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 54 MODULE_LICENSE("GPL"); 55 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@joshtriplett.org>"); 56 57 58 torture_param(int, cbflood_inter_holdoff, HZ, 59 "Holdoff between floods (jiffies)"); 60 torture_param(int, cbflood_intra_holdoff, 1, 61 "Holdoff between bursts (jiffies)"); 62 torture_param(int, cbflood_n_burst, 3, "# bursts in flood, zero to disable"); 63 torture_param(int, cbflood_n_per_burst, 20000, 64 "# callbacks per burst in flood"); 65 torture_param(int, fqs_duration, 0, 66 "Duration of fqs bursts (us), 0 to disable"); 67 torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)"); 68 torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)"); 69 torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives"); 70 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives"); 71 torture_param(bool, gp_normal, false, 72 "Use normal (non-expedited) GP wait primitives"); 73 torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives"); 74 torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers"); 75 torture_param(int, n_barrier_cbs, 0, 76 "# of callbacks/kthreads for barrier testing"); 77 torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads"); 78 torture_param(int, nreaders, -1, "Number of RCU reader threads"); 79 torture_param(int, object_debug, 0, 80 "Enable debug-object double call_rcu() testing"); 81 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)"); 82 torture_param(int, onoff_interval, 0, 83 "Time between CPU hotplugs (s), 0=disable"); 84 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles"); 85 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable."); 86 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable."); 87 torture_param(int, stall_cpu_holdoff, 10, 88 "Time to wait before starting stall (s)."); 89 torture_param(int, stat_interval, 60, 90 "Number of seconds between stats printk()s"); 91 torture_param(int, stutter, 5, "Number of seconds to run/halt test"); 92 torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes."); 93 torture_param(int, test_boost_duration, 4, 94 "Duration of each boost test, seconds."); 95 torture_param(int, test_boost_interval, 7, 96 "Interval between boost tests, seconds."); 97 torture_param(bool, test_no_idle_hz, true, 98 "Test support for tickless idle CPUs"); 99 torture_param(bool, verbose, true, 100 "Enable verbose debugging printk()s"); 101 102 static char *torture_type = "rcu"; 103 module_param(torture_type, charp, 0444); 104 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, ...)"); 105 106 static int nrealreaders; 107 static int ncbflooders; 108 static struct task_struct *writer_task; 109 static struct task_struct **fakewriter_tasks; 110 static struct task_struct **reader_tasks; 111 static struct task_struct *stats_task; 112 static struct task_struct **cbflood_task; 113 static struct task_struct *fqs_task; 114 static struct task_struct *boost_tasks[NR_CPUS]; 115 static struct task_struct *stall_task; 116 static struct task_struct **barrier_cbs_tasks; 117 static struct task_struct *barrier_task; 118 119 #define RCU_TORTURE_PIPE_LEN 10 120 121 struct rcu_torture { 122 struct rcu_head rtort_rcu; 123 int rtort_pipe_count; 124 struct list_head rtort_free; 125 int rtort_mbtest; 126 }; 127 128 static LIST_HEAD(rcu_torture_freelist); 129 static struct rcu_torture __rcu *rcu_torture_current; 130 static unsigned long rcu_torture_current_version; 131 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN]; 132 static DEFINE_SPINLOCK(rcu_torture_lock); 133 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], 134 rcu_torture_count) = { 0 }; 135 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], 136 rcu_torture_batch) = { 0 }; 137 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1]; 138 static atomic_t n_rcu_torture_alloc; 139 static atomic_t n_rcu_torture_alloc_fail; 140 static atomic_t n_rcu_torture_free; 141 static atomic_t n_rcu_torture_mberror; 142 static atomic_t n_rcu_torture_error; 143 static long n_rcu_torture_barrier_error; 144 static long n_rcu_torture_boost_ktrerror; 145 static long n_rcu_torture_boost_rterror; 146 static long n_rcu_torture_boost_failure; 147 static long n_rcu_torture_boosts; 148 static long n_rcu_torture_timers; 149 static long n_barrier_attempts; 150 static long n_barrier_successes; 151 static atomic_long_t n_cbfloods; 152 static struct list_head rcu_torture_removed; 153 154 static 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 171 static int torture_runnable = RCUTORTURE_RUNNABLE_INIT; 172 module_param(torture_runnable, int, 0444); 173 MODULE_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 182 static 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 */ 189 static u64 notrace rcu_trace_clock_local(void) 190 { 191 return 0ULL; 192 } 193 #endif /* #else #ifdef CONFIG_RCU_TRACE */ 194 195 static unsigned long boost_starttime; /* jiffies of next boost test start. */ 196 static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */ 197 /* and boost task create/destroy. */ 198 static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */ 199 static bool barrier_phase; /* Test phase. */ 200 static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */ 201 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */ 202 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq); 203 204 /* 205 * Allocate an element from the rcu_tortures pool. 206 */ 207 static struct rcu_torture * 208 rcu_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 */ 228 static void 229 rcu_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 */ 240 241 struct 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 }; 262 263 static struct rcu_torture_ops *cur_ops; 264 265 /* 266 * Definitions for rcu torture testing. 