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Root/kernel/rcutorture.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 <asm/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
51	MODULE_LICENSE("GPL");
52	MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and "
53	"Josh Triplett <josh@freedesktop.org>");
54
55	static int nreaders = -1; /* # reader threads, defaults to 2ncpus /
56	static int nfakewriters = 4; /* # fake writer threads */
57	static int stat_interval; /* Interval between stats, in seconds. */
58	/* Defaults to "only at end of test". */
59	static int verbose; /* Print more debug info. */
60	static int test_no_idle_hz; /* Test RCU's support for tickless idle CPUs. */
61	static int shuffle_interval = 3; /* Interval between shuffles (in sec)*/
62	static int stutter = 5; /* Start/stop testing interval (in sec) */
63	static int irqreader = 1; /* RCU readers from irq (timers). */
64	static char torture_type = "rcu"; / What RCU implementation to torture. */
65
66	module_param(nreaders, int, 0444);
67	MODULE_PARM_DESC(nreaders, "Number of RCU reader threads");
68	module_param(nfakewriters, int, 0444);
69	MODULE_PARM_DESC(nfakewriters, "Number of RCU fake writer threads");
70	module_param(stat_interval, int, 0444);
71	MODULE_PARM_DESC(stat_interval, "Number of seconds between stats printk()s");
72	module_param(verbose, bool, 0444);
73	MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s");
74	module_param(test_no_idle_hz, bool, 0444);
75	MODULE_PARM_DESC(test_no_idle_hz, "Test support for tickless idle CPUs");
76	module_param(shuffle_interval, int, 0444);
77	MODULE_PARM_DESC(shuffle_interval, "Number of seconds between shuffles");
78	module_param(stutter, int, 0444);
79	MODULE_PARM_DESC(stutter, "Number of seconds to run/halt test");
80	module_param(irqreader, int, 0444);
81	MODULE_PARM_DESC(irqreader, "Allow RCU readers from irq handlers");
82	module_param(torture_type, charp, 0444);
83	MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, srcu)");
84
85	#define TORTURE_FLAG "-torture:"
86	#define PRINTK_STRING(s) \
87	do { printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
88	#define VERBOSE_PRINTK_STRING(s) \
89	do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
90	#define VERBOSE_PRINTK_ERRSTRING(s) \
91	do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG "!!! " s "\n", torture_type); } while (0)
92
93	static char printk_buf[4096];
94
95	static int nrealreaders;
96	static struct task_struct *writer_task;
97	static struct task_struct **fakewriter_tasks;
98	static struct task_struct **reader_tasks;
99	static struct task_struct *stats_task;
100	static struct task_struct *shuffler_task;
101	static struct task_struct *stutter_task;
102
103	#define RCU_TORTURE_PIPE_LEN 10
104
105	struct rcu_torture {
106	struct rcu_head rtort_rcu;
107	int rtort_pipe_count;
108	struct list_head rtort_free;
109	int rtort_mbtest;
110	};
111
112	static LIST_HEAD(rcu_torture_freelist);
113	static struct rcu_torture *rcu_torture_current;
114	static long rcu_torture_current_version;
115	static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
116	static DEFINE_SPINLOCK(rcu_torture_lock);
117	static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) =
118	{ 0 };
119	static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) =
120	{ 0 };
121	static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
122	static atomic_t n_rcu_torture_alloc;
123	static atomic_t n_rcu_torture_alloc_fail;
124	static atomic_t n_rcu_torture_free;
125	static atomic_t n_rcu_torture_mberror;
126	static atomic_t n_rcu_torture_error;
127	static long n_rcu_torture_timers;
128	static struct list_head rcu_torture_removed;
129	static cpumask_var_t shuffle_tmp_mask;
130
131	static int stutter_pause_test;
132
133	#if defined(MODULE) \|\| defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
134	#define RCUTORTURE_RUNNABLE_INIT 1
135	#else
136	#define RCUTORTURE_RUNNABLE_INIT 0
137	#endif
138	int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT;
139
140	/* Mediate rmmod and system shutdown. Concurrent rmmod & shutdown illegal! */
141
142	#define FULLSTOP_DONTSTOP 0 /* Normal operation. */
143	#define FULLSTOP_SHUTDOWN 1 /* System shutdown with rcutorture running. */
144	#define FULLSTOP_RMMOD 2 /* Normal rmmod of rcutorture. */
145	static int fullstop = FULLSTOP_RMMOD;
146	DEFINE_MUTEX(fullstop_mutex); /* Protect fullstop transitions and spawning */
147	/* of kthreads. */
148
149	/*
150	* Detect and respond to a system shutdown.
151	*/
152	static int
153	rcutorture_shutdown_notify(struct notifier_block *unused1,
154	unsigned long unused2, void *unused3)
155	{
156	mutex_lock(&fullstop_mutex);
157	if (fullstop == FULLSTOP_DONTSTOP)
158	fullstop = FULLSTOP_SHUTDOWN;
159	else
160	printk(KERN_WARNING /* but going down anyway, so... */
161	"Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
162	mutex_unlock(&fullstop_mutex);
163	return NOTIFY_DONE;
164	}
165
166	/*
167	* Absorb kthreads into a kernel function that won't return, so that
168	* they won't ever access module text or data again.
169	*/
170	static void rcutorture_shutdown_absorb(char *title)
171	{
172	if (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
173	printk(KERN_NOTICE
174	"rcutorture thread %s parking due to system shutdown\n",
175	title);
176	schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
177	}
178	}
179
180	/*
181	* Allocate an element from the rcu_tortures pool.
