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@joshtriplett.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#include <linux/vmalloc.h> 53 54MODULE_LICENSE("GPL"); 55MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@joshtriplett.org>"); 56 57 58torture_param(int, cbflood_inter_holdoff, HZ, 59 "Holdoff between floods (jiffies)"); 60torture_param(int, cbflood_intra_holdoff, 1, 61 "Holdoff between bursts (jiffies)"); 62torture_param(int, cbflood_n_burst, 3, "# bursts in flood, zero to disable"); 63torture_param(int, cbflood_n_per_burst, 20000, 64 "# callbacks per burst in flood"); 65torture_param(int, fqs_duration, 0, 66 "Duration of fqs bursts (us), 0 to disable"); 67torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)"); 68torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)"); 69torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives"); 70torture_param(bool, gp_exp, false, "Use expedited GP wait primitives"); 71torture_param(bool, gp_normal, false, 72 "Use normal (non-expedited) GP wait primitives"); 73torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives"); 74torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers"); 75torture_param(int, n_barrier_cbs, 0, 76 "# of callbacks/kthreads for barrier testing"); 77torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads"); 78torture_param(int, nreaders, -1, "Number of RCU reader threads"); 79torture_param(int, object_debug, 0, 80 "Enable debug-object double call_rcu() testing"); 81torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)"); 82torture_param(int, onoff_interval, 0, 83 "Time between CPU hotplugs (s), 0=disable"); 84torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles"); 85torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable."); 86torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable."); 87torture_param(int, stall_cpu_holdoff, 10, 88 "Time to wait before starting stall (s)."); 89torture_param(int, stat_interval, 60, 90 "Number of seconds between stats printk()s"); 91torture_param(int, stutter, 5, "Number of seconds to run/halt test"); 92torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes."); 93torture_param(int, test_boost_duration, 4, 94 "Duration of each boost test, seconds."); 95torture_param(int, test_boost_interval, 7, 96 "Interval between boost tests, seconds."); 97torture_param(bool, test_no_idle_hz, true, 98 "Test support for tickless idle CPUs"); 99torture_param(bool, verbose, true, 100 "Enable verbose debugging printk()s"); 101 102static char *torture_type = "rcu"; 103module_param(torture_type, charp, 0444); 104MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, ...)"); 105 106static int nrealreaders; 107static int ncbflooders; 108static struct task_struct *writer_task; 109static struct task_struct **fakewriter_tasks; 110static struct task_struct **reader_tasks; 111static struct task_struct *stats_task; 112static struct task_struct **cbflood_task; 113static struct task_struct *fqs_task; 114static struct task_struct *boost_tasks[NR_CPUS]; 115static struct task_struct *stall_task; 116static struct task_struct **barrier_cbs_tasks; 117static struct task_struct *barrier_task; 118 119#define RCU_TORTURE_PIPE_LEN 10 120 121struct rcu_torture { 122 struct rcu_head rtort_rcu; 123 int rtort_pipe_count; 124 struct list_head rtort_free; 125 int rtort_mbtest; 126}; 127 128static LIST_HEAD(rcu_torture_freelist); 129static struct rcu_torture __rcu *rcu_torture_current; 130static unsigned long rcu_torture_current_version; 131static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN]; 132static DEFINE_SPINLOCK(rcu_torture_lock); 133static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], 134 rcu_torture_count) = { 0 }; 135static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], 136 rcu_torture_batch) = { 0 }; 137static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1]; 138static atomic_t n_rcu_torture_alloc; 139static atomic_t n_rcu_torture_alloc_fail; 140static atomic_t n_rcu_torture_free; 141static atomic_t n_rcu_torture_mberror; 142static atomic_t n_rcu_torture_error; 143static long n_rcu_torture_barrier_error; 144static long n_rcu_torture_boost_ktrerror; 145static long n_rcu_torture_boost_rterror; 146static long n_rcu_torture_boost_failure; 147static long n_rcu_torture_boosts; 148static long n_rcu_torture_timers; 149static long n_barrier_attempts; 150static long n_barrier_successes; 151static atomic_long_t n_cbfloods; 152static struct list_head rcu_torture_removed; 153 154static int rcu_torture_writer_state; 155#define RTWS_FIXED_DELAY 0 156#define RTWS_DELAY 1 157#define RTWS_REPLACE 2 158#define RTWS_DEF_FREE 3 159#define RTWS_EXP_SYNC 4 160#define RTWS_COND_GET 5 161#define RTWS_COND_SYNC 6 162#define RTWS_SYNC 7 163#define RTWS_STUTTER 8 164#define RTWS_STOPPING 9 165 166#if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE) 167#define RCUTORTURE_RUNNABLE_INIT 1 168#else 169#define RCUTORTURE_RUNNABLE_INIT 0 170#endif 171static int torture_runnable = RCUTORTURE_RUNNABLE_INIT; 172module_param(torture_runnable, int, 0444); 173MODULE_PARM_DESC(torture_runnable, "Start rcutorture at boot"); 174 175#if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) 176#define rcu_can_boost() 1 177#else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */ 178#define rcu_can_boost() 0 179#endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */ 180 181#ifdef CONFIG_RCU_TRACE 182static u64 notrace rcu_trace_clock_local(void) 183{ 184 u64 ts = trace_clock_local(); 185 unsigned long __maybe_unused ts_rem = do_div(ts, NSEC_PER_USEC); 186 return ts; 187} 188#else /* #ifdef CONFIG_RCU_TRACE */ 189static u64 notrace rcu_trace_clock_local(void) 190{ 191 return 0ULL; 192} 193#endif /* #else #ifdef CONFIG_RCU_TRACE */ 194 195static unsigned long boost_starttime; /* jiffies of next boost test start. */ 196static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */ 197 /* and boost task create/destroy. */ 198static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */ 199static bool barrier_phase; /* Test phase. */ 200static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */ 201static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */ 202static DECLARE_WAIT_QUEUE_HEAD(barrier_wq); 203 204/* 205 * Allocate an element from the rcu_tortures pool. 206 */ 207static struct rcu_torture * 208rcu_torture_alloc(void) 209{ 210 struct list_head *p; 211 212 spin_lock_bh(&rcu_torture_lock); 213 if (list_empty(&rcu_torture_freelist)) { 214 atomic_inc(&n_rcu_torture_alloc_fail); 215 spin_unlock_bh(&rcu_torture_lock); 216 return NULL; 217 } 218 atomic_inc(&n_rcu_torture_alloc); 219 p = rcu_torture_freelist.next; 220 list_del_init(p); 221 spin_unlock_bh(&rcu_torture_lock); 222 return container_of(p, struct rcu_torture, rtort_free); 223} 224 225/* 226 * Free an element to the rcu_tortures pool. 227 */ 228static void 229rcu_torture_free(struct rcu_torture *p) 230{ 231 atomic_inc(&n_rcu_torture_free); 232 spin_lock_bh(&rcu_torture_lock); 233 list_add_tail(&p->rtort_free, &rcu_torture_freelist); 234 spin_unlock_bh(&rcu_torture_lock); 235} 236 237/* 238 * Operations vector for selecting different types of tests. 