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, "Duration of fqs bursts (us), 0 to disable"); 79 torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)"); 80 torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)"); 81 torture_param(int, fwd_progress, 1, "Number of grace-period forward progress tasks (0 to disable)"); 82 torture_param(int, fwd_progress_div, 4, "Fraction of CPU stall to wait"); 83 torture_param(int, fwd_progress_holdoff, 60, "Time between forward-progress tests (s)"); 84 torture_param(bool, fwd_progress_need_resched, 1, "Hide cond_resched() behind need_resched()"); 85 torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives"); 86 torture_param(bool, gp_cond_exp, false, "Use conditional/async expedited GP wait primitives"); 87 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives"); 88 torture_param(bool, gp_normal, false, "Use normal (non-expedited) GP wait primitives"); 89 torture_param(bool, gp_poll, false, "Use polling GP wait primitives"); 90 torture_param(bool, gp_poll_exp, false, "Use polling expedited GP wait primitives"); 91 torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives"); 92 torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers"); 93 torture_param(int, leakpointer, 0, "Leak pointer dereferences from readers"); 94 torture_param(int, n_barrier_cbs, 0, "# of callbacks/kthreads for barrier testing"); 95 torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads"); 96 torture_param(int, nreaders, -1, "Number of RCU reader threads"); 97 torture_param(int, object_debug, 0, "Enable debug-object double call_rcu() testing"); 98 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)"); 99 torture_param(int, onoff_interval, 0, "Time between CPU hotplugs (jiffies), 0=disable"); 100 torture_param(int, nocbs_nthreads, 0, "Number of NOCB toggle threads, 0 to disable"); 101 torture_param(int, nocbs_toggle, 1000, "Time between toggling nocb state (ms)"); 102 torture_param(int, read_exit_delay, 13, "Delay between read-then-exit episodes (s)"); 103 torture_param(int, read_exit_burst, 16, "# of read-then-exit bursts per episode, zero to disable"); 104 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles"); 105 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable."); 106 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable."); 107 torture_param(int, stall_cpu_holdoff, 10, "Time to wait before starting stall (s)."); 108 torture_param(bool, stall_no_softlockup, false, "Avoid softlockup warning during cpu stall."); 109 torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling."); 110 torture_param(int, stall_cpu_block, 0, "Sleep while stalling."); 111 torture_param(int, stall_gp_kthread, 0, "Grace-period kthread stall duration (s)."); 112 torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s"); 113 torture_param(int, stutter, 5, "Number of seconds to run/halt test"); 114 torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes."); 115 torture_param(int, test_boost_duration, 4, "Duration of each boost test, seconds."); 116 torture_param(int, test_boost_interval, 7, "Interval between boost tests, seconds."); 117 torture_param(bool, test_no_idle_hz, true, "Test support for tickless idle CPUs"); 118 torture_param(int, verbose, 1, "Enable verbose debugging printk()s"); 119 120 static char *torture_type = "rcu"; 121 module_param(torture_type, charp, 0444); 122 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, srcu, ...)"); 123 124 static int nrealnocbers; 125 static int nrealreaders; 126 static struct task_struct *writer_task; 127 static struct task_struct **fakewriter_tasks; 128 static struct task_struct **reader_tasks; 129 static struct task_struct **nocb_tasks; 130 static struct task_struct *stats_task; 131 static struct task_struct *fqs_task; 132 static struct task_struct *boost_tasks[NR_CPUS]; 133 static struct task_struct *stall_task; 134 static struct task_struct **fwd_prog_tasks; 135 static struct task_struct **barrier_cbs_tasks; 136 static struct task_struct *barrier_task; 137 static struct task_struct *read_exit_task; 138 139 #define RCU_TORTURE_PIPE_LEN 10 140 141 // Mailbox-like structure to check RCU global memory ordering. 142 struct rcu_torture_reader_check { 143 unsigned long rtc_myloops; 144 int rtc_chkrdr; 145 unsigned long rtc_chkloops; 146 int rtc_ready; 147 struct rcu_torture_reader_check *rtc_assigner; 148 } ____cacheline_internodealigned_in_smp; 149 150 // Update-side data structure used to check RCU readers. 151 struct rcu_torture { 152 struct rcu_head rtort_rcu; 153 int rtort_pipe_count; 154 struct list_head rtort_free; 155 int rtort_mbtest; 156 struct rcu_torture_reader_check *rtort_chkp; 157 }; 158 159 static LIST_HEAD(rcu_torture_freelist); 160 static struct rcu_torture __rcu *rcu_torture_current; 161 static unsigned long rcu_torture_current_version; 162 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN]; 163 static DEFINE_SPINLOCK(rcu_torture_lock); 164 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count); 165 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch); 166 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1]; 167 static struct rcu_torture_reader_check *rcu_torture_reader_mbchk; 168 static atomic_t n_rcu_torture_alloc; 169 static atomic_t n_rcu_torture_alloc_fail; 170 static atomic_t n_rcu_torture_free; 171 static atomic_t n_rcu_torture_mberror; 172 static atomic_t n_rcu_torture_mbchk_fail; 173 static atomic_t n_rcu_torture_mbchk_tries; 174 static atomic_t n_rcu_torture_error; 175 static long n_rcu_torture_barrier_error; 176 static long n_rcu_torture_boost_ktrerror; 177 static long n_rcu_torture_boost_rterror; 178 static long n_rcu_torture_boost_failure; 179 static long n_rcu_torture_boosts; 180 static atomic_long_t n_rcu_torture_timers; 181 static long n_barrier_attempts; 182 static long n_barrier_successes; /* did rcu_barrier test succeed? */ 183 static unsigned long n_read_exits; 184 static struct list_head rcu_torture_removed; 185 static unsigned long shutdown_jiffies; 186 static unsigned long start_gp_seq; 187 static atomic_long_t n_nocb_offload; 188 static atomic_long_t n_nocb_deoffload; 189 190 static int rcu_torture_writer_state; 191 #define RTWS_FIXED_DELAY 0 192 #define RTWS_DELAY 1 193 #define RTWS_REPLACE 2 194 #define RTWS_DEF_FREE 3 195 #define RTWS_EXP_SYNC 4 196 #define RTWS_COND_GET 5 197 #define RTWS_COND_GET_EXP 6 198 #define RTWS_COND_SYNC 7 199 #define RTWS_COND_SYNC_EXP 8 200 #define RTWS_POLL_GET 9 201 #define RTWS_POLL_GET_EXP 10 202 #define RTWS_POLL_WAIT 11 203 #define RTWS_POLL_WAIT_EXP 12 204 #define RTWS_SYNC 13 205 #define RTWS_STUTTER 14 206 #define RTWS_STOPPING 15 207 static const char * const rcu_torture_writer_state_names[] = { 208 "RTWS_FIXED_DELAY", 209 "RTWS_DELAY", 210 "RTWS_REPLACE", 211 "RTWS_DEF_FREE", 212 "RTWS_EXP_SYNC", 213 "RTWS_COND_GET", 214 "RTWS_COND_GET_EXP", 215 "RTWS_COND_SYNC", 216 "RTWS_COND_SYNC_EXP", 217 "RTWS_POLL_GET", 218 "RTWS_POLL_GET_EXP", 219 "RTWS_POLL_WAIT", 220 "RTWS_POLL_WAIT_EXP", 221 "RTWS_SYNC", 222 "RTWS_STUTTER", 223 "RTWS_STOPPING", 224 }; 225 226 /* Record reader segment types and duration for first failing read. */ 227 struct rt_read_seg { 228 int rt_readstate; 229 unsigned long rt_delay_jiffies; 230 unsigned long rt_delay_ms; 231 unsigned long rt_delay_us; 232 bool rt_preempted; 233 }; 234 static int err_segs_recorded; 235 static struct rt_read_seg err_segs[RCUTORTURE_RDR_MAX_SEGS]; 236 static int rt_read_nsegs; 237 238 static const char *rcu_torture_writer_state_getname(void) 239 { 240 unsigned int i = READ_ONCE(rcu_torture_writer_state); 241 242 if (i >= ARRAY_SIZE(rcu_torture_writer_state_names)) 243 return "???"; 244 return rcu_torture_writer_state_names[i]; 245 } 246 247 #ifdef CONFIG_RCU_TRACE 248 static u64 notrace rcu_trace_clock_local(void) 249 { 250 u64 ts = trace_clock_local(); 251 252 (void)do_div(ts, NSEC_PER_USEC); 253 return ts; 254 } 255 #else /* #ifdef CONFIG_RCU_TRACE */ 256 static u64 notrace rcu_trace_clock_local(void) 257 { 258 return 0ULL; 259 } 260 #endif /* #else #ifdef CONFIG_RCU_TRACE */ 261 262 /* 263 * Stop aggressive CPU-hog tests a bit before the end of the test in order 264 * to avoid interfering with test shutdown. 265 */ 266 static bool shutdown_time_arrived(void) 267 { 268 return shutdown_secs && time_after(jiffies, shutdown_jiffies - 30 * HZ); 269 } 270 271 static unsigned long boost_starttime; /* jiffies of next boost test start. */ 272 static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */ 273 /* and boost task create/destroy. */ 274 static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */ 275 static bool barrier_phase; /* Test phase. */ 276 static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */ 277 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */ 278 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq); 279 280 static atomic_t rcu_fwd_cb_nodelay; /* Short rcu_torture_delay() delays. */ 281 282 /* 283 * Allocate an element from the rcu_tortures pool. 284 */ 285 static struct rcu_torture * 286 rcu_torture_alloc(void) 287 { 288 struct list_head *p; 289 290 spin_lock_bh(&rcu_torture_lock); 291 if (list_empty(&rcu_torture_freelist)) { 292 atomic_inc(&n_rcu_torture_alloc_fail); 293 spin_unlock_bh(&rcu_torture_lock); 294 return NULL; 295 } 296 atomic_inc(&n_rcu_torture_alloc); 297 p = rcu_torture_freelist.next; 298 list_del_init(p); 299 spin_unlock_bh(&rcu_torture_lock); 300 return container_of(p, struct rcu_torture, rtort_free); 301 } 302 303 /* 304 * Free an element to the rcu_tortures pool. 305 */ 306 static void 307 rcu_torture_free(struct rcu_torture *p) 308 { 309 atomic_inc(&n_rcu_torture_free); 310 spin_lock_bh(&rcu_torture_lock); 311 list_add_tail(&p->rtort_free, &rcu_torture_freelist); 312 spin_unlock_bh(&rcu_torture_lock); 313 } 314 315 /* 316 * Operations vector for selecting different types of tests. 317 */ 318 319 struct rcu_torture_ops { 320 int ttype; 321 void (*init)(void); 322 void (*cleanup)(void); 323 int (*readlock)(void); 324 void (*read_delay)(struct torture_random_state *rrsp, 325 struct rt_read_seg *rtrsp); 326 void (*readunlock)(int idx); 327 int (*readlock_held)(void); 328 unsigned long (*get_gp_seq)(void); 329 unsigned long (*gp_diff)(unsigned long new, unsigned long old); 330 void (*deferred_free)(struct rcu_torture *p); 331 void (*sync)(void); 332 void (*exp_sync)(void); 333 unsigned long (*get_gp_state_exp)(void); 334 unsigned long (*start_gp_poll_exp)(void); 335 bool (*poll_gp_state_exp)(unsigned long oldstate); 336 void (*cond_sync_exp)(unsigned long oldstate); 337 unsigned long (*get_gp_state)(void); 338 unsigned long (*get_gp_completed)(void); 339 unsigned long (*start_gp_poll)(void); 340 bool (*poll_gp_state)(unsigned long oldstate); 341 void (*cond_sync)(unsigned long oldstate); 342 call_rcu_func_t call; 343 void (*cb_barrier)(void); 344 void (*fqs)(void); 345 void (*stats)(void); 346 void (*gp_kthread_dbg)(void); 347 bool (*check_boost_failed)(unsigned long gp_state, int *cpup); 348 int (*stall_dur)(void); 349 long cbflood_max; 350 int irq_capable; 351 int can_boost; 352 int extendables; 353 int slow_gps; 354 int no_pi_lock; 355 const char *name; 356 }; 357 358 static struct rcu_torture_ops *cur_ops; 359 360 /* 361 * Definitions for rcu torture testing. 362 */ 363 364 static int torture_readlock_not_held(void) 365 { 366 return rcu_read_lock_bh_held() || rcu_read_lock_sched_held(); 367 } 368 369 static int rcu_torture_read_lock(void) __acquires(RCU) 370 { 371 rcu_read_lock(); 372 return 0; 373 } 374 375 static void 376 rcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp) 377 { 378 unsigned long started; 379 unsigned long completed; 380 const unsigned long shortdelay_us = 200; 381 unsigned long longdelay_ms = 300; 382 unsigned long long ts; 383 384 /* We want a short delay sometimes to make a reader delay the grace 385 * period, and we want a long delay occasionally to trigger 386 * force_quiescent_state. */ 387 388 if (!atomic_read(&rcu_fwd_cb_nodelay) && 389 !(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) { 390 started = cur_ops->get_gp_seq(); 391 ts = rcu_trace_clock_local(); 392 if (preempt_count() & (SOFTIRQ_MASK | HARDIRQ_MASK)) 393 longdelay_ms = 5; /* Avoid triggering BH limits. */ 394 mdelay(longdelay_ms); 395 rtrsp->rt_delay_ms = longdelay_ms; 396 completed = cur_ops->get_gp_seq(); 397 do_trace_rcu_torture_read(cur_ops->name, NULL, ts, 398 started, completed); 399 } 400 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) { 401 udelay(shortdelay_us); 402 rtrsp->rt_delay_us = shortdelay_us; 403 } 404 if (!preempt_count() && 405 !(torture_random(rrsp) % (nrealreaders * 500))) { 406 torture_preempt_schedule(); /* QS only if preemptible. */ 407 rtrsp->rt_preempted = true; 408 } 409 } 410 411 static void rcu_torture_read_unlock(int idx) __releases(RCU) 412 { 413 rcu_read_unlock(); 414 } 415 416 /* 417 * Update callback in the pipe. This should be invoked after a grace period. 418 */ 419 static bool 420 rcu_torture_pipe_update_one(struct rcu_torture *rp) 421 { 422 int i; 423 struct rcu_torture_reader_check *rtrcp = READ_ONCE(rp->rtort_chkp); 424 425 if (rtrcp) { 426 WRITE_ONCE(rp->rtort_chkp, NULL); 427 smp_store_release(&rtrcp->rtc_ready, 1); // Pair with smp_load_acquire(). 428 } 429 i = READ_ONCE(rp->rtort_pipe_count); 430 if (i > RCU_TORTURE_PIPE_LEN) 431 i = RCU_TORTURE_PIPE_LEN; 432 atomic_inc(&rcu_torture_wcount[i]); 433 WRITE_ONCE(rp->rtort_pipe_count, i + 1); 434 if (rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) { 435 rp->rtort_mbtest = 0; 436 return true; 437 } 438 return false; 439 } 440 441 /* 442 * Update all callbacks in the pipe. Suitable for synchronous grace-period 443 * primitives. 