kernel/rcu/rcutorture.c

   1 /*
   2  * Read-Copy Update module-based torture test facility
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, you can access it online at
  16  * http://www.gnu.org/licenses/gpl-2.0.html.
  17  *
  18  * Copyright (C) IBM Corporation, 2005, 2006
  19  *
  20  * Authors: Paul E. McKenney <paulmck@us.ibm.com>
  21  *        Josh Triplett <josh@joshtriplett.org>
  22  *
  23  * See also:  Documentation/RCU/torture.txt
  24  */
  25 #include <linux/types.h>
  26 #include <linux/kernel.h>
  27 #include <linux/init.h>
  28 #include <linux/module.h>
  29 #include <linux/kthread.h>
  30 #include <linux/err.h>
  31 #include <linux/spinlock.h>
  32 #include <linux/smp.h>
  33 #include <linux/rcupdate.h>
  34 #include <linux/interrupt.h>
  35 #include <linux/sched/signal.h>
  36 #include <uapi/linux/sched/types.h>
  37 #include <linux/atomic.h>
  38 #include <linux/bitops.h>
  39 #include <linux/completion.h>
  40 #include <linux/moduleparam.h>
  41 #include <linux/percpu.h>
  42 #include <linux/notifier.h>
  43 #include <linux/reboot.h>
  44 #include <linux/freezer.h>
  45 #include <linux/cpu.h>
  46 #include <linux/delay.h>
  47 #include <linux/stat.h>
  48 #include <linux/srcu.h>
  49 #include <linux/slab.h>
  50 #include <linux/trace_clock.h>
  51 #include <asm/byteorder.h>
  52 #include <linux/torture.h>
  53 #include <linux/vmalloc.h>
  54 #include <linux/sched/debug.h>
  55
  56 #include "rcu.h"
  57
  58 MODULE_LICENSE("GPL");
  59 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
  60
  61
  62 torture_param(int, cbflood_inter_holdoff, HZ,
  63               "Holdoff between floods (jiffies)");
  64 torture_param(int, cbflood_intra_holdoff, 1,
  65               "Holdoff between bursts (jiffies)");
  66 torture_param(int, cbflood_n_burst, 3, "# bursts in flood, zero to disable");
  67 torture_param(int, cbflood_n_per_burst, 20000,
  68               "# callbacks per burst in flood");
  69 torture_param(int, fqs_duration, 0,
  70               "Duration of fqs bursts (us), 0 to disable");
  71 torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
  72 torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
  73 torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
  74 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
  75 torture_param(bool, gp_normal, false,
  76              "Use normal (non-expedited) GP wait primitives");
  77 torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
  78 torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
  79 torture_param(int, n_barrier_cbs, 0,
  80              "# of callbacks/kthreads for barrier testing");
  81 torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
  82 torture_param(int, nreaders, -1, "Number of RCU reader threads");
  83 torture_param(int, object_debug, 0,
  84              "Enable debug-object double call_rcu() testing");
  85 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
  86 torture_param(int, onoff_interval, 0,
  87              "Time between CPU hotplugs (s), 0=disable");
  88 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
  89 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
  90 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
  91 torture_param(int, stall_cpu_holdoff, 10,
  92              "Time to wait before starting stall (s).");
  93 torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling.");
  94 torture_param(int, stat_interval, 60,
  95              "Number of seconds between stats printk()s");
  96 torture_param(int, stutter, 5, "Number of seconds to run/halt test");
  97 torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
  98 torture_param(int, test_boost_duration, 4,
  99              "Duration of each boost test, seconds.");
 100 torture_param(int, test_boost_interval, 7,
 101              "Interval between boost tests, seconds.");
 102 torture_param(bool, test_no_idle_hz, true,
 103              "Test support for tickless idle CPUs");
 104 torture_param(bool, verbose, true,
 105              "Enable verbose debugging printk()s");
 106
 107 static char *torture_type = "rcu";
 108 module_param(torture_type, charp, 0444);
 109 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, ...)");
 110
 111 static int nrealreaders;
 112 static int ncbflooders;
 113 static struct task_struct *writer_task;
 114 static struct task_struct **fakewriter_tasks;
 115 static struct task_struct **reader_tasks;
 116 static struct task_struct *stats_task;
 117 static struct task_struct **cbflood_task;
 118 static struct task_struct *fqs_task;
 119 static struct task_struct *boost_tasks[NR_CPUS];
 120 static struct task_struct *stall_task;
 121 static struct task_struct **barrier_cbs_tasks;
 122 static struct task_struct *barrier_task;
 123
 124 #define RCU_TORTURE_PIPE_LEN 10
 125
 126 struct rcu_torture {
 127         struct rcu_head rtort_rcu;
 128         int rtort_pipe_count;
 129         struct list_head rtort_free;
 130         int rtort_mbtest;
 131 };
 132
 133 static LIST_HEAD(rcu_torture_freelist);
 134 static struct rcu_torture __rcu *rcu_torture_current;
 135 static unsigned long rcu_torture_current_version;
 136 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
 137 static DEFINE_SPINLOCK(rcu_torture_lock);
 138 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count);
 139 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch);
 140 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
 141 static atomic_t n_rcu_torture_alloc;
 142 static atomic_t n_rcu_torture_alloc_fail;
 143 static atomic_t n_rcu_torture_free;
 144 static atomic_t n_rcu_torture_mberror;
 145 static atomic_t n_rcu_torture_error;
 146 static long n_rcu_torture_barrier_error;
 147 static long n_rcu_torture_boost_ktrerror;
 148 static long n_rcu_torture_boost_rterror;
 149 static long n_rcu_torture_boost_failure;
 150 static long n_rcu_torture_boosts;
 151 static long n_rcu_torture_timers;
 152 static long n_barrier_attempts;
 153 static long n_barrier_successes;
 154 static atomic_long_t n_cbfloods;
 155 static struct list_head rcu_torture_removed;
 156
 157 static int rcu_torture_writer_state;
 158 #define RTWS_FIXED_DELAY        0
 159 #define RTWS_DELAY              1
 160 #define RTWS_REPLACE            2
 161 #define RTWS_DEF_FREE           3
 162 #define RTWS_EXP_SYNC           4
 163 #define RTWS_COND_GET           5
 164 #define RTWS_COND_SYNC          6
 165 #define RTWS_SYNC               7
 166 #define RTWS_STUTTER            8
 167 #define RTWS_STOPPING           9
 168 static const char * const rcu_torture_writer_state_names[] = {
 169         "RTWS_FIXED_DELAY",
 170         "RTWS_DELAY",
 171         "RTWS_REPLACE",
 172         "RTWS_DEF_FREE",
 173         "RTWS_EXP_SYNC",
 174         "RTWS_COND_GET",
 175         "RTWS_COND_SYNC",
 176         "RTWS_SYNC",
 177         "RTWS_STUTTER",
 178         "RTWS_STOPPING",
 179 };
 180
 181 static const char *rcu_torture_writer_state_getname(void)
 182 {
 183         unsigned int i = READ_ONCE(rcu_torture_writer_state);
 184
 185         if (i >= ARRAY_SIZE(rcu_torture_writer_state_names))
 186                 return "???";
 187         return rcu_torture_writer_state_names[i];
 188 }
 189
 190 #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
 191 #define rcu_can_boost() 1
 192 #else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
 193 #define rcu_can_boost() 0
 194 #endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
 195
 196 #ifdef CONFIG_RCU_TRACE
 197 static u64 notrace rcu_trace_clock_local(void)
 198 {
 199         u64 ts = trace_clock_local();
 200
 201         (void)do_div(ts, NSEC_PER_USEC);
 202         return ts;
 203 }
 204 #else /* #ifdef CONFIG_RCU_TRACE */
 205 static u64 notrace rcu_trace_clock_local(void)
 206 {
 207         return 0ULL;
 208 }
 209 #endif /* #else #ifdef CONFIG_RCU_TRACE */
 210
 211 static unsigned long boost_starttime;   /* jiffies of next boost test start. */
 212 static DEFINE_MUTEX(boost_mutex);       /* protect setting boost_starttime */
 213                                         /*  and boost task create/destroy. */
 214 static atomic_t barrier_cbs_count;      /* Barrier callbacks registered. */
 215 static bool barrier_phase;              /* Test phase. */
 216 static atomic_t barrier_cbs_invoked;    /* Barrier callbacks invoked. */
 217 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
 218 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
 219
 220 /*
 221  * Allocate an element from the rcu_tortures pool.
 222  */
 223 static struct rcu_torture *
 224 rcu_torture_alloc(void)
 225 {
 226         struct list_head *p;
 227
 228         spin_lock_bh(&rcu_torture_lock);
 229         if (list_empty(&rcu_torture_freelist)) {
 230                 atomic_inc(&n_rcu_torture_alloc_fail);
 231                 spin_unlock_bh(&rcu_torture_lock);
 232                 return NULL;
 233         }
 234         atomic_inc(&n_rcu_torture_alloc);
 235         p = rcu_torture_freelist.next;
 236         list_del_init(p);
 237         spin_unlock_bh(&rcu_torture_lock);
 238         return container_of(p, struct rcu_torture, rtort_free);
 239 }
 240
 241 /*
 242  * Free an element to the rcu_tortures pool.
