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 /* Bits for ->extendables field, extendables param, and related definitions. */ 56 #define RCUTORTURE_RDR_SHIFT 8 /* Put SRCU index in upper bits. */ 57 #define RCUTORTURE_RDR_MASK ((1 << RCUTORTURE_RDR_SHIFT) - 1) 58 #define RCUTORTURE_RDR_BH 0x01 /* Extend readers by disabling bh. */ 59 #define RCUTORTURE_RDR_IRQ 0x02 /* ... disabling interrupts. */ 60 #define RCUTORTURE_RDR_PREEMPT 0x04 /* ... disabling preemption. */ 61 #define RCUTORTURE_RDR_RBH 0x08 /* ... rcu_read_lock_bh(). */ 62 #define RCUTORTURE_RDR_SCHED 0x10 /* ... rcu_read_lock_sched(). */ 63 #define RCUTORTURE_RDR_RCU 0x20 /* ... entering another RCU reader. */ 64 #define RCUTORTURE_RDR_NBITS 6 /* Number of bits defined above. */ 65 #define RCUTORTURE_MAX_EXTEND \ 66 (RCUTORTURE_RDR_BH | RCUTORTURE_RDR_IRQ | RCUTORTURE_RDR_PREEMPT | \ 67 RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED) 68 #define RCUTORTURE_RDR_MAX_LOOPS 0x7 /* Maximum reader extensions. */ 69 /* Must be power of two minus one. */ 70 #define RCUTORTURE_RDR_MAX_SEGS (RCUTORTURE_RDR_MAX_LOOPS + 3) 71 72 torture_param(int, extendables, RCUTORTURE_MAX_EXTEND, 73 "Extend readers by disabling bh (1), irqs (2), or preempt (4)"); 74 torture_param(int, fqs_duration, 0, 75 "Duration of fqs bursts (us), 0 to disable"); 76 torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)"); 77 torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)"); 78 torture_param(bool, fwd_progress, 1, "Test grace-period forward progress"); 79 torture_param(int, fwd_progress_div, 4, "Fraction of CPU stall to wait"); 80 torture_param(int, fwd_progress_holdoff, 60, 81 "Time between forward-progress tests (s)"); 82 torture_param(bool, fwd_progress_need_resched, 1, 83 "Hide cond_resched() behind need_resched()"); 84 torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives"); 85 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives"); 86 torture_param(bool, gp_normal, false, 87 "Use normal (non-expedited) GP wait primitives"); 88 torture_param(bool, gp_poll, false, "Use polling GP wait primitives"); 89 torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives"); 90 torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers"); 91 torture_param(int, leakpointer, 0, "Leak pointer dereferences from readers"); 92 torture_param(int, n_barrier_cbs, 0, 93 "# of callbacks/kthreads for barrier testing"); 94 torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads"); 95 torture_param(int, nreaders, -1, "Number of RCU reader threads"); 96 torture_param(int, object_debug, 0, 97 "Enable debug-object double call_rcu() testing"); 98 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)"); 99 torture_param(int, onoff_interval, 0, 100 "Time between CPU hotplugs (jiffies), 0=disable"); 101 torture_param(int, nocbs_nthreads, 0, "Number of NOCB toggle threads, 0 to disable"); 102 torture_param(int, nocbs_toggle, 1000, "Time between toggling nocb state (ms)"); 103 torture_param(int, read_exit_delay, 13, 104 "Delay between read-then-exit episodes (s)"); 105 torture_param(int, read_exit_burst, 16, 106 "# of read-then-exit bursts per episode, zero to disable"); 107 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles"); 108 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable."); 109 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable."); 110 torture_param(int, stall_cpu_holdoff, 10, 111 "Time to wait before starting stall (s)."); 112 torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling."); 113 torture_param(int, stall_cpu_block, 0, "Sleep while stalling."); 114 torture_param(int, stall_gp_kthread, 0, 115 "Grace-period kthread stall duration (s)."); 116 torture_param(int, stat_interval, 60, 117 "Number of seconds between stats printk()s"); 118 torture_param(int, stutter, 5, "Number of seconds to run/halt test"); 119 torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes."); 120 torture_param(int, test_boost_duration, 4, 121 "Duration of each boost test, seconds."); 122 torture_param(int, test_boost_interval, 7, 123 "Interval between boost tests, seconds."); 124 torture_param(bool, test_no_idle_hz, true, 125 "Test support for tickless idle CPUs"); 126 torture_param(int, verbose, 1, 127 "Enable verbose debugging printk()s"); 128 129 static char *torture_type = "rcu"; 130 module_param(torture_type, charp, 0444); 131 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, srcu, ...)"); 132 133 static int nrealnocbers; 134 static int nrealreaders; 135 static struct task_struct *writer_task; 136 static struct task_struct **fakewriter_tasks; 137 static struct task_struct **reader_tasks; 138 static struct task_struct **nocb_tasks; 139 static struct task_struct *stats_task; 140 static struct task_struct *fqs_task; 141 static struct task_struct *boost_tasks[NR_CPUS]; 142 static struct task_struct *stall_task; 143 static struct task_struct *fwd_prog_task; 144 static struct task_struct **barrier_cbs_tasks; 145 static struct task_struct *barrier_task; 146 static struct task_struct *read_exit_task; 147 148 #define RCU_TORTURE_PIPE_LEN 10 149 150 // Mailbox-like structure to check RCU global memory ordering. 151 struct rcu_torture_reader_check { 152 unsigned long rtc_myloops; 153 int rtc_chkrdr; 154 unsigned long rtc_chkloops; 155 int rtc_ready; 156 struct rcu_torture_reader_check *rtc_assigner; 157 } ____cacheline_internodealigned_in_smp; 158 159 // Update-side data structure used to check RCU readers. 160 struct rcu_torture { 161 struct rcu_head rtort_rcu; 162 int rtort_pipe_count; 163 struct list_head rtort_free; 164 int rtort_mbtest; 165 struct rcu_torture_reader_check *rtort_chkp; 166 }; 167 168 static LIST_HEAD(rcu_torture_freelist); 169 static struct rcu_torture __rcu *rcu_torture_current; 170 static unsigned long rcu_torture_current_version; 171 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN]; 172 static DEFINE_SPINLOCK(rcu_torture_lock); 173 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count); 174 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch); 175 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1]; 176 static struct rcu_torture_reader_check *rcu_torture_reader_mbchk; 177 static atomic_t n_rcu_torture_alloc; 178 static atomic_t n_rcu_torture_alloc_fail; 179 static atomic_t n_rcu_torture_free; 180 static atomic_t n_rcu_torture_mberror; 181 static atomic_t n_rcu_torture_mbchk_fail; 182 static atomic_t n_rcu_torture_mbchk_tries; 183 static atomic_t n_rcu_torture_error; 184 static long n_rcu_torture_barrier_error; 185 static long n_rcu_torture_boost_ktrerror; 186 static long n_rcu_torture_boost_rterror; 187 static long n_rcu_torture_boost_failure; 188 static long n_rcu_torture_boosts; 189 static atomic_long_t n_rcu_torture_timers; 190 static long n_barrier_attempts; 191 static long n_barrier_successes; /* did rcu_barrier test succeed? */ 192 static unsigned long n_read_exits; 193 static struct list_head rcu_torture_removed; 194 static unsigned long shutdown_jiffies; 195 static unsigned long start_gp_seq; 196 static atomic_long_t n_nocb_offload; 197 static atomic_long_t n_nocb_deoffload; 198 199 static int rcu_torture_writer_state; 200 #define RTWS_FIXED_DELAY 0 201 #define RTWS_DELAY 1 202 #define RTWS_REPLACE 2 203 #define RTWS_DEF_FREE 3 204 #define RTWS_EXP_SYNC 4 205 #define RTWS_COND_GET 5 206 #define RTWS_COND_SYNC 6 207 #define RTWS_POLL_GET 7 208 #define RTWS_POLL_WAIT 8 209 #define RTWS_SYNC 9 210 #define RTWS_STUTTER 10 211 #define RTWS_STOPPING 11 212 static const char * const rcu_torture_writer_state_names[] = { 213 "RTWS_FIXED_DELAY", 214 "RTWS_DELAY", 215 "RTWS_REPLACE", 216 "RTWS_DEF_FREE", 217 "RTWS_EXP_SYNC", 218 "RTWS_COND_GET", 219 "RTWS_COND_SYNC", 220 "RTWS_POLL_GET", 221 "RTWS_POLL_WAIT", 222 "RTWS_SYNC", 223 "RTWS_STUTTER", 224 "RTWS_STOPPING", 225 }; 226 227 /* Record reader segment types and duration for first failing read. */ 228 struct rt_read_seg { 229 int rt_readstate; 230 unsigned long rt_delay_jiffies; 231 unsigned long rt_delay_ms; 232 unsigned long rt_delay_us; 233 bool rt_preempted; 234 }; 235 static int err_segs_recorded; 236 static struct rt_read_seg err_segs[RCUTORTURE_RDR_MAX_SEGS]; 237 static int rt_read_nsegs; 238 239 static const char *rcu_torture_writer_state_getname(void) 240 { 241 unsigned int i = READ_ONCE(rcu_torture_writer_state); 242 243 if (i >= ARRAY_SIZE(rcu_torture_writer_state_names)) 244 return "???"; 245 return rcu_torture_writer_state_names[i]; 246 } 247 248 #ifdef CONFIG_RCU_TRACE 249 static u64 notrace rcu_trace_clock_local(void) 250 { 251 u64 ts = trace_clock_local(); 252 253 (void)do_div(ts, NSEC_PER_USEC); 254 return ts; 255 } 256 #else /* #ifdef CONFIG_RCU_TRACE */ 257 static u64 notrace rcu_trace_clock_local(void) 258 { 259 return 0ULL; 260 } 261 #endif /* #else #ifdef CONFIG_RCU_TRACE */ 262 263 /* 264 * Stop aggressive CPU-hog tests a bit before the end of the test in order 265 * to avoid interfering with test shutdown. 266 */ 267 static bool shutdown_time_arrived(void) 268 { 269 return shutdown_secs && time_after(jiffies, shutdown_jiffies - 30 * HZ); 270 } 271 272 static unsigned long boost_starttime; /* jiffies of next boost test start. */ 273 static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */ 274 /* and boost task create/destroy. */ 275 static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */ 276 static bool barrier_phase; /* Test phase. */ 277 static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */ 278 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */ 279 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq); 280 281 static bool rcu_fwd_cb_nodelay; /* Short rcu_torture_delay() delays. */ 282 283 /* 284 * Allocate an element from the rcu_tortures pool. 285 */ 286 static struct rcu_torture * 287 rcu_torture_alloc(void) 288 { 289 struct list_head *p; 290 291 spin_lock_bh(&rcu_torture_lock); 292 if (list_empty(&rcu_torture_freelist)) { 293 atomic_inc(&n_rcu_torture_alloc_fail); 294 spin_unlock_bh(&rcu_torture_lock); 295 return NULL; 296 } 297 atomic_inc(&n_rcu_torture_alloc); 298 p = rcu_torture_freelist.next; 299 list_del_init(p); 300 spin_unlock_bh(&rcu_torture_lock); 301 return container_of(p, struct rcu_torture, rtort_free); 302 } 303 304 /* 305 * Free an element to the rcu_tortures pool. 306 */ 307 static void 308 rcu_torture_free(struct rcu_torture *p) 309 { 310 atomic_inc(&n_rcu_torture_free); 311 spin_lock_bh(&rcu_torture_lock); 312 list_add_tail(&p->rtort_free, &rcu_torture_freelist); 313 spin_unlock_bh(&rcu_torture_lock); 314 } 315 316 /* 317 * Operations vector for selecting different types of tests. 318 */ 319 320 struct rcu_torture_ops { 321 int ttype; 322 void (*init)(void); 323 void (*cleanup)(void); 324 int (*readlock)(void); 325 void (*read_delay)(struct torture_random_state *rrsp, 326 struct rt_read_seg *rtrsp); 327 void (*readunlock)(int idx); 328 int (*readlock_held)(void); 329 unsigned long (*get_gp_seq)(void); 330 unsigned long (*gp_diff)(unsigned long new, unsigned long old); 331 void (*deferred_free)(struct rcu_torture *p); 332 void (*sync)(void); 333 void (*exp_sync)(void); 334 unsigned long (*get_gp_state)(void); 335 unsigned long (*start_gp_poll)(void); 336 bool (*poll_gp_state)(unsigned long oldstate); 337 void (*cond_sync)(unsigned long oldstate); 338 call_rcu_func_t call; 339 void (*cb_barrier)(void); 340 void (*fqs)(void); 341 void (*stats)(void); 342 void (*gp_kthread_dbg)(void); 343 bool (*check_boost_failed)(unsigned long gp_state, int *cpup); 344 int (*stall_dur)(void); 345 int irq_capable; 346 int can_boost; 347 int extendables; 348 int slow_gps; 349 const char *name; 350 }; 351 352 static struct rcu_torture_ops *cur_ops; 353 354 /* 355 * Definitions for rcu torture testing. 356 */ 357 358 static int torture_readlock_not_held(void) 359 { 360 return rcu_read_lock_bh_held() || rcu_read_lock_sched_held(); 361 } 362 363 static int rcu_torture_read_lock(void) __acquires(RCU) 364 { 365 rcu_read_lock(); 366 return 0; 367 } 368 369 static void 370 rcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp) 371 { 372 unsigned long started; 373 unsigned long completed; 374 const unsigned long shortdelay_us = 200; 375 unsigned long longdelay_ms = 300; 376 unsigned long long ts; 377 378 /* We want a short delay sometimes to make a reader delay the grace 379 * period, and we want a long delay occasionally to trigger 380 * force_quiescent_state. */ 381 382 if (!READ_ONCE(rcu_fwd_cb_nodelay) && 383 !(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) { 384 started = cur_ops->get_gp_seq(); 385 ts = rcu_trace_clock_local(); 386 if (preempt_count() & (SOFTIRQ_MASK | HARDIRQ_MASK)) 387 longdelay_ms = 5; /* Avoid triggering BH limits. */ 388 mdelay(longdelay_ms); 389 rtrsp->rt_delay_ms = longdelay_ms; 390 completed = cur_ops->get_gp_seq(); 391 do_trace_rcu_torture_read(cur_ops->name, NULL, ts, 392 started, completed); 393 } 394 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) { 395 udelay(shortdelay_us); 396 rtrsp->rt_delay_us = shortdelay_us; 397 } 398 if (!preempt_count() && 399 !(torture_random(rrsp) % (nrealreaders * 500))) { 400 torture_preempt_schedule(); /* QS only if preemptible. */ 401 rtrsp->rt_preempted = true; 402 } 403 } 404 405 static void rcu_torture_read_unlock(int idx) __releases(RCU) 406 { 407 rcu_read_unlock(); 408 } 409 410 /* 411 * Update callback in the pipe. This should be invoked after a grace period. 