1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Read-Copy Update module-based torture test facility 4 * 5 * Copyright (C) IBM Corporation, 2005, 2006 6 * 7 * Authors: Paul E. McKenney <paulmck@linux.ibm.com> 8 * Josh Triplett <josh@joshtriplett.org> 9 * 10 * See also: Documentation/RCU/torture.rst 11 */ 12 13 #define pr_fmt(fmt) fmt 14 15 #include <linux/types.h> 16 #include <linux/kernel.h> 17 #include <linux/init.h> 18 #include <linux/module.h> 19 #include <linux/kthread.h> 20 #include <linux/err.h> 21 #include <linux/spinlock.h> 22 #include <linux/smp.h> 23 #include <linux/rcupdate_wait.h> 24 #include <linux/interrupt.h> 25 #include <linux/sched/signal.h> 26 #include <uapi/linux/sched/types.h> 27 #include <linux/atomic.h> 28 #include <linux/bitops.h> 29 #include <linux/completion.h> 30 #include <linux/moduleparam.h> 31 #include <linux/percpu.h> 32 #include <linux/notifier.h> 33 #include <linux/reboot.h> 34 #include <linux/freezer.h> 35 #include <linux/cpu.h> 36 #include <linux/delay.h> 37 #include <linux/stat.h> 38 #include <linux/srcu.h> 39 #include <linux/slab.h> 40 #include <linux/trace_clock.h> 41 #include <asm/byteorder.h> 42 #include <linux/torture.h> 43 #include <linux/vmalloc.h> 44 #include <linux/sched/debug.h> 45 #include <linux/sched/sysctl.h> 46 #include <linux/oom.h> 47 #include <linux/tick.h> 48 #include <linux/rcupdate_trace.h> 49 50 #include "rcu.h" 51 52 MODULE_LICENSE("GPL"); 53 MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com> and Josh Triplett <josh@joshtriplett.org>"); 54 55 #ifndef data_race 56 #define data_race(expr) \ 57 ({ \ 58 expr; \ 59 }) 60 #endif 61 #ifndef ASSERT_EXCLUSIVE_WRITER 62 #define ASSERT_EXCLUSIVE_WRITER(var) do { } while (0) 63 #endif 64 #ifndef ASSERT_EXCLUSIVE_ACCESS 65 #define ASSERT_EXCLUSIVE_ACCESS(var) do { } while (0) 66 #endif 67 68 /* Bits for ->extendables field, extendables param, and related definitions. */ 69 #define RCUTORTURE_RDR_SHIFT 8 /* Put SRCU index in upper bits. */ 70 #define RCUTORTURE_RDR_MASK ((1 << RCUTORTURE_RDR_SHIFT) - 1) 71 #define RCUTORTURE_RDR_BH 0x01 /* Extend readers by disabling bh. */ 72 #define RCUTORTURE_RDR_IRQ 0x02 /* ... disabling interrupts. */ 73 #define RCUTORTURE_RDR_PREEMPT 0x04 /* ... disabling preemption. */ 74 #define RCUTORTURE_RDR_RBH 0x08 /* ... rcu_read_lock_bh(). */ 75 #define RCUTORTURE_RDR_SCHED 0x10 /* ... rcu_read_lock_sched(). */ 76 #define RCUTORTURE_RDR_RCU 0x20 /* ... entering another RCU reader. */ 77 #define RCUTORTURE_RDR_NBITS 6 /* Number of bits defined above. */ 78 #define RCUTORTURE_MAX_EXTEND \ 79 (RCUTORTURE_RDR_BH | RCUTORTURE_RDR_IRQ | RCUTORTURE_RDR_PREEMPT | \ 80 RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED) 81 #define RCUTORTURE_RDR_MAX_LOOPS 0x7 /* Maximum reader extensions. */ 82 /* Must be power of two minus one. */ 83 #define RCUTORTURE_RDR_MAX_SEGS (RCUTORTURE_RDR_MAX_LOOPS + 3) 84 85 torture_param(int, extendables, RCUTORTURE_MAX_EXTEND, 86 "Extend readers by disabling bh (1), irqs (2), or preempt (4)"); 87 torture_param(int, fqs_duration, 0, 88 "Duration of fqs bursts (us), 0 to disable"); 89 torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)"); 90 torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)"); 91 torture_param(bool, fwd_progress, 1, "Test grace-period forward progress"); 92 torture_param(int, fwd_progress_div, 4, "Fraction of CPU stall to wait"); 93 torture_param(int, fwd_progress_holdoff, 60, 94 "Time between forward-progress tests (s)"); 95 torture_param(bool, fwd_progress_need_resched, 1, 96 "Hide cond_resched() behind need_resched()"); 97 torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives"); 98 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives"); 99 torture_param(bool, gp_normal, false, 100 "Use normal (non-expedited) GP wait primitives"); 101 torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives"); 102 torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers"); 103 torture_param(int, n_barrier_cbs, 0, 104 "# of callbacks/kthreads for barrier testing"); 105 torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads"); 106 torture_param(int, nreaders, -1, "Number of RCU reader threads"); 107 torture_param(int, object_debug, 0, 108 "Enable debug-object double call_rcu() testing"); 109 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)"); 110 torture_param(int, onoff_interval, 0, 111 "Time between CPU hotplugs (jiffies), 0=disable"); 112 torture_param(int, read_exit_delay, 13, 113 "Delay between read-then-exit episodes (s)"); 114 torture_param(int, read_exit_burst, 16, 115 "# of read-then-exit bursts per episode, zero to disable"); 116 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles"); 117 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable."); 118 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable."); 119 torture_param(int, stall_cpu_holdoff, 10, 120 "Time to wait before starting stall (s)."); 121 torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling."); 122 torture_param(int, stall_cpu_block, 0, "Sleep while stalling."); 123 torture_param(int, stall_gp_kthread, 0, 124 "Grace-period kthread stall duration (s)."); 125 torture_param(int, stat_interval, 60, 126 "Number of seconds between stats printk()s"); 127 torture_param(int, stutter, 5, "Number of seconds to run/halt test"); 128 torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes."); 129 torture_param(int, test_boost_duration, 4, 130 "Duration of each boost test, seconds."); 131 torture_param(int, test_boost_interval, 7, 132 "Interval between boost tests, seconds."); 133 torture_param(bool, test_no_idle_hz, true, 134 "Test support for tickless idle CPUs"); 135 torture_param(int, verbose, 1, 136 "Enable verbose debugging printk()s"); 137 138 static char *torture_type = "rcu"; 139 module_param(torture_type, charp, 0444); 140 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, srcu, ...)"); 141 142 static int nrealreaders; 143 static struct task_struct *writer_task; 144 static struct task_struct **fakewriter_tasks; 145 static struct task_struct **reader_tasks; 146 static struct task_struct *stats_task; 147 static struct task_struct *fqs_task; 148 static struct task_struct *boost_tasks[NR_CPUS]; 149 static struct task_struct *stall_task; 150 static struct task_struct *fwd_prog_task; 151 static struct task_struct **barrier_cbs_tasks; 152 static struct task_struct *barrier_task; 153 static struct task_struct *read_exit_task; 154 155 #define RCU_TORTURE_PIPE_LEN 10 156 157 struct rcu_torture { 158 struct rcu_head rtort_rcu; 159 int rtort_pipe_count; 160 struct list_head rtort_free; 161 int rtort_mbtest; 162 }; 163 164 static LIST_HEAD(rcu_torture_freelist); 165 static struct rcu_torture __rcu *rcu_torture_current; 166 static unsigned long rcu_torture_current_version; 167 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN]; 168 static DEFINE_SPINLOCK(rcu_torture_lock); 169 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count); 170 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch); 171 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1]; 172 static atomic_t n_rcu_torture_alloc; 173 static atomic_t n_rcu_torture_alloc_fail; 174 static atomic_t n_rcu_torture_free; 175 static atomic_t n_rcu_torture_mberror; 176 static atomic_t n_rcu_torture_error; 177 static long n_rcu_torture_barrier_error; 178 static long n_rcu_torture_boost_ktrerror; 179 static long n_rcu_torture_boost_rterror; 180 static long n_rcu_torture_boost_failure; 181 static long n_rcu_torture_boosts; 182 static atomic_long_t n_rcu_torture_timers; 183 static long n_barrier_attempts; 184 static long n_barrier_successes; /* did rcu_barrier test succeed? */ 185 static unsigned long n_read_exits; 186 static struct list_head rcu_torture_removed; 187 static unsigned long shutdown_jiffies; 188 189 static int rcu_torture_writer_state; 190 #define RTWS_FIXED_DELAY 0 191 #define RTWS_DELAY 1 192 #define RTWS_REPLACE 2 193 #define RTWS_DEF_FREE 3 194 #define RTWS_EXP_SYNC 4 195 #define RTWS_COND_GET 5 196 #define RTWS_COND_SYNC 6 197 #define RTWS_SYNC 7 198 #define RTWS_STUTTER 8 199 #define RTWS_STOPPING 9 200 static const char * const rcu_torture_writer_state_names[] = { 201 "RTWS_FIXED_DELAY", 202 "RTWS_DELAY", 203 "RTWS_REPLACE", 204 "RTWS_DEF_FREE", 205 "RTWS_EXP_SYNC", 206 "RTWS_COND_GET", 207 "RTWS_COND_SYNC", 208 "RTWS_SYNC", 209 "RTWS_STUTTER", 210 "RTWS_STOPPING", 211 }; 212 213 /* Record reader segment types and duration for first failing read. */ 214 struct rt_read_seg { 215 int rt_readstate; 216 unsigned long rt_delay_jiffies; 217 unsigned long rt_delay_ms; 218 unsigned long rt_delay_us; 219 bool rt_preempted; 220 }; 221 static int err_segs_recorded; 222 static struct rt_read_seg err_segs[RCUTORTURE_RDR_MAX_SEGS]; 223 static int rt_read_nsegs; 224 225 static const char *rcu_torture_writer_state_getname(void) 226 { 227 unsigned int i = READ_ONCE(rcu_torture_writer_state); 228 229 if (i >= ARRAY_SIZE(rcu_torture_writer_state_names)) 230 return "???"; 231 return rcu_torture_writer_state_names[i]; 232 } 233 234 #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) 235 #define rcu_can_boost() 1 236 #else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */ 237 #define rcu_can_boost() 0 238 #endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */ 239 240 #ifdef CONFIG_RCU_TRACE 241 static u64 notrace rcu_trace_clock_local(void) 242 { 243 u64 ts = trace_clock_local(); 244 245 (void)do_div(ts, NSEC_PER_USEC); 246 return ts; 247 } 248 #else /* #ifdef CONFIG_RCU_TRACE */ 249 static u64 notrace rcu_trace_clock_local(void) 250 { 251 return 0ULL; 252 } 253 #endif /* #else #ifdef CONFIG_RCU_TRACE */ 254 255 /* 256 * Stop aggressive CPU-hog tests a bit before the end of the test in order 257 * to avoid interfering with test shutdown. 258 */ 259 static bool shutdown_time_arrived(void) 260 { 261 return shutdown_secs && time_after(jiffies, shutdown_jiffies - 30 * HZ); 262 } 263 264 static unsigned long boost_starttime; /* jiffies of next boost test start. */ 265 static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */ 266 /* and boost task create/destroy. */ 267 static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */ 268 static bool barrier_phase; /* Test phase. */ 269 static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */ 270 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */ 271 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq); 272 273 static bool rcu_fwd_cb_nodelay; /* Short rcu_torture_delay() delays. */ 274 275 /* 276 * Allocate an element from the rcu_tortures pool. 277 */ 278 static struct rcu_torture * 279 rcu_torture_alloc(void) 280 { 281 struct list_head *p; 282 283 spin_lock_bh(&rcu_torture_lock); 284 if (list_empty(&rcu_torture_freelist)) { 285 atomic_inc(&n_rcu_torture_alloc_fail); 286 spin_unlock_bh(&rcu_torture_lock); 287 return NULL; 288 } 289 atomic_inc(&n_rcu_torture_alloc); 290 p = rcu_torture_freelist.next; 291 list_del_init(p); 292 spin_unlock_bh(&rcu_torture_lock); 293 return container_of(p, struct rcu_torture, rtort_free); 294 } 295 296 /* 297 * Free an element to the rcu_tortures pool. 298 */ 299 static void 300 rcu_torture_free(struct rcu_torture *p) 301 { 302 atomic_inc(&n_rcu_torture_free); 303 spin_lock_bh(&rcu_torture_lock); 304 list_add_tail(&p->rtort_free, &rcu_torture_freelist); 305 spin_unlock_bh(&rcu_torture_lock); 306 } 307 308 /* 309 * Operations vector for selecting different types of tests. 