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 #include <linux/nmi.h> 50 51 #include "rcu.h" 52 53 MODULE_LICENSE("GPL"); 54 MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com> and Josh Triplett <josh@joshtriplett.org>"); 55 56 /* Bits for ->extendables field, extendables param, and related definitions. */ 57 #define RCUTORTURE_RDR_SHIFT_1 8 /* Put SRCU index in upper bits. */ 58 #define RCUTORTURE_RDR_MASK_1 (1 << RCUTORTURE_RDR_SHIFT_1) 59 #define RCUTORTURE_RDR_SHIFT_2 9 /* Put SRCU index in upper bits. */ 60 #define RCUTORTURE_RDR_MASK_2 (1 << RCUTORTURE_RDR_SHIFT_2) 61 #define RCUTORTURE_RDR_BH 0x01 /* Extend readers by disabling bh. */ 62 #define RCUTORTURE_RDR_IRQ 0x02 /* ... disabling interrupts. */ 63 #define RCUTORTURE_RDR_PREEMPT 0x04 /* ... disabling preemption. */ 64 #define RCUTORTURE_RDR_RBH 0x08 /* ... rcu_read_lock_bh(). */ 65 #define RCUTORTURE_RDR_SCHED 0x10 /* ... rcu_read_lock_sched(). */ 66 #define RCUTORTURE_RDR_RCU_1 0x20 /* ... entering another RCU reader. */ 67 #define RCUTORTURE_RDR_RCU_2 0x40 /* ... entering another RCU reader. */ 68 #define RCUTORTURE_RDR_NBITS 7 /* Number of bits defined above. */ 69 #define RCUTORTURE_MAX_EXTEND \ 70 (RCUTORTURE_RDR_BH | RCUTORTURE_RDR_IRQ | RCUTORTURE_RDR_PREEMPT | \ 71 RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED) 72 #define RCUTORTURE_RDR_MAX_LOOPS 0x7 /* Maximum reader extensions. */ 73 /* Must be power of two minus one. */ 74 #define RCUTORTURE_RDR_MAX_SEGS (RCUTORTURE_RDR_MAX_LOOPS + 3) 75 76 torture_param(int, extendables, RCUTORTURE_MAX_EXTEND, 77 "Extend readers by disabling bh (1), irqs (2), or preempt (4)"); 78 torture_param(int, fqs_duration, 0, 79 "Duration of fqs bursts (us), 0 to disable"); 80 torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)"); 81 torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)"); 82 torture_param(int, fwd_progress, 1, "Test grace-period forward progress"); 83 torture_param(int, fwd_progress_div, 4, "Fraction of CPU stall to wait"); 84 torture_param(int, fwd_progress_holdoff, 60, 85 "Time between forward-progress tests (s)"); 86 torture_param(bool, fwd_progress_need_resched, 1, 87 "Hide cond_resched() behind need_resched()"); 88 torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives"); 89 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives"); 90 torture_param(bool, gp_normal, false, 91 "Use normal (non-expedited) GP wait primitives"); 92 torture_param(bool, gp_poll, false, "Use polling GP wait primitives"); 93 torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives"); 94 torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers"); 95 torture_param(int, leakpointer, 0, "Leak pointer dereferences from readers"); 96 torture_param(int, n_barrier_cbs, 0, 97 "# of callbacks/kthreads for barrier testing"); 98 torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads"); 99 torture_param(int, nreaders, -1, "Number of RCU reader threads"); 100 torture_param(int, object_debug, 0, 101 "Enable debug-object double call_rcu() testing"); 102 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)"); 103 torture_param(int, onoff_interval, 0, 104 "Time between CPU hotplugs (jiffies), 0=disable"); 105 torture_param(int, nocbs_nthreads, 0, "Number of NOCB toggle threads, 0 to disable"); 106 torture_param(int, nocbs_toggle, 1000, "Time between toggling nocb state (ms)"); 107 torture_param(int, read_exit_delay, 13, 108 "Delay between read-then-exit episodes (s)"); 109 torture_param(int, read_exit_burst, 16, 110 "# of read-then-exit bursts per episode, zero to disable"); 111 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles"); 112 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable."); 113 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable."); 114 torture_param(int, stall_cpu_holdoff, 10, 115 "Time to wait before starting stall (s)."); 116 torture_param(bool, stall_no_softlockup, false, 117 "Avoid softlockup warning during cpu stall."); 118 torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling."); 119 torture_param(int, stall_cpu_block, 0, "Sleep while stalling."); 120 torture_param(int, stall_gp_kthread, 0, 121 "Grace-period kthread stall duration (s)."); 122 torture_param(int, stat_interval, 60, 123 "Number of seconds between stats printk()s"); 124 torture_param(int, stutter, 5, "Number of seconds to run/halt test"); 125 torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes."); 126 torture_param(int, test_boost_duration, 4, 127 "Duration of each boost test, seconds."); 128 torture_param(int, test_boost_interval, 7, 129 "Interval between boost tests, seconds."); 130 torture_param(bool, test_no_idle_hz, true, 131 "Test support for tickless idle CPUs"); 132 torture_param(int, verbose, 1, 133 "Enable verbose debugging printk()s"); 134 135 static char *torture_type = "rcu"; 136 module_param(torture_type, charp, 0444); 137 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, srcu, ...)"); 138 139 static int nrealnocbers; 140 static int nrealreaders; 141 static struct task_struct *writer_task; 142 static struct task_struct **fakewriter_tasks; 143 static struct task_struct **reader_tasks; 144 static struct task_struct **nocb_tasks; 145 static struct task_struct *stats_task; 146 static struct task_struct *fqs_task; 147 static struct task_struct *boost_tasks[NR_CPUS]; 148 static struct task_struct *stall_task; 149 static struct task_struct **fwd_prog_tasks; 150 static struct task_struct **barrier_cbs_tasks; 151 static struct task_struct *barrier_task; 152 static struct task_struct *read_exit_task; 153 154 #define RCU_TORTURE_PIPE_LEN 10 155 156 // Mailbox-like structure to check RCU global memory ordering. 157 struct rcu_torture_reader_check { 158 unsigned long rtc_myloops; 159 int rtc_chkrdr; 160 unsigned long rtc_chkloops; 161 int rtc_ready; 162 struct rcu_torture_reader_check *rtc_assigner; 163 } ____cacheline_internodealigned_in_smp; 164 165 // Update-side data structure used to check RCU readers. 166 struct rcu_torture { 167 struct rcu_head rtort_rcu; 168 int rtort_pipe_count; 169 struct list_head rtort_free; 170 int rtort_mbtest; 171 struct rcu_torture_reader_check *rtort_chkp; 172 }; 173 174 static LIST_HEAD(rcu_torture_freelist); 175 static struct rcu_torture __rcu *rcu_torture_current; 176 static unsigned long rcu_torture_current_version; 177 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN]; 178 static DEFINE_SPINLOCK(rcu_torture_lock); 179 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count); 180 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch); 181 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1]; 182 static struct rcu_torture_reader_check *rcu_torture_reader_mbchk; 183 static atomic_t n_rcu_torture_alloc; 184 static atomic_t n_rcu_torture_alloc_fail; 185 static atomic_t n_rcu_torture_free; 186 static atomic_t n_rcu_torture_mberror; 187 static atomic_t n_rcu_torture_mbchk_fail; 188 static atomic_t n_rcu_torture_mbchk_tries; 189 static atomic_t n_rcu_torture_error; 190 static long n_rcu_torture_barrier_error; 191 static long n_rcu_torture_boost_ktrerror; 192 static long n_rcu_torture_boost_rterror; 193 static long n_rcu_torture_boost_failure; 194 static long n_rcu_torture_boosts; 195 static atomic_long_t n_rcu_torture_timers; 196 static long n_barrier_attempts; 197 static long n_barrier_successes; /* did rcu_barrier test succeed? */ 198 static unsigned long n_read_exits; 199 static struct list_head rcu_torture_removed; 200 static unsigned long shutdown_jiffies; 201 static unsigned long start_gp_seq; 202 static atomic_long_t n_nocb_offload; 203 static atomic_long_t n_nocb_deoffload; 204 205 static int rcu_torture_writer_state; 206 #define RTWS_FIXED_DELAY 0 207 #define RTWS_DELAY 1 208 #define RTWS_REPLACE 2 209 #define RTWS_DEF_FREE 3 210 #define RTWS_EXP_SYNC 4 211 #define RTWS_COND_GET 5 212 #define RTWS_COND_SYNC 6 213 #define RTWS_POLL_GET 7 214 #define RTWS_POLL_WAIT 8 215 #define RTWS_SYNC 9 216 #define RTWS_STUTTER 10 217 #define RTWS_STOPPING 11 218 static const char * const rcu_torture_writer_state_names[] = { 219 "RTWS_FIXED_DELAY", 220 "RTWS_DELAY", 221 "RTWS_REPLACE", 222 "RTWS_DEF_FREE", 223 "RTWS_EXP_SYNC", 224 "RTWS_COND_GET", 225 "RTWS_COND_SYNC", 226 "RTWS_POLL_GET", 227 "RTWS_POLL_WAIT", 228 "RTWS_SYNC", 229 "RTWS_STUTTER", 230 "RTWS_STOPPING", 231 }; 232 233 /* Record reader segment types and duration for first failing read. */ 234 struct rt_read_seg { 235 int rt_readstate; 236 unsigned long rt_delay_jiffies; 237 unsigned long rt_delay_ms; 238 unsigned long rt_delay_us; 239 bool rt_preempted; 240 }; 241 static int err_segs_recorded; 242 static struct rt_read_seg err_segs[RCUTORTURE_RDR_MAX_SEGS]; 243 static int rt_read_nsegs; 244 245 static const char *rcu_torture_writer_state_getname(void) 246 { 247 unsigned int i = READ_ONCE(rcu_torture_writer_state); 248 249 if (i >= ARRAY_SIZE(rcu_torture_writer_state_names)) 250 return "???"; 251 return rcu_torture_writer_state_names[i]; 252 } 253 254 #ifdef CONFIG_RCU_TRACE 255 static u64 notrace rcu_trace_clock_local(void) 256 { 257 u64 ts = trace_clock_local(); 258 259 (void)do_div(ts, NSEC_PER_USEC); 260 return ts; 261 } 262 #else /* #ifdef CONFIG_RCU_TRACE */ 263 static u64 notrace rcu_trace_clock_local(void) 264 { 265 return 0ULL; 266 } 267 #endif /* #else #ifdef CONFIG_RCU_TRACE */ 268 269 /* 270 * Stop aggressive CPU-hog tests a bit before the end of the test in order 271 * to avoid interfering with test shutdown. 272 */ 273 static bool shutdown_time_arrived(void) 274 { 275 return shutdown_secs && time_after(jiffies, shutdown_jiffies - 30 * HZ); 276 } 277 278 static unsigned long boost_starttime; /* jiffies of next boost test start. */ 279 static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */ 280 /* and boost task create/destroy. */ 281 static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */ 282 static bool barrier_phase; /* Test phase. */ 283 static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */ 284 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */ 285 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq); 286 287 static atomic_t rcu_fwd_cb_nodelay; /* Short rcu_torture_delay() delays. */ 288 289 /* 290 * Allocate an element from the rcu_tortures pool. 291 */ 292 static struct rcu_torture * 293 rcu_torture_alloc(void) 294 { 295 struct list_head *p; 296 297 spin_lock_bh(&rcu_torture_lock); 298 if (list_empty(&rcu_torture_freelist)) { 299 atomic_inc(&n_rcu_torture_alloc_fail); 300 spin_unlock_bh(&rcu_torture_lock); 301 return NULL; 302 } 303 atomic_inc(&n_rcu_torture_alloc); 304 p = rcu_torture_freelist.next; 305 list_del_init(p); 306 spin_unlock_bh(&rcu_torture_lock); 307 return container_of(p, struct rcu_torture, rtort_free); 308 } 309 310 /* 311 * Free an element to the rcu_tortures pool. 312 */ 313 static void 314 rcu_torture_free(struct rcu_torture *p) 315 { 316 atomic_inc(&n_rcu_torture_free); 317 spin_lock_bh(&rcu_torture_lock); 318 list_add_tail(&p->rtort_free, &rcu_torture_freelist); 319 spin_unlock_bh(&rcu_torture_lock); 320 } 321 322 /* 323 * Operations vector for selecting different types of tests. 324 */ 325 326 struct rcu_torture_ops { 327 int ttype; 328 void (*init)(void); 329 void (*cleanup)(void); 330 int (*readlock)(void); 331 void (*read_delay)(struct torture_random_state *rrsp, 332 struct rt_read_seg *rtrsp); 333 void (*readunlock)(int idx); 334 int (*readlock_held)(void); 335 unsigned long (*get_gp_seq)(void); 336 unsigned long (*gp_diff)(unsigned long new, unsigned long old); 337 void (*deferred_free)(struct rcu_torture *p); 338 void (*sync)(void); 339 void (*exp_sync)(void); 340 unsigned long (*get_gp_state)(void); 341 unsigned long (*start_gp_poll)(void); 342 bool (*poll_gp_state)(unsigned long oldstate); 343 void (*cond_sync)(unsigned long oldstate); 344 call_rcu_func_t call; 345 void (*cb_barrier)(void); 346 void (*fqs)(void); 347 void (*stats)(void); 348 void (*gp_kthread_dbg)(void); 349 bool (*check_boost_failed)(unsigned long gp_state, int *cpup); 350 int (*stall_dur)(void); 351 long cbflood_max; 352 int irq_capable; 353 int can_boost; 354 int extendables; 355 int slow_gps; 356 int no_pi_lock; 357 const char *name; 358 }; 359 360 static struct rcu_torture_ops *cur_ops; 361 362 /* 363 * Definitions for rcu torture testing. 364 */ 365 366 static int torture_readlock_not_held(void) 367 { 368 return rcu_read_lock_bh_held() || rcu_read_lock_sched_held(); 369 } 370 371 static int rcu_torture_read_lock(void) __acquires(RCU) 372 { 373 rcu_read_lock(); 374 return 0; 375 } 376 377 static void 378 rcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp) 379 { 380 unsigned long started; 381 unsigned long completed; 382 const unsigned long shortdelay_us = 200; 383 unsigned long longdelay_ms = 300; 384 unsigned long long ts; 385 386 /* We want a short delay sometimes to make a reader delay the grace 387 * period, and we want a long delay occasionally to trigger 388 * force_quiescent_state. */ 389 390 if (!atomic_read(&rcu_fwd_cb_nodelay) && 391 !(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) { 392 started = cur_ops->get_gp_seq(); 393 ts = rcu_trace_clock_local(); 394 if (preempt_count() & (SOFTIRQ_MASK | HARDIRQ_MASK)) 395 longdelay_ms = 5; /* Avoid triggering BH limits. */ 396 mdelay(longdelay_ms); 397 rtrsp->rt_delay_ms = longdelay_ms; 398 completed = cur_ops->get_gp_seq(); 399 do_trace_rcu_torture_read(cur_ops->name, NULL, ts, 400 started, completed); 401 } 402 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) { 403 udelay(shortdelay_us); 404 rtrsp->rt_delay_us = shortdelay_us; 405 } 406 if (!preempt_count() && 407 !(torture_random(rrsp) % (nrealreaders * 500))) { 408 torture_preempt_schedule(); /* QS only if preemptible. */ 409 rtrsp->rt_preempted = true; 410 } 411 } 412 413 static void rcu_torture_read_unlock(int idx) __releases(RCU) 414 { 415 rcu_read_unlock(); 416 } 417 418 /* 419 * Update callback in the pipe. This should be invoked after a grace period. 420 */ 421 static bool 422 rcu_torture_pipe_update_one(struct rcu_torture *rp) 423 { 424 int i; 425 struct rcu_torture_reader_check *rtrcp = READ_ONCE(rp->rtort_chkp); 426 427 if (rtrcp) { 428 WRITE_ONCE(rp->rtort_chkp, NULL); 429 smp_store_release(&rtrcp->rtc_ready, 1); // Pair with smp_load_acquire(). 