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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 <asm/byteorder.h>
50
51MODULE_LICENSE("GPL");
52MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and "
53 "Josh Triplett <josh@freedesktop.org>");
54
55static int nreaders = -1; /* # reader threads, defaults to 2*ncpus */
56static int nfakewriters = 4; /* # fake writer threads */
57static int stat_interval; /* Interval between stats, in seconds. */
58 /* Defaults to "only at end of test". */
59static bool verbose; /* Print more debug info. */
60static bool test_no_idle_hz; /* Test RCU's support for tickless idle CPUs. */
61static int shuffle_interval = 3; /* Interval between shuffles (in sec)*/
62static int stutter = 5; /* Start/stop testing interval (in sec) */
63static int irqreader = 1; /* RCU readers from irq (timers). */
64static int fqs_duration; /* Duration of bursts (us), 0 to disable. */
65static int fqs_holdoff; /* Hold time within burst (us). */
66static int fqs_stutter = 3; /* Wait time between bursts (s). */
67static int n_barrier_cbs; /* Number of callbacks to test RCU barriers. */
68static int onoff_interval; /* Wait time between CPU hotplugs, 0=disable. */
69static int onoff_holdoff; /* Seconds after boot before CPU hotplugs. */
70static int shutdown_secs; /* Shutdown time (s). <=0 for no shutdown. */
71static int stall_cpu; /* CPU-stall duration (s). 0 for no stall. */
72static int stall_cpu_holdoff = 10; /* Time to wait until stall (s). */
73static int test_boost = 1; /* Test RCU prio boost: 0=no, 1=maybe, 2=yes. */
74static int test_boost_interval = 7; /* Interval between boost tests, seconds. */
75static int test_boost_duration = 4; /* Duration of each boost test, seconds. */
76static char *torture_type = "rcu"; /* What RCU implementation to torture. */
77
78module_param(nreaders, int, 0444);
79MODULE_PARM_DESC(nreaders, "Number of RCU reader threads");
80module_param(nfakewriters, int, 0444);
81MODULE_PARM_DESC(nfakewriters, "Number of RCU fake writer threads");
82module_param(stat_interval, int, 0644);
83MODULE_PARM_DESC(stat_interval, "Number of seconds between stats printk()s");
84module_param(verbose, bool, 0444);
85MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s");
86module_param(test_no_idle_hz, bool, 0444);
87MODULE_PARM_DESC(test_no_idle_hz, "Test support for tickless idle CPUs");
88module_param(shuffle_interval, int, 0444);
89MODULE_PARM_DESC(shuffle_interval, "Number of seconds between shuffles");
90module_param(stutter, int, 0444);
91MODULE_PARM_DESC(stutter, "Number of seconds to run/halt test");
92module_param(irqreader, int, 0444);
93MODULE_PARM_DESC(irqreader, "Allow RCU readers from irq handlers");
94module_param(fqs_duration, int, 0444);
95MODULE_PARM_DESC(fqs_duration, "Duration of fqs bursts (us)");
96module_param(fqs_holdoff, int, 0444);
97MODULE_PARM_DESC(fqs_holdoff, "Holdoff time within fqs bursts (us)");
98module_param(fqs_stutter, int, 0444);
99MODULE_PARM_DESC(fqs_stutter, "Wait time between fqs bursts (s)");
100module_param(n_barrier_cbs, int, 0444);
101MODULE_PARM_DESC(n_barrier_cbs, "# of callbacks/kthreads for barrier testing");
102module_param(onoff_interval, int, 0444);
103MODULE_PARM_DESC(onoff_interval, "Time between CPU hotplugs (s), 0=disable");
104module_param(onoff_holdoff, int, 0444);
105MODULE_PARM_DESC(onoff_holdoff, "Time after boot before CPU hotplugs (s)");
106module_param(shutdown_secs, int, 0444);
107MODULE_PARM_DESC(shutdown_secs, "Shutdown time (s), zero to disable.");
108module_param(stall_cpu, int, 0444);
109MODULE_PARM_DESC(stall_cpu, "Stall duration (s), zero to disable.");
110module_param(stall_cpu_holdoff, int, 0444);
111MODULE_PARM_DESC(stall_cpu_holdoff, "Time to wait before starting stall (s).");
112module_param(test_boost, int, 0444);
113MODULE_PARM_DESC(test_boost, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
114module_param(test_boost_interval, int, 0444);
115MODULE_PARM_DESC(test_boost_interval, "Interval between boost tests, seconds.");
116module_param(test_boost_duration, int, 0444);
117MODULE_PARM_DESC(test_boost_duration, "Duration of each boost test, seconds.");
118module_param(torture_type, charp, 0444);
119MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, srcu)");
120
121#define TORTURE_FLAG "-torture:"
122#define PRINTK_STRING(s) \
123 do { printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
124#define VERBOSE_PRINTK_STRING(s) \
125 do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
126#define VERBOSE_PRINTK_ERRSTRING(s) \
127 do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG "!!! " s "\n", torture_type); } while (0)
128
129static char printk_buf[4096];
130
131static int nrealreaders;
132static struct task_struct *writer_task;
133static struct task_struct **fakewriter_tasks;
134static struct task_struct **reader_tasks;
135static struct task_struct *stats_task;
136static struct task_struct *shuffler_task;
137static struct task_struct *stutter_task;
138static struct task_struct *fqs_task;
139static struct task_struct *boost_tasks[NR_CPUS];
140static struct task_struct *shutdown_task;
141#ifdef CONFIG_HOTPLUG_CPU
142static struct task_struct *onoff_task;
143#endif /* #ifdef CONFIG_HOTPLUG_CPU */
144static struct task_struct *stall_task;
145static struct task_struct **barrier_cbs_tasks;
146static struct task_struct *barrier_task;
147
148#define RCU_TORTURE_PIPE_LEN 10
149
150struct rcu_torture {
151 struct rcu_head rtort_rcu;
152 int rtort_pipe_count;
153 struct list_head rtort_free;
154 int rtort_mbtest;
155};
156
157static LIST_HEAD(rcu_torture_freelist);
158static struct rcu_torture __rcu *rcu_torture_current;
159static unsigned long rcu_torture_current_version;
160static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
161static DEFINE_SPINLOCK(rcu_torture_lock);
162static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) =
163 { 0 };
164static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) =
165 { 0 };
166static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
167static atomic_t n_rcu_torture_alloc;
168static atomic_t n_rcu_torture_alloc_fail;
169static atomic_t n_rcu_torture_free;
170static atomic_t n_rcu_torture_mberror;
171static atomic_t n_rcu_torture_error;
172static long n_rcu_torture_barrier_error;
173static long n_rcu_torture_boost_ktrerror;
174static long n_rcu_torture_boost_rterror;
175static long n_rcu_torture_boost_failure;
176static long n_rcu_torture_boosts;
177static long n_rcu_torture_timers;
178static long n_offline_attempts;
179static long n_offline_successes;
180static long n_online_attempts;
181static long n_online_successes;
182static long n_barrier_attempts;
183static long n_barrier_successes;
184static struct list_head rcu_torture_removed;
185static cpumask_var_t shuffle_tmp_mask;
186
187static int stutter_pause_test;
188
189#if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
190#define RCUTORTURE_RUNNABLE_INIT 1
191#else
192#define RCUTORTURE_RUNNABLE_INIT 0
193#endif
194int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT;
195module_param(rcutorture_runnable, int, 0444);
196MODULE_PARM_DESC(rcutorture_runnable, "Start rcutorture at boot");
197
198#if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
199#define rcu_can_boost() 1
200#else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
201#define rcu_can_boost() 0
202#endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
203
204static unsigned long shutdown_time; /* jiffies to system shutdown. */
205static unsigned long boost_starttime; /* jiffies of next boost test start. */
206DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
207 /* and boost task create/destroy. */
208static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
209static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
210static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
211static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
212
213/* Mediate rmmod and system shutdown. Concurrent rmmod & shutdown illegal! */
214
215#define FULLSTOP_DONTSTOP 0 /* Normal operation. */
216#define FULLSTOP_SHUTDOWN 1 /* System shutdown with rcutorture running. */
217#define FULLSTOP_RMMOD 2 /* Normal rmmod of rcutorture. */
218static int fullstop = FULLSTOP_RMMOD;
219/*
220 * Protect fullstop transitions and spawning of kthreads.
221 */
222static DEFINE_MUTEX(fullstop_mutex);
223
224/* Forward reference. */
225static void rcu_torture_cleanup(void);
226
227/*
228 * Detect and respond to a system shutdown.
229 */
230static int
231rcutorture_shutdown_notify(struct notifier_block *unused1,
232 unsigned long unused2, void *unused3)
233{
234 mutex_lock(&fullstop_mutex);
235 if (fullstop == FULLSTOP_DONTSTOP)
236 fullstop = FULLSTOP_SHUTDOWN;
237 else
238 printk(KERN_WARNING /* but going down anyway, so... */
239 "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
240 mutex_unlock(&fullstop_mutex);
241 return NOTIFY_DONE;
242}
243
244/*
245 * Absorb kthreads into a kernel function that won't return, so that
246 * they won't ever access module text or data again.
247 */
248static void rcutorture_shutdown_absorb(char *title)
249{
250 if (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
251 printk(KERN_NOTICE
252 "rcutorture thread %s parking due to system shutdown\n",
253 title);
254 schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
255 }
256}
257
258/*
259 * Allocate an element from the rcu_tortures pool.
260 */
261static struct rcu_torture *
262rcu_torture_alloc(void)
263{
264 struct list_head *p;
265
266 spin_lock_bh(&rcu_torture_lock);
267 if (list_empty(&rcu_torture_freelist)) {
268 atomic_inc(&n_rcu_torture_alloc_fail);
269 spin_unlock_bh(&rcu_torture_lock);
270 return NULL;
271 }
272 atomic_inc(&n_rcu_torture_alloc);
273 p = rcu_torture_freelist.next;
274 list_del_init(p);
275 spin_unlock_bh(&rcu_torture_lock);
276 return container_of(p, struct rcu_torture, rtort_free);
277}
278
279/*
280 * Free an element to the rcu_tortures pool.
