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, you can access it online at 16 * http://www.gnu.org/licenses/gpl-2.0.html. 17 * 18 * Copyright (C) IBM Corporation, 2005, 2006 19 * 20 * Authors: Paul E. McKenney <paulmck@us.ibm.com> 21 * Josh Triplett <josh@freedesktop.org> 22 * 23 * See also: Documentation/RCU/torture.txt 24 */ 25 #include <linux/types.h> 26 #include <linux/kernel.h> 27 #include <linux/init.h> 28 #include <linux/module.h> 29 #include <linux/kthread.h> 30 #include <linux/err.h> 31 #include <linux/spinlock.h> 32 #include <linux/smp.h> 33 #include <linux/rcupdate.h> 34 #include <linux/interrupt.h> 35 #include <linux/sched.h> 36 #include <linux/atomic.h> 37 #include <linux/bitops.h> 38 #include <linux/completion.h> 39 #include <linux/moduleparam.h> 40 #include <linux/percpu.h> 41 #include <linux/notifier.h> 42 #include <linux/reboot.h> 43 #include <linux/freezer.h> 44 #include <linux/cpu.h> 45 #include <linux/delay.h> 46 #include <linux/stat.h> 47 #include <linux/srcu.h> 48 #include <linux/slab.h> 49 #include <linux/trace_clock.h> 50 #include <asm/byteorder.h> 51 #include <linux/torture.h> 52 53 MODULE_LICENSE("GPL"); 54 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@freedesktop.org>"); 55 56 57 torture_param(int, fqs_duration, 0, 58 "Duration of fqs bursts (us), 0 to disable"); 59 torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)"); 60 torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)"); 61 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives"); 62 torture_param(bool, gp_normal, false, 63 "Use normal (non-expedited) GP wait primitives"); 64 torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers"); 65 torture_param(int, n_barrier_cbs, 0, 66 "# of callbacks/kthreads for barrier testing"); 67 torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads"); 68 torture_param(int, nreaders, -1, "Number of RCU reader threads"); 69 torture_param(int, object_debug, 0, 70 "Enable debug-object double call_rcu() testing"); 71 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)"); 72 torture_param(int, onoff_interval, 0, 73 "Time between CPU hotplugs (s), 0=disable"); 74 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles"); 75 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable."); 76 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable."); 77 torture_param(int, stall_cpu_holdoff, 10, 78 "Time to wait before starting stall (s)."); 79 torture_param(int, stat_interval, 60, 80 "Number of seconds between stats printk()s"); 81 torture_param(int, stutter, 5, "Number of seconds to run/halt test"); 82 torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes."); 83 torture_param(int, test_boost_duration, 4, 84 "Duration of each boost test, seconds."); 85 torture_param(int, test_boost_interval, 7, 86 "Interval between boost tests, seconds."); 87 torture_param(bool, test_no_idle_hz, true, 88 "Test support for tickless idle CPUs"); 89 torture_param(bool, verbose, true, 90 "Enable verbose debugging printk()s"); 91 92 static char *torture_type = "rcu"; 93 module_param(torture_type, charp, 0444); 94 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, ...)"); 95 96 static int nrealreaders; 97 static struct task_struct *writer_task; 98 static struct task_struct **fakewriter_tasks; 99 static struct task_struct **reader_tasks; 100 static struct task_struct *stats_task; 101 static struct task_struct *fqs_task; 102 static struct task_struct *boost_tasks[NR_CPUS]; 103 static struct task_struct *stall_task; 104 static struct task_struct **barrier_cbs_tasks; 105 static struct task_struct *barrier_task; 106 107 #define RCU_TORTURE_PIPE_LEN 10 108 109 struct rcu_torture { 110 struct rcu_head rtort_rcu; 111 int rtort_pipe_count; 112 struct list_head rtort_free; 113 int rtort_mbtest; 114 }; 115 116 static LIST_HEAD(rcu_torture_freelist); 117 static struct rcu_torture __rcu *rcu_torture_current; 118 static unsigned long rcu_torture_current_version; 119 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN]; 120 static DEFINE_SPINLOCK(rcu_torture_lock); 121 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], 122 rcu_torture_count) = { 0 }; 123 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], 124 rcu_torture_batch) = { 0 }; 125 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1]; 126 static atomic_t n_rcu_torture_alloc; 127 static atomic_t n_rcu_torture_alloc_fail; 128 static atomic_t n_rcu_torture_free; 129 static atomic_t n_rcu_torture_mberror; 130 static atomic_t n_rcu_torture_error; 131 static long n_rcu_torture_barrier_error; 132 static long