310 */ 311 312 struct rcu_torture_ops { 313 int ttype; 314 void (*init)(void); 315 void (*cleanup)(void); 316 int (*readlock)(void); 317 void (*read_delay)(struct torture_random_state *rrsp, 318 struct rt_read_seg *rtrsp); 319 void (*readunlock)(int idx); 320 unsigned long (*get_gp_seq)(void); 321 unsigned long (*gp_diff)(unsigned long new, unsigned long old); 322 void (*deferred_free)(struct rcu_torture *p); 323 void (*sync)(void); 324 void (*exp_sync)(void); 325 unsigned long (*get_state)(void); 326 void (*cond_sync)(unsigned long oldstate); 327 call_rcu_func_t call; 328 void (*cb_barrier)(void); 329 void (*fqs)(void); 330 void (*stats)(void); 331 int (*stall_dur)(void); 332 int irq_capable; 333 int can_boost; 334 int extendables; 335 int slow_gps; 336 const char *name; 337 }; 338 339 static struct rcu_torture_ops *cur_ops; 340 341 /* 342 * Definitions for rcu torture testing. 343 */ 344 345 static int rcu_torture_read_lock(void) __acquires(RCU) 346 { 347 rcu_read_lock(); 348 return 0; 349 } 350 351 static void 352 rcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp) 353 { 354 unsigned long started; 355 unsigned long completed; 356 const unsigned long shortdelay_us = 200; 357 unsigned long longdelay_ms = 300; 358 unsigned long long ts; 359 360 /* We want a short delay sometimes to make a reader delay the grace 361 * period, and we want a long delay occasionally to trigger 362 * force_quiescent_state. */ 363 364 if (!READ_ONCE(rcu_fwd_cb_nodelay) && 365 !(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) { 366 started = cur_ops->get_gp_seq(); 367 ts = rcu_trace_clock_local(); 368 if (preempt_count() & (SOFTIRQ_MASK | HARDIRQ_MASK)) 369 longdelay_ms = 5; /* Avoid triggering BH limits. */ 370 mdelay(longdelay_ms); 371 rtrsp->rt_delay_ms = longdelay_ms; 372 completed = cur_ops->get_gp_seq(); 373 do_trace_rcu_torture_read(cur_ops->name, NULL, ts, 374 started, completed); 375 } 376 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) { 377 udelay(shortdelay_us); 378 rtrsp->rt_delay_us = shortdelay_us; 379 } 380 if (!preempt_count() && 381 !(torture_random(rrsp) % (nrealreaders * 500))) { 382 torture_preempt_schedule(); /* QS only if preemptible. */ 383 rtrsp->rt_preempted = true; 384 } 385 } 386 387 static void rcu_torture_read_unlock(int idx) __releases(RCU) 388 { 389 rcu_read_unlock(); 390 } 391 392 /* 393 * Update callback in the pipe. This should be invoked after a grace period. 394 */ 395 static bool 396 rcu_torture_pipe_update_one(struct rcu_torture *rp) 397 { 398 int i; 399 400 i = READ_ONCE(rp->rtort_pipe_count); 401 if (i > RCU_TORTURE_PIPE_LEN) 402 i = RCU_TORTURE_PIPE_LEN; 403 atomic_inc(&rcu_torture_wcount[i]); 404 WRITE_ONCE(rp->rtort_pipe_count, i + 1); 405 if (rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) { 406 rp->rtort_mbtest = 0; 407 return true; 408 } 409 return false; 410 } 411 412 /* 413 * Update all callbacks in the pipe. Suitable for synchronous grace-period 414 * primitives. 415 */ 416 static void 417 rcu_torture_pipe_update(struct rcu_torture *old_rp) 418 { 419 struct rcu_torture *rp; 420 struct rcu_torture *rp1; 421 422 if (old_rp) 423 list_add(&old_rp->rtort_free, &rcu_torture_removed); 424 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) { 425 if (rcu_torture_pipe_update_one(rp)) { 426 list_del(&rp->rtort_free); 427 rcu_torture_free(rp); 428 } 429 } 430 } 431 432 static void 433 rcu_torture_cb(struct rcu_head *p) 434 { 435 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu); 436 437 if (torture_must_stop_irq()) { 438 /* Test is ending, just drop callbacks on the floor. */ 439 /* The next initialization will pick up the pieces. */ 440 return; 441 } 442 if (rcu_torture_pipe_update_one(rp)) 443 rcu_torture_free(rp); 444 else 445 cur_ops->deferred_free(rp); 446 } 447 448 static unsigned long rcu_no_completed(void) 449 { 450 return 0; 451 } 452 453 static void rcu_torture_deferred_free(struct rcu_torture *p) 454 { 455 call_rcu(&p->rtort_rcu, rcu_torture_cb); 456 } 457 458 static void rcu_sync_torture_init(void) 459 { 460 INIT_LIST_HEAD(&rcu_torture_removed); 461 } 462 463 static struct rcu_torture_ops rcu_ops = { 464 .ttype = RCU_FLAVOR, 465 .init = rcu_sync_torture_init, 466 .readlock = rcu_torture_read_lock, 467 .read_delay = rcu_read_delay, 468 .readunlock = rcu_torture_read_unlock, 469 .get_gp_seq = rcu_get_gp_seq, 470 .gp_diff = rcu_seq_diff, 471 .deferred_free = rcu_torture_deferred_free, 472 .sync = synchronize_rcu, 473 .exp_sync = synchronize_rcu_expedited, 474 .get_state = get_state_synchronize_rcu, 475 .cond_sync = cond_synchronize_rcu, 476 .call = call_rcu, 477 .cb_barrier = rcu_barrier, 478 .fqs = rcu_force_quiescent_state, 479 .stats = NULL, 480 .stall_dur = rcu_jiffies_till_stall_check, 481 .irq_capable = 1, 482 .can_boost = rcu_can_boost(), 483 .extendables = RCUTORTURE_MAX_EXTEND, 484 .name = "rcu" 485 }; 486 487 /* 488 * Don't even think about trying any of these in real life!!! 489 * The names includes "busted", and they really means it! 490 * The only purpose of these functions is to provide a buggy RCU 491 * implementation to make sure that rcutorture correctly emits 492 * buggy-RCU error messages. 493 */ 494 static void rcu_busted_torture_deferred_free(struct rcu_torture *p) 495 { 496 /* This is a deliberate bug for testing purposes only! */ 497 rcu_torture_cb(&p->rtort_rcu); 498 } 499 500 static void synchronize_rcu_busted(void) 501 { 502 /* This is a deliberate bug for testing purposes only! */ 503 } 504 505 static void 506 call_rcu_busted(struct rcu_head *head, rcu_callback_t func) 507 { 508 /* This is a deliberate bug for testing purposes only! */ 509 func(head); 510 } 511 512 static struct rcu_torture_ops rcu_busted_ops = { 513 .ttype = INVALID_RCU_FLAVOR, 514 .init = rcu_sync_torture_init, 515 .readlock = rcu_torture_read_lock, 516 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 517 .readunlock = rcu_torture_read_unlock, 518 .get_gp_seq = rcu_no_completed, 519 .deferred_free = rcu_busted_torture_deferred_free, 520 .sync = synchronize_rcu_busted, 521 .exp_sync = synchronize_rcu_busted, 522 .call = call_rcu_busted, 523 .cb_barrier = NULL, 524 .fqs = NULL, 525 .stats = NULL, 526 .irq_capable = 1, 527 .name = "busted" 528 }; 529 530 /* 531 * Definitions for srcu torture testing. 532 */ 533 534 DEFINE_STATIC_SRCU(srcu_ctl); 535 static struct srcu_struct srcu_ctld; 536 static struct srcu_struct *srcu_ctlp = &srcu_ctl; 537 538 static int srcu_torture_read_lock(void) __acquires(srcu_ctlp) 539 { 540 return srcu_read_lock(srcu_ctlp); 541 } 542 543 static void 544 srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp) 545 { 546 long delay; 547 const long uspertick = 1000000 / HZ; 548 const long longdelay = 10; 549 550 /* We want there to be long-running readers, but not all the time. */ 551 552 delay = torture_random(rrsp) % 553 (nrealreaders * 2 * longdelay * uspertick); 554 if (!delay && in_task()) { 555 schedule_timeout_interruptible(longdelay); 556 rtrsp->rt_delay_jiffies = longdelay; 557 } else { 558 rcu_read_delay(rrsp, rtrsp); 559 } 560 } 561 562 static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp) 563 { 564 srcu_read_unlock(srcu_ctlp, idx); 565 } 566 567 static unsigned long srcu_torture_completed(void) 568 { 569 return srcu_batches_completed(srcu_ctlp); 570 } 571 572 static void srcu_torture_deferred_free(struct rcu_torture *rp) 573 { 574 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb); 575 } 576 577 static void srcu_torture_synchronize(void) 578 { 579 synchronize_srcu(srcu_ctlp); 580 } 581 582 static void srcu_torture_call(struct rcu_head *head, 583 rcu_callback_t func) 584 { 585 call_srcu(srcu_ctlp, head, func); 586 } 587 588 static void srcu_torture_barrier(void) 589 { 590 srcu_barrier(srcu_ctlp); 591 } 592 593 static void srcu_torture_stats(void) 594 { 595 srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG); 596 } 597 598 static void srcu_torture_synchronize_expedited(void) 599 { 600 synchronize_srcu_expedited(srcu_ctlp); 601 } 602 603 static struct rcu_torture_ops srcu_ops = { 604 .ttype = SRCU_FLAVOR, 605 .init = rcu_sync_torture_init, 606 .readlock = srcu_torture_read_lock, 607 .read_delay = srcu_read_delay, 608 .readunlock = srcu_torture_read_unlock, 609 .get_gp_seq = srcu_torture_completed, 610 .deferred_free = srcu_torture_deferred_free, 611 .sync = srcu_torture_synchronize, 612 .exp_sync = srcu_torture_synchronize_expedited, 613 .call = srcu_torture_call, 614 .cb_barrier = srcu_torture_barrier, 615 .stats = srcu_torture_stats, 616 .irq_capable = 1, 617 .name = "srcu" 618 }; 619 620 static void srcu_torture_init(void) 621 { 622 rcu_sync_torture_init(); 623 WARN_ON(init_srcu_struct(&srcu_ctld)); 624 srcu_ctlp = &srcu_ctld; 625 } 626 627 static void srcu_torture_cleanup(void) 628 { 629 cleanup_srcu_struct(&srcu_ctld); 630 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */ 631 } 632 633 /* As above, but dynamically allocated. */ 634 static struct rcu_torture_ops srcud_ops = { 635 .ttype = SRCU_FLAVOR, 636 .init = srcu_torture_init, 637 .cleanup = srcu_torture_cleanup, 638 .readlock = srcu_torture_read_lock, 639 .read_delay = srcu_read_delay, 640 .readunlock = srcu_torture_read_unlock, 641 .get_gp_seq = srcu_torture_completed, 642 .deferred_free = srcu_torture_deferred_free, 643 .sync = srcu_torture_synchronize, 644 .exp_sync = srcu_torture_synchronize_expedited, 645 .call = srcu_torture_call, 646 .cb_barrier = srcu_torture_barrier, 647 .stats = srcu_torture_stats, 648 .irq_capable = 1, 649 .name = "srcud" 650 }; 651 652 /* As above, but broken due to inappropriate reader extension. */ 653 static struct rcu_torture_ops busted_srcud_ops = { 654 .ttype = SRCU_FLAVOR, 655 .init = srcu_torture_init, 656 .cleanup = srcu_torture_cleanup, 657 .readlock = srcu_torture_read_lock, 658 .read_delay = rcu_read_delay, 659 .readunlock = srcu_torture_read_unlock, 660 .get_gp_seq = srcu_torture_completed, 661 .deferred_free = srcu_torture_deferred_free, 662 .sync = srcu_torture_synchronize, 663 .exp_sync = srcu_torture_synchronize_expedited, 664 .call = srcu_torture_call, 665 .cb_barrier = srcu_torture_barrier, 666 .stats = srcu_torture_stats, 667 .irq_capable = 1, 668 .extendables = RCUTORTURE_MAX_EXTEND, 669 .name = "busted_srcud" 670 }; 671 672 /* 673 * Definitions for RCU-tasks torture testing. 674 */ 675 676 static int tasks_torture_read_lock(void) 677 { 678 return 0; 679 } 680 681 static void tasks_torture_read_unlock(int idx) 682 { 683 } 684 685 static void rcu_tasks_torture_deferred_free(struct rcu_torture *p) 686 { 687 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb); 688 } 689 690 static void synchronize_rcu_mult_test(void) 691 { 692 synchronize_rcu_mult(call_rcu_tasks, call_rcu); 693 } 694 695 static struct rcu_torture_ops tasks_ops = { 696 .ttype = RCU_TASKS_FLAVOR, 697 .init = rcu_sync_torture_init, 698 .readlock = tasks_torture_read_lock, 699 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 700 .readunlock = tasks_torture_read_unlock, 701 .get_gp_seq = rcu_no_completed, 702 .deferred_free = rcu_tasks_torture_deferred_free, 703 .sync = synchronize_rcu_tasks, 704 .exp_sync = synchronize_rcu_mult_test, 705 .call = call_rcu_tasks, 706 .cb_barrier = rcu_barrier_tasks, 707 .fqs = NULL, 708 .stats = NULL, 709 .irq_capable = 1, 710 .slow_gps = 1, 711 .name = "tasks" 712 }; 713 714 /* 715 * Definitions for trivial CONFIG_PREEMPT=n-only torture testing. 716 * This implementation does not necessarily work well with CPU hotplug. 