1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Read-Copy Update module-based torture test facility 4 * 5 * Copyright (C) IBM Corporation, 2005, 2006 6 * 7 * Authors: Paul E. McKenney <paulmck@linux.ibm.com> 8 * Josh Triplett <josh@joshtriplett.org> 9 * 10 * See also: Documentation/RCU/torture.rst 11 */ 12 13 #define pr_fmt(fmt) fmt 14 15 #include <linux/types.h> 16 #include <linux/kernel.h> 17 #include <linux/init.h> 18 #include <linux/module.h> 19 #include <linux/kthread.h> 20 #include <linux/err.h> 21 #include <linux/spinlock.h> 22 #include <linux/smp.h> 23 #include <linux/rcupdate_wait.h> 24 #include <linux/interrupt.h> 25 #include <linux/sched/signal.h> 26 #include <uapi/linux/sched/types.h> 27 #include <linux/atomic.h> 28 #include <linux/bitops.h> 29 #include <linux/completion.h> 30 #include <linux/moduleparam.h> 31 #include <linux/percpu.h> 32 #include <linux/notifier.h> 33 #include <linux/reboot.h> 34 #include <linux/freezer.h> 35 #include <linux/cpu.h> 36 #include <linux/delay.h> 37 #include <linux/stat.h> 38 #include <linux/srcu.h> 39 #include <linux/slab.h> 40 #include <linux/trace_clock.h> 41 #include <asm/byteorder.h> 42 #include <linux/torture.h> 43 #include <linux/vmalloc.h> 44 #include <linux/sched/debug.h> 45 #include <linux/sched/sysctl.h> 46 #include <linux/oom.h> 47 #include <linux/tick.h> 48 #include <linux/rcupdate_trace.h> 49 #include <linux/nmi.h> 50 51 #include "rcu.h" 52 53 MODULE_LICENSE("GPL"); 54 MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com> and Josh Triplett <josh@joshtriplett.org>"); 55 56 /* Bits for ->extendables field, extendables param, and related definitions. */ 57 #define RCUTORTURE_RDR_SHIFT_1 8 /* Put SRCU index in upper bits. */ 58 #define RCUTORTURE_RDR_MASK_1 (1 << RCUTORTURE_RDR_SHIFT_1) 59 #define RCUTORTURE_RDR_SHIFT_2 9 /* Put SRCU index in upper bits. */ 60 #define RCUTORTURE_RDR_MASK_2 (1 << RCUTORTURE_RDR_SHIFT_2) 61 #define RCUTORTURE_RDR_BH 0x01 /* Extend readers by disabling bh. */ 62 #define RCUTORTURE_RDR_IRQ 0x02 /* ... disabling interrupts. */ 63 #define RCUTORTURE_RDR_PREEMPT 0x04 /* ... disabling preemption. */ 64 #define RCUTORTURE_RDR_RBH 0x08 /* ... rcu_read_lock_bh(). */ 65 #define RCUTORTURE_RDR_SCHED 0x10 /* ... rcu_read_lock_sched(). */ 66 #define RCUTORTURE_RDR_RCU_1 0x20 /* ... entering another RCU reader. */ 67 #define RCUTORTURE_RDR_RCU_2 0x40 /* ... entering another RCU reader. */ 68 #define RCUTORTURE_RDR_NBITS 7 /* Number of bits defined above. */ 69 #define RCUTORTURE_MAX_EXTEND \ 70 (RCUTORTURE_RDR_BH | RCUTORTURE_RDR_IRQ | RCUTORTURE_RDR_PREEMPT | \ 71 RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED) 72 #define RCUTORTURE_RDR_MAX_LOOPS 0x7 /* Maximum reader extensions. */ 73 /* Must be power of two minus one. */ 74 #define RCUTORTURE_RDR_MAX_SEGS (RCUTORTURE_RDR_MAX_LOOPS + 3) 75 76 torture_param(int, extendables, RCUTORTURE_MAX_EXTEND, 77 "Extend readers by disabling bh (1), irqs (2), or preempt (4)"); 78 torture_param(int, fqs_duration, 0, 79 "Duration of fqs bursts (us), 0 to disable"); 80 torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)"); 81 torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)"); 82 torture_param(int, fwd_progress, 1, "Test grace-period forward progress"); 83 torture_param(int, fwd_progress_div, 4, "Fraction of CPU stall to wait"); 84 torture_param(int, fwd_progress_holdoff, 60, 85 "Time between forward-progress tests (s)"); 86 torture_param(bool, fwd_progress_need_resched, 1, 87 "Hide cond_resched() behind need_resched()"); 88 torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives"); 89 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives"); 90 torture_param(bool, gp_normal, false, 91 "Use normal (non-expedited) GP wait primitives"); 92 torture_param(bool, gp_poll, false, "Use polling GP wait primitives"); 93 torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives"); 94 torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers"); 95 torture_param(int, leakpointer, 0, "Leak pointer dereferences from readers"); 96 torture_param(int, n_barrier_cbs, 0, 97 "# of callbacks/kthreads for barrier testing"); 98 torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads"); 99 torture_param(int, nreaders, -1, "Number of RCU reader threads"); 100 torture_param(int, object_debug, 0, 101 "Enable debug-object double call_rcu() testing"); 102 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)"); 103 torture_param(int, onoff_interval, 0, 104 "Time between CPU hotplugs (jiffies), 0=disable"); 105 torture_param(int, nocbs_nthreads, 0, "Number of NOCB toggle threads, 0 to disable"); 106 torture_param(int, nocbs_toggle, 1000, "Time between toggling nocb state (ms)"); 107 torture_param(int, read_exit_delay, 13, 108 "Delay between read-then-exit episodes (s)"); 109 torture_param(int, read_exit_burst, 16, 110 "# of read-then-exit bursts per episode, zero to disable"); 111 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles"); 112 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable."); 113 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable."); 114 torture_param(int, stall_cpu_holdoff, 10, 115 "Time to wait before starting stall (s)."); 116 torture_param(bool, stall_no_softlockup, false, 117 "Avoid softlockup warning during cpu stall."); 118 torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling."); 119 torture_param(int, stall_cpu_block, 0, "Sleep while stalling."); 120 torture_param(int, stall_gp_kthread, 0, 121 "Grace-period kthread stall duration (s)."); 122 torture_param(int, stat_interval, 60, 123 "Number of seconds between stats printk()s"); 124 torture_param(int, stutter, 5, "Number of seconds to run/halt test"); 125 torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes."); 126 torture_param(int, test_boost_duration, 4, 127 "Duration of each boost test, seconds."); 128 torture_param(int, test_boost_interval, 7, 129 "Interval between boost tests, seconds."); 130 torture_param(bool, test_no_idle_hz, true, 131 "Test support for tickless idle CPUs"); 132 torture_param(int, verbose, 1, 133 "Enable verbose debugging printk()s"); 134 135 static char *torture_type = "rcu"; 136 module_param(torture_type, charp, 0444); 137 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, srcu, ...)"); 138 139 static int nrealnocbers; 140 static int nrealreaders; 141 static struct task_struct *writer_task; 142 static struct task_struct **fakewriter_tasks; 143 static struct task_struct **reader_tasks; 144 static struct task_struct **nocb_tasks; 145 static struct task_struct *stats_task; 146 static struct task_struct *fqs_task; 147 static struct task_struct *boost_tasks[NR_CPUS]; 148 static struct task_struct *stall_task; 149 static struct task_struct **fwd_prog_tasks; 150 static struct task_struct **barrier_cbs_tasks; 151 static struct task_struct *barrier_task; 152 static struct task_struct *read_exit_task; 153 154 #define RCU_TORTURE_PIPE_LEN 10 155 156 // Mailbox-like structure to check RCU global memory ordering. 157 struct rcu_torture_reader_check { 158 unsigned long rtc_myloops; 159 int rtc_chkrdr; 160 unsigned long rtc_chkloops; 161 int rtc_ready; 162 struct rcu_torture_reader_check *rtc_assigner; 163 } ____cacheline_internodealigned_in_smp; 164 165 // Update-side data structure used to check RCU readers. 166 struct rcu_torture { 167 struct rcu_head rtort_rcu; 168 int rtort_pipe_count; 169 struct list_head rtort_free; 170 int rtort_mbtest; 171 struct rcu_torture_reader_check *rtort_chkp; 172 }; 173 174 static LIST_HEAD(rcu_torture_freelist); 175 static struct rcu_torture __rcu *rcu_torture_current; 176 static unsigned long rcu_torture_current_version; 177 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN]; 178 static DEFINE_SPINLOCK(rcu_torture_lock); 179 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count); 180 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch); 181 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1]; 182 static struct rcu_torture_reader_check *rcu_torture_reader_mbchk; 183 static atomic_t n_rcu_torture_alloc; 184 static atomic_t n_rcu_torture_alloc_fail; 185 static atomic_t n_rcu_torture_free; 186 static atomic_t n_rcu_torture_mberror; 187 static atomic_t n_rcu_torture_mbchk_fail; 188 static atomic_t n_rcu_torture_mbchk_tries; 189 static atomic_t n_rcu_torture_error; 190 static long n_rcu_torture_barrier_error; 191 static long n_rcu_torture_boost_ktrerror; 192 static long n_rcu_torture_boost_rterror; 193 static long n_rcu_torture_boost_failure; 194 static long n_rcu_torture_boosts; 195 static atomic_long_t n_rcu_torture_timers; 196 static long n_barrier_attempts; 197 static long n_barrier_successes; /* did rcu_barrier test succeed? */ 198 static unsigned long n_read_exits; 199 static struct list_head rcu_torture_removed; 200 static unsigned long shutdown_jiffies; 201 static unsigned long start_gp_seq; 202 static atomic_long_t n_nocb_offload; 203 static atomic_long_t n_nocb_deoffload; 204 205 static int rcu_torture_writer_state; 206 #define RTWS_FIXED_DELAY 0 207 #define RTWS_DELAY 1 208 #define RTWS_REPLACE 2 209 #define RTWS_DEF_FREE 3 210 #define RTWS_EXP_SYNC 4 211 #define RTWS_COND_GET 5 212 #define RTWS_COND_SYNC 6 213 #define RTWS_POLL_GET 7 214 #define RTWS_POLL_WAIT 8 215 #define RTWS_SYNC 9 216 #define RTWS_STUTTER 10 217 #define RTWS_STOPPING 11 218 static const char * const rcu_torture_writer_state_names[] = { 219 "RTWS_FIXED_DELAY", 220 "RTWS_DELAY", 221 "RTWS_REPLACE", 222 "RTWS_DEF_FREE", 223 "RTWS_EXP_SYNC", 224 "RTWS_COND_GET", 225 "RTWS_COND_SYNC", 226 "RTWS_POLL_GET", 227 "RTWS_POLL_WAIT", 228 "RTWS_SYNC", 229 "RTWS_STUTTER", 230 "RTWS_STOPPING", 231 }; 232 233 /* Record reader segment types and duration for first failing read. */ 234 struct rt_read_seg { 235 int rt_readstate; 236 unsigned long rt_delay_jiffies; 237 unsigned long rt_delay_ms; 238 unsigned long rt_delay_us; 239 bool rt_preempted; 240 }; 241 static int err_segs_recorded; 242 static struct rt_read_seg err_segs[RCUTORTURE_RDR_MAX_SEGS]; 243 static int rt_read_nsegs; 244 245 static const char *rcu_torture_writer_state_getname(void) 246 { 247 unsigned int i = READ_ONCE(rcu_torture_writer_state); 248 249 if (i >= ARRAY_SIZE(rcu_torture_writer_state_names)) 250 return "???"; 251 return rcu_torture_writer_state_names[i]; 252 } 253 254 #ifdef CONFIG_RCU_TRACE 255 static u64 notrace rcu_trace_clock_local(void) 256 { 257 u64 ts = trace_clock_local(); 258 259 (void)do_div(ts, NSEC_PER_USEC); 260 return ts; 261 } 262 #else /* #ifdef CONFIG_RCU_TRACE */ 263 static u64 notrace rcu_trace_clock_local(void) 264 { 265 return 0ULL; 266 } 267 #endif /* #else #ifdef CONFIG_RCU_TRACE */ 268 269 /* 270 * Stop aggressive CPU-hog tests a bit before the end of the test in order 271 * to avoid interfering with test shutdown. 272 */ 273 static bool shutdown_time_arrived(void) 274 { 275 return shutdown_secs && time_after(jiffies, shutdown_jiffies - 30 * HZ); 276 } 277 278 static unsigned long boost_starttime; /* jiffies of next boost test start. */ 279 static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */ 280 /* and boost task create/destroy. */ 281 static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */ 282 static bool barrier_phase; /* Test phase. */ 283 static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */ 284 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */ 285 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq); 286 287 static atomic_t rcu_fwd_cb_nodelay; /* Short rcu_torture_delay() delays. */ 288 289 /* 290 * Allocate an element from the rcu_tortures pool. 291 */ 292 static struct rcu_torture * 293 rcu_torture_alloc(void) 294 { 295 struct list_head *p; 296 297 spin_lock_bh(&rcu_torture_lock); 298 if (list_empty(&rcu_torture_freelist)) { 299 atomic_inc(&n_rcu_torture_alloc_fail); 300 spin_unlock_bh(&rcu_torture_lock); 301 return NULL; 302 } 303 atomic_inc(&n_rcu_torture_alloc); 304 p = rcu_torture_freelist.next; 305 list_del_init(p); 306 spin_unlock_bh(&rcu_torture_lock); 307 return container_of(p, struct rcu_torture, rtort_free); 308 } 309 310 /* 311 * Free an element to the rcu_tortures pool. 312 */ 313 static void 314 rcu_torture_free(struct rcu_torture *p) 315 { 316 atomic_inc(&n_rcu_torture_free); 317 spin_lock_bh(&rcu_torture_lock); 318 list_add_tail(&p->rtort_free, &rcu_torture_freelist); 319 spin_unlock_bh(&rcu_torture_lock); 320 } 321 322 /* 323 * Operations vector for selecting different types of tests. 324 */ 325 326 struct rcu_torture_ops { 327 int ttype; 328 void (*init)(void); 329 void (*cleanup)(void); 330 int (*readlock)(void); 331 void (*read_delay)(struct torture_random_state *rrsp, 332 struct rt_read_seg *rtrsp); 333 void (*readunlock)(int idx); 334 int (*readlock_held)(void); 335 unsigned long (*get_gp_seq)(void); 336 unsigned long (*gp_diff)(unsigned long new, unsigned long old); 337 void (*deferred_free)(struct rcu_torture *p); 338 void (*sync)(void); 339 void (*exp_sync)(void); 340 unsigned long (*get_gp_state)(void); 341 unsigned long (*start_gp_poll)(void); 342 bool (*poll_gp_state)(unsigned long oldstate); 343 void (*cond_sync)(unsigned long oldstate); 344 call_rcu_func_t call; 345 void (*cb_barrier)(void); 346 void (*fqs)(void); 347 void (*stats)(void); 348 void (*gp_kthread_dbg)(void); 349 bool (*check_boost_failed)(unsigned long gp_state, int *cpup); 350 int (*stall_dur)(void); 351 long cbflood_max; 352 int irq_capable; 353 int can_boost; 354 int extendables; 355 int slow_gps; 356 int no_pi_lock; 357 const char *name; 358 }; 359 360 static struct rcu_torture_ops *cur_ops; 361 362 /* 363 * Definitions for rcu torture testing. 364 */ 365 366 static int torture_readlock_not_held(void) 367 { 368 return rcu_read_lock_bh_held() || rcu_read_lock_sched_held(); 369 } 370 371 static int rcu_torture_read_lock(void) __acquires(RCU) 372 { 373 rcu_read_lock(); 374 return 0; 375 } 376 377 static void 378 rcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp) 379 { 380 unsigned long started; 381 unsigned long completed; 382 const unsigned long shortdelay_us = 200; 383 unsigned long longdelay_ms = 300; 384 unsigned long long ts; 385 386 /* We want a short delay sometimes to make a reader delay the grace 387 * period, and we want a long delay occasionally to trigger 388 * force_quiescent_state. */ 389 390 if (!atomic_read(&rcu_fwd_cb_nodelay) && 391 !