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_RBH) 1436 rcu_read_lock_bh(); 1437 if (statesnew & RCUTORTURE_RDR_IRQ) 1438 local_irq_disable(); 1439 if (statesnew & RCUTORTURE_RDR_PREEMPT) 1440 preempt_disable(); 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 /* 1447 * Next, remove old protection, in decreasing order of strength 1448 * to avoid unlock paths that aren't safe in the stronger 1449 * context. Namely: BH can not be enabled with disabled interrupts. 1450 * Additionally PREEMPT_RT requires that BH is enabled in preemptible 1451 * context. 1452 */ 1453 if (statesold & RCUTORTURE_RDR_IRQ) 1454 local_irq_enable(); 1455 if (statesold & RCUTORTURE_RDR_PREEMPT) 1456 preempt_enable(); 1457 if (statesold & RCUTORTURE_RDR_SCHED) 1458 rcu_read_unlock_sched(); 1459 if (statesold & RCUTORTURE_RDR_BH) 1460 local_bh_enable(); 1461 if (statesold & RCUTORTURE_RDR_RBH) 1462 rcu_read_unlock_bh(); 1463 if (statesold & RCUTORTURE_RDR_RCU) { 1464 bool lockit = !statesnew && !(torture_random(trsp) & 0xffff); 1465 1466 if (lockit) 1467 raw_spin_lock_irqsave(¤t->pi_lock, flags); 1468 cur_ops->readunlock(idxold >> RCUTORTURE_RDR_SHIFT); 1469 if (lockit) 1470 raw_spin_unlock_irqrestore(¤t->pi_lock, flags); 1471 } 1472 1473 /* Delay if neither beginning nor end and there was a change. */ 1474 if ((statesnew || statesold) && *readstate && newstate) 1475 cur_ops->read_delay(trsp, rtrsp); 1476 1477 /* Update the reader state. */ 1478 if (idxnew == -1) 1479 idxnew = idxold & ~RCUTORTURE_RDR_MASK; 1480 WARN_ON_ONCE(idxnew < 0); 1481 WARN_ON_ONCE((idxnew >> RCUTORTURE_RDR_SHIFT) > 1); 1482 *readstate = idxnew | newstate; 1483 WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT) < 0); 1484 WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT) > 1); 1485 } 1486 1487 /* Return the biggest extendables mask given current RCU and boot parameters. */ 1488 static int rcutorture_extend_mask_max(void) 1489 { 1490 int mask; 1491 1492 WARN_ON_ONCE(extendables & ~RCUTORTURE_MAX_EXTEND); 1493 mask = extendables & RCUTORTURE_MAX_EXTEND & cur_ops->extendables; 1494 mask = mask | RCUTORTURE_RDR_RCU; 1495 return mask; 1496 } 1497 1498 /* Return a random protection state mask, but with at least one bit set. */ 1499 static int 1500 rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp) 1501 { 1502 int mask = rcutorture_extend_mask_max(); 1503 unsigned long randmask1 = torture_random(trsp) >> 8; 1504 unsigned long randmask2 = randmask1 >> 3; 1505 unsigned long preempts = RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED; 1506 unsigned long preempts_irq = preempts | RCUTORTURE_RDR_IRQ; 1507 unsigned long bhs = RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH; 1508 1509 WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT); 1510 /* Mostly only one bit (need preemption!), sometimes lots of bits. */ 1511 if (!(randmask1 & 0x7)) 1512 mask = mask & randmask2; 1513 else 1514 mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS)); 1515 1516 /* 1517 * Can't enable bh w/irq disabled. 1518 */ 1519 if (mask & RCUTORTURE_RDR_IRQ) 1520 mask |= oldmask & bhs; 1521 1522 /* 1523 * Ideally these sequences would be detected in debug builds 1524 * (regardless of RT), but until then don't stop testing 1525 * them on non-RT. 1526 */ 1527 if (IS_ENABLED(CONFIG_PREEMPT_RT)) { 1528 /* Can't modify BH in atomic context */ 1529 if (oldmask & preempts_irq) 1530 mask &= ~bhs; 1531 if ((oldmask | mask) & preempts_irq) 1532 mask |= oldmask & bhs; 1533 } 1534 1535 return mask ?: RCUTORTURE_RDR_RCU; 1536 } 1537 1538 /* 1539 * Do a randomly selected number of extensions of an existing RCU read-side 1540 * critical section. 1541 */ 1542 static struct rt_read_seg * 1543 rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp, 1544 struct rt_read_seg *rtrsp) 1545 { 1546 int i; 1547 int j; 1548 int mask = rcutorture_extend_mask_max(); 1549 1550 WARN_ON_ONCE(!*readstate); /* -Existing- RCU read-side critsect! */ 1551 if (!((mask - 1) & mask)) 1552 return rtrsp; /* Current RCU reader not extendable. */ 1553 /* Bias towards larger numbers of loops. */ 1554 i = (torture_random(trsp) >> 3); 1555 i = ((i | (i >> 3)) & RCUTORTURE_RDR_MAX_LOOPS) + 1; 1556 for (j = 0; j < i; j++) { 1557 mask = rcutorture_extend_mask(*readstate, trsp); 1558 rcutorture_one_extend(readstate, mask, trsp, &rtrsp[j]); 1559 } 1560 return &rtrsp[j]; 1561 } 1562 1563 /* 1564 * Do one read-side critical section, returning false if there was 1565 * no data to read. Can be invoked both from process context and 1566 * from a timer handler. 1567 */ 1568 static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid) 1569 { 1570 unsigned long cookie; 1571 int i; 1572 unsigned long started; 1573 unsigned long completed; 1574 int newstate; 1575 struct rcu_torture *p; 1576 int pipe_count; 1577 int readstate = 0; 1578 struct rt_read_seg rtseg[RCUTORTURE_RDR_MAX_SEGS] = { { 0 } }; 1579 struct rt_read_seg *rtrsp = &rtseg[0]; 1580 struct rt_read_seg *rtrsp1; 1581 unsigned long long ts; 1582 1583 WARN_ON_ONCE(!rcu_is_watching()); 1584 newstate = rcutorture_extend_mask(readstate, trsp); 1585 rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++); 1586 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) 1587 cookie = cur_ops->get_gp_state(); 1588 started = cur_ops->get_gp_seq(); 1589 ts = rcu_trace_clock_local(); 1590 p = rcu_dereference_check(rcu_torture_current, 1591 !cur_ops->readlock_held || cur_ops->readlock_held()); 1592 if (p == NULL) { 1593 /* Wait for rcu_torture_writer to get underway */ 1594 rcutorture_one_extend(&readstate, 0, trsp, rtrsp); 1595 return false; 1596 } 1597 if (p->rtort_mbtest == 0) 1598 atomic_inc(&n_rcu_torture_mberror); 1599 rcu_torture_reader_do_mbchk(myid, p, trsp); 1600 rtrsp = rcutorture_loop_extend(&readstate, trsp, rtrsp); 1601 preempt_disable(); 1602 pipe_count = READ_ONCE(p->rtort_pipe_count); 1603 if (pipe_count > RCU_TORTURE_PIPE_LEN) { 1604 /* Should not happen, but... */ 1605 pipe_count = RCU_TORTURE_PIPE_LEN; 1606 } 1607 completed = cur_ops->get_gp_seq(); 1608 if (pipe_count > 1) { 1609 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, 1610 ts, started, completed); 1611 rcu_ftrace_dump(DUMP_ALL); 1612 } 1613 __this_cpu_inc(rcu_torture_count[pipe_count]); 1614 completed = rcutorture_seq_diff(completed, started); 1615 if (completed > RCU_TORTURE_PIPE_LEN) { 1616 /* Should not happen, but... */ 1617 completed = RCU_TORTURE_PIPE_LEN; 1618 } 1619 __this_cpu_inc(rcu_torture_batch[completed]); 1620 preempt_enable(); 1621 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) 1622 WARN_ONCE(cur_ops->poll_gp_state(cookie), 1623 "%s: Cookie check 2 failed %s(%d) %lu->%lu\n", 1624 __func__, 1625 rcu_torture_writer_state_getname(), 1626 rcu_torture_writer_state, 1627 cookie, cur_ops->get_gp_state()); 1628 rcutorture_one_extend(&readstate, 0, trsp, rtrsp); 1629 WARN_ON_ONCE(readstate & RCUTORTURE_RDR_MASK); 1630 // This next splat is expected behavior if leakpointer, especially 1631 // for CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels. 1632 WARN_ON_ONCE(leakpointer && READ_ONCE(p->rtort_pipe_count) > 1); 1633 1634 /* If error or close call, record the sequence of reader protections. */ 1635 if ((pipe_count > 1 || completed > 1) && !xchg(&err_segs_recorded, 1)) { 1636 i = 0; 1637 for (rtrsp1 = &rtseg[0]; rtrsp1 < rtrsp; rtrsp1++) 1638 err_segs[i++] = *rtrsp1; 1639 rt_read_nsegs = i; 1640 } 1641 1642 return true; 1643 } 1644 1645 static DEFINE_TORTURE_RANDOM_PERCPU(rcu_torture_timer_rand); 1646 1647 /* 1648 * RCU torture reader from timer handler. Dereferences rcu_torture_current, 1649 * incrementing the corresponding element of the pipeline array. The 1650 * counter in the element should never be greater than 1, otherwise, the 1651 * RCU implementation is broken. 