n_rcu_torture_boost_ktrerror; 133 static long n_rcu_torture_boost_rterror; 134 static long n_rcu_torture_boost_failure; 135 static long n_rcu_torture_boosts; 136 static long n_rcu_torture_timers; 137 static long n_barrier_attempts; 138 static long n_barrier_successes; 139 static struct list_head rcu_torture_removed; 140 141 #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 146 int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT; 147 module_param(rcutorture_runnable, int, 0444); 148 MODULE_PARM_DESC(rcutorture_runnable, "Start rcutorture at boot"); 149 150 #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) 151 #define rcu_can_boost() 1 152 #else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */ 153 #define rcu_can_boost() 0 154 #endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */ 155 156 #ifdef CONFIG_RCU_TRACE 157 static 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 */ 164 static u64 notrace rcu_trace_clock_local(void) 165 { 166 return 0ULL; 167 } 168 #endif /* #else #ifdef CONFIG_RCU_TRACE */ 169 170 static unsigned long boost_starttime; /* jiffies of next boost test start. */ 171 DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */ 172 /* and boost task create/destroy. */ 173 static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */ 174 static bool barrier_phase; /* Test phase. */ 175 static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */ 176 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */ 177 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq); 178 179 /* 180 * Allocate an element from the rcu_tortures pool. 181 */ 182 static struct rcu_torture * 183 rcu_torture_alloc(void) 184 { 185 struct list_head *p; 186 187 spin_lock_bh(&rcu_torture_lock); 188 if (list_empty(&rcu_torture_freelist)) { 189 atomic_inc(&n_rcu_torture_alloc_fail); 190 spin_unlock_bh(&rcu_torture_lock); 191 return NULL; 192 } 193 atomic_inc(&n_rcu_torture_alloc); 194 p = rcu_torture_freelist.next; 195 list_del_init(p); 196 spin_unlock_bh(&rcu_torture_lock); 197 return container_of(p, struct rcu_torture, rtort_free); 198 } 199 200 /* 201 * Free an element to the rcu_tortures pool. 202 */ 203 static void 204 rcu_torture_free(struct rcu_torture *p) 205 { 206 atomic_inc(&n_rcu_torture_free); 207 spin_lock_bh(&rcu_torture_lock); 208 list_add_tail(&p->rtort_free, &rcu_torture_freelist); 209 spin_unlock_bh(&rcu_torture_lock); 210 } 211 212 /* 213 * Operations vector for selecting different types of tests. 214 */ 215 216 struct rcu_torture_ops { 217 void (*init)(void); 218 int (*readlock)(void); 219 void (*read_delay)(struct torture_random_state *rrsp); 220 void (*readunlock)(int idx); 221 int (*completed)(void); 222 void (*deferred_free)(struct rcu_torture *p); 223 void (*sync)(void); 224 void (*exp_sync)(void); 225 void (*call)(struct rcu_head *head, void (*func)(struct rcu_head *rcu)); 226 void (*cb_barrier)(void); 227 void (*fqs)(void); 228 void (*stats)(char *page); 229 int irq_capable; 230 int can_boost; 231 const char *name; 232 }; 233 234 static struct rcu_torture_ops *cur_ops; 235 236 /* 237 * Definitions for rcu torture testing. 238 */ 239 240 static int rcu_torture_read_lock(void) __acquires(RCU) 241 { 242 rcu_read_lock(); 243 return 0; 244 } 245 246 static void rcu_read_delay(struct torture_random_state *rrsp) 247 { 248 const unsigned long shortdelay_us = 200; 249 const unsigned long longdelay_ms = 50; 250 251 /* 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. */ 254 255 if (!(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) 256 mdelay(longdelay_ms); 257 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) 258 udelay(shortdelay_us); 259 #ifdef CONFIG_PREEMPT 260 if (!preempt_count() && 261 !(torture_random(rrsp) % (nrealreaders * 20000))) 262 preempt_schedule(); /* No QS if preempt_disable() in effect */ 263 #endif 264 } 265 266 static void rcu_torture_read_unlock(int idx) __releases(RCU) 267 { 268 rcu_read_unlock(); 269 } 270 271 static int rcu_torture_completed(void) 272 { 273 return rcu_batches_completed(); 274 } 275 276 static void 277 rcu_torture_cb(struct rcu_head *p) 278 { 279 int i; 280 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu); 281 282 if (torture_must_stop_irq()) { 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); 294 } else { 295 cur_ops->deferred_free(rp); 296 } 297 } 298 299 static int rcu_no_completed(void) 300 { 301 return 0; 302 } 303 304 static void rcu_torture_deferred_free(struct rcu_torture *p) 305 { 306 call_rcu(&p->rtort_rcu, rcu_torture_cb); 307 } 308 309 static void rcu_sync_torture_init(void) 310 { 311 INIT_LIST_HEAD(&rcu_torture_removed); 312 } 313 314 static struct rcu_torture_ops rcu_ops = { 315 .init = rcu_sync_torture_init, 316 .readlock = rcu_torture_read_lock, 317 .read_delay = rcu_read_delay, 318 .readunlock = rcu_torture_read_unlock, 319 .completed = rcu_torture_completed, 320 .deferred_free = rcu_torture_deferred_free, 321 .sync = synchronize_rcu, 322 .exp_sync = synchronize_rcu_expedited, 323 .call = call_rcu, 324 .cb_barrier = rcu_barrier, 325 .fqs = rcu_force_quiescent_state, 326 .stats = NULL, 327 .irq_capable = 1, 328 .can_boost = rcu_can_boost(), 329 .name = "rcu" 330 }; 331 332 /* 333 * Definitions for rcu_bh torture testing. 