1 /*
2 * Read-Copy Update module-based torture test facility
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, you can access it online at
16 * http://www.gnu.org/licenses/gpl-2.0.html.
17 *
18 * Copyright (C) IBM Corporation, 2005, 2006
19 *
20 * Authors: Paul E. McKenney <paulmck@us.ibm.com>
21 * Josh Triplett <josh@joshtriplett.org>
22 *
23 * See also: Documentation/RCU/torture.txt
24 */
25 #include <linux/types.h>
26 #include <linux/kernel.h>
27 #include <linux/init.h>
28 #include <linux/module.h>
29 #include <linux/kthread.h>
30 #include <linux/err.h>
31 #include <linux/spinlock.h>
32 #include <linux/smp.h>
33 #include <linux/rcupdate.h>
34 #include <linux/interrupt.h>
35 #include <linux/sched.h>
36 #include <linux/atomic.h>
37 #include <linux/bitops.h>
38 #include <linux/completion.h>
39 #include <linux/moduleparam.h>
40 #include <linux/percpu.h>
41 #include <linux/notifier.h>
42 #include <linux/reboot.h>
43 #include <linux/freezer.h>
44 #include <linux/cpu.h>
45 #include <linux/delay.h>
46 #include <linux/stat.h>
47 #include <linux/srcu.h>
48 #include <linux/slab.h>
49 #include <linux/trace_clock.h>
50 #include <asm/byteorder.h>
51 #include <linux/torture.h>
52 #include <linux/vmalloc.h>
53
54 MODULE_LICENSE("GPL");
55 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
56
57
58 torture_param(int, cbflood_inter_holdoff, HZ,
59 "Holdoff between floods (jiffies)");
60 torture_param(int, cbflood_intra_holdoff, 1,
61 "Holdoff between bursts (jiffies)");
62 torture_param(int, cbflood_n_burst, 3, "# bursts in flood, zero to disable");
63 torture_param(int, cbflood_n_per_burst, 20000,
64 "# callbacks per burst in flood");
65 torture_param(int, fqs_duration, 0,
66 "Duration of fqs bursts (us), 0 to disable");
67 torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
68 torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
69 torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
70 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
71 torture_param(bool, gp_normal, false,
72 "Use normal (non-expedited) GP wait primitives");
73 torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
74 torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
75 torture_param(int, n_barrier_cbs, 0,
76 "# of callbacks/kthreads for barrier testing");
77 torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
78 torture_param(int, nreaders, -1, "Number of RCU reader threads");
79 torture_param(int, object_debug, 0,
80 "Enable debug-object double call_rcu() testing");
81 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
82 torture_param(int, onoff_interval, 0,
83 "Time between CPU hotplugs (s), 0=disable");
84 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
85 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
86 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
87 torture_param(int, stall_cpu_holdoff, 10,
88 "Time to wait before starting stall (s).");
89 torture_param(int, stat_interval, 60,
90 "Number of seconds between stats printk()s");
91 torture_param(int, stutter, 5, "Number of seconds to run/halt test");
92 torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
93 torture_param(int, test_boost_duration, 4,
94 "Duration of each boost test, seconds.");
95 torture_param(int, test_boost_interval, 7,
96 "Interval between boost tests, seconds.");
97 torture_param(bool, test_no_idle_hz, true,
98 "Test support for tickless idle CPUs");
99 torture_param(bool, verbose, true,
100 "Enable verbose debugging printk()s");
101
102 static char *torture_type = "rcu";
103 module_param(torture_type, charp, 0444);
104 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, ...)");
105
106 static int nrealreaders;
107 static int ncbflooders;
108 static struct task_struct *writer_task;
109 static struct task_struct **fakewriter_tasks;
110 static struct task_struct **reader_tasks;
111 static struct task_struct *stats_task;
112 static struct task_struct **cbflood_task;
113 static struct task_struct *fqs_task;
114 static struct task_struct *boost_tasks[NR_CPUS];
115 static struct task_struct *stall_task;
116 static struct task_struct **barrier_cbs_tasks;
117 static struct task_struct *barrier_task;
118
119 #define RCU_TORTURE_PIPE_LEN 10
120
121 struct rcu_torture {
122 struct rcu_head rtort_rcu;
123 int rtort_pipe_count;
124 struct list_head rtort_free;
125 int rtort_mbtest;
126 };
127
128 static LIST_HEAD(rcu_torture_freelist);
129 static struct rcu_torture __rcu *rcu_torture_current;
130 static unsigned long rcu_torture_current_version;
131 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
132 static DEFINE_SPINLOCK(rcu_torture_lock);
133 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1],
134 rcu_torture_count) = { 0 };
135 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1],
136 rcu_torture_batch) = { 0 };
137 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
138 static atomic_t n_rcu_torture_alloc;
139 static atomic_t n_rcu_torture_alloc_fail;
140 static atomic_t n_rcu_torture_free;
141 static atomic_t n_rcu_torture_mberror;
142 static atomic_t n_rcu_torture_error;
143 static long n_rcu_torture_barrier_error;
144 static long n_rcu_torture_boost_ktrerror;
145 static long n_rcu_torture_boost_rterror;
146 static long n_rcu_torture_boost_failure;
147 static long n_rcu_torture_boosts;
148 static long n_rcu_torture_timers;
149 static long n_barrier_attempts;
150 static long n_barrier_successes;
151 static atomic_long_t n_cbfloods;
152 static struct list_head rcu_torture_removed;
153
154 static int rcu_torture_writer_state;
155 #define RTWS_FIXED_DELAY 0
156 #define RTWS_DELAY 1
157 #define RTWS_REPLACE 2
158 #define RTWS_DEF_FREE 3
159 #define RTWS_EXP_SYNC 4
160 #define RTWS_COND_GET 5
161 #define RTWS_COND_SYNC 6
162 #define RTWS_SYNC 7
163 #define RTWS_STUTTER 8
164 #define RTWS_STOPPING 9
165
166 #if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
167 #define RCUTORTURE_RUNNABLE_INIT 1
168 #else
169 #define RCUTORTURE_RUNNABLE_INIT 0
170 #endif
171 static int torture_runnable = RCUTORTURE_RUNNABLE_INIT;
172 module_param(torture_runnable, int, 0444);
173 MODULE_PARM_DESC(torture_runnable, "Start rcutorture at boot");
174
175 #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
176 #define rcu_can_boost() 1
177 #else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
178 #define rcu_can_boost() 0
179 #endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
180
181 #ifdef CONFIG_RCU_TRACE
rcu_trace_clock_local(void)182 static u64 notrace rcu_trace_clock_local(void)
183 {
184 u64 ts = trace_clock_local();
185 unsigned long __maybe_unused ts_rem = do_div(ts, NSEC_PER_USEC);
186 return ts;
187 }
188 #else /* #ifdef CONFIG_RCU_TRACE */
rcu_trace_clock_local(void)189 static u64 notrace rcu_trace_clock_local(void)
190 {
191 return 0ULL;
192 }
193 #endif /* #else #ifdef CONFIG_RCU_TRACE */
194
195 static unsigned long boost_starttime; /* jiffies of next boost test start. */
196 static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
197 /* and boost task create/destroy. */
198 static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
199 static bool barrier_phase; /* Test phase. */
200 static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
201 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
202 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
203
204 /*
205 * Allocate an element from the rcu_tortures pool.
206 */
207 static struct rcu_torture *
rcu_torture_alloc(void)208 rcu_torture_alloc(void)
209 {
210 struct list_head *p;
211
212 spin_lock_bh(&rcu_torture_lock);
213 if (list_empty(&rcu_torture_freelist)) {
214 atomic_inc(&n_rcu_torture_alloc_fail);
215 spin_unlock_bh(&rcu_torture_lock);
216 return NULL;
217 }
218 atomic_inc(&n_rcu_torture_alloc);
219 p = rcu_torture_freelist.next;
220 list_del_init(p);
221 spin_unlock_bh(&rcu_torture_lock);
222 return container_of(p, struct rcu_torture, rtort_free);
223 }
224
225 /*
226 * Free an element to the rcu_tortures pool.
227 */
228 static void
rcu_torture_free(struct rcu_torture * p)229 rcu_torture_free(struct rcu_torture *p)
230 {
231 atomic_inc(&n_rcu_torture_free);
232 spin_lock_bh(&rcu_torture_lock);
233 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
234 spin_unlock_bh(&rcu_torture_lock);
235 }
236
237 /*
238 * Operations vector for selecting different types of tests.
