unsigned long start, unsigned long end)
881{
882 if (end - start > test_boost_duration * HZ - HZ / 2) {
883 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
884 n_rcu_torture_boost_failure++;
885
886 return true; /* failed */
887 }
888
889 return false; /* passed */
890}
891
892static int rcu_torture_boost(void *arg)
893{
894 unsigned long call_rcu_time;
895 unsigned long endtime;
896 unsigned long oldstarttime;
897 struct rcu_boost_inflight rbi = { .inflight = 0 };
898
899 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
900
901 /* Set real-time priority. */
902 sched_set_fifo_low(current);
903
904 init_rcu_head_on_stack(&rbi.rcu);
905 /* Each pass through the following loop does one boost-test cycle. */
906 do {
907 /* Track if the test failed already in this test interval? */
908 bool failed = false;
909
910 /* Increment n_rcu_torture_boosts once per boost-test */
911 while (!kthread_should_stop()) {
912 if (mutex_trylock(&boost_mutex)) {
913 n_rcu_torture_boosts++;
914 mutex_unlock(&boost_mutex);
915 break;
916 }
917 schedule_timeout_uninterruptible(1);
918 }
919 if (kthread_should_stop())
920 goto checkwait;
921
922 /* Wait for the next test interval. */
923 oldstarttime = boost_starttime;
924 while (time_before(jiffies, oldstarttime)) {
925 schedule_timeout_interruptible(oldstarttime - jiffies);
926 stutter_wait("rcu_torture_boost");
927 if (torture_must_stop())
928 goto checkwait;
929 }
930
931 /* Do one boost-test interval. */
932 endtime = oldstarttime + test_boost_duration * HZ;
933 call_rcu_time = jiffies;
934 while (time_before(jiffies, endtime)) {
935 /* If we don't have a callback in flight, post one. */
936 if (!smp_load_acquire(&rbi.inflight)) {
937 /* RCU core before ->inflight = 1. */
938 smp_store_release(&rbi.inflight, 1);
939 call_rcu(&rbi.rcu, rcu_torture_boost_cb);
940 /* Check if the boost test failed */
941 failed = failed ||
942 rcu_torture_boost_failed(call_rcu_time,
943 jiffies);
944 call_rcu_time = jiffies;
945 }
946 stutter_wait("rcu_torture_boost");
947 if (torture_must_stop())
948 goto checkwait;
949 }
950
951 /*
952 * If boost never happened, then inflight will always be 1, in
953 * this case the boost check would never happen in the above
954 * loop so do another one here.
955 */
956 if (!failed && smp_load_acquire(&rbi.inflight))
957 rcu_torture_boost_failed(call_rcu_time, jiffies);
958
959 /*
960 * Set the start time of the next test interval.
961 * Yes, this is vulnerable to long delays, but such
962 * delays simply cause a false negative for the next
963 * interval. Besides, we are running at RT priority,
964 * so delays should be relatively rare.
965 */
966 while (oldstarttime == boost_starttime &&
967 !kthread_should_stop()) {
968 if (mutex_trylock(&boost_mutex)) {
969 boost_starttime = jiffies +
970 test_boost_interval * HZ;
971 mutex_unlock(&boost_mutex);
972 break;
973 }
974 schedule_timeout_uninterruptible(1);
975 }
976
977 /* Go do the stutter. */
978checkwait: stutter_wait("rcu_torture_boost");
979 } while (!torture_must_stop());
980
981 /* Clean up and exit. */
982 while (!kthread_should_stop() || smp_load_acquire(&rbi.inflight)) {
983 torture_shutdown_absorb("rcu_torture_boost");
984 schedule_timeout_uninterruptible(1);
985 }
986 destroy_rcu_head_on_stack(&rbi.rcu);
987 torture_kthread_stopping("rcu_torture_boost");
988 return 0;
989}
990
991/*
992 * RCU torture force-quiescent-state kthread. Repeatedly induces
993 * bursts of calls to force_quiescent_state(), increasing the probability
994 * of occurrence of some important types of race conditions.
995 */
996static int
997rcu_torture_fqs(void *arg)
998{
999 unsigned long fqs_resume_time;
1000 int fqs_burst_remaining;
1001
1002 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
1003 do {
1004 fqs_resume_time = jiffies + fqs_stutter * HZ;
1005 while (time_before(jiffies, fqs_resume_time) &&
1006 !kthread_should_stop()) {
1007 schedule_timeout_interruptible(1);
1008 }
1009 fqs_burst_remaining = fqs_duration;
1010 while (fqs_burst_remaining > 0 &&
1011 !kthread_should_stop()) {
1012 cur_ops->fqs();
1013 udelay(fqs_holdoff);
1014 fqs_burst_remaining -= fqs_holdoff;
1015 }
1016 stutter_wait("rcu_torture_fqs");
1017 } while (!torture_must_stop());
1018 torture_kthread_stopping("rcu_torture_fqs");
1019 return 0;
1020}
1021
1022/*
1023 * RCU torture writer kthread. Repeatedly substitutes a new structure
1024 * for that pointed to by rcu_torture_current, freeing the old structure
1025 * after a series of grace periods (the "pipeline").
1026 */
1027static int
1028rcu_torture_writer(void *arg)
1029{
1030 bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
1031 int expediting = 0;
1032 unsigned long gp_snap;
1033 bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal;
1034 bool gp_sync1 = gp_sync;
1035 int i;
1036 struct rcu_torture *rp;
1037 struct rcu_torture *old_rp;
1038 static DEFINE_TORTURE_RANDOM(rand);
1039 int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC,
1040 RTWS_COND_GET, RTWS_SYNC };
1041 int nsynctypes = 0;
1042
1043 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
1044 if (!can_expedite)
1045 pr_alert("%s" TORTURE_FLAG
1046 " GP expediting controlled from boot/sysfs for %s.\n",
1047 torture_type, cur_ops->name);
1048
1049 /* Initialize synctype[] array. If none set, take default. */
1050 if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync1)
1051 gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true;
1052 if (gp_cond1 && cur_ops->get_state && cur_ops->cond_sync) {
1053 synctype[nsynctypes++] = RTWS_COND_GET;
1054 pr_info("%s: Testing conditional GPs.\n", __func__);
1055 } else if (gp_cond && (!cur_ops->get_state || !cur_ops->cond_sync)) {
1056 pr_alert("%s: gp_cond without primitives.\n", __func__);
1057 }
1058 if (gp_exp1 && cur_ops->exp_sync) {
1059 synctype[nsynctypes++] = RTWS_EXP_SYNC;
1060 pr_info("%s: Testing expedited GPs.\n", __func__);
1061 } else if (gp_exp && !cur_ops->exp_sync) {
1062 pr_alert("%s: gp_exp without primitives.\n", __func__);
1063 }
1064 if (gp_normal1 && cur_ops->deferred_free) {
1065 synctype[nsynctypes++] = RTWS_DEF_FREE;
1066 pr_info("%s: Testing asynchronous GPs.\n", __func__);
1067 } else if (gp_normal && !cur_ops->deferred_free) {
1068 pr_alert("%s: gp_normal without primitives.\n", __func__);
1069 }
1070 if (gp_sync1 && cur_ops->sync) {
1071 synctype[nsynctypes++] = RTWS_SYNC;
1072 pr_info("%s: Testing normal GPs.\n", __func__);
1073 } else if (gp_sync && !cur_ops->sync) {
1074 pr_alert("%s: gp_sync without primitives.\n", __func__);
1075 }
1076 if (WARN_ONCE(nsynctypes == 0,
1077 "rcu_torture_writer: No update-side primitives.\n")) {
1078 /*
1079 * No updates primitives, so don't try updating.
1080 * The resulting test won't be testing much, hence the
1081 * above WARN_ONCE().
1082 */
1083 rcu_torture_writer_state = RTWS_STOPPING;
1084 torture_kthread_stopping("rcu_torture_writer");
1085 }
1086
1087 do {
1088 rcu_torture_writer_state = RTWS_FIXED_DELAY;
1089 schedule_timeout_uninterruptible(1);
1090 rp = rcu_torture_alloc();
1091 if (rp == NULL)
1092 continue;
1093 rp->rtort_pipe_count = 0;
1094 rcu_torture_writer_state = RTWS_DELAY;
1095 udelay(torture_random(&rand) & 0x3ff);
1096 rcu_torture_writer_state = RTWS_REPLACE;
1097 old_rp = rcu_dereference_check(rcu_torture_current,
1098 current == writer_task);
1099 rp->rtort_mbtest = 1;
1100 rcu_assign_pointer(rcu_torture_current, rp);
1101 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
1102 if (old_rp) {
1103 i = old_rp->rtort_pipe_count;
1104 if (i > RCU_TORTURE_PIPE_LEN)
1105 i = RCU_TORTURE_PIPE_LEN;
1106 atomic_inc(&rcu_torture_wcount[i]);
1107 WRITE_ONCE(old_rp->rtort_pipe_count,
1108 old_rp->rtort_pipe_count + 1);
1109 switch (synctype[torture_random(&rand) % nsynctypes]) {
1110 case RTWS_DEF_FREE:
1111 rcu_torture_writer_state = RTWS_DEF_FREE;
1112 cur_ops->deferred_free(old_rp);
1113 break;
1114 case RTWS_EXP_SYNC:
1115 rcu_torture_writer_state = RTWS_EXP_SYNC;
1116 cur_ops->exp_sync();
1117 rcu_torture_pipe_update(old_rp);
1118 break;
1119 case RTWS_COND_GET:
1120 rcu_torture_writer_state = RTWS_COND_GET;
1121 gp_snap = cur_ops->get_state();
1122 i = torture_random(&rand) % 16;
1123 if (i != 0)
1124 schedule_timeout_interruptible(i);
1125 udelay(torture_random(&rand) % 1000);
1126 rcu_torture_writer_state = RTWS_COND_SYNC;
1127 cur_ops->cond_sync(gp_snap);
1128 rcu_torture_pipe_update(old_rp);
1129 break;
1130 case RTWS_SYNC:
1131 rcu_torture_writer_state = RTWS_SYNC;
1132 cur_ops->sync();
1133 rcu_torture_pipe_update(old_rp);
1134 break;
1135 default:
1136 WARN_ON_ONCE(1);
1137 break;
1138 }
1139 }
1140 WRITE_ONCE(rcu_torture_current_version,
1141 rcu_torture_current_version + 1);
1142 /* Cycle through nesting levels of rcu_expedite_gp() calls. */
1143 if (can_expedite &&
1144 !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
1145 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
1146 if (expediting >= 0)
1147 rcu_expedite_gp();
1148 else
1149 rcu_unexpedite_gp();
1150 if (++expediting > 3)
1151 expediting = -expediting;
1152 } else if (!can_expedite) { /* Disabled during boot, recheck. */
1153 can_expedite = !rcu_gp_is_expedited() &&
1154 !rcu_gp_is_normal();
1155 }
1156 rcu_torture_writer_state = RTWS_STUTTER;
1157 if (stutter_wait("rcu_torture_writer") &&
1158 !READ_ONCE(rcu_fwd_cb_nodelay) &&
1159 !cur_ops->slow_gps &&
1160 !torture_must_stop() &&
1161 rcu_inkernel_boot_has_ended())
1162 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++)
1163 if (list_empty(&rcu_tortures[i].rtort_free) &&
1164 rcu_access_pointer(rcu_torture_current) !=
1165 &rcu_tortures[i]) {
1166 rcu_ftrace_dump(DUMP_ALL);
1167 WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count);
1168 }
1169 } while (!torture_must_stop());
1170 rcu_torture_current = NULL; // Let stats task know that we are done.
1171 /* Reset expediting back to unexpedited. */
1172 if (expediting > 0)
1173 expediting = -expediting;
1174 while (can_expedite && expediting++ < 0)
1175 rcu_unexpedite_gp();
1176 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
1177 if (!can_expedite)
1178 pr_alert("%s" TORTURE_FLAG
1179 " Dynamic grace-period expediting was disabled.\n",
1180 torture_type);
1181 rcu_torture_writer_state = RTWS_STOPPING;
1182 torture_kthread_stopping("rcu_torture_writer");
1183 return 0;
1184}
1185
1186/*
1187 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
1188 * delay between calls.
1189 */
1190static int
1191rcu_torture_fakewriter(void *arg)
1192{
1193 DEFINE_TORTURE_RANDOM(rand);
1194
1195 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1196 set_user_nice(current, MAX_NICE);
1197
1198 do {
1199 schedule_timeout_uninterruptible(1 + torture_random(&rand)%10);
1200 udelay(torture_random(&rand) & 0x3ff);
1201 if (cur_ops->cb_barrier != NULL &&
1202 torture_random(&rand) % (nfakewriters * 8) == 0) {
1203 cur_ops->cb_barrier();
1204 } else if (gp_normal == gp_exp) {
1205 if (cur_ops->sync && torture_random(&rand) & 0x80)
1206 cur_ops->sync();
1207 else if (cur_ops->exp_sync)
1208 cur_ops->exp_sync();
1209 } else if (gp_normal && cur_ops->sync) {
1210 cur_ops->sync();
1211 } else if (cur_ops->exp_sync) {
1212 cur_ops->exp_sync();
1213 }
1214 stutter_wait("rcu_torture_fakewriter");
1215 } while (!torture_must_stop());
1216
1217 torture_kthread_stopping("rcu_torture_fakewriter");
1218 return 0;
1219}
1220
1221static void rcu_torture_timer_cb(struct rcu_head *rhp)
1222{
1223 kfree(rhp);
1224}
1225
1226/*
1227 * Do one extension of an RCU read-side critical section using the
1228 * current reader state in readstate (set to zero for initial entry
1229 * to extended critical section), set the new state as specified by
1230 * newstate (set to zero for final exit from extended critical section),
1231 * and random-number-generator state in trsp. If this is neither the
1232 * beginning or end of the critical section and if there was actually a
1233 * change, do a ->read_delay().
1234 */
1235static void rcutorture_one_extend(int *readstate, int newstate,
1236 struct torture_random_state *trsp,
1237 struct rt_read_seg *rtrsp)
1238{
1239 unsigned long flags;
1240 int idxnew = -1;
1241 int idxold = *readstate;
1242 int statesnew = ~*readstate & newstate;
1243 int statesold = *readstate & ~newstate;
1244
1245 WARN_ON_ONCE(idxold < 0);
1246 WARN_ON_ONCE((idxold >> RCUTORTURE_RDR_SHIFT) > 1);
1247 rtrsp->rt_readstate = newstate;
1248
1249 /* First, put new protection in place to avoid critical-section gap. */
1250 if (statesnew & RCUTORTURE_RDR_BH)
1251 local_bh_disable();
1252 if (statesnew & RCUTORTURE_RDR_IRQ)
1253 local_irq_disable();
1254 if (statesnew & RCUTORTURE_RDR_PREEMPT)
1255 preempt_disable();
1256 if (statesnew & RCUTORTURE_RDR_RBH)
1257 rcu_read_lock_bh();
1258 if (statesnew & RCUTORTURE_RDR_SCHED)
1259 rcu_read_lock_sched();
1260 if (statesnew & RCUTORTURE_RDR_RCU)
1261 idxnew = cur_ops->readlock() << RCUTORTURE_RDR_SHIFT;
1262
1263 /* Next, remove old protection, irq first due to bh conflict. */
1264 if (statesold & RCUTORTURE_RDR_IRQ)
1265 local_irq_enable();
1266 if (statesold & RCUTORTURE_RDR_BH)
1267 local_bh_enable();
1268 if (statesold & RCUTORTURE_RDR_PREEMPT)
1269 preempt_enable();
1270 if (statesold & RCUTORTURE_RDR_RBH)
1271 rcu_read_unlock_bh();
1272 if (statesold & RCUTORTURE_RDR_SCHED)
1273 rcu_read_unlock_sched();
1274 if (statesold & RCUTORTURE_RDR_RCU) {
1275 bool lockit = !statesnew && !(torture_random(trsp) & 0xffff);
1276
1277 if (lockit)
1278 raw_spin_lock_irqsave(¤t->pi_lock, flags);
1279 cur_ops->readunlock(idxold >> RCUTORTURE_RDR_SHIFT);
1280 if (lockit)
1281 raw_spin_unlock_irqrestore(¤t->pi_lock, flags);
1282 }
1283
1284 /* Delay if neither beginning nor end and there was a change. */
1285 if ((statesnew || statesold) && *readstate && newstate)
1286 cur_ops->read_delay(trsp, rtrsp);
1287
1288 /* Update the reader state. */
1289 if (idxnew == -1)
1290 idxnew = idxold & ~RCUTORTURE_RDR_MASK;
1291 WARN_ON_ONCE(idxnew < 0);
1292 WARN_ON_ONCE((idxnew >> RCUTORTURE_RDR_SHIFT) > 1);
1293 *readstate = idxnew | newstate;
1294 WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT) < 0);
1295 WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT) > 1);
1296}
1297
1298/* Return the biggest extendables mask given current RCU and boot parameters. */
1299static int rcutorture_extend_mask_max(void)
1300{
1301 int mask;
1302
1303 WARN_ON_ONCE(extendables & ~RCUTORTURE_MAX_EXTEND);
1304 mask = extendables & RCUTORTURE_MAX_EXTEND & cur_ops->extendables;
1305 mask = mask | RCUTORTURE_RDR_RCU;
1306 return mask;
1307}
1308
1309/* Return a random protection state mask, but with at least one bit set. */
1310static int
1311rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp)
1312{
1313 int mask = rcutorture_extend_mask_max();
1314 unsigned long randmask1 = torture_random(trsp) >> 8;
1315 unsigned long randmask2 = randmask1 >> 3;
1316
1317 WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT);
1318 /* Mostly only one bit (need preemption!), sometimes lots of bits. */
1319 if (!(randmask1 & 0x7))
1320 mask = mask & randmask2;
1321 else
1322 mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS));
1323 /* Can't enable bh w/irq disabled. */
1324 if ((mask & RCUTORTURE_RDR_IRQ) &&
1325 ((!(mask & RCUTORTURE_RDR_BH) && (oldmask & RCUTORTURE_RDR_BH)) ||
1326 (!(mask & RCUTORTURE_RDR_RBH) && (oldmask & RCUTORTURE_RDR_RBH))))
1327 mask |= RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH;
1328 return mask ?: RCUTORTURE_RDR_RCU;
1329}
1330
1331/*
1332 * Do a randomly selected number of extensions of an existing RCU read-side
1333 * critical section.
1334 */
1335static struct rt_read_seg *
1336rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp,
1337 struct rt_read_seg *rtrsp)
1338{
1339 int i;
1340 int j;
1341 int mask = rcutorture_extend_mask_max();
1342
1343 WARN_ON_ONCE(!*readstate); /* -Existing- RCU read-side critsect! */
1344 if (!((mask - 1) & mask))
1345 return rtrsp; /* Current RCU reader not extendable. */
1346 /* Bias towards larger numbers of loops. */
1347 i = (torture_random(trsp) >> 3);
1348 i = ((i | (i >> 3)) & RCUTORTURE_RDR_MAX_LOOPS) + 1;
1349 for (j = 0; j < i; j++) {
1350 mask = rcutorture_extend_mask(*readstate, trsp);
1351 rcutorture_one_extend(readstate, mask, trsp, &rtrsp[j]);
1352 }
1353 return &rtrsp[j];
1354}
1355
1356/*
1357 * Do one read-side critical section, returning false if there was
1358 * no data to read. Can be invoked both from process context and
1359 * from a timer handler.