412 */ 413 static bool 414 rcu_torture_pipe_update_one(struct rcu_torture *rp) 415 { 416 int i; 417 struct rcu_torture_reader_check *rtrcp = READ_ONCE(rp->rtort_chkp); 418 419 if (rtrcp) { 420 WRITE_ONCE(rp->rtort_chkp, NULL); 421 smp_store_release(&rtrcp->rtc_ready, 1); // Pair with smp_load_acquire(). 422 } 423 i = READ_ONCE(rp->rtort_pipe_count); 424 if (i > RCU_TORTURE_PIPE_LEN) 425 i = RCU_TORTURE_PIPE_LEN; 426 atomic_inc(&rcu_torture_wcount[i]); 427 WRITE_ONCE(rp->rtort_pipe_count, i + 1); 428 if (rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) { 429 rp->rtort_mbtest = 0; 430 return true; 431 } 432 return false; 433 } 434 435 /* 436 * Update all callbacks in the pipe. Suitable for synchronous grace-period 437 * primitives. 438 */ 439 static void 440 rcu_torture_pipe_update(struct rcu_torture *old_rp) 441 { 442 struct rcu_torture *rp; 443 struct rcu_torture *rp1; 444 445 if (old_rp) 446 list_add(&old_rp->rtort_free, &rcu_torture_removed); 447 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) { 448 if (rcu_torture_pipe_update_one(rp)) { 449 list_del(&rp->rtort_free); 450 rcu_torture_free(rp); 451 } 452 } 453 } 454 455 static void 456 rcu_torture_cb(struct rcu_head *p) 457 { 458 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu); 459 460 if (torture_must_stop_irq()) { 461 /* Test is ending, just drop callbacks on the floor. */ 462 /* The next initialization will pick up the pieces. */ 463 return; 464 } 465 if (rcu_torture_pipe_update_one(rp)) 466 rcu_torture_free(rp); 467 else 468 cur_ops->deferred_free(rp); 469 } 470 471 static unsigned long rcu_no_completed(void) 472 { 473 return 0; 474 } 475 476 static void rcu_torture_deferred_free(struct rcu_torture *p) 477 { 478 call_rcu(&p->rtort_rcu, rcu_torture_cb); 479 } 480 481 static void rcu_sync_torture_init(void) 482 { 483 INIT_LIST_HEAD(&rcu_torture_removed); 484 } 485 486 static struct rcu_torture_ops rcu_ops = { 487 .ttype = RCU_FLAVOR, 488 .init = rcu_sync_torture_init, 489 .readlock = rcu_torture_read_lock, 490 .read_delay = rcu_read_delay, 491 .readunlock = rcu_torture_read_unlock, 492 .readlock_held = torture_readlock_not_held, 493 .get_gp_seq = rcu_get_gp_seq, 494 .gp_diff = rcu_seq_diff, 495 .deferred_free = rcu_torture_deferred_free, 496 .sync = synchronize_rcu, 497 .exp_sync = synchronize_rcu_expedited, 498 .get_gp_state = get_state_synchronize_rcu, 499 .start_gp_poll = start_poll_synchronize_rcu, 500 .poll_gp_state = poll_state_synchronize_rcu, 501 .cond_sync = cond_synchronize_rcu, 502 .call = call_rcu, 503 .cb_barrier = rcu_barrier, 504 .fqs = rcu_force_quiescent_state, 505 .stats = NULL, 506 .gp_kthread_dbg = show_rcu_gp_kthreads, 507 .check_boost_failed = rcu_check_boost_fail, 508 .stall_dur = rcu_jiffies_till_stall_check, 509 .irq_capable = 1, 510 .can_boost = IS_ENABLED(CONFIG_RCU_BOOST), 511 .extendables = RCUTORTURE_MAX_EXTEND, 512 .name = "rcu" 513 }; 514 515 /* 516 * Don't even think about trying any of these in real life!!! 517 * The names includes "busted", and they really means it! 518 * The only purpose of these functions is to provide a buggy RCU 519 * implementation to make sure that rcutorture correctly emits 520 * buggy-RCU error messages. 521 */ 522 static void rcu_busted_torture_deferred_free(struct rcu_torture *p) 523 { 524 /* This is a deliberate bug for testing purposes only! */ 525 rcu_torture_cb(&p->rtort_rcu); 526 } 527 528 static void synchronize_rcu_busted(void) 529 { 530 /* This is a deliberate bug for testing purposes only! */ 531 } 532 533 static void 534 call_rcu_busted(struct rcu_head *head, rcu_callback_t func) 535 { 536 /* This is a deliberate bug for testing purposes only! */ 537 func(head); 538 } 539 540 static struct rcu_torture_ops rcu_busted_ops = { 541 .ttype = INVALID_RCU_FLAVOR, 542 .init = rcu_sync_torture_init, 543 .readlock = rcu_torture_read_lock, 544 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 545 .readunlock = rcu_torture_read_unlock, 546 .readlock_held = torture_readlock_not_held, 547 .get_gp_seq = rcu_no_completed, 548 .deferred_free = rcu_busted_torture_deferred_free, 549 .sync = synchronize_rcu_busted, 550 .exp_sync = synchronize_rcu_busted, 551 .call = call_rcu_busted, 552 .cb_barrier = NULL, 553 .fqs = NULL, 554 .stats = NULL, 555 .irq_capable = 1, 556 .name = "busted" 557 }; 558 559 /* 560 * Definitions for srcu torture testing. 561 */ 562 563 DEFINE_STATIC_SRCU(srcu_ctl); 564 static struct srcu_struct srcu_ctld; 565 static struct srcu_struct *srcu_ctlp = &srcu_ctl; 566 567 static int srcu_torture_read_lock(void) __acquires(srcu_ctlp) 568 { 569 return srcu_read_lock(srcu_ctlp); 570 } 571 572 static void 573 srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp) 574 { 575 long delay; 576 const long uspertick = 1000000 / HZ; 577 const long longdelay = 10; 578 579 /* We want there to be long-running readers, but not all the time. */ 580 581 delay = torture_random(rrsp) % 582 (nrealreaders * 2 * longdelay * uspertick); 583 if (!delay && in_task()) { 584 schedule_timeout_interruptible(longdelay); 585 rtrsp->rt_delay_jiffies = longdelay; 586 } else { 587 rcu_read_delay(rrsp, rtrsp); 588 } 589 } 590 591 static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp) 592 { 593 srcu_read_unlock(srcu_ctlp, idx); 594 } 595 596 static int torture_srcu_read_lock_held(void) 597 { 598 return srcu_read_lock_held(srcu_ctlp); 599 } 600 601 static unsigned long srcu_torture_completed(void) 602 { 603 return srcu_batches_completed(srcu_ctlp); 604 } 605 606 static void srcu_torture_deferred_free(struct rcu_torture *rp) 607 { 608 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb); 609 } 610 611 static void srcu_torture_synchronize(void) 612 { 613 synchronize_srcu(srcu_ctlp); 614 } 615 616 static unsigned long srcu_torture_get_gp_state(void) 617 { 618 return get_state_synchronize_srcu(srcu_ctlp); 619 } 620 621 static unsigned long srcu_torture_start_gp_poll(void) 622 { 623 return start_poll_synchronize_srcu(srcu_ctlp); 624 } 625 626 static bool srcu_torture_poll_gp_state(unsigned long oldstate) 627 { 628 return poll_state_synchronize_srcu(srcu_ctlp, oldstate); 629 } 630 631 static void srcu_torture_call(struct rcu_head *head, 632 rcu_callback_t func) 633 { 634 call_srcu(srcu_ctlp, head, func); 635 } 636 637 static void srcu_torture_barrier(void) 638 { 639 srcu_barrier(srcu_ctlp); 640 } 641 642 static void srcu_torture_stats(void) 643 { 644 srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG); 645 } 646 647 static void srcu_torture_synchronize_expedited(void) 648 { 649 synchronize_srcu_expedited(srcu_ctlp); 650 } 651 652 static struct rcu_torture_ops srcu_ops = { 653 .ttype = SRCU_FLAVOR, 654 .init = rcu_sync_torture_init, 655 .readlock = srcu_torture_read_lock, 656 .read_delay = srcu_read_delay, 657 .readunlock = srcu_torture_read_unlock, 658 .readlock_held = torture_srcu_read_lock_held, 659 .get_gp_seq = srcu_torture_completed, 660 .deferred_free = srcu_torture_deferred_free, 661 .sync = srcu_torture_synchronize, 662 .exp_sync = srcu_torture_synchronize_expedited, 663 .get_gp_state = srcu_torture_get_gp_state, 664 .start_gp_poll = srcu_torture_start_gp_poll, 665 .poll_gp_state = srcu_torture_poll_gp_state, 666 .call = srcu_torture_call, 667 .cb_barrier = srcu_torture_barrier, 668 .stats = srcu_torture_stats, 669 .irq_capable = 1, 670 .name = "srcu" 671 }; 672 673 static void srcu_torture_init(void) 674 { 675 rcu_sync_torture_init(); 676 WARN_ON(init_srcu_struct(&srcu_ctld)); 677 srcu_ctlp = &srcu_ctld; 678 } 679 680 static void srcu_torture_cleanup(void) 681 { 682 cleanup_srcu_struct(&srcu_ctld); 683 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */ 684 } 685 686 /* As above, but dynamically allocated. */ 687 static struct rcu_torture_ops srcud_ops = { 688 .ttype = SRCU_FLAVOR, 689 .init = srcu_torture_init, 690 .cleanup = srcu_torture_cleanup, 691 .readlock = srcu_torture_read_lock, 692 .read_delay = srcu_read_delay, 693 .readunlock = srcu_torture_read_unlock, 694 .readlock_held = torture_srcu_read_lock_held, 695 .get_gp_seq = srcu_torture_completed, 696 .deferred_free = srcu_torture_deferred_free, 697 .sync = srcu_torture_synchronize, 698 .exp_sync = srcu_torture_synchronize_expedited, 699 .call = srcu_torture_call, 700 .cb_barrier = srcu_torture_barrier, 701 .stats = srcu_torture_stats, 702 .irq_capable = 1, 703 .name = "srcud" 704 }; 705 706 /* As above, but broken due to inappropriate reader extension. */ 707 static struct rcu_torture_ops busted_srcud_ops = { 708 .ttype = SRCU_FLAVOR, 709 .init = srcu_torture_init, 710 .cleanup = srcu_torture_cleanup, 711 .readlock = srcu_torture_read_lock, 712 .read_delay = rcu_read_delay, 713 .readunlock = srcu_torture_read_unlock, 714 .readlock_held = torture_srcu_read_lock_held, 715 .get_gp_seq = srcu_torture_completed, 716 .deferred_free = srcu_torture_deferred_free, 717 .sync = srcu_torture_synchronize, 718 .exp_sync = srcu_torture_synchronize_expedited, 719 .call = srcu_torture_call, 720 .cb_barrier = srcu_torture_barrier, 721 .stats = srcu_torture_stats, 722 .irq_capable = 1, 723 .extendables = RCUTORTURE_MAX_EXTEND, 724 .name = "busted_srcud" 725 }; 726 727 /* 728 * Definitions for RCU-tasks torture testing. 729 */ 730 731 static int tasks_torture_read_lock(void) 732 { 733 return 0; 734 } 735 736 static void tasks_torture_read_unlock(int idx) 737 { 738 } 739 740 static void rcu_tasks_torture_deferred_free(struct rcu_torture *p) 741 { 742 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb); 743 } 744 745 static void synchronize_rcu_mult_test(void) 746 { 747 synchronize_rcu_mult(call_rcu_tasks, call_rcu); 748 } 749 750 static struct rcu_torture_ops tasks_ops = { 751 .ttype = RCU_TASKS_FLAVOR, 752 .init = rcu_sync_torture_init, 753 .readlock = tasks_torture_read_lock, 754 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 755 .readunlock = tasks_torture_read_unlock, 756 .get_gp_seq = rcu_no_completed, 757 .deferred_free = rcu_tasks_torture_deferred_free, 758 .sync = synchronize_rcu_tasks, 759 .exp_sync = synchronize_rcu_mult_test, 760 .call = call_rcu_tasks, 761 .cb_barrier = rcu_barrier_tasks, 762 .gp_kthread_dbg = show_rcu_tasks_classic_gp_kthread, 763 .fqs = NULL, 764 .stats = NULL, 765 .irq_capable = 1, 766 .slow_gps = 1, 767 .name = "tasks" 768 }; 769 770 /* 771 * Definitions for trivial CONFIG_PREEMPT=n-only torture testing. 772 * This implementation does not necessarily work well with CPU hotplug. 773 */ 774 775 static void synchronize_rcu_trivial(void) 776 { 777 int cpu; 778 779 for_each_online_cpu(cpu) { 780 rcutorture_sched_setaffinity(current->pid, cpumask_of(cpu)); 781 WARN_ON_ONCE(raw_smp_processor_id() != cpu); 782 } 783 } 784 785 static int rcu_torture_read_lock_trivial(void) __acquires(RCU) 786 { 787 preempt_disable(); 788 return 0; 789 } 790 791 static void rcu_torture_read_unlock_trivial(int idx) __releases(RCU) 792 { 793 preempt_enable(); 794 } 795 796 static struct rcu_torture_ops trivial_ops = { 797 .ttype = RCU_TRIVIAL_FLAVOR, 798 .init = rcu_sync_torture_init, 799 .readlock = rcu_torture_read_lock_trivial, 800 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 801 .readunlock = rcu_torture_read_unlock_trivial, 802 .readlock_held = torture_readlock_not_held, 803 .get_gp_seq = rcu_no_completed, 804 .sync = synchronize_rcu_trivial, 805 .exp_sync = synchronize_rcu_trivial, 806 .fqs = NULL, 807 .stats = NULL, 808 .irq_capable = 1, 809 .name = "trivial" 810 }; 811 812 /* 813 * Definitions for rude RCU-tasks torture testing. 814 */ 815 816 static void rcu_tasks_rude_torture_deferred_free(struct rcu_torture *p) 817 { 818 call_rcu_tasks_rude(&p->rtort_rcu, rcu_torture_cb); 819 } 820 821 static struct rcu_torture_ops tasks_rude_ops = { 822 .ttype = RCU_TASKS_RUDE_FLAVOR, 823 .init = rcu_sync_torture_init, 824 .readlock = rcu_torture_read_lock_trivial, 825 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 826 .readunlock = rcu_torture_read_unlock_trivial, 827 .get_gp_seq = rcu_no_completed, 828 .deferred_free = rcu_tasks_rude_torture_deferred_free, 829 .sync = synchronize_rcu_tasks_rude, 830 .exp_sync = synchronize_rcu_tasks_rude, 831 .call = call_rcu_tasks_rude, 832 .cb_barrier = rcu_barrier_tasks_rude, 833 .gp_kthread_dbg = show_rcu_tasks_rude_gp_kthread, 834 .fqs = NULL, 835 .stats = NULL, 836 .irq_capable = 1, 837 .name = "tasks-rude" 838 }; 839 840 /* 841 * Definitions for tracing RCU-tasks torture testing. 