267 */ 268 269 static int rcu_torture_read_lock(void) __acquires(RCU) 270 { 271 rcu_read_lock(); 272 return 0; 273 } 274 275 static 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 } 294 295 static 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 */ 303 static bool 304 rcu_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 */ 323 static void 324 rcu_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 } 338 339 static void 340 rcu_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 } 354 355 static unsigned long rcu_no_completed(void) 356 { 357 return 0; 358 } 359 360 static void rcu_torture_deferred_free(struct rcu_torture *p) 361 { 362 call_rcu(&p->rtort_rcu, rcu_torture_cb); 363 } 364 365 static void rcu_sync_torture_init(void) 366 { 367 INIT_LIST_HEAD(&rcu_torture_removed); 368 } 369 370 static 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 */ 395 396 static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH) 397 { 398 rcu_read_lock_bh(); 399 return 0; 400 } 401 402 static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH) 403 { 404 rcu_read_unlock_bh(); 405 } 406 407 static void rcu_bh_torture_deferred_free(struct rcu_torture *p) 408 { 409 call_rcu_bh(&p->rtort_rcu, rcu_torture_cb); 410 } 411 412 static 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 */ 438 static 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 } 443 444 static void synchronize_rcu_busted(void) 445 { 446 /* This is a deliberate bug for testing purposes only! */ 447 } 448 449 static void 450 call_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 } 455 456 static 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 */ 478 479 DEFINE_STATIC_SRCU(srcu_ctl); 480 481 static int srcu_torture_read_lock(void) __acquires(&srcu_ctl) 482 { 483 return srcu_read_lock(&srcu_ctl); 484 } 485 486 static 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 } 501 502 static void srcu_torture_read_unlock(int idx) __releases(&srcu_ctl) 503 { 504 srcu_read_unlock(&srcu_ctl, idx); 505 } 506 507 static unsigned long srcu_torture_completed(void) 508 { 509 return srcu_batches_completed(&srcu_ctl); 510 } 511 512 static void srcu_torture_deferred_free(struct rcu_torture *rp) 513 { 514 call_srcu(&srcu_ctl, &rp->rtort_rcu, rcu_torture_cb); 515 } 516 517 static void srcu_torture_synchronize(void) 518 { 519 synchronize_srcu(&srcu_ctl); 520 } 521 522 static void srcu_torture_call(struct rcu_head *head, 523 void (*func)(struct rcu_head *head)) 524 { 525 call_srcu(&srcu_ctl, head, func); 526 } 527 528 static void srcu_torture_barrier(void) 529 { 530 srcu_barrier(&srcu_ctl); 531 } 532 533 static 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 } 549 550 static void srcu_torture_synchronize_expedited(void) 551 { 552 synchronize_srcu_expedited(&srcu_ctl); 553 } 554 555 static 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 */ 575 576 static int sched_torture_read_lock(void) 577 { 578 preempt_disable(); 579 return 0; 580 } 581 582 static void sched_torture_read_unlock(int idx) 583 { 584 preempt_enable(); 585 } 586 587 static void rcu_sched_torture_deferred_free(struct rcu_torture *p) 588 { 589 call_rcu_sched(&p->rtort_rcu, rcu_torture_cb); 590 } 591 592 static 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 */ 616 617 static int tasks_torture_read_lock(void) 618 { 619 return 0; 620 } 621 622 static void tasks_torture_read_unlock(int idx) 623 { 624 } 625 626 static void rcu_tasks_torture_deferred_free(struct rcu_torture *p) 627 { 628 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb); 629 } 630 631 static 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 */ 664 665 struct rcu_boost_inflight { 666 struct rcu_head rcu; 667 int inflight; 668 }; 669 670 static 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 } 678 679 static 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. */ 750 checkwait: 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 } 763 764 static 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 */ 773 static int 774 rcu_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 */ 822 static int 823 rcu_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 */ 853 static int 854 rcu_torture_writer(void *arg) 855 { 856 unsigned long gp_snap; 857 bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal; 858 bool gp_sync1 = gp_sync; 859 int i; 860 struct rcu_torture *rp; 861 struct rcu_torture *old_rp; 862 static DEFINE_TORTURE_RANDOM(rand); 863 int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC, 864 RTWS_COND_GET, RTWS_SYNC }; 865 int nsynctypes = 0; 866 867 VERBOSE_TOROUT_STRING("rcu_torture_writer task started"); 868 869 /* Initialize synctype[] array. If none set, take default. */ 870 if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync) 871 gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true; 872 if (gp_cond1 && cur_ops->get_state && cur_ops->cond_sync) 873 synctype[nsynctypes++] = RTWS_COND_GET; 874 else if (gp_cond && (!cur_ops->get_state || !cur_ops->cond_sync)) 875 pr_alert("rcu_torture_writer: gp_cond without primitives.