444 */ 445 static void 446 rcu_torture_pipe_update(struct rcu_torture *old_rp) 447 { 448 struct rcu_torture *rp; 449 struct rcu_torture *rp1; 450 451 if (old_rp) 452 list_add(&old_rp->rtort_free, &rcu_torture_removed); 453 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) { 454 if (rcu_torture_pipe_update_one(rp)) { 455 list_del(&rp->rtort_free); 456 rcu_torture_free(rp); 457 } 458 } 459 } 460 461 static void 462 rcu_torture_cb(struct rcu_head *p) 463 { 464 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu); 465 466 if (torture_must_stop_irq()) { 467 /* Test is ending, just drop callbacks on the floor. */ 468 /* The next initialization will pick up the pieces. */ 469 return; 470 } 471 if (rcu_torture_pipe_update_one(rp)) 472 rcu_torture_free(rp); 473 else 474 cur_ops->deferred_free(rp); 475 } 476 477 static unsigned long rcu_no_completed(void) 478 { 479 return 0; 480 } 481 482 static void rcu_torture_deferred_free(struct rcu_torture *p) 483 { 484 call_rcu(&p->rtort_rcu, rcu_torture_cb); 485 } 486 487 static void rcu_sync_torture_init(void) 488 { 489 INIT_LIST_HEAD(&rcu_torture_removed); 490 } 491 492 static struct rcu_torture_ops rcu_ops = { 493 .ttype = RCU_FLAVOR, 494 .init = rcu_sync_torture_init, 495 .readlock = rcu_torture_read_lock, 496 .read_delay = rcu_read_delay, 497 .readunlock = rcu_torture_read_unlock, 498 .readlock_held = torture_readlock_not_held, 499 .get_gp_seq = rcu_get_gp_seq, 500 .gp_diff = rcu_seq_diff, 501 .deferred_free = rcu_torture_deferred_free, 502 .sync = synchronize_rcu, 503 .exp_sync = synchronize_rcu_expedited, 504 .get_gp_state = get_state_synchronize_rcu, 505 .get_gp_completed = get_completed_synchronize_rcu, 506 .start_gp_poll = start_poll_synchronize_rcu, 507 .poll_gp_state = poll_state_synchronize_rcu, 508 .cond_sync = cond_synchronize_rcu, 509 .get_gp_state_exp = get_state_synchronize_rcu, 510 .start_gp_poll_exp = start_poll_synchronize_rcu_expedited, 511 .poll_gp_state_exp = poll_state_synchronize_rcu, 512 .cond_sync_exp = cond_synchronize_rcu_expedited, 513 .call = call_rcu, 514 .cb_barrier = rcu_barrier, 515 .fqs = rcu_force_quiescent_state, 516 .stats = NULL, 517 .gp_kthread_dbg = show_rcu_gp_kthreads, 518 .check_boost_failed = rcu_check_boost_fail, 519 .stall_dur = rcu_jiffies_till_stall_check, 520 .irq_capable = 1, 521 .can_boost = IS_ENABLED(CONFIG_RCU_BOOST), 522 .extendables = RCUTORTURE_MAX_EXTEND, 523 .name = "rcu" 524 }; 525 526 /* 527 * Don't even think about trying any of these in real life!!! 528 * The names includes "busted", and they really means it! 529 * The only purpose of these functions is to provide a buggy RCU 530 * implementation to make sure that rcutorture correctly emits 531 * buggy-RCU error messages. 532 */ 533 static void rcu_busted_torture_deferred_free(struct rcu_torture *p) 534 { 535 /* This is a deliberate bug for testing purposes only! */ 536 rcu_torture_cb(&p->rtort_rcu); 537 } 538 539 static void synchronize_rcu_busted(void) 540 { 541 /* This is a deliberate bug for testing purposes only! */ 542 } 543 544 static void 545 call_rcu_busted(struct rcu_head *head, rcu_callback_t func) 546 { 547 /* This is a deliberate bug for testing purposes only! */ 548 func(head); 549 } 550 551 static struct rcu_torture_ops rcu_busted_ops = { 552 .ttype = INVALID_RCU_FLAVOR, 553 .init = rcu_sync_torture_init, 554 .readlock = rcu_torture_read_lock, 555 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 556 .readunlock = rcu_torture_read_unlock, 557 .readlock_held = torture_readlock_not_held, 558 .get_gp_seq = rcu_no_completed, 559 .deferred_free = rcu_busted_torture_deferred_free, 560 .sync = synchronize_rcu_busted, 561 .exp_sync = synchronize_rcu_busted, 562 .call = call_rcu_busted, 563 .cb_barrier = NULL, 564 .fqs = NULL, 565 .stats = NULL, 566 .irq_capable = 1, 567 .name = "busted" 568 }; 569 570 /* 571 * Definitions for srcu torture testing. 572 */ 573 574 DEFINE_STATIC_SRCU(srcu_ctl); 575 static struct srcu_struct srcu_ctld; 576 static struct srcu_struct *srcu_ctlp = &srcu_ctl; 577 578 static int srcu_torture_read_lock(void) __acquires(srcu_ctlp) 579 { 580 return srcu_read_lock(srcu_ctlp); 581 } 582 583 static void 584 srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp) 585 { 586 long delay; 587 const long uspertick = 1000000 / HZ; 588 const long longdelay = 10; 589 590 /* We want there to be long-running readers, but not all the time. */ 591 592 delay = torture_random(rrsp) % 593 (nrealreaders * 2 * longdelay * uspertick); 594 if (!delay && in_task()) { 595 schedule_timeout_interruptible(longdelay); 596 rtrsp->rt_delay_jiffies = longdelay; 597 } else { 598 rcu_read_delay(rrsp, rtrsp); 599 } 600 } 601 602 static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp) 603 { 604 srcu_read_unlock(srcu_ctlp, idx); 605 } 606 607 static int torture_srcu_read_lock_held(void) 608 { 609 return srcu_read_lock_held(srcu_ctlp); 610 } 611 612 static unsigned long srcu_torture_completed(void) 613 { 614 return srcu_batches_completed(srcu_ctlp); 615 } 616 617 static void srcu_torture_deferred_free(struct rcu_torture *rp) 618 { 619 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb); 620 } 621 622 static void srcu_torture_synchronize(void) 623 { 624 synchronize_srcu(srcu_ctlp); 625 } 626 627 static unsigned long srcu_torture_get_gp_state(void) 628 { 629 return get_state_synchronize_srcu(srcu_ctlp); 630 } 631 632 static unsigned long srcu_torture_start_gp_poll(void) 633 { 634 return start_poll_synchronize_srcu(srcu_ctlp); 635 } 636 637 static bool srcu_torture_poll_gp_state(unsigned long oldstate) 638 { 639 return poll_state_synchronize_srcu(srcu_ctlp, oldstate); 640 } 641 642 static void srcu_torture_call(struct rcu_head *head, 643 rcu_callback_t func) 644 { 645 call_srcu(srcu_ctlp, head, func); 646 } 647 648 static void srcu_torture_barrier(void) 649 { 650 srcu_barrier(srcu_ctlp); 651 } 652 653 static void srcu_torture_stats(void) 654 { 655 srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG); 656 } 657 658 static void srcu_torture_synchronize_expedited(void) 659 { 660 synchronize_srcu_expedited(srcu_ctlp); 661 } 662 663 static struct rcu_torture_ops srcu_ops = { 664 .ttype = SRCU_FLAVOR, 665 .init = rcu_sync_torture_init, 666 .readlock = srcu_torture_read_lock, 667 .read_delay = srcu_read_delay, 668 .readunlock = srcu_torture_read_unlock, 669 .readlock_held = torture_srcu_read_lock_held, 670 .get_gp_seq = srcu_torture_completed, 671 .deferred_free = srcu_torture_deferred_free, 672 .sync = srcu_torture_synchronize, 673 .exp_sync = srcu_torture_synchronize_expedited, 674 .get_gp_state = srcu_torture_get_gp_state, 675 .start_gp_poll = srcu_torture_start_gp_poll, 676 .poll_gp_state = srcu_torture_poll_gp_state, 677 .call = srcu_torture_call, 678 .cb_barrier = srcu_torture_barrier, 679 .stats = srcu_torture_stats, 680 .cbflood_max = 50000, 681 .irq_capable = 1, 682 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU), 683 .name = "srcu" 684 }; 685 686 static void srcu_torture_init(void) 687 { 688 rcu_sync_torture_init(); 689 WARN_ON(init_srcu_struct(&srcu_ctld)); 690 srcu_ctlp = &srcu_ctld; 691 } 692 693 static void srcu_torture_cleanup(void) 694 { 695 cleanup_srcu_struct(&srcu_ctld); 696 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */ 697 } 698 699 /* As above, but dynamically allocated. */ 700 static struct rcu_torture_ops srcud_ops = { 701 .ttype = SRCU_FLAVOR, 702 .init = srcu_torture_init, 703 .cleanup = srcu_torture_cleanup, 704 .readlock = srcu_torture_read_lock, 705 .read_delay = srcu_read_delay, 706 .readunlock = srcu_torture_read_unlock, 707 .readlock_held = torture_srcu_read_lock_held, 708 .get_gp_seq = srcu_torture_completed, 709 .deferred_free = srcu_torture_deferred_free, 710 .sync = srcu_torture_synchronize, 711 .exp_sync = srcu_torture_synchronize_expedited, 712 .call = srcu_torture_call, 713 .cb_barrier = srcu_torture_barrier, 714 .stats = srcu_torture_stats, 715 .cbflood_max = 50000, 716 .irq_capable = 1, 717 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU), 718 .name = "srcud" 719 }; 720 721 /* As above, but broken due to inappropriate reader extension. */ 722 static struct rcu_torture_ops busted_srcud_ops = { 723 .ttype = SRCU_FLAVOR, 724 .init = srcu_torture_init, 725 .cleanup = srcu_torture_cleanup, 726 .readlock = srcu_torture_read_lock, 727 .read_delay = rcu_read_delay, 728 .readunlock = srcu_torture_read_unlock, 729 .readlock_held = torture_srcu_read_lock_held, 730 .get_gp_seq = srcu_torture_completed, 731 .deferred_free = srcu_torture_deferred_free, 732 .sync = srcu_torture_synchronize, 733 .exp_sync = srcu_torture_synchronize_expedited, 734 .call = srcu_torture_call, 735 .cb_barrier = srcu_torture_barrier, 736 .stats = srcu_torture_stats, 737 .irq_capable = 1, 738 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU), 739 .extendables = RCUTORTURE_MAX_EXTEND, 740 .name = "busted_srcud" 741 }; 742 743 /* 744 * Definitions for trivial CONFIG_PREEMPT=n-only torture testing. 745 * This implementation does not necessarily work well with CPU hotplug. 746 */ 747 748 static void synchronize_rcu_trivial(void) 749 { 750 int cpu; 751 752 for_each_online_cpu(cpu) { 753 rcutorture_sched_setaffinity(current->pid, cpumask_of(cpu)); 754 WARN_ON_ONCE(raw_smp_processor_id() != cpu); 755 } 756 } 757 758 static int rcu_torture_read_lock_trivial(void) __acquires(RCU) 759 { 760 preempt_disable(); 761 return 0; 762 } 763 764 static void rcu_torture_read_unlock_trivial(int idx) __releases(RCU) 765 { 766 preempt_enable(); 767 } 768 769 static struct rcu_torture_ops trivial_ops = { 770 .ttype = RCU_TRIVIAL_FLAVOR, 771 .init = rcu_sync_torture_init, 772 .readlock = rcu_torture_read_lock_trivial, 773 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 774 .readunlock = rcu_torture_read_unlock_trivial, 775 .readlock_held = torture_readlock_not_held, 776 .get_gp_seq = rcu_no_completed, 777 .sync = synchronize_rcu_trivial, 778 .exp_sync = synchronize_rcu_trivial, 779 .fqs = NULL, 780 .stats = NULL, 781 .irq_capable = 1, 782 .name = "trivial" 783 }; 784 785 #ifdef CONFIG_TASKS_RCU 786 787 /* 788 * Definitions for RCU-tasks torture testing. 789 */ 790 791 static int tasks_torture_read_lock(void) 792 { 793 return 0; 794 } 795 796 static void tasks_torture_read_unlock(int idx) 797 { 798 } 799 800 static void rcu_tasks_torture_deferred_free(struct rcu_torture *p) 801 { 802 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb); 803 } 804 805 static void synchronize_rcu_mult_test(void) 806 { 807 synchronize_rcu_mult(call_rcu_tasks, call_rcu); 808 } 809 810 static struct rcu_torture_ops tasks_ops = { 811 .ttype = RCU_TASKS_FLAVOR, 812 .init = rcu_sync_torture_init, 813 .readlock = tasks_torture_read_lock, 814 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 815 .readunlock = tasks_torture_read_unlock, 816 .get_gp_seq = rcu_no_completed, 817 .deferred_free = rcu_tasks_torture_deferred_free, 818 .sync = synchronize_rcu_tasks, 819 .exp_sync = synchronize_rcu_mult_test, 820 .call = call_rcu_tasks, 821 .cb_barrier = rcu_barrier_tasks, 822 .gp_kthread_dbg = show_rcu_tasks_classic_gp_kthread, 823 .fqs = NULL, 824 .stats = NULL, 825 .irq_capable = 1, 826 .slow_gps = 1, 827 .name = "tasks" 828 }; 829 830 #define TASKS_OPS &tasks_ops, 831 832 #else // #ifdef CONFIG_TASKS_RCU 833 834 #define TASKS_OPS 835 836 #endif // #else #ifdef CONFIG_TASKS_RCU 837 838 839 #ifdef CONFIG_TASKS_RUDE_RCU 840 841 /* 842 * Definitions for rude RCU-tasks torture testing. 843 */ 844 845 static void rcu_tasks_rude_torture_deferred_free(struct rcu_torture *p) 846 { 847 call_rcu_tasks_rude(&p->rtort_rcu, rcu_torture_cb); 848 } 849 850 static struct rcu_torture_ops tasks_rude_ops = { 851 .ttype = RCU_TASKS_RUDE_FLAVOR, 852 .init = rcu_sync_torture_init, 853 .readlock = rcu_torture_read_lock_trivial, 854 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 855 .readunlock = rcu_torture_read_unlock_trivial, 856 .get_gp_seq = rcu_no_completed, 857 .deferred_free = rcu_tasks_rude_torture_deferred_free, 858 .sync = synchronize_rcu_tasks_rude, 859 .exp_sync = synchronize_rcu_tasks_rude, 860 .call = call_rcu_tasks_rude, 861 .cb_barrier = rcu_barrier_tasks_rude, 862 .gp_kthread_dbg = show_rcu_tasks_rude_gp_kthread, 863 .cbflood_max = 50000, 864 .fqs = NULL, 865 .stats = NULL, 866 .irq_capable = 1, 867 .name = "tasks-rude" 868 }; 869 870 #define TASKS_RUDE_OPS &tasks_rude_ops, 871 872 #else // #ifdef CONFIG_TASKS_RUDE_RCU 873 874 #define TASKS_RUDE_OPS 875 876 #endif // #else #ifdef CONFIG_TASKS_RUDE_RCU 877 878 879 #ifdef CONFIG_TASKS_TRACE_RCU 880 881 /* 882 * Definitions for tracing RCU-tasks torture testing. 883 */ 884 885 static int tasks_tracing_torture_read_lock(void) 886 { 887 rcu_read_lock_trace(); 888 return 0; 889 } 890 891 static void tasks_tracing_torture_read_unlock(int idx) 892 { 893 rcu_read_unlock_trace(); 894 } 895 896 static void rcu_tasks_tracing_torture_deferred_free(struct rcu_torture *p) 897 { 898 call_rcu_tasks_trace(&p->rtort_rcu, rcu_torture_cb); 899 } 900 901 static struct rcu_torture_ops tasks_tracing_ops = { 902 .ttype = RCU_TASKS_TRACING_FLAVOR, 903 .init = rcu_sync_torture_init, 904 .readlock = tasks_tracing_torture_read_lock, 905 .read_delay = srcu_read_delay, /* just reuse srcu's version. */ 906 .readunlock = tasks_tracing_torture_read_unlock, 907 .readlock_held = rcu_read_lock_trace_held, 908 .get_gp_seq = rcu_no_completed, 909 .deferred_free = rcu_tasks_tracing_torture_deferred_free, 910 .sync = synchronize_rcu_tasks_trace, 911 .exp_sync = synchronize_rcu_tasks_trace, 912 .call = call_rcu_tasks_trace, 913 .cb_barrier = rcu_barrier_tasks_trace, 914 .gp_kthread_dbg = show_rcu_tasks_trace_gp_kthread, 915 .cbflood_max = 50000, 916 .fqs = NULL, 917 .stats = NULL, 918 .irq_capable = 1, 919 .slow_gps = 1, 920 .name = "tasks-tracing" 921 }; 922 923 #define TASKS_TRACING_OPS &tasks_tracing_ops, 924 925 #else // #ifdef CONFIG_TASKS_TRACE_RCU 926 927 #define TASKS_TRACING_OPS 928 929 #endif // #else #ifdef CONFIG_TASKS_TRACE_RCU 930 931 932 static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old) 933 { 934 if (!cur_ops->gp_diff) 935 return new - old; 936 return cur_ops->gp_diff(new, old); 937 } 938 939 /* 940 * RCU torture priority-boost testing. Runs one real-time thread per 941 * CPU for moderate bursts, repeatedly starting grace periods and waiting 942 * for them to complete. If a given grace period takes too long, we assume 943 * that priority inversion has occurred. 944 */ 945 946 static int old_rt_runtime = -1; 947 948 static void rcu_torture_disable_rt_throttle(void) 949 { 950 /* 951 * Disable RT throttling so that rcutorture's boost threads don't get 952 * throttled. Only possible if rcutorture is built-in otherwise the 953 * user should manually do this by setting the sched_rt_period_us and 954 * sched_rt_runtime sysctls. 