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a241ec65 PM |
1 | /* |
2 | * Read-Copy Update /proc-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 | |
19 | * | |
20 | * Authors: Paul E. McKenney <paulmck@us.ibm.com> | |
21 | * | |
22 | * See also: Documentation/RCU/torture.txt | |
23 | */ | |
24 | #include <linux/types.h> | |
25 | #include <linux/kernel.h> | |
26 | #include <linux/init.h> | |
27 | #include <linux/module.h> | |
28 | #include <linux/kthread.h> | |
29 | #include <linux/err.h> | |
30 | #include <linux/spinlock.h> | |
31 | #include <linux/smp.h> | |
32 | #include <linux/rcupdate.h> | |
33 | #include <linux/interrupt.h> | |
34 | #include <linux/sched.h> | |
35 | #include <asm/atomic.h> | |
36 | #include <linux/bitops.h> | |
37 | #include <linux/module.h> | |
38 | #include <linux/completion.h> | |
39 | #include <linux/moduleparam.h> | |
40 | #include <linux/percpu.h> | |
41 | #include <linux/notifier.h> | |
a241ec65 PM |
42 | #include <linux/cpu.h> |
43 | #include <linux/random.h> | |
44 | #include <linux/delay.h> | |
45 | #include <linux/byteorder/swabb.h> | |
46 | #include <linux/stat.h> | |
47 | ||
48 | MODULE_LICENSE("GPL"); | |
49 | ||
50 | static int nreaders = -1; /* # reader threads, defaults to 4*ncpus */ | |
51 | static int stat_interval = 0; /* Interval between stats, in seconds. */ | |
52 | /* Defaults to "only at end of test". */ | |
53 | static int verbose = 0; /* Print more debug info. */ | |
54 | ||
55 | MODULE_PARM(nreaders, "i"); | |
56 | MODULE_PARM_DESC(nreaders, "Number of RCU reader threads"); | |
57 | MODULE_PARM(stat_interval, "i"); | |
58 | MODULE_PARM_DESC(stat_interval, "Number of seconds between stats printk()s"); | |
59 | MODULE_PARM(verbose, "i"); | |
60 | MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s"); | |
61 | #define TORTURE_FLAG "rcutorture: " | |
62 | #define PRINTK_STRING(s) \ | |
63 | do { printk(KERN_ALERT TORTURE_FLAG s "\n"); } while (0) | |
64 | #define VERBOSE_PRINTK_STRING(s) \ | |
65 | do { if (verbose) printk(KERN_ALERT TORTURE_FLAG s "\n"); } while (0) | |
66 | #define VERBOSE_PRINTK_ERRSTRING(s) \ | |
67 | do { if (verbose) printk(KERN_ALERT TORTURE_FLAG "!!! " s "\n"); } while (0) | |
68 | ||
69 | static char printk_buf[4096]; | |
70 | ||
71 | static int nrealreaders; | |
72 | static struct task_struct *writer_task; | |
73 | static struct task_struct **reader_tasks; | |
74 | static struct task_struct *stats_task; | |
75 | ||
76 | #define RCU_TORTURE_PIPE_LEN 10 | |
77 | ||
78 | struct rcu_torture { | |
79 | struct rcu_head rtort_rcu; | |
80 | int rtort_pipe_count; | |
81 | struct list_head rtort_free; | |
996417d2 | 82 | int rtort_mbtest; |
a241ec65 PM |
83 | }; |
84 | ||
85 | static int fullstop = 0; /* stop generating callbacks at test end. */ | |
86 | static LIST_HEAD(rcu_torture_freelist); | |
87 | static struct rcu_torture *rcu_torture_current = NULL; | |
88 | static long rcu_torture_current_version = 0; | |
89 | static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN]; | |
90 | static DEFINE_SPINLOCK(rcu_torture_lock); | |
91 | static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) = | |