334 */ 335 336 static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH) 337 { 338 rcu_read_lock_bh(); 339 return 0; 340 } 341 342 static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH) 343 { 344 rcu_read_unlock_bh(); 345 } 346 347 static int rcu_bh_torture_completed(void) 348 { 349 return rcu_batches_completed_bh(); 350 } 351 352 static void rcu_bh_torture_deferred_free(struct rcu_torture *p) 353 { 354 call_rcu_bh(&p->rtort_rcu, rcu_torture_cb); 355 } 356 357 static struct rcu_torture_ops rcu_bh_ops = { 358 .init = rcu_sync_torture_init, 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, 364 .sync = synchronize_rcu_bh, 365 .exp_sync = synchronize_rcu_bh_expedited, 366 .call = call_rcu_bh, 367 .cb_barrier = rcu_barrier_bh, 368 .fqs = rcu_bh_force_quiescent_state, 369 .stats = NULL, 370 .irq_capable = 1, 371 .name = "rcu_bh" 372 }; 373 374 /* 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 */ 381 static 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 } 386 387 static void synchronize_rcu_busted(void) 388 { 389 /* This is a deliberate bug for testing purposes only! */ 390 } 391 392 static void 393 call_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 } 398 399 static 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 }; 415 416 /* 417 * Definitions for srcu torture testing. 418 */ 419 420 DEFINE_STATIC_SRCU(srcu_ctl); 421 422 static int srcu_torture_read_lock(void) __acquires(&srcu_ctl) 423 { 424 return srcu_read_lock(&srcu_ctl); 425 } 426 427 static void srcu_read_delay(struct torture_random_state *rrsp) 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. */ 434 435 delay = torture_random(rrsp) % 436 (nrealreaders * 2 * longdelay * uspertick); 437 if (!delay) 438 schedule_timeout_interruptible(longdelay); 439 else 440 rcu_read_delay(rrsp); 441 } 442 443 static void srcu_torture_read_unlock(int idx) __releases(&srcu_ctl) 444 { 445 srcu_read_unlock(&srcu_ctl, idx); 446 } 447 448 static int srcu_torture_completed(void) 449 { 450 return srcu_batches_completed(&srcu_ctl); 451 } 452 453 static void srcu_torture_deferred_free(struct rcu_torture *rp) 454 { 455 call_srcu(&srcu_ctl, &rp->rtort_rcu, rcu_torture_cb); 456 } 457 458 static void srcu_torture_synchronize(void) 459 { 460 synchronize_srcu(&srcu_ctl); 461 } 462 463 static void srcu_torture_call(struct rcu_head *head, 464 void (*func)(struct rcu_head *head)) 465 { 466 call_srcu(&srcu_ctl, head, func); 467 } 468 469 static void srcu_torture_barrier(void) 470 { 471 srcu_barrier(&srcu_ctl); 472 } 473 474 static void srcu_torture_stats(char *page) 475 { 476 int cpu; 477 int idx = srcu_ctl.completed & 0x1; 478 479 page += sprintf(page, "%s%s per-CPU(idx=%d):", 480 torture_type, TORTURE_FLAG, idx); 481 for_each_possible_cpu(cpu) { 482 page += sprintf(page, " %d(%lu,%lu)", cpu, 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 } 486 sprintf(page, "\n"); 487 } 488 489 static void srcu_torture_synchronize_expedited(void) 490 { 491 synchronize_srcu_expedited(&srcu_ctl); 492 } 493 494 static struct rcu_torture_ops srcu_ops = { 495 .init = rcu_sync_torture_init, 496 .readlock = srcu_torture_read_lock, 497 .read_delay = srcu_read_delay, 498 .readunlock = srcu_torture_read_unlock, 499 .completed = srcu_torture_completed, 500 .deferred_free = srcu_torture_deferred_free, 501 .sync = srcu_torture_synchronize, 502 .exp_sync = srcu_torture_synchronize_expedited, 503 .call = srcu_torture_call, 504 .cb_barrier = srcu_torture_barrier, 505 .stats = srcu_torture_stats, 506 .name = "srcu" 507 }; 508 509 /* 510 * Definitions for sched torture testing. 