281 */
282static void
283rcu_torture_free(struct rcu_torture *p)
284{
285 atomic_inc(&n_rcu_torture_free);
286 spin_lock_bh(&rcu_torture_lock);
287 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
288 spin_unlock_bh(&rcu_torture_lock);
289}
290
291struct rcu_random_state {
292 unsigned long rrs_state;
293 long rrs_count;
294};
295
296#define RCU_RANDOM_MULT 39916801 /* prime */
297#define RCU_RANDOM_ADD 479001701 /* prime */
298#define RCU_RANDOM_REFRESH 10000
299
300#define DEFINE_RCU_RANDOM(name) struct rcu_random_state name = { 0, 0 }
301
302/*
303 * Crude but fast random-number generator. Uses a linear congruential
304 * generator, with occasional help from cpu_clock().
305 */
306static unsigned long
307rcu_random(struct rcu_random_state *rrsp)
308{
309 if (--rrsp->rrs_count < 0) {
310 rrsp->rrs_state += (unsigned long)local_clock();
311 rrsp->rrs_count = RCU_RANDOM_REFRESH;
312 }
313 rrsp->rrs_state = rrsp->rrs_state * RCU_RANDOM_MULT + RCU_RANDOM_ADD;
314 return swahw32(rrsp->rrs_state);
315}
316
317static void
318rcu_stutter_wait(char *title)
319{
320 while (stutter_pause_test || !rcutorture_runnable) {
321 if (rcutorture_runnable)
322 schedule_timeout_interruptible(1);
323 else
324 schedule_timeout_interruptible(round_jiffies_relative(HZ));
325 rcutorture_shutdown_absorb(title);
326 }
327}
328
329/*
330 * Operations vector for selecting different types of tests.
331 */
332
333struct rcu_torture_ops {
334 void (*init)(void);
335 void (*cleanup)(void);
336 int (*readlock)(void);
337 void (*read_delay)(struct rcu_random_state *rrsp);
338 void (*readunlock)(int idx);
339 int (*completed)(void);
340 void (*deferred_free)(struct rcu_torture *p);
341 void (*sync)(void);
342 void (*call)(struct rcu_head *head, void (*func)(struct rcu_head *rcu));
343 void (*cb_barrier)(void);
344 void (*fqs)(void);
345 int (*stats)(char *page);
346 int irq_capable;
347 int can_boost;
348 char *name;
349};
350
351static struct rcu_torture_ops *cur_ops;
352
353/*
354 * Definitions for rcu torture testing.
355 */
356
357static int rcu_torture_read_lock(void) __acquires(RCU)
358{
359 rcu_read_lock();
360 return 0;
361}
362
363static void rcu_read_delay(struct rcu_random_state *rrsp)
364{
365 const unsigned long shortdelay_us = 200;
366 const unsigned long longdelay_ms = 50;
367
368 /* We want a short delay sometimes to make a reader delay the grace
369 * period, and we want a long delay occasionally to trigger
370 * force_quiescent_state. */
371
372 if (!(rcu_random(rrsp) % (nrealreaders * 2000 * longdelay_ms)))
373 mdelay(longdelay_ms);
374 if (!(rcu_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
375 udelay(shortdelay_us);
376#ifdef CONFIG_PREEMPT
377 if (!preempt_count() && !(rcu_random(rrsp) % (nrealreaders * 20000)))
378 preempt_schedule(); /* No QS if preempt_disable() in effect */
379#endif
380}
381
382static void rcu_torture_read_unlock(int idx) __releases(RCU)
383{
384 rcu_read_unlock();
385}
386
387static int rcu_torture_completed(void)
388{
389 return rcu_batches_completed();
390}
391
392static void
393rcu_torture_cb(struct rcu_head *p)
394{
395 int i;
396 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
397
398 if (fullstop != FULLSTOP_DONTSTOP) {
399 /* Test is ending, just drop callbacks on the floor. */
400 /* The next initialization will pick up the pieces. */
401 return;
402 }
403 i = rp->rtort_pipe_count;
404 if (i > RCU_TORTURE_PIPE_LEN)
405 i = RCU_TORTURE_PIPE_LEN;
406 atomic_inc(&rcu_torture_wcount[i]);
407 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
408 rp->rtort_mbtest = 0;
409 rcu_torture_free(rp);
410 } else
411 cur_ops->deferred_free(rp);
412}
413
414static int rcu_no_completed(void)
415{
416 return 0;
417}
418
419static void rcu_torture_deferred_free(struct rcu_torture *p)
420{
421 call_rcu(&p->rtort_rcu, rcu_torture_cb);
422}
423
424static struct rcu_torture_ops rcu_ops = {
425 .init = NULL,
426 .cleanup = NULL,
427 .readlock = rcu_torture_read_lock,
428 .read_delay = rcu_read_delay,
429 .readunlock = rcu_torture_read_unlock,
430 .completed = rcu_torture_completed,
431 .deferred_free = rcu_torture_deferred_free,
432 .sync = synchronize_rcu,
433 .call = call_rcu,
434 .cb_barrier = rcu_barrier,
435 .fqs = rcu_force_quiescent_state,
436 .stats = NULL,
437 .irq_capable = 1,
438 .can_boost = rcu_can_boost(),
439 .name = "rcu"
440};
441
442static void rcu_sync_torture_deferred_free(struct rcu_torture *p)
443{
444 int i;
445 struct rcu_torture *rp;
446 struct rcu_torture *rp1;
447
448 cur_ops->sync();
449 list_add(&p->rtort_free, &rcu_torture_removed);
450 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
451 i = rp->rtort_pipe_count;
452 if (i > RCU_TORTURE_PIPE_LEN)
453 i = RCU_TORTURE_PIPE_LEN;
454 atomic_inc(&rcu_torture_wcount[i]);
455 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
456 rp->rtort_mbtest = 0;
457 list_del(&rp->rtort_free);
458 rcu_torture_free(rp);
459 }
460 }
461}
462
463static void rcu_sync_torture_init(void)
464{
465 INIT_LIST_HEAD(&rcu_torture_removed);
466}
467
468static struct rcu_torture_ops rcu_sync_ops = {
469 .init = rcu_sync_torture_init,
470 .cleanup = NULL,
471 .readlock = rcu_torture_read_lock,
472 .read_delay = rcu_read_delay,
473 .readunlock = rcu_torture_read_unlock,
474 .completed = rcu_torture_completed,
475 .deferred_free = rcu_sync_torture_deferred_free,
476 .sync = synchronize_rcu,
477 .call = NULL,
478 .cb_barrier = NULL,
479 .fqs = rcu_force_quiescent_state,
480 .stats = NULL,
481 .irq_capable = 1,
482 .can_boost = rcu_can_boost(),
483 .name = "rcu_sync"
484};
485
486static struct rcu_torture_ops rcu_expedited_ops = {
487 .init = rcu_sync_torture_init,
488 .cleanup = NULL,
489 .readlock = rcu_torture_read_lock,
490 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
491 .readunlock = rcu_torture_read_unlock,
492 .completed = rcu_no_completed,
493 .deferred_free = rcu_sync_torture_deferred_free,
494 .sync = synchronize_rcu_expedited,
495 .call = NULL,
496 .cb_barrier = NULL,
497 .fqs = rcu_force_quiescent_state,
498 .stats = NULL,
499 .irq_capable = 1,
500 .can_boost = rcu_can_boost(),
501 .name = "rcu_expedited"
502};
503
504/*
505 * Definitions for rcu_bh torture testing.
506 */
507
508static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
509{
510 rcu_read_lock_bh();
511 return 0;
512}
513
514static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
515{
516 rcu_read_unlock_bh();
517}
518
519static int rcu_bh_torture_completed(void)
520{
521 return rcu_batches_completed_bh();
522}
523
524static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
525{
526 call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
527}
528
529static struct rcu_torture_ops rcu_bh_ops = {
530 .init = NULL,
531 .cleanup = NULL,
532 .readlock = rcu_bh_torture_read_lock,
533 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
534 .readunlock = rcu_bh_torture_read_unlock,
535 .completed = rcu_bh_torture_completed,
536 .deferred_free = rcu_bh_torture_deferred_free,
537 .sync = synchronize_rcu_bh,
538 .call = call_rcu_bh,
539 .cb_barrier = rcu_barrier_bh,
540 .fqs = rcu_bh_force_quiescent_state,
541 .stats = NULL,
542 .irq_capable = 1,
543 .name = "rcu_bh"
544};
545
546static struct rcu_torture_ops rcu_bh_sync_ops = {
547 .init = rcu_sync_torture_init,
548 .cleanup = NULL,
549 .readlock = rcu_bh_torture_read_lock,
550 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
551 .readunlock = rcu_bh_torture_read_unlock,
552 .completed = rcu_bh_torture_completed,
553 .deferred_free = rcu_sync_torture_deferred_free,
554 .sync = synchronize_rcu_bh,
555 .call = NULL,
556 .cb_barrier = NULL,
557 .fqs = rcu_bh_force_quiescent_state,
558 .stats = NULL,
559 .irq_capable = 1,
560 .name = "rcu_bh_sync"
561};
562
563static struct rcu_torture_ops rcu_bh_expedited_ops = {
564 .init = rcu_sync_torture_init,
565 .cleanup = NULL,
566 .readlock = rcu_bh_torture_read_lock,
567 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
568 .readunlock = rcu_bh_torture_read_unlock,
569 .completed = rcu_bh_torture_completed,
570 .deferred_free = rcu_sync_torture_deferred_free,
571 .sync = synchronize_rcu_bh_expedited,
572 .call = NULL,
573 .cb_barrier = NULL,
574 .fqs = rcu_bh_force_quiescent_state,
575 .stats = NULL,
576 .irq_capable = 1,
577 .name = "rcu_bh_expedited"
578};
579
580/*
581 * Definitions for srcu torture testing.
