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
  55 MODULE_LICENSE("GPL");
  56 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
  57
  58
  59 torture_param(int, cbflood_inter_holdoff, HZ,
  60               "Holdoff between floods (jiffies)");
  61 torture_param(int, cbflood_intra_holdoff, 1,
  62               "Holdoff between bursts (jiffies)");
  63 torture_param(int, cbflood_n_burst, 3, "# bursts in flood, zero to disable");
  64 torture_param(int, cbflood_n_per_burst, 20000,
  65               "# callbacks per burst in flood");
  66 torture_param(int, fqs_duration, 0,
  67               "Duration of fqs bursts (us), 0 to disable");
  68 torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
  69 torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
  70 torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
  71 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
  72 torture_param(bool, gp_normal, false,
  73              "Use normal (non-expedited) GP wait primitives");
  74 torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
  75 torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
  76 torture_param(int, n_barrier_cbs, 0,
  77              "# of callbacks/kthreads for barrier testing");
  78 torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
  79 torture_param(int, nreaders, -1, "Number of RCU reader threads");
  80 torture_param(int, object_debug, 0,
  81              "Enable debug-object double call_rcu() testing");
  82 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
  83 torture_param(int, onoff_interval, 0,
  84              "Time between CPU hotplugs (s), 0=disable");
  85 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
  86 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
  87 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
  88 torture_param(int, stall_cpu_holdoff, 10,
  89              "Time to wait before starting stall (s).");
  90 torture_param(int, stat_interval, 60,
  91              "Number of seconds between stats printk()s");
  92 torture_param(int, stutter, 5, "Number of seconds to run/halt test");
  93 torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
  94 torture_param(int, test_boost_duration, 4,
  95              "Duration of each boost test, seconds.");
  96 torture_param(int, test_boost_interval, 7,
  97              "Interval between boost tests, seconds.");
  98 torture_param(bool, test_no_idle_hz, true,
  99              "Test support for tickless idle CPUs");
 100 torture_param(bool, verbose, true,
 101              "Enable verbose debugging printk()s");
 102
 103 static char *torture_type = "rcu";
 104 module_param(torture_type, charp, 0444);
 105 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, ...)");
 106
 107 static int nrealreaders;
 108 static int ncbflooders;
 109 static struct task_struct *writer_task;
 110 static struct task_struct **fakewriter_tasks;
 111 static struct task_struct **reader_tasks;
 112 static struct task_struct *stats_task;
 113 static struct task_struct **cbflood_task;
 114 static struct task_struct *fqs_task;
 115 static struct task_struct *boost_tasks[NR_CPUS];
 116 static struct task_struct *stall_task;
 117 static struct task_struct **barrier_cbs_tasks;
 118 static struct task_struct *barrier_task;
 119
 120 #define RCU_TORTURE_PIPE_LEN 10
 121
 122 struct rcu_torture {
 123         struct rcu_head rtort_rcu;
 124         int rtort_pipe_count;
 125         struct list_head rtort_free;
 126         int rtort_mbtest;
 127 };
 128
 129 static LIST_HEAD(rcu_torture_freelist);
 130 static struct rcu_torture __rcu *rcu_torture_current;
 131 static unsigned long rcu_torture_current_version;
 132 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
 133 static DEFINE_SPINLOCK(rcu_torture_lock);
 134 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count);
 135 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch);
 136 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
 137 static atomic_t n_rcu_torture_alloc;
 138 static atomic_t n_rcu_torture_alloc_fail;
 139 static atomic_t n_rcu_torture_free;
 140 static atomic_t n_rcu_torture_mberror;
 141 static atomic_t n_rcu_torture_error;
 142 static long n_rcu_torture_barrier_error;
 143 static long n_rcu_torture_boost_ktrerror;
 144 static long n_rcu_torture_boost_rterror;
 145 static long n_rcu_torture_boost_failure;
 146 static long n_rcu_torture_boosts;
 147 static long n_rcu_torture_timers;
 148 static long n_barrier_attempts;
 149 static long n_barrier_successes;
 150 static atomic_long_t n_cbfloods;
 151 static struct list_head rcu_torture_removed;
 152
 153 static int rcu_torture_writer_state;
 154 #define RTWS_FIXED_DELAY        0
 155 #define RTWS_DELAY              1
 156 #define RTWS_REPLACE            2
 157 #define RTWS_DEF_FREE           3
 158 #define RTWS_EXP_SYNC           4
 159 #define RTWS_COND_GET           5
 160 #define RTWS_COND_SYNC          6
 161 #define RTWS_SYNC               7
 162 #define RTWS_STUTTER            8
 163 #define RTWS_STOPPING           9
 164 static const char * const rcu_torture_writer_state_names[] = {
 165         "RTWS_FIXED_DELAY",
 166         "RTWS_DELAY",
 167         "RTWS_REPLACE",
 168         "RTWS_DEF_FREE",
 169         "RTWS_EXP_SYNC",
 170         "RTWS_COND_GET",
 171         "RTWS_COND_SYNC",
 172         "RTWS_SYNC",
 173         "RTWS_STUTTER",
 174         "RTWS_STOPPING",
 175 };
 176
 177 static const char *rcu_torture_writer_state_getname(void)
 178 {
 179         unsigned int i = READ_ONCE(rcu_torture_writer_state);
 180
 181         if (i >= ARRAY_SIZE(rcu_torture_writer_state_names))
 182                 return "???";
 183         return rcu_torture_writer_state_names[i];
 184 }
 185
 186 static int torture_runnable = IS_ENABLED(MODULE);
 187 module_param(torture_runnable, int, 0444);
 188 MODULE_PARM_DESC(torture_runnable, "Start rcutorture at boot");
 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         unsigned long __maybe_unused ts_rem = do_div(ts, NSEC_PER_USEC);
 201         return ts;
 202 }
 203 #else /* #ifdef CONFIG_RCU_TRACE */
 204 static u64 notrace rcu_trace_clock_local(void)
 205 {
 206         return 0ULL;
 207 }
 208 #endif /* #else #ifdef CONFIG_RCU_TRACE */
 209
 210 static unsigned long boost_starttime;   /* jiffies of next boost test start. */
 211 static DEFINE_MUTEX(boost_mutex);       /* protect setting boost_starttime */
 212                                         /*  and boost task create/destroy. */
 213 static atomic_t barrier_cbs_count;      /* Barrier callbacks registered. */
 214 static bool barrier_phase;              /* Test phase. */
 215 static atomic_t barrier_cbs_invoked;    /* Barrier callbacks invoked. */
 216 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
 217 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
 218
 219 /*
 220  * Allocate an element from the rcu_tortures pool.
 221  */
 222 static struct rcu_torture *
 223 rcu_torture_alloc(void)
 224 {
 225         struct list_head *p;
 226
 227         spin_lock_bh(&rcu_torture_lock);
 228         if (list_empty(&rcu_torture_freelist)) {
 229                 atomic_inc(&n_rcu_torture_alloc_fail);
 230                 spin_unlock_bh(&rcu_torture_lock);
 231                 return NULL;
 232         }
 233         atomic_inc(&n_rcu_torture_alloc);
 234         p = rcu_torture_freelist.next;
 235         list_del_init(p);
 236         spin_unlock_bh(&rcu_torture_lock);
 237         return container_of(p, struct rcu_torture, rtort_free);
 238 }
 239
 240 /*
 241  * Free an element to the rcu_tortures pool.
 242  */
 243 static void
 244 rcu_torture_free(struct rcu_torture *p)
 245 {
 246         atomic_inc(&n_rcu_torture_free);
 247         spin_lock_bh(&rcu_torture_lock);
 248         list_add_tail(&p->rtort_free, &rcu_torture_freelist);
 249         spin_unlock_bh(&rcu_torture_lock);
 250 }
 251
 252 /*
 253  * Operations vector for selecting different types of tests.
 254  */
 255
 256 struct rcu_torture_ops {
 257         int ttype;
 258         void (*init)(void);
 259         void (*cleanup)(void);
 260         int (*readlock)(void);
 261         void (*read_delay)(struct torture_random_state *rrsp);
 262         void (*readunlock)(int idx);
 263         unsigned long (*started)(void);
 264         unsigned long (*completed)(void);
 265         void (*deferred_free)(struct rcu_torture *p);
 266         void (*sync)(void);
 267         void (*exp_sync)(void);
 268         unsigned long (*get_state)(void);
 269         void (*cond_sync)(unsigned long oldstate);
 270         call_rcu_func_t call;
 271         void (*cb_barrier)(void);
 272         void (*fqs)(void);
 273         void (*stats)(void);
 274         int irq_capable;
 275         int can_boost;
 276         const char *name;
 277 };
 278
 279 static struct rcu_torture_ops *cur_ops;
 280
 281 /*
 282  * Definitions for rcu torture testing.