430 } 431 i = READ_ONCE(rp->rtort_pipe_count); 432 if (i > RCU_TORTURE_PIPE_LEN) 433 i = RCU_TORTURE_PIPE_LEN; 434 atomic_inc(&rcu_torture_wcount[i]); 435 WRITE_ONCE(rp->rtort_pipe_count, i + 1); 436 if (rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) { 437 rp->rtort_mbtest = 0; 438 return true; 439 } 440 return false; 441 } 442 443 /* 444 * Update all callbacks in the pipe. Suitable for synchronous grace-period 445 * primitives. 446 */ 447 static void 448 rcu_torture_pipe_update(struct rcu_torture *old_rp) 449 { 450 struct rcu_torture *rp; 451 struct rcu_torture *rp1; 452 453 if (old_rp) 454 list_add(&old_rp->rtort_free, &rcu_torture_removed); 455 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) { 456 if (rcu_torture_pipe_update_one(rp)) { 457 list_del(&rp->rtort_free); 458 rcu_torture_free(rp); 459 } 460 } 461 } 462 463 static void 464 rcu_torture_cb(struct rcu_head *p) 465 { 466 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu); 467 468 if (torture_must_stop_irq()) { 469 /* Test is ending, just drop callbacks on the floor. */ 470 /* The next initialization will pick up the pieces. */ 471 return; 472 } 473 if (rcu_torture_pipe_update_one(rp)) 474 rcu_torture_free(rp); 475 else 476 cur_ops->deferred_free(rp); 477 } 478 479 static unsigned long rcu_no_completed(void) 480 { 481 return 0; 482 } 483 484 static void rcu_torture_deferred_free(struct rcu_torture *p) 485 { 486 call_rcu(&p->rtort_rcu, rcu_torture_cb); 487 } 488 489 static void rcu_sync_torture_init(void) 490 { 491 INIT_LIST_HEAD(&rcu_torture_removed); 492 } 493 494 static struct rcu_torture_ops rcu_ops = { 495 .ttype = RCU_FLAVOR, 496 .init = rcu_sync_torture_init, 497 .readlock = rcu_torture_read_lock, 498 .read_delay = rcu_read_delay, 499 .readunlock = rcu_torture_read_unlock, 500 .readlock_held = torture_readlock_not_held, 501 .get_gp_seq = rcu_get_gp_seq, 502 .gp_diff = rcu_seq_diff, 503 .deferred_free = rcu_torture_deferred_free, 504 .sync = synchronize_rcu, 505 .exp_sync = synchronize_rcu_expedited, 506 .get_gp_state = get_state_synchronize_rcu, 507 .start_gp_poll = start_poll_synchronize_rcu, 508 .poll_gp_state = poll_state_synchronize_rcu, 509 .cond_sync = cond_synchronize_rcu, 510 .call = call_rcu, 511 .cb_barrier = rcu_barrier, 512 .fqs = rcu_force_quiescent_state, 513 .stats = NULL, 514 .gp_kthread_dbg = show_rcu_gp_kthreads, 515 .check_boost_failed = rcu_check_boost_fail, 516 .stall_dur = rcu_jiffies_till_stall_check, 517 .irq_capable = 1, 518 .can_boost = IS_ENABLED(CONFIG_RCU_BOOST), 519 .extendables = RCUTORTURE_MAX_EXTEND, 520 .name = "rcu" 521 }; 522 523 /* 524 * Don't even think about trying any of these in real life!!! 525 * The names includes "busted", and they really means it! 526 * The only purpose of these functions is to provide a buggy RCU 527 * implementation to make sure that rcutorture correctly emits 528 * buggy-RCU error messages. 529 */ 530 static void rcu_busted_torture_deferred_free(struct rcu_torture *p) 531 { 532 /* This is a deliberate bug for testing purposes only! */ 533 rcu_torture_cb(&p->rtort_rcu); 534 } 535 536 static void synchronize_rcu_busted(void) 537 { 538 /* This is a deliberate bug for testing purposes only! */ 539 } 540 541 static void 542 call_rcu_busted(struct rcu_head *head, rcu_callback_t func) 543 { 544 /* This is a deliberate bug for testing purposes only! */ 545 func(head); 546 } 547 548 static struct rcu_torture_ops rcu_busted_ops = { 549 .ttype = INVALID_RCU_FLAVOR, 550 .init = rcu_sync_torture_init, 551 .readlock = rcu_torture_read_lock, 552 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 553 .readunlock = rcu_torture_read_unlock, 554 .readlock_held = torture_readlock_not_held, 555 .get_gp_seq = rcu_no_completed, 556 .deferred_free = rcu_busted_torture_deferred_free, 557 .sync = synchronize_rcu_busted, 558 .exp_sync = synchronize_rcu_busted, 559 .call = call_rcu_busted, 560 .cb_barrier = NULL, 561 .fqs = NULL, 562 .stats = NULL, 563 .irq_capable = 1, 564 .name = "busted" 565 }; 566 567 /* 568 * Definitions for srcu torture testing. 569 */ 570 571 DEFINE_STATIC_SRCU(srcu_ctl); 572 static struct srcu_struct srcu_ctld; 573 static struct srcu_struct *srcu_ctlp = &srcu_ctl; 574 575 static int srcu_torture_read_lock(void) __acquires(srcu_ctlp) 576 { 577 return srcu_read_lock(srcu_ctlp); 578 } 579 580 static void 581 srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp) 582 { 583 long delay; 584 const long uspertick = 1000000 / HZ; 585 const long longdelay = 10; 586 587 /* We want there to be long-running readers, but not all the time. */ 588 589 delay = torture_random(rrsp) % 590 (nrealreaders * 2 * longdelay * uspertick); 591 if (!delay && in_task()) { 592 schedule_timeout_interruptible(longdelay); 593 rtrsp->rt_delay_jiffies = longdelay; 594 } else { 595 rcu_read_delay(rrsp, rtrsp); 596 } 597 } 598 599 static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp) 600 { 601 srcu_read_unlock(srcu_ctlp, idx); 602 } 603 604 static int torture_srcu_read_lock_held(void) 605 { 606 return srcu_read_lock_held(srcu_ctlp); 607 } 608 609 static unsigned long srcu_torture_completed(void) 610 { 611 return srcu_batches_completed(srcu_ctlp); 612 } 613 614 static void srcu_torture_deferred_free(struct rcu_torture *rp) 615 { 616 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb); 617 } 618 619 static void srcu_torture_synchronize(void) 620 { 621 synchronize_srcu(srcu_ctlp); 622 } 623 624 static unsigned long srcu_torture_get_gp_state(void) 625 { 626 return get_state_synchronize_srcu(srcu_ctlp); 627 } 628 629 static unsigned long srcu_torture_start_gp_poll(void) 630 { 631 return start_poll_synchronize_srcu(srcu_ctlp); 632 } 633 634 static bool srcu_torture_poll_gp_state(unsigned long oldstate) 635 { 636 return poll_state_synchronize_srcu(srcu_ctlp, oldstate); 637 } 638 639 static void srcu_torture_call(struct rcu_head *head, 640 rcu_callback_t func) 641 { 642 call_srcu(srcu_ctlp, head, func); 643 } 644 645 static void srcu_torture_barrier(void) 646 { 647 srcu_barrier(srcu_ctlp); 648 } 649 650 static void srcu_torture_stats(void) 651 { 652 srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG); 653 } 654 655 static void srcu_torture_synchronize_expedited(void) 656 { 657 synchronize_srcu_expedited(srcu_ctlp); 658 } 659 660 static struct rcu_torture_ops srcu_ops = { 661 .ttype = SRCU_FLAVOR, 662 .init = rcu_sync_torture_init, 663 .readlock = srcu_torture_read_lock, 664 .read_delay = srcu_read_delay, 665 .readunlock = srcu_torture_read_unlock, 666 .readlock_held = torture_srcu_read_lock_held, 667 .get_gp_seq = srcu_torture_completed, 668 .deferred_free = srcu_torture_deferred_free, 669 .sync = srcu_torture_synchronize, 670 .exp_sync = srcu_torture_synchronize_expedited, 671 .get_gp_state = srcu_torture_get_gp_state, 672 .start_gp_poll = srcu_torture_start_gp_poll, 673 .poll_gp_state = srcu_torture_poll_gp_state, 674 .call = srcu_torture_call, 675 .cb_barrier = srcu_torture_barrier, 676 .stats = srcu_torture_stats, 677 .cbflood_max = 50000, 678 .irq_capable = 1, 679 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU), 680 .name = "srcu" 681 }; 682 683 static void srcu_torture_init(void) 684 { 685 rcu_sync_torture_init(); 686 WARN_ON(init_srcu_struct(&srcu_ctld)); 687 srcu_ctlp = &srcu_ctld; 688 } 689 690 static void srcu_torture_cleanup(void) 691 { 692 cleanup_srcu_struct(&srcu_ctld); 693 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */ 694 } 695 696 /* As above, but dynamically allocated. */ 697 static struct rcu_torture_ops srcud_ops = { 698 .ttype = SRCU_FLAVOR, 699 .init = srcu_torture_init, 700 .cleanup = srcu_torture_cleanup, 701 .readlock = srcu_torture_read_lock, 702 .read_delay = srcu_read_delay, 703 .readunlock = srcu_torture_read_unlock, 704 .readlock_held = torture_srcu_read_lock_held, 705 .get_gp_seq = srcu_torture_completed, 706 .deferred_free = srcu_torture_deferred_free, 707 .sync = srcu_torture_synchronize, 708 .exp_sync = srcu_torture_synchronize_expedited, 709 .call = srcu_torture_call, 710 .cb_barrier = srcu_torture_barrier, 711 .stats = srcu_torture_stats, 712 .cbflood_max = 50000, 713 .irq_capable = 1, 714 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU), 715 .name = "srcud" 716 }; 717 718 /* As above, but broken due to inappropriate reader extension. */ 719 static struct rcu_torture_ops busted_srcud_ops = { 720 .ttype = SRCU_FLAVOR, 721 .init = srcu_torture_init, 722 .cleanup = srcu_torture_cleanup, 723 .readlock = srcu_torture_read_lock, 724 .read_delay = rcu_read_delay, 725 .readunlock = srcu_torture_read_unlock, 726 .readlock_held = torture_srcu_read_lock_held, 727 .get_gp_seq = srcu_torture_completed, 728 .deferred_free = srcu_torture_deferred_free, 729 .sync = srcu_torture_synchronize, 730 .exp_sync = srcu_torture_synchronize_expedited, 731 .call = srcu_torture_call, 732 .cb_barrier = srcu_torture_barrier, 733 .stats = srcu_torture_stats, 734 .irq_capable = 1, 735 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU), 736 .extendables = RCUTORTURE_MAX_EXTEND, 737 .name = "busted_srcud" 738 }; 739 740 /* 741 * Definitions for trivial CONFIG_PREEMPT=n-only torture testing. 742 * This implementation does not necessarily work well with CPU hotplug. 743 */ 744 745 static void synchronize_rcu_trivial(void) 746 { 747 int cpu; 748 749 for_each_online_cpu(cpu) { 750 rcutorture_sched_setaffinity(current->pid, cpumask_of(cpu)); 751 WARN_ON_ONCE(raw_smp_processor_id() != cpu); 752 } 753 } 754 755 static int rcu_torture_read_lock_trivial(void) __acquires(RCU) 756 { 757 preempt_disable(); 758 return 0; 759 } 760 761 static void rcu_torture_read_unlock_trivial(int idx) __releases(RCU) 762 { 763 preempt_enable(); 764 } 765 766 static struct rcu_torture_ops trivial_ops = { 767 .ttype = RCU_TRIVIAL_FLAVOR, 768 .init = rcu_sync_torture_init, 769 .readlock = rcu_torture_read_lock_trivial, 770 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 771 .readunlock = rcu_torture_read_unlock_trivial, 772 .readlock_held = torture_readlock_not_held, 773 .get_gp_seq = rcu_no_completed, 774 .sync = synchronize_rcu_trivial, 775 .exp_sync = synchronize_rcu_trivial, 776 .fqs = NULL, 777 .stats = NULL, 778 .irq_capable = 1, 779 .name = "trivial" 780 }; 781 782 #ifdef CONFIG_TASKS_RCU 783 784 /* 785 * Definitions for RCU-tasks torture testing. 786 */ 787 788 static int tasks_torture_read_lock(void) 789 { 790 return 0; 791 } 792 793 static void tasks_torture_read_unlock(int idx) 794 { 795 } 796 797 static void rcu_tasks_torture_deferred_free(struct rcu_torture *p) 798 { 799 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb); 800 } 801 802 static void synchronize_rcu_mult_test(void) 803 { 804 synchronize_rcu_mult(call_rcu_tasks, call_rcu); 805 } 806 807 static struct rcu_torture_ops tasks_ops = { 808 .ttype = RCU_TASKS_FLAVOR, 809 .init = rcu_sync_torture_init, 810 .readlock = tasks_torture_read_lock, 811 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 812 .readunlock = tasks_torture_read_unlock, 813 .get_gp_seq = rcu_no_completed, 814 .deferred_free = rcu_tasks_torture_deferred_free, 815 .sync = synchronize_rcu_tasks, 816 .exp_sync = synchronize_rcu_mult_test, 817 .call = call_rcu_tasks, 818 .cb_barrier = rcu_barrier_tasks, 819 .gp_kthread_dbg = show_rcu_tasks_classic_gp_kthread, 820 .fqs = NULL, 821 .stats = NULL, 822 .irq_capable = 1, 823 .slow_gps = 1, 824 .name = "tasks" 825 }; 826 827 #define TASKS_OPS &tasks_ops, 828 829 #else // #ifdef CONFIG_TASKS_RCU 830 831 #define TASKS_OPS 832 833 #endif // #else #ifdef CONFIG_TASKS_RCU 834 835 836 #ifdef CONFIG_TASKS_RUDE_RCU 837 838 /* 839 * Definitions for rude RCU-tasks torture testing. 840 */ 841 842 static void rcu_tasks_rude_torture_deferred_free(struct rcu_torture *p) 843 { 844 call_rcu_tasks_rude(&p->rtort_rcu, rcu_torture_cb); 845 } 846 847 static struct rcu_torture_ops tasks_rude_ops = { 848 .ttype = RCU_TASKS_RUDE_FLAVOR, 849 .init = rcu_sync_torture_init, 850 .readlock = rcu_torture_read_lock_trivial, 851 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 852 .readunlock = rcu_torture_read_unlock_trivial, 853 .get_gp_seq = rcu_no_completed, 854 .deferred_free = rcu_tasks_rude_torture_deferred_free, 855 .sync = synchronize_rcu_tasks_rude, 856 .exp_sync = synchronize_rcu_tasks_rude, 857 .call = call_rcu_tasks_rude, 858 .cb_barrier = rcu_barrier_tasks_rude, 859 .gp_kthread_dbg = show_rcu_tasks_rude_gp_kthread, 860 .cbflood_max = 50000, 861 .fqs = NULL, 862 .stats = NULL, 863 .irq_capable = 1, 864 .name = "tasks-rude" 865 }; 866 867 #define TASKS_RUDE_OPS &tasks_rude_ops, 868 869 #else // #ifdef CONFIG_TASKS_RUDE_RCU 870 871 #define TASKS_RUDE_OPS 872 873 #endif // #else #ifdef CONFIG_TASKS_RUDE_RCU 874 875 876 #ifdef CONFIG_TASKS_TRACE_RCU 877 878 /* 879 * Definitions for tracing RCU-tasks torture testing. 880 */ 881 882 static int tasks_tracing_torture_read_lock(void) 883 { 884 rcu_read_lock_trace(); 885 return 0; 886 } 887 888 static void tasks_tracing_torture_read_unlock(int idx) 889 { 890 rcu_read_unlock_trace(); 891 } 892 893 static void rcu_tasks_tracing_torture_deferred_free(struct rcu_torture *p) 894 { 895 call_rcu_tasks_trace(&p->rtort_rcu, rcu_torture_cb); 896 } 897 898 static struct rcu_torture_ops tasks_tracing_ops = { 899 .ttype = RCU_TASKS_TRACING_FLAVOR, 900 .init = rcu_sync_torture_init, 901 .readlock = tasks_tracing_torture_read_lock, 902 .read_delay = srcu_read_delay, /* just reuse srcu's version. */ 903 .readunlock = tasks_tracing_torture_read_unlock, 904 .readlock_held = rcu_read_lock_trace_held, 905 .get_gp_seq = rcu_no_completed, 906 .deferred_free = rcu_tasks_tracing_torture_deferred_free, 907 .sync = synchronize_rcu_tasks_trace, 908 .exp_sync = synchronize_rcu_tasks_trace, 909 .call = call_rcu_tasks_trace, 910 .cb_barrier = rcu_barrier_tasks_trace, 911 .gp_kthread_dbg = show_rcu_tasks_trace_gp_kthread, 912 .cbflood_max = 50000, 913 .fqs = NULL, 914 .stats = NULL, 915 .irq_capable = 1, 916 .slow_gps = 1, 917 .name = "tasks-tracing" 918 }; 919 920 #define TASKS_TRACING_OPS &tasks_tracing_ops, 921 922 #else // #ifdef CONFIG_TASKS_TRACE_RCU 923 924 #define TASKS_TRACING_OPS 925 926 #endif // #else #ifdef CONFIG_TASKS_TRACE_RCU 927 928 929 static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old) 930 { 931 if (!cur_ops->gp_diff) 932 return new - old; 933 return cur_ops->gp_diff(new, old); 934 } 935 936 /* 937 * RCU torture priority-boost testing. Runs one real-time thread per 938 * CPU for moderate bursts, repeatedly starting grace periods and waiting 939 * for them to complete. If a given grace period takes too long, we assume 940 * that priority inversion has occurred. 