\n"); 876 if (gp_exp1 && cur_ops->exp_sync) 877 synctype[nsynctypes++] = RTWS_EXP_SYNC; 878 else if (gp_exp && !cur_ops->exp_sync) 879 pr_alert("rcu_torture_writer: gp_exp without primitives.\n"); 880 if (gp_normal1 && cur_ops->deferred_free) 881 synctype[nsynctypes++] = RTWS_DEF_FREE; 882 else if (gp_normal && !cur_ops->deferred_free) 883 pr_alert("rcu_torture_writer: gp_normal without primitives.\n"); 884 if (gp_sync1 && cur_ops->sync) 885 synctype[nsynctypes++] = RTWS_SYNC; 886 else if (gp_sync && !cur_ops->sync) 887 pr_alert("rcu_torture_writer: gp_sync without primitives.\n"); 888 if (WARN_ONCE(nsynctypes == 0, 889 "rcu_torture_writer: No update-side primitives.\n")) { 890 /* 891 * No updates primitives, so don't try updating. 892 * The resulting test won't be testing much, hence the 893 * above WARN_ONCE(). 894 */ 895 rcu_torture_writer_state = RTWS_STOPPING; 896 torture_kthread_stopping("rcu_torture_writer"); 897 } 898 899 do { 900 rcu_torture_writer_state = RTWS_FIXED_DELAY; 901 schedule_timeout_uninterruptible(1); 902 rp = rcu_torture_alloc(); 903 if (rp == NULL) 904 continue; 905 rp->rtort_pipe_count = 0; 906 rcu_torture_writer_state = RTWS_DELAY; 907 udelay(torture_random(&rand) & 0x3ff); 908 rcu_torture_writer_state = RTWS_REPLACE; 909 old_rp = rcu_dereference_check(rcu_torture_current, 910 current == writer_task); 911 rp->rtort_mbtest = 1; 912 rcu_assign_pointer(rcu_torture_current, rp); 913 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */ 914 if (old_rp) { 915 i = old_rp->rtort_pipe_count; 916 if (i > RCU_TORTURE_PIPE_LEN) 917 i = RCU_TORTURE_PIPE_LEN; 918 atomic_inc(&rcu_torture_wcount[i]); 919 old_rp->rtort_pipe_count++; 920 switch (synctype[torture_random(&rand) % nsynctypes]) { 921 case RTWS_DEF_FREE: 922 rcu_torture_writer_state = RTWS_DEF_FREE; 923 cur_ops->deferred_free(old_rp); 924 break; 925 case RTWS_EXP_SYNC: 926 rcu_torture_writer_state = RTWS_EXP_SYNC; 927 cur_ops->exp_sync(); 928 rcu_torture_pipe_update(old_rp); 929 break; 930 case RTWS_COND_GET: 931 rcu_torture_writer_state = RTWS_COND_GET; 932 gp_snap = cur_ops->get_state(); 933 i = torture_random(&rand) % 16; 934 if (i != 0) 935 schedule_timeout_interruptible(i); 936 udelay(torture_random(&rand) % 1000); 937 rcu_torture_writer_state = RTWS_COND_SYNC; 938 cur_ops->cond_sync(gp_snap); 939 rcu_torture_pipe_update(old_rp); 940 break; 941 case RTWS_SYNC: 942 rcu_torture_writer_state = RTWS_SYNC; 943 cur_ops->sync(); 944 rcu_torture_pipe_update(old_rp); 945 break; 946 default: 947 WARN_ON_ONCE(1); 948 break; 949 } 950 } 951 rcutorture_record_progress(++rcu_torture_current_version); 952 rcu_torture_writer_state = RTWS_STUTTER; 953 stutter_wait("rcu_torture_writer"); 954 } while (!torture_must_stop()); 955 rcu_torture_writer_state = RTWS_STOPPING; 956 torture_kthread_stopping("rcu_torture_writer"); 957 return 0; 958 } 959 960 /* 961 * RCU torture fake writer kthread. Repeatedly calls sync, with a random 962 * delay between calls. 963 */ 964 static int 965 rcu_torture_fakewriter(void *arg) 966 { 967 DEFINE_TORTURE_RANDOM(rand); 968 969 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started"); 970 set_user_nice(current, MAX_NICE); 971 972 do { 973 schedule_timeout_uninterruptible(1 + torture_random(&rand)%10); 974 udelay(torture_random(&rand) & 0x3ff); 975 if (cur_ops->cb_barrier != NULL && 976 torture_random(&rand) % (nfakewriters * 8) == 0) { 977 cur_ops->cb_barrier(); 978 } else if (gp_normal == gp_exp) { 979 if (torture_random(&rand) & 0x80) 980 cur_ops->sync(); 981 else 982 cur_ops->exp_sync(); 983 } else if (gp_normal) { 984 cur_ops->sync(); 985 } else { 986 cur_ops->exp_sync(); 987 } 988 stutter_wait("rcu_torture_fakewriter"); 989 } while (!torture_must_stop()); 990 991 torture_kthread_stopping("rcu_torture_fakewriter"); 992 return 0; 993 } 994 995 static void rcutorture_trace_dump(void) 996 { 997 static atomic_t beenhere = ATOMIC_INIT(0); 998 999 if (atomic_read(&beenhere)) 1000 return; 1001 if (atomic_xchg(&beenhere, 1) != 0) 1002 return; 1003 ftrace_dump(DUMP_ALL); 1004 } 1005 1006 /* 1007 * RCU torture reader from timer handler. Dereferences rcu_torture_current, 1008 * incrementing the corresponding element of the pipeline array. The 1009 * counter in the element should never be greater than 1, otherwise, the 1010 * RCU implementation is broken. 