582 */
583
584static struct srcu_struct srcu_ctl;
585
586static void srcu_torture_init(void)
587{
588 init_srcu_struct(&srcu_ctl);
589 rcu_sync_torture_init();
590}
591
592static void srcu_torture_cleanup(void)
593{
594 synchronize_srcu(&srcu_ctl);
595 cleanup_srcu_struct(&srcu_ctl);
596}
597
598static int srcu_torture_read_lock(void) __acquires(&srcu_ctl)
599{
600 return srcu_read_lock(&srcu_ctl);
601}
602
603static void srcu_read_delay(struct rcu_random_state *rrsp)
604{
605 long delay;
606 const long uspertick = 1000000 / HZ;
607 const long longdelay = 10;
608
609 /* We want there to be long-running readers, but not all the time. */
610
611 delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay * uspertick);
612 if (!delay)
613 schedule_timeout_interruptible(longdelay);
614 else
615 rcu_read_delay(rrsp);
616}
617
618static void srcu_torture_read_unlock(int idx) __releases(&srcu_ctl)
619{
620 srcu_read_unlock(&srcu_ctl, idx);
621}
622
623static int srcu_torture_completed(void)
624{
625 return srcu_batches_completed(&srcu_ctl);
626}
627
628static void srcu_torture_deferred_free(struct rcu_torture *rp)
629{
630 call_srcu(&srcu_ctl, &rp->rtort_rcu, rcu_torture_cb);
631}
632
633static void srcu_torture_synchronize(void)
634{
635 synchronize_srcu(&srcu_ctl);
636}
637
638static int srcu_torture_stats(char *page)
639{
640 int cnt = 0;
641 int cpu;
642 int idx = srcu_ctl.completed & 0x1;
643
644 cnt += sprintf(&page[cnt], "%s%s per-CPU(idx=%d):",
645 torture_type, TORTURE_FLAG, idx);
646 for_each_possible_cpu(cpu) {
647 cnt += sprintf(&page[cnt], " %d(%lu,%lu)", cpu,
648 per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx],
649 per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx]);
650 }
651 cnt += sprintf(&page[cnt], "\n");
652 return cnt;
653}
654
655static struct rcu_torture_ops srcu_ops = {
656 .init = srcu_torture_init,
657 .cleanup = srcu_torture_cleanup,
658 .readlock = srcu_torture_read_lock,
659 .read_delay = srcu_read_delay,
660 .readunlock = srcu_torture_read_unlock,
661 .completed = srcu_torture_completed,
662 .deferred_free = srcu_torture_deferred_free,
663 .sync = srcu_torture_synchronize,
664 .call = NULL,
665 .cb_barrier = NULL,
666 .stats = srcu_torture_stats,
667 .name = "srcu"
668};
669
670static struct rcu_torture_ops srcu_sync_ops = {
671 .init = srcu_torture_init,
672 .cleanup = srcu_torture_cleanup,
673 .readlock = srcu_torture_read_lock,
674 .read_delay = srcu_read_delay,
675 .readunlock = srcu_torture_read_unlock,
676 .completed = srcu_torture_completed,
677 .deferred_free = rcu_sync_torture_deferred_free,
678 .sync = srcu_torture_synchronize,
679 .call = NULL,
680 .cb_barrier = NULL,
681 .stats = srcu_torture_stats,
682 .name = "srcu_sync"
683};
684
685static int srcu_torture_read_lock_raw(void) __acquires(&srcu_ctl)
686{
687 return srcu_read_lock_raw(&srcu_ctl);
688}
689
690static void srcu_torture_read_unlock_raw(int idx) __releases(&srcu_ctl)
691{
692 srcu_read_unlock_raw(&srcu_ctl, idx);
693}
694
695static struct rcu_torture_ops srcu_raw_ops = {
696 .init = srcu_torture_init,
697 .cleanup = srcu_torture_cleanup,
698 .readlock = srcu_torture_read_lock_raw,
699 .read_delay = srcu_read_delay,
700 .readunlock = srcu_torture_read_unlock_raw,
701 .completed = srcu_torture_completed,
702 .deferred_free = srcu_torture_deferred_free,
703 .sync = srcu_torture_synchronize,
704 .call = NULL,
705 .cb_barrier = NULL,
706 .stats = srcu_torture_stats,
707 .name = "srcu_raw"
708};
709
710static struct rcu_torture_ops srcu_raw_sync_ops = {
711 .init = srcu_torture_init,
712 .cleanup = srcu_torture_cleanup,
713 .readlock = srcu_torture_read_lock_raw,
714 .read_delay = srcu_read_delay,
715 .readunlock = srcu_torture_read_unlock_raw,
716 .completed = srcu_torture_completed,
717 .deferred_free = rcu_sync_torture_deferred_free,
718 .sync = srcu_torture_synchronize,
719 .call = NULL,
720 .cb_barrier = NULL,
721 .stats = srcu_torture_stats,
722 .name = "srcu_raw_sync"
723};
724
725static void srcu_torture_synchronize_expedited(void)
726{
727 synchronize_srcu_expedited(&srcu_ctl);
728}
729
730static struct rcu_torture_ops srcu_expedited_ops = {
731 .init = srcu_torture_init,
732 .cleanup = srcu_torture_cleanup,
733 .readlock = srcu_torture_read_lock,
734 .read_delay = srcu_read_delay,
735 .readunlock = srcu_torture_read_unlock,
736 .completed = srcu_torture_completed,
737 .deferred_free = rcu_sync_torture_deferred_free,
738 .sync = srcu_torture_synchronize_expedited,
739 .call = NULL,
740 .cb_barrier = NULL,
741 .stats = srcu_torture_stats,
742 .name = "srcu_expedited"
743};
744
745/*
746 * Definitions for sched torture testing.
747 */
748
749static int sched_torture_read_lock(void)
750{
751 preempt_disable();
752 return 0;
753}
754
755static void sched_torture_read_unlock(int idx)
756{
757 preempt_enable();
758}
759
760static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
761{
762 call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
763}
764
765static struct rcu_torture_ops sched_ops = {
766 .init = rcu_sync_torture_init,
767 .cleanup = NULL,
768 .readlock = sched_torture_read_lock,
769 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
770 .readunlock = sched_torture_read_unlock,
771 .completed = rcu_no_completed,
772 .deferred_free = rcu_sched_torture_deferred_free,
773 .sync = synchronize_sched,
774 .cb_barrier = rcu_barrier_sched,
775 .fqs = rcu_sched_force_quiescent_state,
776 .stats = NULL,
777 .irq_capable = 1,
778 .name = "sched"
779};
780
781static struct rcu_torture_ops sched_sync_ops = {
782 .init = rcu_sync_torture_init,
783 .cleanup = NULL,
784 .readlock = sched_torture_read_lock,
785 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
786 .readunlock = sched_torture_read_unlock,
787 .completed = rcu_no_completed,
788 .deferred_free = rcu_sync_torture_deferred_free,
789 .sync = synchronize_sched,
790 .cb_barrier = NULL,
791 .fqs = rcu_sched_force_quiescent_state,
792 .stats = NULL,
793 .name = "sched_sync"
794};
795
796static struct rcu_torture_ops sched_expedited_ops = {
797 .init = rcu_sync_torture_init,
798 .cleanup = NULL,
799 .readlock = sched_torture_read_lock,
800 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
801 .readunlock = sched_torture_read_unlock,
802 .completed = rcu_no_completed,
803 .deferred_free = rcu_sync_torture_deferred_free,
804 .sync = synchronize_sched_expedited,
805 .cb_barrier = NULL,
806 .fqs = rcu_sched_force_quiescent_state,
807 .stats = NULL,
808 .irq_capable = 1,
809 .name = "sched_expedited"
810};
811
812/*
813 * RCU torture priority-boost testing. Runs one real-time thread per
814 * CPU for moderate bursts, repeatedly registering RCU callbacks and
815 * spinning waiting for them to be invoked. If a given callback takes
816 * too long to be invoked, we assume that priority inversion has occurred.
817 */
818
819struct rcu_boost_inflight {
820 struct rcu_head rcu;
821 int inflight;
822};
823
824static void rcu_torture_boost_cb(struct rcu_head *head)
825{
826 struct rcu_boost_inflight *rbip =
827 container_of(head, struct rcu_boost_inflight, rcu);
828
829 smp_mb(); /* Ensure RCU-core accesses precede clearing ->inflight */
830 rbip->inflight = 0;
831}
832
833static int rcu_torture_boost(void *arg)
834{
835 unsigned long call_rcu_time;
836 unsigned long endtime;
837 unsigned long oldstarttime;
838 struct rcu_boost_inflight rbi = { .inflight = 0 };
839 struct sched_param sp;
840
841 VERBOSE_PRINTK_STRING("rcu_torture_boost started");
842
843 /* Set real-time priority. */
844 sp.sched_priority = 1;
845 if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
846 VERBOSE_PRINTK_STRING("rcu_torture_boost RT prio failed!");
847 n_rcu_torture_boost_rterror++;
848 }
849
850 init_rcu_head_on_stack(&rbi.rcu);
851 /* Each pass through the following loop does one boost-test cycle. */
852 do {
853 /* Wait for the next test interval. */
854 oldstarttime = boost_starttime;
855 while (ULONG_CMP_LT(jiffies, oldstarttime)) {
856 schedule_timeout_uninterruptible(1);
857 rcu_stutter_wait("rcu_torture_boost");
858 if (kthread_should_stop() ||
859 fullstop != FULLSTOP_DONTSTOP)
860 goto checkwait;
861 }
862
863 /* Do one boost-test interval. */
864 endtime = oldstarttime + test_boost_duration * HZ;
865 call_rcu_time = jiffies;
866 while (ULONG_CMP_LT(jiffies, endtime)) {
867 /* If we don't have a callback in flight, post one. */
868 if (!rbi.inflight) {
869 smp_mb(); /* RCU core before ->inflight = 1. */
870 rbi.inflight = 1;
871 call_rcu(&rbi.rcu, rcu_torture_boost_cb);
872 if (jiffies - call_rcu_time >
873 test_boost_duration * HZ - HZ / 2) {
874 VERBOSE_PRINTK_STRING("rcu_torture_boost boosting failed");
875 n_rcu_torture_boost_failure++;
876 }
877 call_rcu_time = jiffies;
878 }
879 cond_resched();
880 rcu_stutter_wait("rcu_torture_boost");
881 if (kthread_should_stop() ||
882 fullstop != FULLSTOP_DONTSTOP)
883 goto checkwait;
884 }
885
886 /*
887 * Set the start time of the next test interval.