 243  */
 244 static void
 245 rcu_torture_free(struct rcu_torture *p)
 246 {
 247         atomic_inc(&n_rcu_torture_free);
 248         spin_lock_bh(&rcu_torture_lock);
 249         list_add_tail(&p->rtort_free, &rcu_torture_freelist);
 250         spin_unlock_bh(&rcu_torture_lock);
 251 }
 252
 253 /*
 254  * Operations vector for selecting different types of tests.
 255  */
 256
 257 struct rcu_torture_ops {
 258         int ttype;
 259         void (*init)(void);
 260         void (*cleanup)(void);
 261         int (*readlock)(void);
 262         void (*read_delay)(struct torture_random_state *rrsp);
 263         void (*readunlock)(int idx);
 264         unsigned long (*started)(void);
 265         unsigned long (*completed)(void);
 266         void (*deferred_free)(struct rcu_torture *p);
 267         void (*sync)(void);
 268         void (*exp_sync)(void);
 269         unsigned long (*get_state)(void);
 270         void (*cond_sync)(unsigned long oldstate);
 271         call_rcu_func_t call;
 272         void (*cb_barrier)(void);
 273         void (*fqs)(void);
 274         void (*stats)(void);
 275         int irq_capable;
 276         int can_boost;
 277         const char *name;
 278 };
 279
 280 static struct rcu_torture_ops *cur_ops;
 281
 282 /*
 283  * Definitions for rcu torture testing.
 284  */
 285
 286 static int rcu_torture_read_lock(void) __acquires(RCU)
 287 {
 288         rcu_read_lock();
 289         return 0;
 290 }
 291
 292 static void rcu_read_delay(struct torture_random_state *rrsp)
 293 {
 294         unsigned long started;
 295         unsigned long completed;
 296         const unsigned long shortdelay_us = 200;
 297         const unsigned long longdelay_ms = 50;
 298         unsigned long long ts;
 299
 300         /* We want a short delay sometimes to make a reader delay the grace
 301          * period, and we want a long delay occasionally to trigger
 302          * force_quiescent_state. */
 303
 304         if (!(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) {
 305                 started = cur_ops->completed();
 306                 ts = rcu_trace_clock_local();
 307                 mdelay(longdelay_ms);
 308                 completed = cur_ops->completed();
 309                 do_trace_rcu_torture_read(cur_ops->name, NULL, ts,
 310                                           started, completed);
 311         }
 312         if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
 313                 udelay(shortdelay_us);
 314         if (!preempt_count() &&
 315             !(torture_random(rrsp) % (nrealreaders * 500)))
 316                 torture_preempt_schedule();  /* QS only if preemptible. */
 317 }
 318
 319 static void rcu_torture_read_unlock(int idx) __releases(RCU)
 320 {
 321         rcu_read_unlock();
 322 }
 323
 324 /*
 325  * Update callback in the pipe.  This should be invoked after a grace period.
 326  */
 327 static bool
 328 rcu_torture_pipe_update_one(struct rcu_torture *rp)
 329 {
 330         int i;
 331
 332         i = rp->rtort_pipe_count;
 333         if (i > RCU_TORTURE_PIPE_LEN)
 334                 i = RCU_TORTURE_PIPE_LEN;
 335         atomic_inc(&rcu_torture_wcount[i]);
 336         if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
 337                 rp->rtort_mbtest = 0;
 338                 return true;
 339         }
 340         return false;
 341 }
 342
 343 /*
 344  * Update all callbacks in the pipe.  Suitable for synchronous grace-period
 345  * primitives.
 346  */
 347 static void
 348 rcu_torture_pipe_update(struct rcu_torture *old_rp)
 349 {
 350         struct rcu_torture *rp;
 351         struct rcu_torture *rp1;
 352
 353         if (old_rp)
 354                 list_add(&old_rp->rtort_free, &rcu_torture_removed);
 355         list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
 356                 if (rcu_torture_pipe_update_one(rp)) {
 357                         list_del(&rp->rtort_free);
 358                         rcu_torture_free(rp);
 359                 }
 360         }
 361 }
 362
 363 static void
 364 rcu_torture_cb(struct rcu_head *p)
 365 {
 366         struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
 367
 368         if (torture_must_stop_irq()) {
 369                 /* Test is ending, just drop callbacks on the floor. */
 370                 /* The next initialization will pick up the pieces. */
 371                 return;
 372         }
 373         if (rcu_torture_pipe_update_one(rp))
 374                 rcu_torture_free(rp);
 375         else
 376                 cur_ops->deferred_free(rp);
 377 }
 378
 379 static unsigned long rcu_no_completed(void)
 380 {
 381         return 0;
 382 }
 383
 384 static void rcu_torture_deferred_free(struct rcu_torture *p)
 385 {
 386         call_rcu(&p->rtort_rcu, rcu_torture_cb);
 387 }
 388
 389 static void rcu_sync_torture_init(void)
 390 {
 391         INIT_LIST_HEAD(&rcu_torture_removed);
 392 }
 393
 394 static struct rcu_torture_ops rcu_ops = {
 395         .ttype          = RCU_FLAVOR,
 396         .init           = rcu_sync_torture_init,
 397         .readlock       = rcu_torture_read_lock,
 398         .read_delay     = rcu_read_delay,
 399         .readunlock     = rcu_torture_read_unlock,
 400         .started        = rcu_batches_started,
 401         .completed      = rcu_batches_completed,
 402         .deferred_free  = rcu_torture_deferred_free,
 403         .sync           = synchronize_rcu,
 404         .exp_sync       = synchronize_rcu_expedited,
 405         .get_state      = get_state_synchronize_rcu,
 406         .cond_sync      = cond_synchronize_rcu,
 407         .call           = call_rcu,
 408         .cb_barrier     = rcu_barrier,
 409         .fqs            = rcu_force_quiescent_state,
 410         .stats          = NULL,
 411         .irq_capable    = 1,
 412         .can_boost      = rcu_can_boost(),
 413         .name           = "rcu"
 414 };
 415
 416 /*
 417  * Definitions for rcu_bh torture testing.
 418  */
 419
 420 static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
 421 {
 422         rcu_read_lock_bh();
 423         return 0;
 424 }
 425
 426 static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
 427 {
 428         rcu_read_unlock_bh();
 429 }
 430
 431 static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
 432 {
 433         call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
 434 }
 435
 436 static struct rcu_torture_ops rcu_bh_ops = {
 437         .ttype          = RCU_BH_FLAVOR,
 438         .init           = rcu_sync_torture_init,
 439         .readlock       = rcu_bh_torture_read_lock,
 440         .read_delay     = rcu_read_delay,  /* just reuse rcu's version. */
 441         .readunlock     = rcu_bh_torture_read_unlock,
 442         .started        = rcu_batches_started_bh,
 443         .completed      = rcu_batches_completed_bh,
 444         .deferred_free  = rcu_bh_torture_deferred_free,
 445         .sync           = synchronize_rcu_bh,
 446         .exp_sync       = synchronize_rcu_bh_expedited,
 447         .call           = call_rcu_bh,
 448         .cb_barrier     = rcu_barrier_bh,
 449         .fqs            = rcu_bh_force_quiescent_state,
 450         .stats          = NULL,
 451         .irq_capable    = 1,
 452         .name           = "rcu_bh"
 453 };
 454
 455 /*
 456  * Don't even think about trying any of these in real life!!!
 457  * The names includes "busted", and they really means it!
 458  * The only purpose of these functions is to provide a buggy RCU
 459  * implementation to make sure that rcutorture correctly emits
 460  * buggy-RCU error messages.
 461  */
 462 static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
 463 {
 464         /* This is a deliberate bug for testing purposes only! */
 465         rcu_torture_cb(&p->rtort_rcu);
 466 }
 467
 468 static void synchronize_rcu_busted(void)
 469 {
 470         /* This is a deliberate bug for testing purposes only! */
 471 }
 472
 473 static void
 474 call_rcu_busted(struct rcu_head *head, rcu_callback_t func)
 475 {
 476         /* This is a deliberate bug for testing purposes only! */
 477         func(head);
 478 }
 479
 480 static struct rcu_torture_ops rcu_busted_ops = {
 481         .ttype          = INVALID_RCU_FLAVOR,
 482         .init           = rcu_sync_torture_init,
 483         .readlock       = rcu_torture_read_lock,
 484         .read_delay     = rcu_read_delay,  /* just reuse rcu's version. */
 485         .readunlock     = rcu_torture_read_unlock,
 486         .started        = rcu_no_completed,
 487         .completed      = rcu_no_completed,
 488         .deferred_free  = rcu_busted_torture_deferred_free,
 489         .sync           = synchronize_rcu_busted,
 490         .exp_sync       = synchronize_rcu_busted,
 491         .call           = call_rcu_busted,
 492         .cb_barrier     = NULL,
 493         .fqs            = NULL,
 494         .stats          = NULL,
 495         .irq_capable    = 1,
 496         .name           = "busted"
 497 };
 498
 499 /*
 500  * Definitions for srcu torture testing.