717 */ 718 719 static void synchronize_rcu_trivial(void) 720 { 721 int cpu; 722 723 for_each_online_cpu(cpu) { 724 rcutorture_sched_setaffinity(current->pid, cpumask_of(cpu)); 725 WARN_ON_ONCE(raw_smp_processor_id() != cpu); 726 } 727 } 728 729 static int rcu_torture_read_lock_trivial(void) __acquires(RCU) 730 { 731 preempt_disable(); 732 return 0; 733 } 734 735 static void rcu_torture_read_unlock_trivial(int idx) __releases(RCU) 736 { 737 preempt_enable(); 738 } 739 740 static struct rcu_torture_ops trivial_ops = { 741 .ttype = RCU_TRIVIAL_FLAVOR, 742 .init = rcu_sync_torture_init, 743 .readlock = rcu_torture_read_lock_trivial, 744 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 745 .readunlock = rcu_torture_read_unlock_trivial, 746 .get_gp_seq = rcu_no_completed, 747 .sync = synchronize_rcu_trivial, 748 .exp_sync = synchronize_rcu_trivial, 749 .fqs = NULL, 750 .stats = NULL, 751 .irq_capable = 1, 752 .name = "trivial" 753 }; 754 755 /* 756 * Definitions for rude RCU-tasks torture testing. 757 */ 758 759 static void rcu_tasks_rude_torture_deferred_free(struct rcu_torture *p) 760 { 761 call_rcu_tasks_rude(&p->rtort_rcu, rcu_torture_cb); 762 } 763 764 static struct rcu_torture_ops tasks_rude_ops = { 765 .ttype = RCU_TASKS_RUDE_FLAVOR, 766 .init = rcu_sync_torture_init, 767 .readlock = rcu_torture_read_lock_trivial, 768 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 769 .readunlock = rcu_torture_read_unlock_trivial, 770 .get_gp_seq = rcu_no_completed, 771 .deferred_free = rcu_tasks_rude_torture_deferred_free, 772 .sync = synchronize_rcu_tasks_rude, 773 .exp_sync = synchronize_rcu_tasks_rude, 774 .call = call_rcu_tasks_rude, 775 .cb_barrier = rcu_barrier_tasks_rude, 776 .fqs = NULL, 777 .stats = NULL, 778 .irq_capable = 1, 779 .name = "tasks-rude" 780 }; 781 782 /* 783 * Definitions for tracing RCU-tasks torture testing. 784 */ 785 786 static int tasks_tracing_torture_read_lock(void) 787 { 788 rcu_read_lock_trace(); 789 return 0; 790 } 791 792 static void tasks_tracing_torture_read_unlock(int idx) 793 { 794 rcu_read_unlock_trace(); 795 } 796 797 static void rcu_tasks_tracing_torture_deferred_free(struct rcu_torture *p) 798 { 799 call_rcu_tasks_trace(&p->rtort_rcu, rcu_torture_cb); 800 } 801 802 static struct rcu_torture_ops tasks_tracing_ops = { 803 .ttype = RCU_TASKS_TRACING_FLAVOR, 804 .init = rcu_sync_torture_init, 805 .readlock = tasks_tracing_torture_read_lock, 806 .read_delay = srcu_read_delay, /* just reuse srcu's version. */ 807 .readunlock = tasks_tracing_torture_read_unlock, 808 .get_gp_seq = rcu_no_completed, 809 .deferred_free = rcu_tasks_tracing_torture_deferred_free, 810 .sync = synchronize_rcu_tasks_trace, 811 .exp_sync = synchronize_rcu_tasks_trace, 812 .call = call_rcu_tasks_trace, 813 .cb_barrier = rcu_barrier_tasks_trace, 814 .fqs = NULL, 815 .stats = NULL, 816 .irq_capable = 1, 817 .slow_gps = 1, 818 .name = "tasks-tracing" 819 }; 820 821 static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old) 822 { 823 if (!cur_ops->gp_diff) 824 return new - old; 825 return cur_ops->gp_diff(new, old); 826 } 827 828 static bool __maybe_unused torturing_tasks(void) 829 { 830 return cur_ops == &tasks_ops || cur_ops == &tasks_rude_ops; 831 } 832 833 /* 834 * RCU torture priority-boost testing. Runs one real-time thread per 835 * CPU for moderate bursts, repeatedly registering RCU callbacks and 836 * spinning waiting for them to be invoked. If a given callback takes 837 * too long to be invoked, we assume that priority inversion has occurred. 838 */ 839 840 struct rcu_boost_inflight { 841 struct rcu_head rcu; 842 int inflight; 843 }; 844 845 static void rcu_torture_boost_cb(struct rcu_head *head) 846 { 847 struct rcu_boost_inflight *rbip = 848 container_of(head, struct rcu_boost_inflight, rcu); 849 850 /* Ensure RCU-core accesses precede clearing ->inflight */ 851 smp_store_release(&rbip->inflight, 0); 852 } 853 854 static int old_rt_runtime = -1; 855 856 static void rcu_torture_disable_rt_throttle(void) 857 { 858 /* 859 * Disable RT throttling so that rcutorture's boost threads don't get 860 * throttled. Only possible if rcutorture is built-in otherwise the 861 * user should manually do this by setting the sched_rt_period_us and 862 * sched_rt_runtime sysctls. 863 */ 864 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime != -1) 865 return; 866 867 old_rt_runtime = sysctl_sched_rt_runtime; 868 sysctl_sched_rt_runtime = -1; 869 } 870 871 static void rcu_torture_enable_rt_throttle(void) 872 { 873 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime == -1) 874 return; 875 876 sysctl_sched_rt_runtime = old_rt_runtime; 877 old_rt_runtime = -1; 878 } 879 880 static bool rcu_torture_boost_failed(unsigned long start, unsigned long end) 881 { 882 if (end - start > test_boost_duration * HZ - HZ / 2) { 883 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed"); 884 n_rcu_torture_boost_failure++; 885 886 return true; /* failed */ 887 } 888 889 return false; /* passed */ 890 } 891 892 static int rcu_torture_boost(void *arg) 893 { 894 unsigned long call_rcu_time; 895 unsigned long endtime; 896 unsigned long oldstarttime; 897 struct rcu_boost_inflight rbi = { .inflight = 0 }; 898 899 VERBOSE_TOROUT_STRING("rcu_torture_boost started"); 900 901 /* Set real-time priority. */ 902 sched_set_fifo_low(current); 903 904 init_rcu_head_on_stack(&rbi.rcu); 905 /* Each pass through the following loop does one boost-test cycle. */ 906 do { 907 /* Track if the test failed already in this test interval? */ 908 bool failed = false; 909 910 /* Increment n_rcu_torture_boosts once per boost-test */ 911 while (!kthread_should_stop()) { 912 if (mutex_trylock(&boost_mutex)) { 913 n_rcu_torture_boosts++; 914 mutex_unlock(&boost_mutex); 915 break; 916 } 917 schedule_timeout_uninterruptible(1); 918 } 919 if (kthread_should_stop()) 920 goto checkwait; 921 922 /* Wait for the next test interval. */ 923 oldstarttime = boost_starttime; 924 while (time_before(jiffies, oldstarttime)) { 925 schedule_timeout_interruptible(oldstarttime - jiffies); 926 stutter_wait("rcu_torture_boost"); 927 if (torture_must_stop()) 928 goto checkwait; 929 } 930 931 /* Do one boost-test interval. */ 932 endtime = oldstarttime + test_boost_duration * HZ; 933 call_rcu_time = jiffies; 934 while (time_before(jiffies, endtime)) { 935 /* If we don't have a callback in flight, post one. */ 936 if (!smp_load_acquire(&rbi.inflight)) { 937 /* RCU core before ->inflight = 1. */ 938 smp_store_release(&rbi.inflight, 1); 939 call_rcu(&rbi.rcu, rcu_torture_boost_cb); 940 /* Check if the boost test failed */ 941 failed = failed || 942 rcu_torture_boost_failed(call_rcu_time, 943 jiffies); 944 call_rcu_time = jiffies; 945 } 946 stutter_wait("rcu_torture_boost"); 947 if (torture_must_stop()) 948 goto checkwait; 949 } 950 951 /* 952 * If boost never happened, then inflight will always be 1, in 953 * this case the boost check would never happen in the above 954 * loop so do another one here. 955 */ 956 if (!failed && smp_load_acquire(&rbi.inflight)) 957 rcu_torture_boost_failed(call_rcu_time, jiffies); 958 959 /* 960 * Set the start time of the next test interval. 961 * Yes, this is vulnerable to long delays, but such 962 * delays simply cause a false negative for the next 963 * interval. Besides, we are running at RT priority, 964 * so delays should be relatively rare. 965 */ 966 while (oldstarttime == boost_starttime && 967 !kthread_should_stop()) { 968 if (mutex_trylock(&boost_mutex)) { 969 boost_starttime = jiffies + 970 test_boost_interval * HZ; 971 mutex_unlock(&boost_mutex); 972 break; 973 } 974 schedule_timeout_uninterruptible(1); 975 } 976 977 /* Go do the stutter. */ 978 checkwait: stutter_wait("rcu_torture_boost"); 979 } while (!torture_must_stop()); 980 981 /* Clean up and exit. */ 982 while (!kthread_should_stop() || smp_load_acquire(&rbi.inflight)) { 983 torture_shutdown_absorb("rcu_torture_boost"); 984 schedule_timeout_uninterruptible(1); 985 } 986 destroy_rcu_head_on_stack(&rbi.rcu); 987 torture_kthread_stopping("rcu_torture_boost"); 988 return 0; 989 } 990 991 /* 992 * RCU torture force-quiescent-state kthread. Repeatedly induces 993 * bursts of calls to force_quiescent_state(), increasing the probability 994 * of occurrence of some important types of race conditions. 995 */ 996 static int 997 rcu_torture_fqs(void *arg) 998 { 999 unsigned long fqs_resume_time; 1000 int fqs_burst_remaining; 1001 1002 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started"); 1003 do { 1004 fqs_resume_time = jiffies + fqs_stutter * HZ; 1005 while (time_before(jiffies, fqs_resume_time) && 1006 !kthread_should_stop()) { 1007 schedule_timeout_interruptible(1); 1008 } 1009 fqs_burst_remaining = fqs_duration; 1010 while (fqs_burst_remaining > 0 && 1011 !kthread_should_stop()) { 1012 cur_ops->fqs(); 1013 udelay(fqs_holdoff); 1014 fqs_burst_remaining -= fqs_holdoff; 1015 } 1016 stutter_wait("rcu_torture_fqs"); 1017 } while (!torture_must_stop()); 1018 torture_kthread_stopping("rcu_torture_fqs"); 1019 return 0; 1020 } 1021 1022 /* 1023 * RCU torture writer kthread. Repeatedly substitutes a new structure 1024 * for that pointed to by rcu_torture_current, freeing the old structure 1025 * after a series of grace periods (the "pipeline"). 1026 */ 1027 static int 1028 rcu_torture_writer(void *arg) 1029 { 1030 bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal(); 1031 int expediting = 0; 1032 unsigned long gp_snap; 1033 bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal; 1034 bool gp_sync1 = gp_sync; 1035 int i; 1036 struct rcu_torture *rp; 1037 struct rcu_torture *old_rp; 1038 static DEFINE_TORTURE_RANDOM(rand); 1039 int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC, 1040 RTWS_COND_GET, RTWS_SYNC }; 1041 int nsynctypes = 0; 1042 1043 VERBOSE_TOROUT_STRING("rcu_torture_writer task started"); 1044 if (!can_expedite) 1045 pr_alert("%s" TORTURE_FLAG 1046 " GP expediting controlled from boot/sysfs for %s.\n", 1047 torture_type, cur_ops->name); 1048 1049 /* Initialize synctype[] array. If none set, take default. */ 1050 if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync1) 1051 gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true; 1052 if (gp_cond1 && cur_ops->get_state && cur_ops->cond_sync) { 1053 synctype[nsynctypes++] = RTWS_COND_GET; 1054 pr_info("%s: Testing conditional GPs.\n", __func__); 1055 } else if (gp_cond && (!cur_ops->get_state || !cur_ops->cond_sync)) { 1056 pr_alert("%s: gp_cond without primitives.\n", __func__); 1057 } 1058 if (gp_exp1 && cur_ops->exp_sync) { 1059 synctype[nsynctypes++] = RTWS_EXP_SYNC; 1060 pr_info("%s: Testing expedited GPs.\n", __func__); 1061 } else if (gp_exp && !cur_ops->exp_sync) { 1062 pr_alert("%s: gp_exp without primitives.\n", __func__); 1063 } 1064 if (gp_normal1 && cur_ops->deferred_free) { 1065 synctype[nsynctypes++] = RTWS_DEF_FREE; 1066 pr_info("%s: Testing asynchronous GPs.\n", __func__); 1067 } else if (gp_normal && !cur_ops->deferred_free) { 1068 pr_alert("%s: gp_normal without primitives.\n", __func__); 1069 } 1070 if (gp_sync1 && cur_ops->sync) { 1071 synctype[nsynctypes++] = RTWS_SYNC; 1072 pr_info("%s: Testing normal GPs.\n", __func__); 1073 } else if (gp_sync && !cur_ops->sync) { 1074 pr_alert("%s: gp_sync without primitives.\n", __func__); 1075 } 1076 if (WARN_ONCE(nsynctypes == 0, 1077 "rcu_torture_writer: No update-side primitives.\n")) { 1078 /* 1079 * No updates primitives, so don't try updating. 1080 * The resulting test won't be testing much, hence the 1081 * above WARN_ONCE(). 