(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) { 392 started = cur_ops->get_gp_seq(); 393 ts = rcu_trace_clock_local(); 394 if (preempt_count() & (SOFTIRQ_MASK | HARDIRQ_MASK)) 395 longdelay_ms = 5; /* Avoid triggering BH limits. */ 396 mdelay(longdelay_ms); 397 rtrsp->rt_delay_ms = longdelay_ms; 398 completed = cur_ops->get_gp_seq(); 399 do_trace_rcu_torture_read(cur_ops->name, NULL, ts, 400 started, completed); 401 } 402 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) { 403 udelay(shortdelay_us); 404 rtrsp->rt_delay_us = shortdelay_us; 405 } 406 if (!preempt_count() && 407 !(torture_random(rrsp) % (nrealreaders * 500))) { 408 torture_preempt_schedule(); /* QS only if preemptible. */ 409 rtrsp->rt_preempted = true; 410 } 411 } 412 413 static void rcu_torture_read_unlock(int idx) __releases(RCU) 414 { 415 rcu_read_unlock(); 416 } 417 418 /* 419 * Update callback in the pipe. This should be invoked after a grace period. 420 */ 421 static bool 422 rcu_torture_pipe_update_one(struct rcu_torture *rp) 423 { 424 int i; 425 struct rcu_torture_reader_check *rtrcp = READ_ONCE(rp->rtort_chkp); 426 427 if (rtrcp) { 428 WRITE_ONCE(rp->rtort_chkp, NULL); 429 smp_store_release(&rtrcp->rtc_ready, 1); // Pair with smp_load_acquire(). 430 } 431 i = READ_ONCE(rp->rtort_pipe_count); 432 if (i > RCU_TORTURE_PIPE_LEN) 433 i = RCU_TORTURE_PIPE_LEN; 434 atomic_inc(&rcu_torture_wcount[i]); 435 WRITE_ONCE(rp->rtort_pipe_count, i + 1); 436 if (rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) { 437 rp->rtort_mbtest = 0; 438 return true; 439 } 440 return false; 441 } 442 443 /* 444 * Update all callbacks in the pipe. Suitable for synchronous grace-period 445 * primitives. 446 */ 447 static void 448 rcu_torture_pipe_update(struct rcu_torture *old_rp) 449 { 450 struct rcu_torture *rp; 451 struct rcu_torture *rp1; 452 453 if (old_rp) 454 list_add(&old_rp->rtort_free, &rcu_torture_removed); 455 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) { 456 if (rcu_torture_pipe_update_one(rp)) { 457 list_del(&rp->rtort_free); 458 rcu_torture_free(rp); 459 } 460 } 461 } 462 463 static void 464 rcu_torture_cb(struct rcu_head *p) 465 { 466 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu); 467 468 if (torture_must_stop_irq()) { 469 /* Test is ending, just drop callbacks on the floor. */ 470 /* The next initialization will pick up the pieces. */ 471 return; 472 } 473 if (rcu_torture_pipe_update_one(rp)) 474 rcu_torture_free(rp); 475 else 476 cur_ops->deferred_free(rp); 477 } 478 479 static unsigned long rcu_no_completed(void) 480 { 481 return 0; 482 } 483 484 static void rcu_torture_deferred_free(struct rcu_torture *p) 485 { 486 call_rcu(&p->rtort_rcu, rcu_torture_cb); 487 } 488 489 static void rcu_sync_torture_init(void) 490 { 491 INIT_LIST_HEAD(&rcu_torture_removed); 492 } 493 494 static struct rcu_torture_ops rcu_ops = { 495 .ttype = RCU_FLAVOR, 496 .init = rcu_sync_torture_init, 497 .readlock = rcu_torture_read_lock, 498 .read_delay = rcu_read_delay, 499 .readunlock = rcu_torture_read_unlock, 500 .readlock_held = torture_readlock_not_held, 501 .get_gp_seq = rcu_get_gp_seq, 502 .gp_diff = rcu_seq_diff, 503 .deferred_free = rcu_torture_deferred_free, 504 .sync = synchronize_rcu, 505 .exp_sync = synchronize_rcu_expedited, 506 .get_gp_state = get_state_synchronize_rcu, 507 .start_gp_poll = start_poll_synchronize_rcu, 508 .poll_gp_state = poll_state_synchronize_rcu, 509 .cond_sync = cond_synchronize_rcu, 510 .call = call_rcu, 511 .cb_barrier = rcu_barrier, 512 .fqs = rcu_force_quiescent_state, 513 .stats = NULL, 514 .gp_kthread_dbg = show_rcu_gp_kthreads, 515 .check_boost_failed = rcu_check_boost_fail, 516 .stall_dur = rcu_jiffies_till_stall_check, 517 .irq_capable = 1, 518 .can_boost = IS_ENABLED(CONFIG_RCU_BOOST), 519 .extendables = RCUTORTURE_MAX_EXTEND, 520 .name = "rcu" 521 }; 522 523 /* 524 * Don't even think about trying any of these in real life!!! 525 * The names includes "busted", and they really means it! 526 * The only purpose of these functions is to provide a buggy RCU 527 * implementation to make sure that rcutorture correctly emits 528 * buggy-RCU error messages. 529 */ 530 static void rcu_busted_torture_deferred_free(struct rcu_torture *p) 531 { 532 /* This is a deliberate bug for testing purposes only! */ 533 rcu_torture_cb(&p->rtort_rcu); 534 } 535 536 static void synchronize_rcu_busted(void) 537 { 538 /* This is a deliberate bug for testing purposes only! */ 539 } 540 541 static void 542 call_rcu_busted(struct rcu_head *head, rcu_callback_t func) 543 { 544 /* This is a deliberate bug for testing purposes only! */ 545 func(head); 546 } 547 548 static struct rcu_torture_ops rcu_busted_ops = { 549 .ttype = INVALID_RCU_FLAVOR, 550 .init = rcu_sync_torture_init, 551 .readlock = rcu_torture_read_lock, 552 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 553 .readunlock = rcu_torture_read_unlock, 554 .readlock_held = torture_readlock_not_held, 555 .get_gp_seq = rcu_no_completed, 556 .deferred_free = rcu_busted_torture_deferred_free, 557 .sync = synchronize_rcu_busted, 558 .exp_sync = synchronize_rcu_busted, 559 .call = call_rcu_busted, 560 .cb_barrier = NULL, 561 .fqs = NULL, 562 .stats = NULL, 563 .irq_capable = 1, 564 .name = "busted" 565 }; 566 567 /* 568 * Definitions for srcu torture testing. 569 */ 570 571 DEFINE_STATIC_SRCU(srcu_ctl); 572 static struct srcu_struct srcu_ctld; 573 static struct srcu_struct *srcu_ctlp = &srcu_ctl; 574 575 static int srcu_torture_read_lock(void) __acquires(srcu_ctlp) 576 { 577 return srcu_read_lock(srcu_ctlp); 578 } 579 580 static void 581 srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp) 582 { 583 long delay; 584 const long uspertick = 1000000 / HZ; 585 const long longdelay = 10; 586 587 /* We want there to be long-running readers, but not all the time. */ 588 589 delay = torture_random(rrsp) % 590 (nrealreaders * 2 * longdelay * uspertick); 591 if (!delay && in_task()) { 592 schedule_timeout_interruptible(longdelay); 593 rtrsp->rt_delay_jiffies = longdelay; 594 } else { 595 rcu_read_delay(rrsp, rtrsp); 596 } 597 } 598 599 static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp) 600 { 601 srcu_read_unlock(srcu_ctlp, idx); 602 } 603 604 static int torture_srcu_read_lock_held(void) 605 { 606 return srcu_read_lock_held(srcu_ctlp); 607 } 608 609 static unsigned long srcu_torture_completed(void) 610 { 611 return srcu_batches_completed(srcu_ctlp); 612 } 613 614 static void srcu_torture_deferred_free(struct rcu_torture *rp) 615 { 616 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb); 617 } 618 619 static void srcu_torture_synchronize(void) 620 { 621 synchronize_srcu(srcu_ctlp); 622 } 623 624 static unsigned long srcu_torture_get_gp_state(void) 625 { 626 return get_state_synchronize_srcu(srcu_ctlp); 627 } 628 629 static unsigned long srcu_torture_start_gp_poll(void) 630 { 631 return start_poll_synchronize_srcu(srcu_ctlp); 632 } 633 634 static bool srcu_torture_poll_gp_state(unsigned long oldstate) 635 { 636 return poll_state_synchronize_srcu(srcu_ctlp, oldstate); 637 } 638 639 static void srcu_torture_call(struct rcu_head *head, 640 rcu_callback_t func) 641 { 642 call_srcu(srcu_ctlp, head, func); 643 } 644 645 static void srcu_torture_barrier(void) 646 { 647 srcu_barrier(srcu_ctlp); 648 } 649 650 static void srcu_torture_stats(void) 651 { 652 srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG); 653 } 654 655 static void srcu_torture_synchronize_expedited(void) 656 { 657 synchronize_srcu_expedited(srcu_ctlp); 658 } 659 660 static struct rcu_torture_ops srcu_ops = { 661 .ttype = SRCU_FLAVOR, 662 .init = rcu_sync_torture_init, 663 .readlock = srcu_torture_read_lock, 664 .read_delay = srcu_read_delay, 665 .readunlock = srcu_torture_read_unlock, 666 .readlock_held = torture_srcu_read_lock_held, 667 .get_gp_seq = srcu_torture_completed, 668 .deferred_free = srcu_torture_deferred_free, 669 .sync = srcu_torture_synchronize, 670 .exp_sync = srcu_torture_synchronize_expedited, 671 .get_gp_state = srcu_torture_get_gp_state, 672 .start_gp_poll = srcu_torture_start_gp_poll, 673 .poll_gp_state = srcu_torture_poll_gp_state, 674 .call = srcu_torture_call, 675 .cb_barrier = srcu_torture_barrier, 676 .stats = srcu_torture_stats, 677 .cbflood_max = 50000, 678 .irq_capable = 1, 679 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU), 680 .name = "srcu" 681 }; 682 683 static void srcu_torture_init(void) 684 { 685 rcu_sync_torture_init(); 686 WARN_ON(init_srcu_struct(&srcu_ctld)); 687 srcu_ctlp = &srcu_ctld; 688 } 689 690 static void srcu_torture_cleanup(void) 691 { 692 cleanup_srcu_struct(&srcu_ctld); 693 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */ 694 } 695 696 /* As above, but dynamically allocated. */ 697 static struct rcu_torture_ops srcud_ops = { 698 .ttype = SRCU_FLAVOR, 699 .init = srcu_torture_init, 700 .cleanup = srcu_torture_cleanup, 701 .readlock = srcu_torture_read_lock, 702 .read_delay = srcu_read_delay, 703 .readunlock = srcu_torture_read_unlock, 704 .readlock_held = torture_srcu_read_lock_held, 705 .get_gp_seq = srcu_torture_completed, 706 .deferred_free = srcu_torture_deferred_free, 707 .sync = srcu_torture_synchronize, 708 .exp_sync = srcu_torture_synchronize_expedited, 709 .call = srcu_torture_call, 710 .cb_barrier = srcu_torture_barrier, 711 .stats = srcu_torture_stats, 712 .cbflood_max = 50000, 713 .irq_capable = 1, 714 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU), 715 .name = "srcud" 716 }; 717 718 /* As above, but broken due to inappropriate reader extension. */ 719 static struct rcu_torture_ops busted_srcud_ops = { 720 .ttype = SRCU_FLAVOR, 721 .init = srcu_torture_init, 722 .cleanup = srcu_torture_cleanup, 723 .readlock = srcu_torture_read_lock, 724 .read_delay = rcu_read_delay, 725 .readunlock = srcu_torture_read_unlock, 726 .readlock_held = torture_srcu_read_lock_held, 727 .get_gp_seq = srcu_torture_completed, 728 .deferred_free = srcu_torture_deferred_free, 729 .sync = srcu_torture_synchronize, 730 .exp_sync = srcu_torture_synchronize_expedited, 731 .call = srcu_torture_call, 732 .cb_barrier = srcu_torture_barrier, 733 .stats = srcu_torture_stats, 734 .irq_capable = 1, 735 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU), 736 .extendables = RCUTORTURE_MAX_EXTEND, 737 .name = "busted_srcud" 738 }; 739 740 /* 741 * Definitions for RCU-tasks torture testing. 742 */ 743 744 static int tasks_torture_read_lock(void) 745 { 746 return 0; 747 } 748 749 static void tasks_torture_read_unlock(int idx) 750 { 751 } 752 753 static void rcu_tasks_torture_deferred_free(struct rcu_torture *p) 754 { 755 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb); 756 } 757 758 static void synchronize_rcu_mult_test(void) 759 { 760 synchronize_rcu_mult(call_rcu_tasks, call_rcu); 761 } 762 763 static struct rcu_torture_ops tasks_ops = { 764 .ttype = RCU_TASKS_FLAVOR, 765 .init = rcu_sync_torture_init, 766 .readlock = tasks_torture_read_lock, 767 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 768 .readunlock = tasks_torture_read_unlock, 769 .get_gp_seq = rcu_no_completed, 770 .deferred_free = rcu_tasks_torture_deferred_free, 771 .sync = synchronize_rcu_tasks, 772 .exp_sync = synchronize_rcu_mult_test, 773 .call = call_rcu_tasks, 774 .cb_barrier = rcu_barrier_tasks, 775 .gp_kthread_dbg = show_rcu_tasks_classic_gp_kthread, 776 .fqs = NULL, 777 .stats = NULL, 778 .irq_capable = 1, 779 .slow_gps = 1, 780 .name = "tasks" 781 }; 782 783 /* 784 * Definitions for trivial CONFIG_PREEMPT=n-only torture testing. 785 * This implementation does not necessarily work well with CPU hotplug. 786 */ 787 788 static void synchronize_rcu_trivial(void) 789 { 790 int cpu; 791 792 for_each_online_cpu(cpu) { 793 rcutorture_sched_setaffinity(current->pid, cpumask_of(cpu)); 794 WARN_ON_ONCE(raw_smp_processor_id() != cpu); 795 } 796 } 797 798 static int rcu_torture_read_lock_trivial(void) __acquires(RCU) 799 { 800 preempt_disable(); 801 return 0; 802 } 803 804 static void rcu_torture_read_unlock_trivial(int idx) __releases(RCU) 805 { 806 preempt_enable(); 807 } 808 809 static struct rcu_torture_ops trivial_ops = { 810 .ttype = RCU_TRIVIAL_FLAVOR, 811 .init = rcu_sync_torture_init, 812 .readlock = rcu_torture_read_lock_trivial, 813 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 814 .readunlock = rcu_torture_read_unlock_trivial, 815 .readlock_held = torture_readlock_not_held, 816 .get_gp_seq = rcu_no_completed, 817 .sync = synchronize_rcu_trivial, 818 .exp_sync = synchronize_rcu_trivial, 819 .fqs = NULL, 820 .stats = NULL, 821 .irq_capable = 1, 822 .name = "trivial" 823 }; 824 825 /* 826 * Definitions for rude RCU-tasks torture testing. 827 */ 828 829 static void rcu_tasks_rude_torture_deferred_free(struct rcu_torture *p) 830 { 831 call_rcu_tasks_rude(&p->rtort_rcu, rcu_torture_cb); 832 } 833 834 static struct rcu_torture_ops tasks_rude_ops = { 835 .ttype = RCU_TASKS_RUDE_FLAVOR, 836 .init = rcu_sync_torture_init, 837 .readlock = rcu_torture_read_lock_trivial, 838 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 839 .readunlock = rcu_torture_read_unlock_trivial, 840 .get_gp_seq = rcu_no_completed, 841 .deferred_free = rcu_tasks_rude_torture_deferred_free, 842 .sync = synchronize_rcu_tasks_rude, 843 .exp_sync = synchronize_rcu_tasks_rude, 844 .call = call_rcu_tasks_rude, 845 .cb_barrier = rcu_barrier_tasks_rude, 846 .gp_kthread_dbg = show_rcu_tasks_rude_gp_kthread, 847 .cbflood_max = 50000, 848 .fqs = NULL, 849 .stats = NULL, 850 .irq_capable = 1, 851 .name = "tasks-rude" 852 }; 853 854 /* 855 * Definitions for tracing RCU-tasks torture testing. 