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Merge tag 'rxrpc-20140126' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells...
[deliverable/linux.git] / kernel / rcu / torture.c
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, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 *
18 * Copyright (C) IBM Corporation, 2005, 2006
19 *
20 * Authors: Paul E. McKenney <paulmck@us.ibm.com>
21 * Josh Triplett <josh@freedesktop.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
52 MODULE_LICENSE("GPL");
53 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@freedesktop.org>");
54
55 MODULE_ALIAS("rcutorture");
56 #ifdef MODULE_PARAM_PREFIX
57 #undef MODULE_PARAM_PREFIX
58 #endif
59 #define MODULE_PARAM_PREFIX "rcutorture."
60
61 static int fqs_duration;
62 module_param(fqs_duration, int, 0444);
63 MODULE_PARM_DESC(fqs_duration, "Duration of fqs bursts (us), 0 to disable");
64 static int fqs_holdoff;
65 module_param(fqs_holdoff, int, 0444);
66 MODULE_PARM_DESC(fqs_holdoff, "Holdoff time within fqs bursts (us)");
67 static int fqs_stutter = 3;
68 module_param(fqs_stutter, int, 0444);
69 MODULE_PARM_DESC(fqs_stutter, "Wait time between fqs bursts (s)");
70 static bool gp_exp;
71 module_param(gp_exp, bool, 0444);
72 MODULE_PARM_DESC(gp_exp, "Use expedited GP wait primitives");
73 static bool gp_normal;
74 module_param(gp_normal, bool, 0444);
75 MODULE_PARM_DESC(gp_normal, "Use normal (non-expedited) GP wait primitives");
76 static int irqreader = 1;
77 module_param(irqreader, int, 0444);
78 MODULE_PARM_DESC(irqreader, "Allow RCU readers from irq handlers");
79 static int n_barrier_cbs;
80 module_param(n_barrier_cbs, int, 0444);
81 MODULE_PARM_DESC(n_barrier_cbs, "# of callbacks/kthreads for barrier testing");
82 static int nfakewriters = 4;
83 module_param(nfakewriters, int, 0444);
84 MODULE_PARM_DESC(nfakewriters, "Number of RCU fake writer threads");
85 static int nreaders = -1;
86 module_param(nreaders, int, 0444);
87 MODULE_PARM_DESC(nreaders, "Number of RCU reader threads");
88 static int object_debug;
89 module_param(object_debug, int, 0444);
90 MODULE_PARM_DESC(object_debug, "Enable debug-object double call_rcu() testing");
91 static int onoff_holdoff;
92 module_param(onoff_holdoff, int, 0444);
93 MODULE_PARM_DESC(onoff_holdoff, "Time after boot before CPU hotplugs (s)");
94 static int onoff_interval;
95 module_param(onoff_interval, int, 0444);
96 MODULE_PARM_DESC(onoff_interval, "Time between CPU hotplugs (s), 0=disable");
97 static int shuffle_interval = 3;
98 module_param(shuffle_interval, int, 0444);
99 MODULE_PARM_DESC(shuffle_interval, "Number of seconds between shuffles");
100 static int shutdown_secs;
101 module_param(shutdown_secs, int, 0444);
102 MODULE_PARM_DESC(shutdown_secs, "Shutdown time (s), <= zero to disable.");
103 static int stall_cpu;
104 module_param(stall_cpu, int, 0444);
105 MODULE_PARM_DESC(stall_cpu, "Stall duration (s), zero to disable.");
106 static int stall_cpu_holdoff = 10;
107 module_param(stall_cpu_holdoff, int, 0444);
108 MODULE_PARM_DESC(stall_cpu_holdoff, "Time to wait before starting stall (s).");
109 static int stat_interval = 60;
110 module_param(stat_interval, int, 0644);
111 MODULE_PARM_DESC(stat_interval, "Number of seconds between stats printk()s");
112 static int stutter = 5;
113 module_param(stutter, int, 0444);
114 MODULE_PARM_DESC(stutter, "Number of seconds to run/halt test");
115 static int test_boost = 1;
116 module_param(test_boost, int, 0444);
117 MODULE_PARM_DESC(test_boost, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
118 static int test_boost_duration = 4;
119 module_param(test_boost_duration, int, 0444);
120 MODULE_PARM_DESC(test_boost_duration, "Duration of each boost test, seconds.");
121 static int test_boost_interval = 7;
122 module_param(test_boost_interval, int, 0444);
123 MODULE_PARM_DESC(test_boost_interval, "Interval between boost tests, seconds.");
124 static bool test_no_idle_hz = true;
125 module_param(test_no_idle_hz, bool, 0444);
126 MODULE_PARM_DESC(test_no_idle_hz, "Test support for tickless idle CPUs");
127 static char *torture_type = "rcu";
128 module_param(torture_type, charp, 0444);
129 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, ...)");
130 static bool verbose;
131 module_param(verbose, bool, 0444);
132 MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s");
133
134 #define TORTURE_FLAG "-torture:"
135 #define PRINTK_STRING(s) \
136 do { pr_alert("%s" TORTURE_FLAG s "\n", torture_type); } while (0)
137 #define VERBOSE_PRINTK_STRING(s) \
138 do { if (verbose) pr_alert("%s" TORTURE_FLAG s "\n", torture_type); } while (0)
139 #define VERBOSE_PRINTK_ERRSTRING(s) \
140 do { if (verbose) pr_alert("%s" TORTURE_FLAG "!!! " s "\n", torture_type); } while (0)
141
142 static int nrealreaders;
143 static struct task_struct *writer_task;
144 static struct task_struct **fakewriter_tasks;
145 static struct task_struct **reader_tasks;
146 static struct task_struct *stats_task;
147 static struct task_struct *shuffler_task;
148 static struct task_struct *stutter_task;
149 static struct task_struct *fqs_task;
150 static struct task_struct *boost_tasks[NR_CPUS];
151 static struct task_struct *shutdown_task;
152 #ifdef CONFIG_HOTPLUG_CPU
153 static struct task_struct *onoff_task;
154 #endif /* #ifdef CONFIG_HOTPLUG_CPU */
155 static struct task_struct *stall_task;
156 static struct task_struct **barrier_cbs_tasks;
157 static struct task_struct *barrier_task;
158
159 #define RCU_TORTURE_PIPE_LEN 10
160
161 struct rcu_torture {
162 struct rcu_head rtort_rcu;
163 int rtort_pipe_count;
164 struct list_head rtort_free;
165 int rtort_mbtest;
166 };
167
168 static LIST_HEAD(rcu_torture_freelist);
169 static struct rcu_torture __rcu *rcu_torture_current;
170 static unsigned long rcu_torture_current_version;
171 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
172 static DEFINE_SPINLOCK(rcu_torture_lock);
173 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) =
174 { 0 };
175 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) =
176 { 0 };
177 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
178 static atomic_t n_rcu_torture_alloc;
179 static atomic_t n_rcu_torture_alloc_fail;
180 static atomic_t n_rcu_torture_free;
181 static atomic_t n_rcu_torture_mberror;
182 static atomic_t n_rcu_torture_error;
183 static long n_rcu_torture_barrier_error;
184 static long n_rcu_torture_boost_ktrerror;
185 static long n_rcu_torture_boost_rterror;
186 static long n_rcu_torture_boost_failure;
187 static long n_rcu_torture_boosts;
188 static long n_rcu_torture_timers;
189 static long n_offline_attempts;
190 static long n_offline_successes;
191 static unsigned long sum_offline;
192 static int min_offline = -1;
193 static int max_offline;
194 static long n_online_attempts;
195 static long n_online_successes;
196 static unsigned long sum_online;
197 static int min_online = -1;
198 static int max_online;
199 static long n_barrier_attempts;
200 static long n_barrier_successes;
201 static struct list_head rcu_torture_removed;
202 static cpumask_var_t shuffle_tmp_mask;
203
204 static int stutter_pause_test;
205
206 #if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
207 #define RCUTORTURE_RUNNABLE_INIT 1
208 #else
209 #define RCUTORTURE_RUNNABLE_INIT 0
210 #endif
211 int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT;
212 module_param(rcutorture_runnable, int, 0444);
213 MODULE_PARM_DESC(rcutorture_runnable, "Start rcutorture at boot");
214
215 #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
216 #define rcu_can_boost() 1
217 #else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
218 #define rcu_can_boost() 0
219 #endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
220
221 #ifdef CONFIG_RCU_TRACE
222 static u64 notrace rcu_trace_clock_local(void)
223 {
224 u64 ts = trace_clock_local();
225 unsigned long __maybe_unused ts_rem = do_div(ts, NSEC_PER_USEC);
226 return ts;
227 }
228 #else /* #ifdef CONFIG_RCU_TRACE */
229 static u64 notrace rcu_trace_clock_local(void)
230 {
231 return 0ULL;
232 }
233 #endif /* #else #ifdef CONFIG_RCU_TRACE */
234
235 static unsigned long shutdown_time; /* jiffies to system shutdown. */
236 static unsigned long boost_starttime; /* jiffies of next boost test start. */
237 DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
238 /* and boost task create/destroy. */
239 static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
240 static bool barrier_phase; /* Test phase. */
241 static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
242 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
243 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
244
245 /* Mediate rmmod and system shutdown. Concurrent rmmod & shutdown illegal! */
246
247 #define FULLSTOP_DONTSTOP 0 /* Normal operation. */
248 #define FULLSTOP_SHUTDOWN 1 /* System shutdown with rcutorture running. */
249 #define FULLSTOP_RMMOD 2 /* Normal rmmod of rcutorture. */
250 static int fullstop = FULLSTOP_RMMOD;
251 /*
252 * Protect fullstop transitions and spawning of kthreads.
253 */
254 static DEFINE_MUTEX(fullstop_mutex);
255
256 /* Forward reference. */
257 static void rcu_torture_cleanup(void);
258
259 /*
260 * Detect and respond to a system shutdown.