 501  */
 502
 503 DEFINE_STATIC_SRCU(srcu_ctl);
 504 static struct srcu_struct srcu_ctld;
 505 static struct srcu_struct *srcu_ctlp = &srcu_ctl;
 506
 507 static int srcu_torture_read_lock(void) __acquires(srcu_ctlp)
 508 {
 509         return srcu_read_lock(srcu_ctlp);
 510 }
 511
 512 static void srcu_read_delay(struct torture_random_state *rrsp)
 513 {
 514         long delay;
 515         const long uspertick = 1000000 / HZ;
 516         const long longdelay = 10;
 517
 518         /* We want there to be long-running readers, but not all the time. */
 519
 520         delay = torture_random(rrsp) %
 521                 (nrealreaders * 2 * longdelay * uspertick);
 522         if (!delay && in_task())
 523                 schedule_timeout_interruptible(longdelay);
 524         else
 525                 rcu_read_delay(rrsp);
 526 }
 527
 528 static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp)
 529 {
 530         srcu_read_unlock(srcu_ctlp, idx);
 531 }
 532
 533 static unsigned long srcu_torture_completed(void)
 534 {
 535         return srcu_batches_completed(srcu_ctlp);
 536 }
 537
 538 static void srcu_torture_deferred_free(struct rcu_torture *rp)
 539 {
 540         call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
 541 }
 542
 543 static void srcu_torture_synchronize(void)
 544 {
 545         synchronize_srcu(srcu_ctlp);
 546 }
 547
 548 static void srcu_torture_call(struct rcu_head *head,
 549                               rcu_callback_t func)
 550 {
 551         call_srcu(srcu_ctlp, head, func);
 552 }
 553
 554 static void srcu_torture_barrier(void)
 555 {
 556         srcu_barrier(srcu_ctlp);
 557 }
 558
 559 static void srcu_torture_stats(void)
 560 {
 561         srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG);
 562 }
 563
 564 static void srcu_torture_synchronize_expedited(void)
 565 {
 566         synchronize_srcu_expedited(srcu_ctlp);
 567 }
 568
 569 static struct rcu_torture_ops srcu_ops = {
 570         .ttype          = SRCU_FLAVOR,
 571         .init           = rcu_sync_torture_init,
 572         .readlock       = srcu_torture_read_lock,
 573         .read_delay     = srcu_read_delay,
 574         .readunlock     = srcu_torture_read_unlock,
 575         .started        = NULL,
 576         .completed      = srcu_torture_completed,
 577         .deferred_free  = srcu_torture_deferred_free,
 578         .sync           = srcu_torture_synchronize,
 579         .exp_sync       = srcu_torture_synchronize_expedited,
 580         .call           = srcu_torture_call,
 581         .cb_barrier     = srcu_torture_barrier,
 582         .stats          = srcu_torture_stats,
 583         .irq_capable    = 1,
 584         .name           = "srcu"
 585 };
 586
 587 static void srcu_torture_init(void)
 588 {
 589         rcu_sync_torture_init();
 590         WARN_ON(init_srcu_struct(&srcu_ctld));
 591         srcu_ctlp = &srcu_ctld;
 592 }
 593
 594 static void srcu_torture_cleanup(void)
 595 {
 596         static DEFINE_TORTURE_RANDOM(rand);
 597
 598         if (torture_random(&rand) & 0x800)
 599                 cleanup_srcu_struct(&srcu_ctld);
 600         else
 601                 cleanup_srcu_struct_quiesced(&srcu_ctld);
 602         srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
 603 }
 604
 605 /* As above, but dynamically allocated. */
 606 static struct rcu_torture_ops srcud_ops = {
 607         .ttype          = SRCU_FLAVOR,
 608         .init           = srcu_torture_init,
 609         .cleanup        = srcu_torture_cleanup,
 610         .readlock       = srcu_torture_read_lock,
 611         .read_delay     = srcu_read_delay,
 612         .readunlock     = srcu_torture_read_unlock,
 613         .started        = NULL,
 614         .completed      = srcu_torture_completed,
 615         .deferred_free  = srcu_torture_deferred_free,
 616         .sync           = srcu_torture_synchronize,
 617         .exp_sync       = srcu_torture_synchronize_expedited,
 618         .call           = srcu_torture_call,
 619         .cb_barrier     = srcu_torture_barrier,
 620         .stats          = srcu_torture_stats,
 621         .irq_capable    = 1,
 622         .name           = "srcud"
 623 };
 624
 625 /*
 626  * Definitions for sched torture testing.
 627  */
 628
 629 static int sched_torture_read_lock(void)
 630 {
 631         preempt_disable();
 632         return 0;
 633 }
 634
 635 static void sched_torture_read_unlock(int idx)
 636 {
 637         preempt_enable();
 638 }
 639
 640 static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
 641 {
 642         call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
 643 }
 644
 645 static struct rcu_torture_ops sched_ops = {
 646         .ttype          = RCU_SCHED_FLAVOR,
 647         .init           = rcu_sync_torture_init,
 648         .readlock       = sched_torture_read_lock,
 649         .read_delay     = rcu_read_delay,  /* just reuse rcu's version. */
 650         .readunlock     = sched_torture_read_unlock,
 651         .started        = rcu_batches_started_sched,
 652         .completed      = rcu_batches_completed_sched,
 653         .deferred_free  = rcu_sched_torture_deferred_free,
 654         .sync           = synchronize_sched,
 655         .exp_sync       = synchronize_sched_expedited,
 656         .get_state      = get_state_synchronize_sched,
 657         .cond_sync      = cond_synchronize_sched,
 658         .call           = call_rcu_sched,
 659         .cb_barrier     = rcu_barrier_sched,
 660         .fqs            = rcu_sched_force_quiescent_state,
 661         .stats          = NULL,
 662         .irq_capable    = 1,
 663         .name           = "sched"
 664 };
 665
 666 /*
 667  * Definitions for RCU-tasks torture testing.
 668  */
 669
 670 static int tasks_torture_read_lock(void)
 671 {
 672         return 0;
 673 }
 674
 675 static void tasks_torture_read_unlock(int idx)
 676 {
 677 }
 678
 679 static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
 680 {
 681         call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
 682 }
 683
 684 static struct rcu_torture_ops tasks_ops = {
 685         .ttype          = RCU_TASKS_FLAVOR,
 686         .init           = rcu_sync_torture_init,
 687         .readlock       = tasks_torture_read_lock,
 688         .read_delay     = rcu_read_delay,  /* just reuse rcu's version. */
 689         .readunlock     = tasks_torture_read_unlock,
 690         .started        = rcu_no_completed,
 691         .completed      = rcu_no_completed,
 692         .deferred_free  = rcu_tasks_torture_deferred_free,
 693         .sync           = synchronize_rcu_tasks,
 694         .exp_sync       = synchronize_rcu_tasks,
 695         .call           = call_rcu_tasks,
 696         .cb_barrier     = rcu_barrier_tasks,
 697         .fqs            = NULL,
 698         .stats          = NULL,
 699         .irq_capable    = 1,
 700         .name           = "tasks"
 701 };
 702
 703 static bool __maybe_unused torturing_tasks(void)
 704 {
 705         return cur_ops == &tasks_ops;
 706 }
 707
 708 /*
 709  * RCU torture priority-boost testing.  Runs one real-time thread per
 710  * CPU for moderate bursts, repeatedly registering RCU callbacks and
 711  * spinning waiting for them to be invoked.  If a given callback takes
 712  * too long to be invoked, we assume that priority inversion has occurred.
 713  */
 714
 715 struct rcu_boost_inflight {
 716         struct rcu_head rcu;
 717         int inflight;
 718 };
 719
 720 static void rcu_torture_boost_cb(struct rcu_head *head)
 721 {
 722         struct rcu_boost_inflight *rbip =
 723                 container_of(head, struct rcu_boost_inflight, rcu);
 724
 725         /* Ensure RCU-core accesses precede clearing ->inflight */
 726         smp_store_release(&rbip->inflight, 0);
 727 }
 728
 729 static int rcu_torture_boost(void *arg)
 730 {
 731         unsigned long call_rcu_time;
 732         unsigned long endtime;
 733         unsigned long oldstarttime;
 734         struct rcu_boost_inflight rbi = { .inflight = 0 };
 735         struct sched_param sp;
 736
 737         VERBOSE_TOROUT_STRING("rcu_torture_boost started");
 738
 739         /* Set real-time priority. */
 740         sp.sched_priority = 1;
 741         if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
 742                 VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!");
 743                 n_rcu_torture_boost_rterror++;
 744         }
 745
 746         init_rcu_head_on_stack(&rbi.rcu);
 747         /* Each pass through the following loop does one boost-test cycle. */
 748         do {
 749                 /* Wait for the next test interval. */
 750                 oldstarttime = boost_starttime;
 751                 while (ULONG_CMP_LT(jiffies, oldstarttime)) {
 752                         schedule_timeout_interruptible(oldstarttime - jiffies);
 753                         stutter_wait("rcu_torture_boost");
 754                         if (torture_must_stop())
 755                                 goto checkwait;
 756                 }
 757
 758                 /* Do one boost-test interval. */
 759                 endtime = oldstarttime + test_boost_duration * HZ;
 760                 call_rcu_time = jiffies;
 761                 while (ULONG_CMP_LT(jiffies, endtime)) {
 762                         /* If we don't have a callback in flight, post one. */
 763                         if (!smp_load_acquire(&rbi.inflight)) {
 764                                 /* RCU core before ->inflight = 1. */
 765                                 smp_store_release(&rbi.inflight, 1);
 766                                 call_rcu(&rbi.rcu, rcu_torture_boost_cb);
 767                                 if (jiffies - call_rcu_time >
 768                                          test_boost_duration * HZ - HZ / 2) {
 769                                         VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
 770                                         n_rcu_torture_boost_failure++;
 771                                 }
 772                                 call_rcu_time = jiffies;
 773                         }
 774                         stutter_wait("rcu_torture_boost");
 775                         if (torture_must_stop())
 776                                 goto checkwait;
 777                 }
 778
 779                 /*
 780                  * Set the start time of the next test interval.