1652 */ 1653 static void rcu_torture_timer(struct timer_list *unused) 1654 { 1655 atomic_long_inc(&n_rcu_torture_timers); 1656 (void)rcu_torture_one_read(this_cpu_ptr(&rcu_torture_timer_rand), -1); 1657 1658 /* Test call_rcu() invocation from interrupt handler. */ 1659 if (cur_ops->call) { 1660 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT); 1661 1662 if (rhp) 1663 cur_ops->call(rhp, rcu_torture_timer_cb); 1664 } 1665 } 1666 1667 /* 1668 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current, 1669 * incrementing the corresponding element of the pipeline array. The 1670 * counter in the element should never be greater than 1, otherwise, the 1671 * RCU implementation is broken. 1672 */ 1673 static int 1674 rcu_torture_reader(void *arg) 1675 { 1676 unsigned long lastsleep = jiffies; 1677 long myid = (long)arg; 1678 int mynumonline = myid; 1679 DEFINE_TORTURE_RANDOM(rand); 1680 struct timer_list t; 1681 1682 VERBOSE_TOROUT_STRING("rcu_torture_reader task started"); 1683 set_user_nice(current, MAX_NICE); 1684 if (irqreader && cur_ops->irq_capable) 1685 timer_setup_on_stack(&t, rcu_torture_timer, 0); 1686 tick_dep_set_task(current, TICK_DEP_BIT_RCU); 1687 do { 1688 if (irqreader && cur_ops->irq_capable) { 1689 if (!timer_pending(&t)) 1690 mod_timer(&t, jiffies + 1); 1691 } 1692 if (!rcu_torture_one_read(&rand, myid) && !torture_must_stop()) 1693 schedule_timeout_interruptible(HZ); 1694 if (time_after(jiffies, lastsleep) && !torture_must_stop()) { 1695 torture_hrtimeout_us(500, 1000, &rand); 1696 lastsleep = jiffies + 10; 1697 } 1698 while (torture_num_online_cpus() < mynumonline && !torture_must_stop()) 1699 schedule_timeout_interruptible(HZ / 5); 1700 stutter_wait("rcu_torture_reader"); 1701 } while (!torture_must_stop()); 1702 if (irqreader && cur_ops->irq_capable) { 1703 del_timer_sync(&t); 1704 destroy_timer_on_stack(&t); 1705 } 1706 tick_dep_clear_task(current, TICK_DEP_BIT_RCU); 1707 torture_kthread_stopping("rcu_torture_reader"); 1708 return 0; 1709 } 1710 1711 /* 1712 * Randomly Toggle CPUs' callback-offload state. This uses hrtimers to 1713 * increase race probabilities and fuzzes the interval between toggling. 1714 */ 1715 static int rcu_nocb_toggle(void *arg) 1716 { 1717 int cpu; 1718 int maxcpu = -1; 1719 int oldnice = task_nice(current); 1720 long r; 1721 DEFINE_TORTURE_RANDOM(rand); 1722 ktime_t toggle_delay; 1723 unsigned long toggle_fuzz; 1724 ktime_t toggle_interval = ms_to_ktime(nocbs_toggle); 1725 1726 VERBOSE_TOROUT_STRING("rcu_nocb_toggle task started"); 1727 while (!rcu_inkernel_boot_has_ended()) 1728 schedule_timeout_interruptible(HZ / 10); 1729 for_each_online_cpu(cpu) 1730 maxcpu = cpu; 1731 WARN_ON(maxcpu < 0); 1732 if (toggle_interval > ULONG_MAX) 1733 toggle_fuzz = ULONG_MAX >> 3; 1734 else 1735 toggle_fuzz = toggle_interval >> 3; 1736 if (toggle_fuzz <= 0) 1737 toggle_fuzz = NSEC_PER_USEC; 1738 do { 1739 r = torture_random(&rand); 1740 cpu = (r >> 4) % (maxcpu + 1); 1741 if (r & 0x1) { 1742 rcu_nocb_cpu_offload(cpu); 1743 atomic_long_inc(&n_nocb_offload); 1744 } else { 1745 rcu_nocb_cpu_deoffload(cpu); 1746 atomic_long_inc(&n_nocb_deoffload); 1747 } 1748 toggle_delay = torture_random(&rand) % toggle_fuzz + toggle_interval; 1749 set_current_state(TASK_INTERRUPTIBLE); 1750 schedule_hrtimeout(&toggle_delay, HRTIMER_MODE_REL); 1751 if (stutter_wait("rcu_nocb_toggle")) 1752 sched_set_normal(current, oldnice); 1753 } while (!torture_must_stop()); 1754 torture_kthread_stopping("rcu_nocb_toggle"); 1755 return 0; 1756 } 1757 1758 /* 1759 * Print torture statistics. Caller must ensure that there is only 1760 * one call to this function at a given time!!! This is normally 1761 * accomplished by relying on the module system to only have one copy 1762 * of the module loaded, and then by giving the rcu_torture_stats 1763 * kthread full control (or the init/cleanup functions when rcu_torture_stats 1764 * thread is not running). 1765 */ 1766 static void 1767 rcu_torture_stats_print(void) 1768 { 1769 int cpu; 1770 int i; 1771 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; 1772 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; 1773 struct rcu_torture *rtcp; 1774 static unsigned long rtcv_snap = ULONG_MAX; 1775 static bool splatted; 1776 struct task_struct *wtp; 1777 1778 for_each_possible_cpu(cpu) { 1779 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 1780 pipesummary[i] += READ_ONCE(per_cpu(rcu_torture_count, cpu)[i]); 1781 batchsummary[i] += READ_ONCE(per_cpu(rcu_torture_batch, cpu)[i]); 1782 } 1783 } 1784 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) { 1785 if (pipesummary[i] != 0) 1786 break; 1787 } 1788 1789 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1790 rtcp = rcu_access_pointer(rcu_torture_current); 1791 pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ", 1792 rtcp, 1793 rtcp && !rcu_stall_is_suppressed_at_boot() ? "ver" : "VER", 1794 rcu_torture_current_version, 1795 list_empty(&rcu_torture_freelist), 1796 atomic_read(&n_rcu_torture_alloc), 1797 atomic_read(&n_rcu_torture_alloc_fail), 1798 atomic_read(&n_rcu_torture_free)); 1799 pr_cont("rtmbe: %d rtmbkf: %d/%d rtbe: %ld rtbke: %ld rtbre: %ld ", 1800 atomic_read(&n_rcu_torture_mberror), 1801 atomic_read(&n_rcu_torture_mbchk_fail), atomic_read(&n_rcu_torture_mbchk_tries), 1802 n_rcu_torture_barrier_error, 1803 n_rcu_torture_boost_ktrerror, 1804 n_rcu_torture_boost_rterror); 1805 pr_cont("rtbf: %ld rtb: %ld nt: %ld ", 1806 n_rcu_torture_boost_failure, 1807 n_rcu_torture_boosts, 1808 atomic_long_read(&n_rcu_torture_timers)); 1809 torture_onoff_stats(); 1810 pr_cont("barrier: %ld/%ld:%ld ", 1811 data_race(n_barrier_successes), 1812 data_race(n_barrier_attempts), 1813 data_race(n_rcu_torture_barrier_error)); 1814 pr_cont("read-exits: %ld ", data_race(n_read_exits)); // Statistic. 1815 pr_cont("nocb-toggles: %ld:%ld\n", 1816 atomic_long_read(&n_nocb_offload), atomic_long_read(&n_nocb_deoffload)); 1817 1818 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1819 if (atomic_read(&n_rcu_torture_mberror) || 1820 atomic_read(&n_rcu_torture_mbchk_fail) || 1821 n_rcu_torture_barrier_error || n_rcu_torture_boost_ktrerror || 1822 n_rcu_torture_boost_rterror || n_rcu_torture_boost_failure || 1823 i > 1) { 1824 pr_cont("%s", "!!! "); 1825 atomic_inc(&n_rcu_torture_error); 1826 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mberror)); 1827 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mbchk_fail)); 1828 WARN_ON_ONCE(n_rcu_torture_barrier_error); // rcu_barrier() 1829 WARN_ON_ONCE(n_rcu_torture_boost_ktrerror); // no boost kthread 1830 WARN_ON_ONCE(n_rcu_torture_boost_rterror); // can't set RT prio 1831 WARN_ON_ONCE(n_rcu_torture_boost_failure); // boost failed (TIMER_SOFTIRQ RT prio?) 1832 WARN_ON_ONCE(i > 1); // Too-short grace period 1833 } 1834 pr_cont("Reader Pipe: "); 1835 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 1836 pr_cont(" %ld", pipesummary[i]); 1837 pr_cont("\n"); 1838 1839 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1840 pr_cont("Reader Batch: "); 1841 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 1842 pr_cont(" %ld", batchsummary[i]); 1843 pr_cont("\n"); 1844 1845 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1846 pr_cont("Free-Block Circulation: "); 1847 