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.h>
  36#include <linux/atomic.h>
  37#include <linux/bitops.h>
  38#include <linux/completion.h>
  39#include <linux/moduleparam.h>
  40#include <linux/percpu.h>
  41#include <linux/notifier.h>
  42#include <linux/reboot.h>
  43#include <linux/freezer.h>
  44#include <linux/cpu.h>
  45#include <linux/delay.h>
  46#include <linux/stat.h>
  47#include <linux/srcu.h>
  48#include <linux/slab.h>
  49#include <linux/trace_clock.h>
  50#include <asm/byteorder.h>
  51#include <linux/torture.h>
  52#include <linux/vmalloc.h>
  53
  54MODULE_LICENSE("GPL");
  55MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
  56
  57
  58torture_param(int, cbflood_inter_holdoff, HZ,
  59	      "Holdoff between floods (jiffies)");
  60torture_param(int, cbflood_intra_holdoff, 1,
  61	      "Holdoff between bursts (jiffies)");
  62torture_param(int, cbflood_n_burst, 3, "# bursts in flood, zero to disable");
  63torture_param(int, cbflood_n_per_burst, 20000,
  64	      "# callbacks per burst in flood");
  65torture_param(int, fqs_duration, 0,
  66	      "Duration of fqs bursts (us), 0 to disable");
  67torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
  68torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
  69torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
  70torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
  71torture_param(bool, gp_normal, false,
  72	     "Use normal (non-expedited) GP wait primitives");
  73torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
  74torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
  75torture_param(int, n_barrier_cbs, 0,
  76	     "# of callbacks/kthreads for barrier testing");
  77torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
  78torture_param(int, nreaders, -1, "Number of RCU reader threads");
  79torture_param(int, object_debug, 0,
  80	     "Enable debug-object double call_rcu() testing");
  81torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
  82torture_param(int, onoff_interval, 0,
  83	     "Time between CPU hotplugs (s), 0=disable");
  84torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
  85torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
  86torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
  87torture_param(int, stall_cpu_holdoff, 10,
  88	     "Time to wait before starting stall (s).");
  89torture_param(int, stat_interval, 60,
  90	     "Number of seconds between stats printk()s");
  91torture_param(int, stutter, 5, "Number of seconds to run/halt test");
  92torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
  93torture_param(int, test_boost_duration, 4,
  94	     "Duration of each boost test, seconds.");
  95torture_param(int, test_boost_interval, 7,
  96	     "Interval between boost tests, seconds.");
  97torture_param(bool, test_no_idle_hz, true,
  98	     "Test support for tickless idle CPUs");
  99torture_param(bool, verbose, true,
 100	     "Enable verbose debugging printk()s");
 101
 102static char *torture_type = "rcu";
 103module_param(torture_type, charp, 0444);
 104MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, ...)");
 105
 106static int nrealreaders;
 107static int ncbflooders;
 108static struct task_struct *writer_task;
 109static struct task_struct **fakewriter_tasks;
 110static struct task_struct **reader_tasks;
 111static struct task_struct *stats_task;
 112static struct task_struct **cbflood_task;
 113static struct task_struct *fqs_task;
 114static struct task_struct *boost_tasks[NR_CPUS];
 115static struct task_struct *stall_task;
 116static struct task_struct **barrier_cbs_tasks;
 117static struct task_struct *barrier_task;
 118
 119#define RCU_TORTURE_PIPE_LEN 10
 120
 121struct rcu_torture {
 122	struct rcu_head rtort_rcu;
 123	int rtort_pipe_count;
 124	struct list_head rtort_free;
 125	int rtort_mbtest;
 126};
 127
 128static LIST_HEAD(rcu_torture_freelist);
 129static struct rcu_torture __rcu *rcu_torture_current;
 130static unsigned long rcu_torture_current_version;
 131static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
 132static DEFINE_SPINLOCK(rcu_torture_lock);
 133static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count);
 134static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch);
 
 
 135static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
 136static atomic_t n_rcu_torture_alloc;
 137static atomic_t n_rcu_torture_alloc_fail;
 138static atomic_t n_rcu_torture_free;
 139static atomic_t n_rcu_torture_mberror;
 140static atomic_t n_rcu_torture_error;
 141static long n_rcu_torture_barrier_error;
 142static long n_rcu_torture_boost_ktrerror;
 143static long n_rcu_torture_boost_rterror;
 144static long n_rcu_torture_boost_failure;
 145static long n_rcu_torture_boosts;
 146static long n_rcu_torture_timers;
 147static long n_barrier_attempts;
 148static long n_barrier_successes;
 149static atomic_long_t n_cbfloods;
 150static struct list_head rcu_torture_removed;
 151
 152static int rcu_torture_writer_state;
 153#define RTWS_FIXED_DELAY	0
 154#define RTWS_DELAY		1
 155#define RTWS_REPLACE		2
 156#define RTWS_DEF_FREE		3
 157#define RTWS_EXP_SYNC		4
 158#define RTWS_COND_GET		5
 159#define RTWS_COND_SYNC		6
 160#define RTWS_SYNC		7
 161#define RTWS_STUTTER		8
 162#define RTWS_STOPPING		9
 163static const char * const rcu_torture_writer_state_names[] = {
 164	"RTWS_FIXED_DELAY",
 165	"RTWS_DELAY",
 166	"RTWS_REPLACE",
 167	"RTWS_DEF_FREE",
 168	"RTWS_EXP_SYNC",
 169	"RTWS_COND_GET",
 170	"RTWS_COND_SYNC",
 171	"RTWS_SYNC",
 172	"RTWS_STUTTER",
 173	"RTWS_STOPPING",
 174};
 175
 176static const char *rcu_torture_writer_state_getname(void)
 177{
 178	unsigned int i = READ_ONCE(rcu_torture_writer_state);
 179
 180	if (i >= ARRAY_SIZE(rcu_torture_writer_state_names))
 181		return "???";
 182	return rcu_torture_writer_state_names[i];
 183}
 184
 185static int torture_runnable = IS_ENABLED(MODULE);
 186module_param(torture_runnable, int, 0444);
 187MODULE_PARM_DESC(torture_runnable, "Start rcutorture at boot");
 188
 189#if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
 190#define rcu_can_boost() 1
 191#else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
 192#define rcu_can_boost() 0
 193#endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
 194
 195#ifdef CONFIG_RCU_TRACE
 196static u64 notrace rcu_trace_clock_local(void)
 197{
 198	u64 ts = trace_clock_local();
 199	unsigned long __maybe_unused ts_rem = do_div(ts, NSEC_PER_USEC);
 200	return ts;
 201}
 202#else /* #ifdef CONFIG_RCU_TRACE */
 203static u64 notrace rcu_trace_clock_local(void)
 204{
 205	return 0ULL;
 206}
 207#endif /* #else #ifdef CONFIG_RCU_TRACE */
 208
 209static unsigned long boost_starttime;	/* jiffies of next boost test start. */
 210static DEFINE_MUTEX(boost_mutex);	/* protect setting boost_starttime */
 211					/*  and boost task create/destroy. */
 212static atomic_t barrier_cbs_count;	/* Barrier callbacks registered. */
 213static bool barrier_phase;		/* Test phase. */
 214static atomic_t barrier_cbs_invoked;	/* Barrier callbacks invoked. */
 215static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
 216static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
 217
 218/*
 219 * Allocate an element from the rcu_tortures pool.
 220 */
 221static struct rcu_torture *
 222rcu_torture_alloc(void)
 223{
 224	struct list_head *p;
 225
 226	spin_lock_bh(&rcu_torture_lock);
 227	if (list_empty(&rcu_torture_freelist)) {
 228		atomic_inc(&n_rcu_torture_alloc_fail);
 229		spin_unlock_bh(&rcu_torture_lock);
 230		return NULL;
 231	}
 232	atomic_inc(&n_rcu_torture_alloc);
 233	p = rcu_torture_freelist.next;
 234	list_del_init(p);
 235	spin_unlock_bh(&rcu_torture_lock);
 236	return container_of(p, struct rcu_torture, rtort_free);
 237}
 238
 239/*
 240 * Free an element to the rcu_tortures pool.
 241 */
 242static void
 243rcu_torture_free(struct rcu_torture *p)
 244{
 245	atomic_inc(&n_rcu_torture_free);
 246	spin_lock_bh(&rcu_torture_lock);
 247	list_add_tail(&p->rtort_free, &rcu_torture_freelist);
 248	spin_unlock_bh(&rcu_torture_lock);
 249}
 250
 251/*
 252 * Operations vector for selecting different types of tests.
 253 */
 254
 255struct rcu_torture_ops {
 256	int ttype;
 257	void (*init)(void);
 258	void (*cleanup)(void);
 259	int (*readlock)(void);
 260	void (*read_delay)(struct torture_random_state *rrsp);
 261	void (*readunlock)(int idx);
 262	unsigned long (*started)(void);
 263	unsigned long (*completed)(void);
 264	void (*deferred_free)(struct rcu_torture *p);
 265	void (*sync)(void);
 266	void (*exp_sync)(void);
 267	unsigned long (*get_state)(void);
 268	void (*cond_sync)(unsigned long oldstate);
 269	call_rcu_func_t call;
 270	void (*cb_barrier)(void);
 271	void (*fqs)(void);
 272	void (*stats)(void);
 273	int irq_capable;
 274	int can_boost;
 275	const char *name;
 276};
 277
 278static struct rcu_torture_ops *cur_ops;
 279
 280/*
 281 * Definitions for rcu torture testing.
 282 */
 283
 284static int rcu_torture_read_lock(void) __acquires(RCU)
 285{
 286	rcu_read_lock();
 287	return 0;
 288}
 289
 290static void rcu_read_delay(struct torture_random_state *rrsp)
 291{
 292	unsigned long started;
 293	unsigned long completed;
 294	const unsigned long shortdelay_us = 200;
 295	const unsigned long longdelay_ms = 50;
 296	unsigned long long ts;
 297
 298	/* We want a short delay sometimes to make a reader delay the grace
 299	 * period, and we want a long delay occasionally to trigger
 300	 * force_quiescent_state. */
 301
 302	if (!(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) {
 303		started = cur_ops->completed();
 304		ts = rcu_trace_clock_local();
 305		mdelay(longdelay_ms);
 306		completed = cur_ops->completed();
 307		do_trace_rcu_torture_read(cur_ops->name, NULL, ts,
 308					  started, completed);
 309	}
 310	if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
 311		udelay(shortdelay_us);
 312#ifdef CONFIG_PREEMPT
 313	if (!preempt_count() &&
 314	    !(torture_random(rrsp) % (nrealreaders * 20000)))
 315		preempt_schedule();  /* No QS if preempt_disable() in effect */
 316#endif
 317}
 318
 319static 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 */
 327static bool
 328rcu_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 */
 347static void
 348rcu_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
 363static void
 364rcu_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
 379static unsigned long rcu_no_completed(void)
 380{
 381	return 0;
 382}
 383
 384static void rcu_torture_deferred_free(struct rcu_torture *p)
 385{
 386	call_rcu(&p->rtort_rcu, rcu_torture_cb);
 387}
 388
 389static void rcu_sync_torture_init(void)
 390{
 391	INIT_LIST_HEAD(&rcu_torture_removed);
 392}
 393
 394static 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
 420static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
 421{
 422	rcu_read_lock_bh();
 423	return 0;
 424}
 425
 426static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
 427{
 428	rcu_read_unlock_bh();
 429}
 430
 