 781                  * Yes, this is vulnerable to long delays, but such
 782                  * delays simply cause a false negative for the next
 783                  * interval.  Besides, we are running at RT priority,
 784                  * so delays should be relatively rare.
 785                  */
 786                 while (oldstarttime == boost_starttime &&
 787                        !kthread_should_stop()) {
 788                         if (mutex_trylock(&boost_mutex)) {
 789                                 boost_starttime = jiffies +
 790                                                   test_boost_interval * HZ;
 791                                 n_rcu_torture_boosts++;
 792                                 mutex_unlock(&boost_mutex);
 793                                 break;
 794                         }
 795                         schedule_timeout_uninterruptible(1);
 796                 }
 797
 798                 /* Go do the stutter. */
 799 checkwait:      stutter_wait("rcu_torture_boost");
 800         } while (!torture_must_stop());
 801
 802         /* Clean up and exit. */
 803         while (!kthread_should_stop() || smp_load_acquire(&rbi.inflight)) {
 804                 torture_shutdown_absorb("rcu_torture_boost");
 805                 schedule_timeout_uninterruptible(1);
 806         }
 807         destroy_rcu_head_on_stack(&rbi.rcu);
 808         torture_kthread_stopping("rcu_torture_boost");
 809         return 0;
 810 }
 811
 812 static void rcu_torture_cbflood_cb(struct rcu_head *rhp)
 813 {
 814 }
 815
 816 /*
 817  * RCU torture callback-flood kthread.  Repeatedly induces bursts of calls
 818  * to call_rcu() or analogous, increasing the probability of occurrence
 819  * of callback-overflow corner cases.
 820  */
 821 static int
 822 rcu_torture_cbflood(void *arg)
 823 {
 824         int err = 1;
 825         int i;
 826         int j;
 827         struct rcu_head *rhp;
 828
 829         if (cbflood_n_per_burst > 0 &&
 830             cbflood_inter_holdoff > 0 &&
 831             cbflood_intra_holdoff > 0 &&
 832             cur_ops->call &&
 833             cur_ops->cb_barrier) {
 834                 rhp = vmalloc(array3_size(cbflood_n_burst,
 835                                           cbflood_n_per_burst,
 836                                           sizeof(*rhp)));
 837                 err = !rhp;
 838         }
 839         if (err) {
 840                 VERBOSE_TOROUT_STRING("rcu_torture_cbflood disabled: Bad args or OOM");
 841                 goto wait_for_stop;
 842         }
 843         VERBOSE_TOROUT_STRING("rcu_torture_cbflood task started");
 844         do {
 845                 schedule_timeout_interruptible(cbflood_inter_holdoff);
 846                 atomic_long_inc(&n_cbfloods);
 847                 WARN_ON(signal_pending(current));
 848                 for (i = 0; i < cbflood_n_burst; i++) {
 849                         for (j = 0; j < cbflood_n_per_burst; j++) {
 850                                 cur_ops->call(&rhp[i * cbflood_n_per_burst + j],
 851                                               rcu_torture_cbflood_cb);
 852                         }
 853                         schedule_timeout_interruptible(cbflood_intra_holdoff);
 854                         WARN_ON(signal_pending(current));
 855                 }
 856                 cur_ops->cb_barrier();
 857                 stutter_wait("rcu_torture_cbflood");
 858         } while (!torture_must_stop());
 859         vfree(rhp);
 860 wait_for_stop:
 861         torture_kthread_stopping("rcu_torture_cbflood");
 862         return 0;
 863 }
 864
 865 /*
 866  * RCU torture force-quiescent-state kthread.  Repeatedly induces
 867  * bursts of calls to force_quiescent_state(), increasing the probability
 868  * of occurrence of some important types of race conditions.
 869  */
 870 static int
 871 rcu_torture_fqs(void *arg)
 872 {
 873         unsigned long fqs_resume_time;
 874         int fqs_burst_remaining;
 875
 876         VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
 877         do {
 878                 fqs_resume_time = jiffies + fqs_stutter * HZ;
 879                 while (ULONG_CMP_LT(jiffies, fqs_resume_time) &&
 880                        !kthread_should_stop()) {
 881                         schedule_timeout_interruptible(1);
 882                 }
 883                 fqs_burst_remaining = fqs_duration;
 884                 while (fqs_burst_remaining > 0 &&
 885                        !kthread_should_stop()) {
 886                         cur_ops->fqs();
 887                         udelay(fqs_holdoff);
 888                         fqs_burst_remaining -= fqs_holdoff;
 889                 }
 890                 stutter_wait("rcu_torture_fqs");
 891         } while (!torture_must_stop());
 892         torture_kthread_stopping("rcu_torture_fqs");
 893         return 0;
 894 }
 895
 896 /*
 897  * RCU torture writer kthread.  Repeatedly substitutes a new structure
 898  * for that pointed to by rcu_torture_current, freeing the old structure
 899  * after a series of grace periods (the "pipeline").
 900  */
 901 static int
 902 rcu_torture_writer(void *arg)
 903 {
 904         bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
 905         int expediting = 0;
 906         unsigned long gp_snap;
 907         bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal;
 908         bool gp_sync1 = gp_sync;
 909         int i;
 910         struct rcu_torture *rp;
 911         struct rcu_torture *old_rp;
 912         static DEFINE_TORTURE_RANDOM(rand);
 913         int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC,
 914                            RTWS_COND_GET, RTWS_SYNC };
 915         int nsynctypes = 0;
 916
 917         VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
 918         if (!can_expedite)
 919                 pr_alert("%s" TORTURE_FLAG
 920                          " GP expediting controlled from boot/sysfs for %s.\n",
 921                          torture_type, cur_ops->name);
 922
 923         /* Initialize synctype[] array.  If none set, take default. */
 924         if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync1)
 925                 gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true;
 926         if (gp_cond1 && cur_ops->get_state && cur_ops->cond_sync) {
 927                 synctype[nsynctypes++] = RTWS_COND_GET;
 928                 pr_info("%s: Testing conditional GPs.\n", __func__);
 929         } else if (gp_cond && (!cur_ops->get_state || !cur_ops->cond_sync)) {
 930                 pr_alert("%s: gp_cond without primitives.\n", __func__);
 931         }
 932         if (gp_exp1 && cur_ops->exp_sync) {
 933                 synctype[nsynctypes++] = RTWS_EXP_SYNC;
 934                 pr_info("%s: Testing expedited GPs.\n", __func__);
 935         } else if (gp_exp && !cur_ops->exp_sync) {
 936                 pr_alert("%s: gp_exp without primitives.\n", __func__);
 937         }
 938         if (gp_normal1 && cur_ops->deferred_free) {
 939                 synctype[nsynctypes++] = RTWS_DEF_FREE;
 940                 pr_info("%s: Testing asynchronous GPs.\n", __func__);
 941         } else if (gp_normal && !cur_ops->deferred_free) {
 942                 pr_alert("%s: gp_normal without primitives.\n", __func__);
 943         }
 944         if (gp_sync1 && cur_ops->sync) {
 945                 synctype[nsynctypes++] = RTWS_SYNC;
 946                 pr_info("%s: Testing normal GPs.\n", __func__);
 947         } else if (gp_sync && !cur_ops->sync) {
 948                 pr_alert("%s: gp_sync without primitives.\n", __func__);
 949         }
 950         if (WARN_ONCE(nsynctypes == 0,
 951                       "rcu_torture_writer: No update-side primitives.\n")) {
 952                 /*
 953                  * No updates primitives, so don't try updating.
 954                  * The resulting test won't be testing much, hence the
 955                  * above WARN_ONCE().
