Linux 3.15-rc1
[deliverable/linux.git] / kernel / rcu / rcutorture.c
CommitLineData
a241ec65 1/*
29766f1e 2 * Read-Copy Update module-based torture test facility
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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
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15 * along with this program; if not, you can access it online at
16 * http://www.gnu.org/licenses/gpl-2.0.html.
a241ec65 17 *
b772e1dd 18 * Copyright (C) IBM Corporation, 2005, 2006
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19 *
20 * Authors: Paul E. McKenney <paulmck@us.ibm.com>
a71fca58 21 * Josh Triplett <josh@freedesktop.org>
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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>
60063497 36#include <linux/atomic.h>
a241ec65 37#include <linux/bitops.h>
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38#include <linux/completion.h>
39#include <linux/moduleparam.h>
40#include <linux/percpu.h>
41#include <linux/notifier.h>
343e9099 42#include <linux/reboot.h>
83144186 43#include <linux/freezer.h>
a241ec65 44#include <linux/cpu.h>
a241ec65 45#include <linux/delay.h>
a241ec65 46#include <linux/stat.h>
b2896d2e 47#include <linux/srcu.h>
1aeb272c 48#include <linux/slab.h>
52494535 49#include <linux/trace_clock.h>
f07767fd 50#include <asm/byteorder.h>
51b1130e 51#include <linux/torture.h>
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52
53MODULE_LICENSE("GPL");
5cf05ad7 54MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@freedesktop.org>");
a241ec65 55
4102adab 56
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57torture_param(int, fqs_duration, 0,
58 "Duration of fqs bursts (us), 0 to disable");
59torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
60torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
61torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
62torture_param(bool, gp_normal, false,
63 "Use normal (non-expedited) GP wait primitives");
64torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
65torture_param(int, n_barrier_cbs, 0,
66 "# of callbacks/kthreads for barrier testing");
67torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
68torture_param(int, nreaders, -1, "Number of RCU reader threads");
69torture_param(int, object_debug, 0,
70 "Enable debug-object double call_rcu() testing");
71torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
72torture_param(int, onoff_interval, 0,
73 "Time between CPU hotplugs (s), 0=disable");
74torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
75torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
76torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
77torture_param(int, stall_cpu_holdoff, 10,
78 "Time to wait before starting stall (s).");
79torture_param(int, stat_interval, 60,
80 "Number of seconds between stats printk()s");
81torture_param(int, stutter, 5, "Number of seconds to run/halt test");
82torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
83torture_param(int, test_boost_duration, 4,
84 "Duration of each boost test, seconds.");
85torture_param(int, test_boost_interval, 7,
86 "Interval between boost tests, seconds.");
87torture_param(bool, test_no_idle_hz, true,
88 "Test support for tickless idle CPUs");
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89torture_param(bool, verbose, true,
90 "Enable verbose debugging printk()s");
9e250225 91
d10453e9 92static char *torture_type = "rcu";
d6ad6711 93module_param(torture_type, charp, 0444);
d10453e9 94MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, ...)");
a241ec65 95
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96static int nrealreaders;
97static struct task_struct *writer_task;
b772e1dd 98static struct task_struct **fakewriter_tasks;
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99static struct task_struct **reader_tasks;
100static struct task_struct *stats_task;
bf66f18e 101static struct task_struct *fqs_task;
8e8be45e 102static struct task_struct *boost_tasks[NR_CPUS];
c13f3757 103static struct task_struct *stall_task;
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104static struct task_struct **barrier_cbs_tasks;
105static struct task_struct *barrier_task;
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106
107#define RCU_TORTURE_PIPE_LEN 10
108
109struct rcu_torture {
110 struct rcu_head rtort_rcu;
111 int rtort_pipe_count;
112 struct list_head rtort_free;
996417d2 113 int rtort_mbtest;
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114};
115
a241ec65 116static LIST_HEAD(rcu_torture_freelist);
0ddea0ea 117static struct rcu_torture __rcu *rcu_torture_current;
4a298656 118static unsigned long rcu_torture_current_version;
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119static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
120static DEFINE_SPINLOCK(rcu_torture_lock);
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121static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1],
122 rcu_torture_count) = { 0 };
123static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1],
124 rcu_torture_batch) = { 0 };
a241ec65 125static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
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126static atomic_t n_rcu_torture_alloc;
127static atomic_t n_rcu_torture_alloc_fail;
128static atomic_t n_rcu_torture_free;
129static atomic_t n_rcu_torture_mberror;
130static atomic_t n_rcu_torture_error;
fae4b54f 131static long n_rcu_torture_barrier_error;
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132static long n_rcu_torture_boost_ktrerror;
133static long n_rcu_torture_boost_rterror;
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134static long n_rcu_torture_boost_failure;
135static long n_rcu_torture_boosts;
a71fca58 136static long n_rcu_torture_timers;
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137static long n_barrier_attempts;
138static long n_barrier_successes;
e3033736 139static struct list_head rcu_torture_removed;
d120f65f 140
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141#if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
142#define RCUTORTURE_RUNNABLE_INIT 1
143#else
144#define RCUTORTURE_RUNNABLE_INIT 0
145#endif
146int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT;
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147module_param(rcutorture_runnable, int, 0444);
148MODULE_PARM_DESC(rcutorture_runnable, "Start rcutorture at boot");
31a72bce 149
3acf4a9a 150#if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
8e8be45e 151#define rcu_can_boost() 1
3acf4a9a 152#else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
8e8be45e 153#define rcu_can_boost() 0
3acf4a9a 154#endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
8e8be45e 155
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156#ifdef CONFIG_RCU_TRACE
157static u64 notrace rcu_trace_clock_local(void)
158{
159 u64 ts = trace_clock_local();
160 unsigned long __maybe_unused ts_rem = do_div(ts, NSEC_PER_USEC);
161 return ts;
162}
163#else /* #ifdef CONFIG_RCU_TRACE */
164static u64 notrace rcu_trace_clock_local(void)
165{
166 return 0ULL;
167}
168#endif /* #else #ifdef CONFIG_RCU_TRACE */
169
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170static unsigned long boost_starttime; /* jiffies of next boost test start. */
171DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
172 /* and boost task create/destroy. */
fae4b54f 173static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
c6ebcbb6 174static bool barrier_phase; /* Test phase. */
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175static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
176static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
177static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
8e8be45e 178
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179/*
180 * Allocate an element from the rcu_tortures pool.
181 */
97a41e26 182static struct rcu_torture *
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183rcu_torture_alloc(void)
184{
185 struct list_head *p;
186
adac1665 187 spin_lock_bh(&rcu_torture_lock);
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188 if (list_empty(&rcu_torture_freelist)) {
189 atomic_inc(&n_rcu_torture_alloc_fail);
adac1665 190 spin_unlock_bh(&rcu_torture_lock);
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191 return NULL;
192 }
193 atomic_inc(&n_rcu_torture_alloc);
194 p = rcu_torture_freelist.next;
195 list_del_init(p);
adac1665 196 spin_unlock_bh(&rcu_torture_lock);
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197 return container_of(p, struct rcu_torture, rtort_free);
198}
199
200/*
201 * Free an element to the rcu_tortures pool.
202 */
203static void
204rcu_torture_free(struct rcu_torture *p)
205{
206 atomic_inc(&n_rcu_torture_free);
adac1665 207 spin_lock_bh(&rcu_torture_lock);
a241ec65 208 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
adac1665 209 spin_unlock_bh(&rcu_torture_lock);
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210}
211
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212/*
213 * Operations vector for selecting different types of tests.