955 */ 956 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime != -1) 957 return; 958 959 old_rt_runtime = sysctl_sched_rt_runtime; 960 sysctl_sched_rt_runtime = -1; 961 } 962 963 static void rcu_torture_enable_rt_throttle(void) 964 { 965 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime == -1) 966 return; 967 968 sysctl_sched_rt_runtime = old_rt_runtime; 969 old_rt_runtime = -1; 970 } 971 972 static bool rcu_torture_boost_failed(unsigned long gp_state, unsigned long *start) 973 { 974 int cpu; 975 static int dbg_done; 976 unsigned long end = jiffies; 977 bool gp_done; 978 unsigned long j; 979 static unsigned long last_persist; 980 unsigned long lp; 981 unsigned long mininterval = test_boost_duration * HZ - HZ / 2; 982 983 if (end - *start > mininterval) { 984 // Recheck after checking time to avoid false positives. 985 smp_mb(); // Time check before grace-period check. 986 if (cur_ops->poll_gp_state(gp_state)) 987 return false; // passed, though perhaps just barely 988 if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, &cpu)) { 989 // At most one persisted message per boost test. 990 j = jiffies; 991 lp = READ_ONCE(last_persist); 992 if (time_after(j, lp + mininterval) && cmpxchg(&last_persist, lp, j) == lp) 993 pr_info("Boost inversion persisted: No QS from CPU %d\n", cpu); 994 return false; // passed on a technicality 995 } 996 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed"); 997 n_rcu_torture_boost_failure++; 998 if (!xchg(&dbg_done, 1) && cur_ops->gp_kthread_dbg) { 999 pr_info("Boost inversion thread ->rt_priority %u gp_state %lu jiffies %lu\n", 1000 current->rt_priority, gp_state, end - *start); 1001 cur_ops->gp_kthread_dbg(); 1002 // Recheck after print to flag grace period ending during splat. 1003 gp_done = cur_ops->poll_gp_state(gp_state); 1004 pr_info("Boost inversion: GP %lu %s.\n", gp_state, 1005 gp_done ? "ended already" : "still pending"); 1006 1007 } 1008 1009 return true; // failed 1010 } else if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, NULL)) { 1011 *start = jiffies; 1012 } 1013 1014 return false; // passed 1015 } 1016 1017 static int rcu_torture_boost(void *arg) 1018 { 1019 unsigned long endtime; 1020 unsigned long gp_state; 1021 unsigned long gp_state_time; 1022 unsigned long oldstarttime; 1023 1024 VERBOSE_TOROUT_STRING("rcu_torture_boost started"); 1025 1026 /* Set real-time priority. */ 1027 sched_set_fifo_low(current); 1028 1029 /* Each pass through the following loop does one boost-test cycle. */ 1030 do { 1031 bool failed = false; // Test failed already in this test interval 1032 bool gp_initiated = false; 1033 1034 if (kthread_should_stop()) 1035 goto checkwait; 1036 1037 /* Wait for the next test interval. */ 1038 oldstarttime = READ_ONCE(boost_starttime); 1039 while (time_before(jiffies, oldstarttime)) { 1040 schedule_timeout_interruptible(oldstarttime - jiffies); 1041 if (stutter_wait("rcu_torture_boost")) 1042 sched_set_fifo_low(current); 1043 if (torture_must_stop()) 1044 goto checkwait; 1045 } 1046 1047 // Do one boost-test interval. 1048 endtime = oldstarttime + test_boost_duration * HZ; 1049 while (time_before(jiffies, endtime)) { 1050 // Has current GP gone too long? 1051 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state)) 1052 failed = rcu_torture_boost_failed(gp_state, &gp_state_time); 1053 // If we don't have a grace period in flight, start one. 1054 if (!gp_initiated || cur_ops->poll_gp_state(gp_state)) { 1055 gp_state = cur_ops->start_gp_poll(); 1056 gp_initiated = true; 1057 gp_state_time = jiffies; 1058 } 1059 if (stutter_wait("rcu_torture_boost")) { 1060 sched_set_fifo_low(current); 1061 // If the grace period already ended, 1062 // we don't know when that happened, so 1063 // start over. 1064 if (cur_ops->poll_gp_state(gp_state)) 1065 gp_initiated = false; 1066 } 1067 if (torture_must_stop()) 1068 goto checkwait; 1069 } 1070 1071 // In case the grace period extended beyond the end of the loop. 1072 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state)) 1073 rcu_torture_boost_failed(gp_state, &gp_state_time); 1074 1075 /* 1076 * Set the start time of the next test interval. 1077 * Yes, this is vulnerable to long delays, but such 1078 * delays simply cause a false negative for the next 1079 * interval. Besides, we are running at RT priority, 1080 * so delays should be relatively rare. 1081 */ 1082 while (oldstarttime == READ_ONCE(boost_starttime) && !kthread_should_stop()) { 1083 if (mutex_trylock(&boost_mutex)) { 1084 if (oldstarttime == boost_starttime) { 1085 WRITE_ONCE(boost_starttime, 1086 jiffies + test_boost_interval * HZ); 1087 n_rcu_torture_boosts++; 1088 } 1089 mutex_unlock(&boost_mutex); 1090 break; 1091 } 1092 schedule_timeout_uninterruptible(1); 1093 } 1094 1095 /* Go do the stutter. */ 1096 checkwait: if (stutter_wait("rcu_torture_boost")) 1097 sched_set_fifo_low(current); 1098 } while (!torture_must_stop()); 1099 1100 /* Clean up and exit. */ 1101 while (!kthread_should_stop()) { 1102 torture_shutdown_absorb("rcu_torture_boost"); 1103 schedule_timeout_uninterruptible(1); 1104 } 1105 torture_kthread_stopping("rcu_torture_boost"); 1106 return 0; 1107 } 1108 1109 /* 1110 * RCU torture force-quiescent-state kthread. Repeatedly induces 1111 * bursts of calls to force_quiescent_state(), increasing the probability 1112 * of occurrence of some important types of race conditions. 1113 */ 1114 static int 1115 rcu_torture_fqs(void *arg) 1116 { 1117 unsigned long fqs_resume_time; 1118 int fqs_burst_remaining; 1119 int oldnice = task_nice(current); 1120 1121 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started"); 1122 do { 1123 fqs_resume_time = jiffies + fqs_stutter * HZ; 1124 while (time_before(jiffies, fqs_resume_time) && 1125 !kthread_should_stop()) { 1126 schedule_timeout_interruptible(1); 1127 } 1128 fqs_burst_remaining = fqs_duration; 1129 while (fqs_burst_remaining > 0 && 1130 !kthread_should_stop()) { 1131 cur_ops->fqs(); 1132 udelay(fqs_holdoff); 1133 fqs_burst_remaining -= fqs_holdoff; 1134 } 1135 if (stutter_wait("rcu_torture_fqs")) 1136 sched_set_normal(current, oldnice); 1137 } while (!torture_must_stop()); 1138 torture_kthread_stopping("rcu_torture_fqs"); 1139 return 0; 1140 } 1141 1142 // Used by writers to randomly choose from the available grace-period primitives. 1143 static int synctype[ARRAY_SIZE(rcu_torture_writer_state_names)] = { }; 1144 static int nsynctypes; 1145 1146 /* 1147 * Determine which grace-period primitives are available. 1148 */ 1149 static void rcu_torture_write_types(void) 1150 { 1151 bool gp_cond1 = gp_cond, gp_cond_exp1 = gp_cond_exp, gp_exp1 = gp_exp; 1152 bool gp_poll_exp1 = gp_poll_exp, gp_normal1 = gp_normal, gp_poll1 = gp_poll; 1153 bool gp_sync1 = gp_sync; 1154 1155 /* Initialize synctype[] array. If none set, take default. */ 1156 if (!gp_cond1 && !gp_cond_exp1 && !gp_exp1 && !gp_poll_exp && 1157 !gp_normal1 && !gp_poll1 && !gp_sync1) 1158 gp_cond1 = gp_cond_exp1 = gp_exp1 = gp_poll_exp1 = 1159 gp_normal1 = gp_poll1 = gp_sync1 = true; 1160 if (gp_cond1 && cur_ops->get_gp_state && cur_ops->cond_sync) { 1161 synctype[nsynctypes++] = RTWS_COND_GET; 1162 pr_info("%s: Testing conditional GPs.\n", __func__); 1163 } else if (gp_cond && (!cur_ops->get_gp_state || !cur_ops->cond_sync)) { 1164 pr_alert("%s: gp_cond without primitives.\n", __func__); 1165 } 1166 if (gp_cond_exp1 && cur_ops->get_gp_state_exp && cur_ops->cond_sync_exp) { 1167 synctype[nsynctypes++] = RTWS_COND_GET_EXP; 1168 pr_info("%s: Testing conditional expedited GPs.\n", __func__); 1169 } else if (gp_cond_exp && (!cur_ops->get_gp_state_exp || !cur_ops->cond_sync_exp)) { 1170 pr_alert("%s: gp_cond_exp without primitives.\n", __func__); 1171 } 1172 if (gp_exp1 && cur_ops->exp_sync) { 1173 synctype[nsynctypes++] = RTWS_EXP_SYNC; 1174 pr_info("%s: Testing expedited GPs.\n", __func__); 1175 } else if (gp_exp && !cur_ops->exp_sync) { 1176 pr_alert("%s: gp_exp without primitives.\n", __func__); 1177 } 1178 if (gp_normal1 && cur_ops->deferred_free) { 1179 synctype[nsynctypes++] = RTWS_DEF_FREE; 1180 pr_info("%s: Testing asynchronous GPs.\n", __func__); 1181 } else if (gp_normal && !cur_ops->deferred_free) { 1182 pr_alert("%s: gp_normal without primitives.\n", __func__); 1183 } 1184 if (gp_poll1 && cur_ops->start_gp_poll && cur_ops->poll_gp_state) { 1185 synctype[nsynctypes++] = RTWS_POLL_GET; 1186 pr_info("%s: Testing polling GPs.\n", __func__); 1187 } else if (gp_poll && (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)) { 1188 pr_alert("%s: gp_poll without primitives.\n", __func__); 1189 } 1190 if (gp_poll_exp1 && cur_ops->start_gp_poll_exp && cur_ops->poll_gp_state_exp) { 1191 synctype[nsynctypes++] = RTWS_POLL_GET_EXP; 1192 pr_info("%s: Testing polling expedited GPs.\n", __func__); 1193 } else if (gp_poll_exp && (!cur_ops->start_gp_poll_exp || !cur_ops->poll_gp_state_exp)) { 1194 pr_alert("%s: gp_poll_exp without primitives.\n", __func__); 1195 } 1196 if (gp_sync1 && cur_ops->sync) { 1197 synctype[nsynctypes++] = RTWS_SYNC; 1198 pr_info("%s: Testing normal GPs.\n", __func__); 1199 } else if (gp_sync && !cur_ops->sync) { 1200 pr_alert("%s: gp_sync without primitives.\n", __func__); 1201 } 1202 } 1203 1204 /* 1205 * RCU torture writer kthread. Repeatedly substitutes a new structure 1206 * for that pointed to by rcu_torture_current, freeing the old structure 1207 * after a series of grace periods (the "pipeline"). 1208 */ 1209 static int 1210 rcu_torture_writer(void *arg) 1211 { 1212 bool boot_ended; 1213 bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal(); 1214 unsigned long cookie; 1215 int expediting = 0; 1216 unsigned long gp_snap; 1217 int i; 1218 int idx; 1219 int oldnice = task_nice(current); 1220 struct rcu_torture *rp; 1221 struct rcu_torture *old_rp; 1222 static DEFINE_TORTURE_RANDOM(rand); 1223 bool stutter_waited; 1224 1225 VERBOSE_TOROUT_STRING("rcu_torture_writer task started"); 1226 if (!can_expedite) 1227 pr_alert("%s" TORTURE_FLAG 1228 " GP expediting controlled from boot/sysfs for %s.\n", 1229 torture_type, cur_ops->name); 1230 if (WARN_ONCE(nsynctypes == 0, 1231 "%s: No update-side primitives.\n", __func__)) { 1232 /* 1233 * No updates primitives, so don't try updating. 1234 * The resulting test won't be testing much, hence the 1235 * above WARN_ONCE(). 1236 */ 1237 rcu_torture_writer_state = RTWS_STOPPING; 1238 torture_kthread_stopping("rcu_torture_writer"); 1239 return 0; 1240 } 1241 1242 do { 1243 rcu_torture_writer_state = RTWS_FIXED_DELAY; 1244 torture_hrtimeout_us(500, 1000, &rand); 1245 rp = rcu_torture_alloc(); 1246 if (rp == NULL) 1247 continue; 1248 rp->rtort_pipe_count = 0; 1249 rcu_torture_writer_state = RTWS_DELAY; 1250 udelay(torture_random(&rand) & 0x3ff); 1251 rcu_torture_writer_state = RTWS_REPLACE; 1252 old_rp = rcu_dereference_check(rcu_torture_current, 1253 current == writer_task); 1254 rp->rtort_mbtest = 1; 1255 rcu_assign_pointer(rcu_torture_current, rp); 1256 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */ 1257 if (old_rp) { 1258 i = old_rp->rtort_pipe_count; 1259 if (i > RCU_TORTURE_PIPE_LEN) 1260 i = RCU_TORTURE_PIPE_LEN; 1261 atomic_inc(&rcu_torture_wcount[i]); 1262 WRITE_ONCE(old_rp->rtort_pipe_count, 1263 old_rp->rtort_pipe_count + 1); 1264 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) { 1265 idx = cur_ops->readlock(); 1266 cookie = cur_ops->get_gp_state(); 1267 WARN_ONCE(rcu_torture_writer_state != RTWS_DEF_FREE && 1268 cur_ops->poll_gp_state(cookie), 1269 "%s: Cookie check 1 failed %s(%d) %lu->%lu\n", 1270 __func__, 1271 rcu_torture_writer_state_getname(), 1272 rcu_torture_writer_state, 1273 cookie, cur_ops->get_gp_state()); 1274 if (cur_ops->get_gp_completed) { 1275 cookie = cur_ops->get_gp_completed(); 1276 WARN_ON_ONCE(!cur_ops->poll_gp_state(cookie)); 1277 } 1278 cur_ops->readunlock(idx); 1279 } 1280 switch (synctype[torture_random(&rand) % nsynctypes]) { 1281 case RTWS_DEF_FREE: 1282 rcu_torture_writer_state = RTWS_DEF_FREE; 1283 cur_ops->deferred_free(old_rp); 1284 break; 1285 case RTWS_EXP_SYNC: 1286 rcu_torture_writer_state = RTWS_EXP_SYNC; 1287 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) 1288 cookie = cur_ops->get_gp_state(); 1289 cur_ops->exp_sync(); 1290 cur_ops->exp_sync(); 1291 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) 1292 WARN_ON_ONCE(!cur_ops->poll_gp_state(cookie)); 1293 rcu_torture_pipe_update(old_rp); 1294 break; 1295 case RTWS_COND_GET: 1296 rcu_torture_writer_state = RTWS_COND_GET; 1297 gp_snap = cur_ops->get_gp_state(); 1298 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); 1299 rcu_torture_writer_state = RTWS_COND_SYNC; 1300 cur_ops->cond_sync(gp_snap); 1301 rcu_torture_pipe_update(old_rp); 1302 break; 1303 case RTWS_COND_GET_EXP: 1304 rcu_torture_writer_state = RTWS_COND_GET_EXP; 1305 gp_snap = cur_ops->get_gp_state_exp(); 1306 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); 1307 rcu_torture_writer_state = RTWS_COND_SYNC_EXP; 1308 cur_ops->cond_sync_exp(gp_snap); 1309 rcu_torture_pipe_update(old_rp); 1310 break; 1311 case RTWS_POLL_GET: 1312 rcu_torture_writer_state = RTWS_POLL_GET; 1313 gp_snap = cur_ops->start_gp_poll(); 1314 rcu_torture_writer_state = RTWS_POLL_WAIT; 1315 while (!cur_ops->poll_gp_state(gp_snap)) 1316 torture_hrtimeout_jiffies(torture_random(&rand) % 16, 1317 &rand); 1318 rcu_torture_pipe_update(old_rp); 1319 break; 1320 case RTWS_POLL_GET_EXP: 1321 rcu_torture_writer_state = RTWS_POLL_GET_EXP; 1322 gp_snap = cur_ops->start_gp_poll_exp(); 1323 rcu_torture_writer_state = RTWS_POLL_WAIT_EXP; 1324 while (!cur_ops->poll_gp_state_exp(gp_snap)) 1325 torture_hrtimeout_jiffies(torture_random(&rand) % 16, 1326 &rand); 1327 rcu_torture_pipe_update(old_rp); 1328 break; 1329 case RTWS_SYNC: 1330 rcu_torture_writer_state = RTWS_SYNC; 1331 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) 1332 cookie = cur_ops->get_gp_state(); 1333 cur_ops->sync(); 1334 cur_ops->sync(); 1335 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) 1336 WARN_ON_ONCE(!cur_ops->poll_gp_state(cookie)); 1337 rcu_torture_pipe_update(old_rp); 1338 break; 1339 default: 1340 WARN_ON_ONCE(1); 1341 break; 1342 } 1343 } 1344 WRITE_ONCE(rcu_torture_current_version, 1345 rcu_torture_current_version + 1); 1346 /* Cycle through nesting levels of rcu_expedite_gp() calls. */ 1347 if (can_expedite && 1348 !