888 * Yes, this is vulnerable to long delays, but such
889 * delays simply cause a false negative for the next
890 * interval. Besides, we are running at RT priority,
891 * so delays should be relatively rare.
892 */
893 while (oldstarttime == boost_starttime &&
894 !kthread_should_stop()) {
895 if (mutex_trylock(&boost_mutex)) {
896 boost_starttime = jiffies +
897 test_boost_interval * HZ;
898 n_rcu_torture_boosts++;
899 mutex_unlock(&boost_mutex);
900 break;
901 }
902 schedule_timeout_uninterruptible(1);
903 }
904
905 /* Go do the stutter. */
906checkwait: rcu_stutter_wait("rcu_torture_boost");
907 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
908
909 /* Clean up and exit. */
910 VERBOSE_PRINTK_STRING("rcu_torture_boost task stopping");
911 rcutorture_shutdown_absorb("rcu_torture_boost");
912 while (!kthread_should_stop() || rbi.inflight)
913 schedule_timeout_uninterruptible(1);
914 smp_mb(); /* order accesses to ->inflight before stack-frame death. */
915 destroy_rcu_head_on_stack(&rbi.rcu);
916 return 0;
917}
918
919/*
920 * RCU torture force-quiescent-state kthread. Repeatedly induces
921 * bursts of calls to force_quiescent_state(), increasing the probability
922 * of occurrence of some important types of race conditions.
923 */
924static int
925rcu_torture_fqs(void *arg)
926{
927 unsigned long fqs_resume_time;
928 int fqs_burst_remaining;
929
930 VERBOSE_PRINTK_STRING("rcu_torture_fqs task started");
931 do {
932 fqs_resume_time = jiffies + fqs_stutter * HZ;
933 while (ULONG_CMP_LT(jiffies, fqs_resume_time) &&
934 !kthread_should_stop()) {
935 schedule_timeout_interruptible(1);
936 }
937 fqs_burst_remaining = fqs_duration;
938 while (fqs_burst_remaining > 0 &&
939 !kthread_should_stop()) {
940 cur_ops->fqs();
941 udelay(fqs_holdoff);
942 fqs_burst_remaining -= fqs_holdoff;
943 }
944 rcu_stutter_wait("rcu_torture_fqs");
945 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
946 VERBOSE_PRINTK_STRING("rcu_torture_fqs task stopping");
947 rcutorture_shutdown_absorb("rcu_torture_fqs");
948 while (!kthread_should_stop())
949 schedule_timeout_uninterruptible(1);
950 return 0;
951}
952
953/*
954 * RCU torture writer kthread. Repeatedly substitutes a new structure
955 * for that pointed to by rcu_torture_current, freeing the old structure
956 * after a series of grace periods (the "pipeline").
957 */
958static int
959rcu_torture_writer(void *arg)
960{
961 int i;
962 long oldbatch = rcu_batches_completed();
963 struct rcu_torture *rp;
964 struct rcu_torture *old_rp;
965 static DEFINE_RCU_RANDOM(rand);
966
967 VERBOSE_PRINTK_STRING("rcu_torture_writer task started");
968 set_user_nice(current, 19);
969
970 do {
971 schedule_timeout_uninterruptible(1);
972 rp = rcu_torture_alloc();
973 if (rp == NULL)
974 continue;
975 rp->rtort_pipe_count = 0;
976 udelay(rcu_random(&rand) & 0x3ff);
977 old_rp = rcu_dereference_check(rcu_torture_current,
978 current == writer_task);
979 rp->rtort_mbtest = 1;
980 rcu_assign_pointer(rcu_torture_current, rp);
981 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
982 if (old_rp) {
983 i = old_rp->rtort_pipe_count;
984 if (i > RCU_TORTURE_PIPE_LEN)
985 i = RCU_TORTURE_PIPE_LEN;
986 atomic_inc(&rcu_torture_wcount[i]);
987 old_rp->rtort_pipe_count++;
988 cur_ops->deferred_free(old_rp);
989 }
990 rcutorture_record_progress(++rcu_torture_current_version);
991 oldbatch = cur_ops->completed();
992 rcu_stutter_wait("rcu_torture_writer");
993 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
994 VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
995 rcutorture_shutdown_absorb("rcu_torture_writer");
996 while (!kthread_should_stop())
997 schedule_timeout_uninterruptible(1);
998 return 0;
999}
1000
1001/*
1002 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
1003 * delay between calls.
1004 */
1005static int
1006rcu_torture_fakewriter(void *arg)
1007{
1008 DEFINE_RCU_RANDOM(rand);
1009
1010 VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started");
1011 set_user_nice(current, 19);
1012
1013 do {
1014 schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10);
1015 udelay(rcu_random(&rand) & 0x3ff);
1016 cur_ops->sync();
1017 rcu_stutter_wait("rcu_torture_fakewriter");
1018 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
1019
1020 VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
1021 rcutorture_shutdown_absorb("rcu_torture_fakewriter");
1022 while (!kthread_should_stop())
1023 schedule_timeout_uninterruptible(1);
1024 return 0;
1025}
1026
1027void rcutorture_trace_dump(void)
1028{
1029 static atomic_t beenhere = ATOMIC_INIT(0);
1030
1031 if (atomic_read(&beenhere))
1032 return;
1033 if (atomic_xchg(&beenhere, 1) != 0)
1034 return;
1035 do_trace_rcu_torture_read(cur_ops->name, (struct rcu_head *)~0UL);
1036 ftrace_dump(DUMP_ALL);
1037}
1038
1039/*
1040 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
1041 * incrementing the corresponding element of the pipeline array. The
1042 * counter in the element should never be greater than 1, otherwise, the
1043 * RCU implementation is broken.
1044 */
1045static void rcu_torture_timer(unsigned long unused)
1046{
1047 int idx;
1048 int completed;
1049 static DEFINE_RCU_RANDOM(rand);
1050 static DEFINE_SPINLOCK(rand_lock);
1051 struct rcu_torture *p;
1052 int pipe_count;
1053
1054 idx = cur_ops->readlock();
1055 completed = cur_ops->completed();
1056 p = rcu_dereference_check(rcu_torture_current,
1057 rcu_read_lock_bh_held() ||
1058 rcu_read_lock_sched_held() ||
1059 srcu_read_lock_held(&srcu_ctl));
1060 if (p == NULL) {
1061 /* Leave because rcu_torture_writer is not yet underway */
1062 cur_ops->readunlock(idx);
1063 return;
1064 }
1065 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu);
1066 if (p->rtort_mbtest == 0)
1067 atomic_inc(&n_rcu_torture_mberror);
1068 spin_lock(&rand_lock);
1069 cur_ops->read_delay(&rand);
1070 n_rcu_torture_timers++;
1071 spin_unlock(&rand_lock);
1072 preempt_disable();
1073 pipe_count = p->rtort_pipe_count;
1074 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1075 /* Should not happen, but... */
1076 pipe_count = RCU_TORTURE_PIPE_LEN;
1077 }
1078 if (pipe_count > 1)
1079 rcutorture_trace_dump();
1080 __this_cpu_inc(rcu_torture_count[pipe_count]);
1081 completed = cur_ops->completed() - completed;
1082 if (completed > RCU_TORTURE_PIPE_LEN) {
1083 /* Should not happen, but... */
1084 completed = RCU_TORTURE_PIPE_LEN;
1085 }
1086 __this_cpu_inc(rcu_torture_batch[completed]);
1087 preempt_enable();
1088 cur_ops->readunlock(idx);
1089}
1090
1091/*
1092 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
1093 * incrementing the corresponding element of the pipeline array. The
1094 * counter in the element should never be greater than 1, otherwise, the
1095 * RCU implementation is broken.
1096 */
1097static int
1098rcu_torture_reader(void *arg)
1099{
1100 int completed;
1101 int idx;
1102 DEFINE_RCU_RANDOM(rand);
1103 struct rcu_torture *p;
1104 int pipe_count;
1105 struct timer_list t;
1106
1107 VERBOSE_PRINTK_STRING("rcu_torture_reader task started");
1108 set_user_nice(current, 19);
1109 if (irqreader && cur_ops->irq_capable)
1110 setup_timer_on_stack(&t, rcu_torture_timer, 0);
1111
1112 do {
1113 if (irqreader && cur_ops->irq_capable) {
1114 if (!timer_pending(&t))
1115 mod_timer(&t, jiffies + 1);
1116 }
1117 idx = cur_ops->readlock();
1118 completed = cur_ops->completed();
1119 p = rcu_dereference_check(rcu_torture_current,
1120 rcu_read_lock_bh_held() ||
1121 rcu_read_lock_sched_held() ||
1122 srcu_read_lock_held(&srcu_ctl));
1123 if (p == NULL) {
1124 /* Wait for rcu_torture_writer to get underway */
1125 cur_ops->readunlock(idx);
1126 schedule_timeout_interruptible(HZ);
1127 continue;
1128 }
1129 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu);
1130 if (p->rtort_mbtest == 0)
1131 atomic_inc(&n_rcu_torture_mberror);
1132 cur_ops->read_delay(&rand);
1133 preempt_disable();
1134 pipe_count = p->rtort_pipe_count;
1135 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1136 /* Should not happen, but... */
1137 pipe_count = RCU_TORTURE_PIPE_LEN;
1138 }
1139 if (pipe_count > 1)
1140 rcutorture_trace_dump();
1141 __this_cpu_inc(rcu_torture_count[pipe_count]);
1142 completed = cur_ops->completed() - completed;
1143 if (completed > RCU_TORTURE_PIPE_LEN) {
1144 /* Should not happen, but... */
1145 completed = RCU_TORTURE_PIPE_LEN;
1146 }
1147 __this_cpu_inc(rcu_torture_batch[completed]);
1148 preempt_enable();
1149 cur_ops->readunlock(idx);
1150 schedule();
1151 rcu_stutter_wait("rcu_torture_reader");
1152 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
1153 VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
1154 rcutorture_shutdown_absorb("rcu_torture_reader");
1155 if (irqreader && cur_ops->irq_capable)
1156 del_timer_sync(&t);
1157 while (!kthread_should_stop())
1158 schedule_timeout_uninterruptible(1);
1159 return 0;
1160}
1161
1162/*
1163 * Create an RCU-torture statistics message in the specified buffer.