261 */
262 static int
263 rcutorture_shutdown_notify(struct notifier_block *unused1,
264 unsigned long unused2, void *unused3)
265 {
266 mutex_lock(&fullstop_mutex);
267 if (fullstop == FULLSTOP_DONTSTOP)
268 fullstop = FULLSTOP_SHUTDOWN;
269 else
270 pr_warn(/* but going down anyway, so... */
271 "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
272 mutex_unlock(&fullstop_mutex);
273 return NOTIFY_DONE;
274 }
275
276 /*
277 * Absorb kthreads into a kernel function that won't return, so that
278 * they won't ever access module text or data again.
279 */
280 static void rcutorture_shutdown_absorb(const char *title)
281 {
282 if (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
283 pr_notice(
284 "rcutorture thread %s parking due to system shutdown\n",
285 title);
286 schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
287 }
288 }
289
290 /*
291 * Allocate an element from the rcu_tortures pool.
292 */
293 static struct rcu_torture *
294 rcu_torture_alloc(void)
295 {
296 struct list_head *p;
297
298 spin_lock_bh(&rcu_torture_lock);
299 if (list_empty(&rcu_torture_freelist)) {
300 atomic_inc(&n_rcu_torture_alloc_fail);
301 spin_unlock_bh(&rcu_torture_lock);
302 return NULL;
303 }
304 atomic_inc(&n_rcu_torture_alloc);
305 p = rcu_torture_freelist.next;
306 list_del_init(p);
307 spin_unlock_bh(&rcu_torture_lock);
308 return container_of(p, struct rcu_torture, rtort_free);
309 }
310
311 /*
312 * Free an element to the rcu_tortures pool.
313 */
314 static void
315 rcu_torture_free(struct rcu_torture *p)
316 {
317 atomic_inc(&n_rcu_torture_free);
318 spin_lock_bh(&rcu_torture_lock);
319 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
320 spin_unlock_bh(&rcu_torture_lock);
321 }
322
323 struct rcu_random_state {
324 unsigned long rrs_state;
325 long rrs_count;
326 };
327
328 #define RCU_RANDOM_MULT 39916801 /* prime */
329 #define RCU_RANDOM_ADD 479001701 /* prime */
330 #define RCU_RANDOM_REFRESH 10000
331
332 #define DEFINE_RCU_RANDOM(name) struct rcu_random_state name = { 0, 0 }
333
334 /*
335 * Crude but fast random-number generator. Uses a linear congruential
336 * generator, with occasional help from cpu_clock().
337 */
338 static unsigned long
339 rcu_random(struct rcu_random_state *rrsp)
340 {
341 if (--rrsp->rrs_count < 0) {
342 rrsp->rrs_state += (unsigned long)local_clock();
343 rrsp->rrs_count = RCU_RANDOM_REFRESH;
344 }
345 rrsp->rrs_state = rrsp->rrs_state * RCU_RANDOM_MULT + RCU_RANDOM_ADD;
346 return swahw32(rrsp->rrs_state);
347 }
348
349 static void
350 rcu_stutter_wait(const char *title)
351 {
352 while (stutter_pause_test || !rcutorture_runnable) {
353 if (rcutorture_runnable)
354 schedule_timeout_interruptible(1);
355 else
356 schedule_timeout_interruptible(round_jiffies_relative(HZ));
357 rcutorture_shutdown_absorb(title);
358 }
359 }
360
361 /*
362 * Operations vector for selecting different types of tests.
363 */
364
365 struct rcu_torture_ops {
366 void (*init)(void);
367 int (*readlock)(void);
368 void (*read_delay)(struct rcu_random_state *rrsp);
369 void (*readunlock)(int idx);
370 int (*completed)(void);
371 void (*deferred_free)(struct rcu_torture *p);
372 void (*sync)(void);
373 void (*exp_sync)(void);
374 void (*call)(struct rcu_head *head, void (*func)(struct rcu_head *rcu));
375 void (*cb_barrier)(void);
376 void (*fqs)(void);
377 void (*stats)(char *page);
378 int irq_capable;
379 int can_boost;
380 const char *name;
381 };
382
383 static struct rcu_torture_ops *cur_ops;
384
385 /*
386 * Definitions for rcu torture testing.
387 */
388
389 static int rcu_torture_read_lock(void) __acquires(RCU)
390 {
391 rcu_read_lock();
392 return 0;
393 }
394
395 static void rcu_read_delay(struct rcu_random_state *rrsp)
396 {
397 const unsigned long shortdelay_us = 200;
398 const unsigned long longdelay_ms = 50;
399
400 /* We want a short delay sometimes to make a reader delay the grace
401 * period, and we want a long delay occasionally to trigger
402 * force_quiescent_state. */
403
404 if (!(rcu_random(rrsp) % (nrealreaders * 2000 * longdelay_ms)))
405 mdelay(longdelay_ms);
406 if (!(rcu_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
407 udelay(shortdelay_us);
408 #ifdef CONFIG_PREEMPT
409 if (!preempt_count() && !(rcu_random(rrsp) % (nrealreaders * 20000)))
410 preempt_schedule(); /* No QS if preempt_disable() in effect */
411 #endif
412 }
413
414 static void rcu_torture_read_unlock(int idx) __releases(RCU)
415 {
416 rcu_read_unlock();
417 }
418
419 static int rcu_torture_completed(void)
420 {
421 return rcu_batches_completed();
422 }
423
424 static void
425 rcu_torture_cb(struct rcu_head *p)
426 {
427 int i;
428 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
429
430 if (fullstop != FULLSTOP_DONTSTOP) {
431 /* Test is ending, just drop callbacks on the floor. */
432 /* The next initialization will pick up the pieces. */
433 return;
434 }
435 i = rp->rtort_pipe_count;
436 if (i > RCU_TORTURE_PIPE_LEN)
437 i = RCU_TORTURE_PIPE_LEN;
438 atomic_inc(&rcu_torture_wcount[i]);
439 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
440 rp->rtort_mbtest = 0;
441 rcu_torture_free(rp);
442 } else {
443 cur_ops->deferred_free(rp);
444 }
445 }
446
447 static int rcu_no_completed(void)
448 {
449 return 0;
450 }
451
452 static void rcu_torture_deferred_free(struct rcu_torture *p)
453 {
454 call_rcu(&p->rtort_rcu, rcu_torture_cb);
455 }
456
457 static void rcu_sync_torture_init(void)
458 {
459 INIT_LIST_HEAD(&rcu_torture_removed);
460 }
461
462 static struct rcu_torture_ops rcu_ops = {
463 .init = rcu_sync_torture_init,
464 .readlock = rcu_torture_read_lock,
465 .read_delay = rcu_read_delay,
466 .readunlock = rcu_torture_read_unlock,
467 .completed = rcu_torture_completed,
468 .deferred_free = rcu_torture_deferred_free,
469 .sync = synchronize_rcu,
470 .exp_sync = synchronize_rcu_expedited,
471 .call = call_rcu,
472 .cb_barrier = rcu_barrier,
473 .fqs = rcu_force_quiescent_state,
474 .stats = NULL,
475 .irq_capable = 1,
476 .can_boost = rcu_can_boost(),
477 .name = "rcu"
478 };
479
480 /*
481 * Definitions for rcu_bh torture testing.
482 */
483
484 static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
485 {
486 rcu_read_lock_bh();
487 return 0;
488 }
489
490 static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
491 {
492 rcu_read_unlock_bh();
493 }
494
495 static int rcu_bh_torture_completed(void)
496 {
497 return rcu_batches_completed_bh();
498 }
499
500 static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
501 {
502 call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
503 }
504
505 static struct rcu_torture_ops rcu_bh_ops = {
506 .init = rcu_sync_torture_init,
507 .readlock = rcu_bh_torture_read_lock,
508 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
509 .readunlock = rcu_bh_torture_read_unlock,
510 .completed = rcu_bh_torture_completed,
511 .deferred_free = rcu_bh_torture_deferred_free,
512 .sync = synchronize_rcu_bh,
513 .exp_sync = synchronize_rcu_bh_expedited,
514 .call = call_rcu_bh,
515 .cb_barrier = rcu_barrier_bh,
516 .fqs = rcu_bh_force_quiescent_state,
517 .stats = NULL,
518 .irq_capable = 1,
519 .name = "rcu_bh"
520 };
521
522 /*
523 * Definitions for srcu torture testing.
524 */
525
526 DEFINE_STATIC_SRCU(srcu_ctl);
527
528 static int srcu_torture_read_lock(void) __acquires(&srcu_ctl)
529 {
530 return srcu_read_lock(&srcu_ctl);
531 }
532
533 static void srcu_read_delay(struct rcu_random_state *rrsp)
534 {
535 long delay;
536 const long uspertick = 1000000 / HZ;
537 const long longdelay = 10;
538
539 /* We want there to be long-running readers, but not all the time. */
540
541 delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay * uspertick);
542 if (!delay)
543 schedule_timeout_interruptible(longdelay);
544 else
545 rcu_read_delay(rrsp);
546 }
547
548 static void srcu_torture_read_unlock(int idx) __releases(&srcu_ctl)
549 {
550 srcu_read_unlock(&srcu_ctl, idx);
551 }
552
553 static int srcu_torture_completed(void)
554 {
555 return srcu_batches_completed(&srcu_ctl);
556 }
557
558 static void srcu_torture_deferred_free(struct rcu_torture *rp)
559 {
560 call_srcu(&srcu_ctl, &rp->rtort_rcu, rcu_torture_cb);
561 }
562
563 static void srcu_torture_synchronize(void)
564 {
565 synchronize_srcu(&srcu_ctl);
566 }
567
568 static void srcu_torture_call(struct rcu_head *head,
569 void (*func)(struct rcu_head *head))
570 {
571 call_srcu(&srcu_ctl, head, func);
572 }
573
574 static void srcu_torture_barrier(void)
575 {
576 srcu_barrier(&srcu_ctl);
577 }
578
579 static void srcu_torture_stats(char *page)
580 {
581 int cpu;
582 int idx = srcu_ctl.completed & 0x1;
583
584 page += sprintf(page, "%s%s per-CPU(idx=%d):",
585 torture_type, TORTURE_FLAG, idx);
586 for_each_possible_cpu(cpu) {
587 page += sprintf(page, " %d(%lu,%lu)", cpu,
588 per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx],
589 per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx]);
590 }
591 sprintf(page, "\n");
592 }
593
594 static void srcu_torture_synchronize_expedited(void)
595 {
596 synchronize_srcu_expedited(&srcu_ctl);
597 }
598
599 static struct rcu_torture_ops srcu_ops = {
600 .init = rcu_sync_torture_init,
601 .readlock = srcu_torture_read_lock,
602 .read_delay = srcu_read_delay,
603 .readunlock = srcu_torture_read_unlock,
604 .completed = srcu_torture_completed,
605 .deferred_free = srcu_torture_deferred_free,
606 .sync = srcu_torture_synchronize,
607 .exp_sync = srcu_torture_synchronize_expedited,
608 .call = srcu_torture_call,
609 .cb_barrier = srcu_torture_barrier,
610 .stats = srcu_torture_stats,
611 .name = "srcu"
612 };
613
614 /*
615 * Definitions for sched torture testing.