 956                  */
 957                 rcu_torture_writer_state = RTWS_STOPPING;
 958                 torture_kthread_stopping("rcu_torture_writer");
 959         }
 960
 961         do {
 962                 rcu_torture_writer_state = RTWS_FIXED_DELAY;
 963                 schedule_timeout_uninterruptible(1);
 964                 rp = rcu_torture_alloc();
 965                 if (rp == NULL)
 966                         continue;
 967                 rp->rtort_pipe_count = 0;
 968                 rcu_torture_writer_state = RTWS_DELAY;
 969                 udelay(torture_random(&rand) & 0x3ff);
 970                 rcu_torture_writer_state = RTWS_REPLACE;
 971                 old_rp = rcu_dereference_check(rcu_torture_current,
 972                                                current == writer_task);
 973                 rp->rtort_mbtest = 1;
 974                 rcu_assign_pointer(rcu_torture_current, rp);
 975                 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
 976                 if (old_rp) {
 977                         i = old_rp->rtort_pipe_count;
 978                         if (i > RCU_TORTURE_PIPE_LEN)
 979                                 i = RCU_TORTURE_PIPE_LEN;
 980                         atomic_inc(&rcu_torture_wcount[i]);
 981                         old_rp->rtort_pipe_count++;
 982                         switch (synctype[torture_random(&rand) % nsynctypes]) {
 983                         case RTWS_DEF_FREE:
 984                                 rcu_torture_writer_state = RTWS_DEF_FREE;
 985                                 cur_ops->deferred_free(old_rp);
 986                                 break;
 987                         case RTWS_EXP_SYNC:
 988                                 rcu_torture_writer_state = RTWS_EXP_SYNC;
 989                                 cur_ops->exp_sync();
 990                                 rcu_torture_pipe_update(old_rp);
 991                                 break;
 992                         case RTWS_COND_GET:
 993                                 rcu_torture_writer_state = RTWS_COND_GET;
 994                                 gp_snap = cur_ops->get_state();
 995                                 i = torture_random(&rand) % 16;
 996                                 if (i != 0)
 997                                         schedule_timeout_interruptible(i);
 998                                 udelay(torture_random(&rand) % 1000);
 999                                 rcu_torture_writer_state = RTWS_COND_SYNC;
1000                                 cur_ops->cond_sync(gp_snap);
1001                                 rcu_torture_pipe_update(old_rp);
1002                                 break;
1003                         case RTWS_SYNC:
1004                                 rcu_torture_writer_state = RTWS_SYNC;
1005                                 cur_ops->sync();
1006                                 rcu_torture_pipe_update(old_rp);
1007                                 break;
1008                         default:
1009                                 WARN_ON_ONCE(1);
1010                                 break;
1011                         }
1012                 }
1013                 rcutorture_record_progress(++rcu_torture_current_version);
1014                 /* Cycle through nesting levels of rcu_expedite_gp() calls. */
1015                 if (can_expedite &&
1016                     !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
1017                         WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
1018                         if (expediting >= 0)
1019                                 rcu_expedite_gp();
1020                         else
1021                                 rcu_unexpedite_gp();
1022                         if (++expediting > 3)
1023                                 expediting = -expediting;
1024                 } else if (!can_expedite) { /* Disabled during boot, recheck. */
1025                         can_expedite = !rcu_gp_is_expedited() &&
1026                                        !rcu_gp_is_normal();
1027                 }
1028                 rcu_torture_writer_state = RTWS_STUTTER;
1029                 stutter_wait("rcu_torture_writer");
1030         } while (!torture_must_stop());
1031         /* Reset expediting back to unexpedited. */
1032         if (expediting > 0)
1033                 expediting = -expediting;
1034         while (can_expedite && expediting++ < 0)
1035                 rcu_unexpedite_gp();
1036         WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
1037         if (!can_expedite)
1038                 pr_alert("%s" TORTURE_FLAG
1039                          " Dynamic grace-period expediting was disabled.\n",
1040                          torture_type);
1041         rcu_torture_writer_state = RTWS_STOPPING;
1042         torture_kthread_stopping("rcu_torture_writer");
1043         return 0;
1044 }
1045
1046 /*
1047  * RCU torture fake writer kthread.  Repeatedly calls sync, with a random
1048  * delay between calls.
1049  */
1050 static int
1051 rcu_torture_fakewriter(void *arg)
1052 {
1053         DEFINE_TORTURE_RANDOM(rand);
1054
1055         VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1056         set_user_nice(current, MAX_NICE);
1057
1058         do {
1059                 schedule_timeout_uninterruptible(1 + torture_random(&rand)%10);
1060                 udelay(torture_random(&rand) & 0x3ff);
1061                 if (cur_ops->cb_barrier != NULL &&
1062                     torture_random(&rand) % (nfakewriters * 8) == 0) {
1063                         cur_ops->cb_barrier();
1064                 } else if (gp_normal == gp_exp) {
1065                         if (cur_ops->sync && torture_random(&rand) & 0x80)
1066                                 cur_ops->sync();
1067                         else if (cur_ops->exp_sync)
1068                                 cur_ops->exp_sync();
1069                 } else if (gp_normal && cur_ops->sync) {
1070                         cur_ops->sync();
1071                 } else if (cur_ops->exp_sync) {
1072                         cur_ops->exp_sync();
1073                 }
1074                 stutter_wait("rcu_torture_fakewriter");
1075         } while (!torture_must_stop());
1076
1077         torture_kthread_stopping("rcu_torture_fakewriter");
1078         return 0;
1079 }
1080
1081 static void rcu_torture_timer_cb(struct rcu_head *rhp)
1082 {
1083         kfree(rhp);
1084 }
1085
1086 /*
1087  * RCU torture reader from timer handler.  Dereferences rcu_torture_current,
1088  * incrementing the corresponding element of the pipeline array.  The
1089  * counter in the element should never be greater than 1, otherwise, the
1090  * RCU implementation is broken.
1091  */
1092 static void rcu_torture_timer(struct timer_list *unused)
1093 {
1094         int idx;
1095         unsigned long started;
1096         unsigned long completed;
1097         static DEFINE_TORTURE_RANDOM(rand);
1098         static DEFINE_SPINLOCK(rand_lock);
1099         struct rcu_torture *p;
1100         int pipe_count;
1101         unsigned long long ts;
1102
1103         idx = cur_ops->readlock();
1104         if (cur_ops->started)
1105                 started = cur_ops->started();
1106         else
1107                 started = cur_ops->completed();
1108         ts = rcu_trace_clock_local();
1109         p = rcu_dereference_check(rcu_torture_current,
1110                                   rcu_read_lock_bh_held() ||
1111                                   rcu_read_lock_sched_held() ||
1112                                   srcu_read_lock_held(srcu_ctlp) ||
1113                                   torturing_tasks());
1114         if (p == NULL) {
1115                 /* Leave because rcu_torture_writer is not yet underway */
1116                 cur_ops->readunlock(idx);
1117                 return;
1118         }
1119         if (p->rtort_mbtest == 0)
1120                 atomic_inc(&n_rcu_torture_mberror);
1121         spin_lock(&rand_lock);
1122         cur_ops->read_delay(&rand);
1123         n_rcu_torture_timers++;
1124         spin_unlock(&rand_lock);
1125         preempt_disable();
1126         pipe_count = p->rtort_pipe_count;
1127         if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1128                 /* Should not happen, but... */
1129                 pipe_count = RCU_TORTURE_PIPE_LEN;
1130         }
1131         completed = cur_ops->completed();
1132         if (pipe_count > 1) {
1133                 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, ts,
1134                                           started, completed);
1135                 rcu_ftrace_dump(DUMP_ALL);
1136         }
1137         __this_cpu_inc(rcu_torture_count[pipe_count]);
1138         completed = completed - started;
1139         if (cur_ops->started)
1140                 completed++;
1141         if (completed > RCU_TORTURE_PIPE_LEN) {
1142                 /* Should not happen, but... */
1143                 completed = RCU_TORTURE_PIPE_LEN;
1144         }
1145         __this_cpu_inc(rcu_torture_batch[completed]);
1146         preempt_enable();
1147         cur_ops->readunlock(idx);
1148
1149         /* Test call_rcu() invocation from interrupt handler. */
1150         if (cur_ops->call) {
1151                 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT);
1152
1153                 if (rhp)
1154                         cur_ops->call(rhp, rcu_torture_timer_cb);
1155         }
1156 }
1157
1158 /*
1159  * RCU torture reader kthread.  Repeatedly dereferences rcu_torture_current,
1160  * incrementing the corresponding element of the pipeline array.  The
1161  * counter in the element should never be greater than 1, otherwise, the
1162  * RCU implementation is broken.