(torture_random(&rand) & 0xff & (!!expediting - 1))) { 1349 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited()); 1350 if (expediting >= 0) 1351 rcu_expedite_gp(); 1352 else 1353 rcu_unexpedite_gp(); 1354 if (++expediting > 3) 1355 expediting = -expediting; 1356 } else if (!can_expedite) { /* Disabled during boot, recheck. */ 1357 can_expedite = !rcu_gp_is_expedited() && 1358 !rcu_gp_is_normal(); 1359 } 1360 rcu_torture_writer_state = RTWS_STUTTER; 1361 boot_ended = rcu_inkernel_boot_has_ended(); 1362 stutter_waited = stutter_wait("rcu_torture_writer"); 1363 if (stutter_waited && 1364 !atomic_read(&rcu_fwd_cb_nodelay) && 1365 !cur_ops->slow_gps && 1366 !torture_must_stop() && 1367 boot_ended) 1368 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) 1369 if (list_empty(&rcu_tortures[i].rtort_free) && 1370 rcu_access_pointer(rcu_torture_current) != 1371 &rcu_tortures[i]) { 1372 tracing_off(); 1373 WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count); 1374 rcu_ftrace_dump(DUMP_ALL); 1375 } 1376 if (stutter_waited) 1377 sched_set_normal(current, oldnice); 1378 } while (!torture_must_stop()); 1379 rcu_torture_current = NULL; // Let stats task know that we are done. 1380 /* Reset expediting back to unexpedited. */ 1381 if (expediting > 0) 1382 expediting = -expediting; 1383 while (can_expedite && expediting++ < 0) 1384 rcu_unexpedite_gp(); 1385 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited()); 1386 if (!can_expedite) 1387 pr_alert("%s" TORTURE_FLAG 1388 " Dynamic grace-period expediting was disabled.\n", 1389 torture_type); 1390 rcu_torture_writer_state = RTWS_STOPPING; 1391 torture_kthread_stopping("rcu_torture_writer"); 1392 return 0; 1393 } 1394 1395 /* 1396 * RCU torture fake writer kthread. Repeatedly calls sync, with a random 1397 * delay between calls. 1398 */ 1399 static int 1400 rcu_torture_fakewriter(void *arg) 1401 { 1402 unsigned long gp_snap; 1403 DEFINE_TORTURE_RANDOM(rand); 1404 1405 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started"); 1406 set_user_nice(current, MAX_NICE); 1407 1408 if (WARN_ONCE(nsynctypes == 0, 1409 "%s: No update-side primitives.\n", __func__)) { 1410 /* 1411 * No updates primitives, so don't try updating. 1412 * The resulting test won't be testing much, hence the 1413 * above WARN_ONCE(). 1414 */ 1415 torture_kthread_stopping("rcu_torture_fakewriter"); 1416 return 0; 1417 } 1418 1419 do { 1420 torture_hrtimeout_jiffies(torture_random(&rand) % 10, &rand); 1421 if (cur_ops->cb_barrier != NULL && 1422 torture_random(&rand) % (nfakewriters * 8) == 0) { 1423 cur_ops->cb_barrier(); 1424 } else { 1425 switch (synctype[torture_random(&rand) % nsynctypes]) { 1426 case RTWS_DEF_FREE: 1427 break; 1428 case RTWS_EXP_SYNC: 1429 cur_ops->exp_sync(); 1430 break; 1431 case RTWS_COND_GET: 1432 gp_snap = cur_ops->get_gp_state(); 1433 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); 1434 cur_ops->cond_sync(gp_snap); 1435 break; 1436 case RTWS_COND_GET_EXP: 1437 gp_snap = cur_ops->get_gp_state_exp(); 1438 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); 1439 cur_ops->cond_sync_exp(gp_snap); 1440 break; 1441 case RTWS_POLL_GET: 1442 gp_snap = cur_ops->start_gp_poll(); 1443 while (!cur_ops->poll_gp_state(gp_snap)) { 1444 torture_hrtimeout_jiffies(torture_random(&rand) % 16, 1445 &rand); 1446 } 1447 break; 1448 case RTWS_POLL_GET_EXP: 1449 gp_snap = cur_ops->start_gp_poll_exp(); 1450 while (!cur_ops->poll_gp_state_exp(gp_snap)) { 1451 torture_hrtimeout_jiffies(torture_random(&rand) % 16, 1452 &rand); 1453 } 1454 break; 1455 case RTWS_SYNC: 1456 cur_ops->sync(); 1457 break; 1458 default: 1459 WARN_ON_ONCE(1); 1460 break; 1461 } 1462 } 1463 stutter_wait("rcu_torture_fakewriter"); 1464 } while (!torture_must_stop()); 1465 1466 torture_kthread_stopping("rcu_torture_fakewriter"); 1467 return 0; 1468 } 1469 1470 static void rcu_torture_timer_cb(struct rcu_head *rhp) 1471 { 1472 kfree(rhp); 1473 } 1474 1475 // Set up and carry out testing of RCU's global memory ordering 1476 static void rcu_torture_reader_do_mbchk(long myid, struct rcu_torture *rtp, 1477 struct torture_random_state *trsp) 1478 { 1479 unsigned long loops; 1480 int noc = torture_num_online_cpus(); 1481 int rdrchked; 1482 int rdrchker; 1483 struct rcu_torture_reader_check *rtrcp; // Me. 1484 struct rcu_torture_reader_check *rtrcp_assigner; // Assigned us to do checking. 1485 struct rcu_torture_reader_check *rtrcp_chked; // Reader being checked. 1486 struct rcu_torture_reader_check *rtrcp_chker; // Reader doing checking when not me. 1487 1488 if (myid < 0) 1489 return; // Don't try this from timer handlers. 1490 1491 // Increment my counter. 1492 rtrcp = &rcu_torture_reader_mbchk[myid]; 1493 WRITE_ONCE(rtrcp->rtc_myloops, rtrcp->rtc_myloops + 1); 1494 1495 // Attempt to assign someone else some checking work. 1496 rdrchked = torture_random(trsp) % nrealreaders; 1497 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked]; 1498 rdrchker = torture_random(trsp) % nrealreaders; 1499 rtrcp_chker = &rcu_torture_reader_mbchk[rdrchker]; 1500 if (rdrchked != myid && rdrchked != rdrchker && noc >= rdrchked && noc >= rdrchker && 1501 smp_load_acquire(&rtrcp->rtc_chkrdr) < 0 && // Pairs with smp_store_release below. 1502 !READ_ONCE(rtp->rtort_chkp) && 1503 !smp_load_acquire(&rtrcp_chker->rtc_assigner)) { // Pairs with smp_store_release below. 1504 rtrcp->rtc_chkloops = READ_ONCE(rtrcp_chked->rtc_myloops); 1505 WARN_ON_ONCE(rtrcp->rtc_chkrdr >= 0); 1506 rtrcp->rtc_chkrdr = rdrchked; 1507 WARN_ON_ONCE(rtrcp->rtc_ready); // This gets set after the grace period ends. 1508 if (cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, NULL, rtrcp) || 1509 cmpxchg_relaxed(&rtp->rtort_chkp, NULL, rtrcp)) 1510 (void)cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, rtrcp, NULL); // Back out. 1511 } 1512 1513 // If assigned some completed work, do it! 1514 rtrcp_assigner = READ_ONCE(rtrcp->rtc_assigner); 1515 if (!rtrcp_assigner || !smp_load_acquire(&rtrcp_assigner->rtc_ready)) 1516 return; // No work or work not yet ready. 1517 rdrchked = rtrcp_assigner->rtc_chkrdr; 1518 if (WARN_ON_ONCE(rdrchked < 0)) 1519 return; 1520 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked]; 1521 loops = READ_ONCE(rtrcp_chked->rtc_myloops); 1522 atomic_inc(&n_rcu_torture_mbchk_tries); 1523 if (ULONG_CMP_LT(loops, rtrcp_assigner->rtc_chkloops)) 1524 atomic_inc(&n_rcu_torture_mbchk_fail); 1525 rtrcp_assigner->rtc_chkloops = loops + ULONG_MAX / 2; 1526 rtrcp_assigner->rtc_ready = 0; 1527 smp_store_release(&rtrcp->rtc_assigner, NULL); // Someone else can assign us work. 1528 smp_store_release(&rtrcp_assigner->rtc_chkrdr, -1); // Assigner can again assign. 1529 } 1530 1531 /* 1532 * Do one extension of an RCU read-side critical section using the 1533 * current reader state in readstate (set to zero for initial entry 1534 * to extended critical section), set the new state as specified by 1535 * newstate (set to zero for final exit from extended critical section), 1536 * and random-number-generator state in trsp. If this is neither the 1537 * beginning or end of the critical section and if there was actually a 1538 * change, do a ->read_delay(). 1539 */ 1540 static void rcutorture_one_extend(int *readstate, int newstate, 1541 struct torture_random_state *trsp, 1542 struct rt_read_seg *rtrsp) 1543 { 1544 unsigned long flags; 1545 int idxnew1 = -1; 1546 int idxnew2 = -1; 1547 int idxold1 = *readstate; 1548 int idxold2 = idxold1; 1549 int statesnew = ~*readstate & newstate; 1550 int statesold = *readstate & ~newstate; 1551 1552 WARN_ON_ONCE(idxold2 < 0); 1553 WARN_ON_ONCE((idxold2 >> RCUTORTURE_RDR_SHIFT_2) > 1); 1554 rtrsp->rt_readstate = newstate; 1555 1556 /* First, put new protection in place to avoid critical-section gap. */ 1557 if (statesnew & RCUTORTURE_RDR_BH) 1558 local_bh_disable(); 1559 if (statesnew & RCUTORTURE_RDR_RBH) 1560 rcu_read_lock_bh(); 1561 if (statesnew & RCUTORTURE_RDR_IRQ) 1562 local_irq_disable(); 1563 if (statesnew & RCUTORTURE_RDR_PREEMPT) 1564 preempt_disable(); 1565 if (statesnew & RCUTORTURE_RDR_SCHED) 1566 rcu_read_lock_sched(); 1567 if (statesnew & RCUTORTURE_RDR_RCU_1) 1568 idxnew1 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_1; 1569 if (statesnew & RCUTORTURE_RDR_RCU_2) 1570 idxnew2 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_2; 1571 1572 /* 1573 * Next, remove old protection, in decreasing order of strength 1574 * to avoid unlock paths that aren't safe in the stronger 1575 * context. Namely: BH can not be enabled with disabled interrupts. 1576 * Additionally PREEMPT_RT requires that BH is enabled in preemptible 1577 * context. 1578 */ 1579 if (statesold & RCUTORTURE_RDR_IRQ) 1580 local_irq_enable(); 1581 if (statesold & RCUTORTURE_RDR_PREEMPT) 1582 preempt_enable(); 1583 if (statesold & RCUTORTURE_RDR_SCHED) 1584 rcu_read_unlock_sched(); 1585 if (statesold & RCUTORTURE_RDR_BH) 1586 local_bh_enable(); 1587 if (statesold & RCUTORTURE_RDR_RBH) 1588 rcu_read_unlock_bh(); 1589 if (statesold & RCUTORTURE_RDR_RCU_2) { 1590 cur_ops->readunlock((idxold2 >> RCUTORTURE_RDR_SHIFT_2) & 0x1); 1591 WARN_ON_ONCE(idxnew2 != -1); 1592 idxold2 = 0; 1593 } 1594 if (statesold & RCUTORTURE_RDR_RCU_1) { 1595 bool lockit; 1596 1597 lockit = !cur_ops->no_pi_lock && !statesnew && !(torture_random(trsp) & 0xffff); 1598 if (lockit) 1599 raw_spin_lock_irqsave(¤t->pi_lock, flags); 1600 cur_ops->readunlock((idxold1 >> RCUTORTURE_RDR_SHIFT_1) & 0x1); 1601 WARN_ON_ONCE(idxnew1 != -1); 1602 idxold1 = 0; 1603 if (lockit) 1604 raw_spin_unlock_irqrestore(¤t->pi_lock, flags); 1605 } 1606 1607 /* Delay if neither beginning nor end and there was a change. */ 1608 if ((statesnew || statesold) && *readstate && newstate) 1609 cur_ops->read_delay(trsp, rtrsp); 1610 1611 /* Update the reader state. */ 1612 if (idxnew1 == -1) 1613 idxnew1 = idxold1 & RCUTORTURE_RDR_MASK_1; 1614 WARN_ON_ONCE(idxnew1 < 0); 1615 if (WARN_ON_ONCE((idxnew1 >> RCUTORTURE_RDR_SHIFT_1) > 1)) 1616 pr_info("Unexpected idxnew1 value of %#x\n", idxnew1); 1617 if (idxnew2 == -1) 1618 idxnew2 = idxold2 & RCUTORTURE_RDR_MASK_2; 1619 WARN_ON_ONCE(idxnew2 < 0); 1620 WARN_ON_ONCE((idxnew2 >> RCUTORTURE_RDR_SHIFT_2) > 1); 1621 *readstate = idxnew1 | idxnew2 | newstate; 1622 WARN_ON_ONCE(*readstate < 0); 1623 if (WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT_2) > 1)) 1624 pr_info("Unexpected idxnew2 value of %#x\n", idxnew2); 1625 } 1626 1627 /* Return the biggest extendables mask given current RCU and boot parameters. */ 1628 static int rcutorture_extend_mask_max(void) 1629 { 1630 int mask; 1631 1632 WARN_ON_ONCE(extendables & ~RCUTORTURE_MAX_EXTEND); 1633 mask = extendables & RCUTORTURE_MAX_EXTEND & cur_ops->extendables; 1634 mask = mask | RCUTORTURE_RDR_RCU_1 | RCUTORTURE_RDR_RCU_2; 1635 return mask; 1636 } 1637 1638 /* Return a random protection state mask, but with at least one bit set. */ 1639 static int 1640 rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp) 1641 { 1642 int mask = rcutorture_extend_mask_max(); 1643 unsigned long randmask1 = torture_random(trsp) >> 8; 1644 unsigned long randmask2 = randmask1 >> 3; 1645 unsigned long preempts = RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED; 1646 unsigned long preempts_irq = preempts | RCUTORTURE_RDR_IRQ; 1647 unsigned long bhs = RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH; 1648 1649 WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT_1); 1650 /* Mostly only one bit (need preemption!), sometimes lots of bits. */ 1651 if (!(randmask1 & 0x7)) 1652 mask = mask & randmask2; 1653 else 1654 mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS)); 1655 1656 // Can't have nested RCU reader without outer RCU reader. 1657 if (!(mask & RCUTORTURE_RDR_RCU_1) && (mask & RCUTORTURE_RDR_RCU_2)) { 1658 if (oldmask & RCUTORTURE_RDR_RCU_1) 1659 mask &= ~RCUTORTURE_RDR_RCU_2; 1660 else 1661 mask |= RCUTORTURE_RDR_RCU_1; 1662 } 1663 1664 /* 1665 * Can't enable bh w/irq disabled. 1666 */ 1667 if (mask & RCUTORTURE_RDR_IRQ) 1668 mask |= oldmask & bhs; 1669 1670 /* 1671 * Ideally these sequences would be detected in debug builds 1672 * (regardless of RT), but until then don't stop testing 1673 * them on non-RT. 1674 */ 1675 if (IS_ENABLED(CONFIG_PREEMPT_RT)) { 1676 /* Can't modify BH in atomic context */ 1677 if (oldmask & preempts_irq) 1678 mask &= ~bhs; 1679 if ((oldmask | mask) & preempts_irq) 1680 mask |= oldmask & bhs; 1681 } 1682 1683 return mask ?: RCUTORTURE_RDR_RCU_1; 1684 } 1685 1686 /* 1687 * Do a randomly selected number of extensions of an existing RCU read-side 1688 * critical section. 1689 */ 1690 static struct rt_read_seg * 1691 rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp, 1692 struct rt_read_seg *rtrsp) 1693 { 1694 int i; 1695 int j; 1696 int mask = rcutorture_extend_mask_max(); 1697 1698 WARN_ON_ONCE(!*readstate); /* -Existing- RCU read-side critsect! */ 1699 if (!((mask - 1) & mask)) 1700 return rtrsp; /* Current RCU reader not extendable. */ 1701 /* Bias towards larger numbers of loops. */ 1702 i = (torture_random(trsp) >> 3); 1703 i = ((i | (i >> 3)) & RCUTORTURE_RDR_MAX_LOOPS) + 1; 1704 for (j = 0; j < i; j++) { 1705 mask = rcutorture_extend_mask(*readstate, trsp); 1706 rcutorture_one_extend(readstate, mask, trsp, &rtrsp[j]); 1707 } 1708 return &rtrsp[j]; 1709 } 1710 1711 /* 1712 * Do one read-side critical section, returning false if there was 1713 * no data to read. Can be invoked both from process context and 1714 * from a timer handler. 