239 */ 240 241struct rcu_torture_ops { 242 int ttype; 243 void (*init)(void); 244 int (*readlock)(void); 245 void (*read_delay)(struct torture_random_state *rrsp); 246 void (*readunlock)(int idx); 247 unsigned long (*started)(void); 248 unsigned long (*completed)(void); 249 void (*deferred_free)(struct rcu_torture *p); 250 void (*sync)(void); 251 void (*exp_sync)(void); 252 unsigned long (*get_state)(void); 253 void (*cond_sync)(unsigned long oldstate); 254 void (*call)(struct rcu_head *head, void (*func)(struct rcu_head *rcu)); 255 void (*cb_barrier)(void); 256 void (*fqs)(void); 257 void (*stats)(void); 258 int irq_capable; 259 int can_boost; 260 const char *name; 261}; 262 263static struct rcu_torture_ops *cur_ops; 264 265/* 266 * Definitions for rcu torture testing. 267 */ 268 269static int rcu_torture_read_lock(void) __acquires(RCU) 270{ 271 rcu_read_lock(); 272 return 0; 273} 274 275static void rcu_read_delay(struct torture_random_state *rrsp) 276{ 277 const unsigned long shortdelay_us = 200; 278 const unsigned long longdelay_ms = 50; 279 280 /* We want a short delay sometimes to make a reader delay the grace 281 * period, and we want a long delay occasionally to trigger 282 * force_quiescent_state. */ 283 284 if (!(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) 285 mdelay(longdelay_ms); 286 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) 287 udelay(shortdelay_us); 288#ifdef CONFIG_PREEMPT 289 if (!preempt_count() && 290 !(torture_random(rrsp) % (nrealreaders * 20000))) 291 preempt_schedule(); /* No QS if preempt_disable() in effect */ 292#endif 293} 294 295static void rcu_torture_read_unlock(int idx) __releases(RCU) 296{ 297 rcu_read_unlock(); 298} 299 300/* 301 * Update callback in the pipe. This should be invoked after a grace period. 302 */ 303static bool 304rcu_torture_pipe_update_one(struct rcu_torture *rp) 305{ 306 int i; 307 308 i = rp->rtort_pipe_count; 309 if (i > RCU_TORTURE_PIPE_LEN) 310 i = RCU_TORTURE_PIPE_LEN; 311 atomic_inc(&rcu_torture_wcount[i]); 312 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) { 313 rp->rtort_mbtest = 0; 314 return true; 315 } 316 return false; 317} 318 319/* 320 * Update all callbacks in the pipe. Suitable for synchronous grace-period 321 * primitives. 322 */ 323static void 324rcu_torture_pipe_update(struct rcu_torture *old_rp) 325{ 326 struct rcu_torture *rp; 327 struct rcu_torture *rp1; 328 329 if (old_rp) 330 list_add(&old_rp->rtort_free, &rcu_torture_removed); 331 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) { 332 if (rcu_torture_pipe_update_one(rp)) { 333 list_del(&rp->rtort_free); 334 rcu_torture_free(rp); 335 } 336 } 337} 338 339static void 340rcu_torture_cb(struct rcu_head *p) 341{ 342 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu); 343 344 if (torture_must_stop_irq()) { 345 /* Test is ending, just drop callbacks on the floor. */ 346 /* The next initialization will pick up the pieces. */ 347 return; 348 } 349 if (rcu_torture_pipe_update_one(rp)) 350 rcu_torture_free(rp); 351 else 352 cur_ops->deferred_free(rp); 353} 354 355static unsigned long rcu_no_completed(void) 356{ 357 return 0; 358} 359 360static void rcu_torture_deferred_free(struct rcu_torture *p) 361{ 362 call_rcu(&p->rtort_rcu, rcu_torture_cb); 363} 364 365static void rcu_sync_torture_init(void) 366{ 367 INIT_LIST_HEAD(&rcu_torture_removed); 368} 369 370static struct rcu_torture_ops rcu_ops = { 371 .ttype = RCU_FLAVOR, 372 .init = rcu_sync_torture_init, 373 .readlock = rcu_torture_read_lock, 374 .read_delay = rcu_read_delay, 375 .readunlock = rcu_torture_read_unlock, 376 .started = rcu_batches_started, 377 .completed = rcu_batches_completed, 378 .deferred_free = rcu_torture_deferred_free, 379 .sync = synchronize_rcu, 380 .exp_sync = synchronize_rcu_expedited, 381 .get_state = get_state_synchronize_rcu, 382 .cond_sync = cond_synchronize_rcu, 383 .call = call_rcu, 384 .cb_barrier = rcu_barrier, 385 .fqs = rcu_force_quiescent_state, 386 .stats = NULL, 387 .irq_capable = 1, 388 .can_boost = rcu_can_boost(), 389 .name = "rcu" 390}; 391 392/* 393 * Definitions for rcu_bh torture testing. 394 */ 395 396static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH) 397{ 398 rcu_read_lock_bh(); 399 return 0; 400} 401 402static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH) 403{ 404 rcu_read_unlock_bh(); 405} 406 407static void rcu_bh_torture_deferred_free(struct rcu_torture *p) 408{ 409 call_rcu_bh(&p->rtort_rcu, rcu_torture_cb); 410} 411 412static struct rcu_torture_ops rcu_bh_ops = { 413 .ttype = RCU_BH_FLAVOR, 414 .init = rcu_sync_torture_init, 415 .readlock = rcu_bh_torture_read_lock, 416 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 417 .readunlock = rcu_bh_torture_read_unlock, 418 .started = rcu_batches_started_bh, 419 .completed = rcu_batches_completed_bh, 420 .deferred_free = rcu_bh_torture_deferred_free, 421 .sync = synchronize_rcu_bh, 422 .exp_sync = synchronize_rcu_bh_expedited, 423 .call = call_rcu_bh, 424 .cb_barrier = rcu_barrier_bh, 425 .fqs = rcu_bh_force_quiescent_state, 426 .stats = NULL, 427 .irq_capable = 1, 428 .name = "rcu_bh" 429}; 430 431/* 432 * Don't even think about trying any of these in real life!!! 433 * The names includes "busted", and they really means it! 434 * The only purpose of these functions is to provide a buggy RCU 435 * implementation to make sure that rcutorture correctly emits 436 * buggy-RCU error messages. 437 */ 438static void rcu_busted_torture_deferred_free(struct rcu_torture *p) 439{ 440 /* This is a deliberate bug for testing purposes only! */ 441 rcu_torture_cb(&p->rtort_rcu); 442} 443 444static void synchronize_rcu_busted(void) 445{ 446 /* This is a deliberate bug for testing purposes only! */ 447} 448 449static void 450call_rcu_busted(struct rcu_head *head, void (*func)(struct rcu_head *rcu)) 451{ 452 /* This is a deliberate bug for testing purposes only! */ 453 func(head); 454} 455 456static struct rcu_torture_ops rcu_busted_ops = { 457 .ttype = INVALID_RCU_FLAVOR, 458 .init = rcu_sync_torture_init, 459 .readlock = rcu_torture_read_lock, 460 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 461 .readunlock = rcu_torture_read_unlock, 462 .started = rcu_no_completed, 463 .completed = rcu_no_completed, 464 .deferred_free = rcu_busted_torture_deferred_free, 465 .sync = synchronize_rcu_busted, 466 .exp_sync = synchronize_rcu_busted, 467 .call = call_rcu_busted, 468 .cb_barrier = NULL, 469 .fqs = NULL, 470 .stats = NULL, 471 .irq_capable = 1, 472 .name = "rcu_busted" 473}; 474 475/* 476 * Definitions for srcu torture testing. 