1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * Read-Copy Update module-based torture test facility
   4 *
   5 * Copyright (C) IBM Corporation, 2005, 2006
   6 *
   7 * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
   8 *	  Josh Triplett <josh@joshtriplett.org>
   9 *
  10 * See also:  Documentation/RCU/torture.rst
  11 */
  12
  13#define pr_fmt(fmt) fmt
  14
  15#include <linux/types.h>
  16#include <linux/kernel.h>
  17#include <linux/init.h>
  18#include <linux/module.h>
  19#include <linux/kthread.h>
  20#include <linux/err.h>
  21#include <linux/spinlock.h>
  22#include <linux/smp.h>
  23#include <linux/rcupdate_wait.h>
 
  24#include <linux/interrupt.h>
  25#include <linux/sched/signal.h>
  26#include <uapi/linux/sched/types.h>
  27#include <linux/atomic.h>
  28#include <linux/bitops.h>
  29#include <linux/completion.h>
  30#include <linux/moduleparam.h>
  31#include <linux/percpu.h>
  32#include <linux/notifier.h>
  33#include <linux/reboot.h>
  34#include <linux/freezer.h>
  35#include <linux/cpu.h>
  36#include <linux/delay.h>
  37#include <linux/stat.h>
  38#include <linux/srcu.h>
  39#include <linux/slab.h>
  40#include <linux/trace_clock.h>
  41#include <asm/byteorder.h>
  42#include <linux/torture.h>
  43#include <linux/vmalloc.h>
  44#include <linux/sched/debug.h>
  45#include <linux/sched/sysctl.h>
  46#include <linux/oom.h>
  47#include <linux/tick.h>
  48#include <linux/rcupdate_trace.h>
 
  49
  50#include "rcu.h"
  51
 
  52MODULE_LICENSE("GPL");
  53MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
  54
  55#ifndef data_race
  56#define data_race(expr)							\
  57	({								\
  58		expr;							\
  59	})
  60#endif
  61#ifndef ASSERT_EXCLUSIVE_WRITER
  62#define ASSERT_EXCLUSIVE_WRITER(var) do { } while (0)
  63#endif
  64#ifndef ASSERT_EXCLUSIVE_ACCESS
  65#define ASSERT_EXCLUSIVE_ACCESS(var) do { } while (0)
  66#endif
  67
  68/* Bits for ->extendables field, extendables param, and related definitions. */
  69#define RCUTORTURE_RDR_SHIFT	 8	/* Put SRCU index in upper bits. */
  70#define RCUTORTURE_RDR_MASK	 ((1 << RCUTORTURE_RDR_SHIFT) - 1)
 
 
  71#define RCUTORTURE_RDR_BH	 0x01	/* Extend readers by disabling bh. */
  72#define RCUTORTURE_RDR_IRQ	 0x02	/*  ... disabling interrupts. */
  73#define RCUTORTURE_RDR_PREEMPT	 0x04	/*  ... disabling preemption. */
  74#define RCUTORTURE_RDR_RBH	 0x08	/*  ... rcu_read_lock_bh(). */
  75#define RCUTORTURE_RDR_SCHED	 0x10	/*  ... rcu_read_lock_sched(). */
  76#define RCUTORTURE_RDR_RCU	 0x20	/*  ... entering another RCU reader. */
  77#define RCUTORTURE_RDR_NBITS	 6	/* Number of bits defined above. */
 
  78#define RCUTORTURE_MAX_EXTEND	 \
  79	(RCUTORTURE_RDR_BH | RCUTORTURE_RDR_IRQ | RCUTORTURE_RDR_PREEMPT | \
  80	 RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED)
 
 
 
  81#define RCUTORTURE_RDR_MAX_LOOPS 0x7	/* Maximum reader extensions. */
  82					/* Must be power of two minus one. */
  83#define RCUTORTURE_RDR_MAX_SEGS (RCUTORTURE_RDR_MAX_LOOPS + 3)
  84
  85torture_param(int, extendables, RCUTORTURE_MAX_EXTEND,
  86	      "Extend readers by disabling bh (1), irqs (2), or preempt (4)");
  87torture_param(int, fqs_duration, 0,
  88	      "Duration of fqs bursts (us), 0 to disable");
  89torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
  90torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
  91torture_param(bool, fwd_progress, 1, "Test grace-period forward progress");
  92torture_param(int, fwd_progress_div, 4, "Fraction of CPU stall to wait");
  93torture_param(int, fwd_progress_holdoff, 60,
  94	      "Time between forward-progress tests (s)");
  95torture_param(bool, fwd_progress_need_resched, 1,
  96	      "Hide cond_resched() behind need_resched()");
  97torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
 
 
 
 
  98torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
  99torture_param(bool, gp_normal, false,
 100	     "Use normal (non-expedited) GP wait primitives");
 
 
 