842 */ 843 844 static int tasks_tracing_torture_read_lock(void) 845 { 846 rcu_read_lock_trace(); 847 return 0; 848 } 849 850 static void tasks_tracing_torture_read_unlock(int idx) 851 { 852 rcu_read_unlock_trace(); 853 } 854 855 static void rcu_tasks_tracing_torture_deferred_free(struct rcu_torture *p) 856 { 857 call_rcu_tasks_trace(&p->rtort_rcu, rcu_torture_cb); 858 } 859 860 static struct rcu_torture_ops tasks_tracing_ops = { 861 .ttype = RCU_TASKS_TRACING_FLAVOR, 862 .init = rcu_sync_torture_init, 863 .readlock = tasks_tracing_torture_read_lock, 864 .read_delay = srcu_read_delay, /* just reuse srcu's version. */ 865 .readunlock = tasks_tracing_torture_read_unlock, 866 .readlock_held = rcu_read_lock_trace_held, 867 .get_gp_seq = rcu_no_completed, 868 .deferred_free = rcu_tasks_tracing_torture_deferred_free, 869 .sync = synchronize_rcu_tasks_trace, 870 .exp_sync = synchronize_rcu_tasks_trace, 871 .call = call_rcu_tasks_trace, 872 .cb_barrier = rcu_barrier_tasks_trace, 873 .gp_kthread_dbg = show_rcu_tasks_trace_gp_kthread, 874 .fqs = NULL, 875 .stats = NULL, 876 .irq_capable = 1, 877 .slow_gps = 1, 878 .name = "tasks-tracing" 879 }; 880 881 static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old) 882 { 883 if (!cur_ops->gp_diff) 884 return new - old; 885 return cur_ops->gp_diff(new, old); 886 } 887 888 /* 889 * RCU torture priority-boost testing. Runs one real-time thread per 890 * CPU for moderate bursts, repeatedly starting grace periods and waiting 891 * for them to complete. If a given grace period takes too long, we assume 892 * that priority inversion has occurred. 893 */ 894 895 static int old_rt_runtime = -1; 896 897 static void rcu_torture_disable_rt_throttle(void) 898 { 899 /* 900 * Disable RT throttling so that rcutorture's boost threads don't get 901 * throttled. Only possible if rcutorture is built-in otherwise the 902 * user should manually do this by setting the sched_rt_period_us and 903 * sched_rt_runtime sysctls. 904 */ 905 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime != -1) 906 return; 907 908 old_rt_runtime = sysctl_sched_rt_runtime; 909 sysctl_sched_rt_runtime = -1; 910 } 911 912 static void rcu_torture_enable_rt_throttle(void) 913 { 914 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime == -1) 915 return; 916 917 sysctl_sched_rt_runtime = old_rt_runtime; 918 old_rt_runtime = -1; 919 } 920 921 static bool rcu_torture_boost_failed(unsigned long gp_state, unsigned long *start) 922 { 923 int cpu; 924 static int dbg_done; 925 unsigned long end = jiffies; 926 bool gp_done; 927 unsigned long j; 928 static unsigned long last_persist; 929 unsigned long lp; 930 unsigned long mininterval = test_boost_duration * HZ - HZ / 2; 931 932 if (end - *start > mininterval) { 933 // Recheck after checking time to avoid false positives. 934 smp_mb(); // Time check before grace-period check. 935 if (cur_ops->poll_gp_state(gp_state)) 936 return false; // passed, though perhaps just barely 937 if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, &cpu)) { 938 // At most one persisted message per boost test. 939 j = jiffies; 940 lp = READ_ONCE(last_persist); 941 if (time_after(j, lp + mininterval) && cmpxchg(&last_persist, lp, j) == lp) 942 pr_info("Boost inversion persisted: No QS from CPU %d\n", cpu); 943 return false; // passed on a technicality 944 } 945 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed"); 946 n_rcu_torture_boost_failure++; 947 if (!xchg(&dbg_done, 1) && cur_ops->gp_kthread_dbg) { 948 pr_info("Boost inversion thread ->rt_priority %u gp_state %lu jiffies %lu\n", 949 current->rt_priority, gp_state, end - *start); 950 cur_ops->gp_kthread_dbg(); 951 // Recheck after print to flag grace period ending during splat. 952 gp_done = cur_ops->poll_gp_state(gp_state); 953 pr_info("Boost inversion: GP %lu %s.\n", gp_state, 954 gp_done ? "ended already" : "still pending"); 955 956 } 957 958 return true; // failed 959 } else if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, NULL)) { 960 *start = jiffies; 961 } 962 963 return false; // passed 964 } 965 966 static int rcu_torture_boost(void *arg) 967 { 968 unsigned long endtime; 969 unsigned long gp_state; 970 unsigned long gp_state_time; 971 unsigned long oldstarttime; 972 973 VERBOSE_TOROUT_STRING("rcu_torture_boost started"); 974 975 /* Set real-time priority. */ 976 sched_set_fifo_low(current); 977 978 /* Each pass through the following loop does one boost-test cycle. */ 979 do { 980 bool failed = false; // Test failed already in this test interval 981 bool gp_initiated = false; 982 983 if (kthread_should_stop()) 984 goto checkwait; 985 986 /* Wait for the next test interval. */ 987 oldstarttime = boost_starttime; 988 while (time_before(jiffies, oldstarttime)) { 989 schedule_timeout_interruptible(oldstarttime - jiffies); 990 if (stutter_wait("rcu_torture_boost")) 991 sched_set_fifo_low(current); 992 if (torture_must_stop()) 993 goto checkwait; 994 } 995 996 // Do one boost-test interval. 997 endtime = oldstarttime + test_boost_duration * HZ; 998 while (time_before(jiffies, endtime)) { 999 // Has current GP gone too long? 1000 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state)) 1001 failed = rcu_torture_boost_failed(gp_state, &gp_state_time); 1002 // If we don't have a grace period in flight, start one. 1003 if (!gp_initiated || cur_ops->poll_gp_state(gp_state)) { 1004 gp_state = cur_ops->start_gp_poll(); 1005 gp_initiated = true; 1006 gp_state_time = jiffies; 1007 } 1008 if (stutter_wait("rcu_torture_boost")) { 1009 sched_set_fifo_low(current); 1010 // If the grace period already ended, 1011 // we don't know when that happened, so 1012 // start over. 1013 if (cur_ops->poll_gp_state(gp_state)) 1014 gp_initiated = false; 1015 } 1016 if (torture_must_stop()) 1017 goto checkwait; 1018 } 1019 1020 // In case the grace period extended beyond the end of the loop. 1021 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state)) 1022 rcu_torture_boost_failed(gp_state, &gp_state_time); 1023 1024 /* 1025 * Set the start time of the next test interval. 1026 * Yes, this is vulnerable to long delays, but such 1027 * delays simply cause a false negative for the next 1028 * interval. Besides, we are running at RT priority, 1029 * so delays should be relatively rare. 1030 */ 1031 while (oldstarttime == boost_starttime && !kthread_should_stop()) { 1032 if (mutex_trylock(&boost_mutex)) { 1033 if (oldstarttime == boost_starttime) { 1034 boost_starttime = jiffies + test_boost_interval * HZ; 1035 n_rcu_torture_boosts++; 1036 } 1037 mutex_unlock(&boost_mutex); 1038 break; 1039 } 1040 schedule_timeout_uninterruptible(1); 1041 } 1042 1043 /* Go do the stutter. */ 1044 checkwait: if (stutter_wait("rcu_torture_boost")) 1045 sched_set_fifo_low(current); 1046 } while (!torture_must_stop()); 1047 1048 /* Clean up and exit. */ 1049 while (!kthread_should_stop()) { 1050 torture_shutdown_absorb("rcu_torture_boost"); 1051 schedule_timeout_uninterruptible(1); 1052 } 1053 torture_kthread_stopping("rcu_torture_boost"); 1054 return 0; 1055 } 1056 1057 /* 1058 * RCU torture force-quiescent-state kthread. Repeatedly induces 1059 * bursts of calls to force_quiescent_state(), increasing the probability 1060 * of occurrence of some important types of race conditions. 1061 */ 1062 static int 1063 rcu_torture_fqs(void *arg) 1064 { 1065 unsigned long fqs_resume_time; 1066 int fqs_burst_remaining; 1067 int oldnice = task_nice(current); 1068 1069 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started"); 1070 do { 1071 fqs_resume_time = jiffies + fqs_stutter * HZ; 1072 while (time_before(jiffies, fqs_resume_time) && 1073 !kthread_should_stop()) { 1074 schedule_timeout_interruptible(1); 1075 } 1076 fqs_burst_remaining = fqs_duration; 1077 while (fqs_burst_remaining > 0 && 1078 !kthread_should_stop()) { 1079 cur_ops->fqs(); 1080 udelay(fqs_holdoff); 1081 fqs_burst_remaining -= fqs_holdoff; 1082 } 1083 if (stutter_wait("rcu_torture_fqs")) 1084 sched_set_normal(current, oldnice); 1085 } while (!torture_must_stop()); 1086 torture_kthread_stopping("rcu_torture_fqs"); 1087 return 0; 1088 } 1089 1090 // Used by writers to randomly choose from the available grace-period 1091 // primitives. The only purpose of the initialization is to size the array. 1092 static int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC, RTWS_COND_GET, RTWS_POLL_GET, RTWS_SYNC }; 1093 static int nsynctypes; 1094 1095 /* 1096 * Determine which grace-period primitives are available. 1097 */ 1098 static void rcu_torture_write_types(void) 1099 { 1100 bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal; 1101 bool gp_poll1 = gp_poll, gp_sync1 = gp_sync; 1102 1103 /* Initialize synctype[] array. If none set, take default. */ 1104 if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_poll1 && !gp_sync1) 1105 gp_cond1 = gp_exp1 = gp_normal1 = gp_poll1 = gp_sync1 = true; 1106 if (gp_cond1 && cur_ops->get_gp_state && cur_ops->cond_sync) { 1107 synctype[nsynctypes++] = RTWS_COND_GET; 1108 pr_info("%s: Testing conditional GPs.\n", __func__); 1109 } else if (gp_cond && (!cur_ops->get_gp_state || !cur_ops->cond_sync)) { 1110 pr_alert("%s: gp_cond without primitives.\n", __func__); 1111 } 1112 if (gp_exp1 && cur_ops->exp_sync) { 1113 synctype[nsynctypes++] = RTWS_EXP_SYNC; 1114 pr_info("%s: Testing expedited GPs.\n", __func__); 1115 } else if (gp_exp && !cur_ops->exp_sync) { 1116 pr_alert("%s: gp_exp without primitives.\n", __func__); 1117 } 1118 if (gp_normal1 && cur_ops->deferred_free) { 1119 synctype[nsynctypes++] = RTWS_DEF_FREE; 1120 pr_info("%s: Testing asynchronous GPs.\n", __func__); 1121 } else if (gp_normal && !cur_ops->deferred_free) { 1122 pr_alert("%s: gp_normal without primitives.\n", __func__); 1123 } 1124 if (gp_poll1 && cur_ops->start_gp_poll && cur_ops->poll_gp_state) { 1125 synctype[nsynctypes++] = RTWS_POLL_GET; 1126 pr_info("%s: Testing polling GPs.\n", __func__); 1127 } else if (gp_poll && (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)) { 1128 pr_alert("%s: gp_poll without primitives.\n", __func__); 1129 } 1130 if (gp_sync1 && cur_ops->sync) { 1131 synctype[nsynctypes++] = RTWS_SYNC; 1132 pr_info("%s: Testing normal GPs.\n", __func__); 1133 } else if (gp_sync && !cur_ops->sync) { 1134 pr_alert("%s: gp_sync without primitives.\n", __func__); 1135 } 1136 } 1137 1138 /* 1139 * RCU torture writer kthread. Repeatedly substitutes a new structure 1140 * for that pointed to by rcu_torture_current, freeing the old structure 1141 * after a series of grace periods (the "pipeline"). 1142 */ 1143 static int 1144 rcu_torture_writer(void *arg) 1145 { 1146 bool boot_ended; 1147 bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal(); 1148 unsigned long cookie; 1149 int expediting = 0; 1150 unsigned long gp_snap; 1151 int i; 1152 int idx; 1153 int oldnice = task_nice(current); 1154 struct rcu_torture *rp; 1155 struct rcu_torture *old_rp; 1156 static DEFINE_TORTURE_RANDOM(rand); 1157 bool stutter_waited; 1158 1159 VERBOSE_TOROUT_STRING("rcu_torture_writer task started"); 1160 if (!can_expedite) 1161 pr_alert("%s" TORTURE_FLAG 1162 " GP expediting controlled from boot/sysfs for %s.\n", 1163 torture_type, cur_ops->name); 1164 if (WARN_ONCE(nsynctypes == 0, 1165 "rcu_torture_writer: No update-side primitives.\n")) { 1166 /* 1167 * No updates primitives, so don't try updating. 1168 * The resulting test won't be testing much, hence the 1169 * above WARN_ONCE(). 1170 */ 1171 rcu_torture_writer_state = RTWS_STOPPING; 1172 torture_kthread_stopping("rcu_torture_writer"); 1173 } 1174 1175 do { 1176 rcu_torture_writer_state = RTWS_FIXED_DELAY; 1177 torture_hrtimeout_us(500, 1000, &rand); 1178 rp = rcu_torture_alloc(); 1179 if (rp == NULL) 1180 continue; 1181 rp->rtort_pipe_count = 0; 1182 rcu_torture_writer_state = RTWS_DELAY; 1183 udelay(torture_random(&rand) & 0x3ff); 1184 rcu_torture_writer_state = RTWS_REPLACE; 1185 old_rp = rcu_dereference_check(rcu_torture_current, 1186 current == writer_task); 1187 rp->rtort_mbtest = 1; 1188 rcu_assign_pointer(rcu_torture_current, rp); 1189 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */ 1190 if (old_rp) { 1191 i = old_rp->rtort_pipe_count; 1192 if (i > RCU_TORTURE_PIPE_LEN) 1193 i = RCU_TORTURE_PIPE_LEN; 1194 atomic_inc(&rcu_torture_wcount[i]); 1195 WRITE_ONCE(old_rp->rtort_pipe_count, 1196 old_rp->rtort_pipe_count + 1); 1197 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) { 1198 idx = cur_ops->readlock(); 1199 cookie = cur_ops->get_gp_state(); 1200 WARN_ONCE(rcu_torture_writer_state != RTWS_DEF_FREE && 1201 cur_ops->poll_gp_state(cookie), 1202 "%s: Cookie check 1 failed %s(%d) %lu->%lu\n", 1203 __func__, 1204 rcu_torture_writer_state_getname(), 1205 rcu_torture_writer_state, 1206 cookie, cur_ops->get_gp_state()); 1207 cur_ops->readunlock(idx); 1208 } 1209 switch (synctype[torture_random(&rand) % nsynctypes]) { 1210 case RTWS_DEF_FREE: 1211 rcu_torture_writer_state = RTWS_DEF_FREE; 1212 cur_ops->deferred_free(old_rp); 1213 break; 1214 case RTWS_EXP_SYNC: 1215 rcu_torture_writer_state = RTWS_EXP_SYNC; 1216 cur_ops->exp_sync(); 1217 rcu_torture_pipe_update(old_rp); 1218 break; 1219 case RTWS_COND_GET: 1220 rcu_torture_writer_state = RTWS_COND_GET; 1221 gp_snap = cur_ops->get_gp_state(); 1222 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); 1223 rcu_torture_writer_state = RTWS_COND_SYNC; 1224 cur_ops->cond_sync(gp_snap); 1225 rcu_torture_pipe_update(old_rp); 1226 break; 1227 case RTWS_POLL_GET: 1228 rcu_torture_writer_state = RTWS_POLL_GET; 1229 gp_snap = cur_ops->start_gp_poll(); 1230 rcu_torture_writer_state = RTWS_POLL_WAIT; 1231 while (!cur_ops->poll_gp_state(gp_snap)) 1232 torture_hrtimeout_jiffies(torture_random(&rand) % 16, 1233 &rand); 1234 rcu_torture_pipe_update(old_rp); 1235 break; 1236 case RTWS_SYNC: 1237 rcu_torture_writer_state = RTWS_SYNC; 1238 cur_ops->sync(); 1239 rcu_torture_pipe_update(old_rp); 1240 break; 1241 default: 1242 WARN_ON_ONCE(1); 1243 break; 1244 } 1245 } 1246 WRITE_ONCE(rcu_torture_current_version, 1247 rcu_torture_current_version + 1); 1248 /* Cycle through nesting levels of rcu_expedite_gp() calls. */ 1249 if (can_expedite && 1250 !