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 1848 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i])); 1849 } 1850 pr_cont("\n"); 1851 1852 if (cur_ops->stats) 1853 cur_ops->stats(); 1854 if (rtcv_snap == rcu_torture_current_version && 1855 rcu_access_pointer(rcu_torture_current) && 1856 !rcu_stall_is_suppressed()) { 1857 int __maybe_unused flags = 0; 1858 unsigned long __maybe_unused gp_seq = 0; 1859 1860 rcutorture_get_gp_data(cur_ops->ttype, 1861 &flags, &gp_seq); 1862 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, 1863 &flags, &gp_seq); 1864 wtp = READ_ONCE(writer_task); 1865 pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#x cpu %d\n", 1866 rcu_torture_writer_state_getname(), 1867 rcu_torture_writer_state, gp_seq, flags, 1868 wtp == NULL ? ~0U : wtp->__state, 1869 wtp == NULL ? -1 : (int)task_cpu(wtp)); 1870 if (!splatted && wtp) { 1871 sched_show_task(wtp); 1872 splatted = true; 1873 } 1874 if (cur_ops->gp_kthread_dbg) 1875 cur_ops->gp_kthread_dbg(); 1876 rcu_ftrace_dump(DUMP_ALL); 1877 } 1878 rtcv_snap = rcu_torture_current_version; 1879 } 1880 1881 /* 1882 * Periodically prints torture statistics, if periodic statistics printing 1883 * was specified via the stat_interval module parameter. 1884 */ 1885 static int 1886 rcu_torture_stats(void *arg) 1887 { 1888 VERBOSE_TOROUT_STRING("rcu_torture_stats task started"); 1889 do { 1890 schedule_timeout_interruptible(stat_interval * HZ); 1891 rcu_torture_stats_print(); 1892 torture_shutdown_absorb("rcu_torture_stats"); 1893 } while (!torture_must_stop()); 1894 torture_kthread_stopping("rcu_torture_stats"); 1895 return 0; 1896 } 1897 1898 /* Test mem_dump_obj() and friends. */ 1899 static void rcu_torture_mem_dump_obj(void) 1900 { 1901 struct rcu_head *rhp; 1902 struct kmem_cache *kcp; 1903 static int z; 1904 1905 kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL); 1906 rhp = kmem_cache_alloc(kcp, GFP_KERNEL); 1907 pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z); 1908 pr_alert("mem_dump_obj(ZERO_SIZE_PTR):"); 1909 mem_dump_obj(ZERO_SIZE_PTR); 1910 pr_alert("mem_dump_obj(NULL):"); 1911 mem_dump_obj(NULL); 1912 pr_alert("mem_dump_obj(%px):", &rhp); 1913 mem_dump_obj(&rhp); 1914 pr_alert("mem_dump_obj(%px):", rhp); 1915 mem_dump_obj(rhp); 1916 pr_alert("mem_dump_obj(%px):", &rhp->func); 1917 mem_dump_obj(&rhp->func); 1918 pr_alert("mem_dump_obj(%px):", &z); 1919 mem_dump_obj(&z); 1920 kmem_cache_free(kcp, rhp); 1921 kmem_cache_destroy(kcp); 1922 rhp = kmalloc(sizeof(*rhp), GFP_KERNEL); 1923 pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp); 1924 pr_alert("mem_dump_obj(kmalloc %px):", rhp); 1925 mem_dump_obj(rhp); 1926 pr_alert("mem_dump_obj(kmalloc %px):", &rhp->func); 1927 mem_dump_obj(&rhp->func); 1928 kfree(rhp); 1929 rhp = vmalloc(4096); 1930 pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp); 1931 pr_alert("mem_dump_obj(vmalloc %px):", rhp); 1932 mem_dump_obj(rhp); 1933 pr_alert("mem_dump_obj(vmalloc %px):", &rhp->func); 1934 mem_dump_obj(&rhp->func); 1935 vfree(rhp); 1936 } 1937 1938 static void 1939 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag) 1940 { 1941 pr_alert("%s" TORTURE_FLAG 1942 "--- %s: nreaders=%d nfakewriters=%d " 1943 "stat_interval=%d verbose=%d test_no_idle_hz=%d " 1944 "shuffle_interval=%d stutter=%d irqreader=%d " 1945 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d " 1946 "test_boost=%d/%d test_boost_interval=%d " 1947 "test_boost_duration=%d shutdown_secs=%d " 1948 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d " 1949 "stall_cpu_block=%d " 1950 "n_barrier_cbs=%d " 1951 "onoff_interval=%d onoff_holdoff=%d " 1952 "read_exit_delay=%d read_exit_burst=%d " 1953 "nocbs_nthreads=%d nocbs_toggle=%d\n", 1954 torture_type, tag, nrealreaders, nfakewriters, 1955 stat_interval, verbose, test_no_idle_hz, shuffle_interval, 1956 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter, 1957 test_boost, cur_ops->can_boost, 1958 test_boost_interval, test_boost_duration, shutdown_secs, 1959 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff, 1960 stall_cpu_block, 1961 n_barrier_cbs, 1962 onoff_interval, onoff_holdoff, 1963 read_exit_delay, read_exit_burst, 1964 nocbs_nthreads, nocbs_toggle); 1965 } 1966 1967 static int rcutorture_booster_cleanup(unsigned int cpu) 1968 { 1969 struct task_struct *t; 1970 1971 if (boost_tasks[cpu] == NULL) 1972 return 0; 1973 mutex_lock(&boost_mutex); 1974 t = boost_tasks[cpu]; 1975 boost_tasks[cpu] = NULL; 1976 rcu_torture_enable_rt_throttle(); 1977 mutex_unlock(&boost_mutex); 1978 1979 /* This must be outside of the mutex, otherwise deadlock! */ 1980 torture_stop_kthread(rcu_torture_boost, t); 1981 return 0; 1982 } 1983 1984 static int rcutorture_booster_init(unsigned int cpu) 1985 { 1986 int retval; 1987 1988 if (boost_tasks[cpu] != NULL) 1989 return 0; /* Already created, nothing more to do. */ 1990 1991 /* Don't allow time recalculation while creating a new task. */ 1992 mutex_lock(&boost_mutex); 1993 rcu_torture_disable_rt_throttle(); 1994 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task"); 1995 boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL, 1996 cpu_to_node(cpu), 1997 "rcu_torture_boost"); 1998 if (IS_ERR(boost_tasks[cpu])) { 1999 retval = PTR_ERR(boost_tasks[cpu]); 2000 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed"); 2001 n_rcu_torture_boost_ktrerror++; 2002 boost_tasks[cpu] = NULL; 2003 mutex_unlock(&boost_mutex); 2004 return retval; 2005 } 2006 kthread_bind(boost_tasks[cpu], cpu); 2007 wake_up_process(boost_tasks[cpu]); 2008 mutex_unlock(&boost_mutex); 2009 return 0; 2010 } 2011 2012 /* 2013 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then 2014 * induces a CPU stall for the time specified by stall_cpu. 2015 */ 2016 static int rcu_torture_stall(void *args) 2017 { 2018 int idx; 2019 unsigned long stop_at; 2020 2021 VERBOSE_TOROUT_STRING("rcu_torture_stall task started"); 2022 if (stall_cpu_holdoff > 0) { 2023 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff"); 2024 schedule_timeout_interruptible(stall_cpu_holdoff * HZ); 2025 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff"); 2026 } 2027 if (!kthread_should_stop() && stall_gp_kthread > 0) { 2028 VERBOSE_TOROUT_STRING("rcu_torture_stall begin GP stall"); 2029 rcu_gp_set_torture_wait(stall_gp_kthread * HZ); 2030 for (idx = 0; idx < stall_gp_kthread + 2; idx++) { 2031 if (kthread_should_stop()) 2032 break; 2033 schedule_timeout_uninterruptible(HZ); 2034 } 2035 } 2036 if (!kthread_should_stop() && stall_cpu > 0) { 2037 VERBOSE_TOROUT_STRING("rcu_torture_stall begin CPU stall"); 2038 stop_at = ktime_get_seconds() + stall_cpu; 2039 /* RCU CPU stall is expected behavior in following code. */ 2040 idx = cur_ops->readlock(); 2041 if (stall_cpu_irqsoff) 2042 local_irq_disable(); 2043 else if (!stall_cpu_block) 2044 preempt_disable(); 2045 pr_alert("%s start on CPU %d.\n", 2046 __func__, raw_smp_processor_id()); 2047 while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(), 2048 stop_at)) 2049 if (stall_cpu_block) { 2050 #ifdef CONFIG_PREEMPTION 2051 preempt_schedule(); 2052 #else 2053 schedule_timeout_uninterruptible(HZ); 2054 #endif 2055 } 2056 if (stall_cpu_irqsoff) 2057 local_irq_enable(); 2058 else if (!stall_cpu_block) 2059 preempt_enable(); 2060 cur_ops->readunlock(idx); 2061 } 2062 pr_alert("%s end.