 101torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
 102torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
 103torture_param(int, n_barrier_cbs, 0,
 104	     "# of callbacks/kthreads for barrier testing");
 105torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
 106torture_param(int, nreaders, -1, "Number of RCU reader threads");
 107torture_param(int, object_debug, 0,
 108	     "Enable debug-object double call_rcu() testing");
 109torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
 110torture_param(int, onoff_interval, 0,
 111	     "Time between CPU hotplugs (jiffies), 0=disable");
 112torture_param(int, read_exit_delay, 13,
 113	      "Delay between read-then-exit episodes (s)");
 114torture_param(int, read_exit_burst, 16,
 115	      "# of read-then-exit bursts per episode, zero to disable");
 116torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
 117torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
 118torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
 119torture_param(int, stall_cpu_holdoff, 10,
 120	     "Time to wait before starting stall (s).");
 121torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling.");
 122torture_param(int, stall_cpu_block, 0, "Sleep while stalling.");
 123torture_param(int, stall_gp_kthread, 0,
 124	      "Grace-period kthread stall duration (s).");
 125torture_param(int, stat_interval, 60,
 126	     "Number of seconds between stats printk()s");
 127torture_param(int, stutter, 5, "Number of seconds to run/halt test");
 128torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
 129torture_param(int, test_boost_duration, 4,
 130	     "Duration of each boost test, seconds.");
 131torture_param(int, test_boost_interval, 7,
 132	     "Interval between boost tests, seconds.");
 133torture_param(bool, test_no_idle_hz, true,
 134	     "Test support for tickless idle CPUs");
 135torture_param(int, verbose, 1,
 136	     "Enable verbose debugging printk()s");
 137
 138static char *torture_type = "rcu";
 139module_param(torture_type, charp, 0444);
 140MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, srcu, ...)");
 141
 
 142static int nrealreaders;
 143static struct task_struct *writer_task;
 144static struct task_struct **fakewriter_tasks;
 145static struct task_struct **reader_tasks;
 
 146static struct task_struct *stats_task;
 147static struct task_struct *fqs_task;
 148static struct task_struct *boost_tasks[NR_CPUS];
 149static struct task_struct *stall_task;
 150static struct task_struct *fwd_prog_task;
 151static struct task_struct **barrier_cbs_tasks;
 152static struct task_struct *barrier_task;
 153static struct task_struct *read_exit_task;
 154
 155#define RCU_TORTURE_PIPE_LEN 10
 156
 
 
 
 
 
 
 
 
 
 
 157struct rcu_torture {
 158	struct rcu_head rtort_rcu;
 159	int rtort_pipe_count;
 160	struct list_head rtort_free;
 161	int rtort_mbtest;
 
 162};
 163
 164static LIST_HEAD(rcu_torture_freelist);
 165static struct rcu_torture __rcu *rcu_torture_current;
 166static unsigned long rcu_torture_current_version;
 167static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
 168static DEFINE_SPINLOCK(rcu_torture_lock);
 169static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count);
 170static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch);
 171static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
 
 172static atomic_t n_rcu_torture_alloc;
 173static atomic_t n_rcu_torture_alloc_fail;
 174static atomic_t n_rcu_torture_free;
 175static atomic_t n_rcu_torture_mberror;
 
 
 176static atomic_t n_rcu_torture_error;
 177static long n_rcu_torture_barrier_error;
 178static long n_rcu_torture_boost_ktrerror;
 179static long n_rcu_torture_boost_rterror;
 180static long n_rcu_torture_boost_failure;
 181static long n_rcu_torture_boosts;
 182static atomic_long_t n_rcu_torture_timers;
 183static long n_barrier_attempts;
 184static long n_barrier_successes; /* did rcu_barrier test succeed? */
 185static unsigned long n_read_exits;
 186static struct list_head rcu_torture_removed;
 187static unsigned long shutdown_jiffies;
 
 
 
 188
 189static int rcu_torture_writer_state;
 190#define RTWS_FIXED_DELAY	0
 191#define RTWS_DELAY		1
 192#define RTWS_REPLACE		2
 193#define RTWS_DEF_FREE		3
 194#define RTWS_EXP_SYNC		4
 195#define RTWS_COND_GET		5
 196#define RTWS_COND_SYNC		6
 197#define RTWS_SYNC		7
 198#define RTWS_STUTTER		8
 199#define RTWS_STOPPING		9
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 200static const char * const rcu_torture_writer_state_names[] = {
 201	"RTWS_FIXED_DELAY",
 202	"RTWS_DELAY",
 203	"RTWS_REPLACE",
 204	"RTWS_DEF_FREE",
 205	"RTWS_EXP_SYNC",
 206	"RTWS_COND_GET",
 
 
 
 207	"RTWS_COND_SYNC",
 
 
 
 
 
 
 
 
 
 
 