(torture_random(&rand) & 0xff & (!!expediting - 1))) { 1251 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited()); 1252 if (expediting >= 0) 1253 rcu_expedite_gp(); 1254 else 1255 rcu_unexpedite_gp(); 1256 if (++expediting > 3) 1257 expediting = -expediting; 1258 } else if (!can_expedite) { /* Disabled during boot, recheck. */ 1259 can_expedite = !rcu_gp_is_expedited() && 1260 !rcu_gp_is_normal(); 1261 } 1262 rcu_torture_writer_state = RTWS_STUTTER; 1263 boot_ended = rcu_inkernel_boot_has_ended(); 1264 stutter_waited = stutter_wait("rcu_torture_writer"); 1265 if (stutter_waited && 1266 !READ_ONCE(rcu_fwd_cb_nodelay) && 1267 !cur_ops->slow_gps && 1268 !torture_must_stop() && 1269 boot_ended) 1270 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) 1271 if (list_empty(&rcu_tortures[i].rtort_free) && 1272 rcu_access_pointer(rcu_torture_current) != 1273 &rcu_tortures[i]) { 1274 rcu_ftrace_dump(DUMP_ALL); 1275 WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count); 1276 } 1277 if (stutter_waited) 1278 sched_set_normal(current, oldnice); 1279 } while (!torture_must_stop()); 1280 rcu_torture_current = NULL; // Let stats task know that we are done. 1281 /* Reset expediting back to unexpedited. */ 1282 if (expediting > 0) 1283 expediting = -expediting; 1284 while (can_expedite && expediting++ < 0) 1285 rcu_unexpedite_gp(); 1286 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited()); 1287 if (!can_expedite) 1288 pr_alert("%s" TORTURE_FLAG 1289 " Dynamic grace-period expediting was disabled.\n", 1290 torture_type); 1291 rcu_torture_writer_state = RTWS_STOPPING; 1292 torture_kthread_stopping("rcu_torture_writer"); 1293 return 0; 1294 } 1295 1296 /* 1297 * RCU torture fake writer kthread. Repeatedly calls sync, with a random 1298 * delay between calls. 1299 */ 1300 static int 1301 rcu_torture_fakewriter(void *arg) 1302 { 1303 unsigned long gp_snap; 1304 DEFINE_TORTURE_RANDOM(rand); 1305 1306 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started"); 1307 set_user_nice(current, MAX_NICE); 1308 1309 do { 1310 torture_hrtimeout_jiffies(torture_random(&rand) % 10, &rand); 1311 if (cur_ops->cb_barrier != NULL && 1312 torture_random(&rand) % (nfakewriters * 8) == 0) { 1313 cur_ops->cb_barrier(); 1314 } else { 1315 switch (synctype[torture_random(&rand) % nsynctypes]) { 1316 case RTWS_DEF_FREE: 1317 break; 1318 case RTWS_EXP_SYNC: 1319 cur_ops->exp_sync(); 1320 break; 1321 case RTWS_COND_GET: 1322 gp_snap = cur_ops->get_gp_state(); 1323 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); 1324 cur_ops->cond_sync(gp_snap); 1325 break; 1326 case RTWS_POLL_GET: 1327 gp_snap = cur_ops->start_gp_poll(); 1328 while (!cur_ops->poll_gp_state(gp_snap)) { 1329 torture_hrtimeout_jiffies(torture_random(&rand) % 16, 1330 &rand); 1331 } 1332 break; 1333 case RTWS_SYNC: 1334 cur_ops->sync(); 1335 break; 1336 default: 1337 WARN_ON_ONCE(1); 1338 break; 1339 } 1340 } 1341 stutter_wait("rcu_torture_fakewriter"); 1342 } while (!torture_must_stop()); 1343 1344 torture_kthread_stopping("rcu_torture_fakewriter"); 1345 return 0; 1346 } 1347 1348 static void rcu_torture_timer_cb(struct rcu_head *rhp) 1349 { 1350 kfree(rhp); 1351 } 1352 1353 // Set up and carry out testing of RCU's global memory ordering 1354 static void rcu_torture_reader_do_mbchk(long myid, struct rcu_torture *rtp, 1355 struct torture_random_state *trsp) 1356 { 1357 unsigned long loops; 1358 int noc = torture_num_online_cpus(); 1359 int rdrchked; 1360 int rdrchker; 1361 struct rcu_torture_reader_check *rtrcp; // Me. 1362 struct rcu_torture_reader_check *rtrcp_assigner; // Assigned us to do checking. 1363 struct rcu_torture_reader_check *rtrcp_chked; // Reader being checked. 1364 struct rcu_torture_reader_check *rtrcp_chker; // Reader doing checking when not me. 1365 1366 if (myid < 0) 1367 return; // Don't try this from timer handlers. 1368 1369 // Increment my counter. 1370 rtrcp = &rcu_torture_reader_mbchk[myid]; 1371 WRITE_ONCE(rtrcp->rtc_myloops, rtrcp->rtc_myloops + 1); 1372 1373 // Attempt to assign someone else some checking work. 1374 rdrchked = torture_random(trsp) % nrealreaders; 1375 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked]; 1376 rdrchker = torture_random(trsp) % nrealreaders; 1377 rtrcp_chker = &rcu_torture_reader_mbchk[rdrchker]; 1378 if (rdrchked != myid && rdrchked != rdrchker && noc >= rdrchked && noc >= rdrchker && 1379 smp_load_acquire(&rtrcp->rtc_chkrdr) < 0 && // Pairs with smp_store_release below. 1380 !READ_ONCE(rtp->rtort_chkp) && 1381 !smp_load_acquire(&rtrcp_chker->rtc_assigner)) { // Pairs with smp_store_release below. 1382 rtrcp->rtc_chkloops = READ_ONCE(rtrcp_chked->rtc_myloops); 1383 WARN_ON_ONCE(rtrcp->rtc_chkrdr >= 0); 1384 rtrcp->rtc_chkrdr = rdrchked; 1385 WARN_ON_ONCE(rtrcp->rtc_ready); // This gets set after the grace period ends. 1386 if (cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, NULL, rtrcp) || 1387 cmpxchg_relaxed(&rtp->rtort_chkp, NULL, rtrcp)) 1388 (void)cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, rtrcp, NULL); // Back out. 1389 } 1390 1391 // If assigned some completed work, do it! 1392 rtrcp_assigner = READ_ONCE(rtrcp->rtc_assigner); 1393 if (!rtrcp_assigner || !smp_load_acquire(&rtrcp_assigner->rtc_ready)) 1394 return; // No work or work not yet ready. 1395 rdrchked = rtrcp_assigner->rtc_chkrdr; 1396 if (WARN_ON_ONCE(rdrchked < 0)) 1397 return; 1398 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked]; 1399 loops = READ_ONCE(rtrcp_chked->rtc_myloops); 1400 atomic_inc(&n_rcu_torture_mbchk_tries); 1401 if (ULONG_CMP_LT(loops, rtrcp_assigner->rtc_chkloops)) 1402 atomic_inc(&n_rcu_torture_mbchk_fail); 1403 rtrcp_assigner->rtc_chkloops = loops + ULONG_MAX / 2; 1404 rtrcp_assigner->rtc_ready = 0; 1405 smp_store_release(&rtrcp->rtc_assigner, NULL); // Someone else can assign us work. 1406 smp_store_release(&rtrcp_assigner->rtc_chkrdr, -1); // Assigner can again assign. 1407 } 1408 1409 /* 1410 * Do one extension of an RCU read-side critical section using the 1411 * current reader state in readstate (set to zero for initial entry 1412 * to extended critical section), set the new state as specified by 1413 * newstate (set to zero for final exit from extended critical section), 1414 * and random-number-generator state in trsp. If this is neither the 1415 * beginning or end of the critical section and if there was actually a 1416 * change, do a ->read_delay(). 1417 */ 1418 static void rcutorture_one_extend(int *readstate, int newstate, 1419 struct torture_random_state *trsp, 1420 struct rt_read_seg *rtrsp) 1421 { 1422 unsigned long flags; 1423 int idxnew = -1; 1424 int idxold = *readstate; 1425 int statesnew = ~*readstate & newstate; 1426 int statesold = *readstate & ~newstate; 1427 1428 WARN_ON_ONCE(idxold < 0); 1429 WARN_ON_ONCE((idxold >> RCUTORTURE_RDR_SHIFT) > 1); 1430 rtrsp->rt_readstate = newstate; 1431 1432 /* First, put new protection in place to avoid critical-section gap. */ 1433 if (statesnew & RCUTORTURE_RDR_BH) 1434 local_bh_disable(); 1435 if (statesnew & RCUTORTURE_RDR_IRQ) 1436 local_irq_disable(); 1437 if (statesnew & RCUTORTURE_RDR_PREEMPT) 1438 preempt_disable(); 1439 if (statesnew & RCUTORTURE_RDR_RBH) 1440 rcu_read_lock_bh(); 1441 if (statesnew & RCUTORTURE_RDR_SCHED) 1442 rcu_read_lock_sched(); 1443 if (statesnew & RCUTORTURE_RDR_RCU) 1444 idxnew = cur_ops->readlock() << RCUTORTURE_RDR_SHIFT; 1445 1446 /* Next, remove old protection, irq first due to bh conflict. */ 1447 if (statesold & RCUTORTURE_RDR_IRQ) 1448 local_irq_enable(); 1449 if (statesold & RCUTORTURE_RDR_BH) 1450 local_bh_enable(); 1451 if (statesold & RCUTORTURE_RDR_PREEMPT) 1452 preempt_enable(); 1453 if (statesold & RCUTORTURE_RDR_RBH) 1454 rcu_read_unlock_bh(); 1455 if (statesold & RCUTORTURE_RDR_SCHED) 1456 rcu_read_unlock_sched(); 1457 if (statesold & RCUTORTURE_RDR_RCU) { 1458 bool lockit = !statesnew && !(torture_random(trsp) & 0xffff); 1459 1460 if (lockit) 1461 raw_spin_lock_irqsave(¤t->pi_lock, flags); 1462 cur_ops->readunlock(idxold >> RCUTORTURE_RDR_SHIFT); 1463 if (lockit) 1464 raw_spin_unlock_irqrestore(¤t->pi_lock, flags); 1465 } 1466 1467 /* Delay if neither beginning nor end and there was a change. */ 1468 if ((statesnew || statesold) && *readstate && newstate) 1469 cur_ops->read_delay(trsp, rtrsp); 1470 1471 /* Update the reader state. */ 1472 if (idxnew == -1) 1473 idxnew = idxold & ~RCUTORTURE_RDR_MASK; 1474 WARN_ON_ONCE(idxnew < 0); 1475 WARN_ON_ONCE((idxnew >> RCUTORTURE_RDR_SHIFT) > 1); 1476 *readstate = idxnew | newstate; 1477 WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT) < 0); 1478 WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT) > 1); 1479 } 1480 1481 /* Return the biggest extendables mask given current RCU and boot parameters. */ 1482 static int rcutorture_extend_mask_max(void) 1483 { 1484 int mask; 1485 1486 WARN_ON_ONCE(extendables & ~RCUTORTURE_MAX_EXTEND); 1487 mask = extendables & RCUTORTURE_MAX_EXTEND & cur_ops->extendables; 1488 mask = mask | RCUTORTURE_RDR_RCU; 1489 return mask; 1490 } 1491 1492 /* Return a random protection state mask, but with at least one bit set. */ 1493 static int 1494 rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp) 1495 { 1496 int mask = rcutorture_extend_mask_max(); 1497 unsigned long randmask1 = torture_random(trsp) >> 8; 1498 unsigned long randmask2 = randmask1 >> 3; 1499 1500 WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT); 1501 /* Mostly only one bit (need preemption!), sometimes lots of bits. */ 1502 if (!(randmask1 & 0x7)) 1503 mask = mask & randmask2; 1504 else 1505 mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS)); 1506 /* Can't enable bh w/irq disabled. */ 1507 if ((mask & RCUTORTURE_RDR_IRQ) && 1508 ((!(mask & RCUTORTURE_RDR_BH) && (oldmask & RCUTORTURE_RDR_BH)) || 1509 (!(mask & RCUTORTURE_RDR_RBH) && (oldmask & RCUTORTURE_RDR_RBH)))) 1510 mask |= RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH; 1511 return mask ?: RCUTORTURE_RDR_RCU; 1512 } 1513 1514 /* 1515 * Do a randomly selected number of extensions of an existing RCU read-side 1516 * critical section. 1517 */ 1518 static struct rt_read_seg * 1519 rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp, 1520 struct rt_read_seg *rtrsp) 1521 { 1522 int i; 1523 int j; 1524 int mask = rcutorture_extend_mask_max(); 1525 1526 WARN_ON_ONCE(!*readstate); /* -Existing- RCU read-side critsect! */ 1527 if (!((mask - 1) & mask)) 1528 return rtrsp; /* Current RCU reader not extendable. */ 1529 /* Bias towards larger numbers of loops. */ 1530 i = (torture_random(trsp) >> 3); 1531 i = ((i | (i >> 3)) & RCUTORTURE_RDR_MAX_LOOPS) + 1; 1532 for (j = 0; j < i; j++) { 1533 mask = rcutorture_extend_mask(*readstate, trsp); 1534 rcutorture_one_extend(readstate, mask, trsp, &rtrsp[j]); 1535 } 1536 return &rtrsp[j]; 1537 } 1538 1539 /* 1540 * Do one read-side critical section, returning false if there was 1541 * no data to read. Can be invoked both from process context and 1542 * from a timer handler. 1543 */ 1544 static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid) 1545 { 1546 unsigned long cookie; 1547 int i; 1548 unsigned long started; 1549 unsigned long completed; 1550 int newstate; 1551 struct rcu_torture *p; 1552 int pipe_count; 1553 int readstate = 0; 1554 struct rt_read_seg rtseg[RCUTORTURE_RDR_MAX_SEGS] = { { 0 } }; 1555 struct rt_read_seg *rtrsp = &rtseg[0]; 1556 struct rt_read_seg *rtrsp1; 1557 unsigned long long ts; 1558 1559 WARN_ON_ONCE(!rcu_is_watching()); 1560 newstate = rcutorture_extend_mask(readstate, trsp); 1561 rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++); 1562 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) 1563 cookie = cur_ops->get_gp_state(); 1564 started = cur_ops->get_gp_seq(); 1565 ts = rcu_trace_clock_local(); 1566 p = rcu_dereference_check(rcu_torture_current, 1567 !cur_ops->readlock_held || cur_ops->readlock_held()); 1568 if (p == NULL) { 1569 /* Wait for rcu_torture_writer to get underway */ 1570 rcutorture_one_extend(&readstate, 0, trsp, rtrsp); 1571 return false; 1572 } 1573 if (p->rtort_mbtest == 0) 1574 atomic_inc(&n_rcu_torture_mberror); 1575 rcu_torture_reader_do_mbchk(myid, p, trsp); 1576 rtrsp = rcutorture_loop_extend(&readstate, trsp, rtrsp); 1577 preempt_disable(); 1578 pipe_count = READ_ONCE(p->rtort_pipe_count); 1579 if (pipe_count > RCU_TORTURE_PIPE_LEN) { 1580 /* Should not happen, but... */ 1581 pipe_count = RCU_TORTURE_PIPE_LEN; 1582 } 1583 completed = cur_ops->get_gp_seq(); 1584 if (pipe_count > 1) { 1585 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, 1586 ts, started, completed); 1587 rcu_ftrace_dump(DUMP_ALL); 1588 } 1589 __this_cpu_inc(rcu_torture_count[pipe_count]); 1590 completed = rcutorture_seq_diff(completed, started); 1591 if (completed > RCU_TORTURE_PIPE_LEN) { 1592 /* Should not happen, but... */ 1593 completed = RCU_TORTURE_PIPE_LEN; 1594 } 1595 __this_cpu_inc(rcu_torture_batch[completed]); 1596 preempt_enable(); 1597 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) 1598 WARN_ONCE(cur_ops->poll_gp_state(cookie), 1599 "%s: Cookie check 2 failed %s(%d) %lu->%lu\n", 1600 __func__, 1601 rcu_torture_writer_state_getname(), 1602 rcu_torture_writer_state, 1603 cookie, cur_ops->get_gp_state()); 1604 rcutorture_one_extend(&readstate, 0, trsp, rtrsp); 1605 WARN_ON_ONCE(readstate & RCUTORTURE_RDR_MASK); 1606 // This next splat is expected behavior if leakpointer, especially 1607 // for CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels. 1608 WARN_ON_ONCE(leakpointer && READ_ONCE(p->rtort_pipe_count) > 1); 1609 1610 /* If error or close call, record the sequence of reader protections. */ 1611 if ((pipe_count > 1 || completed > 1) && !xchg(&err_segs_recorded, 1)) { 1612 i = 0; 1613 for (rtrsp1 = &rtseg[0]; rtrsp1 < rtrsp; rtrsp1++) 1614 err_segs[i++] = *rtrsp1; 1615 rt_read_nsegs = i; 1616 } 1617 1618 return true; 1619 } 1620 1621 static DEFINE_TORTURE_RANDOM_PERCPU(rcu_torture_timer_rand); 1622 1623 /* 1624 * RCU torture reader from timer handler. Dereferences rcu_torture_current, 1625 * incrementing the corresponding element of the pipeline array. The 1626 * counter in the element should never be greater than 1, otherwise, the 1627 * RCU implementation is broken. 