477 */ 478 479DEFINE_STATIC_SRCU(srcu_ctl); 480 481static int srcu_torture_read_lock(void) __acquires(&srcu_ctl) 482{ 483 return srcu_read_lock(&srcu_ctl); 484} 485 486static void srcu_read_delay(struct torture_random_state *rrsp) 487{ 488 long delay; 489 const long uspertick = 1000000 / HZ; 490 const long longdelay = 10; 491 492 /* We want there to be long-running readers, but not all the time. */ 493 494 delay = torture_random(rrsp) % 495 (nrealreaders * 2 * longdelay * uspertick); 496 if (!delay) 497 schedule_timeout_interruptible(longdelay); 498 else 499 rcu_read_delay(rrsp); 500} 501 502static void srcu_torture_read_unlock(int idx) __releases(&srcu_ctl) 503{ 504 srcu_read_unlock(&srcu_ctl, idx); 505} 506 507static unsigned long srcu_torture_completed(void) 508{ 509 return srcu_batches_completed(&srcu_ctl); 510} 511 512static void srcu_torture_deferred_free(struct rcu_torture *rp) 513{ 514 call_srcu(&srcu_ctl, &rp->rtort_rcu, rcu_torture_cb); 515} 516 517static void srcu_torture_synchronize(void) 518{ 519 synchronize_srcu(&srcu_ctl); 520} 521 522static void srcu_torture_call(struct rcu_head *head, 523 void (*func)(struct rcu_head *head)) 524{ 525 call_srcu(&srcu_ctl, head, func); 526} 527 528static void srcu_torture_barrier(void) 529{ 530 srcu_barrier(&srcu_ctl); 531} 532 533static void srcu_torture_stats(void) 534{ 535 int cpu; 536 int idx = srcu_ctl.completed & 0x1; 537 538 pr_alert("%s%s per-CPU(idx=%d):", 539 torture_type, TORTURE_FLAG, idx); 540 for_each_possible_cpu(cpu) { 541 long c0, c1; 542 543 c0 = (long)per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx]; 544 c1 = (long)per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx]; 545 pr_cont(" %d(%ld,%ld)", cpu, c0, c1); 546 } 547 pr_cont("\n"); 548} 549 550static void srcu_torture_synchronize_expedited(void) 551{ 552 synchronize_srcu_expedited(&srcu_ctl); 553} 554 555static struct rcu_torture_ops srcu_ops = { 556 .ttype = SRCU_FLAVOR, 557 .init = rcu_sync_torture_init, 558 .readlock = srcu_torture_read_lock, 559 .read_delay = srcu_read_delay, 560 .readunlock = srcu_torture_read_unlock, 561 .started = NULL, 562 .completed = srcu_torture_completed, 563 .deferred_free = srcu_torture_deferred_free, 564 .sync = srcu_torture_synchronize, 565 .exp_sync = srcu_torture_synchronize_expedited, 566 .call = srcu_torture_call, 567 .cb_barrier = srcu_torture_barrier, 568 .stats = srcu_torture_stats, 569 .name = "srcu" 570}; 571 572/* 573 * Definitions for sched torture testing. 574 */ 575 576static int sched_torture_read_lock(void) 577{ 578 preempt_disable(); 579 return 0; 580} 581 582static void sched_torture_read_unlock(int idx) 583{ 584 preempt_enable(); 585} 586 587static void rcu_sched_torture_deferred_free(struct rcu_torture *p) 588{ 589 call_rcu_sched(&p->rtort_rcu, rcu_torture_cb); 590} 591 592static struct rcu_torture_ops sched_ops = { 593 .ttype = RCU_SCHED_FLAVOR, 594 .init = rcu_sync_torture_init, 595 .readlock = sched_torture_read_lock, 596 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 597 .readunlock = sched_torture_read_unlock, 598 .started = rcu_batches_started_sched, 599 .completed = rcu_batches_completed_sched, 600 .deferred_free = rcu_sched_torture_deferred_free, 601 .sync = synchronize_sched, 602 .exp_sync = synchronize_sched_expedited, 603 .call = call_rcu_sched, 604 .cb_barrier = rcu_barrier_sched, 605 .fqs = rcu_sched_force_quiescent_state, 606 .stats = NULL, 607 .irq_capable = 1, 608 .name = "sched" 609}; 610 611#ifdef CONFIG_TASKS_RCU 612 613/* 614 * Definitions for RCU-tasks torture testing. 615 */ 616 617static int tasks_torture_read_lock(void) 618{ 619 return 0; 620} 621 622static void tasks_torture_read_unlock(int idx) 623{ 624} 625 626static void rcu_tasks_torture_deferred_free(struct rcu_torture *p) 627{ 628 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb); 629} 630 631static struct rcu_torture_ops tasks_ops = { 632 .ttype = RCU_TASKS_FLAVOR, 633 .init = rcu_sync_torture_init, 634 .readlock = tasks_torture_read_lock, 635 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 636 .readunlock = tasks_torture_read_unlock, 637 .started = rcu_no_completed, 638 .completed = rcu_no_completed, 639 .deferred_free = rcu_tasks_torture_deferred_free, 640 .sync = synchronize_rcu_tasks, 641 .exp_sync = synchronize_rcu_tasks, 642 .call = call_rcu_tasks, 643 .cb_barrier = rcu_barrier_tasks, 644 .fqs = NULL, 645 .stats = NULL, 646 .irq_capable = 1, 647 .name = "tasks" 648}; 649 650#define RCUTORTURE_TASKS_OPS &tasks_ops, 651 652#else /* #ifdef CONFIG_TASKS_RCU */ 653 654#define RCUTORTURE_TASKS_OPS 655 656#endif /* #else #ifdef CONFIG_TASKS_RCU */ 657 658/* 659 * RCU torture priority-boost testing. Runs one real-time thread per 660 * CPU for moderate bursts, repeatedly registering RCU callbacks and 661 * spinning waiting for them to be invoked. If a given callback takes 662 * too long to be invoked, we assume that priority inversion has occurred. 663 */ 664 665struct rcu_boost_inflight { 666 struct rcu_head rcu; 667 int inflight; 668}; 669 670static void rcu_torture_boost_cb(struct rcu_head *head) 671{ 672 struct rcu_boost_inflight *rbip = 673 container_of(head, struct rcu_boost_inflight, rcu); 674 675 smp_mb(); /* Ensure RCU-core accesses precede clearing ->inflight */ 676 rbip->inflight = 0; 677} 678 679static int rcu_torture_boost(void *arg) 680{ 681 unsigned long call_rcu_time; 682 unsigned long endtime; 683 unsigned long oldstarttime; 684 struct rcu_boost_inflight rbi = { .inflight = 0 }; 685 struct sched_param sp; 686 687 VERBOSE_TOROUT_STRING("rcu_torture_boost started"); 688 689 /* Set real-time priority. */ 690 sp.sched_priority = 1; 691 if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) { 692 VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!"); 693 n_rcu_torture_boost_rterror++; 694 } 695 696 init_rcu_head_on_stack(&rbi.rcu); 697 /* Each pass through the following loop does one boost-test cycle. */ 698 do { 699 /* Wait for the next test interval. */ 700 oldstarttime = boost_starttime; 701 while (ULONG_CMP_LT(jiffies, oldstarttime)) { 702 schedule_timeout_interruptible(oldstarttime - jiffies); 703 stutter_wait("rcu_torture_boost"); 704 if (torture_must_stop()) 705 goto checkwait; 706 } 707 708 /* Do one boost-test interval. */ 709 endtime = oldstarttime + test_boost_duration * HZ; 710 call_rcu_time = jiffies; 711 while (ULONG_CMP_LT(jiffies, endtime)) { 712 /* If we don't have a callback in flight, post one. */ 713 if (!rbi.inflight) { 714 smp_mb(); /* RCU core before ->inflight = 1. */ 715 rbi.inflight = 1; 716 call_rcu(&rbi.rcu, rcu_torture_boost_cb); 717 if (jiffies - call_rcu_time > 718 test_boost_duration * HZ - HZ / 2) { 719 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed"); 720 n_rcu_torture_boost_failure++; 721 } 722 call_rcu_time = jiffies; 723 } 724 cond_resched_rcu_qs(); 725 stutter_wait("rcu_torture_boost"); 726 if (torture_must_stop()) 727 goto checkwait; 728 } 729 730 /* 731 * Set the start time of the next test interval. 