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 rcu_torture_writer_state_getname(void)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 rcu_trace_clock_local(void)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 */ rcu_trace_clock_local(void)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 */ shutdown_time_arrived(void)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 * rcu_torture_alloc(void)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 rcu_torture_free(struct rcu_torture * p)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 torture_readlock_not_held(void)398 static int torture_readlock_not_held(void) 399 { 400 return rcu_read_lock_bh_held() || rcu_read_lock_sched_held(); 401 } 402 rcu_torture_read_lock(void)403 static int rcu_torture_read_lock(void) 404 { 405 rcu_read_lock(); 406 return 0; 407 } 408 409 static void rcu_read_delay(struct torture_random_state * rrsp,struct rt_read_seg * rtrsp)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 rcu_torture_read_unlock(int idx)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 rcu_torture_pipe_update_one(struct rcu_torture * rp)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 rcu_torture_pipe_update(struct rcu_torture * old_rp)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 rcu_torture_cb(struct rcu_head * p)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 rcu_no_completed(void)511 static unsigned long rcu_no_completed(void) 512 { 513 return 0; 514 } 515 rcu_torture_deferred_free(struct rcu_torture * p)516 static void rcu_torture_deferred_free(struct rcu_torture *p) 517 { 518 call_rcu_hurry(&p->rtort_rcu, rcu_torture_cb); 519 } 520 rcu_sync_torture_init(void)521 static void rcu_sync_torture_init(void) 522 { 523 INIT_LIST_HEAD(&rcu_torture_removed); 524 } 525 rcu_poll_need_2gp(bool poll,bool poll_full)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 */ rcu_busted_torture_deferred_free(struct rcu_torture * p)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 synchronize_rcu_busted(void)589 static void synchronize_rcu_busted(void) 590 { 591 /* This is a deliberate bug for testing purposes only! */ 592 } 593 594 static void call_rcu_busted(struct rcu_head * head,rcu_callback_t func)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 srcu_torture_read_lock(void)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 srcu_read_delay(struct torture_random_state * rrsp,struct rt_read_seg * rtrsp)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 srcu_torture_read_unlock(int idx)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 torture_srcu_read_lock_held(void)664 static int torture_srcu_read_lock_held(void) 665 { 666 return srcu_read_lock_held(srcu_ctlp); 667 } 668 srcu_torture_completed(void)669 static unsigned long srcu_torture_completed(void) 670 { 671 return srcu_batches_completed(srcu_ctlp); 672 } 673 srcu_torture_deferred_free(struct rcu_torture * rp)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 srcu_torture_synchronize(void)679 static void srcu_torture_synchronize(void) 680 { 681 synchronize_srcu(srcu_ctlp); 682 } 683 srcu_torture_get_gp_state(void)684 static unsigned long srcu_torture_get_gp_state(void) 685 { 686 return get_state_synchronize_srcu(srcu_ctlp); 687 } 688 srcu_torture_start_gp_poll(void)689 static unsigned long srcu_torture_start_gp_poll(void) 690 { 691 return start_poll_synchronize_srcu(srcu_ctlp); 692 } 693 srcu_torture_poll_gp_state(unsigned long oldstate)694 static bool srcu_torture_poll_gp_state(unsigned long oldstate) 695 { 696 return poll_state_synchronize_srcu(srcu_ctlp, oldstate); 697 } 698 srcu_torture_call(struct rcu_head * head,rcu_callback_t func)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 srcu_torture_barrier(void)705 static void srcu_torture_barrier(void) 706 { 707 srcu_barrier(srcu_ctlp); 708 } 709 srcu_torture_stats(void)710 static void srcu_torture_stats(void) 711 { 712 srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG); 713 } 714 srcu_torture_synchronize_expedited(void)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 srcu_torture_init(void)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 srcu_torture_cleanup(void)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 synchronize_rcu_trivial(void)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 rcu_torture_read_lock_trivial(void)818 static int rcu_torture_read_lock_trivial(void) 819 { 820 preempt_disable(); 821 return 0; 822 } 823 rcu_torture_read_unlock_trivial(int idx)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 tasks_torture_read_lock(void)851 static int tasks_torture_read_lock(void) 852 { 853 return 0; 854 } 855 tasks_torture_read_unlock(int idx)856 static void tasks_torture_read_unlock(int idx) 857 { 858 } 859 rcu_tasks_torture_deferred_free(struct rcu_torture * p)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 synchronize_rcu_mult_test(void)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 rcu_tasks_rude_torture_deferred_free(struct rcu_torture * p)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 tasks_tracing_torture_read_lock(void)945 static int tasks_tracing_torture_read_lock(void) 946 { 947 rcu_read_lock_trace(); 948 return 0; 949 } 950 tasks_tracing_torture_read_unlock(int idx)951 static void tasks_tracing_torture_read_unlock(int idx) 952 { 953 rcu_read_unlock_trace(); 954 } 955 rcu_tasks_tracing_torture_deferred_free(struct rcu_torture * p)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 rcutorture_seq_diff(unsigned long new,unsigned long old)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 rcu_torture_disable_rt_throttle(void)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 rcu_torture_enable_rt_throttle(void)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 rcu_torture_boost_failed(unsigned long gp_state,unsigned long * start)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 rcu_torture_boost(void * arg)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 rcu_torture_fqs(void * arg)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 */ rcu_torture_write_types(void)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 */ do_rtws_sync(struct torture_random_state * trsp,void (* sync)(void))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 rcu_torture_writer(void * arg)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 show_rcu_gp_kthreads(); 1585 WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count); 1586 rcu_ftrace_dump(DUMP_ALL); 1587 } 1588 if (stutter_waited) 1589 sched_set_normal(current, oldnice); 1590 } while (!torture_must_stop()); 1591 rcu_torture_current = NULL; // Let stats task know that we are done. 1592 /* Reset expediting back to unexpedited. */ 1593 if (expediting > 0) 1594 expediting = -expediting; 1595 while (can_expedite && expediting++ < 0) 1596 rcu_unexpedite_gp(); 1597 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited()); 1598 if (!can_expedite) 1599 pr_alert("%s" TORTURE_FLAG 1600 " Dynamic grace-period expediting was disabled.\n", 1601 torture_type); 1602 rcu_torture_writer_state = RTWS_STOPPING; 1603 torture_kthread_stopping("rcu_torture_writer"); 1604 return 0; 1605 } 1606 1607 /* 1608 * RCU torture fake writer kthread. Repeatedly calls sync, with a random 1609 * delay between calls. 1610 */ 1611 static int rcu_torture_fakewriter(void * arg)1612 rcu_torture_fakewriter(void *arg) 1613 { 1614 unsigned long gp_snap; 1615 struct rcu_gp_oldstate gp_snap_full; 1616 DEFINE_TORTURE_RANDOM(rand); 1617 1618 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started"); 1619 set_user_nice(current, MAX_NICE); 1620 1621 if (WARN_ONCE(nsynctypes == 0, 1622 "%s: No update-side primitives.\n", __func__)) { 1623 /* 1624 * No updates primitives, so don't try updating. 1625 * The resulting test won't be testing much, hence the 1626 * above WARN_ONCE(). 1627 */ 1628 torture_kthread_stopping("rcu_torture_fakewriter"); 1629 return 0; 1630 } 1631 1632 do { 1633 torture_hrtimeout_jiffies(torture_random(&rand) % 10, &rand); 1634 if (cur_ops->cb_barrier != NULL && 1635 torture_random(&rand) % (nfakewriters * 8) == 0) { 1636 cur_ops->cb_barrier(); 1637 } else { 1638 switch (synctype[torture_random(&rand) % nsynctypes]) { 1639 case RTWS_DEF_FREE: 1640 break; 1641 case RTWS_EXP_SYNC: 1642 cur_ops->exp_sync(); 1643 break; 1644 case RTWS_COND_GET: 1645 gp_snap = cur_ops->get_gp_state(); 1646 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); 1647 cur_ops->cond_sync(gp_snap); 1648 break; 1649 case RTWS_COND_GET_EXP: 1650 gp_snap = cur_ops->get_gp_state_exp(); 1651 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); 1652 cur_ops->cond_sync_exp(gp_snap); 1653 break; 1654 case RTWS_COND_GET_FULL: 1655 cur_ops->get_gp_state_full(&gp_snap_full); 1656 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); 1657 cur_ops->cond_sync_full(&gp_snap_full); 1658 break; 1659 case RTWS_COND_GET_EXP_FULL: 1660 cur_ops->get_gp_state_full(&gp_snap_full); 1661 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand); 1662 cur_ops->cond_sync_exp_full(&gp_snap_full); 1663 break; 1664 case RTWS_POLL_GET: 1665 gp_snap = cur_ops->start_gp_poll(); 1666 while (!cur_ops->poll_gp_state(gp_snap)) { 1667 torture_hrtimeout_jiffies(torture_random(&rand) % 16, 1668 &rand); 1669 } 1670 break; 1671 case RTWS_POLL_GET_FULL: 1672 cur_ops->start_gp_poll_full(&gp_snap_full); 1673 while (!cur_ops->poll_gp_state_full(&gp_snap_full)) { 1674 torture_hrtimeout_jiffies(torture_random(&rand) % 16, 1675 &rand); 1676 } 1677 break; 1678 case RTWS_POLL_GET_EXP: 1679 gp_snap = cur_ops->start_gp_poll_exp(); 1680 while (!cur_ops->poll_gp_state_exp(gp_snap)) { 1681 torture_hrtimeout_jiffies(torture_random(&rand) % 16, 1682 &rand); 1683 } 1684 break; 1685 case RTWS_POLL_GET_EXP_FULL: 1686 cur_ops->start_gp_poll_exp_full(&gp_snap_full); 1687 while (!cur_ops->poll_gp_state_full(&gp_snap_full)) { 1688 torture_hrtimeout_jiffies(torture_random(&rand) % 16, 1689 &rand); 1690 } 1691 break; 1692 case RTWS_SYNC: 1693 cur_ops->sync(); 1694 break; 1695 default: 1696 WARN_ON_ONCE(1); 1697 break; 1698 } 1699 } 1700 stutter_wait("rcu_torture_fakewriter"); 1701 } while (!torture_must_stop()); 1702 1703 torture_kthread_stopping("rcu_torture_fakewriter"); 1704 return 0; 1705 } 1706 rcu_torture_timer_cb(struct rcu_head * rhp)1707 static void rcu_torture_timer_cb(struct rcu_head *rhp) 1708 { 1709 kfree(rhp); 1710 } 1711 1712 // Set up and carry out testing of RCU's global memory ordering rcu_torture_reader_do_mbchk(long myid,struct rcu_torture * rtp,struct torture_random_state * trsp)1713 static void rcu_torture_reader_do_mbchk(long myid, struct rcu_torture *rtp, 1714 struct torture_random_state *trsp) 1715 { 1716 unsigned long loops; 1717 int noc = torture_num_online_cpus(); 1718 int rdrchked; 1719 int rdrchker; 1720 struct rcu_torture_reader_check *rtrcp; // Me. 1721 struct rcu_torture_reader_check *rtrcp_assigner; // Assigned us to do checking. 1722 struct rcu_torture_reader_check *rtrcp_chked; // Reader being checked. 1723 struct rcu_torture_reader_check *rtrcp_chker; // Reader doing checking when not me. 1724 1725 if (myid < 0) 1726 return; // Don't try this from timer handlers. 