1360 */
1361static bool rcu_torture_one_read(struct torture_random_state *trsp)
1362{
1363 int i;
1364 unsigned long started;
1365 unsigned long completed;
1366 int newstate;
1367 struct rcu_torture *p;
1368 int pipe_count;
1369 int readstate = 0;
1370 struct rt_read_seg rtseg[RCUTORTURE_RDR_MAX_SEGS] = { { 0 } };
1371 struct rt_read_seg *rtrsp = &rtseg[0];
1372 struct rt_read_seg *rtrsp1;
1373 unsigned long long ts;
1374
1375 WARN_ON_ONCE(!rcu_is_watching());
1376 newstate = rcutorture_extend_mask(readstate, trsp);
1377 rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++);
1378 started = cur_ops->get_gp_seq();
1379 ts = rcu_trace_clock_local();
1380 p = rcu_dereference_check(rcu_torture_current,
1381 rcu_read_lock_bh_held() ||
1382 rcu_read_lock_sched_held() ||
1383 srcu_read_lock_held(srcu_ctlp) ||
1384 rcu_read_lock_trace_held() ||
1385 torturing_tasks());
1386 if (p == NULL) {
1387 /* Wait for rcu_torture_writer to get underway */
1388 rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
1389 return false;
1390 }
1391 if (p->rtort_mbtest == 0)
1392 atomic_inc(&n_rcu_torture_mberror);
1393 rtrsp = rcutorture_loop_extend(&readstate, trsp, rtrsp);
1394 preempt_disable();
1395 pipe_count = READ_ONCE(p->rtort_pipe_count);
1396 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1397 /* Should not happen, but... */
1398 pipe_count = RCU_TORTURE_PIPE_LEN;
1399 }
1400 completed = cur_ops->get_gp_seq();
1401 if (pipe_count > 1) {
1402 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
1403 ts, started, completed);
1404 rcu_ftrace_dump(DUMP_ALL);
1405 }
1406 __this_cpu_inc(rcu_torture_count[pipe_count]);
1407 completed = rcutorture_seq_diff(completed, started);
1408 if (completed > RCU_TORTURE_PIPE_LEN) {
1409 /* Should not happen, but... */
1410 completed = RCU_TORTURE_PIPE_LEN;
1411 }
1412 __this_cpu_inc(rcu_torture_batch[completed]);
1413 preempt_enable();
1414 rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
1415 WARN_ON_ONCE(readstate & RCUTORTURE_RDR_MASK);
1416
1417 /* If error or close call, record the sequence of reader protections. */
1418 if ((pipe_count > 1 || completed > 1) && !xchg(&err_segs_recorded, 1)) {
1419 i = 0;
1420 for (rtrsp1 = &rtseg[0]; rtrsp1 < rtrsp; rtrsp1++)
1421 err_segs[i++] = *rtrsp1;
1422 rt_read_nsegs = i;
1423 }
1424
1425 return true;
1426}
1427
1428static DEFINE_TORTURE_RANDOM_PERCPU(rcu_torture_timer_rand);
1429
1430/*
1431 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
1432 * incrementing the corresponding element of the pipeline array. The
1433 * counter in the element should never be greater than 1, otherwise, the
1434 * RCU implementation is broken.
1435 */
1436static void rcu_torture_timer(struct timer_list *unused)
1437{
1438 atomic_long_inc(&n_rcu_torture_timers);
1439 (void)rcu_torture_one_read(this_cpu_ptr(&rcu_torture_timer_rand));
1440
1441 /* Test call_rcu() invocation from interrupt handler. */
1442 if (cur_ops->call) {
1443 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT);
1444
1445 if (rhp)
1446 cur_ops->call(rhp, rcu_torture_timer_cb);
1447 }
1448}
1449
1450/*
1451 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
1452 * incrementing the corresponding element of the pipeline array. The
1453 * counter in the element should never be greater than 1, otherwise, the
1454 * RCU implementation is broken.
1455 */
1456static int
1457rcu_torture_reader(void *arg)
1458{
1459 unsigned long lastsleep = jiffies;
1460 long myid = (long)arg;
1461 int mynumonline = myid;
1462 DEFINE_TORTURE_RANDOM(rand);
1463 struct timer_list t;
1464
1465 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
1466 set_user_nice(current, MAX_NICE);
1467 if (irqreader && cur_ops->irq_capable)
1468 timer_setup_on_stack(&t, rcu_torture_timer, 0);
1469 tick_dep_set_task(current, TICK_DEP_BIT_RCU);
1470 do {
1471 if (irqreader && cur_ops->irq_capable) {
1472 if (!timer_pending(&t))
1473 mod_timer(&t, jiffies + 1);
1474 }
1475 if (!rcu_torture_one_read(&rand) && !torture_must_stop())
1476 schedule_timeout_interruptible(HZ);
1477 if (time_after(jiffies, lastsleep) && !torture_must_stop()) {
1478 schedule_timeout_interruptible(1);
1479 lastsleep = jiffies + 10;
1480 }
1481 while (num_online_cpus() < mynumonline && !torture_must_stop())
1482 schedule_timeout_interruptible(HZ / 5);
1483 stutter_wait("rcu_torture_reader");
1484 } while (!torture_must_stop());
1485 if (irqreader && cur_ops->irq_capable) {
1486 del_timer_sync(&t);
1487 destroy_timer_on_stack(&t);
1488 }
1489 tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
1490 torture_kthread_stopping("rcu_torture_reader");
1491 return 0;
1492}
1493
1494/*
1495 * Print torture statistics. Caller must ensure that there is only
1496 * one call to this function at a given time!!! This is normally
1497 * accomplished by relying on the module system to only have one copy
1498 * of the module loaded, and then by giving the rcu_torture_stats
1499 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1500 * thread is not running).
1501 */
1502static void
1503rcu_torture_stats_print(void)
1504{
1505 int cpu;
1506 int i;
1507 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1508 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1509 struct rcu_torture *rtcp;
1510 static unsigned long rtcv_snap = ULONG_MAX;
1511 static bool splatted;
1512 struct task_struct *wtp;
1513
1514 for_each_possible_cpu(cpu) {
1515 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1516 pipesummary[i] += READ_ONCE(per_cpu(rcu_torture_count, cpu)[i]);
1517 batchsummary[i] += READ_ONCE(per_cpu(rcu_torture_batch, cpu)[i]);
1518 }
1519 }
1520 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
1521 if (pipesummary[i] != 0)
1522 break;
1523 }
1524
1525 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1526 rtcp = rcu_access_pointer(rcu_torture_current);
1527 pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
1528 rtcp,
1529 rtcp && !rcu_stall_is_suppressed_at_boot() ? "ver" : "VER",
1530 rcu_torture_current_version,
1531 list_empty(&rcu_torture_freelist),
1532 atomic_read(&n_rcu_torture_alloc),
1533 atomic_read(&n_rcu_torture_alloc_fail),
1534 atomic_read(&n_rcu_torture_free));
1535 pr_cont("rtmbe: %d rtbe: %ld rtbke: %ld rtbre: %ld ",
1536 atomic_read(&n_rcu_torture_mberror),
1537 n_rcu_torture_barrier_error,
1538 n_rcu_torture_boost_ktrerror,
1539 n_rcu_torture_boost_rterror);
1540 pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
1541 n_rcu_torture_boost_failure,
1542 n_rcu_torture_boosts,
1543 atomic_long_read(&n_rcu_torture_timers));
1544 torture_onoff_stats();
1545 pr_cont("barrier: %ld/%ld:%ld ",
1546 data_race(n_barrier_successes),
1547 data_race(n_barrier_attempts),
1548 data_race(n_rcu_torture_barrier_error));
1549 pr_cont("read-exits: %ld\n", data_race(n_read_exits));
1550
1551 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1552 if (atomic_read(&n_rcu_torture_mberror) ||
1553 n_rcu_torture_barrier_error || n_rcu_torture_boost_ktrerror ||
1554 n_rcu_torture_boost_rterror || n_rcu_torture_boost_failure ||
1555 i > 1) {
1556 pr_cont("%s", "!!! ");
1557 atomic_inc(&n_rcu_torture_error);
1558 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mberror));
1559 WARN_ON_ONCE(n_rcu_torture_barrier_error); // rcu_barrier()
1560 WARN_ON_ONCE(n_rcu_torture_boost_ktrerror); // no boost kthread
1561 WARN_ON_ONCE(n_rcu_torture_boost_rterror); // can't set RT prio
1562 WARN_ON_ONCE(n_rcu_torture_boost_failure); // RCU boost failed
1563 WARN_ON_ONCE(i > 1); // Too-short grace period
1564 }
1565 pr_cont("Reader Pipe: ");
1566 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1567 pr_cont(" %ld", pipesummary[i]);
1568 pr_cont("\n");
1569
1570 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1571 pr_cont("Reader Batch: ");
1572 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1573 pr_cont(" %ld", batchsummary[i]);
1574 pr_cont("\n");
1575
1576 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1577 pr_cont("Free-Block Circulation: ");
1578 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1579 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
1580 }
1581 pr_cont("\n");
1582
1583 if (cur_ops->stats)
1584 cur_ops->stats();
1585 if (rtcv_snap == rcu_torture_current_version &&
1586 rcu_access_pointer(rcu_torture_current) &&
1587 !rcu_stall_is_suppressed()) {
1588 int __maybe_unused flags = 0;
1589 unsigned long __maybe_unused gp_seq = 0;
1590
1591 rcutorture_get_gp_data(cur_ops->ttype,
1592 &flags, &gp_seq);
1593 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp,
1594 &flags, &gp_seq);
1595 wtp = READ_ONCE(writer_task);
1596 pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#lx cpu %d\n",
1597 rcu_torture_writer_state_getname(),
1598 rcu_torture_writer_state, gp_seq, flags,
1599 wtp == NULL ? ~0UL : wtp->state,
1600 wtp == NULL ? -1 : (int)task_cpu(wtp));
1601 if (!splatted && wtp) {
1602 sched_show_task(wtp);
1603 splatted = true;
1604 }
1605 show_rcu_gp_kthreads();
1606 rcu_ftrace_dump(DUMP_ALL);
1607 }
1608 rtcv_snap = rcu_torture_current_version;
1609}
1610
1611/*
1612 * Periodically prints torture statistics, if periodic statistics printing
1613 * was specified via the stat_interval module parameter.
1614 */
1615static int
1616rcu_torture_stats(void *arg)
1617{
1618 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1619 do {
1620 schedule_timeout_interruptible(stat_interval * HZ);
1621 rcu_torture_stats_print();
1622 torture_shutdown_absorb("rcu_torture_stats");
1623 } while (!torture_must_stop());
1624 torture_kthread_stopping("rcu_torture_stats");
1625 return 0;
1626}
1627
1628static void
1629rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1630{
1631 pr_alert("%s" TORTURE_FLAG
1632 "--- %s: nreaders=%d nfakewriters=%d "
1633 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1634 "shuffle_interval=%d stutter=%d irqreader=%d "
1635 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1636 "test_boost=%d/%d test_boost_interval=%d "
1637 "test_boost_duration=%d shutdown_secs=%d "
1638 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d "
1639 "stall_cpu_block=%d "
1640 "n_barrier_cbs=%d "
1641 "onoff_interval=%d onoff_holdoff=%d "
1642 "read_exit_delay=%d read_exit_burst=%d\n",
1643 torture_type, tag, nrealreaders, nfakewriters,
1644 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1645 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1646 test_boost, cur_ops->can_boost,
1647 test_boost_interval, test_boost_duration, shutdown_secs,
1648 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff,
1649 stall_cpu_block,
1650 n_barrier_cbs,
1651 onoff_interval, onoff_holdoff,
1652 read_exit_delay, read_exit_burst);
1653}
1654
1655static int rcutorture_booster_cleanup(unsigned int cpu)
1656{
1657 struct task_struct *t;
1658
1659 if (boost_tasks[cpu] == NULL)
1660 return 0;
1661 mutex_lock(&boost_mutex);
1662 t = boost_tasks[cpu];
1663 boost_tasks[cpu] = NULL;
1664 rcu_torture_enable_rt_throttle();
1665 mutex_unlock(&boost_mutex);
1666
1667 /* This must be outside of the mutex, otherwise deadlock! */
1668 torture_stop_kthread(rcu_torture_boost, t);
1669 return 0;
1670}
1671
1672static int rcutorture_booster_init(unsigned int cpu)
1673{
1674 int retval;
1675
1676 if (boost_tasks[cpu] != NULL)
1677 return 0; /* Already created, nothing more to do. */
1678
1679 /* Don't allow time recalculation while creating a new task. */
1680 mutex_lock(&boost_mutex);
1681 rcu_torture_disable_rt_throttle();
1682 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
1683 boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
1684 cpu_to_node(cpu),
1685 "rcu_torture_boost");
1686 if (IS_ERR(boost_tasks[cpu])) {
1687 retval = PTR_ERR(boost_tasks[cpu]);
1688 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
1689 n_rcu_torture_boost_ktrerror++;
1690 boost_tasks[cpu] = NULL;
1691 mutex_unlock(&boost_mutex);
1692 return retval;
1693 }
1694 kthread_bind(boost_tasks[cpu], cpu);
1695 wake_up_process(boost_tasks[cpu]);
1696 mutex_unlock(&boost_mutex);
1697 return 0;
1698}
1699
1700/*
1701 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
1702 * induces a CPU stall for the time specified by stall_cpu.
1703 */
1704static int rcu_torture_stall(void *args)
1705{
1706 int idx;
1707 unsigned long stop_at;
1708
1709 VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
1710 if (stall_cpu_holdoff > 0) {
1711 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
1712 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
1713 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
1714 }
1715 if (!kthread_should_stop() && stall_gp_kthread > 0) {
1716 VERBOSE_TOROUT_STRING("rcu_torture_stall begin GP stall");
1717 rcu_gp_set_torture_wait(stall_gp_kthread * HZ);
1718 for (idx = 0; idx < stall_gp_kthread + 2; idx++) {
1719 if (kthread_should_stop())
1720 break;
1721 schedule_timeout_uninterruptible(HZ);
1722 }
1723 }
1724 if (!kthread_should_stop() && stall_cpu > 0) {
1725 VERBOSE_TOROUT_STRING("rcu_torture_stall begin CPU stall");
1726 stop_at = ktime_get_seconds() + stall_cpu;
1727 /* RCU CPU stall is expected behavior in following code. */
1728 idx = cur_ops->readlock();
1729 if (stall_cpu_irqsoff)
1730 local_irq_disable();
1731 else if (!stall_cpu_block)
1732 preempt_disable();
1733 pr_alert("rcu_torture_stall start on CPU %d.\n",
1734 raw_smp_processor_id());
1735 while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(),
1736 stop_at))
1737 if (stall_cpu_block)
1738 schedule_timeout_uninterruptible(HZ);
1739 if (stall_cpu_irqsoff)
1740 local_irq_enable();
1741 else if (!stall_cpu_block)
1742 preempt_enable();
1743 cur_ops->readunlock(idx);
1744 }
1745 pr_alert("rcu_torture_stall end.\n");
1746 torture_shutdown_absorb("rcu_torture_stall");
1747 while (!kthread_should_stop())
1748 schedule_timeout_interruptible(10 * HZ);
1749 return 0;
1750}
1751
1752/* Spawn CPU-stall kthread, if stall_cpu specified. */
1753static int __init rcu_torture_stall_init(void)
1754{
1755 if (stall_cpu <= 0 && stall_gp_kthread <= 0)
1756 return 0;
1757 return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
1758}
1759
1760/* State structure for forward-progress self-propagating RCU callback. */
1761struct fwd_cb_state {
1762 struct rcu_head rh;
1763 int stop;
1764};
1765
1766/*
1767 * Forward-progress self-propagating RCU callback function. Because
1768 * callbacks run from softirq, this function is an implicit RCU read-side
1769 * critical section.
1770 */
1771static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp)
1772{
1773 struct fwd_cb_state *fcsp = container_of(rhp, struct fwd_cb_state, rh);
1774
1775 if (READ_ONCE(fcsp->stop)) {
1776 WRITE_ONCE(fcsp->stop, 2);
1777 return;
1778 }
1779 cur_ops->call(&fcsp->rh, rcu_torture_fwd_prog_cb);
1780}
1781
1782/* State for continuous-flood RCU callbacks. */
1783struct rcu_fwd_cb {
1784 struct rcu_head rh;
1785 struct rcu_fwd_cb *rfc_next;
1786 struct rcu_fwd *rfc_rfp;
1787 int rfc_gps;
1788};
1789
1790#define MAX_FWD_CB_JIFFIES (8 * HZ) /* Maximum CB test duration. */
1791#define MIN_FWD_CB_LAUNDERS 3 /* This many CB invocations to count. */
1792#define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */
1793#define FWD_CBS_HIST_DIV 10 /* Histogram buckets/second. */
1794#define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV))
1795
1796struct rcu_launder_hist {
1797 long n_launders;
1798 unsigned long launder_gp_seq;
1799};
1800
1801struct rcu_fwd {
1802 spinlock_t rcu_fwd_lock;
1803 struct rcu_fwd_cb *rcu_fwd_cb_head;
1804 struct rcu_fwd_cb **rcu_fwd_cb_tail;
1805 long n_launders_cb;
1806 unsigned long rcu_fwd_startat;
1807 struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST];
1808 unsigned long rcu_launder_gp_seq_start;
1809};
1810
1811static struct rcu_fwd *rcu_fwds;
1812static bool rcu_fwd_emergency_stop;
1813
1814static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp)
1815{
1816 unsigned long gps;
1817 unsigned long gps_old;
1818 int i;
1819 int j;
1820
1821 for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--)
1822 if (rfp->n_launders_hist[i].n_launders > 0)
1823 break;
1824 pr_alert("%s: Callback-invocation histogram (duration %lu jiffies):",
1825 __func__, jiffies - rfp->rcu_fwd_startat);
1826 gps_old = rfp->rcu_launder_gp_seq_start;
1827 for (j = 0; j <= i; j++) {
1828 gps = rfp->n_launders_hist[j].launder_gp_seq;
1829 pr_cont(" %ds/%d: %ld:%ld",
1830 j + 1, FWD_CBS_HIST_DIV,
1831 rfp->n_launders_hist[j].n_launders,
1832 rcutorture_seq_diff(gps, gps_old));
1833 gps_old = gps;
1834 }
1835 pr_cont("\n");
1836}
1837
1838/* Callback function for continuous-flood RCU callbacks. */
1839static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp)
1840{
1841 unsigned long flags;
1842 int i;
1843 struct rcu_fwd_cb *rfcp = container_of(rhp, struct rcu_fwd_cb, rh);
1844 struct rcu_fwd_cb **rfcpp;
1845 struct rcu_fwd *rfp = rfcp->rfc_rfp;
1846
1847 rfcp->rfc_next = NULL;
1848 rfcp->rfc_gps++;
1849 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
1850 rfcpp = rfp->rcu_fwd_cb_tail;
1851 rfp->rcu_fwd_cb_tail = &rfcp->rfc_next;
1852 WRITE_ONCE(*rfcpp, rfcp);
1853 WRITE_ONCE(rfp->n_launders_cb, rfp->n_launders_cb + 1);
1854 i = ((jiffies - rfp->rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV));
1855 if (i >= ARRAY_SIZE(rfp->n_launders_hist))
1856 i = ARRAY_SIZE(rfp->n_launders_hist) - 1;
1857 rfp->n_launders_hist[i].n_launders++;
1858 rfp->n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq();
1859 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
1860}
1861
1862// Give the scheduler a chance, even on nohz_full CPUs.
1863static void rcu_torture_fwd_prog_cond_resched(unsigned long iter)
1864{
1865 if (IS_ENABLED(CONFIG_PREEMPTION) && IS_ENABLED(CONFIG_NO_HZ_FULL)) {
1866 // Real call_rcu() floods hit userspace, so emulate that.
1867 if (need_resched() || (iter & 0xfff))
1868 schedule();
1869 return;
1870 }
1871 // No userspace emulation: CB invocation throttles call_rcu()
1872 cond_resched();
1873}
1874
1875/*
1876 * Free all callbacks on the rcu_fwd_cb_head list, either because the
1877 * test is over or because we hit an OOM event.