239 */
240
241 struct rcu_torture_ops {
242 int ttype;
243 void (*init)(void);
244 int (*readlock)(void);
245 void (*read_delay)(struct torture_random_state *rrsp);
246 void (*readunlock)(int idx);
247 int (*completed)(void);
248 void (*deferred_free)(struct rcu_torture *p);
249 void (*sync)(void);
250 void (*exp_sync)(void);
251 unsigned long (*get_state)(void);
252 void (*cond_sync)(unsigned long oldstate);
253 void (*call)(struct rcu_head *head, void (*func)(struct rcu_head *rcu));
254 void (*cb_barrier)(void);
255 void (*fqs)(void);
256 void (*stats)(void);
257 int irq_capable;
258 int can_boost;
259 const char *name;
260 };
261
262 static struct rcu_torture_ops *cur_ops;
263
264 /*
265 * Definitions for rcu torture testing.
266 */
267
rcu_torture_read_lock(void)268 static int rcu_torture_read_lock(void) __acquires(RCU)
269 {
270 rcu_read_lock();
271 return 0;
272 }
273
rcu_read_delay(struct torture_random_state * rrsp)274 static void rcu_read_delay(struct torture_random_state *rrsp)
275 {
276 const unsigned long shortdelay_us = 200;
277 const unsigned long longdelay_ms = 50;
278
279 /* We want a short delay sometimes to make a reader delay the grace
280 * period, and we want a long delay occasionally to trigger
281 * force_quiescent_state. */
282
283 if (!(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms)))
284 mdelay(longdelay_ms);
285 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
286 udelay(shortdelay_us);
287 #ifdef CONFIG_PREEMPT
288 if (!preempt_count() &&
289 !(torture_random(rrsp) % (nrealreaders * 20000)))
290 preempt_schedule(); /* No QS if preempt_disable() in effect */
291 #endif
292 }
293
rcu_torture_read_unlock(int idx)294 static void rcu_torture_read_unlock(int idx) __releases(RCU)
295 {
296 rcu_read_unlock();
297 }
298
rcu_torture_completed(void)299 static int rcu_torture_completed(void)
300 {
301 return rcu_batches_completed();
302 }
303
304 /*
305 * Update callback in the pipe. This should be invoked after a grace period.
306 */
307 static bool
rcu_torture_pipe_update_one(struct rcu_torture * rp)308 rcu_torture_pipe_update_one(struct rcu_torture *rp)
309 {
310 int i;
311
312 i = rp->rtort_pipe_count;
313 if (i > RCU_TORTURE_PIPE_LEN)
314 i = RCU_TORTURE_PIPE_LEN;
315 atomic_inc(&rcu_torture_wcount[i]);
316 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
317 rp->rtort_mbtest = 0;
318 return true;
319 }
320 return false;
321 }
322
323 /*
324 * Update all callbacks in the pipe. Suitable for synchronous grace-period
325 * primitives.
326 */
327 static void
rcu_torture_pipe_update(struct rcu_torture * old_rp)328 rcu_torture_pipe_update(struct rcu_torture *old_rp)
329 {
330 struct rcu_torture *rp;
331 struct rcu_torture *rp1;
332
333 if (old_rp)
334 list_add(&old_rp->rtort_free, &rcu_torture_removed);
335 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
336 if (rcu_torture_pipe_update_one(rp)) {
337 list_del(&rp->rtort_free);
338 rcu_torture_free(rp);
339 }
340 }
341 }
342
343 static void
rcu_torture_cb(struct rcu_head * p)344 rcu_torture_cb(struct rcu_head *p)
345 {
346 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
347
348 if (torture_must_stop_irq()) {
349 /* Test is ending, just drop callbacks on the floor. */
350 /* The next initialization will pick up the pieces. */
351 return;
352 }
353 if (rcu_torture_pipe_update_one(rp))
354 rcu_torture_free(rp);
355 else
356 cur_ops->deferred_free(rp);
357 }
358
rcu_no_completed(void)359 static int rcu_no_completed(void)
360 {
361 return 0;
362 }
363
rcu_torture_deferred_free(struct rcu_torture * p)364 static void rcu_torture_deferred_free(struct rcu_torture *p)
365 {
366 call_rcu(&p->rtort_rcu, rcu_torture_cb);
367 }
368
rcu_sync_torture_init(void)369 static void rcu_sync_torture_init(void)
370 {
371 INIT_LIST_HEAD(&rcu_torture_removed);
372 }
373
374 static struct rcu_torture_ops rcu_ops = {
375 .ttype = RCU_FLAVOR,
376 .init = rcu_sync_torture_init,
377 .readlock = rcu_torture_read_lock,
378 .read_delay = rcu_read_delay,
379 .readunlock = rcu_torture_read_unlock,
380 .completed = rcu_torture_completed,
381 .deferred_free = rcu_torture_deferred_free,
382 .sync = synchronize_rcu,
383 .exp_sync = synchronize_rcu_expedited,
384 .get_state = get_state_synchronize_rcu,
385 .cond_sync = cond_synchronize_rcu,
386 .call = call_rcu,
387 .cb_barrier = rcu_barrier,
388 .fqs = rcu_force_quiescent_state,
389 .stats = NULL,
390 .irq_capable = 1,
391 .can_boost = rcu_can_boost(),
392 .name = "rcu"
393 };
394
395 /*
396 * Definitions for rcu_bh torture testing.
397 */
398
rcu_bh_torture_read_lock(void)399 static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
400 {
401 rcu_read_lock_bh();
402 return 0;
403 }
404
rcu_bh_torture_read_unlock(int idx)405 static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
406 {
407 rcu_read_unlock_bh();
408 }
409
rcu_bh_torture_completed(void)410 static int rcu_bh_torture_completed(void)
411 {
412 return rcu_batches_completed_bh();
413 }
414
rcu_bh_torture_deferred_free(struct rcu_torture * p)415 static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
416 {
417 call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
418 }
419
420 static struct rcu_torture_ops rcu_bh_ops = {
421 .ttype = RCU_BH_FLAVOR,
422 .init = rcu_sync_torture_init,
423 .readlock = rcu_bh_torture_read_lock,
424 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
425 .readunlock = rcu_bh_torture_read_unlock,
426 .completed = rcu_bh_torture_completed,
427 .deferred_free = rcu_bh_torture_deferred_free,
428 .sync = synchronize_rcu_bh,
429 .exp_sync = synchronize_rcu_bh_expedited,
430 .call = call_rcu_bh,
431 .cb_barrier = rcu_barrier_bh,
432 .fqs = rcu_bh_force_quiescent_state,
433 .stats = NULL,
434 .irq_capable = 1,
435 .name = "rcu_bh"
436 };
437
438 /*
439 * Don't even think about trying any of these in real life!!!
440 * The names includes "busted", and they really means it!
441 * The only purpose of these functions is to provide a buggy RCU
442 * implementation to make sure that rcutorture correctly emits
443 * buggy-RCU error messages.
444 */
rcu_busted_torture_deferred_free(struct rcu_torture * p)445 static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
446 {
447 /* This is a deliberate bug for testing purposes only! */
448 rcu_torture_cb(&p->rtort_rcu);
449 }
450
synchronize_rcu_busted(void)451 static void synchronize_rcu_busted(void)
452 {
453 /* This is a deliberate bug for testing purposes only! */
454 }
455
456 static void
call_rcu_busted(struct rcu_head * head,void (* func)(struct rcu_head * rcu))457 call_rcu_busted(struct rcu_head *head, void (*func)(struct rcu_head *rcu))
458 {
459 /* This is a deliberate bug for testing purposes only! */
460 func(head);
461 }
462
463 static struct rcu_torture_ops rcu_busted_ops = {
464 .ttype = INVALID_RCU_FLAVOR,
465 .init = rcu_sync_torture_init,
466 .readlock = rcu_torture_read_lock,
467 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
468 .readunlock = rcu_torture_read_unlock,
469 .completed = rcu_no_completed,
470 .deferred_free = rcu_busted_torture_deferred_free,
471 .sync = synchronize_rcu_busted,
472 .exp_sync = synchronize_rcu_busted,
473 .call = call_rcu_busted,
474 .cb_barrier = NULL,
475 .fqs = NULL,
476 .stats = NULL,
477 .irq_capable = 1,
478 .name = "rcu_busted"
479 };
480
481 /*
482 * Definitions for srcu torture testing.
