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_cond_full, false, "Use conditional/async full-state GP wait primitives"); 88 torture_param(bool, gp_cond_exp_full, false, 89 "Use conditional/async full-stateexpedited GP wait primitives"); 90 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives"); 91 torture_param(bool, gp_normal, false, "Use normal (non-expedited) GP wait primitives"); 92 torture_param(bool, gp_poll, false, "Use polling GP wait primitives"); 93 torture_param(bool, gp_poll_exp, false, "Use polling expedited GP wait primitives"); 94 torture_param(bool, gp_poll_full, false, "Use polling full-state GP wait primitives"); 95 torture_param(bool, gp_poll_exp_full, false, "Use polling full-state expedited GP wait primitives"); 96 torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives"); 97 torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers"); 98 torture_param(int, leakpointer, 0, "Leak pointer dereferences from readers"); 99 torture_param(int, n_barrier_cbs, 0, "# of callbacks/kthreads for barrier testing"); 100 torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads"); 101 torture_param(int, nreaders, -1, "Number of RCU reader threads"); 102 torture_param(int, object_debug, 0, "Enable debug-object double call_rcu() testing"); 103 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)"); 104 torture_param(int, onoff_interval, 0, "Time between CPU hotplugs (jiffies), 0=disable"); 105 torture_param(int, nocbs_nthreads, 0, "Number of NOCB toggle threads, 0 to disable"); 106 torture_param(int, nocbs_toggle, 1000, "Time between toggling nocb state (ms)"); 107 torture_param(int, read_exit_delay, 13, "Delay between read-then-exit episodes (s)"); 108 torture_param(int, read_exit_burst, 16, "# of read-then-exit bursts per episode, zero to disable"); 109 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles"); 110 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable."); 111 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable."); 112 torture_param(int, stall_cpu_holdoff, 10, "Time to wait before starting stall (s)."); 113 torture_param(bool, stall_no_softlockup, false, "Avoid softlockup warning during cpu stall."); 114 torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling."); 115 torture_param(int, stall_cpu_block, 0, "Sleep while stalling."); 116 torture_param(int, stall_gp_kthread, 0, "Grace-period kthread stall duration (s)."); 117 torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s"); 118 torture_param(int, stutter, 5, "Number of seconds to run/halt test"); 119 torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes."); 120 torture_param(int, test_boost_duration, 4, "Duration of each boost test, seconds."); 121 torture_param(int, test_boost_interval, 7, "Interval between boost tests, seconds."); 122 torture_param(int, test_nmis, 0, "End-test NMI tests, 0 to disable."); 123 torture_param(bool, test_no_idle_hz, true, "Test support for tickless idle CPUs"); 124 torture_param(int, test_srcu_lockdep, 0, "Test specified SRCU deadlock scenario."); 125 torture_param(int, verbose, 1, "Enable verbose debugging printk()s"); 126 127 static char *torture_type = "rcu"; 128 module_param(torture_type, charp, 0444); 129 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, srcu, ...)"); 130 131 static int nrealnocbers; 132 static int nrealreaders; 133 static struct task_struct *writer_task; 134 static struct task_struct **fakewriter_tasks; 135 static struct task_struct **reader_tasks; 136 static struct task_struct **nocb_tasks; 137 static struct task_struct *stats_task; 138 static struct task_struct *fqs_task; 139 static struct task_struct *boost_tasks[NR_CPUS]; 140 static struct task_struct *stall_task; 141 static struct task_struct **fwd_prog_tasks; 142 static struct task_struct **barrier_cbs_tasks; 143 static struct task_struct *barrier_task; 144 static struct task_struct *read_exit_task; 145 146 #define RCU_TORTURE_PIPE_LEN 10 147 148 // Mailbox-like structure to check RCU global memory ordering. 149 struct rcu_torture_reader_check { 150 unsigned long rtc_myloops; 151 int rtc_chkrdr; 152 unsigned long rtc_chkloops; 153 int rtc_ready; 154 struct rcu_torture_reader_check *rtc_assigner; 155 } ____cacheline_internodealigned_in_smp; 156 157 // Update-side data structure used to check RCU readers. 158 struct rcu_torture { 159 struct rcu_head rtort_rcu; 160 int rtort_pipe_count; 161 struct list_head rtort_free; 162 int rtort_mbtest; 163 struct rcu_torture_reader_check *rtort_chkp; 164 }; 165 166 static LIST_HEAD(rcu_torture_freelist); 167 static struct rcu_torture __rcu *rcu_torture_current; 168 static unsigned long rcu_torture_current_version; 169 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN]; 170 static DEFINE_SPINLOCK(rcu_torture_lock); 171 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count); 172 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch); 173 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1]; 174 static struct rcu_torture_reader_check *rcu_torture_reader_mbchk; 175 static atomic_t n_rcu_torture_alloc; 176 static atomic_t n_rcu_torture_alloc_fail; 177 static atomic_t n_rcu_torture_free; 178 static atomic_t n_rcu_torture_mberror; 179 static atomic_t n_rcu_torture_mbchk_fail; 180 static atomic_t n_rcu_torture_mbchk_tries; 181 static atomic_t n_rcu_torture_error; 182 static long n_rcu_torture_barrier_error; 183 static long n_rcu_torture_boost_ktrerror; 184 static long n_rcu_torture_boost_failure; 185 static long n_rcu_torture_boosts; 186 static atomic_long_t n_rcu_torture_timers; 187 static long n_barrier_attempts; 188 static long n_barrier_successes; /* did rcu_barrier test succeed? */ 189 static unsigned long n_read_exits; 190 static struct list_head rcu_torture_removed; 191 static unsigned long shutdown_jiffies; 192 static unsigned long start_gp_seq; 193 static atomic_long_t n_nocb_offload; 194 static atomic_long_t n_nocb_deoffload; 195 196 static int rcu_torture_writer_state; 197 #define RTWS_FIXED_DELAY 0 198 #define RTWS_DELAY 1 199 #define RTWS_REPLACE 2 200 #define RTWS_DEF_FREE 3 201 #define RTWS_EXP_SYNC 4 202 #define RTWS_COND_GET 5 203 #define RTWS_COND_GET_FULL 6 204 #define RTWS_COND_GET_EXP 7 205 #define RTWS_COND_GET_EXP_FULL 8 206 #define RTWS_COND_SYNC 9 207 #define RTWS_COND_SYNC_FULL 10 208 #define RTWS_COND_SYNC_EXP 11 209 #define RTWS_COND_SYNC_EXP_FULL 12 210 #define RTWS_POLL_GET 13 211 #define RTWS_POLL_GET_FULL 14 212 #define RTWS_POLL_GET_EXP 15 213 #define RTWS_POLL_GET_EXP_FULL 16 214 #define RTWS_POLL_WAIT 17 215 #define RTWS_POLL_WAIT_FULL 18 216 #define RTWS_POLL_WAIT_EXP 19 217 #define RTWS_POLL_WAIT_EXP_FULL 20 218 #define RTWS_SYNC 21 219 #define RTWS_STUTTER 22 220 #define RTWS_STOPPING 23 221 static const char * const rcu_torture_writer_state_names[] = { 222 "RTWS_FIXED_DELAY", 223 "RTWS_DELAY", 224 "RTWS_REPLACE", 225 "RTWS_DEF_FREE", 226 "RTWS_EXP_SYNC", 227 "RTWS_COND_GET", 228 "RTWS_COND_GET_FULL", 229 "RTWS_COND_GET_EXP", 230 "RTWS_COND_GET_EXP_FULL", 231 "RTWS_COND_SYNC", 232 "RTWS_COND_SYNC_FULL", 233 "RTWS_COND_SYNC_EXP", 234 "RTWS_COND_SYNC_EXP_FULL", 235 "RTWS_POLL_GET", 236 "RTWS_POLL_GET_FULL", 237 "RTWS_POLL_GET_EXP", 238 "RTWS_POLL_GET_EXP_FULL", 239 "RTWS_POLL_WAIT", 240 "RTWS_POLL_WAIT_FULL", 241 "RTWS_POLL_WAIT_EXP", 242 "RTWS_POLL_WAIT_EXP_FULL", 243 "RTWS_SYNC", 244 "RTWS_STUTTER", 245 "RTWS_STOPPING", 246 }; 247 248 /* Record reader segment types and duration for first failing read. */ 249 struct rt_read_seg { 250 int rt_readstate; 251 unsigned long rt_delay_jiffies; 252 unsigned long rt_delay_ms; 253 unsigned long rt_delay_us; 254 bool rt_preempted; 255 }; 256 static int err_segs_recorded; 257 static struct rt_read_seg err_segs[RCUTORTURE_RDR_MAX_SEGS]; 258 static int rt_read_nsegs; 259 260 static const char *rcu_torture_writer_state_getname(void) 261 { 262 unsigned int i = READ_ONCE(rcu_torture_writer_state); 263 264 if (i >= ARRAY_SIZE(rcu_torture_writer_state_names)) 265 return "???"; 266 return rcu_torture_writer_state_names[i]; 267 } 268 269 #ifdef CONFIG_RCU_TRACE 270 static u64 notrace rcu_trace_clock_local(void) 271 { 272 u64 ts = trace_clock_local(); 273 274 (void)do_div(ts, NSEC_PER_USEC); 275 return ts; 276 } 277 #else /* #ifdef CONFIG_RCU_TRACE */ 278 static u64 notrace rcu_trace_clock_local(void) 279 { 280 return 0ULL; 281 } 282 #endif /* #else #ifdef CONFIG_RCU_TRACE */ 283 284 /* 285 * Stop aggressive CPU-hog tests a bit before the end of the test in order 286 * to avoid interfering with test shutdown. 287 */ 288 static bool shutdown_time_arrived(void) 289 { 290 return shutdown_secs && time_after(jiffies, shutdown_jiffies - 30 * HZ); 291 } 292 293 static unsigned long boost_starttime; /* jiffies of next boost test start. */ 294 static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */ 295 /* and boost task create/destroy. */ 296 static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */ 297 static bool barrier_phase; /* Test phase. */ 298 static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */ 299 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */ 300 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq); 301 302 static atomic_t rcu_fwd_cb_nodelay; /* Short rcu_torture_delay() delays. */ 303 304 /* 305 * Allocate an element from the rcu_tortures pool. 306 */ 307 static struct rcu_torture * 308 rcu_torture_alloc(void) 309 { 310 struct list_head *p; 311 312 spin_lock_bh(&rcu_torture_lock); 313 if (list_empty(&rcu_torture_freelist)) { 314 atomic_inc(&n_rcu_torture_alloc_fail); 315 spin_unlock_bh(&rcu_torture_lock); 316 return NULL; 317 } 318 atomic_inc(&n_rcu_torture_alloc); 319 p = rcu_torture_freelist.next; 320 list_del_init(p); 321 spin_unlock_bh(&rcu_torture_lock); 322 return container_of(p, struct rcu_torture, rtort_free); 323 } 324 325 /* 326 * Free an element to the rcu_tortures pool. 327 */ 328 static void 329 rcu_torture_free(struct rcu_torture *p) 330 { 331 atomic_inc(&n_rcu_torture_free); 332 spin_lock_bh(&rcu_torture_lock); 333 list_add_tail(&p->rtort_free, &rcu_torture_freelist); 334 spin_unlock_bh(&rcu_torture_lock); 335 } 336 337 /* 338 * Operations vector for selecting different types of tests. 339 */ 340 341 struct rcu_torture_ops { 342 int ttype; 343 void (*init)(void); 344 void (*cleanup)(void); 345 int (*readlock)(void); 346 void (*read_delay)(struct torture_random_state *rrsp, 347 struct rt_read_seg *rtrsp); 348 void (*readunlock)(int idx); 349 int (*readlock_held)(void); 350 unsigned long (*get_gp_seq)(void); 351 unsigned long (*gp_diff)(unsigned long new, unsigned long old); 352 void (*deferred_free)(struct rcu_torture *p); 353 void (*sync)(void); 354 void (*exp_sync)(void); 355 unsigned long (*get_gp_state_exp)(void); 356 unsigned long (*start_gp_poll_exp)(void); 357 void (*start_gp_poll_exp_full)(struct rcu_gp_oldstate *rgosp); 358 bool (*poll_gp_state_exp)(unsigned long oldstate); 359 void (*cond_sync_exp)(unsigned long oldstate); 360 void (*cond_sync_exp_full)(struct rcu_gp_oldstate *rgosp); 361 unsigned long (*get_comp_state)(void); 362 void (*get_comp_state_full)(struct rcu_gp_oldstate *rgosp); 363 bool (*same_gp_state)(unsigned long oldstate1, unsigned long oldstate2); 364 bool (*same_gp_state_full)(struct rcu_gp_oldstate *rgosp1, struct rcu_gp_oldstate *rgosp2); 365 unsigned long (*get_gp_state)(void); 366 void (*get_gp_state_full)(struct rcu_gp_oldstate *rgosp); 367 unsigned long (*get_gp_completed)(void); 368 void (*get_gp_completed_full)(struct rcu_gp_oldstate *rgosp); 369 unsigned long (*start_gp_poll)(void); 370 void (*start_gp_poll_full)(struct rcu_gp_oldstate *rgosp); 371 bool (*poll_gp_state)(unsigned long oldstate); 372 bool (*poll_gp_state_full)(struct rcu_gp_oldstate *rgosp); 373 bool (*poll_need_2gp)(bool poll, bool poll_full); 374 void (*cond_sync)(unsigned long oldstate); 375 void (*cond_sync_full)(struct rcu_gp_oldstate *rgosp); 376 call_rcu_func_t call; 377 void (*cb_barrier)(void); 378 void (*fqs)(void); 379 void (*stats)(void); 380 void (*gp_kthread_dbg)(void); 381 bool (*check_boost_failed)(unsigned long gp_state, int *cpup); 382 int (*stall_dur)(void); 383 long cbflood_max; 384 int irq_capable; 385 int can_boost; 386 int extendables; 387 int slow_gps; 388 int no_pi_lock; 389 const char *name; 390 }; 391 392 static struct rcu_torture_ops *cur_ops; 393 394 /* 395 * Definitions for rcu torture testing. 396 */ 397 398 static int torture_readlock_not_held(void) 399 { 400 return rcu_read_lock_bh_held() || rcu_read_lock_sched_held(); 401 } 402 403 static int rcu_torture_read_lock(void) 404 { 405 rcu_read_lock(); 406 return 0; 407 } 408 409 static void 410 rcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp) 411 { 412 unsigned long started; 413 unsigned long completed; 414 const unsigned long shortdelay_us = 200; 415 unsigned long longdelay_ms = 300; 416 unsigned long long ts; 417 418 /* We want a short delay sometimes to make a reader delay the grace 419 * period, and we want a long delay occasionally to trigger 420 * force_quiescent_state. */ 421 422 if (!atomic_read(&rcu_fwd_cb_nodelay) && 423 !(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) { 424 started = cur_ops->get_gp_seq(); 425 ts = rcu_trace_clock_local(); 426 if (preempt_count() & (SOFTIRQ_MASK | HARDIRQ_MASK)) 427 longdelay_ms = 5; /* Avoid triggering BH limits. */ 428 mdelay(longdelay_ms); 429 rtrsp->rt_delay_ms = longdelay_ms; 430 completed = cur_ops->get_gp_seq(); 431 do_trace_rcu_torture_read(cur_ops->name, NULL, ts, 432 started, completed); 433 } 434 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) { 435 udelay(shortdelay_us); 436 rtrsp->rt_delay_us = shortdelay_us; 437 } 438 if (!preempt_count() && 439 !(torture_random(rrsp) % (nrealreaders * 500))) { 440 torture_preempt_schedule(); /* QS only if preemptible. */ 441 rtrsp->rt_preempted = true; 442 } 443 } 444 445 static void rcu_torture_read_unlock(int idx) 446 { 447 rcu_read_unlock(); 448 } 449 450 /* 451 * Update callback in the pipe. This should be invoked after a grace period. 452 */ 453 static bool 454 rcu_torture_pipe_update_one(struct rcu_torture *rp) 455 { 456 int i; 457 struct rcu_torture_reader_check *rtrcp = READ_ONCE(rp->rtort_chkp); 458 459 if (rtrcp) { 460 WRITE_ONCE(rp->rtort_chkp, NULL); 461 smp_store_release(&rtrcp->rtc_ready, 1); // Pair with smp_load_acquire(). 462 } 463 i = READ_ONCE(rp->rtort_pipe_count); 464 if (i > RCU_TORTURE_PIPE_LEN) 465 i = RCU_TORTURE_PIPE_LEN; 466 atomic_inc(&rcu_torture_wcount[i]); 467 WRITE_ONCE(rp->rtort_pipe_count, i + 1); 468 if (rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) { 469 rp->rtort_mbtest = 0; 470 return true; 471 } 472 return false; 473 } 474 475 /* 476 * Update all callbacks in the pipe. Suitable for synchronous grace-period 477 * primitives. 478 */ 479 static void 480 rcu_torture_pipe_update(struct rcu_torture *old_rp) 481 { 482 struct rcu_torture *rp; 483 struct rcu_torture *rp1; 484 485 if (old_rp) 486 list_add(&old_rp->rtort_free, &rcu_torture_removed); 487 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) { 488 if (rcu_torture_pipe_update_one(rp)) { 489 list_del(&rp->rtort_free); 490 rcu_torture_free(rp); 491 } 492 } 493 } 494 495 static void 496 rcu_torture_cb(struct rcu_head *p) 497 { 498 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu); 499 500 if (torture_must_stop_irq()) { 501 /* Test is ending, just drop callbacks on the floor. */ 502 /* The next initialization will pick up the pieces. */ 503 return; 504 } 505 if (rcu_torture_pipe_update_one(rp)) 506 rcu_torture_free(rp); 507 else 508 cur_ops->deferred_free(rp); 509 } 510 511 static unsigned long rcu_no_completed(void) 512 { 513 return 0; 514 } 515 516 static void rcu_torture_deferred_free(struct rcu_torture *p) 517 { 518 call_rcu_hurry(&p->rtort_rcu, rcu_torture_cb); 519 } 520 521 static void rcu_sync_torture_init(void) 522 { 523 INIT_LIST_HEAD(&rcu_torture_removed); 524 } 525 526 static bool rcu_poll_need_2gp(bool poll, bool poll_full) 527 { 528 return poll; 529 } 530 531 static struct rcu_torture_ops rcu_ops = { 532 .ttype = RCU_FLAVOR, 533 .init = rcu_sync_torture_init, 534 .readlock = rcu_torture_read_lock, 535 .read_delay = rcu_read_delay, 536 .readunlock = rcu_torture_read_unlock, 537 .readlock_held = torture_readlock_not_held, 538 .get_gp_seq = rcu_get_gp_seq, 539 .gp_diff = rcu_seq_diff, 540 .deferred_free = rcu_torture_deferred_free, 541 .sync = synchronize_rcu, 542 .exp_sync = synchronize_rcu_expedited, 543 .same_gp_state = same_state_synchronize_rcu, 544 .same_gp_state_full = same_state_synchronize_rcu_full, 545 .get_comp_state = get_completed_synchronize_rcu, 546 .get_comp_state_full = get_completed_synchronize_rcu_full, 547 .get_gp_state = get_state_synchronize_rcu, 548 .get_gp_state_full = get_state_synchronize_rcu_full, 549 .get_gp_completed = get_completed_synchronize_rcu, 550 .get_gp_completed_full = get_completed_synchronize_rcu_full, 551 .start_gp_poll = start_poll_synchronize_rcu, 552 .start_gp_poll_full = start_poll_synchronize_rcu_full, 553 .poll_gp_state = poll_state_synchronize_rcu, 554 .poll_gp_state_full = poll_state_synchronize_rcu_full, 555 .poll_need_2gp = rcu_poll_need_2gp, 556 .cond_sync = cond_synchronize_rcu, 557 .cond_sync_full = cond_synchronize_rcu_full, 558 .get_gp_state_exp = get_state_synchronize_rcu, 559 .start_gp_poll_exp = start_poll_synchronize_rcu_expedited, 560 .start_gp_poll_exp_full = start_poll_synchronize_rcu_expedited_full, 561 .poll_gp_state_exp = poll_state_synchronize_rcu, 562 .cond_sync_exp = cond_synchronize_rcu_expedited, 563 .call = call_rcu_hurry, 564 .cb_barrier = rcu_barrier, 565 .fqs = rcu_force_quiescent_state, 566 .stats = NULL, 567 .gp_kthread_dbg = show_rcu_gp_kthreads, 568 .check_boost_failed = rcu_check_boost_fail, 569 .stall_dur = rcu_jiffies_till_stall_check, 570 .irq_capable = 1, 571 .can_boost = IS_ENABLED(CONFIG_RCU_BOOST), 572 .extendables = RCUTORTURE_MAX_EXTEND, 573 .name = "rcu" 574 }; 575 576 /* 577 * Don't even think about trying any of these in real life!!! 578 * The names includes "busted", and they really means it! 579 * The only purpose of these functions is to provide a buggy RCU 580 * implementation to make sure that rcutorture correctly emits 581 * buggy-RCU error messages. 