 
 
 
 
 431static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
 432{
 433	call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
 434}
 435
 436static 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 */
 462static 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
 468static void synchronize_rcu_busted(void)
 469{
 470	/* This is a deliberate bug for testing purposes only! */
 471}
 472
 473static void
 474call_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
 480static 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		= "rcu_busted"
 497};
 498
 499/*
 500 * Definitions for srcu torture testing.
 501 */
 502
 503DEFINE_STATIC_SRCU(srcu_ctl);
 504static struct srcu_struct srcu_ctld;
 505static struct srcu_struct *srcu_ctlp = &srcu_ctl;
 506
 507static int srcu_torture_read_lock(void) __acquires(srcu_ctlp)
 508{
 509	return srcu_read_lock(srcu_ctlp);
 510}
 511
 512static 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)
 523		schedule_timeout_interruptible(longdelay);
 524	else
 525		rcu_read_delay(rrsp);
 526}
 527
 528static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp)
 529{
 530	srcu_read_unlock(srcu_ctlp, idx);
 531}
 532
 533static unsigned long srcu_torture_completed(void)
 534{
 535	return srcu_batches_completed(srcu_ctlp);
 536}
 537
 538static void srcu_torture_deferred_free(struct rcu_torture *rp)
 539{
 540	call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
 541}
 542
 543static void srcu_torture_synchronize(void)
 544{
 545	synchronize_srcu(srcu_ctlp);
 546}
 547
 548static void srcu_torture_call(struct rcu_head *head,
 549			      rcu_callback_t func)
 550{
 551	call_srcu(srcu_ctlp, head, func);
 552}
 553
 554static void srcu_torture_barrier(void)
 555{
 556	srcu_barrier(srcu_ctlp);
 557}
 558
 559static void srcu_torture_stats(void)
 560{
 561	int cpu;
 562	int idx = srcu_ctlp->completed & 0x1;
 563
 564	pr_alert("%s%s per-CPU(idx=%d):",
 565		 torture_type, TORTURE_FLAG, idx);
 566	for_each_possible_cpu(cpu) {
 567		long c0, c1;
 568
 569		c0 = (long)per_cpu_ptr(srcu_ctlp->per_cpu_ref, cpu)->c[!idx];
 570		c1 = (long)per_cpu_ptr(srcu_ctlp->per_cpu_ref, cpu)->c[idx];
 571		pr_cont(" %d(%ld,%ld)", cpu, c0, c1);
 572	}
 573	pr_cont("\n");
 574}
 575
 576static void srcu_torture_synchronize_expedited(void)
 577{
 578	synchronize_srcu_expedited(srcu_ctlp);
 579}
 580
 581static struct rcu_torture_ops srcu_ops = {
 582	.ttype		= SRCU_FLAVOR,
 583	.init		= rcu_sync_torture_init,
 584	.readlock	= srcu_torture_read_lock,
 585	.read_delay	= srcu_read_delay,
 586	.readunlock	= srcu_torture_read_unlock,
 587	.started	= NULL,
 588	.completed	= srcu_torture_completed,
 589	.deferred_free	= srcu_torture_deferred_free,
 590	.sync		= srcu_torture_synchronize,
 591	.exp_sync	= srcu_torture_synchronize_expedited,
 592	.call		= srcu_torture_call,
 593	.cb_barrier	= srcu_torture_barrier,
 594	.stats		= srcu_torture_stats,
 595	.name		= "srcu"
 596};
 597
 598static void srcu_torture_init(void)
 599{
 600	rcu_sync_torture_init();
 601	WARN_ON(init_srcu_struct(&srcu_ctld));
 602	srcu_ctlp = &srcu_ctld;
 603}
 604
 605static void srcu_torture_cleanup(void)
 606{
 607	cleanup_srcu_struct(&srcu_ctld);
 608	srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
 609}
 610
 611/* As above, but dynamically allocated. */
 612static struct rcu_torture_ops srcud_ops = {
 613	.ttype		= SRCU_FLAVOR,
 614	.init		= srcu_torture_init,
 615	.cleanup	= srcu_torture_cleanup,
 616	.readlock	= srcu_torture_read_lock,
 617	.read_delay	= srcu_read_delay,
 618	.readunlock	= srcu_torture_read_unlock,
 619	.started	= NULL,
 620	.completed	= srcu_torture_completed,
 621	.deferred_free	= srcu_torture_deferred_free,
 622	.sync		= srcu_torture_synchronize,
 623	.exp_sync	= srcu_torture_synchronize_expedited,
 624	.call		= srcu_torture_call,
 625	.cb_barrier	= srcu_torture_barrier,
 626	.stats		= srcu_torture_stats,
 627	.name		= "srcud"
 628};
 629
 630/*
 631 * Definitions for sched torture testing.
 632 */
 633
 634static int sched_torture_read_lock(void)
 635{
 636	preempt_disable();
 637	return 0;
 638}
 639
 640static void sched_torture_read_unlock(int idx)
 641{
 642	preempt_enable();
 643}
 644
 645static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
 646{
 647	call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
 648}
 649
 650static struct rcu_torture_ops sched_ops = {
 651	.ttype		= RCU_SCHED_FLAVOR,
 652	.init		= rcu_sync_torture_init,
 653	.readlock	= sched_torture_read_lock,
 654	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */
 655	.readunlock	= sched_torture_read_unlock,
 656	.started	= rcu_batches_started_sched,
 657	.completed	= rcu_batches_completed_sched,
 658	.deferred_free	= rcu_sched_torture_deferred_free,
 659	.sync		= synchronize_sched,
 660	.exp_sync	= synchronize_sched_expedited,
 661	.get_state	= get_state_synchronize_sched,
 662	.cond_sync	= cond_synchronize_sched,
 663	.call		= call_rcu_sched,