856 */ 857 858 static int tasks_tracing_torture_read_lock(void) 859 { 860 rcu_read_lock_trace(); 861 return 0; 862 } 863 864 static void tasks_tracing_torture_read_unlock(int idx) 865 { 866 rcu_read_unlock_trace(); 867 } 868 869 static void rcu_tasks_tracing_torture_deferred_free(struct rcu_torture *p) 870 { 871 call_rcu_tasks_trace(&p->rtort_rcu, rcu_torture_cb); 872 } 873 874 static struct rcu_torture_ops tasks_tracing_ops = { 875 .ttype = RCU_TASKS_TRACING_FLAVOR, 876 .init = rcu_sync_torture_init, 877 .readlock = tasks_tracing_torture_read_lock, 878 .read_delay = srcu_read_delay, /* just reuse srcu's version. */ 879 .readunlock = tasks_tracing_torture_read_unlock, 880 .readlock_held = rcu_read_lock_trace_held, 881 .get_gp_seq = rcu_no_completed, 882 .deferred_free = rcu_tasks_tracing_torture_deferred_free, 883 .sync = synchronize_rcu_tasks_trace, 884 .exp_sync = synchronize_rcu_tasks_trace, 885 .call = call_rcu_tasks_trace, 886 .cb_barrier = rcu_barrier_tasks_trace, 887 .gp_kthread_dbg = show_rcu_tasks_trace_gp_kthread, 888 .cbflood_max = 50000, 889 .fqs = NULL, 890 .stats = NULL, 891 .irq_capable = 1, 892 .slow_gps = 1, 893 .name = "tasks-tracing" 894 }; 895 896 static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old) 897 { 898 if (!cur_ops->gp_diff) 899 return new - old; 900 return cur_ops->gp_diff(new, old); 901 } 902 903 /* 904 * RCU torture priority-boost testing. Runs one real-time thread per 905 * CPU for moderate bursts, repeatedly starting grace periods and waiting 906 * for them to complete. If a given grace period takes too long, we assume 907 * that priority inversion has occurred. 908 */ 909 910 static int old_rt_runtime = -1; 911 912 static void rcu_torture_disable_rt_throttle(void) 913 { 914 /* 915 * Disable RT throttling so that rcutorture's boost threads don't get 916 * throttled. Only possible if rcutorture is built-in otherwise the 917 * user should manually do this by setting the sched_rt_period_us and 918 * sched_rt_runtime sysctls. 919 */ 920 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime != -1) 921 return; 922 923 old_rt_runtime = sysctl_sched_rt_runtime; 924 sysctl_sched_rt_runtime = -1; 925 } 926 927 static void rcu_torture_enable_rt_throttle(void) 928 { 929 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime == -1) 930 return; 931 932 sysctl_sched_rt_runtime = old_rt_runtime; 933 old_rt_runtime = -1; 934 } 935 936 static bool rcu_torture_boost_failed(unsigned long gp_state, unsigned long *start) 937 { 938 int cpu; 939 static int dbg_done; 940 unsigned long end = jiffies; 941 bool gp_done; 942 unsigned long j; 943 static unsigned long last_persist; 944 unsigned long lp; 945 unsigned long mininterval = test_boost_duration * HZ - HZ / 2; 946 947 if (end - *start > mininterval) { 948 // Recheck after checking time to avoid false positives. 949 smp_mb(); // Time check before grace-period check. 950 if (cur_ops->poll_gp_state(gp_state)) 951 return false; // passed, though perhaps just barely 952 if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, &cpu)) { 953 // At most one persisted message per boost test. 954 j = jiffies; 955 lp = READ_ONCE(last_persist); 956 if (time_after(j, lp + mininterval) && cmpxchg(&last_persist, lp, j) == lp) 957 pr_info("Boost inversion persisted: No QS from CPU %d\n", cpu); 958 return false; // passed on a technicality 959 } 960 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed"); 961 n_rcu_torture_boost_failure++; 962 if (!xchg(&dbg_done, 1) && cur_ops->gp_kthread_dbg) { 963 pr_info("Boost inversion thread ->rt_priority %u gp_state %lu jiffies %lu\n", 964 current->rt_priority, gp_state, end - *start); 965 cur_ops->gp_kthread_dbg(); 966 // Recheck after print to flag grace period ending during splat. 967 gp_done = cur_ops->poll_gp_state(gp_state); 968 pr_info("Boost inversion: GP %lu %s.\n", gp_state, 969 gp_done ? "ended already" : "still pending"); 970 971 } 972 973 return true; // failed 974 } else if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, NULL)) { 975 *start = jiffies; 976 } 977 978 return false; // passed 979 } 980 981 static int rcu_torture_boost(void *arg) 982 { 983 unsigned long endtime; 984 unsigned long gp_state; 985 unsigned long gp_state_time; 986 unsigned long oldstarttime; 987 988 VERBOSE_TOROUT_STRING("rcu_torture_boost started"); 989 990 /* Set real-time priority. */ 991 sched_set_fifo_low(current); 992 993 /* Each pass through the following loop does one boost-test cycle. */ 994 do { 995 bool failed = false; // Test failed already in this test interval 996 bool gp_initiated = false; 997 998 if (kthread_should_stop()) 999 goto checkwait; 1000 1001 /* Wait for the next test interval. */ 1002 oldstarttime = READ_ONCE(boost_starttime); 1003 while (time_before(jiffies, oldstarttime)) { 1004 schedule_timeout_interruptible(oldstarttime - jiffies); 1005 if (stutter_wait("rcu_torture_boost")) 1006 sched_set_fifo_low(current); 1007 if (torture_must_stop()) 1008 goto checkwait; 1009 } 1010 1011 // Do one boost-test interval. 1012 endtime = oldstarttime + test_boost_duration * HZ; 1013 while (time_before(jiffies, endtime)) { 1014 // Has current GP gone too long? 1015 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state)) 1016 failed = rcu_torture_boost_failed(gp_state, &gp_state_time); 1017 // If we don't have a grace period in flight, start one. 1018 if (!gp_initiated || cur_ops->poll_gp_state(gp_state)) { 1019 gp_state = cur_ops->start_gp_poll(); 1020 gp_initiated = true; 1021 gp_state_time = jiffies; 1022 } 1023 if (stutter_wait("rcu_torture_boost")) { 1024 sched_set_fifo_low(current); 1025 // If the grace period already ended, 1026 // we don't know when that happened, so 1027 // start over. 1028 if (cur_ops->poll_gp_state(gp_state)) 1029 gp_initiated = false; 1030 } 1031 if (torture_must_stop()) 1032 goto checkwait; 1033 } 1034 1035 // In case the grace period extended beyond the end of the loop. 1036 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state)) 1037 rcu_torture_boost_failed(gp_state, &gp_state_time); 1038 1039 /* 1040 * Set the start time of the next test interval. 1041 * Yes, this is vulnerable to long delays, but such 1042 * delays simply cause a false negative for the next 1043 * interval. Besides, we are running at RT priority, 1044 * so delays should be relatively rare. 1045 */ 1046 while (oldstarttime == READ_ONCE(boost_starttime) && !kthread_should_stop()) { 1047 if (mutex_trylock(&boost_mutex)) { 1048 if (oldstarttime == boost_starttime) { 1049 WRITE_ONCE(boost_starttime, 1050 jiffies + test_boost_interval * HZ); 1051 n_rcu_torture_boosts++; 1052 } 1053 mutex_unlock(&boost_mutex); 1054 break; 1055 } 1056 schedule_timeout_uninterruptible(1); 1057 } 1058 1059 /* Go do the stutter. */ 1060 checkwait: if (stutter_wait("rcu_torture_boost")) 1061 sched_set_fifo_low(current); 1062 } while (!torture_must_stop()); 1063 1064 /* Clean up and exit. */ 1065 while (!kthread_should_stop()) { 1066 torture_shutdown_absorb("rcu_torture_boost"); 1067 schedule_timeout_uninterruptible(1); 1068 } 1069 torture_kthread_stopping("rcu_torture_boost"); 1070 return 0; 1071 } 1072 1073 /* 1074 * RCU torture force-quiescent-state kthread. Repeatedly induces 1075 * bursts of calls to force_quiescent_state(), increasing the probability 1076 * of occurrence of some important types of race conditions. 1077 */ 1078 static int 1079 rcu_torture_fqs(void *arg) 1080 { 1081 unsigned long fqs_resume_time; 1082 int fqs_burst_remaining; 1083 int oldnice = task_nice(current); 1084 1085 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started"); 1086 do { 1087 fqs_resume_time = jiffies + fqs_stutter * HZ; 1088 while (time_before(jiffies, fqs_resume_time) && 1089 !kthread_should_stop()) { 1090 schedule_timeout_interruptible(1); 1091 } 1092 fqs_burst_remaining = fqs_duration; 1093 while (fqs_burst_remaining > 0 && 1094 !kthread_should_stop()) { 1095 cur_ops->fqs(); 1096 udelay(fqs_holdoff); 1097 fqs_burst_remaining -= fqs_holdoff; 1098 } 1099 if (stutter_wait("rcu_torture_fqs")) 1100 sched_set_normal(current, oldnice); 1101 } while (!torture_must_stop()); 1102 torture_kthread_stopping("rcu_torture_fqs"); 1103 return 0; 1104 } 1105 1106 // Used by writers to randomly choose from the available grace-period 1107 // primitives. The only purpose of the initialization is to size the array. 1108 static int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC, RTWS_COND_GET, RTWS_POLL_GET, RTWS_SYNC }; 1109 static int nsynctypes; 1110 1111 /* 1112 * Determine which grace-period primitives are available. 1113 */ 1114 static void rcu_torture_write_types(void) 1115 { 1116 bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal; 1117 bool gp_poll1 = gp_poll, gp_sync1 = gp_sync; 1118 1119 /* Initialize synctype[] array. If none set, take default. */ 1120 if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_poll1 && !gp_sync1) 1121 gp_cond1 = gp_exp1 = gp_normal1 = gp_poll1 = gp_sync1 = true; 1122 if (gp_cond1 && cur_ops->get_gp_state && cur_ops->cond_sync) { 1123 synctype[nsynctypes++] = RTWS_COND_GET; 1124 pr_info("%s: Testing conditional GPs.\n", __func__); 1125 } else if (gp_cond && (!cur_ops->get_gp_state || !cur_ops->cond_sync)) { 1126 pr_alert("%s: gp_cond without primitives.\n", __func__); 1127 } 1128 if (gp_exp1 && cur_ops->exp_sync) { 1129 synctype[nsynctypes++] = RTWS_EXP_SYNC; 1130 pr_info("%s: Testing expedited GPs.\n", __func__); 1131 } else if (gp_exp && !cur_ops->exp_sync) { 1132 pr_alert("%s: gp_exp without primitives.\n", __func__); 1133 } 1134 if (gp_normal1 && cur_ops->deferred_free) { 1135 synctype[nsynctypes++] = RTWS_DEF_FREE; 1136 pr_info("%s: Testing asynchronous GPs.\n", __func__); 1137 } else if (gp_normal && !cur_ops->deferred_free) { 1138 pr_alert("%s: gp_normal without primitives.\n", __func__); 1139 } 1140 if (gp_poll1 && cur_ops->start_gp_poll && cur_ops->poll_gp_state) { 1141 synctype[nsynctypes++] = RTWS_POLL_GET; 1142 pr_info("%s: Testing polling GPs.\n", __func__); 1143 } else if (gp_poll && (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)) { 1144 pr_alert("%s: gp_poll without primitives.\n", __func__); 1145 } 1146 if (gp_sync1 && cur_ops->sync) { 1147 synctype[nsynctypes++] = RTWS_SYNC; 1148 pr_info("%s: Testing normal GPs.\n", __func__); 1149 } else if (gp_sync && !cur_ops->sync) { 1150 pr_alert("%s: gp_sync without primitives.\n", __func__); 1151 } 1152 } 1153 1154 /* 1155 * RCU torture writer kthread. Repeatedly substitutes a new structure 1156 * for that pointed to by rcu_torture_current, freeing the old structure 1157 * after a series of grace periods (the "pipeline"). 1158 */ 1159 static int 1160 rcu_torture_writer(void *arg) 1161 { 1162 bool boot_ended; 1163 bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal(); 1164 unsigned long cookie; 1165 int expediting = 0; 1166 unsigned long gp_snap; 1167 int i; 1168 int idx; 1169 int oldnice = task_nice(current); 1170 struct rcu_torture *rp; 1171 struct rcu_torture *old_rp; 1172 static DEFINE_TORTURE_RANDOM(rand); 1173 bool stutter_waited; 1174 1175 VERBOSE_TOROUT_STRING("rcu_torture_writer task started"); 1176 if (!can_expedite) 1177 pr_alert("%s" TORTURE_FLAG 1178 " GP expediting controlled from boot/sysfs for %s.\n", 1179 torture_type, cur_ops->name); 1180 if (WARN_ONCE(nsynctypes == 0, 1181 "rcu_torture_writer: No update-side primitives.\n")) { 1182 /* 1183 * No updates primitives, so don't try updating. 1184 * The resulting test won't be testing much, hence the 1185 * above WARN_ONCE(). 1186 */ 1187 rcu_torture_writer_state = RTWS_STOPPING; 1188 torture_kthread_stopping("rcu_torture_writer"); 1189 } 1190 1191 do { 1192 rcu_torture_writer_state = RTWS_FIXED_DELAY; 1193 torture_hrtimeout_us(500, 1000, &rand); 1194 rp = rcu_torture_alloc(); 1195 if (rp == NULL) 1196 continue; 1197 rp->rtort_pipe_count = 0; 1198 rcu_torture_writer_state = RTWS_DELAY; 1199 udelay(torture_random(&rand) & 0x3ff); 1200 rcu_torture_writer_state = RTWS_REPLACE; 1201 old_rp = rcu_dereference_check(rcu_torture_current, 1202 current == writer_task); 1203 rp->rtort_mbtest = 1; 1204 rcu_assign_pointer(rcu_torture_current, rp); 1205 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */ 1206 if (old_rp) { 1207 i = old_rp->rtort_pipe_count; 1208 if (i > RCU_TORTURE_PIPE_LEN) 1209 i = RCU_TORTURE_PIPE_LEN; 1210 atomic_inc(&rcu_torture_wcount[i]); 1211 WRITE_ONCE(old_rp->rtort_pipe_count, 1212 old_rp->rtort_pipe_count + 1); 1213 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) { 1214 idx = cur_ops->readlock(); 1215 cookie = cur_ops->get_gp_state(); 1216 WARN_ONCE(rcu_torture_writer_state != RTWS_DEF_FREE && 1217 cur_ops->poll_gp_state(cookie), 1218 "%s: Cookie check 1 failed %s(%d) %lu->%lu\n", 1219 __func__, 1220 rcu_torture_writer_state_getname(), 1221 rcu_torture_writer_state, 1222 cookie, cur_ops->get_gp_state()); 1223 cur_ops->readunlock(idx); 1224 } 1225 switch (synctype[torture_random(&rand) % nsynctypes]) { 1226 case RTWS_DEF_FREE: 1227 rcu_torture_writer_state = RTWS_DEF_FREE; 1228 cur_ops->deferred_free(old_rp); 1229 break; 1230 case RTWS_EXP_SYNC: 1231 rcu_torture_writer_state = RTWS_EXP_SYNC; 1232 cur_ops->exp_sync(); 1233 rcu_torture_pipe_update(old_rp); 1234 break; 1235 case RTWS_COND_GET: 1236 rcu_torture_writer_state = RTWS_COND_GET; 1237 gp_snap = cur_ops->get_gp_state(); 1238 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); 1239 rcu_torture_writer_state = RTWS_COND_SYNC; 1240 cur_ops->cond_sync(gp_snap); 1241 rcu_torture_pipe_update(old_rp); 1242 break; 1243 case RTWS_POLL_GET: 1244 rcu_torture_writer_state = RTWS_POLL_GET; 1245 gp_snap = cur_ops->start_gp_poll(); 1246 rcu_torture_writer_state = RTWS_POLL_WAIT; 1247 while (!cur_ops->poll_gp_state(gp_snap)) 1248 torture_hrtimeout_jiffies(torture_random(&rand) % 16, 1249 &rand); 1250 rcu_torture_pipe_update(old_rp); 1251 break; 1252 case RTWS_SYNC: 1253 rcu_torture_writer_state = RTWS_SYNC; 1254 cur_ops->sync(); 1255 rcu_torture_pipe_update(old_rp); 1256 break; 1257 default: 1258 WARN_ON_ONCE(1); 1259 break; 1260 } 1261 } 1262 WRITE_ONCE(rcu_torture_current_version, 1263 rcu_torture_current_version + 1); 1264 /* Cycle through nesting levels of rcu_expedite_gp() calls. */ 1265 if (can_expedite && 1266 !