 283  */
 284
 285 static int rcu_torture_read_lock(void) __acquires(RCU)
 286 {
 287         rcu_read_lock();
 288         return 0;
 289 }
 290
 291 static void rcu_read_delay(struct torture_random_state *rrsp)
 292 {
 293         unsigned long started;
 294         unsigned long completed;
 295         const unsigned long shortdelay_us = 200;
 296         const unsigned long longdelay_ms = 50;
 297         unsigned long long ts;
 298
 299         /* We want a short delay sometimes to make a reader delay the grace
 300          * period, and we want a long delay occasionally to trigger
 301          * force_quiescent_state. */
 302
 303         if (!(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) {
 304                 started = cur_ops->completed();
 305                 ts = rcu_trace_clock_local();
 306                 mdelay(longdelay_ms);
 307                 completed = cur_ops->completed();
 308                 do_trace_rcu_torture_read(cur_ops->name, NULL, ts,
 309                                           started, completed);
 310         }
 311         if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
 312                 udelay(shortdelay_us);
 313 #ifdef CONFIG_PREEMPT
 314         if (!preempt_count() &&
 315             !(torture_random(rrsp) % (nrealreaders * 20000)))
 316                 preempt_schedule();  /* No QS if preempt_disable() in effect */
 317 #endif
 318 }
 319
 320 static void rcu_torture_read_unlock(int idx) __releases(RCU)
 321 {
 322         rcu_read_unlock();
 323 }
 324
 325 /*
 326  * Update callback in the pipe.  This should be invoked after a grace period.
 327  */
 328 static bool
 329 rcu_torture_pipe_update_one(struct rcu_torture *rp)
 330 {
 331         int i;
 332
 333         i = rp->rtort_pipe_count;
 334         if (i > RCU_TORTURE_PIPE_LEN)
 335                 i = RCU_TORTURE_PIPE_LEN;
 336         atomic_inc(&rcu_torture_wcount[i]);
 337         if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
 338                 rp->rtort_mbtest = 0;
 339                 return true;
 340         }
 341         return false;
 342 }
 343
 344 /*
 345  * Update all callbacks in the pipe.  Suitable for synchronous grace-period
 346  * primitives.
 347  */
 348 static void
 349 rcu_torture_pipe_update(struct rcu_torture *old_rp)
 350 {
 351         struct rcu_torture *rp;
 352         struct rcu_torture *rp1;
 353
 354         if (old_rp)
 355                 list_add(&old_rp->rtort_free, &rcu_torture_removed);
 356         list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
 357                 if (rcu_torture_pipe_update_one(rp)) {
 358                         list_del(&rp->rtort_free);
 359                         rcu_torture_free(rp);
 360                 }
 361         }
 362 }
 363
 364 static void
 365 rcu_torture_cb(struct rcu_head *p)
 366 {
 367         struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
 368
 369         if (torture_must_stop_irq()) {
 370                 /* Test is ending, just drop callbacks on the floor. */
 371                 /* The next initialization will pick up the pieces. */
 372                 return;
 373         }
 374         if (rcu_torture_pipe_update_one(rp))
 375                 rcu_torture_free(rp);
 376         else
 377                 cur_ops->deferred_free(rp);
 378 }
 379
 380 static unsigned long rcu_no_completed(void)
 381 {
 382         return 0;
 383 }
 384
 385 static void rcu_torture_deferred_free(struct rcu_torture *p)
 386 {
 387         call_rcu(&p->rtort_rcu, rcu_torture_cb);
 388 }
 389
 390 static void rcu_sync_torture_init(void)
 391 {
 392         INIT_LIST_HEAD(&rcu_torture_removed);
 393 }
 394
 395 static struct rcu_torture_ops rcu_ops = {
 396         .ttype          = RCU_FLAVOR,
 397         .init           = rcu_sync_torture_init,
 398         .readlock       = rcu_torture_read_lock,
 399         .read_delay     = rcu_read_delay,
 400         .readunlock     = rcu_torture_read_unlock,
 401         .started        = rcu_batches_started,
 402         .completed      = rcu_batches_completed,
 403         .deferred_free  = rcu_torture_deferred_free,
 404         .sync           = synchronize_rcu,
 405         .exp_sync       = synchronize_rcu_expedited,
 406         .get_state      = get_state_synchronize_rcu,
 407         .cond_sync      = cond_synchronize_rcu,
 408         .call           = call_rcu,
 409         .cb_barrier     = rcu_barrier,
 410         .fqs            = rcu_force_quiescent_state,
 411         .stats          = NULL,
 412         .irq_capable    = 1,
 413         .can_boost      = rcu_can_boost(),
 414         .name           = "rcu"
 415 };
 416
 417 /*
 418  * Definitions for rcu_bh torture testing.
 419  */
 420
 421 static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
 422 {
 423         rcu_read_lock_bh();
 424         return 0;
 425 }
 426
 427 static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
 428 {
 429         rcu_read_unlock_bh();
 430 }
 431
 432 static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
 433 {
 434         call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
 435 }
 436
 437 static struct rcu_torture_ops rcu_bh_ops = {
 438         .ttype          = RCU_BH_FLAVOR,
 439         .init           = rcu_sync_torture_init,
 440         .readlock       = rcu_bh_torture_read_lock,
 441         .read_delay     = rcu_read_delay,  /* just reuse rcu's version. */
 442         .readunlock     = rcu_bh_torture_read_unlock,
 443         .started        = rcu_batches_started_bh,
 444         .completed      = rcu_batches_completed_bh,
 445         .deferred_free  = rcu_bh_torture_deferred_free,
 446         .sync           = synchronize_rcu_bh,
 447         .exp_sync       = synchronize_rcu_bh_expedited,
 448         .call           = call_rcu_bh,
 449         .cb_barrier     = rcu_barrier_bh,
 450         .fqs            = rcu_bh_force_quiescent_state,
 451         .stats          = NULL,
 452         .irq_capable    = 1,
 453         .name           = "rcu_bh"
 454 };
 455
 456 /*
 457  * Don't even think about trying any of these in real life!!!
 458  * The names includes "busted", and they really means it!
 459  * The only purpose of these functions is to provide a buggy RCU
 460  * implementation to make sure that rcutorture correctly emits
 461  * buggy-RCU error messages.
 462  */
 463 static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
 464 {
 465         /* This is a deliberate bug for testing purposes only! */
 466         rcu_torture_cb(&p->rtort_rcu);
 467 }
 468
 469 static void synchronize_rcu_busted(void)
 470 {
 471         /* This is a deliberate bug for testing purposes only! */
 472 }
 473
 474 static void
 475 call_rcu_busted(struct rcu_head *head, rcu_callback_t func)
 476 {
 477         /* This is a deliberate bug for testing purposes only! */
 478         func(head);
 479 }
 480
 481 static struct rcu_torture_ops rcu_busted_ops = {
 482         .ttype          = INVALID_RCU_FLAVOR,
 483         .init           = rcu_sync_torture_init,
 484         .readlock       = rcu_torture_read_lock,
 485         .read_delay     = rcu_read_delay,  /* just reuse rcu's version. */
 486         .readunlock     = rcu_torture_read_unlock,
 487         .started        = rcu_no_completed,
 488         .completed      = rcu_no_completed,
 489         .deferred_free  = rcu_busted_torture_deferred_free,
 490         .sync           = synchronize_rcu_busted,
 491         .exp_sync       = synchronize_rcu_busted,
 492         .call           = call_rcu_busted,
 493         .cb_barrier     = NULL,
 494         .fqs            = NULL,
 495         .stats          = NULL,
 496         .irq_capable    = 1,
 497         .name           = "rcu_busted"
 498 };
 499
 500 /*
 501  * Definitions for srcu torture testing.
 502  */
 503
 504 DEFINE_STATIC_SRCU(srcu_ctl);
 505 static struct srcu_struct srcu_ctld;
 506 static struct srcu_struct *srcu_ctlp = &srcu_ctl;
 507
 508 static int srcu_torture_read_lock(void) __acquires(srcu_ctlp)
 509 {
 510         return srcu_read_lock(srcu_ctlp);
 511 }
 512
 513 static void srcu_read_delay(struct torture_random_state *rrsp)
 514 {
 515         long delay;
 516         const long uspertick = 1000000 / HZ;
 517         const long longdelay = 10;
 518
 519         /* We want there to be long-running readers, but not all the time. */
 520
 521         delay = torture_random(rrsp) %
 522                 (nrealreaders * 2 * longdelay * uspertick);
 523         if (!delay)
 524                 schedule_timeout_interruptible(longdelay);
 525         else
 526                 rcu_read_delay(rrsp);
 527 }
 528
 529 static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp)
 530 {
 531         srcu_read_unlock(srcu_ctlp, idx);
 532 }
 533
 534 static unsigned long srcu_torture_completed(void)
 535 {
 536         return srcu_batches_completed(srcu_ctlp);
 537 }
 538
 539 static void srcu_torture_deferred_free(struct rcu_torture *rp)
 540 {
 541         call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
 542 }
 543
 544 static void srcu_torture_synchronize(void)
 545 {
 546         synchronize_srcu(srcu_ctlp);
 547 }
 548
 549 static void srcu_torture_call(struct rcu_head *head,
 550                               rcu_callback_t func)
 551 {
 552         call_srcu(srcu_ctlp, head, func);
 553 }
 554
 555 static void srcu_torture_barrier(void)
 556 {
 557         srcu_barrier(srcu_ctlp);
 558 }
 559
 560 static void srcu_torture_stats(void)
 561 {
 562         int __maybe_unused cpu;
 563         int idx;
 564
 565 #if defined(CONFIG_TREE_SRCU) || defined(CONFIG_CLASSIC_SRCU)
 566 #ifdef CONFIG_TREE_SRCU
 567         idx = srcu_ctlp->srcu_idx & 0x1;
 568 #else /* #ifdef CONFIG_TREE_SRCU */
 569         idx = srcu_ctlp->completed & 0x1;
 570 #endif /* #else #ifdef CONFIG_TREE_SRCU */
 571         pr_alert("%s%s Tree SRCU per-CPU(idx=%d):",
 572                  torture_type, TORTURE_FLAG, idx);
 573         for_each_possible_cpu(cpu) {
 574                 unsigned long l0, l1;
 575                 unsigned long u0, u1;
 576                 long c0, c1;
 577 #ifdef CONFIG_TREE_SRCU
 578                 struct srcu_data *counts;
 579
 580                 counts = per_cpu_ptr(srcu_ctlp->sda, cpu);
 581                 u0 = counts->srcu_unlock_count[!idx];
 582                 u1 = counts->srcu_unlock_count[idx];
 583 #else /* #ifdef CONFIG_TREE_SRCU */
 584                 struct srcu_array *counts;
 585
 586                 counts = per_cpu_ptr(srcu_ctlp->per_cpu_ref, cpu);
 587                 u0 = counts->unlock_count[!idx];
 588                 u1 = counts->unlock_count[idx];
 589 #endif /* #else #ifdef CONFIG_TREE_SRCU */
 590
 591                 /*
 592                  * Make sure that a lock is always counted if the corresponding
 593                  * unlock is counted.