214 */
215
216struct rcu_torture_ops {
217 void (*init)(void);
72e9bb54 218 int (*readlock)(void);
51b1130e 219 void (*read_delay)(struct torture_random_state *rrsp);
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220 void (*readunlock)(int idx);
221 int (*completed)(void);
0acc512c 222 void (*deferred_free)(struct rcu_torture *p);
b772e1dd 223 void (*sync)(void);
2ec1f2d9 224 void (*exp_sync)(void);
fae4b54f 225 void (*call)(struct rcu_head *head, void (*func)(struct rcu_head *rcu));
2326974d 226 void (*cb_barrier)(void);
bf66f18e 227 void (*fqs)(void);
d1008950 228 void (*stats)(char *page);
0acc512c 229 int irq_capable;
8e8be45e 230 int can_boost;
e66c33d5 231 const char *name;
72e9bb54 232};
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233
234static struct rcu_torture_ops *cur_ops;
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235
236/*
237 * Definitions for rcu torture testing.
238 */
239
a49a4af7 240static int rcu_torture_read_lock(void) __acquires(RCU)
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241{
242 rcu_read_lock();
243 return 0;
244}
245
51b1130e 246static void rcu_read_delay(struct torture_random_state *rrsp)
b2896d2e 247{
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248 const unsigned long shortdelay_us = 200;
249 const unsigned long longdelay_ms = 50;
b2896d2e 250
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251 /* We want a short delay sometimes to make a reader delay the grace
252 * period, and we want a long delay occasionally to trigger
253 * force_quiescent_state. */
b2896d2e 254
51b1130e 255 if (!(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms)))
b8d57a76 256 mdelay(longdelay_ms);
51b1130e 257 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
b8d57a76 258 udelay(shortdelay_us);
e546f485 259#ifdef CONFIG_PREEMPT
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260 if (!preempt_count() &&
261 !(torture_random(rrsp) % (nrealreaders * 20000)))
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262 preempt_schedule(); /* No QS if preempt_disable() in effect */
263#endif
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264}
265
a49a4af7 266static void rcu_torture_read_unlock(int idx) __releases(RCU)
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267{
268 rcu_read_unlock();
269}
270
271static int rcu_torture_completed(void)
272{
273 return rcu_batches_completed();
274}
275
276static void
277rcu_torture_cb(struct rcu_head *p)
278{
279 int i;
280 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
281
36970bb9 282 if (torture_must_stop_irq()) {
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283 /* Test is ending, just drop callbacks on the floor. */
284 /* The next initialization will pick up the pieces. */
285 return;
286 }
287 i = rp->rtort_pipe_count;
288 if (i > RCU_TORTURE_PIPE_LEN)
289 i = RCU_TORTURE_PIPE_LEN;
290 atomic_inc(&rcu_torture_wcount[i]);
291 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
292 rp->rtort_mbtest = 0;
293 rcu_torture_free(rp);
c701d5d9 294 } else {
0acc512c 295 cur_ops->deferred_free(rp);
c701d5d9 296 }
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297}
298
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299static int rcu_no_completed(void)
300{
301 return 0;
302}
303
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304static void rcu_torture_deferred_free(struct rcu_torture *p)
305{
306 call_rcu(&p->rtort_rcu, rcu_torture_cb);
307}
308
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309static void rcu_sync_torture_init(void)
310{
311 INIT_LIST_HEAD(&rcu_torture_removed);
312}
313
2ec1f2d9 314static struct rcu_torture_ops rcu_ops = {
0acc512c 315 .init = rcu_sync_torture_init,
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316 .readlock = rcu_torture_read_lock,
317 .read_delay = rcu_read_delay,
318 .readunlock = rcu_torture_read_unlock,
319 .completed = rcu_torture_completed,
2ec1f2d9 320 .deferred_free = rcu_torture_deferred_free,
0acc512c 321 .sync = synchronize_rcu,
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322 .exp_sync = synchronize_rcu_expedited,
323 .call = call_rcu,
324 .cb_barrier = rcu_barrier,
bf66f18e 325 .fqs = rcu_force_quiescent_state,
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326 .stats = NULL,
327 .irq_capable = 1,
8e8be45e 328 .can_boost = rcu_can_boost(),
2ec1f2d9 329 .name = "rcu"
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330};
331
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332/*
333 * Definitions for rcu_bh torture testing.
334 */
335
a49a4af7 336static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
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337{
338 rcu_read_lock_bh();
339 return 0;
340}
341
a49a4af7 342static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
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343{
344 rcu_read_unlock_bh();
345}
346
347static int rcu_bh_torture_completed(void)
348{
349 return rcu_batches_completed_bh();
350}
351
352static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
353{
354 call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
355}
356
357static struct rcu_torture_ops rcu_bh_ops = {
2ec1f2d9 358 .init = rcu_sync_torture_init,
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359 .readlock = rcu_bh_torture_read_lock,
360 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
361 .readunlock = rcu_bh_torture_read_unlock,
362 .completed = rcu_bh_torture_completed,
363 .deferred_free = rcu_bh_torture_deferred_free,
bdf2a436 364 .sync = synchronize_rcu_bh,
2ec1f2d9 365 .exp_sync = synchronize_rcu_bh_expedited,
fae4b54f 366 .call = call_rcu_bh,
0acc512c 367 .cb_barrier = rcu_barrier_bh,
bf66f18e 368 .fqs = rcu_bh_force_quiescent_state,
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369 .stats = NULL,
370 .irq_capable = 1,
371 .name = "rcu_bh"
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372};
373
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374/*
375 * Don't even think about trying any of these in real life!!!
376 * The names includes "busted", and they really means it!
377 * The only purpose of these functions is to provide a buggy RCU
378 * implementation to make sure that rcutorture correctly emits
379 * buggy-RCU error messages.
380 */
381static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
382{
383 /* This is a deliberate bug for testing purposes only! */
384 rcu_torture_cb(&p->rtort_rcu);
385}
386
387static void synchronize_rcu_busted(void)
388{
389 /* This is a deliberate bug for testing purposes only! */
390}
391
392static void
393call_rcu_busted(struct rcu_head *head, void (*func)(struct rcu_head *rcu))
394{
395 /* This is a deliberate bug for testing purposes only! */
396 func(head);
397}
398
399static struct rcu_torture_ops rcu_busted_ops = {
400 .init = rcu_sync_torture_init,
401 .readlock = rcu_torture_read_lock,
402 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
403 .readunlock = rcu_torture_read_unlock,
404 .completed = rcu_no_completed,
405 .deferred_free = rcu_busted_torture_deferred_free,
406 .sync = synchronize_rcu_busted,
407 .exp_sync = synchronize_rcu_busted,
408 .call = call_rcu_busted,
409 .cb_barrier = NULL,
410 .fqs = NULL,
411 .stats = NULL,
412 .irq_capable = 1,
413 .name = "rcu_busted"
414};
415
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416/*
417 * Definitions for srcu torture testing.