182	*/
183	static struct rcu_torture *
184	rcu_torture_alloc(void)
185	{
186	struct list_head *p;
187
188	spin_lock_bh(&rcu_torture_lock);
189	if (list_empty(&rcu_torture_freelist)) {
190	atomic_inc(&n_rcu_torture_alloc_fail);
191	spin_unlock_bh(&rcu_torture_lock);
192	return NULL;
193	}
194	atomic_inc(&n_rcu_torture_alloc);
195	p = rcu_torture_freelist.next;
196	list_del_init(p);
197	spin_unlock_bh(&rcu_torture_lock);
198	return container_of(p, struct rcu_torture, rtort_free);
199	}
200
201	/*
202	* Free an element to the rcu_tortures pool.
203	*/
204	static void
205	rcu_torture_free(struct rcu_torture *p)
206	{
207	atomic_inc(&n_rcu_torture_free);
208	spin_lock_bh(&rcu_torture_lock);
209	list_add_tail(&p->rtort_free, &rcu_torture_freelist);
210	spin_unlock_bh(&rcu_torture_lock);
211	}
212
213	struct rcu_random_state {
214	unsigned long rrs_state;
215	long rrs_count;
216	};
217
218	#define RCU_RANDOM_MULT 39916801 /* prime */
219	#define RCU_RANDOM_ADD 479001701 /* prime */
220	#define RCU_RANDOM_REFRESH 10000
221
222	#define DEFINE_RCU_RANDOM(name) struct rcu_random_state name = { 0, 0 }
223
224	/*
225	* Crude but fast random-number generator. Uses a linear congruential
226	* generator, with occasional help from cpu_clock().
227	*/
228	static unsigned long
229	rcu_random(struct rcu_random_state *rrsp)
230	{
231	if (--rrsp->rrs_count < 0) {
232	rrsp->rrs_state +=
233	(unsigned long)cpu_clock(raw_smp_processor_id());
234	rrsp->rrs_count = RCU_RANDOM_REFRESH;
235	}
236	rrsp->rrs_state = rrsp->rrs_state * RCU_RANDOM_MULT + RCU_RANDOM_ADD;
237	return swahw32(rrsp->rrs_state);
238	}
239
240	static void
241	rcu_stutter_wait(char *title)
242	{
243	while (stutter_pause_test \|\| !rcutorture_runnable) {
244	if (rcutorture_runnable)
245	schedule_timeout_interruptible(1);
246	else
247	schedule_timeout_interruptible(round_jiffies_relative(HZ));
248	rcutorture_shutdown_absorb(title);
249	}
250	}
251
252	/*
253	* Operations vector for selecting different types of tests.
254	*/
255
256	struct rcu_torture_ops {
257	void (*init)(void);
258	void (*cleanup)(void);
259	int (*readlock)(void);
260	void (read_delay)(struct rcu_random_state rrsp);
261	void (*readunlock)(int idx);
262	int (*completed)(void);
263	void (deferred_free)(struct rcu_torture p);
264	void (*sync)(void);
265	void (*cb_barrier)(void);
266	int (stats)(char page);
267	int irq_capable;
268	char *name;
269	};
270
271	static struct rcu_torture_ops *cur_ops;
272
273	/*
274	* Definitions for rcu torture testing.
275	*/
276
277	static int rcu_torture_read_lock(void) __acquires(RCU)
278	{
279	rcu_read_lock();
280	return 0;
281	}
282
283	static void rcu_read_delay(struct rcu_random_state *rrsp)
284	{
285	const unsigned long shortdelay_us = 200;
286	const unsigned long longdelay_ms = 50;
287
288	/* We want a short delay sometimes to make a reader delay the grace
289	* period, and we want a long delay occasionally to trigger
290	* force_quiescent_state. */
291
292	if (!(rcu_random(rrsp) % (nrealreaders * 2000 * longdelay_ms)))
293	mdelay(longdelay_ms);
294	if (!(rcu_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
295	udelay(shortdelay_us);
296	}
297
298	static void rcu_torture_read_unlock(int idx) __releases(RCU)
299	{
300	rcu_read_unlock();
301	}
302
303	static int rcu_torture_completed(void)
304	{
305	return rcu_batches_completed();
306	}
307
308	static void
309	rcu_torture_cb(struct rcu_head *p)
310	{
311	int i;
312	struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
313
314	if (fullstop != FULLSTOP_DONTSTOP) {
315	/* Test is ending, just drop callbacks on the floor. */
316	/* The next initialization will pick up the pieces. */
317	return;
318	}
319	i = rp->rtort_pipe_count;
320	if (i > RCU_TORTURE_PIPE_LEN)
321	i = RCU_TORTURE_PIPE_LEN;
322	atomic_inc(&rcu_torture_wcount[i]);
323	if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
324	rp->rtort_mbtest = 0;
325	rcu_torture_free(rp);
326	} else
327	cur_ops->deferred_free(rp);
328	}
329
330	static void rcu_torture_deferred_free(struct rcu_torture *p)
331	{
332	call_rcu(&p->rtort_rcu, rcu_torture_cb);
333	}
334
335	static struct rcu_torture_ops rcu_ops = {
336	.init = NULL,
337	.cleanup = NULL,
338	.readlock = rcu_torture_read_lock,
339	.read_delay = rcu_read_delay,
340	.readunlock = rcu_torture_read_unlock,
341	.completed = rcu_torture_completed,
342	.deferred_free = rcu_torture_deferred_free,
343	.sync = synchronize_rcu,
344	.cb_barrier = rcu_barrier,
345	.stats = NULL,
346	.irq_capable = 1,
347	.name = "rcu"
348	};
349
350	static void rcu_sync_torture_deferred_free(struct rcu_torture *p)
351	{
352	int i;
353	struct rcu_torture *rp;
354	struct rcu_torture *rp1;
355
356	cur_ops->sync();
357	list_add(&p->rtort_free, &rcu_torture_removed);
358	list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
359	i = rp->rtort_pipe_count;
360	if (i > RCU_TORTURE_PIPE_LEN)
361	i = RCU_TORTURE_PIPE_LEN;
362	atomic_inc(&rcu_torture_wcount[i]);
363	if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