 664	.cb_barrier	= rcu_barrier_sched,
 665	.fqs		= rcu_sched_force_quiescent_state,
 666	.stats		= NULL,
 667	.irq_capable	= 1,
 668	.name		= "sched"
 669};
 670
 671#ifdef CONFIG_TASKS_RCU
 672
 673/*
 674 * Definitions for RCU-tasks torture testing.
 675 */
 676
 677static int tasks_torture_read_lock(void)
 678{
 679	return 0;
 680}
 681
 682static void tasks_torture_read_unlock(int idx)
 683{
 684}
 685
 686static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
 687{
 688	call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
 689}
 690
 691static struct rcu_torture_ops tasks_ops = {
 692	.ttype		= RCU_TASKS_FLAVOR,
 693	.init		= rcu_sync_torture_init,
 694	.readlock	= tasks_torture_read_lock,
 695	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */
 696	.readunlock	= tasks_torture_read_unlock,
 697	.started	= rcu_no_completed,
 698	.completed	= rcu_no_completed,
 699	.deferred_free	= rcu_tasks_torture_deferred_free,
 700	.sync		= synchronize_rcu_tasks,
 701	.exp_sync	= synchronize_rcu_tasks,
 702	.call		= call_rcu_tasks,
 703	.cb_barrier	= rcu_barrier_tasks,
 704	.fqs		= NULL,
 705	.stats		= NULL,
 706	.irq_capable	= 1,
 707	.name		= "tasks"
 708};
 709
 710#define RCUTORTURE_TASKS_OPS &tasks_ops,
 711
 712static bool __maybe_unused torturing_tasks(void)
 713{
 714	return cur_ops == &tasks_ops;
 715}
 716
 717#else /* #ifdef CONFIG_TASKS_RCU */
 718
 719#define RCUTORTURE_TASKS_OPS
 720
 721static bool __maybe_unused torturing_tasks(void)
 722{
 723	return false;
 724}
 725
 726#endif /* #else #ifdef CONFIG_TASKS_RCU */
 727
 728/*
 729 * RCU torture priority-boost testing.  Runs one real-time thread per
 730 * CPU for moderate bursts, repeatedly registering RCU callbacks and
 731 * spinning waiting for them to be invoked.  If a given callback takes
 732 * too long to be invoked, we assume that priority inversion has occurred.
 733 */
 734
 735struct rcu_boost_inflight {
 736	struct rcu_head rcu;
 737	int inflight;
 738};
 739
 740static void rcu_torture_boost_cb(struct rcu_head *head)
 741{
 742	struct rcu_boost_inflight *rbip =
 743		container_of(head, struct rcu_boost_inflight, rcu);
 744
 745	/* Ensure RCU-core accesses precede clearing ->inflight */
 746	smp_store_release(&rbip->inflight, 0);
 747}
 748
 749static int rcu_torture_boost(void *arg)
 750{
 751	unsigned long call_rcu_time;
 752	unsigned long endtime;
 753	unsigned long oldstarttime;
 754	struct rcu_boost_inflight rbi = { .inflight = 0 };
 755	struct sched_param sp;
 756
 757	VERBOSE_TOROUT_STRING("rcu_torture_boost started");
 758
 759	/* Set real-time priority. */
 760	sp.sched_priority = 1;
 761	if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
 762		VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!");
 763		n_rcu_torture_boost_rterror++;
 764	}
 765
 766	init_rcu_head_on_stack(&rbi.rcu);
 767	/* Each pass through the following loop does one boost-test cycle. */
 768	do {
 769		/* Wait for the next test interval. */
 770		oldstarttime = boost_starttime;
 771		while (ULONG_CMP_LT(jiffies, oldstarttime)) {
 772			schedule_timeout_interruptible(oldstarttime - jiffies);
 773			stutter_wait("rcu_torture_boost");
 774			if (torture_must_stop())
 775				goto checkwait;
 776		}
 777
 778		/* Do one boost-test interval. */
 779		endtime = oldstarttime + test_boost_duration * HZ;
 780		call_rcu_time = jiffies;
 781		while (ULONG_CMP_LT(jiffies, endtime)) {
 782			/* If we don't have a callback in flight, post one. */
 783			if (!smp_load_acquire(&rbi.inflight)) {
 784				/* RCU core before ->inflight = 1. */
 785				smp_store_release(&rbi.inflight, 1);
 786				call_rcu(&rbi.rcu, rcu_torture_boost_cb);
 787				if (jiffies - call_rcu_time >
 788					 test_boost_duration * HZ - HZ / 2) {
 789					VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
 790					n_rcu_torture_boost_failure++;
 791				}
 792				call_rcu_time = jiffies;
 793			}
 
 794			stutter_wait("rcu_torture_boost");
 795			if (torture_must_stop())
 796				goto checkwait;
 797		}
 798
 799		/*
 800		 * Set the start time of the next test interval.
 801		 * Yes, this is vulnerable to long delays, but such
 802		 * delays simply cause a false negative for the next
 803		 * interval.  Besides, we are running at RT priority,
 804		 * so delays should be relatively rare.
 805		 */
 806		while (oldstarttime == boost_starttime &&
 807		       !kthread_should_stop()) {
 808			if (mutex_trylock(&boost_mutex)) {
 809				boost_starttime = jiffies +
 810						  test_boost_interval * HZ;
 811				n_rcu_torture_boosts++;
 812				mutex_unlock(&boost_mutex);
 813				break;
 814			}
 815			schedule_timeout_uninterruptible(1);
 816		}
 817
 818		/* Go do the stutter. */
 819checkwait:	stutter_wait("rcu_torture_boost");
 820	} while (!torture_must_stop());
 821
 822	/* Clean up and exit. */
 823	while (!kthread_should_stop() || smp_load_acquire(&rbi.inflight)) {
 824		torture_shutdown_absorb("rcu_torture_boost");
 825		schedule_timeout_uninterruptible(1);
 826	}
 