 594                  */
 595                 smp_rmb();
 596
 597 #ifdef CONFIG_TREE_SRCU
 598                 l0 = counts->srcu_lock_count[!idx];
 599                 l1 = counts->srcu_lock_count[idx];
 600 #else /* #ifdef CONFIG_TREE_SRCU */
 601                 l0 = counts->lock_count[!idx];
 602                 l1 = counts->lock_count[idx];
 603 #endif /* #else #ifdef CONFIG_TREE_SRCU */
 604
 605                 c0 = l0 - u0;
 606                 c1 = l1 - u1;
 607                 pr_cont(" %d(%ld,%ld)", cpu, c0, c1);
 608         }
 609         pr_cont("\n");
 610 #elif defined(CONFIG_TINY_SRCU)
 611         idx = READ_ONCE(srcu_ctlp->srcu_idx) & 0x1;
 612         pr_alert("%s%s Tiny SRCU per-CPU(idx=%d): (%d,%d)\n",
 613                  torture_type, TORTURE_FLAG, idx,
 614                  READ_ONCE(srcu_ctlp->srcu_lock_nesting[!idx]),
 615                  READ_ONCE(srcu_ctlp->srcu_lock_nesting[idx]));
 616 #endif
 617 }
 618
 619 static void srcu_torture_synchronize_expedited(void)
 620 {
 621         synchronize_srcu_expedited(srcu_ctlp);
 622 }
 623
 624 static struct rcu_torture_ops srcu_ops = {
 625         .ttype          = SRCU_FLAVOR,
 626         .init           = rcu_sync_torture_init,
 627         .readlock       = srcu_torture_read_lock,
 628         .read_delay     = srcu_read_delay,
 629         .readunlock     = srcu_torture_read_unlock,
 630         .started        = NULL,
 631         .completed      = srcu_torture_completed,
 632         .deferred_free  = srcu_torture_deferred_free,
 633         .sync           = srcu_torture_synchronize,
 634         .exp_sync       = srcu_torture_synchronize_expedited,
 635         .call           = srcu_torture_call,
 636         .cb_barrier     = srcu_torture_barrier,
 637         .stats          = srcu_torture_stats,
 638         .name           = "srcu"
 639 };
 640
 641 static void srcu_torture_init(void)
 642 {
 643         rcu_sync_torture_init();
 644         WARN_ON(init_srcu_struct(&srcu_ctld));
 645         srcu_ctlp = &srcu_ctld;
 646 }
 647
 648 static void srcu_torture_cleanup(void)
 649 {
 650         cleanup_srcu_struct(&srcu_ctld);
 651         srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
 652 }
 653
 654 /* As above, but dynamically allocated. */
 655 static struct rcu_torture_ops srcud_ops = {
 656         .ttype          = SRCU_FLAVOR,
 657         .init           = srcu_torture_init,
 658         .cleanup        = srcu_torture_cleanup,
 659         .readlock       = srcu_torture_read_lock,
 660         .read_delay     = srcu_read_delay,
 661         .readunlock     = srcu_torture_read_unlock,
 662         .started        = NULL,
 663         .completed      = srcu_torture_completed,
 664         .deferred_free  = srcu_torture_deferred_free,
 665         .sync           = srcu_torture_synchronize,
 666         .exp_sync       = srcu_torture_synchronize_expedited,
 667         .call           = srcu_torture_call,
 668         .cb_barrier     = srcu_torture_barrier,
 669         .stats          = srcu_torture_stats,
 670         .name           = "srcud"
 671 };
 672
 673 /*
 674  * Definitions for sched torture testing.
 675  */
 676
 677 static int sched_torture_read_lock(void)
 678 {
 679         preempt_disable();
 680         return 0;
 681 }
 682
 683 static void sched_torture_read_unlock(int idx)
 684 {
 685         preempt_enable();
 686 }
 687
 688 static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
 689 {
 690         call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
 691 }
 692
 693 static struct rcu_torture_ops sched_ops = {
 694         .ttype          = RCU_SCHED_FLAVOR,
 695         .init           = rcu_sync_torture_init,
 696         .readlock       = sched_torture_read_lock,
 697         .read_delay     = rcu_read_delay,  /* just reuse rcu's version. */
 698         .readunlock     = sched_torture_read_unlock,
 699         .started        = rcu_batches_started_sched,
 700         .completed      = rcu_batches_completed_sched,
 701         .deferred_free  = rcu_sched_torture_deferred_free,
 702         .sync           = synchronize_sched,
 703         .exp_sync       = synchronize_sched_expedited,
 704         .get_state      = get_state_synchronize_sched,
 705         .cond_sync      = cond_synchronize_sched,
 706         .call           = call_rcu_sched,
 707         .cb_barrier     = rcu_barrier_sched,
 708         .fqs            = rcu_sched_force_quiescent_state,
 709         .stats          = NULL,
 710         .irq_capable    = 1,
 711         .name           = "sched"
 712 };
 713
 714 #ifdef CONFIG_TASKS_RCU
 715
 716 /*
 717  * Definitions for RCU-tasks torture testing.
 718  */
 719
 720 static int tasks_torture_read_lock(void)
 721 {
 722         return 0;
 723 }
 724
 725 static void tasks_torture_read_unlock(int idx)
 726 {
 727 }
 728
 729 static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
 730 {
 731         call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
 732 }
 733
 734 static struct rcu_torture_ops tasks_ops = {
 735         .ttype          = RCU_TASKS_FLAVOR,
 736         .init           = rcu_sync_torture_init,
 737         .readlock       = tasks_torture_read_lock,
 738         .read_delay     = rcu_read_delay,  /* just reuse rcu's version. */
 739         .readunlock     = tasks_torture_read_unlock,
 740         .started        = rcu_no_completed,
 741         .completed      = rcu_no_completed,
 742         .deferred_free  = rcu_tasks_torture_deferred_free,
 743         .sync           = synchronize_rcu_tasks,
 744         .exp_sync       = synchronize_rcu_tasks,
 745         .call           = call_rcu_tasks,
 746         .cb_barrier     = rcu_barrier_tasks,
 747         .fqs            = NULL,
 748         .stats          = NULL,
 749         .irq_capable    = 1,
 750         .name           = "tasks"
 751 };
 752
 753 #define RCUTORTURE_TASKS_OPS &tasks_ops,
 754
 755 static bool __maybe_unused torturing_tasks(void)
 756 {
 757         return cur_ops == &tasks_ops;
 758 }
 759
 760 #else /* #ifdef CONFIG_TASKS_RCU */
 761
 762 #define RCUTORTURE_TASKS_OPS
 763
 764 static bool __maybe_unused torturing_tasks(void)
 765 {
 766         return false;
 767 }
 768
 769 #endif /* #else #ifdef CONFIG_TASKS_RCU */
 770
 771 /*
 772  * RCU torture priority-boost testing.  Runs one real-time thread per
 773  * CPU for moderate bursts, repeatedly registering RCU callbacks and
 774  * spinning waiting for them to be invoked.  If a given callback takes
 775  * too long to be invoked, we assume that priority inversion has occurred.