1164 */
1165static int
1166rcu_torture_printk(char *page)
1167{
1168 int cnt = 0;
1169 int cpu;
1170 int i;
1171 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1172 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1173
1174 for_each_possible_cpu(cpu) {
1175 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1176 pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
1177 batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
1178 }
1179 }
1180 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
1181 if (pipesummary[i] != 0)
1182 break;
1183 }
1184 cnt += sprintf(&page[cnt], "%s%s ", torture_type, TORTURE_FLAG);
1185 cnt += sprintf(&page[cnt],
1186 "rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d "
1187 "rtmbe: %d rtbke: %ld rtbre: %ld "
1188 "rtbf: %ld rtb: %ld nt: %ld "
1189 "onoff: %ld/%ld:%ld/%ld "
1190 "barrier: %ld/%ld:%ld",
1191 rcu_torture_current,
1192 rcu_torture_current_version,
1193 list_empty(&rcu_torture_freelist),
1194 atomic_read(&n_rcu_torture_alloc),
1195 atomic_read(&n_rcu_torture_alloc_fail),
1196 atomic_read(&n_rcu_torture_free),
1197 atomic_read(&n_rcu_torture_mberror),
1198 n_rcu_torture_boost_ktrerror,
1199 n_rcu_torture_boost_rterror,
1200 n_rcu_torture_boost_failure,
1201 n_rcu_torture_boosts,
1202 n_rcu_torture_timers,
1203 n_online_successes,
1204 n_online_attempts,
1205 n_offline_successes,
1206 n_offline_attempts,
1207 n_barrier_successes,
1208 n_barrier_attempts,
1209 n_rcu_torture_barrier_error);
1210 cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
1211 if (atomic_read(&n_rcu_torture_mberror) != 0 ||
1212 n_rcu_torture_barrier_error != 0 ||
1213 n_rcu_torture_boost_ktrerror != 0 ||
1214 n_rcu_torture_boost_rterror != 0 ||
1215 n_rcu_torture_boost_failure != 0 ||
1216 i > 1) {
1217 cnt += sprintf(&page[cnt], "!!! ");
1218 atomic_inc(&n_rcu_torture_error);
1219 WARN_ON_ONCE(1);
1220 }
1221 cnt += sprintf(&page[cnt], "Reader Pipe: ");
1222 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1223 cnt += sprintf(&page[cnt], " %ld", pipesummary[i]);
1224 cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
1225 cnt += sprintf(&page[cnt], "Reader Batch: ");
1226 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1227 cnt += sprintf(&page[cnt], " %ld", batchsummary[i]);
1228 cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
1229 cnt += sprintf(&page[cnt], "Free-Block Circulation: ");
1230 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1231 cnt += sprintf(&page[cnt], " %d",
1232 atomic_read(&rcu_torture_wcount[i]));
1233 }
1234 cnt += sprintf(&page[cnt], "\n");
1235 if (cur_ops->stats)
1236 cnt += cur_ops->stats(&page[cnt]);
1237 return cnt;
1238}
1239
1240/*
1241 * Print torture statistics. Caller must ensure that there is only
1242 * one call to this function at a given time!!! This is normally
1243 * accomplished by relying on the module system to only have one copy
1244 * of the module loaded, and then by giving the rcu_torture_stats
1245 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1246 * thread is not running).
1247 */
1248static void
1249rcu_torture_stats_print(void)
1250{
1251 int cnt;
1252
1253 cnt = rcu_torture_printk(printk_buf);
1254 printk(KERN_ALERT "%s", printk_buf);
1255}
1256
1257/*
1258 * Periodically prints torture statistics, if periodic statistics printing
1259 * was specified via the stat_interval module parameter.
1260 *
1261 * No need to worry about fullstop here, since this one doesn't reference
1262 * volatile state or register callbacks.
1263 */
1264static int
1265rcu_torture_stats(void *arg)
1266{
1267 VERBOSE_PRINTK_STRING("rcu_torture_stats task started");
1268 do {
1269 schedule_timeout_interruptible(stat_interval * HZ);
1270 rcu_torture_stats_print();
1271 rcutorture_shutdown_absorb("rcu_torture_stats");
1272 } while (!kthread_should_stop());
1273 VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping");
1274 return 0;
1275}
1276
1277static int rcu_idle_cpu; /* Force all torture tasks off this CPU */
1278
1279/* Shuffle tasks such that we allow @rcu_idle_cpu to become idle. A special case
1280 * is when @rcu_idle_cpu = -1, when we allow the tasks to run on all CPUs.
1281 */
1282static void rcu_torture_shuffle_tasks(void)
1283{
1284 int i;
1285
1286 cpumask_setall(shuffle_tmp_mask);
1287 get_online_cpus();
1288
1289 /* No point in shuffling if there is only one online CPU (ex: UP) */
1290 if (num_online_cpus() == 1) {
1291 put_online_cpus();
1292 return;
1293 }
1294
1295 if (rcu_idle_cpu != -1)
1296 cpumask_clear_cpu(rcu_idle_cpu, shuffle_tmp_mask);
1297
1298 set_cpus_allowed_ptr(current, shuffle_tmp_mask);
1299
1300 if (reader_tasks) {
1301 for (i = 0; i < nrealreaders; i++)
1302 if (reader_tasks[i])
1303 set_cpus_allowed_ptr(reader_tasks[i],
1304 shuffle_tmp_mask);
1305 }
1306
1307 if (fakewriter_tasks) {
1308 for (i = 0; i < nfakewriters; i++)
1309 if (fakewriter_tasks[i])
1310 set_cpus_allowed_ptr(fakewriter_tasks[i],
1311 shuffle_tmp_mask);
1312 }
1313
1314 if (writer_task)
1315 set_cpus_allowed_ptr(writer_task, shuffle_tmp_mask);
1316
1317 if (stats_task)
1318 set_cpus_allowed_ptr(stats_task, shuffle_tmp_mask);
1319
1320 if (rcu_idle_cpu == -1)
1321 rcu_idle_cpu = num_online_cpus() - 1;
1322 else
1323 rcu_idle_cpu--;
1324
1325 put_online_cpus();
1326}
1327
1328/* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
1329 * system to become idle at a time and cut off its timer ticks. This is meant
1330 * to test the support for such tickless idle CPU in RCU.
1331 */
1332static int
1333rcu_torture_shuffle(void *arg)
1334{
1335 VERBOSE_PRINTK_STRING("rcu_torture_shuffle task started");
1336 do {
1337 schedule_timeout_interruptible(shuffle_interval * HZ);
1338 rcu_torture_shuffle_tasks();
1339 rcutorture_shutdown_absorb("rcu_torture_shuffle");
1340 } while (!kthread_should_stop());
1341 VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping");
1342 return 0;
1343}
1344
1345/* Cause the rcutorture test to "stutter", starting and stopping all
1346 * threads periodically.
1347 */
1348static int
1349rcu_torture_stutter(void *arg)
1350{
1351 VERBOSE_PRINTK_STRING("rcu_torture_stutter task started");
1352 do {
1353 schedule_timeout_interruptible(stutter * HZ);
1354 stutter_pause_test = 1;
1355 if (!kthread_should_stop())
1356 schedule_timeout_interruptible(stutter * HZ);
1357 stutter_pause_test = 0;
1358 rcutorture_shutdown_absorb("rcu_torture_stutter");
1359 } while (!kthread_should_stop());
1360 VERBOSE_PRINTK_STRING("rcu_torture_stutter task stopping");
1361 return 0;
1362}
1363
1364static inline void
1365rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, char *tag)
1366{
1367 printk(KERN_ALERT "%s" TORTURE_FLAG
1368 "--- %s: nreaders=%d nfakewriters=%d "
1369 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1370 "shuffle_interval=%d stutter=%d irqreader=%d "
1371 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1372 "test_boost=%d/%d test_boost_interval=%d "
1373 "test_boost_duration=%d shutdown_secs=%d "
1374 "onoff_interval=%d onoff_holdoff=%d\n",
1375 torture_type, tag, nrealreaders, nfakewriters,
1376 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1377 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1378 test_boost, cur_ops->can_boost,
1379 test_boost_interval, test_boost_duration, shutdown_secs,
1380 onoff_interval, onoff_holdoff);
1381}
1382
1383static struct notifier_block rcutorture_shutdown_nb = {
1384 .notifier_call = rcutorture_shutdown_notify,
1385};
1386
1387static void rcutorture_booster_cleanup(int cpu)
1388{
1389 struct task_struct *t;
1390
1391 if (boost_tasks[cpu] == NULL)
1392 return;
1393 mutex_lock(&boost_mutex);
1394 VERBOSE_PRINTK_STRING("Stopping rcu_torture_boost task");
1395 t = boost_tasks[cpu];
1396 boost_tasks[cpu] = NULL;
1397 mutex_unlock(&boost_mutex);
1398
1399 /* This must be outside of the mutex, otherwise deadlock! */
1400 kthread_stop(t);
1401 boost_tasks[cpu] = NULL;
1402}
1403
1404static int rcutorture_booster_init(int cpu)
1405{
1406 int retval;
1407
1408 if (boost_tasks[cpu] != NULL)
1409 return 0; /* Already created, nothing more to do. */
1410
1411 /* Don't allow time recalculation while creating a new task. */
1412 mutex_lock(&boost_mutex);
1413 VERBOSE_PRINTK_STRING("Creating rcu_torture_boost task");
1414 boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
1415 cpu_to_node(cpu),
1416 "rcu_torture_boost");
1417 if (IS_ERR(boost_tasks[cpu])) {
1418 retval = PTR_ERR(boost_tasks[cpu]);
1419 VERBOSE_PRINTK_STRING("rcu_torture_boost task create failed");
1420 n_rcu_torture_boost_ktrerror++;
1421 boost_tasks[cpu] = NULL;
1422 mutex_unlock(&boost_mutex);
1423 return retval;
1424 }
1425 kthread_bind(boost_tasks[cpu], cpu);
1426 wake_up_process(boost_tasks[cpu]);
1427 mutex_unlock(&boost_mutex);
1428 return 0;
1429}
1430
1431/*
1432 * Cause the rcutorture test to shutdown the system after the test has
1433 * run for the time specified by the shutdown_secs module parameter.