1011 */ 1012 static void rcu_torture_timer(unsigned long unused) 1013 { 1014 int idx; 1015 unsigned long started; 1016 unsigned long completed; 1017 static DEFINE_TORTURE_RANDOM(rand); 1018 static DEFINE_SPINLOCK(rand_lock); 1019 struct rcu_torture *p; 1020 int pipe_count; 1021 unsigned long long ts; 1022 1023 idx = cur_ops->readlock(); 1024 if (cur_ops->started) 1025 started = cur_ops->started(); 1026 else 1027 started = cur_ops->completed(); 1028 ts = rcu_trace_clock_local(); 1029 p = rcu_dereference_check(rcu_torture_current, 1030 rcu_read_lock_bh_held() || 1031 rcu_read_lock_sched_held() || 1032 srcu_read_lock_held(&srcu_ctl)); 1033 if (p == NULL) { 1034 /* Leave because rcu_torture_writer is not yet underway */ 1035 cur_ops->readunlock(idx); 1036 return; 1037 } 1038 if (p->rtort_mbtest == 0) 1039 atomic_inc(&n_rcu_torture_mberror); 1040 spin_lock(&rand_lock); 1041 cur_ops->read_delay(&rand); 1042 n_rcu_torture_timers++; 1043 spin_unlock(&rand_lock); 1044 preempt_disable(); 1045 pipe_count = p->rtort_pipe_count; 1046 if (pipe_count > RCU_TORTURE_PIPE_LEN) { 1047 /* Should not happen, but... */ 1048 pipe_count = RCU_TORTURE_PIPE_LEN; 1049 } 1050 completed = cur_ops->completed(); 1051 if (pipe_count > 1) { 1052 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, ts, 1053 started, completed); 1054 rcutorture_trace_dump(); 1055 } 1056 __this_cpu_inc(rcu_torture_count[pipe_count]); 1057 completed = completed - started; 1058 if (cur_ops->started) 1059 completed++; 1060 if (completed > RCU_TORTURE_PIPE_LEN) { 1061 /* Should not happen, but... */ 1062 completed = RCU_TORTURE_PIPE_LEN; 1063 } 1064 __this_cpu_inc(rcu_torture_batch[completed]); 1065 preempt_enable(); 1066 cur_ops->readunlock(idx); 1067 } 1068 1069 /* 1070 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current, 1071 * incrementing the corresponding element of the pipeline array. The 1072 * counter in the element should never be greater than 1, otherwise, the 1073 * RCU implementation is broken. 1074 */ 1075 static int 1076 rcu_torture_reader(void *arg) 1077 { 1078 unsigned long started; 1079 unsigned long completed; 1080 int idx; 1081 DEFINE_TORTURE_RANDOM(rand); 1082 struct rcu_torture *p; 1083 int pipe_count; 1084 struct timer_list t; 1085 unsigned long long ts; 1086 1087 VERBOSE_TOROUT_STRING("rcu_torture_reader task started"); 1088 set_user_nice(current, MAX_NICE); 1089 if (irqreader && cur_ops->irq_capable) 1090 setup_timer_on_stack(&t, rcu_torture_timer, 0); 1091 1092 do { 1093 if (irqreader && cur_ops->irq_capable) { 1094 if (!timer_pending(&t)) 1095 mod_timer(&t, jiffies + 1); 1096 } 1097 idx = cur_ops->readlock(); 1098 if (cur_ops->started) 1099 started = cur_ops->started(); 1100 else 1101 started = cur_ops->completed(); 1102 ts = rcu_trace_clock_local(); 1103 p = rcu_dereference_check(rcu_torture_current, 1104 rcu_read_lock_bh_held() || 1105 rcu_read_lock_sched_held() || 1106 srcu_read_lock_held(&srcu_ctl)); 1107 if (p == NULL) { 1108 /* Wait for rcu_torture_writer to get underway */ 1109 cur_ops->readunlock(idx); 1110 schedule_timeout_interruptible(HZ); 1111 continue; 1112 } 1113 if (p->rtort_mbtest == 0) 1114 atomic_inc(&n_rcu_torture_mberror); 1115 cur_ops->read_delay(&rand); 1116 preempt_disable(); 1117 pipe_count = p->rtort_pipe_count; 1118 if (pipe_count > RCU_TORTURE_PIPE_LEN) { 1119 /* Should not happen, but... */ 1120 pipe_count = RCU_TORTURE_PIPE_LEN; 1121 } 1122 completed = cur_ops->completed(); 1123 if (pipe_count > 1) { 1124 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, 1125 ts, started, completed); 1126 rcutorture_trace_dump(); 1127 } 1128 __this_cpu_inc(rcu_torture_count[pipe_count]); 1129 completed = completed - started; 1130 if (cur_ops->started) 1131 completed++; 1132 if (completed > RCU_TORTURE_PIPE_LEN) { 1133 /* Should not happen, but... */ 1134 completed = RCU_TORTURE_PIPE_LEN; 1135 } 1136 __this_cpu_inc(rcu_torture_batch[completed]); 1137 preempt_enable(); 1138 cur_ops->readunlock(idx); 1139 cond_resched_rcu_qs(); 1140 stutter_wait("rcu_torture_reader"); 1141 } while (!torture_must_stop()); 1142 if (irqreader && cur_ops->irq_capable) { 1143 del_timer_sync(&t); 1144 destroy_timer_on_stack(&t); 1145 } 1146 torture_kthread_stopping("rcu_torture_reader"); 1147 return 0; 1148 } 1149 1150 /* 1151 * Print torture statistics. Caller must ensure that there is only 1152 * one call to this function at a given time!!! This is normally 1153 * accomplished by relying on the module system to only have one copy 1154 * of the module loaded, and then by giving the rcu_torture_stats 1155 * kthread full control (or the init/cleanup functions when rcu_torture_stats 1156 * thread is not running). 1157 */ 1158 static void 1159 rcu_torture_stats_print(void) 1160 { 1161 int cpu; 1162 int i; 1163 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; 1164 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; 1165 static unsigned long rtcv_snap = ULONG_MAX; 1166 1167 for_each_possible_cpu(cpu) { 1168 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 1169 pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i]; 1170 batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i]; 1171 } 1172 } 1173 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) { 1174 if (pipesummary[i] != 0) 1175 break; 1176 } 1177 1178 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1179 pr_cont("rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ", 1180 rcu_torture_current, 1181 rcu_torture_current_version, 1182 list_empty(&rcu_torture_freelist), 1183 atomic_read(&n_rcu_torture_alloc), 1184 atomic_read(&n_rcu_torture_alloc_fail), 1185 