 208	"RTWS_SYNC",
 209	"RTWS_STUTTER",
 210	"RTWS_STOPPING",
 211};
 212
 213/* Record reader segment types and duration for first failing read. */
 214struct rt_read_seg {
 215	int rt_readstate;
 216	unsigned long rt_delay_jiffies;
 217	unsigned long rt_delay_ms;
 218	unsigned long rt_delay_us;
 219	bool rt_preempted;
 220};
 221static int err_segs_recorded;
 222static struct rt_read_seg err_segs[RCUTORTURE_RDR_MAX_SEGS];
 223static int rt_read_nsegs;
 224
 225static const char *rcu_torture_writer_state_getname(void)
 226{
 227	unsigned int i = READ_ONCE(rcu_torture_writer_state);
 228
 229	if (i >= ARRAY_SIZE(rcu_torture_writer_state_names))
 230		return "???";
 231	return rcu_torture_writer_state_names[i];
 232}
 233
 234#if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
 235#define rcu_can_boost() 1
 236#else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
 237#define rcu_can_boost() 0
 238#endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
 239
 240#ifdef CONFIG_RCU_TRACE
 241static u64 notrace rcu_trace_clock_local(void)
 242{
 243	u64 ts = trace_clock_local();
 244
 245	(void)do_div(ts, NSEC_PER_USEC);
 246	return ts;
 247}
 248#else /* #ifdef CONFIG_RCU_TRACE */
 249static u64 notrace rcu_trace_clock_local(void)
 250{
 251	return 0ULL;
 252}
 253#endif /* #else #ifdef CONFIG_RCU_TRACE */
 254
 255/*
 256 * Stop aggressive CPU-hog tests a bit before the end of the test in order
 257 * to avoid interfering with test shutdown.
 258 */
 259static bool shutdown_time_arrived(void)
 260{
 261	return shutdown_secs && time_after(jiffies, shutdown_jiffies - 30 * HZ);
 262}
 263
 264static unsigned long boost_starttime;	/* jiffies of next boost test start. */
 265static DEFINE_MUTEX(boost_mutex);	/* protect setting boost_starttime */
 266					/*  and boost task create/destroy. */
 267static atomic_t barrier_cbs_count;	/* Barrier callbacks registered. */
 268static bool barrier_phase;		/* Test phase. */
 269static atomic_t barrier_cbs_invoked;	/* Barrier callbacks invoked. */
 270static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
 271static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
 272
 273static bool rcu_fwd_cb_nodelay;		/* Short rcu_torture_delay() delays. */
 274
 275/*
 276 * Allocate an element from the rcu_tortures pool.
 277 */
 278static struct rcu_torture *
 279rcu_torture_alloc(void)
 280{
 281	struct list_head *p;
 282
 283	spin_lock_bh(&rcu_torture_lock);
 284	if (list_empty(&rcu_torture_freelist)) {
 285		atomic_inc(&n_rcu_torture_alloc_fail);
 286		spin_unlock_bh(&rcu_torture_lock);
 287		return NULL;
 288	}
 289	atomic_inc(&n_rcu_torture_alloc);
 290	p = rcu_torture_freelist.next;
 291	list_del_init(p);
 292	spin_unlock_bh(&rcu_torture_lock);
 293	return container_of(p, struct rcu_torture, rtort_free);
 294}
 295
 296/*
 297 * Free an element to the rcu_tortures pool.
 298 */
 299static void
 300rcu_torture_free(struct rcu_torture *p)
 301{
 302	atomic_inc(&n_rcu_torture_free);
 303	spin_lock_bh(&rcu_torture_lock);
 304	list_add_tail(&p->rtort_free, &rcu_torture_freelist);
 305	spin_unlock_bh(&rcu_torture_lock);
 306}
 307
 308/*
 309 * Operations vector for selecting different types of tests.
 310 */
 311
 312struct rcu_torture_ops {
 313	int ttype;
 314	void (*init)(void);
 315	void (*cleanup)(void);
 316	int (*readlock)(void);
 317	void (*read_delay)(struct torture_random_state *rrsp,
 318			   struct rt_read_seg *rtrsp);
 319	void (*readunlock)(int idx);
 
 320	unsigned long (*get_gp_seq)(void);
 321	unsigned long (*gp_diff)(unsigned long new, unsigned long old);
 322	void (*deferred_free)(struct rcu_torture *p);
 323	void (*sync)(void);
 324	void (*exp_sync)(void);
 325	unsigned long (*get_state)(void);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 326	void (*cond_sync)(unsigned long oldstate);
 
 
 
 327	call_rcu_func_t call;
 328	void (*cb_barrier)(void);
 329	void (*fqs)(void);
 330	void (*stats)(void);
 
 
 331	int (*stall_dur)(void);
 
 
 
 
 332	int irq_capable;
 333	int can_boost;
 334	int extendables;
 335	int slow_gps;
 
 
 
 336	const char *name;
 337};
 338
 339static struct rcu_torture_ops *cur_ops;
 340
 341/*
 342 * Definitions for rcu torture testing.
 343 */
 344
 345static int rcu_torture_read_lock(void) __acquires(RCU)
 
 
 
 
 
 346{
 347	rcu_read_lock();
 348	return 0;
 349}
 350
 351static void
 352rcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
 353{
 354	unsigned long started;
 355	unsigned long completed;
 356	const unsigned long shortdelay_us = 200;
 357	unsigned long longdelay_ms = 300;
 358	unsigned long long ts;
 359
 360	/* We want a short delay sometimes to make a reader delay the grace
 361	 * period, and we want a long delay occasionally to trigger
 362	 * force_quiescent_state. */
 363
 364	if (!READ_ONCE(rcu_fwd_cb_nodelay) &&
 365	    !(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) {
 366		started = cur_ops->get_gp_seq();
 367		ts = rcu_trace_clock_local();
 368		if (preempt_count() & (SOFTIRQ_MASK | HARDIRQ_MASK))
 369			longdelay_ms = 5; /* Avoid triggering BH limits. */
 370		mdelay(longdelay_ms);
 371		rtrsp->rt_delay_ms = longdelay_ms;
 372		completed = cur_ops->get_gp_seq();
 373		do_trace_rcu_torture_read(cur_ops->name, NULL, ts,
 374					  started, completed);
 375	}
 376	if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) {
 377		udelay(shortdelay_us);
 378		rtrsp->rt_delay_us = shortdelay_us;
 379	}
 380	if (!preempt_count() &&
 381	    !(torture_random(rrsp) % (nrealreaders * 500))) {
 382		torture_preempt_schedule();  /* QS only if preemptible. */
 383		rtrsp->rt_preempted = true;
 384	}
 385}
 386
 387static void rcu_torture_read_unlock(int idx) __releases(RCU)
 388{
 389	rcu_read_unlock();
 390}
 391
 392/*
 393 * Update callback in the pipe.  This should be invoked after a grace period.
 394 */
 395static bool
 396rcu_torture_pipe_update_one(struct rcu_torture *rp)
 397{
 398	int i;
 