(torture_random(&rand) & 0xff & (!!expediting - 1))) { 1267 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited()); 1268 if (expediting >= 0) 1269 rcu_expedite_gp(); 1270 else 1271 rcu_unexpedite_gp(); 1272 if (++expediting > 3) 1273 expediting = -expediting; 1274 } else if (!can_expedite) { /* Disabled during boot, recheck. */ 1275 can_expedite = !rcu_gp_is_expedited() && 1276 !rcu_gp_is_normal(); 1277 } 1278 rcu_torture_writer_state = RTWS_STUTTER; 1279 boot_ended = rcu_inkernel_boot_has_ended(); 1280 stutter_waited = stutter_wait("rcu_torture_writer"); 1281 if (stutter_waited && 1282 !atomic_read(&rcu_fwd_cb_nodelay) && 1283 !cur_ops->slow_gps && 1284 !torture_must_stop() && 1285 boot_ended) 1286 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) 1287 if (list_empty(&rcu_tortures[i].rtort_free) && 1288 rcu_access_pointer(rcu_torture_current) != 1289 &rcu_tortures[i]) { 1290 rcu_ftrace_dump(DUMP_ALL); 1291 WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count); 1292 } 1293 if (stutter_waited) 1294 sched_set_normal(current, oldnice); 1295 } while (!torture_must_stop()); 1296 rcu_torture_current = NULL; // Let stats task know that we are done. 1297 /* Reset expediting back to unexpedited. */ 1298 if (expediting > 0) 1299 expediting = -expediting; 1300 while (can_expedite && expediting++ < 0) 1301 rcu_unexpedite_gp(); 1302 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited()); 1303 if (!can_expedite) 1304 pr_alert("%s" TORTURE_FLAG 1305 " Dynamic grace-period expediting was disabled.\n", 1306 torture_type); 1307 rcu_torture_writer_state = RTWS_STOPPING; 1308 torture_kthread_stopping("rcu_torture_writer"); 1309 return 0; 1310 } 1311 1312 /* 1313 * RCU torture fake writer kthread. Repeatedly calls sync, with a random 1314 * delay between calls. 1315 */ 1316 static int 1317 rcu_torture_fakewriter(void *arg) 1318 { 1319 unsigned long gp_snap; 1320 DEFINE_TORTURE_RANDOM(rand); 1321 1322 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started"); 1323 set_user_nice(current, MAX_NICE); 1324 1325 do { 1326 torture_hrtimeout_jiffies(torture_random(&rand) % 10, &rand); 1327 if (cur_ops->cb_barrier != NULL && 1328 torture_random(&rand) % (nfakewriters * 8) == 0) { 1329 cur_ops->cb_barrier(); 1330 } else { 1331 switch (synctype[torture_random(&rand) % nsynctypes]) { 1332 case RTWS_DEF_FREE: 1333 break; 1334 case RTWS_EXP_SYNC: 1335 cur_ops->exp_sync(); 1336 break; 1337 case RTWS_COND_GET: 1338 gp_snap = cur_ops->get_gp_state(); 1339 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); 1340 cur_ops->cond_sync(gp_snap); 1341 break; 1342 case RTWS_POLL_GET: 1343 gp_snap = cur_ops->start_gp_poll(); 1344 while (!cur_ops->poll_gp_state(gp_snap)) { 1345 torture_hrtimeout_jiffies(torture_random(&rand) % 16, 1346 &rand); 1347 } 1348 break; 1349 case RTWS_SYNC: 1350 cur_ops->sync(); 1351 break; 1352 default: 1353 WARN_ON_ONCE(1); 1354 break; 1355 } 1356 } 1357 stutter_wait("rcu_torture_fakewriter"); 1358 } while (!torture_must_stop()); 1359 1360 torture_kthread_stopping("rcu_torture_fakewriter"); 1361 return 0; 1362 } 1363 1364 static void rcu_torture_timer_cb(struct rcu_head *rhp) 1365 { 1366 kfree(rhp); 1367 } 1368 1369 // Set up and carry out testing of RCU's global memory ordering 1370 static void rcu_torture_reader_do_mbchk(long myid, struct rcu_torture *rtp, 1371 struct torture_random_state *trsp) 1372 { 1373 unsigned long loops; 1374 int noc = torture_num_online_cpus(); 1375 int rdrchked; 1376 int rdrchker; 1377 struct rcu_torture_reader_check *rtrcp; // Me. 1378 struct rcu_torture_reader_check *rtrcp_assigner; // Assigned us to do checking. 1379 struct rcu_torture_reader_check *rtrcp_chked; // Reader being checked. 1380 struct rcu_torture_reader_check *rtrcp_chker; // Reader doing checking when not me. 1381 1382 if (myid < 0) 1383 return; // Don't try this from timer handlers. 1384 1385 // Increment my counter. 1386 rtrcp = &rcu_torture_reader_mbchk[myid]; 1387 WRITE_ONCE(rtrcp->rtc_myloops, rtrcp->rtc_myloops + 1); 1388 1389 // Attempt to assign someone else some checking work. 1390 rdrchked = torture_random(trsp) % nrealreaders; 1391 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked]; 1392 rdrchker = torture_random(trsp) % nrealreaders; 1393 rtrcp_chker = &rcu_torture_reader_mbchk[rdrchker]; 1394 if (rdrchked != myid && rdrchked != rdrchker && noc >= rdrchked && noc >= rdrchker && 1395 smp_load_acquire(&rtrcp->rtc_chkrdr) < 0 && // Pairs with smp_store_release below. 1396 !READ_ONCE(rtp->rtort_chkp) && 1397 !smp_load_acquire(&rtrcp_chker->rtc_assigner)) { // Pairs with smp_store_release below. 1398 rtrcp->rtc_chkloops = READ_ONCE(rtrcp_chked->rtc_myloops); 1399 WARN_ON_ONCE(rtrcp->rtc_chkrdr >= 0); 1400 rtrcp->rtc_chkrdr = rdrchked; 1401 WARN_ON_ONCE(rtrcp->rtc_ready); // This gets set after the grace period ends. 1402 if (cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, NULL, rtrcp) || 1403 cmpxchg_relaxed(&rtp->rtort_chkp, NULL, rtrcp)) 1404 (void)cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, rtrcp, NULL); // Back out. 1405 } 1406 1407 // If assigned some completed work, do it! 1408 rtrcp_assigner = READ_ONCE(rtrcp->rtc_assigner); 1409 if (!rtrcp_assigner || !smp_load_acquire(&rtrcp_assigner->rtc_ready)) 1410 return; // No work or work not yet ready. 1411 rdrchked = rtrcp_assigner->rtc_chkrdr; 1412 if (WARN_ON_ONCE(rdrchked < 0)) 1413 return; 1414 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked]; 1415 loops = READ_ONCE(rtrcp_chked->rtc_myloops); 1416 atomic_inc(&n_rcu_torture_mbchk_tries); 1417 if (ULONG_CMP_LT(loops, rtrcp_assigner->rtc_chkloops)) 1418 atomic_inc(&n_rcu_torture_mbchk_fail); 1419 rtrcp_assigner->rtc_chkloops = loops + ULONG_MAX / 2; 1420 rtrcp_assigner->rtc_ready = 0; 1421 smp_store_release(&rtrcp->rtc_assigner, NULL); // Someone else can assign us work. 1422 smp_store_release(&rtrcp_assigner->rtc_chkrdr, -1); // Assigner can again assign. 1423 } 1424 1425 /* 1426 * Do one extension of an RCU read-side critical section using the 1427 * current reader state in readstate (set to zero for initial entry 1428 * to extended critical section), set the new state as specified by 1429 * newstate (set to zero for final exit from extended critical section), 1430 * and random-number-generator state in trsp. If this is neither the 1431 * beginning or end of the critical section and if there was actually a 1432 * change, do a ->read_delay(). 1433 */ 1434 static void rcutorture_one_extend(int *readstate, int newstate, 1435 struct torture_random_state *trsp, 1436 struct rt_read_seg *rtrsp) 1437 { 1438 unsigned long flags; 1439 int idxnew1 = -1; 1440 int idxnew2 = -1; 1441 int idxold1 = *readstate; 1442 int idxold2 = idxold1; 1443 int statesnew = ~*readstate & newstate; 1444 int statesold = *readstate & ~newstate; 1445 1446 WARN_ON_ONCE(idxold2 < 0); 1447 WARN_ON_ONCE((idxold2 >> RCUTORTURE_RDR_SHIFT_2) > 1); 1448 rtrsp->rt_readstate = newstate; 1449 1450 /* First, put new protection in place to avoid critical-section gap. */ 1451 if (statesnew & RCUTORTURE_RDR_BH) 1452 local_bh_disable(); 1453 if (statesnew & RCUTORTURE_RDR_RBH) 1454 rcu_read_lock_bh(); 1455 if (statesnew & RCUTORTURE_RDR_IRQ) 1456 local_irq_disable(); 1457 if (statesnew & RCUTORTURE_RDR_PREEMPT) 1458 preempt_disable(); 1459 if (statesnew & RCUTORTURE_RDR_SCHED) 1460 rcu_read_lock_sched(); 1461 if (statesnew & RCUTORTURE_RDR_RCU_1) 1462 idxnew1 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_1; 1463 if (statesnew & RCUTORTURE_RDR_RCU_2) 1464 idxnew2 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_2; 1465 1466 /* 1467 * Next, remove old protection, in decreasing order of strength 1468 * to avoid unlock paths that aren't safe in the stronger 1469 * context. Namely: BH can not be enabled with disabled interrupts. 1470 * Additionally PREEMPT_RT requires that BH is enabled in preemptible 1471 * context. 1472 */ 1473 if (statesold & RCUTORTURE_RDR_IRQ) 1474 local_irq_enable(); 1475 if (statesold & RCUTORTURE_RDR_PREEMPT) 1476 preempt_enable(); 1477 if (statesold & RCUTORTURE_RDR_SCHED) 1478 rcu_read_unlock_sched(); 1479 if (statesold & RCUTORTURE_RDR_BH) 1480 local_bh_enable(); 1481 if (statesold & RCUTORTURE_RDR_RBH) 1482 rcu_read_unlock_bh(); 1483 if (statesold & RCUTORTURE_RDR_RCU_2) { 1484 cur_ops->readunlock((idxold2 >> RCUTORTURE_RDR_SHIFT_2) & 0x1); 1485 WARN_ON_ONCE(idxnew2 != -1); 1486 idxold2 = 0; 1487 } 1488 if (statesold & RCUTORTURE_RDR_RCU_1) { 1489 bool lockit; 1490 1491 lockit = !cur_ops->no_pi_lock && !statesnew && !(torture_random(trsp) & 0xffff); 1492 if (lockit) 1493 raw_spin_lock_irqsave(¤t->pi_lock, flags); 1494 cur_ops->readunlock((idxold1 >> RCUTORTURE_RDR_SHIFT_1) & 0x1); 1495 WARN_ON_ONCE(idxnew1 != -1); 1496 idxold1 = 0; 1497 if (lockit) 1498 raw_spin_unlock_irqrestore(¤t->pi_lock, flags); 1499 } 1500 1501 /* Delay if neither beginning nor end and there was a change. */ 1502 if ((statesnew || statesold) && *readstate && newstate) 1503 cur_ops->read_delay(trsp, rtrsp); 1504 1505 /* Update the reader state. */ 1506 if (idxnew1 == -1) 1507 idxnew1 = idxold1 & RCUTORTURE_RDR_MASK_1; 1508 WARN_ON_ONCE(idxnew1 < 0); 1509 if (WARN_ON_ONCE((idxnew1 >> RCUTORTURE_RDR_SHIFT_1) > 1)) 1510 pr_info("Unexpected idxnew1 value of %#x\n", idxnew1); 1511 if (idxnew2 == -1) 1512 idxnew2 = idxold2 & RCUTORTURE_RDR_MASK_2; 1513 WARN_ON_ONCE(idxnew2 < 0); 1514 WARN_ON_ONCE((idxnew2 >> RCUTORTURE_RDR_SHIFT_2) > 1); 1515 *readstate = idxnew1 | idxnew2 | newstate; 1516 WARN_ON_ONCE(*readstate < 0); 1517 if (WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT_2) > 1)) 1518 pr_info("Unexpected idxnew2 value of %#x\n", idxnew2); 1519 } 1520 1521 /* Return the biggest extendables mask given current RCU and boot parameters. */ 1522 static int rcutorture_extend_mask_max(void) 1523 { 1524 int mask; 1525 1526 WARN_ON_ONCE(extendables & ~RCUTORTURE_MAX_EXTEND); 1527 mask = extendables & RCUTORTURE_MAX_EXTEND & cur_ops->extendables; 1528 mask = mask | RCUTORTURE_RDR_RCU_1 | RCUTORTURE_RDR_RCU_2; 1529 return mask; 1530 } 1531 1532 /* Return a random protection state mask, but with at least one bit set. */ 1533 static int 1534 rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp) 1535 { 1536 int mask = rcutorture_extend_mask_max(); 1537 unsigned long randmask1 = torture_random(trsp) >> 8; 1538 unsigned long randmask2 = randmask1 >> 3; 1539 unsigned long preempts = RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED; 1540 unsigned long preempts_irq = preempts | RCUTORTURE_RDR_IRQ; 1541 unsigned long bhs = RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH; 1542 1543 WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT_1); 1544 /* Mostly only one bit (need preemption!), sometimes lots of bits. */ 1545 if (!(randmask1 & 0x7)) 1546 mask = mask & randmask2; 1547 else 1548 mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS)); 1549 1550 // Can't have nested RCU reader without outer RCU reader. 1551 if (!(mask & RCUTORTURE_RDR_RCU_1) && (mask & RCUTORTURE_RDR_RCU_2)) { 1552 if (oldmask & RCUTORTURE_RDR_RCU_1) 1553 mask &= ~RCUTORTURE_RDR_RCU_2; 1554 else 1555 mask |= RCUTORTURE_RDR_RCU_1; 1556 } 1557 1558 /* 1559 * Can't enable bh w/irq disabled. 1560 */ 1561 if (mask & RCUTORTURE_RDR_IRQ) 1562 mask |= oldmask & bhs; 1563 1564 /* 1565 * Ideally these sequences would be detected in debug builds 1566 * (regardless of RT), but until then don't stop testing 1567 * them on non-RT. 1568 */ 1569 if (IS_ENABLED(CONFIG_PREEMPT_RT)) { 1570 /* Can't modify BH in atomic context */ 1571 if (oldmask & preempts_irq) 1572 mask &= ~bhs; 1573 if ((oldmask | mask) & preempts_irq) 1574 mask |= oldmask & bhs; 1575 } 1576 1577 return mask ?: RCUTORTURE_RDR_RCU_1; 1578 } 1579 1580 /* 1581 * Do a randomly selected number of extensions of an existing RCU read-side 1582 * critical section. 1583 */ 1584 static struct rt_read_seg * 1585 rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp, 1586 struct rt_read_seg *rtrsp) 1587 { 1588 int i; 1589 int j; 1590 int mask = rcutorture_extend_mask_max(); 1591 1592 WARN_ON_ONCE(!*readstate); /* -Existing- RCU read-side critsect! */ 1593 if (!((mask - 1) & mask)) 1594 return rtrsp; /* Current RCU reader not extendable. */ 1595 /* Bias towards larger numbers of loops. */ 1596 i = (torture_random(trsp) >> 3); 1597 i = ((i | (i >> 3)) & RCUTORTURE_RDR_MAX_LOOPS) + 1; 1598 for (j = 0; j < i; j++) { 1599 mask = rcutorture_extend_mask(*readstate, trsp); 1600 rcutorture_one_extend(readstate, mask, trsp, &rtrsp[j]); 1601 } 1602 return &rtrsp[j]; 1603 } 1604 1605 /* 1606 * Do one read-side critical section, returning false if there was 1607 * no data to read. Can be invoked both from process context and 1608 * from a timer handler. 1609 */ 1610 static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid) 1611 { 1612 unsigned long cookie; 1613 int i; 1614 unsigned long started; 1615 unsigned long completed; 1616 int newstate; 1617 struct rcu_torture *p; 1618 int pipe_count; 1619 int readstate = 0; 1620 struct rt_read_seg rtseg[RCUTORTURE_RDR_MAX_SEGS] = { { 0 } }; 1621 struct rt_read_seg *rtrsp = &rtseg[0]; 1622 struct rt_read_seg *rtrsp1; 1623 unsigned long long ts; 1624 1625 WARN_ON_ONCE(!rcu_is_watching()); 1626 newstate = rcutorture_extend_mask(readstate, trsp); 1627 rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++); 1628 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) 1629 cookie = cur_ops->get_gp_state(); 1630 started = cur_ops->get_gp_seq(); 1631 ts = rcu_trace_clock_local(); 1632 p = rcu_dereference_check(rcu_torture_current, 1633 !cur_ops->readlock_held || cur_ops->readlock_held()); 1634 if (p == NULL) { 1635 /* Wait for rcu_torture_writer to get underway */ 1636 rcutorture_one_extend(&readstate, 0, trsp, rtrsp); 1637 return false; 1638 } 1639 if (p->rtort_mbtest == 0) 1640 atomic_inc(&n_rcu_torture_mberror); 1641 rcu_torture_reader_do_mbchk(myid, p, trsp); 1642 rtrsp = rcutorture_loop_extend(&readstate, trsp, rtrsp); 1643 preempt_disable(); 1644 pipe_count = READ_ONCE(p->rtort_pipe_count); 1645 if (pipe_count > RCU_TORTURE_PIPE_LEN) { 1646 /* Should not happen, but... */ 1647 pipe_count = RCU_TORTURE_PIPE_LEN; 1648 } 1649 completed = cur_ops->get_gp_seq(); 1650 if (pipe_count > 1) { 1651 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, 1652 ts, started, completed); 1653 rcu_ftrace_dump(DUMP_ALL); 1654 } 1655 __this_cpu_inc(rcu_torture_count[pipe_count]); 1656 completed = rcutorture_seq_diff(completed, started); 1657 if (completed > RCU_TORTURE_PIPE_LEN) { 1658 /* Should not happen, but... */ 1659 completed = RCU_TORTURE_PIPE_LEN; 1660 } 1661 __this_cpu_inc(rcu_torture_batch[completed]); 1662 preempt_enable(); 1663 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) 1664 WARN_ONCE(cur_ops->poll_gp_state(cookie), 1665 "%s: Cookie check 2 failed %s(%d) %lu->%lu\n", 1666 __func__, 1667 rcu_torture_writer_state_getname(), 1668 rcu_torture_writer_state, 1669 cookie, cur_ops->get_gp_state()); 1670 rcutorture_one_extend(&readstate, 0, trsp, rtrsp); 1671 WARN_ON_ONCE(readstate); 1672 // This next splat is expected behavior if leakpointer, especially 1673 // for CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels. 1674 WARN_ON_ONCE(leakpointer && READ_ONCE(p->rtort_pipe_count) > 1); 1675 1676 /* If error or close call, record the sequence of reader protections. */ 1677 if ((pipe_count > 1 || completed > 1) && !xchg(&err_segs_recorded, 1)) { 1678 i = 0; 1679 for (rtrsp1 = &rtseg[0]; rtrsp1 < rtrsp; rtrsp1++) 1680 err_segs[i++] = *rtrsp1; 1681 rt_read_nsegs = i; 1682 } 1683 1684 return true; 1685 } 1686 1687 static DEFINE_TORTURE_RANDOM_PERCPU(rcu_torture_timer_rand); 1688 1689 /* 1690 * RCU torture reader from timer handler. Dereferences rcu_torture_current, 1691 * incrementing the corresponding element of the pipeline array. The 1692 * counter in the element should never be greater than 1, otherwise, the 1693 * RCU implementation is broken. 