616 */
617
618 static int sched_torture_read_lock(void)
619 {
620 preempt_disable();
621 return 0;
622 }
623
624 static void sched_torture_read_unlock(int idx)
625 {
626 preempt_enable();
627 }
628
629 static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
630 {
631 call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
632 }
633
634 static struct rcu_torture_ops sched_ops = {
635 .init = rcu_sync_torture_init,
636 .readlock = sched_torture_read_lock,
637 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
638 .readunlock = sched_torture_read_unlock,
639 .completed = rcu_no_completed,
640 .deferred_free = rcu_sched_torture_deferred_free,
641 .sync = synchronize_sched,
642 .exp_sync = synchronize_sched_expedited,
643 .call = call_rcu_sched,
644 .cb_barrier = rcu_barrier_sched,
645 .fqs = rcu_sched_force_quiescent_state,
646 .stats = NULL,
647 .irq_capable = 1,
648 .name = "sched"
649 };
650
651 /*
652 * RCU torture priority-boost testing. Runs one real-time thread per
653 * CPU for moderate bursts, repeatedly registering RCU callbacks and
654 * spinning waiting for them to be invoked. If a given callback takes
655 * too long to be invoked, we assume that priority inversion has occurred.
656 */
657
658 struct rcu_boost_inflight {
659 struct rcu_head rcu;
660 int inflight;
661 };
662
663 static void rcu_torture_boost_cb(struct rcu_head *head)
664 {
665 struct rcu_boost_inflight *rbip =
666 container_of(head, struct rcu_boost_inflight, rcu);
667
668 smp_mb(); /* Ensure RCU-core accesses precede clearing ->inflight */
669 rbip->inflight = 0;
670 }
671
672 static int rcu_torture_boost(void *arg)
673 {
674 unsigned long call_rcu_time;
675 unsigned long endtime;
676 unsigned long oldstarttime;
677 struct rcu_boost_inflight rbi = { .inflight = 0 };
678 struct sched_param sp;
679
680 VERBOSE_PRINTK_STRING("rcu_torture_boost started");
681
682 /* Set real-time priority. */
683 sp.sched_priority = 1;
684 if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
685 VERBOSE_PRINTK_STRING("rcu_torture_boost RT prio failed!");
686 n_rcu_torture_boost_rterror++;
687 }
688
689 init_rcu_head_on_stack(&rbi.rcu);
690 /* Each pass through the following loop does one boost-test cycle. */
691 do {
692 /* Wait for the next test interval. */
693 oldstarttime = boost_starttime;
694 while (ULONG_CMP_LT(jiffies, oldstarttime)) {
695 schedule_timeout_interruptible(oldstarttime - jiffies);
696 rcu_stutter_wait("rcu_torture_boost");
697 if (kthread_should_stop() ||
698 fullstop != FULLSTOP_DONTSTOP)
699 goto checkwait;
700 }
701
702 /* Do one boost-test interval. */
703 endtime = oldstarttime + test_boost_duration * HZ;
704 call_rcu_time = jiffies;
705 while (ULONG_CMP_LT(jiffies, endtime)) {
706 /* If we don't have a callback in flight, post one. */
707 if (!rbi.inflight) {
708 smp_mb(); /* RCU core before ->inflight = 1. */
709 rbi.inflight = 1;
710 call_rcu(&rbi.rcu, rcu_torture_boost_cb);
711 if (jiffies - call_rcu_time >
712 test_boost_duration * HZ - HZ / 2) {
713 VERBOSE_PRINTK_STRING("rcu_torture_boost boosting failed");
714 n_rcu_torture_boost_failure++;
715 }
716 call_rcu_time = jiffies;
717 }
718 cond_resched();
719 rcu_stutter_wait("rcu_torture_boost");
720 if (kthread_should_stop() ||
721 fullstop != FULLSTOP_DONTSTOP)
722 goto checkwait;
723 }
724
725 /*
726 * Set the start time of the next test interval.
727 * Yes, this is vulnerable to long delays, but such
728 * delays simply cause a false negative for the next
729 * interval. Besides, we are running at RT priority,
730 * so delays should be relatively rare.
731 */
732 while (oldstarttime == boost_starttime &&
733 !kthread_should_stop()) {
734 if (mutex_trylock(&boost_mutex)) {
735 boost_starttime = jiffies +
736 test_boost_interval * HZ;
737 n_rcu_torture_boosts++;
738 mutex_unlock(&boost_mutex);
739 break;
740 }
741 schedule_timeout_uninterruptible(1);
742 }
743
744 /* Go do the stutter. */
745 checkwait: rcu_stutter_wait("rcu_torture_boost");
746 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
747
748 /* Clean up and exit. */
749 VERBOSE_PRINTK_STRING("rcu_torture_boost task stopping");
750 rcutorture_shutdown_absorb("rcu_torture_boost");
751 while (!kthread_should_stop() || rbi.inflight)
752 schedule_timeout_uninterruptible(1);
753 smp_mb(); /* order accesses to ->inflight before stack-frame death. */
754 destroy_rcu_head_on_stack(&rbi.rcu);
755 return 0;
756 }
757
758 /*
759 * RCU torture force-quiescent-state kthread. Repeatedly induces
760 * bursts of calls to force_quiescent_state(), increasing the probability
761 * of occurrence of some important types of race conditions.
762 */
763 static int
764 rcu_torture_fqs(void *arg)
765 {
766 unsigned long fqs_resume_time;
767 int fqs_burst_remaining;
768
769 VERBOSE_PRINTK_STRING("rcu_torture_fqs task started");
770 do {
771 fqs_resume_time = jiffies + fqs_stutter * HZ;
772 while (ULONG_CMP_LT(jiffies, fqs_resume_time) &&
773 !kthread_should_stop()) {
774 schedule_timeout_interruptible(1);
775 }
776 fqs_burst_remaining = fqs_duration;
777 while (fqs_burst_remaining > 0 &&
778 !kthread_should_stop()) {
779 cur_ops->fqs();
780 udelay(fqs_holdoff);
781 fqs_burst_remaining -= fqs_holdoff;
782 }
783 rcu_stutter_wait("rcu_torture_fqs");
784 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
785 VERBOSE_PRINTK_STRING("rcu_torture_fqs task stopping");
786 rcutorture_shutdown_absorb("rcu_torture_fqs");
787 while (!kthread_should_stop())
788 schedule_timeout_uninterruptible(1);
789 return 0;
790 }
791
792 /*
793 * RCU torture writer kthread. Repeatedly substitutes a new structure
794 * for that pointed to by rcu_torture_current, freeing the old structure
795 * after a series of grace periods (the "pipeline").
796 */
797 static int
798 rcu_torture_writer(void *arg)
799 {
800 bool exp;
801 int i;
802 struct rcu_torture *rp;
803 struct rcu_torture *rp1;
804 struct rcu_torture *old_rp;
805 static DEFINE_RCU_RANDOM(rand);
806
807 VERBOSE_PRINTK_STRING("rcu_torture_writer task started");
808 set_user_nice(current, 19);
809
810 do {
811 schedule_timeout_uninterruptible(1);
812 rp = rcu_torture_alloc();
813 if (rp == NULL)
814 continue;
815 rp->rtort_pipe_count = 0;
816 udelay(rcu_random(&rand) & 0x3ff);
817 old_rp = rcu_dereference_check(rcu_torture_current,
818 current == writer_task);
819 rp->rtort_mbtest = 1;
820 rcu_assign_pointer(rcu_torture_current, rp);
821 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
822 if (old_rp) {
823 i = old_rp->rtort_pipe_count;
824 if (i > RCU_TORTURE_PIPE_LEN)
825 i = RCU_TORTURE_PIPE_LEN;
826 atomic_inc(&rcu_torture_wcount[i]);
827 old_rp->rtort_pipe_count++;
828 if (gp_normal == gp_exp)
829 exp = !!(rcu_random(&rand) & 0x80);
830 else
831 exp = gp_exp;
832 if (!exp) {
833 cur_ops->deferred_free(old_rp);
834 } else {
835 cur_ops->exp_sync();
836 list_add(&old_rp->rtort_free,
837 &rcu_torture_removed);
838 list_for_each_entry_safe(rp, rp1,
839 &rcu_torture_removed,
840 rtort_free) {
841 i = rp->rtort_pipe_count;
842 if (i > RCU_TORTURE_PIPE_LEN)
843 i = RCU_TORTURE_PIPE_LEN;
844 atomic_inc(&rcu_torture_wcount[i]);
845 if (++rp->rtort_pipe_count >=
846 RCU_TORTURE_PIPE_LEN) {
847 rp->rtort_mbtest = 0;
848 list_del(&rp->rtort_free);
849 rcu_torture_free(rp);
850 }
851 }
852 }
853 }
854 rcutorture_record_progress(++rcu_torture_current_version);
855 rcu_stutter_wait("rcu_torture_writer");
856 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
857 VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
858 rcutorture_shutdown_absorb("rcu_torture_writer");
859 while (!kthread_should_stop())
860 schedule_timeout_uninterruptible(1);
861 return 0;
862 }
863
864 /*
865 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
866 * delay between calls.