364	rp->rtort_mbtest = 0;
365	list_del(&rp->rtort_free);
366	rcu_torture_free(rp);
367	}
368	}
369	}
370
371	static void rcu_sync_torture_init(void)
372	{
373	INIT_LIST_HEAD(&rcu_torture_removed);
374	}
375
376	static struct rcu_torture_ops rcu_sync_ops = {
377	.init = rcu_sync_torture_init,
378	.cleanup = NULL,
379	.readlock = rcu_torture_read_lock,
380	.read_delay = rcu_read_delay,
381	.readunlock = rcu_torture_read_unlock,
382	.completed = rcu_torture_completed,
383	.deferred_free = rcu_sync_torture_deferred_free,
384	.sync = synchronize_rcu,
385	.cb_barrier = NULL,
386	.stats = NULL,
387	.irq_capable = 1,
388	.name = "rcu_sync"
389	};
390
391	/*
392	* Definitions for rcu_bh torture testing.
393	*/
394
395	static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
396	{
397	rcu_read_lock_bh();
398	return 0;
399	}
400
401	static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
402	{
403	rcu_read_unlock_bh();
404	}
405
406	static int rcu_bh_torture_completed(void)
407	{
408	return rcu_batches_completed_bh();
409	}
410
411	static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
412	{
413	call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
414	}
415
416	struct rcu_bh_torture_synchronize {
417	struct rcu_head head;
418	struct completion completion;
419	};
420
421	static void rcu_bh_torture_wakeme_after_cb(struct rcu_head *head)
422	{
423	struct rcu_bh_torture_synchronize *rcu;
424
425	rcu = container_of(head, struct rcu_bh_torture_synchronize, head);
426	complete(&rcu->completion);
427	}
428
429	static void rcu_bh_torture_synchronize(void)
430	{
431	struct rcu_bh_torture_synchronize rcu;
432
433	init_completion(&rcu.completion);
434	call_rcu_bh(&rcu.head, rcu_bh_torture_wakeme_after_cb);
435	wait_for_completion(&rcu.completion);
436	}
437
438	static struct rcu_torture_ops rcu_bh_ops = {
439	.init = NULL,
440	.cleanup = NULL,
441	.readlock = rcu_bh_torture_read_lock,
442	.read_delay = rcu_read_delay, /* just reuse rcu's version. */
443	.readunlock = rcu_bh_torture_read_unlock,
444	.completed = rcu_bh_torture_completed,
445	.deferred_free = rcu_bh_torture_deferred_free,
446	.sync = rcu_bh_torture_synchronize,
447	.cb_barrier = rcu_barrier_bh,
448	.stats = NULL,
449	.irq_capable = 1,
450	.name = "rcu_bh"
451	};
452
453	static struct rcu_torture_ops rcu_bh_sync_ops = {
454	.init = rcu_sync_torture_init,
455	.cleanup = NULL,
456	.readlock = rcu_bh_torture_read_lock,
457	.read_delay = rcu_read_delay, /* just reuse rcu's version. */
458	.readunlock = rcu_bh_torture_read_unlock,
459	.completed = rcu_bh_torture_completed,
460	.deferred_free = rcu_sync_torture_deferred_free,
461	.sync = rcu_bh_torture_synchronize,
462	.cb_barrier = NULL,
463	.stats = NULL,
464	.irq_capable = 1,
465	.name = "rcu_bh_sync"
466	};
467
468	/*
469	* Definitions for srcu torture testing.
470	*/
471
472	static struct srcu_struct srcu_ctl;
473
474	static void srcu_torture_init(void)
475	{
476	init_srcu_struct(&srcu_ctl);
477	rcu_sync_torture_init();
478	}
479
480	static void srcu_torture_cleanup(void)
481	{
482	synchronize_srcu(&srcu_ctl);
483	cleanup_srcu_struct(&srcu_ctl);
484	}
485
486	static int srcu_torture_read_lock(void) __acquires(&srcu_ctl)
487	{
488	return srcu_read_lock(&srcu_ctl);
489	}
490
491	static void srcu_read_delay(struct rcu_random_state *rrsp)
492	{
493	long delay;
494	const long uspertick = 1000000 / HZ;
495	const long longdelay = 10;
496
497	/* We want there to be long-running readers, but not all the time. */
498
499	delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay * uspertick);
500	if (!delay)
501	schedule_timeout_interruptible(longdelay);
502	}
503
504	static void srcu_torture_read_unlock(int idx) __releases(&srcu_ctl)
505	{
506	srcu_read_unlock(&srcu_ctl, idx);
507	}
508
509	static int srcu_torture_completed(void)
510	{
511	return srcu_batches_completed(&srcu_ctl);
512	}
513
514	static void srcu_torture_synchronize(void)
515	{
516	synchronize_srcu(&srcu_ctl);
517	}
518
519	static int srcu_torture_stats(char *page)
520	{
521	int cnt = 0;
522	int cpu;
523	int idx = srcu_ctl.completed & 0x1;
524
525	cnt += sprintf(&page[cnt], "%s%s per-CPU(idx=%d):",
526	torture_type, TORTURE_FLAG, idx);
527	for_each_possible_cpu(cpu) {
528	cnt += sprintf(&page[cnt], " %d(%d,%d)", cpu,
529	per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx],
530	per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx]);
531	}
532	cnt += sprintf(&page[cnt], "\n");
533	return cnt;
534	}
535
536	static struct rcu_torture_ops srcu_ops = {
537	.init = srcu_torture_init,
538	.cleanup = srcu_torture_cleanup,
539	.readlock = srcu_torture_read_lock,
540	.read_delay = srcu_read_delay,
541	.readunlock = srcu_torture_read_unlock,
542	.completed = srcu_torture_completed,
543	.deferred_free = rcu_sync_torture_deferred_free,
544	.sync = srcu_torture_synchronize,
545	.cb_barrier = NULL,
546	.stats = srcu_torture_stats,
547	.name = "srcu"
548	};
549
550	/*
551	* Definitions for sched torture testing.