 776  */
 777
 778 struct rcu_boost_inflight {
 779         struct rcu_head rcu;
 780         int inflight;
 781 };
 782
 783 static void rcu_torture_boost_cb(struct rcu_head *head)
 784 {
 785         struct rcu_boost_inflight *rbip =
 786                 container_of(head, struct rcu_boost_inflight, rcu);
 787
 788         /* Ensure RCU-core accesses precede clearing ->inflight */
 789         smp_store_release(&rbip->inflight, 0);
 790 }
 791
 792 static int rcu_torture_boost(void *arg)
 793 {
 794         unsigned long call_rcu_time;
 795         unsigned long endtime;
 796         unsigned long oldstarttime;
 797         struct rcu_boost_inflight rbi = { .inflight = 0 };
 798         struct sched_param sp;
 799
 800         VERBOSE_TOROUT_STRING("rcu_torture_boost started");
 801
 802         /* Set real-time priority. */
 803         sp.sched_priority = 1;
 804         if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
 805                 VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!");
 806                 n_rcu_torture_boost_rterror++;
 807         }
 808
 809         init_rcu_head_on_stack(&rbi.rcu);
 810         /* Each pass through the following loop does one boost-test cycle. */
 811         do {
 812                 /* Wait for the next test interval. */
 813                 oldstarttime = boost_starttime;
 814                 while (ULONG_CMP_LT(jiffies, oldstarttime)) {
 815                         schedule_timeout_interruptible(oldstarttime - jiffies);
 816                         stutter_wait("rcu_torture_boost");
 817                         if (torture_must_stop())
 818                                 goto checkwait;
 819                 }
 820
 821                 /* Do one boost-test interval. */
 822                 endtime = oldstarttime + test_boost_duration * HZ;
 823                 call_rcu_time = jiffies;
 824                 while (ULONG_CMP_LT(jiffies, endtime)) {
 825                         /* If we don't have a callback in flight, post one. */
 826                         if (!smp_load_acquire(&rbi.inflight)) {
 827                                 /* RCU core before ->inflight = 1. */
 828                                 smp_store_release(&rbi.inflight, 1);
 829                                 call_rcu(&rbi.rcu, rcu_torture_boost_cb);
 830                                 if (jiffies - call_rcu_time >
 831                                          test_boost_duration * HZ - HZ / 2) {
 832                                         VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
 833                                         n_rcu_torture_boost_failure++;
 834                                 }
 835                                 call_rcu_time = jiffies;
 836                         }
 837                         stutter_wait("rcu_torture_boost");
 838                         if (torture_must_stop())
 839                                 goto checkwait;
 840                 }
 841
 842                 /*
 843                  * Set the start time of the next test interval.
 844                  * Yes, this is vulnerable to long delays, but such
 845                  * delays simply cause a false negative for the next
 846                  * interval.  Besides, we are running at RT priority,
 847                  * so delays should be relatively rare.
 848                  */
 849                 while (oldstarttime == boost_starttime &&
 850                        !kthread_should_stop()) {
 851                         if (mutex_trylock(&boost_mutex)) {
 852                                 boost_starttime = jiffies +
 853                                                   test_boost_interval * HZ;
 854                                 n_rcu_torture_boosts++;
 855                                 mutex_unlock(&boost_mutex);
 856                                 break;
 857                         }
 858                         schedule_timeout_uninterruptible(1);
 859                 }
 860
 861                 /* Go do the stutter. */
 862 checkwait:      stutter_wait("rcu_torture_boost");
 863         } while (!torture_must_stop());
 864
 865         /* Clean up and exit. */
 866         while (!kthread_should_stop() || smp_load_acquire(&rbi.inflight)) {
 867                 torture_shutdown_absorb("rcu_torture_boost");
 868                 schedule_timeout_uninterruptible(1);
 869         }
 870         destroy_rcu_head_on_stack(&rbi.rcu);
 871         torture_kthread_stopping("rcu_torture_boost");
 872         return 0;
 873 }
 874
 875 static void rcu_torture_cbflood_cb(struct rcu_head *rhp)
 876 {
 877 }
 878
 879 /*
 880  * RCU torture callback-flood kthread.  Repeatedly induces bursts of calls
 881  * to call_rcu() or analogous, increasing the probability of occurrence
 882  * of callback-overflow corner cases.
 883  */
 884 static int
 885 rcu_torture_cbflood(void *arg)
 886 {
 887         int err = 1;
 888         int i;
 889         int j;
 890         struct rcu_head *rhp;
 891
 892         if (cbflood_n_per_burst > 0 &&
 893             cbflood_inter_holdoff > 0 &&
 894             cbflood_intra_holdoff > 0 &&
 895             cur_ops->call &&
 896             cur_ops->cb_barrier) {
 897                 rhp = vmalloc(sizeof(*rhp) *
 898                               cbflood_n_burst * cbflood_n_per_burst);
 899                 err = !rhp;
 900         }
 901         if (err) {
 902                 VERBOSE_TOROUT_STRING("rcu_torture_cbflood disabled: Bad args or OOM");
 903                 goto wait_for_stop;
 904         }
 905         VERBOSE_TOROUT_STRING("rcu_torture_cbflood task started");
 906         do {
 907                 schedule_timeout_interruptible(cbflood_inter_holdoff);
 908                 atomic_long_inc(&n_cbfloods);
 909                 WARN_ON(signal_pending(current));
 910                 for (i = 0; i < cbflood_n_burst; i++) {
 911                         for (j = 0; j < cbflood_n_per_burst; j++) {
 912                                 cur_ops->call(&rhp[i * cbflood_n_per_burst + j],
 913                                               rcu_torture_cbflood_cb);
 914                         }
 915                         schedule_timeout_interruptible(cbflood_intra_holdoff);
 916                         WARN_ON(signal_pending(current));
 917                 }
 918                 cur_ops->cb_barrier();
 919                 stutter_wait("rcu_torture_cbflood");
 920         } while (!torture_must_stop());
 921         vfree(rhp);
 922 wait_for_stop:
 923         torture_kthread_stopping("rcu_torture_cbflood");
 924         return 0;
 925 }
 926
 927 /*
 928  * RCU torture force-quiescent-state kthread.  Repeatedly induces
 929  * bursts of calls to force_quiescent_state(), increasing the probability
 930  * of occurrence of some important types of race conditions.
 931  */
 932 static int
 933 rcu_torture_fqs(void *arg)
 934 {
 935         unsigned long fqs_resume_time;
 936         int fqs_burst_remaining;
 937
 938         VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
 939         do {
 940                 fqs_resume_time = jiffies + fqs_stutter * HZ;
 941                 while (ULONG_CMP_LT(jiffies, fqs_resume_time) &&
 942                        !kthread_should_stop()) {
 943                         schedule_timeout_interruptible(1);
 944                 }
 945                 fqs_burst_remaining = fqs_duration;
 946                 while (fqs_burst_remaining > 0 &&
 947                        !kthread_should_stop()) {
 948                         cur_ops->fqs();
 949                         udelay(fqs_holdoff);
 950                         fqs_burst_remaining -= fqs_holdoff;
 951                 }
 952                 stutter_wait("rcu_torture_fqs");
 953         } while (!torture_must_stop());
 954         torture_kthread_stopping("rcu_torture_fqs");
 955         return 0;
 956 }
 957
 958 /*
 959  * RCU torture writer kthread.  Repeatedly substitutes a new structure
 960  * for that pointed to by rcu_torture_current, freeing the old structure
 961  * after a series of grace periods (the "pipeline").
 962  */
 963 static int
 964 rcu_torture_writer(void *arg)
 965 {
 966         bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
 967         int expediting = 0;
 968         unsigned long gp_snap;
 969         bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal;
 970         bool gp_sync1 = gp_sync;
 971         int i;
 972         struct rcu_torture *rp;
 973         struct rcu_torture *old_rp;
 974         static DEFINE_TORTURE_RANDOM(rand);
 975         int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC,
 976                            RTWS_COND_GET, RTWS_SYNC };
 977         int nsynctypes = 0;
 978
 979         VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
 980         if (!can_expedite) {
 981                 pr_alert("%s" TORTURE_FLAG
 982                          " GP expediting controlled from boot/sysfs for %s,\n",
 983                          torture_type, cur_ops->name);
 984                 pr_alert("%s" TORTURE_FLAG
 985                          " Disabled dynamic grace-period expediting.\n",
 986                          torture_type);
 987         }
 988
 989         /* Initialize synctype[] array.  If none set, take default. */
 990         if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync1)
 991                 gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true;
 992         if (gp_cond1 && cur_ops->get_state && cur_ops->cond_sync)
 993                 synctype[nsynctypes++] = RTWS_COND_GET;
 994         else if (gp_cond && (!cur_ops->get_state || !cur_ops->cond_sync))
 995                 pr_alert("rcu_torture_writer: gp_cond without primitives.\n");
 996         if (gp_exp1 && cur_ops->exp_sync)
 997                 synctype[nsynctypes++] = RTWS_EXP_SYNC;
 998         else if (gp_exp && !cur_ops->exp_sync)
 999                 pr_alert("rcu_torture_writer: gp_exp without primitives.\n");
1000         if (gp_normal1 && cur_ops->deferred_free)
1001                 synctype[nsynctypes++] = RTWS_DEF_FREE;
1002         else if (gp_normal && !cur_ops->deferred_free)
1003                 pr_alert("rcu_torture_writer: gp_normal without primitives.\n");
1004         if (gp_sync1 && cur_ops->sync)
1005                 synctype[nsynctypes++] = RTWS_SYNC;
1006         else if (gp_sync && !cur_ops->sync)
1007                 pr_alert("rcu_torture_writer: gp_sync without primitives.\n");
1008         if (WARN_ONCE(nsynctypes == 0,
1009                       "rcu_torture_writer: No update-side primitives.\n")) {
1010                 /*
1011                  * No updates primitives, so don't try updating.