418 */
419
cda4dc81 420DEFINE_STATIC_SRCU(srcu_ctl);
b2896d2e 421
012d3ca8 422static int srcu_torture_read_lock(void) __acquires(&srcu_ctl)
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423{
424 return srcu_read_lock(&srcu_ctl);
425}
426
51b1130e 427static void srcu_read_delay(struct torture_random_state *rrsp)
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428{
429 long delay;
430 const long uspertick = 1000000 / HZ;
431 const long longdelay = 10;
432
433 /* We want there to be long-running readers, but not all the time. */
434
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435 delay = torture_random(rrsp) %
436 (nrealreaders * 2 * longdelay * uspertick);
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437 if (!delay)
438 schedule_timeout_interruptible(longdelay);
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439 else
440 rcu_read_delay(rrsp);
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441}
442
012d3ca8 443static void srcu_torture_read_unlock(int idx) __releases(&srcu_ctl)
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444{
445 srcu_read_unlock(&srcu_ctl, idx);
446}
447
448static int srcu_torture_completed(void)
449{
450 return srcu_batches_completed(&srcu_ctl);
451}
452
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453static void srcu_torture_deferred_free(struct rcu_torture *rp)
454{
455 call_srcu(&srcu_ctl, &rp->rtort_rcu, rcu_torture_cb);
456}
457
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458static void srcu_torture_synchronize(void)
459{
460 synchronize_srcu(&srcu_ctl);
461}
462
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463static void srcu_torture_call(struct rcu_head *head,
464 void (*func)(struct rcu_head *head))
465{
466 call_srcu(&srcu_ctl, head, func);
467}
468
469static void srcu_torture_barrier(void)
470{
471 srcu_barrier(&srcu_ctl);
472}
473
d1008950 474static void srcu_torture_stats(char *page)
b2896d2e 475{
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476 int cpu;
477 int idx = srcu_ctl.completed & 0x1;
478
d1008950 479 page += sprintf(page, "%s%s per-CPU(idx=%d):",
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480 torture_type, TORTURE_FLAG, idx);
481 for_each_possible_cpu(cpu) {
d1008950 482 page += sprintf(page, " %d(%lu,%lu)", cpu,
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483 per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx],
484 per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx]);
485 }
d1008950 486 sprintf(page, "\n");
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487}
488
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489static void srcu_torture_synchronize_expedited(void)
490{
491 synchronize_srcu_expedited(&srcu_ctl);
492}
493
b2896d2e 494static struct rcu_torture_ops srcu_ops = {
cda4dc81 495 .init = rcu_sync_torture_init,
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496 .readlock = srcu_torture_read_lock,
497 .read_delay = srcu_read_delay,
498 .readunlock = srcu_torture_read_unlock,
499 .completed = srcu_torture_completed,
9059c940 500 .deferred_free = srcu_torture_deferred_free,
0acc512c 501 .sync = srcu_torture_synchronize,
2ec1f2d9 502 .exp_sync = srcu_torture_synchronize_expedited,
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503 .call = srcu_torture_call,
504 .cb_barrier = srcu_torture_barrier,
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505 .stats = srcu_torture_stats,
506 .name = "srcu"
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507};
508
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509/*
510 * Definitions for sched torture testing.
511 */
512
513static int sched_torture_read_lock(void)
514{
515 preempt_disable();
516 return 0;
517}
518
519static void sched_torture_read_unlock(int idx)
520{
521 preempt_enable();
522}
523
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524static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
525{
526 call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
527}
528
4b6c2cca 529static struct rcu_torture_ops sched_ops = {
0acc512c 530 .init = rcu_sync_torture_init,
0acc512c
PM
531 .readlock = sched_torture_read_lock,
532 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
533 .readunlock = sched_torture_read_unlock,
d9a3da06 534 .completed = rcu_no_completed,
0acc512c 535 .deferred_free = rcu_sched_torture_deferred_free,
bdf2a436 536 .sync = synchronize_sched,
2ec1f2d9
PM
537 .exp_sync = synchronize_sched_expedited,
538 .call = call_rcu_sched,
0acc512c 539 .cb_barrier = rcu_barrier_sched,
bf66f18e 540 .fqs = rcu_sched_force_quiescent_state,
0acc512c
PM
541 .stats = NULL,
542 .irq_capable = 1,
543 .name = "sched"
4b6c2cca
JT
544};
545
8e8be45e
PM
546/*
547 * RCU torture priority-boost testing. Runs one real-time thread per
548 * CPU for moderate bursts, repeatedly registering RCU callbacks and
549 * spinning waiting for them to be invoked. If a given callback takes
550 * too long to be invoked, we assume that priority inversion has occurred.
551 */
552
553struct rcu_boost_inflight {
554 struct rcu_head rcu;
555 int inflight;
556};
557
558static void rcu_torture_boost_cb(struct rcu_head *head)
559{
560 struct rcu_boost_inflight *rbip =
561 container_of(head, struct rcu_boost_inflight, rcu);
562
563 smp_mb(); /* Ensure RCU-core accesses precede clearing ->inflight */
564 rbip->inflight = 0;
565}
566
567static int rcu_torture_boost(void *arg)
568{
569 unsigned long call_rcu_time;
570 unsigned long endtime;
571 unsigned long oldstarttime;
572 struct rcu_boost_inflight rbi = { .inflight = 0 };
573 struct sched_param sp;
574
5ccf60f2 575 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
8e8be45e
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576
577 /* Set real-time priority. */
578 sp.sched_priority = 1;
579 if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
5ccf60f2 580 VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!");
8e8be45e
PM
581 n_rcu_torture_boost_rterror++;
582 }
583
561190e3 584 init_rcu_head_on_stack(&rbi.rcu);
8e8be45e
PM
585 /* Each pass through the following loop does one boost-test cycle. */
586 do {
587 /* Wait for the next test interval. */
588 oldstarttime = boost_starttime;
93898fb1 589 while (ULONG_CMP_LT(jiffies, oldstarttime)) {
0e11c8e8 590 schedule_timeout_interruptible(oldstarttime - jiffies);
628edaa5 591 stutter_wait("rcu_torture_boost");
36970bb9 592 if (torture_must_stop())
8e8be45e
PM
593 goto checkwait;
594 }
595
596 /* Do one boost-test interval. */
597 endtime = oldstarttime + test_boost_duration * HZ;
598 call_rcu_time = jiffies;
93898fb1 599 while (ULONG_CMP_LT(jiffies, endtime)) {
8e8be45e
PM
600 /* If we don't have a callback in flight, post one. */
601 if (!rbi.inflight) {
602 smp_mb(); /* RCU core before ->inflight = 1. */
603 rbi.inflight = 1;
604 call_rcu(&rbi.rcu, rcu_torture_boost_cb);
605 if (jiffies - call_rcu_time >
606 test_boost_duration * HZ - HZ / 2) {
5ccf60f2 607 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
8e8be45e
PM
608 n_rcu_torture_boost_failure++;
609 }
610 call_rcu_time = jiffies;
611 }
612 cond_resched();
628edaa5 613 stutter_wait("rcu_torture_boost");
36970bb9 614 if (torture_must_stop())
8e8be45e
PM
615 goto checkwait;
616 }
617
618 /*
619 * Set the start time of the next test interval.
620 * Yes, this is vulnerable to long delays, but such
621 * delays simply cause a false negative for the next
622 * interval. Besides, we are running at RT priority,
623 * so delays should be relatively rare.
624 */
ab8f11e5
PM
625 while (oldstarttime == boost_starttime &&
626 !kthread_should_stop()) {
8e8be45e
PM
627 if (mutex_trylock(&boost_mutex)) {
628 boost_starttime = jiffies +
629 test_boost_interval * HZ;
630 n_rcu_torture_boosts++;
631 mutex_unlock(&boost_mutex);
632 break;
633 }
634 schedule_timeout_uninterruptible(1);
635 }
636
637 /* Go do the stutter. */
628edaa5 638checkwait: stutter_wait("rcu_torture_boost");
36970bb9 639 } while (!torture_must_stop());
8e8be45e
PM
640
641 /* Clean up and exit. */
7fafaac5
PM
642 while (!kthread_should_stop() || rbi.inflight) {
643 torture_shutdown_absorb("rcu_torture_boost");
8e8be45e 644 schedule_timeout_uninterruptible(1);
7fafaac5 645 }
8e8be45e 646 smp_mb(); /* order accesses to ->inflight before stack-frame death. */
9d68197c 647 destroy_rcu_head_on_stack(&rbi.rcu);
7fafaac5 648 torture_kthread_stopping("rcu_torture_boost");
8e8be45e
PM
649 return 0;
650}
651
bf66f18e
PM
652/*
653 * RCU torture force-quiescent-state kthread. Repeatedly induces
654 * bursts of calls to force_quiescent_state(), increasing the probability
655 * of occurrence of some important types of race conditions.