1715 */ 1716 static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid) 1717 { 1718 unsigned long cookie; 1719 int i; 1720 unsigned long started; 1721 unsigned long completed; 1722 int newstate; 1723 struct rcu_torture *p; 1724 int pipe_count; 1725 int readstate = 0; 1726 struct rt_read_seg rtseg[RCUTORTURE_RDR_MAX_SEGS] = { { 0 } }; 1727 struct rt_read_seg *rtrsp = &rtseg[0]; 1728 struct rt_read_seg *rtrsp1; 1729 unsigned long long ts; 1730 1731 WARN_ON_ONCE(!rcu_is_watching()); 1732 newstate = rcutorture_extend_mask(readstate, trsp); 1733 rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++); 1734 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) 1735 cookie = cur_ops->get_gp_state(); 1736 started = cur_ops->get_gp_seq(); 1737 ts = rcu_trace_clock_local(); 1738 p = rcu_dereference_check(rcu_torture_current, 1739 !cur_ops->readlock_held || cur_ops->readlock_held()); 1740 if (p == NULL) { 1741 /* Wait for rcu_torture_writer to get underway */ 1742 rcutorture_one_extend(&readstate, 0, trsp, rtrsp); 1743 return false; 1744 } 1745 if (p->rtort_mbtest == 0) 1746 atomic_inc(&n_rcu_torture_mberror); 1747 rcu_torture_reader_do_mbchk(myid, p, trsp); 1748 rtrsp = rcutorture_loop_extend(&readstate, trsp, rtrsp); 1749 preempt_disable(); 1750 pipe_count = READ_ONCE(p->rtort_pipe_count); 1751 if (pipe_count > RCU_TORTURE_PIPE_LEN) { 1752 /* Should not happen, but... */ 1753 pipe_count = RCU_TORTURE_PIPE_LEN; 1754 } 1755 completed = cur_ops->get_gp_seq(); 1756 if (pipe_count > 1) { 1757 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, 1758 ts, started, completed); 1759 rcu_ftrace_dump(DUMP_ALL); 1760 } 1761 __this_cpu_inc(rcu_torture_count[pipe_count]); 1762 completed = rcutorture_seq_diff(completed, started); 1763 if (completed > RCU_TORTURE_PIPE_LEN) { 1764 /* Should not happen, but... */ 1765 completed = RCU_TORTURE_PIPE_LEN; 1766 } 1767 __this_cpu_inc(rcu_torture_batch[completed]); 1768 preempt_enable(); 1769 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) 1770 WARN_ONCE(cur_ops->poll_gp_state(cookie), 1771 "%s: Cookie check 2 failed %s(%d) %lu->%lu\n", 1772 __func__, 1773 rcu_torture_writer_state_getname(), 1774 rcu_torture_writer_state, 1775 cookie, cur_ops->get_gp_state()); 1776 rcutorture_one_extend(&readstate, 0, trsp, rtrsp); 1777 WARN_ON_ONCE(readstate); 1778 // This next splat is expected behavior if leakpointer, especially 1779 // for CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels. 1780 WARN_ON_ONCE(leakpointer && READ_ONCE(p->rtort_pipe_count) > 1); 1781 1782 /* If error or close call, record the sequence of reader protections. */ 1783 if ((pipe_count > 1 || completed > 1) && !xchg(&err_segs_recorded, 1)) { 1784 i = 0; 1785 for (rtrsp1 = &rtseg[0]; rtrsp1 < rtrsp; rtrsp1++) 1786 err_segs[i++] = *rtrsp1; 1787 rt_read_nsegs = i; 1788 } 1789 1790 return true; 1791 } 1792 1793 static DEFINE_TORTURE_RANDOM_PERCPU(rcu_torture_timer_rand); 1794 1795 /* 1796 * RCU torture reader from timer handler. Dereferences rcu_torture_current, 1797 * incrementing the corresponding element of the pipeline array. The 1798 * counter in the element should never be greater than 1, otherwise, the 1799 * RCU implementation is broken. 1800 */ 1801 static void rcu_torture_timer(struct timer_list *unused) 1802 { 1803 atomic_long_inc(&n_rcu_torture_timers); 1804 (void)rcu_torture_one_read(this_cpu_ptr(&rcu_torture_timer_rand), -1); 1805 1806 /* Test call_rcu() invocation from interrupt handler. */ 1807 if (cur_ops->call) { 1808 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT); 1809 1810 if (rhp) 1811 cur_ops->call(rhp, rcu_torture_timer_cb); 1812 } 1813 } 1814 1815 /* 1816 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current, 1817 * incrementing the corresponding element of the pipeline array. The 1818 * counter in the element should never be greater than 1, otherwise, the 1819 * RCU implementation is broken. 1820 */ 1821 static int 1822 rcu_torture_reader(void *arg) 1823 { 1824 unsigned long lastsleep = jiffies; 1825 long myid = (long)arg; 1826 int mynumonline = myid; 1827 DEFINE_TORTURE_RANDOM(rand); 1828 struct timer_list t; 1829 1830 VERBOSE_TOROUT_STRING("rcu_torture_reader task started"); 1831 set_user_nice(current, MAX_NICE); 1832 if (irqreader && cur_ops->irq_capable) 1833 timer_setup_on_stack(&t, rcu_torture_timer, 0); 1834 tick_dep_set_task(current, TICK_DEP_BIT_RCU); 1835 do { 1836 if (irqreader && cur_ops->irq_capable) { 1837 if (!timer_pending(&t)) 1838 mod_timer(&t, jiffies + 1); 1839 } 1840 if (!rcu_torture_one_read(&rand, myid) && !torture_must_stop()) 1841 schedule_timeout_interruptible(HZ); 1842 if (time_after(jiffies, lastsleep) && !torture_must_stop()) { 1843 torture_hrtimeout_us(500, 1000, &rand); 1844 lastsleep = jiffies + 10; 1845 } 1846 while (torture_num_online_cpus() < mynumonline && !torture_must_stop()) 1847 schedule_timeout_interruptible(HZ / 5); 1848 stutter_wait("rcu_torture_reader"); 1849 } while (!torture_must_stop()); 1850 if (irqreader && cur_ops->irq_capable) { 1851 del_timer_sync(&t); 1852 destroy_timer_on_stack(&t); 1853 } 1854 tick_dep_clear_task(current, TICK_DEP_BIT_RCU); 1855 torture_kthread_stopping("rcu_torture_reader"); 1856 return 0; 1857 } 1858 1859 /* 1860 * Randomly Toggle CPUs' callback-offload state. This uses hrtimers to 1861 * increase race probabilities and fuzzes the interval between toggling. 1862 */ 1863 static int rcu_nocb_toggle(void *arg) 1864 { 1865 int cpu; 1866 int maxcpu = -1; 1867 int oldnice = task_nice(current); 1868 long r; 1869 DEFINE_TORTURE_RANDOM(rand); 1870 ktime_t toggle_delay; 1871 unsigned long toggle_fuzz; 1872 ktime_t toggle_interval = ms_to_ktime(nocbs_toggle); 1873 1874 VERBOSE_TOROUT_STRING("rcu_nocb_toggle task started"); 1875 while (!rcu_inkernel_boot_has_ended()) 1876 schedule_timeout_interruptible(HZ / 10); 1877 for_each_online_cpu(cpu) 1878 maxcpu = cpu; 1879 WARN_ON(maxcpu < 0); 1880 if (toggle_interval > ULONG_MAX) 1881 toggle_fuzz = ULONG_MAX >> 3; 1882 else 1883 toggle_fuzz = toggle_interval >> 3; 1884 if (toggle_fuzz <= 0) 1885 toggle_fuzz = NSEC_PER_USEC; 1886 do { 1887 r = torture_random(&rand); 1888 cpu = (r >> 4) % (maxcpu + 1); 1889 if (r & 0x1) { 1890 rcu_nocb_cpu_offload(cpu); 1891 atomic_long_inc(&n_nocb_offload); 1892 } else { 1893 rcu_nocb_cpu_deoffload(cpu); 1894 atomic_long_inc(&n_nocb_deoffload); 1895 } 1896 toggle_delay = torture_random(&rand) % toggle_fuzz + toggle_interval; 1897 set_current_state(TASK_INTERRUPTIBLE); 1898 schedule_hrtimeout(&toggle_delay, HRTIMER_MODE_REL); 1899 if (stutter_wait("rcu_nocb_toggle")) 1900 sched_set_normal(current, oldnice); 1901 } while (!torture_must_stop()); 1902 torture_kthread_stopping("rcu_nocb_toggle"); 1903 return 0; 1904 } 1905 1906 /* 1907 * Print torture statistics. Caller must ensure that there is only 1908 * one call to this function at a given time!!! This is normally 1909 * accomplished by relying on the module system to only have one copy 1910 * of the module loaded, and then by giving the rcu_torture_stats 1911 * kthread full control (or the init/cleanup functions when rcu_torture_stats 1912 * thread is not running). 1913 */ 1914 static void 1915 rcu_torture_stats_print(void) 1916 { 1917 int cpu; 1918 int i; 1919 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; 1920 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; 1921 struct rcu_torture *rtcp; 1922 static unsigned long rtcv_snap = ULONG_MAX; 1923 static bool splatted; 1924 struct task_struct *wtp; 1925 1926 for_each_possible_cpu(cpu) { 1927 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 1928 pipesummary[i] += READ_ONCE(per_cpu(rcu_torture_count, cpu)[i]); 1929 batchsummary[i] += READ_ONCE(per_cpu(rcu_torture_batch, cpu)[i]); 1930 } 1931 } 1932 for (i = RCU_TORTURE_PIPE_LEN; i >= 0; i--) { 1933 if (pipesummary[i] != 0) 1934 break; 1935 } 1936 1937 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1938 rtcp = rcu_access_pointer(rcu_torture_current); 1939 pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ", 1940 rtcp, 1941 rtcp && !rcu_stall_is_suppressed_at_boot() ? "ver" : "VER", 1942 rcu_torture_current_version, 1943 list_empty(&rcu_torture_freelist), 1944 atomic_read(&n_rcu_torture_alloc), 1945 atomic_read(&n_rcu_torture_alloc_fail), 1946 atomic_read(&n_rcu_torture_free)); 1947 pr_cont("rtmbe: %d rtmbkf: %d/%d rtbe: %ld rtbke: %ld rtbre: %ld ", 1948 atomic_read(&n_rcu_torture_mberror), 1949 atomic_read(&n_rcu_torture_mbchk_fail), atomic_read(&n_rcu_torture_mbchk_tries), 1950 n_rcu_torture_barrier_error, 1951 n_rcu_torture_boost_ktrerror, 1952 n_rcu_torture_boost_rterror); 1953 pr_cont("rtbf: %ld rtb: %ld nt: %ld ", 1954 n_rcu_torture_boost_failure, 1955 n_rcu_torture_boosts, 1956 atomic_long_read(&n_rcu_torture_timers)); 1957 torture_onoff_stats(); 1958 pr_cont("barrier: %ld/%ld:%ld ", 1959 data_race(n_barrier_successes), 1960 data_race(n_barrier_attempts), 1961 data_race(n_rcu_torture_barrier_error)); 1962 pr_cont("read-exits: %ld ", data_race(n_read_exits)); // Statistic. 1963 pr_cont("nocb-toggles: %ld:%ld\n", 1964 atomic_long_read(&n_nocb_offload), atomic_long_read(&n_nocb_deoffload)); 1965 1966 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1967 if (atomic_read(&n_rcu_torture_mberror) || 1968 atomic_read(&n_rcu_torture_mbchk_fail) || 1969 n_rcu_torture_barrier_error || n_rcu_torture_boost_ktrerror || 1970 n_rcu_torture_boost_rterror || n_rcu_torture_boost_failure || 1971 i > 1) { 1972 pr_cont("%s", "!!! "); 1973 atomic_inc(&n_rcu_torture_error); 1974 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mberror)); 1975 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mbchk_fail)); 1976 WARN_ON_ONCE(n_rcu_torture_barrier_error); // rcu_barrier() 1977 WARN_ON_ONCE(n_rcu_torture_boost_ktrerror); // no boost kthread 1978 WARN_ON_ONCE(n_rcu_torture_boost_rterror); // can't set RT prio 1979 WARN_ON_ONCE(n_rcu_torture_boost_failure); // boost failed (TIMER_SOFTIRQ RT prio?) 1980 WARN_ON_ONCE(i > 1); // Too-short grace period 1981 } 1982 pr_cont("Reader Pipe: "); 1983 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 1984 pr_cont(" %ld", pipesummary[i]); 1985 pr_cont("\n"); 1986 1987 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1988 pr_cont("Reader Batch: "); 1989 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 1990 pr_cont(" %ld", batchsummary[i]); 1991 pr_cont("\n"); 1992 1993 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 1994 pr_cont("Free-Block Circulation: "); 1995 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 1996 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i])); 1997 } 1998 pr_cont("\n"); 1999 2000 if (cur_ops->stats) 2001 cur_ops->stats(); 2002 if (rtcv_snap == rcu_torture_current_version && 2003 rcu_access_pointer(rcu_torture_current) && 2004 !rcu_stall_is_suppressed()) { 2005 int __maybe_unused flags = 0; 2006 unsigned long __maybe_unused gp_seq = 0; 2007 2008 rcutorture_get_gp_data(cur_ops->ttype, 2009 &flags, &gp_seq); 2010 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, 2011 &flags, &gp_seq); 2012 wtp = READ_ONCE(writer_task); 2013 pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#x cpu %d\n", 2014 rcu_torture_writer_state_getname(), 2015 rcu_torture_writer_state, gp_seq, flags, 2016 wtp == NULL ? ~0U : wtp->__state, 2017 wtp == NULL ? -1 : (int)task_cpu(wtp)); 2018 if (!splatted && wtp) { 2019 sched_show_task(wtp); 2020 splatted = true; 2021 } 2022 if (cur_ops->gp_kthread_dbg) 2023 cur_ops->gp_kthread_dbg(); 2024 rcu_ftrace_dump(DUMP_ALL); 2025 } 2026 rtcv_snap = rcu_torture_current_version; 2027 } 2028 2029 /* 2030 * Periodically prints torture statistics, if periodic statistics printing 2031 * was specified via the stat_interval module parameter. 2032 */ 2033 static int 2034 rcu_torture_stats(void *arg) 2035 { 2036 VERBOSE_TOROUT_STRING("rcu_torture_stats task started"); 2037 do { 2038 schedule_timeout_interruptible(stat_interval * HZ); 2039 rcu_torture_stats_print(); 2040 torture_shutdown_absorb("rcu_torture_stats"); 2041 } while (!torture_must_stop()); 2042 torture_kthread_stopping("rcu_torture_stats"); 2043 return 0; 2044 } 2045 2046 /* Test mem_dump_obj() and friends. */ 2047 static void rcu_torture_mem_dump_obj(void) 2048 { 2049 struct rcu_head *rhp; 2050 struct kmem_cache *kcp; 2051 static int z; 2052 2053 kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL); 2054 if (WARN_ON_ONCE(!kcp)) 2055 return; 2056 rhp = kmem_cache_alloc(kcp, GFP_KERNEL); 2057 if (WARN_ON_ONCE(!rhp)) { 2058 kmem_cache_destroy(kcp); 2059 return; 2060 } 2061 pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z); 2062 pr_alert("mem_dump_obj(ZERO_SIZE_PTR):"); 2063 mem_dump_obj(ZERO_SIZE_PTR); 2064 pr_alert("mem_dump_obj(NULL):"); 2065 mem_dump_obj(NULL); 2066 pr_alert("mem_dump_obj(%px):", &rhp); 2067 mem_dump_obj(&rhp); 2068 pr_alert("mem_dump_obj(%px):", rhp); 2069 mem_dump_obj(rhp); 2070 pr_alert("mem_dump_obj(%px):", &rhp->func); 2071 mem_dump_obj(&rhp->func); 2072 pr_alert("mem_dump_obj(%px):", &z); 2073 mem_dump_obj(&z); 2074 kmem_cache_free(kcp, rhp); 2075 kmem_cache_destroy(kcp); 2076 rhp = kmalloc(sizeof(*rhp), GFP_KERNEL); 2077 if (WARN_ON_ONCE(!rhp)) 2078 return; 2079 pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp); 2080 pr_alert("mem_dump_obj(kmalloc %px):", rhp); 2081 mem_dump_obj(rhp); 2082 pr_alert("mem_dump_obj(kmalloc %px):", &rhp->func); 2083 mem_dump_obj(&rhp->func); 2084 kfree(rhp); 2085 rhp = vmalloc(4096); 2086 if (WARN_ON_ONCE(!rhp)) 2087 return; 2088 pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp); 2089 pr_alert("mem_dump_obj(vmalloc %px):", rhp); 2090 mem_dump_obj(rhp); 2091 pr_alert("mem_dump_obj(vmalloc %px):", &rhp->func); 2092 mem_dump_obj(&rhp->func); 2093 vfree(rhp); 2094 } 2095 2096 static void 2097 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag) 2098 { 2099 pr_alert("%s" TORTURE_FLAG 2100 "--- %s: nreaders=%d nfakewriters=%d " 2101 "stat_interval=%d verbose=%d test_no_idle_hz=%d " 2102 "shuffle_interval=%d stutter=%d irqreader=%d " 2103 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d " 2104 "test_boost=%d/%d test_boost_interval=%d " 2105 "test_boost_duration=%d shutdown_secs=%d " 2106 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d " 2107 "stall_cpu_block=%d " 2108 "n_barrier_cbs=%d " 2109 "onoff_interval=%d onoff_holdoff=%d " 2110 "read_exit_delay=%d read_exit_burst=%d " 2111 "nocbs_nthreads=%d nocbs_toggle=%d\n", 2112 torture_type, tag, nrealreaders, nfakewriters, 2113 stat_interval, verbose, test_no_idle_hz, shuffle_interval, 2114 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter, 2115 test_boost, cur_ops->can_boost, 2116 test_boost_interval, test_boost_duration, shutdown_secs, 2117 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff, 2118 stall_cpu_block, 2119 n_barrier_cbs, 2120 onoff_interval, onoff_holdoff, 2121 read_exit_delay, read_exit_burst, 2122 nocbs_nthreads, nocbs_toggle); 2123 } 2124 2125 static int rcutorture_booster_cleanup(unsigned int cpu) 2126 { 2127 struct task_struct *t; 2128 2129 if (boost_tasks[cpu] == NULL) 2130 return 0; 2131 mutex_lock(&boost_mutex); 2132 t = boost_tasks[cpu]; 2133 boost_tasks[cpu] = NULL; 2134 rcu_torture_enable_rt_throttle(); 2135 mutex_unlock(&boost_mutex); 2136 2137 /* This must be outside of the mutex, otherwise deadlock! */ 2138 torture_stop_kthread(rcu_torture_boost, t); 2139 return 0; 2140 } 2141 2142 static int rcutorture_booster_init(unsigned int cpu) 2143 { 2144 int retval; 2145 2146 if (boost_tasks[cpu] != NULL) 2147 return 0; /* Already created, nothing more to do. */ 2148 2149 // Testing RCU priority boosting requires rcutorture do 2150 // some serious abuse. Counter this by running ksoftirqd 2151 // at higher priority. 