atomic_read(&n_rcu_torture_free)); 1186 pr_cont("rtmbe: %d rtbke: %ld rtbre: %ld ", 1187 atomic_read(&n_rcu_torture_mberror), 1188 n_rcu_torture_boost_ktrerror, 1189 n_rcu_torture_boost_rterror); 1190 pr_cont("rtbf: %ld rtb: %ld nt: %ld ", 1191 n_rcu_torture_boost_failure, 1192 n_rcu_torture_boosts, 1193 n_rcu_torture_timers); 1194 torture_onoff_stats(); 1195 pr_cont("barrier: %ld/%ld:%ld ", 1196 n_barrier_successes, 1197 n_barrier_attempts, 1198 n_rcu_torture_barrier_error); 1199 pr_cont("cbflood: %ld\n", atomic_long_read(&n_cbfloods)); 1200 1201 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1202 if (atomic_read(&n_rcu_torture_mberror) != 0 || 1203 n_rcu_torture_barrier_error != 0 || 1204 n_rcu_torture_boost_ktrerror != 0 || 1205 n_rcu_torture_boost_rterror != 0 || 1206 n_rcu_torture_boost_failure != 0 || 1207 i > 1) { 1208 pr_cont("%s", "!!! "); 1209 atomic_inc(&n_rcu_torture_error); 1210 WARN_ON_ONCE(1); 1211 } 1212 pr_cont("Reader Pipe: "); 1213 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 1214 pr_cont(" %ld", pipesummary[i]); 1215 pr_cont("\n"); 1216 1217 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1218 pr_cont("Reader Batch: "); 1219 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 1220 pr_cont(" %ld", batchsummary[i]); 1221 pr_cont("\n"); 1222 1223 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1224 pr_cont("Free-Block Circulation: "); 1225 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 1226 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i])); 1227 } 1228 pr_cont("\n"); 1229 1230 if (cur_ops->stats) 1231 cur_ops->stats(); 1232 if (rtcv_snap == rcu_torture_current_version && 1233 rcu_torture_current != NULL) { 1234 int __maybe_unused flags; 1235 unsigned long __maybe_unused gpnum; 1236 unsigned long __maybe_unused completed; 1237 1238 rcutorture_get_gp_data(cur_ops->ttype, 1239 &flags, &gpnum, &completed); 1240 pr_alert("??? Writer stall state %d g%lu c%lu f%#x\n", 1241 rcu_torture_writer_state, 1242 gpnum, completed, flags); 1243 show_rcu_gp_kthreads(); 1244 rcutorture_trace_dump(); 1245 } 1246 rtcv_snap = rcu_torture_current_version; 1247 } 1248 1249 /* 1250 * Periodically prints torture statistics, if periodic statistics printing 1251 * was specified via the stat_interval module parameter. 1252 */ 1253 static int 1254 rcu_torture_stats(void *arg) 1255 { 1256 VERBOSE_TOROUT_STRING("rcu_torture_stats task started"); 1257 do { 1258 schedule_timeout_interruptible(stat_interval * HZ); 1259 rcu_torture_stats_print(); 1260 torture_shutdown_absorb("rcu_torture_stats"); 1261 } while (!torture_must_stop()); 1262 torture_kthread_stopping("rcu_torture_stats"); 1263 return 0; 1264 } 1265 1266 static inline void 1267 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag) 1268 { 1269 pr_alert("%s" TORTURE_FLAG 1270 "--- %s: nreaders=%d nfakewriters=%d " 1271 "stat_interval=%d verbose=%d test_no_idle_hz=%d " 1272 "shuffle_interval=%d stutter=%d irqreader=%d " 1273 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d " 1274 "test_boost=%d/%d test_boost_interval=%d " 1275 "test_boost_duration=%d shutdown_secs=%d " 1276 "stall_cpu=%d stall_cpu_holdoff=%d " 1277 "n_barrier_cbs=%d " 1278 "onoff_interval=%d onoff_holdoff=%d\n", 1279 torture_type, tag, nrealreaders, nfakewriters, 1280 stat_interval, verbose, test_no_idle_hz, shuffle_interval, 1281 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter, 1282 test_boost, cur_ops->can_boost, 1283 test_boost_interval, test_boost_duration, shutdown_secs, 1284 stall_cpu, stall_cpu_holdoff, 1285 n_barrier_cbs, 1286 onoff_interval, onoff_holdoff); 1287 } 1288 1289 static void rcutorture_booster_cleanup(int cpu) 1290 { 1291 struct task_struct *t; 1292 1293 if (boost_tasks[cpu] == NULL) 1294 return; 1295 mutex_lock(&boost_mutex); 1296 t = boost_tasks[cpu]; 1297 boost_tasks[cpu] = NULL; 1298 mutex_unlock(&boost_mutex); 1299 1300 /* This must be outside of the mutex, otherwise deadlock! */ 1301 torture_stop_kthread(rcu_torture_boost, t); 1302 } 1303 1304 static int rcutorture_booster_init(int cpu) 1305 { 1306 int retval; 1307 1308 if (boost_tasks[cpu] != NULL) 1309 return 0; /* Already created, nothing more to do. */ 1310 1311 /* Don't allow time recalculation while creating a new task. */ 1312 mutex_lock(&boost_mutex); 1313 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task"); 1314 boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL, 1315 cpu_to_node(cpu), 1316 "rcu_torture_boost"); 1317 if (IS_ERR(boost_tasks[cpu])) { 1318 retval = PTR_ERR(boost_tasks[cpu]); 1319 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed"); 1320 n_rcu_torture_boost_ktrerror++; 1321 boost_tasks[cpu] = NULL; 1322 mutex_unlock(&boost_mutex); 1323 return retval; 1324 } 1325 kthread_bind(boost_tasks[cpu], cpu); 1326 wake_up_process(boost_tasks[cpu]); 1327 mutex_unlock(&boost_mutex); 1328 return 0; 1329 } 1330 1331 /* 1332 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then 1333 * induces a CPU stall for the time specified by stall_cpu. 1334 */ 1335 static int rcu_torture_stall(void *args) 1336 { 1337 unsigned long stop_at; 1338 1339 VERBOSE_TOROUT_STRING("rcu_torture_stall task started"); 1340 if (stall_cpu_holdoff > 0) { 1341 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff"); 1342 schedule_timeout_interruptible(stall_cpu_holdoff * HZ); 1343 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff"); 1344 } 1345 if (!kthread_should_stop()) { 1346 stop_at = get_seconds() + stall_cpu; 1347 /* RCU CPU stall is expected behavior in following code. */ 1348 pr_alert("rcu_torture_stall start.