941 */ 942 943 static int old_rt_runtime = -1; 944 945 static void rcu_torture_disable_rt_throttle(void) 946 { 947 /* 948 * Disable RT throttling so that rcutorture's boost threads don't get 949 * throttled. Only possible if rcutorture is built-in otherwise the 950 * user should manually do this by setting the sched_rt_period_us and 951 * sched_rt_runtime sysctls. 952 */ 953 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime != -1) 954 return; 955 956 old_rt_runtime = sysctl_sched_rt_runtime; 957 sysctl_sched_rt_runtime = -1; 958 } 959 960 static void rcu_torture_enable_rt_throttle(void) 961 { 962 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime == -1) 963 return; 964 965 sysctl_sched_rt_runtime = old_rt_runtime; 966 old_rt_runtime = -1; 967 } 968 969 static bool rcu_torture_boost_failed(unsigned long gp_state, unsigned long *start) 970 { 971 int cpu; 972 static int dbg_done; 973 unsigned long end = jiffies; 974 bool gp_done; 975 unsigned long j; 976 static unsigned long last_persist; 977 unsigned long lp; 978 unsigned long mininterval = test_boost_duration * HZ - HZ / 2; 979 980 if (end - *start > mininterval) { 981 // Recheck after checking time to avoid false positives. 982 smp_mb(); // Time check before grace-period check. 983 if (cur_ops->poll_gp_state(gp_state)) 984 return false; // passed, though perhaps just barely 985 if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, &cpu)) { 986 // At most one persisted message per boost test. 987 j = jiffies; 988 lp = READ_ONCE(last_persist); 989 if (time_after(j, lp + mininterval) && cmpxchg(&last_persist, lp, j) == lp) 990 pr_info("Boost inversion persisted: No QS from CPU %d\n", cpu); 991 return false; // passed on a technicality 992 } 993 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed"); 994 n_rcu_torture_boost_failure++; 995 if (!xchg(&dbg_done, 1) && cur_ops->gp_kthread_dbg) { 996 pr_info("Boost inversion thread ->rt_priority %u gp_state %lu jiffies %lu\n", 997 current->rt_priority, gp_state, end - *start); 998 cur_ops->gp_kthread_dbg(); 999 // Recheck after print to flag grace period ending during splat. 1000 gp_done = cur_ops->poll_gp_state(gp_state); 1001 pr_info("Boost inversion: GP %lu %s.\n", gp_state, 1002 gp_done ? "ended already" : "still pending"); 1003 1004 } 1005 1006 return true; // failed 1007 } else if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, NULL)) { 1008 *start = jiffies; 1009 } 1010 1011 return false; // passed 1012 } 1013 1014 static int rcu_torture_boost(void *arg) 1015 { 1016 unsigned long endtime; 1017 unsigned long gp_state; 1018 unsigned long gp_state_time; 1019 unsigned long oldstarttime; 1020 1021 VERBOSE_TOROUT_STRING("rcu_torture_boost started"); 1022 1023 /* Set real-time priority. */ 1024 sched_set_fifo_low(current); 1025 1026 /* Each pass through the following loop does one boost-test cycle. */ 1027 do { 1028 bool failed = false; // Test failed already in this test interval 1029 bool gp_initiated = false; 1030 1031 if (kthread_should_stop()) 1032 goto checkwait; 1033 1034 /* Wait for the next test interval. */ 1035 oldstarttime = READ_ONCE(boost_starttime); 1036 while (time_before(jiffies, oldstarttime)) { 1037 schedule_timeout_interruptible(oldstarttime - jiffies); 1038 if (stutter_wait("rcu_torture_boost")) 1039 sched_set_fifo_low(current); 1040 if (torture_must_stop()) 1041 goto checkwait; 1042 } 1043 1044 // Do one boost-test interval. 1045 endtime = oldstarttime + test_boost_duration * HZ; 1046 while (time_before(jiffies, endtime)) { 1047 // Has current GP gone too long? 1048 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state)) 1049 failed = rcu_torture_boost_failed(gp_state, &gp_state_time); 1050 // If we don't have a grace period in flight, start one. 1051 if (!gp_initiated || cur_ops->poll_gp_state(gp_state)) { 1052 gp_state = cur_ops->start_gp_poll(); 1053 gp_initiated = true; 1054 gp_state_time = jiffies; 1055 } 1056 if (stutter_wait("rcu_torture_boost")) { 1057 sched_set_fifo_low(current); 1058 // If the grace period already ended, 1059 // we don't know when that happened, so 1060 // start over. 1061 if (cur_ops->poll_gp_state(gp_state)) 1062 gp_initiated = false; 1063 } 1064 if (torture_must_stop()) 1065 goto checkwait; 1066 } 1067 1068 // In case the grace period extended beyond the end of the loop. 1069 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state)) 1070 rcu_torture_boost_failed(gp_state, &gp_state_time); 1071 1072 /* 1073 * Set the start time of the next test interval. 1074 * Yes, this is vulnerable to long delays, but such 1075 * delays simply cause a false negative for the next 1076 * interval. Besides, we are running at RT priority, 1077 * so delays should be relatively rare. 1078 */ 1079 while (oldstarttime == READ_ONCE(boost_starttime) && !kthread_should_stop()) { 1080 if (mutex_trylock(&boost_mutex)) { 1081 if (oldstarttime == boost_starttime) { 1082 WRITE_ONCE(boost_starttime, 1083 jiffies + test_boost_interval * HZ); 1084 n_rcu_torture_boosts++; 1085 } 1086 mutex_unlock(&boost_mutex); 1087 break; 1088 } 1089 schedule_timeout_uninterruptible(1); 1090 } 1091 1092 /* Go do the stutter. */ 1093 checkwait: if (stutter_wait("rcu_torture_boost")) 1094 sched_set_fifo_low(current); 1095 } while (!torture_must_stop()); 1096 1097 /* Clean up and exit. */ 1098 while (!kthread_should_stop()) { 1099 torture_shutdown_absorb("rcu_torture_boost"); 1100 schedule_timeout_uninterruptible(1); 1101 } 1102 torture_kthread_stopping("rcu_torture_boost"); 1103 return 0; 1104 } 1105 1106 /* 1107 * RCU torture force-quiescent-state kthread. Repeatedly induces 1108 * bursts of calls to force_quiescent_state(), increasing the probability 1109 * of occurrence of some important types of race conditions. 1110 */ 1111 static int 1112 rcu_torture_fqs(void *arg) 1113 { 1114 unsigned long fqs_resume_time; 1115 int fqs_burst_remaining; 1116 int oldnice = task_nice(current); 1117 1118 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started"); 1119 do { 1120 fqs_resume_time = jiffies + fqs_stutter * HZ; 1121 while (time_before(jiffies, fqs_resume_time) && 1122 !kthread_should_stop()) { 1123 schedule_timeout_interruptible(1); 1124 } 1125 fqs_burst_remaining = fqs_duration; 1126 while (fqs_burst_remaining > 0 && 1127 !kthread_should_stop()) { 1128 cur_ops->fqs(); 1129 udelay(fqs_holdoff); 1130 fqs_burst_remaining -= fqs_holdoff; 1131 } 1132 if (stutter_wait("rcu_torture_fqs")) 1133 sched_set_normal(current, oldnice); 1134 } while (!torture_must_stop()); 1135 torture_kthread_stopping("rcu_torture_fqs"); 1136 return 0; 1137 } 1138 1139 // Used by writers to randomly choose from the available grace-period 1140 // primitives. The only purpose of the initialization is to size the array. 1141 static int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC, RTWS_COND_GET, RTWS_POLL_GET, RTWS_SYNC }; 1142 static int nsynctypes; 1143 1144 /* 1145 * Determine which grace-period primitives are available. 1146 */ 1147 static void rcu_torture_write_types(void) 1148 { 1149 bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal; 1150 bool gp_poll1 = gp_poll, gp_sync1 = gp_sync; 1151 1152 /* Initialize synctype[] array. If none set, take default. */ 1153 if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_poll1 && !gp_sync1) 1154 gp_cond1 = gp_exp1 = gp_normal1 = gp_poll1 = gp_sync1 = true; 1155 if (gp_cond1 && cur_ops->get_gp_state && cur_ops->cond_sync) { 1156 synctype[nsynctypes++] = RTWS_COND_GET; 1157 pr_info("%s: Testing conditional GPs.\n", __func__); 1158 } else if (gp_cond && (!cur_ops->get_gp_state || !cur_ops->cond_sync)) { 1159 pr_alert("%s: gp_cond without primitives.\n", __func__); 1160 } 1161 if (gp_exp1 && cur_ops->exp_sync) { 1162 synctype[nsynctypes++] = RTWS_EXP_SYNC; 1163 pr_info("%s: Testing expedited GPs.\n", __func__); 1164 } else if (gp_exp && !cur_ops->exp_sync) { 1165 pr_alert("%s: gp_exp without primitives.\n", __func__); 1166 } 1167 if (gp_normal1 && cur_ops->deferred_free) { 1168 synctype[nsynctypes++] = RTWS_DEF_FREE; 1169 pr_info("%s: Testing asynchronous GPs.\n", __func__); 1170 } else if (gp_normal && !cur_ops->deferred_free) { 1171 pr_alert("%s: gp_normal without primitives.\n", __func__); 1172 } 1173 if (gp_poll1 && cur_ops->start_gp_poll && cur_ops->poll_gp_state) { 1174 synctype[nsynctypes++] = RTWS_POLL_GET; 1175 pr_info("%s: Testing polling GPs.\n", __func__); 1176 } else if (gp_poll && (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)) { 1177 pr_alert("%s: gp_poll without primitives.\n", __func__); 1178 } 1179 if (gp_sync1 && cur_ops->sync) { 1180 synctype[nsynctypes++] = RTWS_SYNC; 1181 pr_info("%s: Testing normal GPs.\n", __func__); 1182 } else if (gp_sync && !cur_ops->sync) { 1183 pr_alert("%s: gp_sync without primitives.\n", __func__); 1184 } 1185 } 1186 1187 /* 1188 * RCU torture writer kthread. Repeatedly substitutes a new structure 1189 * for that pointed to by rcu_torture_current, freeing the old structure 1190 * after a series of grace periods (the "pipeline"). 1191 */ 1192 static int 1193 rcu_torture_writer(void *arg) 1194 { 1195 bool boot_ended; 1196 bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal(); 1197 unsigned long cookie; 1198 int expediting = 0; 1199 unsigned long gp_snap; 1200 int i; 1201 int idx; 1202 int oldnice = task_nice(current); 1203 struct rcu_torture *rp; 1204 struct rcu_torture *old_rp; 1205 static DEFINE_TORTURE_RANDOM(rand); 1206 bool stutter_waited; 1207 1208 VERBOSE_TOROUT_STRING("rcu_torture_writer task started"); 1209 if (!can_expedite) 1210 pr_alert("%s" TORTURE_FLAG 1211 " GP expediting controlled from boot/sysfs for %s.\n", 1212 torture_type, cur_ops->name); 1213 if (WARN_ONCE(nsynctypes == 0, 1214 "%s: No update-side primitives.\n", __func__)) { 1215 /* 1216 * No updates primitives, so don't try updating. 1217 * The resulting test won't be testing much, hence the 1218 * above WARN_ONCE(). 1219 */ 1220 rcu_torture_writer_state = RTWS_STOPPING; 1221 torture_kthread_stopping("rcu_torture_writer"); 1222 return 0; 1223 } 1224 1225 do { 1226 rcu_torture_writer_state = RTWS_FIXED_DELAY; 1227 torture_hrtimeout_us(500, 1000, &rand); 1228 rp = rcu_torture_alloc(); 1229 if (rp == NULL) 1230 continue; 1231 rp->rtort_pipe_count = 0; 1232 rcu_torture_writer_state = RTWS_DELAY; 1233 udelay(torture_random(&rand) & 0x3ff); 1234 rcu_torture_writer_state = RTWS_REPLACE; 1235 old_rp = rcu_dereference_check(rcu_torture_current, 1236 current == writer_task); 1237 rp->rtort_mbtest = 1; 1238 rcu_assign_pointer(rcu_torture_current, rp); 1239 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */ 1240 if (old_rp) { 1241 i = old_rp->rtort_pipe_count; 1242 if (i > RCU_TORTURE_PIPE_LEN) 1243 i = RCU_TORTURE_PIPE_LEN; 1244 atomic_inc(&rcu_torture_wcount[i]); 1245 WRITE_ONCE(old_rp->rtort_pipe_count, 1246 old_rp->rtort_pipe_count + 1); 1247 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) { 1248 idx = cur_ops->readlock(); 1249 cookie = cur_ops->get_gp_state(); 1250 WARN_ONCE(rcu_torture_writer_state != RTWS_DEF_FREE && 1251 cur_ops->poll_gp_state(cookie), 1252 "%s: Cookie check 1 failed %s(%d) %lu->%lu\n", 1253 __func__, 1254 rcu_torture_writer_state_getname(), 1255 rcu_torture_writer_state, 1256 cookie, cur_ops->get_gp_state()); 1257 cur_ops->readunlock(idx); 1258 } 1259 switch (synctype[torture_random(&rand) % nsynctypes]) { 1260 case RTWS_DEF_FREE: 1261 rcu_torture_writer_state = RTWS_DEF_FREE; 1262 cur_ops->deferred_free(old_rp); 1263 break; 1264 case RTWS_EXP_SYNC: 1265 rcu_torture_writer_state = RTWS_EXP_SYNC; 1266 cur_ops->exp_sync(); 1267 rcu_torture_pipe_update(old_rp); 1268 break; 1269 case RTWS_COND_GET: 1270 rcu_torture_writer_state = RTWS_COND_GET; 1271 gp_snap = cur_ops->get_gp_state(); 1272 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); 1273 rcu_torture_writer_state = RTWS_COND_SYNC; 1274 cur_ops->cond_sync(gp_snap); 1275 rcu_torture_pipe_update(old_rp); 1276 break; 1277 case RTWS_POLL_GET: 1278 rcu_torture_writer_state = RTWS_POLL_GET; 1279 gp_snap = cur_ops->start_gp_poll(); 1280 rcu_torture_writer_state = RTWS_POLL_WAIT; 1281 while (!cur_ops->poll_gp_state(gp_snap)) 1282 torture_hrtimeout_jiffies(torture_random(&rand) % 16, 1283 &rand); 1284 rcu_torture_pipe_update(old_rp); 1285 break; 1286 case RTWS_SYNC: 1287 rcu_torture_writer_state = RTWS_SYNC; 1288 cur_ops->sync(); 1289 rcu_torture_pipe_update(old_rp); 1290 break; 1291 default: 1292 WARN_ON_ONCE(1); 1293 break; 1294 } 1295 } 1296 WRITE_ONCE(rcu_torture_current_version, 1297 rcu_torture_current_version + 1); 1298 /* Cycle through nesting levels of rcu_expedite_gp() calls. */ 1299 if (can_expedite && 1300 !(torture_random(&rand) & 0xff & (!!expediting - 1))) { 1301 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited()); 1302 if (expediting >= 0) 1303 rcu_expedite_gp(); 1304 else 1305 rcu_unexpedite_gp(); 1306 if (++expediting > 3) 1307 expediting = -expediting; 1308 } else if (!can_expedite) { /* Disabled during boot, recheck. */ 1309 can_expedite = !rcu_gp_is_expedited() && 1310 !rcu_gp_is_normal(); 1311 } 1312 rcu_torture_writer_state = RTWS_STUTTER; 1313 boot_ended = rcu_inkernel_boot_has_ended(); 1314 stutter_waited = stutter_wait("rcu_torture_writer"); 1315 if (stutter_waited && 1316 !atomic_read(&rcu_fwd_cb_nodelay) && 1317 !cur_ops->slow_gps && 1318 !torture_must_stop() && 1319 boot_ended) 1320 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) 1321 if (list_empty(&rcu_tortures[i].rtort_free) && 1322 rcu_access_pointer(rcu_torture_current) != 1323 &rcu_tortures[i]) { 1324 rcu_ftrace_dump(DUMP_ALL); 1325 WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count); 1326 } 1327 if (stutter_waited) 1328 sched_set_normal(current, oldnice); 1329 } while (!torture_must_stop()); 1330 rcu_torture_current = NULL; // Let stats task know that we are done. 1331 /* Reset expediting back to unexpedited. */ 1332 if (expediting > 0) 1333 expediting = -expediting; 1334 while (can_expedite && expediting++ < 0) 1335 rcu_unexpedite_gp(); 1336 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited()); 1337 if (!can_expedite) 1338 pr_alert("%s" TORTURE_FLAG 1339 " Dynamic grace-period expediting was disabled.