2152 if (IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)) { 2153 struct sched_param sp; 2154 struct task_struct *t; 2155 2156 t = per_cpu(ksoftirqd, cpu); 2157 WARN_ON_ONCE(!t); 2158 sp.sched_priority = 2; 2159 sched_setscheduler_nocheck(t, SCHED_FIFO, &sp); 2160 } 2161 2162 /* Don't allow time recalculation while creating a new task. */ 2163 mutex_lock(&boost_mutex); 2164 rcu_torture_disable_rt_throttle(); 2165 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task"); 2166 boost_tasks[cpu] = kthread_run_on_cpu(rcu_torture_boost, NULL, 2167 cpu, "rcu_torture_boost_%u"); 2168 if (IS_ERR(boost_tasks[cpu])) { 2169 retval = PTR_ERR(boost_tasks[cpu]); 2170 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed"); 2171 n_rcu_torture_boost_ktrerror++; 2172 boost_tasks[cpu] = NULL; 2173 mutex_unlock(&boost_mutex); 2174 return retval; 2175 } 2176 mutex_unlock(&boost_mutex); 2177 return 0; 2178 } 2179 2180 /* 2181 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then 2182 * induces a CPU stall for the time specified by stall_cpu. 2183 */ 2184 static int rcu_torture_stall(void *args) 2185 { 2186 int idx; 2187 unsigned long stop_at; 2188 2189 VERBOSE_TOROUT_STRING("rcu_torture_stall task started"); 2190 if (stall_cpu_holdoff > 0) { 2191 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff"); 2192 schedule_timeout_interruptible(stall_cpu_holdoff * HZ); 2193 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff"); 2194 } 2195 if (!kthread_should_stop() && stall_gp_kthread > 0) { 2196 VERBOSE_TOROUT_STRING("rcu_torture_stall begin GP stall"); 2197 rcu_gp_set_torture_wait(stall_gp_kthread * HZ); 2198 for (idx = 0; idx < stall_gp_kthread + 2; idx++) { 2199 if (kthread_should_stop()) 2200 break; 2201 schedule_timeout_uninterruptible(HZ); 2202 } 2203 } 2204 if (!kthread_should_stop() && stall_cpu > 0) { 2205 VERBOSE_TOROUT_STRING("rcu_torture_stall begin CPU stall"); 2206 stop_at = ktime_get_seconds() + stall_cpu; 2207 /* RCU CPU stall is expected behavior in following code. */ 2208 idx = cur_ops->readlock(); 2209 if (stall_cpu_irqsoff) 2210 local_irq_disable(); 2211 else if (!stall_cpu_block) 2212 preempt_disable(); 2213 pr_alert("%s start on CPU %d.\n", 2214 __func__, raw_smp_processor_id()); 2215 while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(), 2216 stop_at)) 2217 if (stall_cpu_block) { 2218 #ifdef CONFIG_PREEMPTION 2219 preempt_schedule(); 2220 #else 2221 schedule_timeout_uninterruptible(HZ); 2222 #endif 2223 } else if (stall_no_softlockup) { 2224 touch_softlockup_watchdog(); 2225 } 2226 if (stall_cpu_irqsoff) 2227 local_irq_enable(); 2228 else if (!stall_cpu_block) 2229 preempt_enable(); 2230 cur_ops->readunlock(idx); 2231 } 2232 pr_alert("%s end.\n", __func__); 2233 torture_shutdown_absorb("rcu_torture_stall"); 2234 while (!kthread_should_stop()) 2235 schedule_timeout_interruptible(10 * HZ); 2236 return 0; 2237 } 2238 2239 /* Spawn CPU-stall kthread, if stall_cpu specified. */ 2240 static int __init rcu_torture_stall_init(void) 2241 { 2242 if (stall_cpu <= 0 && stall_gp_kthread <= 0) 2243 return 0; 2244 return torture_create_kthread(rcu_torture_stall, NULL, stall_task); 2245 } 2246 2247 /* State structure for forward-progress self-propagating RCU callback. */ 2248 struct fwd_cb_state { 2249 struct rcu_head rh; 2250 int stop; 2251 }; 2252 2253 /* 2254 * Forward-progress self-propagating RCU callback function. Because 2255 * callbacks run from softirq, this function is an implicit RCU read-side 2256 * critical section. 2257 */ 2258 static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp) 2259 { 2260 struct fwd_cb_state *fcsp = container_of(rhp, struct fwd_cb_state, rh); 2261 2262 if (READ_ONCE(fcsp->stop)) { 2263 WRITE_ONCE(fcsp->stop, 2); 2264 return; 2265 } 2266 cur_ops->call(&fcsp->rh, rcu_torture_fwd_prog_cb); 2267 } 2268 2269 /* State for continuous-flood RCU callbacks. */ 2270 struct rcu_fwd_cb { 2271 struct rcu_head rh; 2272 struct rcu_fwd_cb *rfc_next; 2273 struct rcu_fwd *rfc_rfp; 2274 int rfc_gps; 2275 }; 2276 2277 #define MAX_FWD_CB_JIFFIES (8 * HZ) /* Maximum CB test duration. */ 2278 #define MIN_FWD_CB_LAUNDERS 3 /* This many CB invocations to count. */ 2279 #define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */ 2280 #define FWD_CBS_HIST_DIV 10 /* Histogram buckets/second. */ 2281 #define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV)) 2282 2283 struct rcu_launder_hist { 2284 long n_launders; 2285 unsigned long launder_gp_seq; 2286 }; 2287 2288 struct rcu_fwd { 2289 spinlock_t rcu_fwd_lock; 2290 struct rcu_fwd_cb *rcu_fwd_cb_head; 2291 struct rcu_fwd_cb **rcu_fwd_cb_tail; 2292 long n_launders_cb; 2293 unsigned long rcu_fwd_startat; 2294 struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST]; 2295 unsigned long rcu_launder_gp_seq_start; 2296 int rcu_fwd_id; 2297 }; 2298 2299 static DEFINE_MUTEX(rcu_fwd_mutex); 2300 static struct rcu_fwd *rcu_fwds; 2301 static unsigned long rcu_fwd_seq; 2302 static atomic_long_t rcu_fwd_max_cbs; 2303 static bool rcu_fwd_emergency_stop; 2304 2305 static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp) 2306 { 2307 unsigned long gps; 2308 unsigned long gps_old; 2309 int i; 2310 int j; 2311 2312 for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--) 2313 if (rfp->n_launders_hist[i].n_launders > 0) 2314 break; 2315 pr_alert("%s: Callback-invocation histogram %d (duration %lu jiffies):", 2316 __func__, rfp->rcu_fwd_id, jiffies - rfp->rcu_fwd_startat); 2317 gps_old = rfp->rcu_launder_gp_seq_start; 2318 for (j = 0; j <= i; j++) { 2319 gps = rfp->n_launders_hist[j].launder_gp_seq; 2320 pr_cont(" %ds/%d: %ld:%ld", 2321 j + 1, FWD_CBS_HIST_DIV, 2322 rfp->n_launders_hist[j].n_launders, 2323 rcutorture_seq_diff(gps, gps_old)); 2324 gps_old = gps; 2325 } 2326 pr_cont("\n"); 2327 } 2328 2329 /* Callback function for continuous-flood RCU callbacks. */ 2330 static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp) 2331 { 2332 unsigned long flags; 2333 int i; 2334 struct rcu_fwd_cb *rfcp = container_of(rhp, struct rcu_fwd_cb, rh); 2335 struct rcu_fwd_cb **rfcpp; 2336 struct rcu_fwd *rfp = rfcp->rfc_rfp; 2337 2338 rfcp->rfc_next = NULL; 2339 rfcp->rfc_gps++; 2340 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags); 2341 rfcpp = rfp->rcu_fwd_cb_tail; 2342 rfp->rcu_fwd_cb_tail = &rfcp->rfc_next; 2343 WRITE_ONCE(*rfcpp, rfcp); 2344 WRITE_ONCE(rfp->n_launders_cb, rfp->n_launders_cb + 1); 2345 i = ((jiffies - rfp->rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV)); 2346 if (i >= ARRAY_SIZE(rfp->n_launders_hist)) 2347 i = ARRAY_SIZE(rfp->n_launders_hist) - 1; 2348 rfp->n_launders_hist[i].n_launders++; 2349 rfp->n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq(); 2350 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 2351 } 2352 2353 // Give the scheduler a chance, even on nohz_full CPUs. 2354 static void rcu_torture_fwd_prog_cond_resched(unsigned long iter) 2355 { 2356 if (IS_ENABLED(CONFIG_PREEMPTION) && IS_ENABLED(CONFIG_NO_HZ_FULL)) { 2357 // Real call_rcu() floods hit userspace, so emulate that. 2358 if (need_resched() || (iter & 0xfff)) 2359 schedule(); 2360 return; 2361 } 2362 // No userspace emulation: CB invocation throttles call_rcu() 2363 cond_resched(); 2364 } 2365 2366 /* 2367 * Free all callbacks on the rcu_fwd_cb_head list, either because the 2368 * test is over or because we hit an OOM event. 2369 */ 2370 static unsigned long rcu_torture_fwd_prog_cbfree(struct rcu_fwd *rfp) 2371 { 2372 unsigned long flags; 2373 unsigned long freed = 0; 2374 struct rcu_fwd_cb *rfcp; 2375 2376 for (;;) { 2377 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags); 2378 rfcp = rfp->rcu_fwd_cb_head; 2379 if (!rfcp) { 2380 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 2381 break; 2382 } 2383 rfp->rcu_fwd_cb_head = rfcp->rfc_next; 2384 if (!rfp->rcu_fwd_cb_head) 2385 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head; 2386 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 2387 kfree(rfcp); 2388 freed++; 2389 rcu_torture_fwd_prog_cond_resched(freed); 2390 if (tick_nohz_full_enabled()) { 2391 local_irq_save(flags); 2392 rcu_momentary_dyntick_idle(); 2393 local_irq_restore(flags); 2394 } 2395 } 2396 return freed; 2397 } 2398 2399 /* Carry out need_resched()/cond_resched() forward-progress testing. */ 2400 static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp, 2401 int *tested, int *tested_tries) 2402 { 2403 unsigned long cver; 2404 unsigned long dur; 2405 struct fwd_cb_state fcs; 2406 unsigned long gps; 2407 int idx; 2408 int sd; 2409 int sd4; 2410 bool selfpropcb = false; 2411 unsigned long stopat; 2412 static DEFINE_TORTURE_RANDOM(trs); 2413 2414 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id); 2415 if (!cur_ops->sync) 2416 return; // Cannot do need_resched() forward progress testing without ->sync. 2417 if (cur_ops->call && cur_ops->cb_barrier) { 2418 init_rcu_head_on_stack(&fcs.rh); 2419 selfpropcb = true; 2420 } 2421 2422 /* Tight loop containing cond_resched(). */ 2423 atomic_inc(&rcu_fwd_cb_nodelay); 2424 cur_ops->sync(); /* Later readers see above write. */ 2425 if (selfpropcb) { 2426 WRITE_ONCE(fcs.stop, 0); 2427 cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb); 2428 } 2429 cver = READ_ONCE(rcu_torture_current_version); 2430 gps = cur_ops->get_gp_seq(); 2431 sd = cur_ops->stall_dur() + 1; 2432 sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div; 2433 dur = sd4 + torture_random(&trs) % (sd - sd4); 2434 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies); 2435 stopat = rfp->rcu_fwd_startat + dur; 2436 while (time_before(jiffies, stopat) && 2437 !shutdown_time_arrived() && 2438 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 2439 idx = cur_ops->readlock(); 2440 udelay(10); 2441 cur_ops->readunlock(idx); 2442 if (!fwd_progress_need_resched || need_resched()) 2443 cond_resched(); 2444 } 2445 (*tested_tries)++; 2446 if (!time_before(jiffies, stopat) && 2447 !shutdown_time_arrived() && 2448 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 2449 (*tested)++; 2450 cver = READ_ONCE(rcu_torture_current_version) - cver; 2451 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps); 2452 WARN_ON(!cver && gps < 2); 2453 pr_alert("%s: %d Duration %ld cver %ld gps %ld\n", __func__, 2454 rfp->rcu_fwd_id, dur, cver, gps); 2455 } 2456 if (selfpropcb) { 2457 WRITE_ONCE(fcs.stop, 1); 2458 cur_ops->sync(); /* Wait for running CB to complete. */ 2459 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id); 2460 cur_ops->cb_barrier(); /* Wait for queued callbacks. */ 2461 } 2462 2463 if (selfpropcb) { 2464 WARN_ON(READ_ONCE(fcs.stop) != 2); 2465 destroy_rcu_head_on_stack(&fcs.rh); 2466 } 2467 schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */ 2468 atomic_dec(&rcu_fwd_cb_nodelay); 2469 } 2470 2471 /* Carry out call_rcu() forward-progress testing. */ 2472 static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp) 2473 { 2474 unsigned long cver; 2475 unsigned long flags; 2476 unsigned long gps; 2477 int i; 2478 long n_launders; 2479 long n_launders_cb_snap; 2480 long n_launders_sa; 2481 long n_max_cbs; 2482 long n_max_gps; 2483 struct rcu_fwd_cb *rfcp; 2484 struct rcu_fwd_cb *rfcpn; 2485 unsigned long stopat; 2486 unsigned long stoppedat; 2487 2488 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id); 2489 if (READ_ONCE(rcu_fwd_emergency_stop)) 2490 return; /* Get out of the way quickly, no GP wait! */ 2491 if (!cur_ops->call) 2492 return; /* Can't do call_rcu() fwd prog without ->call. */ 2493 2494 /* Loop continuously posting RCU callbacks. */ 2495 atomic_inc(&rcu_fwd_cb_nodelay); 2496 cur_ops->sync(); /* Later readers see above write. */ 2497 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies); 2498 stopat = rfp->rcu_fwd_startat + MAX_FWD_CB_JIFFIES; 2499 n_launders = 0; 2500 rfp->n_launders_cb = 0; // Hoist initialization for multi-kthread 2501 n_launders_sa = 0; 2502 n_max_cbs = 0; 2503 n_max_gps = 0; 2504 for (i = 0; i < ARRAY_SIZE(rfp->n_launders_hist); i++) 2505 rfp->n_launders_hist[i].n_launders = 0; 2506 cver = READ_ONCE(rcu_torture_current_version); 2507 gps = cur_ops->get_gp_seq(); 2508 rfp->rcu_launder_gp_seq_start = gps; 2509 tick_dep_set_task(current, TICK_DEP_BIT_RCU); 2510 while (time_before(jiffies, stopat) && 2511 !shutdown_time_arrived() && 2512 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 2513 rfcp = READ_ONCE(rfp->rcu_fwd_cb_head); 2514 rfcpn = NULL; 2515 if (rfcp) 2516 rfcpn = READ_ONCE(rfcp->rfc_next); 2517 if (rfcpn) { 2518 if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS && 2519 ++n_max_gps >= MIN_FWD_CBS_LAUNDERED) 2520 break; 2521 rfp->rcu_fwd_cb_head = rfcpn; 2522 n_launders++; 2523 n_launders_sa++; 2524 } else if (!cur_ops->cbflood_max || cur_ops->cbflood_max > n_max_cbs) { 2525 rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL); 2526 if (WARN_ON_ONCE(!rfcp)) { 2527 schedule_timeout_interruptible(1); 2528 continue; 2529 } 2530 n_max_cbs++; 2531 n_launders_sa = 0; 2532 rfcp->rfc_gps = 0; 2533 rfcp->rfc_rfp = rfp; 2534 } else { 2535 rfcp = NULL; 2536 } 2537 if (rfcp) 2538 cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr); 2539 rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs); 2540 if (tick_nohz_full_enabled()) { 2541 local_irq_save(flags); 2542 rcu_momentary_dyntick_idle(); 2543 local_irq_restore(flags); 2544 } 2545 } 2546 stoppedat = jiffies; 2547 n_launders_cb_snap = READ_ONCE(rfp->n_launders_cb); 2548 cver = READ_ONCE(rcu_torture_current_version) - cver; 2549 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps); 2550 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id); 2551 cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */ 2552 (void)rcu_torture_fwd_prog_cbfree(rfp); 2553 2554 if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) && 2555 !shutdown_time_arrived()) { 2556 WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED); 2557 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", 2558 __func__, 2559 stoppedat - rfp->rcu_fwd_startat, jiffies - stoppedat, 2560 n_launders + n_max_cbs - n_launders_cb_snap, 2561 n_launders, n_launders_sa, 2562 n_max_gps, n_max_cbs, cver, gps); 2563 atomic_long_add(n_max_cbs, &rcu_fwd_max_cbs); 2564 mutex_lock(&rcu_fwd_mutex); // Serialize histograms. 