552	*/
553
554	static int sched_torture_read_lock(void)
555	{
556	preempt_disable();
557	return 0;
558	}
559
560	static void sched_torture_read_unlock(int idx)
561	{
562	preempt_enable();
563	}
564
565	static int sched_torture_completed(void)
566	{
567	return 0;
568	}
569
570	static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
571	{
572	call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
573	}
574
575	static void sched_torture_synchronize(void)
576	{
577	synchronize_sched();
578	}
579
580	static struct rcu_torture_ops sched_ops = {
581	.init = rcu_sync_torture_init,
582	.cleanup = NULL,
583	.readlock = sched_torture_read_lock,
584	.read_delay = rcu_read_delay, /* just reuse rcu's version. */
585	.readunlock = sched_torture_read_unlock,
586	.completed = sched_torture_completed,
587	.deferred_free = rcu_sched_torture_deferred_free,
588	.sync = sched_torture_synchronize,
589	.cb_barrier = rcu_barrier_sched,
590	.stats = NULL,
591	.irq_capable = 1,
592	.name = "sched"
593	};
594
595	static struct rcu_torture_ops sched_ops_sync = {
596	.init = rcu_sync_torture_init,
597	.cleanup = NULL,
598	.readlock = sched_torture_read_lock,
599	.read_delay = rcu_read_delay, /* just reuse rcu's version. */
600	.readunlock = sched_torture_read_unlock,
601	.completed = sched_torture_completed,
602	.deferred_free = rcu_sync_torture_deferred_free,
603	.sync = sched_torture_synchronize,
604	.cb_barrier = NULL,
605	.stats = NULL,
606	.name = "sched_sync"
607	};
608
609	static struct rcu_torture_ops sched_expedited_ops = {
610	.init = rcu_sync_torture_init,
611	.cleanup = NULL,
612	.readlock = sched_torture_read_lock,
613	.read_delay = rcu_read_delay, /* just reuse rcu's version. */
614	.readunlock = sched_torture_read_unlock,
615	.completed = sched_torture_completed,
616	.deferred_free = rcu_sync_torture_deferred_free,
617	.sync = synchronize_sched_expedited,
618	.cb_barrier = NULL,
619	.stats = rcu_expedited_torture_stats,
620	.irq_capable = 1,
621	.name = "sched_expedited"
622	};
623
624	/*
625	* RCU torture writer kthread. Repeatedly substitutes a new structure
626	* for that pointed to by rcu_torture_current, freeing the old structure
627	* after a series of grace periods (the "pipeline").
628	*/
629	static int
630	rcu_torture_writer(void *arg)
631	{
632	int i;
633	long oldbatch = rcu_batches_completed();
634	struct rcu_torture *rp;
635	struct rcu_torture *old_rp;
636	static DEFINE_RCU_RANDOM(rand);
637
638	VERBOSE_PRINTK_STRING("rcu_torture_writer task started");
639	set_user_nice(current, 19);
640
641	do {
642	schedule_timeout_uninterruptible(1);
643	rp = rcu_torture_alloc();
644	if (rp == NULL)
645	continue;
646	rp->rtort_pipe_count = 0;
647	udelay(rcu_random(&rand) & 0x3ff);
648	old_rp = rcu_torture_current;
649	rp->rtort_mbtest = 1;
650	rcu_assign_pointer(rcu_torture_current, rp);
651	smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
652	if (old_rp) {
653	i = old_rp->rtort_pipe_count;
654	if (i > RCU_TORTURE_PIPE_LEN)
655	i = RCU_TORTURE_PIPE_LEN;
656	atomic_inc(&rcu_torture_wcount[i]);
657	old_rp->rtort_pipe_count++;
658	cur_ops->deferred_free(old_rp);
659	}
660	rcu_torture_current_version++;
661	oldbatch = cur_ops->completed();
662	rcu_stutter_wait("rcu_torture_writer");
663	} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
664	VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
665	rcutorture_shutdown_absorb("rcu_torture_writer");
666	while (!kthread_should_stop())
667	schedule_timeout_uninterruptible(1);
668	return 0;
669	}
670
671	/*
672	* RCU torture fake writer kthread. Repeatedly calls sync, with a random
673	* delay between calls.