\n", __func__); 2063 torture_shutdown_absorb("rcu_torture_stall"); 2064 while (!kthread_should_stop()) 2065 schedule_timeout_interruptible(10 * HZ); 2066 return 0; 2067 } 2068 2069 /* Spawn CPU-stall kthread, if stall_cpu specified. */ 2070 static int __init rcu_torture_stall_init(void) 2071 { 2072 if (stall_cpu <= 0 && stall_gp_kthread <= 0) 2073 return 0; 2074 return torture_create_kthread(rcu_torture_stall, NULL, stall_task); 2075 } 2076 2077 /* State structure for forward-progress self-propagating RCU callback. */ 2078 struct fwd_cb_state { 2079 struct rcu_head rh; 2080 int stop; 2081 }; 2082 2083 /* 2084 * Forward-progress self-propagating RCU callback function. Because 2085 * callbacks run from softirq, this function is an implicit RCU read-side 2086 * critical section. 2087 */ 2088 static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp) 2089 { 2090 struct fwd_cb_state *fcsp = container_of(rhp, struct fwd_cb_state, rh); 2091 2092 if (READ_ONCE(fcsp->stop)) { 2093 WRITE_ONCE(fcsp->stop, 2); 2094 return; 2095 } 2096 cur_ops->call(&fcsp->rh, rcu_torture_fwd_prog_cb); 2097 } 2098 2099 /* State for continuous-flood RCU callbacks. */ 2100 struct rcu_fwd_cb { 2101 struct rcu_head rh; 2102 struct rcu_fwd_cb *rfc_next; 2103 struct rcu_fwd *rfc_rfp; 2104 int rfc_gps; 2105 }; 2106 2107 #define MAX_FWD_CB_JIFFIES (8 * HZ) /* Maximum CB test duration. */ 2108 #define MIN_FWD_CB_LAUNDERS 3 /* This many CB invocations to count. */ 2109 #define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */ 2110 #define FWD_CBS_HIST_DIV 10 /* Histogram buckets/second. */ 2111 #define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV)) 2112 2113 struct rcu_launder_hist { 2114 long n_launders; 2115 unsigned long launder_gp_seq; 2116 }; 2117 2118 struct rcu_fwd { 2119 spinlock_t rcu_fwd_lock; 2120 struct rcu_fwd_cb *rcu_fwd_cb_head; 2121 struct rcu_fwd_cb **rcu_fwd_cb_tail; 2122 long n_launders_cb; 2123 unsigned long rcu_fwd_startat; 2124 struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST]; 2125 unsigned long rcu_launder_gp_seq_start; 2126 }; 2127 2128 static DEFINE_MUTEX(rcu_fwd_mutex); 2129 static struct rcu_fwd *rcu_fwds; 2130 static bool rcu_fwd_emergency_stop; 2131 2132 static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp) 2133 { 2134 unsigned long gps; 2135 unsigned long gps_old; 2136 int i; 2137 int j; 2138 2139 for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--) 2140 if (rfp->n_launders_hist[i].n_launders > 0) 2141 break; 2142 pr_alert("%s: Callback-invocation histogram (duration %lu jiffies):", 2143 __func__, jiffies - rfp->rcu_fwd_startat); 2144 gps_old = rfp->rcu_launder_gp_seq_start; 2145 for (j = 0; j <= i; j++) { 2146 gps = rfp->n_launders_hist[j].launder_gp_seq; 2147 pr_cont(" %ds/%d: %ld:%ld", 2148 j + 1, FWD_CBS_HIST_DIV, 2149 rfp->n_launders_hist[j].n_launders, 2150 rcutorture_seq_diff(gps, gps_old)); 2151 gps_old = gps; 2152 } 2153 pr_cont("\n"); 2154 } 2155 2156 /* Callback function for continuous-flood RCU callbacks. */ 2157 static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp) 2158 { 2159 unsigned long flags; 2160 int i; 2161 struct rcu_fwd_cb *rfcp = container_of(rhp, struct rcu_fwd_cb, rh); 2162 struct rcu_fwd_cb **rfcpp; 2163 struct rcu_fwd *rfp = rfcp->rfc_rfp; 2164 2165 rfcp->rfc_next = NULL; 2166 rfcp->rfc_gps++; 2167 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags); 2168 rfcpp = rfp->rcu_fwd_cb_tail; 2169 rfp->rcu_fwd_cb_tail = &rfcp->rfc_next; 2170 WRITE_ONCE(*rfcpp, rfcp); 2171 WRITE_ONCE(rfp->n_launders_cb, rfp->n_launders_cb + 1); 2172 i = ((jiffies - rfp->rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV)); 2173 if (i >= ARRAY_SIZE(rfp->n_launders_hist)) 2174 i = ARRAY_SIZE(rfp->n_launders_hist) - 1; 2175 rfp->n_launders_hist[i].n_launders++; 2176 rfp->n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq(); 2177 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 2178 } 2179 2180 // Give the scheduler a chance, even on nohz_full CPUs. 2181 static void rcu_torture_fwd_prog_cond_resched(unsigned long iter) 2182 { 2183 if (IS_ENABLED(CONFIG_PREEMPTION) && IS_ENABLED(CONFIG_NO_HZ_FULL)) { 2184 // Real call_rcu() floods hit userspace, so emulate that. 2185 if (need_resched() || (iter & 0xfff)) 2186 schedule(); 2187 return; 2188 } 2189 // No userspace emulation: CB invocation throttles call_rcu() 2190 cond_resched(); 2191 } 2192 2193 /* 2194 * Free all callbacks on the rcu_fwd_cb_head list, either because the 2195 * test is over or because we hit an OOM event. 2196 */ 2197 static unsigned long rcu_torture_fwd_prog_cbfree(struct rcu_fwd *rfp) 2198 { 2199 unsigned long flags; 2200 unsigned long freed = 0; 2201 struct rcu_fwd_cb *rfcp; 2202 2203 for (;;) { 2204 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags); 2205 rfcp = rfp->rcu_fwd_cb_head; 2206 if (!rfcp) { 2207 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 2208 break; 2209 } 2210 rfp->rcu_fwd_cb_head = rfcp->rfc_next; 2211 if (!rfp->rcu_fwd_cb_head) 2212 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head; 2213 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 2214 kfree(rfcp); 2215 freed++; 2216 rcu_torture_fwd_prog_cond_resched(freed); 2217 if (tick_nohz_full_enabled()) { 2218 local_irq_save(flags); 2219 rcu_momentary_dyntick_idle(); 2220 local_irq_restore(flags); 2221 } 2222 } 2223 return freed; 2224 } 2225 2226 /* Carry out need_resched()/cond_resched() forward-progress testing. */ 2227 static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp, 2228 int *tested, int *tested_tries) 2229 { 2230 unsigned long cver; 2231 unsigned long dur; 2232 struct fwd_cb_state fcs; 2233 unsigned long gps; 2234 int idx; 2235 int sd; 2236 int sd4; 2237 bool selfpropcb = false; 2238 unsigned long stopat; 2239 static DEFINE_TORTURE_RANDOM(trs); 2240 2241 if (!cur_ops->sync) 2242 return; // Cannot do need_resched() forward progress testing without ->sync. 2243 if (cur_ops->call && cur_ops->cb_barrier) { 2244 init_rcu_head_on_stack(&fcs.rh); 2245 selfpropcb = true; 2246 } 2247 2248 /* Tight loop containing cond_resched(). */ 2249 WRITE_ONCE(rcu_fwd_cb_nodelay, true); 2250 cur_ops->sync(); /* Later readers see above write. */ 2251 if (selfpropcb) { 2252 WRITE_ONCE(fcs.stop, 0); 2253 cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb); 2254 } 2255 cver = READ_ONCE(rcu_torture_current_version); 2256 gps = cur_ops->get_gp_seq(); 2257 sd = cur_ops->stall_dur() + 1; 2258 sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div; 2259 dur = sd4 + torture_random(&trs) % (sd - sd4); 2260 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies); 2261 stopat = rfp->rcu_fwd_startat + dur; 2262 while (time_before(jiffies, stopat) && 2263 !shutdown_time_arrived() && 2264 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 2265 idx = cur_ops->readlock(); 2266 udelay(10); 2267 cur_ops->readunlock(idx); 2268 if (!fwd_progress_need_resched || need_resched()) 2269 cond_resched(); 2270 } 2271 (*tested_tries)++; 2272 if (!time_before(jiffies, stopat) && 2273 !shutdown_time_arrived() && 2274 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 2275 (*tested)++; 2276 cver = READ_ONCE(rcu_torture_current_version) - cver; 2277 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps); 2278 WARN_ON(!cver && gps < 2); 2279 pr_alert("%s: Duration %ld cver %ld gps %ld\n", __func__, dur, cver, gps); 2280 } 2281 if (selfpropcb) { 2282 WRITE_ONCE(fcs.stop, 1); 2283 cur_ops->sync(); /* Wait for running CB to complete. */ 2284 cur_ops->cb_barrier(); /* Wait for queued callbacks. */ 2285 } 2286 2287 if (selfpropcb) { 2288 WARN_ON(READ_ONCE(fcs.stop) != 2); 2289 destroy_rcu_head_on_stack(&fcs.rh); 2290 } 2291 schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */ 2292 