92 | { 0 }; | |
93 | static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) = | |
94 | { 0 }; | |
95 | static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1]; | |
96 | atomic_t n_rcu_torture_alloc; | |
97 | atomic_t n_rcu_torture_alloc_fail; | |
98 | atomic_t n_rcu_torture_free; | |
996417d2 PM |
99 | atomic_t n_rcu_torture_mberror; |
100 | atomic_t n_rcu_torture_error; | |
a241ec65 PM |
101 | |
102 | /* | |
103 | * Allocate an element from the rcu_tortures pool. | |
104 | */ | |
97a41e26 | 105 | static struct rcu_torture * |
a241ec65 PM |
106 | rcu_torture_alloc(void) |
107 | { | |
108 | struct list_head *p; | |
109 | ||
110 | spin_lock(&rcu_torture_lock); | |
111 | if (list_empty(&rcu_torture_freelist)) { | |
112 | atomic_inc(&n_rcu_torture_alloc_fail); | |
113 | spin_unlock(&rcu_torture_lock); | |
114 | return NULL; | |
115 | } | |
116 | atomic_inc(&n_rcu_torture_alloc); | |
117 | p = rcu_torture_freelist.next; | |
118 | list_del_init(p); | |
119 | spin_unlock(&rcu_torture_lock); | |
120 | return container_of(p, struct rcu_torture, rtort_free); | |
121 | } | |
122 | ||
123 | /* | |
124 | * Free an element to the rcu_tortures pool. | |
125 | */ | |
126 | static void | |
127 | rcu_torture_free(struct rcu_torture *p) | |
128 | { | |
129 | atomic_inc(&n_rcu_torture_free); | |
130 | spin_lock(&rcu_torture_lock); | |
131 | list_add_tail(&p->rtort_free, &rcu_torture_freelist); | |
132 | spin_unlock(&rcu_torture_lock); | |
133 | } | |
134 | ||
135 | static void | |
136 | rcu_torture_cb(struct rcu_head *p) | |
137 | { | |
138 | int i; | |
139 | struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu); | |
140 | ||
141 | if (fullstop) { | |
142 | /* Test is ending, just drop callbacks on the floor. */ | |
143 | /* The next initialization will pick up the pieces. */ | |
144 | return; | |
145 | } | |
146 | i = rp->rtort_pipe_count; | |
147 | if (i > RCU_TORTURE_PIPE_LEN) | |
148 | i = RCU_TORTURE_PIPE_LEN; | |
149 | atomic_inc(&rcu_torture_wcount[i]); | |
996417d2 PM |
150 | if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) { |
151 | rp->rtort_mbtest = 0; | |
a241ec65 | 152 | rcu_torture_free(rp); |
996417d2 | 153 | } else |
a241ec65 PM |
154 | call_rcu(p, rcu_torture_cb); |
155 | } | |
156 | ||
157 | struct rcu_random_state { | |
158 | unsigned long rrs_state; | |
159 | unsigned long rrs_count; | |
160 | }; | |
161 | ||
162 | #define RCU_RANDOM_MULT 39916801 /* prime */ | |
163 | #define RCU_RANDOM_ADD 479001701 /* prime */ | |
164 | #define RCU_RANDOM_REFRESH 10000 | |
165 | ||
166 | #define DEFINE_RCU_RANDOM(name) struct rcu_random_state name = { 0, 0 } | |
167 | ||
168 | /* | |
169 | * Crude but fast random-number generator. Uses a linear congruential | |
170 | * generator, with occasional help from get_random_bytes(). | |
171 | */ | |
172 | static long | |
173 | rcu_random(struct rcu_random_state *rrsp) | |
174 | { | |
175 | long refresh; | |
176 | ||
177 | if (--rrsp->rrs_count < 0) { | |
178 | get_random_bytes(&refresh, sizeof(refresh)); | |
179 | rrsp->rrs_state += refresh; | |
180 | rrsp->rrs_count = RCU_RANDOM_REFRESH; | |