1082 */ 1083 rcu_torture_writer_state = RTWS_STOPPING; 1084 torture_kthread_stopping("rcu_torture_writer"); 1085 } 1086 1087 do { 1088 rcu_torture_writer_state = RTWS_FIXED_DELAY; 1089 schedule_timeout_uninterruptible(1); 1090 rp = rcu_torture_alloc(); 1091 if (rp == NULL) 1092 continue; 1093 rp->rtort_pipe_count = 0; 1094 rcu_torture_writer_state = RTWS_DELAY; 1095 udelay(torture_random(&rand) & 0x3ff); 1096 rcu_torture_writer_state = RTWS_REPLACE; 1097 old_rp = rcu_dereference_check(rcu_torture_current, 1098 current == writer_task); 1099 rp->rtort_mbtest = 1; 1100 rcu_assign_pointer(rcu_torture_current, rp); 1101 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */ 1102 if (old_rp) { 1103 i = old_rp->rtort_pipe_count; 1104 if (i > RCU_TORTURE_PIPE_LEN) 1105 i = RCU_TORTURE_PIPE_LEN; 1106 atomic_inc(&rcu_torture_wcount[i]); 1107 WRITE_ONCE(old_rp->rtort_pipe_count, 1108 old_rp->rtort_pipe_count + 1); 1109 switch (synctype[torture_random(&rand) % nsynctypes]) { 1110 case RTWS_DEF_FREE: 1111 rcu_torture_writer_state = RTWS_DEF_FREE; 1112 cur_ops->deferred_free(old_rp); 1113 break; 1114 case RTWS_EXP_SYNC: 1115 rcu_torture_writer_state = RTWS_EXP_SYNC; 1116 cur_ops->exp_sync(); 1117 rcu_torture_pipe_update(old_rp); 1118 break; 1119 case RTWS_COND_GET: 1120 rcu_torture_writer_state = RTWS_COND_GET; 1121 gp_snap = cur_ops->get_state(); 1122 i = torture_random(&rand) % 16; 1123 if (i != 0) 1124 schedule_timeout_interruptible(i); 1125 udelay(torture_random(&rand) % 1000); 1126 rcu_torture_writer_state = RTWS_COND_SYNC; 1127 cur_ops->cond_sync(gp_snap); 1128 rcu_torture_pipe_update(old_rp); 1129 break; 1130 case RTWS_SYNC: 1131 rcu_torture_writer_state = RTWS_SYNC; 1132 cur_ops->sync(); 1133 rcu_torture_pipe_update(old_rp); 1134 break; 1135 default: 1136 WARN_ON_ONCE(1); 1137 break; 1138 } 1139 } 1140 WRITE_ONCE(rcu_torture_current_version, 1141 rcu_torture_current_version + 1); 1142 /* Cycle through nesting levels of rcu_expedite_gp() calls. */ 1143 if (can_expedite && 1144 !(torture_random(&rand) & 0xff & (!!expediting - 1))) { 1145 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited()); 1146 if (expediting >= 0) 1147 rcu_expedite_gp(); 1148 else 1149 rcu_unexpedite_gp(); 1150 if (++expediting > 3) 1151 expediting = -expediting; 1152 } else if (!can_expedite) { /* Disabled during boot, recheck. */ 1153 can_expedite = !rcu_gp_is_expedited() && 1154 !rcu_gp_is_normal(); 1155 } 1156 rcu_torture_writer_state = RTWS_STUTTER; 1157 if (stutter_wait("rcu_torture_writer") && 1158 !READ_ONCE(rcu_fwd_cb_nodelay) && 1159 !cur_ops->slow_gps && 1160 !torture_must_stop() && 1161 rcu_inkernel_boot_has_ended()) 1162 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) 1163 if (list_empty(&rcu_tortures[i].rtort_free) && 1164 rcu_access_pointer(rcu_torture_current) != 1165 &rcu_tortures[i]) { 1166 rcu_ftrace_dump(DUMP_ALL); 1167 WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count); 1168 } 1169 } while (!torture_must_stop()); 1170 rcu_torture_current = NULL; // Let stats task know that we are done. 1171 /* Reset expediting back to unexpedited. */ 1172 if (expediting > 0) 1173 expediting = -expediting; 1174 while (can_expedite && expediting++ < 0) 1175 rcu_unexpedite_gp(); 1176 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited()); 1177 if (!can_expedite) 1178 pr_alert("%s" TORTURE_FLAG 1179 " Dynamic grace-period expediting was disabled.\n", 1180 torture_type); 1181 rcu_torture_writer_state = RTWS_STOPPING; 1182 torture_kthread_stopping("rcu_torture_writer"); 1183 return 0; 1184 } 1185 1186 /* 1187 * RCU torture fake writer kthread. Repeatedly calls sync, with a random 1188 * delay between calls. 1189 */ 1190 static int 1191 rcu_torture_fakewriter(void *arg) 1192 { 1193 DEFINE_TORTURE_RANDOM(rand); 1194 1195 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started"); 1196 set_user_nice(current, MAX_NICE); 1197 1198 do { 1199 schedule_timeout_uninterruptible(1 + torture_random(&rand)%10); 1200 udelay(torture_random(&rand) & 0x3ff); 1201 if (cur_ops->cb_barrier != NULL && 1202 torture_random(&rand) % (nfakewriters * 8) == 0) { 1203 cur_ops->cb_barrier(); 1204 } else if (gp_normal == gp_exp) { 1205 if (cur_ops->sync && torture_random(&rand) & 0x80) 1206 cur_ops->sync(); 1207 else if (cur_ops->exp_sync) 1208 cur_ops->exp_sync(); 1209 } else if (gp_normal && cur_ops->sync) { 1210 cur_ops->sync(); 1211 } else if (cur_ops->exp_sync) { 1212 cur_ops->exp_sync(); 1213 } 1214 stutter_wait("rcu_torture_fakewriter"); 1215 } while (!torture_must_stop()); 1216 1217 torture_kthread_stopping("rcu_torture_fakewriter"); 1218 return 0; 1219 } 1220 1221 static void rcu_torture_timer_cb(struct rcu_head *rhp) 1222 { 1223 kfree(rhp); 1224 } 1225 1226 /* 1227 * Do one extension of an RCU read-side critical section using the 1228 * current reader state in readstate (set to zero for initial entry 1229 * to extended critical section), set the new state as specified by 1230 * newstate (set to zero for final exit from extended critical section), 1231 * and random-number-generator state in trsp. If this is neither the 1232 * beginning or end of the critical section and if there was actually a 1233 * change, do a ->read_delay(). 1234 */ 1235 static void rcutorture_one_extend(int *readstate, int newstate, 1236 struct torture_random_state *trsp, 1237 struct rt_read_seg *rtrsp) 1238 { 1239 unsigned long flags; 1240 int idxnew = -1; 1241 int idxold = *readstate; 1242 int statesnew = ~*readstate & newstate; 1243 int statesold = *readstate & ~newstate; 1244 1245 WARN_ON_ONCE(idxold < 0); 1246 WARN_ON_ONCE((idxold >> RCUTORTURE_RDR_SHIFT) > 1); 1247 rtrsp->rt_readstate = newstate; 1248 1249 /* First, put new protection in place to avoid critical-section gap. */ 1250 if (statesnew & RCUTORTURE_RDR_BH) 1251 local_bh_disable(); 1252 if (statesnew & RCUTORTURE_RDR_IRQ) 1253 local_irq_disable(); 1254 if (statesnew & RCUTORTURE_RDR_PREEMPT) 1255 preempt_disable(); 1256 if (statesnew & RCUTORTURE_RDR_RBH) 1257 rcu_read_lock_bh(); 1258 if (statesnew & RCUTORTURE_RDR_SCHED) 1259 rcu_read_lock_sched(); 1260 if (statesnew & RCUTORTURE_RDR_RCU) 1261 idxnew = cur_ops->readlock() << RCUTORTURE_RDR_SHIFT; 1262 1263 /* Next, remove old protection, irq first due to bh conflict. */ 1264 if (statesold & RCUTORTURE_RDR_IRQ) 1265 local_irq_enable(); 1266 if (statesold & RCUTORTURE_RDR_BH) 1267 local_bh_enable(); 1268 if (statesold & RCUTORTURE_RDR_PREEMPT) 1269 preempt_enable(); 1270 if (statesold & RCUTORTURE_RDR_RBH) 1271 rcu_read_unlock_bh(); 1272 if (statesold & RCUTORTURE_RDR_SCHED) 1273 rcu_read_unlock_sched(); 1274 if (statesold & RCUTORTURE_RDR_RCU) { 1275 bool lockit = !statesnew && !(torture_random(trsp) & 0xffff); 1276 1277 if (lockit) 1278 raw_spin_lock_irqsave(¤t->pi_lock, flags); 1279 cur_ops->readunlock(idxold >> RCUTORTURE_RDR_SHIFT); 1280 if (lockit) 1281 raw_spin_unlock_irqrestore(¤t->pi_lock, flags); 1282 } 1283 1284 /* Delay if neither beginning nor end and there was a change. */ 1285 if ((statesnew || statesold) && *readstate && newstate) 1286 cur_ops->read_delay(trsp, rtrsp); 1287 1288 /* Update the reader state. */ 1289 if (idxnew == -1) 1290 idxnew = idxold & ~RCUTORTURE_RDR_MASK; 1291 WARN_ON_ONCE(idxnew < 0); 1292 WARN_ON_ONCE((idxnew >> RCUTORTURE_RDR_SHIFT) > 1); 1293 *readstate = idxnew | newstate; 1294 WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT) < 0); 1295 WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT) > 1); 1296 } 1297 1298 /* Return the biggest extendables mask given current RCU and boot parameters. */ 1299 static int rcutorture_extend_mask_max(void) 1300 { 1301 int mask; 1302 1303 WARN_ON_ONCE(extendables & ~RCUTORTURE_MAX_EXTEND); 1304 mask = extendables & RCUTORTURE_MAX_EXTEND & cur_ops->extendables; 1305 mask = mask | RCUTORTURE_RDR_RCU; 1306 return mask; 1307 } 1308 1309 /* Return a random protection state mask, but with at least one bit set. */ 1310 static int 1311 rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp) 1312 { 1313 int mask = rcutorture_extend_mask_max(); 1314 unsigned long randmask1 = torture_random(trsp) >> 8; 1315 unsigned long randmask2 = randmask1 >> 3; 1316 1317 WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT); 1318 /* Mostly only one bit (need preemption!), sometimes lots of bits. */ 1319 if (!(randmask1 & 0x7)) 1320 mask = mask & randmask2; 1321 else 1322 mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS)); 1323 /* Can't enable bh w/irq disabled. */ 1324 if ((mask & RCUTORTURE_RDR_IRQ) && 1325 ((!(mask & RCUTORTURE_RDR_BH) && (oldmask & RCUTORTURE_RDR_BH)) || 1326 (!(mask & RCUTORTURE_RDR_RBH) && (oldmask & RCUTORTURE_RDR_RBH)))) 1327 mask |= RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH; 1328 return mask ?: RCUTORTURE_RDR_RCU; 1329 } 1330 1331 /* 1332 * Do a randomly selected number of extensions of an existing RCU read-side 1333 * critical section. 1334 */ 1335 static struct rt_read_seg * 1336 rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp, 1337 struct rt_read_seg *rtrsp) 1338 { 1339 int i; 1340 int j; 1341 int mask = rcutorture_extend_mask_max(); 1342 1343 WARN_ON_ONCE(!*readstate); /* -Existing- RCU read-side critsect! */ 1344 if (!((mask - 1) & mask)) 1345 return rtrsp; /* Current RCU reader not extendable. */ 1346 /* Bias towards larger numbers of loops. */ 1347 i = (torture_random(trsp) >> 3); 1348 i = ((i | (i >> 3)) & RCUTORTURE_RDR_MAX_LOOPS) + 1; 1349 for (j = 0; j < i; j++) { 1350 mask = rcutorture_extend_mask(*readstate, trsp); 1351 rcutorture_one_extend(readstate, mask, trsp, &rtrsp[j]); 1352 } 1353 return &rtrsp[j]; 1354 } 1355 1356 /* 1357 * Do one read-side critical section, returning false if there was 1358 * no data to read. Can be invoked both from process context and 1359 * from a timer handler. 1360 */ 1361 static bool rcu_torture_one_read(struct torture_random_state *trsp) 1362 { 1363 int i; 1364 unsigned long started; 1365 unsigned long completed; 1366 int newstate; 1367 struct rcu_torture *p; 1368 int pipe_count; 1369 int readstate = 0; 1370 struct rt_read_seg rtseg[RCUTORTURE_RDR_MAX_SEGS] = { { 0 } }; 1371 struct rt_read_seg *rtrsp = &rtseg[0]; 1372 struct rt_read_seg *rtrsp1; 1373 unsigned long long ts; 1374 1375 WARN_ON_ONCE(!rcu_is_watching()); 1376 newstate = rcutorture_extend_mask(readstate, trsp); 1377 rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++); 1378 started = cur_ops->get_gp_seq(); 1379 ts = rcu_trace_clock_local(); 1380 p = rcu_dereference_check(rcu_torture_current, 1381 rcu_read_lock_bh_held() || 1382 rcu_read_lock_sched_held() || 1383 srcu_read_lock_held(srcu_ctlp) || 1384 rcu_read_lock_trace_held() || 1385 torturing_tasks()); 1386 if (p == NULL) { 1387 /* Wait for rcu_torture_writer to get underway */ 1388 rcutorture_one_extend(&readstate, 0, trsp, rtrsp); 1389 return false; 1390 } 1391 if (p->rtort_mbtest == 0) 1392 atomic_inc(&n_rcu_torture_mberror); 1393 rtrsp = rcutorture_loop_extend(&readstate, trsp, rtrsp); 1394 preempt_disable(); 1395 pipe_count = READ_ONCE(p->rtort_pipe_count); 1396 if (pipe_count > RCU_TORTURE_PIPE_LEN) { 1397 /* Should not happen, but... */ 1398 pipe_count = RCU_TORTURE_PIPE_LEN; 1399 } 1400 completed = cur_ops->get_gp_seq(); 1401 if (pipe_count > 1) { 1402 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, 1403 ts, started, completed); 1404 rcu_ftrace_dump(DUMP_ALL); 1405 } 1406 __this_cpu_inc(rcu_torture_count[pipe_count]); 1407 completed = rcutorture_seq_diff(completed, started); 1408 if (completed > RCU_TORTURE_PIPE_LEN) { 1409 /* Should not happen, but... */ 1410 completed = RCU_TORTURE_PIPE_LEN; 1411 } 1412 __this_cpu_inc(rcu_torture_batch[completed]); 1413 preempt_enable(); 1414 rcutorture_one_extend(&readstate, 0, trsp, rtrsp); 1415 WARN_ON_ONCE(readstate & RCUTORTURE_RDR_MASK); 1416 1417 /* If error or close call, record the sequence of reader protections. */ 1418 if ((pipe_count > 1 || completed > 1) && !xchg(&err_segs_recorded, 1)) { 1419 i = 0; 1420 for (rtrsp1 = &rtseg[0]; rtrsp1 < rtrsp; rtrsp1++) 1421 err_segs[i++] = *rtrsp1; 1422 rt_read_nsegs = i; 1423 } 1424 1425 return true; 1426 } 1427 1428 static DEFINE_TORTURE_RANDOM_PERCPU(rcu_torture_timer_rand); 1429 1430 /* 1431 * RCU torture reader from timer handler. Dereferences rcu_torture_current, 1432 * incrementing the corresponding element of the pipeline array. The 1433 * counter in the element should never be greater than 1, otherwise, the 1434 * RCU implementation is broken. 