1727 1728 // Increment my counter. 1729 rtrcp = &rcu_torture_reader_mbchk[myid]; 1730 WRITE_ONCE(rtrcp->rtc_myloops, rtrcp->rtc_myloops + 1); 1731 1732 // Attempt to assign someone else some checking work. 1733 rdrchked = torture_random(trsp) % nrealreaders; 1734 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked]; 1735 rdrchker = torture_random(trsp) % nrealreaders; 1736 rtrcp_chker = &rcu_torture_reader_mbchk[rdrchker]; 1737 if (rdrchked != myid && rdrchked != rdrchker && noc >= rdrchked && noc >= rdrchker && 1738 smp_load_acquire(&rtrcp->rtc_chkrdr) < 0 && // Pairs with smp_store_release below. 1739 !READ_ONCE(rtp->rtort_chkp) && 1740 !smp_load_acquire(&rtrcp_chker->rtc_assigner)) { // Pairs with smp_store_release below. 1741 rtrcp->rtc_chkloops = READ_ONCE(rtrcp_chked->rtc_myloops); 1742 WARN_ON_ONCE(rtrcp->rtc_chkrdr >= 0); 1743 rtrcp->rtc_chkrdr = rdrchked; 1744 WARN_ON_ONCE(rtrcp->rtc_ready); // This gets set after the grace period ends. 1745 if (cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, NULL, rtrcp) || 1746 cmpxchg_relaxed(&rtp->rtort_chkp, NULL, rtrcp)) 1747 (void)cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, rtrcp, NULL); // Back out. 1748 } 1749 1750 // If assigned some completed work, do it! 1751 rtrcp_assigner = READ_ONCE(rtrcp->rtc_assigner); 1752 if (!rtrcp_assigner || !smp_load_acquire(&rtrcp_assigner->rtc_ready)) 1753 return; // No work or work not yet ready. 1754 rdrchked = rtrcp_assigner->rtc_chkrdr; 1755 if (WARN_ON_ONCE(rdrchked < 0)) 1756 return; 1757 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked]; 1758 loops = READ_ONCE(rtrcp_chked->rtc_myloops); 1759 atomic_inc(&n_rcu_torture_mbchk_tries); 1760 if (ULONG_CMP_LT(loops, rtrcp_assigner->rtc_chkloops)) 1761 atomic_inc(&n_rcu_torture_mbchk_fail); 1762 rtrcp_assigner->rtc_chkloops = loops + ULONG_MAX / 2; 1763 rtrcp_assigner->rtc_ready = 0; 1764 smp_store_release(&rtrcp->rtc_assigner, NULL); // Someone else can assign us work. 1765 smp_store_release(&rtrcp_assigner->rtc_chkrdr, -1); // Assigner can again assign. 1766 } 1767 1768 /* 1769 * Do one extension of an RCU read-side critical section using the 1770 * current reader state in readstate (set to zero for initial entry 1771 * to extended critical section), set the new state as specified by 1772 * newstate (set to zero for final exit from extended critical section), 1773 * and random-number-generator state in trsp. If this is neither the 1774 * beginning or end of the critical section and if there was actually a 1775 * change, do a ->read_delay(). 1776 */ rcutorture_one_extend(int * readstate,int newstate,struct torture_random_state * trsp,struct rt_read_seg * rtrsp)1777 static void rcutorture_one_extend(int *readstate, int newstate, 1778 struct torture_random_state *trsp, 1779 struct rt_read_seg *rtrsp) 1780 { 1781 unsigned long flags; 1782 int idxnew1 = -1; 1783 int idxnew2 = -1; 1784 int idxold1 = *readstate; 1785 int idxold2 = idxold1; 1786 int statesnew = ~*readstate & newstate; 1787 int statesold = *readstate & ~newstate; 1788 1789 WARN_ON_ONCE(idxold2 < 0); 1790 WARN_ON_ONCE((idxold2 >> RCUTORTURE_RDR_SHIFT_2) > 1); 1791 rtrsp->rt_readstate = newstate; 1792 1793 /* First, put new protection in place to avoid critical-section gap. */ 1794 if (statesnew & RCUTORTURE_RDR_BH) 1795 local_bh_disable(); 1796 if (statesnew & RCUTORTURE_RDR_RBH) 1797 rcu_read_lock_bh(); 1798 if (statesnew & RCUTORTURE_RDR_IRQ) 1799 local_irq_disable(); 1800 if (statesnew & RCUTORTURE_RDR_PREEMPT) 1801 preempt_disable(); 1802 if (statesnew & RCUTORTURE_RDR_SCHED) 1803 rcu_read_lock_sched(); 1804 if (statesnew & RCUTORTURE_RDR_RCU_1) 1805 idxnew1 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_1; 1806 if (statesnew & RCUTORTURE_RDR_RCU_2) 1807 idxnew2 = (cur_ops->readlock() & 0x1) << RCUTORTURE_RDR_SHIFT_2; 1808 1809 /* 1810 * Next, remove old protection, in decreasing order of strength 1811 * to avoid unlock paths that aren't safe in the stronger 1812 * context. Namely: BH can not be enabled with disabled interrupts. 1813 * Additionally PREEMPT_RT requires that BH is enabled in preemptible 1814 * context. 1815 */ 1816 if (statesold & RCUTORTURE_RDR_IRQ) 1817 local_irq_enable(); 1818 if (statesold & RCUTORTURE_RDR_PREEMPT) 1819 preempt_enable(); 1820 if (statesold & RCUTORTURE_RDR_SCHED) 1821 rcu_read_unlock_sched(); 1822 if (statesold & RCUTORTURE_RDR_BH) 1823 local_bh_enable(); 1824 if (statesold & RCUTORTURE_RDR_RBH) 1825 rcu_read_unlock_bh(); 1826 if (statesold & RCUTORTURE_RDR_RCU_2) { 1827 cur_ops->readunlock((idxold2 >> RCUTORTURE_RDR_SHIFT_2) & 0x1); 1828 WARN_ON_ONCE(idxnew2 != -1); 1829 idxold2 = 0; 1830 } 1831 if (statesold & RCUTORTURE_RDR_RCU_1) { 1832 bool lockit; 1833 1834 lockit = !cur_ops->no_pi_lock && !statesnew && !(torture_random(trsp) & 0xffff); 1835 if (lockit) 1836 raw_spin_lock_irqsave(¤t->pi_lock, flags); 1837 cur_ops->readunlock((idxold1 >> RCUTORTURE_RDR_SHIFT_1) & 0x1); 1838 WARN_ON_ONCE(idxnew1 != -1); 1839 idxold1 = 0; 1840 if (lockit) 1841 raw_spin_unlock_irqrestore(¤t->pi_lock, flags); 1842 } 1843 1844 /* Delay if neither beginning nor end and there was a change. */ 1845 if ((statesnew || statesold) && *readstate && newstate) 1846 cur_ops->read_delay(trsp, rtrsp); 1847 1848 /* Update the reader state. */ 1849 if (idxnew1 == -1) 1850 idxnew1 = idxold1 & RCUTORTURE_RDR_MASK_1; 1851 WARN_ON_ONCE(idxnew1 < 0); 1852 if (WARN_ON_ONCE((idxnew1 >> RCUTORTURE_RDR_SHIFT_1) > 1)) 1853 pr_info("Unexpected idxnew1 value of %#x\n", idxnew1); 1854 if (idxnew2 == -1) 1855 idxnew2 = idxold2 & RCUTORTURE_RDR_MASK_2; 1856 WARN_ON_ONCE(idxnew2 < 0); 1857 WARN_ON_ONCE((idxnew2 >> RCUTORTURE_RDR_SHIFT_2) > 1); 1858 *readstate = idxnew1 | idxnew2 | newstate; 1859 WARN_ON_ONCE(*readstate < 0); 1860 if (WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT_2) > 1)) 1861 pr_info("Unexpected idxnew2 value of %#x\n", idxnew2); 1862 } 1863 1864 /* Return the biggest extendables mask given current RCU and boot parameters. */ rcutorture_extend_mask_max(void)1865 static int rcutorture_extend_mask_max(void) 1866 { 1867 int mask; 1868 1869 WARN_ON_ONCE(extendables & ~RCUTORTURE_MAX_EXTEND); 1870 mask = extendables & RCUTORTURE_MAX_EXTEND & cur_ops->extendables; 1871 mask = mask | RCUTORTURE_RDR_RCU_1 | RCUTORTURE_RDR_RCU_2; 1872 return mask; 1873 } 1874 1875 /* Return a random protection state mask, but with at least one bit set. */ 1876 static int rcutorture_extend_mask(int oldmask,struct torture_random_state * trsp)1877 rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp) 1878 { 1879 int mask = rcutorture_extend_mask_max(); 1880 unsigned long randmask1 = torture_random(trsp); 1881 unsigned long randmask2 = randmask1 >> 3; 1882 unsigned long preempts = RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED; 1883 unsigned long preempts_irq = preempts | RCUTORTURE_RDR_IRQ; 1884 unsigned long bhs = RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH; 1885 1886 WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT_1); 1887 /* Mostly only one bit (need preemption!), sometimes lots of bits. */ 1888 if (!(randmask1 & 0x7)) 1889 mask = mask & randmask2; 1890 else 1891 mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS)); 1892 1893 // Can't have nested RCU reader without outer RCU reader. 1894 if (!(mask & RCUTORTURE_RDR_RCU_1) && (mask & RCUTORTURE_RDR_RCU_2)) { 1895 if (oldmask & RCUTORTURE_RDR_RCU_1) 1896 mask &= ~RCUTORTURE_RDR_RCU_2; 1897 else 1898 mask |= RCUTORTURE_RDR_RCU_1; 1899 } 1900 1901 /* 1902 * Can't enable bh w/irq disabled. 1903 */ 1904 if (mask & RCUTORTURE_RDR_IRQ) 1905 mask |= oldmask & bhs; 1906 1907 /* 1908 * Ideally these sequences would be detected in debug builds 1909 * (regardless of RT), but until then don't stop testing 1910 * them on non-RT. 1911 */ 1912 if (IS_ENABLED(CONFIG_PREEMPT_RT)) { 1913 /* Can't modify BH in atomic context */ 1914 if (oldmask & preempts_irq) 1915 mask &= ~bhs; 1916 if ((oldmask | mask) & preempts_irq) 1917 mask |= oldmask & bhs; 1918 } 1919 1920 return mask ?: RCUTORTURE_RDR_RCU_1; 1921 } 1922 1923 /* 1924 * Do a randomly selected number of extensions of an existing RCU read-side 1925 * critical section. 1926 */ 1927 static struct rt_read_seg * rcutorture_loop_extend(int * readstate,struct torture_random_state * trsp,struct rt_read_seg * rtrsp)1928 rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp, 1929 struct rt_read_seg *rtrsp) 1930 { 1931 int i; 1932 int j; 1933 int mask = rcutorture_extend_mask_max(); 1934 1935 WARN_ON_ONCE(!*readstate); /* -Existing- RCU read-side critsect! */ 1936 if (!((mask - 1) & mask)) 1937 return rtrsp; /* Current RCU reader not extendable. */ 1938 /* Bias towards larger numbers of loops. */ 1939 i = torture_random(trsp); 1940 i = ((i | (i >> 3)) & RCUTORTURE_RDR_MAX_LOOPS) + 1; 1941 for (j = 0; j < i; j++) { 1942 mask = rcutorture_extend_mask(*readstate, trsp); 1943 rcutorture_one_extend(readstate, mask, trsp, &rtrsp[j]); 1944 } 1945 return &rtrsp[j]; 1946 } 1947 1948 /* 1949 * Do one read-side critical section, returning false if there was 1950 * no data to read. Can be invoked both from process context and 1951 * from a timer handler. 1952 */ rcu_torture_one_read(struct torture_random_state * trsp,long myid)1953 static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid) 1954 { 1955 bool checkpolling = !(torture_random(trsp) & 0xfff); 1956 unsigned long cookie; 1957 struct rcu_gp_oldstate cookie_full; 1958 int i; 1959 unsigned long started; 1960 unsigned long completed; 1961 int newstate; 1962 struct rcu_torture *p; 1963 int pipe_count; 1964 int readstate = 0; 1965 struct rt_read_seg rtseg[RCUTORTURE_RDR_MAX_SEGS] = { { 0 } }; 1966 struct rt_read_seg *rtrsp = &rtseg[0]; 1967 struct rt_read_seg *rtrsp1; 1968 unsigned long long ts; 1969 1970 WARN_ON_ONCE(!rcu_is_watching()); 1971 newstate = rcutorture_extend_mask(readstate, trsp); 1972 rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++); 1973 if (checkpolling) { 1974 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) 1975 cookie = cur_ops->get_gp_state(); 1976 if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full) 1977 cur_ops->get_gp_state_full(&cookie_full); 1978 } 1979 started = cur_ops->get_gp_seq(); 1980 ts = rcu_trace_clock_local(); 1981 p = rcu_dereference_check(rcu_torture_current, 1982 !cur_ops->readlock_held || cur_ops->readlock_held()); 1983 if (p == NULL) { 1984 /* Wait for rcu_torture_writer to get underway */ 1985 rcutorture_one_extend(&readstate, 0, trsp, rtrsp); 1986 return false; 1987 } 1988 if (p->rtort_mbtest == 0) 1989 atomic_inc(&n_rcu_torture_mberror); 1990 rcu_torture_reader_do_mbchk(myid, p, trsp); 1991 rtrsp = rcutorture_loop_extend(&readstate, trsp, rtrsp); 1992 preempt_disable(); 1993 pipe_count = READ_ONCE(p->rtort_pipe_count); 1994 if (pipe_count > RCU_TORTURE_PIPE_LEN) { 1995 // Should not happen in a correct RCU implementation, 1996 // happens quite often for torture_type=busted. 