674	*/
675	static int
676	rcu_torture_fakewriter(void *arg)
677	{
678	DEFINE_RCU_RANDOM(rand);
679
680	VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started");
681	set_user_nice(current, 19);
682
683	do {
684	schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10);
685	udelay(rcu_random(&rand) & 0x3ff);
686	cur_ops->sync();
687	rcu_stutter_wait("rcu_torture_fakewriter");
688	} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
689
690	VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
691	rcutorture_shutdown_absorb("rcu_torture_fakewriter");
692	while (!kthread_should_stop())
693	schedule_timeout_uninterruptible(1);
694	return 0;
695	}
696
697	/*
698	* RCU torture reader from timer handler. Dereferences rcu_torture_current,
699	* incrementing the corresponding element of the pipeline array. The
700	* counter in the element should never be greater than 1, otherwise, the
701	* RCU implementation is broken.
702	*/
703	static void rcu_torture_timer(unsigned long unused)
704	{
705	int idx;
706	int completed;
707	static DEFINE_RCU_RANDOM(rand);
708	static DEFINE_SPINLOCK(rand_lock);
709	struct rcu_torture *p;
710	int pipe_count;
711
712	idx = cur_ops->readlock();
713	completed = cur_ops->completed();
714	p = rcu_dereference(rcu_torture_current);
715	if (p == NULL) {
716	/* Leave because rcu_torture_writer is not yet underway */
717	cur_ops->readunlock(idx);
718	return;
719	}
720	if (p->rtort_mbtest == 0)
721	atomic_inc(&n_rcu_torture_mberror);
722	spin_lock(&rand_lock);
723	cur_ops->read_delay(&rand);
724	n_rcu_torture_timers++;
725	spin_unlock(&rand_lock);
726	preempt_disable();
727	pipe_count = p->rtort_pipe_count;
728	if (pipe_count > RCU_TORTURE_PIPE_LEN) {
729	/* Should not happen, but... */
730	pipe_count = RCU_TORTURE_PIPE_LEN;
731	}
732	++__get_cpu_var(rcu_torture_count)[pipe_count];
733	completed = cur_ops->completed() - completed;
734	if (completed > RCU_TORTURE_PIPE_LEN) {
735	/* Should not happen, but... */
736	completed = RCU_TORTURE_PIPE_LEN;
737	}
738	++__get_cpu_var(rcu_torture_batch)[completed];
739	preempt_enable();
740	cur_ops->readunlock(idx);
741	}
742
743	/*
744	* RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
745	* incrementing the corresponding element of the pipeline array. The
746	* counter in the element should never be greater than 1, otherwise, the
747	* RCU implementation is broken.
748	*/
749	static int
750	rcu_torture_reader(void *arg)
751	{
752	int completed;
753	int idx;
754	DEFINE_RCU_RANDOM(rand);
755	struct rcu_torture *p;
756	int pipe_count;
757	struct timer_list t;
758
759	VERBOSE_PRINTK_STRING("rcu_torture_reader task started");
760	set_user_nice(current, 19);
761	if (irqreader && cur_ops->irq_capable)
762	setup_timer_on_stack(&t, rcu_torture_timer, 0);
763
764	do {
765	if (irqreader && cur_ops->irq_capable) {
766	if (!timer_pending(&t))
767	mod_timer(&t, 1);
768	}
769	idx = cur_ops->readlock();
770	completed = cur_ops->completed();
771	p = rcu_dereference(rcu_torture_current);
772	if (p == NULL) {
773	/* Wait for rcu_torture_writer to get underway */
774	cur_ops->readunlock(idx);
775	schedule_timeout_interruptible(HZ);
776	continue;
777	}
778	if (p->rtort_mbtest == 0)
779	atomic_inc(&n_rcu_torture_mberror);
780	cur_ops->read_delay(&rand);
781	preempt_disable();
782	pipe_count = p->rtort_pipe_count;
783	if (pipe_count > RCU_TORTURE_PIPE_LEN) {
784	/* Should not happen, but... */
785	pipe_count = RCU_TORTURE_PIPE_LEN;
786	}
787	++__get_cpu_var(rcu_torture_count)[pipe_count];
788	completed = cur_ops->completed() - completed;
789	if (completed > RCU_TORTURE_PIPE_LEN) {
790	/* Should not happen, but... */
791	completed = RCU_TORTURE_PIPE_LEN;
792	}
793	++__get_cpu_var(rcu_torture_batch)[completed];
794	preempt_enable();
795	cur_ops->readunlock(idx);
796	schedule();
797	rcu_stutter_wait("rcu_torture_reader");
798	} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
799	VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
800	rcutorture_shutdown_absorb("rcu_torture_reader");
801	if (irqreader && cur_ops->irq_capable)
802	del_timer_sync(&t);
803	while (!kthread_should_stop())
804	schedule_timeout_uninterruptible(1);
805	return 0;
806	}
807
808	/*
809	* Create an RCU-torture statistics message in the specified buffer.