582 */ 583 static void rcu_busted_torture_deferred_free(struct rcu_torture *p) 584 { 585 /* This is a deliberate bug for testing purposes only! */ 586 rcu_torture_cb(&p->rtort_rcu); 587 } 588 589 static void synchronize_rcu_busted(void) 590 { 591 /* This is a deliberate bug for testing purposes only! */ 592 } 593 594 static void 595 call_rcu_busted(struct rcu_head *head, rcu_callback_t func) 596 { 597 /* This is a deliberate bug for testing purposes only! */ 598 func(head); 599 } 600 601 static struct rcu_torture_ops rcu_busted_ops = { 602 .ttype = INVALID_RCU_FLAVOR, 603 .init = rcu_sync_torture_init, 604 .readlock = rcu_torture_read_lock, 605 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 606 .readunlock = rcu_torture_read_unlock, 607 .readlock_held = torture_readlock_not_held, 608 .get_gp_seq = rcu_no_completed, 609 .deferred_free = rcu_busted_torture_deferred_free, 610 .sync = synchronize_rcu_busted, 611 .exp_sync = synchronize_rcu_busted, 612 .call = call_rcu_busted, 613 .cb_barrier = NULL, 614 .fqs = NULL, 615 .stats = NULL, 616 .irq_capable = 1, 617 .name = "busted" 618 }; 619 620 /* 621 * Definitions for srcu torture testing. 622 */ 623 624 DEFINE_STATIC_SRCU(srcu_ctl); 625 static struct srcu_struct srcu_ctld; 626 static struct srcu_struct *srcu_ctlp = &srcu_ctl; 627 static struct rcu_torture_ops srcud_ops; 628 629 static int srcu_torture_read_lock(void) 630 { 631 if (cur_ops == &srcud_ops) 632 return srcu_read_lock_nmisafe(srcu_ctlp); 633 else 634 return srcu_read_lock(srcu_ctlp); 635 } 636 637 static void 638 srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp) 639 { 640 long delay; 641 const long uspertick = 1000000 / HZ; 642 const long longdelay = 10; 643 644 /* We want there to be long-running readers, but not all the time. */ 645 646 delay = torture_random(rrsp) % 647 (nrealreaders * 2 * longdelay * uspertick); 648 if (!delay && in_task()) { 649 schedule_timeout_interruptible(longdelay); 650 rtrsp->rt_delay_jiffies = longdelay; 651 } else { 652 rcu_read_delay(rrsp, rtrsp); 653 } 654 } 655 656 static void srcu_torture_read_unlock(int idx) 657 { 658 if (cur_ops == &srcud_ops) 659 srcu_read_unlock_nmisafe(srcu_ctlp, idx); 660 else 661 srcu_read_unlock(srcu_ctlp, idx); 662 } 663 664 static int torture_srcu_read_lock_held(void) 665 { 666 return srcu_read_lock_held(srcu_ctlp); 667 } 668 669 static unsigned long srcu_torture_completed(void) 670 { 671 return srcu_batches_completed(srcu_ctlp); 672 } 673 674 static void srcu_torture_deferred_free(struct rcu_torture *rp) 675 { 676 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb); 677 } 678 679 static void srcu_torture_synchronize(void) 680 { 681 synchronize_srcu(srcu_ctlp); 682 } 683 684 static unsigned long srcu_torture_get_gp_state(void) 685 { 686 return get_state_synchronize_srcu(srcu_ctlp); 687 } 688 689 static unsigned long srcu_torture_start_gp_poll(void) 690 { 691 return start_poll_synchronize_srcu(srcu_ctlp); 692 } 693 694 static bool srcu_torture_poll_gp_state(unsigned long oldstate) 695 { 696 return poll_state_synchronize_srcu(srcu_ctlp, oldstate); 697 } 698 699 static void srcu_torture_call(struct rcu_head *head, 700 rcu_callback_t func) 701 { 702 call_srcu(srcu_ctlp, head, func); 703 } 704 705 static void srcu_torture_barrier(void) 706 { 707 srcu_barrier(srcu_ctlp); 708 } 709 710 static void srcu_torture_stats(void) 711 { 712 srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG); 713 } 714 715 static void srcu_torture_synchronize_expedited(void) 716 { 717 synchronize_srcu_expedited(srcu_ctlp); 718 } 719 720 static struct rcu_torture_ops srcu_ops = { 721 .ttype = SRCU_FLAVOR, 722 .init = rcu_sync_torture_init, 723 .readlock = srcu_torture_read_lock, 724 .read_delay = srcu_read_delay, 725 .readunlock = srcu_torture_read_unlock, 726 .readlock_held = torture_srcu_read_lock_held, 727 .get_gp_seq = srcu_torture_completed, 728 .deferred_free = srcu_torture_deferred_free, 729 .sync = srcu_torture_synchronize, 730 .exp_sync = srcu_torture_synchronize_expedited, 731 .get_gp_state = srcu_torture_get_gp_state, 732 .start_gp_poll = srcu_torture_start_gp_poll, 733 .poll_gp_state = srcu_torture_poll_gp_state, 734 .call = srcu_torture_call, 735 .cb_barrier = srcu_torture_barrier, 736 .stats = srcu_torture_stats, 737 .cbflood_max = 50000, 738 .irq_capable = 1, 739 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU), 740 .name = "srcu" 741 }; 742 743 static void srcu_torture_init(void) 744 { 745 rcu_sync_torture_init(); 746 WARN_ON(init_srcu_struct(&srcu_ctld)); 747 srcu_ctlp = &srcu_ctld; 748 } 749 750 static void srcu_torture_cleanup(void) 751 { 752 cleanup_srcu_struct(&srcu_ctld); 753 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */ 754 } 755 756 /* As above, but dynamically allocated. */ 757 static struct rcu_torture_ops srcud_ops = { 758 .ttype = SRCU_FLAVOR, 759 .init = srcu_torture_init, 760 .cleanup = srcu_torture_cleanup, 761 .readlock = srcu_torture_read_lock, 762 .read_delay = srcu_read_delay, 763 .readunlock = srcu_torture_read_unlock, 764 .readlock_held = torture_srcu_read_lock_held, 765 .get_gp_seq = srcu_torture_completed, 766 .deferred_free = srcu_torture_deferred_free, 767 .sync = srcu_torture_synchronize, 768 .exp_sync = srcu_torture_synchronize_expedited, 769 .get_gp_state = srcu_torture_get_gp_state, 770 .start_gp_poll = srcu_torture_start_gp_poll, 771 .poll_gp_state = srcu_torture_poll_gp_state, 772 .call = srcu_torture_call, 773 .cb_barrier = srcu_torture_barrier, 774 .stats = srcu_torture_stats, 775 .cbflood_max = 50000, 776 .irq_capable = 1, 777 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU), 778 .name = "srcud" 779 }; 780 781 /* As above, but broken due to inappropriate reader extension. */ 782 static struct rcu_torture_ops busted_srcud_ops = { 783 .ttype = SRCU_FLAVOR, 784 .init = srcu_torture_init, 785 .cleanup = srcu_torture_cleanup, 786 .readlock = srcu_torture_read_lock, 787 .read_delay = rcu_read_delay, 788 .readunlock = srcu_torture_read_unlock, 789 .readlock_held = torture_srcu_read_lock_held, 790 .get_gp_seq = srcu_torture_completed, 791 .deferred_free = srcu_torture_deferred_free, 792 .sync = srcu_torture_synchronize, 793 .exp_sync = srcu_torture_synchronize_expedited, 794 .call = srcu_torture_call, 795 .cb_barrier = srcu_torture_barrier, 796 .stats = srcu_torture_stats, 797 .irq_capable = 1, 798 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU), 799 .extendables = RCUTORTURE_MAX_EXTEND, 800 .name = "busted_srcud" 801 }; 802 803 /* 804 * Definitions for trivial CONFIG_PREEMPT=n-only torture testing. 805 * This implementation does not necessarily work well with CPU hotplug. 806 */ 807 808 static void synchronize_rcu_trivial(void) 809 { 810 int cpu; 811 812 for_each_online_cpu(cpu) { 813 rcutorture_sched_setaffinity(current->pid, cpumask_of(cpu)); 814 WARN_ON_ONCE(raw_smp_processor_id() != cpu); 815 } 816 } 817 818 static int rcu_torture_read_lock_trivial(void) 819 { 820 preempt_disable(); 821 return 0; 822 } 823 824 static void rcu_torture_read_unlock_trivial(int idx) 825 { 826 preempt_enable(); 827 } 828 829 static struct rcu_torture_ops trivial_ops = { 830 .ttype = RCU_TRIVIAL_FLAVOR, 831 .init = rcu_sync_torture_init, 832 .readlock = rcu_torture_read_lock_trivial, 833 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 834 .readunlock = rcu_torture_read_unlock_trivial, 835 .readlock_held = torture_readlock_not_held, 836 .get_gp_seq = rcu_no_completed, 837 .sync = synchronize_rcu_trivial, 838 .exp_sync = synchronize_rcu_trivial, 839 .fqs = NULL, 840 .stats = NULL, 841 .irq_capable = 1, 842 .name = "trivial" 843 }; 844 845 #ifdef CONFIG_TASKS_RCU 846 847 /* 848 * Definitions for RCU-tasks torture testing. 849 */ 850 851 static int tasks_torture_read_lock(void) 852 { 853 return 0; 854 } 855 856 static void tasks_torture_read_unlock(int idx) 857 { 858 } 859 860 static void rcu_tasks_torture_deferred_free(struct rcu_torture *p) 861 { 862 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb); 863 } 864 865 static void synchronize_rcu_mult_test(void) 866 { 867 synchronize_rcu_mult(call_rcu_tasks, call_rcu_hurry); 868 } 869 870 static struct rcu_torture_ops tasks_ops = { 871 .ttype = RCU_TASKS_FLAVOR, 872 .init = rcu_sync_torture_init, 873 .readlock = tasks_torture_read_lock, 874 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 875 .readunlock = tasks_torture_read_unlock, 876 .get_gp_seq = rcu_no_completed, 877 .deferred_free = rcu_tasks_torture_deferred_free, 878 .sync = synchronize_rcu_tasks, 879 .exp_sync = synchronize_rcu_mult_test, 880 .call = call_rcu_tasks, 881 .cb_barrier = rcu_barrier_tasks, 882 .gp_kthread_dbg = show_rcu_tasks_classic_gp_kthread, 883 .fqs = NULL, 884 .stats = NULL, 885 .irq_capable = 1, 886 .slow_gps = 1, 887 .name = "tasks" 888 }; 889 890 #define TASKS_OPS &tasks_ops, 891 892 #else // #ifdef CONFIG_TASKS_RCU 893 894 #define TASKS_OPS 895 896 #endif // #else #ifdef CONFIG_TASKS_RCU 897 898 899 #ifdef CONFIG_TASKS_RUDE_RCU 900 901 /* 902 * Definitions for rude RCU-tasks torture testing. 903 */ 904 905 static void rcu_tasks_rude_torture_deferred_free(struct rcu_torture *p) 906 { 907 call_rcu_tasks_rude(&p->rtort_rcu, rcu_torture_cb); 908 } 909 910 static struct rcu_torture_ops tasks_rude_ops = { 911 .ttype = RCU_TASKS_RUDE_FLAVOR, 912 .init = rcu_sync_torture_init, 913 .readlock = rcu_torture_read_lock_trivial, 914 .read_delay = rcu_read_delay, /* just reuse rcu's version. */ 915 .readunlock = rcu_torture_read_unlock_trivial, 916 .get_gp_seq = rcu_no_completed, 917 .deferred_free = rcu_tasks_rude_torture_deferred_free, 918 .sync = synchronize_rcu_tasks_rude, 919 .exp_sync = synchronize_rcu_tasks_rude, 920 .call = call_rcu_tasks_rude, 921 .cb_barrier = rcu_barrier_tasks_rude, 922 .gp_kthread_dbg = show_rcu_tasks_rude_gp_kthread, 923 .cbflood_max = 50000, 924 .fqs = NULL, 925 .stats = NULL, 926 .irq_capable = 1, 927 .name = "tasks-rude" 928 }; 929 930 #define TASKS_RUDE_OPS &tasks_rude_ops, 931 932 #else // #ifdef CONFIG_TASKS_RUDE_RCU 933 934 #define TASKS_RUDE_OPS 935 936 #endif // #else #ifdef CONFIG_TASKS_RUDE_RCU 937 938 939 #ifdef CONFIG_TASKS_TRACE_RCU 940 941 /* 942 * Definitions for tracing RCU-tasks torture testing. 943 */ 944 945 static int tasks_tracing_torture_read_lock(void) 946 { 947 rcu_read_lock_trace(); 948 return 0; 949 } 950 951 static void tasks_tracing_torture_read_unlock(int idx) 952 { 953 rcu_read_unlock_trace(); 954 } 955 956 static void rcu_tasks_tracing_torture_deferred_free(struct rcu_torture *p) 957 { 958 call_rcu_tasks_trace(&p->rtort_rcu, rcu_torture_cb); 959 } 960 961 static struct rcu_torture_ops tasks_tracing_ops = { 962 .ttype = RCU_TASKS_TRACING_FLAVOR, 963 .init = rcu_sync_torture_init, 964 .readlock = tasks_tracing_torture_read_lock, 965 .read_delay = srcu_read_delay, /* just reuse srcu's version. */ 966 .readunlock = tasks_tracing_torture_read_unlock, 967 .readlock_held = rcu_read_lock_trace_held, 968 .get_gp_seq = rcu_no_completed, 969 .deferred_free = rcu_tasks_tracing_torture_deferred_free, 970 .sync = synchronize_rcu_tasks_trace, 971 .exp_sync = synchronize_rcu_tasks_trace, 972 .call = call_rcu_tasks_trace, 973 .cb_barrier = rcu_barrier_tasks_trace, 974 .gp_kthread_dbg = show_rcu_tasks_trace_gp_kthread, 975 .cbflood_max = 50000, 976 .fqs = NULL, 977 .stats = NULL, 978 .irq_capable = 1, 979 .slow_gps = 1, 980 .name = "tasks-tracing" 981 }; 982 983 #define TASKS_TRACING_OPS &tasks_tracing_ops, 984 985 #else // #ifdef CONFIG_TASKS_TRACE_RCU 986 987 #define TASKS_TRACING_OPS 988 989 #endif // #else #ifdef CONFIG_TASKS_TRACE_RCU 990 991 992 static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old) 993 { 994 if (!cur_ops->gp_diff) 995 return new - old; 996 return cur_ops->gp_diff(new, old); 997 } 998 999 /* 1000 * RCU torture priority-boost testing. Runs one real-time thread per 1001 * CPU for moderate bursts, repeatedly starting grace periods and waiting 1002 * for them to complete. If a given grace period takes too long, we assume 1003 * that priority inversion has occurred. 1004 */ 1005 1006 static int old_rt_runtime = -1; 1007 1008 static void rcu_torture_disable_rt_throttle(void) 1009 { 1010 /* 1011 * Disable RT throttling so that rcutorture's boost threads don't get 1012 * throttled. Only possible if rcutorture is built-in otherwise the 1013 * user should manually do this by setting the sched_rt_period_us and 1014 * sched_rt_runtime sysctls. 1015 */ 1016 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime != -1) 1017 return; 1018 1019 old_rt_runtime = sysctl_sched_rt_runtime; 1020 sysctl_sched_rt_runtime = -1; 1021 } 1022 1023 static void rcu_torture_enable_rt_throttle(void) 1024 { 1025 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime == -1) 1026 return; 1027 1028 sysctl_sched_rt_runtime = old_rt_runtime; 1029 old_rt_runtime = -1; 1030 } 1031 1032 static bool rcu_torture_boost_failed(unsigned long gp_state, unsigned long *start) 1033 { 1034 int cpu; 1035 static int dbg_done; 1036 unsigned long end = jiffies; 1037 bool gp_done; 1038 unsigned long j; 1039 static unsigned long last_persist; 1040 unsigned long lp; 1041 unsigned long mininterval = test_boost_duration * HZ - HZ / 2; 1042 1043 if (end - *start > mininterval) { 1044 // Recheck after checking time to avoid false positives. 1045 smp_mb(); // Time check before grace-period check. 1046 if (cur_ops->poll_gp_state(gp_state)) 1047 return false; // passed, though perhaps just barely 1048 if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, &cpu)) { 1049 // At most one persisted message per boost test. 1050 j = jiffies; 1051 lp = READ_ONCE(last_persist); 1052 if (time_after(j, lp + mininterval) && cmpxchg(&last_persist, lp, j) == lp) 1053 pr_info("Boost inversion persisted: No QS from CPU %d\n", cpu); 1054 return false; // passed on a technicality 1055 } 1056 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed"); 1057 n_rcu_torture_boost_failure++; 1058 if (!xchg(&dbg_done, 1) && cur_ops->gp_kthread_dbg) { 1059 pr_info("Boost inversion thread ->rt_priority %u gp_state %lu jiffies %lu\n", 1060 current->rt_priority, gp_state, end - *start); 1061 cur_ops->gp_kthread_dbg(); 1062 // Recheck after print to flag grace period ending during splat. 1063 gp_done = cur_ops->poll_gp_state(gp_state); 1064 pr_info("Boost inversion: GP %lu %s.