867 */
868 static int
869 rcu_torture_fakewriter(void *arg)
870 {
871 DEFINE_RCU_RANDOM(rand);
872
873 VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started");
874 set_user_nice(current, 19);
875
876 do {
877 schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10);
878 udelay(rcu_random(&rand) & 0x3ff);
879 if (cur_ops->cb_barrier != NULL &&
880 rcu_random(&rand) % (nfakewriters * 8) == 0) {
881 cur_ops->cb_barrier();
882 } else if (gp_normal == gp_exp) {
883 if (rcu_random(&rand) & 0x80)
884 cur_ops->sync();
885 else
886 cur_ops->exp_sync();
887 } else if (gp_normal) {
888 cur_ops->sync();
889 } else {
890 cur_ops->exp_sync();
891 }
892 rcu_stutter_wait("rcu_torture_fakewriter");
893 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
894
895 VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
896 rcutorture_shutdown_absorb("rcu_torture_fakewriter");
897 while (!kthread_should_stop())
898 schedule_timeout_uninterruptible(1);
899 return 0;
900 }
901
902 void rcutorture_trace_dump(void)
903 {
904 static atomic_t beenhere = ATOMIC_INIT(0);
905
906 if (atomic_read(&beenhere))
907 return;
908 if (atomic_xchg(&beenhere, 1) != 0)
909 return;
910 ftrace_dump(DUMP_ALL);
911 }
912
913 /*
914 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
915 * incrementing the corresponding element of the pipeline array. The
916 * counter in the element should never be greater than 1, otherwise, the
917 * RCU implementation is broken.
918 */
919 static void rcu_torture_timer(unsigned long unused)
920 {
921 int idx;
922 int completed;
923 int completed_end;
924 static DEFINE_RCU_RANDOM(rand);
925 static DEFINE_SPINLOCK(rand_lock);
926 struct rcu_torture *p;
927 int pipe_count;
928 unsigned long long ts;
929
930 idx = cur_ops->readlock();
931 completed = cur_ops->completed();
932 ts = rcu_trace_clock_local();
933 p = rcu_dereference_check(rcu_torture_current,
934 rcu_read_lock_bh_held() ||
935 rcu_read_lock_sched_held() ||
936 srcu_read_lock_held(&srcu_ctl));
937 if (p == NULL) {
938 /* Leave because rcu_torture_writer is not yet underway */
939 cur_ops->readunlock(idx);
940 return;
941 }
942 if (p->rtort_mbtest == 0)
943 atomic_inc(&n_rcu_torture_mberror);
944 spin_lock(&rand_lock);
945 cur_ops->read_delay(&rand);
946 n_rcu_torture_timers++;
947 spin_unlock(&rand_lock);
948 preempt_disable();
949 pipe_count = p->rtort_pipe_count;
950 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
951 /* Should not happen, but... */
952 pipe_count = RCU_TORTURE_PIPE_LEN;
953 }
954 completed_end = cur_ops->completed();
955 if (pipe_count > 1) {
956 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, ts,
957 completed, completed_end);
958 rcutorture_trace_dump();
959 }
960 __this_cpu_inc(rcu_torture_count[pipe_count]);
961 completed = completed_end - completed;
962 if (completed > RCU_TORTURE_PIPE_LEN) {
963 /* Should not happen, but... */
964 completed = RCU_TORTURE_PIPE_LEN;
965 }
966 __this_cpu_inc(rcu_torture_batch[completed]);
967 preempt_enable();
968 cur_ops->readunlock(idx);
969 }
970
971 /*
972 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
973 * incrementing the corresponding element of the pipeline array. The
974 * counter in the element should never be greater than 1, otherwise, the
975 * RCU implementation is broken.
976 */
977 static int
978 rcu_torture_reader(void *arg)
979 {
980 int completed;
981 int completed_end;
982 int idx;
983 DEFINE_RCU_RANDOM(rand);
984 struct rcu_torture *p;
985 int pipe_count;
986 struct timer_list t;
987 unsigned long long ts;
988
989 VERBOSE_PRINTK_STRING("rcu_torture_reader task started");
990 set_user_nice(current, 19);
991 if (irqreader && cur_ops->irq_capable)
992 setup_timer_on_stack(&t, rcu_torture_timer, 0);
993
994 do {
995 if (irqreader && cur_ops->irq_capable) {
996 if (!timer_pending(&t))
997 mod_timer(&t, jiffies + 1);
998 }
999 idx = cur_ops->readlock();
1000 completed = cur_ops->completed();
1001 ts = rcu_trace_clock_local();
1002 p = rcu_dereference_check(rcu_torture_current,
1003 rcu_read_lock_bh_held() ||
1004 rcu_read_lock_sched_held() ||
1005 srcu_read_lock_held(&srcu_ctl));
1006 if (p == NULL) {
1007 /* Wait for rcu_torture_writer to get underway */
1008 cur_ops->readunlock(idx);
1009 schedule_timeout_interruptible(HZ);
1010 continue;
1011 }
1012 if (p->rtort_mbtest == 0)
1013 atomic_inc(&n_rcu_torture_mberror);
1014 cur_ops->read_delay(&rand);
1015 preempt_disable();
1016 pipe_count = p->rtort_pipe_count;
1017 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1018 /* Should not happen, but... */
1019 pipe_count = RCU_TORTURE_PIPE_LEN;
1020 }
1021 completed_end = cur_ops->completed();
1022 if (pipe_count > 1) {
1023 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
1024 ts, completed, completed_end);
1025 rcutorture_trace_dump();
1026 }
1027 __this_cpu_inc(rcu_torture_count[pipe_count]);
1028 completed = completed_end - completed;
1029 if (completed > RCU_TORTURE_PIPE_LEN) {
1030 /* Should not happen, but... */
1031 completed = RCU_TORTURE_PIPE_LEN;
1032 }
1033 __this_cpu_inc(rcu_torture_batch[completed]);
1034 preempt_enable();
1035 cur_ops->readunlock(idx);
1036 schedule();
1037 rcu_stutter_wait("rcu_torture_reader");
1038 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
1039 VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
1040 rcutorture_shutdown_absorb("rcu_torture_reader");
1041 if (irqreader && cur_ops->irq_capable)
1042 del_timer_sync(&t);
1043 while (!kthread_should_stop())
1044 schedule_timeout_uninterruptible(1);
1045 return 0;
1046 }
1047
1048 /*
1049 * Create an RCU-torture statistics message in the specified buffer.
1050 */
1051 static void
1052 rcu_torture_printk(char *page)
1053 {
1054 int cpu;
1055 int i;
1056 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1057 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1058
1059 for_each_possible_cpu(cpu) {
1060 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1061 pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
1062 batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
1063 }
1064 }
1065 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
1066 if (pipesummary[i] != 0)
1067 break;
1068 }
1069 page += sprintf(page, "%s%s ", torture_type, TORTURE_FLAG);
1070 page += sprintf(page,
1071 "rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
1072 rcu_torture_current,
1073 rcu_torture_current_version,
1074 list_empty(&rcu_torture_freelist),
1075 atomic_read(&n_rcu_torture_alloc),
1076 atomic_read(&n_rcu_torture_alloc_fail),
1077 atomic_read(&n_rcu_torture_free));
1078 page += sprintf(page, "rtmbe: %d rtbke: %ld rtbre: %ld ",
1079 atomic_read(&n_rcu_torture_mberror),
1080 n_rcu_torture_boost_ktrerror,
1081 n_rcu_torture_boost_rterror);
1082 page += sprintf(page, "rtbf: %ld rtb: %ld nt: %ld ",
1083 n_rcu_torture_boost_failure,
1084 n_rcu_torture_boosts,
1085 n_rcu_torture_timers);
1086 page += sprintf(page,
1087 "onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ",
1088 n_online_successes, n_online_attempts,
1089 n_offline_successes, n_offline_attempts,
1090 min_online, max_online,
1091 min_offline, max_offline,
1092 sum_online, sum_offline, HZ);
1093 page += sprintf(page, "barrier: %ld/%ld:%ld",
1094 n_barrier_successes,
1095 n_barrier_attempts,
1096 n_rcu_torture_barrier_error);
1097 page += sprintf(page, "\n%s%s ", torture_type, TORTURE_FLAG);
1098 if (atomic_read(&n_rcu_torture_mberror) != 0 ||
1099 n_rcu_torture_barrier_error != 0 ||
1100 n_rcu_torture_boost_ktrerror != 0 ||
1101 n_rcu_torture_boost_rterror != 0 ||
1102 n_rcu_torture_boost_failure != 0 ||
1103 i > 1) {
1104 page += sprintf(page, "!!! ");
1105 atomic_inc(&n_rcu_torture_error);
1106 WARN_ON_ONCE(1);
1107 }
1108 page += sprintf(page, "Reader Pipe: ");
1109 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1110 page += sprintf(page, " %ld", pipesummary[i]);
1111 page += sprintf(page, "\n%s%s ", torture_type, TORTURE_FLAG);
1112 page += sprintf(page, "Reader Batch: ");
1113 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1114 page += sprintf(page, " %ld", batchsummary[i]);
1115 page += sprintf(page, "\n%s%s ", torture_type, TORTURE_FLAG);
1116 page += sprintf(page, "Free-Block Circulation: ");
1117 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1118 page += sprintf(page, " %d",
1119 atomic_read(&rcu_torture_wcount[i]));
1120 }
1121 page += sprintf(page, "\n");
1122 if (cur_ops->stats)
1123 cur_ops->stats(page);
1124 }
1125
1126 /*
1127 * Print torture statistics. Caller must ensure that there is only
1128 * one call to this function at a given time!!! This is normally
1129 * accomplished by relying on the module system to only have one copy
1130 * of the module loaded, and then by giving the rcu_torture_stats
1131 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1132 * thread is not running).