 827	destroy_rcu_head_on_stack(&rbi.rcu);
 828	torture_kthread_stopping("rcu_torture_boost");
 829	return 0;
 830}
 831
 832static void rcu_torture_cbflood_cb(struct rcu_head *rhp)
 833{
 834}
 835
 836/*
 837 * RCU torture callback-flood kthread.  Repeatedly induces bursts of calls
 838 * to call_rcu() or analogous, increasing the probability of occurrence
 839 * of callback-overflow corner cases.
 840 */
 841static int
 842rcu_torture_cbflood(void *arg)
 843{
 844	int err = 1;
 845	int i;
 846	int j;
 847	struct rcu_head *rhp;
 848
 849	if (cbflood_n_per_burst > 0 &&
 850	    cbflood_inter_holdoff > 0 &&
 851	    cbflood_intra_holdoff > 0 &&
 852	    cur_ops->call &&
 853	    cur_ops->cb_barrier) {
 854		rhp = vmalloc(sizeof(*rhp) *
 855			      cbflood_n_burst * cbflood_n_per_burst);
 856		err = !rhp;
 857	}
 858	if (err) {
 859		VERBOSE_TOROUT_STRING("rcu_torture_cbflood disabled: Bad args or OOM");
 860		goto wait_for_stop;
 861	}
 862	VERBOSE_TOROUT_STRING("rcu_torture_cbflood task started");
 863	do {
 864		schedule_timeout_interruptible(cbflood_inter_holdoff);
 865		atomic_long_inc(&n_cbfloods);
 866		WARN_ON(signal_pending(current));
 867		for (i = 0; i < cbflood_n_burst; i++) {
 868			for (j = 0; j < cbflood_n_per_burst; j++) {
 869				cur_ops->call(&rhp[i * cbflood_n_per_burst + j],
 870					      rcu_torture_cbflood_cb);
 871			}
 872			schedule_timeout_interruptible(cbflood_intra_holdoff);
 873			WARN_ON(signal_pending(current));
 874		}
 875		cur_ops->cb_barrier();
 876		stutter_wait("rcu_torture_cbflood");
 877	} while (!torture_must_stop());
 878	vfree(rhp);
 879wait_for_stop:
 880	torture_kthread_stopping("rcu_torture_cbflood");
 881	return 0;
 882}
 883
 884/*
 885 * RCU torture force-quiescent-state kthread.  Repeatedly induces
 886 * bursts of calls to force_quiescent_state(), increasing the probability
 887 * of occurrence of some important types of race conditions.
 888 */
 889static int
 890rcu_torture_fqs(void *arg)
 891{
 892	unsigned long fqs_resume_time;
 893	int fqs_burst_remaining;
 894
 895	VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
 896	do {
 897		fqs_resume_time = jiffies + fqs_stutter * HZ;
 898		while (ULONG_CMP_LT(jiffies, fqs_resume_time) &&
 899		       !kthread_should_stop()) {
 900			schedule_timeout_interruptible(1);
 901		}
 902		fqs_burst_remaining = fqs_duration;
 903		while (fqs_burst_remaining > 0 &&
 904		       !kthread_should_stop()) {
 905			cur_ops->fqs();
 906			udelay(fqs_holdoff);
 907			fqs_burst_remaining -= fqs_holdoff;
 908		}
 909		stutter_wait("rcu_torture_fqs");
 910	} while (!torture_must_stop());
 911	torture_kthread_stopping("rcu_torture_fqs");
 912	return 0;
 913}
 914
 915/*
 916 * RCU torture writer kthread.  Repeatedly substitutes a new structure
 917 * for that pointed to by rcu_torture_current, freeing the old structure
 918 * after a series of grace periods (the "pipeline").
 919 */
 920static int
 921rcu_torture_writer(void *arg)
 922{
 923	bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
 924	int expediting = 0;
 925	unsigned long gp_snap;
 926	bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal;
 927	bool gp_sync1 = gp_sync;
 928	int i;
 929	struct rcu_torture *rp;
 
 930	struct rcu_torture *old_rp;
 931	static DEFINE_TORTURE_RANDOM(rand);
 932	int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC,
 933			   RTWS_COND_GET, RTWS_SYNC };
 934	int nsynctypes = 0;
 935
 936	VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
 937	if (!can_expedite) {
 938		pr_alert("%s" TORTURE_FLAG
 939			 " GP expediting controlled from boot/sysfs for %s,\n",
 940			 torture_type, cur_ops->name);
 941		pr_alert("%s" TORTURE_FLAG
 942			 " Disabled dynamic grace-period expediting.\n",
 943			 torture_type);
 944	}
 945
 946	/* Initialize synctype[] array.  If none set, take default. */
 947	if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync1)
 948		gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true;
 949	if (gp_cond1 && cur_ops->get_state && cur_ops->cond_sync)
 950		synctype[nsynctypes++] = RTWS_COND_GET;
 951	else if (gp_cond && (!cur_ops->get_state || !cur_ops->cond_sync))
 952		pr_alert("rcu_torture_writer: gp_cond without primitives.\n");
 953	if (gp_exp1 && cur_ops->exp_sync)
 954		synctype[nsynctypes++] = RTWS_EXP_SYNC;
 955	else if (gp_exp && !cur_ops->exp_sync)
 956		pr_alert("rcu_torture_writer: gp_exp without primitives.\n");
 957	if (gp_normal1 && cur_ops->deferred_free)
 958		synctype[nsynctypes++] = RTWS_DEF_FREE;
 959	else if (gp_normal && !cur_ops->deferred_free)
 960		pr_alert("rcu_torture_writer: gp_normal without primitives.\n");
 961	if (gp_sync1 && cur_ops->sync)
 962		synctype[nsynctypes++] = RTWS_SYNC;
 963	else if (gp_sync && !cur_ops->sync)
 964		pr_alert("rcu_torture_writer: gp_sync without primitives.\n");
 965	if (WARN_ONCE(nsynctypes == 0,
 966		      "rcu_torture_writer: No update-side primitives.\n")) {
 967		/*
 968		 * No updates primitives, so don't try updating.
 969		 * The resulting test won't be testing much, hence the
 970		 * above WARN_ONCE().
 971		 */
 972		rcu_torture_writer_state = RTWS_STOPPING;
 973		torture_kthread_stopping("rcu_torture_writer");
 974	}
 975
 976	do {
 977		rcu_torture_writer_state = RTWS_FIXED_DELAY;
 978		schedule_timeout_uninterruptible(1);
 979		rp = rcu_torture_alloc();
 980		if (rp == NULL)
 981			continue;
 982		rp->rtort_pipe_count = 0;
 983		rcu_torture_writer_state = RTWS_DELAY;
 984		udelay(torture_random(&rand) & 0x3ff);
 985		rcu_torture_writer_state = RTWS_REPLACE;
 986		old_rp = rcu_dereference_check(rcu_torture_current,
 987					       current == writer_task);
 988		rp->rtort_mbtest = 1;
 989		rcu_assign_pointer(rcu_torture_current, rp);
 990		smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
 991		if (old_rp) {
 992			i = old_rp->rtort_pipe_count;
 993			if (i > RCU_TORTURE_PIPE_LEN)
 994				i = RCU_TORTURE_PIPE_LEN;
 995			atomic_inc(&rcu_torture_wcount[i]);
 996			old_rp->rtort_pipe_count++;
 997			switch (synctype[torture_random(&rand) % nsynctypes]) {
 998			case RTWS_DEF_FREE:
 999				rcu_torture_writer_state = RTWS_DEF_FREE;
 
 
1000				cur_ops->deferred_free(old_rp);
1001				break;
1002			case RTWS_EXP_SYNC:
1003				rcu_torture_writer_state = RTWS_EXP_SYNC;
1004				cur_ops->exp_sync();
1005				rcu_torture_pipe_update(old_rp);
1006				break;
1007			case RTWS_COND_GET:
1008				rcu_torture_writer_state = RTWS_COND_GET;
1009				gp_snap = cur_ops->get_state();
1010				i = torture_random(&rand) % 16;
1011				if (i != 0)
1012					schedule_timeout_interruptible(i);
1013				udelay(torture_random(&rand) % 1000);
1014				rcu_torture_writer_state = RTWS_COND_SYNC;
1015				cur_ops->cond_sync(gp_snap);
1016				rcu_torture_pipe_update(old_rp);
1017				break;
1018			case RTWS_SYNC:
1019				rcu_torture_writer_state = RTWS_SYNC;
1020				cur_ops->sync();
1021				rcu_torture_pipe_update(old_rp);
1022				break;
1023			default:
1024				WARN_ON_ONCE(1);
1025				break;
1026			}
1027		}
1028		rcutorture_record_progress(++rcu_torture_current_version);
1029		/* Cycle through nesting levels of rcu_expedite_gp() calls. */
1030		if (can_expedite &&
1031		    !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
1032			WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
1033			if (expediting >= 0)
1034				rcu_expedite_gp();
1035			else
1036				rcu_unexpedite_gp();
1037			if (++expediting > 3)
1038				expediting = -expediting;
1039		}
1040		rcu_torture_writer_state = RTWS_STUTTER;
1041		stutter_wait("rcu_torture_writer");
1042	} while (!torture_must_stop());
1043	/* Reset expediting back to unexpedited. */
1044	if (expediting > 0)
1045		expediting = -expediting;
1046	while (can_expedite && expediting++ < 0)
1047		rcu_unexpedite_gp();
1048	WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
1049	rcu_torture_writer_state = RTWS_STOPPING;
1050	torture_kthread_stopping("rcu_torture_writer");
1051	return 0;
1052}
1053
1054/*
1055 * RCU torture fake writer kthread.  Repeatedly calls sync, with a random
1056 * delay between calls.
1057 */
1058static int
1059rcu_torture_fakewriter(void *arg)
1060{
1061	DEFINE_TORTURE_RANDOM(rand);
1062
1063	VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1064	set_user_nice(current, MAX_NICE);
1065
1066	do {
1067		schedule_timeout_uninterruptible(1 + torture_random(&rand)%10);
1068		udelay(torture_random(&rand) & 0x3ff);
1069		if (cur_ops->cb_barrier != NULL &&
1070		    torture_random(&rand) % (nfakewriters * 8) == 0) {
1071			cur_ops->cb_barrier();
1072		} else if (gp_normal == gp_exp) {
1073			if (torture_random(&rand) & 0x80)
1074				cur_ops->sync();
1075			else
1076				cur_ops->exp_sync();
1077		} else if (gp_normal) {
1078			cur_ops->sync();
1079		} else {
1080			cur_ops->exp_sync();
1081		}
1082		stutter_wait("rcu_torture_fakewriter");
1083	} while (!torture_must_stop());
1084
1085	torture_kthread_stopping("rcu_torture_fakewriter");
1086	return 0;
1087}
1088
 