 399
 400	i = READ_ONCE(rp->rtort_pipe_count);
 
 
 
 
 401	if (i > RCU_TORTURE_PIPE_LEN)
 402		i = RCU_TORTURE_PIPE_LEN;
 403	atomic_inc(&rcu_torture_wcount[i]);
 404	WRITE_ONCE(rp->rtort_pipe_count, i + 1);
 405	if (rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
 
 406		rp->rtort_mbtest = 0;
 407		return true;
 408	}
 409	return false;
 410}
 411
 412/*
 413 * Update all callbacks in the pipe.  Suitable for synchronous grace-period
 414 * primitives.
 415 */
 416static void
 417rcu_torture_pipe_update(struct rcu_torture *old_rp)
 418{
 419	struct rcu_torture *rp;
 420	struct rcu_torture *rp1;
 421
 422	if (old_rp)
 423		list_add(&old_rp->rtort_free, &rcu_torture_removed);
 424	list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
 425		if (rcu_torture_pipe_update_one(rp)) {
 426			list_del(&rp->rtort_free);
 427			rcu_torture_free(rp);
 428		}
 429	}
 430}
 431
 432static void
 433rcu_torture_cb(struct rcu_head *p)
 434{
 435	struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
 436
 437	if (torture_must_stop_irq()) {
 438		/* Test is ending, just drop callbacks on the floor. */
 439		/* The next initialization will pick up the pieces. */
 440		return;
 441	}
 442	if (rcu_torture_pipe_update_one(rp))
 443		rcu_torture_free(rp);
 444	else
 445		cur_ops->deferred_free(rp);
 446}
 447
 448static unsigned long rcu_no_completed(void)
 449{
 450	return 0;
 451}
 452
 453static void rcu_torture_deferred_free(struct rcu_torture *p)
 454{
 455	call_rcu(&p->rtort_rcu, rcu_torture_cb);
 456}
 457
 458static void rcu_sync_torture_init(void)
 459{
 460	INIT_LIST_HEAD(&rcu_torture_removed);
 461}
 462
 
 
 
 
 
 463static struct rcu_torture_ops rcu_ops = {
 464	.ttype		= RCU_FLAVOR,
 465	.init		= rcu_sync_torture_init,
 466	.readlock	= rcu_torture_read_lock,
 467	.read_delay	= rcu_read_delay,
 468	.readunlock	= rcu_torture_read_unlock,
 469	.get_gp_seq	= rcu_get_gp_seq,
 470	.gp_diff	= rcu_seq_diff,
 471	.deferred_free	= rcu_torture_deferred_free,
 472	.sync		= synchronize_rcu,
 473	.exp_sync	= synchronize_rcu_expedited,
 474	.get_state	= get_state_synchronize_rcu,
 475	.cond_sync	= cond_synchronize_rcu,
 476	.call		= call_rcu,
 477	.cb_barrier	= rcu_barrier,
 478	.fqs		= rcu_force_quiescent_state,
 479	.stats		= NULL,
 480	.stall_dur	= rcu_jiffies_till_stall_check,
 481	.irq_capable	= 1,
 482	.can_boost	= rcu_can_boost(),
 483	.extendables	= RCUTORTURE_MAX_EXTEND,
 484	.name		= "rcu"
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 485};
 486
 487/*
 488 * Don't even think about trying any of these in real life!!!
 489 * The names includes "busted", and they really means it!
 490 * The only purpose of these functions is to provide a buggy RCU
 491 * implementation to make sure that rcutorture correctly emits
 492 * buggy-RCU error messages.
 493 */
 494static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
 495{
 496	/* This is a deliberate bug for testing purposes only! */
 497	rcu_torture_cb(&p->rtort_rcu);
 498}
 499
 500static void synchronize_rcu_busted(void)
 501{
 502	/* This is a deliberate bug for testing purposes only! */
 503}
 504
 505static void
 506call_rcu_busted(struct rcu_head *head, rcu_callback_t func)
 507{
 508	/* This is a deliberate bug for testing purposes only! */
 509	func(head);
 510}
 511
 512static struct rcu_torture_ops rcu_busted_ops = {
 513	.ttype		= INVALID_RCU_FLAVOR,
 514	.init		= rcu_sync_torture_init,
 515	.readlock	= rcu_torture_read_lock,
 516	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */
 517	.readunlock	= rcu_torture_read_unlock,
 
 518	.get_gp_seq	= rcu_no_completed,
 519	.deferred_free	= rcu_busted_torture_deferred_free,
 520	.sync		= synchronize_rcu_busted,
 521	.exp_sync	= synchronize_rcu_busted,
 522	.call		= call_rcu_busted,
 523	.cb_barrier	= NULL,
 524	.fqs		= NULL,
 525	.stats		= NULL,
 526	.irq_capable	= 1,
 527	.name		= "busted"
 528};
 529
 530/*
 531 * Definitions for srcu torture testing.
 532 */
 533
 534DEFINE_STATIC_SRCU(srcu_ctl);
 535static struct srcu_struct srcu_ctld;
 536static struct srcu_struct *srcu_ctlp = &srcu_ctl;
 
 
 
 
 