1133 */
1134 static void
1135 rcu_torture_stats_print(void)
1136 {
1137 int size = nr_cpu_ids * 200 + 8192;
1138 char *buf;
1139
1140 buf = kmalloc(size, GFP_KERNEL);
1141 if (!buf) {
1142 pr_err("rcu-torture: Out of memory, need: %d", size);
1143 return;
1144 }
1145 rcu_torture_printk(buf);
1146 pr_alert("%s", buf);
1147 kfree(buf);
1148 }
1149
1150 /*
1151 * Periodically prints torture statistics, if periodic statistics printing
1152 * was specified via the stat_interval module parameter.
1153 *
1154 * No need to worry about fullstop here, since this one doesn't reference
1155 * volatile state or register callbacks.
1156 */
1157 static int
1158 rcu_torture_stats(void *arg)
1159 {
1160 VERBOSE_PRINTK_STRING("rcu_torture_stats task started");
1161 do {
1162 schedule_timeout_interruptible(stat_interval * HZ);
1163 rcu_torture_stats_print();
1164 rcutorture_shutdown_absorb("rcu_torture_stats");
1165 } while (!kthread_should_stop());
1166 VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping");
1167 return 0;
1168 }
1169
1170 static int rcu_idle_cpu; /* Force all torture tasks off this CPU */
1171
1172 /* Shuffle tasks such that we allow @rcu_idle_cpu to become idle. A special case
1173 * is when @rcu_idle_cpu = -1, when we allow the tasks to run on all CPUs.
1174 */
1175 static void rcu_torture_shuffle_tasks(void)
1176 {
1177 int i;
1178
1179 cpumask_setall(shuffle_tmp_mask);
1180 get_online_cpus();
1181
1182 /* No point in shuffling if there is only one online CPU (ex: UP) */
1183 if (num_online_cpus() == 1) {
1184 put_online_cpus();
1185 return;
1186 }
1187
1188 if (rcu_idle_cpu != -1)
1189 cpumask_clear_cpu(rcu_idle_cpu, shuffle_tmp_mask);
1190
1191 set_cpus_allowed_ptr(current, shuffle_tmp_mask);
1192
1193 if (reader_tasks) {
1194 for (i = 0; i < nrealreaders; i++)
1195 if (reader_tasks[i])
1196 set_cpus_allowed_ptr(reader_tasks[i],
1197 shuffle_tmp_mask);
1198 }
1199 if (fakewriter_tasks) {
1200 for (i = 0; i < nfakewriters; i++)
1201 if (fakewriter_tasks[i])
1202 set_cpus_allowed_ptr(fakewriter_tasks[i],
1203 shuffle_tmp_mask);
1204 }
1205 if (writer_task)
1206 set_cpus_allowed_ptr(writer_task, shuffle_tmp_mask);
1207 if (stats_task)
1208 set_cpus_allowed_ptr(stats_task, shuffle_tmp_mask);
1209 if (stutter_task)
1210 set_cpus_allowed_ptr(stutter_task, shuffle_tmp_mask);
1211 if (fqs_task)
1212 set_cpus_allowed_ptr(fqs_task, shuffle_tmp_mask);
1213 if (shutdown_task)
1214 set_cpus_allowed_ptr(shutdown_task, shuffle_tmp_mask);
1215 #ifdef CONFIG_HOTPLUG_CPU
1216 if (onoff_task)
1217 set_cpus_allowed_ptr(onoff_task, shuffle_tmp_mask);
1218 #endif /* #ifdef CONFIG_HOTPLUG_CPU */
1219 if (stall_task)
1220 set_cpus_allowed_ptr(stall_task, shuffle_tmp_mask);
1221 if (barrier_cbs_tasks)
1222 for (i = 0; i < n_barrier_cbs; i++)
1223 if (barrier_cbs_tasks[i])
1224 set_cpus_allowed_ptr(barrier_cbs_tasks[i],
1225 shuffle_tmp_mask);
1226 if (barrier_task)
1227 set_cpus_allowed_ptr(barrier_task, shuffle_tmp_mask);
1228
1229 if (rcu_idle_cpu == -1)
1230 rcu_idle_cpu = num_online_cpus() - 1;
1231 else
1232 rcu_idle_cpu--;
1233
1234 put_online_cpus();
1235 }
1236
1237 /* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
1238 * system to become idle at a time and cut off its timer ticks. This is meant
1239 * to test the support for such tickless idle CPU in RCU.
1240 */
1241 static int
1242 rcu_torture_shuffle(void *arg)
1243 {
1244 VERBOSE_PRINTK_STRING("rcu_torture_shuffle task started");
1245 do {
1246 schedule_timeout_interruptible(shuffle_interval * HZ);
1247 rcu_torture_shuffle_tasks();
1248 rcutorture_shutdown_absorb("rcu_torture_shuffle");
1249 } while (!kthread_should_stop());
1250 VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping");
1251 return 0;
1252 }
1253
1254 /* Cause the rcutorture test to "stutter", starting and stopping all
1255 * threads periodically.
1256 */
1257 static int
1258 rcu_torture_stutter(void *arg)
1259 {
1260 VERBOSE_PRINTK_STRING("rcu_torture_stutter task started");
1261 do {
1262 schedule_timeout_interruptible(stutter * HZ);
1263 stutter_pause_test = 1;
1264 if (!kthread_should_stop())
1265 schedule_timeout_interruptible(stutter * HZ);
1266 stutter_pause_test = 0;
1267 rcutorture_shutdown_absorb("rcu_torture_stutter");
1268 } while (!kthread_should_stop());
1269 VERBOSE_PRINTK_STRING("rcu_torture_stutter task stopping");
1270 return 0;
1271 }
1272
1273 static inline void
1274 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1275 {
1276 pr_alert("%s" TORTURE_FLAG
1277 "--- %s: nreaders=%d nfakewriters=%d "
1278 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1279 "shuffle_interval=%d stutter=%d irqreader=%d "
1280 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1281 "test_boost=%d/%d test_boost_interval=%d "
1282 "test_boost_duration=%d shutdown_secs=%d "
1283 "stall_cpu=%d stall_cpu_holdoff=%d "
1284 "n_barrier_cbs=%d "
1285 "onoff_interval=%d onoff_holdoff=%d\n",
1286 torture_type, tag, nrealreaders, nfakewriters,
1287 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1288 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1289 test_boost, cur_ops->can_boost,
1290 test_boost_interval, test_boost_duration, shutdown_secs,
1291 stall_cpu, stall_cpu_holdoff,
1292 n_barrier_cbs,
1293 onoff_interval, onoff_holdoff);
1294 }
1295
1296 static struct notifier_block rcutorture_shutdown_nb = {
1297 .notifier_call = rcutorture_shutdown_notify,
1298 };
1299
1300 static void rcutorture_booster_cleanup(int cpu)
1301 {
1302 struct task_struct *t;
1303
1304 if (boost_tasks[cpu] == NULL)
1305 return;
1306 mutex_lock(&boost_mutex);
1307 VERBOSE_PRINTK_STRING("Stopping rcu_torture_boost task");
1308 t = boost_tasks[cpu];
1309 boost_tasks[cpu] = NULL;
1310 mutex_unlock(&boost_mutex);
1311
1312 /* This must be outside of the mutex, otherwise deadlock! */
1313 kthread_stop(t);
1314 boost_tasks[cpu] = NULL;
1315 }
1316
1317 static int rcutorture_booster_init(int cpu)
1318 {
1319 int retval;
1320
1321 if (boost_tasks[cpu] != NULL)
1322 return 0; /* Already created, nothing more to do. */
1323
1324 /* Don't allow time recalculation while creating a new task. */
1325 mutex_lock(&boost_mutex);
1326 VERBOSE_PRINTK_STRING("Creating rcu_torture_boost task");
1327 boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
1328 cpu_to_node(cpu),
1329 "rcu_torture_boost");
1330 if (IS_ERR(boost_tasks[cpu])) {
1331 retval = PTR_ERR(boost_tasks[cpu]);
1332 VERBOSE_PRINTK_STRING("rcu_torture_boost task create failed");
1333 n_rcu_torture_boost_ktrerror++;
1334 boost_tasks[cpu] = NULL;
1335 mutex_unlock(&boost_mutex);
1336 return retval;
1337 }
1338 kthread_bind(boost_tasks[cpu], cpu);
1339 wake_up_process(boost_tasks[cpu]);
1340 mutex_unlock(&boost_mutex);
1341 return 0;
1342 }
1343
1344 /*
1345 * Cause the rcutorture test to shutdown the system after the test has
1346 * run for the time specified by the shutdown_secs module parameter.
1347 */
1348 static int
1349 rcu_torture_shutdown(void *arg)
1350 {
1351 long delta;
1352 unsigned long jiffies_snap;
1353
1354 VERBOSE_PRINTK_STRING("rcu_torture_shutdown task started");
1355 jiffies_snap = ACCESS_ONCE(jiffies);
1356 while (ULONG_CMP_LT(jiffies_snap, shutdown_time) &&
1357 !kthread_should_stop()) {
1358 delta = shutdown_time - jiffies_snap;
1359 if (verbose)
1360 pr_alert("%s" TORTURE_FLAG
1361 "rcu_torture_shutdown task: %lu jiffies remaining\n",
1362 torture_type, delta);
1363 schedule_timeout_interruptible(delta);
1364 jiffies_snap = ACCESS_ONCE(jiffies);
1365 }
1366 if (kthread_should_stop()) {
1367 VERBOSE_PRINTK_STRING("rcu_torture_shutdown task stopping");
1368 return 0;
1369 }
1370
1371 /* OK, shut down the system. */
1372
1373 VERBOSE_PRINTK_STRING("rcu_torture_shutdown task shutting down system");
1374 shutdown_task = NULL; /* Avoid self-kill deadlock. */
1375 rcu_torture_cleanup(); /* Get the success/failure message. */
1376 kernel_power_off(); /* Shut down the system. */
1377 return 0;
1378 }
1379
1380 #ifdef CONFIG_HOTPLUG_CPU
1381
1382 /*
1383 * Execute random CPU-hotplug operations at the interval specified
1384 * by the onoff_interval.