1997 pipe_count = RCU_TORTURE_PIPE_LEN; 1998 } 1999 completed = cur_ops->get_gp_seq(); 2000 if (pipe_count > 1) { 2001 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, 2002 ts, started, completed); 2003 rcu_ftrace_dump(DUMP_ALL); 2004 } 2005 __this_cpu_inc(rcu_torture_count[pipe_count]); 2006 completed = rcutorture_seq_diff(completed, started); 2007 if (completed > RCU_TORTURE_PIPE_LEN) { 2008 /* Should not happen, but... */ 2009 completed = RCU_TORTURE_PIPE_LEN; 2010 } 2011 __this_cpu_inc(rcu_torture_batch[completed]); 2012 preempt_enable(); 2013 if (checkpolling) { 2014 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) 2015 WARN_ONCE(cur_ops->poll_gp_state(cookie), 2016 "%s: Cookie check 2 failed %s(%d) %lu->%lu\n", 2017 __func__, 2018 rcu_torture_writer_state_getname(), 2019 rcu_torture_writer_state, 2020 cookie, cur_ops->get_gp_state()); 2021 if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full) 2022 WARN_ONCE(cur_ops->poll_gp_state_full(&cookie_full), 2023 "%s: Cookie check 6 failed %s(%d) online %*pbl\n", 2024 __func__, 2025 rcu_torture_writer_state_getname(), 2026 rcu_torture_writer_state, 2027 cpumask_pr_args(cpu_online_mask)); 2028 } 2029 rcutorture_one_extend(&readstate, 0, trsp, rtrsp); 2030 WARN_ON_ONCE(readstate); 2031 // This next splat is expected behavior if leakpointer, especially 2032 // for CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels. 2033 WARN_ON_ONCE(leakpointer && READ_ONCE(p->rtort_pipe_count) > 1); 2034 2035 /* If error or close call, record the sequence of reader protections. */ 2036 if ((pipe_count > 1 || completed > 1) && !xchg(&err_segs_recorded, 1)) { 2037 i = 0; 2038 for (rtrsp1 = &rtseg[0]; rtrsp1 < rtrsp; rtrsp1++) 2039 err_segs[i++] = *rtrsp1; 2040 rt_read_nsegs = i; 2041 } 2042 2043 return true; 2044 } 2045 2046 static DEFINE_TORTURE_RANDOM_PERCPU(rcu_torture_timer_rand); 2047 2048 /* 2049 * RCU torture reader from timer handler. Dereferences rcu_torture_current, 2050 * incrementing the corresponding element of the pipeline array. The 2051 * counter in the element should never be greater than 1, otherwise, the 2052 * RCU implementation is broken. 2053 */ rcu_torture_timer(struct timer_list * unused)2054 static void rcu_torture_timer(struct timer_list *unused) 2055 { 2056 atomic_long_inc(&n_rcu_torture_timers); 2057 (void)rcu_torture_one_read(this_cpu_ptr(&rcu_torture_timer_rand), -1); 2058 2059 /* Test call_rcu() invocation from interrupt handler. */ 2060 if (cur_ops->call) { 2061 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT); 2062 2063 if (rhp) 2064 cur_ops->call(rhp, rcu_torture_timer_cb); 2065 } 2066 } 2067 2068 /* 2069 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current, 2070 * incrementing the corresponding element of the pipeline array. The 2071 * counter in the element should never be greater than 1, otherwise, the 2072 * RCU implementation is broken. 2073 */ 2074 static int rcu_torture_reader(void * arg)2075 rcu_torture_reader(void *arg) 2076 { 2077 unsigned long lastsleep = jiffies; 2078 long myid = (long)arg; 2079 int mynumonline = myid; 2080 DEFINE_TORTURE_RANDOM(rand); 2081 struct timer_list t; 2082 2083 VERBOSE_TOROUT_STRING("rcu_torture_reader task started"); 2084 set_user_nice(current, MAX_NICE); 2085 if (irqreader && cur_ops->irq_capable) 2086 timer_setup_on_stack(&t, rcu_torture_timer, 0); 2087 tick_dep_set_task(current, TICK_DEP_BIT_RCU); 2088 do { 2089 if (irqreader && cur_ops->irq_capable) { 2090 if (!timer_pending(&t)) 2091 mod_timer(&t, jiffies + 1); 2092 } 2093 if (!rcu_torture_one_read(&rand, myid) && !torture_must_stop()) 2094 schedule_timeout_interruptible(HZ); 2095 if (time_after(jiffies, lastsleep) && !torture_must_stop()) { 2096 torture_hrtimeout_us(500, 1000, &rand); 2097 lastsleep = jiffies + 10; 2098 } 2099 while (torture_num_online_cpus() < mynumonline && !torture_must_stop()) 2100 schedule_timeout_interruptible(HZ / 5); 2101 stutter_wait("rcu_torture_reader"); 2102 } while (!torture_must_stop()); 2103 if (irqreader && cur_ops->irq_capable) { 2104 del_timer_sync(&t); 2105 destroy_timer_on_stack(&t); 2106 } 2107 tick_dep_clear_task(current, TICK_DEP_BIT_RCU); 2108 torture_kthread_stopping("rcu_torture_reader"); 2109 return 0; 2110 } 2111 2112 /* 2113 * Randomly Toggle CPUs' callback-offload state. This uses hrtimers to 2114 * increase race probabilities and fuzzes the interval between toggling. 2115 */ rcu_nocb_toggle(void * arg)2116 static int rcu_nocb_toggle(void *arg) 2117 { 2118 int cpu; 2119 int maxcpu = -1; 2120 int oldnice = task_nice(current); 2121 long r; 2122 DEFINE_TORTURE_RANDOM(rand); 2123 ktime_t toggle_delay; 2124 unsigned long toggle_fuzz; 2125 ktime_t toggle_interval = ms_to_ktime(nocbs_toggle); 2126 2127 VERBOSE_TOROUT_STRING("rcu_nocb_toggle task started"); 2128 while (!rcu_inkernel_boot_has_ended()) 2129 schedule_timeout_interruptible(HZ / 10); 2130 for_each_online_cpu(cpu) 2131 maxcpu = cpu; 2132 WARN_ON(maxcpu < 0); 2133 if (toggle_interval > ULONG_MAX) 2134 toggle_fuzz = ULONG_MAX >> 3; 2135 else 2136 toggle_fuzz = toggle_interval >> 3; 2137 if (toggle_fuzz <= 0) 2138 toggle_fuzz = NSEC_PER_USEC; 2139 do { 2140 r = torture_random(&rand); 2141 cpu = (r >> 1) % (maxcpu + 1); 2142 if (r & 0x1) { 2143 rcu_nocb_cpu_offload(cpu); 2144 atomic_long_inc(&n_nocb_offload); 2145 } else { 2146 rcu_nocb_cpu_deoffload(cpu); 2147 atomic_long_inc(&n_nocb_deoffload); 2148 } 2149 toggle_delay = torture_random(&rand) % toggle_fuzz + toggle_interval; 2150 set_current_state(TASK_INTERRUPTIBLE); 2151 schedule_hrtimeout(&toggle_delay, HRTIMER_MODE_REL); 2152 if (stutter_wait("rcu_nocb_toggle")) 2153 sched_set_normal(current, oldnice); 2154 } while (!torture_must_stop()); 2155 torture_kthread_stopping("rcu_nocb_toggle"); 2156 return 0; 2157 } 2158 2159 /* 2160 * Print torture statistics. Caller must ensure that there is only 2161 * one call to this function at a given time!!! This is normally 2162 * accomplished by relying on the module system to only have one copy 2163 * of the module loaded, and then by giving the rcu_torture_stats 2164 * kthread full control (or the init/cleanup functions when rcu_torture_stats 2165 * thread is not running). 2166 */ 2167 static void rcu_torture_stats_print(void)2168 rcu_torture_stats_print(void) 2169 { 2170 int cpu; 2171 int i; 2172 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; 2173 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; 2174 struct rcu_torture *rtcp; 2175 static unsigned long rtcv_snap = ULONG_MAX; 2176 static bool splatted; 2177 struct task_struct *wtp; 2178 2179 for_each_possible_cpu(cpu) { 2180 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 2181 pipesummary[i] += READ_ONCE(per_cpu(rcu_torture_count, cpu)[i]); 2182 batchsummary[i] += READ_ONCE(per_cpu(rcu_torture_batch, cpu)[i]); 2183 } 2184 } 2185 for (i = RCU_TORTURE_PIPE_LEN; i >= 0; i--) { 2186 if (pipesummary[i] != 0) 2187 break; 2188 } 2189 2190 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 2191 rtcp = rcu_access_pointer(rcu_torture_current); 2192 pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ", 2193 rtcp, 2194 rtcp && !rcu_stall_is_suppressed_at_boot() ? "ver" : "VER", 2195 rcu_torture_current_version, 2196 list_empty(&rcu_torture_freelist), 2197 atomic_read(&n_rcu_torture_alloc), 2198 atomic_read(&n_rcu_torture_alloc_fail), 2199 atomic_read(&n_rcu_torture_free)); 2200 pr_cont("rtmbe: %d rtmbkf: %d/%d rtbe: %ld rtbke: %ld ", 2201 atomic_read(&n_rcu_torture_mberror), 2202 atomic_read(&n_rcu_torture_mbchk_fail), atomic_read(&n_rcu_torture_mbchk_tries), 2203 n_rcu_torture_barrier_error, 2204 n_rcu_torture_boost_ktrerror); 2205 pr_cont("rtbf: %ld rtb: %ld nt: %ld ", 2206 n_rcu_torture_boost_failure, 2207 n_rcu_torture_boosts, 2208 atomic_long_read(&n_rcu_torture_timers)); 2209 torture_onoff_stats(); 2210 pr_cont("barrier: %ld/%ld:%ld ", 2211 data_race(n_barrier_successes), 2212 data_race(n_barrier_attempts), 2213 data_race(n_rcu_torture_barrier_error)); 2214 pr_cont("read-exits: %ld ", data_race(n_read_exits)); // Statistic. 2215 pr_cont("nocb-toggles: %ld:%ld\n", 2216 atomic_long_read(&n_nocb_offload), atomic_long_read(&n_nocb_deoffload)); 2217 2218 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 2219 if (atomic_read(&n_rcu_torture_mberror) || 2220 atomic_read(&n_rcu_torture_mbchk_fail) || 2221 n_rcu_torture_barrier_error || n_rcu_torture_boost_ktrerror || 2222 n_rcu_torture_boost_failure || i > 1) { 2223 pr_cont("%s", "!!! "); 2224 atomic_inc(&n_rcu_torture_error); 2225 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mberror)); 2226 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mbchk_fail)); 2227 WARN_ON_ONCE(n_rcu_torture_barrier_error); // rcu_barrier() 2228 WARN_ON_ONCE(n_rcu_torture_boost_ktrerror); // no boost kthread 2229 WARN_ON_ONCE(n_rcu_torture_boost_failure); // boost failed (TIMER_SOFTIRQ RT prio?) 2230 WARN_ON_ONCE(i > 1); // Too-short grace period 2231 } 2232 pr_cont("Reader Pipe: "); 2233 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 2234 pr_cont(" %ld", pipesummary[i]); 2235 pr_cont("\n"); 2236 2237 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 2238 pr_cont("Reader Batch: "); 2239 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 2240 pr_cont(" %ld", batchsummary[i]); 2241 pr_cont("\n"); 2242 2243 pr_alert("%s%s ", torture_type, TORTURE_FLAG); 2244 pr_cont("Free-Block Circulation: "); 2245 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 2246 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i])); 2247 } 2248 pr_cont("\n"); 2249 2250 if (cur_ops->stats) 2251 cur_ops->stats(); 2252 if (rtcv_snap == rcu_torture_current_version && 2253 rcu_access_pointer(rcu_torture_current) && 2254 !rcu_stall_is_suppressed()) { 2255 int __maybe_unused flags = 0; 2256 unsigned long __maybe_unused gp_seq = 0; 2257 2258 rcutorture_get_gp_data(cur_ops->ttype, 2259 &flags, &gp_seq); 2260 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, 2261 &flags, &gp_seq); 2262 wtp = READ_ONCE(writer_task); 2263 pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#x cpu %d\n", 2264 rcu_torture_writer_state_getname(), 2265 rcu_torture_writer_state, gp_seq, flags, 2266 wtp == NULL ? ~0U : wtp->__state, 2267 wtp == NULL ? -1 : (int)task_cpu(wtp)); 2268 if (!splatted && wtp) { 2269 sched_show_task(wtp); 2270 splatted = true; 2271 } 2272 if (cur_ops->gp_kthread_dbg) 2273 cur_ops->gp_kthread_dbg(); 2274 rcu_ftrace_dump(DUMP_ALL); 2275 } 2276 rtcv_snap = rcu_torture_current_version; 2277 } 2278 2279 /* 2280 * Periodically prints torture statistics, if periodic statistics printing 2281 * was specified via the stat_interval module parameter. 