\n"); 1349 rcu_read_lock(); 1350 preempt_disable(); 1351 while (ULONG_CMP_LT(get_seconds(), stop_at)) 1352 continue; /* Induce RCU CPU stall warning. */ 1353 preempt_enable(); 1354 rcu_read_unlock(); 1355 pr_alert("rcu_torture_stall end.\n"); 1356 } 1357 torture_shutdown_absorb("rcu_torture_stall"); 1358 while (!kthread_should_stop()) 1359 schedule_timeout_interruptible(10 * HZ); 1360 return 0; 1361 } 1362 1363 /* Spawn CPU-stall kthread, if stall_cpu specified. */ 1364 static int __init rcu_torture_stall_init(void) 1365 { 1366 if (stall_cpu <= 0) 1367 return 0; 1368 return torture_create_kthread(rcu_torture_stall, NULL, stall_task); 1369 } 1370 1371 /* Callback function for RCU barrier testing. */ 1372 static void rcu_torture_barrier_cbf(struct rcu_head *rcu) 1373 { 1374 atomic_inc(&barrier_cbs_invoked); 1375 } 1376 1377 /* kthread function to register callbacks used to test RCU barriers. */ 1378 static int rcu_torture_barrier_cbs(void *arg) 1379 { 1380 long myid = (long)arg; 1381 bool lastphase = 0; 1382 bool newphase; 1383 struct rcu_head rcu; 1384 1385 init_rcu_head_on_stack(&rcu); 1386 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started"); 1387 set_user_nice(current, MAX_NICE); 1388 do { 1389 wait_event(barrier_cbs_wq[myid], 1390 (newphase = 1391 ACCESS_ONCE(barrier_phase)) != lastphase || 1392 torture_must_stop()); 1393 lastphase = newphase; 1394 smp_mb(); /* ensure barrier_phase load before ->call(). */ 1395 if (torture_must_stop()) 1396 break; 1397 cur_ops->call(&rcu, rcu_torture_barrier_cbf); 1398 if (atomic_dec_and_test(&barrier_cbs_count)) 1399 wake_up(&barrier_wq); 1400 } while (!torture_must_stop()); 1401 if (cur_ops->cb_barrier != NULL) 1402 cur_ops->cb_barrier(); 1403 destroy_rcu_head_on_stack(&rcu); 1404 torture_kthread_stopping("rcu_torture_barrier_cbs"); 1405 return 0; 1406 } 1407 1408 /* kthread function to drive and coordinate RCU barrier testing. */ 1409 static int rcu_torture_barrier(void *arg) 1410 { 1411 int i; 1412 1413 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting"); 1414 do { 1415 atomic_set(&barrier_cbs_invoked, 0); 1416 atomic_set(&barrier_cbs_count, n_barrier_cbs); 1417 smp_mb(); /* Ensure barrier_phase after prior assignments. */ 1418 barrier_phase = !barrier_phase; 1419 for (i = 0; i < n_barrier_cbs; i++) 1420 wake_up(&barrier_cbs_wq[i]); 1421 wait_event(barrier_wq, 1422 atomic_read(&barrier_cbs_count) == 0 || 1423 torture_must_stop()); 1424 if (torture_must_stop()) 1425 break; 1426 n_barrier_attempts++; 1427 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */ 1428 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) { 1429 n_rcu_torture_barrier_error++; 1430 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n", 1431 atomic_read(&barrier_cbs_invoked), 1432 n_barrier_cbs); 1433 WARN_ON_ONCE(1); 1434 } 1435 n_barrier_successes++; 1436 schedule_timeout_interruptible(HZ / 10); 1437 } while (!torture_must_stop()); 1438 torture_kthread_stopping("rcu_torture_barrier"); 1439 return 0; 1440 } 1441 1442 /* Initialize RCU barrier testing. */ 1443 static int rcu_torture_barrier_init(void) 1444 { 1445 int i; 1446 int ret; 1447 1448 if (n_barrier_cbs == 0) 1449 return 0; 1450 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) { 1451 pr_alert("%s" TORTURE_FLAG 1452 " Call or barrier ops missing for %s,\n", 1453 torture_type, cur_ops->name); 1454 pr_alert("%s" TORTURE_FLAG 1455 " RCU barrier testing omitted from run.\n", 1456 torture_type); 1457 return 0; 1458 } 1459 atomic_set(&barrier_cbs_count, 0); 1460 atomic_set(&barrier_cbs_invoked, 0); 1461 barrier_cbs_tasks = 1462 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_tasks[0]), 1463 GFP_KERNEL); 1464 barrier_cbs_wq = 1465 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_wq[0]), 1466 GFP_KERNEL); 1467 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq) 1468 return -ENOMEM; 1469 for (i = 0; i < n_barrier_cbs; i++) { 1470 init_waitqueue_head(&barrier_cbs_wq[i]); 1471 ret = torture_create_kthread(rcu_torture_barrier_cbs, 1472 (void *)(long)i, 1473 barrier_cbs_tasks[i]); 1474 if (ret) 1475 return ret; 1476 } 1477 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task); 1478 } 1479 1480 /* Clean up after RCU barrier testing. */ 1481 static void rcu_torture_barrier_cleanup(void) 1482 { 1483 int i; 1484 1485 torture_stop_kthread(rcu_torture_barrier, barrier_task); 1486 if (barrier_cbs_tasks != NULL) { 1487 for (i = 0; i < n_barrier_cbs; i++) 1488 torture_stop_kthread(rcu_torture_barrier_cbs, 1489 barrier_cbs_tasks[i]); 1490 kfree(barrier_cbs_tasks); 1491 barrier_cbs_tasks = NULL; 1492 } 1493 if (barrier_cbs_wq != NULL) { 1494 kfree(barrier_cbs_wq); 1495 barrier_cbs_wq = NULL; 1496 } 1497 } 1498 1499 static int rcutorture_cpu_notify(struct notifier_block *self, 1500 unsigned long action, void *hcpu) 1501 { 1502 long cpu = (long)hcpu; 1503 1504 switch (action) { 1505 case CPU_ONLINE: 1506 case CPU_DOWN_FAILED: 1507 (void)rcutorture_booster_init(cpu); 1508 break; 1509 case CPU_DOWN_PREPARE: 1510 rcutorture_booster_cleanup(cpu); 1511 break; 1512 default: 1513 break; 1514 } 1515 return NOTIFY_OK; 1516 } 1517 1518 static struct notifier_block rcutorture_cpu_nb = { 1519 .notifier_call = rcutorture_cpu_notify, 1520 }; 1521 1522 static void 1523 rcu_torture_cleanup(void) 1524 { 1525 int i; 1526 1527 rcutorture_record_test_transition(); 1528 if (torture_cleanup_begin()) { 1529 if (cur_ops->cb_barrier != NULL) 1530 cur_ops->cb_barrier(); 1531 return; 1532 } 1533 1534 rcu_torture_barrier_cleanup(); 1535 torture_stop_kthread(rcu_torture_stall, stall_task); 1536 torture_stop_kthread(rcu_torture_writer, writer_task); 1537 1538 if (reader_tasks) { 1539 for (i = 0; i < nrealreaders; i++) 1540 torture_stop_kthread(rcu_torture_reader, 1541 reader_tasks[i]); 1542 kfree(reader_tasks); 1543 } 1544 rcu_torture_current = NULL; 1545 1546 if (fakewriter_tasks) { 1547 for (i = 0; i < nfakewriters; i++) { 1548 torture_stop_kthread(rcu_torture_fakewriter, 1549 fakewriter_tasks[i]); 1550 } 1551 kfree(fakewriter_tasks); 1552 fakewriter_tasks = NULL; 1553 } 1554 1555 torture_stop_kthread(rcu_torture_stats, stats_task); 1556 torture_stop_kthread(rcu_torture_fqs, fqs_task); 1557 for (i = 0; i < ncbflooders; i++) 1558 torture_stop_kthread(rcu_torture_cbflood, cbflood_task[i]); 1559 if ((test_boost == 1 && cur_ops->can_boost) || 1560 test_boost == 2) { 1561 unregister_cpu_notifier(&rcutorture_cpu_nb); 1562 for_each_possible_cpu(i) 1563 rcutorture_booster_cleanup(i); 1564 } 1565 1566 /* Wait for all RCU callbacks to fire. */ 1567 1568 if (cur_ops->cb_barrier != NULL) 1569 cur_ops->cb_barrier(); 1570 1571 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */ 1572 1573 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error) 1574 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE"); 1575 else if (torture_onoff_failures()) 1576 rcu_torture_print_module_parms(cur_ops, 1577 "End of test: RCU_HOTPLUG"); 1578 else 1579 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS"); 1580 torture_cleanup_end(); 1581 } 1582 1583 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD 1584 static void rcu_torture_leak_cb(struct rcu_head *rhp) 1585 { 1586 } 1587 1588 static void rcu_torture_err_cb(struct rcu_head *rhp) 1589 { 1590 /* 1591 * This -might- happen due to race conditions, but is unlikely. 1592 * The scenario that leads to this happening is that the 1593 * first of the pair of duplicate callbacks is queued, 1594 * someone else starts a grace period that includes that 1595 * callback, then the second of the pair must wait for the 1596 * next grace period. Unlikely, but can happen. If it 1597 * does happen, the debug-objects subsystem won't have splatted. 1598 */ 1599 pr_alert("rcutorture: duplicated callback was invoked.\n"); 1600 } 1601 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 1602 1603 /* 1604 * Verify that double-free causes debug-objects to complain, but only 1605 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test 1606 * cannot be carried out. 1607 */ 1608 static void rcu_test_debug_objects(void) 1609 { 1610 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD 1611 struct rcu_head rh1; 1612 struct rcu_head rh2; 1613 1614 init_rcu_head_on_stack(&rh1); 1615 init_rcu_head_on_stack(&rh2); 1616 pr_alert("rcutorture: WARN: Duplicate call_rcu() test starting.\n"); 1617 1618 /* Try to queue the rh2 pair of callbacks for the same grace period. */ 1619 preempt_disable(); /* Prevent preemption from interrupting test. */ 1620 rcu_read_lock(); /* Make it impossible to finish a grace period. */ 1621 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */ 1622 local_irq_disable(); /* Make it harder to start a new grace period. */ 1623 call_rcu(&rh2, rcu_torture_leak_cb); 1624 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */ 1625 local_irq_enable(); 1626 rcu_read_unlock(); 1627 preempt_enable(); 1628 1629 /* Wait for them all to get done so we can safely return. */ 1630 rcu_barrier(); 1631 pr_alert("rcutorture: WARN: Duplicate call_rcu() test complete.\n"); 1632 destroy_rcu_head_on_stack(&rh1); 1633 destroy_rcu_head_on_stack(&rh2); 1634 #else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 1635 pr_alert("rcutorture: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n"); 1636 #endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 1637 } 1638 1639 static int __init 1640 rcu_torture_init(void) 1641 { 1642 int i; 1643 int cpu; 1644 int firsterr = 0; 1645 static struct rcu_torture_ops *torture_ops[] = { 1646 &rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &sched_ops, 1647 RCUTORTURE_TASKS_OPS 1648 }; 1649 1650 if (!torture_init_begin(torture_type, verbose, &torture_runnable)) 1651 return -EBUSY; 1652 1653 /* Process args and tell the world that the torturer is on the job. */ 1654 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) { 1655 cur_ops = torture_ops[i]; 1656 if (strcmp(torture_type, cur_ops->name) == 0) 1657 break; 1658 } 1659 if (i == ARRAY_SIZE(torture_ops)) { 1660 pr_alert("rcu-torture: invalid torture type: \"%s\"\n", 1661 torture_type); 1662 pr_alert("rcu-torture types:"); 1663 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) 1664 pr_alert(" %s", torture_ops[i]->name); 1665 pr_alert("\n"); 1666 torture_init_end(); 1667 return -EINVAL; 1668 } 1669 if (cur_ops->fqs == NULL && fqs_duration != 0) { 1670 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n"); 1671 fqs_duration = 0; 1672 } 1673 if (cur_ops->init) 1674 cur_ops->init(); /* no "goto unwind" prior to this point!!! */ 1675 1676 if (nreaders >= 0) { 1677 nrealreaders = nreaders; 1678 } else { 1679 nrealreaders = num_online_cpus() - 1; 1680 if (nrealreaders <= 0) 1681 nrealreaders = 1; 1682 } 1683 rcu_torture_print_module_parms(cur_ops, "Start of test"); 1684 1685 /* Set up the freelist. */ 1686 1687 INIT_LIST_HEAD(&rcu_torture_freelist); 1688 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) { 1689 rcu_tortures[i].rtort_mbtest = 0; 1690 list_add_tail(&rcu_tortures[i].rtort_free, 1691 &rcu_torture_freelist); 1692 } 1693 1694 /* Initialize the statistics so that each run gets its own numbers. */ 1695 1696 rcu_torture_current = NULL; 1697 rcu_torture_current_version = 0; 1698 atomic_set(&n_rcu_torture_alloc, 0); 1699 atomic_set(&n_rcu_torture_alloc_fail, 0); 1700 atomic_set(&n_rcu_torture_free, 0); 1701 atomic_set(&n_rcu_torture_mberror, 0); 1702 atomic_set(&n_rcu_torture_error, 0); 1703 n_rcu_torture_barrier_error = 0; 1704 n_rcu_torture_boost_ktrerror = 0; 1705 n_rcu_torture_boost_rterror = 0; 1706 n_rcu_torture_boost_failure = 0; 1707 n_rcu_torture_boosts = 0; 1708 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 1709 atomic_set(&rcu_torture_wcount[i], 0); 1710 for_each_possible_cpu(cpu) { 1711 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 1712 per_cpu(rcu_torture_count, cpu)[i] = 0; 1713 per_cpu(rcu_torture_batch, cpu)[i] = 0; 1714 } 1715 } 1716 1717 /* Start up the kthreads. */ 1718 1719 firsterr = torture_create_kthread(rcu_torture_writer, NULL, 1720 writer_task); 1721 if (firsterr) 1722 goto unwind; 1723 fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]), 1724 GFP_KERNEL); 1725 if (fakewriter_tasks == NULL) { 1726 VERBOSE_TOROUT_ERRSTRING("out of memory"); 1727 firsterr = -ENOMEM; 1728 goto unwind; 1729 } 1730 for (i = 0; i < nfakewriters; i++) { 1731 firsterr = torture_create_kthread(rcu_torture_fakewriter, 1732 NULL, fakewriter_tasks[i]); 1733 if (firsterr) 1734 goto unwind; 1735 } 1736 reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]), 1737 GFP_KERNEL); 1738 if (reader_tasks == NULL) { 1739 VERBOSE_TOROUT_ERRSTRING("out of memory"); 1740 firsterr = -ENOMEM; 1741 goto unwind; 1742 } 1743 for (i = 0; i < nrealreaders; i++) { 1744 firsterr = torture_create_kthread(rcu_torture_reader, NULL, 1745 reader_tasks[i]); 1746 if (firsterr) 1747 goto unwind; 1748 } 1749 if (stat_interval > 0) { 1750 firsterr = torture_create_kthread(rcu_torture_stats, NULL, 1751 stats_task); 1752 if (firsterr) 1753 goto unwind; 1754 } 1755 if (test_no_idle_hz) { 1756 firsterr = torture_shuffle_init(shuffle_interval * HZ); 1757 if (firsterr) 1758 goto unwind; 1759 } 1760 if (stutter < 0) 1761 stutter = 0; 1762 if (stutter) { 1763 firsterr = torture_stutter_init(stutter * HZ); 1764 if (firsterr) 1765 goto unwind; 1766 } 1767 if (fqs_duration < 0) 1768 fqs_duration = 0; 1769 if (fqs_duration) { 1770 /* Create the fqs thread */ 1771 firsterr = torture_create_kthread(rcu_torture_fqs, NULL, 1772 fqs_task); 1773 if (firsterr) 1774 goto unwind; 1775 } 1776 if (test_boost_interval < 1) 1777 test_boost_interval = 1; 1778 if (test_boost_duration < 2) 1779 test_boost_duration = 2; 1780 if ((test_boost == 1 && cur_ops->can_boost) || 1781 test_boost == 2) { 1782 1783 boost_starttime = jiffies + test_boost_interval * HZ; 1784 register_cpu_notifier(&rcutorture_cpu_nb); 1785 for_each_possible_cpu(i) { 1786 if (cpu_is_offline(i)) 1787 continue; /* Heuristic: CPU can go offline. */ 1788 firsterr = rcutorture_booster_init(i); 1789 if (firsterr) 1790 goto unwind; 1791 } 1792 } 1793 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup); 1794 if (firsterr) 1795 goto unwind; 1796 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval * HZ); 1797 if (firsterr) 1798 goto unwind; 1799 firsterr = rcu_torture_stall_init(); 1800 if (firsterr) 1801 goto unwind; 1802 firsterr = rcu_torture_barrier_init(); 1803 if (firsterr) 1804 goto unwind; 1805 if (object_debug) 1806 rcu_test_debug_objects(); 1807 if (cbflood_n_burst > 0) { 1808 /* Create the cbflood threads */ 1809 ncbflooders = (num_online_cpus() + 3) / 4; 1810 cbflood_task = kcalloc(ncbflooders, sizeof(*cbflood_task), 1811 GFP_KERNEL); 1812 if (!cbflood_task) { 1813 VERBOSE_TOROUT_ERRSTRING("out of memory"); 1814 firsterr = -ENOMEM; 1815 goto unwind; 1816 } 1817 for (i = 0; i < ncbflooders; i++) { 1818 firsterr = torture_create_kthread(rcu_torture_cbflood, 1819 NULL, 1820 cbflood_task[i]); 1821 if (firsterr) 1822 goto unwind; 1823 } 1824 } 1825 rcutorture_record_test_transition(); 1826 torture_init_end(); 1827 return 0; 1828 1829 unwind: 1830 torture_init_end(); 1831 rcu_torture_cleanup(); 1832 return firsterr; 1833 } 1834 1835 module_init(rcu_torture_init); 1836 module_exit(rcu_torture_cleanup); 1837