1385 */
1386 static int
1387 rcu_torture_onoff(void *arg)
1388 {
1389 int cpu;
1390 unsigned long delta;
1391 int maxcpu = -1;
1392 DEFINE_RCU_RANDOM(rand);
1393 int ret;
1394 unsigned long starttime;
1395
1396 VERBOSE_PRINTK_STRING("rcu_torture_onoff task started");
1397 for_each_online_cpu(cpu)
1398 maxcpu = cpu;
1399 WARN_ON(maxcpu < 0);
1400 if (onoff_holdoff > 0) {
1401 VERBOSE_PRINTK_STRING("rcu_torture_onoff begin holdoff");
1402 schedule_timeout_interruptible(onoff_holdoff * HZ);
1403 VERBOSE_PRINTK_STRING("rcu_torture_onoff end holdoff");
1404 }
1405 while (!kthread_should_stop()) {
1406 cpu = (rcu_random(&rand) >> 4) % (maxcpu + 1);
1407 if (cpu_online(cpu) && cpu_is_hotpluggable(cpu)) {
1408 if (verbose)
1409 pr_alert("%s" TORTURE_FLAG
1410 "rcu_torture_onoff task: offlining %d\n",
1411 torture_type, cpu);
1412 starttime = jiffies;
1413 n_offline_attempts++;
1414 ret = cpu_down(cpu);
1415 if (ret) {
1416 if (verbose)
1417 pr_alert("%s" TORTURE_FLAG
1418 "rcu_torture_onoff task: offline %d failed: errno %d\n",
1419 torture_type, cpu, ret);
1420 } else {
1421 if (verbose)
1422 pr_alert("%s" TORTURE_FLAG
1423 "rcu_torture_onoff task: offlined %d\n",
1424 torture_type, cpu);
1425 n_offline_successes++;
1426 delta = jiffies - starttime;
1427 sum_offline += delta;
1428 if (min_offline < 0) {
1429 min_offline = delta;
1430 max_offline = delta;
1431 }
1432 if (min_offline > delta)
1433 min_offline = delta;
1434 if (max_offline < delta)
1435 max_offline = delta;
1436 }
1437 } else if (cpu_is_hotpluggable(cpu)) {
1438 if (verbose)
1439 pr_alert("%s" TORTURE_FLAG
1440 "rcu_torture_onoff task: onlining %d\n",
1441 torture_type, cpu);
1442 starttime = jiffies;
1443 n_online_attempts++;
1444 ret = cpu_up(cpu);
1445 if (ret) {
1446 if (verbose)
1447 pr_alert("%s" TORTURE_FLAG
1448 "rcu_torture_onoff task: online %d failed: errno %d\n",
1449 torture_type, cpu, ret);
1450 } else {
1451 if (verbose)
1452 pr_alert("%s" TORTURE_FLAG
1453 "rcu_torture_onoff task: onlined %d\n",
1454 torture_type, cpu);
1455 n_online_successes++;
1456 delta = jiffies - starttime;
1457 sum_online += delta;
1458 if (min_online < 0) {
1459 min_online = delta;
1460 max_online = delta;
1461 }
1462 if (min_online > delta)
1463 min_online = delta;
1464 if (max_online < delta)
1465 max_online = delta;
1466 }
1467 }
1468 schedule_timeout_interruptible(onoff_interval * HZ);
1469 }
1470 VERBOSE_PRINTK_STRING("rcu_torture_onoff task stopping");
1471 return 0;
1472 }
1473
1474 static int
1475 rcu_torture_onoff_init(void)
1476 {
1477 int ret;
1478
1479 if (onoff_interval <= 0)
1480 return 0;
1481 onoff_task = kthread_run(rcu_torture_onoff, NULL, "rcu_torture_onoff");
1482 if (IS_ERR(onoff_task)) {
1483 ret = PTR_ERR(onoff_task);
1484 onoff_task = NULL;
1485 return ret;
1486 }
1487 return 0;
1488 }
1489
1490 static void rcu_torture_onoff_cleanup(void)
1491 {
1492 if (onoff_task == NULL)
1493 return;
1494 VERBOSE_PRINTK_STRING("Stopping rcu_torture_onoff task");
1495 kthread_stop(onoff_task);
1496 onoff_task = NULL;
1497 }
1498
1499 #else /* #ifdef CONFIG_HOTPLUG_CPU */
1500
1501 static int
1502 rcu_torture_onoff_init(void)
1503 {
1504 return 0;
1505 }
1506
1507 static void rcu_torture_onoff_cleanup(void)
1508 {
1509 }
1510
1511 #endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
1512
1513 /*
1514 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
1515 * induces a CPU stall for the time specified by stall_cpu.
1516 */
1517 static int rcu_torture_stall(void *args)
1518 {
1519 unsigned long stop_at;
1520
1521 VERBOSE_PRINTK_STRING("rcu_torture_stall task started");
1522 if (stall_cpu_holdoff > 0) {
1523 VERBOSE_PRINTK_STRING("rcu_torture_stall begin holdoff");
1524 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
1525 VERBOSE_PRINTK_STRING("rcu_torture_stall end holdoff");
1526 }
1527 if (!kthread_should_stop()) {
1528 stop_at = get_seconds() + stall_cpu;
1529 /* RCU CPU stall is expected behavior in following code. */
1530 pr_alert("rcu_torture_stall start.\n");
1531 rcu_read_lock();
1532 preempt_disable();
1533 while (ULONG_CMP_LT(get_seconds(), stop_at))
1534 continue; /* Induce RCU CPU stall warning. */
1535 preempt_enable();
1536 rcu_read_unlock();
1537 pr_alert("rcu_torture_stall end.\n");
1538 }
1539 rcutorture_shutdown_absorb("rcu_torture_stall");
1540 while (!kthread_should_stop())
1541 schedule_timeout_interruptible(10 * HZ);
1542 return 0;
1543 }
1544
1545 /* Spawn CPU-stall kthread, if stall_cpu specified. */
1546 static int __init rcu_torture_stall_init(void)
1547 {
1548 int ret;
1549
1550 if (stall_cpu <= 0)
1551 return 0;
1552 stall_task = kthread_run(rcu_torture_stall, NULL, "rcu_torture_stall");
1553 if (IS_ERR(stall_task)) {
1554 ret = PTR_ERR(stall_task);
1555 stall_task = NULL;
1556 return ret;
1557 }
1558 return 0;
1559 }
1560
1561 /* Clean up after the CPU-stall kthread, if one was spawned. */
1562 static void rcu_torture_stall_cleanup(void)
1563 {
1564 if (stall_task == NULL)
1565 return;
1566 VERBOSE_PRINTK_STRING("Stopping rcu_torture_stall_task.");
1567 kthread_stop(stall_task);
1568 stall_task = NULL;
1569 }
1570
1571 /* Callback function for RCU barrier testing. */
1572 void rcu_torture_barrier_cbf(struct rcu_head *rcu)
1573 {
1574 atomic_inc(&barrier_cbs_invoked);
1575 }
1576
1577 /* kthread function to register callbacks used to test RCU barriers. */
1578 static int rcu_torture_barrier_cbs(void *arg)
1579 {
1580 long myid = (long)arg;
1581 bool lastphase = 0;
1582 bool newphase;
1583 struct rcu_head rcu;
1584
1585 init_rcu_head_on_stack(&rcu);
1586 VERBOSE_PRINTK_STRING("rcu_torture_barrier_cbs task started");
1587 set_user_nice(current, 19);
1588 do {
1589 wait_event(barrier_cbs_wq[myid],
1590 (newphase =
1591 ACCESS_ONCE(barrier_phase)) != lastphase ||
1592 kthread_should_stop() ||
1593 fullstop != FULLSTOP_DONTSTOP);
1594 lastphase = newphase;
1595 smp_mb(); /* ensure barrier_phase load before ->call(). */
1596 if (kthread_should_stop() || fullstop != FULLSTOP_DONTSTOP)
1597 break;
1598 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
1599 if (atomic_dec_and_test(&barrier_cbs_count))
1600 wake_up(&barrier_wq);
1601 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
1602 VERBOSE_PRINTK_STRING("rcu_torture_barrier_cbs task stopping");
1603 rcutorture_shutdown_absorb("rcu_torture_barrier_cbs");
1604 while (!kthread_should_stop())
1605 schedule_timeout_interruptible(1);
1606 cur_ops->cb_barrier();
1607 destroy_rcu_head_on_stack(&rcu);
1608 return 0;
1609 }
1610
1611 /* kthread function to drive and coordinate RCU barrier testing. */
1612 static int rcu_torture_barrier(void *arg)
1613 {
1614 int i;
1615
1616 VERBOSE_PRINTK_STRING("rcu_torture_barrier task starting");
1617 do {
1618 atomic_set(&barrier_cbs_invoked, 0);
1619 atomic_set(&barrier_cbs_count, n_barrier_cbs);
1620 smp_mb(); /* Ensure barrier_phase after prior assignments. */
1621 barrier_phase = !barrier_phase;
1622 for (i = 0; i < n_barrier_cbs; i++)
1623 wake_up(&barrier_cbs_wq[i]);
1624 wait_event(barrier_wq,
1625 atomic_read(&barrier_cbs_count) == 0 ||
1626 kthread_should_stop() ||
1627 fullstop != FULLSTOP_DONTSTOP);
1628 if (kthread_should_stop() || fullstop != FULLSTOP_DONTSTOP)
1629 break;
1630 n_barrier_attempts++;
1631 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
1632 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