483 */
484
485 DEFINE_STATIC_SRCU(srcu_ctl);
486
srcu_torture_read_lock(void)487 static int srcu_torture_read_lock(void) __acquires(&srcu_ctl)
488 {
489 return srcu_read_lock(&srcu_ctl);
490 }
491
srcu_read_delay(struct torture_random_state * rrsp)492 static void srcu_read_delay(struct torture_random_state *rrsp)
493 {
494 long delay;
495 const long uspertick = 1000000 / HZ;
496 const long longdelay = 10;
497
498 /* We want there to be long-running readers, but not all the time. */
499
500 delay = torture_random(rrsp) %
501 (nrealreaders * 2 * longdelay * uspertick);
502 if (!delay)
503 schedule_timeout_interruptible(longdelay);
504 else
505 rcu_read_delay(rrsp);
506 }
507
srcu_torture_read_unlock(int idx)508 static void srcu_torture_read_unlock(int idx) __releases(&srcu_ctl)
509 {
510 srcu_read_unlock(&srcu_ctl, idx);
511 }
512
srcu_torture_completed(void)513 static int srcu_torture_completed(void)
514 {
515 return srcu_batches_completed(&srcu_ctl);
516 }
517
srcu_torture_deferred_free(struct rcu_torture * rp)518 static void srcu_torture_deferred_free(struct rcu_torture *rp)
519 {
520 call_srcu(&srcu_ctl, &rp->rtort_rcu, rcu_torture_cb);
521 }
522
srcu_torture_synchronize(void)523 static void srcu_torture_synchronize(void)
524 {
525 synchronize_srcu(&srcu_ctl);
526 }
527
srcu_torture_call(struct rcu_head * head,void (* func)(struct rcu_head * head))528 static void srcu_torture_call(struct rcu_head *head,
529 void (*func)(struct rcu_head *head))
530 {
531 call_srcu(&srcu_ctl, head, func);
532 }
533
srcu_torture_barrier(void)534 static void srcu_torture_barrier(void)
535 {
536 srcu_barrier(&srcu_ctl);
537 }
538
srcu_torture_stats(void)539 static void srcu_torture_stats(void)
540 {
541 int cpu;
542 int idx = srcu_ctl.completed & 0x1;
543
544 pr_alert("%s%s per-CPU(idx=%d):",
545 torture_type, TORTURE_FLAG, idx);
546 for_each_possible_cpu(cpu) {
547 long c0, c1;
548
549 c0 = (long)per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx];
550 c1 = (long)per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx];
551 pr_cont(" %d(%ld,%ld)", cpu, c0, c1);
552 }
553 pr_cont("\n");
554 }
555
srcu_torture_synchronize_expedited(void)556 static void srcu_torture_synchronize_expedited(void)
557 {
558 synchronize_srcu_expedited(&srcu_ctl);
559 }
560
561 static struct rcu_torture_ops srcu_ops = {
562 .ttype = SRCU_FLAVOR,
563 .init = rcu_sync_torture_init,
564 .readlock = srcu_torture_read_lock,
565 .read_delay = srcu_read_delay,
566 .readunlock = srcu_torture_read_unlock,
567 .completed = srcu_torture_completed,
568 .deferred_free = srcu_torture_deferred_free,
569 .sync = srcu_torture_synchronize,
570 .exp_sync = srcu_torture_synchronize_expedited,
571 .call = srcu_torture_call,
572 .cb_barrier = srcu_torture_barrier,
573 .stats = srcu_torture_stats,
574 .name = "srcu"
575 };
576
577 /*
578 * Definitions for sched torture testing.
579 */
580
sched_torture_read_lock(void)581 static int sched_torture_read_lock(void)
582 {
583 preempt_disable();
584 return 0;
585 }
586
sched_torture_read_unlock(int idx)587 static void sched_torture_read_unlock(int idx)
588 {
589 preempt_enable();
590 }
591
rcu_sched_torture_deferred_free(struct rcu_torture * p)592 static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
593 {
594 call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
595 }
596
597 static struct rcu_torture_ops sched_ops = {
598 .ttype = RCU_SCHED_FLAVOR,
599 .init = rcu_sync_torture_init,
600 .readlock = sched_torture_read_lock,
601 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
602 .readunlock = sched_torture_read_unlock,
603 .completed = rcu_no_completed,
604 .deferred_free = rcu_sched_torture_deferred_free,
605 .sync = synchronize_sched,
606 .exp_sync = synchronize_sched_expedited,
607 .call = call_rcu_sched,
608 .cb_barrier = rcu_barrier_sched,
609 .fqs = rcu_sched_force_quiescent_state,
610 .stats = NULL,
611 .irq_capable = 1,
612 .name = "sched"
613 };
614
615 #ifdef CONFIG_TASKS_RCU
616
617 /*
618 * Definitions for RCU-tasks torture testing.
619 */
620
tasks_torture_read_lock(void)621 static int tasks_torture_read_lock(void)
622 {
623 return 0;
624 }
625
tasks_torture_read_unlock(int idx)626 static void tasks_torture_read_unlock(int idx)
627 {
628 }
629
rcu_tasks_torture_deferred_free(struct rcu_torture * p)630 static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
631 {
632 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
633 }
634
635 static struct rcu_torture_ops tasks_ops = {
636 .ttype = RCU_TASKS_FLAVOR,
637 .init = rcu_sync_torture_init,
638 .readlock = tasks_torture_read_lock,
639 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
640 .readunlock = tasks_torture_read_unlock,
641 .completed = rcu_no_completed,
642 .deferred_free = rcu_tasks_torture_deferred_free,
643 .sync = synchronize_rcu_tasks,
644 .exp_sync = synchronize_rcu_tasks,
645 .call = call_rcu_tasks,
646 .cb_barrier = rcu_barrier_tasks,
647 .fqs = NULL,
648 .stats = NULL,
649 .irq_capable = 1,
650 .name = "tasks"
651 };
652
653 #define RCUTORTURE_TASKS_OPS &tasks_ops,
654
655 #else /* #ifdef CONFIG_TASKS_RCU */
656
657 #define RCUTORTURE_TASKS_OPS
658
659 #endif /* #else #ifdef CONFIG_TASKS_RCU */
660
661 /*
662 * RCU torture priority-boost testing. Runs one real-time thread per
663 * CPU for moderate bursts, repeatedly registering RCU callbacks and
664 * spinning waiting for them to be invoked. If a given callback takes
665 * too long to be invoked, we assume that priority inversion has occurred.
666 */
667
668 struct rcu_boost_inflight {
669 struct rcu_head rcu;
670 int inflight;
671 };
672
rcu_torture_boost_cb(struct rcu_head * head)673 static void rcu_torture_boost_cb(struct rcu_head *head)
674 {
675 struct rcu_boost_inflight *rbip =
676 container_of(head, struct rcu_boost_inflight, rcu);
677
678 smp_mb(); /* Ensure RCU-core accesses precede clearing ->inflight */
679 rbip->inflight = 0;
680 }
681
rcu_torture_boost(void * arg)682 static int rcu_torture_boost(void *arg)
683 {
684 unsigned long call_rcu_time;
685 unsigned long endtime;
686 unsigned long oldstarttime;
687 struct rcu_boost_inflight rbi = { .inflight = 0 };
688 struct sched_param sp;
689
690 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
691
692 /* Set real-time priority. */
693 sp.sched_priority = 1;
694 if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
695 VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!");
696 n_rcu_torture_boost_rterror++;
697 }
698
699 init_rcu_head_on_stack(&rbi.rcu);
700 /* Each pass through the following loop does one boost-test cycle. */
701 do {
702 /* Wait for the next test interval. */
703 oldstarttime = boost_starttime;
704 while (ULONG_CMP_LT(jiffies, oldstarttime)) {
705 schedule_timeout_interruptible(oldstarttime - jiffies);
706 stutter_wait("rcu_torture_boost");
707 if (torture_must_stop())
708 goto checkwait;
709 }
710
711 /* Do one boost-test interval. */
712 endtime = oldstarttime + test_boost_duration * HZ;
713 call_rcu_time = jiffies;
714 while (ULONG_CMP_LT(jiffies, endtime)) {
715 /* If we don't have a callback in flight, post one. */
716 if (!rbi.inflight) {
717 smp_mb(); /* RCU core before ->inflight = 1. */
718 rbi.inflight = 1;
719 call_rcu(&rbi.rcu, rcu_torture_boost_cb);
720 if (jiffies - call_rcu_time >
721 test_boost_duration * HZ - HZ / 2) {
722 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
723 n_rcu_torture_boost_failure++;
724 }
725 call_rcu_time = jiffies;
726 }
727 cond_resched_rcu_qs();
728 stutter_wait("rcu_torture_boost");
729 if (torture_must_stop())
730 goto checkwait;
731 }
732
733 /*
734 * Set the start time of the next test interval.