\n", gp_state, 1065 gp_done ? "ended already" : "still pending"); 1066 1067 } 1068 1069 return true; // failed 1070 } else if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, NULL)) { 1071 *start = jiffies; 1072 } 1073 1074 return false; // passed 1075 } 1076 1077 static int rcu_torture_boost(void *arg) 1078 { 1079 unsigned long endtime; 1080 unsigned long gp_state; 1081 unsigned long gp_state_time; 1082 unsigned long oldstarttime; 1083 1084 VERBOSE_TOROUT_STRING("rcu_torture_boost started"); 1085 1086 /* Set real-time priority. */ 1087 sched_set_fifo_low(current); 1088 1089 /* Each pass through the following loop does one boost-test cycle. */ 1090 do { 1091 bool failed = false; // Test failed already in this test interval 1092 bool gp_initiated = false; 1093 1094 if (kthread_should_stop()) 1095 goto checkwait; 1096 1097 /* Wait for the next test interval. */ 1098 oldstarttime = READ_ONCE(boost_starttime); 1099 while (time_before(jiffies, oldstarttime)) { 1100 schedule_timeout_interruptible(oldstarttime - jiffies); 1101 if (stutter_wait("rcu_torture_boost")) 1102 sched_set_fifo_low(current); 1103 if (torture_must_stop()) 1104 goto checkwait; 1105 } 1106 1107 // Do one boost-test interval. 1108 endtime = oldstarttime + test_boost_duration * HZ; 1109 while (time_before(jiffies, endtime)) { 1110 // Has current GP gone too long? 1111 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state)) 1112 failed = rcu_torture_boost_failed(gp_state, &gp_state_time); 1113 // If we don't have a grace period in flight, start one. 1114 if (!gp_initiated || cur_ops->poll_gp_state(gp_state)) { 1115 gp_state = cur_ops->start_gp_poll(); 1116 gp_initiated = true; 1117 gp_state_time = jiffies; 1118 } 1119 if (stutter_wait("rcu_torture_boost")) { 1120 sched_set_fifo_low(current); 1121 // If the grace period already ended, 1122 // we don't know when that happened, so 1123 // start over. 1124 if (cur_ops->poll_gp_state(gp_state)) 1125 gp_initiated = false; 1126 } 1127 if (torture_must_stop()) 1128 goto checkwait; 1129 } 1130 1131 // In case the grace period extended beyond the end of the loop. 1132 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state)) 1133 rcu_torture_boost_failed(gp_state, &gp_state_time); 1134 1135 /* 1136 * Set the start time of the next test interval. 1137 * Yes, this is vulnerable to long delays, but such 1138 * delays simply cause a false negative for the next 1139 * interval. Besides, we are running at RT priority, 1140 * so delays should be relatively rare. 1141 */ 1142 while (oldstarttime == READ_ONCE(boost_starttime) && !kthread_should_stop()) { 1143 if (mutex_trylock(&boost_mutex)) { 1144 if (oldstarttime == boost_starttime) { 1145 WRITE_ONCE(boost_starttime, 1146 jiffies + test_boost_interval * HZ); 1147 n_rcu_torture_boosts++; 1148 } 1149 mutex_unlock(&boost_mutex); 1150 break; 1151 } 1152 schedule_timeout_uninterruptible(1); 1153 } 1154 1155 /* Go do the stutter. */ 1156 checkwait: if (stutter_wait("rcu_torture_boost")) 1157 sched_set_fifo_low(current); 1158 } while (!torture_must_stop()); 1159 1160 /* Clean up and exit. */ 1161 while (!kthread_should_stop()) { 1162 torture_shutdown_absorb("rcu_torture_boost"); 1163 schedule_timeout_uninterruptible(1); 1164 } 1165 torture_kthread_stopping("rcu_torture_boost"); 1166 return 0; 1167 } 1168 1169 /* 1170 * RCU torture force-quiescent-state kthread. Repeatedly induces 1171 * bursts of calls to force_quiescent_state(), increasing the probability 1172 * of occurrence of some important types of race conditions. 1173 */ 1174 static int 1175 rcu_torture_fqs(void *arg) 1176 { 1177 unsigned long fqs_resume_time; 1178 int fqs_burst_remaining; 1179 int oldnice = task_nice(current); 1180 1181 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started"); 1182 do { 1183 fqs_resume_time = jiffies + fqs_stutter * HZ; 1184 while (time_before(jiffies, fqs_resume_time) && 1185 !kthread_should_stop()) { 1186 schedule_timeout_interruptible(1); 1187 } 1188 fqs_burst_remaining = fqs_duration; 1189 while (fqs_burst_remaining > 0 && 1190 !kthread_should_stop()) { 1191 cur_ops->fqs(); 1192 udelay(fqs_holdoff); 1193 fqs_burst_remaining -= fqs_holdoff; 1194 } 1195 if (stutter_wait("rcu_torture_fqs")) 1196 sched_set_normal(current, oldnice); 1197 } while (!torture_must_stop()); 1198 torture_kthread_stopping("rcu_torture_fqs"); 1199 return 0; 1200 } 1201 1202 // Used by writers to randomly choose from the available grace-period primitives. 1203 static int synctype[ARRAY_SIZE(rcu_torture_writer_state_names)] = { }; 1204 static int nsynctypes; 1205 1206 /* 1207 * Determine which grace-period primitives are available. 1208 */ 1209 static void rcu_torture_write_types(void) 1210 { 1211 bool gp_cond1 = gp_cond, gp_cond_exp1 = gp_cond_exp, gp_cond_full1 = gp_cond_full; 1212 bool gp_cond_exp_full1 = gp_cond_exp_full, gp_exp1 = gp_exp, gp_poll_exp1 = gp_poll_exp; 1213 bool gp_poll_exp_full1 = gp_poll_exp_full, gp_normal1 = gp_normal, gp_poll1 = gp_poll; 1214 bool gp_poll_full1 = gp_poll_full, gp_sync1 = gp_sync; 1215 1216 /* Initialize synctype[] array. If none set, take default. */ 1217 if (!gp_cond1 && 1218 !gp_cond_exp1 && 1219 !gp_cond_full1 && 1220 !gp_cond_exp_full1 && 1221 !gp_exp1 && 1222 !gp_poll_exp1 && 1223 !gp_poll_exp_full1 && 1224 !gp_normal1 && 1225 !gp_poll1 && 1226 !gp_poll_full1 && 1227 !gp_sync1) { 1228 gp_cond1 = true; 1229 gp_cond_exp1 = true; 1230 gp_cond_full1 = true; 1231 gp_cond_exp_full1 = true; 1232 gp_exp1 = true; 1233 gp_poll_exp1 = true; 1234 gp_poll_exp_full1 = true; 1235 gp_normal1 = true; 1236 gp_poll1 = true; 1237 gp_poll_full1 = true; 1238 gp_sync1 = true; 1239 } 1240 if (gp_cond1 && cur_ops->get_gp_state && cur_ops->cond_sync) { 1241 synctype[nsynctypes++] = RTWS_COND_GET; 1242 pr_info("%s: Testing conditional GPs.\n", __func__); 1243 } else if (gp_cond && (!cur_ops->get_gp_state || !cur_ops->cond_sync)) { 1244 pr_alert("%s: gp_cond without primitives.\n", __func__); 1245 } 1246 if (gp_cond_exp1 && cur_ops->get_gp_state_exp && cur_ops->cond_sync_exp) { 1247 synctype[nsynctypes++] = RTWS_COND_GET_EXP; 1248 pr_info("%s: Testing conditional expedited GPs.\n", __func__); 1249 } else if (gp_cond_exp && (!cur_ops->get_gp_state_exp || !cur_ops->cond_sync_exp)) { 1250 pr_alert("%s: gp_cond_exp without primitives.\n", __func__); 1251 } 1252 if (gp_cond_full1 && cur_ops->get_gp_state && cur_ops->cond_sync_full) { 1253 synctype[nsynctypes++] = RTWS_COND_GET_FULL; 1254 pr_info("%s: Testing conditional full-state GPs.\n", __func__); 1255 } else if (gp_cond_full && (!cur_ops->get_gp_state || !cur_ops->cond_sync_full)) { 1256 pr_alert("%s: gp_cond_full without primitives.\n", __func__); 1257 } 1258 if (gp_cond_exp_full1 && cur_ops->get_gp_state_exp && cur_ops->cond_sync_exp_full) { 1259 synctype[nsynctypes++] = RTWS_COND_GET_EXP_FULL; 1260 pr_info("%s: Testing conditional full-state expedited GPs.\n", __func__); 1261 } else if (gp_cond_exp_full && 1262 (!cur_ops->get_gp_state_exp || !cur_ops->cond_sync_exp_full)) { 1263 pr_alert("%s: gp_cond_exp_full without primitives.\n", __func__); 1264 } 1265 if (gp_exp1 && cur_ops->exp_sync) { 1266 synctype[nsynctypes++] = RTWS_EXP_SYNC; 1267 pr_info("%s: Testing expedited GPs.\n", __func__); 1268 } else if (gp_exp && !cur_ops->exp_sync) { 1269 pr_alert("%s: gp_exp without primitives.\n", __func__); 1270 } 1271 if (gp_normal1 && cur_ops->deferred_free) { 1272 synctype[nsynctypes++] = RTWS_DEF_FREE; 1273 pr_info("%s: Testing asynchronous GPs.\n", __func__); 1274 } else if (gp_normal && !cur_ops->deferred_free) { 1275 pr_alert("%s: gp_normal without primitives.\n", __func__); 1276 } 1277 if (gp_poll1 && cur_ops->get_comp_state && cur_ops->same_gp_state && 1278 cur_ops->start_gp_poll && cur_ops->poll_gp_state) { 1279 synctype[nsynctypes++] = RTWS_POLL_GET; 1280 pr_info("%s: Testing polling GPs.\n", __func__); 1281 } else if (gp_poll && (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)) { 1282 pr_alert("%s: gp_poll without primitives.\n", __func__); 1283 } 1284 if (gp_poll_full1 && cur_ops->get_comp_state_full && cur_ops->same_gp_state_full 1285 && cur_ops->start_gp_poll_full && cur_ops->poll_gp_state_full) { 1286 synctype[nsynctypes++] = RTWS_POLL_GET_FULL; 1287 pr_info("%s: Testing polling full-state GPs.\n", __func__); 1288 } else if (gp_poll_full && (!cur_ops->start_gp_poll_full || !cur_ops->poll_gp_state_full)) { 1289 pr_alert("%s: gp_poll_full without primitives.\n", __func__); 1290 } 1291 if (gp_poll_exp1 && cur_ops->start_gp_poll_exp && cur_ops->poll_gp_state_exp) { 1292 synctype[nsynctypes++] = RTWS_POLL_GET_EXP; 1293 pr_info("%s: Testing polling expedited GPs.\n", __func__); 1294 } else if (gp_poll_exp && (!cur_ops->start_gp_poll_exp || !cur_ops->poll_gp_state_exp)) { 1295 pr_alert("%s: gp_poll_exp without primitives.\n", __func__); 1296 } 1297 if (gp_poll_exp_full1 && cur_ops->start_gp_poll_exp_full && cur_ops->poll_gp_state_full) { 1298 synctype[nsynctypes++] = RTWS_POLL_GET_EXP_FULL; 1299 pr_info("%s: Testing polling full-state expedited GPs.\n", __func__); 1300 } else if (gp_poll_exp_full && 1301 (!cur_ops->start_gp_poll_exp_full || !cur_ops->poll_gp_state_full)) { 1302 pr_alert("%s: gp_poll_exp_full without primitives.\n", __func__); 1303 } 1304 if (gp_sync1 && cur_ops->sync) { 1305 synctype[nsynctypes++] = RTWS_SYNC; 1306 pr_info("%s: Testing normal GPs.\n", __func__); 1307 } else if (gp_sync && !cur_ops->sync) { 1308 pr_alert("%s: gp_sync without primitives.\n", __func__); 1309 } 1310 } 1311 1312 /* 1313 * Do the specified rcu_torture_writer() synchronous grace period, 1314 * while also testing out the polled APIs. Note well that the single-CPU 1315 * grace-period optimizations must be accounted for. 1316 */ 1317 static void do_rtws_sync(struct torture_random_state *trsp, void (*sync)(void)) 1318 { 1319 unsigned long cookie; 1320 struct rcu_gp_oldstate cookie_full; 1321 bool dopoll; 1322 bool dopoll_full; 1323 unsigned long r = torture_random(trsp); 1324 1325 dopoll = cur_ops->get_gp_state && cur_ops->poll_gp_state && !(r & 0x300); 1326 dopoll_full = cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full && !(r & 0xc00); 1327 if (dopoll || dopoll_full) 1328 cpus_read_lock(); 1329 if (dopoll) 1330 cookie = cur_ops->get_gp_state(); 1331 if (dopoll_full) 1332 cur_ops->get_gp_state_full(&cookie_full); 1333 if (cur_ops->poll_need_2gp && cur_ops->poll_need_2gp(dopoll, dopoll_full)) 1334 sync(); 1335 sync(); 1336 WARN_ONCE(dopoll && !cur_ops->poll_gp_state(cookie), 1337 "%s: Cookie check 3 failed %pS() online %*pbl.", 1338 __func__, sync, cpumask_pr_args(cpu_online_mask)); 1339 WARN_ONCE(dopoll_full && !cur_ops->poll_gp_state_full(&cookie_full), 1340 "%s: Cookie check 4 failed %pS() online %*pbl", 1341 __func__, sync, cpumask_pr_args(cpu_online_mask)); 1342 if (dopoll || dopoll_full) 1343 cpus_read_unlock(); 1344 } 1345 1346 /* 1347 * RCU torture writer kthread. Repeatedly substitutes a new structure 1348 * for that pointed to by rcu_torture_current, freeing the old structure 1349 * after a series of grace periods (the "pipeline"). 1350 */ 1351 static int 1352 rcu_torture_writer(void *arg) 1353 { 1354 bool boot_ended; 1355 bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal(); 1356 unsigned long cookie; 1357 struct rcu_gp_oldstate cookie_full; 1358 int expediting = 0; 1359 unsigned long gp_snap; 1360 unsigned long gp_snap1; 1361 struct rcu_gp_oldstate gp_snap_full; 1362 struct rcu_gp_oldstate gp_snap1_full; 1363 int i; 1364 int idx; 1365 int oldnice = task_nice(current); 1366 struct rcu_gp_oldstate rgo[NUM_ACTIVE_RCU_POLL_FULL_OLDSTATE]; 1367 struct rcu_torture *rp; 1368 struct rcu_torture *old_rp; 1369 static DEFINE_TORTURE_RANDOM(rand); 1370 bool stutter_waited; 1371 unsigned long ulo[NUM_ACTIVE_RCU_POLL_OLDSTATE]; 1372 1373 VERBOSE_TOROUT_STRING("rcu_torture_writer task started"); 1374 if (!can_expedite) 1375 pr_alert("%s" TORTURE_FLAG 1376 " GP expediting controlled from boot/sysfs for %s.\n", 1377 torture_type, cur_ops->name); 1378 if (WARN_ONCE(nsynctypes == 0, 1379 "%s: No update-side primitives.\n", __func__)) { 1380 /* 1381 * No updates primitives, so don't try updating. 1382 * The resulting test won't be testing much, hence the 1383 * above WARN_ONCE(). 1384 */ 1385 rcu_torture_writer_state = RTWS_STOPPING; 1386 torture_kthread_stopping("rcu_torture_writer"); 1387 return 0; 1388 } 1389 1390 do { 1391 rcu_torture_writer_state = RTWS_FIXED_DELAY; 1392 torture_hrtimeout_us(500, 1000, &rand); 1393 rp = rcu_torture_alloc(); 1394 if (rp == NULL) 1395 continue; 1396 rp->rtort_pipe_count = 0; 1397 rcu_torture_writer_state = RTWS_DELAY; 1398 udelay(torture_random(&rand) & 0x3ff); 1399 rcu_torture_writer_state = RTWS_REPLACE; 1400 old_rp = rcu_dereference_check(rcu_torture_current, 1401 current == writer_task); 1402 rp->rtort_mbtest = 1; 1403 rcu_assign_pointer(rcu_torture_current, rp); 1404 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */ 1405 if (old_rp) { 1406 i = old_rp->rtort_pipe_count; 1407 if (i > RCU_TORTURE_PIPE_LEN) 1408 i = RCU_TORTURE_PIPE_LEN; 1409 atomic_inc(&rcu_torture_wcount[i]); 1410 WRITE_ONCE(old_rp->rtort_pipe_count, 1411 old_rp->rtort_pipe_count + 1); 1412 1413 // Make sure readers block polled grace periods. 1414 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) { 1415 idx = cur_ops->readlock(); 1416 cookie = cur_ops->get_gp_state(); 1417 WARN_ONCE(cur_ops->poll_gp_state(cookie), 1418 "%s: Cookie check 1 failed %s(%d) %lu->%lu\n", 1419 __func__, 1420 rcu_torture_writer_state_getname(), 1421 rcu_torture_writer_state, 1422 cookie, cur_ops->get_gp_state()); 1423 if (cur_ops->get_gp_completed) { 1424 cookie = cur_ops->get_gp_completed(); 1425 WARN_ON_ONCE(!cur_ops->poll_gp_state(cookie)); 1426 } 1427 cur_ops->readunlock(idx); 1428 } 1429 if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full) { 1430 idx = cur_ops->readlock(); 1431 cur_ops->get_gp_state_full(&cookie_full); 1432 WARN_ONCE(cur_ops->poll_gp_state_full(&cookie_full), 1433 "%s: Cookie check 5 failed %s(%d) online %*pbl\n", 1434 __func__, 1435 rcu_torture_writer_state_getname(), 1436 rcu_torture_writer_state, 1437 cpumask_pr_args(cpu_online_mask)); 1438 if (cur_ops->get_gp_completed_full) { 1439 cur_ops->get_gp_completed_full(&cookie_full); 1440 WARN_ON_ONCE(!cur_ops->poll_gp_state_full(&cookie_full)); 1441 } 1442 cur_ops->readunlock(idx); 1443 } 1444 switch (synctype[torture_random(&rand) % nsynctypes]) { 1445 case RTWS_DEF_FREE: 1446 rcu_torture_writer_state = RTWS_DEF_FREE; 1447 cur_ops->deferred_free(old_rp); 1448 break; 1449 case RTWS_EXP_SYNC: 1450 rcu_torture_writer_state = RTWS_EXP_SYNC; 1451 do_rtws_sync(&rand, cur_ops->exp_sync); 1452 rcu_torture_pipe_update(old_rp); 1453 break; 1454 case RTWS_COND_GET: 1455 rcu_torture_writer_state = RTWS_COND_GET; 1456 gp_snap = cur_ops->get_gp_state(); 1457 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); 1458 rcu_torture_writer_state = RTWS_COND_SYNC; 1459 cur_ops->cond_sync(gp_snap); 1460 rcu_torture_pipe_update(old_rp); 1461 break; 1462 case RTWS_COND_GET_EXP: 1463 rcu_torture_writer_state = RTWS_COND_GET_EXP; 1464 gp_snap = cur_ops->get_gp_state_exp(); 1465 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); 1466 rcu_torture_writer_state = RTWS_COND_SYNC_EXP; 1467 cur_ops->cond_sync_exp(gp_snap); 1468 rcu_torture_pipe_update(old_rp); 1469 break; 1470 case RTWS_COND_GET_FULL: 1471 rcu_torture_writer_state = RTWS_COND_GET_FULL; 1472 cur_ops->get_gp_state_full(&gp_snap_full); 1473 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); 1474 rcu_torture_writer_state = RTWS_COND_SYNC_FULL; 1475 cur_ops->cond_sync_full(&gp_snap_full); 1476 rcu_torture_pipe_update(old_rp); 1477 break; 1478 case RTWS_COND_GET_EXP_FULL: 1479 rcu_torture_writer_state = RTWS_COND_GET_EXP_FULL; 1480 cur_ops->get_gp_state_full(&gp_snap_full); 1481 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); 1482 rcu_torture_writer_state = RTWS_COND_SYNC_EXP_FULL; 1483 cur_ops->cond_sync_exp_full(&gp_snap_full); 1484 rcu_torture_pipe_update(old_rp); 1485 break; 1486 case RTWS_POLL_GET: 1487 rcu_torture_writer_state = RTWS_POLL_GET; 1488 for (i = 0; i < ARRAY_SIZE(ulo); i++) 1489 ulo[i] = cur_ops->get_comp_state(); 1490 gp_snap = cur_ops->start_gp_poll(); 1491 rcu_torture_writer_state = RTWS_POLL_WAIT; 1492 while (!cur_ops->poll_gp_state(gp_snap)) { 1493 gp_snap1 = cur_ops->get_gp_state(); 1494 for (i = 0; i < ARRAY_SIZE(ulo); i++) 1495 if (cur_ops->poll_gp_state(ulo[i]) || 1496 cur_ops->same_gp_state(ulo[i], gp_snap1)) { 1497 ulo[i] = gp_snap1; 1498 break; 1499 } 1500 WARN_ON_ONCE(i >= ARRAY_SIZE(ulo)); 1501 torture_hrtimeout_jiffies(torture_random(&rand) % 16, 1502 &rand); 1503 } 1504 rcu_torture_pipe_update(old_rp); 1505 break; 1506 case RTWS_POLL_GET_FULL: 1507 rcu_torture_writer_state = RTWS_POLL_GET_FULL; 1508 for (i = 0; i < ARRAY_SIZE(rgo); i++) 1509 cur_ops->get_comp_state_full(&rgo[i]); 1510 cur_ops->start_gp_poll_full(&gp_snap_full); 1511 rcu_torture_writer_state = RTWS_POLL_WAIT_FULL; 1512 while (!cur_ops->poll_gp_state_full(&gp_snap_full)) { 1513 cur_ops->get_gp_state_full(&gp_snap1_full); 1514 for (i = 0; i < ARRAY_SIZE(rgo); i++) 1515 if (cur_ops->poll_gp_state_full(&rgo[i]) || 1516 cur_ops->same_gp_state_full(&rgo[i], 1517 &gp_snap1_full)) { 1518 rgo[i] = gp_snap1_full; 1519 break; 1520 } 1521 WARN_ON_ONCE(i >= ARRAY_SIZE(rgo)); 1522 torture_hrtimeout_jiffies(torture_random(&rand) % 16, 1523 &rand); 1524 } 1525 rcu_torture_pipe_update(old_rp); 1526 break; 1527 case RTWS_POLL_GET_EXP: 1528 rcu_torture_writer_state = RTWS_POLL_GET_EXP; 1529 gp_snap = cur_ops->start_gp_poll_exp(); 1530 rcu_torture_writer_state = RTWS_POLL_WAIT_EXP; 1531 while (!cur_ops->poll_gp_state_exp(gp_snap)) 1532 torture_hrtimeout_jiffies(torture_random(&rand) % 16, 1533 &rand); 1534 rcu_torture_pipe_update(old_rp); 1535 break; 1536 case RTWS_POLL_GET_EXP_FULL: 1537 rcu_torture_writer_state = RTWS_POLL_GET_EXP_FULL; 1538 cur_ops->start_gp_poll_exp_full(&gp_snap_full); 1539 rcu_torture_writer_state = RTWS_POLL_WAIT_EXP_FULL; 1540 while (!cur_ops->poll_gp_state_full(&gp_snap_full)) 1541 torture_hrtimeout_jiffies(torture_random(&rand) % 16, 1542 &rand); 1543 rcu_torture_pipe_update(old_rp); 1544 break; 1545 case RTWS_SYNC: 1546 rcu_torture_writer_state = RTWS_SYNC; 1547 do_rtws_sync(&rand, cur_ops->sync); 1548 rcu_torture_pipe_update(old_rp); 1549 break; 1550 default: 1551 WARN_ON_ONCE(1); 1552 break; 1553 } 1554 } 1555 WRITE_ONCE(rcu_torture_current_version, 1556 rcu_torture_current_version + 1); 1557 /* Cycle through nesting levels of rcu_expedite_gp() calls. */ 1558 if (can_expedite && 1559 !