 
 537
 538static int srcu_torture_read_lock(void) __acquires(srcu_ctlp)
 539{
 540	return srcu_read_lock(srcu_ctlp);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 541}
 542
 543static void
 544srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
 545{
 546	long delay;
 547	const long uspertick = 1000000 / HZ;
 548	const long longdelay = 10;
 549
 550	/* We want there to be long-running readers, but not all the time. */
 551
 552	delay = torture_random(rrsp) %
 553		(nrealreaders * 2 * longdelay * uspertick);
 554	if (!delay && in_task()) {
 555		schedule_timeout_interruptible(longdelay);
 556		rtrsp->rt_delay_jiffies = longdelay;
 557	} else {
 558		rcu_read_delay(rrsp, rtrsp);
 559	}
 560}
 561
 562static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp)
 563{
 564	srcu_read_unlock(srcu_ctlp, idx);
 
 
 
 
 
 
 
 
 
 
 
 565}
 566
 567static unsigned long srcu_torture_completed(void)
 568{
 569	return srcu_batches_completed(srcu_ctlp);
 570}
 571
 572static void srcu_torture_deferred_free(struct rcu_torture *rp)
 573{
 574	call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
 575}
 576
 577static void srcu_torture_synchronize(void)
 578{
 579	synchronize_srcu(srcu_ctlp);
 580}
 581
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 582static void srcu_torture_call(struct rcu_head *head,
 583			      rcu_callback_t func)
 584{
 585	call_srcu(srcu_ctlp, head, func);
 586}
 587
 588static void srcu_torture_barrier(void)
 589{
 590	srcu_barrier(srcu_ctlp);
 591}
 592
 593static void srcu_torture_stats(void)
 594{
 595	srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG);
 596}
 597
 598static void srcu_torture_synchronize_expedited(void)
 599{
 600	synchronize_srcu_expedited(srcu_ctlp);
 601}
 602
 603static struct rcu_torture_ops srcu_ops = {
 604	.ttype		= SRCU_FLAVOR,
 605	.init		= rcu_sync_torture_init,
 606	.readlock	= srcu_torture_read_lock,
 607	.read_delay	= srcu_read_delay,
 608	.readunlock	= srcu_torture_read_unlock,
 
 609	.get_gp_seq	= 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		= "srcu"
 618};
 619
 620static void srcu_torture_init(void)
 621{
 622	rcu_sync_torture_init();
 623	WARN_ON(init_srcu_struct(&srcu_ctld));
 624	srcu_ctlp = &srcu_ctld;
 625}
 626
 627static void srcu_torture_cleanup(void)
 628{
 629	cleanup_srcu_struct(&srcu_ctld);
 630	srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
 631}
 632
 633/* As above, but dynamically allocated. */
 634static struct rcu_torture_ops srcud_ops = {
 635	.ttype		= SRCU_FLAVOR,
 636	.init		= srcu_torture_init,
 637	.cleanup	= srcu_torture_cleanup,
 638	.readlock	= srcu_torture_read_lock,
 639	.read_delay	= srcu_read_delay,
 640	.readunlock	= srcu_torture_read_unlock,
 
 641	.get_gp_seq	= srcu_torture_completed,
 642	.deferred_free	= srcu_torture_deferred_free,
 643	.sync		= srcu_torture_synchronize,
 644	.exp_sync	= srcu_torture_synchronize_expedited,
 
 
 
 
 
 
 645	.call		= srcu_torture_call,
 646	.cb_barrier	= srcu_torture_barrier,
 647	.stats		= srcu_torture_stats,
 
 
 648	.irq_capable	= 1,
 
 
 649	.name		= "srcud"
 650};
 651
 652/* As above, but broken due to inappropriate reader extension. */
 653static struct rcu_torture_ops busted_srcud_ops = {
 654	.ttype		= SRCU_FLAVOR,
 655	.init		= srcu_torture_init,
 656	.cleanup	= srcu_torture_cleanup,
 657	.readlock	= srcu_torture_read_lock,
 658	.read_delay	= rcu_read_delay,
 659	.readunlock	= srcu_torture_read_unlock,
 
 660	.get_gp_seq	= srcu_torture_completed,
 661	.deferred_free	= srcu_torture_deferred_free,
 662	.sync		= srcu_torture_synchronize,
 663	.exp_sync	= srcu_torture_synchronize_expedited,
 664	.call		= srcu_torture_call,
 665	.cb_barrier	= srcu_torture_barrier,
 666	.stats		= srcu_torture_stats,
 667	.irq_capable	= 1,
 