1628 */ 1629 static void rcu_torture_timer(struct timer_list *unused) 1630 { 1631 atomic_long_inc(&n_rcu_torture_timers); 1632 (void)rcu_torture_one_read(this_cpu_ptr(&rcu_torture_timer_rand), -1); 1633 1634 /* Test call_rcu() invocation from interrupt handler. */ 1635 if (cur_ops->call) { 1636 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT); 1637 1638 if (rhp) 1639 cur_ops->call(rhp, rcu_torture_timer_cb); 1640 } 1641 } 1642 1643 /* 1644 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current, 1645 * incrementing the corresponding element of the pipeline array. The 1646 * counter in the element should never be greater than 1, otherwise, the 1647 * RCU implementation is broken. 1648 */ 1649 static int 1650 rcu_torture_reader(void *arg) 1651 { 1652 unsigned long lastsleep = jiffies; 1653 long myid = (long)arg; 1654 int mynumonline = myid; 1655 DEFINE_TORTURE_RANDOM(rand); 1656 struct timer_list t; 1657 1658 VERBOSE_TOROUT_STRING("rcu_torture_reader task started"); 1659 set_user_nice(current, MAX_NICE); 1660 if (irqreader && cur_ops->irq_capable) 1661 timer_setup_on_stack(&t, rcu_torture_timer, 0); 1662 tick_dep_set_task(current, TICK_DEP_BIT_RCU); 1663 do { 1664 if (irqreader && cur_ops->irq_capable) { 1665 if (!timer_pending(&t)) 1666 mod_timer(&t, jiffies + 1); 1667 } 1668 if (!rcu_torture_one_read(&rand, myid) && !torture_must_stop()) 1669 schedule_timeout_interruptible(HZ); 1670 if (time_after(jiffies, lastsleep) && !torture_must_stop()) { 1671 torture_hrtimeout_us(500, 1000, &rand); 1672 lastsleep = jiffies + 10; 1673 } 1674 while (torture_num_online_cpus() < mynumonline && !torture_must_stop()) 1675 schedule_timeout_interruptible(HZ / 5); 1676 stutter_wait("rcu_torture_reader"); 1677 } while (!torture_must_stop()); 1678 if (irqreader && cur_ops->irq_capable) { 1679 del_timer_sync(&t); 1680 destroy_timer_on_stack(&t); 1681 } 1682 tick_dep_clear_task(current, TICK_DEP_BIT_RCU); 1683 torture_kthread_stopping("rcu_torture_reader"); 1684 return 0; 1685 } 1686 1687 /* 1688 * Randomly Toggle CPUs' callback-offload state. This uses hrtimers to 1689 * increase race probabilities and fuzzes the interval between toggling. 1690 */ 1691 static int rcu_nocb_toggle(void *arg) 1692 { 1693 int cpu; 1694 int maxcpu = -1; 1695 int oldnice = task_nice(current); 1696 long r; 1697 DEFINE_TORTURE_RANDOM(rand); 1698 ktime_t toggle_delay; 1699 unsigned long toggle_fuzz; 1700 ktime_t toggle_interval = ms_to_ktime(nocbs_toggle); 1701 1702 VERBOSE_TOROUT_STRING("rcu_nocb_toggle task started"); 1703 while (!rcu_inkernel_boot_has_ended()) 1704 schedule_timeout_interruptible(HZ / 10); 1705 for_each_online_cpu(cpu) 1706 maxcpu = cpu; 1707 WARN_ON(maxcpu < 0); 1708 if (toggle_interval > ULONG_MAX) 1709 toggle_fuzz = ULONG_MAX >> 3; 1710 else 1711 toggle_fuzz = toggle_interval >> 3; 1712 if (toggle_fuzz <= 0) 1713 toggle_fuzz = NSEC_PER_USEC; 1714 do { 1715 r = torture_random(&rand); 1716 cpu = (r >> 4) % (maxcpu + 1); 1717 if (r & 0x1) { 1718 rcu_nocb_cpu_offload(cpu); 1719 atomic_long_inc(&n_nocb_offload); 1720 } else { 1721 rcu_nocb_cpu_deoffload(cpu); 1722 atomic_long_inc(&n_nocb_deoffload); 1723 } 1724 toggle_delay = torture_random(&rand) % toggle_fuzz + toggle_interval; 1725 set_current_state(TASK_INTERRUPTIBLE); 1726 schedule_hrtimeout(&toggle_delay, HRTIMER_MODE_REL); 1727 if (stutter_wait("rcu_nocb_toggle")) 1728 sched_set_normal(current, oldnice); 1729 } while (!torture_must_stop()); 1730 torture_kthread_stopping("rcu_nocb_toggle"); 1731 return 0; 1732 } 1733 1734 /* 1735 * Print torture statistics. Caller must ensure that there is only 1736 * one call to this function at a given time!!! This is normally 1737 * accomplished by relying on the module system to only have one copy 1738 * of the module loaded, and then by giving the rcu_torture_stats 1739 * kthread full control (or the init/cleanup functions when rcu_torture_stats 1740 * thread is not running). 1741 */ 1742 static void 1743 rcu_torture_stats_print(void) 1744 { 1745 int cpu; 1746 int i; 1747 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; 1748 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; 1749 struct rcu_torture *rtcp; 1750 static unsigned long rtcv_snap = ULONG_MAX; 1751 static bool splatted; 1752 struct task_struct *wtp; 1753 1754 for_each_possible_cpu(cpu) { 1755 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 1756 pipesummary[i] += READ_ONCE(per_cpu(rcu_torture_count, cpu)[i]); 1757 batchsummary[i] += READ_ONCE(per_cpu(rcu_torture_batch, cpu)[i]); 1758 } 1759 } 1760 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) { 1761 if (pipesummary[i] != 0) 1762 break; 1763 } 1764 1765 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1766 rtcp = rcu_access_pointer(rcu_torture_current); 1767 pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ", 1768 rtcp, 1769 rtcp && !rcu_stall_is_suppressed_at_boot() ? "ver" : "VER", 1770 rcu_torture_current_version, 1771 list_empty(&rcu_torture_freelist), 1772 atomic_read(&n_rcu_torture_alloc), 1773 atomic_read(&n_rcu_torture_alloc_fail), 1774 atomic_read(&n_rcu_torture_free)); 1775 pr_cont("rtmbe: %d rtmbkf: %d/%d rtbe: %ld rtbke: %ld rtbre: %ld ", 1776 atomic_read(&n_rcu_torture_mberror), 1777 atomic_read(&n_rcu_torture_mbchk_fail), atomic_read(&n_rcu_torture_mbchk_tries), 1778 n_rcu_torture_barrier_error, 1779 n_rcu_torture_boost_ktrerror, 1780 n_rcu_torture_boost_rterror); 1781 pr_cont("rtbf: %ld rtb: %ld nt: %ld ", 1782 n_rcu_torture_boost_failure, 1783 n_rcu_torture_boosts, 1784 atomic_long_read(&n_rcu_torture_timers)); 1785 torture_onoff_stats(); 1786 pr_cont("barrier: %ld/%ld:%ld ", 1787 data_race(n_barrier_successes), 1788 data_race(n_barrier_attempts), 1789 data_race(n_rcu_torture_barrier_error)); 1790 pr_cont("read-exits: %ld ", data_race(n_read_exits)); // Statistic. 1791 pr_cont("nocb-toggles: %ld:%ld\n", 1792 atomic_long_read(&n_nocb_offload), atomic_long_read(&n_nocb_deoffload)); 1793 1794 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1795 if (atomic_read(&n_rcu_torture_mberror) || 1796 atomic_read(&n_rcu_torture_mbchk_fail) || 1797 n_rcu_torture_barrier_error || n_rcu_torture_boost_ktrerror || 1798 n_rcu_torture_boost_rterror || n_rcu_torture_boost_failure || 1799 i > 1) { 1800 pr_cont("%s", "!!! "); 1801 atomic_inc(&n_rcu_torture_error); 1802 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mberror)); 1803 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mbchk_fail)); 1804 WARN_ON_ONCE(n_rcu_torture_barrier_error); // rcu_barrier() 1805 WARN_ON_ONCE(n_rcu_torture_boost_ktrerror); // no boost kthread 1806 WARN_ON_ONCE(n_rcu_torture_boost_rterror); // can't set RT prio 1807 WARN_ON_ONCE(n_rcu_torture_boost_failure); // boost failed (TIMER_SOFTIRQ RT prio?) 1808 WARN_ON_ONCE(i > 1); // Too-short grace period 1809 } 1810 pr_cont("Reader Pipe: "); 1811 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 1812 pr_cont(" %ld", pipesummary[i]); 1813 pr_cont("\n"); 1814 1815 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1816 pr_cont("Reader Batch: "); 1817 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 1818 pr_cont(" %ld", batchsummary[i]); 1819 pr_cont("\n"); 1820 1821 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1822 pr_cont("Free-Block Circulation: "); 1823 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 1824 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i])); 1825 } 1826 pr_cont("\n"); 1827 1828 if (cur_ops->stats) 1829 cur_ops->stats(); 1830 if (rtcv_snap == rcu_torture_current_version && 1831 rcu_access_pointer(rcu_torture_current) && 1832 !rcu_stall_is_suppressed()) { 1833 int __maybe_unused flags = 0; 1834 unsigned long __maybe_unused gp_seq = 0; 1835 1836 rcutorture_get_gp_data(cur_ops->ttype, 1837 &flags, &gp_seq); 1838 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, 1839 &flags, &gp_seq); 1840 wtp = READ_ONCE(writer_task); 1841 pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#x cpu %d\n", 1842 rcu_torture_writer_state_getname(), 1843 rcu_torture_writer_state, gp_seq, flags, 1844 wtp == NULL ? ~0U : wtp->__state, 1845 wtp == NULL ? -1 : (int)task_cpu(wtp)); 1846 if (!splatted && wtp) { 1847 sched_show_task(wtp); 1848 splatted = true; 1849 } 1850 if (cur_ops->gp_kthread_dbg) 1851 cur_ops->gp_kthread_dbg(); 1852 rcu_ftrace_dump(DUMP_ALL); 1853 } 1854 rtcv_snap = rcu_torture_current_version; 1855 } 1856 1857 /* 1858 * Periodically prints torture statistics, if periodic statistics printing 1859 * was specified via the stat_interval module parameter. 1860 */ 1861 static int 1862 rcu_torture_stats(void *arg) 1863 { 1864 VERBOSE_TOROUT_STRING("rcu_torture_stats task started"); 1865 do { 1866 schedule_timeout_interruptible(stat_interval * HZ); 1867 rcu_torture_stats_print(); 1868 torture_shutdown_absorb("rcu_torture_stats"); 1869 } while (!torture_must_stop()); 1870 torture_kthread_stopping("rcu_torture_stats"); 1871 return 0; 1872 } 1873 1874 /* Test mem_dump_obj() and friends. */ 1875 static void rcu_torture_mem_dump_obj(void) 1876 { 1877 struct rcu_head *rhp; 1878 struct kmem_cache *kcp; 1879 static int z; 1880 1881 kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL); 1882 rhp = kmem_cache_alloc(kcp, GFP_KERNEL); 1883 pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z); 1884 pr_alert("mem_dump_obj(ZERO_SIZE_PTR):"); 1885 mem_dump_obj(ZERO_SIZE_PTR); 1886 pr_alert("mem_dump_obj(NULL):"); 1887 mem_dump_obj(NULL); 1888 pr_alert("mem_dump_obj(%px):", &rhp); 1889 mem_dump_obj(&rhp); 1890 pr_alert("mem_dump_obj(%px):", rhp); 1891 mem_dump_obj(rhp); 1892 pr_alert("mem_dump_obj(%px):", &rhp->func); 1893 mem_dump_obj(&rhp->func); 1894 pr_alert("mem_dump_obj(%px):", &z); 1895 mem_dump_obj(&z); 1896 kmem_cache_free(kcp, rhp); 1897 kmem_cache_destroy(kcp); 1898 rhp = kmalloc(sizeof(*rhp), GFP_KERNEL); 1899 pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp); 1900 pr_alert("mem_dump_obj(kmalloc %px):", rhp); 1901 mem_dump_obj(rhp); 1902 pr_alert("mem_dump_obj(kmalloc %px):", &rhp->func); 1903 mem_dump_obj(&rhp->func); 1904 kfree(rhp); 1905 rhp = vmalloc(4096); 1906 pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp); 1907 pr_alert("mem_dump_obj(vmalloc %px):", rhp); 1908 mem_dump_obj(rhp); 1909 pr_alert("mem_dump_obj(vmalloc %px):", &rhp->func); 1910 mem_dump_obj(&rhp->func); 1911 vfree(rhp); 1912 } 1913 1914 static void 1915 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag) 1916 { 1917 pr_alert("%s" TORTURE_FLAG 1918 "--- %s: nreaders=%d nfakewriters=%d " 1919 "stat_interval=%d verbose=%d test_no_idle_hz=%d " 1920 "shuffle_interval=%d stutter=%d irqreader=%d " 1921 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d " 1922 "test_boost=%d/%d test_boost_interval=%d " 1923 "test_boost_duration=%d shutdown_secs=%d " 1924 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d " 1925 "stall_cpu_block=%d " 1926 "n_barrier_cbs=%d " 1927 "onoff_interval=%d onoff_holdoff=%d " 1928 "read_exit_delay=%d read_exit_burst=%d " 1929 "nocbs_nthreads=%d nocbs_toggle=%d\n", 1930 torture_type, tag, nrealreaders, nfakewriters, 1931 stat_interval, verbose, test_no_idle_hz, shuffle_interval, 1932 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter, 1933 test_boost, cur_ops->can_boost, 1934 test_boost_interval, test_boost_duration, shutdown_secs, 1935 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff, 1936 stall_cpu_block, 1937 n_barrier_cbs, 1938 onoff_interval, onoff_holdoff, 1939 read_exit_delay, read_exit_burst, 1940 nocbs_nthreads, nocbs_toggle); 1941 } 1942 1943 static int rcutorture_booster_cleanup(unsigned int cpu) 1944 { 1945 struct task_struct *t; 1946 1947 if (boost_tasks[cpu] == NULL) 1948 return 0; 1949 mutex_lock(&boost_mutex); 1950 t = boost_tasks[cpu]; 1951 boost_tasks[cpu] = NULL; 1952 rcu_torture_enable_rt_throttle(); 1953 mutex_unlock(&boost_mutex); 1954 1955 /* This must be outside of the mutex, otherwise deadlock! */ 1956 torture_stop_kthread(rcu_torture_boost, t); 1957 return 0; 1958 } 1959 1960 static int rcutorture_booster_init(unsigned int cpu) 1961 { 1962 int retval; 1963 1964 if (boost_tasks[cpu] != NULL) 1965 return 0; /* Already created, nothing more to do. */ 1966 1967 /* Don't allow time recalculation while creating a new task. */ 1968 mutex_lock(&boost_mutex); 1969 rcu_torture_disable_rt_throttle(); 1970 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task"); 1971 boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL, 1972 cpu_to_node(cpu), 1973 "rcu_torture_boost"); 1974 if (IS_ERR(boost_tasks[cpu])) { 1975 retval = PTR_ERR(boost_tasks[cpu]); 1976 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed"); 1977 n_rcu_torture_boost_ktrerror++; 1978 boost_tasks[cpu] = NULL; 1979 mutex_unlock(&boost_mutex); 1980 return retval; 1981 } 1982 kthread_bind(boost_tasks[cpu], cpu); 1983 wake_up_process(boost_tasks[cpu]); 1984 mutex_unlock(&boost_mutex); 1985 return 0; 1986 } 1987 1988 /* 1989 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then 1990 * induces a CPU stall for the time specified by stall_cpu. 1991 */ 1992 static int rcu_torture_stall(void *args) 1993 { 1994 int idx; 1995 unsigned long stop_at; 1996 1997 VERBOSE_TOROUT_STRING("rcu_torture_stall task started"); 1998 if (stall_cpu_holdoff > 0) { 1999 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff"); 2000 schedule_timeout_interruptible(stall_cpu_holdoff * HZ); 2001 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff"); 2002 } 2003 if (!kthread_should_stop() && stall_gp_kthread > 0) { 2004 VERBOSE_TOROUT_STRING("rcu_torture_stall begin GP stall"); 2005 rcu_gp_set_torture_wait(stall_gp_kthread * HZ); 2006 for (idx = 0; idx < stall_gp_kthread + 2; idx++) { 2007 if (kthread_should_stop()) 2008 break; 2009 schedule_timeout_uninterruptible(HZ); 2010 } 2011 } 2012 if (!kthread_should_stop() && stall_cpu > 0) { 2013 VERBOSE_TOROUT_STRING("rcu_torture_stall begin CPU stall"); 2014 stop_at = ktime_get_seconds() + stall_cpu; 2015 /* RCU CPU stall is expected behavior in following code. */ 2016 idx = cur_ops->readlock(); 2017 if (stall_cpu_irqsoff) 2018 local_irq_disable(); 2019 else if (!stall_cpu_block) 2020 preempt_disable(); 2021 pr_alert("%s start on CPU %d.