 
 
 
 
 
 
 
 
 
 
1089/*
1090 * RCU torture reader from timer handler.  Dereferences rcu_torture_current,
1091 * incrementing the corresponding element of the pipeline array.  The
1092 * counter in the element should never be greater than 1, otherwise, the
1093 * RCU implementation is broken.
1094 */
1095static void rcu_torture_timer(unsigned long unused)
1096{
1097	int idx;
1098	unsigned long started;
1099	unsigned long completed;
1100	static DEFINE_TORTURE_RANDOM(rand);
1101	static DEFINE_SPINLOCK(rand_lock);
1102	struct rcu_torture *p;
1103	int pipe_count;
1104	unsigned long long ts;
1105
1106	idx = cur_ops->readlock();
1107	if (cur_ops->started)
1108		started = cur_ops->started();
1109	else
1110		started = cur_ops->completed();
1111	ts = rcu_trace_clock_local();
1112	p = rcu_dereference_check(rcu_torture_current,
1113				  rcu_read_lock_bh_held() ||
1114				  rcu_read_lock_sched_held() ||
1115				  srcu_read_lock_held(srcu_ctlp) ||
1116				  torturing_tasks());
1117	if (p == NULL) {
1118		/* Leave because rcu_torture_writer is not yet underway */
1119		cur_ops->readunlock(idx);
1120		return;
1121	}
1122	if (p->rtort_mbtest == 0)
1123		atomic_inc(&n_rcu_torture_mberror);
1124	spin_lock(&rand_lock);
1125	cur_ops->read_delay(&rand);
1126	n_rcu_torture_timers++;
1127	spin_unlock(&rand_lock);
1128	preempt_disable();
1129	pipe_count = p->rtort_pipe_count;
1130	if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1131		/* Should not happen, but... */
1132		pipe_count = RCU_TORTURE_PIPE_LEN;
1133	}
1134	completed = cur_ops->completed();
1135	if (pipe_count > 1) {
1136		do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, ts,
1137					  started, completed);
1138		rcu_ftrace_dump(DUMP_ALL);
1139	}
1140	__this_cpu_inc(rcu_torture_count[pipe_count]);
1141	completed = completed - started;
1142	if (cur_ops->started)
1143		completed++;
1144	if (completed > RCU_TORTURE_PIPE_LEN) {
1145		/* Should not happen, but... */
1146		completed = RCU_TORTURE_PIPE_LEN;
1147	}
1148	__this_cpu_inc(rcu_torture_batch[completed]);
1149	preempt_enable();
1150	cur_ops->readunlock(idx);
1151}
1152
1153/*
1154 * RCU torture reader kthread.  Repeatedly dereferences rcu_torture_current,
1155 * incrementing the corresponding element of the pipeline array.  The
1156 * counter in the element should never be greater than 1, otherwise, the
1157 * RCU implementation is broken.
1158 */
1159static int
1160rcu_torture_reader(void *arg)
1161{
1162	unsigned long started;
1163	unsigned long completed;
1164	int idx;
1165	DEFINE_TORTURE_RANDOM(rand);
1166	struct rcu_torture *p;
1167	int pipe_count;
1168	struct timer_list t;
1169	unsigned long long ts;
1170
1171	VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
1172	set_user_nice(current, MAX_NICE);
1173	if (irqreader && cur_ops->irq_capable)
1174		setup_timer_on_stack(&t, rcu_torture_timer, 0);
1175
1176	do {
1177		if (irqreader && cur_ops->irq_capable) {
1178			if (!timer_pending(&t))
1179				mod_timer(&t, jiffies + 1);
1180		}
1181		idx = cur_ops->readlock();
1182		if (cur_ops->started)
1183			started = cur_ops->started();
1184		else
1185			started = cur_ops->completed();
1186		ts = rcu_trace_clock_local();
1187		p = rcu_dereference_check(rcu_torture_current,
1188					  rcu_read_lock_bh_held() ||
1189					  rcu_read_lock_sched_held() ||
1190					  srcu_read_lock_held(srcu_ctlp) ||
1191					  torturing_tasks());
1192		if (p == NULL) {
1193			/* Wait for rcu_torture_writer to get underway */
1194			cur_ops->readunlock(idx);
1195			schedule_timeout_interruptible(HZ);
1196			continue;
1197		}
1198		if (p->rtort_mbtest == 0)
1199			atomic_inc(&n_rcu_torture_mberror);
1200		cur_ops->read_delay(&rand);
1201		preempt_disable();
1202		pipe_count = p->rtort_pipe_count;
1203		if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1204			/* Should not happen, but... */
1205			pipe_count = RCU_TORTURE_PIPE_LEN;
1206		}
1207		completed = cur_ops->completed();
1208		if (pipe_count > 1) {
1209			do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
1210						  ts, started, completed);
1211			rcu_ftrace_dump(DUMP_ALL);
1212		}
1213		__this_cpu_inc(rcu_torture_count[pipe_count]);
1214		completed = completed - started;
1215		if (cur_ops->started)
1216			completed++;
1217		if (completed > RCU_TORTURE_PIPE_LEN) {
1218			/* Should not happen, but... */
1219			completed = RCU_TORTURE_PIPE_LEN;
1220		}
1221		__this_cpu_inc(rcu_torture_batch[completed]);
1222		preempt_enable();
1223		cur_ops->readunlock(idx);
 