 668	.extendables	= RCUTORTURE_MAX_EXTEND,
 669	.name		= "busted_srcud"
 670};
 671
 672/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 673 * Definitions for RCU-tasks torture testing.
 674 */
 675
 676static int tasks_torture_read_lock(void)
 677{
 678	return 0;
 679}
 680
 681static void tasks_torture_read_unlock(int idx)
 682{
 683}
 684
 685static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
 686{
 687	call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
 688}
 689
 690static void synchronize_rcu_mult_test(void)
 691{
 692	synchronize_rcu_mult(call_rcu_tasks, call_rcu);
 693}
 694
 695static struct rcu_torture_ops tasks_ops = {
 696	.ttype		= RCU_TASKS_FLAVOR,
 697	.init		= rcu_sync_torture_init,
 698	.readlock	= tasks_torture_read_lock,
 699	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */
 700	.readunlock	= tasks_torture_read_unlock,
 701	.get_gp_seq	= rcu_no_completed,
 702	.deferred_free	= rcu_tasks_torture_deferred_free,
 703	.sync		= synchronize_rcu_tasks,
 704	.exp_sync	= synchronize_rcu_mult_test,
 705	.call		= call_rcu_tasks,
 706	.cb_barrier	= rcu_barrier_tasks,
 707	.fqs		= NULL,
 708	.stats		= NULL,
 709	.irq_capable	= 1,
 710	.slow_gps	= 1,
 711	.name		= "tasks"
 712};
 713
 714/*
 715 * Definitions for trivial CONFIG_PREEMPT=n-only torture testing.
 716 * This implementation does not necessarily work well with CPU hotplug.
 717 */
 718
 719static void synchronize_rcu_trivial(void)
 720{
 721	int cpu;
 722
 723	for_each_online_cpu(cpu) {
 724		rcutorture_sched_setaffinity(current->pid, cpumask_of(cpu));
 725		WARN_ON_ONCE(raw_smp_processor_id() != cpu);
 726	}
 727}
 728
 729static int rcu_torture_read_lock_trivial(void) __acquires(RCU)
 730{
 731	preempt_disable();
 732	return 0;
 733}
 734
 735static void rcu_torture_read_unlock_trivial(int idx) __releases(RCU)
 736{
 737	preempt_enable();
 738}
 739
 740static struct rcu_torture_ops trivial_ops = {
 741	.ttype		= RCU_TRIVIAL_FLAVOR,
 742	.init		= rcu_sync_torture_init,
 743	.readlock	= rcu_torture_read_lock_trivial,
 744	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */
 745	.readunlock	= rcu_torture_read_unlock_trivial,
 746	.get_gp_seq	= rcu_no_completed,
 747	.sync		= synchronize_rcu_trivial,
 748	.exp_sync	= synchronize_rcu_trivial,
 749	.fqs		= NULL,
 750	.stats		= NULL,
 751	.irq_capable	= 1,
 752	.name		= "trivial"
 753};
 754
 755/*
 756 * Definitions for rude RCU-tasks torture testing.
 757 */
 758
 759static void rcu_tasks_rude_torture_deferred_free(struct rcu_torture *p)
 760{
 761	call_rcu_tasks_rude(&p->rtort_rcu, rcu_torture_cb);
 762}
 763
 764static struct rcu_torture_ops tasks_rude_ops = {
 765	.ttype		= RCU_TASKS_RUDE_FLAVOR,
 766	.init		= rcu_sync_torture_init,
 767	.readlock	= rcu_torture_read_lock_trivial,
 768	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */
 769	.readunlock	= rcu_torture_read_unlock_trivial,
 770	.get_gp_seq	= rcu_no_completed,
 771	.deferred_free	= rcu_tasks_rude_torture_deferred_free,
 772	.sync		= synchronize_rcu_tasks_rude,
 773	.exp_sync	= synchronize_rcu_tasks_rude,
 774	.call		= call_rcu_tasks_rude,
 775	.cb_barrier	= rcu_barrier_tasks_rude,
 776	.fqs		= NULL,
 777	.stats		= NULL,
 778	.irq_capable	= 1,
 779	.name		= "tasks-rude"
 780};
 781
 
 
 
 
 
 
 
 
 
 
 
 782/*
 783 * Definitions for tracing RCU-tasks torture testing.
 784 */
 785
 786static int tasks_tracing_torture_read_lock(void)
 787{
 788	rcu_read_lock_trace();
 789	return 0;
 790}
 791
 792static void tasks_tracing_torture_read_unlock(int idx)
 793{
 794	rcu_read_unlock_trace();
 795}
 796
 797static void rcu_tasks_tracing_torture_deferred_free(struct rcu_torture *p)
 798{
 799	call_rcu_tasks_trace(&p->rtort_rcu, rcu_torture_cb);
 800}
 801
 802static struct rcu_torture_ops tasks_tracing_ops = {
 803	.ttype		= RCU_TASKS_TRACING_FLAVOR,
 804	.init		= rcu_sync_torture_init,
 805	.readlock	= tasks_tracing_torture_read_lock,
 806	.read_delay	= srcu_read_delay,  /* just reuse srcu's version. */
 807	.readunlock	= tasks_tracing_torture_read_unlock,
 
 808	.get_gp_seq	= rcu_no_completed,
 809	.deferred_free	= rcu_tasks_tracing_torture_deferred_free,
 810	.sync		= synchronize_rcu_tasks_trace,
 811	.exp_sync	= synchronize_rcu_tasks_trace,
 812	.call		= call_rcu_tasks_trace,
 813	.cb_barrier	= rcu_barrier_tasks_trace,
 814	.fqs		= NULL,
 815	.stats		= NULL,
 
 816	.irq_capable	= 1,
 817	.slow_gps	= 1,
 818	.name		= "tasks-tracing"
 819};
 820
 
 
 
 
 
 
 
 
 