732 * Yes, this is vulnerable to long delays, but such 733 * delays simply cause a false negative for the next 734 * interval. Besides, we are running at RT priority, 735 * so delays should be relatively rare. 736 */ 737 while (oldstarttime == boost_starttime && 738 !kthread_should_stop()) { 739 if (mutex_trylock(&boost_mutex)) { 740 boost_starttime = jiffies + 741 test_boost_interval * HZ; 742 n_rcu_torture_boosts++; 743 mutex_unlock(&boost_mutex); 744 break; 745 } 746 schedule_timeout_uninterruptible(1); 747 } 748 749 /* Go do the stutter. */ 750checkwait: stutter_wait("rcu_torture_boost"); 751 } while (!torture_must_stop()); 752 753 /* Clean up and exit. */ 754 while (!kthread_should_stop() || rbi.inflight) { 755 torture_shutdown_absorb("rcu_torture_boost"); 756 schedule_timeout_uninterruptible(1); 757 } 758 smp_mb(); /* order accesses to ->inflight before stack-frame death. */ 759 destroy_rcu_head_on_stack(&rbi.rcu); 760 torture_kthread_stopping("rcu_torture_boost"); 761 return 0; 762} 763 764static void rcu_torture_cbflood_cb(struct rcu_head *rhp) 765{ 766} 767 768/* 769 * RCU torture callback-flood kthread. Repeatedly induces bursts of calls 770 * to call_rcu() or analogous, increasing the probability of occurrence 771 * of callback-overflow corner cases. 772 */ 773static int 774rcu_torture_cbflood(void *arg) 775{ 776 int err = 1; 777 int i; 778 int j; 779 struct rcu_head *rhp; 780 781 if (cbflood_n_per_burst > 0 && 782 cbflood_inter_holdoff > 0 && 783 cbflood_intra_holdoff > 0 && 784 cur_ops->call && 785 cur_ops->cb_barrier) { 786 rhp = vmalloc(sizeof(*rhp) * 787 cbflood_n_burst * cbflood_n_per_burst); 788 err = !rhp; 789 } 790 if (err) { 791 VERBOSE_TOROUT_STRING("rcu_torture_cbflood disabled: Bad args or OOM"); 792 while (!torture_must_stop()) 793 schedule_timeout_interruptible(HZ); 794 return 0; 795 } 796 VERBOSE_TOROUT_STRING("rcu_torture_cbflood task started"); 797 do { 798 schedule_timeout_interruptible(cbflood_inter_holdoff); 799 atomic_long_inc(&n_cbfloods); 800 WARN_ON(signal_pending(current)); 801 for (i = 0; i < cbflood_n_burst; i++) { 802 for (j = 0; j < cbflood_n_per_burst; j++) { 803 cur_ops->call(&rhp[i * cbflood_n_per_burst + j], 804 rcu_torture_cbflood_cb); 805 } 806 schedule_timeout_interruptible(cbflood_intra_holdoff); 807 WARN_ON(signal_pending(current)); 808 } 809 cur_ops->cb_barrier(); 810 stutter_wait("rcu_torture_cbflood"); 811 } while (!torture_must_stop()); 812 vfree(rhp); 813 torture_kthread_stopping("rcu_torture_cbflood"); 814 return 0; 815} 816 817/* 818 * RCU torture force-quiescent-state kthread. Repeatedly induces 819 * bursts of calls to force_quiescent_state(), increasing the probability 820 * of occurrence of some important types of race conditions. 821 */ 822static int 823rcu_torture_fqs(void *arg) 824{ 825 unsigned long fqs_resume_time; 826 int fqs_burst_remaining; 827 828 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started"); 829 do { 830 fqs_resume_time = jiffies + fqs_stutter * HZ; 831 while (ULONG_CMP_LT(jiffies, fqs_resume_time) && 832 !kthread_should_stop()) { 833 schedule_timeout_interruptible(1); 834 } 835 fqs_burst_remaining = fqs_duration; 836 while (fqs_burst_remaining > 0 && 837 !kthread_should_stop()) { 838 cur_ops->fqs(); 839 udelay(fqs_holdoff); 840 fqs_burst_remaining -= fqs_holdoff; 841 } 842 stutter_wait("rcu_torture_fqs"); 843 } while (!torture_must_stop()); 844 torture_kthread_stopping("rcu_torture_fqs"); 845 return 0; 846} 847 848/* 849 * RCU torture writer kthread. Repeatedly substitutes a new structure 850 * for that pointed to by rcu_torture_current, freeing the old structure 851 * after a series of grace periods (the "pipeline"). 852 */ 853static int 854rcu_torture_writer(void *arg) 855{ 856 bool can_expedite = !rcu_gp_is_expedited(); 857 int expediting = 0; 858 unsigned long gp_snap; 859 bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal; 860 bool gp_sync1 = gp_sync; 861 int i; 862 struct rcu_torture *rp; 863 struct rcu_torture *old_rp; 864 static DEFINE_TORTURE_RANDOM(rand); 865 int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC, 866 RTWS_COND_GET, RTWS_SYNC }; 867 int nsynctypes = 0; 868 869 VERBOSE_TOROUT_STRING("rcu_torture_writer task started"); 870 pr_alert("%s" TORTURE_FLAG 871 " Grace periods expedited from boot/sysfs for %s,\n", 872 torture_type, cur_ops->name); 873 pr_alert("%s" TORTURE_FLAG 874 " Testing of dynamic grace-period expediting diabled.\n", 875 torture_type); 876 877 /* Initialize synctype[] array. If none set, take default. */ 878 if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync1) 879 gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true; 880 if (gp_cond1 && cur_ops->get_state && cur_ops->cond_sync) 881 synctype[nsynctypes++] = RTWS_COND_GET; 882 else if (gp_cond && (!cur_ops->get_state || !cur_ops->cond_sync)) 883 pr_alert("rcu_torture_writer: gp_cond without primitives.\n"); 884 if (gp_exp1 && cur_ops->exp_sync) 885 synctype[nsynctypes++] = RTWS_EXP_SYNC; 886 else if (gp_exp && !cur_ops->exp_sync) 887 pr_alert("rcu_torture_writer: gp_exp without primitives.\n"); 888 if (gp_normal1 && cur_ops->deferred_free) 889 synctype[nsynctypes++] = RTWS_DEF_FREE; 890 else if (gp_normal && !cur_ops->deferred_free) 891 pr_alert("rcu_torture_writer: gp_normal without primitives.\n"); 892 if (gp_sync1 && cur_ops->sync) 893 synctype[nsynctypes++] = RTWS_SYNC; 894 else if (gp_sync && !cur_ops->sync) 895 pr_alert("rcu_torture_writer: gp_sync without primitives.\n"); 896 if (WARN_ONCE(nsynctypes == 0, 897 "rcu_torture_writer: No update-side primitives.\n")) { 898 /* 899 * No updates primitives, so don't try updating. 900 * The resulting test won't be testing much, hence the 901 * above WARN_ONCE(). 902 */ 903 rcu_torture_writer_state = RTWS_STOPPING; 904 torture_kthread_stopping("rcu_torture_writer"); 905 } 906 907 do { 908 rcu_torture_writer_state = RTWS_FIXED_DELAY; 909 schedule_timeout_uninterruptible(1); 910 rp = rcu_torture_alloc(); 911 if (rp == NULL) 912 continue; 913 rp->rtort_pipe_count = 0; 914 rcu_torture_writer_state = RTWS_DELAY; 915 udelay(torture_random(&rand) & 0x3ff); 916 rcu_torture_writer_state = RTWS_REPLACE; 917 old_rp = rcu_dereference_check(rcu_torture_current, 918 current == writer_task); 919 rp->rtort_mbtest = 1; 920 rcu_assign_pointer(rcu_torture_current, rp); 921 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */ 922 if (old_rp) { 923 i = old_rp->rtort_pipe_count; 924 if (i > RCU_TORTURE_PIPE_LEN) 925 i = RCU_TORTURE_PIPE_LEN; 926 atomic_inc(&rcu_torture_wcount[i]); 927 old_rp->rtort_pipe_count++; 928 switch (synctype[torture_random(&rand) % nsynctypes]) { 929 case RTWS_DEF_FREE: 930 rcu_torture_writer_state = RTWS_DEF_FREE; 931 cur_ops->deferred_free(old_rp); 932 break; 933 case RTWS_EXP_SYNC: 934 rcu_torture_writer_state = RTWS_EXP_SYNC; 935 cur_ops->exp_sync(); 936 rcu_torture_pipe_update(old_rp); 937 break; 938 case RTWS_COND_GET: 939 rcu_torture_writer_state = RTWS_COND_GET; 940 gp_snap = cur_ops->get_state(); 941 i = torture_random(&rand) % 16; 942 if (i != 0) 943 schedule_timeout_interruptible(i); 944 udelay(torture_random(&rand) % 1000); 945 rcu_torture_writer_state = RTWS_COND_SYNC; 946 cur_ops->cond_sync(gp_snap); 947 rcu_torture_pipe_update(old_rp); 948 break; 949 case RTWS_SYNC: 950 rcu_torture_writer_state = RTWS_SYNC; 951 cur_ops->sync(); 952 rcu_torture_pipe_update(old_rp); 953 break; 954 default: 955 WARN_ON_ONCE(1); 956 break; 957 } 958 } 959 rcutorture_record_progress(++rcu_torture_current_version); 960 /* Cycle through nesting levels of rcu_expedite_gp() calls. */ 961 if (can_expedite && 962 !