\n", 2022 __func__, raw_smp_processor_id()); 2023 while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(), 2024 stop_at)) 2025 if (stall_cpu_block) { 2026 #ifdef CONFIG_PREEMPTION 2027 preempt_schedule(); 2028 #else 2029 schedule_timeout_uninterruptible(HZ); 2030 #endif 2031 } 2032 if (stall_cpu_irqsoff) 2033 local_irq_enable(); 2034 else if (!stall_cpu_block) 2035 preempt_enable(); 2036 cur_ops->readunlock(idx); 2037 } 2038 pr_alert("%s end.\n", __func__); 2039 torture_shutdown_absorb("rcu_torture_stall"); 2040 while (!kthread_should_stop()) 2041 schedule_timeout_interruptible(10 * HZ); 2042 return 0; 2043 } 2044 2045 /* Spawn CPU-stall kthread, if stall_cpu specified. */ 2046 static int __init rcu_torture_stall_init(void) 2047 { 2048 if (stall_cpu <= 0 && stall_gp_kthread <= 0) 2049 return 0; 2050 return torture_create_kthread(rcu_torture_stall, NULL, stall_task); 2051 } 2052 2053 /* State structure for forward-progress self-propagating RCU callback. */ 2054 struct fwd_cb_state { 2055 struct rcu_head rh; 2056 int stop; 2057 }; 2058 2059 /* 2060 * Forward-progress self-propagating RCU callback function. Because 2061 * callbacks run from softirq, this function is an implicit RCU read-side 2062 * critical section. 2063 */ 2064 static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp) 2065 { 2066 struct fwd_cb_state *fcsp = container_of(rhp, struct fwd_cb_state, rh); 2067 2068 if (READ_ONCE(fcsp->stop)) { 2069 WRITE_ONCE(fcsp->stop, 2); 2070 return; 2071 } 2072 cur_ops->call(&fcsp->rh, rcu_torture_fwd_prog_cb); 2073 } 2074 2075 /* State for continuous-flood RCU callbacks. */ 2076 struct rcu_fwd_cb { 2077 struct rcu_head rh; 2078 struct rcu_fwd_cb *rfc_next; 2079 struct rcu_fwd *rfc_rfp; 2080 int rfc_gps; 2081 }; 2082 2083 #define MAX_FWD_CB_JIFFIES (8 * HZ) /* Maximum CB test duration. */ 2084 #define MIN_FWD_CB_LAUNDERS 3 /* This many CB invocations to count. */ 2085 #define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */ 2086 #define FWD_CBS_HIST_DIV 10 /* Histogram buckets/second. */ 2087 #define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV)) 2088 2089 struct rcu_launder_hist { 2090 long n_launders; 2091 unsigned long launder_gp_seq; 2092 }; 2093 2094 struct rcu_fwd { 2095 spinlock_t rcu_fwd_lock; 2096 struct rcu_fwd_cb *rcu_fwd_cb_head; 2097 struct rcu_fwd_cb **rcu_fwd_cb_tail; 2098 long n_launders_cb; 2099 unsigned long rcu_fwd_startat; 2100 struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST]; 2101 unsigned long rcu_launder_gp_seq_start; 2102 }; 2103 2104 static DEFINE_MUTEX(rcu_fwd_mutex); 2105 static struct rcu_fwd *rcu_fwds; 2106 static bool rcu_fwd_emergency_stop; 2107 2108 static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp) 2109 { 2110 unsigned long gps; 2111 unsigned long gps_old; 2112 int i; 2113 int j; 2114 2115 for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--) 2116 if (rfp->n_launders_hist[i].n_launders > 0) 2117 break; 2118 pr_alert("%s: Callback-invocation histogram (duration %lu jiffies):", 2119 __func__, jiffies - rfp->rcu_fwd_startat); 2120 gps_old = rfp->rcu_launder_gp_seq_start; 2121 for (j = 0; j <= i; j++) { 2122 gps = rfp->n_launders_hist[j].launder_gp_seq; 2123 pr_cont(" %ds/%d: %ld:%ld", 2124 j + 1, FWD_CBS_HIST_DIV, 2125 rfp->n_launders_hist[j].n_launders, 2126 rcutorture_seq_diff(gps, gps_old)); 2127 gps_old = gps; 2128 } 2129 pr_cont("\n"); 2130 } 2131 2132 /* Callback function for continuous-flood RCU callbacks. */ 2133 static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp) 2134 { 2135 unsigned long flags; 2136 int i; 2137 struct rcu_fwd_cb *rfcp = container_of(rhp, struct rcu_fwd_cb, rh); 2138 struct rcu_fwd_cb **rfcpp; 2139 struct rcu_fwd *rfp = rfcp->rfc_rfp; 2140 2141 rfcp->rfc_next = NULL; 2142 rfcp->rfc_gps++; 2143 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags); 2144 rfcpp = rfp->rcu_fwd_cb_tail; 2145 rfp->rcu_fwd_cb_tail = &rfcp->rfc_next; 2146 WRITE_ONCE(*rfcpp, rfcp); 2147 WRITE_ONCE(rfp->n_launders_cb, rfp->n_launders_cb + 1); 2148 i = ((jiffies - rfp->rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV)); 2149 if (i >= ARRAY_SIZE(rfp->n_launders_hist)) 2150 i = ARRAY_SIZE(rfp->n_launders_hist) - 1; 2151 rfp->n_launders_hist[i].n_launders++; 2152 rfp->n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq(); 2153 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 2154 } 2155 2156 // Give the scheduler a chance, even on nohz_full CPUs. 2157 static void rcu_torture_fwd_prog_cond_resched(unsigned long iter) 2158 { 2159 if (IS_ENABLED(CONFIG_PREEMPTION) && IS_ENABLED(CONFIG_NO_HZ_FULL)) { 2160 // Real call_rcu() floods hit userspace, so emulate that. 2161 if (need_resched() || (iter & 0xfff)) 2162 schedule(); 2163 return; 2164 } 2165 // No userspace emulation: CB invocation throttles call_rcu() 2166 cond_resched(); 2167 } 2168 2169 /* 2170 * Free all callbacks on the rcu_fwd_cb_head list, either because the 2171 * test is over or because we hit an OOM event. 2172 */ 2173 static unsigned long rcu_torture_fwd_prog_cbfree(struct rcu_fwd *rfp) 2174 { 2175 unsigned long flags; 2176 unsigned long freed = 0; 2177 struct rcu_fwd_cb *rfcp; 2178 2179 for (;;) { 2180 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags); 2181 rfcp = rfp->rcu_fwd_cb_head; 2182 if (!rfcp) { 2183 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 2184 break; 2185 } 2186 rfp->rcu_fwd_cb_head = rfcp->rfc_next; 2187 if (!rfp->rcu_fwd_cb_head) 2188 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head; 2189 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 2190 kfree(rfcp); 2191 freed++; 2192 rcu_torture_fwd_prog_cond_resched(freed); 2193 if (tick_nohz_full_enabled()) { 2194 local_irq_save(flags); 2195 rcu_momentary_dyntick_idle(); 2196 local_irq_restore(flags); 2197 } 2198 } 2199 return freed; 2200 } 2201 2202 /* Carry out need_resched()/cond_resched() forward-progress testing. */ 2203 static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp, 2204 int *tested, int *tested_tries) 2205 { 2206 unsigned long cver; 2207 unsigned long dur; 2208 struct fwd_cb_state fcs; 2209 unsigned long gps; 2210 int idx; 2211 int sd; 2212 int sd4; 2213 bool selfpropcb = false; 2214 unsigned long stopat; 2215 static DEFINE_TORTURE_RANDOM(trs); 2216 2217 if (!cur_ops->sync) 2218 return; // Cannot do need_resched() forward progress testing without ->sync. 2219 if (cur_ops->call && cur_ops->cb_barrier) { 2220 init_rcu_head_on_stack(&fcs.rh); 2221 selfpropcb = true; 2222 } 2223 2224 /* Tight loop containing cond_resched(). */ 2225 WRITE_ONCE(rcu_fwd_cb_nodelay, true); 2226 cur_ops->sync(); /* Later readers see above write. */ 2227 if (selfpropcb) { 2228 WRITE_ONCE(fcs.stop, 0); 2229 cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb); 2230 } 2231 cver = READ_ONCE(rcu_torture_current_version); 2232 gps = cur_ops->get_gp_seq(); 2233 sd = cur_ops->stall_dur() + 1; 2234 sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div; 2235 dur = sd4 + torture_random(&trs) % (sd - sd4); 2236 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies); 2237 stopat = rfp->rcu_fwd_startat + dur; 2238 while (time_before(jiffies, stopat) && 2239 !shutdown_time_arrived() && 2240 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 2241 idx = cur_ops->readlock(); 2242 udelay(10); 2243 cur_ops->readunlock(idx); 2244 if (!fwd_progress_need_resched || need_resched()) 2245 cond_resched(); 2246 } 2247 (*tested_tries)++; 2248 if (!time_before(jiffies, stopat) && 2249 !shutdown_time_arrived() && 2250 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 2251 (*tested)++; 2252 cver = READ_ONCE(rcu_torture_current_version) - cver; 2253 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps); 2254 WARN_ON(!cver && gps < 2); 2255 pr_alert("%s: Duration %ld cver %ld gps %ld\n", __func__, dur, cver, gps); 2256 } 2257 if (selfpropcb) { 2258 WRITE_ONCE(fcs.stop, 1); 2259 cur_ops->sync(); /* Wait for running CB to complete. */ 2260 cur_ops->cb_barrier(); /* Wait for queued callbacks. */ 2261 } 2262 2263 if (selfpropcb) { 2264 WARN_ON(READ_ONCE(fcs.stop) != 2); 2265 destroy_rcu_head_on_stack(&fcs.rh); 2266 } 2267 schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */ 2268 WRITE_ONCE(rcu_fwd_cb_nodelay, false); 2269 } 2270 2271 /* Carry out call_rcu() forward-progress testing. */ 2272 static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp) 2273 { 2274 unsigned long cver; 2275 unsigned long flags; 2276 unsigned long gps; 2277 int i; 2278 long n_launders; 2279 long n_launders_cb_snap; 2280 long n_launders_sa; 2281 long n_max_cbs; 2282 long n_max_gps; 2283 struct rcu_fwd_cb *rfcp; 2284 struct rcu_fwd_cb *rfcpn; 2285 unsigned long stopat; 2286 unsigned long stoppedat; 2287 2288 if (READ_ONCE(rcu_fwd_emergency_stop)) 2289 return; /* Get out of the way quickly, no GP wait! */ 2290 if (!cur_ops->call) 2291 return; /* Can't do call_rcu() fwd prog without ->call. */ 2292 2293 /* Loop continuously posting RCU callbacks. */ 2294 WRITE_ONCE(rcu_fwd_cb_nodelay, true); 2295 cur_ops->sync(); /* Later readers see above write. */ 2296 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies); 2297 stopat = rfp->rcu_fwd_startat + MAX_FWD_CB_JIFFIES; 2298 n_launders = 0; 2299 rfp->n_launders_cb = 0; // Hoist initialization for multi-kthread 2300 n_launders_sa = 0; 2301 n_max_cbs = 0; 2302 n_max_gps = 0; 2303 for (i = 0; i < ARRAY_SIZE(rfp->n_launders_hist); i++) 2304 rfp->n_launders_hist[i].n_launders = 0; 2305 cver = READ_ONCE(rcu_torture_current_version); 2306 gps = cur_ops->get_gp_seq(); 2307 rfp->rcu_launder_gp_seq_start = gps; 2308 tick_dep_set_task(current, TICK_DEP_BIT_RCU); 2309 while (time_before(jiffies, stopat) && 2310 !shutdown_time_arrived() && 2311 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 2312 rfcp = READ_ONCE(rfp->rcu_fwd_cb_head); 2313 rfcpn = NULL; 2314 if (rfcp) 2315 rfcpn = READ_ONCE(rfcp->rfc_next); 2316 if (rfcpn) { 2317 if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS && 2318 ++n_max_gps >= MIN_FWD_CBS_LAUNDERED) 2319 break; 2320 rfp->rcu_fwd_cb_head = rfcpn; 2321 n_launders++; 2322 n_launders_sa++; 2323 } else { 2324 rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL); 2325 if (WARN_ON_ONCE(!rfcp)) { 2326 schedule_timeout_interruptible(1); 2327 continue; 2328 } 2329 n_max_cbs++; 2330 n_launders_sa = 0; 2331 rfcp->rfc_gps = 0; 2332 rfcp->rfc_rfp = rfp; 2333 } 2334 cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr); 2335 rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs); 2336 if (tick_nohz_full_enabled()) { 2337 local_irq_save(flags); 2338 rcu_momentary_dyntick_idle(); 2339 local_irq_restore(flags); 2340 } 2341 } 2342 stoppedat = jiffies; 2343 n_launders_cb_snap = READ_ONCE(rfp->n_launders_cb); 2344 cver = READ_ONCE(rcu_torture_current_version) - cver; 2345 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps); 2346 cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */ 2347 (void)rcu_torture_fwd_prog_cbfree(rfp); 2348 2349 if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) && 2350 !shutdown_time_arrived()) { 2351 WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED); 2352 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", 2353 __func__, 2354 stoppedat - rfp->rcu_fwd_startat, jiffies - stoppedat, 2355 n_launders + n_max_cbs - n_launders_cb_snap, 2356 n_launders, n_launders_sa, 2357 n_max_gps, n_max_cbs, cver, gps); 2358 rcu_torture_fwd_cb_hist(rfp); 2359 } 2360 schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */ 2361 tick_dep_clear_task(current, TICK_DEP_BIT_RCU); 2362 WRITE_ONCE(rcu_fwd_cb_nodelay, false); 2363 } 2364 2365 2366 /* 2367 * OOM notifier, but this only prints diagnostic information for the 2368 * current forward-progress test. 2369 */ 2370 static int rcutorture_oom_notify(struct notifier_block *self, 2371 unsigned long notused, void *nfreed) 2372 { 2373 struct rcu_fwd *rfp; 2374 2375 mutex_lock(&rcu_fwd_mutex); 2376 rfp = rcu_fwds; 2377 if (!rfp) { 2378 mutex_unlock(&rcu_fwd_mutex); 2379 return NOTIFY_OK; 2380 } 2381 WARN(1, "%s invoked upon OOM during forward-progress testing.