735 * Yes, this is vulnerable to long delays, but such
736 * delays simply cause a false negative for the next
737 * interval. Besides, we are running at RT priority,
738 * so delays should be relatively rare.
739 */
740 while (oldstarttime == boost_starttime &&
741 !kthread_should_stop()) {
742 if (mutex_trylock(&boost_mutex)) {
743 boost_starttime = jiffies +
744 test_boost_interval * HZ;
745 n_rcu_torture_boosts++;
746 mutex_unlock(&boost_mutex);
747 break;
748 }
749 schedule_timeout_uninterruptible(1);
750 }
751
752 /* Go do the stutter. */
753 checkwait: stutter_wait("rcu_torture_boost");
754 } while (!torture_must_stop());
755
756 /* Clean up and exit. */
757 while (!kthread_should_stop() || rbi.inflight) {
758 torture_shutdown_absorb("rcu_torture_boost");
759 schedule_timeout_uninterruptible(1);
760 }
761 smp_mb(); /* order accesses to ->inflight before stack-frame death. */
762 destroy_rcu_head_on_stack(&rbi.rcu);
763 torture_kthread_stopping("rcu_torture_boost");
764 return 0;
765 }
766
rcu_torture_cbflood_cb(struct rcu_head * rhp)767 static void rcu_torture_cbflood_cb(struct rcu_head *rhp)
768 {
769 }
770
771 /*
772 * RCU torture callback-flood kthread. Repeatedly induces bursts of calls
773 * to call_rcu() or analogous, increasing the probability of occurrence
774 * of callback-overflow corner cases.
775 */
776 static int
rcu_torture_cbflood(void * arg)777 rcu_torture_cbflood(void *arg)
778 {
779 int err = 1;
780 int i;
781 int j;
782 struct rcu_head *rhp;
783
784 if (cbflood_n_per_burst > 0 &&
785 cbflood_inter_holdoff > 0 &&
786 cbflood_intra_holdoff > 0 &&
787 cur_ops->call &&
788 cur_ops->cb_barrier) {
789 rhp = vmalloc(sizeof(*rhp) *
790 cbflood_n_burst * cbflood_n_per_burst);
791 err = !rhp;
792 }
793 if (err) {
794 VERBOSE_TOROUT_STRING("rcu_torture_cbflood disabled: Bad args or OOM");
795 while (!torture_must_stop())
796 schedule_timeout_interruptible(HZ);
797 return 0;
798 }
799 VERBOSE_TOROUT_STRING("rcu_torture_cbflood task started");
800 do {
801 schedule_timeout_interruptible(cbflood_inter_holdoff);
802 atomic_long_inc(&n_cbfloods);
803 WARN_ON(signal_pending(current));
804 for (i = 0; i < cbflood_n_burst; i++) {
805 for (j = 0; j < cbflood_n_per_burst; j++) {
806 cur_ops->call(&rhp[i * cbflood_n_per_burst + j],
807 rcu_torture_cbflood_cb);
808 }
809 schedule_timeout_interruptible(cbflood_intra_holdoff);
810 WARN_ON(signal_pending(current));
811 }
812 cur_ops->cb_barrier();
813 stutter_wait("rcu_torture_cbflood");
814 } while (!torture_must_stop());
815 torture_kthread_stopping("rcu_torture_cbflood");
816 return 0;
817 }
818
819 /*
820 * RCU torture force-quiescent-state kthread. Repeatedly induces
821 * bursts of calls to force_quiescent_state(), increasing the probability
822 * of occurrence of some important types of race conditions.
823 */
824 static int
rcu_torture_fqs(void * arg)825 rcu_torture_fqs(void *arg)
826 {
827 unsigned long fqs_resume_time;
828 int fqs_burst_remaining;
829
830 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
831 do {
832 fqs_resume_time = jiffies + fqs_stutter * HZ;
833 while (ULONG_CMP_LT(jiffies, fqs_resume_time) &&
834 !kthread_should_stop()) {
835 schedule_timeout_interruptible(1);
836 }
837 fqs_burst_remaining = fqs_duration;
838 while (fqs_burst_remaining > 0 &&
839 !kthread_should_stop()) {
840 cur_ops->fqs();
841 udelay(fqs_holdoff);
842 fqs_burst_remaining -= fqs_holdoff;
843 }
844 stutter_wait("rcu_torture_fqs");
845 } while (!torture_must_stop());
846 torture_kthread_stopping("rcu_torture_fqs");
847 return 0;
848 }
849
850 /*
851 * RCU torture writer kthread. Repeatedly substitutes a new structure
852 * for that pointed to by rcu_torture_current, freeing the old structure
853 * after a series of grace periods (the "pipeline").
854 */
855 static int
rcu_torture_writer(void * arg)856 rcu_torture_writer(void *arg)
857 {
858 unsigned long gp_snap;
859 bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal;
860 bool gp_sync1 = gp_sync;
861 int i;
862 struct rcu_torture *rp;
863 struct rcu_torture *old_rp;
864 static DEFINE_TORTURE_RANDOM(rand);
865 int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC,
866 RTWS_COND_GET, RTWS_SYNC };
867 int nsynctypes = 0;
868
869 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
870
871 /* Initialize synctype[] array. If none set, take default. */
872 if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync)
873 gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true;
874 if (gp_cond1 && cur_ops->get_state && cur_ops->cond_sync)
875 synctype[nsynctypes++] = RTWS_COND_GET;
876 else if (gp_cond && (!cur_ops->get_state || !cur_ops->cond_sync))
877 pr_alert("rcu_torture_writer: gp_cond without primitives.\n");
878 if (gp_exp1 && cur_ops->exp_sync)
879 synctype[nsynctypes++] = RTWS_EXP_SYNC;
880 else if (gp_exp && !cur_ops->exp_sync)
881 pr_alert("rcu_torture_writer: gp_exp without primitives.\n");
882 if (gp_normal1 && cur_ops->deferred_free)
883 synctype[nsynctypes++] = RTWS_DEF_FREE;
884 else if (gp_normal && !cur_ops->deferred_free)
885 pr_alert("rcu_torture_writer: gp_normal without primitives.\n");
886 if (gp_sync1 && cur_ops->sync)
887 synctype[nsynctypes++] = RTWS_SYNC;
888 else if (gp_sync && !cur_ops->sync)
889 pr_alert("rcu_torture_writer: gp_sync without primitives.\n");
890 if (WARN_ONCE(nsynctypes == 0,
891 "rcu_torture_writer: No update-side primitives.\n")) {
892 /*
893 * No updates primitives, so don't try updating.
894 * The resulting test won't be testing much, hence the
895 * above WARN_ONCE().