\n", 1340 torture_type); 1341 rcu_torture_writer_state = RTWS_STOPPING; 1342 torture_kthread_stopping("rcu_torture_writer"); 1343 return 0; 1344 } 1345 1346 /* 1347 * RCU torture fake writer kthread. Repeatedly calls sync, with a random 1348 * delay between calls. 1349 */ 1350 static int 1351 rcu_torture_fakewriter(void *arg) 1352 { 1353 unsigned long gp_snap; 1354 DEFINE_TORTURE_RANDOM(rand); 1355 1356 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started"); 1357 set_user_nice(current, MAX_NICE); 1358 1359 if (WARN_ONCE(nsynctypes == 0, 1360 "%s: No update-side primitives.\n", __func__)) { 1361 /* 1362 * No updates primitives, so don't try updating. 1363 * The resulting test won't be testing much, hence the 1364 * above WARN_ONCE(). 1365 */ 1366 torture_kthread_stopping("rcu_torture_fakewriter"); 1367 return 0; 1368 } 1369 1370 do { 1371 torture_hrtimeout_jiffies(torture_random(&rand) % 10, &rand); 1372 if (cur_ops->cb_barrier != NULL && 1373 torture_random(&rand) % (nfakewriters * 8) == 0) { 1374 cur_ops->cb_barrier(); 1375 } else { 1376 switch (synctype[torture_random(&rand) % nsynctypes]) { 1377 case RTWS_DEF_FREE: 1378 break; 1379 case RTWS_EXP_SYNC: 1380 cur_ops->exp_sync(); 1381 break; 1382 case RTWS_COND_GET: 1383 gp_snap = cur_ops->get_gp_state(); 1384 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); 1385 cur_ops->cond_sync(gp_snap); 1386 break; 1387 case RTWS_POLL_GET: 1388 gp_snap = cur_ops->start_gp_poll(); 1389 while (!cur_ops->poll_gp_state(gp_snap)) { 1390 torture_hrtimeout_jiffies(torture_random(&rand) % 16, 1391 &rand); 1392 } 1393 break; 1394 case RTWS_SYNC: 1395 cur_ops->sync(); 1396 break; 1397 default: 1398 WARN_ON_ONCE(1); 1399 break; 1400 } 1401 } 1402 stutter_wait("rcu_torture_fakewriter"); 1403 } while (!torture_must_stop()); 1404 1405 torture_kthread_stopping("rcu_torture_fakewriter"); 1406 return 0; 1407 } 1408 1409 static void rcu_torture_timer_cb(struct rcu_head *rhp) 1410 { 1411 kfree(rhp); 1412 } 1413 1414 // Set up and carry out testing of RCU's global memory ordering 1415 static void rcu_torture_reader_do_mbchk(long myid, struct rcu_torture *rtp, 1416 struct torture_random_state *trsp) 1417 { 1418 unsigned long loops; 1419 int noc = torture_num_online_cpus(); 1420 int rdrchked; 1421 int rdrchker; 1422 struct rcu_torture_reader_check *rtrcp; // Me. 1423 struct rcu_torture_reader_check *rtrcp_assigner; // Assigned us to do checking. 1424 struct rcu_torture_reader_check *rtrcp_chked; // Reader being checked. 1425 struct rcu_torture_reader_check *rtrcp_chker; // Reader doing checking when not me. 1426 1427 if (myid < 0) 1428 return; // Don't try this from timer handlers. 1429 1430 // Increment my counter. 1431 rtrcp = &rcu_torture_reader_mbchk[myid]; 1432 WRITE_ONCE(rtrcp->rtc_myloops, rtrcp->rtc_myloops + 1); 1433 1434 // Attempt to assign someone else some checking work. 1435 rdrchked = torture_random(trsp) % nrealreaders; 1436 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked]; 1437 rdrchker = torture_random(trsp) % nrealreaders; 1438 rtrcp_chker = &rcu_torture_reader_mbchk[rdrchker]; 1439 if (rdrchked != myid && rdrchked != rdrchker && noc >= rdrchked && noc >= rdrchker && 1440 smp_load_acquire(&rtrcp->rtc_chkrdr) < 0 && // Pairs with smp_store_release below. 1441 !READ_ONCE(rtp->rtort_chkp) && 1442 !smp_load_acquire(&rtrcp_chker->rtc_assigner)) { // Pairs with smp_store_release below. 1443 rtrcp->rtc_chkloops = READ_ONCE(rtrcp_chked->rtc_myloops); 1444 WARN_ON_ONCE(rtrcp->rtc_chkrdr >= 0); 1445 rtrcp->rtc_chkrdr = rdrchked; 1446 WARN_ON_ONCE(rtrcp->rtc_ready); // This gets set after the grace period ends. 1447 if (cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, NULL, rtrcp) || 1448 cmpxchg_relaxed(&rtp->rtort_chkp, NULL, rtrcp)) 1449 (void)cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, rtrcp, NULL); // Back out. 1450 } 1451 1452 // If assigned some completed work, do it! 1453 rtrcp_assigner = READ_ONCE(rtrcp->rtc_assigner); 1454 if (!rtrcp_assigner || !smp_load_acquire(&rtrcp_assigner->rtc_ready)) 1455 return; // No work or work not yet ready. 1456 rdrchked = rtrcp_assigner->rtc_chkrdr; 1457 if (WARN_ON_ONCE(rdrchked < 0)) 1458 return; 1459 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked]; 1460 loops = READ_ONCE(rtrcp_chked->rtc_myloops); 1461 atomic_inc(&n_rcu_torture_mbchk_tries); 1462 if (ULONG_CMP_LT(loops, rtrcp_assigner->rtc_chkloops)) 1463 atomic_inc(&n_rcu_torture_mbchk_fail); 1464 rtrcp_assigner->rtc_chkloops = loops + ULONG_MAX / 2; 1465 rtrcp_assigner->rtc_ready = 0; 1466 smp_store_release(&rtrcp->rtc_assigner, NULL); // Someone else can assign us work. 1467 smp_store_release(&rtrcp_assigner->rtc_chkrdr, -1); // Assigner can again assign. 1468 } 1469 1470 /* 1471 * Do one extension of an RCU read-side critical section using the 1472 * current reader state in readstate (set to zero for initial entry 1473 * to extended critical section), set the new state as specified by 1474 * newstate (set to zero for final exit from extended critical section), 1475 * and random-number-generator state in trsp. If this is neither the 1476 * beginning or end of the critical section and if there was actually a 1477 * change, do a ->read_delay(). 1478 */ 1479 static void rcutorture_one_extend(int *readstate, int newstate, 1480 struct torture_random_state *trsp, 1481 struct rt_read_seg *rtrsp) 1482 { 1483 unsigned long flags; 1484 int idxnew1 = -1; 1485 int idxnew2 = -1; 1486 int idxold1 = *readstate; 1487 int idxold2 = idxold1; 1488 int statesnew = ~*readstate & newstate; 1489 int statesold = *readstate & ~newstate; 1490 1491 WARN_ON_ONCE(idxold2 < 0); 1492 WARN_ON_ONCE((idxold2 >> RCUTORTURE_RDR_SHIFT_2) > 1); 1493 rtrsp->rt_readstate = newstate; 1494 1495 /* First, put new protection in place to avoid critical-section gap. */ 1496 if (statesnew & RCUTORTURE_RDR_BH) 1497 local_bh_disable(); 1498 if (statesnew & RCUTORTURE_RDR_RBH) 1499 rcu_read_lock_bh(); 1500 if (statesnew & RCUTORTURE_RDR_IRQ) 1501 local_irq_disable(); 1502 if (statesnew & RCUTORTURE_RDR_PREEMPT) 1503 preempt_disable(); 1504 if (statesnew & RCUTORTURE_RDR_SCHED) 1505 rcu_read_lock_sched(); 1506 if (statesnew & RCUTORTURE_RDR_RCU_1) 1507 idxnew1 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_1; 1508 if (statesnew & RCUTORTURE_RDR_RCU_2) 1509 idxnew2 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_2; 1510 1511 /* 1512 * Next, remove old protection, in decreasing order of strength 1513 * to avoid unlock paths that aren't safe in the stronger 1514 * context. Namely: BH can not be enabled with disabled interrupts. 1515 * Additionally PREEMPT_RT requires that BH is enabled in preemptible 1516 * context. 1517 */ 1518 if (statesold & RCUTORTURE_RDR_IRQ) 1519 local_irq_enable(); 1520 if (statesold & RCUTORTURE_RDR_PREEMPT) 1521 preempt_enable(); 1522 if (statesold & RCUTORTURE_RDR_SCHED) 1523 rcu_read_unlock_sched(); 1524 if (statesold & RCUTORTURE_RDR_BH) 1525 local_bh_enable(); 1526 if (statesold & RCUTORTURE_RDR_RBH) 1527 rcu_read_unlock_bh(); 1528 if (statesold & RCUTORTURE_RDR_RCU_2) { 1529 cur_ops->readunlock((idxold2 >> RCUTORTURE_RDR_SHIFT_2) & 0x1); 1530 WARN_ON_ONCE(idxnew2 != -1); 1531 idxold2 = 0; 1532 } 1533 if (statesold & RCUTORTURE_RDR_RCU_1) { 1534 bool lockit; 1535 1536 lockit = !cur_ops->no_pi_lock && !statesnew && !(torture_random(trsp) & 0xffff); 1537 if (lockit) 1538 raw_spin_lock_irqsave(¤t->pi_lock, flags); 1539 cur_ops->readunlock((idxold1 >> RCUTORTURE_RDR_SHIFT_1) & 0x1); 1540 WARN_ON_ONCE(idxnew1 != -1); 1541 idxold1 = 0; 1542 if (lockit) 1543 raw_spin_unlock_irqrestore(¤t->pi_lock, flags); 1544 } 1545 1546 /* Delay if neither beginning nor end and there was a change. */ 1547 if ((statesnew || statesold) && *readstate && newstate) 1548 cur_ops->read_delay(trsp, rtrsp); 1549 1550 /* Update the reader state. */ 1551 if (idxnew1 == -1) 1552 idxnew1 = idxold1 & RCUTORTURE_RDR_MASK_1; 1553 WARN_ON_ONCE(idxnew1 < 0); 1554 if (WARN_ON_ONCE((idxnew1 >> RCUTORTURE_RDR_SHIFT_1) > 1)) 1555 pr_info("Unexpected idxnew1 value of %#x\n", idxnew1); 1556 if (idxnew2 == -1) 1557 idxnew2 = idxold2 & RCUTORTURE_RDR_MASK_2; 1558 WARN_ON_ONCE(idxnew2 < 0); 1559 WARN_ON_ONCE((idxnew2 >> RCUTORTURE_RDR_SHIFT_2) > 1); 1560 *readstate = idxnew1 | idxnew2 | newstate; 1561 WARN_ON_ONCE(*readstate < 0); 1562 if (WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT_2) > 1)) 1563 pr_info("Unexpected idxnew2 value of %#x\n", idxnew2); 1564 } 1565 1566 /* Return the biggest extendables mask given current RCU and boot parameters. */ 1567 static int rcutorture_extend_mask_max(void) 1568 { 1569 int mask; 1570 1571 WARN_ON_ONCE(extendables & ~RCUTORTURE_MAX_EXTEND); 1572 mask = extendables & RCUTORTURE_MAX_EXTEND & cur_ops->extendables; 1573 mask = mask | RCUTORTURE_RDR_RCU_1 | RCUTORTURE_RDR_RCU_2; 1574 return mask; 1575 } 1576 1577 /* Return a random protection state mask, but with at least one bit set. */ 1578 static int 1579 rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp) 1580 { 1581 int mask = rcutorture_extend_mask_max(); 1582 unsigned long randmask1 = torture_random(trsp) >> 8; 1583 unsigned long randmask2 = randmask1 >> 3; 1584 unsigned long preempts = RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED; 1585 unsigned long preempts_irq = preempts | RCUTORTURE_RDR_IRQ; 1586 unsigned long bhs = RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH; 1587 1588 WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT_1); 1589 /* Mostly only one bit (need preemption!), sometimes lots of bits. */ 1590 if (!(randmask1 & 0x7)) 1591 mask = mask & randmask2; 1592 else 1593 mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS)); 1594 1595 // Can't have nested RCU reader without outer RCU reader. 1596 if (!(mask & RCUTORTURE_RDR_RCU_1) && (mask & RCUTORTURE_RDR_RCU_2)) { 1597 if (oldmask & RCUTORTURE_RDR_RCU_1) 1598 mask &= ~RCUTORTURE_RDR_RCU_2; 1599 else 1600 mask |= RCUTORTURE_RDR_RCU_1; 1601 } 1602 1603 /* 1604 * Can't enable bh w/irq disabled. 1605 */ 1606 if (mask & RCUTORTURE_RDR_IRQ) 1607 mask |= oldmask & bhs; 1608 1609 /* 1610 * Ideally these sequences would be detected in debug builds 1611 * (regardless of RT), but until then don't stop testing 1612 * them on non-RT. 1613 */ 1614 if (IS_ENABLED(CONFIG_PREEMPT_RT)) { 1615 /* Can't modify BH in atomic context */ 1616 if (oldmask & preempts_irq) 1617 mask &= ~bhs; 1618 if ((oldmask | mask) & preempts_irq) 1619 mask |= oldmask & bhs; 1620 } 1621 1622 return mask ?: RCUTORTURE_RDR_RCU_1; 1623 } 1624 1625 /* 1626 * Do a randomly selected number of extensions of an existing RCU read-side 1627 * critical section. 1628 */ 1629 static struct rt_read_seg * 1630 rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp, 1631 struct rt_read_seg *rtrsp) 1632 { 1633 int i; 1634 int j; 1635 int mask = rcutorture_extend_mask_max(); 1636 1637 WARN_ON_ONCE(!*readstate); /* -Existing- RCU read-side critsect! */ 1638 if (!((mask - 1) & mask)) 1639 return rtrsp; /* Current RCU reader not extendable. */ 1640 /* Bias towards larger numbers of loops. */ 1641 i = (torture_random(trsp) >> 3); 1642 i = ((i | (i >> 3)) & RCUTORTURE_RDR_MAX_LOOPS) + 1; 1643 for (j = 0; j < i; j++) { 1644 mask = rcutorture_extend_mask(*readstate, trsp); 1645 rcutorture_one_extend(readstate, mask, trsp, &rtrsp[j]); 1646 } 1647 return &rtrsp[j]; 1648 } 1649 1650 /* 1651 * Do one read-side critical section, returning false if there was 1652 * no data to read. Can be invoked both from process context and 1653 * from a timer handler. 1654 */ 1655 static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid) 1656 { 1657 unsigned long cookie; 1658 int i; 1659 unsigned long started; 1660 unsigned long completed; 1661 int newstate; 1662 struct rcu_torture *p; 1663 int pipe_count; 1664 int readstate = 0; 1665 struct rt_read_seg rtseg[RCUTORTURE_RDR_MAX_SEGS] = { { 0 } }; 1666 struct rt_read_seg *rtrsp = &rtseg[0]; 1667 struct rt_read_seg *rtrsp1; 1668 unsigned long long ts; 1669 1670 WARN_ON_ONCE(!rcu_is_watching()); 1671 newstate = rcutorture_extend_mask(readstate, trsp); 1672 rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++); 1673 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) 1674 cookie = cur_ops->get_gp_state(); 1675 started = cur_ops->get_gp_seq(); 1676 ts = rcu_trace_clock_local(); 1677 p = rcu_dereference_check(rcu_torture_current, 1678 !cur_ops->readlock_held || cur_ops->readlock_held()); 1679 if (p == NULL) { 1680 /* Wait for rcu_torture_writer to get underway */ 1681 rcutorture_one_extend(&readstate, 0, trsp, rtrsp); 1682 return false; 1683 } 1684 if (p->rtort_mbtest == 0) 1685 atomic_inc(&n_rcu_torture_mberror); 1686 rcu_torture_reader_do_mbchk(myid, p, trsp); 1687 rtrsp = rcutorture_loop_extend(&readstate, trsp, rtrsp); 1688 preempt_disable(); 1689 pipe_count = READ_ONCE(p->rtort_pipe_count); 1690 if (pipe_count > RCU_TORTURE_PIPE_LEN) { 1691 /* Should not happen, but... */ 1692 pipe_count = RCU_TORTURE_PIPE_LEN; 1693 } 1694 completed = cur_ops->get_gp_seq(); 1695 if (pipe_count > 1) { 1696 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, 1697 ts, started, completed); 1698 rcu_ftrace_dump(DUMP_ALL); 1699 } 1700 __this_cpu_inc(rcu_torture_count[pipe_count]); 1701 completed = rcutorture_seq_diff(completed, started); 1702 if (completed > RCU_TORTURE_PIPE_LEN) { 1703 /* Should not happen, but... */ 1704 completed = RCU_TORTURE_PIPE_LEN; 1705 } 1706 __this_cpu_inc(rcu_torture_batch[completed]); 1707 preempt_enable(); 1708 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) 1709 WARN_ONCE(cur_ops->poll_gp_state(cookie), 1710 "%s: Cookie check 2 failed %s(%d) %lu->%lu\n", 1711 __func__, 1712 rcu_torture_writer_state_getname(), 1713 rcu_torture_writer_state, 1714 cookie, cur_ops->get_gp_state()); 1715 rcutorture_one_extend(&readstate, 0, trsp, rtrsp); 1716 WARN_ON_ONCE(readstate); 1717 // This next splat is expected behavior if leakpointer, especially 1718 // for CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels. 1719 WARN_ON_ONCE(leakpointer && READ_ONCE(p->rtort_pipe_count) > 1); 1720 1721 /* If error or close call, record the sequence of reader protections. */ 1722 if ((pipe_count > 1 || completed > 1) && !xchg(&err_segs_recorded, 1)) { 1723 i = 0; 1724 for (rtrsp1 = &rtseg[0]; rtrsp1 < rtrsp; rtrsp1++) 1725 err_segs[i++] = *rtrsp1; 1726 rt_read_nsegs = i; 1727 } 1728 1729 return true; 1730 } 1731 1732 static DEFINE_TORTURE_RANDOM_PERCPU(rcu_torture_timer_rand); 1733 1734 /* 1735 * RCU torture reader from timer handler. Dereferences rcu_torture_current, 1736 * incrementing the corresponding element of the pipeline array. The 1737 * counter in the element should never be greater than 1, otherwise, the 1738 * RCU implementation is broken. 