1224		stutter_wait("rcu_torture_reader");
1225	} while (!torture_must_stop());
1226	if (irqreader && cur_ops->irq_capable) {
1227		del_timer_sync(&t);
1228		destroy_timer_on_stack(&t);
1229	}
1230	torture_kthread_stopping("rcu_torture_reader");
1231	return 0;
1232}
1233
1234/*
1235 * Print torture statistics.  Caller must ensure that there is only
1236 * one call to this function at a given time!!!  This is normally
1237 * accomplished by relying on the module system to only have one copy
1238 * of the module loaded, and then by giving the rcu_torture_stats
1239 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1240 * thread is not running).
1241 */
1242static void
1243rcu_torture_stats_print(void)
1244{
1245	int cpu;
1246	int i;
1247	long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1248	long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1249	static unsigned long rtcv_snap = ULONG_MAX;
1250	struct task_struct *wtp;
1251
1252	for_each_possible_cpu(cpu) {
1253		for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1254			pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
1255			batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
1256		}
1257	}
1258	for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
1259		if (pipesummary[i] != 0)
1260			break;
1261	}
1262
1263	pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1264	pr_cont("rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
1265		rcu_torture_current,
1266		rcu_torture_current_version,
1267		list_empty(&rcu_torture_freelist),
1268		atomic_read(&n_rcu_torture_alloc),
1269		atomic_read(&n_rcu_torture_alloc_fail),
1270		atomic_read(&n_rcu_torture_free));
1271	pr_cont("rtmbe: %d rtbe: %ld rtbke: %ld rtbre: %ld ",
1272		atomic_read(&n_rcu_torture_mberror),
1273		n_rcu_torture_barrier_error,
1274		n_rcu_torture_boost_ktrerror,
1275		n_rcu_torture_boost_rterror);
1276	pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
1277		n_rcu_torture_boost_failure,
1278		n_rcu_torture_boosts,
1279		n_rcu_torture_timers);
1280	torture_onoff_stats();
1281	pr_cont("barrier: %ld/%ld:%ld ",
1282		n_barrier_successes,
1283		n_barrier_attempts,
1284		n_rcu_torture_barrier_error);
1285	pr_cont("cbflood: %ld\n", atomic_long_read(&n_cbfloods));
1286
1287	pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1288	if (atomic_read(&n_rcu_torture_mberror) != 0 ||
1289	    n_rcu_torture_barrier_error != 0 ||
1290	    n_rcu_torture_boost_ktrerror != 0 ||
1291	    n_rcu_torture_boost_rterror != 0 ||
1292	    n_rcu_torture_boost_failure != 0 ||
1293	    i > 1) {
1294		pr_cont("%s", "!!! ");
1295		atomic_inc(&n_rcu_torture_error);
1296		WARN_ON_ONCE(1);
1297	}
1298	pr_cont("Reader Pipe: ");
1299	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1300		pr_cont(" %ld", pipesummary[i]);
1301	pr_cont("\n");
1302
1303	pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1304	pr_cont("Reader Batch: ");
1305	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1306		pr_cont(" %ld", batchsummary[i]);
1307	pr_cont("\n");
1308
1309	pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1310	pr_cont("Free-Block Circulation: ");
1311	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1312		pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
 
1313	}
1314	pr_cont("\n");
1315
1316	if (cur_ops->stats)
1317		cur_ops->stats();
1318	if (rtcv_snap == rcu_torture_current_version &&
1319	    rcu_torture_current != NULL) {
1320		int __maybe_unused flags;
1321		unsigned long __maybe_unused gpnum;
1322		unsigned long __maybe_unused completed;
1323
1324		rcutorture_get_gp_data(cur_ops->ttype,
1325				       &flags, &gpnum, &completed);
1326		wtp = READ_ONCE(writer_task);
1327		pr_alert("??? Writer stall state %s(%d) g%lu c%lu f%#x ->state %#lx\n",
1328			 rcu_torture_writer_state_getname(),
1329			 rcu_torture_writer_state,
1330			 gpnum, completed, flags,
1331			 wtp == NULL ? ~0UL : wtp->state);
1332		show_rcu_gp_kthreads();
1333		rcu_ftrace_dump(DUMP_ALL);
 
 
 
 
1334	}
1335	rtcv_snap = rcu_torture_current_version;
 
 
1336}
1337
1338/*
1339 * Periodically prints torture statistics, if periodic statistics printing
1340 * was specified via the stat_interval module parameter.
1341 */
1342static int
1343rcu_torture_stats(void *arg)
1344{
1345	VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1346	do {
1347		schedule_timeout_interruptible(stat_interval * HZ);
1348		rcu_torture_stats_print();
1349		torture_shutdown_absorb("rcu_torture_stats");
1350	} while (!torture_must_stop());
1351	torture_kthread_stopping("rcu_torture_stats");
1352	return 0;
1353}
1354
1355static inline void
1356rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1357{
1358	pr_alert("%s" TORTURE_FLAG
1359		 "--- %s: nreaders=%d nfakewriters=%d "
1360		 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1361		 "shuffle_interval=%d stutter=%d irqreader=%d "
1362		 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1363		 "test_boost=%d/%d test_boost_interval=%d "
1364		 "test_boost_duration=%d shutdown_secs=%d "
1365		 "stall_cpu=%d stall_cpu_holdoff=%d "
1366		 "n_barrier_cbs=%d "
1367		 "onoff_interval=%d onoff_holdoff=%d\n",
1368		 torture_type, tag, nrealreaders, nfakewriters,
1369		 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1370		 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1371		 test_boost, cur_ops->can_boost,
1372		 test_boost_interval, test_boost_duration, shutdown_secs,
1373		 stall_cpu, stall_cpu_holdoff,
1374		 n_barrier_cbs,
1375		 onoff_interval, onoff_holdoff);
1376}
1377
1378static int rcutorture_booster_cleanup(unsigned int cpu)
1379{
1380	struct task_struct *t;
1381
1382	if (boost_tasks[cpu] == NULL)
1383		return 0;
1384	mutex_lock(&boost_mutex);
1385	t = boost_tasks[cpu];
1386	boost_tasks[cpu] = NULL;
1387	mutex_unlock(&boost_mutex);
1388
1389	/* This must be outside of the mutex, otherwise deadlock! */
1390	torture_stop_kthread(rcu_torture_boost, t);
1391	return 0;
1392}
1393
1394static int rcutorture_booster_init(unsigned int cpu)
1395{
1396	int retval;
1397
1398	if (boost_tasks[cpu] != NULL)
1399		return 0;  /* Already created, nothing more to do. */
1400
1401	/* Don't allow time recalculation while creating a new task. */
1402	mutex_lock(&boost_mutex);
1403	VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
1404	boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
1405						  cpu_to_node(cpu),
1406						  "rcu_torture_boost");
1407	if (IS_ERR(boost_tasks[cpu])) {
1408		retval = PTR_ERR(boost_tasks[cpu]);
1409		VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
1410		n_rcu_torture_boost_ktrerror++;
1411		boost_tasks[cpu] = NULL;
1412		mutex_unlock(&boost_mutex);
1413		return retval;
1414	}
1415	kthread_bind(boost_tasks[cpu], cpu);
1416	wake_up_process(boost_tasks[cpu]);
1417	mutex_unlock(&boost_mutex);
1418	return 0;
1419}
1420
1421/*
1422 * CPU-stall kthread.  It waits as specified by stall_cpu_holdoff, then
1423 * induces a CPU stall for the time specified by stall_cpu.
1424 */
1425static int rcu_torture_stall(void *args)
1426{
1427	unsigned long stop_at;
1428
1429	VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
1430	if (stall_cpu_holdoff > 0) {
1431		VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
1432		schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
1433		VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
1434	}
1435	if (!kthread_should_stop()) {
1436		stop_at = get_seconds() + stall_cpu;
1437		/* RCU CPU stall is expected behavior in following code. */
1438		pr_alert("rcu_torture_stall start.\n");
1439		rcu_read_lock();
1440		preempt_disable();
1441		while (ULONG_CMP_LT(get_seconds(), stop_at))
1442			continue;  /* Induce RCU CPU stall warning. */
1443		preempt_enable();
1444		rcu_read_unlock();
1445		pr_alert("rcu_torture_stall end.\n");
1446	}
1447	torture_shutdown_absorb("rcu_torture_stall");
1448	while (!kthread_should_stop())
1449		schedule_timeout_interruptible(10 * HZ);
1450	return 0;
1451}
1452
1453/* Spawn CPU-stall kthread, if stall_cpu specified. */
1454static int __init rcu_torture_stall_init(void)
1455{
1456	if (stall_cpu <= 0)
1457		return 0;
1458	return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
1459}
1460
1461/* Callback function for RCU barrier testing. */
1462static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
1463{
1464	atomic_inc(&barrier_cbs_invoked);
1465}
1466
1467/* kthread function to register callbacks used to test RCU barriers. */
1468static int rcu_torture_barrier_cbs(void *arg)
1469{
1470	long myid = (long)arg;
1471	bool lastphase = 0;
1472	bool newphase;
1473	struct rcu_head rcu;
1474
1475	init_rcu_head_on_stack(&rcu);
1476	VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
1477	set_user_nice(current, MAX_NICE);
1478	do {
1479		wait_event(barrier_cbs_wq[myid],
1480			   (newphase =
1481			    smp_load_acquire(&barrier_phase)) != lastphase ||
1482			   torture_must_stop());
1483		lastphase = newphase;
 