1878 */
1879static unsigned long rcu_torture_fwd_prog_cbfree(struct rcu_fwd *rfp)
1880{
1881 unsigned long flags;
1882 unsigned long freed = 0;
1883 struct rcu_fwd_cb *rfcp;
1884
1885 for (;;) {
1886 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
1887 rfcp = rfp->rcu_fwd_cb_head;
1888 if (!rfcp) {
1889 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
1890 break;
1891 }
1892 rfp->rcu_fwd_cb_head = rfcp->rfc_next;
1893 if (!rfp->rcu_fwd_cb_head)
1894 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head;
1895 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
1896 kfree(rfcp);
1897 freed++;
1898 rcu_torture_fwd_prog_cond_resched(freed);
1899 if (tick_nohz_full_enabled()) {
1900 local_irq_save(flags);
1901 rcu_momentary_dyntick_idle();
1902 local_irq_restore(flags);
1903 }
1904 }
1905 return freed;
1906}
1907
1908/* Carry out need_resched()/cond_resched() forward-progress testing. */
1909static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp,
1910 int *tested, int *tested_tries)
1911{
1912 unsigned long cver;
1913 unsigned long dur;
1914 struct fwd_cb_state fcs;
1915 unsigned long gps;
1916 int idx;
1917 int sd;
1918 int sd4;
1919 bool selfpropcb = false;
1920 unsigned long stopat;
1921 static DEFINE_TORTURE_RANDOM(trs);
1922
1923 if (cur_ops->call && cur_ops->sync && cur_ops->cb_barrier) {
1924 init_rcu_head_on_stack(&fcs.rh);
1925 selfpropcb = true;
1926 }
1927
1928 /* Tight loop containing cond_resched(). */
1929 WRITE_ONCE(rcu_fwd_cb_nodelay, true);
1930 cur_ops->sync(); /* Later readers see above write. */
1931 if (selfpropcb) {
1932 WRITE_ONCE(fcs.stop, 0);
1933 cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb);
1934 }
1935 cver = READ_ONCE(rcu_torture_current_version);
1936 gps = cur_ops->get_gp_seq();
1937 sd = cur_ops->stall_dur() + 1;
1938 sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div;
1939 dur = sd4 + torture_random(&trs) % (sd - sd4);
1940 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
1941 stopat = rfp->rcu_fwd_startat + dur;
1942 while (time_before(jiffies, stopat) &&
1943 !shutdown_time_arrived() &&
1944 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
1945 idx = cur_ops->readlock();
1946 udelay(10);
1947 cur_ops->readunlock(idx);
1948 if (!fwd_progress_need_resched || need_resched())
1949 cond_resched();
1950 }
1951 (*tested_tries)++;
1952 if (!time_before(jiffies, stopat) &&
1953 !shutdown_time_arrived() &&
1954 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
1955 (*tested)++;
1956 cver = READ_ONCE(rcu_torture_current_version) - cver;
1957 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
1958 WARN_ON(!cver && gps < 2);
1959 pr_alert("%s: Duration %ld cver %ld gps %ld\n", __func__, dur, cver, gps);
1960 }
1961 if (selfpropcb) {
1962 WRITE_ONCE(fcs.stop, 1);
1963 cur_ops->sync(); /* Wait for running CB to complete. */
1964 cur_ops->cb_barrier(); /* Wait for queued callbacks. */
1965 }
1966
1967 if (selfpropcb) {
1968 WARN_ON(READ_ONCE(fcs.stop) != 2);
1969 destroy_rcu_head_on_stack(&fcs.rh);
1970 }
1971 schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */
1972 WRITE_ONCE(rcu_fwd_cb_nodelay, false);
1973}
1974
1975/* Carry out call_rcu() forward-progress testing. */
1976static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp)
1977{
1978 unsigned long cver;
1979 unsigned long flags;
1980 unsigned long gps;
1981 int i;
1982 long n_launders;
1983 long n_launders_cb_snap;
1984 long n_launders_sa;
1985 long n_max_cbs;
1986 long n_max_gps;
1987 struct rcu_fwd_cb *rfcp;
1988 struct rcu_fwd_cb *rfcpn;
1989 unsigned long stopat;
1990 unsigned long stoppedat;
1991
1992 if (READ_ONCE(rcu_fwd_emergency_stop))
1993 return; /* Get out of the way quickly, no GP wait! */
1994 if (!cur_ops->call)
1995 return; /* Can't do call_rcu() fwd prog without ->call. */
1996
1997 /* Loop continuously posting RCU callbacks. */
1998 WRITE_ONCE(rcu_fwd_cb_nodelay, true);
1999 cur_ops->sync(); /* Later readers see above write. */
2000 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
2001 stopat = rfp->rcu_fwd_startat + MAX_FWD_CB_JIFFIES;
2002 n_launders = 0;
2003 rfp->n_launders_cb = 0; // Hoist initialization for multi-kthread
2004 n_launders_sa = 0;
2005 n_max_cbs = 0;
2006 n_max_gps = 0;
2007 for (i = 0; i < ARRAY_SIZE(rfp->n_launders_hist); i++)
2008 rfp->n_launders_hist[i].n_launders = 0;
2009 cver = READ_ONCE(rcu_torture_current_version);
2010 gps = cur_ops->get_gp_seq();
2011 rfp->rcu_launder_gp_seq_start = gps;
2012 tick_dep_set_task(current, TICK_DEP_BIT_RCU);
2013 while (time_before(jiffies, stopat) &&
2014 !shutdown_time_arrived() &&
2015 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
2016 rfcp = READ_ONCE(rfp->rcu_fwd_cb_head);
2017 rfcpn = NULL;
2018 if (rfcp)
2019 rfcpn = READ_ONCE(rfcp->rfc_next);
2020 if (rfcpn) {
2021 if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS &&
2022 ++n_max_gps >= MIN_FWD_CBS_LAUNDERED)
2023 break;
2024 rfp->rcu_fwd_cb_head = rfcpn;
2025 n_launders++;
2026 n_launders_sa++;
2027 } else {
2028 rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL);
2029 if (WARN_ON_ONCE(!rfcp)) {
2030 schedule_timeout_interruptible(1);
2031 continue;
2032 }
2033 n_max_cbs++;
2034 n_launders_sa = 0;
2035 rfcp->rfc_gps = 0;
2036 rfcp->rfc_rfp = rfp;
2037 }
2038 cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr);
2039 rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs);
2040 if (tick_nohz_full_enabled()) {
2041 local_irq_save(flags);
2042 rcu_momentary_dyntick_idle();
2043 local_irq_restore(flags);
2044 }
2045 }
2046 stoppedat = jiffies;
2047 n_launders_cb_snap = READ_ONCE(rfp->n_launders_cb);
2048 cver = READ_ONCE(rcu_torture_current_version) - cver;
2049 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
2050 cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */
2051 (void)rcu_torture_fwd_prog_cbfree(rfp);
2052
2053 if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) &&
2054 !shutdown_time_arrived()) {
2055 WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED);
2056 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",
2057 __func__,
2058 stoppedat - rfp->rcu_fwd_startat, jiffies - stoppedat,
2059 n_launders + n_max_cbs - n_launders_cb_snap,
2060 n_launders, n_launders_sa,
2061 n_max_gps, n_max_cbs, cver, gps);
2062 rcu_torture_fwd_cb_hist(rfp);
2063 }
2064 schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */
2065 tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
2066 WRITE_ONCE(rcu_fwd_cb_nodelay, false);
2067}
2068
2069
2070/*
2071 * OOM notifier, but this only prints diagnostic information for the
2072 * current forward-progress test.
2073 */
2074static int rcutorture_oom_notify(struct notifier_block *self,
2075 unsigned long notused, void *nfreed)
2076{
2077 struct rcu_fwd *rfp = rcu_fwds;
2078
2079 WARN(1, "%s invoked upon OOM during forward-progress testing.\n",
2080 __func__);
2081 rcu_torture_fwd_cb_hist(rfp);
2082 rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp->rcu_fwd_startat)) / 2);
2083 WRITE_ONCE(rcu_fwd_emergency_stop, true);
2084 smp_mb(); /* Emergency stop before free and wait to avoid hangs. */
2085 pr_info("%s: Freed %lu RCU callbacks.\n",
2086 __func__, rcu_torture_fwd_prog_cbfree(rfp));
2087 rcu_barrier();
2088 pr_info("%s: Freed %lu RCU callbacks.\n",
2089 __func__, rcu_torture_fwd_prog_cbfree(rfp));
2090 rcu_barrier();
2091 pr_info("%s: Freed %lu RCU callbacks.\n",
2092 __func__, rcu_torture_fwd_prog_cbfree(rfp));
2093 smp_mb(); /* Frees before return to avoid redoing OOM. */
2094 (*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */
2095 pr_info("%s returning after OOM processing.\n", __func__);
2096 return NOTIFY_OK;
2097}
2098
2099static struct notifier_block rcutorture_oom_nb = {
2100 .notifier_call = rcutorture_oom_notify
2101};
2102
2103/* Carry out grace-period forward-progress testing. */
2104static int rcu_torture_fwd_prog(void *args)
2105{
2106 struct rcu_fwd *rfp = args;
2107 int tested = 0;
2108 int tested_tries = 0;
2109
2110 VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started");
2111 rcu_bind_current_to_nocb();
2112 if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST))
2113 set_user_nice(current, MAX_NICE);
2114 do {
2115 schedule_timeout_interruptible(fwd_progress_holdoff * HZ);
2116 WRITE_ONCE(rcu_fwd_emergency_stop, false);
2117 register_oom_notifier(&rcutorture_oom_nb);
2118 if (!IS_ENABLED(CONFIG_TINY_RCU) ||
2119 rcu_inkernel_boot_has_ended())
2120 rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries);
2121 if (rcu_inkernel_boot_has_ended())
2122 rcu_torture_fwd_prog_cr(rfp);
2123 unregister_oom_notifier(&rcutorture_oom_nb);
2124
2125 /* Avoid slow periods, better to test when busy. */
2126 stutter_wait("rcu_torture_fwd_prog");
2127 } while (!torture_must_stop());
2128 /* Short runs might not contain a valid forward-progress attempt. */
2129 WARN_ON(!tested && tested_tries >= 5);
2130 pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries);
2131 torture_kthread_stopping("rcu_torture_fwd_prog");
2132 return 0;
2133}
2134
2135/* If forward-progress checking is requested and feasible, spawn the thread. */
2136static int __init rcu_torture_fwd_prog_init(void)
2137{
2138 struct rcu_fwd *rfp;
2139
2140 if (!fwd_progress)
2141 return 0; /* Not requested, so don't do it. */
2142 if (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0 ||
2143 cur_ops == &rcu_busted_ops) {
2144 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test");
2145 return 0;
2146 }
2147 if (stall_cpu > 0) {
2148 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing");
2149 if (IS_MODULE(CONFIG_RCU_TORTURE_TESTS))
2150 return -EINVAL; /* In module, can fail back to user. */
2151 WARN_ON(1); /* Make sure rcutorture notices conflict. */
2152 return 0;
2153 }
2154 if (fwd_progress_holdoff <= 0)
2155 fwd_progress_holdoff = 1;
2156 if (fwd_progress_div <= 0)
2157 fwd_progress_div = 4;
2158 rfp = kzalloc(sizeof(*rfp), GFP_KERNEL);
2159 if (!rfp)
2160 return -ENOMEM;
2161 spin_lock_init(&rfp->rcu_fwd_lock);
2162 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head;
2163 return torture_create_kthread(rcu_torture_fwd_prog, rfp, fwd_prog_task);
2164}
2165
2166/* Callback function for RCU barrier testing. */
2167static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
2168{
2169 atomic_inc(&barrier_cbs_invoked);
2170}
2171
2172/* IPI handler to get callback posted on desired CPU, if online. */
2173static void rcu_torture_barrier1cb(void *rcu_void)
2174{
2175 struct rcu_head *rhp = rcu_void;
2176
2177 cur_ops->call(rhp, rcu_torture_barrier_cbf);
2178}
2179
2180/* kthread function to register callbacks used to test RCU barriers. */
2181static int rcu_torture_barrier_cbs(void *arg)
2182{
2183 long myid = (long)arg;
2184 bool lastphase = false;
2185 bool newphase;
2186 struct rcu_head rcu;
2187
2188 init_rcu_head_on_stack(&rcu);
2189 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
2190 set_user_nice(current, MAX_NICE);
2191 do {
2192 wait_event(barrier_cbs_wq[myid],
2193 (newphase =
2194 smp_load_acquire(&barrier_phase)) != lastphase ||
2195 torture_must_stop());
2196 lastphase = newphase;
2197 if (torture_must_stop())
2198 break;
2199 /*
2200 * The above smp_load_acquire() ensures barrier_phase load
2201 * is ordered before the following ->call().
2202 */
2203 if (smp_call_function_single(myid, rcu_torture_barrier1cb,
2204 &rcu, 1)) {
2205 // IPI failed, so use direct call from current CPU.
2206 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
2207 }
2208 if (atomic_dec_and_test(&barrier_cbs_count))
2209 wake_up(&barrier_wq);
2210 } while (!torture_must_stop());
2211 if (cur_ops->cb_barrier != NULL)
2212 cur_ops->cb_barrier();
2213 destroy_rcu_head_on_stack(&rcu);
2214 torture_kthread_stopping("rcu_torture_barrier_cbs");
2215 return 0;
2216}
2217
2218/* kthread function to drive and coordinate RCU barrier testing. */
2219static int rcu_torture_barrier(void *arg)
2220{
2221 int i;
2222
2223 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
2224 do {
2225 atomic_set(&barrier_cbs_invoked, 0);
2226 atomic_set(&barrier_cbs_count, n_barrier_cbs);
2227 /* Ensure barrier_phase ordered after prior assignments. */
2228 smp_store_release(&barrier_phase, !barrier_phase);
2229 for (i = 0; i < n_barrier_cbs; i++)
2230 wake_up(&barrier_cbs_wq[i]);
2231 wait_event(barrier_wq,
2232 atomic_read(&barrier_cbs_count) == 0 ||
2233 torture_must_stop());
2234 if (torture_must_stop())
2235 break;
2236 n_barrier_attempts++;
2237 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
2238 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
2239 n_rcu_torture_barrier_error++;
2240 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
2241 atomic_read(&barrier_cbs_invoked),
2242 n_barrier_cbs);
2243 WARN_ON(1);
2244 // Wait manually for the remaining callbacks
2245 i = 0;
2246 do {
2247 if (WARN_ON(i++ > HZ))
2248 i = INT_MIN;
2249 schedule_timeout_interruptible(1);
2250 cur_ops->cb_barrier();
2251 } while (atomic_read(&barrier_cbs_invoked) !=
2252 n_barrier_cbs &&
2253 !torture_must_stop());
2254 smp_mb(); // Can't trust ordering if broken.
2255 if (!torture_must_stop())
2256 pr_err("Recovered: barrier_cbs_invoked = %d\n",
2257 atomic_read(&barrier_cbs_invoked));
2258 } else {
2259 n_barrier_successes++;
2260 }
2261 schedule_timeout_interruptible(HZ / 10);
2262 } while (!torture_must_stop());
2263 torture_kthread_stopping("rcu_torture_barrier");
2264 return 0;
2265}
2266
2267/* Initialize RCU barrier testing. */
2268static int rcu_torture_barrier_init(void)
2269{
2270 int i;
2271 int ret;
2272
2273 if (n_barrier_cbs <= 0)
2274 return 0;
2275 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
2276 pr_alert("%s" TORTURE_FLAG
2277 " Call or barrier ops missing for %s,\n",
2278 torture_type, cur_ops->name);
2279 pr_alert("%s" TORTURE_FLAG
2280 " RCU barrier testing omitted from run.\n",
2281 torture_type);
2282 return 0;
2283 }
2284 atomic_set(&barrier_cbs_count, 0);
2285 atomic_set(&barrier_cbs_invoked, 0);
2286 barrier_cbs_tasks =
2287 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]),
2288 GFP_KERNEL);
2289 barrier_cbs_wq =
2290 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL);
2291 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
2292 return -ENOMEM;
2293 for (i = 0; i < n_barrier_cbs; i++) {
2294 init_waitqueue_head(&barrier_cbs_wq[i]);
2295 ret = torture_create_kthread(rcu_torture_barrier_cbs,
2296 (void *)(long)i,
2297 barrier_cbs_tasks[i]);
2298 if (ret)
2299 return ret;
2300 }
2301 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
2302}
2303
2304/* Clean up after RCU barrier testing. */
2305static void rcu_torture_barrier_cleanup(void)
2306{
2307 int i;
2308
2309 torture_stop_kthread(rcu_torture_barrier, barrier_task);
2310 if (barrier_cbs_tasks != NULL) {
2311 for (i = 0; i < n_barrier_cbs; i++)
2312 torture_stop_kthread(rcu_torture_barrier_cbs,
2313 barrier_cbs_tasks[i]);
2314 kfree(barrier_cbs_tasks);
2315 barrier_cbs_tasks = NULL;
2316 }
2317 if (barrier_cbs_wq != NULL) {
2318 kfree(barrier_cbs_wq);
2319 barrier_cbs_wq = NULL;
2320 }
2321}
2322
2323static bool rcu_torture_can_boost(void)
2324{
2325 static int boost_warn_once;
2326 int prio;
2327
2328 if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2)
2329 return false;
2330
2331 prio = rcu_get_gp_kthreads_prio();
2332 if (!prio)
2333 return false;
2334
2335 if (prio < 2) {
2336 if (boost_warn_once == 1)
2337 return false;
2338
2339 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);
2340 boost_warn_once = 1;
2341 return false;
2342 }
2343
2344 return true;
2345}
2346
2347static bool read_exit_child_stop;
2348static bool read_exit_child_stopped;
2349static wait_queue_head_t read_exit_wq;
2350
2351// Child kthread which just does an rcutorture reader and exits.
2352static int rcu_torture_read_exit_child(void *trsp_in)
2353{
2354 struct torture_random_state *trsp = trsp_in;
2355
2356 set_user_nice(current, MAX_NICE);
2357 // Minimize time between reading and exiting.
2358 while (!kthread_should_stop())
2359 schedule_timeout_uninterruptible(1);
2360 (void)rcu_torture_one_read(trsp);
2361 return 0;
2362}
2363
2364// Parent kthread which creates and destroys read-exit child kthreads.
2365static int rcu_torture_read_exit(void *unused)
2366{
2367 int count = 0;
2368 bool errexit = false;
2369 int i;
2370 struct task_struct *tsp;
2371 DEFINE_TORTURE_RANDOM(trs);
2372
2373 // Allocate and initialize.
2374 set_user_nice(current, MAX_NICE);
2375 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of test");
2376
2377 // Each pass through this loop does one read-exit episode.
2378 do {
2379 if (++count > read_exit_burst) {
2380 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: End of episode");
2381 rcu_barrier(); // Wait for task_struct free, avoid OOM.
2382 for (i = 0; i < read_exit_delay; i++) {
2383 schedule_timeout_uninterruptible(HZ);
2384 if (READ_ONCE(read_exit_child_stop))
2385 break;
2386 }
2387 if (!READ_ONCE(read_exit_child_stop))
2388 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of episode");
2389 count = 0;
2390 }
2391 if (READ_ONCE(read_exit_child_stop))
2392 break;
2393 // Spawn child.
2394 tsp = kthread_run(rcu_torture_read_exit_child,
2395 &trs, "%s",
2396 "rcu_torture_read_exit_child");
2397 if (IS_ERR(tsp)) {
2398 VERBOSE_TOROUT_ERRSTRING("out of memory");
2399 errexit = true;
2400 tsp = NULL;
2401 break;
2402 }
2403 cond_resched();
2404 kthread_stop(tsp);
2405 n_read_exits ++;
2406 stutter_wait("rcu_torture_read_exit");
2407 } while (!errexit && !READ_ONCE(read_exit_child_stop));
2408
2409 // Clean up and exit.
2410 smp_store_release(&read_exit_child_stopped, true); // After reaping.
2411 smp_mb(); // Store before wakeup.
2412 wake_up(&read_exit_wq);
2413 while (!torture_must_stop())
2414 schedule_timeout_uninterruptible(1);
2415 torture_kthread_stopping("rcu_torture_read_exit");
2416 return 0;
2417}
2418
2419static int rcu_torture_read_exit_init(void)
2420{
2421 if (read_exit_burst <= 0)
2422 return -EINVAL;
2423 init_waitqueue_head(&read_exit_wq);
2424 read_exit_child_stop = false;
2425 read_exit_child_stopped = false;
2426 return torture_create_kthread(rcu_torture_read_exit, NULL,
2427 read_exit_task);
2428}
2429
2430static void rcu_torture_read_exit_cleanup(void)
2431{
2432 if (!read_exit_task)
2433 return;
2434 WRITE_ONCE(read_exit_child_stop, true);
2435 smp_mb(); // Above write before wait.
2436 wait_event(read_exit_wq, smp_load_acquire(&read_exit_child_stopped));
2437 torture_stop_kthread(rcutorture_read_exit, read_exit_task);
2438}
2439
2440static enum cpuhp_state rcutor_hp;
2441
2442static void
2443rcu_torture_cleanup(void)
2444{
2445 int firsttime;
2446 int flags = 0;
2447 unsigned long gp_seq = 0;
2448 int i;
2449
2450 if (torture_cleanup_begin()) {
2451 if (cur_ops->cb_barrier != NULL)
2452 cur_ops->cb_barrier();
2453 return;
2454 }
2455 if (!cur_ops) {
2456 torture_cleanup_end();
2457 return;
2458 }
2459
2460 show_rcu_gp_kthreads();
2461 rcu_torture_read_exit_cleanup();
2462 rcu_torture_barrier_cleanup();
2463 torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_task);
2464 torture_stop_kthread(rcu_torture_stall, stall_task);
2465 torture_stop_kthread(rcu_torture_writer, writer_task);
2466
2467 if (reader_tasks) {
2468 for (i = 0; i < nrealreaders; i++)
2469 torture_stop_kthread(rcu_torture_reader,
2470 reader_tasks[i]);
2471 kfree(reader_tasks);
2472 }
2473
2474 if (fakewriter_tasks) {
2475 for (i = 0; i < nfakewriters; i++) {
2476 torture_stop_kthread(rcu_torture_fakewriter,
2477 fakewriter_tasks[i]);
2478 }
2479 kfree(fakewriter_tasks);
2480 fakewriter_tasks = NULL;
2481 }
2482
2483 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq);
2484 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq);
2485 pr_alert("%s: End-test grace-period state: g%lu f%#x\n",
2486 cur_ops->name, gp_seq, flags);
2487 torture_stop_kthread(rcu_torture_stats, stats_task);
2488 torture_stop_kthread(rcu_torture_fqs, fqs_task);
2489 if (rcu_torture_can_boost())
2490 cpuhp_remove_state(rcutor_hp);
2491
2492 /*
2493 * Wait for all RCU callbacks to fire, then do torture-type-specific
2494 * cleanup operations.