511 */ 512 513 static int sched_torture_read_lock(void) 514 { 515 preempt_disable(); 516 return 0; 517 } 518 519 static void sched_torture_read_unlock(int idx) 520 { 521 preempt_enable(); 522 } 523 524 static void rcu_sched_torture_deferred_free(struct rcu_torture *p) 525 { 526 call_rcu_sched(&p->rtort_rcu, rcu_torture_cb); 527 } 528 529 static struct rcu_torture_ops sched_ops = { 530 .init = rcu_sync_torture_init, 531 .readlock = sched_torture_read_lock, 532 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 533 .readunlock = sched_torture_read_unlock, 534 .completed = rcu_no_completed, 535 .deferred_free = rcu_sched_torture_deferred_free, 536 .sync = synchronize_sched, 537 .exp_sync = synchronize_sched_expedited, 538 .call = call_rcu_sched, 539 .cb_barrier = rcu_barrier_sched, 540 .fqs = rcu_sched_force_quiescent_state, 541 .stats = NULL, 542 .irq_capable = 1, 543 .name = "sched" 544 }; 545 546 /* 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 */ 552 553 struct rcu_boost_inflight { 554 struct rcu_head rcu; 555 int inflight; 556 }; 557 558 static 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 } 566 567 static 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; 574 575 VERBOSE_TOROUT_STRING("rcu_torture_boost started"); 576 577 /* Set real-time priority. */ 578 sp.sched_priority = 1; 579 if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) { 580 VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!"); 581 n_rcu_torture_boost_rterror++; 582 } 583 584 init_rcu_head_on_stack(&rbi.rcu); 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; 589 while (ULONG_CMP_LT(jiffies, oldstarttime)) { 590 schedule_timeout_interruptible(oldstarttime - jiffies); 591 stutter_wait("rcu_torture_boost"); 592 if (torture_must_stop()) 593 goto checkwait; 594 } 595 596 /* Do one boost-test interval. */ 597 endtime = oldstarttime + test_boost_duration * HZ; 598 call_rcu_time = jiffies; 599 while (ULONG_CMP_LT(jiffies, endtime)) { 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) { 607 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed"); 608 n_rcu_torture_boost_failure++; 609 } 610 call_rcu_time = jiffies; 611 } 612 cond_resched(); 613 stutter_wait("rcu_torture_boost"); 614 if (torture_must_stop()) 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 */ 625 while (oldstarttime == boost_starttime && 626 !kthread_should_stop()) { 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. */ 638 checkwait: stutter_wait("rcu_torture_boost"); 639 } while (!torture_must_stop()); 640 641 /* Clean up and exit. */ 642 while (!kthread_should_stop() || rbi.inflight) { 643 torture_shutdown_absorb("rcu_torture_boost"); 644 schedule_timeout_uninterruptible(1); 645 } 646 smp_mb(); /* order accesses to ->inflight before stack-frame death. */ 647 destroy_rcu_head_on_stack(&rbi.rcu); 648 torture_kthread_stopping("rcu_torture_boost"); 649 return 0; 650 } 651 652 /* 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 */ 657 static int 658 rcu_torture_fqs(void *arg) 659 { 660 unsigned long fqs_resume_time; 661 int fqs_burst_remaining; 662 663 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started"); 664 do { 665 fqs_resume_time = jiffies + fqs_stutter * HZ; 666 while (ULONG_CMP_LT(jiffies, fqs_resume_time) && 667 !kthread_should_stop()) { 668 schedule_timeout_interruptible(1); 669 } 670 fqs_burst_remaining = fqs_duration; 671 while (fqs_burst_remaining > 0 && 672 !kthread_should_stop()) { 673 cur_ops->fqs(); 674 udelay(fqs_holdoff); 675 fqs_burst_remaining -= fqs_holdoff; 676 } 677 stutter_wait("rcu_torture_fqs"); 678 } while (!torture_must_stop()); 679 torture_kthread_stopping("rcu_torture_fqs"); 680 return 0; 681 } 682 683 /* 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 */ 688 static int 689 rcu_torture_writer(void *arg) 690 { 691 bool exp; 692 int i; 693 struct rcu_torture *rp; 694 struct rcu_torture *rp1; 695 struct rcu_torture *old_rp; 696 static DEFINE_TORTURE_RANDOM(rand); 697 698 VERBOSE_TOROUT_STRING("rcu_torture_writer task started"); 699 set_user_nice(current, MAX_NICE); 700 701 do { 702 schedule_timeout_uninterruptible(1); 703 rp = rcu_torture_alloc(); 704 if (rp == NULL) 705 continue; 706 rp->rtort_pipe_count = 0; 707 udelay(torture_random(&rand) & 0x3ff); 708 old_rp = rcu_dereference_check(rcu_torture_current, 709 current == writer_task); 710 rp->rtort_mbtest = 1; 711 rcu_assign_pointer(rcu_torture_current, rp); 712 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */ 713 if (old_rp) { 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++; 719 if (gp_normal == gp_exp) 720 exp = !!(torture_random(&rand) & 0x80); 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 } 744 } 745 rcutorture_record_progress(++rcu_torture_current_version); 746 stutter_wait("rcu_torture_writer"); 747 } while (!torture_must_stop()); 748 torture_kthread_stopping("rcu_torture_writer"); 749 return 0; 750 } 751 752 /* 753 * RCU torture fake writer kthread. Repeatedly calls sync, with a random 754 * delay between calls. 