896 */
897 rcu_torture_writer_state = RTWS_STOPPING;
898 torture_kthread_stopping("rcu_torture_writer");
899 }
900
901 do {
902 rcu_torture_writer_state = RTWS_FIXED_DELAY;
903 schedule_timeout_uninterruptible(1);
904 rp = rcu_torture_alloc();
905 if (rp == NULL)
906 continue;
907 rp->rtort_pipe_count = 0;
908 rcu_torture_writer_state = RTWS_DELAY;
909 udelay(torture_random(&rand) & 0x3ff);
910 rcu_torture_writer_state = RTWS_REPLACE;
911 old_rp = rcu_dereference_check(rcu_torture_current,
912 current == writer_task);
913 rp->rtort_mbtest = 1;
914 rcu_assign_pointer(rcu_torture_current, rp);
915 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
916 if (old_rp) {
917 i = old_rp->rtort_pipe_count;
918 if (i > RCU_TORTURE_PIPE_LEN)
919 i = RCU_TORTURE_PIPE_LEN;
920 atomic_inc(&rcu_torture_wcount[i]);
921 old_rp->rtort_pipe_count++;
922 switch (synctype[torture_random(&rand) % nsynctypes]) {
923 case RTWS_DEF_FREE:
924 rcu_torture_writer_state = RTWS_DEF_FREE;
925 cur_ops->deferred_free(old_rp);
926 break;
927 case RTWS_EXP_SYNC:
928 rcu_torture_writer_state = RTWS_EXP_SYNC;
929 cur_ops->exp_sync();
930 rcu_torture_pipe_update(old_rp);
931 break;
932 case RTWS_COND_GET:
933 rcu_torture_writer_state = RTWS_COND_GET;
934 gp_snap = cur_ops->get_state();
935 i = torture_random(&rand) % 16;
936 if (i != 0)
937 schedule_timeout_interruptible(i);
938 udelay(torture_random(&rand) % 1000);
939 rcu_torture_writer_state = RTWS_COND_SYNC;
940 cur_ops->cond_sync(gp_snap);
941 rcu_torture_pipe_update(old_rp);
942 break;
943 case RTWS_SYNC:
944 rcu_torture_writer_state = RTWS_SYNC;
945 cur_ops->sync();
946 rcu_torture_pipe_update(old_rp);
947 break;
948 default:
949 WARN_ON_ONCE(1);
950 break;
951 }
952 }
953 rcutorture_record_progress(++rcu_torture_current_version);
954 rcu_torture_writer_state = RTWS_STUTTER;
955 stutter_wait("rcu_torture_writer");
956 } while (!torture_must_stop());
957 rcu_torture_writer_state = RTWS_STOPPING;
958 torture_kthread_stopping("rcu_torture_writer");
959 return 0;
960 }
961
962 /*
963 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
964 * delay between calls.
965 */
966 static int
rcu_torture_fakewriter(void * arg)967 rcu_torture_fakewriter(void *arg)
968 {
969 DEFINE_TORTURE_RANDOM(rand);
970
971 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
972 set_user_nice(current, MAX_NICE);
973
974 do {
975 schedule_timeout_uninterruptible(1 + torture_random(&rand)%10);
976 udelay(torture_random(&rand) & 0x3ff);
977 if (cur_ops->cb_barrier != NULL &&
978 torture_random(&rand) % (nfakewriters * 8) == 0) {
979 cur_ops->cb_barrier();
980 } else if (gp_normal == gp_exp) {
981 if (torture_random(&rand) & 0x80)
982 cur_ops->sync();
983 else
984 cur_ops->exp_sync();
985 } else if (gp_normal) {
986 cur_ops->sync();
987 } else {
988 cur_ops->exp_sync();
989 }
990 stutter_wait("rcu_torture_fakewriter");
991 } while (!torture_must_stop());
992
993 torture_kthread_stopping("rcu_torture_fakewriter");
994 return 0;
995 }
996
rcutorture_trace_dump(void)997 static void rcutorture_trace_dump(void)
998 {
999 static atomic_t beenhere = ATOMIC_INIT(0);
1000
1001 if (atomic_read(&beenhere))
1002 return;
1003 if (atomic_xchg(&beenhere, 1) != 0)
1004 return;
1005 ftrace_dump(DUMP_ALL);
1006 }
1007
1008 /*
1009 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
1010 * incrementing the corresponding element of the pipeline array. The
1011 * counter in the element should never be greater than 1, otherwise, the
1012 * RCU implementation is broken.
1013 */
rcu_torture_timer(unsigned long unused)1014 static void rcu_torture_timer(unsigned long unused)
1015 {
1016 int idx;
1017 int completed;
1018 int completed_end;
1019 static DEFINE_TORTURE_RANDOM(rand);
1020 static DEFINE_SPINLOCK(rand_lock);
1021 struct rcu_torture *p;
1022 int pipe_count;
1023 unsigned long long ts;
1024
1025 idx = cur_ops->readlock();
1026 completed = cur_ops->completed();
1027 ts = rcu_trace_clock_local();
1028 p = rcu_dereference_check(rcu_torture_current,
1029 rcu_read_lock_bh_held() ||
1030 rcu_read_lock_sched_held() ||
1031 srcu_read_lock_held(&srcu_ctl));
1032 if (p == NULL) {
1033 /* Leave because rcu_torture_writer is not yet underway */
1034 cur_ops->readunlock(idx);
1035 return;
1036 }
1037 if (p->rtort_mbtest == 0)
1038 atomic_inc(&n_rcu_torture_mberror);
1039 spin_lock(&rand_lock);
1040 cur_ops->read_delay(&rand);
1041 n_rcu_torture_timers++;
1042 spin_unlock(&rand_lock);
1043 preempt_disable();
1044 pipe_count = p->rtort_pipe_count;
1045 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1046 /* Should not happen, but... */
1047 pipe_count = RCU_TORTURE_PIPE_LEN;
1048 }
1049 completed_end = cur_ops->completed();
1050 if (pipe_count > 1) {
1051 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, ts,
1052 completed, completed_end);
1053 rcutorture_trace_dump();
1054 }
1055 __this_cpu_inc(rcu_torture_count[pipe_count]);
1056 completed = completed_end - completed;
1057 if (completed > RCU_TORTURE_PIPE_LEN) {
1058 /* Should not happen, but... */
1059 completed = RCU_TORTURE_PIPE_LEN;
1060 }
1061 __this_cpu_inc(rcu_torture_batch[completed]);
1062 preempt_enable();
1063 cur_ops->readunlock(idx);
1064 }
1065
1066 /*
1067 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
1068 * incrementing the corresponding element of the pipeline array. The
1069 * counter in the element should never be greater than 1, otherwise, the
1070 * RCU implementation is broken.
1071 */
1072 static int
rcu_torture_reader(void * arg)1073 rcu_torture_reader(void *arg)
1074 {
1075 int completed;
1076 int completed_end;
1077 int idx;
1078 DEFINE_TORTURE_RANDOM(rand);
1079 struct rcu_torture *p;
1080 int pipe_count;
1081 struct timer_list t;
1082 unsigned long long ts;
1083
1084 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
1085 set_user_nice(current, MAX_NICE);
1086 if (irqreader && cur_ops->irq_capable)
1087 setup_timer_on_stack(&t, rcu_torture_timer, 0);
1088
1089 do {
1090 if (irqreader && cur_ops->irq_capable) {
1091 if (!timer_pending(&t))
1092 mod_timer(&t, jiffies + 1);
1093 }
1094 idx = cur_ops->readlock();
1095 completed = cur_ops->completed();
1096 ts = rcu_trace_clock_local();
1097 p = rcu_dereference_check(rcu_torture_current,
1098 rcu_read_lock_bh_held() ||
1099 rcu_read_lock_sched_held() ||
1100 srcu_read_lock_held(&srcu_ctl));
1101 if (p == NULL) {
1102 /* Wait for rcu_torture_writer to get underway */
1103 cur_ops->readunlock(idx);
1104 schedule_timeout_interruptible(HZ);
1105 continue;
1106 }
1107 if (p->rtort_mbtest == 0)
1108 atomic_inc(&n_rcu_torture_mberror);
1109 cur_ops->read_delay(&rand);
1110 preempt_disable();
1111 pipe_count = p->rtort_pipe_count;
1112 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1113 /* Should not happen, but... */
1114 pipe_count = RCU_TORTURE_PIPE_LEN;
1115 }
1116 completed_end = cur_ops->completed();
1117 if (pipe_count > 1) {
1118 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
1119 ts, completed, completed_end);
1120 rcutorture_trace_dump();
1121 }
1122 __this_cpu_inc(rcu_torture_count[pipe_count]);
1123 completed = completed_end - completed;
1124 if (completed > RCU_TORTURE_PIPE_LEN) {
1125 /* Should not happen, but... */
1126 completed = RCU_TORTURE_PIPE_LEN;
1127 }
1128 __this_cpu_inc(rcu_torture_batch[completed]);
1129 preempt_enable();
1130 cur_ops->readunlock(idx);
1131 cond_resched_rcu_qs();
1132 stutter_wait("rcu_torture_reader");
1133 } while (!torture_must_stop());
1134 if (irqreader && cur_ops->irq_capable) {
1135 del_timer_sync(&t);
1136 destroy_timer_on_stack(&t);
1137 }
1138 torture_kthread_stopping("rcu_torture_reader");
1139 return 0;
1140 }
1141
1142 /*
1143 * Print torture statistics. Caller must ensure that there is only
1144 * one call to this function at a given time!!! This is normally
1145 * accomplished by relying on the module system to only have one copy
1146 * of the module loaded, and then by giving the rcu_torture_stats
1147 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1148 * thread is not running).