810	*/
811	static int
812	rcu_torture_printk(char *page)
813	{
814	int cnt = 0;
815	int cpu;
816	int i;
817	long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
818	long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
819
820	for_each_possible_cpu(cpu) {
821	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
822	pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
823	batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
824	}
825	}
826	for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
827	if (pipesummary[i] != 0)
828	break;
829	}
830	cnt += sprintf(&page[cnt], "%s%s ", torture_type, TORTURE_FLAG);
831	cnt += sprintf(&page[cnt],
832	"rtc: %p ver: %ld tfle: %d rta: %d rtaf: %d rtf: %d "
833	"rtmbe: %d nt: %ld",
834	rcu_torture_current,
835	rcu_torture_current_version,
836	list_empty(&rcu_torture_freelist),
837	atomic_read(&n_rcu_torture_alloc),
838	atomic_read(&n_rcu_torture_alloc_fail),
839	atomic_read(&n_rcu_torture_free),
840	atomic_read(&n_rcu_torture_mberror),
841	n_rcu_torture_timers);
842	if (atomic_read(&n_rcu_torture_mberror) != 0)
843	cnt += sprintf(&page[cnt], " !!!");
844	cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
845	if (i > 1) {
846	cnt += sprintf(&page[cnt], "!!! ");
847	atomic_inc(&n_rcu_torture_error);
848	WARN_ON_ONCE(1);
849	}
850	cnt += sprintf(&page[cnt], "Reader Pipe: ");
851	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
852	cnt += sprintf(&page[cnt], " %ld", pipesummary[i]);
853	cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
854	cnt += sprintf(&page[cnt], "Reader Batch: ");
855	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
856	cnt += sprintf(&page[cnt], " %ld", batchsummary[i]);
857	cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
858	cnt += sprintf(&page[cnt], "Free-Block Circulation: ");
859	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
860	cnt += sprintf(&page[cnt], " %d",
861	atomic_read(&rcu_torture_wcount[i]));
862	}
863	cnt += sprintf(&page[cnt], "\n");
864	if (cur_ops->stats)
865	cnt += cur_ops->stats(&page[cnt]);
866	return cnt;
867	}
868
869	/*
870	* Print torture statistics. Caller must ensure that there is only
871	* one call to this function at a given time!!! This is normally
872	* accomplished by relying on the module system to only have one copy
873	* of the module loaded, and then by giving the rcu_torture_stats
874	* kthread full control (or the init/cleanup functions when rcu_torture_stats
875	* thread is not running).
876	*/
877	static void
878	rcu_torture_stats_print(void)
879	{
880	int cnt;
881
882	cnt = rcu_torture_printk(printk_buf);
883	printk(KERN_ALERT "%s", printk_buf);
884	}
885
886	/*
887	* Periodically prints torture statistics, if periodic statistics printing
888	* was specified via the stat_interval module parameter.
889	*
890	* No need to worry about fullstop here, since this one doesn't reference
891	* volatile state or register callbacks.
892	*/
893	static int
894	rcu_torture_stats(void *arg)
895	{
896	VERBOSE_PRINTK_STRING("rcu_torture_stats task started");
897	do {
898	schedule_timeout_interruptible(stat_interval * HZ);
899	rcu_torture_stats_print();
900	rcutorture_shutdown_absorb("rcu_torture_stats");
901	} while (!kthread_should_stop());
902	VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping");
903	return 0;
904	}
905
906	static int rcu_idle_cpu; /* Force all torture tasks off this CPU */
907
908	/* Shuffle tasks such that we allow @rcu_idle_cpu to become idle. A special case
909	* is when @rcu_idle_cpu = -1, when we allow the tasks to run on all CPUs.
910	*/
911	static void rcu_torture_shuffle_tasks(void)
912	{
913	int i;
914
915	cpumask_setall(shuffle_tmp_mask);
916	get_online_cpus();
917
918	/* No point in shuffling if there is only one online CPU (ex: UP) */
919	if (num_online_cpus() == 1) {
920	put_online_cpus();
921	return;
922	}
923
924	if (rcu_idle_cpu != -1)
925	cpumask_clear_cpu(rcu_idle_cpu, shuffle_tmp_mask);
926
927	set_cpus_allowed_ptr(current, shuffle_tmp_mask);
928
929	if (reader_tasks) {
930	for (i = 0; i < nrealreaders; i++)
931	if (reader_tasks[i])
932	set_cpus_allowed_ptr(reader_tasks[i],
933	shuffle_tmp_mask);
934	}
935
936	if (fakewriter_tasks) {
937	for (i = 0; i < nfakewriters; i++)
938	if (fakewriter_tasks[i])
939	set_cpus_allowed_ptr(fakewriter_tasks[i],
940	shuffle_tmp_mask);
941	}
942
943	if (writer_task)
944	set_cpus_allowed_ptr(writer_task, shuffle_tmp_mask);
945
946	if (stats_task)
947	set_cpus_allowed_ptr(stats_task, shuffle_tmp_mask);
948
949	if (rcu_idle_cpu == -1)
950	rcu_idle_cpu = num_online_cpus() - 1;
951	else
952	rcu_idle_cpu--;
953
954	put_online_cpus();
955	}
956
957	/* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
958	* system to become idle at a time and cut off its timer ticks. This is meant
959	* to test the support for such tickless idle CPU in RCU.
960	*/
961	static int
962	rcu_torture_shuffle(void *arg)
963	{
964	VERBOSE_PRINTK_STRING("rcu_torture_shuffle task started");
965	do {
966	schedule_timeout_interruptible(shuffle_interval * HZ);
967	rcu_torture_shuffle_tasks();
968	rcutorture_shutdown_absorb("rcu_torture_shuffle");
969	} while (!kthread_should_stop());
970	VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping");
971	return 0;
972	}
973
974	/* Cause the rcutorture test to "stutter", starting and stopping all
975	* threads periodically.