WRITE_ONCE(rcu_fwd_cb_nodelay, false); 2293 } 2294 2295 /* Carry out call_rcu() forward-progress testing. */ 2296 static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp) 2297 { 2298 unsigned long cver; 2299 unsigned long flags; 2300 unsigned long gps; 2301 int i; 2302 long n_launders; 2303 long n_launders_cb_snap; 2304 long n_launders_sa; 2305 long n_max_cbs; 2306 long n_max_gps; 2307 struct rcu_fwd_cb *rfcp; 2308 struct rcu_fwd_cb *rfcpn; 2309 unsigned long stopat; 2310 unsigned long stoppedat; 2311 2312 if (READ_ONCE(rcu_fwd_emergency_stop)) 2313 return; /* Get out of the way quickly, no GP wait! */ 2314 if (!cur_ops->call) 2315 return; /* Can't do call_rcu() fwd prog without ->call. */ 2316 2317 /* Loop continuously posting RCU callbacks. */ 2318 WRITE_ONCE(rcu_fwd_cb_nodelay, true); 2319 cur_ops->sync(); /* Later readers see above write. */ 2320 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies); 2321 stopat = rfp->rcu_fwd_startat + MAX_FWD_CB_JIFFIES; 2322 n_launders = 0; 2323 rfp->n_launders_cb = 0; // Hoist initialization for multi-kthread 2324 n_launders_sa = 0; 2325 n_max_cbs = 0; 2326 n_max_gps = 0; 2327 for (i = 0; i < ARRAY_SIZE(rfp->n_launders_hist); i++) 2328 rfp->n_launders_hist[i].n_launders = 0; 2329 cver = READ_ONCE(rcu_torture_current_version); 2330 gps = cur_ops->get_gp_seq(); 2331 rfp->rcu_launder_gp_seq_start = gps; 2332 tick_dep_set_task(current, TICK_DEP_BIT_RCU); 2333 while (time_before(jiffies, stopat) && 2334 !shutdown_time_arrived() && 2335 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 2336 rfcp = READ_ONCE(rfp->rcu_fwd_cb_head); 2337 rfcpn = NULL; 2338 if (rfcp) 2339 rfcpn = READ_ONCE(rfcp->rfc_next); 2340 if (rfcpn) { 2341 if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS && 2342 ++n_max_gps >= MIN_FWD_CBS_LAUNDERED) 2343 break; 2344 rfp->rcu_fwd_cb_head = rfcpn; 2345 n_launders++; 2346 n_launders_sa++; 2347 } else { 2348 rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL); 2349 if (WARN_ON_ONCE(!rfcp)) { 2350 schedule_timeout_interruptible(1); 2351 continue; 2352 } 2353 n_max_cbs++; 2354 n_launders_sa = 0; 2355 rfcp->rfc_gps = 0; 2356 rfcp->rfc_rfp = rfp; 2357 } 2358 cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr); 2359 rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs); 2360 if (tick_nohz_full_enabled()) { 2361 local_irq_save(flags); 2362 rcu_momentary_dyntick_idle(); 2363 local_irq_restore(flags); 2364 } 2365 } 2366 stoppedat = jiffies; 2367 n_launders_cb_snap = READ_ONCE(rfp->n_launders_cb); 2368 cver = READ_ONCE(rcu_torture_current_version) - cver; 2369 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps); 2370 cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */ 2371 (void)rcu_torture_fwd_prog_cbfree(rfp); 2372 2373 if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) && 2374 !shutdown_time_arrived()) { 2375 WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED); 2376 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", 2377 __func__, 2378 stoppedat - rfp->rcu_fwd_startat, jiffies - stoppedat, 2379 n_launders + n_max_cbs - n_launders_cb_snap, 2380 n_launders, n_launders_sa, 2381 n_max_gps, n_max_cbs, cver, gps); 2382 rcu_torture_fwd_cb_hist(rfp); 2383 } 2384 schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */ 2385 tick_dep_clear_task(current, TICK_DEP_BIT_RCU); 2386 WRITE_ONCE(rcu_fwd_cb_nodelay, false); 2387 } 2388 2389 2390 /* 2391 * OOM notifier, but this only prints diagnostic information for the 2392 * current forward-progress test. 2393 */ 2394 static int rcutorture_oom_notify(struct notifier_block *self, 2395 unsigned long notused, void *nfreed) 2396 { 2397 struct rcu_fwd *rfp; 2398 2399 mutex_lock(&rcu_fwd_mutex); 2400 rfp = rcu_fwds; 2401 if (!rfp) { 2402 mutex_unlock(&rcu_fwd_mutex); 2403 return NOTIFY_OK; 2404 } 2405 WARN(1, "%s invoked upon OOM during forward-progress testing.\n", 2406 __func__); 2407 rcu_torture_fwd_cb_hist(rfp); 2408 rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp->rcu_fwd_startat)) / 2); 2409 WRITE_ONCE(rcu_fwd_emergency_stop, true); 2410 smp_mb(); /* Emergency stop before free and wait to avoid hangs. */ 2411 pr_info("%s: Freed %lu RCU callbacks.\n", 2412 __func__, rcu_torture_fwd_prog_cbfree(rfp)); 2413 rcu_barrier(); 2414 pr_info("%s: Freed %lu RCU callbacks.\n", 2415 __func__, rcu_torture_fwd_prog_cbfree(rfp)); 2416 rcu_barrier(); 2417 pr_info("%s: Freed %lu RCU callbacks.\n", 2418 __func__, rcu_torture_fwd_prog_cbfree(rfp)); 2419 smp_mb(); /* Frees before return to avoid redoing OOM. */ 2420 (*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */ 2421 pr_info("%s returning after OOM processing.\n", __func__); 2422 mutex_unlock(&rcu_fwd_mutex); 2423 return NOTIFY_OK; 2424 } 2425 2426 static struct notifier_block rcutorture_oom_nb = { 2427 .notifier_call = rcutorture_oom_notify 2428 }; 2429 2430 /* Carry out grace-period forward-progress testing. */ 2431 static int rcu_torture_fwd_prog(void *args) 2432 { 2433 int oldnice = task_nice(current); 2434 struct rcu_fwd *rfp = args; 2435 int tested = 0; 2436 int tested_tries = 0; 2437 2438 VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started"); 2439 rcu_bind_current_to_nocb(); 2440 if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST)) 2441 set_user_nice(current, MAX_NICE); 2442 do { 2443 schedule_timeout_interruptible(fwd_progress_holdoff * HZ); 2444 WRITE_ONCE(rcu_fwd_emergency_stop, false); 2445 if (!IS_ENABLED(CONFIG_TINY_RCU) || 2446 rcu_inkernel_boot_has_ended()) 2447 rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries); 2448 if (rcu_inkernel_boot_has_ended()) 2449 rcu_torture_fwd_prog_cr(rfp); 2450 2451 /* Avoid slow periods, better to test when busy. */ 2452 if (stutter_wait("rcu_torture_fwd_prog")) 2453 sched_set_normal(current, oldnice); 2454 } while (!torture_must_stop()); 2455 /* Short runs might not contain a valid forward-progress attempt. */ 2456 WARN_ON(!tested && tested_tries >= 5); 2457 pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries); 2458 torture_kthread_stopping("rcu_torture_fwd_prog"); 2459 return 0; 2460 } 2461 2462 /* If forward-progress checking is requested and feasible, spawn the thread. */ 2463 static int __init rcu_torture_fwd_prog_init(void) 2464 { 2465 struct rcu_fwd *rfp; 2466 2467 if (!fwd_progress) 2468 return 0; /* Not requested, so don't do it. */ 2469 if ((!cur_ops->sync && !cur_ops->call) || 2470 !cur_ops->stall_dur || cur_ops->stall_dur() <= 0 || cur_ops == &rcu_busted_ops) { 2471 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test"); 2472 return 0; 2473 } 2474 if (stall_cpu > 0) { 2475 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing"); 2476 if (IS_MODULE(CONFIG_RCU_TORTURE_TEST)) 2477 return -EINVAL; /* In module, can fail back to user. */ 2478 WARN_ON(1); /* Make sure rcutorture notices conflict. */ 2479 return 0; 2480 } 2481 if (fwd_progress_holdoff <= 0) 2482 fwd_progress_holdoff = 1; 2483 if (fwd_progress_div <= 0) 2484 fwd_progress_div = 4; 2485 rfp = kzalloc(sizeof(*rfp), GFP_KERNEL); 2486 if (!rfp) 2487 return -ENOMEM; 2488 spin_lock_init(&rfp->rcu_fwd_lock); 2489 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head; 2490 mutex_lock(&rcu_fwd_mutex); 2491 rcu_fwds = rfp; 2492 mutex_unlock(&rcu_fwd_mutex); 2493 register_oom_notifier(&rcutorture_oom_nb); 2494 return torture_create_kthread(rcu_torture_fwd_prog, rfp, fwd_prog_task); 2495 } 2496 2497 static void rcu_torture_fwd_prog_cleanup(void) 2498 { 2499 struct rcu_fwd *rfp; 2500 2501 torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_task); 