(torture_random(&rand) & 0xff & (!!expediting - 1))) { 1560 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited()); 1561 if (expediting >= 0) 1562 rcu_expedite_gp(); 1563 else 1564 rcu_unexpedite_gp(); 1565 if (++expediting > 3) 1566 expediting = -expediting; 1567 } else if (!can_expedite) { /* Disabled during boot, recheck. */ 1568 can_expedite = !rcu_gp_is_expedited() && 1569 !rcu_gp_is_normal(); 1570 } 1571 rcu_torture_writer_state = RTWS_STUTTER; 1572 boot_ended = rcu_inkernel_boot_has_ended(); 1573 stutter_waited = stutter_wait("rcu_torture_writer"); 1574 if (stutter_waited && 1575 !atomic_read(&rcu_fwd_cb_nodelay) && 1576 !cur_ops->slow_gps && 1577 !torture_must_stop() && 1578 boot_ended) 1579 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) 1580 if (list_empty(&rcu_tortures[i].rtort_free) && 1581 rcu_access_pointer(rcu_torture_current) != 1582 &rcu_tortures[i]) { 1583 tracing_off(); 1584 WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count); 1585 rcu_ftrace_dump(DUMP_ALL); 1586 } 1587 if (stutter_waited) 1588 sched_set_normal(current, oldnice); 1589 } while (!torture_must_stop()); 1590 rcu_torture_current = NULL; // Let stats task know that we are done. 1591 /* Reset expediting back to unexpedited. */ 1592 if (expediting > 0) 1593 expediting = -expediting; 1594 while (can_expedite && expediting++ < 0) 1595 rcu_unexpedite_gp(); 1596 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited()); 1597 if (!can_expedite) 1598 pr_alert("%s" TORTURE_FLAG 1599 " Dynamic grace-period expediting was disabled.\n", 1600 torture_type); 1601 rcu_torture_writer_state = RTWS_STOPPING; 1602 torture_kthread_stopping("rcu_torture_writer"); 1603 return 0; 1604 } 1605 1606 /* 1607 * RCU torture fake writer kthread. Repeatedly calls sync, with a random 1608 * delay between calls. 1609 */ 1610 static int 1611 rcu_torture_fakewriter(void *arg) 1612 { 1613 unsigned long gp_snap; 1614 struct rcu_gp_oldstate gp_snap_full; 1615 DEFINE_TORTURE_RANDOM(rand); 1616 1617 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started"); 1618 set_user_nice(current, MAX_NICE); 1619 1620 if (WARN_ONCE(nsynctypes == 0, 1621 "%s: No update-side primitives.\n", __func__)) { 1622 /* 1623 * No updates primitives, so don't try updating. 1624 * The resulting test won't be testing much, hence the 1625 * above WARN_ONCE(). 1626 */ 1627 torture_kthread_stopping("rcu_torture_fakewriter"); 1628 return 0; 1629 } 1630 1631 do { 1632 torture_hrtimeout_jiffies(torture_random(&rand) % 10, &rand); 1633 if (cur_ops->cb_barrier != NULL && 1634 torture_random(&rand) % (nfakewriters * 8) == 0) { 1635 cur_ops->cb_barrier(); 1636 } else { 1637 switch (synctype[torture_random(&rand) % nsynctypes]) { 1638 case RTWS_DEF_FREE: 1639 break; 1640 case RTWS_EXP_SYNC: 1641 cur_ops->exp_sync(); 1642 break; 1643 case RTWS_COND_GET: 1644 gp_snap = cur_ops->get_gp_state(); 1645 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); 1646 cur_ops->cond_sync(gp_snap); 1647 break; 1648 case RTWS_COND_GET_EXP: 1649 gp_snap = cur_ops->get_gp_state_exp(); 1650 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); 1651 cur_ops->cond_sync_exp(gp_snap); 1652 break; 1653 case RTWS_COND_GET_FULL: 1654 cur_ops->get_gp_state_full(&gp_snap_full); 1655 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); 1656 cur_ops->cond_sync_full(&gp_snap_full); 1657 break; 1658 case RTWS_COND_GET_EXP_FULL: 1659 cur_ops->get_gp_state_full(&gp_snap_full); 1660 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); 1661 cur_ops->cond_sync_exp_full(&gp_snap_full); 1662 break; 1663 case RTWS_POLL_GET: 1664 gp_snap = cur_ops->start_gp_poll(); 1665 while (!cur_ops->poll_gp_state(gp_snap)) { 1666 torture_hrtimeout_jiffies(torture_random(&rand) % 16, 1667 &rand); 1668 } 1669 break; 1670 case RTWS_POLL_GET_FULL: 1671 cur_ops->start_gp_poll_full(&gp_snap_full); 1672 while (!cur_ops->poll_gp_state_full(&gp_snap_full)) { 1673 torture_hrtimeout_jiffies(torture_random(&rand) % 16, 1674 &rand); 1675 } 1676 break; 1677 case RTWS_POLL_GET_EXP: 1678 gp_snap = cur_ops->start_gp_poll_exp(); 1679 while (!cur_ops->poll_gp_state_exp(gp_snap)) { 1680 torture_hrtimeout_jiffies(torture_random(&rand) % 16, 1681 &rand); 1682 } 1683 break; 1684 case RTWS_POLL_GET_EXP_FULL: 1685 cur_ops->start_gp_poll_exp_full(&gp_snap_full); 1686 while (!cur_ops->poll_gp_state_full(&gp_snap_full)) { 1687 torture_hrtimeout_jiffies(torture_random(&rand) % 16, 1688 &rand); 1689 } 1690 break; 1691 case RTWS_SYNC: 1692 cur_ops->sync(); 1693 break; 1694 default: 1695 WARN_ON_ONCE(1); 1696 break; 1697 } 1698 } 1699 stutter_wait("rcu_torture_fakewriter"); 1700 } while (!torture_must_stop()); 1701 1702 torture_kthread_stopping("rcu_torture_fakewriter"); 1703 return 0; 1704 } 1705 1706 static void rcu_torture_timer_cb(struct rcu_head *rhp) 1707 { 1708 kfree(rhp); 1709 } 1710 1711 // Set up and carry out testing of RCU's global memory ordering 1712 static void rcu_torture_reader_do_mbchk(long myid, struct rcu_torture *rtp, 1713 struct torture_random_state *trsp) 1714 { 1715 unsigned long loops; 1716 int noc = torture_num_online_cpus(); 1717 int rdrchked; 1718 int rdrchker; 1719 struct rcu_torture_reader_check *rtrcp; // Me. 1720 struct rcu_torture_reader_check *rtrcp_assigner; // Assigned us to do checking. 1721 struct rcu_torture_reader_check *rtrcp_chked; // Reader being checked. 1722 struct rcu_torture_reader_check *rtrcp_chker; // Reader doing checking when not me. 1723 1724 if (myid < 0) 1725 return; // Don't try this from timer handlers. 1726 1727 // Increment my counter. 1728 rtrcp = &rcu_torture_reader_mbchk[myid]; 1729 WRITE_ONCE(rtrcp->rtc_myloops, rtrcp->rtc_myloops + 1); 1730 1731 // Attempt to assign someone else some checking work. 1732 rdrchked = torture_random(trsp) % nrealreaders; 1733 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked]; 1734 rdrchker = torture_random(trsp) % nrealreaders; 1735 rtrcp_chker = &rcu_torture_reader_mbchk[rdrchker]; 1736 if (rdrchked != myid && rdrchked != rdrchker && noc >= rdrchked && noc >= rdrchker && 1737 smp_load_acquire(&rtrcp->rtc_chkrdr) < 0 && // Pairs with smp_store_release below. 1738 !READ_ONCE(rtp->rtort_chkp) && 1739 !smp_load_acquire(&rtrcp_chker->rtc_assigner)) { // Pairs with smp_store_release below. 1740 rtrcp->rtc_chkloops = READ_ONCE(rtrcp_chked->rtc_myloops); 1741 WARN_ON_ONCE(rtrcp->rtc_chkrdr >= 0); 1742 rtrcp->rtc_chkrdr = rdrchked; 1743 WARN_ON_ONCE(rtrcp->rtc_ready); // This gets set after the grace period ends. 1744 if (cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, NULL, rtrcp) || 1745 cmpxchg_relaxed(&rtp->rtort_chkp, NULL, rtrcp)) 1746 (void)cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, rtrcp, NULL); // Back out. 1747 } 1748 1749 // If assigned some completed work, do it! 1750 rtrcp_assigner = READ_ONCE(rtrcp->rtc_assigner); 1751 if (!rtrcp_assigner || !smp_load_acquire(&rtrcp_assigner->rtc_ready)) 1752 return; // No work or work not yet ready. 1753 rdrchked = rtrcp_assigner->rtc_chkrdr; 1754 if (WARN_ON_ONCE(rdrchked < 0)) 1755 return; 1756 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked]; 1757 loops = READ_ONCE(rtrcp_chked->rtc_myloops); 1758 atomic_inc(&n_rcu_torture_mbchk_tries); 1759 if (ULONG_CMP_LT(loops, rtrcp_assigner->rtc_chkloops)) 1760 atomic_inc(&n_rcu_torture_mbchk_fail); 1761 rtrcp_assigner->rtc_chkloops = loops + ULONG_MAX / 2; 1762 rtrcp_assigner->rtc_ready = 0; 1763 smp_store_release(&rtrcp->rtc_assigner, NULL); // Someone else can assign us work. 1764 smp_store_release(&rtrcp_assigner->rtc_chkrdr, -1); // Assigner can again assign. 1765 } 1766 1767 /* 1768 * Do one extension of an RCU read-side critical section using the 1769 * current reader state in readstate (set to zero for initial entry 1770 * to extended critical section), set the new state as specified by 1771 * newstate (set to zero for final exit from extended critical section), 1772 * and random-number-generator state in trsp. If this is neither the 1773 * beginning or end of the critical section and if there was actually a 1774 * change, do a ->read_delay(). 1775 */ 1776 static void rcutorture_one_extend(int *readstate, int newstate, 1777 struct torture_random_state *trsp, 1778 struct rt_read_seg *rtrsp) 1779 { 1780 unsigned long flags; 1781 int idxnew1 = -1; 1782 int idxnew2 = -1; 1783 int idxold1 = *readstate; 1784 int idxold2 = idxold1; 1785 int statesnew = ~*readstate & newstate; 1786 int statesold = *readstate & ~newstate; 1787 1788 WARN_ON_ONCE(idxold2 < 0); 1789 WARN_ON_ONCE((idxold2 >> RCUTORTURE_RDR_SHIFT_2) > 1); 1790 rtrsp->rt_readstate = newstate; 1791 1792 /* First, put new protection in place to avoid critical-section gap. */ 1793 if (statesnew & RCUTORTURE_RDR_BH) 1794 local_bh_disable(); 1795 if (statesnew & RCUTORTURE_RDR_RBH) 1796 rcu_read_lock_bh(); 1797 if (statesnew & RCUTORTURE_RDR_IRQ) 1798 local_irq_disable(); 1799 if (statesnew & RCUTORTURE_RDR_PREEMPT) 1800 preempt_disable(); 1801 if (statesnew & RCUTORTURE_RDR_SCHED) 1802 rcu_read_lock_sched(); 1803 if (statesnew & RCUTORTURE_RDR_RCU_1) 1804 idxnew1 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_1; 1805 if (statesnew & RCUTORTURE_RDR_RCU_2) 1806 idxnew2 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_2; 1807 1808 /* 1809 * Next, remove old protection, in decreasing order of strength 1810 * to avoid unlock paths that aren't safe in the stronger 1811 * context. Namely: BH can not be enabled with disabled interrupts. 1812 * Additionally PREEMPT_RT requires that BH is enabled in preemptible 1813 * context. 1814 */ 1815 if (statesold & RCUTORTURE_RDR_IRQ) 1816 local_irq_enable(); 1817 if (statesold & RCUTORTURE_RDR_PREEMPT) 1818 preempt_enable(); 1819 if (statesold & RCUTORTURE_RDR_SCHED) 1820 rcu_read_unlock_sched(); 1821 if (statesold & RCUTORTURE_RDR_BH) 1822 local_bh_enable(); 1823 if (statesold & RCUTORTURE_RDR_RBH) 1824 rcu_read_unlock_bh(); 1825 if (statesold & RCUTORTURE_RDR_RCU_2) { 1826 cur_ops->readunlock((idxold2 >> RCUTORTURE_RDR_SHIFT_2) & 0x1); 1827 WARN_ON_ONCE(idxnew2 != -1); 1828 idxold2 = 0; 1829 } 1830 if (statesold & RCUTORTURE_RDR_RCU_1) { 1831 bool lockit; 1832 1833 lockit = !cur_ops->no_pi_lock && !statesnew && !(torture_random(trsp) & 0xffff); 1834 if (lockit) 1835 raw_spin_lock_irqsave(¤t->pi_lock, flags); 1836 cur_ops->readunlock((idxold1 >> RCUTORTURE_RDR_SHIFT_1) & 0x1); 1837 WARN_ON_ONCE(idxnew1 != -1); 1838 idxold1 = 0; 1839 if (lockit) 1840 raw_spin_unlock_irqrestore(¤t->pi_lock, flags); 1841 } 1842 1843 /* Delay if neither beginning nor end and there was a change. */ 1844 if ((statesnew || statesold) && *readstate && newstate) 1845 cur_ops->read_delay(trsp, rtrsp); 1846 1847 /* Update the reader state. */ 1848 if (idxnew1 == -1) 1849 idxnew1 = idxold1 & RCUTORTURE_RDR_MASK_1; 1850 WARN_ON_ONCE(idxnew1 < 0); 1851 if (WARN_ON_ONCE((idxnew1 >> RCUTORTURE_RDR_SHIFT_1) > 1)) 1852 pr_info("Unexpected idxnew1 value of %#x\n", idxnew1); 1853 if (idxnew2 == -1) 1854 idxnew2 = idxold2 & RCUTORTURE_RDR_MASK_2; 1855 WARN_ON_ONCE(idxnew2 < 0); 1856 WARN_ON_ONCE((idxnew2 >> RCUTORTURE_RDR_SHIFT_2) > 1); 1857 *readstate = idxnew1 | idxnew2 | newstate; 1858 WARN_ON_ONCE(*readstate < 0); 1859 if (WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT_2) > 1)) 1860 pr_info("Unexpected idxnew2 value of %#x\n", idxnew2); 1861 } 1862 1863 /* Return the biggest extendables mask given current RCU and boot parameters. */ 1864 static int rcutorture_extend_mask_max(void) 1865 { 1866 int mask; 1867 1868 WARN_ON_ONCE(extendables & ~RCUTORTURE_MAX_EXTEND); 1869 mask = extendables & RCUTORTURE_MAX_EXTEND & cur_ops->extendables; 1870 mask = mask | RCUTORTURE_RDR_RCU_1 | RCUTORTURE_RDR_RCU_2; 1871 return mask; 1872 } 1873 1874 /* Return a random protection state mask, but with at least one bit set. */ 1875 static int 1876 rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp) 1877 { 1878 int mask = rcutorture_extend_mask_max(); 1879 unsigned long randmask1 = torture_random(trsp) >> 8; 1880 unsigned long randmask2 = randmask1 >> 3; 1881 unsigned long preempts = RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED; 1882 unsigned long preempts_irq = preempts | RCUTORTURE_RDR_IRQ; 1883 unsigned long bhs = RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH; 1884 1885 WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT_1); 1886 /* Mostly only one bit (need preemption!), sometimes lots of bits. */ 1887 if (!(randmask1 & 0x7)) 1888 mask = mask & randmask2; 1889 else 1890 mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS)); 1891 1892 // Can't have nested RCU reader without outer RCU reader. 1893 if (!(mask & RCUTORTURE_RDR_RCU_1) && (mask & RCUTORTURE_RDR_RCU_2)) { 1894 if (oldmask & RCUTORTURE_RDR_RCU_1) 1895 mask &= ~RCUTORTURE_RDR_RCU_2; 1896 else 1897 mask |= RCUTORTURE_RDR_RCU_1; 1898 } 1899 1900 /* 1901 * Can't enable bh w/irq disabled. 1902 */ 1903 if (mask & RCUTORTURE_RDR_IRQ) 1904 mask |= oldmask & bhs; 1905 1906 /* 1907 * Ideally these sequences would be detected in debug builds 1908 * (regardless of RT), but until then don't stop testing 1909 * them on non-RT. 1910 */ 1911 if (IS_ENABLED(CONFIG_PREEMPT_RT)) { 1912 /* Can't modify BH in atomic context */ 1913 if (oldmask & preempts_irq) 1914 mask &= ~bhs; 1915 if ((oldmask | mask) & preempts_irq) 1916 mask |= oldmask & bhs; 1917 } 1918 1919 return mask ?: RCUTORTURE_RDR_RCU_1; 1920 } 1921 1922 /* 1923 * Do a randomly selected number of extensions of an existing RCU read-side 1924 * critical section. 1925 */ 1926 static struct rt_read_seg * 1927 rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp, 1928 struct rt_read_seg *rtrsp) 1929 { 1930 int i; 1931 int j; 1932 int mask = rcutorture_extend_mask_max(); 1933 1934 WARN_ON_ONCE(!*readstate); /* -Existing- RCU read-side critsect! */ 1935 if (!((mask - 1) & mask)) 1936 return rtrsp; /* Current RCU reader not extendable. */ 1937 /* Bias towards larger numbers of loops. */ 1938 i = (torture_random(trsp) >> 3); 1939 i = ((i | (i >> 3)) & RCUTORTURE_RDR_MAX_LOOPS) + 1; 1940 for (j = 0; j < i; j++) { 1941 mask = rcutorture_extend_mask(*readstate, trsp); 1942 rcutorture_one_extend(readstate, mask, trsp, &rtrsp[j]); 1943 } 1944 return &rtrsp[j]; 1945 } 1946 1947 /* 1948 * Do one read-side critical section, returning false if there was 1949 * no data to read. Can be invoked both from process context and 1950 * from a timer handler. 1951 */ 1952 static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid) 1953 { 1954 bool checkpolling = !