656 */
657static int
658rcu_torture_fqs(void *arg)
659{
660 unsigned long fqs_resume_time;
661 int fqs_burst_remaining;
662
5ccf60f2 663 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
bf66f18e
PM
664 do {
665 fqs_resume_time = jiffies + fqs_stutter * HZ;
93898fb1
PM
666 while (ULONG_CMP_LT(jiffies, fqs_resume_time) &&
667 !kthread_should_stop()) {
bf66f18e
PM
668 schedule_timeout_interruptible(1);
669 }
670 fqs_burst_remaining = fqs_duration;
93898fb1
PM
671 while (fqs_burst_remaining > 0 &&
672 !kthread_should_stop()) {
bf66f18e
PM
673 cur_ops->fqs();
674 udelay(fqs_holdoff);
675 fqs_burst_remaining -= fqs_holdoff;
676 }
628edaa5 677 stutter_wait("rcu_torture_fqs");
36970bb9 678 } while (!torture_must_stop());
7fafaac5 679 torture_kthread_stopping("rcu_torture_fqs");
bf66f18e
PM
680 return 0;
681}
682
a241ec65
PM
683/*
684 * RCU torture writer kthread. Repeatedly substitutes a new structure
685 * for that pointed to by rcu_torture_current, freeing the old structure
686 * after a series of grace periods (the "pipeline").
687 */
688static int
689rcu_torture_writer(void *arg)
690{
2ec1f2d9 691 bool exp;
a241ec65 692 int i;
a241ec65 693 struct rcu_torture *rp;
2ec1f2d9 694 struct rcu_torture *rp1;
a241ec65 695 struct rcu_torture *old_rp;
51b1130e 696 static DEFINE_TORTURE_RANDOM(rand);
a241ec65 697
5ccf60f2 698 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
d277d868 699 set_user_nice(current, MAX_NICE);
dbdf65b1 700
a241ec65
PM
701 do {
702 schedule_timeout_uninterruptible(1);
a71fca58
PM
703 rp = rcu_torture_alloc();
704 if (rp == NULL)
a241ec65
PM
705 continue;
706 rp->rtort_pipe_count = 0;
51b1130e 707 udelay(torture_random(&rand) & 0x3ff);
0ddea0ea
PM
708 old_rp = rcu_dereference_check(rcu_torture_current,
709 current == writer_task);
996417d2 710 rp->rtort_mbtest = 1;
a241ec65 711 rcu_assign_pointer(rcu_torture_current, rp);
9b2619af 712 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
c8e5b163 713 if (old_rp) {
a241ec65
PM
714 i = old_rp->rtort_pipe_count;
715 if (i > RCU_TORTURE_PIPE_LEN)
716 i = RCU_TORTURE_PIPE_LEN;
717 atomic_inc(&rcu_torture_wcount[i]);
718 old_rp->rtort_pipe_count++;
2ec1f2d9 719 if (gp_normal == gp_exp)
51b1130e 720 exp = !!(torture_random(&rand) & 0x80);
2ec1f2d9
PM
721 else
722 exp = gp_exp;
723 if (!exp) {
724 cur_ops->deferred_free(old_rp);
725 } else {
726 cur_ops->exp_sync();
727 list_add(&old_rp->rtort_free,
728 &rcu_torture_removed);
729 list_for_each_entry_safe(rp, rp1,
730 &rcu_torture_removed,
731 rtort_free) {
732 i = rp->rtort_pipe_count;
733 if (i > RCU_TORTURE_PIPE_LEN)
734 i = RCU_TORTURE_PIPE_LEN;
735 atomic_inc(&rcu_torture_wcount[i]);
736 if (++rp->rtort_pipe_count >=
737 RCU_TORTURE_PIPE_LEN) {
738 rp->rtort_mbtest = 0;
739 list_del(&rp->rtort_free);
740 rcu_torture_free(rp);
741 }
742 }
743 }
a241ec65 744 }
4a298656 745 rcutorture_record_progress(++rcu_torture_current_version);
628edaa5 746 stutter_wait("rcu_torture_writer");
36970bb9 747 } while (!torture_must_stop());
7fafaac5 748 torture_kthread_stopping("rcu_torture_writer");
a241ec65
PM
749 return 0;
750}
751
b772e1dd
JT
752/*
753 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
754 * delay between calls.
755 */
756static int
757rcu_torture_fakewriter(void *arg)
758{
51b1130e 759 DEFINE_TORTURE_RANDOM(rand);
b772e1dd 760
5ccf60f2 761 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
d277d868 762 set_user_nice(current, MAX_NICE);
b772e1dd
JT
763
764 do {
51b1130e
PM
765 schedule_timeout_uninterruptible(1 + torture_random(&rand)%10);
766 udelay(torture_random(&rand) & 0x3ff);
72472a02 767 if (cur_ops->cb_barrier != NULL &&
51b1130e 768 torture_random(&rand) % (nfakewriters * 8) == 0) {
72472a02 769 cur_ops->cb_barrier();
2ec1f2d9 770 } else if (gp_normal == gp_exp) {
51b1130e 771 if (torture_random(&rand) & 0x80)
2ec1f2d9
PM
772 cur_ops->sync();
773 else
774 cur_ops->exp_sync();
775 } else if (gp_normal) {
72472a02 776 cur_ops->sync();
2ec1f2d9
PM
777 } else {
778 cur_ops->exp_sync();
779 }
628edaa5 780 stutter_wait("rcu_torture_fakewriter");
36970bb9 781 } while (!torture_must_stop());
b772e1dd 782
7fafaac5 783 torture_kthread_stopping("rcu_torture_fakewriter");
b772e1dd
JT
784 return 0;
785}
786
91afaf30
PM
787void rcutorture_trace_dump(void)
788{
789 static atomic_t beenhere = ATOMIC_INIT(0);
790
791 if (atomic_read(&beenhere))
792 return;
793 if (atomic_xchg(&beenhere, 1) != 0)
794 return;
91afaf30
PM
795 ftrace_dump(DUMP_ALL);
796}
797
0729fbf3
PM
798/*
799 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
800 * incrementing the corresponding element of the pipeline array. The
801 * counter in the element should never be greater than 1, otherwise, the
802 * RCU implementation is broken.
803 */
804static void rcu_torture_timer(unsigned long unused)
805{
806 int idx;
807 int completed;
52494535 808 int completed_end;
51b1130e 809 static DEFINE_TORTURE_RANDOM(rand);
0729fbf3
PM
810 static DEFINE_SPINLOCK(rand_lock);
811 struct rcu_torture *p;
812 int pipe_count;
52494535 813 unsigned long long ts;
0729fbf3
PM
814
815 idx = cur_ops->readlock();
816 completed = cur_ops->completed();
e4aa0da3 817 ts = rcu_trace_clock_local();
632ee200 818 p = rcu_dereference_check(rcu_torture_current,
632ee200
PM
819 rcu_read_lock_bh_held() ||
820 rcu_read_lock_sched_held() ||
821 srcu_read_lock_held(&srcu_ctl));
0729fbf3
PM
822 if (p == NULL) {
823 /* Leave because rcu_torture_writer is not yet underway */
824 cur_ops->readunlock(idx);
825 return;
826 }
827 if (p->rtort_mbtest == 0)
828 atomic_inc(&n_rcu_torture_mberror);
829 spin_lock(&rand_lock);
0acc512c 830 cur_ops->read_delay(&rand);
0729fbf3
PM
831 n_rcu_torture_timers++;
832 spin_unlock(&rand_lock);
833 preempt_disable();
834 pipe_count = p->rtort_pipe_count;
835 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
836 /* Should not happen, but... */
837 pipe_count = RCU_TORTURE_PIPE_LEN;
838 }
52494535
PM
839 completed_end = cur_ops->completed();
840 if (pipe_count > 1) {
52494535
PM
841 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, ts,
842 completed, completed_end);
91afaf30 843 rcutorture_trace_dump();
52494535 844 }
dd17c8f7 845 __this_cpu_inc(rcu_torture_count[pipe_count]);
52494535 846 completed = completed_end - completed;
0729fbf3
PM
847 if (completed > RCU_TORTURE_PIPE_LEN) {
848 /* Should not happen, but... */
849 completed = RCU_TORTURE_PIPE_LEN;
850 }
dd17c8f7 851 __this_cpu_inc(rcu_torture_batch[completed]);
0729fbf3
PM
852 preempt_enable();
853 cur_ops->readunlock(idx);
854}
855
a241ec65
PM
856/*
857 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
858 * incrementing the corresponding element of the pipeline array. The
859 * counter in the element should never be greater than 1, otherwise, the
860 * RCU implementation is broken.