2495 */
2496 if (cur_ops->cb_barrier != NULL)
2497 cur_ops->cb_barrier();
2498 if (cur_ops->cleanup != NULL)
2499 cur_ops->cleanup();
2500
2501 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
2502
2503 if (err_segs_recorded) {
2504 pr_alert("Failure/close-call rcutorture reader segments:\n");
2505 if (rt_read_nsegs == 0)
2506 pr_alert("\t: No segments recorded!!!\n");
2507 firsttime = 1;
2508 for (i = 0; i < rt_read_nsegs; i++) {
2509 pr_alert("\t%d: %#x ", i, err_segs[i].rt_readstate);
2510 if (err_segs[i].rt_delay_jiffies != 0) {
2511 pr_cont("%s%ldjiffies", firsttime ? "" : "+",
2512 err_segs[i].rt_delay_jiffies);
2513 firsttime = 0;
2514 }
2515 if (err_segs[i].rt_delay_ms != 0) {
2516 pr_cont("%s%ldms", firsttime ? "" : "+",
2517 err_segs[i].rt_delay_ms);
2518 firsttime = 0;
2519 }
2520 if (err_segs[i].rt_delay_us != 0) {
2521 pr_cont("%s%ldus", firsttime ? "" : "+",
2522 err_segs[i].rt_delay_us);
2523 firsttime = 0;
2524 }
2525 pr_cont("%s\n",
2526 err_segs[i].rt_preempted ? "preempted" : "");
2527
2528 }
2529 }
2530 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
2531 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
2532 else if (torture_onoff_failures())
2533 rcu_torture_print_module_parms(cur_ops,
2534 "End of test: RCU_HOTPLUG");
2535 else
2536 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
2537 torture_cleanup_end();
2538}
2539
2540#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
2541static void rcu_torture_leak_cb(struct rcu_head *rhp)
2542{
2543}
2544
2545static void rcu_torture_err_cb(struct rcu_head *rhp)
2546{
2547 /*
2548 * This -might- happen due to race conditions, but is unlikely.
2549 * The scenario that leads to this happening is that the
2550 * first of the pair of duplicate callbacks is queued,
2551 * someone else starts a grace period that includes that
2552 * callback, then the second of the pair must wait for the
2553 * next grace period. Unlikely, but can happen. If it
2554 * does happen, the debug-objects subsystem won't have splatted.
2555 */
2556 pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME);
2557}
2558#endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
2559
2560/*
2561 * Verify that double-free causes debug-objects to complain, but only
2562 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
2563 * cannot be carried out.
2564 */
2565static void rcu_test_debug_objects(void)
2566{
2567#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
2568 struct rcu_head rh1;
2569 struct rcu_head rh2;
2570
2571 init_rcu_head_on_stack(&rh1);
2572 init_rcu_head_on_stack(&rh2);
2573 pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME);
2574
2575 /* Try to queue the rh2 pair of callbacks for the same grace period. */
2576 preempt_disable(); /* Prevent preemption from interrupting test. */
2577 rcu_read_lock(); /* Make it impossible to finish a grace period. */
2578 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
2579 local_irq_disable(); /* Make it harder to start a new grace period. */
2580 call_rcu(&rh2, rcu_torture_leak_cb);
2581 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
2582 local_irq_enable();
2583 rcu_read_unlock();
2584 preempt_enable();
2585
2586 /* Wait for them all to get done so we can safely return. */
2587 rcu_barrier();
2588 pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME);
2589 destroy_rcu_head_on_stack(&rh1);
2590 destroy_rcu_head_on_stack(&rh2);
2591#else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
2592 pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME);
2593#endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
2594}
2595
2596static void rcutorture_sync(void)
2597{
2598 static unsigned long n;
2599
2600 if (cur_ops->sync && !(++n & 0xfff))
2601 cur_ops->sync();
2602}
2603
2604static int __init
2605rcu_torture_init(void)
2606{
2607 long i;
2608 int cpu;
2609 int firsterr = 0;
2610 static struct rcu_torture_ops *torture_ops[] = {
2611 &rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops,
2612 &busted_srcud_ops, &tasks_ops, &tasks_rude_ops,
2613 &tasks_tracing_ops, &trivial_ops,
2614 };
2615
2616 if (!torture_init_begin(torture_type, verbose))
2617 return -EBUSY;
2618
2619 /* Process args and tell the world that the torturer is on the job. */
2620 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
2621 cur_ops = torture_ops[i];
2622 if (strcmp(torture_type, cur_ops->name) == 0)
2623 break;
2624 }
2625 if (i == ARRAY_SIZE(torture_ops)) {
2626 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
2627 torture_type);
2628 pr_alert("rcu-torture types:");
2629 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
2630 pr_cont(" %s", torture_ops[i]->name);
2631 pr_cont("\n");
2632 WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST));
2633 firsterr = -EINVAL;
2634 cur_ops = NULL;
2635 goto unwind;
2636 }
2637 if (cur_ops->fqs == NULL && fqs_duration != 0) {
2638 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
2639 fqs_duration = 0;
2640 }
2641 if (cur_ops->init)
2642 cur_ops->init();
2643
2644 if (nreaders >= 0) {
2645 nrealreaders = nreaders;
2646 } else {
2647 nrealreaders = num_online_cpus() - 2 - nreaders;
2648 if (nrealreaders <= 0)
2649 nrealreaders = 1;
2650 }
2651 rcu_torture_print_module_parms(cur_ops, "Start of test");
2652
2653 /* Set up the freelist. */
2654
2655 INIT_LIST_HEAD(&rcu_torture_freelist);
2656 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
2657 rcu_tortures[i].rtort_mbtest = 0;
2658 list_add_tail(&rcu_tortures[i].rtort_free,
2659 &rcu_torture_freelist);
2660 }
2661
2662 /* Initialize the statistics so that each run gets its own numbers. */
2663
2664 rcu_torture_current = NULL;
2665 rcu_torture_current_version = 0;
2666 atomic_set(&n_rcu_torture_alloc, 0);
2667 atomic_set(&n_rcu_torture_alloc_fail, 0);
2668 atomic_set(&n_rcu_torture_free, 0);
2669 atomic_set(&n_rcu_torture_mberror, 0);
2670 atomic_set(&n_rcu_torture_error, 0);
2671 n_rcu_torture_barrier_error = 0;
2672 n_rcu_torture_boost_ktrerror = 0;
2673 n_rcu_torture_boost_rterror = 0;
2674 n_rcu_torture_boost_failure = 0;
2675 n_rcu_torture_boosts = 0;
2676 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
2677 atomic_set(&rcu_torture_wcount[i], 0);
2678 for_each_possible_cpu(cpu) {
2679 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
2680 per_cpu(rcu_torture_count, cpu)[i] = 0;
2681 per_cpu(rcu_torture_batch, cpu)[i] = 0;
2682 }
2683 }
2684 err_segs_recorded = 0;
2685 rt_read_nsegs = 0;
2686
2687 /* Start up the kthreads. */
2688
2689 firsterr = torture_create_kthread(rcu_torture_writer, NULL,
2690 writer_task);
2691 if (firsterr)
2692 goto unwind;
2693 if (nfakewriters > 0) {
2694 fakewriter_tasks = kcalloc(nfakewriters,
2695 sizeof(fakewriter_tasks[0]),
2696 GFP_KERNEL);
2697 if (fakewriter_tasks == NULL) {
2698 VERBOSE_TOROUT_ERRSTRING("out of memory");
2699 firsterr = -ENOMEM;
2700 goto unwind;
2701 }
2702 }
2703 for (i = 0; i < nfakewriters; i++) {
2704 firsterr = torture_create_kthread(rcu_torture_fakewriter,
2705 NULL, fakewriter_tasks[i]);
2706 if (firsterr)
2707 goto unwind;
2708 }
2709 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
2710 GFP_KERNEL);
2711 if (reader_tasks == NULL) {
2712 VERBOSE_TOROUT_ERRSTRING("out of memory");
2713 firsterr = -ENOMEM;
2714 goto unwind;
2715 }
2716 for (i = 0; i < nrealreaders; i++) {
2717 firsterr = torture_create_kthread(rcu_torture_reader, (void *)i,
2718 reader_tasks[i]);
2719 if (firsterr)
2720 goto unwind;
2721 }
2722 if (stat_interval > 0) {
2723 firsterr = torture_create_kthread(rcu_torture_stats, NULL,
2724 stats_task);
2725 if (firsterr)
2726 goto unwind;
2727 }
2728 if (test_no_idle_hz && shuffle_interval > 0) {
2729 firsterr = torture_shuffle_init(shuffle_interval * HZ);
2730 if (firsterr)
2731 goto unwind;
2732 }
2733 if (stutter < 0)
2734 stutter = 0;
2735 if (stutter) {
2736 int t;
2737
2738 t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ;
2739 firsterr = torture_stutter_init(stutter * HZ, t);
2740 if (firsterr)
2741 goto unwind;
2742 }
2743 if (fqs_duration < 0)
2744 fqs_duration = 0;
2745 if (fqs_duration) {
2746 /* Create the fqs thread */
2747 firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
2748 fqs_task);
2749 if (firsterr)
2750 goto unwind;
2751 }
2752 if (test_boost_interval < 1)
2753 test_boost_interval = 1;
2754 if (test_boost_duration < 2)
2755 test_boost_duration = 2;
2756 if (rcu_torture_can_boost()) {
2757
2758 boost_starttime = jiffies + test_boost_interval * HZ;
2759
2760 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE",
2761 rcutorture_booster_init,
2762 rcutorture_booster_cleanup);
2763 if (firsterr < 0)
2764 goto unwind;
2765 rcutor_hp = firsterr;
2766 }
2767 shutdown_jiffies = jiffies + shutdown_secs * HZ;
2768 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
2769 if (firsterr)
2770 goto unwind;
2771 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval,
2772 rcutorture_sync);
2773 if (firsterr)
2774 goto unwind;
2775 firsterr = rcu_torture_stall_init();
2776 if (firsterr)
2777 goto unwind;
2778 firsterr = rcu_torture_fwd_prog_init();
2779 if (firsterr)
2780 goto unwind;
2781 firsterr = rcu_torture_barrier_init();
2782 if (firsterr)
2783 goto unwind;
2784 firsterr = rcu_torture_read_exit_init();
2785 if (firsterr)
2786 goto unwind;
2787 if (object_debug)
2788 rcu_test_debug_objects();
2789 torture_init_end();
2790 return 0;
2791
2792unwind:
2793 torture_init_end();
2794 rcu_torture_cleanup();
2795 return firsterr;
2796}
2797
2798module_init(rcu_torture_init);
2799module_exit(rcu_torture_cleanup);
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Read-Copy Update module-based torture test facility
4 *
5 * Copyright (C) IBM Corporation, 2005, 2006
6 *
7 * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
8 * Josh Triplett <josh@joshtriplett.org>
9 *
10 * See also: Documentation/RCU/torture.txt
11 */
12
13#define pr_fmt(fmt) fmt
14
15#include <linux/types.h>
16#include <linux/kernel.h>
17#include <linux/init.h>
18#include <linux/module.h>
19#include <linux/kthread.h>
20#include <linux/err.h>
21#include <linux/spinlock.h>
22#include <linux/smp.h>
23#include <linux/rcupdate.h>
24#include <linux/interrupt.h>
25#include <linux/sched/signal.h>
26#include <uapi/linux/sched/types.h>
27#include <linux/atomic.h>
28#include <linux/bitops.h>
29#include <linux/completion.h>
30#include <linux/moduleparam.h>
31#include <linux/percpu.h>
32#include <linux/notifier.h>
33#include <linux/reboot.h>
34#include <linux/freezer.h>
35#include <linux/cpu.h>
36#include <linux/delay.h>
37#include <linux/stat.h>
38#include <linux/srcu.h>
39#include <linux/slab.h>
40#include <linux/trace_clock.h>
41#include <asm/byteorder.h>
42#include <linux/torture.h>
43#include <linux/vmalloc.h>
44#include <linux/sched/debug.h>
45#include <linux/sched/sysctl.h>
46#include <linux/oom.h>
47
48#include "rcu.h"
49
50MODULE_LICENSE("GPL");
51MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
52
53
54/* Bits for ->extendables field, extendables param, and related definitions. */
55#define RCUTORTURE_RDR_SHIFT 8 /* Put SRCU index in upper bits. */
56#define RCUTORTURE_RDR_MASK ((1 << RCUTORTURE_RDR_SHIFT) - 1)
57#define RCUTORTURE_RDR_BH 0x01 /* Extend readers by disabling bh. */
58#define RCUTORTURE_RDR_IRQ 0x02 /* ... disabling interrupts. */
59#define RCUTORTURE_RDR_PREEMPT 0x04 /* ... disabling preemption. */
60#define RCUTORTURE_RDR_RBH 0x08 /* ... rcu_read_lock_bh(). */
61#define RCUTORTURE_RDR_SCHED 0x10 /* ... rcu_read_lock_sched(). */
62#define RCUTORTURE_RDR_RCU 0x20 /* ... entering another RCU reader. */
63#define RCUTORTURE_RDR_NBITS 6 /* Number of bits defined above. */
64#define RCUTORTURE_MAX_EXTEND \
65 (RCUTORTURE_RDR_BH | RCUTORTURE_RDR_IRQ | RCUTORTURE_RDR_PREEMPT | \
66 RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED)
67#define RCUTORTURE_RDR_MAX_LOOPS 0x7 /* Maximum reader extensions. */
68 /* Must be power of two minus one. */
69#define RCUTORTURE_RDR_MAX_SEGS (RCUTORTURE_RDR_MAX_LOOPS + 3)
70
71torture_param(int, extendables, RCUTORTURE_MAX_EXTEND,
72 "Extend readers by disabling bh (1), irqs (2), or preempt (4)");
73torture_param(int, fqs_duration, 0,
74 "Duration of fqs bursts (us), 0 to disable");
75torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
76torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
77torture_param(bool, fwd_progress, 1, "Test grace-period forward progress");
78torture_param(int, fwd_progress_div, 4, "Fraction of CPU stall to wait");
79torture_param(int, fwd_progress_holdoff, 60,
80 "Time between forward-progress tests (s)");
81torture_param(bool, fwd_progress_need_resched, 1,
82 "Hide cond_resched() behind need_resched()");
83torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
84torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
85torture_param(bool, gp_normal, false,
86 "Use normal (non-expedited) GP wait primitives");
87torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
88torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
89torture_param(int, n_barrier_cbs, 0,
90 "# of callbacks/kthreads for barrier testing");
91torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
92torture_param(int, nreaders, -1, "Number of RCU reader threads");
93torture_param(int, object_debug, 0,
94 "Enable debug-object double call_rcu() testing");
95torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
96torture_param(int, onoff_interval, 0,
97 "Time between CPU hotplugs (jiffies), 0=disable");
98torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
99torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
100torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
101torture_param(int, stall_cpu_holdoff, 10,
102 "Time to wait before starting stall (s).");
103torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling.");
104torture_param(int, stat_interval, 60,
105 "Number of seconds between stats printk()s");
106torture_param(int, stutter, 5, "Number of seconds to run/halt test");
107torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
108torture_param(int, test_boost_duration, 4,
109 "Duration of each boost test, seconds.");
110torture_param(int, test_boost_interval, 7,
111 "Interval between boost tests, seconds.");
112torture_param(bool, test_no_idle_hz, true,
113 "Test support for tickless idle CPUs");
114torture_param(int, verbose, 1,
115 "Enable verbose debugging printk()s");
116
117static char *torture_type = "rcu";
118module_param(torture_type, charp, 0444);
119MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, srcu, ...)");
120
121static int nrealreaders;
122static struct task_struct *writer_task;
123static struct task_struct **fakewriter_tasks;
124static struct task_struct **reader_tasks;
125static struct task_struct *stats_task;
126static struct task_struct *fqs_task;
127static struct task_struct *boost_tasks[NR_CPUS];
128static struct task_struct *stall_task;
129static struct task_struct *fwd_prog_task;
130static struct task_struct **barrier_cbs_tasks;
131static struct task_struct *barrier_task;
132
133#define RCU_TORTURE_PIPE_LEN 10
134
135struct rcu_torture {
136 struct rcu_head rtort_rcu;
137 int rtort_pipe_count;
138 struct list_head rtort_free;
139 int rtort_mbtest;
140};
141
142static LIST_HEAD(rcu_torture_freelist);
143static struct rcu_torture __rcu *rcu_torture_current;
144static unsigned long rcu_torture_current_version;
145static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
146static DEFINE_SPINLOCK(rcu_torture_lock);
147static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count);
148static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch);
149static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
150static atomic_t n_rcu_torture_alloc;
151static atomic_t n_rcu_torture_alloc_fail;
152static atomic_t n_rcu_torture_free;
153static atomic_t n_rcu_torture_mberror;
154static atomic_t n_rcu_torture_error;
155static long n_rcu_torture_barrier_error;
156static long n_rcu_torture_boost_ktrerror;
157static long n_rcu_torture_boost_rterror;
158static long n_rcu_torture_boost_failure;
159static long n_rcu_torture_boosts;
160static atomic_long_t n_rcu_torture_timers;
161static long n_barrier_attempts;
162static long n_barrier_successes; /* did rcu_barrier test succeed? */
163static struct list_head rcu_torture_removed;
164static unsigned long shutdown_jiffies;
165
166static int rcu_torture_writer_state;
167#define RTWS_FIXED_DELAY 0
168#define RTWS_DELAY 1
169#define RTWS_REPLACE 2
170#define RTWS_DEF_FREE 3
171#define RTWS_EXP_SYNC 4
172#define RTWS_COND_GET 5
173#define RTWS_COND_SYNC 6
174#define RTWS_SYNC 7
175#define RTWS_STUTTER 8
176#define RTWS_STOPPING 9
177static const char * const rcu_torture_writer_state_names[] = {
178 "RTWS_FIXED_DELAY",
179 "RTWS_DELAY",
180 "RTWS_REPLACE",
181 "RTWS_DEF_FREE",
182 "RTWS_EXP_SYNC",
183 "RTWS_COND_GET",
184 "RTWS_COND_SYNC",
185 "RTWS_SYNC",
186 "RTWS_STUTTER",
187 "RTWS_STOPPING",
188};
189
190/* Record reader segment types and duration for first failing read. */
191struct rt_read_seg {
192 int rt_readstate;
193 unsigned long rt_delay_jiffies;
194 unsigned long rt_delay_ms;
195 unsigned long rt_delay_us;
196 bool rt_preempted;
197};
198static int err_segs_recorded;
199static struct rt_read_seg err_segs[RCUTORTURE_RDR_MAX_SEGS];
200static int rt_read_nsegs;
201
202static const char *rcu_torture_writer_state_getname(void)
203{
204 unsigned int i = READ_ONCE(rcu_torture_writer_state);
205
206 if (i >= ARRAY_SIZE(rcu_torture_writer_state_names))
207 return "???";
208 return rcu_torture_writer_state_names[i];
209}
210
211#if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
212#define rcu_can_boost() 1
213#else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
214#define rcu_can_boost() 0
215#endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
216
217#ifdef CONFIG_RCU_TRACE
218static u64 notrace rcu_trace_clock_local(void)
219{
220 u64 ts = trace_clock_local();
221
222 (void)do_div(ts, NSEC_PER_USEC);
223 return ts;
224}
225#else /* #ifdef CONFIG_RCU_TRACE */
226static u64 notrace rcu_trace_clock_local(void)
227{
228 return 0ULL;
229}
230#endif /* #else #ifdef CONFIG_RCU_TRACE */
231
232/*
233 * Stop aggressive CPU-hog tests a bit before the end of the test in order
234 * to avoid interfering with test shutdown.