1434 */
1435static int
1436rcu_torture_shutdown(void *arg)
1437{
1438 long delta;
1439 unsigned long jiffies_snap;
1440
1441 VERBOSE_PRINTK_STRING("rcu_torture_shutdown task started");
1442 jiffies_snap = ACCESS_ONCE(jiffies);
1443 while (ULONG_CMP_LT(jiffies_snap, shutdown_time) &&
1444 !kthread_should_stop()) {
1445 delta = shutdown_time - jiffies_snap;
1446 if (verbose)
1447 printk(KERN_ALERT "%s" TORTURE_FLAG
1448 "rcu_torture_shutdown task: %lu "
1449 "jiffies remaining\n",
1450 torture_type, delta);
1451 schedule_timeout_interruptible(delta);
1452 jiffies_snap = ACCESS_ONCE(jiffies);
1453 }
1454 if (kthread_should_stop()) {
1455 VERBOSE_PRINTK_STRING("rcu_torture_shutdown task stopping");
1456 return 0;
1457 }
1458
1459 /* OK, shut down the system. */
1460
1461 VERBOSE_PRINTK_STRING("rcu_torture_shutdown task shutting down system");
1462 shutdown_task = NULL; /* Avoid self-kill deadlock. */
1463 rcu_torture_cleanup(); /* Get the success/failure message. */
1464 kernel_power_off(); /* Shut down the system. */
1465 return 0;
1466}
1467
1468#ifdef CONFIG_HOTPLUG_CPU
1469
1470/*
1471 * Execute random CPU-hotplug operations at the interval specified
1472 * by the onoff_interval.
1473 */
1474static int __cpuinit
1475rcu_torture_onoff(void *arg)
1476{
1477 int cpu;
1478 int maxcpu = -1;
1479 DEFINE_RCU_RANDOM(rand);
1480
1481 VERBOSE_PRINTK_STRING("rcu_torture_onoff task started");
1482 for_each_online_cpu(cpu)
1483 maxcpu = cpu;
1484 WARN_ON(maxcpu < 0);
1485 if (onoff_holdoff > 0) {
1486 VERBOSE_PRINTK_STRING("rcu_torture_onoff begin holdoff");
1487 schedule_timeout_interruptible(onoff_holdoff * HZ);
1488 VERBOSE_PRINTK_STRING("rcu_torture_onoff end holdoff");
1489 }
1490 while (!kthread_should_stop()) {
1491 cpu = (rcu_random(&rand) >> 4) % (maxcpu + 1);
1492 if (cpu_online(cpu) && cpu_is_hotpluggable(cpu)) {
1493 if (verbose)
1494 printk(KERN_ALERT "%s" TORTURE_FLAG
1495 "rcu_torture_onoff task: offlining %d\n",
1496 torture_type, cpu);
1497 n_offline_attempts++;
1498 if (cpu_down(cpu) == 0) {
1499 if (verbose)
1500 printk(KERN_ALERT "%s" TORTURE_FLAG
1501 "rcu_torture_onoff task: "
1502 "offlined %d\n",
1503 torture_type, cpu);
1504 n_offline_successes++;
1505 }
1506 } else if (cpu_is_hotpluggable(cpu)) {
1507 if (verbose)
1508 printk(KERN_ALERT "%s" TORTURE_FLAG
1509 "rcu_torture_onoff task: onlining %d\n",
1510 torture_type, cpu);
1511 n_online_attempts++;
1512 if (cpu_up(cpu) == 0) {
1513 if (verbose)
1514 printk(KERN_ALERT "%s" TORTURE_FLAG
1515 "rcu_torture_onoff task: "
1516 "onlined %d\n",
1517 torture_type, cpu);
1518 n_online_successes++;
1519 }
1520 }
1521 schedule_timeout_interruptible(onoff_interval * HZ);
1522 }
1523 VERBOSE_PRINTK_STRING("rcu_torture_onoff task stopping");
1524 return 0;
1525}
1526
1527static int __cpuinit
1528rcu_torture_onoff_init(void)
1529{
1530 int ret;
1531
1532 if (onoff_interval <= 0)
1533 return 0;
1534 onoff_task = kthread_run(rcu_torture_onoff, NULL, "rcu_torture_onoff");
1535 if (IS_ERR(onoff_task)) {
1536 ret = PTR_ERR(onoff_task);
1537 onoff_task = NULL;
1538 return ret;
1539 }
1540 return 0;
1541}
1542
1543static void rcu_torture_onoff_cleanup(void)
1544{
1545 if (onoff_task == NULL)
1546 return;
1547 VERBOSE_PRINTK_STRING("Stopping rcu_torture_onoff task");
1548 kthread_stop(onoff_task);
1549 onoff_task = NULL;
1550}
1551
1552#else /* #ifdef CONFIG_HOTPLUG_CPU */
1553
1554static int
1555rcu_torture_onoff_init(void)
1556{
1557 return 0;
1558}
1559
1560static void rcu_torture_onoff_cleanup(void)
1561{
1562}
1563
1564#endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
1565
1566/*
1567 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
1568 * induces a CPU stall for the time specified by stall_cpu.
1569 */
1570static int __cpuinit rcu_torture_stall(void *args)
1571{
1572 unsigned long stop_at;
1573
1574 VERBOSE_PRINTK_STRING("rcu_torture_stall task started");
1575 if (stall_cpu_holdoff > 0) {
1576 VERBOSE_PRINTK_STRING("rcu_torture_stall begin holdoff");
1577 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
1578 VERBOSE_PRINTK_STRING("rcu_torture_stall end holdoff");
1579 }
1580 if (!kthread_should_stop()) {
1581 stop_at = get_seconds() + stall_cpu;
1582 /* RCU CPU stall is expected behavior in following code. */
1583 printk(KERN_ALERT "rcu_torture_stall start.\n");
1584 rcu_read_lock();
1585 preempt_disable();
1586 while (ULONG_CMP_LT(get_seconds(), stop_at))
1587 continue; /* Induce RCU CPU stall warning. */
1588 preempt_enable();
1589 rcu_read_unlock();
1590 printk(KERN_ALERT "rcu_torture_stall end.\n");
1591 }
1592 rcutorture_shutdown_absorb("rcu_torture_stall");
1593 while (!kthread_should_stop())
1594 schedule_timeout_interruptible(10 * HZ);
1595 return 0;
1596}
1597
1598/* Spawn CPU-stall kthread, if stall_cpu specified. */
1599static int __init rcu_torture_stall_init(void)
1600{
1601 int ret;
1602
1603 if (stall_cpu <= 0)
1604 return 0;
1605 stall_task = kthread_run(rcu_torture_stall, NULL, "rcu_torture_stall");
1606 if (IS_ERR(stall_task)) {
1607 ret = PTR_ERR(stall_task);
1608 stall_task = NULL;
1609 return ret;
1610 }
1611 return 0;
1612}
1613
1614/* Clean up after the CPU-stall kthread, if one was spawned. */
1615static void rcu_torture_stall_cleanup(void)
1616{
1617 if (stall_task == NULL)
1618 return;
1619 VERBOSE_PRINTK_STRING("Stopping rcu_torture_stall_task.");
1620 kthread_stop(stall_task);
1621 stall_task = NULL;
1622}
1623
1624/* Callback function for RCU barrier testing. */
1625void rcu_torture_barrier_cbf(struct rcu_head *rcu)
1626{
1627 atomic_inc(&barrier_cbs_invoked);
1628}
1629
1630/* kthread function to register callbacks used to test RCU barriers. */
1631static int rcu_torture_barrier_cbs(void *arg)
1632{
1633 long myid = (long)arg;
1634 struct rcu_head rcu;
1635
1636 init_rcu_head_on_stack(&rcu);
1637 VERBOSE_PRINTK_STRING("rcu_torture_barrier_cbs task started");
1638 set_user_nice(current, 19);
1639 do {
1640 wait_event(barrier_cbs_wq[myid],
1641 atomic_read(&barrier_cbs_count) == n_barrier_cbs ||
1642 kthread_should_stop() ||
1643 fullstop != FULLSTOP_DONTSTOP);
1644 if (kthread_should_stop() || fullstop != FULLSTOP_DONTSTOP)
1645 break;
1646 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
1647 if (atomic_dec_and_test(&barrier_cbs_count))
1648 wake_up(&barrier_wq);
1649 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
1650 VERBOSE_PRINTK_STRING("rcu_torture_barrier_cbs task stopping");
1651 rcutorture_shutdown_absorb("rcu_torture_barrier_cbs");
1652 while (!kthread_should_stop())
1653 schedule_timeout_interruptible(1);
1654 cur_ops->cb_barrier();
1655 destroy_rcu_head_on_stack(&rcu);
1656 return 0;
1657}
1658
1659/* kthread function to drive and coordinate RCU barrier testing. */
1660static int rcu_torture_barrier(void *arg)
1661{
1662 int i;
1663
1664 VERBOSE_PRINTK_STRING("rcu_torture_barrier task starting");
1665 do {
1666 atomic_set(&barrier_cbs_invoked, 0);
1667 atomic_set(&barrier_cbs_count, n_barrier_cbs);
1668 /* wake_up() path contains the required barriers. */
1669 for (i = 0; i < n_barrier_cbs; i++)
1670 wake_up(&barrier_cbs_wq[i]);
1671 wait_event(barrier_wq,
1672 atomic_read(&barrier_cbs_count) == 0 ||