2565 rcu_torture_fwd_cb_hist(rfp); 2566 mutex_unlock(&rcu_fwd_mutex); 2567 } 2568 schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */ 2569 tick_dep_clear_task(current, TICK_DEP_BIT_RCU); 2570 atomic_dec(&rcu_fwd_cb_nodelay); 2571 } 2572 2573 2574 /* 2575 * OOM notifier, but this only prints diagnostic information for the 2576 * current forward-progress test. 2577 */ 2578 static int rcutorture_oom_notify(struct notifier_block *self, 2579 unsigned long notused, void *nfreed) 2580 { 2581 int i; 2582 long ncbs; 2583 struct rcu_fwd *rfp; 2584 2585 mutex_lock(&rcu_fwd_mutex); 2586 rfp = rcu_fwds; 2587 if (!rfp) { 2588 mutex_unlock(&rcu_fwd_mutex); 2589 return NOTIFY_OK; 2590 } 2591 WARN(1, "%s invoked upon OOM during forward-progress testing.\n", 2592 __func__); 2593 for (i = 0; i < fwd_progress; i++) { 2594 rcu_torture_fwd_cb_hist(&rfp[i]); 2595 rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp[i].rcu_fwd_startat)) / 2); 2596 } 2597 WRITE_ONCE(rcu_fwd_emergency_stop, true); 2598 smp_mb(); /* Emergency stop before free and wait to avoid hangs. */ 2599 ncbs = 0; 2600 for (i = 0; i < fwd_progress; i++) 2601 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]); 2602 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs); 2603 rcu_barrier(); 2604 ncbs = 0; 2605 for (i = 0; i < fwd_progress; i++) 2606 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]); 2607 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs); 2608 rcu_barrier(); 2609 ncbs = 0; 2610 for (i = 0; i < fwd_progress; i++) 2611 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]); 2612 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs); 2613 smp_mb(); /* Frees before return to avoid redoing OOM. */ 2614 (*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */ 2615 pr_info("%s returning after OOM processing.\n", __func__); 2616 mutex_unlock(&rcu_fwd_mutex); 2617 return NOTIFY_OK; 2618 } 2619 2620 static struct notifier_block rcutorture_oom_nb = { 2621 .notifier_call = rcutorture_oom_notify 2622 }; 2623 2624 /* Carry out grace-period forward-progress testing. */ 2625 static int rcu_torture_fwd_prog(void *args) 2626 { 2627 bool firsttime = true; 2628 long max_cbs; 2629 int oldnice = task_nice(current); 2630 unsigned long oldseq = READ_ONCE(rcu_fwd_seq); 2631 struct rcu_fwd *rfp = args; 2632 int tested = 0; 2633 int tested_tries = 0; 2634 2635 VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started"); 2636 rcu_bind_current_to_nocb(); 2637 if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST)) 2638 set_user_nice(current, MAX_NICE); 2639 do { 2640 if (!rfp->rcu_fwd_id) { 2641 schedule_timeout_interruptible(fwd_progress_holdoff * HZ); 2642 WRITE_ONCE(rcu_fwd_emergency_stop, false); 2643 if (!firsttime) { 2644 max_cbs = atomic_long_xchg(&rcu_fwd_max_cbs, 0); 2645 pr_alert("%s n_max_cbs: %ld\n", __func__, max_cbs); 2646 } 2647 firsttime = false; 2648 WRITE_ONCE(rcu_fwd_seq, rcu_fwd_seq + 1); 2649 } else { 2650 while (READ_ONCE(rcu_fwd_seq) == oldseq && !torture_must_stop()) 2651 schedule_timeout_interruptible(1); 2652 oldseq = READ_ONCE(rcu_fwd_seq); 2653 } 2654 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id); 2655 if (rcu_inkernel_boot_has_ended() && torture_num_online_cpus() > rfp->rcu_fwd_id) 2656 rcu_torture_fwd_prog_cr(rfp); 2657 if ((cur_ops->stall_dur && cur_ops->stall_dur() > 0) && 2658 (!IS_ENABLED(CONFIG_TINY_RCU) || 2659 (rcu_inkernel_boot_has_ended() && 2660 torture_num_online_cpus() > rfp->rcu_fwd_id))) 2661 rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries); 2662 2663 /* Avoid slow periods, better to test when busy. */ 2664 if (stutter_wait("rcu_torture_fwd_prog")) 2665 sched_set_normal(current, oldnice); 2666 } while (!torture_must_stop()); 2667 /* Short runs might not contain a valid forward-progress attempt. */ 2668 if (!rfp->rcu_fwd_id) { 2669 WARN_ON(!tested && tested_tries >= 5); 2670 pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries); 2671 } 2672 torture_kthread_stopping("rcu_torture_fwd_prog"); 2673 return 0; 2674 } 2675 2676 /* If forward-progress checking is requested and feasible, spawn the thread. */ 2677 static int __init rcu_torture_fwd_prog_init(void) 2678 { 2679 int i; 2680 int ret = 0; 2681 struct rcu_fwd *rfp; 2682 2683 if (!fwd_progress) 2684 return 0; /* Not requested, so don't do it. */ 2685 if (fwd_progress >= nr_cpu_ids) { 2686 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Limiting fwd_progress to # CPUs.\n"); 2687 fwd_progress = nr_cpu_ids; 2688 } else if (fwd_progress < 0) { 2689 fwd_progress = nr_cpu_ids; 2690 } 2691 if ((!cur_ops->sync && !cur_ops->call) || 2692 (!cur_ops->cbflood_max && (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0)) || 2693 cur_ops == &rcu_busted_ops) { 2694 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test"); 2695 fwd_progress = 0; 2696 return 0; 2697 } 2698 if (stall_cpu > 0) { 2699 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing"); 2700 fwd_progress = 0; 2701 if (IS_MODULE(CONFIG_RCU_TORTURE_TEST)) 2702 return -EINVAL; /* In module, can fail back to user. */ 2703 WARN_ON(1); /* Make sure rcutorture notices conflict. */ 2704 return 0; 2705 } 2706 if (fwd_progress_holdoff <= 0) 2707 fwd_progress_holdoff = 1; 2708 if (fwd_progress_div <= 0) 2709 fwd_progress_div = 4; 2710 rfp = kcalloc(fwd_progress, sizeof(*rfp), GFP_KERNEL); 2711 fwd_prog_tasks = kcalloc(fwd_progress, sizeof(*fwd_prog_tasks), GFP_KERNEL); 2712 if (!rfp || !fwd_prog_tasks) { 2713 kfree(rfp); 2714 kfree(fwd_prog_tasks); 2715 fwd_prog_tasks = NULL; 2716 fwd_progress = 0; 2717 return -ENOMEM; 2718 } 2719 for (i = 0; i < fwd_progress; i++) { 2720 spin_lock_init(&rfp[i].rcu_fwd_lock); 2721 rfp[i].rcu_fwd_cb_tail = &rfp[i].rcu_fwd_cb_head; 2722 rfp[i].rcu_fwd_id = i; 2723 } 2724 mutex_lock(&rcu_fwd_mutex); 2725 rcu_fwds = rfp; 2726 mutex_unlock(&rcu_fwd_mutex); 2727 register_oom_notifier(&rcutorture_oom_nb); 2728 for (i = 0; i < fwd_progress; i++) { 2729 ret = torture_create_kthread(rcu_torture_fwd_prog, &rcu_fwds[i], fwd_prog_tasks[i]); 2730 if (ret) { 2731 fwd_progress = i; 2732 return ret; 2733 } 2734 } 2735 return 0; 2736 } 2737 2738 static void rcu_torture_fwd_prog_cleanup(void) 2739 { 2740 int i; 2741 struct rcu_fwd *rfp; 2742 2743 if (!rcu_fwds || !fwd_prog_tasks) 2744 return; 2745 for (i = 0; i < fwd_progress; i++) 2746 torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_tasks[i]); 2747 unregister_oom_notifier(&rcutorture_oom_nb); 2748 mutex_lock(&rcu_fwd_mutex); 2749 rfp = rcu_fwds; 2750 rcu_fwds = NULL; 2751 mutex_unlock(&rcu_fwd_mutex); 2752 kfree(rfp); 2753 kfree(fwd_prog_tasks); 2754 fwd_prog_tasks = NULL; 2755 } 2756 2757 /* Callback function for RCU barrier testing. */ 2758 static void rcu_torture_barrier_cbf(struct rcu_head *rcu) 2759 { 2760 atomic_inc(&barrier_cbs_invoked); 2761 } 2762 2763 /* IPI handler to get callback posted on desired CPU, if online. */ 2764 static void rcu_torture_barrier1cb(void *rcu_void) 2765 { 2766 struct rcu_head *rhp = rcu_void; 2767 2768 cur_ops->call(rhp, rcu_torture_barrier_cbf); 2769 } 2770 2771 /* kthread function to register callbacks used to test RCU barriers. */ 2772 static int rcu_torture_barrier_cbs(void *arg) 2773 { 2774 long myid = (long)arg; 2775 bool lastphase = false; 2776 bool newphase; 2777 struct rcu_head rcu; 2778 2779 init_rcu_head_on_stack(&rcu); 2780 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started"); 2781 set_user_nice(current, MAX_NICE); 2782 do { 2783 wait_event(barrier_cbs_wq[myid], 2784 (newphase = 2785 smp_load_acquire(&barrier_phase)) != lastphase || 2786 torture_must_stop()); 2787 lastphase = newphase; 2788 if (torture_must_stop()) 2789 break; 2790 /* 2791 * The above smp_load_acquire() ensures barrier_phase load 2792 * is ordered before the following ->call(). 2793 */ 2794 if (smp_call_function_single(myid, rcu_torture_barrier1cb, 2795 &rcu, 1)) { 2796 // IPI failed, so use direct call from current CPU. 2797 cur_ops->call(&rcu, rcu_torture_barrier_cbf); 2798 } 2799 if (atomic_dec_and_test(&barrier_cbs_count)) 2800 wake_up(&barrier_wq); 2801 } while (!torture_must_stop()); 2802 if (cur_ops->cb_barrier != NULL) 2803 cur_ops->cb_barrier(); 2804 destroy_rcu_head_on_stack(&rcu); 2805 torture_kthread_stopping("rcu_torture_barrier_cbs"); 2806 return 0; 2807 } 2808 2809 /* kthread function to drive and coordinate RCU barrier testing. */ 2810 static int rcu_torture_barrier(void *arg) 2811 { 2812 int i; 2813 2814 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting"); 2815 do { 2816 atomic_set(&barrier_cbs_invoked, 0); 2817 atomic_set(&barrier_cbs_count, n_barrier_cbs); 2818 /* Ensure barrier_phase ordered after prior assignments. */ 2819 smp_store_release(&barrier_phase, !barrier_phase); 2820 for (i = 0; i < n_barrier_cbs; i++) 2821 wake_up(&barrier_cbs_wq[i]); 2822 wait_event(barrier_wq, 2823 atomic_read(&barrier_cbs_count) == 0 || 2824 torture_must_stop()); 2825 if (torture_must_stop()) 2826 break; 2827 n_barrier_attempts++; 2828 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */ 2829 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) { 2830 n_rcu_torture_barrier_error++; 2831 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n", 2832 atomic_read(&barrier_cbs_invoked), 2833 n_barrier_cbs); 2834 WARN_ON(1); 2835 // Wait manually for the remaining callbacks 2836 i = 0; 2837 do { 2838 if (WARN_ON(i++ > HZ)) 2839 i = INT_MIN; 2840 schedule_timeout_interruptible(1); 2841 cur_ops->cb_barrier(); 2842 } while (atomic_read(&barrier_cbs_invoked) != 2843 n_barrier_cbs && 2844 !torture_must_stop()); 2845 smp_mb(); // Can't trust ordering if broken. 2846 if (!torture_must_stop()) 2847 pr_err("Recovered: barrier_cbs_invoked = %d\n", 2848 atomic_read(&barrier_cbs_invoked)); 2849 } else { 2850 n_barrier_successes++; 2851 } 2852 schedule_timeout_interruptible(HZ / 10); 2853 } while (!torture_must_stop()); 2854 torture_kthread_stopping("rcu_torture_barrier"); 2855 return 0; 2856 } 2857 2858 /* Initialize RCU barrier testing. */ 2859 static int rcu_torture_barrier_init(void) 2860 { 2861 int i; 2862 int ret; 2863 2864 if (n_barrier_cbs <= 0) 2865 return 0; 2866 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) { 2867 pr_alert("%s" TORTURE_FLAG 2868 " Call or barrier ops missing for %s,\n", 2869 torture_type, cur_ops->name); 2870 pr_alert("%s" TORTURE_FLAG 2871 " RCU barrier testing omitted from run.\n", 2872 torture_type); 2873 return 0; 2874 } 2875 atomic_set(&barrier_cbs_count, 0); 2876 atomic_set(&barrier_cbs_invoked, 0); 2877 barrier_cbs_tasks = 2878 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]), 2879 GFP_KERNEL); 2880 barrier_cbs_wq = 2881 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL); 2882 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq) 2883 return -ENOMEM; 2884 for (i = 0; i < n_barrier_cbs; i++) { 2885 init_waitqueue_head(&barrier_cbs_wq[i]); 2886 ret = torture_create_kthread(rcu_torture_barrier_cbs, 2887 (void *)(long)i, 2888 barrier_cbs_tasks[i]); 2889 if (ret) 2890 return ret; 2891 } 2892 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task); 2893 } 2894 2895 /* Clean up after RCU barrier testing. */ 2896 static void rcu_torture_barrier_cleanup(void) 2897 { 2898 int i; 2899 2900 torture_stop_kthread(rcu_torture_barrier, barrier_task); 2901 if (barrier_cbs_tasks != NULL) { 2902 for (i = 0; i < n_barrier_cbs; i++) 2903 torture_stop_kthread(rcu_torture_barrier_cbs, 2904 barrier_cbs_tasks[i]); 2905 kfree(barrier_cbs_tasks); 2906 barrier_cbs_tasks = NULL; 2907 } 2908 if (barrier_cbs_wq != NULL) { 2909 kfree(barrier_cbs_wq); 2910 barrier_cbs_wq = NULL; 2911 } 2912 } 2913 2914 static bool rcu_torture_can_boost(void) 2915 { 2916 static int boost_warn_once; 2917 int prio; 2918 2919 if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2) 2920 return false; 2921 if (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state) 2922 return false; 2923 2924 prio = rcu_get_gp_kthreads_prio(); 2925 if (!prio) 2926 return false; 2927 2928 if (prio < 2) { 2929 if (boost_warn_once == 1) 2930 return false; 2931 2932 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); 2933 boost_warn_once = 1; 2934 return false; 2935 } 2936 2937 return true; 2938 } 2939 2940 static bool read_exit_child_stop; 2941 static bool read_exit_child_stopped; 2942 static wait_queue_head_t read_exit_wq; 2943 2944 // Child kthread which just does an rcutorture reader and exits. 2945 static int rcu_torture_read_exit_child(void *trsp_in) 2946 { 2947 struct torture_random_state *trsp = trsp_in; 2948 2949 set_user_nice(current, MAX_NICE); 2950 // Minimize time between reading and exiting. 2951 while (!kthread_should_stop()) 2952 schedule_timeout_uninterruptible(1); 2953 (void)rcu_torture_one_read(trsp, -1); 2954 return 0; 2955 } 2956 2957 // Parent kthread which creates and destroys read-exit child kthreads. 2958 static int rcu_torture_read_exit(void *unused) 2959 { 2960 bool errexit = false; 2961 int i; 2962 struct task_struct *tsp; 2963 DEFINE_TORTURE_RANDOM(trs); 2964 2965 // Allocate and initialize. 2966 set_user_nice(current, MAX_NICE); 2967 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of test"); 2968 2969 // Each pass through this loop does one read-exit episode. 2970 do { 2971 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of episode"); 2972 for (i = 0; i < read_exit_burst; i++) { 2973 if (READ_ONCE(read_exit_child_stop)) 2974 break; 2975 stutter_wait("rcu_torture_read_exit"); 2976 // Spawn child. 2977 tsp = kthread_run(rcu_torture_read_exit_child, 2978 &trs, "%s", "rcu_torture_read_exit_child"); 2979 if (IS_ERR(tsp)) { 2980 TOROUT_ERRSTRING("out of memory"); 2981 errexit = true; 2982 break; 2983 } 2984 cond_resched(); 2985 kthread_stop(tsp); 2986 n_read_exits++; 2987 } 2988 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: End of episode"); 2989 rcu_barrier(); // Wait for task_struct free, avoid OOM. 2990 i = 0; 2991 for (; !errexit && !READ_ONCE(read_exit_child_stop) && i < read_exit_delay; i++) 2992 schedule_timeout_uninterruptible(HZ); 2993 } while (!errexit && !READ_ONCE(read_exit_child_stop)); 2994 2995 // Clean up and exit. 2996 smp_store_release(&read_exit_child_stopped, true); // After reaping. 2997 smp_mb(); // Store before wakeup. 