2282 */ 2283 static int rcu_torture_stats(void * arg)2284 rcu_torture_stats(void *arg) 2285 { 2286 VERBOSE_TOROUT_STRING("rcu_torture_stats task started"); 2287 do { 2288 schedule_timeout_interruptible(stat_interval * HZ); 2289 rcu_torture_stats_print(); 2290 torture_shutdown_absorb("rcu_torture_stats"); 2291 } while (!torture_must_stop()); 2292 torture_kthread_stopping("rcu_torture_stats"); 2293 return 0; 2294 } 2295 2296 /* Test mem_dump_obj() and friends. */ rcu_torture_mem_dump_obj(void)2297 static void rcu_torture_mem_dump_obj(void) 2298 { 2299 struct rcu_head *rhp; 2300 struct kmem_cache *kcp; 2301 static int z; 2302 2303 kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL); 2304 if (WARN_ON_ONCE(!kcp)) 2305 return; 2306 rhp = kmem_cache_alloc(kcp, GFP_KERNEL); 2307 if (WARN_ON_ONCE(!rhp)) { 2308 kmem_cache_destroy(kcp); 2309 return; 2310 } 2311 pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z); 2312 pr_alert("mem_dump_obj(ZERO_SIZE_PTR):"); 2313 mem_dump_obj(ZERO_SIZE_PTR); 2314 pr_alert("mem_dump_obj(NULL):"); 2315 mem_dump_obj(NULL); 2316 pr_alert("mem_dump_obj(%px):", &rhp); 2317 mem_dump_obj(&rhp); 2318 pr_alert("mem_dump_obj(%px):", rhp); 2319 mem_dump_obj(rhp); 2320 pr_alert("mem_dump_obj(%px):", &rhp->func); 2321 mem_dump_obj(&rhp->func); 2322 pr_alert("mem_dump_obj(%px):", &z); 2323 mem_dump_obj(&z); 2324 kmem_cache_free(kcp, rhp); 2325 kmem_cache_destroy(kcp); 2326 rhp = kmalloc(sizeof(*rhp), GFP_KERNEL); 2327 if (WARN_ON_ONCE(!rhp)) 2328 return; 2329 pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp); 2330 pr_alert("mem_dump_obj(kmalloc %px):", rhp); 2331 mem_dump_obj(rhp); 2332 pr_alert("mem_dump_obj(kmalloc %px):", &rhp->func); 2333 mem_dump_obj(&rhp->func); 2334 kfree(rhp); 2335 rhp = vmalloc(4096); 2336 if (WARN_ON_ONCE(!rhp)) 2337 return; 2338 pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp); 2339 pr_alert("mem_dump_obj(vmalloc %px):", rhp); 2340 mem_dump_obj(rhp); 2341 pr_alert("mem_dump_obj(vmalloc %px):", &rhp->func); 2342 mem_dump_obj(&rhp->func); 2343 vfree(rhp); 2344 } 2345 2346 static void rcu_torture_print_module_parms(struct rcu_torture_ops * cur_ops,const char * tag)2347 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag) 2348 { 2349 pr_alert("%s" TORTURE_FLAG 2350 "--- %s: nreaders=%d nfakewriters=%d " 2351 "stat_interval=%d verbose=%d test_no_idle_hz=%d " 2352 "shuffle_interval=%d stutter=%d irqreader=%d " 2353 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d " 2354 "test_boost=%d/%d test_boost_interval=%d " 2355 "test_boost_duration=%d shutdown_secs=%d " 2356 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d " 2357 "stall_cpu_block=%d " 2358 "n_barrier_cbs=%d " 2359 "onoff_interval=%d onoff_holdoff=%d " 2360 "read_exit_delay=%d read_exit_burst=%d " 2361 "nocbs_nthreads=%d nocbs_toggle=%d " 2362 "test_nmis=%d\n", 2363 torture_type, tag, nrealreaders, nfakewriters, 2364 stat_interval, verbose, test_no_idle_hz, shuffle_interval, 2365 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter, 2366 test_boost, cur_ops->can_boost, 2367 test_boost_interval, test_boost_duration, shutdown_secs, 2368 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff, 2369 stall_cpu_block, 2370 n_barrier_cbs, 2371 onoff_interval, onoff_holdoff, 2372 read_exit_delay, read_exit_burst, 2373 nocbs_nthreads, nocbs_toggle, 2374 test_nmis); 2375 } 2376 rcutorture_booster_cleanup(unsigned int cpu)2377 static int rcutorture_booster_cleanup(unsigned int cpu) 2378 { 2379 struct task_struct *t; 2380 2381 if (boost_tasks[cpu] == NULL) 2382 return 0; 2383 mutex_lock(&boost_mutex); 2384 t = boost_tasks[cpu]; 2385 boost_tasks[cpu] = NULL; 2386 rcu_torture_enable_rt_throttle(); 2387 mutex_unlock(&boost_mutex); 2388 2389 /* This must be outside of the mutex, otherwise deadlock! */ 2390 torture_stop_kthread(rcu_torture_boost, t); 2391 return 0; 2392 } 2393 rcutorture_booster_init(unsigned int cpu)2394 static int rcutorture_booster_init(unsigned int cpu) 2395 { 2396 int retval; 2397 2398 if (boost_tasks[cpu] != NULL) 2399 return 0; /* Already created, nothing more to do. */ 2400 2401 // Testing RCU priority boosting requires rcutorture do 2402 // some serious abuse. Counter this by running ksoftirqd 2403 // at higher priority. 2404 if (IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)) { 2405 struct sched_param sp; 2406 struct task_struct *t; 2407 2408 t = per_cpu(ksoftirqd, cpu); 2409 WARN_ON_ONCE(!t); 2410 sp.sched_priority = 2; 2411 sched_setscheduler_nocheck(t, SCHED_FIFO, &sp); 2412 } 2413 2414 /* Don't allow time recalculation while creating a new task. */ 2415 mutex_lock(&boost_mutex); 2416 rcu_torture_disable_rt_throttle(); 2417 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task"); 2418 boost_tasks[cpu] = kthread_run_on_cpu(rcu_torture_boost, NULL, 2419 cpu, "rcu_torture_boost_%u"); 2420 if (IS_ERR(boost_tasks[cpu])) { 2421 retval = PTR_ERR(boost_tasks[cpu]); 2422 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed"); 2423 n_rcu_torture_boost_ktrerror++; 2424 boost_tasks[cpu] = NULL; 2425 mutex_unlock(&boost_mutex); 2426 return retval; 2427 } 2428 mutex_unlock(&boost_mutex); 2429 return 0; 2430 } 2431 2432 /* 2433 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then 2434 * induces a CPU stall for the time specified by stall_cpu. 2435 */ rcu_torture_stall(void * args)2436 static int rcu_torture_stall(void *args) 2437 { 2438 int idx; 2439 unsigned long stop_at; 2440 2441 VERBOSE_TOROUT_STRING("rcu_torture_stall task started"); 2442 if (stall_cpu_holdoff > 0) { 2443 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff"); 2444 schedule_timeout_interruptible(stall_cpu_holdoff * HZ); 2445 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff"); 2446 } 2447 if (!kthread_should_stop() && stall_gp_kthread > 0) { 2448 VERBOSE_TOROUT_STRING("rcu_torture_stall begin GP stall"); 2449 rcu_gp_set_torture_wait(stall_gp_kthread * HZ); 2450 for (idx = 0; idx < stall_gp_kthread + 2; idx++) { 2451 if (kthread_should_stop()) 2452 break; 2453 schedule_timeout_uninterruptible(HZ); 2454 } 2455 } 2456 if (!kthread_should_stop() && stall_cpu > 0) { 2457 VERBOSE_TOROUT_STRING("rcu_torture_stall begin CPU stall"); 2458 stop_at = ktime_get_seconds() + stall_cpu; 2459 /* RCU CPU stall is expected behavior in following code. */ 2460 idx = cur_ops->readlock(); 2461 if (stall_cpu_irqsoff) 2462 local_irq_disable(); 2463 else if (!stall_cpu_block) 2464 preempt_disable(); 2465 pr_alert("%s start on CPU %d.\n", 2466 __func__, raw_smp_processor_id()); 2467 while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(), stop_at) && 2468 !kthread_should_stop()) 2469 if (stall_cpu_block) { 2470 #ifdef CONFIG_PREEMPTION 2471 preempt_schedule(); 2472 #else 2473 schedule_timeout_uninterruptible(HZ); 2474 #endif 2475 } else if (stall_no_softlockup) { 2476 touch_softlockup_watchdog(); 2477 } 2478 if (stall_cpu_irqsoff) 2479 local_irq_enable(); 2480 else if (!stall_cpu_block) 2481 preempt_enable(); 2482 cur_ops->readunlock(idx); 2483 } 2484 pr_alert("%s end.\n", __func__); 2485 torture_shutdown_absorb("rcu_torture_stall"); 2486 while (!kthread_should_stop()) 2487 schedule_timeout_interruptible(10 * HZ); 2488 return 0; 2489 } 2490 2491 /* Spawn CPU-stall kthread, if stall_cpu specified. */ rcu_torture_stall_init(void)2492 static int __init rcu_torture_stall_init(void) 2493 { 2494 if (stall_cpu <= 0 && stall_gp_kthread <= 0) 2495 return 0; 2496 return torture_create_kthread(rcu_torture_stall, NULL, stall_task); 2497 } 2498 2499 /* State structure for forward-progress self-propagating RCU callback. */ 2500 struct fwd_cb_state { 2501 struct rcu_head rh; 2502 int stop; 2503 }; 2504 2505 /* 2506 * Forward-progress self-propagating RCU callback function. Because 2507 * callbacks run from softirq, this function is an implicit RCU read-side 2508 * critical section. 2509 */ rcu_torture_fwd_prog_cb(struct rcu_head * rhp)2510 static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp) 2511 { 2512 struct fwd_cb_state *fcsp = container_of(rhp, struct fwd_cb_state, rh); 2513 2514 if (READ_ONCE(fcsp->stop)) { 2515 WRITE_ONCE(fcsp->stop, 2); 2516 return; 2517 } 2518 cur_ops->call(&fcsp->rh, rcu_torture_fwd_prog_cb); 2519 } 2520 2521 /* State for continuous-flood RCU callbacks. */ 2522 struct rcu_fwd_cb { 2523 struct rcu_head rh; 2524 struct rcu_fwd_cb *rfc_next; 2525 struct rcu_fwd *rfc_rfp; 2526 int rfc_gps; 2527 }; 2528 2529 #define MAX_FWD_CB_JIFFIES (8 * HZ) /* Maximum CB test duration. */ 2530 #define MIN_FWD_CB_LAUNDERS 3 /* This many CB invocations to count. */ 2531 #define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */ 2532 #define FWD_CBS_HIST_DIV 10 /* Histogram buckets/second. */ 2533 #define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV)) 2534 2535 struct rcu_launder_hist { 2536 long n_launders; 2537 unsigned long launder_gp_seq; 2538 }; 2539 2540 struct rcu_fwd { 2541 spinlock_t rcu_fwd_lock; 2542 struct rcu_fwd_cb *rcu_fwd_cb_head; 2543 struct rcu_fwd_cb **rcu_fwd_cb_tail; 2544 long n_launders_cb; 2545 unsigned long rcu_fwd_startat; 2546 struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST]; 2547 unsigned long rcu_launder_gp_seq_start; 2548 int rcu_fwd_id; 2549 }; 2550 2551 static DEFINE_MUTEX(rcu_fwd_mutex); 2552 static struct rcu_fwd *rcu_fwds; 2553 static unsigned long rcu_fwd_seq; 2554 static atomic_long_t rcu_fwd_max_cbs; 2555 static bool rcu_fwd_emergency_stop; 2556 rcu_torture_fwd_cb_hist(struct rcu_fwd * rfp)2557 static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp) 2558 { 2559 unsigned long gps; 2560 unsigned long gps_old; 2561 int i; 2562 int j; 2563 2564 for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--) 2565 if (rfp->n_launders_hist[i].n_launders > 0) 2566 break; 2567 pr_alert("%s: Callback-invocation histogram %d (duration %lu jiffies):", 2568 __func__, rfp->rcu_fwd_id, jiffies - rfp->rcu_fwd_startat); 2569 gps_old = rfp->rcu_launder_gp_seq_start; 2570 for (j = 0; j <= i; j++) { 2571 gps = rfp->n_launders_hist[j].launder_gp_seq; 2572 pr_cont(" %ds/%d: %ld:%ld", 2573 j + 1, FWD_CBS_HIST_DIV, 2574 rfp->n_launders_hist[j].n_launders, 2575 rcutorture_seq_diff(gps, gps_old)); 2576 gps_old = gps; 2577 } 2578 pr_cont("\n"); 2579 } 2580 2581 /* Callback function for continuous-flood RCU callbacks. */ rcu_torture_fwd_cb_cr(struct rcu_head * rhp)2582 static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp) 2583 { 2584 unsigned long flags; 2585 int i; 2586 struct rcu_fwd_cb *rfcp = container_of(rhp, struct rcu_fwd_cb, rh); 2587 struct rcu_fwd_cb **rfcpp; 2588 struct rcu_fwd *rfp = rfcp->rfc_rfp; 2589 2590 rfcp->rfc_next = NULL; 2591 rfcp->rfc_gps++; 2592 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags); 2593 rfcpp = rfp->rcu_fwd_cb_tail; 2594 rfp->rcu_fwd_cb_tail = &rfcp->rfc_next; 2595 smp_store_release(rfcpp, rfcp); 2596 WRITE_ONCE(rfp->n_launders_cb, rfp->n_launders_cb + 1); 2597 i = ((jiffies - rfp->rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV)); 2598 if (i >= ARRAY_SIZE(rfp->n_launders_hist)) 2599 i = ARRAY_SIZE(rfp->n_launders_hist) - 1; 2600 rfp->n_launders_hist[i].n_launders++; 2601 rfp->n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq(); 2602 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 2603 } 2604 2605 // Give the scheduler a chance, even on nohz_full CPUs. rcu_torture_fwd_prog_cond_resched(unsigned long iter)2606 static void rcu_torture_fwd_prog_cond_resched(unsigned long iter) 2607 { 2608 if (IS_ENABLED(CONFIG_PREEMPTION) && IS_ENABLED(CONFIG_NO_HZ_FULL)) { 2609 // Real call_rcu() floods hit userspace, so emulate that. 2610 if (need_resched() || (iter & 0xfff)) 2611 schedule(); 2612 return; 2613 } 2614 // No userspace emulation: CB invocation throttles call_rcu() 2615 cond_resched(); 2616 } 2617 2618 /* 2619 * Free all callbacks on the rcu_fwd_cb_head list, either because the 2620 * test is over or because we hit an OOM event. 