181 | } | |
182 | rrsp->rrs_state = rrsp->rrs_state * RCU_RANDOM_MULT + RCU_RANDOM_ADD; | |
183 | return swahw32(rrsp->rrs_state); | |
184 | } | |
185 | ||
186 | /* | |
187 | * RCU torture writer kthread. Repeatedly substitutes a new structure | |
188 | * for that pointed to by rcu_torture_current, freeing the old structure | |
189 | * after a series of grace periods (the "pipeline"). | |
190 | */ | |
191 | static int | |
192 | rcu_torture_writer(void *arg) | |
193 | { | |
194 | int i; | |
195 | long oldbatch = rcu_batches_completed(); | |
196 | struct rcu_torture *rp; | |
197 | struct rcu_torture *old_rp; | |
198 | static DEFINE_RCU_RANDOM(rand); | |
199 | ||
200 | VERBOSE_PRINTK_STRING("rcu_torture_writer task started"); | |
dbdf65b1 IM |
201 | set_user_nice(current, 19); |
202 | ||
a241ec65 PM |
203 | do { |
204 | schedule_timeout_uninterruptible(1); | |
205 | if (rcu_batches_completed() == oldbatch) | |
206 | continue; | |
207 | if ((rp = rcu_torture_alloc()) == NULL) | |
208 | continue; | |
209 | rp->rtort_pipe_count = 0; | |
210 | udelay(rcu_random(&rand) & 0x3ff); | |
211 | old_rp = rcu_torture_current; | |
996417d2 | 212 | rp->rtort_mbtest = 1; |
a241ec65 PM |
213 | rcu_assign_pointer(rcu_torture_current, rp); |
214 | smp_wmb(); | |
215 | if (old_rp != NULL) { | |
216 | i = old_rp->rtort_pipe_count; | |
217 | if (i > RCU_TORTURE_PIPE_LEN) | |
218 | i = RCU_TORTURE_PIPE_LEN; | |
219 | atomic_inc(&rcu_torture_wcount[i]); | |
220 | old_rp->rtort_pipe_count++; | |
221 | call_rcu(&old_rp->rtort_rcu, rcu_torture_cb); | |
222 | } | |
223 | rcu_torture_current_version++; | |
224 | oldbatch = rcu_batches_completed(); | |
225 | } while (!kthread_should_stop() && !fullstop); | |
226 | VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping"); | |
227 | while (!kthread_should_stop()) | |
228 | schedule_timeout_uninterruptible(1); | |
229 | return 0; | |
230 | } | |
231 | ||
232 | /* | |
233 | * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current, | |
234 | * incrementing the corresponding element of the pipeline array. The | |
235 | * counter in the element should never be greater than 1, otherwise, the | |
236 | * RCU implementation is broken. | |
237 | */ | |
238 | static int | |
239 | rcu_torture_reader(void *arg) | |
240 | { | |
241 | int completed; | |
242 | DEFINE_RCU_RANDOM(rand); | |
243 | struct rcu_torture *p; | |
244 | int pipe_count; | |
245 | ||
246 | VERBOSE_PRINTK_STRING("rcu_torture_reader task started"); | |
dbdf65b1 IM |
247 | set_user_nice(current, 19); |
248 | ||
a241ec65 PM |
249 | do { |
250 | rcu_read_lock(); | |
251 | completed = rcu_batches_completed(); | |
252 | p = rcu_dereference(rcu_torture_current); | |
253 | if (p == NULL) { | |
254 | /* Wait for rcu_torture_writer to get underway */ | |
255 | rcu_read_unlock(); | |
256 | schedule_timeout_interruptible(HZ); | |
257 | continue; | |
258 | } | |
996417d2 PM |
259 | if (p->rtort_mbtest == 0) |
260 | atomic_inc(&n_rcu_torture_mberror); | |
a241ec65 PM |
261 | udelay(rcu_random(&rand) & 0x7f); |
262 | preempt_disable(); | |
263 | pipe_count = p->rtort_pipe_count; | |
