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