1484		if (torture_must_stop())
1485			break;
1486		/*
1487		 * The above smp_load_acquire() ensures barrier_phase load
1488		 * is ordered before the following ->call().
1489		 */
1490		local_irq_disable(); /* Just to test no-irq call_rcu(). */
1491		cur_ops->call(&rcu, rcu_torture_barrier_cbf);
1492		local_irq_enable();
1493		if (atomic_dec_and_test(&barrier_cbs_count))
1494			wake_up(&barrier_wq);
1495	} while (!torture_must_stop());
1496	if (cur_ops->cb_barrier != NULL)
1497		cur_ops->cb_barrier();
1498	destroy_rcu_head_on_stack(&rcu);
1499	torture_kthread_stopping("rcu_torture_barrier_cbs");
1500	return 0;
1501}
1502
1503/* kthread function to drive and coordinate RCU barrier testing. */
1504static int rcu_torture_barrier(void *arg)
1505{
1506	int i;
1507
1508	VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
1509	do {
1510		atomic_set(&barrier_cbs_invoked, 0);
1511		atomic_set(&barrier_cbs_count, n_barrier_cbs);
1512		/* Ensure barrier_phase ordered after prior assignments. */
1513		smp_store_release(&barrier_phase, !barrier_phase);
1514		for (i = 0; i < n_barrier_cbs; i++)
1515			wake_up(&barrier_cbs_wq[i]);
1516		wait_event(barrier_wq,
1517			   atomic_read(&barrier_cbs_count) == 0 ||
1518			   torture_must_stop());
1519		if (torture_must_stop())
1520			break;
1521		n_barrier_attempts++;
1522		cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
1523		if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
1524			n_rcu_torture_barrier_error++;
1525			pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
1526			       atomic_read(&barrier_cbs_invoked),
1527			       n_barrier_cbs);
1528			WARN_ON_ONCE(1);
1529		}
1530		n_barrier_successes++;
1531		schedule_timeout_interruptible(HZ / 10);
1532	} while (!torture_must_stop());
1533	torture_kthread_stopping("rcu_torture_barrier");
1534	return 0;
1535}
1536
1537/* Initialize RCU barrier testing. */
1538static int rcu_torture_barrier_init(void)
1539{
1540	int i;
1541	int ret;
1542
1543	if (n_barrier_cbs <= 0)
1544		return 0;
1545	if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
1546		pr_alert("%s" TORTURE_FLAG
1547			 " Call or barrier ops missing for %s,\n",
1548			 torture_type, cur_ops->name);
1549		pr_alert("%s" TORTURE_FLAG
1550			 " RCU barrier testing omitted from run.\n",
1551			 torture_type);
1552		return 0;
1553	}
1554	atomic_set(&barrier_cbs_count, 0);
1555	atomic_set(&barrier_cbs_invoked, 0);
1556	barrier_cbs_tasks =
1557		kzalloc(n_barrier_cbs * sizeof(barrier_cbs_tasks[0]),
1558			GFP_KERNEL);
1559	barrier_cbs_wq =
1560		kzalloc(n_barrier_cbs * sizeof(barrier_cbs_wq[0]),
1561			GFP_KERNEL);
1562	if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
1563		return -ENOMEM;
1564	for (i = 0; i < n_barrier_cbs; i++) {
1565		init_waitqueue_head(&barrier_cbs_wq[i]);
1566		ret = torture_create_kthread(rcu_torture_barrier_cbs,
1567					     (void *)(long)i,
1568					     barrier_cbs_tasks[i]);
1569		if (ret)
1570			return ret;
1571	}
1572	return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
1573}
1574
1575/* Clean up after RCU barrier testing. */
1576static void rcu_torture_barrier_cleanup(void)
1577{
1578	int i;
1579
1580	torture_stop_kthread(rcu_torture_barrier, barrier_task);
1581	if (barrier_cbs_tasks != NULL) {
1582		for (i = 0; i < n_barrier_cbs; i++)
1583			torture_stop_kthread(rcu_torture_barrier_cbs,
1584					     barrier_cbs_tasks[i]);
1585		kfree(barrier_cbs_tasks);
1586		barrier_cbs_tasks = NULL;
1587	}
1588	if (barrier_cbs_wq != NULL) {
1589		kfree(barrier_cbs_wq);
1590		barrier_cbs_wq = NULL;
1591	}
1592}
1593
1594static enum cpuhp_state rcutor_hp;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1595
1596static void
1597rcu_torture_cleanup(void)
1598{
1599	int i;
1600
1601	rcutorture_record_test_transition();
1602	if (torture_cleanup_begin()) {
1603		if (cur_ops->cb_barrier != NULL)
1604			cur_ops->cb_barrier();
1605		return;
1606	}
1607
1608	rcu_torture_barrier_cleanup();
1609	torture_stop_kthread(rcu_torture_stall, stall_task);
1610	torture_stop_kthread(rcu_torture_writer, writer_task);
1611
1612	if (reader_tasks) {
1613		for (i = 0; i < nrealreaders; i++)
1614			torture_stop_kthread(rcu_torture_reader,
1615					     reader_tasks[i]);
1616		kfree(reader_tasks);
1617	}
1618	rcu_torture_current = NULL;
1619
1620	if (fakewriter_tasks) {
1621		for (i = 0; i < nfakewriters; i++) {
1622			torture_stop_kthread(rcu_torture_fakewriter,
1623					     fakewriter_tasks[i]);
1624		}
1625		kfree(fakewriter_tasks);
1626		fakewriter_tasks = NULL;
1627	}
1628
1629	torture_stop_kthread(rcu_torture_stats, stats_task);
1630	torture_stop_kthread(rcu_torture_fqs, fqs_task);
1631	for (i = 0; i < ncbflooders; i++)
1632		torture_stop_kthread(rcu_torture_cbflood, cbflood_task[i]);
1633	if ((test_boost == 1 && cur_ops->can_boost) ||
1634	    test_boost == 2)
1635		cpuhp_remove_state(rcutor_hp);
 
 
 
 
 