\n", 2382 __func__); 2383 rcu_torture_fwd_cb_hist(rfp); 2384 rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp->rcu_fwd_startat)) / 2); 2385 WRITE_ONCE(rcu_fwd_emergency_stop, true); 2386 smp_mb(); /* Emergency stop before free and wait to avoid hangs. */ 2387 pr_info("%s: Freed %lu RCU callbacks.\n", 2388 __func__, rcu_torture_fwd_prog_cbfree(rfp)); 2389 rcu_barrier(); 2390 pr_info("%s: Freed %lu RCU callbacks.\n", 2391 __func__, rcu_torture_fwd_prog_cbfree(rfp)); 2392 rcu_barrier(); 2393 pr_info("%s: Freed %lu RCU callbacks.\n", 2394 __func__, rcu_torture_fwd_prog_cbfree(rfp)); 2395 smp_mb(); /* Frees before return to avoid redoing OOM. */ 2396 (*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */ 2397 pr_info("%s returning after OOM processing.\n", __func__); 2398 mutex_unlock(&rcu_fwd_mutex); 2399 return NOTIFY_OK; 2400 } 2401 2402 static struct notifier_block rcutorture_oom_nb = { 2403 .notifier_call = rcutorture_oom_notify 2404 }; 2405 2406 /* Carry out grace-period forward-progress testing. */ 2407 static int rcu_torture_fwd_prog(void *args) 2408 { 2409 int oldnice = task_nice(current); 2410 struct rcu_fwd *rfp = args; 2411 int tested = 0; 2412 int tested_tries = 0; 2413 2414 VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started"); 2415 rcu_bind_current_to_nocb(); 2416 if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST)) 2417 set_user_nice(current, MAX_NICE); 2418 do { 2419 schedule_timeout_interruptible(fwd_progress_holdoff * HZ); 2420 WRITE_ONCE(rcu_fwd_emergency_stop, false); 2421 if (!IS_ENABLED(CONFIG_TINY_RCU) || 2422 rcu_inkernel_boot_has_ended()) 2423 rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries); 2424 if (rcu_inkernel_boot_has_ended()) 2425 rcu_torture_fwd_prog_cr(rfp); 2426 2427 /* Avoid slow periods, better to test when busy. */ 2428 if (stutter_wait("rcu_torture_fwd_prog")) 2429 sched_set_normal(current, oldnice); 2430 } while (!torture_must_stop()); 2431 /* Short runs might not contain a valid forward-progress attempt. */ 2432 WARN_ON(!tested && tested_tries >= 5); 2433 pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries); 2434 torture_kthread_stopping("rcu_torture_fwd_prog"); 2435 return 0; 2436 } 2437 2438 /* If forward-progress checking is requested and feasible, spawn the thread. */ 2439 static int __init rcu_torture_fwd_prog_init(void) 2440 { 2441 struct rcu_fwd *rfp; 2442 2443 if (!fwd_progress) 2444 return 0; /* Not requested, so don't do it. */ 2445 if ((!cur_ops->sync && !cur_ops->call) || 2446 !cur_ops->stall_dur || cur_ops->stall_dur() <= 0 || cur_ops == &rcu_busted_ops) { 2447 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test"); 2448 return 0; 2449 } 2450 if (stall_cpu > 0) { 2451 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing"); 2452 if (IS_MODULE(CONFIG_RCU_TORTURE_TESTS)) 2453 return -EINVAL; /* In module, can fail back to user. */ 2454 WARN_ON(1); /* Make sure rcutorture notices conflict. */ 2455 return 0; 2456 } 2457 if (fwd_progress_holdoff <= 0) 2458 fwd_progress_holdoff = 1; 2459 if (fwd_progress_div <= 0) 2460 fwd_progress_div = 4; 2461 rfp = kzalloc(sizeof(*rfp), GFP_KERNEL); 2462 if (!rfp) 2463 return -ENOMEM; 2464 spin_lock_init(&rfp->rcu_fwd_lock); 2465 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head; 2466 mutex_lock(&rcu_fwd_mutex); 2467 rcu_fwds = rfp; 2468 mutex_unlock(&rcu_fwd_mutex); 2469 register_oom_notifier(&rcutorture_oom_nb); 2470 return torture_create_kthread(rcu_torture_fwd_prog, rfp, fwd_prog_task); 2471 } 2472 2473 static void rcu_torture_fwd_prog_cleanup(void) 2474 { 2475 struct rcu_fwd *rfp; 2476 2477 torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_task); 2478 rfp = rcu_fwds; 2479 mutex_lock(&rcu_fwd_mutex); 2480 rcu_fwds = NULL; 2481 mutex_unlock(&rcu_fwd_mutex); 2482 unregister_oom_notifier(&rcutorture_oom_nb); 2483 kfree(rfp); 2484 } 2485 2486 /* Callback function for RCU barrier testing. */ 2487 static void rcu_torture_barrier_cbf(struct rcu_head *rcu) 2488 { 2489 atomic_inc(&barrier_cbs_invoked); 2490 } 2491 2492 /* IPI handler to get callback posted on desired CPU, if online. */ 2493 static void rcu_torture_barrier1cb(void *rcu_void) 2494 { 2495 struct rcu_head *rhp = rcu_void; 2496 2497 cur_ops->call(rhp, rcu_torture_barrier_cbf); 2498 } 2499 2500 /* kthread function to register callbacks used to test RCU barriers. */ 2501 static int rcu_torture_barrier_cbs(void *arg) 2502 { 2503 long myid = (long)arg; 2504 bool lastphase = false; 2505 bool newphase; 2506 struct rcu_head rcu; 2507 2508 init_rcu_head_on_stack(&rcu); 2509 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started"); 2510 set_user_nice(current, MAX_NICE); 2511 do { 2512 wait_event(barrier_cbs_wq[myid], 2513 (newphase = 2514 smp_load_acquire(&barrier_phase)) != lastphase || 2515 torture_must_stop()); 2516 lastphase = newphase; 2517 if (torture_must_stop()) 2518 break; 2519 /* 2520 * The above smp_load_acquire() ensures barrier_phase load 2521 * is ordered before the following ->call(). 2522 */ 2523 if (smp_call_function_single(myid, rcu_torture_barrier1cb, 2524 &rcu, 1)) { 2525 // IPI failed, so use direct call from current CPU. 2526 cur_ops->call(&rcu, rcu_torture_barrier_cbf); 2527 } 2528 if (atomic_dec_and_test(&barrier_cbs_count)) 2529 wake_up(&barrier_wq); 2530 } while (!torture_must_stop()); 2531 if (cur_ops->cb_barrier != NULL) 2532 cur_ops->cb_barrier(); 2533 destroy_rcu_head_on_stack(&rcu); 2534 torture_kthread_stopping("rcu_torture_barrier_cbs"); 2535 return 0; 2536 } 2537 2538 /* kthread function to drive and coordinate RCU barrier testing. */ 2539 static int rcu_torture_barrier(void *arg) 2540 { 2541 int i; 2542 2543 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting"); 2544 do { 2545 atomic_set(&barrier_cbs_invoked, 0); 2546 atomic_set(&barrier_cbs_count, n_barrier_cbs); 2547 /* Ensure barrier_phase ordered after prior assignments. */ 2548 smp_store_release(&barrier_phase, !barrier_phase); 2549 for (i = 0; i < n_barrier_cbs; i++) 2550 wake_up(&barrier_cbs_wq[i]); 2551 wait_event(barrier_wq, 2552 atomic_read(&barrier_cbs_count) == 0 || 2553 torture_must_stop()); 2554 if (torture_must_stop()) 2555 break; 2556 n_barrier_attempts++; 2557 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */ 2558 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) { 2559 n_rcu_torture_barrier_error++; 2560 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n", 2561 atomic_read(&barrier_cbs_invoked), 2562 n_barrier_cbs); 2563 WARN_ON(1); 2564 // Wait manually for the remaining callbacks 2565 i = 0; 2566 do { 2567 if (WARN_ON(i++ > HZ)) 2568 i = INT_MIN; 2569 schedule_timeout_interruptible(1); 2570 cur_ops->cb_barrier(); 2571 } while (atomic_read(&barrier_cbs_invoked) != 2572 n_barrier_cbs && 2573 !torture_must_stop()); 2574 smp_mb(); // Can't trust ordering if broken. 2575 if (!torture_must_stop()) 2576 pr_err("Recovered: barrier_cbs_invoked = %d\n", 2577 atomic_read(&barrier_cbs_invoked)); 2578 } else { 2579 n_barrier_successes++; 2580 } 2581 schedule_timeout_interruptible(HZ / 10); 2582 } while (!torture_must_stop()); 2583 torture_kthread_stopping("rcu_torture_barrier"); 2584 return 0; 2585 } 2586 2587 /* Initialize RCU barrier testing. */ 2588 static int rcu_torture_barrier_init(void) 2589 { 2590 int i; 2591 int ret; 2592 2593 if (n_barrier_cbs <= 0) 2594 return 0; 2595 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) { 2596 pr_alert("%s" TORTURE_FLAG 2597 " Call or barrier ops missing for %s,\n", 2598 torture_type, cur_ops->name); 2599 pr_alert("%s" TORTURE_FLAG 2600 " RCU barrier testing omitted from run.\n", 2601 torture_type); 2602 return 0; 2603 } 2604 atomic_set(&barrier_cbs_count, 0); 2605 atomic_set(&barrier_cbs_invoked, 0); 2606 barrier_cbs_tasks = 2607 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]), 2608 GFP_KERNEL); 2609 barrier_cbs_wq = 2610 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL); 2611 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq) 2612 return -ENOMEM; 2613 for (i = 0; i < n_barrier_cbs; i++) { 2614 init_waitqueue_head(&barrier_cbs_wq[i]); 2615 ret = torture_create_kthread(rcu_torture_barrier_cbs, 2616 (void *)(long)i, 2617 barrier_cbs_tasks[i]); 2618 if (ret) 2619 return ret; 2620 } 2621 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task); 2622 } 2623 2624 /* Clean up after RCU barrier testing. */ 2625 static void rcu_torture_barrier_cleanup(void) 2626 { 2627 int i; 2628 2629 torture_stop_kthread(rcu_torture_barrier, barrier_task); 2630 if (barrier_cbs_tasks != NULL) { 2631 for (i = 0; i < n_barrier_cbs; i++) 2632 torture_stop_kthread(rcu_torture_barrier_cbs, 2633 barrier_cbs_tasks[i]); 2634 kfree(barrier_cbs_tasks); 2635 barrier_cbs_tasks = NULL; 2636 } 2637 if (barrier_cbs_wq != NULL) { 2638 kfree(barrier_cbs_wq); 2639 barrier_cbs_wq = NULL; 2640 } 2641 } 2642 2643 static bool rcu_torture_can_boost(void) 2644 { 2645 static int boost_warn_once; 2646 int prio; 2647 2648 if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2) 2649 return false; 2650 if (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state) 2651 return false; 2652 2653 prio = rcu_get_gp_kthreads_prio(); 2654 if (!prio) 2655 return false; 2656 2657 if (prio < 2) { 2658 if (boost_warn_once == 1) 2659 return false; 2660 2661 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); 2662 boost_warn_once = 1; 2663 return false; 2664 } 2665 2666 return true; 2667 } 2668 2669 static bool read_exit_child_stop; 2670 static bool read_exit_child_stopped; 2671 static wait_queue_head_t read_exit_wq; 2672 2673 // Child kthread which just does an rcutorture reader and exits. 2674 static int rcu_torture_read_exit_child(void *trsp_in) 2675 { 2676 struct torture_random_state *trsp = trsp_in; 2677 2678 set_user_nice(current, MAX_NICE); 2679 // Minimize time between reading and exiting. 2680 while (!kthread_should_stop()) 2681 schedule_timeout_uninterruptible(1); 2682 (void)rcu_torture_one_read(trsp, -1); 2683 return 0; 2684 } 2685 2686 // Parent kthread which creates and destroys read-exit child kthreads. 2687 static int rcu_torture_read_exit(void *unused) 2688 { 2689 int count = 0; 2690 bool errexit = false; 2691 int i; 2692 struct task_struct *tsp; 2693 DEFINE_TORTURE_RANDOM(trs); 2694 2695 // Allocate and initialize. 2696 set_user_nice(current, MAX_NICE); 2697 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of test"); 2698 2699 // Each pass through this loop does one read-exit episode. 2700 do { 2701 if (++count > read_exit_burst) { 2702 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: End of episode"); 2703 rcu_barrier(); // Wait for task_struct free, avoid OOM. 2704 for (i = 0; i < read_exit_delay; i++) { 2705 schedule_timeout_uninterruptible(HZ); 2706 if (READ_ONCE(read_exit_child_stop)) 2707 break; 2708 } 2709 if (!READ_ONCE(read_exit_child_stop)) 2710 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of episode"); 2711 count = 0; 2712 } 2713 if (READ_ONCE(read_exit_child_stop)) 2714 break; 2715 // Spawn child. 2716 tsp = kthread_run(rcu_torture_read_exit_child, 2717 &trs, "%s", 2718 "rcu_torture_read_exit_child"); 2719 if (IS_ERR(tsp)) { 2720 VERBOSE_TOROUT_ERRSTRING("out of memory"); 2721 errexit = true; 2722 tsp = NULL; 2723 break; 2724 } 2725 cond_resched(); 2726 kthread_stop(tsp); 2727 n_read_exits ++; 2728 stutter_wait("rcu_torture_read_exit"); 2729 } while (!errexit && !READ_ONCE(read_exit_child_stop)); 2730 2731 // Clean up and exit. 2732 smp_store_release(&read_exit_child_stopped, true); // After reaping. 2733 smp_mb(); // Store before wakeup. 