1694 */ 1695 static void rcu_torture_timer(struct timer_list *unused) 1696 { 1697 atomic_long_inc(&n_rcu_torture_timers); 1698 (void)rcu_torture_one_read(this_cpu_ptr(&rcu_torture_timer_rand), -1); 1699 1700 /* Test call_rcu() invocation from interrupt handler. */ 1701 if (cur_ops->call) { 1702 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT); 1703 1704 if (rhp) 1705 cur_ops->call(rhp, rcu_torture_timer_cb); 1706 } 1707 } 1708 1709 /* 1710 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current, 1711 * incrementing the corresponding element of the pipeline array. The 1712 * counter in the element should never be greater than 1, otherwise, the 1713 * RCU implementation is broken. 1714 */ 1715 static int 1716 rcu_torture_reader(void *arg) 1717 { 1718 unsigned long lastsleep = jiffies; 1719 long myid = (long)arg; 1720 int mynumonline = myid; 1721 DEFINE_TORTURE_RANDOM(rand); 1722 struct timer_list t; 1723 1724 VERBOSE_TOROUT_STRING("rcu_torture_reader task started"); 1725 set_user_nice(current, MAX_NICE); 1726 if (irqreader && cur_ops->irq_capable) 1727 timer_setup_on_stack(&t, rcu_torture_timer, 0); 1728 tick_dep_set_task(current, TICK_DEP_BIT_RCU); 1729 do { 1730 if (irqreader && cur_ops->irq_capable) { 1731 if (!timer_pending(&t)) 1732 mod_timer(&t, jiffies + 1); 1733 } 1734 if (!rcu_torture_one_read(&rand, myid) && !torture_must_stop()) 1735 schedule_timeout_interruptible(HZ); 1736 if (time_after(jiffies, lastsleep) && !torture_must_stop()) { 1737 torture_hrtimeout_us(500, 1000, &rand); 1738 lastsleep = jiffies + 10; 1739 } 1740 while (torture_num_online_cpus() < mynumonline && !torture_must_stop()) 1741 schedule_timeout_interruptible(HZ / 5); 1742 stutter_wait("rcu_torture_reader"); 1743 } while (!torture_must_stop()); 1744 if (irqreader && cur_ops->irq_capable) { 1745 del_timer_sync(&t); 1746 destroy_timer_on_stack(&t); 1747 } 1748 tick_dep_clear_task(current, TICK_DEP_BIT_RCU); 1749 torture_kthread_stopping("rcu_torture_reader"); 1750 return 0; 1751 } 1752 1753 /* 1754 * Randomly Toggle CPUs' callback-offload state. This uses hrtimers to 1755 * increase race probabilities and fuzzes the interval between toggling. 1756 */ 1757 static int rcu_nocb_toggle(void *arg) 1758 { 1759 int cpu; 1760 int maxcpu = -1; 1761 int oldnice = task_nice(current); 1762 long r; 1763 DEFINE_TORTURE_RANDOM(rand); 1764 ktime_t toggle_delay; 1765 unsigned long toggle_fuzz; 1766 ktime_t toggle_interval = ms_to_ktime(nocbs_toggle); 1767 1768 VERBOSE_TOROUT_STRING("rcu_nocb_toggle task started"); 1769 while (!rcu_inkernel_boot_has_ended()) 1770 schedule_timeout_interruptible(HZ / 10); 1771 for_each_online_cpu(cpu) 1772 maxcpu = cpu; 1773 WARN_ON(maxcpu < 0); 1774 if (toggle_interval > ULONG_MAX) 1775 toggle_fuzz = ULONG_MAX >> 3; 1776 else 1777 toggle_fuzz = toggle_interval >> 3; 1778 if (toggle_fuzz <= 0) 1779 toggle_fuzz = NSEC_PER_USEC; 1780 do { 1781 r = torture_random(&rand); 1782 cpu = (r >> 4) % (maxcpu + 1); 1783 if (r & 0x1) { 1784 rcu_nocb_cpu_offload(cpu); 1785 atomic_long_inc(&n_nocb_offload); 1786 } else { 1787 rcu_nocb_cpu_deoffload(cpu); 1788 atomic_long_inc(&n_nocb_deoffload); 1789 } 1790 toggle_delay = torture_random(&rand) % toggle_fuzz + toggle_interval; 1791 set_current_state(TASK_INTERRUPTIBLE); 1792 schedule_hrtimeout(&toggle_delay, HRTIMER_MODE_REL); 1793 if (stutter_wait("rcu_nocb_toggle")) 1794 sched_set_normal(current, oldnice); 1795 } while (!torture_must_stop()); 1796 torture_kthread_stopping("rcu_nocb_toggle"); 1797 return 0; 1798 } 1799 1800 /* 1801 * Print torture statistics. Caller must ensure that there is only 1802 * one call to this function at a given time!!! This is normally 1803 * accomplished by relying on the module system to only have one copy 1804 * of the module loaded, and then by giving the rcu_torture_stats 1805 * kthread full control (or the init/cleanup functions when rcu_torture_stats 1806 * thread is not running). 1807 */ 1808 static void 1809 rcu_torture_stats_print(void) 1810 { 1811 int cpu; 1812 int i; 1813 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; 1814 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; 1815 struct rcu_torture *rtcp; 1816 static unsigned long rtcv_snap = ULONG_MAX; 1817 static bool splatted; 1818 struct task_struct *wtp; 1819 1820 for_each_possible_cpu(cpu) { 1821 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 1822 pipesummary[i] += READ_ONCE(per_cpu(rcu_torture_count, cpu)[i]); 1823 batchsummary[i] += READ_ONCE(per_cpu(rcu_torture_batch, cpu)[i]); 1824 } 1825 } 1826 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) { 1827 if (pipesummary[i] != 0) 1828 break; 1829 } 1830 1831 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1832 rtcp = rcu_access_pointer(rcu_torture_current); 1833 pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ", 1834 rtcp, 1835 rtcp && !rcu_stall_is_suppressed_at_boot() ? "ver" : "VER", 1836 rcu_torture_current_version, 1837 list_empty(&rcu_torture_freelist), 1838 atomic_read(&n_rcu_torture_alloc), 1839 atomic_read(&n_rcu_torture_alloc_fail), 1840 atomic_read(&n_rcu_torture_free)); 1841 pr_cont("rtmbe: %d rtmbkf: %d/%d rtbe: %ld rtbke: %ld rtbre: %ld ", 1842 atomic_read(&n_rcu_torture_mberror), 1843 atomic_read(&n_rcu_torture_mbchk_fail), atomic_read(&n_rcu_torture_mbchk_tries), 1844 n_rcu_torture_barrier_error, 1845 n_rcu_torture_boost_ktrerror, 1846 n_rcu_torture_boost_rterror); 1847 pr_cont("rtbf: %ld rtb: %ld nt: %ld ", 1848 n_rcu_torture_boost_failure, 1849 n_rcu_torture_boosts, 1850 atomic_long_read(&n_rcu_torture_timers)); 1851 torture_onoff_stats(); 1852 pr_cont("barrier: %ld/%ld:%ld ", 1853 data_race(n_barrier_successes), 1854 data_race(n_barrier_attempts), 1855 data_race(n_rcu_torture_barrier_error)); 1856 pr_cont("read-exits: %ld ", data_race(n_read_exits)); // Statistic. 1857 pr_cont("nocb-toggles: %ld:%ld\n", 1858 atomic_long_read(&n_nocb_offload), atomic_long_read(&n_nocb_deoffload)); 1859 1860 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1861 if (atomic_read(&n_rcu_torture_mberror) || 1862 atomic_read(&n_rcu_torture_mbchk_fail) || 1863 n_rcu_torture_barrier_error || n_rcu_torture_boost_ktrerror || 1864 n_rcu_torture_boost_rterror || n_rcu_torture_boost_failure || 1865 i > 1) { 1866 pr_cont("%s", "!!! "); 1867 atomic_inc(&n_rcu_torture_error); 1868 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mberror)); 1869 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mbchk_fail)); 1870 WARN_ON_ONCE(n_rcu_torture_barrier_error); // rcu_barrier() 1871 WARN_ON_ONCE(n_rcu_torture_boost_ktrerror); // no boost kthread 1872 WARN_ON_ONCE(n_rcu_torture_boost_rterror); // can't set RT prio 1873 WARN_ON_ONCE(n_rcu_torture_boost_failure); // boost failed (TIMER_SOFTIRQ RT prio?) 1874 WARN_ON_ONCE(i > 1); // Too-short grace period 1875 } 1876 pr_cont("Reader Pipe: "); 1877 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 1878 pr_cont(" %ld", pipesummary[i]); 1879 pr_cont("\n"); 1880 1881 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1882 pr_cont("Reader Batch: "); 1883 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 1884 pr_cont(" %ld", batchsummary[i]); 1885 pr_cont("\n"); 1886 1887 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1888 pr_cont("Free-Block Circulation: "); 1889 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 1890 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i])); 1891 } 1892 pr_cont("\n"); 1893 1894 if (cur_ops->stats) 1895 cur_ops->stats(); 1896 if (rtcv_snap == rcu_torture_current_version && 1897 rcu_access_pointer(rcu_torture_current) && 1898 !rcu_stall_is_suppressed()) { 1899 int __maybe_unused flags = 0; 1900 unsigned long __maybe_unused gp_seq = 0; 1901 1902 rcutorture_get_gp_data(cur_ops->ttype, 1903 &flags, &gp_seq); 1904 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, 1905 &flags, &gp_seq); 1906 wtp = READ_ONCE(writer_task); 1907 pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#x cpu %d\n", 1908 rcu_torture_writer_state_getname(), 1909 rcu_torture_writer_state, gp_seq, flags, 1910 wtp == NULL ? ~0U : wtp->__state, 1911 wtp == NULL ? -1 : (int)task_cpu(wtp)); 1912 if (!splatted && wtp) { 1913 sched_show_task(wtp); 1914 splatted = true; 1915 } 1916 if (cur_ops->gp_kthread_dbg) 1917 cur_ops->gp_kthread_dbg(); 1918 rcu_ftrace_dump(DUMP_ALL); 1919 } 1920 rtcv_snap = rcu_torture_current_version; 1921 } 1922 1923 /* 1924 * Periodically prints torture statistics, if periodic statistics printing 1925 * was specified via the stat_interval module parameter. 1926 */ 1927 static int 1928 rcu_torture_stats(void *arg) 1929 { 1930 VERBOSE_TOROUT_STRING("rcu_torture_stats task started"); 1931 do { 1932 schedule_timeout_interruptible(stat_interval * HZ); 1933 rcu_torture_stats_print(); 1934 torture_shutdown_absorb("rcu_torture_stats"); 1935 } while (!torture_must_stop()); 1936 torture_kthread_stopping("rcu_torture_stats"); 1937 return 0; 1938 } 1939 1940 /* Test mem_dump_obj() and friends. */ 1941 static void rcu_torture_mem_dump_obj(void) 1942 { 1943 struct rcu_head *rhp; 1944 struct kmem_cache *kcp; 1945 static int z; 1946 1947 kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL); 1948 rhp = kmem_cache_alloc(kcp, GFP_KERNEL); 1949 pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z); 1950 pr_alert("mem_dump_obj(ZERO_SIZE_PTR):"); 1951 mem_dump_obj(ZERO_SIZE_PTR); 1952 pr_alert("mem_dump_obj(NULL):"); 1953 mem_dump_obj(NULL); 1954 pr_alert("mem_dump_obj(%px):", &rhp); 1955 mem_dump_obj(&rhp); 1956 pr_alert("mem_dump_obj(%px):", rhp); 1957 mem_dump_obj(rhp); 1958 pr_alert("mem_dump_obj(%px):", &rhp->func); 1959 mem_dump_obj(&rhp->func); 1960 pr_alert("mem_dump_obj(%px):", &z); 1961 mem_dump_obj(&z); 1962 kmem_cache_free(kcp, rhp); 1963 kmem_cache_destroy(kcp); 1964 rhp = kmalloc(sizeof(*rhp), GFP_KERNEL); 1965 pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp); 1966 pr_alert("mem_dump_obj(kmalloc %px):", rhp); 1967 mem_dump_obj(rhp); 1968 pr_alert("mem_dump_obj(kmalloc %px):", &rhp->func); 1969 mem_dump_obj(&rhp->func); 1970 kfree(rhp); 1971 rhp = vmalloc(4096); 1972 pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp); 1973 pr_alert("mem_dump_obj(vmalloc %px):", rhp); 1974 mem_dump_obj(rhp); 1975 pr_alert("mem_dump_obj(vmalloc %px):", &rhp->func); 1976 mem_dump_obj(&rhp->func); 1977 vfree(rhp); 1978 } 1979 1980 static void 1981 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag) 1982 { 1983 pr_alert("%s" TORTURE_FLAG 1984 "--- %s: nreaders=%d nfakewriters=%d " 1985 "stat_interval=%d verbose=%d test_no_idle_hz=%d " 1986 "shuffle_interval=%d stutter=%d irqreader=%d " 1987 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d " 1988 "test_boost=%d/%d test_boost_interval=%d " 1989 "test_boost_duration=%d shutdown_secs=%d " 1990 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d " 1991 "stall_cpu_block=%d " 1992 "n_barrier_cbs=%d " 1993 "onoff_interval=%d onoff_holdoff=%d " 1994 "read_exit_delay=%d read_exit_burst=%d " 1995 "nocbs_nthreads=%d nocbs_toggle=%d\n", 1996 torture_type, tag, nrealreaders, nfakewriters, 1997 stat_interval, verbose, test_no_idle_hz, shuffle_interval, 1998 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter, 1999 test_boost, cur_ops->can_boost, 2000 test_boost_interval, test_boost_duration, shutdown_secs, 2001 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff, 2002 stall_cpu_block, 2003 n_barrier_cbs, 2004 onoff_interval, onoff_holdoff, 2005 read_exit_delay, read_exit_burst, 2006 nocbs_nthreads, nocbs_toggle); 2007 } 2008 2009 static int rcutorture_booster_cleanup(unsigned int cpu) 2010 { 2011 struct task_struct *t; 2012 2013 if (boost_tasks[cpu] == NULL) 2014 return 0; 2015 mutex_lock(&boost_mutex); 2016 t = boost_tasks[cpu]; 2017 boost_tasks[cpu] = NULL; 2018 rcu_torture_enable_rt_throttle(); 2019 mutex_unlock(&boost_mutex); 2020 2021 /* This must be outside of the mutex, otherwise deadlock! */ 2022 torture_stop_kthread(rcu_torture_boost, t); 2023 return 0; 2024 } 2025 2026 static int rcutorture_booster_init(unsigned int cpu) 2027 { 2028 int retval; 2029 2030 if (boost_tasks[cpu] != NULL) 2031 return 0; /* Already created, nothing more to do. */ 2032 2033 /* Don't allow time recalculation while creating a new task. */ 2034 mutex_lock(&boost_mutex); 2035 rcu_torture_disable_rt_throttle(); 2036 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task"); 2037 boost_tasks[cpu] = kthread_run_on_cpu(rcu_torture_boost, NULL, 2038 cpu, "rcu_torture_boost_%u"); 2039 if (IS_ERR(boost_tasks[cpu])) { 2040 retval = PTR_ERR(boost_tasks[cpu]); 2041 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed"); 2042 n_rcu_torture_boost_ktrerror++; 2043 boost_tasks[cpu] = NULL; 2044 mutex_unlock(&boost_mutex); 2045 return retval; 2046 } 2047 mutex_unlock(&boost_mutex); 2048 return 0; 2049 } 2050 2051 /* 2052 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then 2053 * induces a CPU stall for the time specified by stall_cpu. 2054 */ 2055 static int rcu_torture_stall(void *args) 2056 { 2057 int idx; 2058 unsigned long stop_at; 2059 2060 VERBOSE_TOROUT_STRING("rcu_torture_stall task started"); 2061 if (stall_cpu_holdoff > 0) { 2062 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff"); 2063 schedule_timeout_interruptible(stall_cpu_holdoff * HZ); 2064 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff"); 2065 } 2066 if (!kthread_should_stop() && stall_gp_kthread > 0) { 2067 VERBOSE_TOROUT_STRING("rcu_torture_stall begin GP stall"); 2068 rcu_gp_set_torture_wait(stall_gp_kthread * HZ); 2069 for (idx = 0; idx < stall_gp_kthread + 2; idx++) { 2070 if (kthread_should_stop()) 2071 break; 2072 schedule_timeout_uninterruptible(HZ); 2073 } 2074 } 2075 if (!kthread_should_stop() && stall_cpu > 0) { 2076 VERBOSE_TOROUT_STRING("rcu_torture_stall begin CPU stall"); 2077 stop_at = ktime_get_seconds() + stall_cpu; 2078 /* RCU CPU stall is expected behavior in following code. */ 2079 idx = cur_ops->readlock(); 2080 if (stall_cpu_irqsoff) 2081 local_irq_disable(); 2082 else if (!stall_cpu_block) 2083 preempt_disable(); 2084 pr_alert("%s start on CPU %d.