976	*/
977	static int
978	rcu_torture_stutter(void *arg)
979	{
980	VERBOSE_PRINTK_STRING("rcu_torture_stutter task started");
981	do {
982	schedule_timeout_interruptible(stutter * HZ);
983	stutter_pause_test = 1;
984	if (!kthread_should_stop())
985	schedule_timeout_interruptible(stutter * HZ);
986	stutter_pause_test = 0;
987	rcutorture_shutdown_absorb("rcu_torture_stutter");
988	} while (!kthread_should_stop());
989	VERBOSE_PRINTK_STRING("rcu_torture_stutter task stopping");
990	return 0;
991	}
992
993	static inline void
994	rcu_torture_print_module_parms(char *tag)
995	{
996	printk(KERN_ALERT "%s" TORTURE_FLAG
997	"--- %s: nreaders=%d nfakewriters=%d "
998	"stat_interval=%d verbose=%d test_no_idle_hz=%d "
999	"shuffle_interval=%d stutter=%d irqreader=%d\n",
1000	torture_type, tag, nrealreaders, nfakewriters,
1001	stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1002	stutter, irqreader);
1003	}
1004
1005	static struct notifier_block rcutorture_nb = {
1006	.notifier_call = rcutorture_shutdown_notify,
1007	};
1008
1009	static void
1010	rcu_torture_cleanup(void)
1011	{
1012	int i;
1013
1014	mutex_lock(&fullstop_mutex);
1015	if (fullstop == FULLSTOP_SHUTDOWN) {
1016	printk(KERN_WARNING /* but going down anyway, so... */
1017	"Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
1018	mutex_unlock(&fullstop_mutex);
1019	schedule_timeout_uninterruptible(10);
1020	if (cur_ops->cb_barrier != NULL)
1021	cur_ops->cb_barrier();
1022	return;
1023	}
1024	fullstop = FULLSTOP_RMMOD;
1025	mutex_unlock(&fullstop_mutex);
1026	unregister_reboot_notifier(&rcutorture_nb);
1027	if (stutter_task) {
1028	VERBOSE_PRINTK_STRING("Stopping rcu_torture_stutter task");
1029	kthread_stop(stutter_task);
1030	}
1031	stutter_task = NULL;
1032	if (shuffler_task) {
1033	VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task");
1034	kthread_stop(shuffler_task);
1035	free_cpumask_var(shuffle_tmp_mask);
1036	}
1037	shuffler_task = NULL;
1038
1039	if (writer_task) {
1040	VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task");
1041	kthread_stop(writer_task);
1042	}
1043	writer_task = NULL;
1044
1045	if (reader_tasks) {
1046	for (i = 0; i < nrealreaders; i++) {
1047	if (reader_tasks[i]) {
1048	VERBOSE_PRINTK_STRING(
1049	"Stopping rcu_torture_reader task");
1050	kthread_stop(reader_tasks[i]);
1051	}
1052	reader_tasks[i] = NULL;
1053	}
1054	kfree(reader_tasks);
1055	reader_tasks = NULL;
1056	}
1057	rcu_torture_current = NULL;
1058
1059	if (fakewriter_tasks) {
1060	for (i = 0; i < nfakewriters; i++) {
1061	if (fakewriter_tasks[i]) {
1062	VERBOSE_PRINTK_STRING(
1063	"Stopping rcu_torture_fakewriter task");
1064	kthread_stop(fakewriter_tasks[i]);
1065	}
1066	fakewriter_tasks[i] = NULL;
1067	}
1068	kfree(fakewriter_tasks);
1069	fakewriter_tasks = NULL;
1070	}
1071
1072	if (stats_task) {
1073	VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task");
1074	kthread_stop(stats_task);
1075	}
1076	stats_task = NULL;
1077
1078	/* Wait for all RCU callbacks to fire. */
1079
1080	if (cur_ops->cb_barrier != NULL)
1081	cur_ops->cb_barrier();
1082
1083	rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
1084
1085	if (cur_ops->cleanup)
1086	cur_ops->cleanup();
1087	if (atomic_read(&n_rcu_torture_error))
1088	rcu_torture_print_module_parms("End of test: FAILURE");
1089	else
1090	rcu_torture_print_module_parms("End of test: SUCCESS");
1091	}
1092
1093	static int __init
1094	rcu_torture_init(void)
1095	{
1096	int i;
1097	int cpu;
1098	int firsterr = 0;
1099	static struct rcu_torture_ops *torture_ops[] =
1100	{ &rcu_ops, &rcu_sync_ops, &rcu_bh_ops, &rcu_bh_sync_ops,
1101	&sched_expedited_ops,
1102	&srcu_ops, &sched_ops, &sched_ops_sync, };
1103
1104	mutex_lock(&fullstop_mutex);
1105
1106	/* Process args and tell the world that the torturer is on the job. */
1107	for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1108	cur_ops = torture_ops[i];
1109	if (strcmp(torture_type, cur_ops->name) == 0)
1110	break;
1111	}
1112	if (i == ARRAY_SIZE(torture_ops)) {
1113	printk(KERN_ALERT "rcutorture: invalid torture type: \"%s\"\n",
1114	torture_type);
1115	mutex_unlock(&fullstop_mutex);
1116	return -EINVAL;
1117	}
1118	if (cur_ops->init)
1119	cur_ops->init(); /* no "goto unwind" prior to this point!!! */
1120
1121	if (nreaders >= 0)
1122	nrealreaders = nreaders;
1123	else
1124	nrealreaders = 2 * num_online_cpus();