1149 */
1150 static void
rcu_torture_stats_print(void)1151 rcu_torture_stats_print(void)
1152 {
1153 int cpu;
1154 int i;
1155 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1156 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1157 static unsigned long rtcv_snap = ULONG_MAX;
1158
1159 for_each_possible_cpu(cpu) {
1160 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1161 pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
1162 batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
1163 }
1164 }
1165 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
1166 if (pipesummary[i] != 0)
1167 break;
1168 }
1169
1170 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1171 pr_cont("rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
1172 rcu_torture_current,
1173 rcu_torture_current_version,
1174 list_empty(&rcu_torture_freelist),
1175 atomic_read(&n_rcu_torture_alloc),
1176 atomic_read(&n_rcu_torture_alloc_fail),
1177 atomic_read(&n_rcu_torture_free));
1178 pr_cont("rtmbe: %d rtbke: %ld rtbre: %ld ",
1179 atomic_read(&n_rcu_torture_mberror),
1180 n_rcu_torture_boost_ktrerror,
1181 n_rcu_torture_boost_rterror);
1182 pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
1183 n_rcu_torture_boost_failure,
1184 n_rcu_torture_boosts,
1185 n_rcu_torture_timers);
1186 torture_onoff_stats();
1187 pr_cont("barrier: %ld/%ld:%ld ",
1188 n_barrier_successes,
1189 n_barrier_attempts,
1190 n_rcu_torture_barrier_error);
1191 pr_cont("cbflood: %ld\n", atomic_long_read(&n_cbfloods));
1192
1193 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1194 if (atomic_read(&n_rcu_torture_mberror) != 0 ||
1195 n_rcu_torture_barrier_error != 0 ||
1196 n_rcu_torture_boost_ktrerror != 0 ||
1197 n_rcu_torture_boost_rterror != 0 ||
1198 n_rcu_torture_boost_failure != 0 ||
1199 i > 1) {
1200 pr_cont("%s", "!!! ");
1201 atomic_inc(&n_rcu_torture_error);
1202 WARN_ON_ONCE(1);
1203 }
1204 pr_cont("Reader Pipe: ");
1205 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1206 pr_cont(" %ld", pipesummary[i]);
1207 pr_cont("\n");
1208
1209 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1210 pr_cont("Reader Batch: ");
1211 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1212 pr_cont(" %ld", batchsummary[i]);
1213 pr_cont("\n");
1214
1215 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1216 pr_cont("Free-Block Circulation: ");
1217 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1218 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
1219 }
1220 pr_cont("\n");
1221
1222 if (cur_ops->stats)
1223 cur_ops->stats();
1224 if (rtcv_snap == rcu_torture_current_version &&
1225 rcu_torture_current != NULL) {
1226 int __maybe_unused flags;
1227 unsigned long __maybe_unused gpnum;
1228 unsigned long __maybe_unused completed;
1229
1230 rcutorture_get_gp_data(cur_ops->ttype,
1231 &flags, &gpnum, &completed);
1232 pr_alert("??? Writer stall state %d g%lu c%lu f%#x\n",
1233 rcu_torture_writer_state,
1234 gpnum, completed, flags);
1235 show_rcu_gp_kthreads();
1236 rcutorture_trace_dump();
1237 }
1238 rtcv_snap = rcu_torture_current_version;
1239 }
1240
1241 /*
1242 * Periodically prints torture statistics, if periodic statistics printing
1243 * was specified via the stat_interval module parameter.
1244 */
1245 static int
rcu_torture_stats(void * arg)1246 rcu_torture_stats(void *arg)
1247 {
1248 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1249 do {
1250 schedule_timeout_interruptible(stat_interval * HZ);
1251 rcu_torture_stats_print();
1252 torture_shutdown_absorb("rcu_torture_stats");
1253 } while (!torture_must_stop());
1254 torture_kthread_stopping("rcu_torture_stats");
1255 return 0;
1256 }
1257
1258 static inline void
rcu_torture_print_module_parms(struct rcu_torture_ops * cur_ops,const char * tag)1259 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1260 {
1261 pr_alert("%s" TORTURE_FLAG
1262 "--- %s: nreaders=%d nfakewriters=%d "
1263 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1264 "shuffle_interval=%d stutter=%d irqreader=%d "
1265 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1266 "test_boost=%d/%d test_boost_interval=%d "
1267 "test_boost_duration=%d shutdown_secs=%d "
1268 "stall_cpu=%d stall_cpu_holdoff=%d "
1269 "n_barrier_cbs=%d "
1270 "onoff_interval=%d onoff_holdoff=%d\n",
1271 torture_type, tag, nrealreaders, nfakewriters,
1272 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1273 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1274 test_boost, cur_ops->can_boost,
1275 test_boost_interval, test_boost_duration, shutdown_secs,
1276 stall_cpu, stall_cpu_holdoff,
1277 n_barrier_cbs,
1278 onoff_interval, onoff_holdoff);
1279 }
1280
rcutorture_booster_cleanup(int cpu)1281 static void rcutorture_booster_cleanup(int cpu)
1282 {
1283 struct task_struct *t;
1284
1285 if (boost_tasks[cpu] == NULL)
1286 return;
1287 mutex_lock(&boost_mutex);
1288 t = boost_tasks[cpu];
1289 boost_tasks[cpu] = NULL;
1290 mutex_unlock(&boost_mutex);
1291
1292 /* This must be outside of the mutex, otherwise deadlock! */
1293 torture_stop_kthread(rcu_torture_boost, t);
1294 }
1295
rcutorture_booster_init(int cpu)1296 static int rcutorture_booster_init(int cpu)
1297 {
1298 int retval;
1299
1300 if (boost_tasks[cpu] != NULL)
1301 return 0; /* Already created, nothing more to do. */
1302
1303 /* Don't allow time recalculation while creating a new task. */
1304 mutex_lock(&boost_mutex);
1305 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
1306 boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
1307 cpu_to_node(cpu),
1308 "rcu_torture_boost");
1309 if (IS_ERR(boost_tasks[cpu])) {
1310 retval = PTR_ERR(boost_tasks[cpu]);
1311 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
1312 n_rcu_torture_boost_ktrerror++;
1313 boost_tasks[cpu] = NULL;
1314 mutex_unlock(&boost_mutex);
1315 return retval;
1316 }
1317 kthread_bind(boost_tasks[cpu], cpu);
1318 wake_up_process(boost_tasks[cpu]);
1319 mutex_unlock(&boost_mutex);
1320 return 0;
1321 }
1322
1323 /*
1324 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
1325 * induces a CPU stall for the time specified by stall_cpu.