861 */
862static int
863rcu_torture_reader(void *arg)
864{
865 int completed;
52494535 866 int completed_end;
72e9bb54 867 int idx;
51b1130e 868 DEFINE_TORTURE_RANDOM(rand);
a241ec65
PM
869 struct rcu_torture *p;
870 int pipe_count;
0729fbf3 871 struct timer_list t;
52494535 872 unsigned long long ts;
a241ec65 873
5ccf60f2 874 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
d277d868 875 set_user_nice(current, MAX_NICE);
0acc512c 876 if (irqreader && cur_ops->irq_capable)
0729fbf3 877 setup_timer_on_stack(&t, rcu_torture_timer, 0);
dbdf65b1 878
a241ec65 879 do {
0acc512c 880 if (irqreader && cur_ops->irq_capable) {
0729fbf3 881 if (!timer_pending(&t))
6155fec9 882 mod_timer(&t, jiffies + 1);
0729fbf3 883 }
72e9bb54
PM
884 idx = cur_ops->readlock();
885 completed = cur_ops->completed();
e4aa0da3 886 ts = rcu_trace_clock_local();
632ee200 887 p = rcu_dereference_check(rcu_torture_current,
632ee200
PM
888 rcu_read_lock_bh_held() ||
889 rcu_read_lock_sched_held() ||
890 srcu_read_lock_held(&srcu_ctl));
a241ec65
PM
891 if (p == NULL) {
892 /* Wait for rcu_torture_writer to get underway */
72e9bb54 893 cur_ops->readunlock(idx);
a241ec65
PM
894 schedule_timeout_interruptible(HZ);
895 continue;
896 }
996417d2
PM
897 if (p->rtort_mbtest == 0)
898 atomic_inc(&n_rcu_torture_mberror);
0acc512c 899 cur_ops->read_delay(&rand);
a241ec65
PM
900 preempt_disable();
901 pipe_count = p->rtort_pipe_count;
902 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
903 /* Should not happen, but... */
904 pipe_count = RCU_TORTURE_PIPE_LEN;
905 }
52494535
PM
906 completed_end = cur_ops->completed();
907 if (pipe_count > 1) {
52494535
PM
908 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
909 ts, completed, completed_end);
91afaf30 910 rcutorture_trace_dump();
52494535 911 }
dd17c8f7 912 __this_cpu_inc(rcu_torture_count[pipe_count]);
52494535 913 completed = completed_end - completed;
a241ec65
PM
914 if (completed > RCU_TORTURE_PIPE_LEN) {
915 /* Should not happen, but... */
916 completed = RCU_TORTURE_PIPE_LEN;
917 }
dd17c8f7 918 __this_cpu_inc(rcu_torture_batch[completed]);
a241ec65 919 preempt_enable();
72e9bb54 920 cur_ops->readunlock(idx);
a241ec65 921 schedule();
628edaa5 922 stutter_wait("rcu_torture_reader");
36970bb9 923 } while (!torture_must_stop());
0acc512c 924 if (irqreader && cur_ops->irq_capable)
0729fbf3 925 del_timer_sync(&t);
7fafaac5 926 torture_kthread_stopping("rcu_torture_reader");
a241ec65
PM
927 return 0;
928}
929
930/*
931 * Create an RCU-torture statistics message in the specified buffer.
932 */
d1008950 933static void
a241ec65
PM
934rcu_torture_printk(char *page)
935{
a241ec65
PM
936 int cpu;
937 int i;
938 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
939 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
940
0a945022 941 for_each_possible_cpu(cpu) {
a241ec65
PM
942 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
943 pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
944 batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
945 }
946 }
947 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
948 if (pipesummary[i] != 0)
949 break;
950 }
d1008950
CG
951 page += sprintf(page, "%s%s ", torture_type, TORTURE_FLAG);
952 page += sprintf(page,
5cf05ad7 953 "rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
a241ec65
PM
954 rcu_torture_current,
955 rcu_torture_current_version,
956 list_empty(&rcu_torture_freelist),
957 atomic_read(&n_rcu_torture_alloc),
958 atomic_read(&n_rcu_torture_alloc_fail),
5cf05ad7 959 atomic_read(&n_rcu_torture_free));
d1008950 960 page += sprintf(page, "rtmbe: %d rtbke: %ld rtbre: %ld ",
0729fbf3 961 atomic_read(&n_rcu_torture_mberror),
8e8be45e 962 n_rcu_torture_boost_ktrerror,
5cf05ad7 963 n_rcu_torture_boost_rterror);
d1008950 964 page += sprintf(page, "rtbf: %ld rtb: %ld nt: %ld ",
8e8be45e
PM
965 n_rcu_torture_boost_failure,
966 n_rcu_torture_boosts,
5cf05ad7 967 n_rcu_torture_timers);
2e9e8081 968 page = torture_onoff_stats(page);
d1008950 969 page += sprintf(page, "barrier: %ld/%ld:%ld",
fae4b54f
PM
970 n_barrier_successes,
971 n_barrier_attempts,
972 n_rcu_torture_barrier_error);
d1008950 973 page += sprintf(page, "\n%s%s ", torture_type, TORTURE_FLAG);
8e8be45e 974 if (atomic_read(&n_rcu_torture_mberror) != 0 ||
fae4b54f 975 n_rcu_torture_barrier_error != 0 ||
8e8be45e
PM
976 n_rcu_torture_boost_ktrerror != 0 ||
977 n_rcu_torture_boost_rterror != 0 ||
fae4b54f
PM
978 n_rcu_torture_boost_failure != 0 ||
979 i > 1) {
d1008950 980 page += sprintf(page, "!!! ");
996417d2 981 atomic_inc(&n_rcu_torture_error);
5af970a4 982 WARN_ON_ONCE(1);
996417d2 983 }
d1008950 984 page += sprintf(page, "Reader Pipe: ");
a241ec65 985 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
d1008950
CG
986 page += sprintf(page, " %ld", pipesummary[i]);
987 page += sprintf(page, "\n%s%s ", torture_type, TORTURE_FLAG);
988 page += sprintf(page, "Reader Batch: ");
72e9bb54 989 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
d1008950
CG
990 page += sprintf(page, " %ld", batchsummary[i]);
991 page += sprintf(page, "\n%s%s ", torture_type, TORTURE_FLAG);
992 page += sprintf(page, "Free-Block Circulation: ");
a241ec65 993 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
d1008950 994 page += sprintf(page, " %d",
a241ec65
PM
995 atomic_read(&rcu_torture_wcount[i]));
996 }
d1008950 997 page += sprintf(page, "\n");
c8e5b163 998 if (cur_ops->stats)
d1008950 999 cur_ops->stats(page);
a241ec65
PM
1000}
1001
1002/*
1003 * Print torture statistics. Caller must ensure that there is only
1004 * one call to this function at a given time!!! This is normally
1005 * accomplished by relying on the module system to only have one copy
1006 * of the module loaded, and then by giving the rcu_torture_stats
1007 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1008 * thread is not running).