755 */ 756 static int 757 rcu_torture_fakewriter(void *arg) 758 { 759 DEFINE_TORTURE_RANDOM(rand); 760 761 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started"); 762 set_user_nice(current, MAX_NICE); 763 764 do { 765 schedule_timeout_uninterruptible(1 + torture_random(&rand)%10); 766 udelay(torture_random(&rand) & 0x3ff); 767 if (cur_ops->cb_barrier != NULL && 768 torture_random(&rand) % (nfakewriters * 8) == 0) { 769 cur_ops->cb_barrier(); 770 } else if (gp_normal == gp_exp) { 771 if (torture_random(&rand) & 0x80) 772 cur_ops->sync(); 773 else 774 cur_ops->exp_sync(); 775 } else if (gp_normal) { 776 cur_ops->sync(); 777 } else { 778 cur_ops->exp_sync(); 779 } 780 stutter_wait("rcu_torture_fakewriter"); 781 } while (!torture_must_stop()); 782 783 torture_kthread_stopping("rcu_torture_fakewriter"); 784 return 0; 785 } 786 787 void 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; 795 ftrace_dump(DUMP_ALL); 796 } 797 798 /* 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 */ 804 static void rcu_torture_timer(unsigned long unused) 805 { 806 int idx; 807 int completed; 808 int completed_end; 809 static DEFINE_TORTURE_RANDOM(rand); 810 static DEFINE_SPINLOCK(rand_lock); 811 struct rcu_torture *p; 812 int pipe_count; 813 unsigned long long ts; 814 815 idx = cur_ops->readlock(); 816 completed = cur_ops->completed(); 817 ts = rcu_trace_clock_local(); 818 p = rcu_dereference_check(rcu_torture_current, 819 rcu_read_lock_bh_held() || 820 rcu_read_lock_sched_held() || 821 srcu_read_lock_held(&srcu_ctl)); 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); 830 cur_ops->read_delay(&rand); 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 } 839 completed_end = cur_ops->completed(); 840 if (pipe_count > 1) { 841 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, ts, 842 completed, completed_end); 843 rcutorture_trace_dump(); 844 } 845 __this_cpu_inc(rcu_torture_count[pipe_count]); 846 completed = completed_end - completed; 847 if (completed > RCU_TORTURE_PIPE_LEN) { 848 /* Should not happen, but... */ 849 completed = RCU_TORTURE_PIPE_LEN; 850 } 851 __this_cpu_inc(rcu_torture_batch[completed]); 852 preempt_enable(); 853 cur_ops->readunlock(idx); 854 } 855 856 /* 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 */ 862 static int 863 rcu_torture_reader(void *arg) 864 { 865 int completed; 866 int completed_end; 867 int idx; 868 DEFINE_TORTURE_RANDOM(rand); 869 struct rcu_torture *p; 870 int pipe_count; 871 struct timer_list t; 872 unsigned long long ts; 873 874 VERBOSE_TOROUT_STRING("rcu_torture_reader task started"); 875 set_user_nice(current, MAX_NICE); 876 if (irqreader && cur_ops->irq_capable) 877 setup_timer_on_stack(&t, rcu_torture_timer, 0); 878 879 do { 880 if (irqreader && cur_ops->irq_capable) { 881 if (!timer_pending(&t)) 882 mod_timer(&t, jiffies + 1); 883 } 884 idx = cur_ops->readlock(); 885 completed = cur_ops->completed(); 886 ts = rcu_trace_clock_local(); 887 p = rcu_dereference_check(rcu_torture_current, 888 rcu_read_lock_bh_held() || 889 rcu_read_lock_sched_held() || 890 srcu_read_lock_held(&srcu_ctl)); 891 if (p == NULL) { 892 /* Wait for rcu_torture_writer to get underway */ 893 cur_ops->readunlock(idx); 894 schedule_timeout_interruptible(HZ); 895 continue; 896 } 897 if (p->rtort_mbtest == 0) 898 atomic_inc(&n_rcu_torture_mberror); 899 cur_ops->read_delay(&rand); 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 } 906 completed_end = cur_ops->completed(); 907 if (pipe_count > 1) { 908 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, 909 ts, completed, completed_end); 910 rcutorture_trace_dump(); 911 } 912 __this_cpu_inc(rcu_torture_count[pipe_count]); 913 completed = completed_end - completed; 914 if (completed > RCU_TORTURE_PIPE_LEN) { 915 /* Should not happen, but... */ 916 completed = RCU_TORTURE_PIPE_LEN; 917 } 918 __this_cpu_inc(rcu_torture_batch[completed]); 919 preempt_enable(); 920 cur_ops->readunlock(idx); 921 schedule(); 922 stutter_wait("rcu_torture_reader"); 923 } while (!torture_must_stop()); 924 if (irqreader && cur_ops->irq_capable) 925 del_timer_sync(&t); 926 torture_kthread_stopping("rcu_torture_reader"); 927 return 0; 928 } 929 930 /* 931 * Create an RCU-torture statistics message in the specified buffer. 