\n", 2085 __func__, raw_smp_processor_id()); 2086 while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(), 2087 stop_at)) 2088 if (stall_cpu_block) { 2089 #ifdef CONFIG_PREEMPTION 2090 preempt_schedule(); 2091 #else 2092 schedule_timeout_uninterruptible(HZ); 2093 #endif 2094 } else if (stall_no_softlockup) { 2095 touch_softlockup_watchdog(); 2096 } 2097 if (stall_cpu_irqsoff) 2098 local_irq_enable(); 2099 else if (!stall_cpu_block) 2100 preempt_enable(); 2101 cur_ops->readunlock(idx); 2102 } 2103 pr_alert("%s end.\n", __func__); 2104 torture_shutdown_absorb("rcu_torture_stall"); 2105 while (!kthread_should_stop()) 2106 schedule_timeout_interruptible(10 * HZ); 2107 return 0; 2108 } 2109 2110 /* Spawn CPU-stall kthread, if stall_cpu specified. */ 2111 static int __init rcu_torture_stall_init(void) 2112 { 2113 if (stall_cpu <= 0 && stall_gp_kthread <= 0) 2114 return 0; 2115 return torture_create_kthread(rcu_torture_stall, NULL, stall_task); 2116 } 2117 2118 /* State structure for forward-progress self-propagating RCU callback. */ 2119 struct fwd_cb_state { 2120 struct rcu_head rh; 2121 int stop; 2122 }; 2123 2124 /* 2125 * Forward-progress self-propagating RCU callback function. Because 2126 * callbacks run from softirq, this function is an implicit RCU read-side 2127 * critical section. 2128 */ 2129 static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp) 2130 { 2131 struct fwd_cb_state *fcsp = container_of(rhp, struct fwd_cb_state, rh); 2132 2133 if (READ_ONCE(fcsp->stop)) { 2134 WRITE_ONCE(fcsp->stop, 2); 2135 return; 2136 } 2137 cur_ops->call(&fcsp->rh, rcu_torture_fwd_prog_cb); 2138 } 2139 2140 /* State for continuous-flood RCU callbacks. */ 2141 struct rcu_fwd_cb { 2142 struct rcu_head rh; 2143 struct rcu_fwd_cb *rfc_next; 2144 struct rcu_fwd *rfc_rfp; 2145 int rfc_gps; 2146 }; 2147 2148 #define MAX_FWD_CB_JIFFIES (8 * HZ) /* Maximum CB test duration. */ 2149 #define MIN_FWD_CB_LAUNDERS 3 /* This many CB invocations to count. */ 2150 #define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */ 2151 #define FWD_CBS_HIST_DIV 10 /* Histogram buckets/second. */ 2152 #define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV)) 2153 2154 struct rcu_launder_hist { 2155 long n_launders; 2156 unsigned long launder_gp_seq; 2157 }; 2158 2159 struct rcu_fwd { 2160 spinlock_t rcu_fwd_lock; 2161 struct rcu_fwd_cb *rcu_fwd_cb_head; 2162 struct rcu_fwd_cb **rcu_fwd_cb_tail; 2163 long n_launders_cb; 2164 unsigned long rcu_fwd_startat; 2165 struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST]; 2166 unsigned long rcu_launder_gp_seq_start; 2167 int rcu_fwd_id; 2168 }; 2169 2170 static DEFINE_MUTEX(rcu_fwd_mutex); 2171 static struct rcu_fwd *rcu_fwds; 2172 static unsigned long rcu_fwd_seq; 2173 static atomic_long_t rcu_fwd_max_cbs; 2174 static bool rcu_fwd_emergency_stop; 2175 2176 static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp) 2177 { 2178 unsigned long gps; 2179 unsigned long gps_old; 2180 int i; 2181 int j; 2182 2183 for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--) 2184 if (rfp->n_launders_hist[i].n_launders > 0) 2185 break; 2186 pr_alert("%s: Callback-invocation histogram %d (duration %lu jiffies):", 2187 __func__, rfp->rcu_fwd_id, jiffies - rfp->rcu_fwd_startat); 2188 gps_old = rfp->rcu_launder_gp_seq_start; 2189 for (j = 0; j <= i; j++) { 2190 gps = rfp->n_launders_hist[j].launder_gp_seq; 2191 pr_cont(" %ds/%d: %ld:%ld", 2192 j + 1, FWD_CBS_HIST_DIV, 2193 rfp->n_launders_hist[j].n_launders, 2194 rcutorture_seq_diff(gps, gps_old)); 2195 gps_old = gps; 2196 } 2197 pr_cont("\n"); 2198 } 2199 2200 /* Callback function for continuous-flood RCU callbacks. */ 2201 static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp) 2202 { 2203 unsigned long flags; 2204 int i; 2205 struct rcu_fwd_cb *rfcp = container_of(rhp, struct rcu_fwd_cb, rh); 2206 struct rcu_fwd_cb **rfcpp; 2207 struct rcu_fwd *rfp = rfcp->rfc_rfp; 2208 2209 rfcp->rfc_next = NULL; 2210 rfcp->rfc_gps++; 2211 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags); 2212 rfcpp = rfp->rcu_fwd_cb_tail; 2213 rfp->rcu_fwd_cb_tail = &rfcp->rfc_next; 2214 WRITE_ONCE(*rfcpp, rfcp); 2215 WRITE_ONCE(rfp->n_launders_cb, rfp->n_launders_cb + 1); 2216 i = ((jiffies - rfp->rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV)); 2217 if (i >= ARRAY_SIZE(rfp->n_launders_hist)) 2218 i = ARRAY_SIZE(rfp->n_launders_hist) - 1; 2219 rfp->n_launders_hist[i].n_launders++; 2220 rfp->n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq(); 2221 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 2222 } 2223 2224 // Give the scheduler a chance, even on nohz_full CPUs. 2225 static void rcu_torture_fwd_prog_cond_resched(unsigned long iter) 2226 { 2227 if (IS_ENABLED(CONFIG_PREEMPTION) && IS_ENABLED(CONFIG_NO_HZ_FULL)) { 2228 // Real call_rcu() floods hit userspace, so emulate that. 2229 if (need_resched() || (iter & 0xfff)) 2230 schedule(); 2231 return; 2232 } 2233 // No userspace emulation: CB invocation throttles call_rcu() 2234 cond_resched(); 2235 } 2236 2237 /* 2238 * Free all callbacks on the rcu_fwd_cb_head list, either because the 2239 * test is over or because we hit an OOM event. 2240 */ 2241 static unsigned long rcu_torture_fwd_prog_cbfree(struct rcu_fwd *rfp) 2242 { 2243 unsigned long flags; 2244 unsigned long freed = 0; 2245 struct rcu_fwd_cb *rfcp; 2246 2247 for (;;) { 2248 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags); 2249 rfcp = rfp->rcu_fwd_cb_head; 2250 if (!rfcp) { 2251 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 2252 break; 2253 } 2254 rfp->rcu_fwd_cb_head = rfcp->rfc_next; 2255 if (!rfp->rcu_fwd_cb_head) 2256 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head; 2257 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 2258 kfree(rfcp); 2259 freed++; 2260 rcu_torture_fwd_prog_cond_resched(freed); 2261 if (tick_nohz_full_enabled()) { 2262 local_irq_save(flags); 2263 rcu_momentary_dyntick_idle(); 2264 local_irq_restore(flags); 2265 } 2266 } 2267 return freed; 2268 } 2269 2270 /* Carry out need_resched()/cond_resched() forward-progress testing. */ 2271 static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp, 2272 int *tested, int *tested_tries) 2273 { 2274 unsigned long cver; 2275 unsigned long dur; 2276 struct fwd_cb_state fcs; 2277 unsigned long gps; 2278 int idx; 2279 int sd; 2280 int sd4; 2281 bool selfpropcb = false; 2282 unsigned long stopat; 2283 static DEFINE_TORTURE_RANDOM(trs); 2284 2285 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id); 2286 if (!cur_ops->sync) 2287 return; // Cannot do need_resched() forward progress testing without ->sync. 2288 if (cur_ops->call && cur_ops->cb_barrier) { 2289 init_rcu_head_on_stack(&fcs.rh); 2290 selfpropcb = true; 2291 } 2292 2293 /* Tight loop containing cond_resched(). */ 2294 atomic_inc(&rcu_fwd_cb_nodelay); 2295 cur_ops->sync(); /* Later readers see above write. */ 2296 if (selfpropcb) { 2297 WRITE_ONCE(fcs.stop, 0); 2298 cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb); 2299 } 2300 cver = READ_ONCE(rcu_torture_current_version); 2301 gps = cur_ops->get_gp_seq(); 2302 sd = cur_ops->stall_dur() + 1; 2303 sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div; 2304 dur = sd4 + torture_random(&trs) % (sd - sd4); 2305 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies); 2306 stopat = rfp->rcu_fwd_startat + dur; 2307 while (time_before(jiffies, stopat) && 2308 !shutdown_time_arrived() && 2309 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 2310 idx = cur_ops->readlock(); 2311 udelay(10); 2312 cur_ops->readunlock(idx); 2313 if (!fwd_progress_need_resched || need_resched()) 2314 cond_resched(); 2315 } 2316 (*tested_tries)++; 2317 if (!time_before(jiffies, stopat) && 2318 !shutdown_time_arrived() && 2319 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 2320 (*tested)++; 2321 cver = READ_ONCE(rcu_torture_current_version) - cver; 2322 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps); 2323 WARN_ON(!cver && gps < 2); 2324 pr_alert("%s: %d Duration %ld cver %ld gps %ld\n", __func__, 2325 rfp->rcu_fwd_id, dur, cver, gps); 2326 } 2327 if (selfpropcb) { 2328 WRITE_ONCE(fcs.stop, 1); 2329 cur_ops->sync(); /* Wait for running CB to complete. */ 2330 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id); 2331 cur_ops->cb_barrier(); /* Wait for queued callbacks. */ 2332 } 2333 2334 if (selfpropcb) { 2335 WARN_ON(READ_ONCE(fcs.stop) != 2); 2336 destroy_rcu_head_on_stack(&fcs.rh); 2337 } 2338 schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */ 2339 atomic_dec(&rcu_fwd_cb_nodelay); 2340 } 2341 2342 /* Carry out call_rcu() forward-progress testing. */ 2343 static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp) 2344 { 2345 unsigned long cver; 2346 unsigned long flags; 2347 unsigned long gps; 2348 int i; 2349 long n_launders; 2350 long n_launders_cb_snap; 2351 long n_launders_sa; 2352 long n_max_cbs; 2353 long n_max_gps; 2354 struct rcu_fwd_cb *rfcp; 2355 struct rcu_fwd_cb *rfcpn; 2356 unsigned long stopat; 2357 unsigned long stoppedat; 2358 2359 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id); 2360 if (READ_ONCE(rcu_fwd_emergency_stop)) 2361 return; /* Get out of the way quickly, no GP wait! */ 2362 if (!cur_ops->call) 2363 return; /* Can't do call_rcu() fwd prog without ->call. */ 2364 2365 /* Loop continuously posting RCU callbacks. */ 2366 atomic_inc(&rcu_fwd_cb_nodelay); 2367 cur_ops->sync(); /* Later readers see above write. */ 2368 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies); 2369 stopat = rfp->rcu_fwd_startat + MAX_FWD_CB_JIFFIES; 2370 n_launders = 0; 2371 rfp->n_launders_cb = 0; // Hoist initialization for multi-kthread 2372 n_launders_sa = 0; 2373 n_max_cbs = 0; 2374 n_max_gps = 0; 2375 for (i = 0; i < ARRAY_SIZE(rfp->n_launders_hist); i++) 2376 rfp->n_launders_hist[i].n_launders = 0; 2377 cver = READ_ONCE(rcu_torture_current_version); 2378 gps = cur_ops->get_gp_seq(); 2379 rfp->rcu_launder_gp_seq_start = gps; 2380 tick_dep_set_task(current, TICK_DEP_BIT_RCU); 2381 while (time_before(jiffies, stopat) && 2382 !shutdown_time_arrived() && 2383 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 2384 rfcp = READ_ONCE(rfp->rcu_fwd_cb_head); 2385 rfcpn = NULL; 2386 if (rfcp) 2387 rfcpn = READ_ONCE(rfcp->rfc_next); 2388 if (rfcpn) { 2389 if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS && 2390 ++n_max_gps >= MIN_FWD_CBS_LAUNDERED) 2391 break; 2392 rfp->rcu_fwd_cb_head = rfcpn; 2393 n_launders++; 2394 n_launders_sa++; 2395 } else if (!cur_ops->cbflood_max || cur_ops->cbflood_max > n_max_cbs) { 2396 rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL); 2397 if (WARN_ON_ONCE(!rfcp)) { 2398 schedule_timeout_interruptible(1); 2399 continue; 2400 } 2401 n_max_cbs++; 2402 n_launders_sa = 0; 2403 rfcp->rfc_gps = 0; 2404 rfcp->rfc_rfp = rfp; 2405 } else { 2406 rfcp = NULL; 2407 } 2408 if (rfcp) 2409 cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr); 2410 rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs); 2411 if (tick_nohz_full_enabled()) { 2412 local_irq_save(flags); 2413 rcu_momentary_dyntick_idle(); 2414 local_irq_restore(flags); 2415 } 2416 } 2417 stoppedat = jiffies; 2418 n_launders_cb_snap = READ_ONCE(rfp->n_launders_cb); 2419 cver = READ_ONCE(rcu_torture_current_version) - cver; 2420 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps); 2421 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id); 2422 cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */ 2423 (void)rcu_torture_fwd_prog_cbfree(rfp); 2424 2425 if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) && 2426 !shutdown_time_arrived()) { 2427 WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED); 2428 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", 2429 __func__, 2430 stoppedat - rfp->rcu_fwd_startat, jiffies - stoppedat, 2431 n_launders + n_max_cbs - n_launders_cb_snap, 2432 n_launders, n_launders_sa, 2433 n_max_gps, n_max_cbs, cver, gps); 2434 atomic_long_add(n_max_cbs, &rcu_fwd_max_cbs); 2435 mutex_lock(&rcu_fwd_mutex); // Serialize histograms. 2436 rcu_torture_fwd_cb_hist(rfp); 2437 mutex_unlock(&rcu_fwd_mutex); 2438 } 2439 schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */ 2440 tick_dep_clear_task(current, TICK_DEP_BIT_RCU); 2441 atomic_dec(&rcu_fwd_cb_nodelay); 2442 } 2443 2444 2445 /* 2446 * OOM notifier, but this only prints diagnostic information for the 2447 * current forward-progress test. 2448 */ 2449 static int rcutorture_oom_notify(struct notifier_block *self, 2450 unsigned long notused, void *nfreed) 2451 { 2452 int i; 2453 long ncbs; 2454 struct rcu_fwd *rfp; 2455 2456 mutex_lock(&rcu_fwd_mutex); 2457 rfp = rcu_fwds; 2458 if (!rfp) { 2459 mutex_unlock(&rcu_fwd_mutex); 2460 return NOTIFY_OK; 2461 } 2462 WARN(1, "%s invoked upon OOM during forward-progress testing.