1163  */
1164 static int
1165 rcu_torture_reader(void *arg)
1166 {
1167         unsigned long started;
1168         unsigned long completed;
1169         int idx;
1170         DEFINE_TORTURE_RANDOM(rand);
1171         struct rcu_torture *p;
1172         int pipe_count;
1173         struct timer_list t;
1174         unsigned long long ts;
1175
1176         VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
1177         set_user_nice(current, MAX_NICE);
1178         if (irqreader && cur_ops->irq_capable)
1179                 timer_setup_on_stack(&t, rcu_torture_timer, 0);
1180
1181         do {
1182                 if (irqreader && cur_ops->irq_capable) {
1183                         if (!timer_pending(&t))
1184                                 mod_timer(&t, jiffies + 1);
1185                 }
1186                 idx = cur_ops->readlock();
1187                 if (cur_ops->started)
1188                         started = cur_ops->started();
1189                 else
1190                         started = cur_ops->completed();
1191                 ts = rcu_trace_clock_local();
1192                 p = rcu_dereference_check(rcu_torture_current,
1193                                           rcu_read_lock_bh_held() ||
1194                                           rcu_read_lock_sched_held() ||
1195                                           srcu_read_lock_held(srcu_ctlp) ||
1196                                           torturing_tasks());
1197                 if (p == NULL) {
1198                         /* Wait for rcu_torture_writer to get underway */
1199                         cur_ops->readunlock(idx);
1200                         schedule_timeout_interruptible(HZ);
1201                         continue;
1202                 }
1203                 if (p->rtort_mbtest == 0)
1204                         atomic_inc(&n_rcu_torture_mberror);
1205                 cur_ops->read_delay(&rand);
1206                 preempt_disable();
1207                 pipe_count = p->rtort_pipe_count;
1208                 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1209                         /* Should not happen, but... */
1210                         pipe_count = RCU_TORTURE_PIPE_LEN;
1211                 }
1212                 completed = cur_ops->completed();
1213                 if (pipe_count > 1) {
1214                         do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
1215                                                   ts, started, completed);
1216                         rcu_ftrace_dump(DUMP_ALL);
1217                 }
1218                 __this_cpu_inc(rcu_torture_count[pipe_count]);
1219                 completed = completed - started;
1220                 if (cur_ops->started)
1221                         completed++;
1222                 if (completed > RCU_TORTURE_PIPE_LEN) {
1223                         /* Should not happen, but... */
1224                         completed = RCU_TORTURE_PIPE_LEN;
1225                 }
1226                 __this_cpu_inc(rcu_torture_batch[completed]);
1227                 preempt_enable();
1228                 cur_ops->readunlock(idx);
1229                 stutter_wait("rcu_torture_reader");
1230         } while (!torture_must_stop());
1231         if (irqreader && cur_ops->irq_capable) {
1232                 del_timer_sync(&t);
1233                 destroy_timer_on_stack(&t);
1234         }
1235         torture_kthread_stopping("rcu_torture_reader");
1236         return 0;
1237 }
1238
1239 /*
1240  * Print torture statistics.  Caller must ensure that there is only
1241  * one call to this function at a given time!!!  This is normally
1242  * accomplished by relying on the module system to only have one copy
1243  * of the module loaded, and then by giving the rcu_torture_stats
1244  * kthread full control (or the init/cleanup functions when rcu_torture_stats
1245  * thread is not running).
1246  */
1247 static void
1248 rcu_torture_stats_print(void)
1249 {
1250         int cpu;
1251         int i;
1252         long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1253         long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1254         static unsigned long rtcv_snap = ULONG_MAX;
1255         static bool splatted;
1256         struct task_struct *wtp;
1257
1258         for_each_possible_cpu(cpu) {
1259                 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1260                         pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
1261                         batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
1262                 }
1263         }
1264         for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
1265                 if (pipesummary[i] != 0)
1266                         break;
1267         }
1268
1269         pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1270         pr_cont("rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
1271                 rcu_torture_current,
1272                 rcu_torture_current_version,
1273                 list_empty(&rcu_torture_freelist),
1274                 atomic_read(&n_rcu_torture_alloc),
1275                 atomic_read(&n_rcu_torture_alloc_fail),
1276                 atomic_read(&n_rcu_torture_free));
1277         pr_cont("rtmbe: %d rtbe: %ld rtbke: %ld rtbre: %ld ",
1278                 atomic_read(&n_rcu_torture_mberror),
1279                 n_rcu_torture_barrier_error,
1280                 n_rcu_torture_boost_ktrerror,
1281                 n_rcu_torture_boost_rterror);
1282         pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
1283                 n_rcu_torture_boost_failure,
1284                 n_rcu_torture_boosts,
1285                 n_rcu_torture_timers);
1286         torture_onoff_stats();
1287         pr_cont("barrier: %ld/%ld:%ld ",
1288                 n_barrier_successes,
1289                 n_barrier_attempts,
1290                 n_rcu_torture_barrier_error);
1291         pr_cont("cbflood: %ld\n", atomic_long_read(&n_cbfloods));
1292
1293         pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1294         if (atomic_read(&n_rcu_torture_mberror) != 0 ||
1295             n_rcu_torture_barrier_error != 0 ||
1296             n_rcu_torture_boost_ktrerror != 0 ||
1297             n_rcu_torture_boost_rterror != 0 ||
1298             n_rcu_torture_boost_failure != 0 ||
1299             i > 1) {
1300                 pr_cont("%s", "!!! ");
1301                 atomic_inc(&n_rcu_torture_error);
1302                 WARN_ON_ONCE(1);
1303         }
1304         pr_cont("Reader Pipe: ");
1305         for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1306                 pr_cont(" %ld", pipesummary[i]);
1307         pr_cont("\n");
1308
1309         pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1310         pr_cont("Reader Batch: ");
1311         for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1312                 pr_cont(" %ld", batchsummary[i]);
1313         pr_cont("\n");
1314
1315         pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1316         pr_cont("Free-Block Circulation: ");
1317         for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1318                 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
1319         }
1320         pr_cont("\n");
1321
1322         if (cur_ops->stats)
1323                 cur_ops->stats();
1324         if (rtcv_snap == rcu_torture_current_version &&
1325             rcu_torture_current != NULL) {
1326                 int __maybe_unused flags = 0;
1327                 unsigned long __maybe_unused gpnum = 0;
1328                 unsigned long __maybe_unused completed = 0;
1329
1330                 rcutorture_get_gp_data(cur_ops->ttype,
1331                                        &flags, &gpnum, &completed);
1332                 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp,
1333                                         &flags, &gpnum, &completed);
1334                 wtp = READ_ONCE(writer_task);
1335                 pr_alert("??? Writer stall state %s(%d) g%lu c%lu f%#x ->state %#lx cpu %d\n",
1336                          rcu_torture_writer_state_getname(),
1337                          rcu_torture_writer_state,
1338                          gpnum, completed, flags,
1339                          wtp == NULL ? ~0UL : wtp->state,
1340                          wtp == NULL ? -1 : (int)task_cpu(wtp));
1341                 if (!splatted && wtp) {
1342                         sched_show_task(wtp);
1343                         splatted = true;
1344                 }
1345                 show_rcu_gp_kthreads();
1346                 rcu_ftrace_dump(DUMP_ALL);
1347         }
1348         rtcv_snap = rcu_torture_current_version;
1349 }
1350
1351 /*
1352  * Periodically prints torture statistics, if periodic statistics printing
1353  * was specified via the stat_interval module parameter.
1354  */
1355 static int
1356 rcu_torture_stats(void *arg)
1357 {
1358         VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1359         do {
1360                 schedule_timeout_interruptible(stat_interval * HZ);
1361                 rcu_torture_stats_print();
1362                 torture_shutdown_absorb("rcu_torture_stats");
1363         } while (!torture_must_stop());
1364         torture_kthread_stopping("rcu_torture_stats");
1365         return 0;
1366 }
1367
1368 static inline void
1369 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1370 {
1371         pr_alert("%s" TORTURE_FLAG
1372                  "--- %s: nreaders=%d nfakewriters=%d "
1373                  "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1374                  "shuffle_interval=%d stutter=%d irqreader=%d "
1375                  "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1376                  "test_boost=%d/%d test_boost_interval=%d "
1377                  "test_boost_duration=%d shutdown_secs=%d "
1378                  "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d "
1379                  "n_barrier_cbs=%d "
1380                  "onoff_interval=%d onoff_holdoff=%d\n",
1381                  torture_type, tag, nrealreaders, nfakewriters,
1382                  stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1383                  stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1384                  test_boost, cur_ops->can_boost,
1385                  test_boost_interval, test_boost_duration, shutdown_secs,
1386                  stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff,
1387                  n_barrier_cbs,
1388                  onoff_interval, onoff_holdoff);
1389 }
1390
1391 static int rcutorture_booster_cleanup(unsigned int cpu)
1392 {
1393         struct task_struct *t;
1394
1395         if (boost_tasks[cpu] == NULL)
1396                 return 0;
1397         mutex_lock(&boost_mutex);
1398         t = boost_tasks[cpu];
1399         boost_tasks[cpu] = NULL;
1400         mutex_unlock(&boost_mutex);
1401
1402         /* This must be outside of the mutex, otherwise deadlock! */
1403         torture_stop_kthread(rcu_torture_boost, t);
1404         return 0;
1405 }
1406
1407 static int rcutorture_booster_init(unsigned int cpu)
1408 {
1409         int retval;
1410
1411         if (boost_tasks[cpu] != NULL)
1412                 return 0;  /* Already created, nothing more to do. */
1413
1414         /* Don't allow time recalculation while creating a new task. */
1415         mutex_lock(&boost_mutex);
1416         VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
1417         boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
1418                                                   cpu_to_node(cpu),
1419                                                   "rcu_torture_boost");
1420         if (IS_ERR(boost_tasks[cpu])) {
1421                 retval = PTR_ERR(boost_tasks[cpu]);
1422                 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
1423                 n_rcu_torture_boost_ktrerror++;
1424                 boost_tasks[cpu] = NULL;
1425                 mutex_unlock(&boost_mutex);
1426                 return retval;
1427         }
1428         kthread_bind(boost_tasks[cpu], cpu);
1429         wake_up_process(boost_tasks[cpu]);
1430         mutex_unlock(&boost_mutex);
1431         return 0;
1432 }
1433
1434 /*
1435  * CPU-stall kthread.  It waits as specified by stall_cpu_holdoff, then
1436  * induces a CPU stall for the time specified by stall_cpu.