 821static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old)
 822{
 823	if (!cur_ops->gp_diff)
 824		return new - old;
 825	return cur_ops->gp_diff(new, old);
 826}
 827
 828static bool __maybe_unused torturing_tasks(void)
 829{
 830	return cur_ops == &tasks_ops || cur_ops == &tasks_rude_ops;
 831}
 832
 833/*
 834 * RCU torture priority-boost testing.  Runs one real-time thread per
 835 * CPU for moderate bursts, repeatedly registering RCU callbacks and
 836 * spinning waiting for them to be invoked.  If a given callback takes
 837 * too long to be invoked, we assume that priority inversion has occurred.
 838 */
 839
 840struct rcu_boost_inflight {
 841	struct rcu_head rcu;
 842	int inflight;
 843};
 844
 845static void rcu_torture_boost_cb(struct rcu_head *head)
 846{
 847	struct rcu_boost_inflight *rbip =
 848		container_of(head, struct rcu_boost_inflight, rcu);
 849
 850	/* Ensure RCU-core accesses precede clearing ->inflight */
 851	smp_store_release(&rbip->inflight, 0);
 852}
 853
 854static int old_rt_runtime = -1;
 855
 856static void rcu_torture_disable_rt_throttle(void)
 857{
 858	/*
 859	 * Disable RT throttling so that rcutorture's boost threads don't get
 860	 * throttled. Only possible if rcutorture is built-in otherwise the
 861	 * user should manually do this by setting the sched_rt_period_us and
 862	 * sched_rt_runtime sysctls.
 863	 */
 864	if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime != -1)
 865		return;
 866
 867	old_rt_runtime = sysctl_sched_rt_runtime;
 868	sysctl_sched_rt_runtime = -1;
 869}
 870
 871static void rcu_torture_enable_rt_throttle(void)
 872{
 873	if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime == -1)
 874		return;
 875
 876	sysctl_sched_rt_runtime = old_rt_runtime;
 877	old_rt_runtime = -1;
 878}
 879
 880static bool rcu_torture_boost_failed(unsigned long start, unsigned long end)
 881{
 882	if (end - start > test_boost_duration * HZ - HZ / 2) {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 883		VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
 884		n_rcu_torture_boost_failure++;
 
 
 
 
 
 
 
 
 885
 886		return true; /* failed */
 
 
 
 
 887	}
 888
 889	return false; /* passed */
 890}
 891
 892static int rcu_torture_boost(void *arg)
 893{
 894	unsigned long call_rcu_time;
 895	unsigned long endtime;
 
 
 896	unsigned long oldstarttime;
 897	struct rcu_boost_inflight rbi = { .inflight = 0 };
 898
 899	VERBOSE_TOROUT_STRING("rcu_torture_boost started");
 900
 901	/* Set real-time priority. */
 902	sched_set_fifo_low(current);
 903
 904	init_rcu_head_on_stack(&rbi.rcu);
 905	/* Each pass through the following loop does one boost-test cycle. */
 906	do {
 907		/* Track if the test failed already in this test interval? */
 908		bool failed = false;
 909
 910		/* Increment n_rcu_torture_boosts once per boost-test */
 911		while (!kthread_should_stop()) {
 912			if (mutex_trylock(&boost_mutex)) {
 913				n_rcu_torture_boosts++;
 914				mutex_unlock(&boost_mutex);
 915				break;
 916			}
 917			schedule_timeout_uninterruptible(1);
 918		}
 919		if (kthread_should_stop())
 920			goto checkwait;
 921
 922		/* Wait for the next test interval. */
 923		oldstarttime = boost_starttime;
 924		while (time_before(jiffies, oldstarttime)) {
 925			schedule_timeout_interruptible(oldstarttime - jiffies);
 926			stutter_wait("rcu_torture_boost");
 
 927			if (torture_must_stop())
 928				goto checkwait;
 929		}
 930
 931		/* Do one boost-test interval. */
 932		endtime = oldstarttime + test_boost_duration * HZ;
 933		call_rcu_time = jiffies;
 934		while (time_before(jiffies, endtime)) {
 935			/* If we don't have a callback in flight, post one. */
 936			if (!smp_load_acquire(&rbi.inflight)) {
 937				/* RCU core before ->inflight = 1. */
 938				smp_store_release(&rbi.inflight, 1);
 939				call_rcu(&rbi.rcu, rcu_torture_boost_cb);
 940				/* Check if the boost test failed */
 941				failed = failed ||
 942					 rcu_torture_boost_failed(call_rcu_time,
 943								 jiffies);
 944				call_rcu_time = jiffies;
 
 
 
 
 
 
 945			}
 946			stutter_wait("rcu_torture_boost");
 947			if (torture_must_stop())
 948				goto checkwait;
 949		}
 950
 951		/*
 952		 * If boost never happened, then inflight will always be 1, in
 953		 * this case the boost check would never happen in the above
 954		 * loop so do another one here.
 955		 */
 956		if (!failed && smp_load_acquire(&rbi.inflight))
 957			rcu_torture_boost_failed(call_rcu_time, jiffies);
 958
 959		/*
 960		 * Set the start time of the next test interval.
 961		 * Yes, this is vulnerable to long delays, but such
 962		 * delays simply cause a false negative for the next
 963		 * interval.  Besides, we are running at RT priority,
 964		 * so delays should be relatively rare.
 965		 */
 966		while (oldstarttime == boost_starttime &&
 967		       !kthread_should_stop()) {
 968			if (mutex_trylock(&boost_mutex)) {
 969				boost_starttime = jiffies +
 970						  test_boost_interval * HZ;
 
 
 
 971				mutex_unlock(&boost_mutex);
 972				break;
 973			}
 974			schedule_timeout_uninterruptible(1);
 975		}
 976
 977		/* Go do the stutter. */
 978checkwait:	stutter_wait("rcu_torture_boost");
 
 979	} while (!torture_must_stop());
 980
 981	/* Clean up and exit. */
 982	while (!kthread_should_stop() || smp_load_acquire(&rbi.inflight)) {
 983		torture_shutdown_absorb("rcu_torture_boost");
 984		schedule_timeout_uninterruptible(1);
 985	}
 986	destroy_rcu_head_on_stack(&rbi.rcu);
 987	torture_kthread_stopping("rcu_torture_boost");
 988	return 0;
 989}
 990
 991/*
 992 * RCU torture force-quiescent-state kthread.  Repeatedly induces
 993 * bursts of calls to force_quiescent_state(), increasing the probability
 994 * of occurrence of some important types of race conditions.
 995 */
 996static int
 997rcu_torture_fqs(void *arg)
 998{
 999	unsigned long fqs_resume_time;
1000	int fqs_burst_remaining;
 