264 | if (pipe_count > RCU_TORTURE_PIPE_LEN) { | |
265 | /* Should not happen, but... */ | |
266 | pipe_count = RCU_TORTURE_PIPE_LEN; | |
267 | } | |
268 | ++__get_cpu_var(rcu_torture_count)[pipe_count]; | |
269 | completed = rcu_batches_completed() - completed; | |
270 | if (completed > RCU_TORTURE_PIPE_LEN) { | |
271 | /* Should not happen, but... */ | |
272 | completed = RCU_TORTURE_PIPE_LEN; | |
273 | } | |
274 | ++__get_cpu_var(rcu_torture_batch)[completed]; | |
275 | preempt_enable(); | |
276 | rcu_read_unlock(); | |
277 | schedule(); | |
278 | } while (!kthread_should_stop() && !fullstop); | |
279 | VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping"); | |
280 | while (!kthread_should_stop()) | |
281 | schedule_timeout_uninterruptible(1); | |
282 | return 0; | |
283 | } | |
284 | ||
285 | /* | |
286 | * Create an RCU-torture statistics message in the specified buffer. | |
287 | */ | |
288 | static int | |
289 | rcu_torture_printk(char *page) | |
290 | { | |
291 | int cnt = 0; | |
292 | int cpu; | |
293 | int i; | |
294 | long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; | |
295 | long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; | |
296 | ||
297 | for_each_cpu(cpu) { | |
298 | for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { | |
299 | pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i]; | |
300 | batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i]; | |
301 | } | |
302 | } | |
303 | for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) { | |
304 | if (pipesummary[i] != 0) | |
305 | break; | |
306 | } | |
307 | cnt += sprintf(&page[cnt], "rcutorture: "); | |
308 | cnt += sprintf(&page[cnt], | |
996417d2 PM |
309 | "rtc: %p ver: %ld tfle: %d rta: %d rtaf: %d rtf: %d " |
310 | "rtmbe: %d", | |
a241ec65 PM |
311 | rcu_torture_current, |
312 | rcu_torture_current_version, | |
313 | list_empty(&rcu_torture_freelist), | |
314 | atomic_read(&n_rcu_torture_alloc), | |
315 | atomic_read(&n_rcu_torture_alloc_fail), | |
996417d2 PM |
316 | atomic_read(&n_rcu_torture_free), |
317 | atomic_read(&n_rcu_torture_mberror)); | |
318 | if (atomic_read(&n_rcu_torture_mberror) != 0) | |
319 | cnt += sprintf(&page[cnt], " !!!"); | |
a241ec65 | 320 | cnt += sprintf(&page[cnt], "\nrcutorture: "); |
996417d2 | 321 | if (i > 1) { |
a241ec65 | 322 | cnt += sprintf(&page[cnt], "!!! "); |
996417d2 PM |
323 | atomic_inc(&n_rcu_torture_error); |
324 | } | |
a241ec65 PM |
325 | cnt += sprintf(&page[cnt], "Reader Pipe: "); |
326 | for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) | |
327 | cnt += sprintf(&page[cnt], " %ld", pipesummary[i]); | |
328 | cnt += sprintf(&page[cnt], "\nrcutorture: "); | |
329 | cnt += sprintf(&page[cnt], "Reader Batch: "); | |
330 | for (i = 0; i < RCU_TORTURE_PIPE_LEN; i++) | |
331 | cnt += sprintf(&page[cnt], " %ld", batchsummary[i]); | |
332 | cnt += sprintf(&page[cnt], "\nrcutorture: "); | |
333 | cnt += sprintf(&page[cnt], "Free-Block Circulation: "); | |
334 | for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { | |
335 | cnt += sprintf(&page[cnt], " %d", | |
336 | atomic_read(&rcu_torture_wcount[i])); | |
337 | } | |