1009 */
1010static void
1011rcu_torture_stats_print(void)
1012{
d1008950
CG
1013 int size = nr_cpu_ids * 200 + 8192;
1014 char *buf;
a241ec65 1015
d1008950
CG
1016 buf = kmalloc(size, GFP_KERNEL);
1017 if (!buf) {
1018 pr_err("rcu-torture: Out of memory, need: %d", size);
1019 return;
1020 }
1021 rcu_torture_printk(buf);
1022 pr_alert("%s", buf);
1023 kfree(buf);
a241ec65
PM
1024}
1025
1026/*
1027 * Periodically prints torture statistics, if periodic statistics printing
1028 * was specified via the stat_interval module parameter.
a241ec65
PM
1029 */
1030static int
1031rcu_torture_stats(void *arg)
1032{
5ccf60f2 1033 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
a241ec65
PM
1034 do {
1035 schedule_timeout_interruptible(stat_interval * HZ);
1036 rcu_torture_stats_print();
f67a3356 1037 torture_shutdown_absorb("rcu_torture_stats");
36970bb9 1038 } while (!torture_must_stop());
7fafaac5 1039 torture_kthread_stopping("rcu_torture_stats");
d120f65f
PM
1040 return 0;
1041}
1042
95c38322 1043static inline void
e66c33d5 1044rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
95c38322 1045{
2caa1e44
PM
1046 pr_alert("%s" TORTURE_FLAG
1047 "--- %s: nreaders=%d nfakewriters=%d "
1048 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1049 "shuffle_interval=%d stutter=%d irqreader=%d "
1050 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1051 "test_boost=%d/%d test_boost_interval=%d "
1052 "test_boost_duration=%d shutdown_secs=%d "
67afeed2
PM
1053 "stall_cpu=%d stall_cpu_holdoff=%d "
1054 "n_barrier_cbs=%d "
2caa1e44
PM
1055 "onoff_interval=%d onoff_holdoff=%d\n",
1056 torture_type, tag, nrealreaders, nfakewriters,
1057 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1058 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1059 test_boost, cur_ops->can_boost,
1060 test_boost_interval, test_boost_duration, shutdown_secs,
67afeed2
PM
1061 stall_cpu, stall_cpu_holdoff,
1062 n_barrier_cbs,
2caa1e44 1063 onoff_interval, onoff_holdoff);
95c38322
PM
1064}
1065
8e8be45e
PM
1066static void rcutorture_booster_cleanup(int cpu)
1067{
1068 struct task_struct *t;
1069
1070 if (boost_tasks[cpu] == NULL)
1071 return;
1072 mutex_lock(&boost_mutex);
8e8be45e
PM
1073 t = boost_tasks[cpu];
1074 boost_tasks[cpu] = NULL;
1075 mutex_unlock(&boost_mutex);
1076
1077 /* This must be outside of the mutex, otherwise deadlock! */
9c029b86 1078 torture_stop_kthread(rcu_torture_boost, t);
8e8be45e
PM
1079}
1080
1081static int rcutorture_booster_init(int cpu)
1082{
1083 int retval;
1084
1085 if (boost_tasks[cpu] != NULL)
1086 return 0; /* Already created, nothing more to do. */
1087
1088 /* Don't allow time recalculation while creating a new task. */
1089 mutex_lock(&boost_mutex);
5ccf60f2 1090 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
1f288094
ED
1091 boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
1092 cpu_to_node(cpu),
1093 "rcu_torture_boost");
8e8be45e
PM
1094 if (IS_ERR(boost_tasks[cpu])) {
1095 retval = PTR_ERR(boost_tasks[cpu]);
5ccf60f2 1096 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
8e8be45e
PM
1097 n_rcu_torture_boost_ktrerror++;
1098 boost_tasks[cpu] = NULL;
1099 mutex_unlock(&boost_mutex);
1100 return retval;
1101 }
1102 kthread_bind(boost_tasks[cpu], cpu);
1103 wake_up_process(boost_tasks[cpu]);
1104 mutex_unlock(&boost_mutex);
1105 return 0;
1106}
1107
c13f3757
PM
1108/*
1109 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
1110 * induces a CPU stall for the time specified by stall_cpu.
1111 */
49fb4c62 1112static int rcu_torture_stall(void *args)
c13f3757
PM
1113{
1114 unsigned long stop_at;
1115
5ccf60f2 1116 VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
c13f3757 1117 if (stall_cpu_holdoff > 0) {
5ccf60f2 1118 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
c13f3757 1119 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
5ccf60f2 1120 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
c13f3757
PM
1121 }
1122 if (!kthread_should_stop()) {
1123 stop_at = get_seconds() + stall_cpu;
1124 /* RCU CPU stall is expected behavior in following code. */
2caa1e44 1125 pr_alert("rcu_torture_stall start.\n");
c13f3757
PM
1126 rcu_read_lock();
1127 preempt_disable();
1128 while (ULONG_CMP_LT(get_seconds(), stop_at))
1129 continue; /* Induce RCU CPU stall warning. */
1130 preempt_enable();
1131 rcu_read_unlock();
2caa1e44 1132 pr_alert("rcu_torture_stall end.\n");
c13f3757 1133 }
f67a3356 1134 torture_shutdown_absorb("rcu_torture_stall");
c13f3757
PM
1135 while (!kthread_should_stop())
1136 schedule_timeout_interruptible(10 * HZ);
1137 return 0;
1138}
1139
1140/* Spawn CPU-stall kthread, if stall_cpu specified. */
1141static int __init rcu_torture_stall_init(void)
1142{
c13f3757
PM
1143 if (stall_cpu <= 0)
1144 return 0;
47cf29b9 1145 return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
c13f3757
PM
1146}
1147
fae4b54f
PM
1148/* Callback function for RCU barrier testing. */
1149void rcu_torture_barrier_cbf(struct rcu_head *rcu)
1150{
1151 atomic_inc(&barrier_cbs_invoked);
1152}
1153
1154/* kthread function to register callbacks used to test RCU barriers. */
1155static int rcu_torture_barrier_cbs(void *arg)
1156{
1157 long myid = (long)arg;
c6ebcbb6 1158 bool lastphase = 0;
78e4bc34 1159 bool newphase;
fae4b54f
PM
1160 struct rcu_head rcu;
1161
1162 init_rcu_head_on_stack(&rcu);
5ccf60f2 1163 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
d277d868 1164 set_user_nice(current, MAX_NICE);
fae4b54f
PM
1165 do {
1166 wait_event(barrier_cbs_wq[myid],
78e4bc34
PM
1167 (newphase =
1168 ACCESS_ONCE(barrier_phase)) != lastphase ||
36970bb9 1169 torture_must_stop());
78e4bc34 1170 lastphase = newphase;
c6ebcbb6 1171 smp_mb(); /* ensure barrier_phase load before ->call(). */
36970bb9 1172 if (torture_must_stop())
fae4b54f
PM
1173 break;
1174 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
1175 if (atomic_dec_and_test(&barrier_cbs_count))
1176 wake_up(&barrier_wq);
36970bb9 1177 } while (!torture_must_stop());
fae4b54f
PM
1178 cur_ops->cb_barrier();
1179 destroy_rcu_head_on_stack(&rcu);
7fafaac5 1180 torture_kthread_stopping("rcu_torture_barrier_cbs");
fae4b54f
PM
1181 return 0;
1182}
1183
1184/* kthread function to drive and coordinate RCU barrier testing. */
1185static int rcu_torture_barrier(void *arg)
1186{
1187 int i;
1188