1012                  * The resulting test won't be testing much, hence the
1013                  * above WARN_ONCE().
1014                  */
1015                 rcu_torture_writer_state = RTWS_STOPPING;
1016                 torture_kthread_stopping("rcu_torture_writer");
1017         }
1018
1019         do {
1020                 rcu_torture_writer_state = RTWS_FIXED_DELAY;
1021                 schedule_timeout_uninterruptible(1);
1022                 rp = rcu_torture_alloc();
1023                 if (rp == NULL)
1024                         continue;
1025                 rp->rtort_pipe_count = 0;
1026                 rcu_torture_writer_state = RTWS_DELAY;
1027                 udelay(torture_random(&rand) & 0x3ff);
1028                 rcu_torture_writer_state = RTWS_REPLACE;
1029                 old_rp = rcu_dereference_check(rcu_torture_current,
1030                                                current == writer_task);
1031                 rp->rtort_mbtest = 1;
1032                 rcu_assign_pointer(rcu_torture_current, rp);
1033                 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
1034                 if (old_rp) {
1035                         i = old_rp->rtort_pipe_count;
1036                         if (i > RCU_TORTURE_PIPE_LEN)
1037                                 i = RCU_TORTURE_PIPE_LEN;
1038                         atomic_inc(&rcu_torture_wcount[i]);
1039                         old_rp->rtort_pipe_count++;
1040                         switch (synctype[torture_random(&rand) % nsynctypes]) {
1041                         case RTWS_DEF_FREE:
1042                                 rcu_torture_writer_state = RTWS_DEF_FREE;
1043                                 cur_ops->deferred_free(old_rp);
1044                                 break;
1045                         case RTWS_EXP_SYNC:
1046                                 rcu_torture_writer_state = RTWS_EXP_SYNC;
1047                                 cur_ops->exp_sync();
1048                                 rcu_torture_pipe_update(old_rp);
1049                                 break;
1050                         case RTWS_COND_GET:
1051                                 rcu_torture_writer_state = RTWS_COND_GET;
1052                                 gp_snap = cur_ops->get_state();
1053                                 i = torture_random(&rand) % 16;
1054                                 if (i != 0)
1055                                         schedule_timeout_interruptible(i);
1056                                 udelay(torture_random(&rand) % 1000);
1057                                 rcu_torture_writer_state = RTWS_COND_SYNC;
1058                                 cur_ops->cond_sync(gp_snap);
1059                                 rcu_torture_pipe_update(old_rp);
1060                                 break;
1061                         case RTWS_SYNC:
1062                                 rcu_torture_writer_state = RTWS_SYNC;
1063                                 cur_ops->sync();
1064                                 rcu_torture_pipe_update(old_rp);
1065                                 break;
1066                         default:
1067                                 WARN_ON_ONCE(1);
1068                                 break;
1069                         }
1070                 }
1071                 rcutorture_record_progress(++rcu_torture_current_version);
1072                 /* Cycle through nesting levels of rcu_expedite_gp() calls. */
1073                 if (can_expedite &&
1074                     !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
1075                         WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
1076                         if (expediting >= 0)
1077                                 rcu_expedite_gp();
1078                         else
1079                                 rcu_unexpedite_gp();
1080                         if (++expediting > 3)
1081                                 expediting = -expediting;
1082                 }
1083                 rcu_torture_writer_state = RTWS_STUTTER;
1084                 stutter_wait("rcu_torture_writer");
1085         } while (!torture_must_stop());
1086         /* Reset expediting back to unexpedited. */
1087         if (expediting > 0)
1088                 expediting = -expediting;
1089         while (can_expedite && expediting++ < 0)
1090                 rcu_unexpedite_gp();
1091         WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
1092         rcu_torture_writer_state = RTWS_STOPPING;
1093         torture_kthread_stopping("rcu_torture_writer");
1094         return 0;
1095 }
1096
1097 /*
1098  * RCU torture fake writer kthread.  Repeatedly calls sync, with a random
1099  * delay between calls.
1100  */
1101 static int
1102 rcu_torture_fakewriter(void *arg)
1103 {
1104         DEFINE_TORTURE_RANDOM(rand);
1105
1106         VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1107         set_user_nice(current, MAX_NICE);
1108
1109         do {
1110                 schedule_timeout_uninterruptible(1 + torture_random(&rand)%10);
1111                 udelay(torture_random(&rand) & 0x3ff);
1112                 if (cur_ops->cb_barrier != NULL &&
1113                     torture_random(&rand) % (nfakewriters * 8) == 0) {
1114                         cur_ops->cb_barrier();
1115                 } else if (gp_normal == gp_exp) {
1116                         if (torture_random(&rand) & 0x80)
1117                                 cur_ops->sync();
1118                         else
1119                                 cur_ops->exp_sync();
1120                 } else if (gp_normal) {
1121                         cur_ops->sync();
1122                 } else {
1123                         cur_ops->exp_sync();
1124                 }
1125                 stutter_wait("rcu_torture_fakewriter");
1126         } while (!torture_must_stop());
1127
1128         torture_kthread_stopping("rcu_torture_fakewriter");
1129         return 0;
1130 }
1131
1132 /*
1133  * RCU torture reader from timer handler.  Dereferences rcu_torture_current,
1134  * incrementing the corresponding element of the pipeline array.  The
1135  * counter in the element should never be greater than 1, otherwise, the
1136  * RCU implementation is broken.
1137  */
1138 static void rcu_torture_timer(unsigned long unused)
1139 {
1140         int idx;
1141         unsigned long started;
1142         unsigned long completed;
1143         static DEFINE_TORTURE_RANDOM(rand);
1144         static DEFINE_SPINLOCK(rand_lock);
1145         struct rcu_torture *p;
1146         int pipe_count;
1147         unsigned long long ts;
1148
1149         idx = cur_ops->readlock();
1150         if (cur_ops->started)
1151                 started = cur_ops->started();
1152         else
1153                 started = cur_ops->completed();
1154         ts = rcu_trace_clock_local();
1155         p = rcu_dereference_check(rcu_torture_current,
1156                                   rcu_read_lock_bh_held() ||
1157                                   rcu_read_lock_sched_held() ||
1158                                   srcu_read_lock_held(srcu_ctlp) ||
1159                                   torturing_tasks());
1160         if (p == NULL) {
1161                 /* Leave because rcu_torture_writer is not yet underway */
1162                 cur_ops->readunlock(idx);
1163                 return;
1164         }
1165         if (p->rtort_mbtest == 0)
1166                 atomic_inc(&n_rcu_torture_mberror);
1167         spin_lock(&rand_lock);
1168         cur_ops->read_delay(&rand);
1169         n_rcu_torture_timers++;
1170         spin_unlock(&rand_lock);
1171         preempt_disable();
1172         pipe_count = p->rtort_pipe_count;
1173         if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1174                 /* Should not happen, but... */
1175                 pipe_count = RCU_TORTURE_PIPE_LEN;
1176         }
1177         completed = cur_ops->completed();
1178         if (pipe_count > 1) {
1179                 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, ts,
1180                                           started, completed);
1181                 rcu_ftrace_dump(DUMP_ALL);
1182         }
1183         __this_cpu_inc(rcu_torture_count[pipe_count]);
1184         completed = completed - started;
1185         if (cur_ops->started)
1186                 completed++;
1187         if (completed > RCU_TORTURE_PIPE_LEN) {
1188                 /* Should not happen, but... */
1189                 completed = RCU_TORTURE_PIPE_LEN;
1190         }
1191         __this_cpu_inc(rcu_torture_batch[completed]);
1192         preempt_enable();
1193         cur_ops->readunlock(idx);
1194 }
1195
1196 /*
1197  * RCU torture reader kthread.  Repeatedly dereferences rcu_torture_current,
1198  * incrementing the corresponding element of the pipeline array.  The
1199  * counter in the element should never be greater than 1, otherwise, the
1200  * RCU implementation is broken.