1435 */ 1436 static void rcu_torture_timer(struct timer_list *unused) 1437 { 1438 atomic_long_inc(&n_rcu_torture_timers); 1439 (void)rcu_torture_one_read(this_cpu_ptr(&rcu_torture_timer_rand)); 1440 1441 /* Test call_rcu() invocation from interrupt handler. */ 1442 if (cur_ops->call) { 1443 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT); 1444 1445 if (rhp) 1446 cur_ops->call(rhp, rcu_torture_timer_cb); 1447 } 1448 } 1449 1450 /* 1451 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current, 1452 * incrementing the corresponding element of the pipeline array. The 1453 * counter in the element should never be greater than 1, otherwise, the 1454 * RCU implementation is broken. 1455 */ 1456 static int 1457 rcu_torture_reader(void *arg) 1458 { 1459 unsigned long lastsleep = jiffies; 1460 long myid = (long)arg; 1461 int mynumonline = myid; 1462 DEFINE_TORTURE_RANDOM(rand); 1463 struct timer_list t; 1464 1465 VERBOSE_TOROUT_STRING("rcu_torture_reader task started"); 1466 set_user_nice(current, MAX_NICE); 1467 if (irqreader && cur_ops->irq_capable) 1468 timer_setup_on_stack(&t, rcu_torture_timer, 0); 1469 tick_dep_set_task(current, TICK_DEP_BIT_RCU); 1470 do { 1471 if (irqreader && cur_ops->irq_capable) { 1472 if (!timer_pending(&t)) 1473 mod_timer(&t, jiffies + 1); 1474 } 1475 if (!rcu_torture_one_read(&rand) && !torture_must_stop()) 1476 schedule_timeout_interruptible(HZ); 1477 if (time_after(jiffies, lastsleep) && !torture_must_stop()) { 1478 schedule_timeout_interruptible(1); 1479 lastsleep = jiffies + 10; 1480 } 1481 while (num_online_cpus() < mynumonline && !torture_must_stop()) 1482 schedule_timeout_interruptible(HZ / 5); 1483 stutter_wait("rcu_torture_reader"); 1484 } while (!torture_must_stop()); 1485 if (irqreader && cur_ops->irq_capable) { 1486 del_timer_sync(&t); 1487 destroy_timer_on_stack(&t); 1488 } 1489 tick_dep_clear_task(current, TICK_DEP_BIT_RCU); 1490 torture_kthread_stopping("rcu_torture_reader"); 1491 return 0; 1492 } 1493 1494 /* 1495 * Print torture statistics. Caller must ensure that there is only 1496 * one call to this function at a given time!!! This is normally 1497 * accomplished by relying on the module system to only have one copy 1498 * of the module loaded, and then by giving the rcu_torture_stats 1499 * kthread full control (or the init/cleanup functions when rcu_torture_stats 1500 * thread is not running). 1501 */ 1502 static void 1503 rcu_torture_stats_print(void) 1504 { 1505 int cpu; 1506 int i; 1507 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; 1508 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; 1509 struct rcu_torture *rtcp; 1510 static unsigned long rtcv_snap = ULONG_MAX; 1511 static bool splatted; 1512 struct task_struct *wtp; 1513 1514 for_each_possible_cpu(cpu) { 1515 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 1516 pipesummary[i] += READ_ONCE(per_cpu(rcu_torture_count, cpu)[i]); 1517 batchsummary[i] += READ_ONCE(per_cpu(rcu_torture_batch, cpu)[i]); 1518 } 1519 } 1520 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) { 1521 if (pipesummary[i] != 0) 1522 break; 1523 } 1524 1525 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1526 rtcp = rcu_access_pointer(rcu_torture_current); 1527 pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ", 1528 rtcp, 1529 rtcp && !rcu_stall_is_suppressed_at_boot() ? "ver" : "VER", 1530 rcu_torture_current_version, 1531 list_empty(&rcu_torture_freelist), 1532 atomic_read(&n_rcu_torture_alloc), 1533 atomic_read(&n_rcu_torture_alloc_fail), 1534 atomic_read(&n_rcu_torture_free)); 1535 pr_cont("rtmbe: %d rtbe: %ld rtbke: %ld rtbre: %ld ", 1536 atomic_read(&n_rcu_torture_mberror), 1537 n_rcu_torture_barrier_error, 1538 n_rcu_torture_boost_ktrerror, 1539 n_rcu_torture_boost_rterror); 1540 pr_cont("rtbf: %ld rtb: %ld nt: %ld ", 1541 n_rcu_torture_boost_failure, 1542 n_rcu_torture_boosts, 1543 atomic_long_read(&n_rcu_torture_timers)); 1544 torture_onoff_stats(); 1545 pr_cont("barrier: %ld/%ld:%ld ", 1546 data_race(n_barrier_successes), 1547 data_race(n_barrier_attempts), 1548 data_race(n_rcu_torture_barrier_error)); 1549 pr_cont("read-exits: %ld\n", data_race(n_read_exits)); 1550 1551 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1552 if (atomic_read(&n_rcu_torture_mberror) || 1553 n_rcu_torture_barrier_error || n_rcu_torture_boost_ktrerror || 1554 n_rcu_torture_boost_rterror || n_rcu_torture_boost_failure || 1555 i > 1) { 1556 pr_cont("%s", "!!! "); 1557 atomic_inc(&n_rcu_torture_error); 1558 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mberror)); 1559 WARN_ON_ONCE(n_rcu_torture_barrier_error); // rcu_barrier() 1560 WARN_ON_ONCE(n_rcu_torture_boost_ktrerror); // no boost kthread 1561 WARN_ON_ONCE(n_rcu_torture_boost_rterror); // can't set RT prio 1562 WARN_ON_ONCE(n_rcu_torture_boost_failure); // RCU boost failed 1563 WARN_ON_ONCE(i > 1); // Too-short grace period 1564 } 1565 pr_cont("Reader Pipe: "); 1566 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 1567 pr_cont(" %ld", pipesummary[i]); 1568 pr_cont("\n"); 1569 1570 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1571 pr_cont("Reader Batch: "); 1572 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 1573 pr_cont(" %ld", batchsummary[i]); 1574 pr_cont("\n"); 1575 1576 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1577 pr_cont("Free-Block Circulation: "); 1578 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 1579 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i])); 1580 } 1581 pr_cont("\n"); 1582 1583 if (cur_ops->stats) 1584 cur_ops->stats(); 1585 if (rtcv_snap == rcu_torture_current_version && 1586 rcu_access_pointer(rcu_torture_current) && 1587 !rcu_stall_is_suppressed()) { 1588 int __maybe_unused flags = 0; 1589 unsigned long __maybe_unused gp_seq = 0; 1590 1591 rcutorture_get_gp_data(cur_ops->ttype, 1592 &flags, &gp_seq); 1593 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, 1594 &flags, &gp_seq); 1595 wtp = READ_ONCE(writer_task); 1596 pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#lx cpu %d\n", 1597 rcu_torture_writer_state_getname(), 1598 rcu_torture_writer_state, gp_seq, flags, 1599 wtp == NULL ? ~0UL : wtp->state, 1600 wtp == NULL ? -1 : (int)task_cpu(wtp)); 1601 if (!splatted && wtp) { 1602 sched_show_task(wtp); 1603 splatted = true; 1604 } 1605 show_rcu_gp_kthreads(); 1606 rcu_ftrace_dump(DUMP_ALL); 1607 } 1608 rtcv_snap = rcu_torture_current_version; 1609 } 1610 1611 /* 1612 * Periodically prints torture statistics, if periodic statistics printing 1613 * was specified via the stat_interval module parameter. 1614 */ 1615 static int 1616 rcu_torture_stats(void *arg) 1617 { 1618 VERBOSE_TOROUT_STRING("rcu_torture_stats task started"); 1619 do { 1620 schedule_timeout_interruptible(stat_interval * HZ); 1621 rcu_torture_stats_print(); 1622 torture_shutdown_absorb("rcu_torture_stats"); 1623 } while (!torture_must_stop()); 1624 torture_kthread_stopping("rcu_torture_stats"); 1625 return 0; 1626 } 1627 1628 static void 1629 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag) 1630 { 1631 pr_alert("%s" TORTURE_FLAG 1632 "--- %s: nreaders=%d nfakewriters=%d " 1633 "stat_interval=%d verbose=%d test_no_idle_hz=%d " 1634 "shuffle_interval=%d stutter=%d irqreader=%d " 1635 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d " 1636 "test_boost=%d/%d test_boost_interval=%d " 1637 "test_boost_duration=%d shutdown_secs=%d " 1638 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d " 1639 "stall_cpu_block=%d " 1640 "n_barrier_cbs=%d " 1641 "onoff_interval=%d onoff_holdoff=%d " 1642 "read_exit_delay=%d read_exit_burst=%d\n", 1643 torture_type, tag, nrealreaders, nfakewriters, 1644 stat_interval, verbose, test_no_idle_hz, shuffle_interval, 1645 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter, 1646 test_boost, cur_ops->can_boost, 1647 test_boost_interval, test_boost_duration, shutdown_secs, 1648 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff, 1649 stall_cpu_block, 1650 n_barrier_cbs, 1651 onoff_interval, onoff_holdoff, 1652 read_exit_delay, read_exit_burst); 1653 } 1654 1655 static int rcutorture_booster_cleanup(unsigned int cpu) 1656 { 1657 struct task_struct *t; 1658 1659 if (boost_tasks[cpu] == NULL) 1660 return 0; 1661 mutex_lock(&boost_mutex); 1662 t = boost_tasks[cpu]; 1663 boost_tasks[cpu] = NULL; 1664 rcu_torture_enable_rt_throttle(); 1665 mutex_unlock(&boost_mutex); 1666 1667 /* This must be outside of the mutex, otherwise deadlock! */ 1668 torture_stop_kthread(rcu_torture_boost, t); 1669 return 0; 1670 } 1671 1672 static int rcutorture_booster_init(unsigned int cpu) 1673 { 1674 int retval; 1675 1676 if (boost_tasks[cpu] != NULL) 1677 return 0; /* Already created, nothing more to do. */ 1678 1679 /* Don't allow time recalculation while creating a new task. */ 1680 mutex_lock(&boost_mutex); 1681 rcu_torture_disable_rt_throttle(); 1682 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task"); 1683 boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL, 1684 cpu_to_node(cpu), 1685 "rcu_torture_boost"); 1686 if (IS_ERR(boost_tasks[cpu])) { 1687 retval = PTR_ERR(boost_tasks[cpu]); 1688 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed"); 1689 n_rcu_torture_boost_ktrerror++; 1690 boost_tasks[cpu] = NULL; 1691 mutex_unlock(&boost_mutex); 1692 return retval; 1693 } 1694 kthread_bind(boost_tasks[cpu], cpu); 1695 wake_up_process(boost_tasks[cpu]); 1696 mutex_unlock(&boost_mutex); 1697 return 0; 1698 } 1699 1700 /* 1701 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then 1702 * induces a CPU stall for the time specified by stall_cpu. 1703 */ 1704 static int rcu_torture_stall(void *args) 1705 { 1706 int idx; 1707 unsigned long stop_at; 1708 1709 VERBOSE_TOROUT_STRING("rcu_torture_stall task started"); 1710 if (stall_cpu_holdoff > 0) { 1711 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff"); 1712 schedule_timeout_interruptible(stall_cpu_holdoff * HZ); 1713 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff"); 1714 } 1715 if (!kthread_should_stop() && stall_gp_kthread > 0) { 1716 VERBOSE_TOROUT_STRING("rcu_torture_stall begin GP stall"); 1717 rcu_gp_set_torture_wait(stall_gp_kthread * HZ); 1718 for (idx = 0; idx < stall_gp_kthread + 2; idx++) { 1719 if (kthread_should_stop()) 1720 break; 1721 schedule_timeout_uninterruptible(HZ); 1722 } 1723 } 1724 if (!kthread_should_stop() && stall_cpu > 0) { 1725 VERBOSE_TOROUT_STRING("rcu_torture_stall begin CPU stall"); 1726 stop_at = ktime_get_seconds() + stall_cpu; 1727 /* RCU CPU stall is expected behavior in following code. */ 1728 idx = cur_ops->readlock(); 1729 if (stall_cpu_irqsoff) 1730 local_irq_disable(); 1731 else if (!stall_cpu_block) 1732 preempt_disable(); 1733 pr_alert("rcu_torture_stall start on CPU %d.