932 */ 933 static void 934 rcu_torture_printk(char *page) 935 { 936 int cpu; 937 int i; 938 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; 939 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; 940 941 for_each_possible_cpu(cpu) { 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 } 951 page += sprintf(page, "%s%s ", torture_type, TORTURE_FLAG); 952 page += sprintf(page, 953 "rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ", 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), 959 atomic_read(&n_rcu_torture_free)); 960 page += sprintf(page, "rtmbe: %d rtbke: %ld rtbre: %ld ", 961 atomic_read(&n_rcu_torture_mberror), 962 n_rcu_torture_boost_ktrerror, 963 n_rcu_torture_boost_rterror); 964 page += sprintf(page, "rtbf: %ld rtb: %ld nt: %ld ", 965 n_rcu_torture_boost_failure, 966 n_rcu_torture_boosts, 967 n_rcu_torture_timers); 968 page = torture_onoff_stats(page); 969 page += sprintf(page, "barrier: %ld/%ld:%ld", 970 n_barrier_successes, 971 n_barrier_attempts, 972 n_rcu_torture_barrier_error); 973 page += sprintf(page, "\n%s%s ", torture_type, TORTURE_FLAG); 974 if (atomic_read(&n_rcu_torture_mberror) != 0 || 975 n_rcu_torture_barrier_error != 0 || 976 n_rcu_torture_boost_ktrerror != 0 || 977 n_rcu_torture_boost_rterror != 0 || 978 n_rcu_torture_boost_failure != 0 || 979 i > 1) { 980 page += sprintf(page, "!!! "); 981 atomic_inc(&n_rcu_torture_error); 982 WARN_ON_ONCE(1); 983 } 984 page += sprintf(page, "Reader Pipe: "); 985 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 986 page += sprintf(page, " %ld", pipesummary[i]); 987 page += sprintf(page, "\n%s%s ", torture_type, TORTURE_FLAG); 988 page += sprintf(page, "Reader Batch: "); 989 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 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: "); 993 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 994 page += sprintf(page, " %d", 995 atomic_read(&rcu_torture_wcount[i])); 996 } 997 page += sprintf(page, "\n"); 998 if (cur_ops->stats) 999 cur_ops->stats(page); 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 */ 1010 static void 1011 rcu_torture_stats_print(void) 1012 { 1013 int size = nr_cpu_ids * 200 + 8192; 1014 char *buf; 1015 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); 1024 } 1025 1026 /* 1027 * Periodically prints torture statistics, if periodic statistics printing 1028 * was specified via the stat_interval module parameter. 1029 */ 1030 static int 1031 rcu_torture_stats(void *arg) 1032 { 1033 VERBOSE_TOROUT_STRING("rcu_torture_stats task started"); 1034 do { 1035 schedule_timeout_interruptible(stat_interval * HZ); 1036 rcu_torture_stats_print(); 1037 torture_shutdown_absorb("rcu_torture_stats"); 1038 } while (!torture_must_stop()); 1039 torture_kthread_stopping("rcu_torture_stats"); 1040 return 0; 1041 } 1042 1043 static inline void 1044 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag) 1045 { 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 " 1053 "stall_cpu=%d stall_cpu_holdoff=%d " 1054 "n_barrier_cbs=%d " 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, 1061 stall_cpu, stall_cpu_holdoff, 1062 n_barrier_cbs, 1063 onoff_interval, onoff_holdoff); 1064 } 1065 1066 static 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); 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! */ 1078 torture_stop_kthread(rcu_torture_boost, t); 1079 } 1080 1081 static 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); 1090 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task"); 1091 boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL, 1092 cpu_to_node(cpu), 1093 "rcu_torture_boost"); 1094 if (IS_ERR(boost_tasks[cpu])) { 1095 retval = PTR_ERR(boost_tasks[cpu]); 1096 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed"); 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 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 */ 1112 static int rcu_torture_stall(void *args) 1113 { 1114 unsigned long stop_at; 1115 1116 VERBOSE_TOROUT_STRING("rcu_torture_stall task started"); 1117 if (stall_cpu_holdoff > 0) { 1118 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff"); 1119 schedule_timeout_interruptible(stall_cpu_holdoff * HZ); 1120 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff"); 1121 } 1122 if (!kthread_should_stop()) { 1123 stop_at = get_seconds() + stall_cpu; 1124 /* RCU CPU stall is expected behavior in following code. */ 1125 pr_alert("rcu_torture_stall start.\n"); 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(); 1132 pr_alert("rcu_torture_stall end.