1437  */
1438 static int rcu_torture_stall(void *args)
1439 {
1440         unsigned long stop_at;
1441
1442         VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
1443         if (stall_cpu_holdoff > 0) {
1444                 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
1445                 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
1446                 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
1447         }
1448         if (!kthread_should_stop()) {
1449                 stop_at = get_seconds() + stall_cpu;
1450                 /* RCU CPU stall is expected behavior in following code. */
1451                 rcu_read_lock();
1452                 if (stall_cpu_irqsoff)
1453                         local_irq_disable();
1454                 else
1455                         preempt_disable();
1456                 pr_alert("rcu_torture_stall start on CPU %d.\n",
1457                          smp_processor_id());
1458                 while (ULONG_CMP_LT(get_seconds(), stop_at))
1459                         continue;  /* Induce RCU CPU stall warning. */
1460                 if (stall_cpu_irqsoff)
1461                         local_irq_enable();
1462                 else
1463                         preempt_enable();
1464                 rcu_read_unlock();
1465                 pr_alert("rcu_torture_stall end.\n");
1466         }
1467         torture_shutdown_absorb("rcu_torture_stall");
1468         while (!kthread_should_stop())
1469                 schedule_timeout_interruptible(10 * HZ);
1470         return 0;
1471 }
1472
1473 /* Spawn CPU-stall kthread, if stall_cpu specified. */
1474 static int __init rcu_torture_stall_init(void)
1475 {
1476         if (stall_cpu <= 0)
1477                 return 0;
1478         return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
1479 }
1480
1481 /* Callback function for RCU barrier testing. */
1482 static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
1483 {
1484         atomic_inc(&barrier_cbs_invoked);
1485 }
1486
1487 /* kthread function to register callbacks used to test RCU barriers. */
1488 static int rcu_torture_barrier_cbs(void *arg)
1489 {
1490         long myid = (long)arg;
1491         bool lastphase = 0;
1492         bool newphase;
1493         struct rcu_head rcu;
1494
1495         init_rcu_head_on_stack(&rcu);
1496         VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
1497         set_user_nice(current, MAX_NICE);
1498         do {
1499                 wait_event(barrier_cbs_wq[myid],
1500                            (newphase =
1501                             smp_load_acquire(&barrier_phase)) != lastphase ||
1502                            torture_must_stop());
1503                 lastphase = newphase;
1504                 if (torture_must_stop())
1505                         break;
1506                 /*
1507                  * The above smp_load_acquire() ensures barrier_phase load
1508                  * is ordered before the following ->call().
1509                  */
1510                 local_irq_disable(); /* Just to test no-irq call_rcu(). */
1511                 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
1512                 local_irq_enable();
1513                 if (atomic_dec_and_test(&barrier_cbs_count))
1514                         wake_up(&barrier_wq);
1515         } while (!torture_must_stop());
1516         if (cur_ops->cb_barrier != NULL)
1517                 cur_ops->cb_barrier();
1518         destroy_rcu_head_on_stack(&rcu);
1519         torture_kthread_stopping("rcu_torture_barrier_cbs");
1520         return 0;
1521 }
1522
1523 /* kthread function to drive and coordinate RCU barrier testing. */
1524 static int rcu_torture_barrier(void *arg)
1525 {
1526         int i;
1527
1528         VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
1529         do {
1530                 atomic_set(&barrier_cbs_invoked, 0);
1531                 atomic_set(&barrier_cbs_count, n_barrier_cbs);
1532                 /* Ensure barrier_phase ordered after prior assignments. */
1533                 smp_store_release(&barrier_phase, !barrier_phase);
1534                 for (i = 0; i < n_barrier_cbs; i++)
1535                         wake_up(&barrier_cbs_wq[i]);
1536                 wait_event(barrier_wq,
1537                            atomic_read(&barrier_cbs_count) == 0 ||
1538                            torture_must_stop());
1539                 if (torture_must_stop())
1540                         break;
1541                 n_barrier_attempts++;
1542                 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
1543                 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
1544                         n_rcu_torture_barrier_error++;
1545                         pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
1546                                atomic_read(&barrier_cbs_invoked),
1547                                n_barrier_cbs);
1548                         WARN_ON_ONCE(1);
1549                 }
1550                 n_barrier_successes++;
1551                 schedule_timeout_interruptible(HZ / 10);
1552         } while (!torture_must_stop());
1553         torture_kthread_stopping("rcu_torture_barrier");
1554         return 0;
1555 }
1556
1557 /* Initialize RCU barrier testing. */
1558 static int rcu_torture_barrier_init(void)
1559 {
1560         int i;
1561         int ret;
1562
1563         if (n_barrier_cbs <= 0)
1564                 return 0;
1565         if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
1566                 pr_alert("%s" TORTURE_FLAG
1567                          " Call or barrier ops missing for %s,\n",
1568                          torture_type, cur_ops->name);
1569                 pr_alert("%s" TORTURE_FLAG
1570                          " RCU barrier testing omitted from run.\n",
1571                          torture_type);
1572                 return 0;
1573         }
1574         atomic_set(&barrier_cbs_count, 0);
1575         atomic_set(&barrier_cbs_invoked, 0);
1576         barrier_cbs_tasks =
1577                 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]),
1578                         GFP_KERNEL);
1579         barrier_cbs_wq =
1580                 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL);
1581         if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
1582                 return -ENOMEM;
1583         for (i = 0; i < n_barrier_cbs; i++) {
1584                 init_waitqueue_head(&barrier_cbs_wq[i]);
1585                 ret = torture_create_kthread(rcu_torture_barrier_cbs,
1586                                              (void *)(long)i,
1587                                              barrier_cbs_tasks[i]);
1588                 if (ret)
1589                         return ret;
1590         }
1591         return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
1592 }
1593
1594 /* Clean up after RCU barrier testing. */
1595 static void rcu_torture_barrier_cleanup(void)
1596 {
1597         int i;
1598
1599         torture_stop_kthread(rcu_torture_barrier, barrier_task);
1600         if (barrier_cbs_tasks != NULL) {
1601                 for (i = 0; i < n_barrier_cbs; i++)
1602                         torture_stop_kthread(rcu_torture_barrier_cbs,
1603                                              barrier_cbs_tasks[i]);
1604                 kfree(barrier_cbs_tasks);
1605                 barrier_cbs_tasks = NULL;
1606         }
1607         if (barrier_cbs_wq != NULL) {
1608                 kfree(barrier_cbs_wq);
1609                 barrier_cbs_wq = NULL;
1610         }
1611 }
1612
1613 static enum cpuhp_state rcutor_hp;
1614
1615 static void
1616 rcu_torture_cleanup(void)
1617 {
1618         int flags = 0;
1619         unsigned long gpnum = 0;
1620         unsigned long completed = 0;
1621         int i;
1622
1623         rcutorture_record_test_transition();
1624         if (torture_cleanup_begin()) {
1625                 if (cur_ops->cb_barrier != NULL)
1626                         cur_ops->cb_barrier();
1627                 return;
1628         }
1629
1630         rcu_torture_barrier_cleanup();
1631         torture_stop_kthread(rcu_torture_stall, stall_task);
1632         torture_stop_kthread(rcu_torture_writer, writer_task);
1633
1634         if (reader_tasks) {
1635                 for (i = 0; i < nrealreaders; i++)
1636                         torture_stop_kthread(rcu_torture_reader,
1637                                              reader_tasks[i]);
1638                 kfree(reader_tasks);
1639         }
1640         rcu_torture_current = NULL;
1641
1642         if (fakewriter_tasks) {
1643                 for (i = 0; i < nfakewriters; i++) {
1644                         torture_stop_kthread(rcu_torture_fakewriter,
1645                                              fakewriter_tasks[i]);
1646                 }
1647                 kfree(fakewriter_tasks);
1648                 fakewriter_tasks = NULL;
1649         }
1650
1651         rcutorture_get_gp_data(cur_ops->ttype, &flags, &gpnum, &completed);
1652         srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp,
1653                                 &flags, &gpnum, &completed);
1654         pr_alert("%s:  End-test grace-period state: g%lu c%lu f%#x\n",
1655                  cur_ops->name, gpnum, completed, flags);
1656         torture_stop_kthread(rcu_torture_stats, stats_task);
1657         torture_stop_kthread(rcu_torture_fqs, fqs_task);
1658         for (i = 0; i < ncbflooders; i++)
1659                 torture_stop_kthread(rcu_torture_cbflood, cbflood_task[i]);
1660         if ((test_boost == 1 && cur_ops->can_boost) ||
1661             test_boost == 2)
1662                 cpuhp_remove_state(rcutor_hp);
1663
1664         /*
1665          * Wait for all RCU callbacks to fire, then do flavor-specific
1666          * cleanup operations.
1667          */
1668         if (cur_ops->cb_barrier != NULL)
1669                 cur_ops->cb_barrier();
1670         if (cur_ops->cleanup != NULL)
1671                 cur_ops->cleanup();
1672
1673         rcu_torture_stats_print();  /* -After- the stats thread is stopped! */
1674
1675         if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
1676                 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
1677         else if (torture_onoff_failures())
1678                 rcu_torture_print_module_parms(cur_ops,
1679                                                "End of test: RCU_HOTPLUG");
1680         else
1681                 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
1682         torture_cleanup_end();
1683 }
1684
1685 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1686 static void rcu_torture_leak_cb(struct rcu_head *rhp)
1687 {
1688 }
1689
1690 static void rcu_torture_err_cb(struct rcu_head *rhp)
1691 {
1692         /*
1693          * This -might- happen due to race conditions, but is unlikely.