1125	rcu_torture_print_module_parms("Start of test");
1126	fullstop = FULLSTOP_DONTSTOP;
1127
1128	/* Set up the freelist. */
1129
1130	INIT_LIST_HEAD(&rcu_torture_freelist);
1131	for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1132	rcu_tortures[i].rtort_mbtest = 0;
1133	list_add_tail(&rcu_tortures[i].rtort_free,
1134	&rcu_torture_freelist);
1135	}
1136
1137	/* Initialize the statistics so that each run gets its own numbers. */
1138
1139	rcu_torture_current = NULL;
1140	rcu_torture_current_version = 0;
1141	atomic_set(&n_rcu_torture_alloc, 0);
1142	atomic_set(&n_rcu_torture_alloc_fail, 0);
1143	atomic_set(&n_rcu_torture_free, 0);
1144	atomic_set(&n_rcu_torture_mberror, 0);
1145	atomic_set(&n_rcu_torture_error, 0);
1146	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1147	atomic_set(&rcu_torture_wcount[i], 0);
1148	for_each_possible_cpu(cpu) {
1149	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1150	per_cpu(rcu_torture_count, cpu)[i] = 0;
1151	per_cpu(rcu_torture_batch, cpu)[i] = 0;
1152	}
1153	}
1154
1155	/* Start up the kthreads. */
1156
1157	VERBOSE_PRINTK_STRING("Creating rcu_torture_writer task");
1158	writer_task = kthread_run(rcu_torture_writer, NULL,
1159	"rcu_torture_writer");
1160	if (IS_ERR(writer_task)) {
1161	firsterr = PTR_ERR(writer_task);
1162	VERBOSE_PRINTK_ERRSTRING("Failed to create writer");
1163	writer_task = NULL;
1164	goto unwind;
1165	}
1166	fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]),
1167	GFP_KERNEL);
1168	if (fakewriter_tasks == NULL) {
1169	VERBOSE_PRINTK_ERRSTRING("out of memory");
1170	firsterr = -ENOMEM;
1171	goto unwind;
1172	}
1173	for (i = 0; i < nfakewriters; i++) {
1174	VERBOSE_PRINTK_STRING("Creating rcu_torture_fakewriter task");
1175	fakewriter_tasks[i] = kthread_run(rcu_torture_fakewriter, NULL,
1176	"rcu_torture_fakewriter");
1177	if (IS_ERR(fakewriter_tasks[i])) {
1178	firsterr = PTR_ERR(fakewriter_tasks[i]);
1179	VERBOSE_PRINTK_ERRSTRING("Failed to create fakewriter");
1180	fakewriter_tasks[i] = NULL;
1181	goto unwind;
1182	}
1183	}
1184	reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
1185	GFP_KERNEL);
1186	if (reader_tasks == NULL) {
1187	VERBOSE_PRINTK_ERRSTRING("out of memory");
1188	firsterr = -ENOMEM;
1189	goto unwind;
1190	}
1191	for (i = 0; i < nrealreaders; i++) {
1192	VERBOSE_PRINTK_STRING("Creating rcu_torture_reader task");
1193	reader_tasks[i] = kthread_run(rcu_torture_reader, NULL,
1194	"rcu_torture_reader");
1195	if (IS_ERR(reader_tasks[i])) {
1196	firsterr = PTR_ERR(reader_tasks[i]);
1197	VERBOSE_PRINTK_ERRSTRING("Failed to create reader");
1198	reader_tasks[i] = NULL;
1199	goto unwind;
1200	}
1201	}
1202	if (stat_interval > 0) {
1203	VERBOSE_PRINTK_STRING("Creating rcu_torture_stats task");
1204	stats_task = kthread_run(rcu_torture_stats, NULL,
1205	"rcu_torture_stats");
1206	if (IS_ERR(stats_task)) {
1207	firsterr = PTR_ERR(stats_task);
1208	VERBOSE_PRINTK_ERRSTRING("Failed to create stats");
1209	stats_task = NULL;
1210	goto unwind;
1211	}
1212	}
1213	if (test_no_idle_hz) {
1214	rcu_idle_cpu = num_online_cpus() - 1;
1215
1216	if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
1217	firsterr = -ENOMEM;
1218	VERBOSE_PRINTK_ERRSTRING("Failed to alloc mask");
1219	goto unwind;
1220	}
1221
1222	/* Create the shuffler thread */
1223	shuffler_task = kthread_run(rcu_torture_shuffle, NULL,
1224	"rcu_torture_shuffle");
1225	if (IS_ERR(shuffler_task)) {
1226	free_cpumask_var(shuffle_tmp_mask);
1227	firsterr = PTR_ERR(shuffler_task);
1228	VERBOSE_PRINTK_ERRSTRING("Failed to create shuffler");
1229	shuffler_task = NULL;
1230	goto unwind;
1231	}
1232	}
1233	if (stutter < 0)
1234	stutter = 0;
1235	if (stutter) {
1236	/* Create the stutter thread */
1237	stutter_task = kthread_run(rcu_torture_stutter, NULL,
1238	"rcu_torture_stutter");
1239	if (IS_ERR(stutter_task)) {
1240	firsterr = PTR_ERR(stutter_task);
1241	VERBOSE_PRINTK_ERRSTRING("Failed to create stutter");
1242	stutter_task = NULL;
1243	goto unwind;
1244	}
1245	}
1246	register_reboot_notifier(&rcutorture_nb);
1247	mutex_unlock(&fullstop_mutex);
1248	return 0;
1249
1250	unwind:
1251	mutex_unlock(&fullstop_mutex);
1252	rcu_torture_cleanup();
1253	return firsterr;
1254	}
1255
1256	module_init(rcu_torture_init);
1257	module_exit(rcu_torture_cleanup);
1258

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