5ccf60f2 1189 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
fae4b54f
PM
1190 do {
1191 atomic_set(&barrier_cbs_invoked, 0);
1192 atomic_set(&barrier_cbs_count, n_barrier_cbs);
c6ebcbb6
PM
1193 smp_mb(); /* Ensure barrier_phase after prior assignments. */
1194 barrier_phase = !barrier_phase;
fae4b54f
PM
1195 for (i = 0; i < n_barrier_cbs; i++)
1196 wake_up(&barrier_cbs_wq[i]);
1197 wait_event(barrier_wq,
1198 atomic_read(&barrier_cbs_count) == 0 ||
36970bb9
PM
1199 torture_must_stop());
1200 if (torture_must_stop())
fae4b54f
PM
1201 break;
1202 n_barrier_attempts++;
78e4bc34 1203 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
fae4b54f
PM
1204 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
1205 n_rcu_torture_barrier_error++;
1206 WARN_ON_ONCE(1);
1207 }
1208 n_barrier_successes++;
1209 schedule_timeout_interruptible(HZ / 10);
36970bb9 1210 } while (!torture_must_stop());
7fafaac5 1211 torture_kthread_stopping("rcu_torture_barrier");
fae4b54f
PM
1212 return 0;
1213}
1214
1215/* Initialize RCU barrier testing. */
1216static int rcu_torture_barrier_init(void)
1217{
1218 int i;
1219 int ret;
1220
1221 if (n_barrier_cbs == 0)
1222 return 0;
1223 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
2caa1e44
PM
1224 pr_alert("%s" TORTURE_FLAG
1225 " Call or barrier ops missing for %s,\n",
1226 torture_type, cur_ops->name);
1227 pr_alert("%s" TORTURE_FLAG
1228 " RCU barrier testing omitted from run.\n",
1229 torture_type);
fae4b54f
PM
1230 return 0;
1231 }
1232 atomic_set(&barrier_cbs_count, 0);
1233 atomic_set(&barrier_cbs_invoked, 0);
1234 barrier_cbs_tasks =
1235 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_tasks[0]),
1236 GFP_KERNEL);
1237 barrier_cbs_wq =
1238 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_wq[0]),
1239 GFP_KERNEL);
de5e6437 1240 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
fae4b54f
PM
1241 return -ENOMEM;
1242 for (i = 0; i < n_barrier_cbs; i++) {
1243 init_waitqueue_head(&barrier_cbs_wq[i]);
47cf29b9
PM
1244 ret = torture_create_kthread(rcu_torture_barrier_cbs,
1245 (void *)(long)i,
1246 barrier_cbs_tasks[i]);
1247 if (ret)
fae4b54f 1248 return ret;
fae4b54f 1249 }
47cf29b9 1250 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
fae4b54f
PM
1251}
1252
1253/* Clean up after RCU barrier testing. */
1254static void rcu_torture_barrier_cleanup(void)
1255{
1256 int i;
1257
9c029b86 1258 torture_stop_kthread(rcu_torture_barrier, barrier_task);
fae4b54f 1259 if (barrier_cbs_tasks != NULL) {
9c029b86
PM
1260 for (i = 0; i < n_barrier_cbs; i++)
1261 torture_stop_kthread(rcu_torture_barrier_cbs,
1262 barrier_cbs_tasks[i]);
fae4b54f
PM
1263 kfree(barrier_cbs_tasks);
1264 barrier_cbs_tasks = NULL;
1265 }
1266 if (barrier_cbs_wq != NULL) {
1267 kfree(barrier_cbs_wq);
1268 barrier_cbs_wq = NULL;
1269 }
1270}
1271
8e8be45e
PM
1272static int rcutorture_cpu_notify(struct notifier_block *self,
1273 unsigned long action, void *hcpu)
1274{
1275 long cpu = (long)hcpu;
1276
1277 switch (action) {
1278 case CPU_ONLINE:
1279 case CPU_DOWN_FAILED:
1280 (void)rcutorture_booster_init(cpu);
1281 break;
1282 case CPU_DOWN_PREPARE:
1283 rcutorture_booster_cleanup(cpu);
1284 break;
1285 default:
1286 break;
1287 }
1288 return NOTIFY_OK;
1289}
1290
1291static struct notifier_block rcutorture_cpu_nb = {
1292 .notifier_call = rcutorture_cpu_notify,
1293};
1294
a241ec65
PM
1295static void
1296rcu_torture_cleanup(void)
1297{
1298 int i;
1299
4a298656 1300 rcutorture_record_test_transition();
cc47ae08 1301 if (torture_cleanup()) {
343e9099
PM
1302 if (cur_ops->cb_barrier != NULL)
1303 cur_ops->cb_barrier();
1304 return;
1305 }
d84f5203 1306
fae4b54f 1307 rcu_torture_barrier_cleanup();
9c029b86 1308 torture_stop_kthread(rcu_torture_stall, stall_task);
9c029b86 1309 torture_stop_kthread(rcu_torture_writer, writer_task);
a241ec65 1310
c8e5b163 1311 if (reader_tasks) {
9c029b86
PM
1312 for (i = 0; i < nrealreaders; i++)
1313 torture_stop_kthread(rcu_torture_reader,
1314 reader_tasks[i]);
a241ec65 1315 kfree(reader_tasks);
a241ec65
PM
1316 }
1317 rcu_torture_current = NULL;
1318
c8e5b163 1319 if (fakewriter_tasks) {
b772e1dd 1320 for (i = 0; i < nfakewriters; i++) {
9c029b86
PM
1321 torture_stop_kthread(rcu_torture_fakewriter,
1322 fakewriter_tasks[i]);
b772e1dd
JT
1323 }
1324 kfree(fakewriter_tasks);
1325 fakewriter_tasks = NULL;
1326 }
1327
9c029b86
PM
1328 torture_stop_kthread(rcu_torture_stats, stats_task);
1329 torture_stop_kthread(rcu_torture_fqs, fqs_task);
8e8be45e
PM
1330 if ((test_boost == 1 && cur_ops->can_boost) ||
1331 test_boost == 2) {
1332 unregister_cpu_notifier(&rcutorture_cpu_nb);
1333 for_each_possible_cpu(i)
1334 rcutorture_booster_cleanup(i);
1335 }
bf66f18e 1336
a241ec65 1337 /* Wait for all RCU callbacks to fire. */
2326974d
PM
1338
1339 if (cur_ops->cb_barrier != NULL)
1340 cur_ops->cb_barrier();
a241ec65 1341
a241ec65 1342 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
72e9bb54 1343
fae4b54f 1344 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
8e8be45e 1345 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
2e9e8081 1346 else if (torture_onoff_failures())
091541bb
PM
1347 rcu_torture_print_module_parms(cur_ops,
1348 "End of test: RCU_HOTPLUG");
95c38322 1349 else
8e8be45e 1350 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
a241ec65
PM
1351}
1352
d2818df1
PM
1353#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1354static void rcu_torture_leak_cb(struct rcu_head *rhp)
1355{
1356}
1357
1358static void rcu_torture_err_cb(struct rcu_head *rhp)
1359{
1360 /*
1361 * This -might- happen due to race conditions, but is unlikely.
1362 * The scenario that leads to this happening is that the
1363 * first of the pair of duplicate callbacks is queued,
1364 * someone else starts a grace period that includes that
1365 * callback, then the second of the pair must wait for the
1366 * next grace period. Unlikely, but can happen. If it
1367 * does happen, the debug-objects subsystem won't have splatted.
1368 */
1369 pr_alert("rcutorture: duplicated callback was invoked.\n");
1370}
1371#endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1372
1373/*
1374 * Verify that double-free causes debug-objects to complain, but only
1375 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
1376 * cannot be carried out.