235 */
236static bool shutdown_time_arrived(void)
237{
238 return shutdown_secs && time_after(jiffies, shutdown_jiffies - 30 * HZ);
239}
240
241static unsigned long boost_starttime; /* jiffies of next boost test start. */
242static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
243 /* and boost task create/destroy. */
244static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
245static bool barrier_phase; /* Test phase. */
246static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
247static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
248static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
249
250static bool rcu_fwd_cb_nodelay; /* Short rcu_torture_delay() delays. */
251
252/*
253 * Allocate an element from the rcu_tortures pool.
254 */
255static struct rcu_torture *
256rcu_torture_alloc(void)
257{
258 struct list_head *p;
259
260 spin_lock_bh(&rcu_torture_lock);
261 if (list_empty(&rcu_torture_freelist)) {
262 atomic_inc(&n_rcu_torture_alloc_fail);
263 spin_unlock_bh(&rcu_torture_lock);
264 return NULL;
265 }
266 atomic_inc(&n_rcu_torture_alloc);
267 p = rcu_torture_freelist.next;
268 list_del_init(p);
269 spin_unlock_bh(&rcu_torture_lock);
270 return container_of(p, struct rcu_torture, rtort_free);
271}
272
273/*
274 * Free an element to the rcu_tortures pool.
275 */
276static void
277rcu_torture_free(struct rcu_torture *p)
278{
279 atomic_inc(&n_rcu_torture_free);
280 spin_lock_bh(&rcu_torture_lock);
281 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
282 spin_unlock_bh(&rcu_torture_lock);
283}
284
285/*
286 * Operations vector for selecting different types of tests.
287 */
288
289struct rcu_torture_ops {
290 int ttype;
291 void (*init)(void);
292 void (*cleanup)(void);
293 int (*readlock)(void);
294 void (*read_delay)(struct torture_random_state *rrsp,
295 struct rt_read_seg *rtrsp);
296 void (*readunlock)(int idx);
297 unsigned long (*get_gp_seq)(void);
298 unsigned long (*gp_diff)(unsigned long new, unsigned long old);
299 void (*deferred_free)(struct rcu_torture *p);
300 void (*sync)(void);
301 void (*exp_sync)(void);
302 unsigned long (*get_state)(void);
303 void (*cond_sync)(unsigned long oldstate);
304 call_rcu_func_t call;
305 void (*cb_barrier)(void);
306 void (*fqs)(void);
307 void (*stats)(void);
308 int (*stall_dur)(void);
309 int irq_capable;
310 int can_boost;
311 int extendables;
312 int slow_gps;
313 const char *name;
314};
315
316static struct rcu_torture_ops *cur_ops;
317
318/*
319 * Definitions for rcu torture testing.
320 */
321
322static int rcu_torture_read_lock(void) __acquires(RCU)
323{
324 rcu_read_lock();
325 return 0;
326}
327
328static void
329rcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
330{
331 unsigned long started;
332 unsigned long completed;
333 const unsigned long shortdelay_us = 200;
334 unsigned long longdelay_ms = 300;
335 unsigned long long ts;
336
337 /* We want a short delay sometimes to make a reader delay the grace
338 * period, and we want a long delay occasionally to trigger
339 * force_quiescent_state. */
340
341 if (!rcu_fwd_cb_nodelay &&
342 !(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) {
343 started = cur_ops->get_gp_seq();
344 ts = rcu_trace_clock_local();
345 if (preempt_count() & (SOFTIRQ_MASK | HARDIRQ_MASK))
346 longdelay_ms = 5; /* Avoid triggering BH limits. */
347 mdelay(longdelay_ms);
348 rtrsp->rt_delay_ms = longdelay_ms;
349 completed = cur_ops->get_gp_seq();
350 do_trace_rcu_torture_read(cur_ops->name, NULL, ts,
351 started, completed);
352 }
353 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) {
354 udelay(shortdelay_us);
355 rtrsp->rt_delay_us = shortdelay_us;
356 }
357 if (!preempt_count() &&
358 !(torture_random(rrsp) % (nrealreaders * 500))) {
359 torture_preempt_schedule(); /* QS only if preemptible. */
360 rtrsp->rt_preempted = true;
361 }
362}
363
364static void rcu_torture_read_unlock(int idx) __releases(RCU)
365{
366 rcu_read_unlock();
367}
368
369/*
370 * Update callback in the pipe. This should be invoked after a grace period.
371 */
372static bool
373rcu_torture_pipe_update_one(struct rcu_torture *rp)
374{
375 int i;
376
377 i = rp->rtort_pipe_count;
378 if (i > RCU_TORTURE_PIPE_LEN)
379 i = RCU_TORTURE_PIPE_LEN;
380 atomic_inc(&rcu_torture_wcount[i]);
381 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
382 rp->rtort_mbtest = 0;
383 return true;
384 }
385 return false;
386}
387
388/*
389 * Update all callbacks in the pipe. Suitable for synchronous grace-period
390 * primitives.
391 */
392static void
393rcu_torture_pipe_update(struct rcu_torture *old_rp)
394{
395 struct rcu_torture *rp;
396 struct rcu_torture *rp1;
397
398 if (old_rp)
399 list_add(&old_rp->rtort_free, &rcu_torture_removed);
400 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
401 if (rcu_torture_pipe_update_one(rp)) {
402 list_del(&rp->rtort_free);
403 rcu_torture_free(rp);
404 }
405 }
406}
407
408static void
409rcu_torture_cb(struct rcu_head *p)
410{
411 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
412
413 if (torture_must_stop_irq()) {
414 /* Test is ending, just drop callbacks on the floor. */
415 /* The next initialization will pick up the pieces. */
416 return;
417 }
418 if (rcu_torture_pipe_update_one(rp))
419 rcu_torture_free(rp);
420 else
421 cur_ops->deferred_free(rp);
422}
423
424static unsigned long rcu_no_completed(void)
425{
426 return 0;
427}
428
429static void rcu_torture_deferred_free(struct rcu_torture *p)
430{
431 call_rcu(&p->rtort_rcu, rcu_torture_cb);
432}
433
434static void rcu_sync_torture_init(void)
435{
436 INIT_LIST_HEAD(&rcu_torture_removed);
437}
438
439static struct rcu_torture_ops rcu_ops = {
440 .ttype = RCU_FLAVOR,
441 .init = rcu_sync_torture_init,
442 .readlock = rcu_torture_read_lock,
443 .read_delay = rcu_read_delay,
444 .readunlock = rcu_torture_read_unlock,
445 .get_gp_seq = rcu_get_gp_seq,
446 .gp_diff = rcu_seq_diff,
447 .deferred_free = rcu_torture_deferred_free,
448 .sync = synchronize_rcu,
449 .exp_sync = synchronize_rcu_expedited,
450 .get_state = get_state_synchronize_rcu,
451 .cond_sync = cond_synchronize_rcu,
452 .call = call_rcu,
453 .cb_barrier = rcu_barrier,
454 .fqs = rcu_force_quiescent_state,
455 .stats = NULL,
456 .stall_dur = rcu_jiffies_till_stall_check,
457 .irq_capable = 1,
458 .can_boost = rcu_can_boost(),
459 .extendables = RCUTORTURE_MAX_EXTEND,
460 .name = "rcu"
461};
462
463/*
464 * Don't even think about trying any of these in real life!!!
465 * The names includes "busted", and they really means it!
466 * The only purpose of these functions is to provide a buggy RCU
467 * implementation to make sure that rcutorture correctly emits
468 * buggy-RCU error messages.
469 */
470static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
471{
472 /* This is a deliberate bug for testing purposes only! */
473 rcu_torture_cb(&p->rtort_rcu);
474}
475
476static void synchronize_rcu_busted(void)
477{
478 /* This is a deliberate bug for testing purposes only! */
479}
480
481static void
482call_rcu_busted(struct rcu_head *head, rcu_callback_t func)
483{
484 /* This is a deliberate bug for testing purposes only! */
485 func(head);
486}
487
488static struct rcu_torture_ops rcu_busted_ops = {
489 .ttype = INVALID_RCU_FLAVOR,
490 .init = rcu_sync_torture_init,
491 .readlock = rcu_torture_read_lock,
492 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
493 .readunlock = rcu_torture_read_unlock,
494 .get_gp_seq = rcu_no_completed,
495 .deferred_free = rcu_busted_torture_deferred_free,
496 .sync = synchronize_rcu_busted,
497 .exp_sync = synchronize_rcu_busted,
498 .call = call_rcu_busted,
499 .cb_barrier = NULL,
500 .fqs = NULL,
501 .stats = NULL,
502 .irq_capable = 1,
503 .name = "busted"
504};
505
506/*
507 * Definitions for srcu torture testing.
508 */
509
510DEFINE_STATIC_SRCU(srcu_ctl);
511static struct srcu_struct srcu_ctld;
512static struct srcu_struct *srcu_ctlp = &srcu_ctl;
513
514static int srcu_torture_read_lock(void) __acquires(srcu_ctlp)
515{
516 return srcu_read_lock(srcu_ctlp);
517}
518
519static void
520srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
521{
522 long delay;
523 const long uspertick = 1000000 / HZ;
524 const long longdelay = 10;
525
526 /* We want there to be long-running readers, but not all the time. */
527
528 delay = torture_random(rrsp) %
529 (nrealreaders * 2 * longdelay * uspertick);
530 if (!delay && in_task()) {
531 schedule_timeout_interruptible(longdelay);
532 rtrsp->rt_delay_jiffies = longdelay;
533 } else {
534 rcu_read_delay(rrsp, rtrsp);
535 }
536}
537
538static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp)
539{
540 srcu_read_unlock(srcu_ctlp, idx);
541}
542
543static unsigned long srcu_torture_completed(void)
544{
545 return srcu_batches_completed(srcu_ctlp);
546}
547
548static void srcu_torture_deferred_free(struct rcu_torture *rp)
549{
550 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
551}
552
553static void srcu_torture_synchronize(void)
554{
555 synchronize_srcu(srcu_ctlp);
556}
557
558static void srcu_torture_call(struct rcu_head *head,
559 rcu_callback_t func)
560{
561 call_srcu(srcu_ctlp, head, func);
562}
563
564static void srcu_torture_barrier(void)
565{
566 srcu_barrier(srcu_ctlp);
567}
568
569static void srcu_torture_stats(void)
570{
571 srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG);
572}
573
574static void srcu_torture_synchronize_expedited(void)
575{
576 synchronize_srcu_expedited(srcu_ctlp);
577}
578
579static struct rcu_torture_ops srcu_ops = {
580 .ttype = SRCU_FLAVOR,
581 .init = rcu_sync_torture_init,
582 .readlock = srcu_torture_read_lock,
583 .read_delay = srcu_read_delay,
584 .readunlock = srcu_torture_read_unlock,
585 .get_gp_seq = srcu_torture_completed,
586 .deferred_free = srcu_torture_deferred_free,
587 .sync = srcu_torture_synchronize,
588 .exp_sync = srcu_torture_synchronize_expedited,
589 .call = srcu_torture_call,
590 .cb_barrier = srcu_torture_barrier,
591 .stats = srcu_torture_stats,
592 .irq_capable = 1,
593 .name = "srcu"
594};
595
596static void srcu_torture_init(void)
597{
598 rcu_sync_torture_init();
599 WARN_ON(init_srcu_struct(&srcu_ctld));
600 srcu_ctlp = &srcu_ctld;
601}
602
603static void srcu_torture_cleanup(void)
604{
605 cleanup_srcu_struct(&srcu_ctld);
606 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
607}
608
609/* As above, but dynamically allocated. */
610static struct rcu_torture_ops srcud_ops = {
611 .ttype = SRCU_FLAVOR,
612 .init = srcu_torture_init,
613 .cleanup = srcu_torture_cleanup,
614 .readlock = srcu_torture_read_lock,
615 .read_delay = srcu_read_delay,
616 .readunlock = srcu_torture_read_unlock,
617 .get_gp_seq = srcu_torture_completed,
618 .deferred_free = srcu_torture_deferred_free,
619 .sync = srcu_torture_synchronize,
620 .exp_sync = srcu_torture_synchronize_expedited,
621 .call = srcu_torture_call,
622 .cb_barrier = srcu_torture_barrier,
623 .stats = srcu_torture_stats,
624 .irq_capable = 1,
625 .name = "srcud"
626};
627
628/* As above, but broken due to inappropriate reader extension. */
629static struct rcu_torture_ops busted_srcud_ops = {
630 .ttype = SRCU_FLAVOR,
631 .init = srcu_torture_init,
632 .cleanup = srcu_torture_cleanup,
633 .readlock = srcu_torture_read_lock,
634 .read_delay = rcu_read_delay,
635 .readunlock = srcu_torture_read_unlock,
636 .get_gp_seq = srcu_torture_completed,
637 .deferred_free = srcu_torture_deferred_free,
638 .sync = srcu_torture_synchronize,
639 .exp_sync = srcu_torture_synchronize_expedited,
640 .call = srcu_torture_call,
641 .cb_barrier = srcu_torture_barrier,
642 .stats = srcu_torture_stats,
643 .irq_capable = 1,
644 .extendables = RCUTORTURE_MAX_EXTEND,
645 .name = "busted_srcud"
646};
647
648/*
649 * Definitions for RCU-tasks torture testing.
650 */
651
652static int tasks_torture_read_lock(void)
653{
654 return 0;
655}
656
657static void tasks_torture_read_unlock(int idx)
658{
659}
660
661static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
662{
663 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
664}
665
666static struct rcu_torture_ops tasks_ops = {
667 .ttype = RCU_TASKS_FLAVOR,
668 .init = rcu_sync_torture_init,
669 .readlock = tasks_torture_read_lock,
670 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
671 .readunlock = tasks_torture_read_unlock,
672 .get_gp_seq = rcu_no_completed,
673 .deferred_free = rcu_tasks_torture_deferred_free,
674 .sync = synchronize_rcu_tasks,
675 .exp_sync = synchronize_rcu_tasks,
676 .call = call_rcu_tasks,
677 .cb_barrier = rcu_barrier_tasks,
678 .fqs = NULL,
679 .stats = NULL,
680 .irq_capable = 1,
681 .slow_gps = 1,
682 .name = "tasks"
683};
684
685/*
686 * Definitions for trivial CONFIG_PREEMPT=n-only torture testing.
687 * This implementation does not necessarily work well with CPU hotplug.
688 */
689
690static void synchronize_rcu_trivial(void)
691{
692 int cpu;
693
694 for_each_online_cpu(cpu) {
695 rcutorture_sched_setaffinity(current->pid, cpumask_of(cpu));
696 WARN_ON_ONCE(raw_smp_processor_id() != cpu);
697 }
698}
699
700static int rcu_torture_read_lock_trivial(void) __acquires(RCU)
701{
702 preempt_disable();
703 return 0;
704}
705
706static void rcu_torture_read_unlock_trivial(int idx) __releases(RCU)
707{
708 preempt_enable();
709}
710
711static struct rcu_torture_ops trivial_ops = {
712 .ttype = RCU_TRIVIAL_FLAVOR,
713 .init = rcu_sync_torture_init,
714 .readlock = rcu_torture_read_lock_trivial,
715 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
716 .readunlock = rcu_torture_read_unlock_trivial,
717 .get_gp_seq = rcu_no_completed,
718 .sync = synchronize_rcu_trivial,
719 .exp_sync = synchronize_rcu_trivial,
720 .fqs = NULL,
721 .stats = NULL,
722 .irq_capable = 1,
723 .name = "trivial"
724};
725
726static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old)
727{
728 if (!cur_ops->gp_diff)
729 return new - old;
730 return cur_ops->gp_diff(new, old);
731}
732
733static bool __maybe_unused torturing_tasks(void)
734{
735 return cur_ops == &tasks_ops;
736}
737
738/*
739 * RCU torture priority-boost testing. Runs one real-time thread per
740 * CPU for moderate bursts, repeatedly registering RCU callbacks and
741 * spinning waiting for them to be invoked. If a given callback takes
742 * too long to be invoked, we assume that priority inversion has occurred.
743 */
744
745struct rcu_boost_inflight {
746 struct rcu_head rcu;
747 int inflight;
748};
749
750static void rcu_torture_boost_cb(struct rcu_head *head)
751{
752 struct rcu_boost_inflight *rbip =
753 container_of(head, struct rcu_boost_inflight, rcu);
754
755 /* Ensure RCU-core accesses precede clearing ->inflight */
756 smp_store_release(&rbip->inflight, 0);
757}
758
759static int old_rt_runtime = -1;
760
761static void rcu_torture_disable_rt_throttle(void)
762{
763 /*
764 * Disable RT throttling so that rcutorture's boost threads don't get
765 * throttled. Only possible if rcutorture is built-in otherwise the
766 * user should manually do this by setting the sched_rt_period_us and
767 * sched_rt_runtime sysctls.
768 */
769 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime != -1)
770 return;
771
772 old_rt_runtime = sysctl_sched_rt_runtime;
773 sysctl_sched_rt_runtime = -1;
774}
775
776static void rcu_torture_enable_rt_throttle(void)
777{
778 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime == -1)
779 return;
780
781 sysctl_sched_rt_runtime = old_rt_runtime;
782 old_rt_runtime = -1;
783}
784
785static bool rcu_torture_boost_failed(unsigned long start, unsigned long end)
786{
787 if (end - start > test_boost_duration * HZ - HZ / 2) {
788 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
789 n_rcu_torture_boost_failure++;
790
791 return true; /* failed */
792 }
793
794 return false; /* passed */
795}
796
797static int rcu_torture_boost(void *arg)
798{
799 unsigned long call_rcu_time;
800 unsigned long endtime;
801 unsigned long oldstarttime;
802 struct rcu_boost_inflight rbi = { .inflight = 0 };
803 struct sched_param sp;
804
805 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
806
807 /* Set real-time priority. */
808 sp.sched_priority = 1;
809 if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
810 VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!");
811 n_rcu_torture_boost_rterror++;
812 }
813
814 init_rcu_head_on_stack(&rbi.rcu);
815 /* Each pass through the following loop does one boost-test cycle. */
816 do {
817 /* Track if the test failed already in this test interval? */
818 bool failed = false;
819
820 /* Increment n_rcu_torture_boosts once per boost-test */
821 while (!kthread_should_stop()) {
822 if (mutex_trylock(&boost_mutex)) {
823 n_rcu_torture_boosts++;
824 mutex_unlock(&boost_mutex);
825 break;
826 }
827 schedule_timeout_uninterruptible(1);
828 }
829 if (kthread_should_stop())
830 goto checkwait;
831
832 /* Wait for the next test interval. */
833 oldstarttime = boost_starttime;
834 while (ULONG_CMP_LT(jiffies, oldstarttime)) {
835 schedule_timeout_interruptible(oldstarttime - jiffies);
836 stutter_wait("rcu_torture_boost");
837 if (torture_must_stop())
838 goto checkwait;
839 }
840
841 /* Do one boost-test interval. */
842 endtime = oldstarttime + test_boost_duration * HZ;
843 call_rcu_time = jiffies;
844 while (ULONG_CMP_LT(jiffies, endtime)) {
845 /* If we don't have a callback in flight, post one. */
846 if (!smp_load_acquire(&rbi.inflight)) {
847 /* RCU core before ->inflight = 1. */
848 smp_store_release(&rbi.inflight, 1);
849 call_rcu(&rbi.rcu, rcu_torture_boost_cb);
850 /* Check if the boost test failed */
851 failed = failed ||
852 rcu_torture_boost_failed(call_rcu_time,
853 jiffies);
854 call_rcu_time = jiffies;
855 }
856 stutter_wait("rcu_torture_boost");
857 if (torture_must_stop())
858 goto checkwait;
859 }
860
861 /*
862 * If boost never happened, then inflight will always be 1, in
863 * this case the boost check would never happen in the above
864 * loop so do another one here.
865 */
866 if (!failed && smp_load_acquire(&rbi.inflight))
867 rcu_torture_boost_failed(call_rcu_time, jiffies);
868
869 /*
870 * Set the start time of the next test interval.
871 * Yes, this is vulnerable to long delays, but such
872 * delays simply cause a false negative for the next
873 * interval. Besides, we are running at RT priority,
874 * so delays should be relatively rare.