1201  */
1202 static int
1203 rcu_torture_reader(void *arg)
1204 {
1205         unsigned long started;
1206         unsigned long completed;
1207         int idx;
1208         DEFINE_TORTURE_RANDOM(rand);
1209         struct rcu_torture *p;
1210         int pipe_count;
1211         struct timer_list t;
1212         unsigned long long ts;
1213
1214         VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
1215         set_user_nice(current, MAX_NICE);
1216         if (irqreader && cur_ops->irq_capable)
1217                 setup_timer_on_stack(&t, rcu_torture_timer, 0);
1218
1219         do {
1220                 if (irqreader && cur_ops->irq_capable) {
1221                         if (!timer_pending(&t))
1222                                 mod_timer(&t, jiffies + 1);
1223                 }
1224                 idx = cur_ops->readlock();
1225                 if (cur_ops->started)
1226                         started = cur_ops->started();
1227                 else
1228                         started = cur_ops->completed();
1229                 ts = rcu_trace_clock_local();
1230                 p = rcu_dereference_check(rcu_torture_current,
1231                                           rcu_read_lock_bh_held() ||
1232                                           rcu_read_lock_sched_held() ||
1233                                           srcu_read_lock_held(srcu_ctlp) ||
1234                                           torturing_tasks());
1235                 if (p == NULL) {
1236                         /* Wait for rcu_torture_writer to get underway */
1237                         cur_ops->readunlock(idx);
1238                         schedule_timeout_interruptible(HZ);
1239                         continue;
1240                 }
1241                 if (p->rtort_mbtest == 0)
1242                         atomic_inc(&n_rcu_torture_mberror);
1243                 cur_ops->read_delay(&rand);
1244                 preempt_disable();
1245                 pipe_count = p->rtort_pipe_count;
1246                 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1247                         /* Should not happen, but... */
1248                         pipe_count = RCU_TORTURE_PIPE_LEN;
1249                 }
1250                 completed = cur_ops->completed();
1251                 if (pipe_count > 1) {
1252                         do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
1253                                                   ts, started, completed);
1254                         rcu_ftrace_dump(DUMP_ALL);
1255                 }
1256                 __this_cpu_inc(rcu_torture_count[pipe_count]);
1257                 completed = completed - started;
1258                 if (cur_ops->started)
1259                         completed++;
1260                 if (completed > RCU_TORTURE_PIPE_LEN) {
1261                         /* Should not happen, but... */
1262                         completed = RCU_TORTURE_PIPE_LEN;
1263                 }
1264                 __this_cpu_inc(rcu_torture_batch[completed]);
1265                 preempt_enable();
1266                 cur_ops->readunlock(idx);
1267                 stutter_wait("rcu_torture_reader");
1268         } while (!torture_must_stop());
1269         if (irqreader && cur_ops->irq_capable) {
1270                 del_timer_sync(&t);
1271                 destroy_timer_on_stack(&t);
1272         }
1273         torture_kthread_stopping("rcu_torture_reader");
1274         return 0;
1275 }
1276
1277 /*
1278  * Print torture statistics.  Caller must ensure that there is only
1279  * one call to this function at a given time!!!  This is normally
1280  * accomplished by relying on the module system to only have one copy
1281  * of the module loaded, and then by giving the rcu_torture_stats
1282  * kthread full control (or the init/cleanup functions when rcu_torture_stats
1283  * thread is not running).
1284  */
1285 static void
1286 rcu_torture_stats_print(void)
1287 {
1288         int cpu;
1289         int i;
1290         long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1291         long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1292         static unsigned long rtcv_snap = ULONG_MAX;
1293         struct task_struct *wtp;
1294
1295         for_each_possible_cpu(cpu) {
1296                 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1297                         pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
1298                         batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
1299                 }
1300         }
1301         for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
1302                 if (pipesummary[i] != 0)
1303                         break;
1304         }
1305
1306         pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1307         pr_cont("rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
1308                 rcu_torture_current,
1309                 rcu_torture_current_version,
1310                 list_empty(&rcu_torture_freelist),
1311                 atomic_read(&n_rcu_torture_alloc),
1312                 atomic_read(&n_rcu_torture_alloc_fail),
1313                 atomic_read(&n_rcu_torture_free));
1314         pr_cont("rtmbe: %d rtbe: %ld rtbke: %ld rtbre: %ld ",
1315                 atomic_read(&n_rcu_torture_mberror),
1316                 n_rcu_torture_barrier_error,
1317                 n_rcu_torture_boost_ktrerror,
1318                 n_rcu_torture_boost_rterror);
1319         pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
1320                 n_rcu_torture_boost_failure,
1321                 n_rcu_torture_boosts,
1322                 n_rcu_torture_timers);
1323         torture_onoff_stats();
1324         pr_cont("barrier: %ld/%ld:%ld ",
1325                 n_barrier_successes,
1326                 n_barrier_attempts,
1327                 n_rcu_torture_barrier_error);
1328         pr_cont("cbflood: %ld\n", atomic_long_read(&n_cbfloods));
1329
1330         pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1331         if (atomic_read(&n_rcu_torture_mberror) != 0 ||
1332             n_rcu_torture_barrier_error != 0 ||
1333             n_rcu_torture_boost_ktrerror != 0 ||
1334             n_rcu_torture_boost_rterror != 0 ||
1335             n_rcu_torture_boost_failure != 0 ||
1336             i > 1) {
1337                 pr_cont("%s", "!!! ");
1338                 atomic_inc(&n_rcu_torture_error);
1339                 WARN_ON_ONCE(1);
1340         }
1341         pr_cont("Reader Pipe: ");
1342         for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1343                 pr_cont(" %ld", pipesummary[i]);
1344         pr_cont("\n");
1345
1346         pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1347         pr_cont("Reader Batch: ");
1348         for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1349                 pr_cont(" %ld", batchsummary[i]);
1350         pr_cont("\n");
1351
1352         pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1353         pr_cont("Free-Block Circulation: ");
1354         for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1355                 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
1356         }
1357         pr_cont("\n");
1358
1359         if (cur_ops->stats)
1360                 cur_ops->stats();
1361         if (rtcv_snap == rcu_torture_current_version &&
1362             rcu_torture_current != NULL) {
1363                 int __maybe_unused flags = 0;
1364                 unsigned long __maybe_unused gpnum = 0;
1365                 unsigned long __maybe_unused completed = 0;
1366
1367                 rcutorture_get_gp_data(cur_ops->ttype,
1368                                        &flags, &gpnum, &completed);
1369                 srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp,
1370                                         &flags, &gpnum, &completed);
1371                 wtp = READ_ONCE(writer_task);
1372                 pr_alert("??? Writer stall state %s(%d) g%lu c%lu f%#x ->state %#lx\n",
1373                          rcu_torture_writer_state_getname(),
1374                          rcu_torture_writer_state,
1375                          gpnum, completed, flags,
1376                          wtp == NULL ? ~0UL : wtp->state);
1377                 show_rcu_gp_kthreads();
1378                 rcu_ftrace_dump(DUMP_ALL);
1379         }
1380         rtcv_snap = rcu_torture_current_version;
1381 }
1382
1383 /*
1384  * Periodically prints torture statistics, if periodic statistics printing
1385  * was specified via the stat_interval module parameter.
1386  */
1387 static int
1388 rcu_torture_stats(void *arg)
1389 {
1390         VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1391         do {
1392                 schedule_timeout_interruptible(stat_interval * HZ);
1393                 rcu_torture_stats_print();
1394                 torture_shutdown_absorb("rcu_torture_stats");
1395         } while (!torture_must_stop());
1396         torture_kthread_stopping("rcu_torture_stats");
1397         return 0;
1398 }
1399
1400 static inline void
1401 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1402 {
1403         pr_alert("%s" TORTURE_FLAG
1404                  "--- %s: nreaders=%d nfakewriters=%d "
1405                  "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1406                  "shuffle_interval=%d stutter=%d irqreader=%d "
1407                  "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1408                  "test_boost=%d/%d test_boost_interval=%d "
1409                  "test_boost_duration=%d shutdown_secs=%d "
1410                  "stall_cpu=%d stall_cpu_holdoff=%d "
1411                  "n_barrier_cbs=%d "
1412                  "onoff_interval=%d onoff_holdoff=%d\n",
1413                  torture_type, tag, nrealreaders, nfakewriters,
1414                  stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1415                  stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1416                  test_boost, cur_ops->can_boost,
1417                  test_boost_interval, test_boost_duration, shutdown_secs,
1418                  stall_cpu, stall_cpu_holdoff,
1419                  n_barrier_cbs,
1420                  onoff_interval, onoff_holdoff);
1421 }
1422
1423 static int rcutorture_booster_cleanup(unsigned int cpu)
1424 {
1425         struct task_struct *t;
1426
1427         if (boost_tasks[cpu] == NULL)
1428                 return 0;
1429         mutex_lock(&boost_mutex);
1430         t = boost_tasks[cpu];
1431         boost_tasks[cpu] = NULL;
1432         mutex_unlock(&boost_mutex);
1433
1434         /* This must be outside of the mutex, otherwise deadlock! */
1435         torture_stop_kthread(rcu_torture_boost, t);
1436         return 0;
1437 }
1438
1439 static int rcutorture_booster_init(unsigned int cpu)
1440 {
1441         int retval;
1442
1443         if (boost_tasks[cpu] != NULL)
1444                 return 0;  /* Already created, nothing more to do. */
1445
1446         /* Don't allow time recalculation while creating a new task. */
1447         mutex_lock(&boost_mutex);
1448         VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
1449         boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
1450                                                   cpu_to_node(cpu),
1451                                                   "rcu_torture_boost");
1452         if (IS_ERR(boost_tasks[cpu])) {
1453                 retval = PTR_ERR(boost_tasks[cpu]);
1454                 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
1455                 n_rcu_torture_boost_ktrerror++;
1456                 boost_tasks[cpu] = NULL;
1457                 mutex_unlock(&boost_mutex);
1458                 return retval;
1459         }
1460         kthread_bind(boost_tasks[cpu], cpu);
1461         wake_up_process(boost_tasks[cpu]);
1462         mutex_unlock(&boost_mutex);
1463         return 0;
1464 }
1465
1466 /*
1467  * CPU-stall kthread.  It waits as specified by stall_cpu_holdoff, then
1468  * induces a CPU stall for the time specified by stall_cpu.