(torture_random(&rand) & 0xff & (!!expediting - 1))) { 963 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited()); 964 if (expediting >= 0) 965 rcu_expedite_gp(); 966 else 967 rcu_unexpedite_gp(); 968 if (++expediting > 3) 969 expediting = -expediting; 970 } 971 rcu_torture_writer_state = RTWS_STUTTER; 972 stutter_wait("rcu_torture_writer"); 973 } while (!torture_must_stop()); 974 /* Reset expediting back to unexpedited. */ 975 if (expediting > 0) 976 expediting = -expediting; 977 while (can_expedite && expediting++ < 0) 978 rcu_unexpedite_gp(); 979 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited()); 980 rcu_torture_writer_state = RTWS_STOPPING; 981 torture_kthread_stopping("rcu_torture_writer"); 982 return 0; 983} 984 985/* 986 * RCU torture fake writer kthread. Repeatedly calls sync, with a random 987 * delay between calls. 988 */ 989static int 990rcu_torture_fakewriter(void *arg) 991{ 992 DEFINE_TORTURE_RANDOM(rand); 993 994 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started"); 995 set_user_nice(current, MAX_NICE); 996 997 do { 998 schedule_timeout_uninterruptible(1 + torture_random(&rand)%10); 999 udelay(torture_random(&rand) & 0x3ff); 1000 if (cur_ops->cb_barrier != NULL && 1001 torture_random(&rand) % (nfakewriters * 8) == 0) { 1002 cur_ops->cb_barrier(); 1003 } else if (gp_normal == gp_exp) { 1004 if (torture_random(&rand) & 0x80) 1005 cur_ops->sync(); 1006 else 1007 cur_ops->exp_sync(); 1008 } else if (gp_normal) { 1009 cur_ops->sync(); 1010 } else { 1011 cur_ops->exp_sync(); 1012 } 1013 stutter_wait("rcu_torture_fakewriter"); 1014 } while (!torture_must_stop()); 1015 1016 torture_kthread_stopping("rcu_torture_fakewriter"); 1017 return 0; 1018} 1019 1020static void rcutorture_trace_dump(void) 1021{ 1022 static atomic_t beenhere = ATOMIC_INIT(0); 1023 1024 if (atomic_read(&beenhere)) 1025 return; 1026 if (atomic_xchg(&beenhere, 1) != 0) 1027 return; 1028 ftrace_dump(DUMP_ALL); 1029} 1030 1031/* 1032 * RCU torture reader from timer handler. Dereferences rcu_torture_current, 1033 * incrementing the corresponding element of the pipeline array. The 1034 * counter in the element should never be greater than 1, otherwise, the 1035 * RCU implementation is broken. 1036 */ 1037static void rcu_torture_timer(unsigned long unused) 1038{ 1039 int idx; 1040 unsigned long started; 1041 unsigned long completed; 1042 static DEFINE_TORTURE_RANDOM(rand); 1043 static DEFINE_SPINLOCK(rand_lock); 1044 struct rcu_torture *p; 1045 int pipe_count; 1046 unsigned long long ts; 1047 1048 idx = cur_ops->readlock(); 1049 if (cur_ops->started) 1050 started = cur_ops->started(); 1051 else 1052 started = cur_ops->completed(); 1053 ts = rcu_trace_clock_local(); 1054 p = rcu_dereference_check(rcu_torture_current, 1055 rcu_read_lock_bh_held() || 1056 rcu_read_lock_sched_held() || 1057 srcu_read_lock_held(&srcu_ctl)); 1058 if (p == NULL) { 1059 /* Leave because rcu_torture_writer is not yet underway */ 1060 cur_ops->readunlock(idx); 1061 return; 1062 } 1063 if (p->rtort_mbtest == 0) 1064 atomic_inc(&n_rcu_torture_mberror); 1065 spin_lock(&rand_lock); 1066 cur_ops->read_delay(&rand); 1067 n_rcu_torture_timers++; 1068 spin_unlock(&rand_lock); 1069 preempt_disable(); 1070 pipe_count = p->rtort_pipe_count; 1071 if (pipe_count > RCU_TORTURE_PIPE_LEN) { 1072 /* Should not happen, but... */ 1073 pipe_count = RCU_TORTURE_PIPE_LEN; 1074 } 1075 completed = cur_ops->completed(); 1076 if (pipe_count > 1) { 1077 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, ts, 1078 started, completed); 1079 rcutorture_trace_dump(); 1080 } 1081 __this_cpu_inc(rcu_torture_count[pipe_count]); 1082 completed = completed - started; 1083 if (cur_ops->started) 1084 completed++; 1085 if (completed > RCU_TORTURE_PIPE_LEN) { 1086 /* Should not happen, but... */ 1087 completed = RCU_TORTURE_PIPE_LEN; 1088 } 1089 __this_cpu_inc(rcu_torture_batch[completed]); 1090 preempt_enable(); 1091 cur_ops->readunlock(idx); 1092} 1093 1094/* 1095 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current, 1096 * incrementing the corresponding element of the pipeline array. The 1097 * counter in the element should never be greater than 1, otherwise, the 1098 * RCU implementation is broken. 1099 */ 1100static int 1101rcu_torture_reader(void *arg) 1102{ 1103 unsigned long started; 1104 unsigned long completed; 1105 int idx; 1106 DEFINE_TORTURE_RANDOM(rand); 1107 struct rcu_torture *p; 1108 int pipe_count; 1109 struct timer_list t; 1110 unsigned long long ts; 1111 1112 VERBOSE_TOROUT_STRING("rcu_torture_reader task started"); 1113 set_user_nice(current, MAX_NICE); 1114 if (irqreader && cur_ops->irq_capable) 1115 setup_timer_on_stack(&t, rcu_torture_timer, 0); 1116 1117 do { 1118 if (irqreader && cur_ops->irq_capable) { 1119 if (!timer_pending(&t)) 1120 mod_timer(&t, jiffies + 1); 1121 } 1122 idx = cur_ops->readlock(); 1123 if (cur_ops->started) 1124 started = cur_ops->started(); 1125 else 1126 started = cur_ops->completed(); 1127 ts = rcu_trace_clock_local(); 1128 p = rcu_dereference_check(rcu_torture_current, 1129 rcu_read_lock_bh_held() || 1130 rcu_read_lock_sched_held() || 1131 srcu_read_lock_held(&srcu_ctl)); 1132 if (p == NULL) { 1133 /* Wait for rcu_torture_writer to get underway */ 1134 cur_ops->readunlock(idx); 1135 schedule_timeout_interruptible(HZ); 1136 continue; 1137 } 1138 if (p->rtort_mbtest == 0) 1139 atomic_inc(&n_rcu_torture_mberror); 1140 cur_ops->read_delay(&rand); 1141 preempt_disable(); 1142 pipe_count = p->rtort_pipe_count; 1143 if (pipe_count > RCU_TORTURE_PIPE_LEN) { 1144 /* Should not happen, but... */ 1145 pipe_count = RCU_TORTURE_PIPE_LEN; 1146 } 1147 completed = cur_ops->completed(); 1148 if (pipe_count > 1) { 1149 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, 1150 ts, started, completed); 1151 rcutorture_trace_dump(); 1152 } 1153 __this_cpu_inc(rcu_torture_count[pipe_count]); 1154 completed = completed - started; 1155 if (cur_ops->started) 1156 completed++; 1157 if (completed > RCU_TORTURE_PIPE_LEN) { 1158 /* Should not happen, but... */ 1159 completed = RCU_TORTURE_PIPE_LEN; 1160 } 1161 __this_cpu_inc(rcu_torture_batch[completed]); 1162 preempt_enable(); 1163 cur_ops->readunlock(idx); 1164 cond_resched_rcu_qs(); 1165 stutter_wait("rcu_torture_reader"); 1166 } while (!torture_must_stop()); 1167 if (irqreader && cur_ops->irq_capable) { 1168 del_timer_sync(&t); 1169 destroy_timer_on_stack(&t); 1170 } 1171 torture_kthread_stopping("rcu_torture_reader"); 1172 return 0; 1173} 1174 1175/* 1176 * Print torture statistics. Caller must ensure that there is only 1177 * one call to this function at a given time!!! This is normally 1178 * accomplished by relying on the module system to only have one copy 1179 * of the module loaded, and then by giving the rcu_torture_stats 1180 * kthread full control (or the init/cleanup functions when rcu_torture_stats 1181 * thread is not running). 