1636
1637	/*
1638	 * Wait for all RCU callbacks to fire, then do flavor-specific
1639	 * cleanup operations.
1640	 */
1641	if (cur_ops->cb_barrier != NULL)
1642		cur_ops->cb_barrier();
1643	if (cur_ops->cleanup != NULL)
1644		cur_ops->cleanup();
1645
1646	rcu_torture_stats_print();  /* -After- the stats thread is stopped! */
1647
1648	if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
1649		rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
1650	else if (torture_onoff_failures())
1651		rcu_torture_print_module_parms(cur_ops,
1652					       "End of test: RCU_HOTPLUG");
1653	else
1654		rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
1655	torture_cleanup_end();
1656}
1657
1658#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1659static void rcu_torture_leak_cb(struct rcu_head *rhp)
1660{
1661}
1662
1663static void rcu_torture_err_cb(struct rcu_head *rhp)
1664{
1665	/*
1666	 * This -might- happen due to race conditions, but is unlikely.
1667	 * The scenario that leads to this happening is that the
1668	 * first of the pair of duplicate callbacks is queued,
1669	 * someone else starts a grace period that includes that
1670	 * callback, then the second of the pair must wait for the
1671	 * next grace period.  Unlikely, but can happen.  If it
1672	 * does happen, the debug-objects subsystem won't have splatted.
1673	 */
1674	pr_alert("rcutorture: duplicated callback was invoked.\n");
1675}
1676#endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1677
1678/*
1679 * Verify that double-free causes debug-objects to complain, but only
1680 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y.  Otherwise, say that the test
1681 * cannot be carried out.
1682 */
1683static void rcu_test_debug_objects(void)
1684{
1685#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
1686	struct rcu_head rh1;
1687	struct rcu_head rh2;
1688
1689	init_rcu_head_on_stack(&rh1);
1690	init_rcu_head_on_stack(&rh2);
1691	pr_alert("rcutorture: WARN: Duplicate call_rcu() test starting.\n");
1692
1693	/* Try to queue the rh2 pair of callbacks for the same grace period. */
1694	preempt_disable(); /* Prevent preemption from interrupting test. */
1695	rcu_read_lock(); /* Make it impossible to finish a grace period. */
1696	call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
1697	local_irq_disable(); /* Make it harder to start a new grace period. */
1698	call_rcu(&rh2, rcu_torture_leak_cb);
1699	call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
1700	local_irq_enable();
1701	rcu_read_unlock();
1702	preempt_enable();
1703
1704	/* Wait for them all to get done so we can safely return. */
1705	rcu_barrier();
1706	pr_alert("rcutorture: WARN: Duplicate call_rcu() test complete.\n");
1707	destroy_rcu_head_on_stack(&rh1);
1708	destroy_rcu_head_on_stack(&rh2);
1709#else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1710	pr_alert("rcutorture: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n");
1711#endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
1712}
1713
1714static int __init
1715rcu_torture_init(void)
1716{
1717	int i;
1718	int cpu;
1719	int firsterr = 0;
1720	static struct rcu_torture_ops *torture_ops[] = {
1721		&rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops,
1722		&sched_ops, RCUTORTURE_TASKS_OPS
1723	};
1724
1725	if (!torture_init_begin(torture_type, verbose, &torture_runnable))
1726		return -EBUSY;
1727
1728	/* Process args and tell the world that the torturer is on the job. */
1729	for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1730		cur_ops = torture_ops[i];
1731		if (strcmp(torture_type, cur_ops->name) == 0)
1732			break;
1733	}
1734	if (i == ARRAY_SIZE(torture_ops)) {
1735		pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
1736			 torture_type);
1737		pr_alert("rcu-torture types:");
1738		for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1739			pr_alert(" %s", torture_ops[i]->name);
1740		pr_alert("\n");
1741		firsterr = -EINVAL;
1742		goto unwind;
1743	}
1744	if (cur_ops->fqs == NULL && fqs_duration != 0) {
1745		pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
1746		fqs_duration = 0;
1747	}
1748	if (cur_ops->init)
1749		cur_ops->init();
1750
1751	if (nreaders >= 0) {
1752		nrealreaders = nreaders;
1753	} else {
1754		nrealreaders = num_online_cpus() - 2 - nreaders;
1755		if (nrealreaders <= 0)
1756			nrealreaders = 1;
1757	}
1758	rcu_torture_print_module_parms(cur_ops, "Start of test");
1759
1760	/* Set up the freelist. */
1761
1762	INIT_LIST_HEAD(&rcu_torture_freelist);
1763	for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1764		rcu_tortures[i].rtort_mbtest = 0;
1765		list_add_tail(&rcu_tortures[i].rtort_free,
1766			      &rcu_torture_freelist);
1767	}
1768
1769	/* Initialize the statistics so that each run gets its own numbers. */
1770
1771	rcu_torture_current = NULL;
1772	rcu_torture_current_version = 0;
1773	atomic_set(&n_rcu_torture_alloc, 0);
1774	atomic_set(&n_rcu_torture_alloc_fail, 0);
1775	atomic_set(&n_rcu_torture_free, 0);
1776	atomic_set(&n_rcu_torture_mberror, 0);
1777	atomic_set(&n_rcu_torture_error, 0);
1778	n_rcu_torture_barrier_error = 0;
1779	n_rcu_torture_boost_ktrerror = 0;
1780	n_rcu_torture_boost_rterror = 0;
1781	n_rcu_torture_boost_failure = 0;
1782	n_rcu_torture_boosts = 0;
1783	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1784		atomic_set(&rcu_torture_wcount[i], 0);
1785	for_each_possible_cpu(cpu) {
1786		for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1787			per_cpu(rcu_torture_count, cpu)[i] = 0;
1788			per_cpu(rcu_torture_batch, cpu)[i] = 0;
1789		}
1790	}
1791
1792	/* Start up the kthreads. */
1793
1794	firsterr = torture_create_kthread(rcu_torture_writer, NULL,
1795					  writer_task);
1796	if (firsterr)
1797		goto unwind;
1798	if (nfakewriters > 0) {
1799		fakewriter_tasks = kzalloc(nfakewriters *
1800					   sizeof(fakewriter_tasks[0]),
1801					   GFP_KERNEL);
1802		if (fakewriter_tasks == NULL) {
1803			VERBOSE_TOROUT_ERRSTRING("out of memory");
1804			firsterr = -ENOMEM;
1805			goto unwind;
1806		}
1807	}
1808	for (i = 0; i < nfakewriters; i++) {
1809		firsterr = torture_create_kthread(rcu_torture_fakewriter,
1810						  NULL, fakewriter_tasks[i]);
1811		if (firsterr)
1812			goto unwind;
1813	}
1814	reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
1815			       GFP_KERNEL);
1816	if (reader_tasks == NULL) {
1817		VERBOSE_TOROUT_ERRSTRING("out of memory");
1818		firsterr = -ENOMEM;
1819		goto unwind;
1820	}
1821	for (i = 0; i < nrealreaders; i++) {
1822		firsterr = torture_create_kthread(rcu_torture_reader, NULL,
1823						  reader_tasks[i]);
1824		if (firsterr)
1825			goto unwind;
1826	}
1827	if (stat_interval > 0) {
1828		firsterr = torture_create_kthread(rcu_torture_stats, NULL,
1829						  stats_task);
1830		if (firsterr)
1831			goto unwind;
1832	}
1833	if (test_no_idle_hz && shuffle_interval > 0) {
1834		firsterr = torture_shuffle_init(shuffle_interval * HZ);
1835		if (firsterr)
1836			goto unwind;
1837	}
1838	if (stutter < 0)
1839		stutter = 0;
1840	if (stutter) {
1841		firsterr = torture_stutter_init(stutter * HZ);
1842		if (firsterr)
1843			goto unwind;
1844	}
1845	if (fqs_duration < 0)
1846		fqs_duration = 0;
1847	if (fqs_duration) {
1848		/* Create the fqs thread */
1849		firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
1850						  fqs_task);
1851		if (firsterr)
1852			goto unwind;
1853	}
1854	if (test_boost_interval < 1)
1855		test_boost_interval = 1;
1856	if (test_boost_duration < 2)
1857		test_boost_duration = 2;
1858	if ((test_boost == 1 && cur_ops->can_boost) ||
1859	    test_boost == 2) {
1860
1861		boost_starttime = jiffies + test_boost_interval * HZ;
1862
1863		firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE",
1864					     rcutorture_booster_init,
1865					     rcutorture_booster_cleanup);
1866		if (firsterr < 0)
1867			goto unwind;
1868		rcutor_hp = firsterr;
 
1869	}
1870	firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
1871	if (firsterr)
1872		goto unwind;
1873	firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval * HZ);
1874	if (firsterr)
1875		goto unwind;
1876	firsterr = rcu_torture_stall_init();
1877	if (firsterr)
1878		goto unwind;
1879	firsterr = rcu_torture_barrier_init();
1880	if (firsterr)
1881		goto unwind;
1882	if (object_debug)
1883		rcu_test_debug_objects();
1884	if (cbflood_n_burst > 0) {
1885		/* Create the cbflood threads */
1886		ncbflooders = (num_online_cpus() + 3) / 4;
1887		cbflood_task = kcalloc(ncbflooders, sizeof(*cbflood_task),
1888				       GFP_KERNEL);
1889		if (!cbflood_task) {
1890			VERBOSE_TOROUT_ERRSTRING("out of memory");
1891			firsterr = -ENOMEM;
1892			goto unwind;
1893		}
1894		for (i = 0; i < ncbflooders; i++) {
1895			firsterr = torture_create_kthread(rcu_torture_cbflood,
1896							  NULL,
1897							  cbflood_task[i]);
1898			if (firsterr)
1899				goto unwind;
1900		}
1901	}
1902	rcutorture_record_test_transition();
1903	torture_init_end();
1904	return 0;
1905
1906unwind:
1907	torture_init_end();
1908	rcu_torture_cleanup();
1909	return firsterr;
1910}
1911
1912module_init(rcu_torture_init);
1913module_exit(rcu_torture_cleanup);