(torture_random(trsp) & 0xfff); 1955 unsigned long cookie; 1956 struct rcu_gp_oldstate cookie_full; 1957 int i; 1958 unsigned long started; 1959 unsigned long completed; 1960 int newstate; 1961 struct rcu_torture *p; 1962 int pipe_count; 1963 int readstate = 0; 1964 struct rt_read_seg rtseg[RCUTORTURE_RDR_MAX_SEGS] = { { 0 } }; 1965 struct rt_read_seg *rtrsp = &rtseg[0]; 1966 struct rt_read_seg *rtrsp1; 1967 unsigned long long ts; 1968 1969 WARN_ON_ONCE(!rcu_is_watching()); 1970 newstate = rcutorture_extend_mask(readstate, trsp); 1971 rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++); 1972 if (checkpolling) { 1973 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) 1974 cookie = cur_ops->get_gp_state(); 1975 if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full) 1976 cur_ops->get_gp_state_full(&cookie_full); 1977 } 1978 started = cur_ops->get_gp_seq(); 1979 ts = rcu_trace_clock_local(); 1980 p = rcu_dereference_check(rcu_torture_current, 1981 !cur_ops->readlock_held || cur_ops->readlock_held()); 1982 if (p == NULL) { 1983 /* Wait for rcu_torture_writer to get underway */ 1984 rcutorture_one_extend(&readstate, 0, trsp, rtrsp); 1985 return false; 1986 } 1987 if (p->rtort_mbtest == 0) 1988 atomic_inc(&n_rcu_torture_mberror); 1989 rcu_torture_reader_do_mbchk(myid, p, trsp); 1990 rtrsp = rcutorture_loop_extend(&readstate, trsp, rtrsp); 1991 preempt_disable(); 1992 pipe_count = READ_ONCE(p->rtort_pipe_count); 1993 if (pipe_count > RCU_TORTURE_PIPE_LEN) { 1994 /* Should not happen, but... */ 1995 pipe_count = RCU_TORTURE_PIPE_LEN; 1996 } 1997 completed = cur_ops->get_gp_seq(); 1998 if (pipe_count > 1) { 1999 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, 2000 ts, started, completed); 2001 rcu_ftrace_dump(DUMP_ALL); 2002 } 2003 __this_cpu_inc(rcu_torture_count[pipe_count]); 2004 completed = rcutorture_seq_diff(completed, started); 2005 if (completed > RCU_TORTURE_PIPE_LEN) { 2006 /* Should not happen, but... */ 2007 completed = RCU_TORTURE_PIPE_LEN; 2008 } 2009 __this_cpu_inc(rcu_torture_batch[completed]); 2010 preempt_enable(); 2011 if (checkpolling) { 2012 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) 2013 WARN_ONCE(cur_ops->poll_gp_state(cookie), 2014 "%s: Cookie check 2 failed %s(%d) %lu->%lu\n", 2015 __func__, 2016 rcu_torture_writer_state_getname(), 2017 rcu_torture_writer_state, 2018 cookie, cur_ops->get_gp_state()); 2019 if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full) 2020 WARN_ONCE(cur_ops->poll_gp_state_full(&cookie_full), 2021 "%s: Cookie check 6 failed %s(%d) online %*pbl\n", 2022 __func__, 2023 rcu_torture_writer_state_getname(), 2024 rcu_torture_writer_state, 2025 cpumask_pr_args(cpu_online_mask)); 2026 } 2027 rcutorture_one_extend(&readstate, 0, trsp, rtrsp); 2028 WARN_ON_ONCE(readstate); 2029 // This next splat is expected behavior if leakpointer, especially 2030 // for CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels. 2031 WARN_ON_ONCE(leakpointer && READ_ONCE(p->rtort_pipe_count) > 1); 2032 2033 /* If error or close call, record the sequence of reader protections. */ 2034 if ((pipe_count > 1 || completed > 1) && !xchg(&err_segs_recorded, 1)) { 2035 i = 0; 2036 for (rtrsp1 = &rtseg[0]; rtrsp1 < rtrsp; rtrsp1++) 2037 err_segs[i++] = *rtrsp1; 2038 rt_read_nsegs = i; 2039 } 2040 2041 return true; 2042 } 2043 2044 static DEFINE_TORTURE_RANDOM_PERCPU(rcu_torture_timer_rand); 2045 2046 /* 2047 * RCU torture reader from timer handler. Dereferences rcu_torture_current, 2048 * incrementing the corresponding element of the pipeline array. The 2049 * counter in the element should never be greater than 1, otherwise, the 2050 * RCU implementation is broken. 2051 */ 2052 static void rcu_torture_timer(struct timer_list *unused) 2053 { 2054 atomic_long_inc(&n_rcu_torture_timers); 2055 (void)rcu_torture_one_read(this_cpu_ptr(&rcu_torture_timer_rand), -1); 2056 2057 /* Test call_rcu() invocation from interrupt handler. */ 2058 if (cur_ops->call) { 2059 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT); 2060 2061 if (rhp) 2062 cur_ops->call(rhp, rcu_torture_timer_cb); 2063 } 2064 } 2065 2066 /* 2067 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current, 2068 * incrementing the corresponding element of the pipeline array. The 2069 * counter in the element should never be greater than 1, otherwise, the 2070 * RCU implementation is broken. 2071 */ 2072 static int 2073 rcu_torture_reader(void *arg) 2074 { 2075 unsigned long lastsleep = jiffies; 2076 long myid = (long)arg; 2077 int mynumonline = myid; 2078 DEFINE_TORTURE_RANDOM(rand); 2079 struct timer_list t; 2080 2081 VERBOSE_TOROUT_STRING("rcu_torture_reader task started"); 2082 set_user_nice(current, MAX_NICE); 2083 if (irqreader && cur_ops->irq_capable) 2084 timer_setup_on_stack(&t, rcu_torture_timer, 0); 2085 tick_dep_set_task(current, TICK_DEP_BIT_RCU); 2086 do { 2087 if (irqreader && cur_ops->irq_capable) { 2088 if (!timer_pending(&t)) 2089 mod_timer(&t, jiffies + 1); 2090 } 2091 if (!rcu_torture_one_read(&rand, myid) && !torture_must_stop()) 2092 schedule_timeout_interruptible(HZ); 2093 if (time_after(jiffies, lastsleep) && !torture_must_stop()) { 2094 torture_hrtimeout_us(500, 1000, &rand); 2095 lastsleep = jiffies + 10; 2096 } 2097 while (torture_num_online_cpus() < mynumonline && !torture_must_stop()) 2098 schedule_timeout_interruptible(HZ / 5); 2099 stutter_wait("rcu_torture_reader"); 2100 } while (!torture_must_stop()); 2101 if (irqreader && cur_ops->irq_capable) { 2102 del_timer_sync(&t); 2103 destroy_timer_on_stack(&t); 2104 } 2105 tick_dep_clear_task(current, TICK_DEP_BIT_RCU); 2106 torture_kthread_stopping("rcu_torture_reader"); 2107 return 0; 2108 } 2109 2110 /* 2111 * Randomly Toggle CPUs' callback-offload state. This uses hrtimers to 2112 * increase race probabilities and fuzzes the interval between toggling. 2113 */ 2114 static int rcu_nocb_toggle(void *arg) 2115 { 2116 int cpu; 2117 int maxcpu = -1; 2118 int oldnice = task_nice(current); 2119 long r; 2120 DEFINE_TORTURE_RANDOM(rand); 2121 ktime_t toggle_delay; 2122 unsigned long toggle_fuzz; 2123 ktime_t toggle_interval = ms_to_ktime(nocbs_toggle); 2124 2125 VERBOSE_TOROUT_STRING("rcu_nocb_toggle task started"); 2126 while (!rcu_inkernel_boot_has_ended()) 2127 schedule_timeout_interruptible(HZ / 10); 2128 for_each_online_cpu(cpu) 2129 maxcpu = cpu; 2130 WARN_ON(maxcpu < 0); 2131 if (toggle_interval > ULONG_MAX) 2132 toggle_fuzz = ULONG_MAX >> 3; 2133 else 2134 toggle_fuzz = toggle_interval >> 3; 2135 if (toggle_fuzz <= 0) 2136 toggle_fuzz = NSEC_PER_USEC; 2137 do { 2138 r = torture_random(&rand); 2139 cpu = (r >> 4) % (maxcpu + 1); 2140 if (r & 0x1) { 2141 rcu_nocb_cpu_offload(cpu); 2142 atomic_long_inc(&n_nocb_offload); 2143 } else { 2144 rcu_nocb_cpu_deoffload(cpu); 2145 atomic_long_inc(&n_nocb_deoffload); 2146 } 2147 toggle_delay = torture_random(&rand) % toggle_fuzz + toggle_interval; 2148 set_current_state(TASK_INTERRUPTIBLE); 2149 schedule_hrtimeout(&toggle_delay, HRTIMER_MODE_REL); 2150 if (stutter_wait("rcu_nocb_toggle")) 2151 sched_set_normal(current, oldnice); 2152 } while (!torture_must_stop()); 2153 torture_kthread_stopping("rcu_nocb_toggle"); 2154 return 0; 2155 } 2156 2157 /* 2158 * Print torture statistics. Caller must ensure that there is only 2159 * one call to this function at a given time!!! This is normally 2160 * accomplished by relying on the module system to only have one copy 2161 * of the module loaded, and then by giving the rcu_torture_stats 2162 * kthread full control (or the init/cleanup functions when rcu_torture_stats 2163 * thread is not running). 2164 */ 2165 static void 2166 rcu_torture_stats_print(void) 2167 { 2168 int cpu; 2169 int i; 2170 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; 2171 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; 2172 struct rcu_torture *rtcp; 2173 static unsigned long rtcv_snap = ULONG_MAX; 2174 static bool splatted; 2175 struct task_struct *wtp; 2176 2177 for_each_possible_cpu(cpu) { 2178 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 2179 pipesummary[i] += READ_ONCE(per_cpu(rcu_torture_count, cpu)[i]); 2180 batchsummary[i] += READ_ONCE(per_cpu(rcu_torture_batch, cpu)[i]); 2181 } 2182 } 2183 for (i = RCU_TORTURE_PIPE_LEN; i >= 0; i--) { 2184 if (pipesummary[i] != 0) 2185 break; 2186 } 2187 2188 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 2189 rtcp = rcu_access_pointer(rcu_torture_current); 2190 pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ", 2191 rtcp, 2192 rtcp && !rcu_stall_is_suppressed_at_boot() ? "ver" : "VER", 2193 rcu_torture_current_version, 2194 list_empty(&rcu_torture_freelist), 2195 atomic_read(&n_rcu_torture_alloc), 2196 atomic_read(&n_rcu_torture_alloc_fail), 2197 atomic_read(&n_rcu_torture_free)); 2198 pr_cont("rtmbe: %d rtmbkf: %d/%d rtbe: %ld rtbke: %ld ", 2199 atomic_read(&n_rcu_torture_mberror), 2200 atomic_read(&n_rcu_torture_mbchk_fail), atomic_read(&n_rcu_torture_mbchk_tries), 2201 n_rcu_torture_barrier_error, 2202 n_rcu_torture_boost_ktrerror); 2203 pr_cont("rtbf: %ld rtb: %ld nt: %ld ", 2204 n_rcu_torture_boost_failure, 2205 n_rcu_torture_boosts, 2206 atomic_long_read(&n_rcu_torture_timers)); 2207 torture_onoff_stats(); 2208 pr_cont("barrier: %ld/%ld:%ld ", 2209 data_race(n_barrier_successes), 2210 data_race(n_barrier_attempts), 2211 data_race(n_rcu_torture_barrier_error)); 2212 pr_cont("read-exits: %ld ", data_race(n_read_exits)); // Statistic. 2213 pr_cont("nocb-toggles: %ld:%ld\n", 2214 atomic_long_read(&n_nocb_offload), atomic_long_read(&n_nocb_deoffload)); 2215 2216 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 2217 if (atomic_read(&n_rcu_torture_mberror) || 2218 atomic_read(&n_rcu_torture_mbchk_fail) || 2219 n_rcu_torture_barrier_error || n_rcu_torture_boost_ktrerror || 2220 n_rcu_torture_boost_failure || i > 1) { 2221 pr_cont("%s", "!!! "); 2222 atomic_inc(&n_rcu_torture_error); 2223 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mberror)); 2224 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mbchk_fail)); 2225 WARN_ON_ONCE(n_rcu_torture_barrier_error); // rcu_barrier() 2226 WARN_ON_ONCE(n_rcu_torture_boost_ktrerror); // no boost kthread 2227 WARN_ON_ONCE(n_rcu_torture_boost_failure); // boost failed (TIMER_SOFTIRQ RT prio?) 2228 WARN_ON_ONCE(i > 1); // Too-short grace period 2229 } 2230 pr_cont("Reader Pipe: "); 2231 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 2232 pr_cont(" %ld", pipesummary[i]); 2233 pr_cont("\n"); 2234 2235 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 2236 pr_cont("Reader Batch: "); 2237 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 2238 pr_cont(" %ld", batchsummary[i]); 2239 pr_cont("\n"); 2240 2241 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 2242 pr_cont("Free-Block Circulation: "); 2243 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 2244 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i])); 2245 } 2246 pr_cont("\n"); 2247 2248 if (cur_ops->stats) 2249 cur_ops->stats(); 2250 if (rtcv_snap == rcu_torture_current_version && 2251 rcu_access_pointer(rcu_torture_current) && 2252 !rcu_stall_is_suppressed()) { 2253 int __maybe_unused flags = 0; 2254 unsigned long __maybe_unused gp_seq = 0; 2255 2256 rcutorture_get_gp_data(cur_ops->ttype, 2257 &flags, &gp_seq); 2258 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, 2259 &flags, &gp_seq); 2260 wtp = READ_ONCE(writer_task); 2261 pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#x cpu %d\n", 2262 rcu_torture_writer_state_getname(), 2263 rcu_torture_writer_state, gp_seq, flags, 2264 wtp == NULL ? ~0U : wtp->__state, 2265 wtp == NULL ? -1 : (int)task_cpu(wtp)); 2266 if (!splatted && wtp) { 2267 sched_show_task(wtp); 2268 splatted = true; 2269 } 2270 if (cur_ops->gp_kthread_dbg) 2271 cur_ops->gp_kthread_dbg(); 2272 rcu_ftrace_dump(DUMP_ALL); 2273 } 2274 rtcv_snap = rcu_torture_current_version; 2275 } 2276 2277 /* 2278 * Periodically prints torture statistics, if periodic statistics printing 2279 * was specified via the stat_interval module parameter. 2280 */ 2281 static int 2282 rcu_torture_stats(void *arg) 2283 { 2284 VERBOSE_TOROUT_STRING("rcu_torture_stats task started"); 2285 do { 2286 schedule_timeout_interruptible(stat_interval * HZ); 2287 rcu_torture_stats_print(); 2288 torture_shutdown_absorb("rcu_torture_stats"); 2289 } while (!torture_must_stop()); 2290 torture_kthread_stopping("rcu_torture_stats"); 2291 return 0; 2292 } 2293 2294 /* Test mem_dump_obj() and friends. */ 2295 static void rcu_torture_mem_dump_obj(void) 2296 { 2297 struct rcu_head *rhp; 2298 struct kmem_cache *kcp; 2299 static int z; 2300 2301 kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL); 2302 if (WARN_ON_ONCE(!kcp)) 2303 return; 2304 rhp = kmem_cache_alloc(kcp, GFP_KERNEL); 2305 if (WARN_ON_ONCE(!rhp)) { 2306 kmem_cache_destroy(kcp); 2307 return; 2308 } 2309 pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z); 2310 pr_alert("mem_dump_obj(ZERO_SIZE_PTR):"); 2311 mem_dump_obj(ZERO_SIZE_PTR); 2312 pr_alert("mem_dump_obj(NULL):"); 2313 mem_dump_obj(NULL); 2314 pr_alert("mem_dump_obj(%px):", &rhp); 2315 mem_dump_obj(&rhp); 2316 pr_alert("mem_dump_obj(%px):", rhp); 2317 mem_dump_obj(rhp); 2318 pr_alert("mem_dump_obj(%px):", &rhp->func); 2319 mem_dump_obj(&rhp->func); 2320 pr_alert("mem_dump_obj(%px):", &z); 2321 mem_dump_obj(&z); 2322 kmem_cache_free(kcp, rhp); 2323 kmem_cache_destroy(kcp); 2324 rhp = kmalloc(sizeof(*rhp), GFP_KERNEL); 2325 if (WARN_ON_ONCE(!rhp)) 2326 return; 2327 pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp); 2328 pr_alert("mem_dump_obj(kmalloc %px):", rhp); 2329 mem_dump_obj(rhp); 2330 pr_alert("mem_dump_obj(kmalloc %px):", &rhp->func); 2331 mem_dump_obj(&rhp->func); 2332 kfree(rhp); 2333 rhp = vmalloc(4096); 2334 if (WARN_ON_ONCE(!rhp)) 2335 return; 2336 pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp); 2337 pr_alert("mem_dump_obj(vmalloc %px):", rhp); 2338 mem_dump_obj(rhp); 2339 pr_alert("mem_dump_obj(vmalloc %px):", &rhp->func); 2340 mem_dump_obj(&rhp->func); 2341 vfree(rhp); 2342 } 2343 2344 static void 2345 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag) 2346 { 2347 pr_alert("%s" TORTURE_FLAG 2348 "--- %s: nreaders=%d nfakewriters=%d " 2349 "stat_interval=%d verbose=%d test_no_idle_hz=%d " 2350 "shuffle_interval=%d stutter=%d irqreader=%d " 2351 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d " 2352 "test_boost=%d/%d test_boost_interval=%d " 2353 "test_boost_duration=%d shutdown_secs=%d " 2354 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d " 2355 "stall_cpu_block=%d " 2356 "n_barrier_cbs=%d " 2357 "onoff_interval=%d onoff_holdoff=%d " 2358 "read_exit_delay=%d read_exit_burst=%d " 2359 "nocbs_nthreads=%d nocbs_toggle=%d " 2360 "test_nmis=%d\n", 2361 torture_type, tag, nrealreaders, nfakewriters, 2362 stat_interval, verbose, test_no_idle_hz, shuffle_interval, 2363 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter, 2364 test_boost, cur_ops->can_boost, 2365 test_boost_interval, test_boost_duration, shutdown_secs, 2366 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff, 2367 stall_cpu_block, 2368 n_barrier_cbs, 2369 onoff_interval, onoff_holdoff, 2370 read_exit_delay, read_exit_burst, 2371 nocbs_nthreads, nocbs_toggle, 2372 test_nmis); 2373 } 2374 2375 static int rcutorture_booster_cleanup(unsigned int cpu) 2376 { 2377 struct task_struct *t; 2378 2379 if (boost_tasks[cpu] == NULL) 2380 return 0; 2381 mutex_lock(&boost_mutex); 2382 t = boost_tasks[cpu]; 2383 boost_tasks[cpu] = NULL; 2384 rcu_torture_enable_rt_throttle(); 2385 mutex_unlock(&boost_mutex); 2386 2387 /* This must be outside of the mutex, otherwise deadlock! */ 2388 torture_stop_kthread(rcu_torture_boost, t); 2389 return 0; 2390 } 2391 2392 static int rcutorture_booster_init(unsigned int cpu) 2393 { 2394 int retval; 2395 2396 if (boost_tasks[cpu] != NULL) 2397 return 0; /* Already created, nothing more to do. */ 2398 2399 // Testing RCU priority boosting requires rcutorture do 2400 // some serious abuse. Counter this by running ksoftirqd 2401 // at higher priority. 