875 */
876 while (oldstarttime == boost_starttime &&
877 !kthread_should_stop()) {
878 if (mutex_trylock(&boost_mutex)) {
879 boost_starttime = jiffies +
880 test_boost_interval * HZ;
881 mutex_unlock(&boost_mutex);
882 break;
883 }
884 schedule_timeout_uninterruptible(1);
885 }
886
887 /* Go do the stutter. */
888checkwait: stutter_wait("rcu_torture_boost");
889 } while (!torture_must_stop());
890
891 /* Clean up and exit. */
892 while (!kthread_should_stop() || smp_load_acquire(&rbi.inflight)) {
893 torture_shutdown_absorb("rcu_torture_boost");
894 schedule_timeout_uninterruptible(1);
895 }
896 destroy_rcu_head_on_stack(&rbi.rcu);
897 torture_kthread_stopping("rcu_torture_boost");
898 return 0;
899}
900
901/*
902 * RCU torture force-quiescent-state kthread. Repeatedly induces
903 * bursts of calls to force_quiescent_state(), increasing the probability
904 * of occurrence of some important types of race conditions.
905 */
906static int
907rcu_torture_fqs(void *arg)
908{
909 unsigned long fqs_resume_time;
910 int fqs_burst_remaining;
911
912 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
913 do {
914 fqs_resume_time = jiffies + fqs_stutter * HZ;
915 while (ULONG_CMP_LT(jiffies, fqs_resume_time) &&
916 !kthread_should_stop()) {
917 schedule_timeout_interruptible(1);
918 }
919 fqs_burst_remaining = fqs_duration;
920 while (fqs_burst_remaining > 0 &&
921 !kthread_should_stop()) {
922 cur_ops->fqs();
923 udelay(fqs_holdoff);
924 fqs_burst_remaining -= fqs_holdoff;
925 }
926 stutter_wait("rcu_torture_fqs");
927 } while (!torture_must_stop());
928 torture_kthread_stopping("rcu_torture_fqs");
929 return 0;
930}
931
932/*
933 * RCU torture writer kthread. Repeatedly substitutes a new structure
934 * for that pointed to by rcu_torture_current, freeing the old structure
935 * after a series of grace periods (the "pipeline").
936 */
937static int
938rcu_torture_writer(void *arg)
939{
940 bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
941 int expediting = 0;
942 unsigned long gp_snap;
943 bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal;
944 bool gp_sync1 = gp_sync;
945 int i;
946 struct rcu_torture *rp;
947 struct rcu_torture *old_rp;
948 static DEFINE_TORTURE_RANDOM(rand);
949 int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC,
950 RTWS_COND_GET, RTWS_SYNC };
951 int nsynctypes = 0;
952
953 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
954 if (!can_expedite)
955 pr_alert("%s" TORTURE_FLAG
956 " GP expediting controlled from boot/sysfs for %s.\n",
957 torture_type, cur_ops->name);
958
959 /* Initialize synctype[] array. If none set, take default. */
960 if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync1)
961 gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true;
962 if (gp_cond1 && cur_ops->get_state && cur_ops->cond_sync) {
963 synctype[nsynctypes++] = RTWS_COND_GET;
964 pr_info("%s: Testing conditional GPs.\n", __func__);
965 } else if (gp_cond && (!cur_ops->get_state || !cur_ops->cond_sync)) {
966 pr_alert("%s: gp_cond without primitives.\n", __func__);
967 }
968 if (gp_exp1 && cur_ops->exp_sync) {
969 synctype[nsynctypes++] = RTWS_EXP_SYNC;
970 pr_info("%s: Testing expedited GPs.\n", __func__);
971 } else if (gp_exp && !cur_ops->exp_sync) {
972 pr_alert("%s: gp_exp without primitives.\n", __func__);
973 }
974 if (gp_normal1 && cur_ops->deferred_free) {
975 synctype[nsynctypes++] = RTWS_DEF_FREE;
976 pr_info("%s: Testing asynchronous GPs.\n", __func__);
977 } else if (gp_normal && !cur_ops->deferred_free) {
978 pr_alert("%s: gp_normal without primitives.\n", __func__);
979 }
980 if (gp_sync1 && cur_ops->sync) {
981 synctype[nsynctypes++] = RTWS_SYNC;
982 pr_info("%s: Testing normal GPs.\n", __func__);
983 } else if (gp_sync && !cur_ops->sync) {
984 pr_alert("%s: gp_sync without primitives.\n", __func__);
985 }
986 if (WARN_ONCE(nsynctypes == 0,
987 "rcu_torture_writer: No update-side primitives.\n")) {
988 /*
989 * No updates primitives, so don't try updating.
990 * The resulting test won't be testing much, hence the
991 * above WARN_ONCE().
992 */
993 rcu_torture_writer_state = RTWS_STOPPING;
994 torture_kthread_stopping("rcu_torture_writer");
995 }
996
997 do {
998 rcu_torture_writer_state = RTWS_FIXED_DELAY;
999 schedule_timeout_uninterruptible(1);
1000 rp = rcu_torture_alloc();
1001 if (rp == NULL)
1002 continue;
1003 rp->rtort_pipe_count = 0;
1004 rcu_torture_writer_state = RTWS_DELAY;
1005 udelay(torture_random(&rand) & 0x3ff);
1006 rcu_torture_writer_state = RTWS_REPLACE;
1007 old_rp = rcu_dereference_check(rcu_torture_current,
1008 current == writer_task);
1009 rp->rtort_mbtest = 1;
1010 rcu_assign_pointer(rcu_torture_current, rp);
1011 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
1012 if (old_rp) {
1013 i = old_rp->rtort_pipe_count;
1014 if (i > RCU_TORTURE_PIPE_LEN)
1015 i = RCU_TORTURE_PIPE_LEN;
1016 atomic_inc(&rcu_torture_wcount[i]);
1017 old_rp->rtort_pipe_count++;
1018 switch (synctype[torture_random(&rand) % nsynctypes]) {
1019 case RTWS_DEF_FREE:
1020 rcu_torture_writer_state = RTWS_DEF_FREE;
1021 cur_ops->deferred_free(old_rp);
1022 break;
1023 case RTWS_EXP_SYNC:
1024 rcu_torture_writer_state = RTWS_EXP_SYNC;
1025 cur_ops->exp_sync();
1026 rcu_torture_pipe_update(old_rp);
1027 break;
1028 case RTWS_COND_GET:
1029 rcu_torture_writer_state = RTWS_COND_GET;
1030 gp_snap = cur_ops->get_state();
1031 i = torture_random(&rand) % 16;
1032 if (i != 0)
1033 schedule_timeout_interruptible(i);
1034 udelay(torture_random(&rand) % 1000);
1035 rcu_torture_writer_state = RTWS_COND_SYNC;
1036 cur_ops->cond_sync(gp_snap);
1037 rcu_torture_pipe_update(old_rp);
1038 break;
1039 case RTWS_SYNC:
1040 rcu_torture_writer_state = RTWS_SYNC;
1041 cur_ops->sync();
1042 rcu_torture_pipe_update(old_rp);
1043 break;
1044 default:
1045 WARN_ON_ONCE(1);
1046 break;
1047 }
1048 }
1049 WRITE_ONCE(rcu_torture_current_version,
1050 rcu_torture_current_version + 1);
1051 /* Cycle through nesting levels of rcu_expedite_gp() calls. */
1052 if (can_expedite &&
1053 !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
1054 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
1055 if (expediting >= 0)
1056 rcu_expedite_gp();
1057 else
1058 rcu_unexpedite_gp();
1059 if (++expediting > 3)
1060 expediting = -expediting;
1061 } else if (!can_expedite) { /* Disabled during boot, recheck. */
1062 can_expedite = !rcu_gp_is_expedited() &&
1063 !rcu_gp_is_normal();
1064 }
1065 rcu_torture_writer_state = RTWS_STUTTER;
1066 if (stutter_wait("rcu_torture_writer") &&
1067 !READ_ONCE(rcu_fwd_cb_nodelay) &&
1068 !cur_ops->slow_gps &&
1069 !torture_must_stop())
1070 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++)
1071 if (list_empty(&rcu_tortures[i].rtort_free) &&
1072 rcu_access_pointer(rcu_torture_current) !=
1073 &rcu_tortures[i]) {
1074 rcu_ftrace_dump(DUMP_ALL);
1075 WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count);
1076 }
1077 } while (!torture_must_stop());
1078 /* Reset expediting back to unexpedited. */
1079 if (expediting > 0)
1080 expediting = -expediting;
1081 while (can_expedite && expediting++ < 0)
1082 rcu_unexpedite_gp();
1083 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
1084 if (!can_expedite)
1085 pr_alert("%s" TORTURE_FLAG
1086 " Dynamic grace-period expediting was disabled.\n",
1087 torture_type);
1088 rcu_torture_writer_state = RTWS_STOPPING;
1089 torture_kthread_stopping("rcu_torture_writer");
1090 return 0;
1091}
1092
1093/*
1094 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
1095 * delay between calls.
1096 */
1097static int
1098rcu_torture_fakewriter(void *arg)
1099{
1100 DEFINE_TORTURE_RANDOM(rand);
1101
1102 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1103 set_user_nice(current, MAX_NICE);
1104
1105 do {
1106 schedule_timeout_uninterruptible(1 + torture_random(&rand)%10);
1107 udelay(torture_random(&rand) & 0x3ff);
1108 if (cur_ops->cb_barrier != NULL &&
1109 torture_random(&rand) % (nfakewriters * 8) == 0) {
1110 cur_ops->cb_barrier();
1111 } else if (gp_normal == gp_exp) {
1112 if (cur_ops->sync && torture_random(&rand) & 0x80)
1113 cur_ops->sync();
1114 else if (cur_ops->exp_sync)
1115 cur_ops->exp_sync();
1116 } else if (gp_normal && cur_ops->sync) {
1117 cur_ops->sync();
1118 } else if (cur_ops->exp_sync) {
1119 cur_ops->exp_sync();
1120 }
1121 stutter_wait("rcu_torture_fakewriter");
1122 } while (!torture_must_stop());
1123
1124 torture_kthread_stopping("rcu_torture_fakewriter");
1125 return 0;
1126}
1127
1128static void rcu_torture_timer_cb(struct rcu_head *rhp)
1129{
1130 kfree(rhp);
1131}
1132
1133/*
1134 * Do one extension of an RCU read-side critical section using the
1135 * current reader state in readstate (set to zero for initial entry
1136 * to extended critical section), set the new state as specified by
1137 * newstate (set to zero for final exit from extended critical section),
1138 * and random-number-generator state in trsp. If this is neither the
1139 * beginning or end of the critical section and if there was actually a
1140 * change, do a ->read_delay().
1141 */
1142static void rcutorture_one_extend(int *readstate, int newstate,
1143 struct torture_random_state *trsp,
1144 struct rt_read_seg *rtrsp)
1145{
1146 int idxnew = -1;
1147 int idxold = *readstate;
1148 int statesnew = ~*readstate & newstate;
1149 int statesold = *readstate & ~newstate;
1150
1151 WARN_ON_ONCE(idxold < 0);
1152 WARN_ON_ONCE((idxold >> RCUTORTURE_RDR_SHIFT) > 1);
1153 rtrsp->rt_readstate = newstate;
1154
1155 /* First, put new protection in place to avoid critical-section gap. */
1156 if (statesnew & RCUTORTURE_RDR_BH)
1157 local_bh_disable();
1158 if (statesnew & RCUTORTURE_RDR_IRQ)
1159 local_irq_disable();
1160 if (statesnew & RCUTORTURE_RDR_PREEMPT)
1161 preempt_disable();
1162 if (statesnew & RCUTORTURE_RDR_RBH)
1163 rcu_read_lock_bh();
1164 if (statesnew & RCUTORTURE_RDR_SCHED)
1165 rcu_read_lock_sched();
1166 if (statesnew & RCUTORTURE_RDR_RCU)
1167 idxnew = cur_ops->readlock() << RCUTORTURE_RDR_SHIFT;
1168
1169 /* Next, remove old protection, irq first due to bh conflict. */
1170 if (statesold & RCUTORTURE_RDR_IRQ)
1171 local_irq_enable();
1172 if (statesold & RCUTORTURE_RDR_BH)
1173 local_bh_enable();
1174 if (statesold & RCUTORTURE_RDR_PREEMPT)
1175 preempt_enable();
1176 if (statesold & RCUTORTURE_RDR_RBH)
1177 rcu_read_unlock_bh();
1178 if (statesold & RCUTORTURE_RDR_SCHED)
1179 rcu_read_unlock_sched();
1180 if (statesold & RCUTORTURE_RDR_RCU)
1181 cur_ops->readunlock(idxold >> RCUTORTURE_RDR_SHIFT);
1182
1183 /* Delay if neither beginning nor end and there was a change. */
1184 if ((statesnew || statesold) && *readstate && newstate)
1185 cur_ops->read_delay(trsp, rtrsp);
1186
1187 /* Update the reader state. */
1188 if (idxnew == -1)
1189 idxnew = idxold & ~RCUTORTURE_RDR_MASK;
1190 WARN_ON_ONCE(idxnew < 0);
1191 WARN_ON_ONCE((idxnew >> RCUTORTURE_RDR_SHIFT) > 1);
1192 *readstate = idxnew | newstate;
1193 WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT) < 0);
1194 WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT) > 1);
1195}
1196
1197/* Return the biggest extendables mask given current RCU and boot parameters. */
1198static int rcutorture_extend_mask_max(void)
1199{
1200 int mask;
1201
1202 WARN_ON_ONCE(extendables & ~RCUTORTURE_MAX_EXTEND);
1203 mask = extendables & RCUTORTURE_MAX_EXTEND & cur_ops->extendables;
1204 mask = mask | RCUTORTURE_RDR_RCU;
1205 return mask;
1206}
1207
1208/* Return a random protection state mask, but with at least one bit set. */
1209static int
1210rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp)
1211{
1212 int mask = rcutorture_extend_mask_max();
1213 unsigned long randmask1 = torture_random(trsp) >> 8;
1214 unsigned long randmask2 = randmask1 >> 3;
1215
1216 WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT);
1217 /* Mostly only one bit (need preemption!), sometimes lots of bits. */
1218 if (!(randmask1 & 0x7))
1219 mask = mask & randmask2;
1220 else
1221 mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS));
1222 /* Can't enable bh w/irq disabled. */
1223 if ((mask & RCUTORTURE_RDR_IRQ) &&
1224 ((!(mask & RCUTORTURE_RDR_BH) && (oldmask & RCUTORTURE_RDR_BH)) ||
1225 (!(mask & RCUTORTURE_RDR_RBH) && (oldmask & RCUTORTURE_RDR_RBH))))
1226 mask |= RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH;
1227 return mask ?: RCUTORTURE_RDR_RCU;
1228}
1229
1230/*
1231 * Do a randomly selected number of extensions of an existing RCU read-side
1232 * critical section.
1233 */
1234static struct rt_read_seg *
1235rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp,
1236 struct rt_read_seg *rtrsp)
1237{
1238 int i;
1239 int j;
1240 int mask = rcutorture_extend_mask_max();
1241
1242 WARN_ON_ONCE(!*readstate); /* -Existing- RCU read-side critsect! */
1243 if (!((mask - 1) & mask))
1244 return rtrsp; /* Current RCU reader not extendable. */
1245 /* Bias towards larger numbers of loops. */
1246 i = (torture_random(trsp) >> 3);
1247 i = ((i | (i >> 3)) & RCUTORTURE_RDR_MAX_LOOPS) + 1;
1248 for (j = 0; j < i; j++) {
1249 mask = rcutorture_extend_mask(*readstate, trsp);
1250 rcutorture_one_extend(readstate, mask, trsp, &rtrsp[j]);
1251 }
1252 return &rtrsp[j];
1253}
1254
1255/*
1256 * Do one read-side critical section, returning false if there was
1257 * no data to read. Can be invoked both from process context and
1258 * from a timer handler.
1259 */
1260static bool rcu_torture_one_read(struct torture_random_state *trsp)
1261{
1262 int i;
1263 unsigned long started;
1264 unsigned long completed;
1265 int newstate;
1266 struct rcu_torture *p;
1267 int pipe_count;
1268 int readstate = 0;
1269 struct rt_read_seg rtseg[RCUTORTURE_RDR_MAX_SEGS] = { { 0 } };
1270 struct rt_read_seg *rtrsp = &rtseg[0];
1271 struct rt_read_seg *rtrsp1;
1272 unsigned long long ts;
1273
1274 newstate = rcutorture_extend_mask(readstate, trsp);
1275 rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++);
1276 started = cur_ops->get_gp_seq();
1277 ts = rcu_trace_clock_local();
1278 p = rcu_dereference_check(rcu_torture_current,
1279 rcu_read_lock_bh_held() ||
1280 rcu_read_lock_sched_held() ||
1281 srcu_read_lock_held(srcu_ctlp) ||
1282 torturing_tasks());
1283 if (p == NULL) {
1284 /* Wait for rcu_torture_writer to get underway */
1285 rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
1286 return false;
1287 }
1288 if (p->rtort_mbtest == 0)
1289 atomic_inc(&n_rcu_torture_mberror);
1290 rtrsp = rcutorture_loop_extend(&readstate, trsp, rtrsp);
1291 preempt_disable();
1292 pipe_count = p->rtort_pipe_count;
1293 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1294 /* Should not happen, but... */
1295 pipe_count = RCU_TORTURE_PIPE_LEN;
1296 }
1297 completed = cur_ops->get_gp_seq();
1298 if (pipe_count > 1) {
1299 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
1300 ts, started, completed);
1301 rcu_ftrace_dump(DUMP_ALL);
1302 }
1303 __this_cpu_inc(rcu_torture_count[pipe_count]);
1304 completed = rcutorture_seq_diff(completed, started);
1305 if (completed > RCU_TORTURE_PIPE_LEN) {
1306 /* Should not happen, but... */
1307 completed = RCU_TORTURE_PIPE_LEN;
1308 }
1309 __this_cpu_inc(rcu_torture_batch[completed]);
1310 preempt_enable();
1311 rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
1312 WARN_ON_ONCE(readstate & RCUTORTURE_RDR_MASK);
1313
1314 /* If error or close call, record the sequence of reader protections. */
1315 if ((pipe_count > 1 || completed > 1) && !xchg(&err_segs_recorded, 1)) {
1316 i = 0;
1317 for (rtrsp1 = &rtseg[0]; rtrsp1 < rtrsp; rtrsp1++)
1318 err_segs[i++] = *rtrsp1;
1319 rt_read_nsegs = i;
1320 }
1321
1322 return true;
1323}
1324
1325static DEFINE_TORTURE_RANDOM_PERCPU(rcu_torture_timer_rand);
1326
1327/*
1328 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
1329 * incrementing the corresponding element of the pipeline array. The
1330 * counter in the element should never be greater than 1, otherwise, the
1331 * RCU implementation is broken.
1332 */
1333static void rcu_torture_timer(struct timer_list *unused)
1334{
1335 atomic_long_inc(&n_rcu_torture_timers);
1336 (void)rcu_torture_one_read(this_cpu_ptr(&rcu_torture_timer_rand));
1337
1338 /* Test call_rcu() invocation from interrupt handler. */
1339 if (cur_ops->call) {
1340 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT);
1341
1342 if (rhp)
1343 cur_ops->call(rhp, rcu_torture_timer_cb);
1344 }
1345}
1346
1347/*
1348 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
1349 * incrementing the corresponding element of the pipeline array. The
1350 * counter in the element should never be greater than 1, otherwise, the
1351 * RCU implementation is broken.
1352 */
1353static int
1354rcu_torture_reader(void *arg)
1355{
1356 unsigned long lastsleep = jiffies;
1357 long myid = (long)arg;
1358 int mynumonline = myid;
1359 DEFINE_TORTURE_RANDOM(rand);
1360 struct timer_list t;
1361
1362 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
1363 set_user_nice(current, MAX_NICE);
1364 if (irqreader && cur_ops->irq_capable)
1365 timer_setup_on_stack(&t, rcu_torture_timer, 0);
1366
1367 do {
1368 if (irqreader && cur_ops->irq_capable) {
1369 if (!timer_pending(&t))
1370 mod_timer(&t, jiffies + 1);
1371 }
1372 if (!rcu_torture_one_read(&rand))
1373 schedule_timeout_interruptible(HZ);
1374 if (time_after(jiffies, lastsleep)) {
1375 schedule_timeout_interruptible(1);
1376 lastsleep = jiffies + 10;
1377 }
1378 while (num_online_cpus() < mynumonline && !torture_must_stop())
1379 schedule_timeout_interruptible(HZ / 5);
1380 stutter_wait("rcu_torture_reader");
1381 } while (!torture_must_stop());
1382 if (irqreader && cur_ops->irq_capable) {
1383 del_timer_sync(&t);
1384 destroy_timer_on_stack(&t);
1385 }
1386 torture_kthread_stopping("rcu_torture_reader");
1387 return 0;
1388}
1389
1390/*
1391 * Print torture statistics. Caller must ensure that there is only
1392 * one call to this function at a given time!!! This is normally
1393 * accomplished by relying on the module system to only have one copy
1394 * of the module loaded, and then by giving the rcu_torture_stats
1395 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1396 * thread is not running).