\n"); 1133 } 1134 torture_shutdown_absorb("rcu_torture_stall"); 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. */ 1141 static int __init rcu_torture_stall_init(void) 1142 { 1143 if (stall_cpu <= 0) 1144 return 0; 1145 return torture_create_kthread(rcu_torture_stall, NULL, stall_task); 1146 } 1147 1148 /* Callback function for RCU barrier testing. */ 1149 void 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. */ 1155 static int rcu_torture_barrier_cbs(void *arg) 1156 { 1157 long myid = (long)arg; 1158 bool lastphase = 0; 1159 bool newphase; 1160 struct rcu_head rcu; 1161 1162 init_rcu_head_on_stack(&rcu); 1163 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started"); 1164 set_user_nice(current, MAX_NICE); 1165 do { 1166 wait_event(barrier_cbs_wq[myid], 1167 (newphase = 1168 ACCESS_ONCE(barrier_phase)) != lastphase || 1169 torture_must_stop()); 1170 lastphase = newphase; 1171 smp_mb(); /* ensure barrier_phase load before ->call(). */ 1172 if (torture_must_stop()) 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); 1177 } while (!torture_must_stop()); 1178 cur_ops->cb_barrier(); 1179 destroy_rcu_head_on_stack(&rcu); 1180 torture_kthread_stopping("rcu_torture_barrier_cbs"); 1181 return 0; 1182 } 1183 1184 /* kthread function to drive and coordinate RCU barrier testing. */ 1185 static int rcu_torture_barrier(void *arg) 1186 { 1187 int i; 1188 1189 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting"); 1190 do { 1191 atomic_set(&barrier_cbs_invoked, 0); 1192 atomic_set(&barrier_cbs_count, n_barrier_cbs); 1193 smp_mb(); /* Ensure barrier_phase after prior assignments. */ 1194 barrier_phase = !barrier_phase; 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 || 1199 torture_must_stop()); 1200 if (torture_must_stop()) 1201 break; 1202 n_barrier_attempts++; 1203 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */ 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); 1210 } while (!torture_must_stop()); 1211 torture_kthread_stopping("rcu_torture_barrier"); 1212 return 0; 1213 } 1214 1215 /* Initialize RCU barrier testing. */ 1216 static 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) { 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); 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); 1240 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq) 1241 return -ENOMEM; 1242 for (i = 0; i < n_barrier_cbs; i++) { 1243 init_waitqueue_head(&barrier_cbs_wq[i]); 1244 ret = torture_create_kthread(rcu_torture_barrier_cbs, 1245 (void *)(long)i, 1246 barrier_cbs_tasks[i]); 1247 if (ret) 1248 return ret; 1249 } 1250 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task); 1251 } 1252 1253 /* Clean up after RCU barrier testing. */ 1254 static void rcu_torture_barrier_cleanup(void) 1255 { 1256 int i; 1257 1258 torture_stop_kthread(rcu_torture_barrier, barrier_task); 1259 if (barrier_cbs_tasks != NULL) { 1260 for (i = 0; i < n_barrier_cbs; i++) 1261 torture_stop_kthread(rcu_torture_barrier_cbs, 1262 barrier_cbs_tasks[i]); 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 1272 static 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 1291 static struct notifier_block rcutorture_cpu_nb = { 1292 .notifier_call = rcutorture_cpu_notify, 1293 }; 1294 1295 static void 1296 rcu_torture_cleanup(void) 1297 { 1298 int i; 1299 1300 rcutorture_record_test_transition(); 1301 if (torture_cleanup()) { 1302 if (cur_ops->cb_barrier != NULL) 1303 cur_ops->cb_barrier(); 1304 return; 1305 } 1306 1307 rcu_torture_barrier_cleanup(); 1308 torture_stop_kthread(rcu_torture_stall, stall_task); 1309 torture_stop_kthread(rcu_torture_writer, writer_task); 1310 1311 if (reader_tasks) { 1312 for (i = 0; i < nrealreaders; i++) 1313 torture_stop_kthread(rcu_torture_reader, 1314 reader_tasks[i]); 1315 kfree(reader_tasks); 1316 } 1317 rcu_torture_current = NULL; 1318 1319 if (fakewriter_tasks) { 1320 for (i = 0; i < nfakewriters; i++) { 1321 torture_stop_kthread(rcu_torture_fakewriter, 1322 fakewriter_tasks[i]); 1323 } 1324 kfree(fakewriter_tasks); 1325 fakewriter_tasks = NULL; 1326 } 1327 1328 torture_stop_kthread(rcu_torture_stats, stats_task); 1329 torture_stop_kthread(rcu_torture_fqs, fqs_task); 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 } 1336 1337 /* Wait for all RCU callbacks to fire. */ 1338 1339 if (cur_ops->cb_barrier != NULL) 1340 cur_ops->cb_barrier(); 1341 1342 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */ 1343 1344 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error) 1345 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE"); 1346 else if (torture_onoff_failures()) 1347 rcu_torture_print_module_parms(cur_ops, 1348 "End of test: RCU_HOTPLUG"); 1349 else 1350 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS"); 1351 } 1352 1353 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD 1354 static void rcu_torture_leak_cb(struct rcu_head *rhp) 1355 { 1356 } 1357 1358 static 