1739 */ 1740 static void rcu_torture_timer(struct timer_list *unused) 1741 { 1742 atomic_long_inc(&n_rcu_torture_timers); 1743 (void)rcu_torture_one_read(this_cpu_ptr(&rcu_torture_timer_rand), -1); 1744 1745 /* Test call_rcu() invocation from interrupt handler. */ 1746 if (cur_ops->call) { 1747 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT); 1748 1749 if (rhp) 1750 cur_ops->call(rhp, rcu_torture_timer_cb); 1751 } 1752 } 1753 1754 /* 1755 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current, 1756 * incrementing the corresponding element of the pipeline array. The 1757 * counter in the element should never be greater than 1, otherwise, the 1758 * RCU implementation is broken. 1759 */ 1760 static int 1761 rcu_torture_reader(void *arg) 1762 { 1763 unsigned long lastsleep = jiffies; 1764 long myid = (long)arg; 1765 int mynumonline = myid; 1766 DEFINE_TORTURE_RANDOM(rand); 1767 struct timer_list t; 1768 1769 VERBOSE_TOROUT_STRING("rcu_torture_reader task started"); 1770 set_user_nice(current, MAX_NICE); 1771 if (irqreader && cur_ops->irq_capable) 1772 timer_setup_on_stack(&t, rcu_torture_timer, 0); 1773 tick_dep_set_task(current, TICK_DEP_BIT_RCU); 1774 do { 1775 if (irqreader && cur_ops->irq_capable) { 1776 if (!timer_pending(&t)) 1777 mod_timer(&t, jiffies + 1); 1778 } 1779 if (!rcu_torture_one_read(&rand, myid) && !torture_must_stop()) 1780 schedule_timeout_interruptible(HZ); 1781 if (time_after(jiffies, lastsleep) && !torture_must_stop()) { 1782 torture_hrtimeout_us(500, 1000, &rand); 1783 lastsleep = jiffies + 10; 1784 } 1785 while (torture_num_online_cpus() < mynumonline && !torture_must_stop()) 1786 schedule_timeout_interruptible(HZ / 5); 1787 stutter_wait("rcu_torture_reader"); 1788 } while (!torture_must_stop()); 1789 if (irqreader && cur_ops->irq_capable) { 1790 del_timer_sync(&t); 1791 destroy_timer_on_stack(&t); 1792 } 1793 tick_dep_clear_task(current, TICK_DEP_BIT_RCU); 1794 torture_kthread_stopping("rcu_torture_reader"); 1795 return 0; 1796 } 1797 1798 /* 1799 * Randomly Toggle CPUs' callback-offload state. This uses hrtimers to 1800 * increase race probabilities and fuzzes the interval between toggling. 1801 */ 1802 static int rcu_nocb_toggle(void *arg) 1803 { 1804 int cpu; 1805 int maxcpu = -1; 1806 int oldnice = task_nice(current); 1807 long r; 1808 DEFINE_TORTURE_RANDOM(rand); 1809 ktime_t toggle_delay; 1810 unsigned long toggle_fuzz; 1811 ktime_t toggle_interval = ms_to_ktime(nocbs_toggle); 1812 1813 VERBOSE_TOROUT_STRING("rcu_nocb_toggle task started"); 1814 while (!rcu_inkernel_boot_has_ended()) 1815 schedule_timeout_interruptible(HZ / 10); 1816 for_each_online_cpu(cpu) 1817 maxcpu = cpu; 1818 WARN_ON(maxcpu < 0); 1819 if (toggle_interval > ULONG_MAX) 1820 toggle_fuzz = ULONG_MAX >> 3; 1821 else 1822 toggle_fuzz = toggle_interval >> 3; 1823 if (toggle_fuzz <= 0) 1824 toggle_fuzz = NSEC_PER_USEC; 1825 do { 1826 r = torture_random(&rand); 1827 cpu = (r >> 4) % (maxcpu + 1); 1828 if (r & 0x1) { 1829 rcu_nocb_cpu_offload(cpu); 1830 atomic_long_inc(&n_nocb_offload); 1831 } else { 1832 rcu_nocb_cpu_deoffload(cpu); 1833 atomic_long_inc(&n_nocb_deoffload); 1834 } 1835 toggle_delay = torture_random(&rand) % toggle_fuzz + toggle_interval; 1836 set_current_state(TASK_INTERRUPTIBLE); 1837 schedule_hrtimeout(&toggle_delay, HRTIMER_MODE_REL); 1838 if (stutter_wait("rcu_nocb_toggle")) 1839 sched_set_normal(current, oldnice); 1840 } while (!torture_must_stop()); 1841 torture_kthread_stopping("rcu_nocb_toggle"); 1842 return 0; 1843 } 1844 1845 /* 1846 * Print torture statistics. Caller must ensure that there is only 1847 * one call to this function at a given time!!! This is normally 1848 * accomplished by relying on the module system to only have one copy 1849 * of the module loaded, and then by giving the rcu_torture_stats 1850 * kthread full control (or the init/cleanup functions when rcu_torture_stats 1851 * thread is not running). 1852 */ 1853 static void 1854 rcu_torture_stats_print(void) 1855 { 1856 int cpu; 1857 int i; 1858 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; 1859 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; 1860 struct rcu_torture *rtcp; 1861 static unsigned long rtcv_snap = ULONG_MAX; 1862 static bool splatted; 1863 struct task_struct *wtp; 1864 1865 for_each_possible_cpu(cpu) { 1866 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 1867 pipesummary[i] += READ_ONCE(per_cpu(rcu_torture_count, cpu)[i]); 1868 batchsummary[i] += READ_ONCE(per_cpu(rcu_torture_batch, cpu)[i]); 1869 } 1870 } 1871 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) { 1872 if (pipesummary[i] != 0) 1873 break; 1874 } 1875 1876 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1877 rtcp = rcu_access_pointer(rcu_torture_current); 1878 pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ", 1879 rtcp, 1880 rtcp && !rcu_stall_is_suppressed_at_boot() ? "ver" : "VER", 1881 rcu_torture_current_version, 1882 list_empty(&rcu_torture_freelist), 1883 atomic_read(&n_rcu_torture_alloc), 1884 atomic_read(&n_rcu_torture_alloc_fail), 1885 atomic_read(&n_rcu_torture_free)); 1886 pr_cont("rtmbe: %d rtmbkf: %d/%d rtbe: %ld rtbke: %ld rtbre: %ld ", 1887 atomic_read(&n_rcu_torture_mberror), 1888 atomic_read(&n_rcu_torture_mbchk_fail), atomic_read(&n_rcu_torture_mbchk_tries), 1889 n_rcu_torture_barrier_error, 1890 n_rcu_torture_boost_ktrerror, 1891 n_rcu_torture_boost_rterror); 1892 pr_cont("rtbf: %ld rtb: %ld nt: %ld ", 1893 n_rcu_torture_boost_failure, 1894 n_rcu_torture_boosts, 1895 atomic_long_read(&n_rcu_torture_timers)); 1896 torture_onoff_stats(); 1897 pr_cont("barrier: %ld/%ld:%ld ", 1898 data_race(n_barrier_successes), 1899 data_race(n_barrier_attempts), 1900 data_race(n_rcu_torture_barrier_error)); 1901 pr_cont("read-exits: %ld ", data_race(n_read_exits)); // Statistic. 1902 pr_cont("nocb-toggles: %ld:%ld\n", 1903 atomic_long_read(&n_nocb_offload), atomic_long_read(&n_nocb_deoffload)); 1904 1905 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1906 if (atomic_read(&n_rcu_torture_mberror) || 1907 atomic_read(&n_rcu_torture_mbchk_fail) || 1908 n_rcu_torture_barrier_error || n_rcu_torture_boost_ktrerror || 1909 n_rcu_torture_boost_rterror || n_rcu_torture_boost_failure || 1910 i > 1) { 1911 pr_cont("%s", "!!! "); 1912 atomic_inc(&n_rcu_torture_error); 1913 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mberror)); 1914 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mbchk_fail)); 1915 WARN_ON_ONCE(n_rcu_torture_barrier_error); // rcu_barrier() 1916 WARN_ON_ONCE(n_rcu_torture_boost_ktrerror); // no boost kthread 1917 WARN_ON_ONCE(n_rcu_torture_boost_rterror); // can't set RT prio 1918 WARN_ON_ONCE(n_rcu_torture_boost_failure); // boost failed (TIMER_SOFTIRQ RT prio?) 1919 WARN_ON_ONCE(i > 1); // Too-short grace period 1920 } 1921 pr_cont("Reader Pipe: "); 1922 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 1923 pr_cont(" %ld", pipesummary[i]); 1924 pr_cont("\n"); 1925 1926 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1927 pr_cont("Reader Batch: "); 1928 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 1929 pr_cont(" %ld", batchsummary[i]); 1930 pr_cont("\n"); 1931 1932 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1933 pr_cont("Free-Block Circulation: "); 1934 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 1935 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i])); 1936 } 1937 pr_cont("\n"); 1938 1939 if (cur_ops->stats) 1940 cur_ops->stats(); 1941 if (rtcv_snap == rcu_torture_current_version && 1942 rcu_access_pointer(rcu_torture_current) && 1943 !rcu_stall_is_suppressed()) { 1944 int __maybe_unused flags = 0; 1945 unsigned long __maybe_unused gp_seq = 0; 1946 1947 rcutorture_get_gp_data(cur_ops->ttype, 1948 &flags, &gp_seq); 1949 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, 1950 &flags, &gp_seq); 1951 wtp = READ_ONCE(writer_task); 1952 pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#x cpu %d\n", 1953 rcu_torture_writer_state_getname(), 1954 rcu_torture_writer_state, gp_seq, flags, 1955 wtp == NULL ? ~0U : wtp->__state, 1956 wtp == NULL ? -1 : (int)task_cpu(wtp)); 1957 if (!splatted && wtp) { 1958 sched_show_task(wtp); 1959 splatted = true; 1960 } 1961 if (cur_ops->gp_kthread_dbg) 1962 cur_ops->gp_kthread_dbg(); 1963 rcu_ftrace_dump(DUMP_ALL); 1964 } 1965 rtcv_snap = rcu_torture_current_version; 1966 } 1967 1968 /* 1969 * Periodically prints torture statistics, if periodic statistics printing 1970 * was specified via the stat_interval module parameter. 1971 */ 1972 static int 1973 rcu_torture_stats(void *arg) 1974 { 1975 VERBOSE_TOROUT_STRING("rcu_torture_stats task started"); 1976 do { 1977 schedule_timeout_interruptible(stat_interval * HZ); 1978 rcu_torture_stats_print(); 1979 torture_shutdown_absorb("rcu_torture_stats"); 1980 } while (!torture_must_stop()); 1981 torture_kthread_stopping("rcu_torture_stats"); 1982 return 0; 1983 } 1984 1985 /* Test mem_dump_obj() and friends. */ 1986 static void rcu_torture_mem_dump_obj(void) 1987 { 1988 struct rcu_head *rhp; 1989 struct kmem_cache *kcp; 1990 static int z; 1991 1992 kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL); 1993 rhp = kmem_cache_alloc(kcp, GFP_KERNEL); 1994 pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z); 1995 pr_alert("mem_dump_obj(ZERO_SIZE_PTR):"); 1996 mem_dump_obj(ZERO_SIZE_PTR); 1997 pr_alert("mem_dump_obj(NULL):"); 1998 mem_dump_obj(NULL); 1999 pr_alert("mem_dump_obj(%px):", &rhp); 2000 mem_dump_obj(&rhp); 2001 pr_alert("mem_dump_obj(%px):", rhp); 2002 mem_dump_obj(rhp); 2003 pr_alert("mem_dump_obj(%px):", &rhp->func); 2004 mem_dump_obj(&rhp->func); 2005 pr_alert("mem_dump_obj(%px):", &z); 2006 mem_dump_obj(&z); 2007 kmem_cache_free(kcp, rhp); 2008 kmem_cache_destroy(kcp); 2009 rhp = kmalloc(sizeof(*rhp), GFP_KERNEL); 2010 pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp); 2011 pr_alert("mem_dump_obj(kmalloc %px):", rhp); 2012 mem_dump_obj(rhp); 2013 pr_alert("mem_dump_obj(kmalloc %px):", &rhp->func); 2014 mem_dump_obj(&rhp->func); 2015 kfree(rhp); 2016 rhp = vmalloc(4096); 2017 pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp); 2018 pr_alert("mem_dump_obj(vmalloc %px):", rhp); 2019 mem_dump_obj(rhp); 2020 pr_alert("mem_dump_obj(vmalloc %px):", &rhp->func); 2021 mem_dump_obj(&rhp->func); 2022 vfree(rhp); 2023 } 2024 2025 static void 2026 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag) 2027 { 2028 pr_alert("%s" TORTURE_FLAG 2029 "--- %s: nreaders=%d nfakewriters=%d " 2030 "stat_interval=%d verbose=%d test_no_idle_hz=%d " 2031 "shuffle_interval=%d stutter=%d irqreader=%d " 2032 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d " 2033 "test_boost=%d/%d test_boost_interval=%d " 2034 "test_boost_duration=%d shutdown_secs=%d " 2035 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d " 2036 "stall_cpu_block=%d " 2037 "n_barrier_cbs=%d " 2038 "onoff_interval=%d onoff_holdoff=%d " 2039 "read_exit_delay=%d read_exit_burst=%d " 2040 "nocbs_nthreads=%d nocbs_toggle=%d\n", 2041 torture_type, tag, nrealreaders, nfakewriters, 2042 stat_interval, verbose, test_no_idle_hz, shuffle_interval, 2043 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter, 2044 test_boost, cur_ops->can_boost, 2045 test_boost_interval, test_boost_duration, shutdown_secs, 2046 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff, 2047 stall_cpu_block, 2048 n_barrier_cbs, 2049 onoff_interval, onoff_holdoff, 2050 read_exit_delay, read_exit_burst, 2051 nocbs_nthreads, nocbs_toggle); 2052 } 2053 2054 static int rcutorture_booster_cleanup(unsigned int cpu) 2055 { 2056 struct task_struct *t; 2057 2058 if (boost_tasks[cpu] == NULL) 2059 return 0; 2060 mutex_lock(&boost_mutex); 2061 t = boost_tasks[cpu]; 2062 boost_tasks[cpu] = NULL; 2063 rcu_torture_enable_rt_throttle(); 2064 mutex_unlock(&boost_mutex); 2065 2066 /* This must be outside of the mutex, otherwise deadlock! */ 2067 torture_stop_kthread(rcu_torture_boost, t); 2068 return 0; 2069 } 2070 2071 static int rcutorture_booster_init(unsigned int cpu) 2072 { 2073 int retval; 2074 2075 if (boost_tasks[cpu] != NULL) 2076 return 0; /* Already created, nothing more to do. */ 2077 2078 /* Don't allow time recalculation while creating a new task. */ 2079 mutex_lock(&boost_mutex); 2080 rcu_torture_disable_rt_throttle(); 2081 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task"); 2082 boost_tasks[cpu] = kthread_run_on_cpu(rcu_torture_boost, NULL, 2083 cpu, "rcu_torture_boost_%u"); 2084 if (IS_ERR(boost_tasks[cpu])) { 2085 retval = PTR_ERR(boost_tasks[cpu]); 2086 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed"); 2087 n_rcu_torture_boost_ktrerror++; 2088 boost_tasks[cpu] = NULL; 2089 mutex_unlock(&boost_mutex); 2090 return retval; 2091 } 2092 mutex_unlock(&boost_mutex); 2093 return 0; 2094 } 2095 2096 /* 2097 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then 2098 * induces a CPU stall for the time specified by stall_cpu. 2099 */ 2100 static int rcu_torture_stall(void *args) 2101 { 2102 int idx; 2103 unsigned long stop_at; 2104 2105 VERBOSE_TOROUT_STRING("rcu_torture_stall task started"); 2106 if (stall_cpu_holdoff > 0) { 2107 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff"); 2108 schedule_timeout_interruptible(stall_cpu_holdoff * HZ); 2109 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff"); 2110 } 2111 if (!kthread_should_stop() && stall_gp_kthread > 0) { 2112 VERBOSE_TOROUT_STRING("rcu_torture_stall begin GP stall"); 2113 rcu_gp_set_torture_wait(stall_gp_kthread * HZ); 2114 for (idx = 0; idx < stall_gp_kthread + 2; idx++) { 2115 if (kthread_should_stop()) 2116 break; 2117 schedule_timeout_uninterruptible(HZ); 2118 } 2119 } 2120 if (!kthread_should_stop() && stall_cpu > 0) { 2121 VERBOSE_TOROUT_STRING("rcu_torture_stall begin CPU stall"); 2122 stop_at = ktime_get_seconds() + stall_cpu; 2123 /* RCU CPU stall is expected behavior in following code. */ 2124 idx = cur_ops->readlock(); 2125 if (stall_cpu_irqsoff) 2126 local_irq_disable(); 2127 else if (!stall_cpu_block) 2128 preempt_disable(); 2129 pr_alert("%s start on CPU %d.