2502 rfp = rcu_fwds; 2503 mutex_lock(&rcu_fwd_mutex); 2504 rcu_fwds = NULL; 2505 mutex_unlock(&rcu_fwd_mutex); 2506 unregister_oom_notifier(&rcutorture_oom_nb); 2507 kfree(rfp); 2508 } 2509 2510 /* Callback function for RCU barrier testing. */ 2511 static void rcu_torture_barrier_cbf(struct rcu_head *rcu) 2512 { 2513 atomic_inc(&barrier_cbs_invoked); 2514 } 2515 2516 /* IPI handler to get callback posted on desired CPU, if online. */ 2517 static void rcu_torture_barrier1cb(void *rcu_void) 2518 { 2519 struct rcu_head *rhp = rcu_void; 2520 2521 cur_ops->call(rhp, rcu_torture_barrier_cbf); 2522 } 2523 2524 /* kthread function to register callbacks used to test RCU barriers. */ 2525 static int rcu_torture_barrier_cbs(void *arg) 2526 { 2527 long myid = (long)arg; 2528 bool lastphase = false; 2529 bool newphase; 2530 struct rcu_head rcu; 2531 2532 init_rcu_head_on_stack(&rcu); 2533 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started"); 2534 set_user_nice(current, MAX_NICE); 2535 do { 2536 wait_event(barrier_cbs_wq[myid], 2537 (newphase = 2538 smp_load_acquire(&barrier_phase)) != lastphase || 2539 torture_must_stop()); 2540 lastphase = newphase; 2541 if (torture_must_stop()) 2542 break; 2543 /* 2544 * The above smp_load_acquire() ensures barrier_phase load 2545 * is ordered before the following ->call(). 2546 */ 2547 if (smp_call_function_single(myid, rcu_torture_barrier1cb, 2548 &rcu, 1)) { 2549 // IPI failed, so use direct call from current CPU. 2550 cur_ops->call(&rcu, rcu_torture_barrier_cbf); 2551 } 2552 if (atomic_dec_and_test(&barrier_cbs_count)) 2553 wake_up(&barrier_wq); 2554 } while (!torture_must_stop()); 2555 if (cur_ops->cb_barrier != NULL) 2556 cur_ops->cb_barrier(); 2557 destroy_rcu_head_on_stack(&rcu); 2558 torture_kthread_stopping("rcu_torture_barrier_cbs"); 2559 return 0; 2560 } 2561 2562 /* kthread function to drive and coordinate RCU barrier testing. */ 2563 static int rcu_torture_barrier(void *arg) 2564 { 2565 int i; 2566 2567 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting"); 2568 do { 2569 atomic_set(&barrier_cbs_invoked, 0); 2570 atomic_set(&barrier_cbs_count, n_barrier_cbs); 2571 /* Ensure barrier_phase ordered after prior assignments. */ 2572 smp_store_release(&barrier_phase, !barrier_phase); 2573 for (i = 0; i < n_barrier_cbs; i++) 2574 wake_up(&barrier_cbs_wq[i]); 2575 wait_event(barrier_wq, 2576 atomic_read(&barrier_cbs_count) == 0 || 2577 torture_must_stop()); 2578 if (torture_must_stop()) 2579 break; 2580 n_barrier_attempts++; 2581 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */ 2582 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) { 2583 n_rcu_torture_barrier_error++; 2584 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n", 2585 atomic_read(&barrier_cbs_invoked), 2586 n_barrier_cbs); 2587 WARN_ON(1); 2588 // Wait manually for the remaining callbacks 2589 i = 0; 2590 do { 2591 if (WARN_ON(i++ > HZ)) 2592 i = INT_MIN; 2593 schedule_timeout_interruptible(1); 2594 cur_ops->cb_barrier(); 2595 } while (atomic_read(&barrier_cbs_invoked) != 2596 n_barrier_cbs && 2597 !torture_must_stop()); 2598 smp_mb(); // Can't trust ordering if broken. 2599 if (!torture_must_stop()) 2600 pr_err("Recovered: barrier_cbs_invoked = %d\n", 2601 atomic_read(&barrier_cbs_invoked)); 2602 } else { 2603 n_barrier_successes++; 2604 } 2605 schedule_timeout_interruptible(HZ / 10); 2606 } while (!torture_must_stop()); 2607 torture_kthread_stopping("rcu_torture_barrier"); 2608 return 0; 2609 } 2610 2611 /* Initialize RCU barrier testing. */ 2612 static int rcu_torture_barrier_init(void) 2613 { 2614 int i; 2615 int ret; 2616 2617 if (n_barrier_cbs <= 0) 2618 return 0; 2619 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) { 2620 pr_alert("%s" TORTURE_FLAG 2621 " Call or barrier ops missing for %s,\n", 2622 torture_type, cur_ops->name); 2623 pr_alert("%s" TORTURE_FLAG 2624 " RCU barrier testing omitted from run.\n", 2625 torture_type); 2626 return 0; 2627 } 2628 atomic_set(&barrier_cbs_count, 0); 2629 atomic_set(&barrier_cbs_invoked, 0); 2630 barrier_cbs_tasks = 2631 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]), 2632 GFP_KERNEL); 2633 barrier_cbs_wq = 2634 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL); 2635 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq) 2636 return -ENOMEM; 2637 for (i = 0; i < n_barrier_cbs; i++) { 2638 init_waitqueue_head(&barrier_cbs_wq[i]); 2639 ret = torture_create_kthread(rcu_torture_barrier_cbs, 2640 (void *)(long)i, 2641 barrier_cbs_tasks[i]); 2642 if (ret) 2643 return ret; 2644 } 2645 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task); 2646 } 2647 2648 /* Clean up after RCU barrier testing. */ 2649 static void rcu_torture_barrier_cleanup(void) 2650 { 2651 int i; 2652 2653 torture_stop_kthread(rcu_torture_barrier, barrier_task); 2654 if (barrier_cbs_tasks != NULL) { 2655 for (i = 0; i < n_barrier_cbs; i++) 2656 torture_stop_kthread(rcu_torture_barrier_cbs, 2657 barrier_cbs_tasks[i]); 2658 kfree(barrier_cbs_tasks); 2659 barrier_cbs_tasks = NULL; 2660 } 2661 if (barrier_cbs_wq != NULL) { 2662 kfree(barrier_cbs_wq); 2663 barrier_cbs_wq = NULL; 2664 } 2665 } 2666 2667 static bool rcu_torture_can_boost(void) 2668 { 2669 static int boost_warn_once; 2670 int prio; 2671 2672 if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2) 2673 return false; 2674 if (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state) 2675 return false; 2676 2677 prio = rcu_get_gp_kthreads_prio(); 2678 if (!prio) 2679 return false; 2680 2681 if (prio < 2) { 2682 if (boost_warn_once == 1) 2683 return false; 2684 2685 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); 2686 boost_warn_once = 1; 2687 return false; 2688 } 2689 2690 return true; 2691 } 2692 2693 static bool read_exit_child_stop; 2694 static bool read_exit_child_stopped; 2695 static wait_queue_head_t read_exit_wq; 2696 2697 // Child kthread which just does an rcutorture reader and exits. 2698 static int rcu_torture_read_exit_child(void *trsp_in) 2699 { 2700 struct torture_random_state *trsp = trsp_in; 2701 2702 set_user_nice(current, MAX_NICE); 2703 // Minimize time between reading and exiting. 2704 while (!kthread_should_stop()) 2705 schedule_timeout_uninterruptible(1); 2706 (void)rcu_torture_one_read(trsp, -1); 2707 return 0; 2708 } 2709 2710 // Parent kthread which creates and destroys read-exit child kthreads. 2711 static int rcu_torture_read_exit(void *unused) 2712 { 2713 int count = 0; 2714 bool errexit = false; 2715 int i; 2716 struct task_struct *tsp; 2717 DEFINE_TORTURE_RANDOM(trs); 2718 2719 // Allocate and initialize. 2720 set_user_nice(current, MAX_NICE); 2721 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of test"); 2722 2723 // Each pass through this loop does one read-exit episode. 2724 do { 2725 if (++count > read_exit_burst) { 2726 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: End of episode"); 2727 rcu_barrier(); // Wait for task_struct free, avoid OOM. 2728 for (i = 0; i < read_exit_delay; i++) { 2729 schedule_timeout_uninterruptible(HZ); 2730 if (READ_ONCE(read_exit_child_stop)) 2731 break; 2732 } 2733 if (!READ_ONCE(read_exit_child_stop)) 2734 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of episode"); 2735 count = 0; 2736 } 2737 if (READ_ONCE(read_exit_child_stop)) 2738 break; 2739 // Spawn child. 