1182 */ 1183static void 1184rcu_torture_stats_print(void) 1185{ 1186 int cpu; 1187 int i; 1188 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; 1189 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; 1190 static unsigned long rtcv_snap = ULONG_MAX; 1191 1192 for_each_possible_cpu(cpu) { 1193 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 1194 pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i]; 1195 batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i]; 1196 } 1197 } 1198 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) { 1199 if (pipesummary[i] != 0) 1200 break; 1201 } 1202 1203 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1204 pr_cont("rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ", 1205 rcu_torture_current, 1206 rcu_torture_current_version, 1207 list_empty(&rcu_torture_freelist), 1208 atomic_read(&n_rcu_torture_alloc), 1209 atomic_read(&n_rcu_torture_alloc_fail), 1210 atomic_read(&n_rcu_torture_free)); 1211 pr_cont("rtmbe: %d rtbke: %ld rtbre: %ld ", 1212 atomic_read(&n_rcu_torture_mberror), 1213 n_rcu_torture_boost_ktrerror, 1214 n_rcu_torture_boost_rterror); 1215 pr_cont("rtbf: %ld rtb: %ld nt: %ld ", 1216 n_rcu_torture_boost_failure, 1217 n_rcu_torture_boosts, 1218 n_rcu_torture_timers); 1219 torture_onoff_stats(); 1220 pr_cont("barrier: %ld/%ld:%ld ", 1221 n_barrier_successes, 1222 n_barrier_attempts, 1223 n_rcu_torture_barrier_error); 1224 pr_cont("cbflood: %ld\n", atomic_long_read(&n_cbfloods)); 1225 1226 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1227 if (atomic_read(&n_rcu_torture_mberror) != 0 || 1228 n_rcu_torture_barrier_error != 0 || 1229 n_rcu_torture_boost_ktrerror != 0 || 1230 n_rcu_torture_boost_rterror != 0 || 1231 n_rcu_torture_boost_failure != 0 || 1232 i > 1) { 1233 pr_cont("%s", "!!! "); 1234 atomic_inc(&n_rcu_torture_error); 1235 WARN_ON_ONCE(1); 1236 } 1237 pr_cont("Reader Pipe: "); 1238 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 1239 pr_cont(" %ld", pipesummary[i]); 1240 pr_cont("\n"); 1241 1242 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1243 pr_cont("Reader Batch: "); 1244 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 1245 pr_cont(" %ld", batchsummary[i]); 1246 pr_cont("\n"); 1247 1248 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1249 pr_cont("Free-Block Circulation: "); 1250 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 1251 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i])); 1252 } 1253 pr_cont("\n"); 1254 1255 if (cur_ops->stats) 1256 cur_ops->stats(); 1257 if (rtcv_snap == rcu_torture_current_version && 1258 rcu_torture_current != NULL) { 1259 int __maybe_unused flags; 1260 unsigned long __maybe_unused gpnum; 1261 unsigned long __maybe_unused completed; 1262 1263 rcutorture_get_gp_data(cur_ops->ttype, 1264 &flags, &gpnum, &completed); 1265 pr_alert("??? Writer stall state %d g%lu c%lu f%#x\n", 1266 rcu_torture_writer_state, 1267 gpnum, completed, flags); 1268 show_rcu_gp_kthreads(); 1269 rcutorture_trace_dump(); 1270 } 1271 rtcv_snap = rcu_torture_current_version; 1272} 1273 1274/* 1275 * Periodically prints torture statistics, if periodic statistics printing 1276 * was specified via the stat_interval module parameter. 1277 */ 1278static int 1279rcu_torture_stats(void *arg) 1280{ 1281 VERBOSE_TOROUT_STRING("rcu_torture_stats task started"); 1282 do { 1283 schedule_timeout_interruptible(stat_interval * HZ); 1284 rcu_torture_stats_print(); 1285 torture_shutdown_absorb("rcu_torture_stats"); 1286 } while (!torture_must_stop()); 1287 torture_kthread_stopping("rcu_torture_stats"); 1288 return 0; 1289} 1290 1291static inline void 1292rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag) 1293{ 1294 pr_alert("%s" TORTURE_FLAG 1295 "--- %s: nreaders=%d nfakewriters=%d " 1296 "stat_interval=%d verbose=%d test_no_idle_hz=%d " 1297 "shuffle_interval=%d stutter=%d irqreader=%d " 1298 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d " 1299 "test_boost=%d/%d test_boost_interval=%d " 1300 "test_boost_duration=%d shutdown_secs=%d " 1301 "stall_cpu=%d stall_cpu_holdoff=%d " 1302 "n_barrier_cbs=%d " 1303 "onoff_interval=%d onoff_holdoff=%d\n", 1304 torture_type, tag, nrealreaders, nfakewriters, 1305 stat_interval, verbose, test_no_idle_hz, shuffle_interval, 1306 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter, 1307 test_boost, cur_ops->can_boost, 1308 test_boost_interval, test_boost_duration, shutdown_secs, 1309 stall_cpu, stall_cpu_holdoff, 1310 n_barrier_cbs, 1311 onoff_interval, onoff_holdoff); 1312} 1313 1314static void rcutorture_booster_cleanup(int cpu) 1315{ 1316 struct task_struct *t; 1317 1318 if (boost_tasks[cpu] == NULL) 1319 return; 1320 mutex_lock(&boost_mutex); 1321 t = boost_tasks[cpu]; 1322 boost_tasks[cpu] = NULL; 1323 mutex_unlock(&boost_mutex); 1324 1325 /* This must be outside of the mutex, otherwise deadlock! */ 1326 torture_stop_kthread(rcu_torture_boost, t); 1327} 1328 1329static int rcutorture_booster_init(int cpu) 1330{ 1331 int retval; 1332 1333 if (boost_tasks[cpu] != NULL) 1334 return 0; /* Already created, nothing more to do. */ 1335 1336 /* Don't allow time recalculation while creating a new task. */ 1337 mutex_lock(&boost_mutex); 1338 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task"); 1339 boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL, 1340 cpu_to_node(cpu), 1341 "rcu_torture_boost"); 1342 if (IS_ERR(boost_tasks[cpu])) { 1343 retval = PTR_ERR(boost_tasks[cpu]); 1344 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed"); 1345 n_rcu_torture_boost_ktrerror++; 1346 boost_tasks[cpu] = NULL; 1347 mutex_unlock(&boost_mutex); 1348 return retval; 1349 } 1350 kthread_bind(boost_tasks[cpu], cpu); 1351 wake_up_process(boost_tasks[cpu]); 1352 mutex_unlock(&boost_mutex); 1353 return 0; 1354} 1355 1356/* 1357 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then 1358 * induces a CPU stall for the time specified by stall_cpu. 1359 */ 1360static int rcu_torture_stall(void *args) 1361{ 1362 unsigned long stop_at; 1363 1364 VERBOSE_TOROUT_STRING("rcu_torture_stall task started"); 1365 if (stall_cpu_holdoff > 0) { 1366 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff"); 1367 schedule_timeout_interruptible(stall_cpu_holdoff * HZ); 1368 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff"); 1369 } 1370 if (!kthread_should_stop()) { 1371 stop_at = get_seconds() + stall_cpu; 1372 /* RCU CPU stall is expected behavior in following code. */ 1373 pr_alert("rcu_torture_stall start.\n"); 1374 rcu_read_lock(); 1375 preempt_disable(); 1376 while (ULONG_CMP_LT(get_seconds(), stop_at)) 1377 continue; /* Induce RCU CPU stall warning. */ 1378 preempt_enable(); 1379 rcu_read_unlock(); 1380 pr_alert("rcu_torture_stall end.