\n", 1734 raw_smp_processor_id()); 1735 while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(), 1736 stop_at)) 1737 if (stall_cpu_block) 1738 schedule_timeout_uninterruptible(HZ); 1739 if (stall_cpu_irqsoff) 1740 local_irq_enable(); 1741 else if (!stall_cpu_block) 1742 preempt_enable(); 1743 cur_ops->readunlock(idx); 1744 } 1745 pr_alert("rcu_torture_stall end.\n"); 1746 torture_shutdown_absorb("rcu_torture_stall"); 1747 while (!kthread_should_stop()) 1748 schedule_timeout_interruptible(10 * HZ); 1749 return 0; 1750 } 1751 1752 /* Spawn CPU-stall kthread, if stall_cpu specified. */ 1753 static int __init rcu_torture_stall_init(void) 1754 { 1755 if (stall_cpu <= 0 && stall_gp_kthread <= 0) 1756 return 0; 1757 return torture_create_kthread(rcu_torture_stall, NULL, stall_task); 1758 } 1759 1760 /* State structure for forward-progress self-propagating RCU callback. */ 1761 struct fwd_cb_state { 1762 struct rcu_head rh; 1763 int stop; 1764 }; 1765 1766 /* 1767 * Forward-progress self-propagating RCU callback function. Because 1768 * callbacks run from softirq, this function is an implicit RCU read-side 1769 * critical section. 1770 */ 1771 static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp) 1772 { 1773 struct fwd_cb_state *fcsp = container_of(rhp, struct fwd_cb_state, rh); 1774 1775 if (READ_ONCE(fcsp->stop)) { 1776 WRITE_ONCE(fcsp->stop, 2); 1777 return; 1778 } 1779 cur_ops->call(&fcsp->rh, rcu_torture_fwd_prog_cb); 1780 } 1781 1782 /* State for continuous-flood RCU callbacks. */ 1783 struct rcu_fwd_cb { 1784 struct rcu_head rh; 1785 struct rcu_fwd_cb *rfc_next; 1786 struct rcu_fwd *rfc_rfp; 1787 int rfc_gps; 1788 }; 1789 1790 #define MAX_FWD_CB_JIFFIES (8 * HZ) /* Maximum CB test duration. */ 1791 #define MIN_FWD_CB_LAUNDERS 3 /* This many CB invocations to count. */ 1792 #define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */ 1793 #define FWD_CBS_HIST_DIV 10 /* Histogram buckets/second. */ 1794 #define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV)) 1795 1796 struct rcu_launder_hist { 1797 long n_launders; 1798 unsigned long launder_gp_seq; 1799 }; 1800 1801 struct rcu_fwd { 1802 spinlock_t rcu_fwd_lock; 1803 struct rcu_fwd_cb *rcu_fwd_cb_head; 1804 struct rcu_fwd_cb **rcu_fwd_cb_tail; 1805 long n_launders_cb; 1806 unsigned long rcu_fwd_startat; 1807 struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST]; 1808 unsigned long rcu_launder_gp_seq_start; 1809 }; 1810 1811 static struct rcu_fwd *rcu_fwds; 1812 static bool rcu_fwd_emergency_stop; 1813 1814 static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp) 1815 { 1816 unsigned long gps; 1817 unsigned long gps_old; 1818 int i; 1819 int j; 1820 1821 for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--) 1822 if (rfp->n_launders_hist[i].n_launders > 0) 1823 break; 1824 pr_alert("%s: Callback-invocation histogram (duration %lu jiffies):", 1825 __func__, jiffies - rfp->rcu_fwd_startat); 1826 gps_old = rfp->rcu_launder_gp_seq_start; 1827 for (j = 0; j <= i; j++) { 1828 gps = rfp->n_launders_hist[j].launder_gp_seq; 1829 pr_cont(" %ds/%d: %ld:%ld", 1830 j + 1, FWD_CBS_HIST_DIV, 1831 rfp->n_launders_hist[j].n_launders, 1832 rcutorture_seq_diff(gps, gps_old)); 1833 gps_old = gps; 1834 } 1835 pr_cont("\n"); 1836 } 1837 1838 /* Callback function for continuous-flood RCU callbacks. */ 1839 static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp) 1840 { 1841 unsigned long flags; 1842 int i; 1843 struct rcu_fwd_cb *rfcp = container_of(rhp, struct rcu_fwd_cb, rh); 1844 struct rcu_fwd_cb **rfcpp; 1845 struct rcu_fwd *rfp = rfcp->rfc_rfp; 1846 1847 rfcp->rfc_next = NULL; 1848 rfcp->rfc_gps++; 1849 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags); 1850 rfcpp = rfp->rcu_fwd_cb_tail; 1851 rfp->rcu_fwd_cb_tail = &rfcp->rfc_next; 1852 WRITE_ONCE(*rfcpp, rfcp); 1853 WRITE_ONCE(rfp->n_launders_cb, rfp->n_launders_cb + 1); 1854 i = ((jiffies - rfp->rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV)); 1855 if (i >= ARRAY_SIZE(rfp->n_launders_hist)) 1856 i = ARRAY_SIZE(rfp->n_launders_hist) - 1; 1857 rfp->n_launders_hist[i].n_launders++; 1858 rfp->n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq(); 1859 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 1860 } 1861 1862 // Give the scheduler a chance, even on nohz_full CPUs. 1863 static void rcu_torture_fwd_prog_cond_resched(unsigned long iter) 1864 { 1865 if (IS_ENABLED(CONFIG_PREEMPTION) && IS_ENABLED(CONFIG_NO_HZ_FULL)) { 1866 // Real call_rcu() floods hit userspace, so emulate that. 1867 if (need_resched() || (iter & 0xfff)) 1868 schedule(); 1869 return; 1870 } 1871 // No userspace emulation: CB invocation throttles call_rcu() 1872 cond_resched(); 1873 } 1874 1875 /* 1876 * Free all callbacks on the rcu_fwd_cb_head list, either because the 1877 * test is over or because we hit an OOM event. 1878 */ 1879 static unsigned long rcu_torture_fwd_prog_cbfree(struct rcu_fwd *rfp) 1880 { 1881 unsigned long flags; 1882 unsigned long freed = 0; 1883 struct rcu_fwd_cb *rfcp; 1884 1885 for (;;) { 1886 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags); 1887 rfcp = rfp->rcu_fwd_cb_head; 1888 if (!rfcp) { 1889 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 1890 break; 1891 } 1892 rfp->rcu_fwd_cb_head = rfcp->rfc_next; 1893 if (!rfp->rcu_fwd_cb_head) 1894 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head; 1895 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 1896 kfree(rfcp); 1897 freed++; 1898 rcu_torture_fwd_prog_cond_resched(freed); 1899 if (tick_nohz_full_enabled()) { 1900 local_irq_save(flags); 1901 rcu_momentary_dyntick_idle(); 1902 local_irq_restore(flags); 1903 } 1904 } 1905 return freed; 1906 } 1907 1908 /* Carry out need_resched()/cond_resched() forward-progress testing. */ 1909 static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp, 1910 int *tested, int *tested_tries) 1911 { 1912 unsigned long cver; 1913 unsigned long dur; 1914 struct fwd_cb_state fcs; 1915 unsigned long gps; 1916 int idx; 1917 int sd; 1918 int sd4; 1919 bool selfpropcb = false; 1920 unsigned long stopat; 1921 static DEFINE_TORTURE_RANDOM(trs); 1922 1923 if (cur_ops->call && cur_ops->sync && cur_ops->cb_barrier) { 1924 init_rcu_head_on_stack(&fcs.rh); 1925 selfpropcb = true; 1926 } 1927 1928 /* Tight loop containing cond_resched(). */ 1929 WRITE_ONCE(rcu_fwd_cb_nodelay, true); 1930 cur_ops->sync(); /* Later readers see above write. */ 1931 if (selfpropcb) { 1932 WRITE_ONCE(fcs.stop, 0); 1933 cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb); 1934 } 1935 cver = READ_ONCE(rcu_torture_current_version); 1936 gps = cur_ops->get_gp_seq(); 1937 sd = cur_ops->stall_dur() + 1; 1938 sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div; 1939 dur = sd4 + torture_random(&trs) % (sd - sd4); 1940 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies); 1941 stopat = rfp->rcu_fwd_startat + dur; 1942 while (time_before(jiffies, stopat) && 1943 !shutdown_time_arrived() && 1944 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 1945 idx = cur_ops->readlock(); 1946 udelay(10); 1947 cur_ops->readunlock(idx); 1948 if (!fwd_progress_need_resched || need_resched()) 1949 cond_resched(); 1950 } 1951 (*tested_tries)++; 1952 if (!time_before(jiffies, stopat) && 1953 !shutdown_time_arrived() && 1954 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 1955 (*tested)++; 1956 cver = READ_ONCE(rcu_torture_current_version) - cver; 1957 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps); 1958 WARN_ON(!cver && gps < 2); 1959 pr_alert("%s: Duration %ld cver %ld gps %ld\n", __func__, dur, cver, gps); 1960 } 1961 if (selfpropcb) { 1962 WRITE_ONCE(fcs.stop, 1); 1963 cur_ops->sync(); /* Wait for running CB to complete. */ 1964 cur_ops->cb_barrier(); /* Wait for queued callbacks. */ 1965 } 1966 1967 if (selfpropcb) { 1968 WARN_ON(READ_ONCE(fcs.stop) != 2); 1969 destroy_rcu_head_on_stack(&fcs.rh); 1970 } 1971 schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */ 1972 WRITE_ONCE(rcu_fwd_cb_nodelay, false); 1973 } 1974 1975 /* Carry out call_rcu() forward-progress testing. */ 1976 static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp) 1977 { 1978 unsigned long cver; 1979 unsigned long flags; 1980 unsigned long gps; 1981 int i; 1982 long n_launders; 1983 long n_launders_cb_snap; 1984 long n_launders_sa; 1985 long n_max_cbs; 1986 long n_max_gps; 1987 struct rcu_fwd_cb *rfcp; 1988 struct rcu_fwd_cb *rfcpn; 1989 unsigned long stopat; 1990 unsigned long stoppedat; 1991 1992 if (READ_ONCE(rcu_fwd_emergency_stop)) 1993 return; /* Get out of the way quickly, no GP wait! */ 1994 if (!cur_ops->call) 1995 return; /* Can't do call_rcu() fwd prog without ->call. */ 1996 1997 /* Loop continuously posting RCU callbacks. */ 1998 WRITE_ONCE(rcu_fwd_cb_nodelay, true); 1999 cur_ops->sync(); /* Later readers see above write. */ 2000 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies); 2001 stopat = rfp->rcu_fwd_startat + MAX_FWD_CB_JIFFIES; 2002 n_launders = 0; 2003 rfp->n_launders_cb = 0; // Hoist initialization for multi-kthread 2004 n_launders_sa = 0; 2005 n_max_cbs = 0; 2006 n_max_gps = 0; 2007 for (i = 0; i < ARRAY_SIZE(rfp->n_launders_hist); i++) 2008 rfp->n_launders_hist[i].n_launders = 0; 2009 cver = READ_ONCE(rcu_torture_current_version); 2010 gps = cur_ops->get_gp_seq(); 2011 rfp->rcu_launder_gp_seq_start = gps; 2012 tick_dep_set_task(current, TICK_DEP_BIT_RCU); 2013 while (time_before(jiffies, stopat) && 2014 !shutdown_time_arrived() && 2015 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 2016 rfcp = READ_ONCE(rfp->rcu_fwd_cb_head); 2017 rfcpn = NULL; 2018 if (rfcp) 2019 rfcpn = READ_ONCE(rfcp->rfc_next); 2020 if (rfcpn) { 2021 if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS && 2022 ++n_max_gps >= MIN_FWD_CBS_LAUNDERED) 2023 break; 2024 rfp->rcu_fwd_cb_head = rfcpn; 2025 n_launders++; 2026 n_launders_sa++; 2027 } else { 2028 rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL); 2029 if (WARN_ON_ONCE(!rfcp)) { 2030 schedule_timeout_interruptible(1); 2031 continue; 2032 } 2033 n_max_cbs++; 2034 n_launders_sa = 0; 2035 rfcp->rfc_gps = 0; 2036 rfcp->rfc_rfp = rfp; 2037 } 2038 cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr); 2039 rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs); 2040 if (tick_nohz_full_enabled()) { 2041 local_irq_save(flags); 2042 rcu_momentary_dyntick_idle(); 2043 local_irq_restore(flags); 2044 } 2045 } 2046 stoppedat = jiffies; 2047 n_launders_cb_snap = READ_ONCE(rfp->n_launders_cb); 2048 cver = READ_ONCE(rcu_torture_current_version) - cver; 2049 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps); 2050 cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */ 2051 (void)rcu_torture_fwd_prog_cbfree(rfp); 2052 2053 if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) && 2054 !shutdown_time_arrived()) { 2055 WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED); 2056 pr_alert("%s Duration %lu barrier: %lu pending %ld n_launders: %ld n_launders_sa: %ld n_max_gps: %ld n_max_cbs: %ld cver %ld gps %ld\n", 2057 __func__, 2058 stoppedat - rfp->rcu_fwd_startat, jiffies - stoppedat, 2059 n_launders + n_max_cbs - n_launders_cb_snap, 2060 n_launders, n_launders_sa, 2061 n_max_gps, n_max_cbs, cver, gps); 2062 rcu_torture_fwd_cb_hist(rfp); 2063 } 2064 schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */ 2065 tick_dep_clear_task(current, TICK_DEP_BIT_RCU); 2066 WRITE_ONCE(rcu_fwd_cb_nodelay, false); 2067 } 2068 2069 2070 /* 2071 * OOM notifier, but this only prints diagnostic information for the 2072 * current forward-progress test. 2073 */ 2074 static int rcutorture_oom_notify(struct notifier_block *self, 2075 unsigned long notused, void *nfreed) 2076 { 2077 struct rcu_fwd *rfp = rcu_fwds; 2078 2079 WARN(1, "%s invoked upon OOM during forward-progress testing.