2402 if (IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)) { 2403 struct sched_param sp; 2404 struct task_struct *t; 2405 2406 t = per_cpu(ksoftirqd, cpu); 2407 WARN_ON_ONCE(!t); 2408 sp.sched_priority = 2; 2409 sched_setscheduler_nocheck(t, SCHED_FIFO, &sp); 2410 } 2411 2412 /* Don't allow time recalculation while creating a new task. */ 2413 mutex_lock(&boost_mutex); 2414 rcu_torture_disable_rt_throttle(); 2415 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task"); 2416 boost_tasks[cpu] = kthread_run_on_cpu(rcu_torture_boost, NULL, 2417 cpu, "rcu_torture_boost_%u"); 2418 if (IS_ERR(boost_tasks[cpu])) { 2419 retval = PTR_ERR(boost_tasks[cpu]); 2420 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed"); 2421 n_rcu_torture_boost_ktrerror++; 2422 boost_tasks[cpu] = NULL; 2423 mutex_unlock(&boost_mutex); 2424 return retval; 2425 } 2426 mutex_unlock(&boost_mutex); 2427 return 0; 2428 } 2429 2430 /* 2431 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then 2432 * induces a CPU stall for the time specified by stall_cpu. 2433 */ 2434 static int rcu_torture_stall(void *args) 2435 { 2436 int idx; 2437 unsigned long stop_at; 2438 2439 VERBOSE_TOROUT_STRING("rcu_torture_stall task started"); 2440 if (stall_cpu_holdoff > 0) { 2441 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff"); 2442 schedule_timeout_interruptible(stall_cpu_holdoff * HZ); 2443 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff"); 2444 } 2445 if (!kthread_should_stop() && stall_gp_kthread > 0) { 2446 VERBOSE_TOROUT_STRING("rcu_torture_stall begin GP stall"); 2447 rcu_gp_set_torture_wait(stall_gp_kthread * HZ); 2448 for (idx = 0; idx < stall_gp_kthread + 2; idx++) { 2449 if (kthread_should_stop()) 2450 break; 2451 schedule_timeout_uninterruptible(HZ); 2452 } 2453 } 2454 if (!kthread_should_stop() && stall_cpu > 0) { 2455 VERBOSE_TOROUT_STRING("rcu_torture_stall begin CPU stall"); 2456 stop_at = ktime_get_seconds() + stall_cpu; 2457 /* RCU CPU stall is expected behavior in following code. */ 2458 idx = cur_ops->readlock(); 2459 if (stall_cpu_irqsoff) 2460 local_irq_disable(); 2461 else if (!stall_cpu_block) 2462 preempt_disable(); 2463 pr_alert("%s start on CPU %d.\n", 2464 __func__, raw_smp_processor_id()); 2465 while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(), 2466 stop_at)) 2467 if (stall_cpu_block) { 2468 #ifdef CONFIG_PREEMPTION 2469 preempt_schedule(); 2470 #else 2471 schedule_timeout_uninterruptible(HZ); 2472 #endif 2473 } else if (stall_no_softlockup) { 2474 touch_softlockup_watchdog(); 2475 } 2476 if (stall_cpu_irqsoff) 2477 local_irq_enable(); 2478 else if (!stall_cpu_block) 2479 preempt_enable(); 2480 cur_ops->readunlock(idx); 2481 } 2482 pr_alert("%s end.\n", __func__); 2483 torture_shutdown_absorb("rcu_torture_stall"); 2484 while (!kthread_should_stop()) 2485 schedule_timeout_interruptible(10 * HZ); 2486 return 0; 2487 } 2488 2489 /* Spawn CPU-stall kthread, if stall_cpu specified. */ 2490 static int __init rcu_torture_stall_init(void) 2491 { 2492 if (stall_cpu <= 0 && stall_gp_kthread <= 0) 2493 return 0; 2494 return torture_create_kthread(rcu_torture_stall, NULL, stall_task); 2495 } 2496 2497 /* State structure for forward-progress self-propagating RCU callback. */ 2498 struct fwd_cb_state { 2499 struct rcu_head rh; 2500 int stop; 2501 }; 2502 2503 /* 2504 * Forward-progress self-propagating RCU callback function. Because 2505 * callbacks run from softirq, this function is an implicit RCU read-side 2506 * critical section. 2507 */ 2508 static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp) 2509 { 2510 struct fwd_cb_state *fcsp = container_of(rhp, struct fwd_cb_state, rh); 2511 2512 if (READ_ONCE(fcsp->stop)) { 2513 WRITE_ONCE(fcsp->stop, 2); 2514 return; 2515 } 2516 cur_ops->call(&fcsp->rh, rcu_torture_fwd_prog_cb); 2517 } 2518 2519 /* State for continuous-flood RCU callbacks. */ 2520 struct rcu_fwd_cb { 2521 struct rcu_head rh; 2522 struct rcu_fwd_cb *rfc_next; 2523 struct rcu_fwd *rfc_rfp; 2524 int rfc_gps; 2525 }; 2526 2527 #define MAX_FWD_CB_JIFFIES (8 * HZ) /* Maximum CB test duration. */ 2528 #define MIN_FWD_CB_LAUNDERS 3 /* This many CB invocations to count. */ 2529 #define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */ 2530 #define FWD_CBS_HIST_DIV 10 /* Histogram buckets/second. */ 2531 #define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV)) 2532 2533 struct rcu_launder_hist { 2534 long n_launders; 2535 unsigned long launder_gp_seq; 2536 }; 2537 2538 struct rcu_fwd { 2539 spinlock_t rcu_fwd_lock; 2540 struct rcu_fwd_cb *rcu_fwd_cb_head; 2541 struct rcu_fwd_cb **rcu_fwd_cb_tail; 2542 long n_launders_cb; 2543 unsigned long rcu_fwd_startat; 2544 struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST]; 2545 unsigned long rcu_launder_gp_seq_start; 2546 int rcu_fwd_id; 2547 }; 2548 2549 static DEFINE_MUTEX(rcu_fwd_mutex); 2550 static struct rcu_fwd *rcu_fwds; 2551 static unsigned long rcu_fwd_seq; 2552 static atomic_long_t rcu_fwd_max_cbs; 2553 static bool rcu_fwd_emergency_stop; 2554 2555 static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp) 2556 { 2557 unsigned long gps; 2558 unsigned long gps_old; 2559 int i; 2560 int j; 2561 2562 for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--) 2563 if (rfp->n_launders_hist[i].n_launders > 0) 2564 break; 2565 pr_alert("%s: Callback-invocation histogram %d (duration %lu jiffies):", 2566 __func__, rfp->rcu_fwd_id, jiffies - rfp->rcu_fwd_startat); 2567 gps_old = rfp->rcu_launder_gp_seq_start; 2568 for (j = 0; j <= i; j++) { 2569 gps = rfp->n_launders_hist[j].launder_gp_seq; 2570 pr_cont(" %ds/%d: %ld:%ld", 2571 j + 1, FWD_CBS_HIST_DIV, 2572 rfp->n_launders_hist[j].n_launders, 2573 rcutorture_seq_diff(gps, gps_old)); 2574 gps_old = gps; 2575 } 2576 pr_cont("\n"); 2577 } 2578 2579 /* Callback function for continuous-flood RCU callbacks. */ 2580 static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp) 2581 { 2582 unsigned long flags; 2583 int i; 2584 struct rcu_fwd_cb *rfcp = container_of(rhp, struct rcu_fwd_cb, rh); 2585 struct rcu_fwd_cb **rfcpp; 2586 struct rcu_fwd *rfp = rfcp->rfc_rfp; 2587 2588 rfcp->rfc_next = NULL; 2589 rfcp->rfc_gps++; 2590 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags); 2591 rfcpp = rfp->rcu_fwd_cb_tail; 2592 rfp->rcu_fwd_cb_tail = &rfcp->rfc_next; 2593 WRITE_ONCE(*rfcpp, rfcp); 2594 WRITE_ONCE(rfp->n_launders_cb, rfp->n_launders_cb + 1); 2595 i = ((jiffies - rfp->rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV)); 2596 if (i >= ARRAY_SIZE(rfp->n_launders_hist)) 2597 i = ARRAY_SIZE(rfp->n_launders_hist) - 1; 2598 rfp->n_launders_hist[i].n_launders++; 2599 rfp->n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq(); 2600 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 2601 } 2602 2603 // Give the scheduler a chance, even on nohz_full CPUs. 2604 static void rcu_torture_fwd_prog_cond_resched(unsigned long iter) 2605 { 2606 if (IS_ENABLED(CONFIG_PREEMPTION) && IS_ENABLED(CONFIG_NO_HZ_FULL)) { 2607 // Real call_rcu() floods hit userspace, so emulate that. 2608 if (need_resched() || (iter & 0xfff)) 2609 schedule(); 2610 return; 2611 } 2612 // No userspace emulation: CB invocation throttles call_rcu() 2613 cond_resched(); 2614 } 2615 2616 /* 2617 * Free all callbacks on the rcu_fwd_cb_head list, either because the 2618 * test is over or because we hit an OOM event. 2619 */ 2620 static unsigned long rcu_torture_fwd_prog_cbfree(struct rcu_fwd *rfp) 2621 { 2622 unsigned long flags; 2623 unsigned long freed = 0; 2624 struct rcu_fwd_cb *rfcp; 2625 2626 for (;;) { 2627 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags); 2628 rfcp = rfp->rcu_fwd_cb_head; 2629 if (!rfcp) { 2630 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 2631 break; 2632 } 2633 rfp->rcu_fwd_cb_head = rfcp->rfc_next; 2634 if (!rfp->rcu_fwd_cb_head) 2635 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head; 2636 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 2637 kfree(rfcp); 2638 freed++; 2639 rcu_torture_fwd_prog_cond_resched(freed); 2640 if (tick_nohz_full_enabled()) { 2641 local_irq_save(flags); 2642 rcu_momentary_dyntick_idle(); 2643 local_irq_restore(flags); 2644 } 2645 } 2646 return freed; 2647 } 2648 2649 /* Carry out need_resched()/cond_resched() forward-progress testing. */ 2650 static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp, 2651 int *tested, int *tested_tries) 2652 { 2653 unsigned long cver; 2654 unsigned long dur; 2655 struct fwd_cb_state fcs; 2656 unsigned long gps; 2657 int idx; 2658 int sd; 2659 int sd4; 2660 bool selfpropcb = false; 2661 unsigned long stopat; 2662 static DEFINE_TORTURE_RANDOM(trs); 2663 2664 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id); 2665 if (!cur_ops->sync) 2666 return; // Cannot do need_resched() forward progress testing without ->sync. 2667 if (cur_ops->call && cur_ops->cb_barrier) { 2668 init_rcu_head_on_stack(&fcs.rh); 2669 selfpropcb = true; 2670 } 2671 2672 /* Tight loop containing cond_resched(). */ 2673 atomic_inc(&rcu_fwd_cb_nodelay); 2674 cur_ops->sync(); /* Later readers see above write. */ 2675 if (selfpropcb) { 2676 WRITE_ONCE(fcs.stop, 0); 2677 cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb); 2678 } 2679 cver = READ_ONCE(rcu_torture_current_version); 2680 gps = cur_ops->get_gp_seq(); 2681 sd = cur_ops->stall_dur() + 1; 2682 sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div; 2683 dur = sd4 + torture_random(&trs) % (sd - sd4); 2684 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies); 2685 stopat = rfp->rcu_fwd_startat + dur; 2686 while (time_before(jiffies, stopat) && 2687 !shutdown_time_arrived() && 2688 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 2689 idx = cur_ops->readlock(); 2690 udelay(10); 2691 cur_ops->readunlock(idx); 2692 if (!fwd_progress_need_resched || need_resched()) 2693 cond_resched(); 2694 } 2695 (*tested_tries)++; 2696 if (!time_before(jiffies, stopat) && 2697 !shutdown_time_arrived() && 2698 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 2699 (*tested)++; 2700 cver = READ_ONCE(rcu_torture_current_version) - cver; 2701 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps); 2702 WARN_ON(!cver && gps < 2); 2703 pr_alert("%s: %d Duration %ld cver %ld gps %ld\n", __func__, 2704 rfp->rcu_fwd_id, dur, cver, gps); 2705 } 2706 if (selfpropcb) { 2707 WRITE_ONCE(fcs.stop, 1); 2708 cur_ops->sync(); /* Wait for running CB to complete. */ 2709 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id); 2710 cur_ops->cb_barrier(); /* Wait for queued callbacks. */ 2711 } 2712 2713 if (selfpropcb) { 2714 WARN_ON(READ_ONCE(fcs.stop) != 2); 2715 destroy_rcu_head_on_stack(&fcs.rh); 2716 } 2717 schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */ 2718 atomic_dec(&rcu_fwd_cb_nodelay); 2719 } 2720 2721 /* Carry out call_rcu() forward-progress testing. */ 2722 static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp) 2723 { 2724 unsigned long cver; 2725 unsigned long flags; 2726 unsigned long gps; 2727 int i; 2728 long n_launders; 2729 long n_launders_cb_snap; 2730 long n_launders_sa; 2731 long n_max_cbs; 2732 long n_max_gps; 2733 struct rcu_fwd_cb *rfcp; 2734 struct rcu_fwd_cb *rfcpn; 2735 unsigned long stopat; 2736 unsigned long stoppedat; 2737 2738 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id); 2739 if (READ_ONCE(rcu_fwd_emergency_stop)) 2740 return; /* Get out of the way quickly, no GP wait! */ 2741 if (!cur_ops->call) 2742 return; /* Can't do call_rcu() fwd prog without ->call. */ 2743 2744 /* Loop continuously posting RCU callbacks. */ 2745 atomic_inc(&rcu_fwd_cb_nodelay); 2746 cur_ops->sync(); /* Later readers see above write. */ 2747 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies); 2748 stopat = rfp->rcu_fwd_startat + MAX_FWD_CB_JIFFIES; 2749 n_launders = 0; 2750 rfp->n_launders_cb = 0; // Hoist initialization for multi-kthread 2751 n_launders_sa = 0; 2752 n_max_cbs = 0; 2753 n_max_gps = 0; 2754 for (i = 0; i < ARRAY_SIZE(rfp->n_launders_hist); i++) 2755 rfp->n_launders_hist[i].n_launders = 0; 2756 cver = READ_ONCE(rcu_torture_current_version); 2757 gps = cur_ops->get_gp_seq(); 2758 rfp->rcu_launder_gp_seq_start = gps; 2759 tick_dep_set_task(current, TICK_DEP_BIT_RCU); 2760 while (time_before(jiffies, stopat) && 2761 !shutdown_time_arrived() && 2762 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 2763 rfcp = READ_ONCE(rfp->rcu_fwd_cb_head); 2764 rfcpn = NULL; 2765 if (rfcp) 2766 rfcpn = READ_ONCE(rfcp->rfc_next); 2767 if (rfcpn) { 2768 if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS && 2769 ++n_max_gps >= MIN_FWD_CBS_LAUNDERED) 2770 break; 2771 rfp->rcu_fwd_cb_head = rfcpn; 2772 n_launders++; 2773 n_launders_sa++; 2774 } else if (!cur_ops->cbflood_max || cur_ops->cbflood_max > n_max_cbs) { 2775 rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL); 2776 if (WARN_ON_ONCE(!rfcp)) { 2777 schedule_timeout_interruptible(1); 2778 continue; 2779 } 2780 n_max_cbs++; 2781 n_launders_sa = 0; 2782 rfcp->rfc_gps = 0; 2783 rfcp->rfc_rfp = rfp; 2784 } else { 2785 rfcp = NULL; 2786 } 2787 if (rfcp) 2788 cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr); 2789 rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs); 2790 if (tick_nohz_full_enabled()) { 2791 local_irq_save(flags); 2792 rcu_momentary_dyntick_idle(); 2793 local_irq_restore(flags); 2794 } 2795 } 2796 stoppedat = jiffies; 2797 n_launders_cb_snap = READ_ONCE(rfp->n_launders_cb); 2798 cver = READ_ONCE(rcu_torture_current_version) - cver; 2799 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps); 2800 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id); 2801 cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */ 2802 (void)rcu_torture_fwd_prog_cbfree(rfp); 2803 2804 if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) && 2805 !shutdown_time_arrived()) { 2806 WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED); 2807 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", 2808 __func__, 2809 stoppedat - rfp->rcu_fwd_startat, jiffies - stoppedat, 2810 n_launders + n_max_cbs - n_launders_cb_snap, 2811 n_launders, n_launders_sa, 2812 n_max_gps, n_max_cbs, cver, gps); 2813 atomic_long_add(n_max_cbs, &rcu_fwd_max_cbs); 2814 mutex_lock(&rcu_fwd_mutex); // Serialize histograms. 2815 rcu_torture_fwd_cb_hist(rfp); 2816 mutex_unlock(&rcu_fwd_mutex); 2817 } 2818 schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */ 2819 tick_dep_clear_task(current, TICK_DEP_BIT_RCU); 2820 atomic_dec(&rcu_fwd_cb_nodelay); 2821 } 2822 2823 2824 /* 2825 * OOM notifier, but this only prints diagnostic information for the 2826 * current forward-progress test. 2827 */ 2828 static int rcutorture_oom_notify(struct notifier_block *self, 2829 unsigned long notused, void *nfreed) 2830 { 2831 int i; 2832 long ncbs; 2833 struct rcu_fwd *rfp; 2834 2835 mutex_lock(&rcu_fwd_mutex); 2836 rfp = rcu_fwds; 2837 if (!rfp) { 2838 mutex_unlock(&rcu_fwd_mutex); 2839 return NOTIFY_OK; 2840 } 2841 WARN(1, "%s invoked upon OOM during forward-progress testing.\n", 2842 __func__); 2843 for (i = 0; i < fwd_progress; i++) { 2844 rcu_torture_fwd_cb_hist(&rfp[i]); 2845 rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp[i].rcu_fwd_startat)) / 2); 2846 } 2847 WRITE_ONCE(rcu_fwd_emergency_stop, true); 2848 smp_mb(); /* Emergency stop before free and wait to avoid hangs. */ 2849 ncbs = 0; 2850 for (i = 0; i < fwd_progress; i++) 2851 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]); 2852 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs); 2853 cur_ops->cb_barrier(); 2854 ncbs = 0; 2855 for (i = 0; i < fwd_progress; i++) 2856 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]); 2857 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs); 2858 cur_ops->cb_barrier(); 2859 ncbs = 0; 2860 for (i = 0; i < fwd_progress; i++) 2861 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]); 2862 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs); 2863 smp_mb(); /* Frees before return to avoid redoing OOM. */ 2864 (*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */ 2865 pr_info("%s returning after OOM processing.