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 */ 1378 static 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 1409 static int __init 1410 rcu_torture_init(void) 1411 { 1412 int i; 1413 int cpu; 1414 int firsterr = 0; 1415 static struct rcu_torture_ops *torture_ops[] = { 1416 &rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &sched_ops, 1417 }; 1418 1419 torture_init_begin(torture_type, verbose, &rcutorture_runnable); 1420 1421 /* Process args and tell the world that the torturer is on the job. */ 1422 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) { 1423 cur_ops = torture_ops[i]; 1424 if (strcmp(torture_type, cur_ops->name) == 0) 1425 break; 1426 } 1427 if (i == ARRAY_SIZE(torture_ops)) { 1428 pr_alert("rcu-torture: invalid torture type: \"%s\"\n", 1429 torture_type); 1430 pr_alert("rcu-torture types:"); 1431 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) 1432 pr_alert(" %s", torture_ops[i]->name); 1433 pr_alert("\n"); 1434 torture_init_end(); 1435 return -EINVAL; 1436 } 1437 if (cur_ops->fqs == NULL && fqs_duration != 0) { 1438 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n"); 1439 fqs_duration = 0; 1440 } 1441 if (cur_ops->init) 1442 cur_ops->init(); /* no "goto unwind" prior to this point!!! */ 1443 1444 if (nreaders >= 0) 1445 nrealreaders = nreaders; 1446 else 1447 nrealreaders = 2 * num_online_cpus(); 1448 rcu_torture_print_module_parms(cur_ops, "Start of test"); 1449 1450 /* Set up the freelist. */ 1451 1452 INIT_LIST_HEAD(&rcu_torture_freelist); 1453 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) { 1454 rcu_tortures[i].rtort_mbtest = 0; 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); 1466 atomic_set(&n_rcu_torture_mberror, 0); 1467 atomic_set(&n_rcu_torture_error, 0); 1468 n_rcu_torture_barrier_error = 0; 1469 n_rcu_torture_boost_ktrerror = 0; 1470 n_rcu_torture_boost_rterror = 0; 1471 n_rcu_torture_boost_failure = 0; 1472 n_rcu_torture_boosts = 0; 1473 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 1474 atomic_set(&rcu_torture_wcount[i], 0); 1475 for_each_possible_cpu(cpu) { 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 1484 firsterr = torture_create_kthread(rcu_torture_writer, NULL, 1485 writer_task); 1486 if (firsterr) 1487 goto unwind; 1488 fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]), 1489 GFP_KERNEL); 1490 if (fakewriter_tasks == NULL) { 1491 VERBOSE_TOROUT_ERRSTRING("out of memory"); 1492 firsterr = -ENOMEM; 1493 goto unwind; 1494 } 1495 for (i = 0; i < nfakewriters; i++) { 1496 firsterr = torture_create_kthread(rcu_torture_fakewriter, 1497 NULL, fakewriter_tasks[i]); 1498 if (firsterr) 1499 goto unwind; 1500 } 1501 reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]), 1502 GFP_KERNEL); 1503 if (reader_tasks == NULL) { 1504 VERBOSE_TOROUT_ERRSTRING("out of memory"); 1505 firsterr = -ENOMEM; 1506 goto unwind; 1507 } 1508 for (i = 0; i < nrealreaders; i++) { 1509 firsterr = torture_create_kthread(rcu_torture_reader, NULL, 1510 reader_tasks[i]); 1511 if (firsterr) 1512 goto unwind; 1513 } 1514 if (stat_interval > 0) { 1515 firsterr = torture_create_kthread(rcu_torture_stats, NULL, 1516 stats_task); 1517 if (firsterr) 1518 goto unwind; 1519 } 1520 if (test_no_idle_hz) { 1521 firsterr = torture_shuffle_init(shuffle_interval * HZ); 1522 if (firsterr) 1523 goto unwind; 1524 } 1525 if (stutter < 0) 1526 stutter = 0; 1527 if (stutter) { 1528 firsterr = torture_stutter_init(stutter * HZ); 1529 if (firsterr) 1530 goto unwind; 1531 } 1532 if (fqs_duration < 0) 1533 fqs_duration = 0; 1534 if (fqs_duration) { 1535 /* Create the fqs thread */ 1536 torture_create_kthread(rcu_torture_fqs, NULL, fqs_task); 1537 if (firsterr) 1538 goto unwind; 1539 } 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) { 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. */ 1552 firsterr = rcutorture_booster_init(i); 1553 if (firsterr) 1554 goto unwind; 1555 } 1556 } 1557 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup); 1558 if (firsterr) 1559 goto unwind; 1560 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval * HZ); 1561 if (firsterr) 1562 goto unwind; 1563 firsterr = rcu_torture_stall_init(); 1564 if (firsterr) 1565 goto unwind; 1566 firsterr = rcu_torture_barrier_init(); 1567 if (firsterr) 1568 goto unwind; 1569 if (object_debug) 1570 rcu_test_debug_objects(); 1571 rcutorture_record_test_transition(); 1572 torture_init_end(); 1573 return 0; 1574 1575 unwind: 1576 torture_init_end(); 1577 rcu_torture_cleanup(); 1578 return firsterr; 1579 } 1580 1581 module_init(rcu_torture_init); 1582 module_exit(rcu_torture_cleanup); 1583