\n", 2080 __func__); 2081 rcu_torture_fwd_cb_hist(rfp); 2082 rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp->rcu_fwd_startat)) / 2); 2083 WRITE_ONCE(rcu_fwd_emergency_stop, true); 2084 smp_mb(); /* Emergency stop before free and wait to avoid hangs. */ 2085 pr_info("%s: Freed %lu RCU callbacks.\n", 2086 __func__, rcu_torture_fwd_prog_cbfree(rfp)); 2087 rcu_barrier(); 2088 pr_info("%s: Freed %lu RCU callbacks.\n", 2089 __func__, rcu_torture_fwd_prog_cbfree(rfp)); 2090 rcu_barrier(); 2091 pr_info("%s: Freed %lu RCU callbacks.\n", 2092 __func__, rcu_torture_fwd_prog_cbfree(rfp)); 2093 smp_mb(); /* Frees before return to avoid redoing OOM. */ 2094 (*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */ 2095 pr_info("%s returning after OOM processing.\n", __func__); 2096 return NOTIFY_OK; 2097 } 2098 2099 static struct notifier_block rcutorture_oom_nb = { 2100 .notifier_call = rcutorture_oom_notify 2101 }; 2102 2103 /* Carry out grace-period forward-progress testing. */ 2104 static int rcu_torture_fwd_prog(void *args) 2105 { 2106 struct rcu_fwd *rfp = args; 2107 int tested = 0; 2108 int tested_tries = 0; 2109 2110 VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started"); 2111 rcu_bind_current_to_nocb(); 2112 if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST)) 2113 set_user_nice(current, MAX_NICE); 2114 do { 2115 schedule_timeout_interruptible(fwd_progress_holdoff * HZ); 2116 WRITE_ONCE(rcu_fwd_emergency_stop, false); 2117 register_oom_notifier(&rcutorture_oom_nb); 2118 if (!IS_ENABLED(CONFIG_TINY_RCU) || 2119 rcu_inkernel_boot_has_ended()) 2120 rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries); 2121 if (rcu_inkernel_boot_has_ended()) 2122 rcu_torture_fwd_prog_cr(rfp); 2123 unregister_oom_notifier(&rcutorture_oom_nb); 2124 2125 /* Avoid slow periods, better to test when busy. */ 2126 stutter_wait("rcu_torture_fwd_prog"); 2127 } while (!torture_must_stop()); 2128 /* Short runs might not contain a valid forward-progress attempt. */ 2129 WARN_ON(!tested && tested_tries >= 5); 2130 pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries); 2131 torture_kthread_stopping("rcu_torture_fwd_prog"); 2132 return 0; 2133 } 2134 2135 /* If forward-progress checking is requested and feasible, spawn the thread. */ 2136 static int __init rcu_torture_fwd_prog_init(void) 2137 { 2138 struct rcu_fwd *rfp; 2139 2140 if (!fwd_progress) 2141 return 0; /* Not requested, so don't do it. */ 2142 if (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0 || 2143 cur_ops == &rcu_busted_ops) { 2144 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test"); 2145 return 0; 2146 } 2147 if (stall_cpu > 0) { 2148 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing"); 2149 if (IS_MODULE(CONFIG_RCU_TORTURE_TESTS)) 2150 return -EINVAL; /* In module, can fail back to user. */ 2151 WARN_ON(1); /* Make sure rcutorture notices conflict. */ 2152 return 0; 2153 } 2154 if (fwd_progress_holdoff <= 0) 2155 fwd_progress_holdoff = 1; 2156 if (fwd_progress_div <= 0) 2157 fwd_progress_div = 4; 2158 rfp = kzalloc(sizeof(*rfp), GFP_KERNEL); 2159 if (!rfp) 2160 return -ENOMEM; 2161 spin_lock_init(&rfp->rcu_fwd_lock); 2162 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head; 2163 return torture_create_kthread(rcu_torture_fwd_prog, rfp, fwd_prog_task); 2164 } 2165 2166 /* Callback function for RCU barrier testing. */ 2167 static void rcu_torture_barrier_cbf(struct rcu_head *rcu) 2168 { 2169 atomic_inc(&barrier_cbs_invoked); 2170 } 2171 2172 /* IPI handler to get callback posted on desired CPU, if online. */ 2173 static void rcu_torture_barrier1cb(void *rcu_void) 2174 { 2175 struct rcu_head *rhp = rcu_void; 2176 2177 cur_ops->call(rhp, rcu_torture_barrier_cbf); 2178 } 2179 2180 /* kthread function to register callbacks used to test RCU barriers. */ 2181 static int rcu_torture_barrier_cbs(void *arg) 2182 { 2183 long myid = (long)arg; 2184 bool lastphase = false; 2185 bool newphase; 2186 struct rcu_head rcu; 2187 2188 init_rcu_head_on_stack(&rcu); 2189 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started"); 2190 set_user_nice(current, MAX_NICE); 2191 do { 2192 wait_event(barrier_cbs_wq[myid], 2193 (newphase = 2194 smp_load_acquire(&barrier_phase)) != lastphase || 2195 torture_must_stop()); 2196 lastphase = newphase; 2197 if (torture_must_stop()) 2198 break; 2199 /* 2200 * The above smp_load_acquire() ensures barrier_phase load 2201 * is ordered before the following ->call(). 2202 */ 2203 if (smp_call_function_single(myid, rcu_torture_barrier1cb, 2204 &rcu, 1)) { 2205 // IPI failed, so use direct call from current CPU. 2206 cur_ops->call(&rcu, rcu_torture_barrier_cbf); 2207 } 2208 if (atomic_dec_and_test(&barrier_cbs_count)) 2209 wake_up(&barrier_wq); 2210 } while (!torture_must_stop()); 2211 if (cur_ops->cb_barrier != NULL) 2212 cur_ops->cb_barrier(); 2213 destroy_rcu_head_on_stack(&rcu); 2214 torture_kthread_stopping("rcu_torture_barrier_cbs"); 2215 return 0; 2216 } 2217 2218 /* kthread function to drive and coordinate RCU barrier testing. */ 2219 static int rcu_torture_barrier(void *arg) 2220 { 2221 int i; 2222 2223 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting"); 2224 do { 2225 atomic_set(&barrier_cbs_invoked, 0); 2226 atomic_set(&barrier_cbs_count, n_barrier_cbs); 2227 /* Ensure barrier_phase ordered after prior assignments. */ 2228 smp_store_release(&barrier_phase, !barrier_phase); 2229 for (i = 0; i < n_barrier_cbs; i++) 2230 wake_up(&barrier_cbs_wq[i]); 2231 wait_event(barrier_wq, 2232 atomic_read(&barrier_cbs_count) == 0 || 2233 torture_must_stop()); 2234 if (torture_must_stop()) 2235 break; 2236 n_barrier_attempts++; 2237 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */ 2238 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) { 2239 n_rcu_torture_barrier_error++; 2240 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n", 2241 atomic_read(&barrier_cbs_invoked), 2242 n_barrier_cbs); 2243 WARN_ON(1); 2244 // Wait manually for the remaining callbacks 2245 i = 0; 2246 do { 2247 if (WARN_ON(i++ > HZ)) 2248 i = INT_MIN; 2249 schedule_timeout_interruptible(1); 2250 cur_ops->cb_barrier(); 2251 } while (atomic_read(&barrier_cbs_invoked) != 2252 n_barrier_cbs && 2253 !torture_must_stop()); 2254 smp_mb(); // Can't trust ordering if broken. 2255 if (!torture_must_stop()) 2256 pr_err("Recovered: barrier_cbs_invoked = %d\n", 2257 atomic_read(&barrier_cbs_invoked)); 2258 } else { 2259 n_barrier_successes++; 2260 } 2261 schedule_timeout_interruptible(HZ / 10); 2262 } while (!torture_must_stop()); 2263 torture_kthread_stopping("rcu_torture_barrier"); 2264 return 0; 2265 } 2266 2267 /* Initialize RCU barrier testing. */ 2268 static int rcu_torture_barrier_init(void) 2269 { 2270 int i; 2271 int ret; 2272 2273 if (n_barrier_cbs <= 0) 2274 return 0; 2275 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) { 2276 pr_alert("%s" TORTURE_FLAG 2277 " Call or barrier ops missing for %s,\n", 2278 torture_type, cur_ops->name); 2279 pr_alert("%s" TORTURE_FLAG 2280 " RCU barrier testing omitted from run.\n", 2281 torture_type); 2282 return 0; 2283 } 2284 atomic_set(&barrier_cbs_count, 0); 2285 atomic_set(&barrier_cbs_invoked, 0); 2286 barrier_cbs_tasks = 2287 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]), 2288 GFP_KERNEL); 2289 barrier_cbs_wq = 2290 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL); 2291 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq) 2292 return -ENOMEM; 2293 for (i = 0; i < n_barrier_cbs; i++) { 2294 init_waitqueue_head(&barrier_cbs_wq[i]); 2295 ret = torture_create_kthread(rcu_torture_barrier_cbs, 2296 (void *)(long)i, 2297 barrier_cbs_tasks[i]); 2298 if (ret) 2299 return ret; 2300 } 2301 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task); 2302 } 2303 2304 /* Clean up after RCU barrier testing. */ 2305 static void rcu_torture_barrier_cleanup(void) 2306 { 2307 int i; 2308 2309 torture_stop_kthread(rcu_torture_barrier, barrier_task); 2310 if (barrier_cbs_tasks != NULL) { 2311 for (i = 0; i < n_barrier_cbs; i++) 2312 torture_stop_kthread(rcu_torture_barrier_cbs, 2313 barrier_cbs_tasks[i]); 2314 kfree(barrier_cbs_tasks); 2315 barrier_cbs_tasks = NULL; 2316 } 2317 if (barrier_cbs_wq != NULL) { 2318 kfree(barrier_cbs_wq); 2319 barrier_cbs_wq = NULL; 2320 } 2321 } 2322 2323 static bool rcu_torture_can_boost(void) 2324 { 2325 static int boost_warn_once; 2326 int prio; 2327 2328 if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2) 2329 return false; 2330 2331 prio = rcu_get_gp_kthreads_prio(); 2332 if (!prio) 2333 return false; 2334 2335 if (prio < 2) { 2336 if (boost_warn_once == 1) 2337 return false; 2338 2339 pr_alert("%s: WARN: RCU kthread priority too low to test boosting. Skipping RCU boost test. Try passing rcutree.kthread_prio > 1 on the kernel command line.\n", KBUILD_MODNAME); 2340 boost_warn_once = 1; 2341 return false; 2342 } 2343 2344 return true; 2345 } 2346 2347 static bool read_exit_child_stop; 2348 static bool read_exit_child_stopped; 2349 static wait_queue_head_t read_exit_wq; 2350 2351 // Child kthread which just does an rcutorture reader and exits. 2352 static int rcu_torture_read_exit_child(void *trsp_in) 2353 { 2354 struct torture_random_state *trsp = trsp_in; 2355 2356 set_user_nice(current, MAX_NICE); 2357 // Minimize time between reading and exiting. 2358 while (!kthread_should_stop()) 2359 schedule_timeout_uninterruptible(1); 2360 (void)rcu_torture_one_read(trsp); 2361 return 0; 2362 } 2363 2364 // Parent kthread which creates and destroys read-exit child kthreads. 2365 static int rcu_torture_read_exit(void *unused) 2366 { 2367 int count = 0; 2368 bool errexit = false; 2369 int i; 2370 struct task_struct *tsp; 2371 DEFINE_TORTURE_RANDOM(trs); 2372 2373 // Allocate and initialize. 2374 set_user_nice(current, MAX_NICE); 2375 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of test"); 2376 2377 // Each pass through this loop does one read-exit episode. 2378 do { 2379 if (++count > read_exit_burst) { 2380 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: End of episode"); 2381 rcu_barrier(); // Wait for task_struct free, avoid OOM. 2382 for (i = 0; i < read_exit_delay; i++) { 2383 schedule_timeout_uninterruptible(HZ); 2384 if (READ_ONCE(read_exit_child_stop)) 2385 break; 2386 } 2387 if (!READ_ONCE(read_exit_child_stop)) 2388 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of episode"); 2389 count = 0; 2390 } 2391 if (READ_ONCE(read_exit_child_stop)) 2392 break; 2393 // Spawn child. 2394 tsp = kthread_run(rcu_torture_read_exit_child, 2395 &trs, "%s", 2396 "rcu_torture_read_exit_child"); 2397 if (IS_ERR(tsp)) { 2398 VERBOSE_TOROUT_ERRSTRING("out of memory"); 2399 errexit = true; 2400 tsp = NULL; 2401 break; 2402 } 2403 cond_resched(); 2404 kthread_stop(tsp); 2405 n_read_exits ++; 2406 stutter_wait("rcu_torture_read_exit"); 2407 } while (!errexit && !READ_ONCE(read_exit_child_stop)); 2408 2409 // Clean up and exit. 2410 smp_store_release(&read_exit_child_stopped, true); // After reaping. 2411 smp_mb(); // Store before wakeup. 