1633 n_rcu_torture_barrier_error++;
1634 WARN_ON_ONCE(1);
1635 }
1636 n_barrier_successes++;
1637 schedule_timeout_interruptible(HZ / 10);
1638 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
1639 VERBOSE_PRINTK_STRING("rcu_torture_barrier task stopping");
1640 rcutorture_shutdown_absorb("rcu_torture_barrier");
1641 while (!kthread_should_stop())
1642 schedule_timeout_interruptible(1);
1643 return 0;
1644 }
1645
1646 /* Initialize RCU barrier testing. */
1647 static int rcu_torture_barrier_init(void)
1648 {
1649 int i;
1650 int ret;
1651
1652 if (n_barrier_cbs == 0)
1653 return 0;
1654 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
1655 pr_alert("%s" TORTURE_FLAG
1656 " Call or barrier ops missing for %s,\n",
1657 torture_type, cur_ops->name);
1658 pr_alert("%s" TORTURE_FLAG
1659 " RCU barrier testing omitted from run.\n",
1660 torture_type);
1661 return 0;
1662 }
1663 atomic_set(&barrier_cbs_count, 0);
1664 atomic_set(&barrier_cbs_invoked, 0);
1665 barrier_cbs_tasks =
1666 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_tasks[0]),
1667 GFP_KERNEL);
1668 barrier_cbs_wq =
1669 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_wq[0]),
1670 GFP_KERNEL);
1671 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
1672 return -ENOMEM;
1673 for (i = 0; i < n_barrier_cbs; i++) {
1674 init_waitqueue_head(&barrier_cbs_wq[i]);
1675 barrier_cbs_tasks[i] = kthread_run(rcu_torture_barrier_cbs,
1676 (void *)(long)i,
1677 "rcu_torture_barrier_cbs");
1678 if (IS_ERR(barrier_cbs_tasks[i])) {
1679 ret = PTR_ERR(barrier_cbs_tasks[i]);
1680 VERBOSE_PRINTK_ERRSTRING("Failed to create rcu_torture_barrier_cbs");
1681 barrier_cbs_tasks[i] = NULL;
1682 return ret;
1683 }
1684 }
1685 barrier_task = kthread_run(rcu_torture_barrier, NULL,
1686 "rcu_torture_barrier");
1687 if (IS_ERR(barrier_task)) {
1688 ret = PTR_ERR(barrier_task);
1689 VERBOSE_PRINTK_ERRSTRING("Failed to create rcu_torture_barrier");
1690 barrier_task = NULL;
1691 }
1692 return 0;
1693 }
1694
1695 /* Clean up after RCU barrier testing. */
1696 static void rcu_torture_barrier_cleanup(void)
1697 {
1698 int i;
1699
1700 if (barrier_task != NULL) {
1701 VERBOSE_PRINTK_STRING("Stopping rcu_torture_barrier task");
1702 kthread_stop(barrier_task);
1703 barrier_task = NULL;
1704 }
1705 if (barrier_cbs_tasks != NULL) {
1706 for (i = 0; i < n_barrier_cbs; i++) {
1707 if (barrier_cbs_tasks[i] != NULL) {
1708 VERBOSE_PRINTK_STRING("Stopping rcu_torture_barrier_cbs task");
1709 kthread_stop(barrier_cbs_tasks[i]);
1710 barrier_cbs_tasks[i] = NULL;
1711 }
1712 }
1713 kfree(barrier_cbs_tasks);
1714 barrier_cbs_tasks = NULL;
1715 }
1716 if (barrier_cbs_wq != NULL) {
1717 kfree(barrier_cbs_wq);
1718 barrier_cbs_wq = NULL;
1719 }
1720 }
1721
1722 static int rcutorture_cpu_notify(struct notifier_block *self,
1723 unsigned long action, void *hcpu)
1724 {
1725 long cpu = (long)hcpu;
1726
1727 switch (action) {
1728 case CPU_ONLINE:
1729 case CPU_DOWN_FAILED:
1730 (void)rcutorture_booster_init(cpu);
1731 break;
1732 case CPU_DOWN_PREPARE:
1733 rcutorture_booster_cleanup(cpu);
1734 break;
1735 default:
1736 break;
1737 }
1738 return NOTIFY_OK;
1739 }
1740
1741 static struct notifier_block rcutorture_cpu_nb = {
1742 .notifier_call = rcutorture_cpu_notify,
1743 };
1744
1745 static void
1746 rcu_torture_cleanup(void)
1747 {
1748 int i;
1749
1750 mutex_lock(&fullstop_mutex);
1751 rcutorture_record_test_transition();
1752 if (fullstop == FULLSTOP_SHUTDOWN) {
1753 pr_warn(/* but going down anyway, so... */
1754 "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
1755 mutex_unlock(&fullstop_mutex);
1756 schedule_timeout_uninterruptible(10);
1757 if (cur_ops->cb_barrier != NULL)
1758 cur_ops->cb_barrier();
1759 return;
1760 }
1761 fullstop = FULLSTOP_RMMOD;
1762 mutex_unlock(&fullstop_mutex);
1763 unregister_reboot_notifier(&rcutorture_shutdown_nb);
1764 rcu_torture_barrier_cleanup();
1765 rcu_torture_stall_cleanup();
1766 if (stutter_task) {
1767 VERBOSE_PRINTK_STRING("Stopping rcu_torture_stutter task");
1768 kthread_stop(stutter_task);
1769 }
1770 stutter_task = NULL;
1771 if (shuffler_task) {
1772 VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task");
1773 kthread_stop(shuffler_task);
1774 free_cpumask_var(shuffle_tmp_mask);
1775 }
1776 shuffler_task = NULL;
1777
1778 if (writer_task) {
1779 VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task");
1780 kthread_stop(writer_task);
1781 }
1782 writer_task = NULL;
1783
1784 if (reader_tasks) {
1785 for (i = 0; i < nrealreaders; i++) {
1786 if (reader_tasks[i]) {
1787 VERBOSE_PRINTK_STRING(
1788 "Stopping rcu_torture_reader task");
1789 kthread_stop(reader_tasks[i]);
1790 }
1791 reader_tasks[i] = NULL;
1792 }
1793 kfree(reader_tasks);
1794 reader_tasks = NULL;
1795 }
1796 rcu_torture_current = NULL;
1797
1798 if (fakewriter_tasks) {
1799 for (i = 0; i < nfakewriters; i++) {
1800 if (fakewriter_tasks[i]) {
1801 VERBOSE_PRINTK_STRING(
1802 "Stopping rcu_torture_fakewriter task");
1803 kthread_stop(fakewriter_tasks[i]);
1804 }
1805 fakewriter_tasks[i] = NULL;
1806 }
1807 kfree(fakewriter_tasks);
1808 fakewriter_tasks = NULL;
1809 }
1810
1811 if (stats_task) {
1812 VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task");
1813 kthread_stop(stats_task);
1814 }
1815 stats_task = NULL;
1816
1817 if (fqs_task) {
1818 VERBOSE_PRINTK_STRING("Stopping rcu_torture_fqs task");
1819 kthread_stop(fqs_task);
1820 }
1821 fqs_task = NULL;
1822 if ((test_boost == 1 && cur_ops->can_boost) ||
1823 test_boost == 2) {
1824 unregister_cpu_notifier(&rcutorture_cpu_nb);
1825 for_each_possible_cpu(i)
1826 rcutorture_booster_cleanup(i);
1827 }
1828 if (shutdown_task != NULL) {
1829 VERBOSE_PRINTK_STRING("Stopping rcu_torture_shutdown task");
1830 kthread_stop(shutdown_task);
1831 }
1832 shutdown_task = NULL;
1833 rcu_torture_onoff_cleanup();
1834
1835 /* Wait for all RCU callbacks to fire. */
1836
1837 if (cur_ops->cb_barrier != NULL)
1838 cur_ops->cb_barrier();
1839
1840 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
1841
1842 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
1843 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
1844 else if (n_online_successes != n_online_attempts ||
1845 n_offline_successes != n_offline_attempts)
1846 rcu_torture_print_module_parms(cur_ops,
1847 "End of test: RCU_HOTPLUG");
1848 else
1849 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
1850 }
1851
1852 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1853 static void rcu_torture_leak_cb(struct rcu_head *rhp)
1854 {
1855 }
1856
1857 static void rcu_torture_err_cb(struct rcu_head *rhp)
1858 {
1859 /*
1860 * This -might- happen due to race conditions, but is unlikely.
1861 * The scenario that leads to this happening is that the
1862 * first of the pair of duplicate callbacks is queued,
1863 * someone else starts a grace period that includes that
1864 * callback, then the second of the pair must wait for the
1865 * next grace period. Unlikely, but can happen. If it
1866 * does happen, the debug-objects subsystem won't have splatted.
1867 */
1868 pr_alert("rcutorture: duplicated callback was invoked.\n");
1869 }
1870 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1871
1872 /*
1873 * Verify that double-free causes debug-objects to complain, but only
1874 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
1875 * cannot be carried out.