2621 */ rcu_torture_fwd_prog_cbfree(struct rcu_fwd * rfp)2622 static unsigned long rcu_torture_fwd_prog_cbfree(struct rcu_fwd *rfp) 2623 { 2624 unsigned long flags; 2625 unsigned long freed = 0; 2626 struct rcu_fwd_cb *rfcp; 2627 2628 for (;;) { 2629 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags); 2630 rfcp = rfp->rcu_fwd_cb_head; 2631 if (!rfcp) { 2632 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 2633 break; 2634 } 2635 rfp->rcu_fwd_cb_head = rfcp->rfc_next; 2636 if (!rfp->rcu_fwd_cb_head) 2637 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head; 2638 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags); 2639 kfree(rfcp); 2640 freed++; 2641 rcu_torture_fwd_prog_cond_resched(freed); 2642 if (tick_nohz_full_enabled()) { 2643 local_irq_save(flags); 2644 rcu_momentary_dyntick_idle(); 2645 local_irq_restore(flags); 2646 } 2647 } 2648 return freed; 2649 } 2650 2651 /* Carry out need_resched()/cond_resched() forward-progress testing. */ rcu_torture_fwd_prog_nr(struct rcu_fwd * rfp,int * tested,int * tested_tries)2652 static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp, 2653 int *tested, int *tested_tries) 2654 { 2655 unsigned long cver; 2656 unsigned long dur; 2657 struct fwd_cb_state fcs; 2658 unsigned long gps; 2659 int idx; 2660 int sd; 2661 int sd4; 2662 bool selfpropcb = false; 2663 unsigned long stopat; 2664 static DEFINE_TORTURE_RANDOM(trs); 2665 2666 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id); 2667 if (!cur_ops->sync) 2668 return; // Cannot do need_resched() forward progress testing without ->sync. 2669 if (cur_ops->call && cur_ops->cb_barrier) { 2670 init_rcu_head_on_stack(&fcs.rh); 2671 selfpropcb = true; 2672 } 2673 2674 /* Tight loop containing cond_resched(). */ 2675 atomic_inc(&rcu_fwd_cb_nodelay); 2676 cur_ops->sync(); /* Later readers see above write. */ 2677 if (selfpropcb) { 2678 WRITE_ONCE(fcs.stop, 0); 2679 cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb); 2680 } 2681 cver = READ_ONCE(rcu_torture_current_version); 2682 gps = cur_ops->get_gp_seq(); 2683 sd = cur_ops->stall_dur() + 1; 2684 sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div; 2685 dur = sd4 + torture_random(&trs) % (sd - sd4); 2686 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies); 2687 stopat = rfp->rcu_fwd_startat + dur; 2688 while (time_before(jiffies, stopat) && 2689 !shutdown_time_arrived() && 2690 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 2691 idx = cur_ops->readlock(); 2692 udelay(10); 2693 cur_ops->readunlock(idx); 2694 if (!fwd_progress_need_resched || need_resched()) 2695 cond_resched(); 2696 } 2697 (*tested_tries)++; 2698 if (!time_before(jiffies, stopat) && 2699 !shutdown_time_arrived() && 2700 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 2701 (*tested)++; 2702 cver = READ_ONCE(rcu_torture_current_version) - cver; 2703 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps); 2704 WARN_ON(!cver && gps < 2); 2705 pr_alert("%s: %d Duration %ld cver %ld gps %ld\n", __func__, 2706 rfp->rcu_fwd_id, dur, cver, gps); 2707 } 2708 if (selfpropcb) { 2709 WRITE_ONCE(fcs.stop, 1); 2710 cur_ops->sync(); /* Wait for running CB to complete. */ 2711 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id); 2712 cur_ops->cb_barrier(); /* Wait for queued callbacks. */ 2713 } 2714 2715 if (selfpropcb) { 2716 WARN_ON(READ_ONCE(fcs.stop) != 2); 2717 destroy_rcu_head_on_stack(&fcs.rh); 2718 } 2719 schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */ 2720 atomic_dec(&rcu_fwd_cb_nodelay); 2721 } 2722 2723 /* Carry out call_rcu() forward-progress testing. */ rcu_torture_fwd_prog_cr(struct rcu_fwd * rfp)2724 static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp) 2725 { 2726 unsigned long cver; 2727 unsigned long flags; 2728 unsigned long gps; 2729 int i; 2730 long n_launders; 2731 long n_launders_cb_snap; 2732 long n_launders_sa; 2733 long n_max_cbs; 2734 long n_max_gps; 2735 struct rcu_fwd_cb *rfcp; 2736 struct rcu_fwd_cb *rfcpn; 2737 unsigned long stopat; 2738 unsigned long stoppedat; 2739 2740 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id); 2741 if (READ_ONCE(rcu_fwd_emergency_stop)) 2742 return; /* Get out of the way quickly, no GP wait! */ 2743 if (!cur_ops->call) 2744 return; /* Can't do call_rcu() fwd prog without ->call. */ 2745 2746 /* Loop continuously posting RCU callbacks. */ 2747 atomic_inc(&rcu_fwd_cb_nodelay); 2748 cur_ops->sync(); /* Later readers see above write. */ 2749 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies); 2750 stopat = rfp->rcu_fwd_startat + MAX_FWD_CB_JIFFIES; 2751 n_launders = 0; 2752 rfp->n_launders_cb = 0; // Hoist initialization for multi-kthread 2753 n_launders_sa = 0; 2754 n_max_cbs = 0; 2755 n_max_gps = 0; 2756 for (i = 0; i < ARRAY_SIZE(rfp->n_launders_hist); i++) 2757 rfp->n_launders_hist[i].n_launders = 0; 2758 cver = READ_ONCE(rcu_torture_current_version); 2759 gps = cur_ops->get_gp_seq(); 2760 rfp->rcu_launder_gp_seq_start = gps; 2761 tick_dep_set_task(current, TICK_DEP_BIT_RCU); 2762 while (time_before(jiffies, stopat) && 2763 !shutdown_time_arrived() && 2764 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) { 2765 rfcp = READ_ONCE(rfp->rcu_fwd_cb_head); 2766 rfcpn = NULL; 2767 if (rfcp) 2768 rfcpn = READ_ONCE(rfcp->rfc_next); 2769 if (rfcpn) { 2770 if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS && 2771 ++n_max_gps >= MIN_FWD_CBS_LAUNDERED) 2772 break; 2773 rfp->rcu_fwd_cb_head = rfcpn; 2774 n_launders++; 2775 n_launders_sa++; 2776 } else if (!cur_ops->cbflood_max || cur_ops->cbflood_max > n_max_cbs) { 2777 rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL); 2778 if (WARN_ON_ONCE(!rfcp)) { 2779 schedule_timeout_interruptible(1); 2780 continue; 2781 } 2782 n_max_cbs++; 2783 n_launders_sa = 0; 2784 rfcp->rfc_gps = 0; 2785 rfcp->rfc_rfp = rfp; 2786 } else { 2787 rfcp = NULL; 2788 } 2789 if (rfcp) 2790 cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr); 2791 rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs); 2792 if (tick_nohz_full_enabled()) { 2793 local_irq_save(flags); 2794 rcu_momentary_dyntick_idle(); 2795 local_irq_restore(flags); 2796 } 2797 } 2798 stoppedat = jiffies; 2799 n_launders_cb_snap = READ_ONCE(rfp->n_launders_cb); 2800 cver = READ_ONCE(rcu_torture_current_version) - cver; 2801 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps); 2802 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id); 2803 cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */ 2804 (void)rcu_torture_fwd_prog_cbfree(rfp); 2805 2806 if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) && 2807 !shutdown_time_arrived()) { 2808 WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED); 2809 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", 2810 __func__, 2811 stoppedat - rfp->rcu_fwd_startat, jiffies - stoppedat, 2812 n_launders + n_max_cbs - n_launders_cb_snap, 2813 n_launders, n_launders_sa, 2814 n_max_gps, n_max_cbs, cver, gps); 2815 atomic_long_add(n_max_cbs, &rcu_fwd_max_cbs); 2816 mutex_lock(&rcu_fwd_mutex); // Serialize histograms. 2817 rcu_torture_fwd_cb_hist(rfp); 2818 mutex_unlock(&rcu_fwd_mutex); 2819 } 2820 schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */ 2821 tick_dep_clear_task(current, TICK_DEP_BIT_RCU); 2822 atomic_dec(&rcu_fwd_cb_nodelay); 2823 } 2824 2825 2826 /* 2827 * OOM notifier, but this only prints diagnostic information for the 2828 * current forward-progress test. 2829 */ rcutorture_oom_notify(struct notifier_block * self,unsigned long notused,void * nfreed)2830 static int rcutorture_oom_notify(struct notifier_block *self, 2831 unsigned long notused, void *nfreed) 2832 { 2833 int i; 2834 long ncbs; 2835 struct rcu_fwd *rfp; 2836 2837 mutex_lock(&rcu_fwd_mutex); 2838 rfp = rcu_fwds; 2839 if (!rfp) { 2840 mutex_unlock(&rcu_fwd_mutex); 2841 return NOTIFY_OK; 2842 } 2843 WARN(1, "%s invoked upon OOM during forward-progress testing.\n", 2844 __func__); 2845 for (i = 0; i < fwd_progress; i++) { 2846 rcu_torture_fwd_cb_hist(&rfp[i]); 2847 rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp[i].rcu_fwd_startat)) / 2); 2848 } 2849 WRITE_ONCE(rcu_fwd_emergency_stop, true); 2850 smp_mb(); /* Emergency stop before free and wait to avoid hangs. */ 2851 ncbs = 0; 2852 for (i = 0; i < fwd_progress; i++) 2853 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]); 2854 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs); 2855 cur_ops->cb_barrier(); 2856 ncbs = 0; 2857 for (i = 0; i < fwd_progress; i++) 2858 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]); 2859 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs); 2860 cur_ops->cb_barrier(); 2861 ncbs = 0; 2862 for (i = 0; i < fwd_progress; i++) 2863 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]); 2864 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs); 2865 smp_mb(); /* Frees before return to avoid redoing OOM. */ 2866 (*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */ 2867 pr_info("%s returning after OOM processing.\n", __func__); 2868 mutex_unlock(&rcu_fwd_mutex); 2869 return NOTIFY_OK; 2870 } 2871 2872 static struct notifier_block rcutorture_oom_nb = { 2873 .notifier_call = rcutorture_oom_notify 2874 }; 2875 2876 /* Carry out grace-period forward-progress testing. */ rcu_torture_fwd_prog(void * args)2877 static int rcu_torture_fwd_prog(void *args) 2878 { 2879 bool firsttime = true; 2880 long max_cbs; 2881 int oldnice = task_nice(current); 2882 unsigned long oldseq = READ_ONCE(rcu_fwd_seq); 2883 struct rcu_fwd *rfp = args; 2884 int tested = 0; 2885 int tested_tries = 0; 2886 2887 VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started"); 2888 rcu_bind_current_to_nocb(); 2889 if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST)) 2890 set_user_nice(current, MAX_NICE); 2891 do { 2892 if (!rfp->rcu_fwd_id) { 2893 schedule_timeout_interruptible(fwd_progress_holdoff * HZ); 2894 WRITE_ONCE(rcu_fwd_emergency_stop, false); 2895 if (!firsttime) { 2896 max_cbs = atomic_long_xchg(&rcu_fwd_max_cbs, 0); 2897 pr_alert("%s n_max_cbs: %ld\n", __func__, max_cbs); 2898 } 2899 firsttime = false; 2900 WRITE_ONCE(rcu_fwd_seq, rcu_fwd_seq + 1); 2901 } else { 2902 while (READ_ONCE(rcu_fwd_seq) == oldseq && !torture_must_stop()) 2903 schedule_timeout_interruptible(1); 2904 oldseq = READ_ONCE(rcu_fwd_seq); 2905 } 2906 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id); 2907 if (rcu_inkernel_boot_has_ended() && torture_num_online_cpus() > rfp->rcu_fwd_id) 2908 rcu_torture_fwd_prog_cr(rfp); 2909 if ((cur_ops->stall_dur && cur_ops->stall_dur() > 0) && 2910 (!IS_ENABLED(CONFIG_TINY_RCU) || 2911 (rcu_inkernel_boot_has_ended() && 2912 torture_num_online_cpus() > rfp->rcu_fwd_id))) 2913 rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries); 2914 2915 /* Avoid slow periods, better to test when busy. */ 2916 if (stutter_wait("rcu_torture_fwd_prog")) 2917 sched_set_normal(current, oldnice); 2918 } while (!torture_must_stop()); 2919 /* Short runs might not contain a valid forward-progress attempt. */ 2920 if (!rfp->rcu_fwd_id) { 2921 WARN_ON(!tested && tested_tries >= 5); 2922 pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries); 2923 } 2924 torture_kthread_stopping("rcu_torture_fwd_prog"); 2925 return 0; 2926 } 2927 2928 /* If forward-progress checking is requested and feasible, spawn the thread. */ rcu_torture_fwd_prog_init(void)2929 static int __init rcu_torture_fwd_prog_init(void) 2930 { 2931 int i; 2932 int ret = 0; 2933 struct rcu_fwd *rfp; 2934 2935 if (!fwd_progress) 2936 return 0; /* Not requested, so don't do it. */ 2937 if (fwd_progress >= nr_cpu_ids) { 2938 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Limiting fwd_progress to # CPUs.