2412 wake_up(&read_exit_wq); 2413 while (!torture_must_stop()) 2414 schedule_timeout_uninterruptible(1); 2415 torture_kthread_stopping("rcu_torture_read_exit"); 2416 return 0; 2417 } 2418 2419 static int rcu_torture_read_exit_init(void) 2420 { 2421 if (read_exit_burst <= 0) 2422 return -EINVAL; 2423 init_waitqueue_head(&read_exit_wq); 2424 read_exit_child_stop = false; 2425 read_exit_child_stopped = false; 2426 return torture_create_kthread(rcu_torture_read_exit, NULL, 2427 read_exit_task); 2428 } 2429 2430 static void rcu_torture_read_exit_cleanup(void) 2431 { 2432 if (!read_exit_task) 2433 return; 2434 WRITE_ONCE(read_exit_child_stop, true); 2435 smp_mb(); // Above write before wait. 2436 wait_event(read_exit_wq, smp_load_acquire(&read_exit_child_stopped)); 2437 torture_stop_kthread(rcutorture_read_exit, read_exit_task); 2438 } 2439 2440 static enum cpuhp_state rcutor_hp; 2441 2442 static void 2443 rcu_torture_cleanup(void) 2444 { 2445 int firsttime; 2446 int flags = 0; 2447 unsigned long gp_seq = 0; 2448 int i; 2449 2450 if (torture_cleanup_begin()) { 2451 if (cur_ops->cb_barrier != NULL) 2452 cur_ops->cb_barrier(); 2453 return; 2454 } 2455 if (!cur_ops) { 2456 torture_cleanup_end(); 2457 return; 2458 } 2459 2460 show_rcu_gp_kthreads(); 2461 rcu_torture_read_exit_cleanup(); 2462 rcu_torture_barrier_cleanup(); 2463 torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_task); 2464 torture_stop_kthread(rcu_torture_stall, stall_task); 2465 torture_stop_kthread(rcu_torture_writer, writer_task); 2466 2467 if (reader_tasks) { 2468 for (i = 0; i < nrealreaders; i++) 2469 torture_stop_kthread(rcu_torture_reader, 2470 reader_tasks[i]); 2471 kfree(reader_tasks); 2472 } 2473 2474 if (fakewriter_tasks) { 2475 for (i = 0; i < nfakewriters; i++) { 2476 torture_stop_kthread(rcu_torture_fakewriter, 2477 fakewriter_tasks[i]); 2478 } 2479 kfree(fakewriter_tasks); 2480 fakewriter_tasks = NULL; 2481 } 2482 2483 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq); 2484 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq); 2485 pr_alert("%s: End-test grace-period state: g%lu f%#x\n", 2486 cur_ops->name, gp_seq, flags); 2487 torture_stop_kthread(rcu_torture_stats, stats_task); 2488 torture_stop_kthread(rcu_torture_fqs, fqs_task); 2489 if (rcu_torture_can_boost()) 2490 cpuhp_remove_state(rcutor_hp); 2491 2492 /* 2493 * Wait for all RCU callbacks to fire, then do torture-type-specific 2494 * cleanup operations. 2495 */ 2496 if (cur_ops->cb_barrier != NULL) 2497 cur_ops->cb_barrier(); 2498 if (cur_ops->cleanup != NULL) 2499 cur_ops->cleanup(); 2500 2501 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */ 2502 2503 if (err_segs_recorded) { 2504 pr_alert("Failure/close-call rcutorture reader segments:\n"); 2505 if (rt_read_nsegs == 0) 2506 pr_alert("\t: No segments recorded!!!\n"); 2507 firsttime = 1; 2508 for (i = 0; i < rt_read_nsegs; i++) { 2509 pr_alert("\t%d: %#x ", i, err_segs[i].rt_readstate); 2510 if (err_segs[i].rt_delay_jiffies != 0) { 2511 pr_cont("%s%ldjiffies", firsttime ? "" : "+", 2512 err_segs[i].rt_delay_jiffies); 2513 firsttime = 0; 2514 } 2515 if (err_segs[i].rt_delay_ms != 0) { 2516 pr_cont("%s%ldms", firsttime ? "" : "+", 2517 err_segs[i].rt_delay_ms); 2518 firsttime = 0; 2519 } 2520 if (err_segs[i].rt_delay_us != 0) { 2521 pr_cont("%s%ldus", firsttime ? "" : "+", 2522 err_segs[i].rt_delay_us); 2523 firsttime = 0; 2524 } 2525 pr_cont("%s\n", 2526 err_segs[i].rt_preempted ? "preempted" : ""); 2527 2528 } 2529 } 2530 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error) 2531 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE"); 2532 else if (torture_onoff_failures()) 2533 rcu_torture_print_module_parms(cur_ops, 2534 "End of test: RCU_HOTPLUG"); 2535 else 2536 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS"); 2537 torture_cleanup_end(); 2538 } 2539 2540 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD 2541 static void rcu_torture_leak_cb(struct rcu_head *rhp) 2542 { 2543 } 2544 2545 static void rcu_torture_err_cb(struct rcu_head *rhp) 2546 { 2547 /* 2548 * This -might- happen due to race conditions, but is unlikely. 2549 * The scenario that leads to this happening is that the 2550 * first of the pair of duplicate callbacks is queued, 2551 * someone else starts a grace period that includes that 2552 * callback, then the second of the pair must wait for the 2553 * next grace period. Unlikely, but can happen. If it 2554 * does happen, the debug-objects subsystem won't have splatted. 2555 */ 2556 pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME); 2557 } 2558 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 2559 2560 /* 2561 * Verify that double-free causes debug-objects to complain, but only 2562 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test 2563 * cannot be carried out. 2564 */ 2565 static void rcu_test_debug_objects(void) 2566 { 2567 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD 2568 struct rcu_head rh1; 2569 struct rcu_head rh2; 2570 2571 init_rcu_head_on_stack(&rh1); 2572 init_rcu_head_on_stack(&rh2); 2573 pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME); 2574 2575 /* Try to queue the rh2 pair of callbacks for the same grace period. */ 2576 preempt_disable(); /* Prevent preemption from interrupting test. */ 2577 rcu_read_lock(); /* Make it impossible to finish a grace period. */ 2578 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */ 2579 local_irq_disable(); /* Make it harder to start a new grace period. */ 2580 call_rcu(&rh2, rcu_torture_leak_cb); 2581 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */ 2582 local_irq_enable(); 2583 rcu_read_unlock(); 2584 preempt_enable(); 2585 2586 /* Wait for them all to get done so we can safely return. */ 2587 rcu_barrier(); 2588 pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME); 2589 destroy_rcu_head_on_stack(&rh1); 2590 destroy_rcu_head_on_stack(&rh2); 2591 #else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 2592 pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME); 2593 #endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 2594 } 2595 2596 static void rcutorture_sync(void) 2597 { 2598 static unsigned long n; 2599 2600 if (cur_ops->sync && !(++n & 0xfff)) 2601 cur_ops->sync(); 2602 } 2603 2604 static int __init 2605 rcu_torture_init(void) 2606 { 2607 long i; 2608 int cpu; 2609 int firsterr = 0; 2610 static struct rcu_torture_ops *torture_ops[] = { 2611 &rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops, 2612 &busted_srcud_ops, &tasks_ops, &tasks_rude_ops, 2613 &tasks_tracing_ops, &trivial_ops, 2614 }; 2615 2616 if (!torture_init_begin(torture_type, verbose)) 2617 return -EBUSY; 2618 2619 /* Process args and tell the world that the torturer is on the job. */ 2620 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) { 2621 cur_ops = torture_ops[i]; 2622 if (strcmp(torture_type, cur_ops->name) == 0) 2623 break; 2624 } 2625 if (i == ARRAY_SIZE(torture_ops)) { 2626 pr_alert("rcu-torture: invalid torture type: \"%s\"\n", 2627 torture_type); 2628 pr_alert("rcu-torture types:"); 2629 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) 2630 pr_cont(" %s", torture_ops[i]->name); 2631 pr_cont("\n"); 2632 WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST)); 2633 firsterr = -EINVAL; 2634 cur_ops = NULL; 2635 goto unwind; 2636 } 2637 if (cur_ops->fqs == NULL && fqs_duration != 0) { 2638 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n"); 2639 fqs_duration = 0; 2640 } 2641 if (cur_ops->init) 2642 cur_ops->init(); 2643 2644 if (nreaders >= 0) { 2645 nrealreaders = nreaders; 2646 } else { 2647 nrealreaders = num_online_cpus() - 2 - nreaders; 2648 if (nrealreaders <= 0) 2649 nrealreaders = 1; 2650 } 2651 rcu_torture_print_module_parms(cur_ops, "Start of test"); 2652 2653 /* Set up the freelist. */ 2654 2655 INIT_LIST_HEAD(&rcu_torture_freelist); 2656 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) { 2657 rcu_tortures[i].rtort_mbtest = 0; 2658 list_add_tail(&rcu_tortures[i].rtort_free, 2659 &rcu_torture_freelist); 2660 } 2661 2662 /* Initialize the statistics so that each run gets its own numbers. */ 2663 2664 rcu_torture_current = NULL; 2665 rcu_torture_current_version = 0; 2666 atomic_set(&n_rcu_torture_alloc, 0); 2667 atomic_set(&n_rcu_torture_alloc_fail, 0); 2668 atomic_set(&n_rcu_torture_free, 0); 2669 atomic_set(&n_rcu_torture_mberror, 0); 2670 atomic_set(&n_rcu_torture_error, 0); 2671 n_rcu_torture_barrier_error = 0; 2672 n_rcu_torture_boost_ktrerror = 0; 2673 n_rcu_torture_boost_rterror = 0; 2674 n_rcu_torture_boost_failure = 0; 2675 n_rcu_torture_boosts = 0; 2676 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 2677 atomic_set(&rcu_torture_wcount[i], 0); 2678 for_each_possible_cpu(cpu) { 2679 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 2680 per_cpu(rcu_torture_count, cpu)[i] = 0; 2681 per_cpu(rcu_torture_batch, cpu)[i] = 0; 2682 } 2683 } 2684 err_segs_recorded = 0; 2685 rt_read_nsegs = 0; 2686 2687 /* Start up the kthreads. */ 2688 2689 firsterr = torture_create_kthread(rcu_torture_writer, NULL, 2690 writer_task); 2691 if (firsterr) 2692 goto unwind; 2693 if (nfakewriters > 0) { 2694 fakewriter_tasks = kcalloc(nfakewriters, 2695 sizeof(fakewriter_tasks[0]), 2696 GFP_KERNEL); 2697 if (fakewriter_tasks == NULL) { 2698 VERBOSE_TOROUT_ERRSTRING("out of memory"); 2699 firsterr = -ENOMEM; 2700 goto unwind; 2701 } 2702 } 2703 for (i = 0; i < nfakewriters; i++) { 2704 firsterr = torture_create_kthread(rcu_torture_fakewriter, 2705 NULL, fakewriter_tasks[i]); 2706 if (firsterr) 2707 goto unwind; 2708 } 2709 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]), 2710 GFP_KERNEL); 2711 if (reader_tasks == NULL) { 2712 VERBOSE_TOROUT_ERRSTRING("out of memory"); 2713 firsterr = -ENOMEM; 2714 goto unwind; 2715 } 2716 for (i = 0; i < nrealreaders; i++) { 2717 firsterr = torture_create_kthread(rcu_torture_reader, (void *)i, 2718 reader_tasks[i]); 2719 if (firsterr) 2720 goto unwind; 2721 } 2722 if (stat_interval > 0) { 2723 firsterr = torture_create_kthread(rcu_torture_stats, NULL, 2724 stats_task); 2725 if (firsterr) 2726 goto unwind; 2727 } 2728 if (test_no_idle_hz && shuffle_interval > 0) { 2729 firsterr = torture_shuffle_init(shuffle_interval * HZ); 2730 if (firsterr) 2731 goto unwind; 2732 } 2733 if (stutter < 0) 2734 stutter = 0; 2735 if (stutter) { 2736 int t; 2737 2738 t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ; 2739 firsterr = torture_stutter_init(stutter * HZ, t); 2740 if (firsterr) 2741 goto unwind; 2742 } 2743 if (fqs_duration < 0) 2744 fqs_duration = 0; 2745 if (fqs_duration) { 2746 /* Create the fqs thread */ 2747 firsterr = torture_create_kthread(rcu_torture_fqs, NULL, 2748 fqs_task); 2749 if (firsterr) 2750 goto unwind; 2751 } 2752 if (test_boost_interval < 1) 2753 test_boost_interval = 1; 2754 if (test_boost_duration < 2) 2755 test_boost_duration = 2; 2756 if (rcu_torture_can_boost()) { 2757 2758 boost_starttime = jiffies + test_boost_interval * HZ; 2759 2760 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE", 2761 rcutorture_booster_init, 2762 rcutorture_booster_cleanup); 2763 if (firsterr < 0) 2764 goto unwind; 2765 rcutor_hp = firsterr; 2766 } 2767 shutdown_jiffies = jiffies + shutdown_secs * HZ; 2768 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup); 2769 if (firsterr) 2770 goto unwind; 2771 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval, 2772 rcutorture_sync); 2773 if (firsterr) 2774 goto unwind; 2775 firsterr = rcu_torture_stall_init(); 2776 if (firsterr) 2777 goto unwind; 2778 firsterr = rcu_torture_fwd_prog_init(); 2779 if (firsterr) 2780 goto unwind; 2781 firsterr = rcu_torture_barrier_init(); 2782 if (firsterr) 2783 goto unwind; 2784 firsterr = rcu_torture_read_exit_init(); 2785 if (firsterr) 2786 goto unwind; 2787 if (object_debug) 2788 rcu_test_debug_objects(); 2789 torture_init_end(); 2790 return 0; 2791 2792 unwind: 2793 torture_init_end(); 2794 rcu_torture_cleanup(); 2795 return firsterr; 2796 } 2797 2798 module_init(rcu_torture_init); 2799 module_exit(rcu_torture_cleanup); 2800