2740 tsp = kthread_run(rcu_torture_read_exit_child, 2741 &trs, "%s", 2742 "rcu_torture_read_exit_child"); 2743 if (IS_ERR(tsp)) { 2744 VERBOSE_TOROUT_ERRSTRING("out of memory"); 2745 errexit = true; 2746 tsp = NULL; 2747 break; 2748 } 2749 cond_resched(); 2750 kthread_stop(tsp); 2751 n_read_exits ++; 2752 stutter_wait("rcu_torture_read_exit"); 2753 } while (!errexit && !READ_ONCE(read_exit_child_stop)); 2754 2755 // Clean up and exit. 2756 smp_store_release(&read_exit_child_stopped, true); // After reaping. 2757 smp_mb(); // Store before wakeup. 2758 wake_up(&read_exit_wq); 2759 while (!torture_must_stop()) 2760 schedule_timeout_uninterruptible(1); 2761 torture_kthread_stopping("rcu_torture_read_exit"); 2762 return 0; 2763 } 2764 2765 static int rcu_torture_read_exit_init(void) 2766 { 2767 if (read_exit_burst <= 0) 2768 return 0; 2769 init_waitqueue_head(&read_exit_wq); 2770 read_exit_child_stop = false; 2771 read_exit_child_stopped = false; 2772 return torture_create_kthread(rcu_torture_read_exit, NULL, 2773 read_exit_task); 2774 } 2775 2776 static void rcu_torture_read_exit_cleanup(void) 2777 { 2778 if (!read_exit_task) 2779 return; 2780 WRITE_ONCE(read_exit_child_stop, true); 2781 smp_mb(); // Above write before wait. 2782 wait_event(read_exit_wq, smp_load_acquire(&read_exit_child_stopped)); 2783 torture_stop_kthread(rcutorture_read_exit, read_exit_task); 2784 } 2785 2786 static enum cpuhp_state rcutor_hp; 2787 2788 static void 2789 rcu_torture_cleanup(void) 2790 { 2791 int firsttime; 2792 int flags = 0; 2793 unsigned long gp_seq = 0; 2794 int i; 2795 2796 if (torture_cleanup_begin()) { 2797 if (cur_ops->cb_barrier != NULL) 2798 cur_ops->cb_barrier(); 2799 return; 2800 } 2801 if (!cur_ops) { 2802 torture_cleanup_end(); 2803 return; 2804 } 2805 2806 if (cur_ops->gp_kthread_dbg) 2807 cur_ops->gp_kthread_dbg(); 2808 rcu_torture_read_exit_cleanup(); 2809 rcu_torture_barrier_cleanup(); 2810 rcu_torture_fwd_prog_cleanup(); 2811 torture_stop_kthread(rcu_torture_stall, stall_task); 2812 torture_stop_kthread(rcu_torture_writer, writer_task); 2813 2814 if (nocb_tasks) { 2815 for (i = 0; i < nrealnocbers; i++) 2816 torture_stop_kthread(rcu_nocb_toggle, nocb_tasks[i]); 2817 kfree(nocb_tasks); 2818 nocb_tasks = NULL; 2819 } 2820 2821 if (reader_tasks) { 2822 for (i = 0; i < nrealreaders; i++) 2823 torture_stop_kthread(rcu_torture_reader, 2824 reader_tasks[i]); 2825 kfree(reader_tasks); 2826 reader_tasks = NULL; 2827 } 2828 kfree(rcu_torture_reader_mbchk); 2829 rcu_torture_reader_mbchk = NULL; 2830 2831 if (fakewriter_tasks) { 2832 for (i = 0; i < nfakewriters; i++) 2833 torture_stop_kthread(rcu_torture_fakewriter, 2834 fakewriter_tasks[i]); 2835 kfree(fakewriter_tasks); 2836 fakewriter_tasks = NULL; 2837 } 2838 2839 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq); 2840 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq); 2841 pr_alert("%s: End-test grace-period state: g%ld f%#x total-gps=%ld\n", 2842 cur_ops->name, (long)gp_seq, flags, 2843 rcutorture_seq_diff(gp_seq, start_gp_seq)); 2844 torture_stop_kthread(rcu_torture_stats, stats_task); 2845 torture_stop_kthread(rcu_torture_fqs, fqs_task); 2846 if (rcu_torture_can_boost() && rcutor_hp >= 0) 2847 cpuhp_remove_state(rcutor_hp); 2848 2849 /* 2850 * Wait for all RCU callbacks to fire, then do torture-type-specific 2851 * cleanup operations. 2852 */ 2853 if (cur_ops->cb_barrier != NULL) 2854 cur_ops->cb_barrier(); 2855 if (cur_ops->cleanup != NULL) 2856 cur_ops->cleanup(); 2857 2858 rcu_torture_mem_dump_obj(); 2859 2860 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */ 2861 2862 if (err_segs_recorded) { 2863 pr_alert("Failure/close-call rcutorture reader segments:\n"); 2864 if (rt_read_nsegs == 0) 2865 pr_alert("\t: No segments recorded!!!\n"); 2866 firsttime = 1; 2867 for (i = 0; i < rt_read_nsegs; i++) { 2868 pr_alert("\t%d: %#x ", i, err_segs[i].rt_readstate); 2869 if (err_segs[i].rt_delay_jiffies != 0) { 2870 pr_cont("%s%ldjiffies", firsttime ? "" : "+", 2871 err_segs[i].rt_delay_jiffies); 2872 firsttime = 0; 2873 } 2874 if (err_segs[i].rt_delay_ms != 0) { 2875 pr_cont("%s%ldms", firsttime ? "" : "+", 2876 err_segs[i].rt_delay_ms); 2877 firsttime = 0; 2878 } 2879 if (err_segs[i].rt_delay_us != 0) { 2880 pr_cont("%s%ldus", firsttime ? "" : "+", 2881 err_segs[i].rt_delay_us); 2882 firsttime = 0; 2883 } 2884 pr_cont("%s\n", 2885 err_segs[i].rt_preempted ? "preempted" : ""); 2886 2887 } 2888 } 2889 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error) 2890 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE"); 2891 else if (torture_onoff_failures()) 2892 rcu_torture_print_module_parms(cur_ops, 2893 "End of test: RCU_HOTPLUG"); 2894 else 2895 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS"); 2896 torture_cleanup_end(); 2897 } 2898 2899 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD 2900 static void rcu_torture_leak_cb(struct rcu_head *rhp) 2901 { 2902 } 2903 2904 static void rcu_torture_err_cb(struct rcu_head *rhp) 2905 { 2906 /* 2907 * This -might- happen due to race conditions, but is unlikely. 2908 * The scenario that leads to this happening is that the 2909 * first of the pair of duplicate callbacks is queued, 2910 * someone else starts a grace period that includes that 2911 * callback, then the second of the pair must wait for the 2912 * next grace period. Unlikely, but can happen. If it 2913 * does happen, the debug-objects subsystem won't have splatted. 2914 */ 2915 pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME); 2916 } 2917 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 2918 2919 /* 2920 * Verify that double-free causes debug-objects to complain, but only 2921 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test 2922 * cannot be carried out. 2923 */ 2924 static void rcu_test_debug_objects(void) 2925 { 2926 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD 2927 struct rcu_head rh1; 2928 struct rcu_head rh2; 2929 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_KERNEL); 2930 2931 init_rcu_head_on_stack(&rh1); 2932 init_rcu_head_on_stack(&rh2); 2933 pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME); 2934 2935 /* Try to queue the rh2 pair of callbacks for the same grace period. */ 2936 preempt_disable(); /* Prevent preemption from interrupting test. */ 2937 rcu_read_lock(); /* Make it impossible to finish a grace period. */ 2938 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */ 2939 local_irq_disable(); /* Make it harder to start a new grace period. */ 2940 call_rcu(&rh2, rcu_torture_leak_cb); 2941 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */ 2942 if (rhp) { 2943 call_rcu(rhp, rcu_torture_leak_cb); 2944 call_rcu(rhp, rcu_torture_err_cb); /* Another duplicate callback. */ 2945 } 2946 local_irq_enable(); 2947 rcu_read_unlock(); 2948 preempt_enable(); 2949 2950 /* Wait for them all to get done so we can safely return. */ 2951 rcu_barrier(); 2952 pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME); 2953 destroy_rcu_head_on_stack(&rh1); 2954 destroy_rcu_head_on_stack(&rh2); 2955 #else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 2956 pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME); 2957 #endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 2958 } 2959 2960 static void rcutorture_sync(void) 2961 { 2962 static unsigned long n; 2963 2964 if (cur_ops->sync && !