2998 wake_up(&read_exit_wq); 2999 while (!torture_must_stop()) 3000 schedule_timeout_uninterruptible(1); 3001 torture_kthread_stopping("rcu_torture_read_exit"); 3002 return 0; 3003 } 3004 3005 static int rcu_torture_read_exit_init(void) 3006 { 3007 if (read_exit_burst <= 0) 3008 return 0; 3009 init_waitqueue_head(&read_exit_wq); 3010 read_exit_child_stop = false; 3011 read_exit_child_stopped = false; 3012 return torture_create_kthread(rcu_torture_read_exit, NULL, 3013 read_exit_task); 3014 } 3015 3016 static void rcu_torture_read_exit_cleanup(void) 3017 { 3018 if (!read_exit_task) 3019 return; 3020 WRITE_ONCE(read_exit_child_stop, true); 3021 smp_mb(); // Above write before wait. 3022 wait_event(read_exit_wq, smp_load_acquire(&read_exit_child_stopped)); 3023 torture_stop_kthread(rcutorture_read_exit, read_exit_task); 3024 } 3025 3026 static enum cpuhp_state rcutor_hp; 3027 3028 static void 3029 rcu_torture_cleanup(void) 3030 { 3031 int firsttime; 3032 int flags = 0; 3033 unsigned long gp_seq = 0; 3034 int i; 3035 3036 if (torture_cleanup_begin()) { 3037 if (cur_ops->cb_barrier != NULL) { 3038 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier); 3039 cur_ops->cb_barrier(); 3040 } 3041 rcu_gp_slow_unregister(NULL); 3042 return; 3043 } 3044 if (!cur_ops) { 3045 torture_cleanup_end(); 3046 rcu_gp_slow_unregister(NULL); 3047 return; 3048 } 3049 3050 if (cur_ops->gp_kthread_dbg) 3051 cur_ops->gp_kthread_dbg(); 3052 rcu_torture_read_exit_cleanup(); 3053 rcu_torture_barrier_cleanup(); 3054 rcu_torture_fwd_prog_cleanup(); 3055 torture_stop_kthread(rcu_torture_stall, stall_task); 3056 torture_stop_kthread(rcu_torture_writer, writer_task); 3057 3058 if (nocb_tasks) { 3059 for (i = 0; i < nrealnocbers; i++) 3060 torture_stop_kthread(rcu_nocb_toggle, nocb_tasks[i]); 3061 kfree(nocb_tasks); 3062 nocb_tasks = NULL; 3063 } 3064 3065 if (reader_tasks) { 3066 for (i = 0; i < nrealreaders; i++) 3067 torture_stop_kthread(rcu_torture_reader, 3068 reader_tasks[i]); 3069 kfree(reader_tasks); 3070 reader_tasks = NULL; 3071 } 3072 kfree(rcu_torture_reader_mbchk); 3073 rcu_torture_reader_mbchk = NULL; 3074 3075 if (fakewriter_tasks) { 3076 for (i = 0; i < nfakewriters; i++) 3077 torture_stop_kthread(rcu_torture_fakewriter, 3078 fakewriter_tasks[i]); 3079 kfree(fakewriter_tasks); 3080 fakewriter_tasks = NULL; 3081 } 3082 3083 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq); 3084 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq); 3085 pr_alert("%s: End-test grace-period state: g%ld f%#x total-gps=%ld\n", 3086 cur_ops->name, (long)gp_seq, flags, 3087 rcutorture_seq_diff(gp_seq, start_gp_seq)); 3088 torture_stop_kthread(rcu_torture_stats, stats_task); 3089 torture_stop_kthread(rcu_torture_fqs, fqs_task); 3090 if (rcu_torture_can_boost() && rcutor_hp >= 0) 3091 cpuhp_remove_state(rcutor_hp); 3092 3093 /* 3094 * Wait for all RCU callbacks to fire, then do torture-type-specific 3095 * cleanup operations. 3096 */ 3097 if (cur_ops->cb_barrier != NULL) { 3098 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier); 3099 cur_ops->cb_barrier(); 3100 } 3101 if (cur_ops->cleanup != NULL) 3102 cur_ops->cleanup(); 3103 3104 rcu_torture_mem_dump_obj(); 3105 3106 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */ 3107 3108 if (err_segs_recorded) { 3109 pr_alert("Failure/close-call rcutorture reader segments:\n"); 3110 if (rt_read_nsegs == 0) 3111 pr_alert("\t: No segments recorded!!!\n"); 3112 firsttime = 1; 3113 for (i = 0; i < rt_read_nsegs; i++) { 3114 pr_alert("\t%d: %#x ", i, err_segs[i].rt_readstate); 3115 if (err_segs[i].rt_delay_jiffies != 0) { 3116 pr_cont("%s%ldjiffies", firsttime ? "" : "+", 3117 err_segs[i].rt_delay_jiffies); 3118 firsttime = 0; 3119 } 3120 if (err_segs[i].rt_delay_ms != 0) { 3121 pr_cont("%s%ldms", firsttime ? "" : "+", 3122 err_segs[i].rt_delay_ms); 3123 firsttime = 0; 3124 } 3125 if (err_segs[i].rt_delay_us != 0) { 3126 pr_cont("%s%ldus", firsttime ? "" : "+", 3127 err_segs[i].rt_delay_us); 3128 firsttime = 0; 3129 } 3130 pr_cont("%s\n", 3131 err_segs[i].rt_preempted ? "preempted" : ""); 3132 3133 } 3134 } 3135 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error) 3136 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE"); 3137 else if (torture_onoff_failures()) 3138 rcu_torture_print_module_parms(cur_ops, 3139 "End of test: RCU_HOTPLUG"); 3140 else 3141 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS"); 3142 torture_cleanup_end(); 3143 rcu_gp_slow_unregister(&rcu_fwd_cb_nodelay); 3144 } 3145 3146 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD 3147 static void rcu_torture_leak_cb(struct rcu_head *rhp) 3148 { 3149 } 3150 3151 static void rcu_torture_err_cb(struct rcu_head *rhp) 3152 { 3153 /* 3154 * This -might- happen due to race conditions, but is unlikely. 3155 * The scenario that leads to this happening is that the 3156 * first of the pair of duplicate callbacks is queued, 3157 * someone else starts a grace period that includes that 3158 * callback, then the second of the pair must wait for the 3159 * next grace period. Unlikely, but can happen. If it 3160 * does happen, the debug-objects subsystem won't have splatted. 3161 */ 3162 pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME); 3163 } 3164 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 3165 3166 /* 3167 * Verify that double-free causes debug-objects to complain, but only 3168 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test 3169 * cannot be carried out. 3170 */ 3171 static void rcu_test_debug_objects(void) 3172 { 3173 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD 3174 struct rcu_head rh1; 3175 struct rcu_head rh2; 3176 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_KERNEL); 3177 3178 init_rcu_head_on_stack(&rh1); 3179 init_rcu_head_on_stack(&rh2); 3180 pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME); 3181 3182 /* Try to queue the rh2 pair of callbacks for the same grace period. */ 3183 preempt_disable(); /* Prevent preemption from interrupting test. */ 3184 rcu_read_lock(); /* Make it impossible to finish a grace period. */ 3185 call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */ 3186 local_irq_disable(); /* Make it harder to start a new grace period. */ 3187 call_rcu(&rh2, rcu_torture_leak_cb); 3188 call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */ 3189 if (rhp) { 3190 call_rcu(rhp, rcu_torture_leak_cb); 3191 call_rcu(rhp, rcu_torture_err_cb); /* Another duplicate callback. */ 3192 } 3193 local_irq_enable(); 3194 rcu_read_unlock(); 3195 preempt_enable(); 3196 3197 /* Wait for them all to get done so we can safely return. */ 3198 rcu_barrier(); 3199 pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME); 3200 destroy_rcu_head_on_stack(&rh1); 3201 destroy_rcu_head_on_stack(&rh2); 3202 kfree(rhp); 3203 #else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 3204 pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME); 3205 #endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 3206 } 3207 3208 static void rcutorture_sync(void) 3209 { 3210 static unsigned long n; 3211 3212 if (cur_ops->sync && !(++n & 0xfff)) 3213 cur_ops->sync(); 3214 } 3215 3216 static int __init 3217 rcu_torture_init(void) 3218 { 3219 long i; 3220 int cpu; 3221 int firsterr = 0; 3222 int flags = 0; 3223 unsigned long gp_seq = 0; 3224 static struct rcu_torture_ops *torture_ops[] = { 3225 &rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops, &busted_srcud_ops, 3226 TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS 3227 &trivial_ops, 3228 }; 3229 3230 if (!torture_init_begin(torture_type, verbose)) 3231 return -EBUSY; 3232 3233 /* Process args and tell the world that the torturer is on the job. */ 3234 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) { 3235 cur_ops = torture_ops[i]; 3236 if (strcmp(torture_type, cur_ops->name) == 0) 3237 break; 3238 } 3239 if (i == ARRAY_SIZE(torture_ops)) { 3240 pr_alert("rcu-torture: invalid torture type: \"%s\"\n", 3241 torture_type); 3242 pr_alert("rcu-torture types:"); 3243 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) 3244 pr_cont(" %s", torture_ops[i]->name); 3245 pr_cont("\n"); 3246 firsterr = -EINVAL; 3247 cur_ops = NULL; 3248 goto unwind; 3249 } 3250 if (cur_ops->fqs == NULL && fqs_duration != 0) { 3251 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n"); 3252 fqs_duration = 0; 3253 } 3254 if (cur_ops->init) 3255 cur_ops->init(); 3256 3257 if (nreaders >= 0) { 3258 nrealreaders = nreaders; 3259 } else { 3260 nrealreaders = num_online_cpus() - 2 - nreaders; 3261 if (nrealreaders <= 0) 3262 nrealreaders = 1; 3263 } 3264 rcu_torture_print_module_parms(cur_ops, "Start of test"); 3265 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq); 3266 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq); 3267 start_gp_seq = gp_seq; 3268 pr_alert("%s: Start-test grace-period state: g%ld f%#x\n", 3269 cur_ops->name, (long)gp_seq, flags); 3270 3271 /* Set up the freelist. */ 3272 3273 INIT_LIST_HEAD(&rcu_torture_freelist); 3274 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) { 3275 rcu_tortures[i].rtort_mbtest = 0; 3276 list_add_tail(&rcu_tortures[i].rtort_free, 3277 &rcu_torture_freelist); 3278 } 3279 3280 /* Initialize the statistics so that each run gets its own numbers. */ 3281 3282 rcu_torture_current = NULL; 3283 rcu_torture_current_version = 0; 3284 atomic_set(&n_rcu_torture_alloc, 0); 3285 atomic_set(&n_rcu_torture_alloc_fail, 0); 3286 atomic_set(&n_rcu_torture_free, 0); 3287 atomic_set(&n_rcu_torture_mberror, 0); 3288 atomic_set(&n_rcu_torture_mbchk_fail, 0); 3289 atomic_set(&n_rcu_torture_mbchk_tries, 0); 3290 atomic_set(&n_rcu_torture_error, 0); 3291 n_rcu_torture_barrier_error = 0; 3292 n_rcu_torture_boost_ktrerror = 0; 3293 n_rcu_torture_boost_rterror = 0; 3294 n_rcu_torture_boost_failure = 0; 3295 n_rcu_torture_boosts = 0; 3296 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 3297 atomic_set(&rcu_torture_wcount[i], 0); 3298 for_each_possible_cpu(cpu) { 3299 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 3300 per_cpu(rcu_torture_count, cpu)[i] = 0; 3301 per_cpu(rcu_torture_batch, cpu)[i] = 0; 3302 } 3303 } 3304 err_segs_recorded = 0; 3305 rt_read_nsegs = 0; 3306 3307 /* Start up the kthreads. */ 3308 3309 rcu_torture_write_types(); 3310 firsterr = torture_create_kthread(rcu_torture_writer, NULL, 3311 writer_task); 3312 if (torture_init_error(firsterr)) 3313 goto unwind; 3314 if (nfakewriters > 0) { 3315 fakewriter_tasks = kcalloc(nfakewriters, 3316 sizeof(fakewriter_tasks[0]), 3317 GFP_KERNEL); 3318 if (fakewriter_tasks == NULL) { 3319 TOROUT_ERRSTRING("out of memory"); 3320 firsterr = -ENOMEM; 3321 goto unwind; 3322 } 3323 } 3324 for (i = 0; i < nfakewriters; i++) { 3325 firsterr = torture_create_kthread(rcu_torture_fakewriter, 3326 NULL, fakewriter_tasks[i]); 3327 if (torture_init_error(firsterr)) 3328 goto unwind; 3329 } 3330 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]), 3331 GFP_KERNEL); 3332 rcu_torture_reader_mbchk = kcalloc(nrealreaders, sizeof(*rcu_torture_reader_mbchk), 3333 GFP_KERNEL); 3334 if (!reader_tasks || !rcu_torture_reader_mbchk) { 3335 TOROUT_ERRSTRING("out of memory"); 3336 firsterr = -ENOMEM; 3337 goto unwind; 3338 } 3339 for (i = 0; i < nrealreaders; i++) { 3340 rcu_torture_reader_mbchk[i].rtc_chkrdr = -1; 3341 firsterr = torture_create_kthread(rcu_torture_reader, (void *)i, 3342 reader_tasks[i]); 3343 if (torture_init_error(firsterr)) 3344 goto unwind; 3345 } 3346 nrealnocbers = nocbs_nthreads; 3347 if (WARN_ON(nrealnocbers < 0)) 3348 nrealnocbers = 1; 3349 if (WARN_ON(nocbs_toggle < 0)) 3350 nocbs_toggle = HZ; 3351 if (nrealnocbers > 0) { 3352 nocb_tasks = kcalloc(nrealnocbers, sizeof(nocb_tasks[0]), GFP_KERNEL); 3353 if (nocb_tasks == NULL) { 3354 TOROUT_ERRSTRING("out of memory"); 3355 firsterr = -ENOMEM; 3356 goto unwind; 3357 } 3358 } else { 3359 nocb_tasks = NULL; 3360 } 3361 for (i = 0; i < nrealnocbers; i++) { 3362 firsterr = torture_create_kthread(rcu_nocb_toggle, NULL, nocb_tasks[i]); 3363 if (torture_init_error(firsterr)) 3364 goto unwind; 3365 } 3366 if (stat_interval > 0) { 3367 firsterr = torture_create_kthread(rcu_torture_stats, NULL, 3368 stats_task); 3369 if (torture_init_error(firsterr)) 3370 goto unwind; 3371 } 3372 if (test_no_idle_hz && shuffle_interval > 0) { 3373 firsterr = torture_shuffle_init(shuffle_interval * HZ); 3374 if (torture_init_error(firsterr)) 3375 goto unwind; 3376 } 3377 if (stutter < 0) 3378 stutter = 0; 3379 if (stutter) { 3380 int t; 3381 3382 t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ; 3383 firsterr = torture_stutter_init(stutter * HZ, t); 3384 if (torture_init_error(firsterr)) 3385 goto unwind; 3386 } 3387 if (fqs_duration < 0) 3388 fqs_duration = 0; 3389 if (fqs_duration) { 3390 /* Create the fqs thread */ 3391 firsterr = torture_create_kthread(rcu_torture_fqs, NULL, 3392 fqs_task); 3393 if (torture_init_error(firsterr)) 3394 goto unwind; 3395 } 3396 if (test_boost_interval < 1) 3397 test_boost_interval = 1; 3398 if (test_boost_duration < 2) 3399 test_boost_duration = 2; 3400 if (rcu_torture_can_boost()) { 3401 3402 boost_starttime = jiffies + test_boost_interval * HZ; 3403 3404 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE", 3405 rcutorture_booster_init, 3406 rcutorture_booster_cleanup); 3407 rcutor_hp = firsterr; 3408 if (torture_init_error(firsterr)) 3409 goto unwind; 3410 } 3411 shutdown_jiffies = jiffies + shutdown_secs * HZ; 3412 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup); 3413 if (torture_init_error(firsterr)) 3414 goto unwind; 3415 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval, 3416 rcutorture_sync); 3417 if (torture_init_error(firsterr)) 3418 goto unwind; 3419 firsterr = rcu_torture_stall_init(); 3420 if (torture_init_error(firsterr)) 3421 goto unwind; 3422 firsterr = rcu_torture_fwd_prog_init(); 3423 if (torture_init_error(firsterr)) 3424 goto unwind; 3425 firsterr = rcu_torture_barrier_init(); 3426 if (torture_init_error(firsterr)) 3427 goto unwind; 3428 firsterr = rcu_torture_read_exit_init(); 3429 if (torture_init_error(firsterr)) 3430 goto unwind; 3431 if (object_debug) 3432 rcu_test_debug_objects(); 3433 torture_init_end(); 3434 rcu_gp_slow_register(&rcu_fwd_cb_nodelay); 3435 return 0; 3436 3437 unwind: 3438 torture_init_end(); 3439 rcu_torture_cleanup(); 3440 if (shutdown_secs) { 3441 WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST)); 3442 kernel_power_off(); 3443 } 3444 return firsterr; 3445 } 3446 3447 module_init(rcu_torture_init); 3448 module_exit(rcu_torture_cleanup); 3449