1326 */
rcu_torture_stall(void * args)1327 static int rcu_torture_stall(void *args)
1328 {
1329 unsigned long stop_at;
1330
1331 VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
1332 if (stall_cpu_holdoff > 0) {
1333 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
1334 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
1335 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
1336 }
1337 if (!kthread_should_stop()) {
1338 stop_at = get_seconds() + stall_cpu;
1339 /* RCU CPU stall is expected behavior in following code. */
1340 pr_alert("rcu_torture_stall start.\n");
1341 rcu_read_lock();
1342 preempt_disable();
1343 while (ULONG_CMP_LT(get_seconds(), stop_at))
1344 continue; /* Induce RCU CPU stall warning. */
1345 preempt_enable();
1346 rcu_read_unlock();
1347 pr_alert("rcu_torture_stall end.\n");
1348 }
1349 torture_shutdown_absorb("rcu_torture_stall");
1350 while (!kthread_should_stop())
1351 schedule_timeout_interruptible(10 * HZ);
1352 return 0;
1353 }
1354
1355 /* Spawn CPU-stall kthread, if stall_cpu specified. */
rcu_torture_stall_init(void)1356 static int __init rcu_torture_stall_init(void)
1357 {
1358 if (stall_cpu <= 0)
1359 return 0;
1360 return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
1361 }
1362
1363 /* Callback function for RCU barrier testing. */
rcu_torture_barrier_cbf(struct rcu_head * rcu)1364 static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
1365 {
1366 atomic_inc(&barrier_cbs_invoked);
1367 }
1368
1369 /* kthread function to register callbacks used to test RCU barriers. */
rcu_torture_barrier_cbs(void * arg)1370 static int rcu_torture_barrier_cbs(void *arg)
1371 {
1372 long myid = (long)arg;
1373 bool lastphase = 0;
1374 bool newphase;
1375 struct rcu_head rcu;
1376
1377 init_rcu_head_on_stack(&rcu);
1378 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
1379 set_user_nice(current, MAX_NICE);
1380 do {
1381 wait_event(barrier_cbs_wq[myid],
1382 (newphase =
1383 ACCESS_ONCE(barrier_phase)) != lastphase ||
1384 torture_must_stop());
1385 lastphase = newphase;
1386 smp_mb(); /* ensure barrier_phase load before ->call(). */
1387 if (torture_must_stop())
1388 break;
1389 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
1390 if (atomic_dec_and_test(&barrier_cbs_count))
1391 wake_up(&barrier_wq);
1392 } while (!torture_must_stop());
1393 if (cur_ops->cb_barrier != NULL)
1394 cur_ops->cb_barrier();
1395 destroy_rcu_head_on_stack(&rcu);
1396 torture_kthread_stopping("rcu_torture_barrier_cbs");
1397 return 0;
1398 }
1399
1400 /* kthread function to drive and coordinate RCU barrier testing. */
rcu_torture_barrier(void * arg)1401 static int rcu_torture_barrier(void *arg)
1402 {
1403 int i;
1404
1405 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
1406 do {
1407 atomic_set(&barrier_cbs_invoked, 0);
1408 atomic_set(&barrier_cbs_count, n_barrier_cbs);
1409 smp_mb(); /* Ensure barrier_phase after prior assignments. */
1410 barrier_phase = !barrier_phase;
1411 for (i = 0; i < n_barrier_cbs; i++)
1412 wake_up(&barrier_cbs_wq[i]);
1413 wait_event(barrier_wq,
1414 atomic_read(&barrier_cbs_count) == 0 ||
1415 torture_must_stop());
1416 if (torture_must_stop())
1417 break;
1418 n_barrier_attempts++;
1419 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
1420 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
1421 n_rcu_torture_barrier_error++;
1422 WARN_ON_ONCE(1);
1423 }
1424 n_barrier_successes++;
1425 schedule_timeout_interruptible(HZ / 10);
1426 } while (!torture_must_stop());
1427 torture_kthread_stopping("rcu_torture_barrier");
1428 return 0;
1429 }
1430
1431 /* Initialize RCU barrier testing. */
rcu_torture_barrier_init(void)1432 static int rcu_torture_barrier_init(void)
1433 {
1434 int i;
1435 int ret;
1436
1437 if (n_barrier_cbs == 0)
1438 return 0;
1439 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
1440 pr_alert("%s" TORTURE_FLAG
1441 " Call or barrier ops missing for %s,\n",
1442 torture_type, cur_ops->name);
1443 pr_alert("%s" TORTURE_FLAG
1444 " RCU barrier testing omitted from run.\n",
1445 torture_type);
1446 return 0;
1447 }
1448 atomic_set(&barrier_cbs_count, 0);
1449 atomic_set(&barrier_cbs_invoked, 0);
1450 barrier_cbs_tasks =
1451 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_tasks[0]),
1452 GFP_KERNEL);
1453 barrier_cbs_wq =
1454 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_wq[0]),
1455 GFP_KERNEL);
1456 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
1457 return -ENOMEM;
1458 for (i = 0; i < n_barrier_cbs; i++) {
1459 init_waitqueue_head(&barrier_cbs_wq[i]);
1460 ret = torture_create_kthread(rcu_torture_barrier_cbs,
1461 (void *)(long)i,
1462 barrier_cbs_tasks[i]);
1463 if (ret)
1464 return ret;
1465 }
1466 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
1467 }
1468
1469 /* Clean up after RCU barrier testing. */
rcu_torture_barrier_cleanup(void)1470 static void rcu_torture_barrier_cleanup(void)
1471 {
1472 int i;
1473
1474 torture_stop_kthread(rcu_torture_barrier, barrier_task);
1475 if (barrier_cbs_tasks != NULL) {
1476 for (i = 0; i < n_barrier_cbs; i++)
1477 torture_stop_kthread(rcu_torture_barrier_cbs,
1478 barrier_cbs_tasks[i]);
1479 kfree(barrier_cbs_tasks);
1480 barrier_cbs_tasks = NULL;
1481 }
1482 if (barrier_cbs_wq != NULL) {
1483 kfree(barrier_cbs_wq);
1484 barrier_cbs_wq = NULL;
1485 }
1486 }
1487
rcutorture_cpu_notify(struct notifier_block * self,unsigned long action,void * hcpu)1488 static int rcutorture_cpu_notify(struct notifier_block *self,
1489 unsigned long action, void *hcpu)
1490 {
1491 long cpu = (long)hcpu;
1492
1493 switch (action) {
1494 case CPU_ONLINE:
1495 case CPU_DOWN_FAILED:
1496 (void)rcutorture_booster_init(cpu);
1497 break;
1498 case CPU_DOWN_PREPARE:
1499 rcutorture_booster_cleanup(cpu);
1500 break;
1501 default:
1502 break;
1503 }
1504 return NOTIFY_OK;
1505 }
1506
1507 static struct notifier_block rcutorture_cpu_nb = {
1508 .notifier_call = rcutorture_cpu_notify,
1509 };
1510
1511 static void
rcu_torture_cleanup(void)1512 rcu_torture_cleanup(void)
1513 {
1514 int i;
1515
1516 rcutorture_record_test_transition();
1517 if (torture_cleanup_begin()) {
1518 if (cur_ops->cb_barrier != NULL)
1519 cur_ops->cb_barrier();
1520 return;
1521 }
1522
1523 rcu_torture_barrier_cleanup();
1524 torture_stop_kthread(rcu_torture_stall, stall_task);
1525 torture_stop_kthread(rcu_torture_writer, writer_task);
1526
1527 if (reader_tasks) {
1528 for (i = 0; i < nrealreaders; i++)
1529 torture_stop_kthread(rcu_torture_reader,
1530 reader_tasks[i]);
1531 kfree(reader_tasks);
1532 }
1533 rcu_torture_current = NULL;
1534
1535 if (fakewriter_tasks) {
1536 for (i = 0; i < nfakewriters; i++) {
1537 torture_stop_kthread(rcu_torture_fakewriter,
1538 fakewriter_tasks[i]);
1539 }
1540 kfree(fakewriter_tasks);
1541 fakewriter_tasks = NULL;
1542 }
1543
1544 torture_stop_kthread(rcu_torture_stats, stats_task);
1545 torture_stop_kthread(rcu_torture_fqs, fqs_task);
1546 for (i = 0; i < ncbflooders; i++)
1547 torture_stop_kthread(rcu_torture_cbflood, cbflood_task[i]);
1548 if ((test_boost == 1 && cur_ops->can_boost) ||
1549 test_boost == 2) {
1550 unregister_cpu_notifier(&rcutorture_cpu_nb);
1551 for_each_possible_cpu(i)
1552 rcutorture_booster_cleanup(i);
1553 }
1554
1555 /* Wait for all RCU callbacks to fire. */
1556
1557 if (cur_ops->cb_barrier != NULL)
1558 cur_ops->cb_barrier();
1559
1560 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
1561
1562 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
1563 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
1564 else if (torture_onoff_failures())
1565 rcu_torture_print_module_parms(cur_ops,
1566 "End of test: RCU_HOTPLUG");
1567 else
1568 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
1569 torture_cleanup_end();
1570 }
1571
1572 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
rcu_torture_leak_cb(struct rcu_head * rhp)1573 static void rcu_torture_leak_cb(struct rcu_head *rhp)
1574 {
1575 }
1576
rcu_torture_err_cb(struct rcu_head * rhp)1577 static void rcu_torture_err_cb(struct rcu_head *rhp)
1578 {
1579 /*
1580 * This -might- happen due to race conditions, but is unlikely.
1581 * The scenario that leads to this happening is that the
1582 * first of the pair of duplicate callbacks is queued,
1583 * someone else starts a grace period that includes that
1584 * callback, then the second of the pair must wait for the
1585 * next grace period. Unlikely, but can happen. If it
1586 * does happen, the debug-objects subsystem won't have splatted.
1587 */
1588 pr_alert("rcutorture: duplicated callback was invoked.\n");
1589 }
1590 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1591
1592 /*
1593 * Verify that double-free causes debug-objects to complain, but only
1594 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
1595 * cannot be carried out.
