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