\n"); 1381 } 1382 torture_shutdown_absorb("rcu_torture_stall"); 1383 while (!kthread_should_stop()) 1384 schedule_timeout_interruptible(10 * HZ); 1385 return 0; 1386} 1387 1388/* Spawn CPU-stall kthread, if stall_cpu specified. */ 1389static int __init rcu_torture_stall_init(void) 1390{ 1391 if (stall_cpu <= 0) 1392 return 0; 1393 return torture_create_kthread(rcu_torture_stall, NULL, stall_task); 1394} 1395 1396/* Callback function for RCU barrier testing. */ 1397static void rcu_torture_barrier_cbf(struct rcu_head *rcu) 1398{ 1399 atomic_inc(&barrier_cbs_invoked); 1400} 1401 1402/* kthread function to register callbacks used to test RCU barriers. */ 1403static int rcu_torture_barrier_cbs(void *arg) 1404{ 1405 long myid = (long)arg; 1406 bool lastphase = 0; 1407 bool newphase; 1408 struct rcu_head rcu; 1409 1410 init_rcu_head_on_stack(&rcu); 1411 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started"); 1412 set_user_nice(current, MAX_NICE); 1413 do { 1414 wait_event(barrier_cbs_wq[myid], 1415 (newphase = 1416 ACCESS_ONCE(barrier_phase)) != lastphase || 1417 torture_must_stop()); 1418 lastphase = newphase; 1419 smp_mb(); /* ensure barrier_phase load before ->call(). */ 1420 if (torture_must_stop()) 1421 break; 1422 cur_ops->call(&rcu, rcu_torture_barrier_cbf); 1423 if (atomic_dec_and_test(&barrier_cbs_count)) 1424 wake_up(&barrier_wq); 1425 } while (!torture_must_stop()); 1426 if (cur_ops->cb_barrier != NULL) 1427 cur_ops->cb_barrier(); 1428 destroy_rcu_head_on_stack(&rcu); 1429 torture_kthread_stopping("rcu_torture_barrier_cbs"); 1430 return 0; 1431} 1432 1433/* kthread function to drive and coordinate RCU barrier testing. */ 1434static int rcu_torture_barrier(void *arg) 1435{ 1436 int i; 1437 1438 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting"); 1439 do { 1440 atomic_set(&barrier_cbs_invoked, 0); 1441 atomic_set(&barrier_cbs_count, n_barrier_cbs); 1442 smp_mb(); /* Ensure barrier_phase after prior assignments. */ 1443 barrier_phase = !barrier_phase; 1444 for (i = 0; i < n_barrier_cbs; i++) 1445 wake_up(&barrier_cbs_wq[i]); 1446 wait_event(barrier_wq, 1447 atomic_read(&barrier_cbs_count) == 0 || 1448 torture_must_stop()); 1449 if (torture_must_stop()) 1450 break; 1451 n_barrier_attempts++; 1452 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */ 1453 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) { 1454 n_rcu_torture_barrier_error++; 1455 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n", 1456 atomic_read(&barrier_cbs_invoked), 1457 n_barrier_cbs); 1458 WARN_ON_ONCE(1); 1459 } 1460 n_barrier_successes++; 1461 schedule_timeout_interruptible(HZ / 10); 1462 } while (!torture_must_stop()); 1463 torture_kthread_stopping("rcu_torture_barrier"); 1464 return 0; 1465} 1466 1467/* Initialize RCU barrier testing. */ 1468static int rcu_torture_barrier_init(void) 1469{ 1470 int i; 1471 int ret; 1472 1473 if (n_barrier_cbs == 0) 1474 return 0; 1475 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) { 1476 pr_alert("%s" TORTURE_FLAG 1477 " Call or barrier ops missing for %s,\n", 1478 torture_type, cur_ops->name); 1479 pr_alert("%s" TORTURE_FLAG 1480 " RCU barrier testing omitted from run.\n", 1481 torture_type); 1482 return 0; 1483 } 1484 atomic_set(&barrier_cbs_count, 0); 1485 atomic_set(&barrier_cbs_invoked, 0); 1486 barrier_cbs_tasks = 1487 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_tasks[0]), 1488 GFP_KERNEL); 1489 barrier_cbs_wq = 1490 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_wq[0]), 1491 GFP_KERNEL); 1492 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq) 1493 return -ENOMEM; 1494 for (i = 0; i < n_barrier_cbs; i++) { 1495 init_waitqueue_head(&barrier_cbs_wq[i]); 1496 ret = torture_create_kthread(rcu_torture_barrier_cbs, 1497 (void *)(long)i, 1498 barrier_cbs_tasks[i]); 1499 if (ret) 1500 return ret; 1501 } 1502 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task); 1503} 1504 1505/* Clean up after RCU barrier testing. */ 1506static void rcu_torture_barrier_cleanup(void) 1507{ 1508 int i; 1509 1510 torture_stop_kthread(rcu_torture_barrier, barrier_task); 1511 if (barrier_cbs_tasks != NULL) { 1512 for (i = 0; i < n_barrier_cbs; i++) 1513 torture_stop_kthread(rcu_torture_barrier_cbs, 1514 barrier_cbs_tasks[i]); 1515 kfree(barrier_cbs_tasks); 1516 barrier_cbs_tasks = NULL; 1517 } 1518 if (barrier_cbs_wq != NULL) { 1519 kfree(barrier_cbs_wq); 1520 barrier_cbs_wq = NULL; 1521 } 1522} 1523 1524static int rcutorture_cpu_notify(struct notifier_block *self, 1525 unsigned long action, void *hcpu) 1526{ 1527 long cpu = (long)hcpu; 1528 1529 switch (action) { 1530 case CPU_ONLINE: 1531 case CPU_DOWN_FAILED: 1532 (void)rcutorture_booster_init(cpu); 1533 break; 1534 case CPU_DOWN_PREPARE: 1535 rcutorture_booster_cleanup(cpu); 1536 break; 1537 default: 1538 break; 1539 } 1540 return NOTIFY_OK; 1541} 1542 1543static struct notifier_block rcutorture_cpu_nb = { 1544 .notifier_call = rcutorture_cpu_notify, 1545}; 1546 1547static void 1548rcu_torture_cleanup(void) 1549{ 1550 int i; 1551 1552 rcutorture_record_test_transition(); 1553 if (torture_cleanup_begin()) { 1554 if (cur_ops->cb_barrier != NULL) 1555 cur_ops->cb_barrier(); 1556 return; 1557 } 1558 1559 rcu_torture_barrier_cleanup(); 1560 torture_stop_kthread(rcu_torture_stall, stall_task); 1561 torture_stop_kthread(rcu_torture_writer, writer_task); 1562 1563 if (reader_tasks) { 1564 for (i = 0; i < nrealreaders; i++) 1565 torture_stop_kthread(rcu_torture_reader, 1566 reader_tasks[i]); 1567 kfree(reader_tasks); 1568 } 1569 rcu_torture_current = NULL; 1570 1571 if (fakewriter_tasks) { 1572 for (i = 0; i < nfakewriters; i++) { 1573 torture_stop_kthread(rcu_torture_fakewriter, 1574 fakewriter_tasks[i]); 1575 } 1576 kfree(fakewriter_tasks); 1577 fakewriter_tasks = NULL; 1578 } 1579 1580 torture_stop_kthread(rcu_torture_stats, stats_task); 1581 torture_stop_kthread(rcu_torture_fqs, fqs_task); 1582 for (i = 0; i < ncbflooders; i++) 1583 torture_stop_kthread(rcu_torture_cbflood, cbflood_task[i]); 1584 if ((test_boost == 1 && cur_ops->can_boost) || 1585 test_boost == 2) { 1586 unregister_cpu_notifier(&rcutorture_cpu_nb); 1587 for_each_possible_cpu(i) 1588 rcutorture_booster_cleanup(i); 1589 } 1590 1591 /* Wait for all RCU callbacks to fire. */ 1592 1593 if (cur_ops->cb_barrier != NULL) 1594 cur_ops->cb_barrier(); 1595 1596 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */ 1597 1598 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error) 1599 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE"); 1600 else if (torture_onoff_failures()) 1601 rcu_torture_print_module_parms(cur_ops, 1602 "End of test: RCU_HOTPLUG"); 1603 else 1604 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS"); 1605 torture_cleanup_end(); 1606} 1607 1608#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD 1609static void rcu_torture_leak_cb(struct rcu_head *rhp) 1610{ 1611} 1612 1613static void rcu_torture_err_cb(struct rcu_head *rhp) 1614{ 1615 /* 1616 * This -might- happen due to race conditions, but is unlikely. 1617 * The scenario that leads to this happening is that the 1618 * first of the pair of duplicate callbacks is queued, 1619 * someone else starts a grace period that includes that 1620 * callback, then the second of the pair must wait for the 1621 * next grace period. Unlikely, but can happen. If it 1622 * does happen, the debug-objects subsystem won't have splatted. 1623 */ 1624 pr_alert("rcutorture: duplicated callback was invoked.\n"); 1625} 1626#endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 1627 1628/* 1629 * Verify that double-free causes debug-objects to complain, but only 1630 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test 1631 * cannot be carried out. 1632 */ 1633static void rcu_test_debug_objects(void) 1634{ 1635#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD 1636 struct rcu_head rh1; 1637 struct rcu_head rh2; 1638 1639 init_rcu_head_on_stack(&rh1); 1640 init_rcu_head_on_stack(&rh2); 1641 pr_alert("rcutorture: WARN: Duplicate call_rcu() test starting.