\n"); 2939 fwd_progress = nr_cpu_ids; 2940 } else if (fwd_progress < 0) { 2941 fwd_progress = nr_cpu_ids; 2942 } 2943 if ((!cur_ops->sync && !cur_ops->call) || 2944 (!cur_ops->cbflood_max && (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0)) || 2945 cur_ops == &rcu_busted_ops) { 2946 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test"); 2947 fwd_progress = 0; 2948 return 0; 2949 } 2950 if (stall_cpu > 0) { 2951 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing"); 2952 fwd_progress = 0; 2953 if (IS_MODULE(CONFIG_RCU_TORTURE_TEST)) 2954 return -EINVAL; /* In module, can fail back to user. */ 2955 WARN_ON(1); /* Make sure rcutorture notices conflict. */ 2956 return 0; 2957 } 2958 if (fwd_progress_holdoff <= 0) 2959 fwd_progress_holdoff = 1; 2960 if (fwd_progress_div <= 0) 2961 fwd_progress_div = 4; 2962 rfp = kcalloc(fwd_progress, sizeof(*rfp), GFP_KERNEL); 2963 fwd_prog_tasks = kcalloc(fwd_progress, sizeof(*fwd_prog_tasks), GFP_KERNEL); 2964 if (!rfp || !fwd_prog_tasks) { 2965 kfree(rfp); 2966 kfree(fwd_prog_tasks); 2967 fwd_prog_tasks = NULL; 2968 fwd_progress = 0; 2969 return -ENOMEM; 2970 } 2971 for (i = 0; i < fwd_progress; i++) { 2972 spin_lock_init(&rfp[i].rcu_fwd_lock); 2973 rfp[i].rcu_fwd_cb_tail = &rfp[i].rcu_fwd_cb_head; 2974 rfp[i].rcu_fwd_id = i; 2975 } 2976 mutex_lock(&rcu_fwd_mutex); 2977 rcu_fwds = rfp; 2978 mutex_unlock(&rcu_fwd_mutex); 2979 register_oom_notifier(&rcutorture_oom_nb); 2980 for (i = 0; i < fwd_progress; i++) { 2981 ret = torture_create_kthread(rcu_torture_fwd_prog, &rcu_fwds[i], fwd_prog_tasks[i]); 2982 if (ret) { 2983 fwd_progress = i; 2984 return ret; 2985 } 2986 } 2987 return 0; 2988 } 2989 rcu_torture_fwd_prog_cleanup(void)2990 static void rcu_torture_fwd_prog_cleanup(void) 2991 { 2992 int i; 2993 struct rcu_fwd *rfp; 2994 2995 if (!rcu_fwds || !fwd_prog_tasks) 2996 return; 2997 for (i = 0; i < fwd_progress; i++) 2998 torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_tasks[i]); 2999 unregister_oom_notifier(&rcutorture_oom_nb); 3000 mutex_lock(&rcu_fwd_mutex); 3001 rfp = rcu_fwds; 3002 rcu_fwds = NULL; 3003 mutex_unlock(&rcu_fwd_mutex); 3004 kfree(rfp); 3005 kfree(fwd_prog_tasks); 3006 fwd_prog_tasks = NULL; 3007 } 3008 3009 /* Callback function for RCU barrier testing. */ rcu_torture_barrier_cbf(struct rcu_head * rcu)3010 static void rcu_torture_barrier_cbf(struct rcu_head *rcu) 3011 { 3012 atomic_inc(&barrier_cbs_invoked); 3013 } 3014 3015 /* IPI handler to get callback posted on desired CPU, if online. */ rcu_torture_barrier1cb(void * rcu_void)3016 static int rcu_torture_barrier1cb(void *rcu_void) 3017 { 3018 struct rcu_head *rhp = rcu_void; 3019 3020 cur_ops->call(rhp, rcu_torture_barrier_cbf); 3021 return 0; 3022 } 3023 3024 /* kthread function to register callbacks used to test RCU barriers. */ rcu_torture_barrier_cbs(void * arg)3025 static int rcu_torture_barrier_cbs(void *arg) 3026 { 3027 long myid = (long)arg; 3028 bool lastphase = false; 3029 bool newphase; 3030 struct rcu_head rcu; 3031 3032 init_rcu_head_on_stack(&rcu); 3033 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started"); 3034 set_user_nice(current, MAX_NICE); 3035 do { 3036 wait_event(barrier_cbs_wq[myid], 3037 (newphase = 3038 smp_load_acquire(&barrier_phase)) != lastphase || 3039 torture_must_stop()); 3040 lastphase = newphase; 3041 if (torture_must_stop()) 3042 break; 3043 /* 3044 * The above smp_load_acquire() ensures barrier_phase load 3045 * is ordered before the following ->call(). 3046 */ 3047 if (smp_call_on_cpu(myid, rcu_torture_barrier1cb, &rcu, 1)) 3048 cur_ops->call(&rcu, rcu_torture_barrier_cbf); 3049 3050 if (atomic_dec_and_test(&barrier_cbs_count)) 3051 wake_up(&barrier_wq); 3052 } while (!torture_must_stop()); 3053 if (cur_ops->cb_barrier != NULL) 3054 cur_ops->cb_barrier(); 3055 destroy_rcu_head_on_stack(&rcu); 3056 torture_kthread_stopping("rcu_torture_barrier_cbs"); 3057 return 0; 3058 } 3059 3060 /* kthread function to drive and coordinate RCU barrier testing. */ rcu_torture_barrier(void * arg)3061 static int rcu_torture_barrier(void *arg) 3062 { 3063 int i; 3064 3065 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting"); 3066 do { 3067 atomic_set(&barrier_cbs_invoked, 0); 3068 atomic_set(&barrier_cbs_count, n_barrier_cbs); 3069 /* Ensure barrier_phase ordered after prior assignments. */ 3070 smp_store_release(&barrier_phase, !barrier_phase); 3071 for (i = 0; i < n_barrier_cbs; i++) 3072 wake_up(&barrier_cbs_wq[i]); 3073 wait_event(barrier_wq, 3074 atomic_read(&barrier_cbs_count) == 0 || 3075 torture_must_stop()); 3076 if (torture_must_stop()) 3077 break; 3078 n_barrier_attempts++; 3079 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */ 3080 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) { 3081 n_rcu_torture_barrier_error++; 3082 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n", 3083 atomic_read(&barrier_cbs_invoked), 3084 n_barrier_cbs); 3085 WARN_ON(1); 3086 // Wait manually for the remaining callbacks 3087 i = 0; 3088 do { 3089 if (WARN_ON(i++ > HZ)) 3090 i = INT_MIN; 3091 schedule_timeout_interruptible(1); 3092 cur_ops->cb_barrier(); 3093 } while (atomic_read(&barrier_cbs_invoked) != 3094 n_barrier_cbs && 3095 !torture_must_stop()); 3096 smp_mb(); // Can't trust ordering if broken. 3097 if (!torture_must_stop()) 3098 pr_err("Recovered: barrier_cbs_invoked = %d\n", 3099 atomic_read(&barrier_cbs_invoked)); 3100 } else { 3101 n_barrier_successes++; 3102 } 3103 schedule_timeout_interruptible(HZ / 10); 3104 } while (!torture_must_stop()); 3105 torture_kthread_stopping("rcu_torture_barrier"); 3106 return 0; 3107 } 3108 3109 /* Initialize RCU barrier testing. */ rcu_torture_barrier_init(void)3110 static int rcu_torture_barrier_init(void) 3111 { 3112 int i; 3113 int ret; 3114 3115 if (n_barrier_cbs <= 0) 3116 return 0; 3117 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) { 3118 pr_alert("%s" TORTURE_FLAG 3119 " Call or barrier ops missing for %s,\n", 3120 torture_type, cur_ops->name); 3121 pr_alert("%s" TORTURE_FLAG 3122 " RCU barrier testing omitted from run.\n", 3123 torture_type); 3124 return 0; 3125 } 3126 atomic_set(&barrier_cbs_count, 0); 3127 atomic_set(&barrier_cbs_invoked, 0); 3128 barrier_cbs_tasks = 3129 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]), 3130 GFP_KERNEL); 3131 barrier_cbs_wq = 3132 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL); 3133 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq) 3134 return -ENOMEM; 3135 for (i = 0; i < n_barrier_cbs; i++) { 3136 init_waitqueue_head(&barrier_cbs_wq[i]); 3137 ret = torture_create_kthread(rcu_torture_barrier_cbs, 3138 (void *)(long)i, 3139 barrier_cbs_tasks[i]); 3140 if (ret) 3141 return ret; 3142 } 3143 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task); 3144 } 3145 3146 /* Clean up after RCU barrier testing. */ rcu_torture_barrier_cleanup(void)3147 static void rcu_torture_barrier_cleanup(void) 3148 { 3149 int i; 3150 3151 torture_stop_kthread(rcu_torture_barrier, barrier_task); 3152 if (barrier_cbs_tasks != NULL) { 3153 for (i = 0; i < n_barrier_cbs; i++) 3154 torture_stop_kthread(rcu_torture_barrier_cbs, 3155 barrier_cbs_tasks[i]); 3156 kfree(barrier_cbs_tasks); 3157 barrier_cbs_tasks = NULL; 3158 } 3159 if (barrier_cbs_wq != NULL) { 3160 kfree(barrier_cbs_wq); 3161 barrier_cbs_wq = NULL; 3162 } 3163 } 3164 rcu_torture_can_boost(void)3165 static bool rcu_torture_can_boost(void) 3166 { 3167 static int boost_warn_once; 3168 int prio; 3169 3170 if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2) 3171 return false; 3172 if (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state) 3173 return false; 3174 3175 prio = rcu_get_gp_kthreads_prio(); 3176 if (!prio) 3177 return false; 3178 3179 if (prio < 2) { 3180 if (boost_warn_once == 1) 3181 return false; 3182 3183 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); 3184 boost_warn_once = 1; 3185 return false; 3186 } 3187 3188 return true; 3189 } 3190 3191 static bool read_exit_child_stop; 3192 static bool read_exit_child_stopped; 3193 static wait_queue_head_t read_exit_wq; 3194 3195 // Child kthread which just does an rcutorture reader and exits. rcu_torture_read_exit_child(void * trsp_in)3196 static int rcu_torture_read_exit_child(void *trsp_in) 3197 { 3198 struct torture_random_state *trsp = trsp_in; 3199 3200 set_user_nice(current, MAX_NICE); 3201 // Minimize time between reading and exiting. 3202 while (!kthread_should_stop()) 3203 schedule_timeout_uninterruptible(1); 3204 (void)rcu_torture_one_read(trsp, -1); 3205 return 0; 3206 } 3207 3208 // Parent kthread which creates and destroys read-exit child kthreads. rcu_torture_read_exit(void * unused)3209 static int rcu_torture_read_exit(void *unused) 3210 { 3211 bool errexit = false; 3212 int i; 3213 struct task_struct *tsp; 3214 DEFINE_TORTURE_RANDOM(trs); 3215 3216 // Allocate and initialize. 3217 set_user_nice(current, MAX_NICE); 3218 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of test"); 3219 3220 // Each pass through this loop does one read-exit episode. 3221 do { 3222 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of episode"); 3223 for (i = 0; i < read_exit_burst; i++) { 3224 if (READ_ONCE(read_exit_child_stop)) 3225 break; 3226 stutter_wait("rcu_torture_read_exit"); 3227 // Spawn child. 3228 tsp = kthread_run(rcu_torture_read_exit_child, 3229 &trs, "%s", "rcu_torture_read_exit_child"); 3230 if (IS_ERR(tsp)) { 3231 TOROUT_ERRSTRING("out of memory"); 3232 errexit = true; 3233 break; 3234 } 3235 cond_resched(); 3236 kthread_stop(tsp); 3237 n_read_exits++; 3238 } 3239 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: End of episode"); 3240 rcu_barrier(); // Wait for task_struct free, avoid OOM. 3241 i = 0; 3242 for (; !errexit && !READ_ONCE(read_exit_child_stop) && i < read_exit_delay; i++) 3243 schedule_timeout_uninterruptible(HZ); 3244 } while (!errexit && !READ_ONCE(read_exit_child_stop)); 3245 3246 // Clean up and exit. 3247 smp_store_release(&read_exit_child_stopped, true); // After reaping. 3248 smp_mb(); // Store before wakeup. 