\n", 2130 __func__, raw_smp_processor_id()); 2131 while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(), 2132 stop_at)) 2133 if (stall_cpu_block) { 2134 #ifdef CONFIG_PREEMPTION 2135 preempt_schedule(); 2136 #else 2137 schedule_timeout_uninterruptible(HZ); 2138 #endif 2139 } else if (stall_no_softlockup) { 2140 touch_softlockup_watchdog(); 2141 } 2142 if (stall_cpu_irqsoff) 2143 local_irq_enable(); 2144 else if (!stall_cpu_block) 2145 preempt_enable(); 2146 cur_ops->readunlock(idx); 2147 } 2148 pr_alert("%s end.\n", __func__); 2149 torture_shutdown_absorb("rcu_torture_stall"); 2150 while (!kthread_should_stop()) 2151 schedule_timeout_interruptible(10 * HZ); 2152 return 0; 2153 } 2154 2155 /* Spawn CPU-stall kthread, if stall_cpu specified. */ 2156 static int __init rcu_torture_stall_init(void) 2157 { 2158 if (stall_cpu <= 0 && stall_gp_kthread <= 0) 2159 return 0; 2160 return torture_create_kthread(rcu_torture_stall, NULL, stall_task); 2161 } 2162 2163 /* State structure for forward-progress self-propagating RCU callback. */ 2164 struct fwd_cb_state { 2165 struct rcu_head rh; 2166 int stop; 2167 }; 2168 2169 /* 2170 * Forward-progress self-propagating RCU callback function. Because 2171 * callbacks run from softirq, this function is an implicit RCU read-side 2172 * critical section. 2173 */ 2174 static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp) 2175 { 2176 struct fwd_cb_state *fcsp = container_of(rhp, struct fwd_cb_state, rh); 2177 2178 if (READ_ONCE(fcsp->stop)) { 2179 WRITE_ONCE(fcsp->stop, 2); 2180 return; 2181 } 2182 cur_ops->call(&fcsp->rh, rcu_torture_fwd_prog_cb); 2183 } 2184 2185 /* State for continuous-flood RCU callbacks. */ 2186 struct rcu_fwd_cb { 2187 struct rcu_head rh; 2188 struct rcu_fwd_cb *rfc_next; 2189 struct rcu_fwd *rfc_rfp; 2190 int rfc_gps; 2191 }; 2192 2193 #define MAX_FWD_CB_JIFFIES (8 * HZ) /* Maximum CB test duration. */ 2194 #define MIN_FWD_CB_LAUNDERS 3 /* This many CB invocations to count. */ 2195 #define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */ 2196 #define FWD_CBS_HIST_DIV 10 /* Histogram buckets/second. */ 2197 #define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV)) 2198 2199 struct rcu_launder_hist { 2200 long n_launders; 2201 unsigned long launder_gp_seq; 2202 }; 2203 2204 struct rcu_fwd { 2205 spinlock_t rcu_fwd_lock; 2206 struct rcu_fwd_cb *rcu_fwd_cb_head; 2207 struct rcu_fwd_cb **rcu_fwd_cb_tail; 2208 long n_launders_cb; 2209 unsigned long rcu_fwd_startat; 2210 struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST]; 2211 unsigned long rcu_launder_gp_seq_start; 2212 int rcu_fwd_id; 2213 }; 2214 2215 static DEFINE_MUTEX(rcu_fwd_mutex); 2216 static struct rcu_fwd *rcu_fwds; 2217 static unsigned long rcu_fwd_seq; 2218 static atomic_long_t rcu_fwd_max_cbs; 2219 static bool rcu_fwd_emergency_stop; 2220 2221 static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp) 2222 { 2223 unsigned long gps; 2224 unsigned long gps_old; 2225 int i; 2226 int j; 2227 2228 for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--) 2229 if (rfp->n_launders_hist[i].n_launders > 0) 2230 break; 2231 pr_alert("%s: Callback-invocation histogram %d (duration %lu jiffies):", 2232 __func__, rfp->rcu_fwd_id, jiffies - rfp->rcu_fwd_startat); 2233 gps_old = rfp->rcu_launder_gp_seq_start; 2234 for (j = 0; j <= i; j++) { 2235 gps = rfp->n_launders_hist[j].launder_gp_seq; 2236 pr_cont(" %ds/%d: %ld:%ld", 2237 j + 1, FWD_CBS_HIST_DIV, 2238 rfp->n_launders_hist[j].n_launders, 2239 rcutorture_seq_diff(gps, gps_old)); 2240 gps_old = gps; 2241 } 2242 pr_cont("\n"); 2243 } 2244 2245 /* Callback function for continuous-flood RCU callbacks. */ 2246 static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp) 2247 { 2248 unsigned long flags; 2249 int i; 2250 struct rcu_fwd_cb *rfcp = container_of(rhp, struct rcu_fwd_cb, rh); 2251 struct rcu_fwd_cb **rfcpp; 2252 struct rcu_fwd *rfp = rfcp->rfc_rfp; 2253 2254 rfcp->rfc_next = NULL; 2255 rfcp->rfc_gps++; 2256 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags); 2257 rfcpp = rfp->rcu_fwd_cb_tail; 2258 rfp->rcu_fwd_cb_tail = &rfcp->rfc_next; 2259 WRITE_ONCE(*rfcpp, rfcp); 2260 WRITE_ONCE(rfp->n_launders_cb, rfp->n_launders_cb + 1); 2261 i = ((jiffies - rfp->rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV)); 2262 if (i >= ARRAY_SIZE(rfp->n_launders_hist)) 2263 i = ARRAY_SIZE(rfp->n_launders_hist) - 1; 2264 rfp->n_launders_hist[i].n_launders++; 2265 rfp->n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq(); 2266 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 2267 } 2268 2269 // Give the scheduler a chance, even on nohz_full CPUs. 2270 static void rcu_torture_fwd_prog_cond_resched(unsigned long iter) 2271 { 2272 if (IS_ENABLED(CONFIG_PREEMPTION) && IS_ENABLED(CONFIG_NO_HZ_FULL)) { 2273 // Real call_rcu() floods hit userspace, so emulate that. 2274 if (need_resched() || (iter & 0xfff)) 2275 schedule(); 2276 return; 2277 } 2278 // No userspace emulation: CB invocation throttles call_rcu() 2279 cond_resched(); 2280 } 2281 2282 /* 2283 * Free all callbacks on the rcu_fwd_cb_head list, either because the 2284 * test is over or because we hit an OOM event. 2285 */ 2286 static unsigned long rcu_torture_fwd_prog_cbfree(struct rcu_fwd *rfp) 2287 { 2288 unsigned long flags; 2289 unsigned long freed = 0; 2290 struct rcu_fwd_cb *rfcp; 2291 2292 for (;;) { 2293 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags); 2294 rfcp = rfp->rcu_fwd_cb_head; 2295 if (!rfcp) { 2296 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 2297 break; 2298 } 2299 rfp->rcu_fwd_cb_head = rfcp->rfc_next; 2300 if (!rfp->rcu_fwd_cb_head) 2301 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head; 2302 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 2303 kfree(rfcp); 2304 freed++; 2305 rcu_torture_fwd_prog_cond_resched(freed); 2306 if (tick_nohz_full_enabled()) { 2307 local_irq_save(flags); 2308 rcu_momentary_dyntick_idle(); 2309 local_irq_restore(flags); 2310 } 2311 } 2312 return freed; 2313 } 2314 2315 /* Carry out need_resched()/cond_resched() forward-progress testing. */ 2316 static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp, 2317 int *tested, int *tested_tries) 2318 { 2319 unsigned long cver; 2320 unsigned long dur; 2321 struct fwd_cb_state fcs; 2322 unsigned long gps; 2323 int idx; 2324 int sd; 2325 int sd4; 2326 bool selfpropcb = false; 2327 unsigned long stopat; 2328 static DEFINE_TORTURE_RANDOM(trs); 2329 2330 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id); 2331 if (!cur_ops->sync) 2332 return; // Cannot do need_resched() forward progress testing without ->sync. 2333 if (cur_ops->call && cur_ops->cb_barrier) { 2334 init_rcu_head_on_stack(&fcs.rh); 2335 selfpropcb = true; 2336 } 2337 2338 /* Tight loop containing cond_resched(). */ 2339 atomic_inc(&rcu_fwd_cb_nodelay); 2340 cur_ops->sync(); /* Later readers see above write. */ 2341 if (selfpropcb) { 2342 WRITE_ONCE(fcs.stop, 0); 2343 cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb); 2344 } 2345 cver = READ_ONCE(rcu_torture_current_version); 2346 gps = cur_ops->get_gp_seq(); 2347 sd = cur_ops->stall_dur() + 1; 2348 sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div; 2349 dur = sd4 + torture_random(&trs) % (sd - sd4); 2350 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies); 2351 stopat = rfp->rcu_fwd_startat + dur; 2352 while (time_before(jiffies, stopat) && 2353 !shutdown_time_arrived() && 2354 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 2355 idx = cur_ops->readlock(); 2356 udelay(10); 2357 cur_ops->readunlock(idx); 2358 if (!fwd_progress_need_resched || need_resched()) 2359 cond_resched(); 2360 } 2361 (*tested_tries)++; 2362 if (!time_before(jiffies, stopat) && 2363 !shutdown_time_arrived() && 2364 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 2365 (*tested)++; 2366 cver = READ_ONCE(rcu_torture_current_version) - cver; 2367 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps); 2368 WARN_ON(!cver && gps < 2); 2369 pr_alert("%s: %d Duration %ld cver %ld gps %ld\n", __func__, 2370 rfp->rcu_fwd_id, dur, cver, gps); 2371 } 2372 if (selfpropcb) { 2373 WRITE_ONCE(fcs.stop, 1); 2374 cur_ops->sync(); /* Wait for running CB to complete. */ 2375 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id); 2376 cur_ops->cb_barrier(); /* Wait for queued callbacks. */ 2377 } 2378 2379 if (selfpropcb) { 2380 WARN_ON(READ_ONCE(fcs.stop) != 2); 2381 destroy_rcu_head_on_stack(&fcs.rh); 2382 } 2383 schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */ 2384 atomic_dec(&rcu_fwd_cb_nodelay); 2385 } 2386 2387 /* Carry out call_rcu() forward-progress testing. */ 2388 static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp) 2389 { 2390 unsigned long cver; 2391 unsigned long flags; 2392 unsigned long gps; 2393 int i; 2394 long n_launders; 2395 long n_launders_cb_snap; 2396 long n_launders_sa; 2397 long n_max_cbs; 2398 long n_max_gps; 2399 struct rcu_fwd_cb *rfcp; 2400 struct rcu_fwd_cb *rfcpn; 2401 unsigned long stopat; 2402 unsigned long stoppedat; 2403 2404 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id); 2405 if (READ_ONCE(rcu_fwd_emergency_stop)) 2406 return; /* Get out of the way quickly, no GP wait! */ 2407 if (!cur_ops->call) 2408 return; /* Can't do call_rcu() fwd prog without ->call. */ 2409 2410 /* Loop continuously posting RCU callbacks. */ 2411 atomic_inc(&rcu_fwd_cb_nodelay); 2412 cur_ops->sync(); /* Later readers see above write. */ 2413 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies); 2414 stopat = rfp->rcu_fwd_startat + MAX_FWD_CB_JIFFIES; 2415 n_launders = 0; 2416 rfp->n_launders_cb = 0; // Hoist initialization for multi-kthread 2417 n_launders_sa = 0; 2418 n_max_cbs = 0; 2419 n_max_gps = 0; 2420 for (i = 0; i < ARRAY_SIZE(rfp->n_launders_hist); i++) 2421 rfp->n_launders_hist[i].n_launders = 0; 2422 cver = READ_ONCE(rcu_torture_current_version); 2423 gps = cur_ops->get_gp_seq(); 2424 rfp->rcu_launder_gp_seq_start = gps; 2425 tick_dep_set_task(current, TICK_DEP_BIT_RCU); 2426 while (time_before(jiffies, stopat) && 2427 !shutdown_time_arrived() && 2428 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 2429 rfcp = READ_ONCE(rfp->rcu_fwd_cb_head); 2430 rfcpn = NULL; 2431 if (rfcp) 2432 rfcpn = READ_ONCE(rfcp->rfc_next); 2433 if (rfcpn) { 2434 if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS && 2435 ++n_max_gps >= MIN_FWD_CBS_LAUNDERED) 2436 break; 2437 rfp->rcu_fwd_cb_head = rfcpn; 2438 n_launders++; 2439 n_launders_sa++; 2440 } else if (!cur_ops->cbflood_max || cur_ops->cbflood_max > n_max_cbs) { 2441 rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL); 2442 if (WARN_ON_ONCE(!rfcp)) { 2443 schedule_timeout_interruptible(1); 2444 continue; 2445 } 2446 n_max_cbs++; 2447 n_launders_sa = 0; 2448 rfcp->rfc_gps = 0; 2449 rfcp->rfc_rfp = rfp; 2450 } else { 2451 rfcp = NULL; 2452 } 2453 if (rfcp) 2454 cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr); 2455 rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs); 2456 if (tick_nohz_full_enabled()) { 2457 local_irq_save(flags); 2458 rcu_momentary_dyntick_idle(); 2459 local_irq_restore(flags); 2460 } 2461 } 2462 stoppedat = jiffies; 2463 n_launders_cb_snap = READ_ONCE(rfp->n_launders_cb); 2464 cver = READ_ONCE(rcu_torture_current_version) - cver; 2465 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps); 2466 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id); 2467 cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */ 2468 (void)rcu_torture_fwd_prog_cbfree(rfp); 2469 2470 if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) && 2471 !shutdown_time_arrived()) { 2472 WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED); 2473 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", 2474 __func__, 2475 stoppedat - rfp->rcu_fwd_startat, jiffies - stoppedat, 2476 n_launders + n_max_cbs - n_launders_cb_snap, 2477 n_launders, n_launders_sa, 2478 n_max_gps, n_max_cbs, cver, gps); 2479 atomic_long_add(n_max_cbs, &rcu_fwd_max_cbs); 2480 mutex_lock(&rcu_fwd_mutex); // Serialize histograms. 2481 rcu_torture_fwd_cb_hist(rfp); 2482 mutex_unlock(&rcu_fwd_mutex); 2483 } 2484 schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */ 2485 tick_dep_clear_task(current, TICK_DEP_BIT_RCU); 2486 atomic_dec(&rcu_fwd_cb_nodelay); 2487 } 2488 2489 2490 /* 2491 * OOM notifier, but this only prints diagnostic information for the 2492 * current forward-progress test. 2493 */ 2494 static int rcutorture_oom_notify(struct notifier_block *self, 2495 unsigned long notused, void *nfreed) 2496 { 2497 int i; 2498 long ncbs; 2499 struct rcu_fwd *rfp; 2500 2501 mutex_lock(&rcu_fwd_mutex); 2502 rfp = rcu_fwds; 2503 if (!rfp) { 2504 mutex_unlock(&rcu_fwd_mutex); 2505 return NOTIFY_OK; 2506 } 2507 WARN(1, "%s invoked upon OOM during forward-progress testing.