\n", 2463 __func__); 2464 for (i = 0; i < fwd_progress; i++) { 2465 rcu_torture_fwd_cb_hist(&rfp[i]); 2466 rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp[i].rcu_fwd_startat)) / 2); 2467 } 2468 WRITE_ONCE(rcu_fwd_emergency_stop, true); 2469 smp_mb(); /* Emergency stop before free and wait to avoid hangs. */ 2470 ncbs = 0; 2471 for (i = 0; i < fwd_progress; i++) 2472 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]); 2473 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs); 2474 rcu_barrier(); 2475 ncbs = 0; 2476 for (i = 0; i < fwd_progress; i++) 2477 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]); 2478 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs); 2479 rcu_barrier(); 2480 ncbs = 0; 2481 for (i = 0; i < fwd_progress; i++) 2482 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]); 2483 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs); 2484 smp_mb(); /* Frees before return to avoid redoing OOM. */ 2485 (*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */ 2486 pr_info("%s returning after OOM processing.\n", __func__); 2487 mutex_unlock(&rcu_fwd_mutex); 2488 return NOTIFY_OK; 2489 } 2490 2491 static struct notifier_block rcutorture_oom_nb = { 2492 .notifier_call = rcutorture_oom_notify 2493 }; 2494 2495 /* Carry out grace-period forward-progress testing. */ 2496 static int rcu_torture_fwd_prog(void *args) 2497 { 2498 bool firsttime = true; 2499 long max_cbs; 2500 int oldnice = task_nice(current); 2501 unsigned long oldseq = READ_ONCE(rcu_fwd_seq); 2502 struct rcu_fwd *rfp = args; 2503 int tested = 0; 2504 int tested_tries = 0; 2505 2506 VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started"); 2507 rcu_bind_current_to_nocb(); 2508 if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST)) 2509 set_user_nice(current, MAX_NICE); 2510 do { 2511 if (!rfp->rcu_fwd_id) { 2512 schedule_timeout_interruptible(fwd_progress_holdoff * HZ); 2513 WRITE_ONCE(rcu_fwd_emergency_stop, false); 2514 if (!firsttime) { 2515 max_cbs = atomic_long_xchg(&rcu_fwd_max_cbs, 0); 2516 pr_alert("%s n_max_cbs: %ld\n", __func__, max_cbs); 2517 } 2518 firsttime = false; 2519 WRITE_ONCE(rcu_fwd_seq, rcu_fwd_seq + 1); 2520 } else { 2521 while (READ_ONCE(rcu_fwd_seq) == oldseq && !torture_must_stop()) 2522 schedule_timeout_interruptible(1); 2523 oldseq = READ_ONCE(rcu_fwd_seq); 2524 } 2525 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id); 2526 if (rcu_inkernel_boot_has_ended() && torture_num_online_cpus() > rfp->rcu_fwd_id) 2527 rcu_torture_fwd_prog_cr(rfp); 2528 if ((cur_ops->stall_dur && cur_ops->stall_dur() > 0) && 2529 (!IS_ENABLED(CONFIG_TINY_RCU) || 2530 (rcu_inkernel_boot_has_ended() && 2531 torture_num_online_cpus() > rfp->rcu_fwd_id))) 2532 rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries); 2533 2534 /* Avoid slow periods, better to test when busy. */ 2535 if (stutter_wait("rcu_torture_fwd_prog")) 2536 sched_set_normal(current, oldnice); 2537 } while (!torture_must_stop()); 2538 /* Short runs might not contain a valid forward-progress attempt. */ 2539 if (!rfp->rcu_fwd_id) { 2540 WARN_ON(!tested && tested_tries >= 5); 2541 pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries); 2542 } 2543 torture_kthread_stopping("rcu_torture_fwd_prog"); 2544 return 0; 2545 } 2546 2547 /* If forward-progress checking is requested and feasible, spawn the thread. */ 2548 static int __init rcu_torture_fwd_prog_init(void) 2549 { 2550 int i; 2551 int ret = 0; 2552 struct rcu_fwd *rfp; 2553 2554 if (!fwd_progress) 2555 return 0; /* Not requested, so don't do it. */ 2556 if (fwd_progress >= nr_cpu_ids) { 2557 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Limiting fwd_progress to # CPUs.\n"); 2558 fwd_progress = nr_cpu_ids; 2559 } else if (fwd_progress < 0) { 2560 fwd_progress = nr_cpu_ids; 2561 } 2562 if ((!cur_ops->sync && !cur_ops->call) || 2563 (!cur_ops->cbflood_max && (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0)) || 2564 cur_ops == &rcu_busted_ops) { 2565 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test"); 2566 fwd_progress = 0; 2567 return 0; 2568 } 2569 if (stall_cpu > 0) { 2570 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing"); 2571 fwd_progress = 0; 2572 if (IS_MODULE(CONFIG_RCU_TORTURE_TEST)) 2573 return -EINVAL; /* In module, can fail back to user. */ 2574 WARN_ON(1); /* Make sure rcutorture notices conflict. */ 2575 return 0; 2576 } 2577 if (fwd_progress_holdoff <= 0) 2578 fwd_progress_holdoff = 1; 2579 if (fwd_progress_div <= 0) 2580 fwd_progress_div = 4; 2581 rfp = kcalloc(fwd_progress, sizeof(*rfp), GFP_KERNEL); 2582 fwd_prog_tasks = kcalloc(fwd_progress, sizeof(*fwd_prog_tasks), GFP_KERNEL); 2583 if (!rfp || !fwd_prog_tasks) { 2584 kfree(rfp); 2585 kfree(fwd_prog_tasks); 2586 fwd_prog_tasks = NULL; 2587 fwd_progress = 0; 2588 return -ENOMEM; 2589 } 2590 for (i = 0; i < fwd_progress; i++) { 2591 spin_lock_init(&rfp[i].rcu_fwd_lock); 2592 rfp[i].rcu_fwd_cb_tail = &rfp[i].rcu_fwd_cb_head; 2593 rfp[i].rcu_fwd_id = i; 2594 } 2595 mutex_lock(&rcu_fwd_mutex); 2596 rcu_fwds = rfp; 2597 mutex_unlock(&rcu_fwd_mutex); 2598 register_oom_notifier(&rcutorture_oom_nb); 2599 for (i = 0; i < fwd_progress; i++) { 2600 ret = torture_create_kthread(rcu_torture_fwd_prog, &rcu_fwds[i], fwd_prog_tasks[i]); 2601 if (ret) { 2602 fwd_progress = i; 2603 return ret; 2604 } 2605 } 2606 return 0; 2607 } 2608 2609 static void rcu_torture_fwd_prog_cleanup(void) 2610 { 2611 int i; 2612 struct rcu_fwd *rfp; 2613 2614 if (!rcu_fwds || !fwd_prog_tasks) 2615 return; 2616 for (i = 0; i < fwd_progress; i++) 2617 torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_tasks[i]); 2618 unregister_oom_notifier(&rcutorture_oom_nb); 2619 mutex_lock(&rcu_fwd_mutex); 2620 rfp = rcu_fwds; 2621 rcu_fwds = NULL; 2622 mutex_unlock(&rcu_fwd_mutex); 2623 kfree(rfp); 2624 kfree(fwd_prog_tasks); 2625 fwd_prog_tasks = NULL; 2626 } 2627 2628 /* Callback function for RCU barrier testing. */ 2629 static void rcu_torture_barrier_cbf(struct rcu_head *rcu) 2630 { 2631 atomic_inc(&barrier_cbs_invoked); 2632 } 2633 2634 /* IPI handler to get callback posted on desired CPU, if online. */ 2635 static void rcu_torture_barrier1cb(void *rcu_void) 2636 { 2637 struct rcu_head *rhp = rcu_void; 2638 2639 cur_ops->call(rhp, rcu_torture_barrier_cbf); 2640 } 2641 2642 /* kthread function to register callbacks used to test RCU barriers. */ 2643 static int rcu_torture_barrier_cbs(void *arg) 2644 { 2645 long myid = (long)arg; 2646 bool lastphase = false; 2647 bool newphase; 2648 struct rcu_head rcu; 2649 2650 init_rcu_head_on_stack(&rcu); 2651 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started"); 2652 set_user_nice(current, MAX_NICE); 2653 do { 2654 wait_event(barrier_cbs_wq[myid], 2655 (newphase = 2656 smp_load_acquire(&barrier_phase)) != lastphase || 2657 torture_must_stop()); 2658 lastphase = newphase; 2659 if (torture_must_stop()) 2660 break; 2661 /* 2662 * The above smp_load_acquire() ensures barrier_phase load 2663 * is ordered before the following ->call(). 2664 */ 2665 if (smp_call_function_single(myid, rcu_torture_barrier1cb, 2666 &rcu, 1)) { 2667 // IPI failed, so use direct call from current CPU. 2668 cur_ops->call(&rcu, rcu_torture_barrier_cbf); 2669 } 2670 if (atomic_dec_and_test(&barrier_cbs_count)) 2671 wake_up(&barrier_wq); 2672 } while (!torture_must_stop()); 2673 if (cur_ops->cb_barrier != NULL) 2674 cur_ops->cb_barrier(); 2675 destroy_rcu_head_on_stack(&rcu); 2676 torture_kthread_stopping("rcu_torture_barrier_cbs"); 2677 return 0; 2678 } 2679 2680 /* kthread function to drive and coordinate RCU barrier testing. */ 2681 static int rcu_torture_barrier(void *arg) 2682 { 2683 int i; 2684 2685 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting"); 2686 do { 2687 atomic_set(&barrier_cbs_invoked, 0); 2688 atomic_set(&barrier_cbs_count, n_barrier_cbs); 2689 /* Ensure barrier_phase ordered after prior assignments. */ 2690 smp_store_release(&barrier_phase, !barrier_phase); 2691 for (i = 0; i < n_barrier_cbs; i++) 2692 wake_up(&barrier_cbs_wq[i]); 2693 wait_event(barrier_wq, 2694 atomic_read(&barrier_cbs_count) == 0 || 2695 torture_must_stop()); 2696 if (torture_must_stop()) 2697 break; 2698 n_barrier_attempts++; 2699 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */ 2700 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) { 2701 n_rcu_torture_barrier_error++; 2702 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n", 2703 atomic_read(&barrier_cbs_invoked), 2704 n_barrier_cbs); 2705 WARN_ON(1); 2706 // Wait manually for the remaining callbacks 2707 i = 0; 2708 do { 2709 if (WARN_ON(i++ > HZ)) 2710 i = INT_MIN; 2711 schedule_timeout_interruptible(1); 2712 cur_ops->cb_barrier(); 2713 } while (atomic_read(&barrier_cbs_invoked) != 2714 n_barrier_cbs && 2715 !torture_must_stop()); 2716 smp_mb(); // Can't trust ordering if broken. 2717 if (!torture_must_stop()) 2718 pr_err("Recovered: barrier_cbs_invoked = %d\n", 2719 atomic_read(&barrier_cbs_invoked)); 2720 } else { 2721 n_barrier_successes++; 2722 } 2723 schedule_timeout_interruptible(HZ / 10); 2724 } while (!torture_must_stop()); 2725 torture_kthread_stopping("rcu_torture_barrier"); 2726 return 0; 2727 } 2728 2729 /* Initialize RCU barrier testing. */ 2730 static int rcu_torture_barrier_init(void) 2731 { 2732 int i; 2733 int ret; 2734 2735 if (n_barrier_cbs <= 0) 2736 return 0; 2737 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) { 2738 pr_alert("%s" TORTURE_FLAG 2739 " Call or barrier ops missing for %s,\n", 2740 torture_type, cur_ops->name); 2741 pr_alert("%s" TORTURE_FLAG 2742 " RCU barrier testing omitted from run.\n", 2743 torture_type); 2744 return 0; 2745 } 2746 atomic_set(&barrier_cbs_count, 0); 2747 atomic_set(&barrier_cbs_invoked, 0); 2748 barrier_cbs_tasks = 2749 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]), 2750 GFP_KERNEL); 2751 barrier_cbs_wq = 2752 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL); 2753 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq) 2754 return -ENOMEM; 2755 for (i = 0; i < n_barrier_cbs; i++) { 2756 init_waitqueue_head(&barrier_cbs_wq[i]); 2757 ret = torture_create_kthread(rcu_torture_barrier_cbs, 2758 (void *)(long)i, 2759 barrier_cbs_tasks[i]); 2760 if (ret) 2761 return ret; 2762 } 2763 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task); 2764 } 2765 2766 /* Clean up after RCU barrier testing. */ 2767 static void rcu_torture_barrier_cleanup(void) 2768 { 2769 int i; 2770 2771 torture_stop_kthread(rcu_torture_barrier, barrier_task); 2772 if (barrier_cbs_tasks != NULL) { 2773 for (i = 0; i < n_barrier_cbs; i++) 2774 torture_stop_kthread(rcu_torture_barrier_cbs, 2775 barrier_cbs_tasks[i]); 2776 kfree(barrier_cbs_tasks); 2777 barrier_cbs_tasks = NULL; 2778 } 2779 if (barrier_cbs_wq != NULL) { 2780 kfree(barrier_cbs_wq); 2781 barrier_cbs_wq = NULL; 2782 } 2783 } 2784 2785 static bool rcu_torture_can_boost(void) 2786 { 2787 static int boost_warn_once; 2788 int prio; 2789 2790 if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2) 2791 return false; 2792 if (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state) 2793 return false; 2794 2795 prio = rcu_get_gp_kthreads_prio(); 2796 if (!prio) 2797 return false; 2798 2799 if (prio < 2) { 2800 if (boost_warn_once == 1) 2801 return false; 2802 2803 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); 2804 boost_warn_once = 1; 2805 return false; 2806 } 2807 2808 return true; 2809 } 2810 2811 static bool read_exit_child_stop; 2812 static bool read_exit_child_stopped; 2813 static wait_queue_head_t read_exit_wq; 2814 2815 // Child kthread which just does an rcutorture reader and exits. 2816 static int rcu_torture_read_exit_child(void *trsp_in) 2817 { 2818 struct torture_random_state *trsp = trsp_in; 2819 2820 set_user_nice(current, MAX_NICE); 2821 // Minimize time between reading and exiting. 2822 while (!kthread_should_stop()) 2823 schedule_timeout_uninterruptible(1); 2824 (void)rcu_torture_one_read(trsp, -1); 2825 return 0; 2826 } 2827 2828 // Parent kthread which creates and destroys read-exit child kthreads. 2829 static int rcu_torture_read_exit(void *unused) 2830 { 2831 int count = 0; 2832 bool errexit = false; 2833 int i; 2834 struct task_struct *tsp; 2835 DEFINE_TORTURE_RANDOM(trs); 2836 2837 // Allocate and initialize. 2838 set_user_nice(current, MAX_NICE); 2839 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of test"); 2840 2841 // Each pass through this loop does one read-exit episode. 2842 do { 2843 if (++count > read_exit_burst) { 2844 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: End of episode"); 2845 rcu_barrier(); // Wait for task_struct free, avoid OOM. 2846 for (i = 0; i < read_exit_delay; i++) { 2847 schedule_timeout_uninterruptible(HZ); 2848 if (READ_ONCE(read_exit_child_stop)) 2849 break; 2850 } 2851 if (!READ_ONCE(read_exit_child_stop)) 2852 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of episode"); 2853 count = 0; 2854 } 2855 if (READ_ONCE(read_exit_child_stop)) 2856 break; 2857 // Spawn child. 2858 tsp = kthread_run(rcu_torture_read_exit_child, 2859 &trs, "%s", 2860 "rcu_torture_read_exit_child"); 2861 if (IS_ERR(tsp)) { 2862 TOROUT_ERRSTRING("out of memory"); 2863 errexit = true; 2864 tsp = NULL; 2865 break; 2866 } 2867 cond_resched(); 2868 kthread_stop(tsp); 2869 n_read_exits ++; 2870 stutter_wait("rcu_torture_read_exit"); 2871 } while (!errexit && !READ_ONCE(read_exit_child_stop)); 2872 2873 // Clean up and exit. 2874 smp_store_release(&read_exit_child_stopped, true); // After reaping. 2875 smp_mb(); // Store before wakeup. 