1876 */
1877 static void rcu_test_debug_objects(void)
1878 {
1879 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1880 struct rcu_head rh1;
1881 struct rcu_head rh2;
1882
1883 init_rcu_head_on_stack(&rh1);
1884 init_rcu_head_on_stack(&rh2);
1885 pr_alert("rcutorture: WARN: Duplicate call_rcu() test starting.\n");
1886
1887 /* Try to queue the rh2 pair of callbacks for the same grace period. */
1888 preempt_disable(); /* Prevent preemption from interrupting test. */
1889 rcu_read_lock(); /* Make it impossible to finish a grace period. */
1890 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
1891 local_irq_disable(); /* Make it harder to start a new grace period. */
1892 call_rcu(&rh2, rcu_torture_leak_cb);
1893 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
1894 local_irq_enable();
1895 rcu_read_unlock();
1896 preempt_enable();
1897
1898 /* Wait for them all to get done so we can safely return. */
1899 rcu_barrier();
1900 pr_alert("rcutorture: WARN: Duplicate call_rcu() test complete.\n");
1901 destroy_rcu_head_on_stack(&rh1);
1902 destroy_rcu_head_on_stack(&rh2);
1903 #else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1904 pr_alert("rcutorture: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n");
1905 #endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1906 }
1907
1908 static int __init
1909 rcu_torture_init(void)
1910 {
1911 int i;
1912 int cpu;
1913 int firsterr = 0;
1914 int retval;
1915 static struct rcu_torture_ops *torture_ops[] = {
1916 &rcu_ops, &rcu_bh_ops, &srcu_ops, &sched_ops,
1917 };
1918
1919 mutex_lock(&fullstop_mutex);
1920
1921 /* Process args and tell the world that the torturer is on the job. */
1922 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1923 cur_ops = torture_ops[i];
1924 if (strcmp(torture_type, cur_ops->name) == 0)
1925 break;
1926 }
1927 if (i == ARRAY_SIZE(torture_ops)) {
1928 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
1929 torture_type);
1930 pr_alert("rcu-torture types:");
1931 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1932 pr_alert(" %s", torture_ops[i]->name);
1933 pr_alert("\n");
1934 mutex_unlock(&fullstop_mutex);
1935 return -EINVAL;
1936 }
1937 if (cur_ops->fqs == NULL && fqs_duration != 0) {
1938 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
1939 fqs_duration = 0;
1940 }
1941 if (cur_ops->init)
1942 cur_ops->init(); /* no "goto unwind" prior to this point!!! */
1943
1944 if (nreaders >= 0)
1945 nrealreaders = nreaders;
1946 else
1947 nrealreaders = 2 * num_online_cpus();
1948 rcu_torture_print_module_parms(cur_ops, "Start of test");
1949 fullstop = FULLSTOP_DONTSTOP;
1950
1951 /* Set up the freelist. */
1952
1953 INIT_LIST_HEAD(&rcu_torture_freelist);
1954 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1955 rcu_tortures[i].rtort_mbtest = 0;
1956 list_add_tail(&rcu_tortures[i].rtort_free,
1957 &rcu_torture_freelist);
1958 }
1959
1960 /* Initialize the statistics so that each run gets its own numbers. */
1961
1962 rcu_torture_current = NULL;
1963 rcu_torture_current_version = 0;
1964 atomic_set(&n_rcu_torture_alloc, 0);
1965 atomic_set(&n_rcu_torture_alloc_fail, 0);
1966 atomic_set(&n_rcu_torture_free, 0);
1967 atomic_set(&n_rcu_torture_mberror, 0);
1968 atomic_set(&n_rcu_torture_error, 0);
1969 n_rcu_torture_barrier_error = 0;
1970 n_rcu_torture_boost_ktrerror = 0;
1971 n_rcu_torture_boost_rterror = 0;
1972 n_rcu_torture_boost_failure = 0;
1973 n_rcu_torture_boosts = 0;
1974 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1975 atomic_set(&rcu_torture_wcount[i], 0);
1976 for_each_possible_cpu(cpu) {
1977 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1978 per_cpu(rcu_torture_count, cpu)[i] = 0;
1979 per_cpu(rcu_torture_batch, cpu)[i] = 0;
1980 }
1981 }
1982
1983 /* Start up the kthreads. */
1984
1985 VERBOSE_PRINTK_STRING("Creating rcu_torture_writer task");
1986 writer_task = kthread_create(rcu_torture_writer, NULL,
1987 "rcu_torture_writer");
1988 if (IS_ERR(writer_task)) {
1989 firsterr = PTR_ERR(writer_task);
1990 VERBOSE_PRINTK_ERRSTRING("Failed to create writer");
1991 writer_task = NULL;
1992 goto unwind;
1993 }
1994 wake_up_process(writer_task);
1995 fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]),
1996 GFP_KERNEL);
1997 if (fakewriter_tasks == NULL) {
1998 VERBOSE_PRINTK_ERRSTRING("out of memory");
1999 firsterr = -ENOMEM;
2000 goto unwind;
2001 }
2002 for (i = 0; i < nfakewriters; i++) {
2003 VERBOSE_PRINTK_STRING("Creating rcu_torture_fakewriter task");
2004 fakewriter_tasks[i] = kthread_run(rcu_torture_fakewriter, NULL,
2005 "rcu_torture_fakewriter");
2006 if (IS_ERR(fakewriter_tasks[i])) {
2007 firsterr = PTR_ERR(fakewriter_tasks[i]);
2008 VERBOSE_PRINTK_ERRSTRING("Failed to create fakewriter");
2009 fakewriter_tasks[i] = NULL;
2010 goto unwind;
2011 }
2012 }
2013 reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
2014 GFP_KERNEL);
2015 if (reader_tasks == NULL) {
2016 VERBOSE_PRINTK_ERRSTRING("out of memory");
2017 firsterr = -ENOMEM;
2018 goto unwind;
2019 }
2020 for (i = 0; i < nrealreaders; i++) {
2021 VERBOSE_PRINTK_STRING("Creating rcu_torture_reader task");
2022 reader_tasks[i] = kthread_run(rcu_torture_reader, NULL,
2023 "rcu_torture_reader");
2024 if (IS_ERR(reader_tasks[i])) {
2025 firsterr = PTR_ERR(reader_tasks[i]);
2026 VERBOSE_PRINTK_ERRSTRING("Failed to create reader");
2027 reader_tasks[i] = NULL;
2028 goto unwind;
2029 }
2030 }
2031 if (stat_interval > 0) {
2032 VERBOSE_PRINTK_STRING("Creating rcu_torture_stats task");
2033 stats_task = kthread_run(rcu_torture_stats, NULL,
2034 "rcu_torture_stats");
2035 if (IS_ERR(stats_task)) {
2036 firsterr = PTR_ERR(stats_task);
2037 VERBOSE_PRINTK_ERRSTRING("Failed to create stats");
2038 stats_task = NULL;
2039 goto unwind;
2040 }
2041 }
2042 if (test_no_idle_hz) {
2043 rcu_idle_cpu = num_online_cpus() - 1;
2044
2045 if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
2046 firsterr = -ENOMEM;
2047 VERBOSE_PRINTK_ERRSTRING("Failed to alloc mask");
2048 goto unwind;
2049 }
2050
2051 /* Create the shuffler thread */
2052 shuffler_task = kthread_run(rcu_torture_shuffle, NULL,
2053 "rcu_torture_shuffle");
2054 if (IS_ERR(shuffler_task)) {
2055 free_cpumask_var(shuffle_tmp_mask);
2056 firsterr = PTR_ERR(shuffler_task);
2057 VERBOSE_PRINTK_ERRSTRING("Failed to create shuffler");
2058 shuffler_task = NULL;
2059 goto unwind;
2060 }
2061 }
2062 if (stutter < 0)
2063 stutter = 0;
2064 if (stutter) {
2065 /* Create the stutter thread */
2066 stutter_task = kthread_run(rcu_torture_stutter, NULL,
2067 "rcu_torture_stutter");
2068 if (IS_ERR(stutter_task)) {
2069 firsterr = PTR_ERR(stutter_task);
2070 VERBOSE_PRINTK_ERRSTRING("Failed to create stutter");
2071 stutter_task = NULL;
2072 goto unwind;
2073 }
2074 }
2075 if (fqs_duration < 0)
2076 fqs_duration = 0;
2077 if (fqs_duration) {
2078 /* Create the stutter thread */
2079 fqs_task = kthread_run(rcu_torture_fqs, NULL,
2080 "rcu_torture_fqs");
2081 if (IS_ERR(fqs_task)) {
2082 firsterr = PTR_ERR(fqs_task);
2083 VERBOSE_PRINTK_ERRSTRING("Failed to create fqs");
2084 fqs_task = NULL;
2085 goto unwind;
2086 }
2087 }
2088 if (test_boost_interval < 1)
2089 test_boost_interval = 1;
2090 if (test_boost_duration < 2)
2091 test_boost_duration = 2;
2092 if ((test_boost == 1 && cur_ops->can_boost) ||
2093 test_boost == 2) {
2094
2095 boost_starttime = jiffies + test_boost_interval * HZ;
2096 register_cpu_notifier(&rcutorture_cpu_nb);
2097 for_each_possible_cpu(i) {
2098 if (cpu_is_offline(i))
2099 continue; /* Heuristic: CPU can go offline. */
2100 retval = rcutorture_booster_init(i);
2101 if (retval < 0) {
2102 firsterr = retval;
2103 goto unwind;
2104 }
2105 }
2106 }
2107 if (shutdown_secs > 0) {
2108 shutdown_time = jiffies + shutdown_secs * HZ;
2109 shutdown_task = kthread_create(rcu_torture_shutdown, NULL,
2110 "rcu_torture_shutdown");
2111 if (IS_ERR(shutdown_task)) {
2112 firsterr = PTR_ERR(shutdown_task);
2113 VERBOSE_PRINTK_ERRSTRING("Failed to create shutdown");
2114 shutdown_task = NULL;
2115 goto unwind;
2116 }
2117 wake_up_process(shutdown_task);
2118 }
2119 i = rcu_torture_onoff_init();
2120 if (i != 0) {
2121 firsterr = i;
2122 goto unwind;
2123 }
2124 register_reboot_notifier(&rcutorture_shutdown_nb);
2125 i = rcu_torture_stall_init();
2126 if (i != 0) {
2127 firsterr = i;
2128 goto unwind;
2129 }
2130 retval = rcu_torture_barrier_init();
2131 if (retval != 0) {
2132 firsterr = retval;
2133 goto unwind;
2134 }
2135 if (object_debug)
2136 rcu_test_debug_objects();
2137 rcutorture_record_test_transition();
2138 mutex_unlock(&fullstop_mutex);
2139 return 0;
2140
2141 unwind:
2142 mutex_unlock(&fullstop_mutex);
2143 rcu_torture_cleanup();
2144 return firsterr;
2145 }
2146
2147 module_init(rcu_torture_init);
2148 module_exit(rcu_torture_cleanup);
Linux kernel - Deliverables
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