2734 wake_up(&read_exit_wq); 2735 while (!torture_must_stop()) 2736 schedule_timeout_uninterruptible(1); 2737 torture_kthread_stopping("rcu_torture_read_exit"); 2738 return 0; 2739 } 2740 2741 static int rcu_torture_read_exit_init(void) 2742 { 2743 if (read_exit_burst <= 0) 2744 return -EINVAL; 2745 init_waitqueue_head(&read_exit_wq); 2746 read_exit_child_stop = false; 2747 read_exit_child_stopped = false; 2748 return torture_create_kthread(rcu_torture_read_exit, NULL, 2749 read_exit_task); 2750 } 2751 2752 static void rcu_torture_read_exit_cleanup(void) 2753 { 2754 if (!read_exit_task) 2755 return; 2756 WRITE_ONCE(read_exit_child_stop, true); 2757 smp_mb(); // Above write before wait. 2758 wait_event(read_exit_wq, smp_load_acquire(&read_exit_child_stopped)); 2759 torture_stop_kthread(rcutorture_read_exit, read_exit_task); 2760 } 2761 2762 static enum cpuhp_state rcutor_hp; 2763 2764 static void 2765 rcu_torture_cleanup(void) 2766 { 2767 int firsttime; 2768 int flags = 0; 2769 unsigned long gp_seq = 0; 2770 int i; 2771 2772 if (torture_cleanup_begin()) { 2773 if (cur_ops->cb_barrier != NULL) 2774 cur_ops->cb_barrier(); 2775 return; 2776 } 2777 if (!cur_ops) { 2778 torture_cleanup_end(); 2779 return; 2780 } 2781 2782 if (cur_ops->gp_kthread_dbg) 2783 cur_ops->gp_kthread_dbg(); 2784 rcu_torture_read_exit_cleanup(); 2785 rcu_torture_barrier_cleanup(); 2786 rcu_torture_fwd_prog_cleanup(); 2787 torture_stop_kthread(rcu_torture_stall, stall_task); 2788 torture_stop_kthread(rcu_torture_writer, writer_task); 2789 2790 if (nocb_tasks) { 2791 for (i = 0; i < nrealnocbers; i++) 2792 torture_stop_kthread(rcu_nocb_toggle, nocb_tasks[i]); 2793 kfree(nocb_tasks); 2794 nocb_tasks = NULL; 2795 } 2796 2797 if (reader_tasks) { 2798 for (i = 0; i < nrealreaders; i++) 2799 torture_stop_kthread(rcu_torture_reader, 2800 reader_tasks[i]); 2801 kfree(reader_tasks); 2802 reader_tasks = NULL; 2803 } 2804 kfree(rcu_torture_reader_mbchk); 2805 rcu_torture_reader_mbchk = NULL; 2806 2807 if (fakewriter_tasks) { 2808 for (i = 0; i < nfakewriters; i++) 2809 torture_stop_kthread(rcu_torture_fakewriter, 2810 fakewriter_tasks[i]); 2811 kfree(fakewriter_tasks); 2812 fakewriter_tasks = NULL; 2813 } 2814 2815 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq); 2816 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq); 2817 pr_alert("%s: End-test grace-period state: g%ld f%#x total-gps=%ld\n", 2818 cur_ops->name, (long)gp_seq, flags, 2819 rcutorture_seq_diff(gp_seq, start_gp_seq)); 2820 torture_stop_kthread(rcu_torture_stats, stats_task); 2821 torture_stop_kthread(rcu_torture_fqs, fqs_task); 2822 if (rcu_torture_can_boost()) 2823 cpuhp_remove_state(rcutor_hp); 2824 2825 /* 2826 * Wait for all RCU callbacks to fire, then do torture-type-specific 2827 * cleanup operations. 2828 */ 2829 if (cur_ops->cb_barrier != NULL) 2830 cur_ops->cb_barrier(); 2831 if (cur_ops->cleanup != NULL) 2832 cur_ops->cleanup(); 2833 2834 rcu_torture_mem_dump_obj(); 2835 2836 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */ 2837 2838 if (err_segs_recorded) { 2839 pr_alert("Failure/close-call rcutorture reader segments:\n"); 2840 if (rt_read_nsegs == 0) 2841 pr_alert("\t: No segments recorded!!!\n"); 2842 firsttime = 1; 2843 for (i = 0; i < rt_read_nsegs; i++) { 2844 pr_alert("\t%d: %#x ", i, err_segs[i].rt_readstate); 2845 if (err_segs[i].rt_delay_jiffies != 0) { 2846 pr_cont("%s%ldjiffies", firsttime ? "" : "+", 2847 err_segs[i].rt_delay_jiffies); 2848 firsttime = 0; 2849 } 2850 if (err_segs[i].rt_delay_ms != 0) { 2851 pr_cont("%s%ldms", firsttime ? "" : "+", 2852 err_segs[i].rt_delay_ms); 2853 firsttime = 0; 2854 } 2855 if (err_segs[i].rt_delay_us != 0) { 2856 pr_cont("%s%ldus", firsttime ? "" : "+", 2857 err_segs[i].rt_delay_us); 2858 firsttime = 0; 2859 } 2860 pr_cont("%s\n", 2861 err_segs[i].rt_preempted ? "preempted" : ""); 2862 2863 } 2864 } 2865 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error) 2866 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE"); 2867 else if (torture_onoff_failures()) 2868 rcu_torture_print_module_parms(cur_ops, 2869 "End of test: RCU_HOTPLUG"); 2870 else 2871 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS"); 2872 torture_cleanup_end(); 2873 } 2874 2875 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD 2876 static void rcu_torture_leak_cb(struct rcu_head *rhp) 2877 { 2878 } 2879 2880 static void rcu_torture_err_cb(struct rcu_head *rhp) 2881 { 2882 /* 2883 * This -might- happen due to race conditions, but is unlikely. 2884 * The scenario that leads to this happening is that the 2885 * first of the pair of duplicate callbacks is queued, 2886 * someone else starts a grace period that includes that 2887 * callback, then the second of the pair must wait for the 2888 * next grace period. Unlikely, but can happen. If it 2889 * does happen, the debug-objects subsystem won't have splatted. 2890 */ 2891 pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME); 2892 } 2893 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 2894 2895 /* 2896 * Verify that double-free causes debug-objects to complain, but only 2897 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test 2898 * cannot be carried out. 2899 */ 2900 static void rcu_test_debug_objects(void) 2901 { 2902 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD 2903 struct rcu_head rh1; 2904 struct rcu_head rh2; 2905 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_KERNEL); 2906 2907 init_rcu_head_on_stack(&rh1); 2908 init_rcu_head_on_stack(&rh2); 2909 pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME); 2910 2911 /* Try to queue the rh2 pair of callbacks for the same grace period. */ 2912 preempt_disable(); /* Prevent preemption from interrupting test. */ 2913 rcu_read_lock(); /* Make it impossible to finish a grace period. */ 2914 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */ 2915 local_irq_disable(); /* Make it harder to start a new grace period. */ 2916 call_rcu(&rh2, rcu_torture_leak_cb); 2917 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */ 2918 if (rhp) { 2919 call_rcu(rhp, rcu_torture_leak_cb); 2920 call_rcu(rhp, rcu_torture_err_cb); /* Another duplicate callback. */ 2921 } 2922 local_irq_enable(); 2923 rcu_read_unlock(); 2924 preempt_enable(); 2925 2926 /* Wait for them all to get done so we can safely return. */ 2927 rcu_barrier(); 2928 pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME); 2929 destroy_rcu_head_on_stack(&rh1); 2930 destroy_rcu_head_on_stack(&rh2); 2931 #else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 2932 pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME); 2933 #endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 2934 } 2935 2936 static void rcutorture_sync(void) 2937 { 2938 static unsigned long n; 2939 2940 if (cur_ops->sync && !(++n & 0xfff)) 2941 cur_ops->sync(); 2942 } 2943 2944 static int __init 2945 rcu_torture_init(void) 2946 { 2947 long i; 2948 int cpu; 2949 int firsterr = 0; 2950 int flags = 0; 2951 unsigned long gp_seq = 0; 2952 static struct rcu_torture_ops *torture_ops[] = { 2953 &rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops, 2954 &busted_srcud_ops, &tasks_ops, &tasks_rude_ops, 2955 &tasks_tracing_ops, &trivial_ops, 2956 }; 2957 2958 if (!torture_init_begin(torture_type, verbose)) 2959 return -EBUSY; 2960 2961 /* Process args and tell the world that the torturer is on the job. */ 2962 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) { 2963 cur_ops = torture_ops[i]; 2964 if (strcmp(torture_type, cur_ops->name) == 0) 2965 break; 2966 } 2967 if (i == ARRAY_SIZE(torture_ops)) { 2968 pr_alert("rcu-torture: invalid torture type: \"%s\"\n", 2969 torture_type); 2970 pr_alert("rcu-torture types:"); 2971 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) 2972 pr_cont(" %s", torture_ops[i]->name); 2973 pr_cont("\n"); 2974 firsterr = -EINVAL; 2975 cur_ops = NULL; 2976 goto unwind; 2977 } 2978 if (cur_ops->fqs == NULL && fqs_duration != 0) { 2979 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n"); 2980 fqs_duration = 0; 2981 } 2982 if (cur_ops->init) 2983 cur_ops->init(); 2984 2985 if (nreaders >= 0) { 2986 nrealreaders = nreaders; 2987 } else { 2988 nrealreaders = num_online_cpus() - 2 - nreaders; 2989 if (nrealreaders <= 0) 2990 nrealreaders = 1; 2991 } 2992 rcu_torture_print_module_parms(cur_ops, "Start of test"); 2993 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq); 2994 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq); 2995 start_gp_seq = gp_seq; 2996 pr_alert("%s: Start-test grace-period state: g%ld f%#x\n", 2997 cur_ops->name, (long)gp_seq, flags); 2998 2999 /* Set up the freelist. */ 3000 3001 INIT_LIST_HEAD(&rcu_torture_freelist); 3002 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) { 3003 rcu_tortures[i].rtort_mbtest = 0; 3004 list_add_tail(&rcu_tortures[i].rtort_free, 3005 &rcu_torture_freelist); 3006 } 3007 3008 /* Initialize the statistics so that each run gets its own numbers. */ 3009 3010 rcu_torture_current = NULL; 3011 rcu_torture_current_version = 0; 3012 atomic_set(&n_rcu_torture_alloc, 0); 3013 atomic_set(&n_rcu_torture_alloc_fail, 0); 3014 atomic_set(&n_rcu_torture_free, 0); 3015 atomic_set(&n_rcu_torture_mberror, 0); 3016 atomic_set(&n_rcu_torture_mbchk_fail, 0); 3017 atomic_set(&n_rcu_torture_mbchk_tries, 0); 3018 atomic_set(&n_rcu_torture_error, 0); 3019 n_rcu_torture_barrier_error = 0; 3020 n_rcu_torture_boost_ktrerror = 0; 3021 n_rcu_torture_boost_rterror = 0; 3022 n_rcu_torture_boost_failure = 0; 3023 n_rcu_torture_boosts = 0; 3024 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 3025 atomic_set(&rcu_torture_wcount[i], 0); 3026 for_each_possible_cpu(cpu) { 3027 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 3028 per_cpu(rcu_torture_count, cpu)[i] = 0; 3029 per_cpu(rcu_torture_batch, cpu)[i] = 0; 3030 } 3031 } 3032 err_segs_recorded = 0; 3033 rt_read_nsegs = 0; 3034 3035 /* Start up the kthreads. */ 3036 3037 rcu_torture_write_types(); 3038 firsterr = torture_create_kthread(rcu_torture_writer, NULL, 3039 writer_task); 3040 if (firsterr) 3041 goto unwind; 3042 if (nfakewriters > 0) { 3043 fakewriter_tasks = kcalloc(nfakewriters, 3044 sizeof(fakewriter_tasks[0]), 3045 GFP_KERNEL); 3046 if (fakewriter_tasks == NULL) { 3047 VERBOSE_TOROUT_ERRSTRING("out of memory"); 3048 firsterr = -ENOMEM; 3049 goto unwind; 3050 } 3051 } 3052 for (i = 0; i < nfakewriters; i++) { 3053 firsterr = torture_create_kthread(rcu_torture_fakewriter, 3054 NULL, fakewriter_tasks[i]); 3055 if (firsterr) 3056 goto unwind; 3057 } 3058 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]), 3059 GFP_KERNEL); 3060 rcu_torture_reader_mbchk = kcalloc(nrealreaders, sizeof(*rcu_torture_reader_mbchk), 3061 GFP_KERNEL); 3062 if (!reader_tasks || !rcu_torture_reader_mbchk) { 3063 VERBOSE_TOROUT_ERRSTRING("out of memory"); 3064 firsterr = -ENOMEM; 3065 goto unwind; 3066 } 3067 for (i = 0; i < nrealreaders; i++) { 3068 rcu_torture_reader_mbchk[i].rtc_chkrdr = -1; 3069 firsterr = torture_create_kthread(rcu_torture_reader, (void *)i, 3070 reader_tasks[i]); 3071 if (firsterr) 3072 goto unwind; 3073 } 3074 nrealnocbers = nocbs_nthreads; 3075 if (WARN_ON(nrealnocbers < 0)) 3076 nrealnocbers = 1; 3077 if (WARN_ON(nocbs_toggle < 0)) 3078 nocbs_toggle = HZ; 3079 if (nrealnocbers > 0) { 3080 nocb_tasks = kcalloc(nrealnocbers, sizeof(nocb_tasks[0]), GFP_KERNEL); 3081 if (nocb_tasks == NULL) { 3082 VERBOSE_TOROUT_ERRSTRING("out of memory"); 3083 firsterr = -ENOMEM; 3084 goto unwind; 3085 } 3086 } else { 3087 nocb_tasks = NULL; 3088 } 3089 for (i = 0; i < nrealnocbers; i++) { 3090 firsterr = torture_create_kthread(rcu_nocb_toggle, NULL, nocb_tasks[i]); 3091 if (firsterr) 3092 goto unwind; 3093 } 3094 if (stat_interval > 0) { 3095 firsterr = torture_create_kthread(rcu_torture_stats, NULL, 3096 stats_task); 3097 if (firsterr) 3098 goto unwind; 3099 } 3100 if (test_no_idle_hz && shuffle_interval > 0) { 3101 firsterr = torture_shuffle_init(shuffle_interval * HZ); 3102 if (firsterr) 3103 goto unwind; 3104 } 3105 if (stutter < 0) 3106 stutter = 0; 3107 if (stutter) { 3108 int t; 3109 3110 t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ; 3111 firsterr = torture_stutter_init(stutter * HZ, t); 3112 if (firsterr) 3113 goto unwind; 3114 } 3115 if (fqs_duration < 0) 3116 fqs_duration = 0; 3117 if (fqs_duration) { 3118 /* Create the fqs thread */ 3119 firsterr = torture_create_kthread(rcu_torture_fqs, NULL, 3120 fqs_task); 3121 if (firsterr) 3122 goto unwind; 3123 } 3124 if (test_boost_interval < 1) 3125 test_boost_interval = 1; 3126 if (test_boost_duration < 2) 3127 test_boost_duration = 2; 3128 if (rcu_torture_can_boost()) { 3129 3130 boost_starttime = jiffies + test_boost_interval * HZ; 3131 3132 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE", 3133 rcutorture_booster_init, 3134 rcutorture_booster_cleanup); 3135 if (firsterr < 0) 3136 goto unwind; 3137 rcutor_hp = firsterr; 3138 3139 // Testing RCU priority boosting requires rcutorture do 3140 // some serious abuse. Counter this by running ksoftirqd 3141 // at higher priority. 3142 if (IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)) { 3143 for_each_online_cpu(cpu) { 3144 struct sched_param sp; 3145 struct task_struct *t; 3146 3147 t = per_cpu(ksoftirqd, cpu); 3148 WARN_ON_ONCE(!t); 3149 sp.sched_priority = 2; 3150 sched_setscheduler_nocheck(t, SCHED_FIFO, &sp); 3151 } 3152 } 3153 } 3154 shutdown_jiffies = jiffies + shutdown_secs * HZ; 3155 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup); 3156 if (firsterr) 3157 goto unwind; 3158 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval, 3159 rcutorture_sync); 3160 if (firsterr) 3161 goto unwind; 3162 firsterr = rcu_torture_stall_init(); 3163 if (firsterr) 3164 goto unwind; 3165 firsterr = rcu_torture_fwd_prog_init(); 3166 if (firsterr) 3167 goto unwind; 3168 firsterr = rcu_torture_barrier_init(); 3169 if (firsterr) 3170 goto unwind; 3171 firsterr = rcu_torture_read_exit_init(); 3172 if (firsterr) 3173 goto unwind; 3174 if (object_debug) 3175 rcu_test_debug_objects(); 3176 torture_init_end(); 3177 return 0; 3178 3179 unwind: 3180 torture_init_end(); 3181 rcu_torture_cleanup(); 3182 if (shutdown_secs) { 3183 WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST)); 3184 kernel_power_off(); 3185 } 3186 return firsterr; 3187 } 3188 3189 module_init(rcu_torture_init); 3190 module_exit(rcu_torture_cleanup); 3191