\n", 2508 __func__); 2509 for (i = 0; i < fwd_progress; i++) { 2510 rcu_torture_fwd_cb_hist(&rfp[i]); 2511 rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp[i].rcu_fwd_startat)) / 2); 2512 } 2513 WRITE_ONCE(rcu_fwd_emergency_stop, true); 2514 smp_mb(); /* Emergency stop before free and wait to avoid hangs. */ 2515 ncbs = 0; 2516 for (i = 0; i < fwd_progress; i++) 2517 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]); 2518 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs); 2519 rcu_barrier(); 2520 ncbs = 0; 2521 for (i = 0; i < fwd_progress; i++) 2522 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]); 2523 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs); 2524 rcu_barrier(); 2525 ncbs = 0; 2526 for (i = 0; i < fwd_progress; i++) 2527 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]); 2528 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs); 2529 smp_mb(); /* Frees before return to avoid redoing OOM. */ 2530 (*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */ 2531 pr_info("%s returning after OOM processing.\n", __func__); 2532 mutex_unlock(&rcu_fwd_mutex); 2533 return NOTIFY_OK; 2534 } 2535 2536 static struct notifier_block rcutorture_oom_nb = { 2537 .notifier_call = rcutorture_oom_notify 2538 }; 2539 2540 /* Carry out grace-period forward-progress testing. */ 2541 static int rcu_torture_fwd_prog(void *args) 2542 { 2543 bool firsttime = true; 2544 long max_cbs; 2545 int oldnice = task_nice(current); 2546 unsigned long oldseq = READ_ONCE(rcu_fwd_seq); 2547 struct rcu_fwd *rfp = args; 2548 int tested = 0; 2549 int tested_tries = 0; 2550 2551 VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started"); 2552 rcu_bind_current_to_nocb(); 2553 if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST)) 2554 set_user_nice(current, MAX_NICE); 2555 do { 2556 if (!rfp->rcu_fwd_id) { 2557 schedule_timeout_interruptible(fwd_progress_holdoff * HZ); 2558 WRITE_ONCE(rcu_fwd_emergency_stop, false); 2559 if (!firsttime) { 2560 max_cbs = atomic_long_xchg(&rcu_fwd_max_cbs, 0); 2561 pr_alert("%s n_max_cbs: %ld\n", __func__, max_cbs); 2562 } 2563 firsttime = false; 2564 WRITE_ONCE(rcu_fwd_seq, rcu_fwd_seq + 1); 2565 } else { 2566 while (READ_ONCE(rcu_fwd_seq) == oldseq && !torture_must_stop()) 2567 schedule_timeout_interruptible(1); 2568 oldseq = READ_ONCE(rcu_fwd_seq); 2569 } 2570 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id); 2571 if (rcu_inkernel_boot_has_ended() && torture_num_online_cpus() > rfp->rcu_fwd_id) 2572 rcu_torture_fwd_prog_cr(rfp); 2573 if ((cur_ops->stall_dur && cur_ops->stall_dur() > 0) && 2574 (!IS_ENABLED(CONFIG_TINY_RCU) || 2575 (rcu_inkernel_boot_has_ended() && 2576 torture_num_online_cpus() > rfp->rcu_fwd_id))) 2577 rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries); 2578 2579 /* Avoid slow periods, better to test when busy. */ 2580 if (stutter_wait("rcu_torture_fwd_prog")) 2581 sched_set_normal(current, oldnice); 2582 } while (!torture_must_stop()); 2583 /* Short runs might not contain a valid forward-progress attempt. */ 2584 if (!rfp->rcu_fwd_id) { 2585 WARN_ON(!tested && tested_tries >= 5); 2586 pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries); 2587 } 2588 torture_kthread_stopping("rcu_torture_fwd_prog"); 2589 return 0; 2590 } 2591 2592 /* If forward-progress checking is requested and feasible, spawn the thread. */ 2593 static int __init rcu_torture_fwd_prog_init(void) 2594 { 2595 int i; 2596 int ret = 0; 2597 struct rcu_fwd *rfp; 2598 2599 if (!fwd_progress) 2600 return 0; /* Not requested, so don't do it. */ 2601 if (fwd_progress >= nr_cpu_ids) { 2602 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Limiting fwd_progress to # CPUs.\n"); 2603 fwd_progress = nr_cpu_ids; 2604 } else if (fwd_progress < 0) { 2605 fwd_progress = nr_cpu_ids; 2606 } 2607 if ((!cur_ops->sync && !cur_ops->call) || 2608 (!cur_ops->cbflood_max && (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0)) || 2609 cur_ops == &rcu_busted_ops) { 2610 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test"); 2611 fwd_progress = 0; 2612 return 0; 2613 } 2614 if (stall_cpu > 0) { 2615 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing"); 2616 fwd_progress = 0; 2617 if (IS_MODULE(CONFIG_RCU_TORTURE_TEST)) 2618 return -EINVAL; /* In module, can fail back to user. */ 2619 WARN_ON(1); /* Make sure rcutorture notices conflict. */ 2620 return 0; 2621 } 2622 if (fwd_progress_holdoff <= 0) 2623 fwd_progress_holdoff = 1; 2624 if (fwd_progress_div <= 0) 2625 fwd_progress_div = 4; 2626 rfp = kcalloc(fwd_progress, sizeof(*rfp), GFP_KERNEL); 2627 fwd_prog_tasks = kcalloc(fwd_progress, sizeof(*fwd_prog_tasks), GFP_KERNEL); 2628 if (!rfp || !fwd_prog_tasks) { 2629 kfree(rfp); 2630 kfree(fwd_prog_tasks); 2631 fwd_prog_tasks = NULL; 2632 fwd_progress = 0; 2633 return -ENOMEM; 2634 } 2635 for (i = 0; i < fwd_progress; i++) { 2636 spin_lock_init(&rfp[i].rcu_fwd_lock); 2637 rfp[i].rcu_fwd_cb_tail = &rfp[i].rcu_fwd_cb_head; 2638 rfp[i].rcu_fwd_id = i; 2639 } 2640 mutex_lock(&rcu_fwd_mutex); 2641 rcu_fwds = rfp; 2642 mutex_unlock(&rcu_fwd_mutex); 2643 register_oom_notifier(&rcutorture_oom_nb); 2644 for (i = 0; i < fwd_progress; i++) { 2645 ret = torture_create_kthread(rcu_torture_fwd_prog, &rcu_fwds[i], fwd_prog_tasks[i]); 2646 if (ret) { 2647 fwd_progress = i; 2648 return ret; 2649 } 2650 } 2651 return 0; 2652 } 2653 2654 static void rcu_torture_fwd_prog_cleanup(void) 2655 { 2656 int i; 2657 struct rcu_fwd *rfp; 2658 2659 if (!rcu_fwds || !fwd_prog_tasks) 2660 return; 2661 for (i = 0; i < fwd_progress; i++) 2662 torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_tasks[i]); 2663 unregister_oom_notifier(&rcutorture_oom_nb); 2664 mutex_lock(&rcu_fwd_mutex); 2665 rfp = rcu_fwds; 2666 rcu_fwds = NULL; 2667 mutex_unlock(&rcu_fwd_mutex); 2668 kfree(rfp); 2669 kfree(fwd_prog_tasks); 2670 fwd_prog_tasks = NULL; 2671 } 2672 2673 /* Callback function for RCU barrier testing. */ 2674 static void rcu_torture_barrier_cbf(struct rcu_head *rcu) 2675 { 2676 atomic_inc(&barrier_cbs_invoked); 2677 } 2678 2679 /* IPI handler to get callback posted on desired CPU, if online. */ 2680 static void rcu_torture_barrier1cb(void *rcu_void) 2681 { 2682 struct rcu_head *rhp = rcu_void; 2683 2684 cur_ops->call(rhp, rcu_torture_barrier_cbf); 2685 } 2686 2687 /* kthread function to register callbacks used to test RCU barriers. */ 2688 static int rcu_torture_barrier_cbs(void *arg) 2689 { 2690 long myid = (long)arg; 2691 bool lastphase = false; 2692 bool newphase; 2693 struct rcu_head rcu; 2694 2695 init_rcu_head_on_stack(&rcu); 2696 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started"); 2697 set_user_nice(current, MAX_NICE); 2698 do { 2699 wait_event(barrier_cbs_wq[myid], 2700 (newphase = 2701 smp_load_acquire(&barrier_phase)) != lastphase || 2702 torture_must_stop()); 2703 lastphase = newphase; 2704 if (torture_must_stop()) 2705 break; 2706 /* 2707 * The above smp_load_acquire() ensures barrier_phase load 2708 * is ordered before the following ->call(). 2709 */ 2710 if (smp_call_function_single(myid, rcu_torture_barrier1cb, 2711 &rcu, 1)) { 2712 // IPI failed, so use direct call from current CPU. 2713 cur_ops->call(&rcu, rcu_torture_barrier_cbf); 2714 } 2715 if (atomic_dec_and_test(&barrier_cbs_count)) 2716 wake_up(&barrier_wq); 2717 } while (!torture_must_stop()); 2718 if (cur_ops->cb_barrier != NULL) 2719 cur_ops->cb_barrier(); 2720 destroy_rcu_head_on_stack(&rcu); 2721 torture_kthread_stopping("rcu_torture_barrier_cbs"); 2722 return 0; 2723 } 2724 2725 /* kthread function to drive and coordinate RCU barrier testing. */ 2726 static int rcu_torture_barrier(void *arg) 2727 { 2728 int i; 2729 2730 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting"); 2731 do { 2732 atomic_set(&barrier_cbs_invoked, 0); 2733 atomic_set(&barrier_cbs_count, n_barrier_cbs); 2734 /* Ensure barrier_phase ordered after prior assignments. */ 2735 smp_store_release(&barrier_phase, !barrier_phase); 2736 for (i = 0; i < n_barrier_cbs; i++) 2737 wake_up(&barrier_cbs_wq[i]); 2738 wait_event(barrier_wq, 2739 atomic_read(&barrier_cbs_count) == 0 || 2740 torture_must_stop()); 2741 if (torture_must_stop()) 2742 break; 2743 n_barrier_attempts++; 2744 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */ 2745 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) { 2746 n_rcu_torture_barrier_error++; 2747 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n", 2748 atomic_read(&barrier_cbs_invoked), 2749 n_barrier_cbs); 2750 WARN_ON(1); 2751 // Wait manually for the remaining callbacks 2752 i = 0; 2753 do { 2754 if (WARN_ON(i++ > HZ)) 2755 i = INT_MIN; 2756 schedule_timeout_interruptible(1); 2757 cur_ops->cb_barrier(); 2758 } while (atomic_read(&barrier_cbs_invoked) != 2759 n_barrier_cbs && 2760 !torture_must_stop()); 2761 smp_mb(); // Can't trust ordering if broken. 2762 if (!torture_must_stop()) 2763 pr_err("Recovered: barrier_cbs_invoked = %d\n", 2764 atomic_read(&barrier_cbs_invoked)); 2765 } else { 2766 n_barrier_successes++; 2767 } 2768 schedule_timeout_interruptible(HZ / 10); 2769 } while (!torture_must_stop()); 2770 torture_kthread_stopping("rcu_torture_barrier"); 2771 return 0; 2772 } 2773 2774 /* Initialize RCU barrier testing. */ 2775 static int rcu_torture_barrier_init(void) 2776 { 2777 int i; 2778 int ret; 2779 2780 if (n_barrier_cbs <= 0) 2781 return 0; 2782 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) { 2783 pr_alert("%s" TORTURE_FLAG 2784 " Call or barrier ops missing for %s,\n", 2785 torture_type, cur_ops->name); 2786 pr_alert("%s" TORTURE_FLAG 2787 " RCU barrier testing omitted from run.\n", 2788 torture_type); 2789 return 0; 2790 } 2791 atomic_set(&barrier_cbs_count, 0); 2792 atomic_set(&barrier_cbs_invoked, 0); 2793 barrier_cbs_tasks = 2794 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]), 2795 GFP_KERNEL); 2796 barrier_cbs_wq = 2797 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL); 2798 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq) 2799 return -ENOMEM; 2800 for (i = 0; i < n_barrier_cbs; i++) { 2801 init_waitqueue_head(&barrier_cbs_wq[i]); 2802 ret = torture_create_kthread(rcu_torture_barrier_cbs, 2803 (void *)(long)i, 2804 barrier_cbs_tasks[i]); 2805 if (ret) 2806 return ret; 2807 } 2808 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task); 2809 } 2810 2811 /* Clean up after RCU barrier testing. */ 2812 static void rcu_torture_barrier_cleanup(void) 2813 { 2814 int i; 2815 2816 torture_stop_kthread(rcu_torture_barrier, barrier_task); 2817 if (barrier_cbs_tasks != NULL) { 2818 for (i = 0; i < n_barrier_cbs; i++) 2819 torture_stop_kthread(rcu_torture_barrier_cbs, 2820 barrier_cbs_tasks[i]); 2821 kfree(barrier_cbs_tasks); 2822 barrier_cbs_tasks = NULL; 2823 } 2824 if (barrier_cbs_wq != NULL) { 2825 kfree(barrier_cbs_wq); 2826 barrier_cbs_wq = NULL; 2827 } 2828 } 2829 2830 static bool rcu_torture_can_boost(void) 2831 { 2832 static int boost_warn_once; 2833 int prio; 2834 2835 if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2) 2836 return false; 2837 if (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state) 2838 return false; 2839 2840 prio = rcu_get_gp_kthreads_prio(); 2841 if (!prio) 2842 return false; 2843 2844 if (prio < 2) { 2845 if (boost_warn_once == 1) 2846 return false; 2847 2848 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); 2849 boost_warn_once = 1; 2850 return false; 2851 } 2852 2853 return true; 2854 } 2855 2856 static bool read_exit_child_stop; 2857 static bool read_exit_child_stopped; 2858 static wait_queue_head_t read_exit_wq; 2859 2860 // Child kthread which just does an rcutorture reader and exits. 2861 static int rcu_torture_read_exit_child(void *trsp_in) 2862 { 2863 struct torture_random_state *trsp = trsp_in; 2864 2865 set_user_nice(current, MAX_NICE); 2866 // Minimize time between reading and exiting. 2867 while (!kthread_should_stop()) 2868 schedule_timeout_uninterruptible(1); 2869 (void)rcu_torture_one_read(trsp, -1); 2870 return 0; 2871 } 2872 2873 // Parent kthread which creates and destroys read-exit child kthreads. 2874 static int rcu_torture_read_exit(void *unused) 2875 { 2876 int count = 0; 2877 bool errexit = false; 2878 int i; 2879 struct task_struct *tsp; 2880 DEFINE_TORTURE_RANDOM(trs); 2881 2882 // Allocate and initialize. 2883 set_user_nice(current, MAX_NICE); 2884 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of test"); 2885 2886 // Each pass through this loop does one read-exit episode. 2887 do { 2888 if (++count > read_exit_burst) { 2889 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: End of episode"); 2890 rcu_barrier(); // Wait for task_struct free, avoid OOM. 2891 for (i = 0; i < read_exit_delay; i++) { 2892 schedule_timeout_uninterruptible(HZ); 2893 if (READ_ONCE(read_exit_child_stop)) 2894 break; 2895 } 2896 if (!READ_ONCE(read_exit_child_stop)) 2897 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of episode"); 2898 count = 0; 2899 } 2900 if (READ_ONCE(read_exit_child_stop)) 2901 break; 2902 // Spawn child. 2903 tsp = kthread_run(rcu_torture_read_exit_child, 2904 &trs, "%s", 2905 "rcu_torture_read_exit_child"); 2906 if (IS_ERR(tsp)) { 2907 TOROUT_ERRSTRING("out of memory"); 2908 errexit = true; 2909 tsp = NULL; 2910 break; 2911 } 2912 cond_resched(); 2913 kthread_stop(tsp); 2914 n_read_exits ++; 2915 stutter_wait("rcu_torture_read_exit"); 2916 } while (!errexit && !READ_ONCE(read_exit_child_stop)); 2917 2918 // Clean up and exit. 2919 smp_store_release(&read_exit_child_stopped, true); // After reaping. 2920 smp_mb(); // Store before wakeup. 