338 | cnt += sprintf(&page[cnt], "\n"); | |
339 | return cnt; | |
340 | } | |
341 | ||
342 | /* | |
343 | * Print torture statistics. Caller must ensure that there is only | |
344 | * one call to this function at a given time!!! This is normally | |
345 | * accomplished by relying on the module system to only have one copy | |
346 | * of the module loaded, and then by giving the rcu_torture_stats | |
347 | * kthread full control (or the init/cleanup functions when rcu_torture_stats | |
348 | * thread is not running). | |
349 | */ | |
350 | static void | |
351 | rcu_torture_stats_print(void) | |
352 | { | |
353 | int cnt; | |
354 | ||
355 | cnt = rcu_torture_printk(printk_buf); | |
356 | printk(KERN_ALERT "%s", printk_buf); | |
357 | } | |
358 | ||
359 | /* | |
360 | * Periodically prints torture statistics, if periodic statistics printing | |
361 | * was specified via the stat_interval module parameter. | |
362 | * | |
363 | * No need to worry about fullstop here, since this one doesn't reference | |
364 | * volatile state or register callbacks. | |
365 | */ | |
366 | static int | |
367 | rcu_torture_stats(void *arg) | |
368 | { | |
369 | VERBOSE_PRINTK_STRING("rcu_torture_stats task started"); | |
370 | do { | |
371 | schedule_timeout_interruptible(stat_interval * HZ); | |
372 | rcu_torture_stats_print(); | |
373 | } while (!kthread_should_stop()); | |
374 | VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping"); | |
375 | return 0; | |
376 | } | |
377 | ||
378 | static void | |
379 | rcu_torture_cleanup(void) | |
380 | { | |
381 | int i; | |
382 | ||
383 | fullstop = 1; | |
384 | if (writer_task != NULL) { | |
385 | VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task"); | |
386 | kthread_stop(writer_task); | |
387 | } | |
388 | writer_task = NULL; | |
389 | ||
390 | if (reader_tasks != NULL) { | |
391 | for (i = 0; i < nrealreaders; i++) { | |
392 | if (reader_tasks[i] != NULL) { | |
393 | VERBOSE_PRINTK_STRING( | |
394 | "Stopping rcu_torture_reader task"); | |
395 | kthread_stop(reader_tasks[i]); | |
396 | } | |
397 | reader_tasks[i] = NULL; | |
398 | } | |
399 | kfree(reader_tasks); | |
400 | reader_tasks = NULL; | |
401 | } | |
402 | rcu_torture_current = NULL; | |
403 | ||
404 | if (stats_task != NULL) { | |
405 | VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task"); | |
406 | kthread_stop(stats_task); | |
407 | } | |
408 | stats_task = NULL; | |
409 | ||
410 | /* Wait for all RCU callbacks to fire. */ | |
89d46b87 | 411 | rcu_barrier(); |
a241ec65 | 412 | |
a241ec65 | 413 | rcu_torture_stats_print(); /* -After- the stats thread is stopped! */ |
996417d2 PM |
414 | printk(KERN_ALERT TORTURE_FLAG |
415 | "--- End of test: %s\n", | |
416 | atomic_read(&n_rcu_torture_error) == 0 ? "SUCCESS" : "FAILURE"); | |
a241ec65 PM |
417 | } |
418 | ||
419 | static int | |
420 | rcu_torture_init(void) | |
421 | { | |
422 | int i; | |
423 | int cpu; | |
424 | int firsterr = 0; | |
425 | ||
426 | /* Process args and tell the world that the torturer is on the job. */ | |
427 | ||
428 | if (nreaders >= 0) | |
429 | nrealreaders = nreaders; | |
430 | else | |