3249 wake_up(&read_exit_wq); 3250 while (!torture_must_stop()) 3251 schedule_timeout_uninterruptible(1); 3252 torture_kthread_stopping("rcu_torture_read_exit"); 3253 return 0; 3254 } 3255 rcu_torture_read_exit_init(void)3256 static int rcu_torture_read_exit_init(void) 3257 { 3258 if (read_exit_burst <= 0) 3259 return 0; 3260 init_waitqueue_head(&read_exit_wq); 3261 read_exit_child_stop = false; 3262 read_exit_child_stopped = false; 3263 return torture_create_kthread(rcu_torture_read_exit, NULL, 3264 read_exit_task); 3265 } 3266 rcu_torture_read_exit_cleanup(void)3267 static void rcu_torture_read_exit_cleanup(void) 3268 { 3269 if (!read_exit_task) 3270 return; 3271 WRITE_ONCE(read_exit_child_stop, true); 3272 smp_mb(); // Above write before wait. 3273 wait_event(read_exit_wq, smp_load_acquire(&read_exit_child_stopped)); 3274 torture_stop_kthread(rcutorture_read_exit, read_exit_task); 3275 } 3276 rcutorture_test_nmis(int n)3277 static void rcutorture_test_nmis(int n) 3278 { 3279 #if IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) 3280 int cpu; 3281 int dumpcpu; 3282 int i; 3283 3284 for (i = 0; i < n; i++) { 3285 preempt_disable(); 3286 cpu = smp_processor_id(); 3287 dumpcpu = cpu + 1; 3288 if (dumpcpu >= nr_cpu_ids) 3289 dumpcpu = 0; 3290 pr_alert("%s: CPU %d invoking dump_cpu_task(%d)\n", __func__, cpu, dumpcpu); 3291 dump_cpu_task(dumpcpu); 3292 preempt_enable(); 3293 schedule_timeout_uninterruptible(15 * HZ); 3294 } 3295 #else // #if IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) 3296 WARN_ONCE(n, "Non-zero rcutorture.test_nmis=%d permitted only when rcutorture is built in.\n", test_nmis); 3297 #endif // #else // #if IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) 3298 } 3299 3300 static enum cpuhp_state rcutor_hp; 3301 3302 static void rcu_torture_cleanup(void)3303 rcu_torture_cleanup(void) 3304 { 3305 int firsttime; 3306 int flags = 0; 3307 unsigned long gp_seq = 0; 3308 int i; 3309 3310 if (torture_cleanup_begin()) { 3311 if (cur_ops->cb_barrier != NULL) { 3312 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier); 3313 cur_ops->cb_barrier(); 3314 } 3315 rcu_gp_slow_unregister(NULL); 3316 return; 3317 } 3318 if (!cur_ops) { 3319 torture_cleanup_end(); 3320 rcu_gp_slow_unregister(NULL); 3321 return; 3322 } 3323 3324 rcutorture_test_nmis(test_nmis); 3325 3326 if (cur_ops->gp_kthread_dbg) 3327 cur_ops->gp_kthread_dbg(); 3328 rcu_torture_read_exit_cleanup(); 3329 rcu_torture_barrier_cleanup(); 3330 rcu_torture_fwd_prog_cleanup(); 3331 torture_stop_kthread(rcu_torture_stall, stall_task); 3332 torture_stop_kthread(rcu_torture_writer, writer_task); 3333 3334 if (nocb_tasks) { 3335 for (i = 0; i < nrealnocbers; i++) 3336 torture_stop_kthread(rcu_nocb_toggle, nocb_tasks[i]); 3337 kfree(nocb_tasks); 3338 nocb_tasks = NULL; 3339 } 3340 3341 if (reader_tasks) { 3342 for (i = 0; i < nrealreaders; i++) 3343 torture_stop_kthread(rcu_torture_reader, 3344 reader_tasks[i]); 3345 kfree(reader_tasks); 3346 reader_tasks = NULL; 3347 } 3348 kfree(rcu_torture_reader_mbchk); 3349 rcu_torture_reader_mbchk = NULL; 3350 3351 if (fakewriter_tasks) { 3352 for (i = 0; i < nfakewriters; i++) 3353 torture_stop_kthread(rcu_torture_fakewriter, 3354 fakewriter_tasks[i]); 3355 kfree(fakewriter_tasks); 3356 fakewriter_tasks = NULL; 3357 } 3358 3359 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq); 3360 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq); 3361 pr_alert("%s: End-test grace-period state: g%ld f%#x total-gps=%ld\n", 3362 cur_ops->name, (long)gp_seq, flags, 3363 rcutorture_seq_diff(gp_seq, start_gp_seq)); 3364 torture_stop_kthread(rcu_torture_stats, stats_task); 3365 torture_stop_kthread(rcu_torture_fqs, fqs_task); 3366 if (rcu_torture_can_boost() && rcutor_hp >= 0) 3367 cpuhp_remove_state(rcutor_hp); 3368 3369 /* 3370 * Wait for all RCU callbacks to fire, then do torture-type-specific 3371 * cleanup operations. 3372 */ 3373 if (cur_ops->cb_barrier != NULL) { 3374 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier); 3375 cur_ops->cb_barrier(); 3376 } 3377 if (cur_ops->cleanup != NULL) 3378 cur_ops->cleanup(); 3379 3380 rcu_torture_mem_dump_obj(); 3381 3382 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */ 3383 3384 if (err_segs_recorded) { 3385 pr_alert("Failure/close-call rcutorture reader segments:\n"); 3386 if (rt_read_nsegs == 0) 3387 pr_alert("\t: No segments recorded!!!\n"); 3388 firsttime = 1; 3389 for (i = 0; i < rt_read_nsegs; i++) { 3390 pr_alert("\t%d: %#x ", i, err_segs[i].rt_readstate); 3391 if (err_segs[i].rt_delay_jiffies != 0) { 3392 pr_cont("%s%ldjiffies", firsttime ? "" : "+", 3393 err_segs[i].rt_delay_jiffies); 3394 firsttime = 0; 3395 } 3396 if (err_segs[i].rt_delay_ms != 0) { 3397 pr_cont("%s%ldms", firsttime ? "" : "+", 3398 err_segs[i].rt_delay_ms); 3399 firsttime = 0; 3400 } 3401 if (err_segs[i].rt_delay_us != 0) { 3402 pr_cont("%s%ldus", firsttime ? "" : "+", 3403 err_segs[i].rt_delay_us); 3404 firsttime = 0; 3405 } 3406 pr_cont("%s\n", 3407 err_segs[i].rt_preempted ? "preempted" : ""); 3408 3409 } 3410 } 3411 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error) 3412 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE"); 3413 else if (torture_onoff_failures()) 3414 rcu_torture_print_module_parms(cur_ops, 3415 "End of test: RCU_HOTPLUG"); 3416 else 3417 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS"); 3418 torture_cleanup_end(); 3419 rcu_gp_slow_unregister(&rcu_fwd_cb_nodelay); 3420 } 3421 3422 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD rcu_torture_leak_cb(struct rcu_head * rhp)3423 static void rcu_torture_leak_cb(struct rcu_head *rhp) 3424 { 3425 } 3426 rcu_torture_err_cb(struct rcu_head * rhp)3427 static void rcu_torture_err_cb(struct rcu_head *rhp) 3428 { 3429 /* 3430 * This -might- happen due to race conditions, but is unlikely. 3431 * The scenario that leads to this happening is that the 3432 * first of the pair of duplicate callbacks is queued, 3433 * someone else starts a grace period that includes that 3434 * callback, then the second of the pair must wait for the 3435 * next grace period. Unlikely, but can happen. If it 3436 * does happen, the debug-objects subsystem won't have splatted. 3437 */ 3438 pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME); 3439 } 3440 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 3441 3442 /* 3443 * Verify that double-free causes debug-objects to complain, but only 3444 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test 3445 * cannot be carried out. 3446 */ rcu_test_debug_objects(void)3447 static void rcu_test_debug_objects(void) 3448 { 3449 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD 3450 struct rcu_head rh1; 3451 struct rcu_head rh2; 3452 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_KERNEL); 3453 3454 init_rcu_head_on_stack(&rh1); 3455 init_rcu_head_on_stack(&rh2); 3456 pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME); 3457 3458 /* Try to queue the rh2 pair of callbacks for the same grace period. */ 3459 preempt_disable(); /* Prevent preemption from interrupting test. */ 3460 rcu_read_lock(); /* Make it impossible to finish a grace period. */ 3461 call_rcu_hurry(&rh1, rcu_torture_leak_cb); /* Start grace period. */ 3462 local_irq_disable(); /* Make it harder to start a new grace period. */ 3463 call_rcu_hurry(&rh2, rcu_torture_leak_cb); 3464 call_rcu_hurry(&rh2, rcu_torture_err_cb); /* Duplicate callback. */ 3465 if (rhp) { 3466 call_rcu_hurry(rhp, rcu_torture_leak_cb); 3467 call_rcu_hurry(rhp, rcu_torture_err_cb); /* Another duplicate callback. */ 3468 } 3469 local_irq_enable(); 3470 rcu_read_unlock(); 3471 preempt_enable(); 3472 3473 /* Wait for them all to get done so we can safely return. */ 3474 rcu_barrier(); 3475 pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME); 3476 destroy_rcu_head_on_stack(&rh1); 3477 destroy_rcu_head_on_stack(&rh2); 3478 kfree(rhp); 3479 #else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 3480 pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME); 3481 #endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */ 3482 } 3483 rcutorture_sync(void)3484 static void rcutorture_sync(void) 3485 { 3486 static unsigned long n; 3487 3488 if (cur_ops->sync && !(++n & 0xfff)) 3489 cur_ops->sync(); 3490 } 3491 3492 static DEFINE_MUTEX(mut0); 3493 static DEFINE_MUTEX(mut1); 3494 static DEFINE_MUTEX(mut2); 3495 static DEFINE_MUTEX(mut3); 3496 static DEFINE_MUTEX(mut4); 3497 static DEFINE_MUTEX(mut5); 3498 static DEFINE_MUTEX(mut6); 3499 static DEFINE_MUTEX(mut7); 3500 static DEFINE_MUTEX(mut8); 3501 static DEFINE_MUTEX(mut9); 3502 3503 static DECLARE_RWSEM(rwsem0); 3504 static DECLARE_RWSEM(rwsem1); 3505 static DECLARE_RWSEM(rwsem2); 3506 static DECLARE_RWSEM(rwsem3); 3507 static DECLARE_RWSEM(rwsem4); 3508 static DECLARE_RWSEM(rwsem5); 3509 static DECLARE_RWSEM(rwsem6); 3510 static DECLARE_RWSEM(rwsem7); 3511 static DECLARE_RWSEM(rwsem8); 3512 static DECLARE_RWSEM(rwsem9); 3513 3514 DEFINE_STATIC_SRCU(srcu0); 3515 DEFINE_STATIC_SRCU(srcu1); 3516 DEFINE_STATIC_SRCU(srcu2); 3517 DEFINE_STATIC_SRCU(srcu3); 3518 DEFINE_STATIC_SRCU(srcu4); 3519 DEFINE_STATIC_SRCU(srcu5); 3520 DEFINE_STATIC_SRCU(srcu6); 3521 DEFINE_STATIC_SRCU(srcu7); 3522 DEFINE_STATIC_SRCU(srcu8); 3523 DEFINE_STATIC_SRCU(srcu9); 3524 srcu_lockdep_next(const char * f,const char * fl,const char * fs,const char * fu,int i,int cyclelen,int deadlock)3525 static int srcu_lockdep_next(const char *f, const char *fl, const char *fs, const char *fu, int i, 3526 int cyclelen, int deadlock) 3527 { 3528 int j = i + 1; 3529 3530 if (j >= cyclelen) 3531 j = deadlock ? 0 : -1; 3532 if (j >= 0) 3533 pr_info("%s: %s(%d), %s(%d), %s(%d)\n", f, fl, i, fs, j, fu, i); 3534 else 3535 pr_info("%s: %s(%d), %s(%d)\n", f, fl, i, fu, i); 3536 return j; 3537 } 3538 3539 // Test lockdep on SRCU-based deadlock scenarios. rcu_torture_init_srcu_lockdep(void)3540 static void rcu_torture_init_srcu_lockdep(void) 3541 { 3542 int cyclelen; 3543 int deadlock; 3544 bool err = false; 3545 int i; 3546 int j; 3547 int idx; 3548 struct mutex *muts[] = { &mut0, &mut1, &mut2, &mut3, &mut4, 3549 &mut5, &mut6, &mut7, &mut8, &mut9 }; 3550 struct rw_semaphore *rwsems[] = { &rwsem0, &rwsem1, &rwsem2, &rwsem3, &rwsem4, 3551 &rwsem5, &rwsem6, &rwsem7, &rwsem8, &rwsem9 }; 3552 struct srcu_struct *srcus[] = { &srcu0, &srcu1, &srcu2, &srcu3, &srcu4, 3553 &srcu5, &srcu6, &srcu7, &srcu8, &srcu9 }; 3554 int testtype; 3555 3556 if (!test_srcu_lockdep) 3557 return; 3558 3559 deadlock = test_srcu_lockdep / 1000; 3560 testtype = (test_srcu_lockdep / 10) % 100; 3561 cyclelen = test_srcu_lockdep % 10; 3562 WARN_ON_ONCE(ARRAY_SIZE(muts) != ARRAY_SIZE(srcus)); 3563 if (WARN_ONCE(deadlock != !!deadlock, 3564 "%s: test_srcu_lockdep=%d and deadlock digit %d must be zero or one.\n", 3565 __func__, test_srcu_lockdep, deadlock)) 3566 err = true; 3567 if (WARN_ONCE(cyclelen <= 0, 3568 "%s: test_srcu_lockdep=%d and cycle-length digit %d must be greater than zero.\n", 3569 __func__, test_srcu_lockdep, cyclelen)) 3570 err = true; 3571 if (err) 3572 goto err_out; 3573 3574 if (testtype == 0) { 3575 pr_info("%s: test_srcu_lockdep = %05d: SRCU %d-way %sdeadlock.\n", 3576 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-"); 3577 if (deadlock && cyclelen == 1) 3578 pr_info("%s: Expect hang.