1397 */
1398static void
1399rcu_torture_stats_print(void)
1400{
1401 int cpu;
1402 int i;
1403 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1404 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1405 static unsigned long rtcv_snap = ULONG_MAX;
1406 static bool splatted;
1407 struct task_struct *wtp;
1408
1409 for_each_possible_cpu(cpu) {
1410 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1411 pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
1412 batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
1413 }
1414 }
1415 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
1416 if (pipesummary[i] != 0)
1417 break;
1418 }
1419
1420 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1421 pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
1422 rcu_torture_current,
1423 rcu_torture_current ? "ver" : "VER",
1424 rcu_torture_current_version,
1425 list_empty(&rcu_torture_freelist),
1426 atomic_read(&n_rcu_torture_alloc),
1427 atomic_read(&n_rcu_torture_alloc_fail),
1428 atomic_read(&n_rcu_torture_free));
1429 pr_cont("rtmbe: %d rtbe: %ld rtbke: %ld rtbre: %ld ",
1430 atomic_read(&n_rcu_torture_mberror),
1431 n_rcu_torture_barrier_error,
1432 n_rcu_torture_boost_ktrerror,
1433 n_rcu_torture_boost_rterror);
1434 pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
1435 n_rcu_torture_boost_failure,
1436 n_rcu_torture_boosts,
1437 atomic_long_read(&n_rcu_torture_timers));
1438 torture_onoff_stats();
1439 pr_cont("barrier: %ld/%ld:%ld\n",
1440 n_barrier_successes,
1441 n_barrier_attempts,
1442 n_rcu_torture_barrier_error);
1443
1444 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1445 if (atomic_read(&n_rcu_torture_mberror) != 0 ||
1446 n_rcu_torture_barrier_error != 0 ||
1447 n_rcu_torture_boost_ktrerror != 0 ||
1448 n_rcu_torture_boost_rterror != 0 ||
1449 n_rcu_torture_boost_failure != 0 ||
1450 i > 1) {
1451 pr_cont("%s", "!!! ");
1452 atomic_inc(&n_rcu_torture_error);
1453 WARN_ON_ONCE(1);
1454 }
1455 pr_cont("Reader Pipe: ");
1456 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1457 pr_cont(" %ld", pipesummary[i]);
1458 pr_cont("\n");
1459
1460 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1461 pr_cont("Reader Batch: ");
1462 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1463 pr_cont(" %ld", batchsummary[i]);
1464 pr_cont("\n");
1465
1466 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1467 pr_cont("Free-Block Circulation: ");
1468 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1469 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
1470 }
1471 pr_cont("\n");
1472
1473 if (cur_ops->stats)
1474 cur_ops->stats();
1475 if (rtcv_snap == rcu_torture_current_version &&
1476 rcu_torture_current != NULL) {
1477 int __maybe_unused flags = 0;
1478 unsigned long __maybe_unused gp_seq = 0;
1479
1480 rcutorture_get_gp_data(cur_ops->ttype,
1481 &flags, &gp_seq);
1482 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp,
1483 &flags, &gp_seq);
1484 wtp = READ_ONCE(writer_task);
1485 pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#lx cpu %d\n",
1486 rcu_torture_writer_state_getname(),
1487 rcu_torture_writer_state, gp_seq, flags,
1488 wtp == NULL ? ~0UL : wtp->state,
1489 wtp == NULL ? -1 : (int)task_cpu(wtp));
1490 if (!splatted && wtp) {
1491 sched_show_task(wtp);
1492 splatted = true;
1493 }
1494 show_rcu_gp_kthreads();
1495 rcu_ftrace_dump(DUMP_ALL);
1496 }
1497 rtcv_snap = rcu_torture_current_version;
1498}
1499
1500/*
1501 * Periodically prints torture statistics, if periodic statistics printing
1502 * was specified via the stat_interval module parameter.
1503 */
1504static int
1505rcu_torture_stats(void *arg)
1506{
1507 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1508 do {
1509 schedule_timeout_interruptible(stat_interval * HZ);
1510 rcu_torture_stats_print();
1511 torture_shutdown_absorb("rcu_torture_stats");
1512 } while (!torture_must_stop());
1513 torture_kthread_stopping("rcu_torture_stats");
1514 return 0;
1515}
1516
1517static void
1518rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1519{
1520 pr_alert("%s" TORTURE_FLAG
1521 "--- %s: nreaders=%d nfakewriters=%d "
1522 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1523 "shuffle_interval=%d stutter=%d irqreader=%d "
1524 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1525 "test_boost=%d/%d test_boost_interval=%d "
1526 "test_boost_duration=%d shutdown_secs=%d "
1527 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d "
1528 "n_barrier_cbs=%d "
1529 "onoff_interval=%d onoff_holdoff=%d\n",
1530 torture_type, tag, nrealreaders, nfakewriters,
1531 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1532 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1533 test_boost, cur_ops->can_boost,
1534 test_boost_interval, test_boost_duration, shutdown_secs,
1535 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff,
1536 n_barrier_cbs,
1537 onoff_interval, onoff_holdoff);
1538}
1539
1540static int rcutorture_booster_cleanup(unsigned int cpu)
1541{
1542 struct task_struct *t;
1543
1544 if (boost_tasks[cpu] == NULL)
1545 return 0;
1546 mutex_lock(&boost_mutex);
1547 t = boost_tasks[cpu];
1548 boost_tasks[cpu] = NULL;
1549 rcu_torture_enable_rt_throttle();
1550 mutex_unlock(&boost_mutex);
1551
1552 /* This must be outside of the mutex, otherwise deadlock! */
1553 torture_stop_kthread(rcu_torture_boost, t);
1554 return 0;
1555}
1556
1557static int rcutorture_booster_init(unsigned int cpu)
1558{
1559 int retval;
1560
1561 if (boost_tasks[cpu] != NULL)
1562 return 0; /* Already created, nothing more to do. */
1563
1564 /* Don't allow time recalculation while creating a new task. */
1565 mutex_lock(&boost_mutex);
1566 rcu_torture_disable_rt_throttle();
1567 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
1568 boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
1569 cpu_to_node(cpu),
1570 "rcu_torture_boost");
1571 if (IS_ERR(boost_tasks[cpu])) {
1572 retval = PTR_ERR(boost_tasks[cpu]);
1573 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
1574 n_rcu_torture_boost_ktrerror++;
1575 boost_tasks[cpu] = NULL;
1576 mutex_unlock(&boost_mutex);
1577 return retval;
1578 }
1579 kthread_bind(boost_tasks[cpu], cpu);
1580 wake_up_process(boost_tasks[cpu]);
1581 mutex_unlock(&boost_mutex);
1582 return 0;
1583}
1584
1585/*
1586 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
1587 * induces a CPU stall for the time specified by stall_cpu.
1588 */
1589static int rcu_torture_stall(void *args)
1590{
1591 unsigned long stop_at;
1592
1593 VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
1594 if (stall_cpu_holdoff > 0) {
1595 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
1596 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
1597 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
1598 }
1599 if (!kthread_should_stop()) {
1600 stop_at = ktime_get_seconds() + stall_cpu;
1601 /* RCU CPU stall is expected behavior in following code. */
1602 rcu_read_lock();
1603 if (stall_cpu_irqsoff)
1604 local_irq_disable();
1605 else
1606 preempt_disable();
1607 pr_alert("rcu_torture_stall start on CPU %d.\n",
1608 smp_processor_id());
1609 while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(),
1610 stop_at))
1611 continue; /* Induce RCU CPU stall warning. */
1612 if (stall_cpu_irqsoff)
1613 local_irq_enable();
1614 else
1615 preempt_enable();
1616 rcu_read_unlock();
1617 pr_alert("rcu_torture_stall end.\n");
1618 }
1619 torture_shutdown_absorb("rcu_torture_stall");
1620 while (!kthread_should_stop())
1621 schedule_timeout_interruptible(10 * HZ);
1622 return 0;
1623}
1624
1625/* Spawn CPU-stall kthread, if stall_cpu specified. */
1626static int __init rcu_torture_stall_init(void)
1627{
1628 if (stall_cpu <= 0)
1629 return 0;
1630 return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
1631}
1632
1633/* State structure for forward-progress self-propagating RCU callback. */
1634struct fwd_cb_state {
1635 struct rcu_head rh;
1636 int stop;
1637};
1638
1639/*
1640 * Forward-progress self-propagating RCU callback function. Because
1641 * callbacks run from softirq, this function is an implicit RCU read-side
1642 * critical section.
1643 */
1644static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp)
1645{
1646 struct fwd_cb_state *fcsp = container_of(rhp, struct fwd_cb_state, rh);
1647
1648 if (READ_ONCE(fcsp->stop)) {
1649 WRITE_ONCE(fcsp->stop, 2);
1650 return;
1651 }
1652 cur_ops->call(&fcsp->rh, rcu_torture_fwd_prog_cb);
1653}
1654
1655/* State for continuous-flood RCU callbacks. */
1656struct rcu_fwd_cb {
1657 struct rcu_head rh;
1658 struct rcu_fwd_cb *rfc_next;
1659 int rfc_gps;
1660};
1661static DEFINE_SPINLOCK(rcu_fwd_lock);
1662static struct rcu_fwd_cb *rcu_fwd_cb_head;
1663static struct rcu_fwd_cb **rcu_fwd_cb_tail = &rcu_fwd_cb_head;
1664static long n_launders_cb;
1665static unsigned long rcu_fwd_startat;
1666static bool rcu_fwd_emergency_stop;
1667#define MAX_FWD_CB_JIFFIES (8 * HZ) /* Maximum CB test duration. */
1668#define MIN_FWD_CB_LAUNDERS 3 /* This many CB invocations to count. */
1669#define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */
1670#define FWD_CBS_HIST_DIV 10 /* Histogram buckets/second. */
1671struct rcu_launder_hist {
1672 long n_launders;
1673 unsigned long launder_gp_seq;
1674};
1675#define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV))
1676static struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST];
1677static unsigned long rcu_launder_gp_seq_start;
1678
1679static void rcu_torture_fwd_cb_hist(void)
1680{
1681 unsigned long gps;
1682 unsigned long gps_old;
1683 int i;
1684 int j;
1685
1686 for (i = ARRAY_SIZE(n_launders_hist) - 1; i > 0; i--)
1687 if (n_launders_hist[i].n_launders > 0)
1688 break;
1689 pr_alert("%s: Callback-invocation histogram (duration %lu jiffies):",
1690 __func__, jiffies - rcu_fwd_startat);
1691 gps_old = rcu_launder_gp_seq_start;
1692 for (j = 0; j <= i; j++) {
1693 gps = n_launders_hist[j].launder_gp_seq;
1694 pr_cont(" %ds/%d: %ld:%ld",
1695 j + 1, FWD_CBS_HIST_DIV, n_launders_hist[j].n_launders,
1696 rcutorture_seq_diff(gps, gps_old));
1697 gps_old = gps;
1698 }
1699 pr_cont("\n");
1700}
1701
1702/* Callback function for continuous-flood RCU callbacks. */
1703static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp)
1704{
1705 unsigned long flags;
1706 int i;
1707 struct rcu_fwd_cb *rfcp = container_of(rhp, struct rcu_fwd_cb, rh);
1708 struct rcu_fwd_cb **rfcpp;
1709
1710 rfcp->rfc_next = NULL;
1711 rfcp->rfc_gps++;
1712 spin_lock_irqsave(&rcu_fwd_lock, flags);
1713 rfcpp = rcu_fwd_cb_tail;
1714 rcu_fwd_cb_tail = &rfcp->rfc_next;
1715 WRITE_ONCE(*rfcpp, rfcp);
1716 WRITE_ONCE(n_launders_cb, n_launders_cb + 1);
1717 i = ((jiffies - rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV));
1718 if (i >= ARRAY_SIZE(n_launders_hist))
1719 i = ARRAY_SIZE(n_launders_hist) - 1;
1720 n_launders_hist[i].n_launders++;
1721 n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq();
1722 spin_unlock_irqrestore(&rcu_fwd_lock, flags);
1723}
1724
1725// Give the scheduler a chance, even on nohz_full CPUs.
1726static void rcu_torture_fwd_prog_cond_resched(unsigned long iter)
1727{
1728 if (IS_ENABLED(CONFIG_PREEMPT) && IS_ENABLED(CONFIG_NO_HZ_FULL)) {
1729 // Real call_rcu() floods hit userspace, so emulate that.
1730 if (need_resched() || (iter & 0xfff))
1731 schedule();
1732 } else {
1733 // No userspace emulation: CB invocation throttles call_rcu()
1734 cond_resched();
1735 }
1736}
1737
1738/*
1739 * Free all callbacks on the rcu_fwd_cb_head list, either because the
1740 * test is over or because we hit an OOM event.
1741 */
1742static unsigned long rcu_torture_fwd_prog_cbfree(void)
1743{
1744 unsigned long flags;
1745 unsigned long freed = 0;
1746 struct rcu_fwd_cb *rfcp;
1747
1748 for (;;) {
1749 spin_lock_irqsave(&rcu_fwd_lock, flags);
1750 rfcp = rcu_fwd_cb_head;
1751 if (!rfcp) {
1752 spin_unlock_irqrestore(&rcu_fwd_lock, flags);
1753 break;
1754 }
1755 rcu_fwd_cb_head = rfcp->rfc_next;
1756 if (!rcu_fwd_cb_head)
1757 rcu_fwd_cb_tail = &rcu_fwd_cb_head;
1758 spin_unlock_irqrestore(&rcu_fwd_lock, flags);
1759 kfree(rfcp);
1760 freed++;
1761 rcu_torture_fwd_prog_cond_resched(freed);
1762 }
1763 return freed;
1764}
1765
1766/* Carry out need_resched()/cond_resched() forward-progress testing. */
1767static void rcu_torture_fwd_prog_nr(int *tested, int *tested_tries)
1768{
1769 unsigned long cver;
1770 unsigned long dur;
1771 struct fwd_cb_state fcs;
1772 unsigned long gps;
1773 int idx;
1774 int sd;
1775 int sd4;
1776 bool selfpropcb = false;
1777 unsigned long stopat;
1778 static DEFINE_TORTURE_RANDOM(trs);
1779
1780 if (cur_ops->call && cur_ops->sync && cur_ops->cb_barrier) {
1781 init_rcu_head_on_stack(&fcs.rh);
1782 selfpropcb = true;
1783 }
1784
1785 /* Tight loop containing cond_resched(). */
1786 WRITE_ONCE(rcu_fwd_cb_nodelay, true);
1787 cur_ops->sync(); /* Later readers see above write. */
1788 if (selfpropcb) {
1789 WRITE_ONCE(fcs.stop, 0);
1790 cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb);
1791 }
1792 cver = READ_ONCE(rcu_torture_current_version);
1793 gps = cur_ops->get_gp_seq();
1794 sd = cur_ops->stall_dur() + 1;
1795 sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div;
1796 dur = sd4 + torture_random(&trs) % (sd - sd4);
1797 WRITE_ONCE(rcu_fwd_startat, jiffies);
1798 stopat = rcu_fwd_startat + dur;
1799 while (time_before(jiffies, stopat) &&
1800 !shutdown_time_arrived() &&
1801 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
1802 idx = cur_ops->readlock();
1803 udelay(10);
1804 cur_ops->readunlock(idx);
1805 if (!fwd_progress_need_resched || need_resched())
1806 rcu_torture_fwd_prog_cond_resched(1);
1807 }
1808 (*tested_tries)++;
1809 if (!time_before(jiffies, stopat) &&
1810 !shutdown_time_arrived() &&
1811 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
1812 (*tested)++;
1813 cver = READ_ONCE(rcu_torture_current_version) - cver;
1814 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
1815 WARN_ON(!cver && gps < 2);
1816 pr_alert("%s: Duration %ld cver %ld gps %ld\n", __func__, dur, cver, gps);
1817 }
1818 if (selfpropcb) {
1819 WRITE_ONCE(fcs.stop, 1);
1820 cur_ops->sync(); /* Wait for running CB to complete. */
1821 cur_ops->cb_barrier(); /* Wait for queued callbacks. */
1822 }
1823
1824 if (selfpropcb) {
1825 WARN_ON(READ_ONCE(fcs.stop) != 2);
1826 destroy_rcu_head_on_stack(&fcs.rh);
1827 }
1828 schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */
1829 WRITE_ONCE(rcu_fwd_cb_nodelay, false);
1830}
1831
1832/* Carry out call_rcu() forward-progress testing. */
1833static void rcu_torture_fwd_prog_cr(void)
1834{
1835 unsigned long cver;
1836 unsigned long gps;
1837 int i;
1838 long n_launders;
1839 long n_launders_cb_snap;
1840 long n_launders_sa;
1841 long n_max_cbs;
1842 long n_max_gps;
1843 struct rcu_fwd_cb *rfcp;
1844 struct rcu_fwd_cb *rfcpn;
1845 unsigned long stopat;
1846 unsigned long stoppedat;
1847
1848 if (READ_ONCE(rcu_fwd_emergency_stop))
1849 return; /* Get out of the way quickly, no GP wait! */
1850 if (!cur_ops->call)
1851 return; /* Can't do call_rcu() fwd prog without ->call. */
1852
1853 /* Loop continuously posting RCU callbacks. */
1854 WRITE_ONCE(rcu_fwd_cb_nodelay, true);
1855 cur_ops->sync(); /* Later readers see above write. */
1856 WRITE_ONCE(rcu_fwd_startat, jiffies);
1857 stopat = rcu_fwd_startat + MAX_FWD_CB_JIFFIES;
1858 n_launders = 0;
1859 n_launders_cb = 0;
1860 n_launders_sa = 0;
1861 n_max_cbs = 0;
1862 n_max_gps = 0;
1863 for (i = 0; i < ARRAY_SIZE(n_launders_hist); i++)
1864 n_launders_hist[i].n_launders = 0;
1865 cver = READ_ONCE(rcu_torture_current_version);
1866 gps = cur_ops->get_gp_seq();
1867 rcu_launder_gp_seq_start = gps;
1868 while (time_before(jiffies, stopat) &&
1869 !shutdown_time_arrived() &&
1870 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
1871 rfcp = READ_ONCE(rcu_fwd_cb_head);
1872 rfcpn = NULL;
1873 if (rfcp)
1874 rfcpn = READ_ONCE(rfcp->rfc_next);
1875 if (rfcpn) {
1876 if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS &&
1877 ++n_max_gps >= MIN_FWD_CBS_LAUNDERED)
1878 break;
1879 rcu_fwd_cb_head = rfcpn;
1880 n_launders++;
1881 n_launders_sa++;
1882 } else {
1883 rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL);
1884 if (WARN_ON_ONCE(!rfcp)) {
1885 schedule_timeout_interruptible(1);
1886 continue;
1887 }
1888 n_max_cbs++;
1889 n_launders_sa = 0;
1890 rfcp->rfc_gps = 0;
1891 }
1892 cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr);
1893 rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs);
1894 }
1895 stoppedat = jiffies;
1896 n_launders_cb_snap = READ_ONCE(n_launders_cb);
1897 cver = READ_ONCE(rcu_torture_current_version) - cver;
1898 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
1899 cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */
1900 (void)rcu_torture_fwd_prog_cbfree();
1901
1902 if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) &&
1903 !shutdown_time_arrived()) {
1904 WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED);
1905 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",
1906 __func__,
1907 stoppedat - rcu_fwd_startat, jiffies - stoppedat,
1908 n_launders + n_max_cbs - n_launders_cb_snap,
1909 n_launders, n_launders_sa,
1910 n_max_gps, n_max_cbs, cver, gps);
1911 rcu_torture_fwd_cb_hist();
1912 }
1913 schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */
1914 WRITE_ONCE(rcu_fwd_cb_nodelay, false);
1915}
1916
1917
1918/*
1919 * OOM notifier, but this only prints diagnostic information for the
1920 * current forward-progress test.