1673 kthread_should_stop() ||
1674 fullstop != FULLSTOP_DONTSTOP);
1675 if (kthread_should_stop() || fullstop != FULLSTOP_DONTSTOP)
1676 break;
1677 n_barrier_attempts++;
1678 cur_ops->cb_barrier();
1679 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
1680 n_rcu_torture_barrier_error++;
1681 WARN_ON_ONCE(1);
1682 }
1683 n_barrier_successes++;
1684 schedule_timeout_interruptible(HZ / 10);
1685 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
1686 VERBOSE_PRINTK_STRING("rcu_torture_barrier task stopping");
1687 rcutorture_shutdown_absorb("rcu_torture_barrier_cbs");
1688 while (!kthread_should_stop())
1689 schedule_timeout_interruptible(1);
1690 return 0;
1691}
1692
1693/* Initialize RCU barrier testing. */
1694static int rcu_torture_barrier_init(void)
1695{
1696 int i;
1697 int ret;
1698
1699 if (n_barrier_cbs == 0)
1700 return 0;
1701 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
1702 printk(KERN_ALERT "%s" TORTURE_FLAG
1703 " Call or barrier ops missing for %s,\n",
1704 torture_type, cur_ops->name);
1705 printk(KERN_ALERT "%s" TORTURE_FLAG
1706 " RCU barrier testing omitted from run.\n",
1707 torture_type);
1708 return 0;
1709 }
1710 atomic_set(&barrier_cbs_count, 0);
1711 atomic_set(&barrier_cbs_invoked, 0);
1712 barrier_cbs_tasks =
1713 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_tasks[0]),
1714 GFP_KERNEL);
1715 barrier_cbs_wq =
1716 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_wq[0]),
1717 GFP_KERNEL);
1718 if (barrier_cbs_tasks == NULL || barrier_cbs_wq == 0)
1719 return -ENOMEM;
1720 for (i = 0; i < n_barrier_cbs; i++) {
1721 init_waitqueue_head(&barrier_cbs_wq[i]);
1722 barrier_cbs_tasks[i] = kthread_run(rcu_torture_barrier_cbs,
1723 (void *)(long)i,
1724 "rcu_torture_barrier_cbs");
1725 if (IS_ERR(barrier_cbs_tasks[i])) {
1726 ret = PTR_ERR(barrier_cbs_tasks[i]);
1727 VERBOSE_PRINTK_ERRSTRING("Failed to create rcu_torture_barrier_cbs");
1728 barrier_cbs_tasks[i] = NULL;
1729 return ret;
1730 }
1731 }
1732 barrier_task = kthread_run(rcu_torture_barrier, NULL,
1733 "rcu_torture_barrier");
1734 if (IS_ERR(barrier_task)) {
1735 ret = PTR_ERR(barrier_task);
1736 VERBOSE_PRINTK_ERRSTRING("Failed to create rcu_torture_barrier");
1737 barrier_task = NULL;
1738 }
1739 return 0;
1740}
1741
1742/* Clean up after RCU barrier testing. */
1743static void rcu_torture_barrier_cleanup(void)
1744{
1745 int i;
1746
1747 if (barrier_task != NULL) {
1748 VERBOSE_PRINTK_STRING("Stopping rcu_torture_barrier task");
1749 kthread_stop(barrier_task);
1750 barrier_task = NULL;
1751 }
1752 if (barrier_cbs_tasks != NULL) {
1753 for (i = 0; i < n_barrier_cbs; i++) {
1754 if (barrier_cbs_tasks[i] != NULL) {
1755 VERBOSE_PRINTK_STRING("Stopping rcu_torture_barrier_cbs task");
1756 kthread_stop(barrier_cbs_tasks[i]);
1757 barrier_cbs_tasks[i] = NULL;
1758 }
1759 }
1760 kfree(barrier_cbs_tasks);
1761 barrier_cbs_tasks = NULL;
1762 }
1763 if (barrier_cbs_wq != NULL) {
1764 kfree(barrier_cbs_wq);
1765 barrier_cbs_wq = NULL;
1766 }
1767}
1768
1769static int rcutorture_cpu_notify(struct notifier_block *self,
1770 unsigned long action, void *hcpu)
1771{
1772 long cpu = (long)hcpu;
1773
1774 switch (action) {
1775 case CPU_ONLINE:
1776 case CPU_DOWN_FAILED:
1777 (void)rcutorture_booster_init(cpu);
1778 break;
1779 case CPU_DOWN_PREPARE:
1780 rcutorture_booster_cleanup(cpu);
1781 break;
1782 default:
1783 break;
1784 }
1785 return NOTIFY_OK;
1786}
1787
1788static struct notifier_block rcutorture_cpu_nb = {
1789 .notifier_call = rcutorture_cpu_notify,
1790};
1791
1792static void
1793rcu_torture_cleanup(void)
1794{
1795 int i;
1796
1797 mutex_lock(&fullstop_mutex);
1798 rcutorture_record_test_transition();
1799 if (fullstop == FULLSTOP_SHUTDOWN) {
1800 printk(KERN_WARNING /* but going down anyway, so... */
1801 "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
1802 mutex_unlock(&fullstop_mutex);
1803 schedule_timeout_uninterruptible(10);
1804 if (cur_ops->cb_barrier != NULL)
1805 cur_ops->cb_barrier();
1806 return;
1807 }
1808 fullstop = FULLSTOP_RMMOD;
1809 mutex_unlock(&fullstop_mutex);
1810 unregister_reboot_notifier(&rcutorture_shutdown_nb);
1811 rcu_torture_barrier_cleanup();
1812 rcu_torture_stall_cleanup();
1813 if (stutter_task) {
1814 VERBOSE_PRINTK_STRING("Stopping rcu_torture_stutter task");
1815 kthread_stop(stutter_task);
1816 }
1817 stutter_task = NULL;
1818 if (shuffler_task) {
1819 VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task");
1820 kthread_stop(shuffler_task);
1821 free_cpumask_var(shuffle_tmp_mask);
1822 }
1823 shuffler_task = NULL;
1824
1825 if (writer_task) {
1826 VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task");
1827 kthread_stop(writer_task);
1828 }
1829 writer_task = NULL;
1830
1831 if (reader_tasks) {
1832 for (i = 0; i < nrealreaders; i++) {
1833 if (reader_tasks[i]) {
1834 VERBOSE_PRINTK_STRING(
1835 "Stopping rcu_torture_reader task");
1836 kthread_stop(reader_tasks[i]);
1837 }
1838 reader_tasks[i] = NULL;
1839 }
1840 kfree(reader_tasks);
1841 reader_tasks = NULL;
1842 }
1843 rcu_torture_current = NULL;
1844
1845 if (fakewriter_tasks) {
1846 for (i = 0; i < nfakewriters; i++) {
1847 if (fakewriter_tasks[i]) {
1848 VERBOSE_PRINTK_STRING(
1849 "Stopping rcu_torture_fakewriter task");
1850 kthread_stop(fakewriter_tasks[i]);
1851 }
1852 fakewriter_tasks[i] = NULL;
1853 }
1854 kfree(fakewriter_tasks);
1855 fakewriter_tasks = NULL;
1856 }
1857
1858 if (stats_task) {
1859 VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task");
1860 kthread_stop(stats_task);
1861 }
1862 stats_task = NULL;
1863
1864 if (fqs_task) {
1865 VERBOSE_PRINTK_STRING("Stopping rcu_torture_fqs task");
1866 kthread_stop(fqs_task);
1867 }
1868 fqs_task = NULL;
1869 if ((test_boost == 1 && cur_ops->can_boost) ||
1870 test_boost == 2) {
1871 unregister_cpu_notifier(&rcutorture_cpu_nb);
1872 for_each_possible_cpu(i)
1873 rcutorture_booster_cleanup(i);
1874 }
1875 if (shutdown_task != NULL) {
1876 VERBOSE_PRINTK_STRING("Stopping rcu_torture_shutdown task");
1877 kthread_stop(shutdown_task);
1878 }
1879 shutdown_task = NULL;
1880 rcu_torture_onoff_cleanup();
1881
1882 /* Wait for all RCU callbacks to fire. */
1883
1884 if (cur_ops->cb_barrier != NULL)
1885 cur_ops->cb_barrier();
1886
1887 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
1888
1889 if (cur_ops->cleanup)
1890 cur_ops->cleanup();
1891 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
1892 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
1893 else if (n_online_successes != n_online_attempts ||
1894 n_offline_successes != n_offline_attempts)
1895 rcu_torture_print_module_parms(cur_ops,
1896 "End of test: RCU_HOTPLUG");
1897 else
1898 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
1899}
1900
1901static int __init
1902rcu_torture_init(void)
1903{
1904 int i;
1905 int cpu;
1906 int firsterr = 0;
1907 int retval;
1908 static struct rcu_torture_ops *torture_ops[] =
1909 { &rcu_ops, &rcu_sync_ops, &rcu_expedited_ops,
1910 &rcu_bh_ops, &rcu_bh_sync_ops, &rcu_bh_expedited_ops,
1911 &srcu_ops, &srcu_sync_ops, &srcu_raw_ops,
1912 &srcu_raw_sync_ops, &srcu_expedited_ops,
1913 &sched_ops, &sched_sync_ops, &sched_expedited_ops, };