1469  */
1470 static int rcu_torture_stall(void *args)
1471 {
1472         unsigned long stop_at;
1473
1474         VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
1475         if (stall_cpu_holdoff > 0) {
1476                 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
1477                 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
1478                 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
1479         }
1480         if (!kthread_should_stop()) {
1481                 stop_at = get_seconds() + stall_cpu;
1482                 /* RCU CPU stall is expected behavior in following code. */
1483                 pr_alert("rcu_torture_stall start.\n");
1484                 rcu_read_lock();
1485                 preempt_disable();
1486                 while (ULONG_CMP_LT(get_seconds(), stop_at))
1487                         continue;  /* Induce RCU CPU stall warning. */
1488                 preempt_enable();
1489                 rcu_read_unlock();
1490                 pr_alert("rcu_torture_stall end.\n");
1491         }
1492         torture_shutdown_absorb("rcu_torture_stall");
1493         while (!kthread_should_stop())
1494                 schedule_timeout_interruptible(10 * HZ);
1495         return 0;
1496 }
1497
1498 /* Spawn CPU-stall kthread, if stall_cpu specified. */
1499 static int __init rcu_torture_stall_init(void)
1500 {
1501         if (stall_cpu <= 0)
1502                 return 0;
1503         return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
1504 }
1505
1506 /* Callback function for RCU barrier testing. */
1507 static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
1508 {
1509         atomic_inc(&barrier_cbs_invoked);
1510 }
1511
1512 /* kthread function to register callbacks used to test RCU barriers. */
1513 static int rcu_torture_barrier_cbs(void *arg)
1514 {
1515         long myid = (long)arg;
1516         bool lastphase = 0;
1517         bool newphase;
1518         struct rcu_head rcu;
1519
1520         init_rcu_head_on_stack(&rcu);
1521         VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
1522         set_user_nice(current, MAX_NICE);
1523         do {
1524                 wait_event(barrier_cbs_wq[myid],
1525                            (newphase =
1526                             smp_load_acquire(&barrier_phase)) != lastphase ||
1527                            torture_must_stop());
1528                 lastphase = newphase;
1529                 if (torture_must_stop())
1530                         break;
1531                 /*
1532                  * The above smp_load_acquire() ensures barrier_phase load
1533                  * is ordered before the following ->call().
1534                  */
1535                 local_irq_disable(); /* Just to test no-irq call_rcu(). */
1536                 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
1537                 local_irq_enable();
1538                 if (atomic_dec_and_test(&barrier_cbs_count))
1539                         wake_up(&barrier_wq);
1540         } while (!torture_must_stop());
1541         if (cur_ops->cb_barrier != NULL)
1542                 cur_ops->cb_barrier();
1543         destroy_rcu_head_on_stack(&rcu);
1544         torture_kthread_stopping("rcu_torture_barrier_cbs");
1545         return 0;
1546 }
1547
1548 /* kthread function to drive and coordinate RCU barrier testing. */
1549 static int rcu_torture_barrier(void *arg)
1550 {
1551         int i;
1552
1553         VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
1554         do {
1555                 atomic_set(&barrier_cbs_invoked, 0);
1556                 atomic_set(&barrier_cbs_count, n_barrier_cbs);
1557                 /* Ensure barrier_phase ordered after prior assignments. */
1558                 smp_store_release(&barrier_phase, !barrier_phase);
1559                 for (i = 0; i < n_barrier_cbs; i++)
1560                         wake_up(&barrier_cbs_wq[i]);
1561                 wait_event(barrier_wq,
1562                            atomic_read(&barrier_cbs_count) == 0 ||
1563                            torture_must_stop());
1564                 if (torture_must_stop())
1565                         break;
1566                 n_barrier_attempts++;
1567                 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
1568                 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
1569                         n_rcu_torture_barrier_error++;
1570                         pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
1571                                atomic_read(&barrier_cbs_invoked),
1572                                n_barrier_cbs);
1573                         WARN_ON_ONCE(1);
1574                 }
1575                 n_barrier_successes++;
1576                 schedule_timeout_interruptible(HZ / 10);
1577         } while (!torture_must_stop());
1578         torture_kthread_stopping("rcu_torture_barrier");
1579         return 0;
1580 }
1581
1582 /* Initialize RCU barrier testing. */
1583 static int rcu_torture_barrier_init(void)
1584 {
1585         int i;
1586         int ret;
1587
1588         if (n_barrier_cbs <= 0)
1589                 return 0;
1590         if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
1591                 pr_alert("%s" TORTURE_FLAG
1592                          " Call or barrier ops missing for %s,\n",
1593                          torture_type, cur_ops->name);
1594                 pr_alert("%s" TORTURE_FLAG
1595                          " RCU barrier testing omitted from run.\n",
1596                          torture_type);
1597                 return 0;
1598         }
1599         atomic_set(&barrier_cbs_count, 0);
1600         atomic_set(&barrier_cbs_invoked, 0);
1601         barrier_cbs_tasks =
1602                 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_tasks[0]),
1603                         GFP_KERNEL);
1604         barrier_cbs_wq =
1605                 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_wq[0]),
1606                         GFP_KERNEL);
1607         if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
1608                 return -ENOMEM;
1609         for (i = 0; i < n_barrier_cbs; i++) {
1610                 init_waitqueue_head(&barrier_cbs_wq[i]);
1611                 ret = torture_create_kthread(rcu_torture_barrier_cbs,
1612                                              (void *)(long)i,
1613                                              barrier_cbs_tasks[i]);
1614                 if (ret)
1615                         return ret;
1616         }
1617         return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
1618 }
1619
1620 /* Clean up after RCU barrier testing. */
1621 static void rcu_torture_barrier_cleanup(void)
1622 {
1623         int i;
1624
1625         torture_stop_kthread(rcu_torture_barrier, barrier_task);
1626         if (barrier_cbs_tasks != NULL) {
1627                 for (i = 0; i < n_barrier_cbs; i++)
1628                         torture_stop_kthread(rcu_torture_barrier_cbs,
1629                                              barrier_cbs_tasks[i]);
1630                 kfree(barrier_cbs_tasks);
1631                 barrier_cbs_tasks = NULL;
1632         }
1633         if (barrier_cbs_wq != NULL) {
1634                 kfree(barrier_cbs_wq);
1635                 barrier_cbs_wq = NULL;
1636         }
1637 }
1638
1639 static enum cpuhp_state rcutor_hp;
1640
1641 static void
1642 rcu_torture_cleanup(void)
1643 {
1644         int i;
1645
1646         rcutorture_record_test_transition();
1647         if (torture_cleanup_begin()) {
1648                 if (cur_ops->cb_barrier != NULL)
1649                         cur_ops->cb_barrier();
1650                 return;
1651         }
1652
1653         rcu_torture_barrier_cleanup();
1654         torture_stop_kthread(rcu_torture_stall, stall_task);
1655         torture_stop_kthread(rcu_torture_writer, writer_task);
1656
1657         if (reader_tasks) {
1658                 for (i = 0; i < nrealreaders; i++)
1659                         torture_stop_kthread(rcu_torture_reader,
1660                                              reader_tasks[i]);
1661                 kfree(reader_tasks);
1662         }
1663         rcu_torture_current = NULL;
1664
1665         if (fakewriter_tasks) {
1666                 for (i = 0; i < nfakewriters; i++) {
1667                         torture_stop_kthread(rcu_torture_fakewriter,
1668                                              fakewriter_tasks[i]);
1669                 }
1670                 kfree(fakewriter_tasks);
1671                 fakewriter_tasks = NULL;
1672         }
1673
1674         torture_stop_kthread(rcu_torture_stats, stats_task);
1675         torture_stop_kthread(rcu_torture_fqs, fqs_task);
1676         for (i = 0; i < ncbflooders; i++)
1677                 torture_stop_kthread(rcu_torture_cbflood, cbflood_task[i]);
1678         if ((test_boost == 1 && cur_ops->can_boost) ||
1679             test_boost == 2)
1680                 cpuhp_remove_state(rcutor_hp);
1681
1682         /*
1683          * Wait for all RCU callbacks to fire, then do flavor-specific
1684          * cleanup operations.
1685          */
1686         if (cur_ops->cb_barrier != NULL)
1687                 cur_ops->cb_barrier();
1688         if (cur_ops->cleanup != NULL)
1689                 cur_ops->cleanup();
1690
1691         rcu_torture_stats_print();  /* -After- the stats thread is stopped! */
1692
1693         if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
1694                 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
1695         else if (torture_onoff_failures())
1696                 rcu_torture_print_module_parms(cur_ops,
1697                                                "End of test: RCU_HOTPLUG");
1698         else
1699                 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
1700         torture_cleanup_end();
1701 }
1702
1703 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1704 static void rcu_torture_leak_cb(struct rcu_head *rhp)
1705 {
1706 }
1707
1708 static void rcu_torture_err_cb(struct rcu_head *rhp)
1709 {
1710         /*
1711          * This -might- happen due to race conditions, but is unlikely.
1712          * The scenario that leads to this happening is that the
1713          * first of the pair of duplicate callbacks is queued,
1714          * someone else starts a grace period that includes that
1715          * callback, then the second of the pair must wait for the
1716          * next grace period.  Unlikely, but can happen.  If it
1717          * does happen, the debug-objects subsystem won't have splatted.