(++n & 0xfff)) 2965 cur_ops->sync(); 2966 } 2967 2968 static int __init 2969 rcu_torture_init(void) 2970 { 2971 long i; 2972 int cpu; 2973 int firsterr = 0; 2974 int flags = 0; 2975 unsigned long gp_seq = 0; 2976 static struct rcu_torture_ops *torture_ops[] = { 2977 &rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops, 2978 &busted_srcud_ops, &tasks_ops, &tasks_rude_ops, 2979 &tasks_tracing_ops, &trivial_ops, 2980 }; 2981 2982 if (!torture_init_begin(torture_type, verbose)) 2983 return -EBUSY; 2984 2985 /* Process args and tell the world that the torturer is on the job. */ 2986 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) { 2987 cur_ops = torture_ops[i]; 2988 if (strcmp(torture_type, cur_ops->name) == 0) 2989 break; 2990 } 2991 if (i == ARRAY_SIZE(torture_ops)) { 2992 pr_alert("rcu-torture: invalid torture type: \"%s\"\n", 2993 torture_type); 2994 pr_alert("rcu-torture types:"); 2995 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) 2996 pr_cont(" %s", torture_ops[i]->name); 2997 pr_cont("\n"); 2998 firsterr = -EINVAL; 2999 cur_ops = NULL; 3000 goto unwind; 3001 } 3002 if (cur_ops->fqs == NULL && fqs_duration != 0) { 3003 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n"); 3004 fqs_duration = 0; 3005 } 3006 if (cur_ops->init) 3007 cur_ops->init(); 3008 3009 if (nreaders >= 0) { 3010 nrealreaders = nreaders; 3011 } else { 3012 nrealreaders = num_online_cpus() - 2 - nreaders; 3013 if (nrealreaders <= 0) 3014 nrealreaders = 1; 3015 } 3016 rcu_torture_print_module_parms(cur_ops, "Start of test"); 3017 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq); 3018 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq); 3019 start_gp_seq = gp_seq; 3020 pr_alert("%s: Start-test grace-period state: g%ld f%#x\n", 3021 cur_ops->name, (long)gp_seq, flags); 3022 3023 /* Set up the freelist. */ 3024 3025 INIT_LIST_HEAD(&rcu_torture_freelist); 3026 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) { 3027 rcu_tortures[i].rtort_mbtest = 0; 3028 list_add_tail(&rcu_tortures[i].rtort_free, 3029 &rcu_torture_freelist); 3030 } 3031 3032 /* Initialize the statistics so that each run gets its own numbers. */ 3033 3034 rcu_torture_current = NULL; 3035 rcu_torture_current_version = 0; 3036 atomic_set(&n_rcu_torture_alloc, 0); 3037 atomic_set(&n_rcu_torture_alloc_fail, 0); 3038 atomic_set(&n_rcu_torture_free, 0); 3039 atomic_set(&n_rcu_torture_mberror, 0); 3040 atomic_set(&n_rcu_torture_mbchk_fail, 0); 3041 atomic_set(&n_rcu_torture_mbchk_tries, 0); 3042 atomic_set(&n_rcu_torture_error, 0); 3043 n_rcu_torture_barrier_error = 0; 3044 n_rcu_torture_boost_ktrerror = 0; 3045 n_rcu_torture_boost_rterror = 0; 3046 n_rcu_torture_boost_failure = 0; 3047 n_rcu_torture_boosts = 0; 3048 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 3049 atomic_set(&rcu_torture_wcount[i], 0); 3050 for_each_possible_cpu(cpu) { 3051 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 3052 per_cpu(rcu_torture_count, cpu)[i] = 0; 3053 per_cpu(rcu_torture_batch, cpu)[i] = 0; 3054 } 3055 } 3056 err_segs_recorded = 0; 3057 rt_read_nsegs = 0; 3058 3059 /* Start up the kthreads. */ 3060 3061 rcu_torture_write_types(); 3062 firsterr = torture_create_kthread(rcu_torture_writer, NULL, 3063 writer_task); 3064 if (torture_init_error(firsterr)) 3065 goto unwind; 3066 if (nfakewriters > 0) { 3067 fakewriter_tasks = kcalloc(nfakewriters, 3068 sizeof(fakewriter_tasks[0]), 3069 GFP_KERNEL); 3070 if (fakewriter_tasks == NULL) { 3071 VERBOSE_TOROUT_ERRSTRING("out of memory"); 3072 firsterr = -ENOMEM; 3073 goto unwind; 3074 } 3075 } 3076 for (i = 0; i < nfakewriters; i++) { 3077 firsterr = torture_create_kthread(rcu_torture_fakewriter, 3078 NULL, fakewriter_tasks[i]); 3079 if (torture_init_error(firsterr)) 3080 goto unwind; 3081 } 3082 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]), 3083 GFP_KERNEL); 3084 rcu_torture_reader_mbchk = kcalloc(nrealreaders, sizeof(*rcu_torture_reader_mbchk), 3085 GFP_KERNEL); 3086 if (!reader_tasks || !rcu_torture_reader_mbchk) { 3087 VERBOSE_TOROUT_ERRSTRING("out of memory"); 3088 firsterr = -ENOMEM; 3089 goto unwind; 3090 } 3091 for (i = 0; i < nrealreaders; i++) { 3092 rcu_torture_reader_mbchk[i].rtc_chkrdr = -1; 3093 firsterr = torture_create_kthread(rcu_torture_reader, (void *)i, 3094 reader_tasks[i]); 3095 if (torture_init_error(firsterr)) 3096 goto unwind; 3097 } 3098 nrealnocbers = nocbs_nthreads; 3099 if (WARN_ON(nrealnocbers < 0)) 3100 nrealnocbers = 1; 3101 if (WARN_ON(nocbs_toggle < 0)) 3102 nocbs_toggle = HZ; 3103 if (nrealnocbers > 0) { 3104 nocb_tasks = kcalloc(nrealnocbers, sizeof(nocb_tasks[0]), GFP_KERNEL); 3105 if (nocb_tasks == NULL) { 3106 VERBOSE_TOROUT_ERRSTRING("out of memory"); 3107 firsterr = -ENOMEM; 3108 goto unwind; 3109 } 3110 } else { 3111 nocb_tasks = NULL; 3112 } 3113 for (i = 0; i < nrealnocbers; i++) { 3114 firsterr = torture_create_kthread(rcu_nocb_toggle, NULL, nocb_tasks[i]); 3115 if (torture_init_error(firsterr)) 3116 goto unwind; 3117 } 3118 if (stat_interval > 0) { 3119 firsterr = torture_create_kthread(rcu_torture_stats, NULL, 3120 stats_task); 3121 if (torture_init_error(firsterr)) 3122 goto unwind; 3123 } 3124 if (test_no_idle_hz && shuffle_interval > 0) { 3125 firsterr = torture_shuffle_init(shuffle_interval * HZ); 3126 if (torture_init_error(firsterr)) 3127 goto unwind; 3128 } 3129 if (stutter < 0) 3130 stutter = 0; 3131 if (stutter) { 3132 int t; 3133 3134 t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ; 3135 firsterr = torture_stutter_init(stutter * HZ, t); 3136 if (torture_init_error(firsterr)) 3137 goto unwind; 3138 } 3139 if (fqs_duration < 0) 3140 fqs_duration = 0; 3141 if (fqs_duration) { 3142 /* Create the fqs thread */ 3143 firsterr = torture_create_kthread(rcu_torture_fqs, NULL, 3144 fqs_task); 3145 if (torture_init_error(firsterr)) 3146 goto unwind; 3147 } 3148 if (test_boost_interval < 1) 3149 test_boost_interval = 1; 3150 if (test_boost_duration < 2) 3151 test_boost_duration = 2; 3152 if (rcu_torture_can_boost()) { 3153 3154 boost_starttime = jiffies + test_boost_interval * HZ; 3155 3156 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE", 3157 rcutorture_booster_init, 3158 rcutorture_booster_cleanup); 3159 rcutor_hp = firsterr; 3160 if (torture_init_error(firsterr)) 3161 goto unwind; 3162 3163 // Testing RCU priority boosting requires rcutorture do 3164 // some serious abuse. Counter this by running ksoftirqd 3165 // at higher priority. 3166 if (IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)) { 3167 for_each_online_cpu(cpu) { 3168 struct sched_param sp; 3169 struct task_struct *t; 3170 3171 t = per_cpu(ksoftirqd, cpu); 3172 WARN_ON_ONCE(!t); 3173 sp.sched_priority = 2; 3174 sched_setscheduler_nocheck(t, SCHED_FIFO, &sp); 3175 } 3176 } 3177 } 3178 shutdown_jiffies = jiffies + shutdown_secs * HZ; 3179 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup); 3180 if (torture_init_error(firsterr)) 3181 goto unwind; 3182 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval, 3183 rcutorture_sync); 3184 if (torture_init_error(firsterr)) 3185 goto unwind; 3186 firsterr = rcu_torture_stall_init(); 3187 if (torture_init_error(firsterr)) 3188 goto unwind; 3189 firsterr = rcu_torture_fwd_prog_init(); 3190 if (torture_init_error(firsterr)) 3191 goto unwind; 3192 firsterr = rcu_torture_barrier_init(); 3193 if (torture_init_error(firsterr)) 3194 goto unwind; 3195 firsterr = rcu_torture_read_exit_init(); 3196 if (torture_init_error(firsterr)) 3197 goto unwind; 3198 if (object_debug) 3199 rcu_test_debug_objects(); 3200 torture_init_end(); 3201 return 0; 3202 3203 unwind: 3204 torture_init_end(); 3205 rcu_torture_cleanup(); 3206 if (shutdown_secs) { 3207 WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST)); 3208 kernel_power_off(); 3209 } 3210 return firsterr; 3211 } 3212 3213 module_init(rcu_torture_init); 3214 module_exit(rcu_torture_cleanup); 3215