\n", __func__); 2866 mutex_unlock(&rcu_fwd_mutex); 2867 return NOTIFY_OK; 2868 } 2869 2870 static struct notifier_block rcutorture_oom_nb = { 2871 .notifier_call = rcutorture_oom_notify 2872 }; 2873 2874 /* Carry out grace-period forward-progress testing. */ 2875 static int rcu_torture_fwd_prog(void *args) 2876 { 2877 bool firsttime = true; 2878 long max_cbs; 2879 int oldnice = task_nice(current); 2880 unsigned long oldseq = READ_ONCE(rcu_fwd_seq); 2881 struct rcu_fwd *rfp = args; 2882 int tested = 0; 2883 int tested_tries = 0; 2884 2885 VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started"); 2886 rcu_bind_current_to_nocb(); 2887 if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST)) 2888 set_user_nice(current, MAX_NICE); 2889 do { 2890 if (!rfp->rcu_fwd_id) { 2891 schedule_timeout_interruptible(fwd_progress_holdoff * HZ); 2892 WRITE_ONCE(rcu_fwd_emergency_stop, false); 2893 if (!firsttime) { 2894 max_cbs = atomic_long_xchg(&rcu_fwd_max_cbs, 0); 2895 pr_alert("%s n_max_cbs: %ld\n", __func__, max_cbs); 2896 } 2897 firsttime = false; 2898 WRITE_ONCE(rcu_fwd_seq, rcu_fwd_seq + 1); 2899 } else { 2900 while (READ_ONCE(rcu_fwd_seq) == oldseq && !torture_must_stop()) 2901 schedule_timeout_interruptible(1); 2902 oldseq = READ_ONCE(rcu_fwd_seq); 2903 } 2904 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id); 2905 if (rcu_inkernel_boot_has_ended() && torture_num_online_cpus() > rfp->rcu_fwd_id) 2906 rcu_torture_fwd_prog_cr(rfp); 2907 if ((cur_ops->stall_dur && cur_ops->stall_dur() > 0) && 2908 (!IS_ENABLED(CONFIG_TINY_RCU) || 2909 (rcu_inkernel_boot_has_ended() && 2910 torture_num_online_cpus() > rfp->rcu_fwd_id))) 2911 rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries); 2912 2913 /* Avoid slow periods, better to test when busy. */ 2914 if (stutter_wait("rcu_torture_fwd_prog")) 2915 sched_set_normal(current, oldnice); 2916 } while (!torture_must_stop()); 2917 /* Short runs might not contain a valid forward-progress attempt. */ 2918 if (!rfp->rcu_fwd_id) { 2919 WARN_ON(!tested && tested_tries >= 5); 2920 pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries); 2921 } 2922 torture_kthread_stopping("rcu_torture_fwd_prog"); 2923 return 0; 2924 } 2925 2926 /* If forward-progress checking is requested and feasible, spawn the thread. */ 2927 static int __init rcu_torture_fwd_prog_init(void) 2928 { 2929 int i; 2930 int ret = 0; 2931 struct rcu_fwd *rfp; 2932 2933 if (!fwd_progress) 2934 return 0; /* Not requested, so don't do it. */ 2935 if (fwd_progress >= nr_cpu_ids) { 2936 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Limiting fwd_progress to # CPUs.\n"); 2937 fwd_progress = nr_cpu_ids; 2938 } else if (fwd_progress < 0) { 2939 fwd_progress = nr_cpu_ids; 2940 } 2941 if ((!cur_ops->sync && !cur_ops->call) || 2942 (!cur_ops->cbflood_max && (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0)) || 2943 cur_ops == &rcu_busted_ops) { 2944 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test"); 2945 fwd_progress = 0; 2946 return 0; 2947 } 2948 if (stall_cpu > 0) { 2949 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing"); 2950 fwd_progress = 0; 2951 if (IS_MODULE(CONFIG_RCU_TORTURE_TEST)) 2952 return -EINVAL; /* In module, can fail back to user. */ 2953 WARN_ON(1); /* Make sure rcutorture notices conflict. */ 2954 return 0; 2955 } 2956 if (fwd_progress_holdoff <= 0) 2957 fwd_progress_holdoff = 1; 2958 if (fwd_progress_div <= 0) 2959 fwd_progress_div = 4; 2960 rfp = kcalloc(fwd_progress, sizeof(*rfp), GFP_KERNEL); 2961 fwd_prog_tasks = kcalloc(fwd_progress, sizeof(*fwd_prog_tasks), GFP_KERNEL); 2962 if (!rfp || !fwd_prog_tasks) { 2963 kfree(rfp); 2964 kfree(fwd_prog_tasks); 2965 fwd_prog_tasks = NULL; 2966 fwd_progress = 0; 2967 return -ENOMEM; 2968 } 2969 for (i = 0; i < fwd_progress; i++) { 2970 spin_lock_init(&rfp[i].rcu_fwd_lock); 2971 rfp[i].rcu_fwd_cb_tail = &rfp[i].rcu_fwd_cb_head; 2972 rfp[i].rcu_fwd_id = i; 2973 } 2974 mutex_lock(&rcu_fwd_mutex); 2975 rcu_fwds = rfp; 2976 mutex_unlock(&rcu_fwd_mutex); 2977 register_oom_notifier(&rcutorture_oom_nb); 2978 for (i = 0; i < fwd_progress; i++) { 2979 ret = torture_create_kthread(rcu_torture_fwd_prog, &rcu_fwds[i], fwd_prog_tasks[i]); 2980 if (ret) { 2981 fwd_progress = i; 2982 return ret; 2983 } 2984 } 2985 return 0; 2986 } 2987 2988 static void rcu_torture_fwd_prog_cleanup(void) 2989 { 2990 int i; 2991 struct rcu_fwd *rfp; 2992 2993 if (!rcu_fwds || !fwd_prog_tasks) 2994 return; 2995 for (i = 0; i < fwd_progress; i++) 2996 torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_tasks[i]); 2997 unregister_oom_notifier(&rcutorture_oom_nb); 2998 mutex_lock(&rcu_fwd_mutex); 2999 rfp = rcu_fwds; 3000 rcu_fwds = NULL; 3001 mutex_unlock(&rcu_fwd_mutex); 3002 kfree(rfp); 3003 kfree(fwd_prog_tasks); 3004 fwd_prog_tasks = NULL; 3005 } 3006 3007 /* Callback function for RCU barrier testing. */ 3008 static void rcu_torture_barrier_cbf(struct rcu_head *rcu) 3009 { 3010 atomic_inc(&barrier_cbs_invoked); 3011 } 3012 3013 /* IPI handler to get callback posted on desired CPU, if online. */ 3014 static void rcu_torture_barrier1cb(void *rcu_void) 3015 { 3016 struct rcu_head *rhp = rcu_void; 3017 3018 cur_ops->call(rhp, rcu_torture_barrier_cbf); 3019 } 3020 3021 /* kthread function to register callbacks used to test RCU barriers. */ 3022 static int rcu_torture_barrier_cbs(void *arg) 3023 { 3024 long myid = (long)arg; 3025 bool lastphase = false; 3026 bool newphase; 3027 struct rcu_head rcu; 3028 3029 init_rcu_head_on_stack(&rcu); 3030 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started"); 3031 set_user_nice(current, MAX_NICE); 3032 do { 3033 wait_event(barrier_cbs_wq[myid], 3034 (newphase = 3035 smp_load_acquire(&barrier_phase)) != lastphase || 3036 torture_must_stop()); 3037 lastphase = newphase; 3038 if (torture_must_stop()) 3039 break; 3040 /* 3041 * The above smp_load_acquire() ensures barrier_phase load 3042 * is ordered before the following ->call(). 3043 */ 3044 if (smp_call_function_single(myid, rcu_torture_barrier1cb, 3045 &rcu, 1)) { 3046 // IPI failed, so use direct call from current CPU. 3047 cur_ops->call(&rcu, rcu_torture_barrier_cbf); 3048 } 3049 if (atomic_dec_and_test(&barrier_cbs_count)) 3050 wake_up(&barrier_wq); 3051 } while (!torture_must_stop()); 3052 if (cur_ops->cb_barrier != NULL) 3053 cur_ops->cb_barrier(); 3054 destroy_rcu_head_on_stack(&rcu); 3055 torture_kthread_stopping("rcu_torture_barrier_cbs"); 3056 return 0; 3057 } 3058 3059 /* kthread function to drive and coordinate RCU barrier testing. */ 3060 static int rcu_torture_barrier(void *arg) 3061 { 3062 int i; 3063 3064 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting"); 3065 do { 3066 atomic_set(&barrier_cbs_invoked, 0); 3067 atomic_set(&barrier_cbs_count, n_barrier_cbs); 3068 /* Ensure barrier_phase ordered after prior assignments. */ 3069 smp_store_release(&barrier_phase, !barrier_phase); 3070 for (i = 0; i < n_barrier_cbs; i++) 3071 wake_up(&barrier_cbs_wq[i]); 3072 wait_event(barrier_wq, 3073 atomic_read(&barrier_cbs_count) == 0 || 3074 torture_must_stop()); 3075 if (torture_must_stop()) 3076 break; 3077 n_barrier_attempts++; 3078 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */ 3079 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) { 3080 n_rcu_torture_barrier_error++; 3081 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n", 3082 atomic_read(&barrier_cbs_invoked), 3083 n_barrier_cbs); 3084 WARN_ON(1); 3085 // Wait manually for the remaining callbacks 3086 i = 0; 3087 do { 3088 if (WARN_ON(i++ > HZ)) 3089 i = INT_MIN; 3090 schedule_timeout_interruptible(1); 3091 cur_ops->cb_barrier(); 3092 } while (atomic_read(&barrier_cbs_invoked) != 3093 n_barrier_cbs && 3094 !torture_must_stop()); 3095 smp_mb(); // Can't trust ordering if broken. 3096 if (!torture_must_stop()) 3097 pr_err("Recovered: barrier_cbs_invoked = %d\n", 3098 atomic_read(&barrier_cbs_invoked)); 3099 } else { 3100 n_barrier_successes++; 3101 } 3102 schedule_timeout_interruptible(HZ / 10); 3103 } while (!torture_must_stop()); 3104 torture_kthread_stopping("rcu_torture_barrier"); 3105 return 0; 3106 } 3107 3108 /* Initialize RCU barrier testing. */ 3109 static int rcu_torture_barrier_init(void) 3110 { 3111 int i; 3112 int ret; 3113 3114 if (n_barrier_cbs <= 0) 3115 return 0; 3116 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) { 3117 pr_alert("%s" TORTURE_FLAG 3118 " Call or barrier ops missing for %s,\n", 3119 torture_type, cur_ops->name); 3120 pr_alert("%s" TORTURE_FLAG 3121 " RCU barrier testing omitted from run.\n", 3122 torture_type); 3123 return 0; 3124 } 3125 atomic_set(&barrier_cbs_count, 0); 3126 atomic_set(&barrier_cbs_invoked, 0); 3127 barrier_cbs_tasks = 3128 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]), 3129 GFP_KERNEL); 3130 barrier_cbs_wq = 3131 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL); 3132 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq) 3133 return -ENOMEM; 3134 for (i = 0; i < n_barrier_cbs; i++) { 3135 init_waitqueue_head(&barrier_cbs_wq[i]); 3136 ret = torture_create_kthread(rcu_torture_barrier_cbs, 3137 (void *)(long)i, 3138 barrier_cbs_tasks[i]); 3139 if (ret) 3140 return ret; 3141 } 3142 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task); 3143 } 3144 3145 /* Clean up after RCU barrier testing. */ 3146 static void rcu_torture_barrier_cleanup(void) 3147 { 3148 int i; 3149 3150 torture_stop_kthread(rcu_torture_barrier, barrier_task); 3151 if (barrier_cbs_tasks != NULL) { 3152 for (i = 0; i < n_barrier_cbs; i++) 3153 torture_stop_kthread(rcu_torture_barrier_cbs, 3154 barrier_cbs_tasks[i]); 3155 kfree(barrier_cbs_tasks); 3156 barrier_cbs_tasks = NULL; 3157 } 3158 if (barrier_cbs_wq != NULL) { 3159 kfree(barrier_cbs_wq); 3160 barrier_cbs_wq = NULL; 3161 } 3162 } 3163 3164 static bool rcu_torture_can_boost(void) 3165 { 3166 static int boost_warn_once; 3167 int prio; 3168 3169 if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2) 3170 return false; 3171 if (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state) 3172 return false; 3173 3174 prio = rcu_get_gp_kthreads_prio(); 3175 if (!prio) 3176 return false; 3177 3178 if (prio < 2) { 3179 if (boost_warn_once == 1) 3180 return false; 3181 3182 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); 3183 boost_warn_once = 1; 3184 return false; 3185 } 3186 3187 return true; 3188 } 3189 3190 static bool read_exit_child_stop; 3191 static bool read_exit_child_stopped; 3192 static wait_queue_head_t read_exit_wq; 3193 3194 // Child kthread which just does an rcutorture reader and exits. 3195 static int rcu_torture_read_exit_child(void *trsp_in) 3196 { 3197 struct torture_random_state *trsp = trsp_in; 3198 3199 set_user_nice(current, MAX_NICE); 3200 // Minimize time between reading and exiting. 3201 while (!kthread_should_stop()) 3202 schedule_timeout_uninterruptible(1); 3203 (void)rcu_torture_one_read(trsp, -1); 3204 return 0; 3205 } 3206 3207 // Parent kthread which creates and destroys read-exit child kthreads. 3208 static int rcu_torture_read_exit(void *unused) 3209 { 3210 bool errexit = false; 3211 int i; 3212 struct task_struct *tsp; 3213 DEFINE_TORTURE_RANDOM(trs); 3214 3215 // Allocate and initialize. 3216 set_user_nice(current, MAX_NICE); 3217 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of test"); 3218 3219 // Each pass through this loop does one read-exit episode. 3220 do { 3221 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of episode"); 3222 for (i = 0; i < read_exit_burst; i++) { 3223 if (READ_ONCE(read_exit_child_stop)) 3224 break; 3225 stutter_wait("rcu_torture_read_exit"); 3226 // Spawn child. 3227 tsp = kthread_run(rcu_torture_read_exit_child, 3228 &trs, "%s", "rcu_torture_read_exit_child"); 3229 if (IS_ERR(tsp)) { 3230 TOROUT_ERRSTRING("out of memory"); 3231 errexit = true; 3232 break; 3233 } 3234 cond_resched(); 3235 kthread_stop(tsp); 3236 n_read_exits++; 3237 } 3238 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: End of episode"); 3239 rcu_barrier(); // Wait for task_struct free, avoid OOM. 3240 i = 0; 3241 for (; !errexit && !READ_ONCE(read_exit_child_stop) && i < read_exit_delay; i++) 3242 schedule_timeout_uninterruptible(HZ); 3243 } while (!errexit && !READ_ONCE(read_exit_child_stop)); 3244 3245 // Clean up and exit. 3246 smp_store_release(&read_exit_child_stopped, true); // After reaping. 3247 smp_mb(); // Store before wakeup. 3248 wake_up(&read_exit_wq); 3249 while (!torture_must_stop()) 3250 schedule_timeout_uninterruptible(1); 3251 torture_kthread_stopping("rcu_torture_read_exit"); 3252 return 0; 3253 } 3254 3255 static int rcu_torture_read_exit_init(void) 3256 { 3257 if (read_exit_burst <= 0) 3258 return 0; 3259 init_waitqueue_head(&read_exit_wq); 3260 read_exit_child_stop = false; 3261 read_exit_child_stopped = false; 3262 return torture_create_kthread(rcu_torture_read_exit, NULL, 3263 read_exit_task); 3264 } 3265 3266 static void rcu_torture_read_exit_cleanup(void) 3267 { 3268 if (!read_exit_task) 3269 return; 3270 WRITE_ONCE(read_exit_child_stop, true); 3271 smp_mb(); // Above write before wait. 3272 wait_event(read_exit_wq, smp_load_acquire(&read_exit_child_stopped)); 3273 torture_stop_kthread(rcutorture_read_exit, read_exit_task); 3274 } 3275 3276 static void rcutorture_test_nmis(int n) 3277 { 3278 #if IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) 3279 int cpu; 3280 int dumpcpu; 3281 int i; 3282 3283 for (i = 0; i < n; i++) { 3284 preempt_disable(); 3285 cpu = smp_processor_id(); 3286 dumpcpu = cpu + 1; 3287 if (dumpcpu >= nr_cpu_ids) 3288 dumpcpu = 0; 3289 pr_alert("%s: CPU %d invoking dump_cpu_task(%d)\n", __func__, cpu, dumpcpu); 3290 dump_cpu_task(dumpcpu); 3291 preempt_enable(); 3292 schedule_timeout_uninterruptible(15 * HZ); 3293 } 3294 #else // #if IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) 3295 WARN_ONCE(n, "Non-zero rcutorture.test_nmis=%d permitted only when rcutorture is built in.\n", test_nmis); 3296 #endif // #else // #if IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) 3297 } 3298 3299 static enum cpuhp_state rcutor_hp; 3300 3301 static void 3302 rcu_torture_cleanup(void) 3303 { 3304 int firsttime; 3305 int flags = 0; 3306 unsigned long gp_seq = 0; 3307 int i; 3308 3309 if (torture_cleanup_begin()) { 3310 if (cur_ops->cb_barrier != NULL) { 3311 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier); 3312 cur_ops->cb_barrier(); 3313 } 3314 rcu_gp_slow_unregister(NULL); 3315 return; 3316 } 3317 if (!cur_ops) { 3318 torture_cleanup_end(); 3319 rcu_gp_slow_unregister(NULL); 3320 return; 3321 } 3322 3323 rcutorture_test_nmis(test_nmis); 3324 3325 if (cur_ops->gp_kthread_dbg) 3326 cur_ops->gp_kthread_dbg(); 3327 rcu_torture_read_exit_cleanup(); 3328 rcu_torture_barrier_cleanup(); 3329 rcu_torture_fwd_prog_cleanup(); 3330 torture_stop_kthread(rcu_torture_stall, stall_task); 3331 torture_stop_kthread(rcu_torture_writer, writer_task); 3332 3333 if (nocb_tasks) { 3334 for (i = 0; i < nrealnocbers; i++) 3335 torture_stop_kthread(rcu_nocb_toggle, nocb_tasks[i]); 3336 kfree(nocb_tasks); 3337 nocb_tasks = NULL; 3338 } 3339 3340 if (reader_tasks) { 3341 for (i = 0; i < nrealreaders; i++) 3342 torture_stop_kthread(rcu_torture_reader, 3343 reader_tasks[i]); 3344 kfree(reader_tasks); 3345 reader_tasks = NULL; 3346 } 3347 kfree(rcu_torture_reader_mbchk); 3348 rcu_torture_reader_mbchk = NULL; 3349 3350 if (fakewriter_tasks) { 3351 for (i = 0; i < nfakewriters; i++) 3352 torture_stop_kthread(rcu_torture_fakewriter, 3353 fakewriter_tasks[i]); 3354 kfree(fakewriter_tasks); 3355 fakewriter_tasks = NULL; 3356 } 3357 3358 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq); 3359 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq); 3360 pr_alert("%s: End-test grace-period state: g%ld f%#x total-gps=%ld\n", 3361 cur_ops->name, (long)gp_seq, flags, 3362 rcutorture_seq_diff(gp_seq, start_gp_seq)); 3363 torture_stop_kthread(rcu_torture_stats, stats_task); 3364 torture_stop_kthread(rcu_torture_fqs, fqs_task); 3365 if (rcu_torture_can_boost() && rcutor_hp >= 0) 3366 cpuhp_remove_state(rcutor_hp); 3367 3368 /* 3369 * Wait for all RCU callbacks to fire, then do torture-type-specific 3370 * cleanup operations. 3371 */ 3372 if (cur_ops->cb_barrier != NULL) { 3373 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier); 3374 cur_ops->cb_barrier(); 3375 } 3376 if (cur_ops->cleanup != NULL) 3377 cur_ops->cleanup(); 3378 3379 rcu_torture_mem_dump_obj(); 3380 3381 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */ 3382 3383 if (err_segs_recorded) { 3384 pr_alert("Failure/close-call rcutorture reader segments:\n"); 3385 if (rt_read_nsegs == 0) 3386 pr_alert("\t: No segments recorded!!!\n"); 3387 firsttime = 1; 3388 for (i = 0; i < rt_read_nsegs; i++) { 3389 pr_alert("\t%d: %#x ", i, err_segs[i].rt_readstate); 3390 if (err_segs[i].rt_delay_jiffies != 0) { 3391 pr_cont("%s%ldjiffies", firsttime ? "" : "+", 3392 err_segs[i].rt_delay_jiffies); 3393 firsttime = 0; 3394 } 3395 if (err_segs[i].rt_delay_ms != 0) { 3396 pr_cont("%s%ldms", firsttime ? "" : "+", 3397 err_segs[i].rt_delay_ms); 3398 firsttime = 0; 3399 } 3400 if (err_segs[i].rt_delay_us != 0) { 3401 pr_cont("%s%ldus", firsttime ? "" : "+", 3402 err_segs[i].rt_delay_us); 3403 firsttime = 0; 3404 } 3405 pr_cont("%s\n", 3406 err_segs[i].rt_preempted ? "preempted" : ""); 3407 3408 } 3409 } 3410 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error) 3411 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE"); 3412 else if (torture_onoff_failures()) 3413 rcu_torture_print_module_parms(cur_ops, 3414 "End of test: RCU_HOTPLUG"); 3415 else 3416 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS"); 3417 torture_cleanup_end(); 3418 rcu_gp_slow_unregister(&rcu_fwd_cb_nodelay); 3419 } 3420 3421 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD 3422 static void rcu_torture_leak_cb(struct rcu_head *rhp) 3423 { 3424 } 3425 3426 static void rcu_torture_err_cb(struct rcu_head *rhp) 3427 { 3428 /* 3429 * This -might- happen due to race conditions, but is unlikely. 