1718          */
1719         pr_alert("rcutorture: duplicated callback was invoked.\n");
1720 }
1721 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1722
1723 /*
1724  * Verify that double-free causes debug-objects to complain, but only
1725  * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y.  Otherwise, say that the test
1726  * cannot be carried out.
1727  */
1728 static void rcu_test_debug_objects(void)
1729 {
1730 #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1731         struct rcu_head rh1;
1732         struct rcu_head rh2;
1733
1734         init_rcu_head_on_stack(&rh1);
1735         init_rcu_head_on_stack(&rh2);
1736         pr_alert("rcutorture: WARN: Duplicate call_rcu() test starting.\n");
1737
1738         /* Try to queue the rh2 pair of callbacks for the same grace period. */
1739         preempt_disable(); /* Prevent preemption from interrupting test. */
1740         rcu_read_lock(); /* Make it impossible to finish a grace period. */
1741         call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
1742         local_irq_disable(); /* Make it harder to start a new grace period. */
1743         call_rcu(&rh2, rcu_torture_leak_cb);
1744         call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
1745         local_irq_enable();
1746         rcu_read_unlock();
1747         preempt_enable();
1748
1749         /* Wait for them all to get done so we can safely return. */
1750         rcu_barrier();
1751         pr_alert("rcutorture: WARN: Duplicate call_rcu() test complete.\n");
1752         destroy_rcu_head_on_stack(&rh1);
1753         destroy_rcu_head_on_stack(&rh2);
1754 #else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1755         pr_alert("rcutorture: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n");
1756 #endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1757 }
1758
1759 static int __init
1760 rcu_torture_init(void)
1761 {
1762         int i;
1763         int cpu;
1764         int firsterr = 0;
1765         static struct rcu_torture_ops *torture_ops[] = {
1766                 &rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops,
1767                 &sched_ops, RCUTORTURE_TASKS_OPS
1768         };
1769
1770         if (!torture_init_begin(torture_type, verbose, &torture_runnable))
1771                 return -EBUSY;
1772
1773         /* Process args and tell the world that the torturer is on the job. */
1774         for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1775                 cur_ops = torture_ops[i];
1776                 if (strcmp(torture_type, cur_ops->name) == 0)
1777                         break;
1778         }
1779         if (i == ARRAY_SIZE(torture_ops)) {
1780                 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
1781                          torture_type);
1782                 pr_alert("rcu-torture types:");
1783                 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1784                         pr_alert(" %s", torture_ops[i]->name);
1785                 pr_alert("\n");
1786                 firsterr = -EINVAL;
1787                 goto unwind;
1788         }
1789         if (cur_ops->fqs == NULL && fqs_duration != 0) {
1790                 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
1791                 fqs_duration = 0;
1792         }
1793         if (cur_ops->init)
1794                 cur_ops->init();
1795
1796         if (nreaders >= 0) {
1797                 nrealreaders = nreaders;
1798         } else {
1799                 nrealreaders = num_online_cpus() - 2 - nreaders;
1800                 if (nrealreaders <= 0)
1801                         nrealreaders = 1;
1802         }
1803         rcu_torture_print_module_parms(cur_ops, "Start of test");
1804
1805         /* Set up the freelist. */
1806
1807         INIT_LIST_HEAD(&rcu_torture_freelist);
1808         for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1809                 rcu_tortures[i].rtort_mbtest = 0;
1810                 list_add_tail(&rcu_tortures[i].rtort_free,
1811                               &rcu_torture_freelist);
1812         }
1813
1814         /* Initialize the statistics so that each run gets its own numbers. */
1815
1816         rcu_torture_current = NULL;
1817         rcu_torture_current_version = 0;
1818         atomic_set(&n_rcu_torture_alloc, 0);
1819         atomic_set(&n_rcu_torture_alloc_fail, 0);
1820         atomic_set(&n_rcu_torture_free, 0);
1821         atomic_set(&n_rcu_torture_mberror, 0);
1822         atomic_set(&n_rcu_torture_error, 0);
1823         n_rcu_torture_barrier_error = 0;
1824         n_rcu_torture_boost_ktrerror = 0;
1825         n_rcu_torture_boost_rterror = 0;
1826         n_rcu_torture_boost_failure = 0;
1827         n_rcu_torture_boosts = 0;
1828         for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1829                 atomic_set(&rcu_torture_wcount[i], 0);
1830         for_each_possible_cpu(cpu) {
1831                 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1832                         per_cpu(rcu_torture_count, cpu)[i] = 0;
1833                         per_cpu(rcu_torture_batch, cpu)[i] = 0;
1834                 }
1835         }
1836
1837         /* Start up the kthreads. */
1838
1839         firsterr = torture_create_kthread(rcu_torture_writer, NULL,
1840                                           writer_task);
1841         if (firsterr)
1842                 goto unwind;
1843         if (nfakewriters > 0) {
1844                 fakewriter_tasks = kzalloc(nfakewriters *
1845                                            sizeof(fakewriter_tasks[0]),
1846                                            GFP_KERNEL);
1847                 if (fakewriter_tasks == NULL) {
1848                         VERBOSE_TOROUT_ERRSTRING("out of memory");
1849                         firsterr = -ENOMEM;
1850                         goto unwind;
1851                 }
1852         }
1853         for (i = 0; i < nfakewriters; i++) {
1854                 firsterr = torture_create_kthread(rcu_torture_fakewriter,
1855                                                   NULL, fakewriter_tasks[i]);
1856                 if (firsterr)
1857                         goto unwind;
1858         }
1859         reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
1860                                GFP_KERNEL);
1861         if (reader_tasks == NULL) {
1862                 VERBOSE_TOROUT_ERRSTRING("out of memory");
1863                 firsterr = -ENOMEM;
1864                 goto unwind;
1865         }
1866         for (i = 0; i < nrealreaders; i++) {
1867                 firsterr = torture_create_kthread(rcu_torture_reader, NULL,
1868                                                   reader_tasks[i]);
1869                 if (firsterr)
1870                         goto unwind;
1871         }
1872         if (stat_interval > 0) {
1873                 firsterr = torture_create_kthread(rcu_torture_stats, NULL,
1874                                                   stats_task);
1875                 if (firsterr)
1876                         goto unwind;
1877         }
1878         if (test_no_idle_hz && shuffle_interval > 0) {
1879                 firsterr = torture_shuffle_init(shuffle_interval * HZ);
1880                 if (firsterr)
1881                         goto unwind;
1882         }
1883         if (stutter < 0)
1884                 stutter = 0;
1885         if (stutter) {
1886                 firsterr = torture_stutter_init(stutter * HZ);
1887                 if (firsterr)
1888                         goto unwind;
1889         }
1890         if (fqs_duration < 0)
1891                 fqs_duration = 0;
1892         if (fqs_duration) {
1893                 /* Create the fqs thread */
1894                 firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
1895                                                   fqs_task);
1896                 if (firsterr)
1897                         goto unwind;
1898         }
1899         if (test_boost_interval < 1)
1900                 test_boost_interval = 1;
1901         if (test_boost_duration < 2)
1902                 test_boost_duration = 2;
1903         if ((test_boost == 1 && cur_ops->can_boost) ||
1904             test_boost == 2) {
1905
1906                 boost_starttime = jiffies + test_boost_interval * HZ;
1907
1908                 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE",
1909                                              rcutorture_booster_init,
1910                                              rcutorture_booster_cleanup);
1911                 if (firsterr < 0)
1912                         goto unwind;
1913                 rcutor_hp = firsterr;
1914         }
1915         firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
1916         if (firsterr)
1917                 goto unwind;
1918         firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval * HZ);
1919         if (firsterr)
1920                 goto unwind;
1921         firsterr = rcu_torture_stall_init();
1922         if (firsterr)
1923                 goto unwind;
1924         firsterr = rcu_torture_barrier_init();
1925         if (firsterr)
1926                 goto unwind;
1927         if (object_debug)
1928                 rcu_test_debug_objects();
1929         if (cbflood_n_burst > 0) {
1930                 /* Create the cbflood threads */
1931                 ncbflooders = (num_online_cpus() + 3) / 4;
1932                 cbflood_task = kcalloc(ncbflooders, sizeof(*cbflood_task),
1933                                        GFP_KERNEL);
1934                 if (!cbflood_task) {
1935                         VERBOSE_TOROUT_ERRSTRING("out of memory");
1936                         firsterr = -ENOMEM;
1937                         goto unwind;
1938                 }
1939                 for (i = 0; i < ncbflooders; i++) {
1940                         firsterr = torture_create_kthread(rcu_torture_cbflood,
1941                                                           NULL,
1942                                                           cbflood_task[i]);
1943                         if (firsterr)
1944                                 goto unwind;
1945                 }
1946         }
1947         rcutorture_record_test_transition();
1948         torture_init_end();
1949         return 0;
1950
1951 unwind:
1952         torture_init_end();
1953         rcu_torture_cleanup();
1954         return firsterr;
1955 }
1956
1957 module_init(rcu_torture_init);
1958 module_exit(rcu_torture_cleanup);