1914
1915 mutex_lock(&fullstop_mutex);
1916
1917 /* Process args and tell the world that the torturer is on the job. */
1918 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1919 cur_ops = torture_ops[i];
1920 if (strcmp(torture_type, cur_ops->name) == 0)
1921 break;
1922 }
1923 if (i == ARRAY_SIZE(torture_ops)) {
1924 printk(KERN_ALERT "rcu-torture: invalid torture type: \"%s\"\n",
1925 torture_type);
1926 printk(KERN_ALERT "rcu-torture types:");
1927 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1928 printk(KERN_ALERT " %s", torture_ops[i]->name);
1929 printk(KERN_ALERT "\n");
1930 mutex_unlock(&fullstop_mutex);
1931 return -EINVAL;
1932 }
1933 if (cur_ops->fqs == NULL && fqs_duration != 0) {
1934 printk(KERN_ALERT "rcu-torture: ->fqs NULL and non-zero "
1935 "fqs_duration, fqs disabled.\n");
1936 fqs_duration = 0;
1937 }
1938 if (cur_ops->init)
1939 cur_ops->init(); /* no "goto unwind" prior to this point!!! */
1940
1941 if (nreaders >= 0)
1942 nrealreaders = nreaders;
1943 else
1944 nrealreaders = 2 * num_online_cpus();
1945 rcu_torture_print_module_parms(cur_ops, "Start of test");
1946 fullstop = FULLSTOP_DONTSTOP;
1947
1948 /* Set up the freelist. */
1949
1950 INIT_LIST_HEAD(&rcu_torture_freelist);
1951 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1952 rcu_tortures[i].rtort_mbtest = 0;
1953 list_add_tail(&rcu_tortures[i].rtort_free,
1954 &rcu_torture_freelist);
1955 }
1956
1957 /* Initialize the statistics so that each run gets its own numbers. */
1958
1959 rcu_torture_current = NULL;
1960 rcu_torture_current_version = 0;
1961 atomic_set(&n_rcu_torture_alloc, 0);
1962 atomic_set(&n_rcu_torture_alloc_fail, 0);
1963 atomic_set(&n_rcu_torture_free, 0);
1964 atomic_set(&n_rcu_torture_mberror, 0);
1965 atomic_set(&n_rcu_torture_error, 0);
1966 n_rcu_torture_barrier_error = 0;
1967 n_rcu_torture_boost_ktrerror = 0;
1968 n_rcu_torture_boost_rterror = 0;
1969 n_rcu_torture_boost_failure = 0;
1970 n_rcu_torture_boosts = 0;
1971 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1972 atomic_set(&rcu_torture_wcount[i], 0);
1973 for_each_possible_cpu(cpu) {
1974 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1975 per_cpu(rcu_torture_count, cpu)[i] = 0;
1976 per_cpu(rcu_torture_batch, cpu)[i] = 0;
1977 }
1978 }
1979
1980 /* Start up the kthreads. */
1981
1982 VERBOSE_PRINTK_STRING("Creating rcu_torture_writer task");
1983 writer_task = kthread_run(rcu_torture_writer, NULL,
1984 "rcu_torture_writer");
1985 if (IS_ERR(writer_task)) {
1986 firsterr = PTR_ERR(writer_task);
1987 VERBOSE_PRINTK_ERRSTRING("Failed to create writer");
1988 writer_task = NULL;
1989 goto unwind;
1990 }
1991 fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]),
1992 GFP_KERNEL);
1993 if (fakewriter_tasks == NULL) {
1994 VERBOSE_PRINTK_ERRSTRING("out of memory");
1995 firsterr = -ENOMEM;
1996 goto unwind;
1997 }
1998 for (i = 0; i < nfakewriters; i++) {
1999 VERBOSE_PRINTK_STRING("Creating rcu_torture_fakewriter task");
2000 fakewriter_tasks[i] = kthread_run(rcu_torture_fakewriter, NULL,
2001 "rcu_torture_fakewriter");
2002 if (IS_ERR(fakewriter_tasks[i])) {
2003 firsterr = PTR_ERR(fakewriter_tasks[i]);
2004 VERBOSE_PRINTK_ERRSTRING("Failed to create fakewriter");
2005 fakewriter_tasks[i] = NULL;
2006 goto unwind;
2007 }
2008 }
2009 reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
2010 GFP_KERNEL);
2011 if (reader_tasks == NULL) {
2012 VERBOSE_PRINTK_ERRSTRING("out of memory");
2013 firsterr = -ENOMEM;
2014 goto unwind;
2015 }
2016 for (i = 0; i < nrealreaders; i++) {
2017 VERBOSE_PRINTK_STRING("Creating rcu_torture_reader task");
2018 reader_tasks[i] = kthread_run(rcu_torture_reader, NULL,
2019 "rcu_torture_reader");
2020 if (IS_ERR(reader_tasks[i])) {
2021 firsterr = PTR_ERR(reader_tasks[i]);
2022 VERBOSE_PRINTK_ERRSTRING("Failed to create reader");
2023 reader_tasks[i] = NULL;
2024 goto unwind;
2025 }
2026 }
2027 if (stat_interval > 0) {
2028 VERBOSE_PRINTK_STRING("Creating rcu_torture_stats task");
2029 stats_task = kthread_run(rcu_torture_stats, NULL,
2030 "rcu_torture_stats");
2031 if (IS_ERR(stats_task)) {
2032 firsterr = PTR_ERR(stats_task);
2033 VERBOSE_PRINTK_ERRSTRING("Failed to create stats");
2034 stats_task = NULL;
2035 goto unwind;
2036 }
2037 }
2038 if (test_no_idle_hz) {
2039 rcu_idle_cpu = num_online_cpus() - 1;
2040
2041 if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
2042 firsterr = -ENOMEM;
2043 VERBOSE_PRINTK_ERRSTRING("Failed to alloc mask");
2044 goto unwind;
2045 }
2046
2047 /* Create the shuffler thread */
2048 shuffler_task = kthread_run(rcu_torture_shuffle, NULL,
2049 "rcu_torture_shuffle");
2050 if (IS_ERR(shuffler_task)) {
2051 free_cpumask_var(shuffle_tmp_mask);
2052 firsterr = PTR_ERR(shuffler_task);
2053 VERBOSE_PRINTK_ERRSTRING("Failed to create shuffler");
2054 shuffler_task = NULL;
2055 goto unwind;
2056 }
2057 }
2058 if (stutter < 0)
2059 stutter = 0;
2060 if (stutter) {
2061 /* Create the stutter thread */
2062 stutter_task = kthread_run(rcu_torture_stutter, NULL,
2063 "rcu_torture_stutter");
2064 if (IS_ERR(stutter_task)) {
2065 firsterr = PTR_ERR(stutter_task);
2066 VERBOSE_PRINTK_ERRSTRING("Failed to create stutter");
2067 stutter_task = NULL;
2068 goto unwind;
2069 }
2070 }
2071 if (fqs_duration < 0)
2072 fqs_duration = 0;
2073 if (fqs_duration) {
2074 /* Create the stutter thread */
2075 fqs_task = kthread_run(rcu_torture_fqs, NULL,
2076 "rcu_torture_fqs");
2077 if (IS_ERR(fqs_task)) {
2078 firsterr = PTR_ERR(fqs_task);
2079 VERBOSE_PRINTK_ERRSTRING("Failed to create fqs");
2080 fqs_task = NULL;
2081 goto unwind;
2082 }
2083 }
2084 if (test_boost_interval < 1)
2085 test_boost_interval = 1;
2086 if (test_boost_duration < 2)
2087 test_boost_duration = 2;
2088 if ((test_boost == 1 && cur_ops->can_boost) ||
2089 test_boost == 2) {
2090
2091 boost_starttime = jiffies + test_boost_interval * HZ;
2092 register_cpu_notifier(&rcutorture_cpu_nb);
2093 for_each_possible_cpu(i) {
2094 if (cpu_is_offline(i))
2095 continue; /* Heuristic: CPU can go offline. */
2096 retval = rcutorture_booster_init(i);
2097 if (retval < 0) {
2098 firsterr = retval;
2099 goto unwind;
2100 }
2101 }
2102 }
2103 if (shutdown_secs > 0) {
2104 shutdown_time = jiffies + shutdown_secs * HZ;
2105 shutdown_task = kthread_run(rcu_torture_shutdown, NULL,
2106 "rcu_torture_shutdown");
2107 if (IS_ERR(shutdown_task)) {
2108 firsterr = PTR_ERR(shutdown_task);
2109 VERBOSE_PRINTK_ERRSTRING("Failed to create shutdown");
2110 shutdown_task = NULL;
2111 goto unwind;
2112 }
2113 }
2114 i = rcu_torture_onoff_init();
2115 if (i != 0) {
2116 firsterr = i;
2117 goto unwind;
2118 }
2119 register_reboot_notifier(&rcutorture_shutdown_nb);
2120 i = rcu_torture_stall_init();
2121 if (i != 0) {
2122 firsterr = i;
2123 goto unwind;
2124 }
2125 retval = rcu_torture_barrier_init();
2126 if (retval != 0) {
2127 firsterr = retval;
2128 goto unwind;
2129 }
2130 rcutorture_record_test_transition();
2131 mutex_unlock(&fullstop_mutex);
2132 return 0;
2133
2134unwind:
2135 mutex_unlock(&fullstop_mutex);
2136 rcu_torture_cleanup();
2137 return firsterr;
2138}
2139
2140module_init(rcu_torture_init);
2141module_exit(rcu_torture_cleanup);