431 | nrealreaders = 2 * num_online_cpus(); | |
432 | printk(KERN_ALERT TORTURE_FLAG | |
433 | "--- Start of test: nreaders=%d stat_interval=%d verbose=%d\n", | |
434 | nrealreaders, stat_interval, verbose); | |
435 | fullstop = 0; | |
436 | ||
437 | /* Set up the freelist. */ | |
438 | ||
439 | INIT_LIST_HEAD(&rcu_torture_freelist); | |
440 | for (i = 0; i < sizeof(rcu_tortures) / sizeof(rcu_tortures[0]); i++) { | |
996417d2 | 441 | rcu_tortures[i].rtort_mbtest = 0; |
a241ec65 PM |
442 | list_add_tail(&rcu_tortures[i].rtort_free, |
443 | &rcu_torture_freelist); | |
444 | } | |
445 | ||
446 | /* Initialize the statistics so that each run gets its own numbers. */ | |
447 | ||
448 | rcu_torture_current = NULL; | |
449 | rcu_torture_current_version = 0; | |
450 | atomic_set(&n_rcu_torture_alloc, 0); | |
451 | atomic_set(&n_rcu_torture_alloc_fail, 0); | |
452 | atomic_set(&n_rcu_torture_free, 0); | |
996417d2 PM |
453 | atomic_set(&n_rcu_torture_mberror, 0); |
454 | atomic_set(&n_rcu_torture_error, 0); | |
a241ec65 PM |
455 | for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) |
456 | atomic_set(&rcu_torture_wcount[i], 0); | |
457 | for_each_cpu(cpu) { | |
458 | for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { | |
459 | per_cpu(rcu_torture_count, cpu)[i] = 0; | |
460 | per_cpu(rcu_torture_batch, cpu)[i] = 0; | |
461 | } | |
462 | } | |
463 | ||
464 | /* Start up the kthreads. */ | |
465 | ||
466 | VERBOSE_PRINTK_STRING("Creating rcu_torture_writer task"); | |
467 | writer_task = kthread_run(rcu_torture_writer, NULL, | |
468 | "rcu_torture_writer"); | |
469 | if (IS_ERR(writer_task)) { | |
470 | firsterr = PTR_ERR(writer_task); | |
471 | VERBOSE_PRINTK_ERRSTRING("Failed to create writer"); | |
472 | writer_task = NULL; | |
473 | goto unwind; | |
474 | } | |
475 | reader_tasks = kmalloc(nrealreaders * sizeof(reader_tasks[0]), | |
476 | GFP_KERNEL); | |
477 | if (reader_tasks == NULL) { | |
478 | VERBOSE_PRINTK_ERRSTRING("out of memory"); | |
479 | firsterr = -ENOMEM; | |
480 | goto unwind; | |
481 | } | |
482 | for (i = 0; i < nrealreaders; i++) { | |
483 | VERBOSE_PRINTK_STRING("Creating rcu_torture_reader task"); | |
484 | reader_tasks[i] = kthread_run(rcu_torture_reader, NULL, | |
485 | "rcu_torture_reader"); | |
486 | if (IS_ERR(reader_tasks[i])) { | |
487 | firsterr = PTR_ERR(reader_tasks[i]); | |
488 | VERBOSE_PRINTK_ERRSTRING("Failed to create reader"); | |
489 | reader_tasks[i] = NULL; | |
490 | goto unwind; | |
491 | } | |
492 | } | |
493 | if (stat_interval > 0) { | |
494 | VERBOSE_PRINTK_STRING("Creating rcu_torture_stats task"); | |
495 | stats_task = kthread_run(rcu_torture_stats, NULL, | |
496 | "rcu_torture_stats"); | |
497 | if (IS_ERR(stats_task)) { | |
498 | firsterr = PTR_ERR(stats_task); | |
499 | VERBOSE_PRINTK_ERRSTRING("Failed to create stats"); | |
500 | stats_task = NULL; | |
501 | goto unwind; | |
502 | } | |
503 | } | |
504 | return 0; | |
505 | ||
506 | unwind: | |
507 | rcu_torture_cleanup(); | |
508 | return firsterr; | |
509 | } | |
510 | ||
511 | module_init(rcu_torture_init); | |
512 | module_exit(rcu_torture_cleanup); |