2921 wake_up(&read_exit_wq); 2922 while (!torture_must_stop()) 2923 schedule_timeout_uninterruptible(1); 2924 torture_kthread_stopping("rcu_torture_read_exit"); 2925 return 0; 2926 } 2927 2928 static int rcu_torture_read_exit_init(void) 2929 { 2930 if (read_exit_burst <= 0) 2931 return 0; 2932 init_waitqueue_head(&read_exit_wq); 2933 read_exit_child_stop = false; 2934 read_exit_child_stopped = false; 2935 return torture_create_kthread(rcu_torture_read_exit, NULL, 2936 read_exit_task); 2937 } 2938 2939 static void rcu_torture_read_exit_cleanup(void) 2940 { 2941 if (!read_exit_task) 2942 return; 2943 WRITE_ONCE(read_exit_child_stop, true); 2944 smp_mb(); // Above write before wait. 2945 wait_event(read_exit_wq, smp_load_acquire(&read_exit_child_stopped)); 2946 torture_stop_kthread(rcutorture_read_exit, read_exit_task); 2947 } 2948 2949 static enum cpuhp_state rcutor_hp; 2950 2951 static void 2952 rcu_torture_cleanup(void) 2953 { 2954 int firsttime; 2955 int flags = 0; 2956 unsigned long gp_seq = 0; 2957 int i; 2958 2959 if (torture_cleanup_begin()) { 2960 if (cur_ops->cb_barrier != NULL) { 2961 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier); 2962 cur_ops->cb_barrier(); 2963 } 2964 rcu_gp_slow_unregister(NULL); 2965 return; 2966 } 2967 if (!cur_ops) { 2968 torture_cleanup_end(); 2969 rcu_gp_slow_unregister(NULL); 2970 return; 2971 } 2972 2973 if (cur_ops->gp_kthread_dbg) 2974 cur_ops->gp_kthread_dbg(); 2975 rcu_torture_read_exit_cleanup(); 2976 rcu_torture_barrier_cleanup(); 2977 rcu_torture_fwd_prog_cleanup(); 2978 torture_stop_kthread(rcu_torture_stall, stall_task); 2979 torture_stop_kthread(rcu_torture_writer, writer_task); 2980 2981 if (nocb_tasks) { 2982 for (i = 0; i < nrealnocbers; i++) 2983 torture_stop_kthread(rcu_nocb_toggle, nocb_tasks[i]); 2984 kfree(nocb_tasks); 2985 nocb_tasks = NULL; 2986 } 2987 2988 if (reader_tasks) { 2989 for (i = 0; i < nrealreaders; i++) 2990 torture_stop_kthread(rcu_torture_reader, 2991 reader_tasks[i]); 2992 kfree(reader_tasks); 2993 reader_tasks = NULL; 2994 } 2995 kfree(rcu_torture_reader_mbchk); 2996 rcu_torture_reader_mbchk = NULL; 2997 2998 if (fakewriter_tasks) { 2999 for (i = 0; i < nfakewriters; i++) 3000 torture_stop_kthread(rcu_torture_fakewriter, 3001 fakewriter_tasks[i]); 3002 kfree(fakewriter_tasks); 3003 fakewriter_tasks = NULL; 3004 } 3005 3006 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq); 3007 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq); 3008 pr_alert("%s: End-test grace-period state: g%ld f%#x total-gps=%ld\n", 3009 cur_ops->name, (long)gp_seq, flags, 3010 rcutorture_seq_diff(gp_seq, start_gp_seq)); 3011 torture_stop_kthread(rcu_torture_stats, stats_task); 3012 torture_stop_kthread(rcu_torture_fqs, fqs_task); 3013 if (rcu_torture_can_boost() && rcutor_hp >= 0) 3014 cpuhp_remove_state(rcutor_hp); 3015 3016 /* 3017 * Wait for all RCU callbacks to fire, then do torture-type-specific 3018 * cleanup operations. 3019 */ 3020 if (cur_ops->cb_barrier != NULL) { 3021 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier); 3022 cur_ops->cb_barrier(); 3023 } 3024 if (cur_ops->cleanup != NULL) 3025 cur_ops->cleanup(); 3026 3027 rcu_torture_mem_dump_obj(); 3028 3029 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */ 3030 3031 if (err_segs_recorded) { 3032 pr_alert("Failure/close-call rcutorture reader segments:\n"); 3033 if (rt_read_nsegs == 0) 3034 pr_alert("\t: No segments recorded!!!\n"); 3035 firsttime = 1; 3036 for (i = 0; i < rt_read_nsegs; i++) { 3037 pr_alert("\t%d: %#x ", i, err_segs[i].rt_readstate); 3038 if (err_segs[i].rt_delay_jiffies != 0) { 3039 pr_cont("%s%ldjiffies", firsttime ? "" : "+", 3040 err_segs[i].rt_delay_jiffies); 3041 firsttime = 0; 3042 } 3043 if (err_segs[i].rt_delay_ms != 0) { 3044 pr_cont("%s%ldms", firsttime ? "" : "+", 3045 err_segs[i].rt_delay_ms); 3046 firsttime = 0; 3047 } 3048 if (err_segs[i].rt_delay_us != 0) { 3049 pr_cont("%s%ldus", firsttime ? "" : "+", 3050 err_segs[i].rt_delay_us); 3051 firsttime = 0; 3052 } 3053 pr_cont("%s\n", 3054 err_segs[i].rt_preempted ? "preempted" : ""); 3055 3056 } 3057 } 3058 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error) 3059 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE"); 3060 else if (torture_onoff_failures()) 3061 rcu_torture_print_module_parms(cur_ops, 3062 "End of test: RCU_HOTPLUG"); 3063 else 3064 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS"); 3065 torture_cleanup_end(); 3066 rcu_gp_slow_unregister(&rcu_fwd_cb_nodelay); 3067 } 3068 3069 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD 3070 static void rcu_torture_leak_cb(struct rcu_head *rhp) 3071 { 3072 } 3073 3074 static void rcu_torture_err_cb(struct rcu_head *rhp) 3075 { 3076 /* 3077 * This -might- happen due to race conditions, but is unlikely. 3078 * The scenario that leads to this happening is that the 3079 * first of the pair of duplicate callbacks is queued, 3080 * someone else starts a grace period that includes that 3081 * callback, then the second of the pair must wait for the 3082 * next grace period. Unlikely, but can happen. If it 3083 * does happen, the debug-objects subsystem won't have splatted. 3084 */ 3085 pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME); 3086 } 3087 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 3088 3089 /* 3090 * Verify that double-free causes debug-objects to complain, but only 3091 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test 3092 * cannot be carried out. 3093 */ 3094 static void rcu_test_debug_objects(void) 3095 { 3096 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD 3097 struct rcu_head rh1; 3098 struct rcu_head rh2; 3099 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_KERNEL); 3100 3101 init_rcu_head_on_stack(&rh1); 3102 init_rcu_head_on_stack(&rh2); 3103 pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME); 3104 3105 /* Try to queue the rh2 pair of callbacks for the same grace period. */ 3106 preempt_disable(); /* Prevent preemption from interrupting test. */ 3107 rcu_read_lock(); /* Make it impossible to finish a grace period. */ 3108 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */ 3109 local_irq_disable(); /* Make it harder to start a new grace period. */ 3110 call_rcu(&rh2, rcu_torture_leak_cb); 3111 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */ 3112 if (rhp) { 3113 call_rcu(rhp, rcu_torture_leak_cb); 3114 call_rcu(rhp, rcu_torture_err_cb); /* Another duplicate callback. */ 3115 } 3116 local_irq_enable(); 3117 rcu_read_unlock(); 3118 preempt_enable(); 3119 3120 /* Wait for them all to get done so we can safely return. */ 3121 rcu_barrier(); 3122 pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME); 3123 destroy_rcu_head_on_stack(&rh1); 3124 destroy_rcu_head_on_stack(&rh2); 3125 #else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 3126 pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME); 3127 #endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 3128 } 3129 3130 static void rcutorture_sync(void) 3131 { 3132 static unsigned long n; 3133 3134 if (cur_ops->sync && !(++n & 0xfff)) 3135 cur_ops->sync(); 3136 } 3137 3138 static int __init 3139 rcu_torture_init(void) 3140 { 3141 long i; 3142 int cpu; 3143 int firsterr = 0; 3144 int flags = 0; 3145 unsigned long gp_seq = 0; 3146 static struct rcu_torture_ops *torture_ops[] = { 3147 &rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops, &busted_srcud_ops, 3148 TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS 3149 &trivial_ops, 3150 }; 3151 3152 if (!torture_init_begin(torture_type, verbose)) 3153 return -EBUSY; 3154 3155 /* Process args and tell the world that the torturer is on the job. */ 3156 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) { 3157 cur_ops = torture_ops[i]; 3158 if (strcmp(torture_type, cur_ops->name) == 0) 3159 break; 3160 } 3161 if (i == ARRAY_SIZE(torture_ops)) { 3162 pr_alert("rcu-torture: invalid torture type: \"%s\"\n", 3163 torture_type); 3164 pr_alert("rcu-torture types:"); 3165 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) 3166 pr_cont(" %s", torture_ops[i]->name); 3167 pr_cont("\n"); 3168 firsterr = -EINVAL; 3169 cur_ops = NULL; 3170 goto unwind; 3171 } 3172 if (cur_ops->fqs == NULL && fqs_duration != 0) { 3173 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n"); 3174 fqs_duration = 0; 3175 } 3176 if (cur_ops->init) 3177 cur_ops->init(); 3178 3179 if (nreaders >= 0) { 3180 nrealreaders = nreaders; 3181 } else { 3182 nrealreaders = num_online_cpus() - 2 - nreaders; 3183 if (nrealreaders <= 0) 3184 nrealreaders = 1; 3185 } 3186 rcu_torture_print_module_parms(cur_ops, "Start of test"); 3187 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq); 3188 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq); 3189 start_gp_seq = gp_seq; 3190 pr_alert("%s: Start-test grace-period state: g%ld f%#x\n", 3191 cur_ops->name, (long)gp_seq, flags); 3192 3193 /* Set up the freelist. */ 3194 3195 INIT_LIST_HEAD(&rcu_torture_freelist); 3196 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) { 3197 rcu_tortures[i].rtort_mbtest = 0; 3198 list_add_tail(&rcu_tortures[i].rtort_free, 3199 &rcu_torture_freelist); 3200 } 3201 3202 /* Initialize the statistics so that each run gets its own numbers. */ 3203 3204 rcu_torture_current = NULL; 3205 rcu_torture_current_version = 0; 3206 atomic_set(&n_rcu_torture_alloc, 0); 3207 atomic_set(&n_rcu_torture_alloc_fail, 0); 3208 atomic_set(&n_rcu_torture_free, 0); 3209 atomic_set(&n_rcu_torture_mberror, 0); 3210 atomic_set(&n_rcu_torture_mbchk_fail, 0); 3211 atomic_set(&n_rcu_torture_mbchk_tries, 0); 3212 atomic_set(&n_rcu_torture_error, 0); 3213 n_rcu_torture_barrier_error = 0; 3214 n_rcu_torture_boost_ktrerror = 0; 3215 n_rcu_torture_boost_rterror = 0; 3216 n_rcu_torture_boost_failure = 0; 3217 n_rcu_torture_boosts = 0; 3218 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 3219 atomic_set(&rcu_torture_wcount[i], 0); 3220 for_each_possible_cpu(cpu) { 3221 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 3222 per_cpu(rcu_torture_count, cpu)[i] = 0; 3223 per_cpu(rcu_torture_batch, cpu)[i] = 0; 3224 } 3225 } 3226 err_segs_recorded = 0; 3227 rt_read_nsegs = 0; 3228 3229 /* Start up the kthreads. */ 3230 3231 rcu_torture_write_types(); 3232 firsterr = torture_create_kthread(rcu_torture_writer, NULL, 3233 writer_task); 3234 if (torture_init_error(firsterr)) 3235 goto unwind; 3236 if (nfakewriters > 0) { 3237 fakewriter_tasks = kcalloc(nfakewriters, 3238 sizeof(fakewriter_tasks[0]), 3239 GFP_KERNEL); 3240 if (fakewriter_tasks == NULL) { 3241 TOROUT_ERRSTRING("out of memory"); 3242 firsterr = -ENOMEM; 3243 goto unwind; 3244 } 3245 } 3246 for (i = 0; i < nfakewriters; i++) { 3247 firsterr = torture_create_kthread(rcu_torture_fakewriter, 3248 NULL, fakewriter_tasks[i]); 3249 if (torture_init_error(firsterr)) 3250 goto unwind; 3251 } 3252 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]), 3253 GFP_KERNEL); 3254 rcu_torture_reader_mbchk = kcalloc(nrealreaders, sizeof(*rcu_torture_reader_mbchk), 3255 GFP_KERNEL); 3256 if (!reader_tasks || !rcu_torture_reader_mbchk) { 3257 TOROUT_ERRSTRING("out of memory"); 3258 firsterr = -ENOMEM; 3259 goto unwind; 3260 } 3261 for (i = 0; i < nrealreaders; i++) { 3262 rcu_torture_reader_mbchk[i].rtc_chkrdr = -1; 3263 firsterr = torture_create_kthread(rcu_torture_reader, (void *)i, 3264 reader_tasks[i]); 3265 if (torture_init_error(firsterr)) 3266 goto unwind; 3267 } 3268 nrealnocbers = nocbs_nthreads; 3269 if (WARN_ON(nrealnocbers < 0)) 3270 nrealnocbers = 1; 3271 if (WARN_ON(nocbs_toggle < 0)) 3272 nocbs_toggle = HZ; 3273 if (nrealnocbers > 0) { 3274 nocb_tasks = kcalloc(nrealnocbers, sizeof(nocb_tasks[0]), GFP_KERNEL); 3275 if (nocb_tasks == NULL) { 3276 TOROUT_ERRSTRING("out of memory"); 3277 firsterr = -ENOMEM; 3278 goto unwind; 3279 } 3280 } else { 3281 nocb_tasks = NULL; 3282 } 3283 for (i = 0; i < nrealnocbers; i++) { 3284 firsterr = torture_create_kthread(rcu_nocb_toggle, NULL, nocb_tasks[i]); 3285 if (torture_init_error(firsterr)) 3286 goto unwind; 3287 } 3288 if (stat_interval > 0) { 3289 firsterr = torture_create_kthread(rcu_torture_stats, NULL, 3290 stats_task); 3291 if (torture_init_error(firsterr)) 3292 goto unwind; 3293 } 3294 if (test_no_idle_hz && shuffle_interval > 0) { 3295 firsterr = torture_shuffle_init(shuffle_interval * HZ); 3296 if (torture_init_error(firsterr)) 3297 goto unwind; 3298 } 3299 if (stutter < 0) 3300 stutter = 0; 3301 if (stutter) { 3302 int t; 3303 3304 t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ; 3305 firsterr = torture_stutter_init(stutter * HZ, t); 3306 if (torture_init_error(firsterr)) 3307 goto unwind; 3308 } 3309 if (fqs_duration < 0) 3310 fqs_duration = 0; 3311 if (fqs_duration) { 3312 /* Create the fqs thread */ 3313 firsterr = torture_create_kthread(rcu_torture_fqs, NULL, 3314 fqs_task); 3315 if (torture_init_error(firsterr)) 3316 goto unwind; 3317 } 3318 if (test_boost_interval < 1) 3319 test_boost_interval = 1; 3320 if (test_boost_duration < 2) 3321 test_boost_duration = 2; 3322 if (rcu_torture_can_boost()) { 3323 3324 boost_starttime = jiffies + test_boost_interval * HZ; 3325 3326 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE", 3327 rcutorture_booster_init, 3328 rcutorture_booster_cleanup); 3329 rcutor_hp = firsterr; 3330 if (torture_init_error(firsterr)) 3331 goto unwind; 3332 3333 // Testing RCU priority boosting requires rcutorture do 3334 // some serious abuse. Counter this by running ksoftirqd 3335 // at higher priority. 3336 if (IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)) { 3337 for_each_online_cpu(cpu) { 3338 struct sched_param sp; 3339 struct task_struct *t; 3340 3341 t = per_cpu(ksoftirqd, cpu); 3342 WARN_ON_ONCE(!t); 3343 sp.sched_priority = 2; 3344 sched_setscheduler_nocheck(t, SCHED_FIFO, &sp); 3345 } 3346 } 3347 } 3348 shutdown_jiffies = jiffies + shutdown_secs * HZ; 3349 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup); 3350 if (torture_init_error(firsterr)) 3351 goto unwind; 3352 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval, 3353 rcutorture_sync); 3354 if (torture_init_error(firsterr)) 3355 goto unwind; 3356 firsterr = rcu_torture_stall_init(); 3357 if (torture_init_error(firsterr)) 3358 goto unwind; 3359 firsterr = rcu_torture_fwd_prog_init(); 3360 if (torture_init_error(firsterr)) 3361 goto unwind; 3362 firsterr = rcu_torture_barrier_init(); 3363 if (torture_init_error(firsterr)) 3364 goto unwind; 3365 firsterr = rcu_torture_read_exit_init(); 3366 if (torture_init_error(firsterr)) 3367 goto unwind; 3368 if (object_debug) 3369 rcu_test_debug_objects(); 3370 torture_init_end(); 3371 rcu_gp_slow_register(&rcu_fwd_cb_nodelay); 3372 return 0; 3373 3374 unwind: 3375 torture_init_end(); 3376 rcu_torture_cleanup(); 3377 if (shutdown_secs) { 3378 WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST)); 3379 kernel_power_off(); 3380 } 3381 return firsterr; 3382 } 3383 3384 module_init(rcu_torture_init); 3385 module_exit(rcu_torture_cleanup); 3386