1694          * The scenario that leads to this happening is that the
1695          * first of the pair of duplicate callbacks is queued,
1696          * someone else starts a grace period that includes that
1697          * callback, then the second of the pair must wait for the
1698          * next grace period.  Unlikely, but can happen.  If it
1699          * does happen, the debug-objects subsystem won't have splatted.
1700          */
1701         pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME);
1702 }
1703 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1704
1705 /*
1706  * Verify that double-free causes debug-objects to complain, but only
1707  * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y.  Otherwise, say that the test
1708  * cannot be carried out.
1709  */
1710 static void rcu_test_debug_objects(void)
1711 {
1712 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1713         struct rcu_head rh1;
1714         struct rcu_head rh2;
1715
1716         init_rcu_head_on_stack(&rh1);
1717         init_rcu_head_on_stack(&rh2);
1718         pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME);
1719
1720         /* Try to queue the rh2 pair of callbacks for the same grace period. */
1721         preempt_disable(); /* Prevent preemption from interrupting test. */
1722         rcu_read_lock(); /* Make it impossible to finish a grace period. */
1723         call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
1724         local_irq_disable(); /* Make it harder to start a new grace period. */
1725         call_rcu(&rh2, rcu_torture_leak_cb);
1726         call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
1727         local_irq_enable();
1728         rcu_read_unlock();
1729         preempt_enable();
1730
1731         /* Wait for them all to get done so we can safely return. */
1732         rcu_barrier();
1733         pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME);
1734         destroy_rcu_head_on_stack(&rh1);
1735         destroy_rcu_head_on_stack(&rh2);
1736 #else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1737         pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME);
1738 #endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1739 }
1740
1741 static int __init
1742 rcu_torture_init(void)
1743 {
1744         int i;
1745         int cpu;
1746         int firsterr = 0;
1747         static struct rcu_torture_ops *torture_ops[] = {
1748                 &rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops,
1749                 &sched_ops, &tasks_ops,
1750         };
1751
1752         if (!torture_init_begin(torture_type, verbose))
1753                 return -EBUSY;
1754
1755         /* Process args and tell the world that the torturer is on the job. */
1756         for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1757                 cur_ops = torture_ops[i];
1758                 if (strcmp(torture_type, cur_ops->name) == 0)
1759                         break;
1760         }
1761         if (i == ARRAY_SIZE(torture_ops)) {
1762                 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
1763                          torture_type);
1764                 pr_alert("rcu-torture types:");
1765                 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1766                         pr_alert(" %s", torture_ops[i]->name);
1767                 pr_alert("\n");
1768                 firsterr = -EINVAL;
1769                 goto unwind;
1770         }
1771         if (cur_ops->fqs == NULL && fqs_duration != 0) {
1772                 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
1773                 fqs_duration = 0;
1774         }
1775         if (cur_ops->init)
1776                 cur_ops->init();
1777
1778         if (nreaders >= 0) {
1779                 nrealreaders = nreaders;
1780         } else {
1781                 nrealreaders = num_online_cpus() - 2 - nreaders;
1782                 if (nrealreaders <= 0)
1783                         nrealreaders = 1;
1784         }
1785         rcu_torture_print_module_parms(cur_ops, "Start of test");
1786
1787         /* Set up the freelist. */
1788
1789         INIT_LIST_HEAD(&rcu_torture_freelist);
1790         for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1791                 rcu_tortures[i].rtort_mbtest = 0;
1792                 list_add_tail(&rcu_tortures[i].rtort_free,
1793                               &rcu_torture_freelist);
1794         }
1795
1796         /* Initialize the statistics so that each run gets its own numbers. */
1797
1798         rcu_torture_current = NULL;
1799         rcu_torture_current_version = 0;
1800         atomic_set(&n_rcu_torture_alloc, 0);
1801         atomic_set(&n_rcu_torture_alloc_fail, 0);
1802         atomic_set(&n_rcu_torture_free, 0);
1803         atomic_set(&n_rcu_torture_mberror, 0);
1804         atomic_set(&n_rcu_torture_error, 0);
1805         n_rcu_torture_barrier_error = 0;
1806         n_rcu_torture_boost_ktrerror = 0;
1807         n_rcu_torture_boost_rterror = 0;
1808         n_rcu_torture_boost_failure = 0;
1809         n_rcu_torture_boosts = 0;
1810         for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1811                 atomic_set(&rcu_torture_wcount[i], 0);
1812         for_each_possible_cpu(cpu) {
1813                 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1814                         per_cpu(rcu_torture_count, cpu)[i] = 0;
1815                         per_cpu(rcu_torture_batch, cpu)[i] = 0;
1816                 }
1817         }
1818
1819         /* Start up the kthreads. */
1820
1821         firsterr = torture_create_kthread(rcu_torture_writer, NULL,
1822                                           writer_task);
1823         if (firsterr)
1824                 goto unwind;
1825         if (nfakewriters > 0) {
1826                 fakewriter_tasks = kcalloc(nfakewriters,
1827                                            sizeof(fakewriter_tasks[0]),
1828                                            GFP_KERNEL);
1829                 if (fakewriter_tasks == NULL) {
1830                         VERBOSE_TOROUT_ERRSTRING("out of memory");
1831                         firsterr = -ENOMEM;
1832                         goto unwind;
1833                 }
1834         }
1835         for (i = 0; i < nfakewriters; i++) {
1836                 firsterr = torture_create_kthread(rcu_torture_fakewriter,
1837                                                   NULL, fakewriter_tasks[i]);
1838                 if (firsterr)
1839                         goto unwind;
1840         }
1841         reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
1842                                GFP_KERNEL);
1843         if (reader_tasks == NULL) {
1844                 VERBOSE_TOROUT_ERRSTRING("out of memory");
1845                 firsterr = -ENOMEM;
1846                 goto unwind;
1847         }
1848         for (i = 0; i < nrealreaders; i++) {
1849                 firsterr = torture_create_kthread(rcu_torture_reader, NULL,
1850                                                   reader_tasks[i]);
1851                 if (firsterr)
1852                         goto unwind;
1853         }
1854         if (stat_interval > 0) {
1855                 firsterr = torture_create_kthread(rcu_torture_stats, NULL,
1856                                                   stats_task);
1857                 if (firsterr)
1858                         goto unwind;
1859         }
1860         if (test_no_idle_hz && shuffle_interval > 0) {
1861                 firsterr = torture_shuffle_init(shuffle_interval * HZ);
1862                 if (firsterr)
1863                         goto unwind;
1864         }
1865         if (stutter < 0)
1866                 stutter = 0;
1867         if (stutter) {
1868                 firsterr = torture_stutter_init(stutter * HZ);
1869                 if (firsterr)
1870                         goto unwind;
1871         }
1872         if (fqs_duration < 0)
1873                 fqs_duration = 0;
1874         if (fqs_duration) {
1875                 /* Create the fqs thread */
1876                 firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
1877                                                   fqs_task);
1878                 if (firsterr)
1879                         goto unwind;
1880         }
1881         if (test_boost_interval < 1)
1882                 test_boost_interval = 1;
1883         if (test_boost_duration < 2)
1884                 test_boost_duration = 2;
1885         if ((test_boost == 1 && cur_ops->can_boost) ||
1886             test_boost == 2) {
1887
1888                 boost_starttime = jiffies + test_boost_interval * HZ;
1889
1890                 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE",
1891                                              rcutorture_booster_init,
1892                                              rcutorture_booster_cleanup);
1893                 if (firsterr < 0)
1894                         goto unwind;
1895                 rcutor_hp = firsterr;
1896         }
1897         firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
1898         if (firsterr)
1899                 goto unwind;
1900         firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval * HZ);
1901         if (firsterr)
1902                 goto unwind;
1903         firsterr = rcu_torture_stall_init();
1904         if (firsterr)
1905                 goto unwind;
1906         firsterr = rcu_torture_barrier_init();
1907         if (firsterr)
1908                 goto unwind;
1909         if (object_debug)
1910                 rcu_test_debug_objects();
1911         if (cbflood_n_burst > 0) {
1912                 /* Create the cbflood threads */
1913                 ncbflooders = (num_online_cpus() + 3) / 4;
1914                 cbflood_task = kcalloc(ncbflooders, sizeof(*cbflood_task),
1915                                        GFP_KERNEL);
1916                 if (!cbflood_task) {
1917                         VERBOSE_TOROUT_ERRSTRING("out of memory");
1918                         firsterr = -ENOMEM;
1919                         goto unwind;
1920                 }
1921                 for (i = 0; i < ncbflooders; i++) {
1922                         firsterr = torture_create_kthread(rcu_torture_cbflood,
1923                                                           NULL,
1924                                                           cbflood_task[i]);
1925                         if (firsterr)
1926                                 goto unwind;
1927                 }
1928         }
1929         rcutorture_record_test_transition();
1930         torture_init_end();
1931         return 0;
1932
1933 unwind:
1934         torture_init_end();
1935         rcu_torture_cleanup();
1936         return firsterr;
1937 }
1938
1939 module_init(rcu_torture_init);
1940 module_exit(rcu_torture_cleanup);