2876 wake_up(&read_exit_wq); 2877 while (!torture_must_stop()) 2878 schedule_timeout_uninterruptible(1); 2879 torture_kthread_stopping("rcu_torture_read_exit"); 2880 return 0; 2881 } 2882 2883 static int rcu_torture_read_exit_init(void) 2884 { 2885 if (read_exit_burst <= 0) 2886 return 0; 2887 init_waitqueue_head(&read_exit_wq); 2888 read_exit_child_stop = false; 2889 read_exit_child_stopped = false; 2890 return torture_create_kthread(rcu_torture_read_exit, NULL, 2891 read_exit_task); 2892 } 2893 2894 static void rcu_torture_read_exit_cleanup(void) 2895 { 2896 if (!read_exit_task) 2897 return; 2898 WRITE_ONCE(read_exit_child_stop, true); 2899 smp_mb(); // Above write before wait. 2900 wait_event(read_exit_wq, smp_load_acquire(&read_exit_child_stopped)); 2901 torture_stop_kthread(rcutorture_read_exit, read_exit_task); 2902 } 2903 2904 static enum cpuhp_state rcutor_hp; 2905 2906 static void 2907 rcu_torture_cleanup(void) 2908 { 2909 int firsttime; 2910 int flags = 0; 2911 unsigned long gp_seq = 0; 2912 int i; 2913 2914 if (torture_cleanup_begin()) { 2915 if (cur_ops->cb_barrier != NULL) { 2916 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier); 2917 cur_ops->cb_barrier(); 2918 } 2919 return; 2920 } 2921 if (!cur_ops) { 2922 torture_cleanup_end(); 2923 return; 2924 } 2925 2926 if (cur_ops->gp_kthread_dbg) 2927 cur_ops->gp_kthread_dbg(); 2928 rcu_torture_read_exit_cleanup(); 2929 rcu_torture_barrier_cleanup(); 2930 rcu_torture_fwd_prog_cleanup(); 2931 torture_stop_kthread(rcu_torture_stall, stall_task); 2932 torture_stop_kthread(rcu_torture_writer, writer_task); 2933 2934 if (nocb_tasks) { 2935 for (i = 0; i < nrealnocbers; i++) 2936 torture_stop_kthread(rcu_nocb_toggle, nocb_tasks[i]); 2937 kfree(nocb_tasks); 2938 nocb_tasks = NULL; 2939 } 2940 2941 if (reader_tasks) { 2942 for (i = 0; i < nrealreaders; i++) 2943 torture_stop_kthread(rcu_torture_reader, 2944 reader_tasks[i]); 2945 kfree(reader_tasks); 2946 reader_tasks = NULL; 2947 } 2948 kfree(rcu_torture_reader_mbchk); 2949 rcu_torture_reader_mbchk = NULL; 2950 2951 if (fakewriter_tasks) { 2952 for (i = 0; i < nfakewriters; i++) 2953 torture_stop_kthread(rcu_torture_fakewriter, 2954 fakewriter_tasks[i]); 2955 kfree(fakewriter_tasks); 2956 fakewriter_tasks = NULL; 2957 } 2958 2959 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq); 2960 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq); 2961 pr_alert("%s: End-test grace-period state: g%ld f%#x total-gps=%ld\n", 2962 cur_ops->name, (long)gp_seq, flags, 2963 rcutorture_seq_diff(gp_seq, start_gp_seq)); 2964 torture_stop_kthread(rcu_torture_stats, stats_task); 2965 torture_stop_kthread(rcu_torture_fqs, fqs_task); 2966 if (rcu_torture_can_boost() && rcutor_hp >= 0) 2967 cpuhp_remove_state(rcutor_hp); 2968 2969 /* 2970 * Wait for all RCU callbacks to fire, then do torture-type-specific 2971 * cleanup operations. 2972 */ 2973 if (cur_ops->cb_barrier != NULL) { 2974 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier); 2975 cur_ops->cb_barrier(); 2976 } 2977 if (cur_ops->cleanup != NULL) 2978 cur_ops->cleanup(); 2979 2980 rcu_torture_mem_dump_obj(); 2981 2982 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */ 2983 2984 if (err_segs_recorded) { 2985 pr_alert("Failure/close-call rcutorture reader segments:\n"); 2986 if (rt_read_nsegs == 0) 2987 pr_alert("\t: No segments recorded!!!\n"); 2988 firsttime = 1; 2989 for (i = 0; i < rt_read_nsegs; i++) { 2990 pr_alert("\t%d: %#x ", i, err_segs[i].rt_readstate); 2991 if (err_segs[i].rt_delay_jiffies != 0) { 2992 pr_cont("%s%ldjiffies", firsttime ? "" : "+", 2993 err_segs[i].rt_delay_jiffies); 2994 firsttime = 0; 2995 } 2996 if (err_segs[i].rt_delay_ms != 0) { 2997 pr_cont("%s%ldms", firsttime ? "" : "+", 2998 err_segs[i].rt_delay_ms); 2999 firsttime = 0; 3000 } 3001 if (err_segs[i].rt_delay_us != 0) { 3002 pr_cont("%s%ldus", firsttime ? "" : "+", 3003 err_segs[i].rt_delay_us); 3004 firsttime = 0; 3005 } 3006 pr_cont("%s\n", 3007 err_segs[i].rt_preempted ? "preempted" : ""); 3008 3009 } 3010 } 3011 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error) 3012 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE"); 3013 else if (torture_onoff_failures()) 3014 rcu_torture_print_module_parms(cur_ops, 3015 "End of test: RCU_HOTPLUG"); 3016 else 3017 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS"); 3018 torture_cleanup_end(); 3019 } 3020 3021 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD 3022 static void rcu_torture_leak_cb(struct rcu_head *rhp) 3023 { 3024 } 3025 3026 static void rcu_torture_err_cb(struct rcu_head *rhp) 3027 { 3028 /* 3029 * This -might- happen due to race conditions, but is unlikely. 3030 * The scenario that leads to this happening is that the 3031 * first of the pair of duplicate callbacks is queued, 3032 * someone else starts a grace period that includes that 3033 * callback, then the second of the pair must wait for the 3034 * next grace period. Unlikely, but can happen. If it 3035 * does happen, the debug-objects subsystem won't have splatted. 3036 */ 3037 pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME); 3038 } 3039 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 3040 3041 /* 3042 * Verify that double-free causes debug-objects to complain, but only 3043 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test 3044 * cannot be carried out. 3045 */ 3046 static void rcu_test_debug_objects(void) 3047 { 3048 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD 3049 struct rcu_head rh1; 3050 struct rcu_head rh2; 3051 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_KERNEL); 3052 3053 init_rcu_head_on_stack(&rh1); 3054 init_rcu_head_on_stack(&rh2); 3055 pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME); 3056 3057 /* Try to queue the rh2 pair of callbacks for the same grace period. */ 3058 preempt_disable(); /* Prevent preemption from interrupting test. */ 3059 rcu_read_lock(); /* Make it impossible to finish a grace period. */ 3060 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */ 3061 local_irq_disable(); /* Make it harder to start a new grace period. */ 3062 call_rcu(&rh2, rcu_torture_leak_cb); 3063 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */ 3064 if (rhp) { 3065 call_rcu(rhp, rcu_torture_leak_cb); 3066 call_rcu(rhp, rcu_torture_err_cb); /* Another duplicate callback. */ 3067 } 3068 local_irq_enable(); 3069 rcu_read_unlock(); 3070 preempt_enable(); 3071 3072 /* Wait for them all to get done so we can safely return. */ 3073 rcu_barrier(); 3074 pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME); 3075 destroy_rcu_head_on_stack(&rh1); 3076 destroy_rcu_head_on_stack(&rh2); 3077 #else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 3078 pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME); 3079 #endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 3080 } 3081 3082 static void rcutorture_sync(void) 3083 { 3084 static unsigned long n; 3085 3086 if (cur_ops->sync && !(++n & 0xfff)) 3087 cur_ops->sync(); 3088 } 3089 3090 static int __init 3091 rcu_torture_init(void) 3092 { 3093 long i; 3094 int cpu; 3095 int firsterr = 0; 3096 int flags = 0; 3097 unsigned long gp_seq = 0; 3098 static struct rcu_torture_ops *torture_ops[] = { 3099 &rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops, 3100 &busted_srcud_ops, &tasks_ops, &tasks_rude_ops, 3101 &tasks_tracing_ops, &trivial_ops, 3102 }; 3103 3104 if (!torture_init_begin(torture_type, verbose)) 3105 return -EBUSY; 3106 3107 /* Process args and tell the world that the torturer is on the job. */ 3108 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) { 3109 cur_ops = torture_ops[i]; 3110 if (strcmp(torture_type, cur_ops->name) == 0) 3111 break; 3112 } 3113 if (i == ARRAY_SIZE(torture_ops)) { 3114 pr_alert("rcu-torture: invalid torture type: \"%s\"\n", 3115 torture_type); 3116 pr_alert("rcu-torture types:"); 3117 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) 3118 pr_cont(" %s", torture_ops[i]->name); 3119 pr_cont("\n"); 3120 firsterr = -EINVAL; 3121 cur_ops = NULL; 3122 goto unwind; 3123 } 3124 if (cur_ops->fqs == NULL && fqs_duration != 0) { 3125 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n"); 3126 fqs_duration = 0; 3127 } 3128 if (cur_ops->init) 3129 cur_ops->init(); 3130 3131 if (nreaders >= 0) { 3132 nrealreaders = nreaders; 3133 } else { 3134 nrealreaders = num_online_cpus() - 2 - nreaders; 3135 if (nrealreaders <= 0) 3136 nrealreaders = 1; 3137 } 3138 rcu_torture_print_module_parms(cur_ops, "Start of test"); 3139 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq); 3140 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq); 3141 start_gp_seq = gp_seq; 3142 pr_alert("%s: Start-test grace-period state: g%ld f%#x\n", 3143 cur_ops->name, (long)gp_seq, flags); 3144 3145 /* Set up the freelist. */ 3146 3147 INIT_LIST_HEAD(&rcu_torture_freelist); 3148 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) { 3149 rcu_tortures[i].rtort_mbtest = 0; 3150 list_add_tail(&rcu_tortures[i].rtort_free, 3151 &rcu_torture_freelist); 3152 } 3153 3154 /* Initialize the statistics so that each run gets its own numbers. */ 3155 3156 rcu_torture_current = NULL; 3157 rcu_torture_current_version = 0; 3158 atomic_set(&n_rcu_torture_alloc, 0); 3159 atomic_set(&n_rcu_torture_alloc_fail, 0); 3160 atomic_set(&n_rcu_torture_free, 0); 3161 atomic_set(&n_rcu_torture_mberror, 0); 3162 atomic_set(&n_rcu_torture_mbchk_fail, 0); 3163 atomic_set(&n_rcu_torture_mbchk_tries, 0); 3164 atomic_set(&n_rcu_torture_error, 0); 3165 n_rcu_torture_barrier_error = 0; 3166 n_rcu_torture_boost_ktrerror = 0; 3167 n_rcu_torture_boost_rterror = 0; 3168 n_rcu_torture_boost_failure = 0; 3169 n_rcu_torture_boosts = 0; 3170 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 3171 atomic_set(&rcu_torture_wcount[i], 0); 3172 for_each_possible_cpu(cpu) { 3173 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 3174 per_cpu(rcu_torture_count, cpu)[i] = 0; 3175 per_cpu(rcu_torture_batch, cpu)[i] = 0; 3176 } 3177 } 3178 err_segs_recorded = 0; 3179 rt_read_nsegs = 0; 3180 3181 /* Start up the kthreads. */ 3182 3183 rcu_torture_write_types(); 3184 firsterr = torture_create_kthread(rcu_torture_writer, NULL, 3185 writer_task); 3186 if (torture_init_error(firsterr)) 3187 goto unwind; 3188 if (nfakewriters > 0) { 3189 fakewriter_tasks = kcalloc(nfakewriters, 3190 sizeof(fakewriter_tasks[0]), 3191 GFP_KERNEL); 3192 if (fakewriter_tasks == NULL) { 3193 TOROUT_ERRSTRING("out of memory"); 3194 firsterr = -ENOMEM; 3195 goto unwind; 3196 } 3197 } 3198 for (i = 0; i < nfakewriters; i++) { 3199 firsterr = torture_create_kthread(rcu_torture_fakewriter, 3200 NULL, fakewriter_tasks[i]); 3201 if (torture_init_error(firsterr)) 3202 goto unwind; 3203 } 3204 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]), 3205 GFP_KERNEL); 3206 rcu_torture_reader_mbchk = kcalloc(nrealreaders, sizeof(*rcu_torture_reader_mbchk), 3207 GFP_KERNEL); 3208 if (!reader_tasks || !rcu_torture_reader_mbchk) { 3209 TOROUT_ERRSTRING("out of memory"); 3210 firsterr = -ENOMEM; 3211 goto unwind; 3212 } 3213 for (i = 0; i < nrealreaders; i++) { 3214 rcu_torture_reader_mbchk[i].rtc_chkrdr = -1; 3215 firsterr = torture_create_kthread(rcu_torture_reader, (void *)i, 3216 reader_tasks[i]); 3217 if (torture_init_error(firsterr)) 3218 goto unwind; 3219 } 3220 nrealnocbers = nocbs_nthreads; 3221 if (WARN_ON(nrealnocbers < 0)) 3222 nrealnocbers = 1; 3223 if (WARN_ON(nocbs_toggle < 0)) 3224 nocbs_toggle = HZ; 3225 if (nrealnocbers > 0) { 3226 nocb_tasks = kcalloc(nrealnocbers, sizeof(nocb_tasks[0]), GFP_KERNEL); 3227 if (nocb_tasks == NULL) { 3228 TOROUT_ERRSTRING("out of memory"); 3229 firsterr = -ENOMEM; 3230 goto unwind; 3231 } 3232 } else { 3233 nocb_tasks = NULL; 3234 } 3235 for (i = 0; i < nrealnocbers; i++) { 3236 firsterr = torture_create_kthread(rcu_nocb_toggle, NULL, nocb_tasks[i]); 3237 if (torture_init_error(firsterr)) 3238 goto unwind; 3239 } 3240 if (stat_interval > 0) { 3241 firsterr = torture_create_kthread(rcu_torture_stats, NULL, 3242 stats_task); 3243 if (torture_init_error(firsterr)) 3244 goto unwind; 3245 } 3246 if (test_no_idle_hz && shuffle_interval > 0) { 3247 firsterr = torture_shuffle_init(shuffle_interval * HZ); 3248 if (torture_init_error(firsterr)) 3249 goto unwind; 3250 } 3251 if (stutter < 0) 3252 stutter = 0; 3253 if (stutter) { 3254 int t; 3255 3256 t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ; 3257 firsterr = torture_stutter_init(stutter * HZ, t); 3258 if (torture_init_error(firsterr)) 3259 goto unwind; 3260 } 3261 if (fqs_duration < 0) 3262 fqs_duration = 0; 3263 if (fqs_duration) { 3264 /* Create the fqs thread */ 3265 firsterr = torture_create_kthread(rcu_torture_fqs, NULL, 3266 fqs_task); 3267 if (torture_init_error(firsterr)) 3268 goto unwind; 3269 } 3270 if (test_boost_interval < 1) 3271 test_boost_interval = 1; 3272 if (test_boost_duration < 2) 3273 test_boost_duration = 2; 3274 if (rcu_torture_can_boost()) { 3275 3276 boost_starttime = jiffies + test_boost_interval * HZ; 3277 3278 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE", 3279 rcutorture_booster_init, 3280 rcutorture_booster_cleanup); 3281 rcutor_hp = firsterr; 3282 if (torture_init_error(firsterr)) 3283 goto unwind; 3284 3285 // Testing RCU priority boosting requires rcutorture do 3286 // some serious abuse. Counter this by running ksoftirqd 3287 // at higher priority. 3288 if (IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)) { 3289 for_each_online_cpu(cpu) { 3290 struct sched_param sp; 3291 struct task_struct *t; 3292 3293 t = per_cpu(ksoftirqd, cpu); 3294 WARN_ON_ONCE(!t); 3295 sp.sched_priority = 2; 3296 sched_setscheduler_nocheck(t, SCHED_FIFO, &sp); 3297 } 3298 } 3299 } 3300 shutdown_jiffies = jiffies + shutdown_secs * HZ; 3301 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup); 3302 if (torture_init_error(firsterr)) 3303 goto unwind; 3304 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval, 3305 rcutorture_sync); 3306 if (torture_init_error(firsterr)) 3307 goto unwind; 3308 firsterr = rcu_torture_stall_init(); 3309 if (torture_init_error(firsterr)) 3310 goto unwind; 3311 firsterr = rcu_torture_fwd_prog_init(); 3312 if (torture_init_error(firsterr)) 3313 goto unwind; 3314 firsterr = rcu_torture_barrier_init(); 3315 if (torture_init_error(firsterr)) 3316 goto unwind; 3317 firsterr = rcu_torture_read_exit_init(); 3318 if (torture_init_error(firsterr)) 3319 goto unwind; 3320 if (object_debug) 3321 rcu_test_debug_objects(); 3322 torture_init_end(); 3323 return 0; 3324 3325 unwind: 3326 torture_init_end(); 3327 rcu_torture_cleanup(); 3328 if (shutdown_secs) { 3329 WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST)); 3330 kernel_power_off(); 3331 } 3332 return firsterr; 3333 } 3334 3335 module_init(rcu_torture_init); 3336 module_exit(rcu_torture_cleanup); 3337