\n"); 1642 1643 /* Try to queue the rh2 pair of callbacks for the same grace period. */ 1644 preempt_disable(); /* Prevent preemption from interrupting test. */ 1645 rcu_read_lock(); /* Make it impossible to finish a grace period. */ 1646 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */ 1647 local_irq_disable(); /* Make it harder to start a new grace period. */ 1648 call_rcu(&rh2, rcu_torture_leak_cb); 1649 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */ 1650 local_irq_enable(); 1651 rcu_read_unlock(); 1652 preempt_enable(); 1653 1654 /* Wait for them all to get done so we can safely return. */ 1655 rcu_barrier(); 1656 pr_alert("rcutorture: WARN: Duplicate call_rcu() test complete.\n"); 1657 destroy_rcu_head_on_stack(&rh1); 1658 destroy_rcu_head_on_stack(&rh2); 1659#else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 1660 pr_alert("rcutorture: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n"); 1661#endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 1662} 1663 1664static int __init 1665rcu_torture_init(void) 1666{ 1667 int i; 1668 int cpu; 1669 int firsterr = 0; 1670 static struct rcu_torture_ops *torture_ops[] = { 1671 &rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &sched_ops, 1672 RCUTORTURE_TASKS_OPS 1673 }; 1674 1675 if (!torture_init_begin(torture_type, verbose, &torture_runnable)) 1676 return -EBUSY; 1677 1678 /* Process args and tell the world that the torturer is on the job. */ 1679 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) { 1680 cur_ops = torture_ops[i]; 1681 if (strcmp(torture_type, cur_ops->name) == 0) 1682 break; 1683 } 1684 if (i == ARRAY_SIZE(torture_ops)) { 1685 pr_alert("rcu-torture: invalid torture type: \"%s\"\n", 1686 torture_type); 1687 pr_alert("rcu-torture types:"); 1688 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) 1689 pr_alert(" %s", torture_ops[i]->name); 1690 pr_alert("\n"); 1691 torture_init_end(); 1692 return -EINVAL; 1693 } 1694 if (cur_ops->fqs == NULL && fqs_duration != 0) { 1695 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n"); 1696 fqs_duration = 0; 1697 } 1698 if (cur_ops->init) 1699 cur_ops->init(); /* no "goto unwind" prior to this point!!! */ 1700 1701 if (nreaders >= 0) { 1702 nrealreaders = nreaders; 1703 } else { 1704 nrealreaders = num_online_cpus() - 1; 1705 if (nrealreaders <= 0) 1706 nrealreaders = 1; 1707 } 1708 rcu_torture_print_module_parms(cur_ops, "Start of test"); 1709 1710 /* Set up the freelist. */ 1711 1712 INIT_LIST_HEAD(&rcu_torture_freelist); 1713 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) { 1714 rcu_tortures[i].rtort_mbtest = 0; 1715 list_add_tail(&rcu_tortures[i].rtort_free, 1716 &rcu_torture_freelist); 1717 } 1718 1719 /* Initialize the statistics so that each run gets its own numbers. */ 1720 1721 rcu_torture_current = NULL; 1722 rcu_torture_current_version = 0; 1723 atomic_set(&n_rcu_torture_alloc, 0); 1724 atomic_set(&n_rcu_torture_alloc_fail, 0); 1725 atomic_set(&n_rcu_torture_free, 0); 1726 atomic_set(&n_rcu_torture_mberror, 0); 1727 atomic_set(&n_rcu_torture_error, 0); 1728 n_rcu_torture_barrier_error = 0; 1729 n_rcu_torture_boost_ktrerror = 0; 1730 n_rcu_torture_boost_rterror = 0; 1731 n_rcu_torture_boost_failure = 0; 1732 n_rcu_torture_boosts = 0; 1733 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 1734 atomic_set(&rcu_torture_wcount[i], 0); 1735 for_each_possible_cpu(cpu) { 1736 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 1737 per_cpu(rcu_torture_count, cpu)[i] = 0; 1738 per_cpu(rcu_torture_batch, cpu)[i] = 0; 1739 } 1740 } 1741 1742 /* Start up the kthreads. */ 1743 1744 firsterr = torture_create_kthread(rcu_torture_writer, NULL, 1745 writer_task); 1746 if (firsterr) 1747 goto unwind; 1748 fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]), 1749 GFP_KERNEL); 1750 if (fakewriter_tasks == NULL) { 1751 VERBOSE_TOROUT_ERRSTRING("out of memory"); 1752 firsterr = -ENOMEM; 1753 goto unwind; 1754 } 1755 for (i = 0; i < nfakewriters; i++) { 1756 firsterr = torture_create_kthread(rcu_torture_fakewriter, 1757 NULL, fakewriter_tasks[i]); 1758 if (firsterr) 1759 goto unwind; 1760 } 1761 reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]), 1762 GFP_KERNEL); 1763 if (reader_tasks == NULL) { 1764 VERBOSE_TOROUT_ERRSTRING("out of memory"); 1765 firsterr = -ENOMEM; 1766 goto unwind; 1767 } 1768 for (i = 0; i < nrealreaders; i++) { 1769 firsterr = torture_create_kthread(rcu_torture_reader, NULL, 1770 reader_tasks[i]); 1771 if (firsterr) 1772 goto unwind; 1773 } 1774 if (stat_interval > 0) { 1775 firsterr = torture_create_kthread(rcu_torture_stats, NULL, 1776 stats_task); 1777 if (firsterr) 1778 goto unwind; 1779 } 1780 if (test_no_idle_hz) { 1781 firsterr = torture_shuffle_init(shuffle_interval * HZ); 1782 if (firsterr) 1783 goto unwind; 1784 } 1785 if (stutter < 0) 1786 stutter = 0; 1787 if (stutter) { 1788 firsterr = torture_stutter_init(stutter * HZ); 1789 if (firsterr) 1790 goto unwind; 1791 } 1792 if (fqs_duration < 0) 1793 fqs_duration = 0; 1794 if (fqs_duration) { 1795 /* Create the fqs thread */ 1796 firsterr = torture_create_kthread(rcu_torture_fqs, NULL, 1797 fqs_task); 1798 if (firsterr) 1799 goto unwind; 1800 } 1801 if (test_boost_interval < 1) 1802 test_boost_interval = 1; 1803 if (test_boost_duration < 2) 1804 test_boost_duration = 2; 1805 if ((test_boost == 1 && cur_ops->can_boost) || 1806 test_boost == 2) { 1807 1808 boost_starttime = jiffies + test_boost_interval * HZ; 1809 register_cpu_notifier(&rcutorture_cpu_nb); 1810 for_each_possible_cpu(i) { 1811 if (cpu_is_offline(i)) 1812 continue; /* Heuristic: CPU can go offline. */ 1813 firsterr = rcutorture_booster_init(i); 1814 if (firsterr) 1815 goto unwind; 1816 } 1817 } 1818 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup); 1819 if (firsterr) 1820 goto unwind; 1821 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval * HZ); 1822 if (firsterr) 1823 goto unwind; 1824 firsterr = rcu_torture_stall_init(); 1825 if (firsterr) 1826 goto unwind; 1827 firsterr = rcu_torture_barrier_init(); 1828 if (firsterr) 1829 goto unwind; 1830 if (object_debug) 1831 rcu_test_debug_objects(); 1832 if (cbflood_n_burst > 0) { 1833 /* Create the cbflood threads */ 1834 ncbflooders = (num_online_cpus() + 3) / 4; 1835 cbflood_task = kcalloc(ncbflooders, sizeof(*cbflood_task), 1836 GFP_KERNEL); 1837 if (!cbflood_task) { 1838 VERBOSE_TOROUT_ERRSTRING("out of memory"); 1839 firsterr = -ENOMEM; 1840 goto unwind; 1841 } 1842 for (i = 0; i < ncbflooders; i++) { 1843 firsterr = torture_create_kthread(rcu_torture_cbflood, 1844 NULL, 1845 cbflood_task[i]); 1846 if (firsterr) 1847 goto unwind; 1848 } 1849 } 1850 rcutorture_record_test_transition(); 1851 torture_init_end(); 1852 return 0; 1853 1854unwind: 1855 torture_init_end(); 1856 rcu_torture_cleanup(); 1857 return firsterr; 1858} 1859 1860module_init(rcu_torture_init); 1861module_exit(rcu_torture_cleanup); 1862