1921 */
1922static int rcutorture_oom_notify(struct notifier_block *self,
1923 unsigned long notused, void *nfreed)
1924{
1925 WARN(1, "%s invoked upon OOM during forward-progress testing.\n",
1926 __func__);
1927 rcu_torture_fwd_cb_hist();
1928 rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rcu_fwd_startat)) / 2);
1929 WRITE_ONCE(rcu_fwd_emergency_stop, true);
1930 smp_mb(); /* Emergency stop before free and wait to avoid hangs. */
1931 pr_info("%s: Freed %lu RCU callbacks.\n",
1932 __func__, rcu_torture_fwd_prog_cbfree());
1933 rcu_barrier();
1934 pr_info("%s: Freed %lu RCU callbacks.\n",
1935 __func__, rcu_torture_fwd_prog_cbfree());
1936 rcu_barrier();
1937 pr_info("%s: Freed %lu RCU callbacks.\n",
1938 __func__, rcu_torture_fwd_prog_cbfree());
1939 smp_mb(); /* Frees before return to avoid redoing OOM. */
1940 (*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */
1941 pr_info("%s returning after OOM processing.\n", __func__);
1942 return NOTIFY_OK;
1943}
1944
1945static struct notifier_block rcutorture_oom_nb = {
1946 .notifier_call = rcutorture_oom_notify
1947};
1948
1949/* Carry out grace-period forward-progress testing. */
1950static int rcu_torture_fwd_prog(void *args)
1951{
1952 int tested = 0;
1953 int tested_tries = 0;
1954
1955 VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started");
1956 rcu_bind_current_to_nocb();
1957 if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST))
1958 set_user_nice(current, MAX_NICE);
1959 do {
1960 schedule_timeout_interruptible(fwd_progress_holdoff * HZ);
1961 WRITE_ONCE(rcu_fwd_emergency_stop, false);
1962 register_oom_notifier(&rcutorture_oom_nb);
1963 rcu_torture_fwd_prog_nr(&tested, &tested_tries);
1964 rcu_torture_fwd_prog_cr();
1965 unregister_oom_notifier(&rcutorture_oom_nb);
1966
1967 /* Avoid slow periods, better to test when busy. */
1968 stutter_wait("rcu_torture_fwd_prog");
1969 } while (!torture_must_stop());
1970 /* Short runs might not contain a valid forward-progress attempt. */
1971 WARN_ON(!tested && tested_tries >= 5);
1972 pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries);
1973 torture_kthread_stopping("rcu_torture_fwd_prog");
1974 return 0;
1975}
1976
1977/* If forward-progress checking is requested and feasible, spawn the thread. */
1978static int __init rcu_torture_fwd_prog_init(void)
1979{
1980 if (!fwd_progress)
1981 return 0; /* Not requested, so don't do it. */
1982 if (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0 ||
1983 cur_ops == &rcu_busted_ops) {
1984 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test");
1985 return 0;
1986 }
1987 if (stall_cpu > 0) {
1988 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing");
1989 if (IS_MODULE(CONFIG_RCU_TORTURE_TESTS))
1990 return -EINVAL; /* In module, can fail back to user. */
1991 WARN_ON(1); /* Make sure rcutorture notices conflict. */
1992 return 0;
1993 }
1994 if (fwd_progress_holdoff <= 0)
1995 fwd_progress_holdoff = 1;
1996 if (fwd_progress_div <= 0)
1997 fwd_progress_div = 4;
1998 return torture_create_kthread(rcu_torture_fwd_prog,
1999 NULL, fwd_prog_task);
2000}
2001
2002/* Callback function for RCU barrier testing. */
2003static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
2004{
2005 atomic_inc(&barrier_cbs_invoked);
2006}
2007
2008/* kthread function to register callbacks used to test RCU barriers. */
2009static int rcu_torture_barrier_cbs(void *arg)
2010{
2011 long myid = (long)arg;
2012 bool lastphase = 0;
2013 bool newphase;
2014 struct rcu_head rcu;
2015
2016 init_rcu_head_on_stack(&rcu);
2017 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
2018 set_user_nice(current, MAX_NICE);
2019 do {
2020 wait_event(barrier_cbs_wq[myid],
2021 (newphase =
2022 smp_load_acquire(&barrier_phase)) != lastphase ||
2023 torture_must_stop());
2024 lastphase = newphase;
2025 if (torture_must_stop())
2026 break;
2027 /*
2028 * The above smp_load_acquire() ensures barrier_phase load
2029 * is ordered before the following ->call().
2030 */
2031 local_irq_disable(); /* Just to test no-irq call_rcu(). */
2032 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
2033 local_irq_enable();
2034 if (atomic_dec_and_test(&barrier_cbs_count))
2035 wake_up(&barrier_wq);
2036 } while (!torture_must_stop());
2037 if (cur_ops->cb_barrier != NULL)
2038 cur_ops->cb_barrier();
2039 destroy_rcu_head_on_stack(&rcu);
2040 torture_kthread_stopping("rcu_torture_barrier_cbs");
2041 return 0;
2042}
2043
2044/* kthread function to drive and coordinate RCU barrier testing. */
2045static int rcu_torture_barrier(void *arg)
2046{
2047 int i;
2048
2049 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
2050 do {
2051 atomic_set(&barrier_cbs_invoked, 0);
2052 atomic_set(&barrier_cbs_count, n_barrier_cbs);
2053 /* Ensure barrier_phase ordered after prior assignments. */
2054 smp_store_release(&barrier_phase, !barrier_phase);
2055 for (i = 0; i < n_barrier_cbs; i++)
2056 wake_up(&barrier_cbs_wq[i]);
2057 wait_event(barrier_wq,
2058 atomic_read(&barrier_cbs_count) == 0 ||
2059 torture_must_stop());
2060 if (torture_must_stop())
2061 break;
2062 n_barrier_attempts++;
2063 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
2064 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
2065 n_rcu_torture_barrier_error++;
2066 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
2067 atomic_read(&barrier_cbs_invoked),
2068 n_barrier_cbs);
2069 WARN_ON_ONCE(1);
2070 } else {
2071 n_barrier_successes++;
2072 }
2073 schedule_timeout_interruptible(HZ / 10);
2074 } while (!torture_must_stop());
2075 torture_kthread_stopping("rcu_torture_barrier");
2076 return 0;
2077}
2078
2079/* Initialize RCU barrier testing. */
2080static int rcu_torture_barrier_init(void)
2081{
2082 int i;
2083 int ret;
2084
2085 if (n_barrier_cbs <= 0)
2086 return 0;
2087 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
2088 pr_alert("%s" TORTURE_FLAG
2089 " Call or barrier ops missing for %s,\n",
2090 torture_type, cur_ops->name);
2091 pr_alert("%s" TORTURE_FLAG
2092 " RCU barrier testing omitted from run.\n",
2093 torture_type);
2094 return 0;
2095 }
2096 atomic_set(&barrier_cbs_count, 0);
2097 atomic_set(&barrier_cbs_invoked, 0);
2098 barrier_cbs_tasks =
2099 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]),
2100 GFP_KERNEL);
2101 barrier_cbs_wq =
2102 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL);
2103 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
2104 return -ENOMEM;
2105 for (i = 0; i < n_barrier_cbs; i++) {
2106 init_waitqueue_head(&barrier_cbs_wq[i]);
2107 ret = torture_create_kthread(rcu_torture_barrier_cbs,
2108 (void *)(long)i,
2109 barrier_cbs_tasks[i]);
2110 if (ret)
2111 return ret;
2112 }
2113 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
2114}
2115
2116/* Clean up after RCU barrier testing. */
2117static void rcu_torture_barrier_cleanup(void)
2118{
2119 int i;
2120
2121 torture_stop_kthread(rcu_torture_barrier, barrier_task);
2122 if (barrier_cbs_tasks != NULL) {
2123 for (i = 0; i < n_barrier_cbs; i++)
2124 torture_stop_kthread(rcu_torture_barrier_cbs,
2125 barrier_cbs_tasks[i]);
2126 kfree(barrier_cbs_tasks);
2127 barrier_cbs_tasks = NULL;
2128 }
2129 if (barrier_cbs_wq != NULL) {
2130 kfree(barrier_cbs_wq);
2131 barrier_cbs_wq = NULL;
2132 }
2133}
2134
2135static bool rcu_torture_can_boost(void)
2136{
2137 static int boost_warn_once;
2138 int prio;
2139
2140 if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2)
2141 return false;
2142
2143 prio = rcu_get_gp_kthreads_prio();
2144 if (!prio)
2145 return false;
2146
2147 if (prio < 2) {
2148 if (boost_warn_once == 1)
2149 return false;
2150
2151 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);
2152 boost_warn_once = 1;
2153 return false;
2154 }
2155
2156 return true;
2157}
2158
2159static enum cpuhp_state rcutor_hp;
2160
2161static void
2162rcu_torture_cleanup(void)
2163{
2164 int firsttime;
2165 int flags = 0;
2166 unsigned long gp_seq = 0;
2167 int i;
2168
2169 if (torture_cleanup_begin()) {
2170 if (cur_ops->cb_barrier != NULL)
2171 cur_ops->cb_barrier();
2172 return;
2173 }
2174 if (!cur_ops) {
2175 torture_cleanup_end();
2176 return;
2177 }
2178
2179 show_rcu_gp_kthreads();
2180 rcu_torture_barrier_cleanup();
2181 torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_task);
2182 torture_stop_kthread(rcu_torture_stall, stall_task);
2183 torture_stop_kthread(rcu_torture_writer, writer_task);
2184
2185 if (reader_tasks) {
2186 for (i = 0; i < nrealreaders; i++)
2187 torture_stop_kthread(rcu_torture_reader,
2188 reader_tasks[i]);
2189 kfree(reader_tasks);
2190 }
2191 rcu_torture_current = NULL;
2192
2193 if (fakewriter_tasks) {
2194 for (i = 0; i < nfakewriters; i++) {
2195 torture_stop_kthread(rcu_torture_fakewriter,
2196 fakewriter_tasks[i]);
2197 }
2198 kfree(fakewriter_tasks);
2199 fakewriter_tasks = NULL;
2200 }
2201
2202 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq);
2203 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq);
2204 pr_alert("%s: End-test grace-period state: g%lu f%#x\n",
2205 cur_ops->name, gp_seq, flags);
2206 torture_stop_kthread(rcu_torture_stats, stats_task);
2207 torture_stop_kthread(rcu_torture_fqs, fqs_task);
2208 if (rcu_torture_can_boost())
2209 cpuhp_remove_state(rcutor_hp);
2210
2211 /*
2212 * Wait for all RCU callbacks to fire, then do torture-type-specific
2213 * cleanup operations.
2214 */
2215 if (cur_ops->cb_barrier != NULL)
2216 cur_ops->cb_barrier();
2217 if (cur_ops->cleanup != NULL)
2218 cur_ops->cleanup();
2219
2220 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
2221
2222 if (err_segs_recorded) {
2223 pr_alert("Failure/close-call rcutorture reader segments:\n");
2224 if (rt_read_nsegs == 0)
2225 pr_alert("\t: No segments recorded!!!\n");
2226 firsttime = 1;
2227 for (i = 0; i < rt_read_nsegs; i++) {
2228 pr_alert("\t%d: %#x ", i, err_segs[i].rt_readstate);
2229 if (err_segs[i].rt_delay_jiffies != 0) {
2230 pr_cont("%s%ldjiffies", firsttime ? "" : "+",
2231 err_segs[i].rt_delay_jiffies);
2232 firsttime = 0;
2233 }
2234 if (err_segs[i].rt_delay_ms != 0) {
2235 pr_cont("%s%ldms", firsttime ? "" : "+",
2236 err_segs[i].rt_delay_ms);
2237 firsttime = 0;
2238 }
2239 if (err_segs[i].rt_delay_us != 0) {
2240 pr_cont("%s%ldus", firsttime ? "" : "+",
2241 err_segs[i].rt_delay_us);
2242 firsttime = 0;
2243 }
2244 pr_cont("%s\n",
2245 err_segs[i].rt_preempted ? "preempted" : "");
2246
2247 }
2248 }
2249 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
2250 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
2251 else if (torture_onoff_failures())
2252 rcu_torture_print_module_parms(cur_ops,
2253 "End of test: RCU_HOTPLUG");
2254 else
2255 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
2256 torture_cleanup_end();
2257}
2258
2259#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
2260static void rcu_torture_leak_cb(struct rcu_head *rhp)
2261{
2262}
2263
2264static void rcu_torture_err_cb(struct rcu_head *rhp)
2265{
2266 /*
2267 * This -might- happen due to race conditions, but is unlikely.
2268 * The scenario that leads to this happening is that the
2269 * first of the pair of duplicate callbacks is queued,
2270 * someone else starts a grace period that includes that
2271 * callback, then the second of the pair must wait for the
2272 * next grace period. Unlikely, but can happen. If it
2273 * does happen, the debug-objects subsystem won't have splatted.
2274 */
2275 pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME);
2276}
2277#endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
2278
2279/*
2280 * Verify that double-free causes debug-objects to complain, but only
2281 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
2282 * cannot be carried out.
2283 */
2284static void rcu_test_debug_objects(void)
2285{
2286#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
2287 struct rcu_head rh1;
2288 struct rcu_head rh2;
2289
2290 init_rcu_head_on_stack(&rh1);
2291 init_rcu_head_on_stack(&rh2);
2292 pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME);
2293
2294 /* Try to queue the rh2 pair of callbacks for the same grace period. */
2295 preempt_disable(); /* Prevent preemption from interrupting test. */
2296 rcu_read_lock(); /* Make it impossible to finish a grace period. */
2297 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
2298 local_irq_disable(); /* Make it harder to start a new grace period. */
2299 call_rcu(&rh2, rcu_torture_leak_cb);
2300 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
2301 local_irq_enable();
2302 rcu_read_unlock();
2303 preempt_enable();
2304
2305 /* Wait for them all to get done so we can safely return. */
2306 rcu_barrier();
2307 pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME);
2308 destroy_rcu_head_on_stack(&rh1);
2309 destroy_rcu_head_on_stack(&rh2);
2310#else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
2311 pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME);
2312#endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
2313}
2314
2315static void rcutorture_sync(void)
2316{
2317 static unsigned long n;
2318
2319 if (cur_ops->sync && !(++n & 0xfff))
2320 cur_ops->sync();
2321}
2322
2323static int __init
2324rcu_torture_init(void)
2325{
2326 long i;
2327 int cpu;
2328 int firsterr = 0;
2329 static struct rcu_torture_ops *torture_ops[] = {
2330 &rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops,
2331 &busted_srcud_ops, &tasks_ops, &trivial_ops,
2332 };
2333
2334 if (!torture_init_begin(torture_type, verbose))
2335 return -EBUSY;
2336
2337 /* Process args and tell the world that the torturer is on the job. */
2338 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
2339 cur_ops = torture_ops[i];
2340 if (strcmp(torture_type, cur_ops->name) == 0)
2341 break;
2342 }
2343 if (i == ARRAY_SIZE(torture_ops)) {
2344 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
2345 torture_type);
2346 pr_alert("rcu-torture types:");
2347 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
2348 pr_cont(" %s", torture_ops[i]->name);
2349 pr_cont("\n");
2350 WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST));
2351 firsterr = -EINVAL;
2352 cur_ops = NULL;
2353 goto unwind;
2354 }
2355 if (cur_ops->fqs == NULL && fqs_duration != 0) {
2356 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
2357 fqs_duration = 0;
2358 }
2359 if (cur_ops->init)
2360 cur_ops->init();
2361
2362 if (nreaders >= 0) {
2363 nrealreaders = nreaders;
2364 } else {
2365 nrealreaders = num_online_cpus() - 2 - nreaders;
2366 if (nrealreaders <= 0)
2367 nrealreaders = 1;
2368 }
2369 rcu_torture_print_module_parms(cur_ops, "Start of test");
2370
2371 /* Set up the freelist. */
2372
2373 INIT_LIST_HEAD(&rcu_torture_freelist);
2374 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
2375 rcu_tortures[i].rtort_mbtest = 0;
2376 list_add_tail(&rcu_tortures[i].rtort_free,
2377 &rcu_torture_freelist);
2378 }
2379
2380 /* Initialize the statistics so that each run gets its own numbers. */
2381
2382 rcu_torture_current = NULL;
2383 rcu_torture_current_version = 0;
2384 atomic_set(&n_rcu_torture_alloc, 0);
2385 atomic_set(&n_rcu_torture_alloc_fail, 0);
2386 atomic_set(&n_rcu_torture_free, 0);
2387 atomic_set(&n_rcu_torture_mberror, 0);
2388 atomic_set(&n_rcu_torture_error, 0);
2389 n_rcu_torture_barrier_error = 0;
2390 n_rcu_torture_boost_ktrerror = 0;
2391 n_rcu_torture_boost_rterror = 0;
2392 n_rcu_torture_boost_failure = 0;
2393 n_rcu_torture_boosts = 0;
2394 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
2395 atomic_set(&rcu_torture_wcount[i], 0);
2396 for_each_possible_cpu(cpu) {
2397 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
2398 per_cpu(rcu_torture_count, cpu)[i] = 0;
2399 per_cpu(rcu_torture_batch, cpu)[i] = 0;
2400 }
2401 }
2402 err_segs_recorded = 0;
2403 rt_read_nsegs = 0;
2404
2405 /* Start up the kthreads. */
2406
2407 firsterr = torture_create_kthread(rcu_torture_writer, NULL,
2408 writer_task);
2409 if (firsterr)
2410 goto unwind;
2411 if (nfakewriters > 0) {
2412 fakewriter_tasks = kcalloc(nfakewriters,
2413 sizeof(fakewriter_tasks[0]),
2414 GFP_KERNEL);
2415 if (fakewriter_tasks == NULL) {
2416 VERBOSE_TOROUT_ERRSTRING("out of memory");
2417 firsterr = -ENOMEM;
2418 goto unwind;
2419 }
2420 }
2421 for (i = 0; i < nfakewriters; i++) {
2422 firsterr = torture_create_kthread(rcu_torture_fakewriter,
2423 NULL, fakewriter_tasks[i]);
2424 if (firsterr)
2425 goto unwind;
2426 }
2427 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
2428 GFP_KERNEL);
2429 if (reader_tasks == NULL) {
2430 VERBOSE_TOROUT_ERRSTRING("out of memory");
2431 firsterr = -ENOMEM;
2432 goto unwind;
2433 }
2434 for (i = 0; i < nrealreaders; i++) {
2435 firsterr = torture_create_kthread(rcu_torture_reader, (void *)i,
2436 reader_tasks[i]);
2437 if (firsterr)
2438 goto unwind;
2439 }
2440 if (stat_interval > 0) {
2441 firsterr = torture_create_kthread(rcu_torture_stats, NULL,
2442 stats_task);
2443 if (firsterr)
2444 goto unwind;
2445 }
2446 if (test_no_idle_hz && shuffle_interval > 0) {
2447 firsterr = torture_shuffle_init(shuffle_interval * HZ);
2448 if (firsterr)
2449 goto unwind;
2450 }
2451 if (stutter < 0)
2452 stutter = 0;
2453 if (stutter) {
2454 int t;
2455
2456 t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ;
2457 firsterr = torture_stutter_init(stutter * HZ, t);
2458 if (firsterr)
2459 goto unwind;
2460 }
2461 if (fqs_duration < 0)
2462 fqs_duration = 0;
2463 if (fqs_duration) {
2464 /* Create the fqs thread */
2465 firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
2466 fqs_task);
2467 if (firsterr)
2468 goto unwind;
2469 }
2470 if (test_boost_interval < 1)
2471 test_boost_interval = 1;
2472 if (test_boost_duration < 2)
2473 test_boost_duration = 2;
2474 if (rcu_torture_can_boost()) {
2475
2476 boost_starttime = jiffies + test_boost_interval * HZ;
2477
2478 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE",
2479 rcutorture_booster_init,
2480 rcutorture_booster_cleanup);
2481 if (firsterr < 0)
2482 goto unwind;
2483 rcutor_hp = firsterr;
2484 }
2485 shutdown_jiffies = jiffies + shutdown_secs * HZ;
2486 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
2487 if (firsterr)
2488 goto unwind;
2489 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval,
2490 rcutorture_sync);
2491 if (firsterr)
2492 goto unwind;
2493 firsterr = rcu_torture_stall_init();
2494 if (firsterr)
2495 goto unwind;
2496 firsterr = rcu_torture_fwd_prog_init();
2497 if (firsterr)
2498 goto unwind;
2499 firsterr = rcu_torture_barrier_init();
2500 if (firsterr)
2501 goto unwind;
2502 if (object_debug)
2503 rcu_test_debug_objects();
2504 torture_init_end();
2505 return 0;
2506
2507unwind:
2508 torture_init_end();
2509 rcu_torture_cleanup();
2510 return firsterr;
2511}
2512
2513module_init(rcu_torture_init);
2514module_exit(rcu_torture_cleanup);