3430 * The scenario that leads to this happening is that the 3431 * first of the pair of duplicate callbacks is queued, 3432 * someone else starts a grace period that includes that 3433 * callback, then the second of the pair must wait for the 3434 * next grace period. Unlikely, but can happen. If it 3435 * does happen, the debug-objects subsystem won't have splatted. 3436 */ 3437 pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME); 3438 } 3439 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 3440 3441 /* 3442 * Verify that double-free causes debug-objects to complain, but only 3443 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test 3444 * cannot be carried out. 3445 */ 3446 static void rcu_test_debug_objects(void) 3447 { 3448 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD 3449 struct rcu_head rh1; 3450 struct rcu_head rh2; 3451 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_KERNEL); 3452 3453 init_rcu_head_on_stack(&rh1); 3454 init_rcu_head_on_stack(&rh2); 3455 pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME); 3456 3457 /* Try to queue the rh2 pair of callbacks for the same grace period. */ 3458 preempt_disable(); /* Prevent preemption from interrupting test. */ 3459 rcu_read_lock(); /* Make it impossible to finish a grace period. */ 3460 call_rcu_hurry(&rh1, rcu_torture_leak_cb); /* Start grace period. */ 3461 local_irq_disable(); /* Make it harder to start a new grace period. */ 3462 call_rcu_hurry(&rh2, rcu_torture_leak_cb); 3463 call_rcu_hurry(&rh2, rcu_torture_err_cb); /* Duplicate callback. */ 3464 if (rhp) { 3465 call_rcu_hurry(rhp, rcu_torture_leak_cb); 3466 call_rcu_hurry(rhp, rcu_torture_err_cb); /* Another duplicate callback. */ 3467 } 3468 local_irq_enable(); 3469 rcu_read_unlock(); 3470 preempt_enable(); 3471 3472 /* Wait for them all to get done so we can safely return. */ 3473 rcu_barrier(); 3474 pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME); 3475 destroy_rcu_head_on_stack(&rh1); 3476 destroy_rcu_head_on_stack(&rh2); 3477 kfree(rhp); 3478 #else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 3479 pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME); 3480 #endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 3481 } 3482 3483 static void rcutorture_sync(void) 3484 { 3485 static unsigned long n; 3486 3487 if (cur_ops->sync && !(++n & 0xfff)) 3488 cur_ops->sync(); 3489 } 3490 3491 static DEFINE_MUTEX(mut0); 3492 static DEFINE_MUTEX(mut1); 3493 static DEFINE_MUTEX(mut2); 3494 static DEFINE_MUTEX(mut3); 3495 static DEFINE_MUTEX(mut4); 3496 static DEFINE_MUTEX(mut5); 3497 static DEFINE_MUTEX(mut6); 3498 static DEFINE_MUTEX(mut7); 3499 static DEFINE_MUTEX(mut8); 3500 static DEFINE_MUTEX(mut9); 3501 3502 static DECLARE_RWSEM(rwsem0); 3503 static DECLARE_RWSEM(rwsem1); 3504 static DECLARE_RWSEM(rwsem2); 3505 static DECLARE_RWSEM(rwsem3); 3506 static DECLARE_RWSEM(rwsem4); 3507 static DECLARE_RWSEM(rwsem5); 3508 static DECLARE_RWSEM(rwsem6); 3509 static DECLARE_RWSEM(rwsem7); 3510 static DECLARE_RWSEM(rwsem8); 3511 static DECLARE_RWSEM(rwsem9); 3512 3513 DEFINE_STATIC_SRCU(srcu0); 3514 DEFINE_STATIC_SRCU(srcu1); 3515 DEFINE_STATIC_SRCU(srcu2); 3516 DEFINE_STATIC_SRCU(srcu3); 3517 DEFINE_STATIC_SRCU(srcu4); 3518 DEFINE_STATIC_SRCU(srcu5); 3519 DEFINE_STATIC_SRCU(srcu6); 3520 DEFINE_STATIC_SRCU(srcu7); 3521 DEFINE_STATIC_SRCU(srcu8); 3522 DEFINE_STATIC_SRCU(srcu9); 3523 3524 static int srcu_lockdep_next(const char *f, const char *fl, const char *fs, const char *fu, int i, 3525 int cyclelen, int deadlock) 3526 { 3527 int j = i + 1; 3528 3529 if (j >= cyclelen) 3530 j = deadlock ? 0 : -1; 3531 if (j >= 0) 3532 pr_info("%s: %s(%d), %s(%d), %s(%d)\n", f, fl, i, fs, j, fu, i); 3533 else 3534 pr_info("%s: %s(%d), %s(%d)\n", f, fl, i, fu, i); 3535 return j; 3536 } 3537 3538 // Test lockdep on SRCU-based deadlock scenarios. 3539 static void rcu_torture_init_srcu_lockdep(void) 3540 { 3541 int cyclelen; 3542 int deadlock; 3543 bool err = false; 3544 int i; 3545 int j; 3546 int idx; 3547 struct mutex *muts[] = { &mut0, &mut1, &mut2, &mut3, &mut4, 3548 &mut5, &mut6, &mut7, &mut8, &mut9 }; 3549 struct rw_semaphore *rwsems[] = { &rwsem0, &rwsem1, &rwsem2, &rwsem3, &rwsem4, 3550 &rwsem5, &rwsem6, &rwsem7, &rwsem8, &rwsem9 }; 3551 struct srcu_struct *srcus[] = { &srcu0, &srcu1, &srcu2, &srcu3, &srcu4, 3552 &srcu5, &srcu6, &srcu7, &srcu8, &srcu9 }; 3553 int testtype; 3554 3555 if (!test_srcu_lockdep) 3556 return; 3557 3558 deadlock = test_srcu_lockdep / 1000; 3559 testtype = (test_srcu_lockdep / 10) % 100; 3560 cyclelen = test_srcu_lockdep % 10; 3561 WARN_ON_ONCE(ARRAY_SIZE(muts) != ARRAY_SIZE(srcus)); 3562 if (WARN_ONCE(deadlock != !!deadlock, 3563 "%s: test_srcu_lockdep=%d and deadlock digit %d must be zero or one.\n", 3564 __func__, test_srcu_lockdep, deadlock)) 3565 err = true; 3566 if (WARN_ONCE(cyclelen <= 0, 3567 "%s: test_srcu_lockdep=%d and cycle-length digit %d must be greater than zero.\n", 3568 __func__, test_srcu_lockdep, cyclelen)) 3569 err = true; 3570 if (err) 3571 goto err_out; 3572 3573 if (testtype == 0) { 3574 pr_info("%s: test_srcu_lockdep = %05d: SRCU %d-way %sdeadlock.\n", 3575 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-"); 3576 if (deadlock && cyclelen == 1) 3577 pr_info("%s: Expect hang.\n", __func__); 3578 for (i = 0; i < cyclelen; i++) { 3579 j = srcu_lockdep_next(__func__, "srcu_read_lock", "synchronize_srcu", 3580 "srcu_read_unlock", i, cyclelen, deadlock); 3581 idx = srcu_read_lock(srcus[i]); 3582 if (j >= 0) 3583 synchronize_srcu(srcus[j]); 3584 srcu_read_unlock(srcus[i], idx); 3585 } 3586 return; 3587 } 3588 3589 if (testtype == 1) { 3590 pr_info("%s: test_srcu_lockdep = %05d: SRCU/mutex %d-way %sdeadlock.\n", 3591 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-"); 3592 for (i = 0; i < cyclelen; i++) { 3593 pr_info("%s: srcu_read_lock(%d), mutex_lock(%d), mutex_unlock(%d), srcu_read_unlock(%d)\n", 3594 __func__, i, i, i, i); 3595 idx = srcu_read_lock(srcus[i]); 3596 mutex_lock(muts[i]); 3597 mutex_unlock(muts[i]); 3598 srcu_read_unlock(srcus[i], idx); 3599 3600 j = srcu_lockdep_next(__func__, "mutex_lock", "synchronize_srcu", 3601 "mutex_unlock", i, cyclelen, deadlock); 3602 mutex_lock(muts[i]); 3603 if (j >= 0) 3604 synchronize_srcu(srcus[j]); 3605 mutex_unlock(muts[i]); 3606 } 3607 return; 3608 } 3609 3610 if (testtype == 2) { 3611 pr_info("%s: test_srcu_lockdep = %05d: SRCU/rwsem %d-way %sdeadlock.\n", 3612 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-"); 3613 for (i = 0; i < cyclelen; i++) { 3614 pr_info("%s: srcu_read_lock(%d), down_read(%d), up_read(%d), srcu_read_unlock(%d)\n", 3615 __func__, i, i, i, i); 3616 idx = srcu_read_lock(srcus[i]); 3617 down_read(rwsems[i]); 3618 up_read(rwsems[i]); 3619 srcu_read_unlock(srcus[i], idx); 3620 3621 j = srcu_lockdep_next(__func__, "down_write", "synchronize_srcu", 3622 "up_write", i, cyclelen, deadlock); 3623 down_write(rwsems[i]); 3624 if (j >= 0) 3625 synchronize_srcu(srcus[j]); 3626 up_write(rwsems[i]); 3627 } 3628 return; 3629 } 3630 3631 #ifdef CONFIG_TASKS_TRACE_RCU 3632 if (testtype == 3) { 3633 pr_info("%s: test_srcu_lockdep = %05d: SRCU and Tasks Trace RCU %d-way %sdeadlock.\n", 3634 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-"); 3635 if (deadlock && cyclelen == 1) 3636 pr_info("%s: Expect hang.\n", __func__); 3637 for (i = 0; i < cyclelen; i++) { 3638 char *fl = i == 0 ? "rcu_read_lock_trace" : "srcu_read_lock"; 3639 char *fs = i == cyclelen - 1 ? "synchronize_rcu_tasks_trace" 3640 : "synchronize_srcu"; 3641 char *fu = i == 0 ? "rcu_read_unlock_trace" : "srcu_read_unlock"; 3642 3643 j = srcu_lockdep_next(__func__, fl, fs, fu, i, cyclelen, deadlock); 3644 if (i == 0) 3645 rcu_read_lock_trace(); 3646 else 3647 idx = srcu_read_lock(srcus[i]); 3648 if (j >= 0) { 3649 if (i == cyclelen - 1) 3650 synchronize_rcu_tasks_trace(); 3651 else 3652 synchronize_srcu(srcus[j]); 3653 } 3654 if (i == 0) 3655 rcu_read_unlock_trace(); 3656 else 3657 srcu_read_unlock(srcus[i], idx); 3658 } 3659 return; 3660 } 3661 #endif // #ifdef CONFIG_TASKS_TRACE_RCU 3662 3663 err_out: 3664 pr_info("%s: test_srcu_lockdep = %05d does nothing.\n", __func__, test_srcu_lockdep); 3665 pr_info("%s: test_srcu_lockdep = DNNL.\n", __func__); 3666 pr_info("%s: D: Deadlock if nonzero.\n", __func__); 3667 pr_info("%s: NN: Test number, 0=SRCU, 1=SRCU/mutex, 2=SRCU/rwsem, 3=SRCU/Tasks Trace RCU.\n", __func__); 3668 pr_info("%s: L: Cycle length.\n", __func__); 3669 if (!IS_ENABLED(CONFIG_TASKS_TRACE_RCU)) 3670 pr_info("%s: NN=3 disallowed because kernel is built with CONFIG_TASKS_TRACE_RCU=n\n", __func__); 3671 } 3672 3673 static int __init 3674 rcu_torture_init(void) 3675 { 3676 long i; 3677 int cpu; 3678 int firsterr = 0; 3679 int flags = 0; 3680 unsigned long gp_seq = 0; 3681 static struct rcu_torture_ops *torture_ops[] = { 3682 &rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops, &busted_srcud_ops, 3683 TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS 3684 &trivial_ops, 3685 }; 3686 3687 if (!torture_init_begin(torture_type, verbose)) 3688 return -EBUSY; 3689 3690 /* Process args and tell the world that the torturer is on the job. */ 3691 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) { 3692 cur_ops = torture_ops[i]; 3693 if (strcmp(torture_type, cur_ops->name) == 0) 3694 break; 3695 } 3696 if (i == ARRAY_SIZE(torture_ops)) { 3697 pr_alert("rcu-torture: invalid torture type: \"%s\"\n", 3698 torture_type); 3699 pr_alert("rcu-torture types:"); 3700 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) 3701 pr_cont(" %s", torture_ops[i]->name); 3702 pr_cont("\n"); 3703 firsterr = -EINVAL; 3704 cur_ops = NULL; 3705 goto unwind; 3706 } 3707 if (cur_ops->fqs == NULL && fqs_duration != 0) { 3708 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n"); 3709 fqs_duration = 0; 3710 } 3711 if (nocbs_nthreads != 0 && (cur_ops != &rcu_ops || 3712 !IS_ENABLED(CONFIG_RCU_NOCB_CPU))) { 3713 pr_alert("rcu-torture types: %s and CONFIG_RCU_NOCB_CPU=%d, nocb toggle disabled.\n", 3714 cur_ops->name, IS_ENABLED(CONFIG_RCU_NOCB_CPU)); 3715 nocbs_nthreads = 0; 3716 } 3717 if (cur_ops->init) 3718 cur_ops->init(); 3719 3720 rcu_torture_init_srcu_lockdep(); 3721 3722 if (nreaders >= 0) { 3723 nrealreaders = nreaders; 3724 } else { 3725 nrealreaders = num_online_cpus() - 2 - nreaders; 3726 if (nrealreaders <= 0) 3727 nrealreaders = 1; 3728 } 3729 rcu_torture_print_module_parms(cur_ops, "Start of test"); 3730 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq); 3731 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq); 3732 start_gp_seq = gp_seq; 3733 pr_alert("%s: Start-test grace-period state: g%ld f%#x\n", 3734 cur_ops->name, (long)gp_seq, flags); 3735 3736 /* Set up the freelist. */ 3737 3738 INIT_LIST_HEAD(&rcu_torture_freelist); 3739 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) { 3740 rcu_tortures[i].rtort_mbtest = 0; 3741 list_add_tail(&rcu_tortures[i].rtort_free, 3742 &rcu_torture_freelist); 3743 } 3744 3745 /* Initialize the statistics so that each run gets its own numbers. */ 3746 3747 rcu_torture_current = NULL; 3748 rcu_torture_current_version = 0; 3749 atomic_set(&n_rcu_torture_alloc, 0); 3750 atomic_set(&n_rcu_torture_alloc_fail, 0); 3751 atomic_set(&n_rcu_torture_free, 0); 3752 atomic_set(&n_rcu_torture_mberror, 0); 3753 atomic_set(&n_rcu_torture_mbchk_fail, 0); 3754 atomic_set(&n_rcu_torture_mbchk_tries, 0); 3755 atomic_set(&n_rcu_torture_error, 0); 3756 n_rcu_torture_barrier_error = 0; 3757 n_rcu_torture_boost_ktrerror = 0; 3758 n_rcu_torture_boost_failure = 0; 3759 n_rcu_torture_boosts = 0; 3760 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 3761 atomic_set(&rcu_torture_wcount[i], 0); 3762 for_each_possible_cpu(cpu) { 3763 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 3764 per_cpu(rcu_torture_count, cpu)[i] = 0; 3765 per_cpu(rcu_torture_batch, cpu)[i] = 0; 3766 } 3767 } 3768 err_segs_recorded = 0; 3769 rt_read_nsegs = 0; 3770 3771 /* Start up the kthreads. */ 3772 3773 rcu_torture_write_types(); 3774 firsterr = torture_create_kthread(rcu_torture_writer, NULL, 3775 writer_task); 3776 if (torture_init_error(firsterr)) 3777 goto unwind; 3778 if (nfakewriters > 0) { 3779 fakewriter_tasks = kcalloc(nfakewriters, 3780 sizeof(fakewriter_tasks[0]), 3781 GFP_KERNEL); 3782 if (fakewriter_tasks == NULL) { 3783 TOROUT_ERRSTRING("out of memory"); 3784 firsterr = -ENOMEM; 3785 goto unwind; 3786 } 3787 } 3788 for (i = 0; i < nfakewriters; i++) { 3789 firsterr = torture_create_kthread(rcu_torture_fakewriter, 3790 NULL, fakewriter_tasks[i]); 3791 if (torture_init_error(firsterr)) 3792 goto unwind; 3793 } 3794 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]), 3795 GFP_KERNEL); 3796 rcu_torture_reader_mbchk = kcalloc(nrealreaders, sizeof(*rcu_torture_reader_mbchk), 3797 GFP_KERNEL); 3798 if (!reader_tasks || !rcu_torture_reader_mbchk) { 3799 TOROUT_ERRSTRING("out of memory"); 3800 firsterr = -ENOMEM; 3801 goto unwind; 3802 } 3803 for (i = 0; i < nrealreaders; i++) { 3804 rcu_torture_reader_mbchk[i].rtc_chkrdr = -1; 3805 firsterr = torture_create_kthread(rcu_torture_reader, (void *)i, 3806 reader_tasks[i]); 3807 if (torture_init_error(firsterr)) 3808 goto unwind; 3809 } 3810 nrealnocbers = nocbs_nthreads; 3811 if (WARN_ON(nrealnocbers < 0)) 3812 nrealnocbers = 1; 3813 if (WARN_ON(nocbs_toggle < 0)) 3814 nocbs_toggle = HZ; 3815 if (nrealnocbers > 0) { 3816 nocb_tasks = kcalloc(nrealnocbers, sizeof(nocb_tasks[0]), GFP_KERNEL); 3817 if (nocb_tasks == NULL) { 3818 TOROUT_ERRSTRING("out of memory"); 3819 firsterr = -ENOMEM; 3820 goto unwind; 3821 } 3822 } else { 3823 nocb_tasks = NULL; 3824 } 3825 for (i = 0; i < nrealnocbers; i++) { 3826 firsterr = torture_create_kthread(rcu_nocb_toggle, NULL, nocb_tasks[i]); 3827 if (torture_init_error(firsterr)) 3828 goto unwind; 3829 } 3830 if (stat_interval > 0) { 3831 firsterr = torture_create_kthread(rcu_torture_stats, NULL, 3832 stats_task); 3833 if (torture_init_error(firsterr)) 3834 goto unwind; 3835 } 3836 if (test_no_idle_hz && shuffle_interval > 0) { 3837 firsterr = torture_shuffle_init(shuffle_interval * HZ); 3838 if (torture_init_error(firsterr)) 3839 goto unwind; 3840 } 3841 if (stutter < 0) 3842 stutter = 0; 3843 if (stutter) { 3844 int t; 3845 3846 t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ; 3847 firsterr = torture_stutter_init(stutter * HZ, t); 3848 if (torture_init_error(firsterr)) 3849 goto unwind; 3850 } 3851 if (fqs_duration < 0) 3852 fqs_duration = 0; 3853 if (fqs_duration) { 3854 /* Create the fqs thread */ 3855 firsterr = torture_create_kthread(rcu_torture_fqs, NULL, 3856 fqs_task); 3857 if (torture_init_error(firsterr)) 3858 goto unwind; 3859 } 3860 if (test_boost_interval < 1) 3861 test_boost_interval = 1; 3862 if (test_boost_duration < 2) 3863 test_boost_duration = 2; 3864 if (rcu_torture_can_boost()) { 3865 3866 boost_starttime = jiffies + test_boost_interval * HZ; 3867 3868 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE", 3869 rcutorture_booster_init, 3870 rcutorture_booster_cleanup); 3871 rcutor_hp = firsterr; 3872 if (torture_init_error(firsterr)) 3873 goto unwind; 3874 } 3875 shutdown_jiffies = jiffies + shutdown_secs * HZ; 3876 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup); 3877 if (torture_init_error(firsterr)) 3878 goto unwind; 3879 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval, 3880 rcutorture_sync); 3881 if (torture_init_error(firsterr)) 3882 goto unwind; 3883 firsterr = rcu_torture_stall_init(); 3884 if (torture_init_error(firsterr)) 3885 goto unwind; 3886 firsterr = rcu_torture_fwd_prog_init(); 3887 if (torture_init_error(firsterr)) 3888 goto unwind; 3889 firsterr = rcu_torture_barrier_init(); 3890 if (torture_init_error(firsterr)) 3891 goto unwind; 3892 firsterr = rcu_torture_read_exit_init(); 3893 if (torture_init_error(firsterr)) 3894 goto unwind; 3895 if (object_debug) 3896 rcu_test_debug_objects(); 3897 torture_init_end(); 3898 rcu_gp_slow_register(&rcu_fwd_cb_nodelay); 3899 return 0; 3900 3901 unwind: 3902 torture_init_end(); 3903 rcu_torture_cleanup(); 3904 if (shutdown_secs) { 3905 WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST)); 3906 kernel_power_off(); 3907 } 3908 return firsterr; 3909 } 3910 3911 module_init(rcu_torture_init); 3912 module_exit(rcu_torture_cleanup); 3913