1377 */
1378static void rcu_test_debug_objects(void)
1379{
1380#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1381 struct rcu_head rh1;
1382 struct rcu_head rh2;
1383
1384 init_rcu_head_on_stack(&rh1);
1385 init_rcu_head_on_stack(&rh2);
1386 pr_alert("rcutorture: WARN: Duplicate call_rcu() test starting.\n");
1387
1388 /* Try to queue the rh2 pair of callbacks for the same grace period. */
1389 preempt_disable(); /* Prevent preemption from interrupting test. */
1390 rcu_read_lock(); /* Make it impossible to finish a grace period. */
1391 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
1392 local_irq_disable(); /* Make it harder to start a new grace period. */
1393 call_rcu(&rh2, rcu_torture_leak_cb);
1394 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
1395 local_irq_enable();
1396 rcu_read_unlock();
1397 preempt_enable();
1398
1399 /* Wait for them all to get done so we can safely return. */
1400 rcu_barrier();
1401 pr_alert("rcutorture: WARN: Duplicate call_rcu() test complete.\n");
1402 destroy_rcu_head_on_stack(&rh1);
1403 destroy_rcu_head_on_stack(&rh2);
1404#else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1405 pr_alert("rcutorture: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n");
1406#endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1407}
1408
6f8bc500 1409static int __init
a241ec65
PM
1410rcu_torture_init(void)
1411{
1412 int i;
1413 int cpu;
1414 int firsterr = 0;
2ec1f2d9 1415 static struct rcu_torture_ops *torture_ops[] = {
ff20e251 1416 &rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &sched_ops,
2ec1f2d9 1417 };
a241ec65 1418
628edaa5 1419 torture_init_begin(torture_type, verbose, &rcutorture_runnable);
343e9099 1420
a241ec65 1421 /* Process args and tell the world that the torturer is on the job. */
ade5fb81 1422 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
72e9bb54 1423 cur_ops = torture_ops[i];
ade5fb81 1424 if (strcmp(torture_type, cur_ops->name) == 0)
72e9bb54 1425 break;
72e9bb54 1426 }
ade5fb81 1427 if (i == ARRAY_SIZE(torture_ops)) {
2caa1e44
PM
1428 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
1429 torture_type);
1430 pr_alert("rcu-torture types:");
cf886c44 1431 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
2caa1e44
PM
1432 pr_alert(" %s", torture_ops[i]->name);
1433 pr_alert("\n");
b5daa8f3 1434 torture_init_end();
a71fca58 1435 return -EINVAL;
72e9bb54 1436 }
bf66f18e 1437 if (cur_ops->fqs == NULL && fqs_duration != 0) {
2caa1e44 1438 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
bf66f18e
PM
1439 fqs_duration = 0;
1440 }
c8e5b163 1441 if (cur_ops->init)
72e9bb54
PM
1442 cur_ops->init(); /* no "goto unwind" prior to this point!!! */
1443
a241ec65
PM
1444 if (nreaders >= 0)
1445 nrealreaders = nreaders;
1446 else
1447 nrealreaders = 2 * num_online_cpus();
8e8be45e 1448 rcu_torture_print_module_parms(cur_ops, "Start of test");
a241ec65
PM
1449
1450 /* Set up the freelist. */
1451
1452 INIT_LIST_HEAD(&rcu_torture_freelist);
788e770e 1453 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
996417d2 1454 rcu_tortures[i].rtort_mbtest = 0;
a241ec65
PM
1455 list_add_tail(&rcu_tortures[i].rtort_free,
1456 &rcu_torture_freelist);
1457 }
1458
1459 /* Initialize the statistics so that each run gets its own numbers. */
1460
1461 rcu_torture_current = NULL;
1462 rcu_torture_current_version = 0;
1463 atomic_set(&n_rcu_torture_alloc, 0);
1464 atomic_set(&n_rcu_torture_alloc_fail, 0);
1465 atomic_set(&n_rcu_torture_free, 0);
996417d2
PM
1466 atomic_set(&n_rcu_torture_mberror, 0);
1467 atomic_set(&n_rcu_torture_error, 0);
fae4b54f 1468 n_rcu_torture_barrier_error = 0;
8e8be45e
PM
1469 n_rcu_torture_boost_ktrerror = 0;
1470 n_rcu_torture_boost_rterror = 0;
8e8be45e
PM
1471 n_rcu_torture_boost_failure = 0;
1472 n_rcu_torture_boosts = 0;
a241ec65
PM
1473 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1474 atomic_set(&rcu_torture_wcount[i], 0);
0a945022 1475 for_each_possible_cpu(cpu) {
a241ec65
PM
1476 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1477 per_cpu(rcu_torture_count, cpu)[i] = 0;
1478 per_cpu(rcu_torture_batch, cpu)[i] = 0;
1479 }
1480 }
1481
1482 /* Start up the kthreads. */
1483
47cf29b9
PM
1484 firsterr = torture_create_kthread(rcu_torture_writer, NULL,
1485 writer_task);
1486 if (firsterr)
a241ec65 1487 goto unwind;
b772e1dd 1488 fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]),
a71fca58 1489 GFP_KERNEL);
b772e1dd 1490 if (fakewriter_tasks == NULL) {
5ccf60f2 1491 VERBOSE_TOROUT_ERRSTRING("out of memory");
b772e1dd
JT
1492 firsterr = -ENOMEM;
1493 goto unwind;
1494 }
1495 for (i = 0; i < nfakewriters; i++) {
47cf29b9
PM
1496 firsterr = torture_create_kthread(rcu_torture_fakewriter,
1497 NULL, fakewriter_tasks[i]);
1498 if (firsterr)
b772e1dd 1499 goto unwind;
b772e1dd 1500 }
2860aaba 1501 reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
a241ec65
PM
1502 GFP_KERNEL);
1503 if (reader_tasks == NULL) {
5ccf60f2 1504 VERBOSE_TOROUT_ERRSTRING("out of memory");
a241ec65
PM
1505 firsterr = -ENOMEM;
1506 goto unwind;
1507 }
1508 for (i = 0; i < nrealreaders; i++) {
47cf29b9
PM
1509 firsterr = torture_create_kthread(rcu_torture_reader, NULL,
1510 reader_tasks[i]);
1511 if (firsterr)
a241ec65 1512 goto unwind;
a241ec65
PM
1513 }
1514 if (stat_interval > 0) {
47cf29b9
PM
1515 firsterr = torture_create_kthread(rcu_torture_stats, NULL,
1516 stats_task);
1517 if (firsterr)
a241ec65 1518 goto unwind;
a241ec65 1519 }
d84f5203 1520 if (test_no_idle_hz) {
3808dc9f
PM
1521 firsterr = torture_shuffle_init(shuffle_interval * HZ);
1522 if (firsterr)
d84f5203 1523 goto unwind;
d84f5203 1524 }
d120f65f
PM
1525 if (stutter < 0)
1526 stutter = 0;
1527 if (stutter) {
628edaa5
PM
1528 firsterr = torture_stutter_init(stutter * HZ);
1529 if (firsterr)
d120f65f 1530 goto unwind;
d120f65f 1531 }
bf66f18e
PM
1532 if (fqs_duration < 0)
1533 fqs_duration = 0;
1534 if (fqs_duration) {
628edaa5 1535 /* Create the fqs thread */
47cf29b9
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1536 torture_create_kthread(rcu_torture_fqs, NULL, fqs_task);
1537 if (firsterr)
bf66f18e 1538 goto unwind;
bf66f18e 1539 }
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1540 if (test_boost_interval < 1)
1541 test_boost_interval = 1;
1542 if (test_boost_duration < 2)
1543 test_boost_duration = 2;
1544 if ((test_boost == 1 && cur_ops->can_boost) ||
1545 test_boost == 2) {
8e8be45e
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1546
1547 boost_starttime = jiffies + test_boost_interval * HZ;
1548 register_cpu_notifier(&rcutorture_cpu_nb);
1549 for_each_possible_cpu(i) {
1550 if (cpu_is_offline(i))
1551 continue; /* Heuristic: CPU can go offline. */
01025ebc
PM
1552 firsterr = rcutorture_booster_init(i);
1553 if (firsterr)
8e8be45e 1554 goto unwind;
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1555 }
1556 }
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1557 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
1558 if (firsterr)
37e377d2 1559 goto unwind;
01025ebc
PM
1560 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval * HZ);
1561 if (firsterr)
37e377d2 1562 goto unwind;
01025ebc
PM
1563 firsterr = rcu_torture_stall_init();
1564 if (firsterr)
37e377d2 1565 goto unwind;
01025ebc
PM
1566 firsterr = rcu_torture_barrier_init();
1567 if (firsterr)
fae4b54f 1568 goto unwind;
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1569 if (object_debug)
1570 rcu_test_debug_objects();
4a298656 1571 rcutorture_record_test_transition();
b5daa8f3 1572 torture_init_end();
a241ec65
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1573 return 0;
1574
1575unwind:
b5daa8f3 1576 torture_init_end();
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1577 rcu_torture_cleanup();
1578 return firsterr;
1579}
1580
1581module_init(rcu_torture_init);
1582module_exit(rcu_torture_cleanup);
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