1596 */
rcu_test_debug_objects(void)1597 static void rcu_test_debug_objects(void)
1598 {
1599 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1600 struct rcu_head rh1;
1601 struct rcu_head rh2;
1602
1603 init_rcu_head_on_stack(&rh1);
1604 init_rcu_head_on_stack(&rh2);
1605 pr_alert("rcutorture: WARN: Duplicate call_rcu() test starting.\n");
1606
1607 /* Try to queue the rh2 pair of callbacks for the same grace period. */
1608 preempt_disable(); /* Prevent preemption from interrupting test. */
1609 rcu_read_lock(); /* Make it impossible to finish a grace period. */
1610 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
1611 local_irq_disable(); /* Make it harder to start a new grace period. */
1612 call_rcu(&rh2, rcu_torture_leak_cb);
1613 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
1614 local_irq_enable();
1615 rcu_read_unlock();
1616 preempt_enable();
1617
1618 /* Wait for them all to get done so we can safely return. */
1619 rcu_barrier();
1620 pr_alert("rcutorture: WARN: Duplicate call_rcu() test complete.\n");
1621 destroy_rcu_head_on_stack(&rh1);
1622 destroy_rcu_head_on_stack(&rh2);
1623 #else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1624 pr_alert("rcutorture: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n");
1625 #endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1626 }
1627
1628 static int __init
rcu_torture_init(void)1629 rcu_torture_init(void)
1630 {
1631 int i;
1632 int cpu;
1633 int firsterr = 0;
1634 static struct rcu_torture_ops *torture_ops[] = {
1635 &rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &sched_ops,
1636 RCUTORTURE_TASKS_OPS
1637 };
1638
1639 if (!torture_init_begin(torture_type, verbose, &torture_runnable))
1640 return -EBUSY;
1641
1642 /* Process args and tell the world that the torturer is on the job. */
1643 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1644 cur_ops = torture_ops[i];
1645 if (strcmp(torture_type, cur_ops->name) == 0)
1646 break;
1647 }
1648 if (i == ARRAY_SIZE(torture_ops)) {
1649 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
1650 torture_type);
1651 pr_alert("rcu-torture types:");
1652 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1653 pr_alert(" %s", torture_ops[i]->name);
1654 pr_alert("\n");
1655 torture_init_end();
1656 return -EINVAL;
1657 }
1658 if (cur_ops->fqs == NULL && fqs_duration != 0) {
1659 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
1660 fqs_duration = 0;
1661 }
1662 if (cur_ops->init)
1663 cur_ops->init(); /* no "goto unwind" prior to this point!!! */
1664
1665 if (nreaders >= 0) {
1666 nrealreaders = nreaders;
1667 } else {
1668 nrealreaders = num_online_cpus() - 1;
1669 if (nrealreaders <= 0)
1670 nrealreaders = 1;
1671 }
1672 rcu_torture_print_module_parms(cur_ops, "Start of test");
1673
1674 /* Set up the freelist. */
1675
1676 INIT_LIST_HEAD(&rcu_torture_freelist);
1677 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1678 rcu_tortures[i].rtort_mbtest = 0;
1679 list_add_tail(&rcu_tortures[i].rtort_free,
1680 &rcu_torture_freelist);
1681 }
1682
1683 /* Initialize the statistics so that each run gets its own numbers. */
1684
1685 rcu_torture_current = NULL;
1686 rcu_torture_current_version = 0;
1687 atomic_set(&n_rcu_torture_alloc, 0);
1688 atomic_set(&n_rcu_torture_alloc_fail, 0);
1689 atomic_set(&n_rcu_torture_free, 0);
1690 atomic_set(&n_rcu_torture_mberror, 0);
1691 atomic_set(&n_rcu_torture_error, 0);
1692 n_rcu_torture_barrier_error = 0;
1693 n_rcu_torture_boost_ktrerror = 0;
1694 n_rcu_torture_boost_rterror = 0;
1695 n_rcu_torture_boost_failure = 0;
1696 n_rcu_torture_boosts = 0;
1697 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1698 atomic_set(&rcu_torture_wcount[i], 0);
1699 for_each_possible_cpu(cpu) {
1700 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1701 per_cpu(rcu_torture_count, cpu)[i] = 0;
1702 per_cpu(rcu_torture_batch, cpu)[i] = 0;
1703 }
1704 }
1705
1706 /* Start up the kthreads. */
1707
1708 firsterr = torture_create_kthread(rcu_torture_writer, NULL,
1709 writer_task);
1710 if (firsterr)
1711 goto unwind;
1712 fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]),
1713 GFP_KERNEL);
1714 if (fakewriter_tasks == NULL) {
1715 VERBOSE_TOROUT_ERRSTRING("out of memory");
1716 firsterr = -ENOMEM;
1717 goto unwind;
1718 }
1719 for (i = 0; i < nfakewriters; i++) {
1720 firsterr = torture_create_kthread(rcu_torture_fakewriter,
1721 NULL, fakewriter_tasks[i]);
1722 if (firsterr)
1723 goto unwind;
1724 }
1725 reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
1726 GFP_KERNEL);
1727 if (reader_tasks == NULL) {
1728 VERBOSE_TOROUT_ERRSTRING("out of memory");
1729 firsterr = -ENOMEM;
1730 goto unwind;
1731 }
1732 for (i = 0; i < nrealreaders; i++) {
1733 firsterr = torture_create_kthread(rcu_torture_reader, NULL,
1734 reader_tasks[i]);
1735 if (firsterr)
1736 goto unwind;
1737 }
1738 if (stat_interval > 0) {
1739 firsterr = torture_create_kthread(rcu_torture_stats, NULL,
1740 stats_task);
1741 if (firsterr)
1742 goto unwind;
1743 }
1744 if (test_no_idle_hz) {
1745 firsterr = torture_shuffle_init(shuffle_interval * HZ);
1746 if (firsterr)
1747 goto unwind;
1748 }
1749 if (stutter < 0)
1750 stutter = 0;
1751 if (stutter) {
1752 firsterr = torture_stutter_init(stutter * HZ);
1753 if (firsterr)
1754 goto unwind;
1755 }
1756 if (fqs_duration < 0)
1757 fqs_duration = 0;
1758 if (fqs_duration) {
1759 /* Create the fqs thread */
1760 firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
1761 fqs_task);
1762 if (firsterr)
1763 goto unwind;
1764 }
1765 if (test_boost_interval < 1)
1766 test_boost_interval = 1;
1767 if (test_boost_duration < 2)
1768 test_boost_duration = 2;
1769 if ((test_boost == 1 && cur_ops->can_boost) ||
1770 test_boost == 2) {
1771
1772 boost_starttime = jiffies + test_boost_interval * HZ;
1773 register_cpu_notifier(&rcutorture_cpu_nb);
1774 for_each_possible_cpu(i) {
1775 if (cpu_is_offline(i))
1776 continue; /* Heuristic: CPU can go offline. */
1777 firsterr = rcutorture_booster_init(i);
1778 if (firsterr)
1779 goto unwind;
1780 }
1781 }
1782 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
1783 if (firsterr)
1784 goto unwind;
1785 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval * HZ);
1786 if (firsterr)
1787 goto unwind;
1788 firsterr = rcu_torture_stall_init();
1789 if (firsterr)
1790 goto unwind;
1791 firsterr = rcu_torture_barrier_init();
1792 if (firsterr)
1793 goto unwind;
1794 if (object_debug)
1795 rcu_test_debug_objects();
1796 if (cbflood_n_burst > 0) {
1797 /* Create the cbflood threads */
1798 ncbflooders = (num_online_cpus() + 3) / 4;
1799 cbflood_task = kcalloc(ncbflooders, sizeof(*cbflood_task),
1800 GFP_KERNEL);
1801 if (!cbflood_task) {
1802 VERBOSE_TOROUT_ERRSTRING("out of memory");
1803 firsterr = -ENOMEM;
1804 goto unwind;
1805 }
1806 for (i = 0; i < ncbflooders; i++) {
1807 firsterr = torture_create_kthread(rcu_torture_cbflood,
1808 NULL,
1809 cbflood_task[i]);
1810 if (firsterr)
1811 goto unwind;
1812 }
1813 }
1814 rcutorture_record_test_transition();
1815 torture_init_end();
1816 return 0;
1817
1818 unwind:
1819 torture_init_end();
1820 rcu_torture_cleanup();
1821 return firsterr;
1822 }
1823
1824 module_init(rcu_torture_init);
1825 module_exit(rcu_torture_cleanup);
1826