\n", __func__); 3579 for (i = 0; i < cyclelen; i++) { 3580 j = srcu_lockdep_next(__func__, "srcu_read_lock", "synchronize_srcu", 3581 "srcu_read_unlock", i, cyclelen, deadlock); 3582 idx = srcu_read_lock(srcus[i]); 3583 if (j >= 0) 3584 synchronize_srcu(srcus[j]); 3585 srcu_read_unlock(srcus[i], idx); 3586 } 3587 return; 3588 } 3589 3590 if (testtype == 1) { 3591 pr_info("%s: test_srcu_lockdep = %05d: SRCU/mutex %d-way %sdeadlock.\n", 3592 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-"); 3593 for (i = 0; i < cyclelen; i++) { 3594 pr_info("%s: srcu_read_lock(%d), mutex_lock(%d), mutex_unlock(%d), srcu_read_unlock(%d)\n", 3595 __func__, i, i, i, i); 3596 idx = srcu_read_lock(srcus[i]); 3597 mutex_lock(muts[i]); 3598 mutex_unlock(muts[i]); 3599 srcu_read_unlock(srcus[i], idx); 3600 3601 j = srcu_lockdep_next(__func__, "mutex_lock", "synchronize_srcu", 3602 "mutex_unlock", i, cyclelen, deadlock); 3603 mutex_lock(muts[i]); 3604 if (j >= 0) 3605 synchronize_srcu(srcus[j]); 3606 mutex_unlock(muts[i]); 3607 } 3608 return; 3609 } 3610 3611 if (testtype == 2) { 3612 pr_info("%s: test_srcu_lockdep = %05d: SRCU/rwsem %d-way %sdeadlock.\n", 3613 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-"); 3614 for (i = 0; i < cyclelen; i++) { 3615 pr_info("%s: srcu_read_lock(%d), down_read(%d), up_read(%d), srcu_read_unlock(%d)\n", 3616 __func__, i, i, i, i); 3617 idx = srcu_read_lock(srcus[i]); 3618 down_read(rwsems[i]); 3619 up_read(rwsems[i]); 3620 srcu_read_unlock(srcus[i], idx); 3621 3622 j = srcu_lockdep_next(__func__, "down_write", "synchronize_srcu", 3623 "up_write", i, cyclelen, deadlock); 3624 down_write(rwsems[i]); 3625 if (j >= 0) 3626 synchronize_srcu(srcus[j]); 3627 up_write(rwsems[i]); 3628 } 3629 return; 3630 } 3631 3632 #ifdef CONFIG_TASKS_TRACE_RCU 3633 if (testtype == 3) { 3634 pr_info("%s: test_srcu_lockdep = %05d: SRCU and Tasks Trace RCU %d-way %sdeadlock.\n", 3635 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-"); 3636 if (deadlock && cyclelen == 1) 3637 pr_info("%s: Expect hang.\n", __func__); 3638 for (i = 0; i < cyclelen; i++) { 3639 char *fl = i == 0 ? "rcu_read_lock_trace" : "srcu_read_lock"; 3640 char *fs = i == cyclelen - 1 ? "synchronize_rcu_tasks_trace" 3641 : "synchronize_srcu"; 3642 char *fu = i == 0 ? "rcu_read_unlock_trace" : "srcu_read_unlock"; 3643 3644 j = srcu_lockdep_next(__func__, fl, fs, fu, i, cyclelen, deadlock); 3645 if (i == 0) 3646 rcu_read_lock_trace(); 3647 else 3648 idx = srcu_read_lock(srcus[i]); 3649 if (j >= 0) { 3650 if (i == cyclelen - 1) 3651 synchronize_rcu_tasks_trace(); 3652 else 3653 synchronize_srcu(srcus[j]); 3654 } 3655 if (i == 0) 3656 rcu_read_unlock_trace(); 3657 else 3658 srcu_read_unlock(srcus[i], idx); 3659 } 3660 return; 3661 } 3662 #endif // #ifdef CONFIG_TASKS_TRACE_RCU 3663 3664 err_out: 3665 pr_info("%s: test_srcu_lockdep = %05d does nothing.\n", __func__, test_srcu_lockdep); 3666 pr_info("%s: test_srcu_lockdep = DNNL.\n", __func__); 3667 pr_info("%s: D: Deadlock if nonzero.\n", __func__); 3668 pr_info("%s: NN: Test number, 0=SRCU, 1=SRCU/mutex, 2=SRCU/rwsem, 3=SRCU/Tasks Trace RCU.\n", __func__); 3669 pr_info("%s: L: Cycle length.\n", __func__); 3670 if (!IS_ENABLED(CONFIG_TASKS_TRACE_RCU)) 3671 pr_info("%s: NN=3 disallowed because kernel is built with CONFIG_TASKS_TRACE_RCU=n\n", __func__); 3672 } 3673 3674 static int __init rcu_torture_init(void)3675 rcu_torture_init(void) 3676 { 3677 long i; 3678 int cpu; 3679 int firsterr = 0; 3680 int flags = 0; 3681 unsigned long gp_seq = 0; 3682 static struct rcu_torture_ops *torture_ops[] = { 3683 &rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops, &busted_srcud_ops, 3684 TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS 3685 &trivial_ops, 3686 }; 3687 3688 if (!torture_init_begin(torture_type, verbose)) 3689 return -EBUSY; 3690 3691 /* Process args and tell the world that the torturer is on the job. */ 3692 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) { 3693 cur_ops = torture_ops[i]; 3694 if (strcmp(torture_type, cur_ops->name) == 0) 3695 break; 3696 } 3697 if (i == ARRAY_SIZE(torture_ops)) { 3698 pr_alert("rcu-torture: invalid torture type: \"%s\"\n", 3699 torture_type); 3700 pr_alert("rcu-torture types:"); 3701 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) 3702 pr_cont(" %s", torture_ops[i]->name); 3703 pr_cont("\n"); 3704 firsterr = -EINVAL; 3705 cur_ops = NULL; 3706 goto unwind; 3707 } 3708 if (cur_ops->fqs == NULL && fqs_duration != 0) { 3709 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n"); 3710 fqs_duration = 0; 3711 } 3712 if (nocbs_nthreads != 0 && (cur_ops != &rcu_ops || 3713 !IS_ENABLED(CONFIG_RCU_NOCB_CPU))) { 3714 pr_alert("rcu-torture types: %s and CONFIG_RCU_NOCB_CPU=%d, nocb toggle disabled.\n", 3715 cur_ops->name, IS_ENABLED(CONFIG_RCU_NOCB_CPU)); 3716 nocbs_nthreads = 0; 3717 } 3718 if (cur_ops->init) 3719 cur_ops->init(); 3720 3721 rcu_torture_init_srcu_lockdep(); 3722 3723 if (nreaders >= 0) { 3724 nrealreaders = nreaders; 3725 } else { 3726 nrealreaders = num_online_cpus() - 2 - nreaders; 3727 if (nrealreaders <= 0) 3728 nrealreaders = 1; 3729 } 3730 rcu_torture_print_module_parms(cur_ops, "Start of test"); 3731 rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq); 3732 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq); 3733 start_gp_seq = gp_seq; 3734 pr_alert("%s: Start-test grace-period state: g%ld f%#x\n", 3735 cur_ops->name, (long)gp_seq, flags); 3736 3737 /* Set up the freelist. */ 3738 3739 INIT_LIST_HEAD(&rcu_torture_freelist); 3740 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) { 3741 rcu_tortures[i].rtort_mbtest = 0; 3742 list_add_tail(&rcu_tortures[i].rtort_free, 3743 &rcu_torture_freelist); 3744 } 3745 3746 /* Initialize the statistics so that each run gets its own numbers. */ 3747 3748 rcu_torture_current = NULL; 3749 rcu_torture_current_version = 0; 3750 atomic_set(&n_rcu_torture_alloc, 0); 3751 atomic_set(&n_rcu_torture_alloc_fail, 0); 3752 atomic_set(&n_rcu_torture_free, 0); 3753 atomic_set(&n_rcu_torture_mberror, 0); 3754 atomic_set(&n_rcu_torture_mbchk_fail, 0); 3755 atomic_set(&n_rcu_torture_mbchk_tries, 0); 3756 atomic_set(&n_rcu_torture_error, 0); 3757 n_rcu_torture_barrier_error = 0; 3758 n_rcu_torture_boost_ktrerror = 0; 3759 n_rcu_torture_boost_failure = 0; 3760 n_rcu_torture_boosts = 0; 3761 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) 3762 atomic_set(&rcu_torture_wcount[i], 0); 3763 for_each_possible_cpu(cpu) { 3764 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { 3765 per_cpu(rcu_torture_count, cpu)[i] = 0; 3766 per_cpu(rcu_torture_batch, cpu)[i] = 0; 3767 } 3768 } 3769 err_segs_recorded = 0; 3770 rt_read_nsegs = 0; 3771 3772 /* Start up the kthreads. */ 3773 3774 rcu_torture_write_types(); 3775 firsterr = torture_create_kthread(rcu_torture_writer, NULL, 3776 writer_task); 3777 if (torture_init_error(firsterr)) 3778 goto unwind; 3779 if (nfakewriters > 0) { 3780 fakewriter_tasks = kcalloc(nfakewriters, 3781 sizeof(fakewriter_tasks[0]), 3782 GFP_KERNEL); 3783 if (fakewriter_tasks == NULL) { 3784 TOROUT_ERRSTRING("out of memory"); 3785 firsterr = -ENOMEM; 3786 goto unwind; 3787 } 3788 } 3789 for (i = 0; i < nfakewriters; i++) { 3790 firsterr = torture_create_kthread(rcu_torture_fakewriter, 3791 NULL, fakewriter_tasks[i]); 3792 if (torture_init_error(firsterr)) 3793 goto unwind; 3794 } 3795 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]), 3796 GFP_KERNEL); 3797 rcu_torture_reader_mbchk = kcalloc(nrealreaders, sizeof(*rcu_torture_reader_mbchk), 3798 GFP_KERNEL); 3799 if (!reader_tasks || !rcu_torture_reader_mbchk) { 3800 TOROUT_ERRSTRING("out of memory"); 3801 firsterr = -ENOMEM; 3802 goto unwind; 3803 } 3804 for (i = 0; i < nrealreaders; i++) { 3805 rcu_torture_reader_mbchk[i].rtc_chkrdr = -1; 3806 firsterr = torture_create_kthread(rcu_torture_reader, (void *)i, 3807 reader_tasks[i]); 3808 if (torture_init_error(firsterr)) 3809 goto unwind; 3810 } 3811 nrealnocbers = nocbs_nthreads; 3812 if (WARN_ON(nrealnocbers < 0)) 3813 nrealnocbers = 1; 3814 if (WARN_ON(nocbs_toggle < 0)) 3815 nocbs_toggle = HZ; 3816 if (nrealnocbers > 0) { 3817 nocb_tasks = kcalloc(nrealnocbers, sizeof(nocb_tasks[0]), GFP_KERNEL); 3818 if (nocb_tasks == NULL) { 3819 TOROUT_ERRSTRING("out of memory"); 3820 firsterr = -ENOMEM; 3821 goto unwind; 3822 } 3823 } else { 3824 nocb_tasks = NULL; 3825 } 3826 for (i = 0; i < nrealnocbers; i++) { 3827 firsterr = torture_create_kthread(rcu_nocb_toggle, NULL, nocb_tasks[i]); 3828 if (torture_init_error(firsterr)) 3829 goto unwind; 3830 } 3831 if (stat_interval > 0) { 3832 firsterr = torture_create_kthread(rcu_torture_stats, NULL, 3833 stats_task); 3834 if (torture_init_error(firsterr)) 3835 goto unwind; 3836 } 3837 if (test_no_idle_hz && shuffle_interval > 0) { 3838 firsterr = torture_shuffle_init(shuffle_interval * HZ); 3839 if (torture_init_error(firsterr)) 3840 goto unwind; 3841 } 3842 if (stutter < 0) 3843 stutter = 0; 3844 if (stutter) { 3845 int t; 3846 3847 t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ; 3848 firsterr = torture_stutter_init(stutter * HZ, t); 3849 if (torture_init_error(firsterr)) 3850 goto unwind; 3851 } 3852 if (fqs_duration < 0) 3853 fqs_duration = 0; 3854 if (fqs_duration) { 3855 /* Create the fqs thread */ 3856 firsterr = torture_create_kthread(rcu_torture_fqs, NULL, 3857 fqs_task); 3858 if (torture_init_error(firsterr)) 3859 goto unwind; 3860 } 3861 if (test_boost_interval < 1) 3862 test_boost_interval = 1; 3863 if (test_boost_duration < 2) 3864 test_boost_duration = 2; 3865 if (rcu_torture_can_boost()) { 3866 3867 boost_starttime = jiffies + test_boost_interval * HZ; 3868 3869 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE", 3870 rcutorture_booster_init, 3871 rcutorture_booster_cleanup); 3872 rcutor_hp = firsterr; 3873 if (torture_init_error(firsterr)) 3874 goto unwind; 3875 } 3876 shutdown_jiffies = jiffies + shutdown_secs * HZ; 3877 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup); 3878 if (torture_init_error(firsterr)) 3879 goto unwind; 3880 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval, 3881 rcutorture_sync); 3882 if (torture_init_error(firsterr)) 3883 goto unwind; 3884 firsterr = rcu_torture_stall_init(); 3885 if (torture_init_error(firsterr)) 3886 goto unwind; 3887 firsterr = rcu_torture_fwd_prog_init(); 3888 if (torture_init_error(firsterr)) 3889 goto unwind; 3890 firsterr = rcu_torture_barrier_init(); 3891 if (torture_init_error(firsterr)) 3892 goto unwind; 3893 firsterr = rcu_torture_read_exit_init(); 3894 if (torture_init_error(firsterr)) 3895 goto unwind; 3896 if (object_debug) 3897 rcu_test_debug_objects(); 3898 torture_init_end(); 3899 rcu_gp_slow_register(&rcu_fwd_cb_nodelay); 3900 return 0; 3901 3902 unwind: 3903 torture_init_end(); 3904 rcu_torture_cleanup(); 3905 if (shutdown_secs) { 3906 WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST)); 3907 kernel_power_off(); 3908 } 3909 return firsterr; 3910 } 3911 3912 module_init(rcu_torture_init); 3913 module_exit(rcu_torture_cleanup); 3914