1001
1002	VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
1003	do {
1004		fqs_resume_time = jiffies + fqs_stutter * HZ;
1005		while (time_before(jiffies, fqs_resume_time) &&
1006		       !kthread_should_stop()) {
1007			schedule_timeout_interruptible(1);
1008		}
1009		fqs_burst_remaining = fqs_duration;
1010		while (fqs_burst_remaining > 0 &&
1011		       !kthread_should_stop()) {
1012			cur_ops->fqs();
1013			udelay(fqs_holdoff);
1014			fqs_burst_remaining -= fqs_holdoff;
1015		}
1016		stutter_wait("rcu_torture_fqs");
 
1017	} while (!torture_must_stop());
1018	torture_kthread_stopping("rcu_torture_fqs");
1019	return 0;
1020}
1021
 
 
 
 
1022/*
1023 * RCU torture writer kthread.  Repeatedly substitutes a new structure
1024 * for that pointed to by rcu_torture_current, freeing the old structure
1025 * after a series of grace periods (the "pipeline").
1026 */
1027static int
1028rcu_torture_writer(void *arg)
1029{
1030	bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
1031	int expediting = 0;
1032	unsigned long gp_snap;
1033	bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal;
1034	bool gp_sync1 = gp_sync;
1035	int i;
1036	struct rcu_torture *rp;
1037	struct rcu_torture *old_rp;
1038	static DEFINE_TORTURE_RANDOM(rand);
1039	int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC,
1040			   RTWS_COND_GET, RTWS_SYNC };
1041	int nsynctypes = 0;
1042
1043	VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
1044	if (!can_expedite)
1045		pr_alert("%s" TORTURE_FLAG
1046			 " GP expediting controlled from boot/sysfs for %s.\n",
1047			 torture_type, cur_ops->name);
1048
1049	/* Initialize synctype[] array.  If none set, take default. */
1050	if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync1)
1051		gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true;
1052	if (gp_cond1 && cur_ops->get_state && cur_ops->cond_sync) {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1053		synctype[nsynctypes++] = RTWS_COND_GET;
1054		pr_info("%s: Testing conditional GPs.\n", __func__);
1055	} else if (gp_cond && (!cur_ops->get_state || !cur_ops->cond_sync)) {
1056		pr_alert("%s: gp_cond without primitives.\n", __func__);
1057	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1058	if (gp_exp1 && cur_ops->exp_sync) {
1059		synctype[nsynctypes++] = RTWS_EXP_SYNC;
1060		pr_info("%s: Testing expedited GPs.\n", __func__);
1061	} else if (gp_exp && !cur_ops->exp_sync) {
1062		pr_alert("%s: gp_exp without primitives.\n", __func__);
1063	}
1064	if (gp_normal1 && cur_ops->deferred_free) {
1065		synctype[nsynctypes++] = RTWS_DEF_FREE;
1066		pr_info("%s: Testing asynchronous GPs.\n", __func__);
1067	} else if (gp_normal && !cur_ops->deferred_free) {
1068		pr_alert("%s: gp_normal without primitives.\n", __func__);
1069	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1070	if (gp_sync1 && cur_ops->sync) {
1071		synctype[nsynctypes++] = RTWS_SYNC;
1072		pr_info("%s: Testing normal GPs.\n", __func__);
1073	} else if (gp_sync && !cur_ops->sync) {
1074		pr_alert("%s: gp_sync without primitives.\n", __func__);
1075	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1076	if (WARN_ONCE(nsynctypes == 0,
1077		      "rcu_torture_writer: No update-side primitives.\n")) {
1078		/*
1079		 * No updates primitives, so don't try updating.
1080		 * The resulting test won't be testing much, hence the
1081		 * above WARN_ONCE().
1082		 */
1083		rcu_torture_writer_state = RTWS_STOPPING;
1084		torture_kthread_stopping("rcu_torture_writer");
 
 
 
 
 
 
 
 
 
 
 
1085	}
1086
1087	do {
1088		rcu_torture_writer_state = RTWS_FIXED_DELAY;
1089		schedule_timeout_uninterruptible(1);
1090		rp = rcu_torture_alloc();
1091		if (rp == NULL)
1092			continue;
1093		rp->rtort_pipe_count = 0;
 
1094		rcu_torture_writer_state = RTWS_DELAY;
1095		udelay(torture_random(&rand) & 0x3ff);
1096		rcu_torture_writer_state = RTWS_REPLACE;
1097		old_rp = rcu_dereference_check(rcu_torture_current,
1098					       current == writer_task);
1099		rp->rtort_mbtest = 1;
1100		rcu_assign_pointer(rcu_torture_current, rp);
1101		smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
1102		if (old_rp) {
1103			i = old_rp->rtort_pipe_count;
1104			if (i > RCU_TORTURE_PIPE_LEN)
1105				i = RCU_TORTURE_PIPE_LEN;
1106			atomic_inc(&rcu_torture_wcount[i]);
1107			WRITE_ONCE(old_rp->rtort_pipe_count,
1108				   old_rp->rtort_pipe_count + 1);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1109			switch (synctype[torture_random(&rand) % nsynctypes]) {
1110			case RTWS_DEF_FREE:
1111				rcu_torture_writer_state = RTWS_DEF_FREE;
1112				cur_ops->deferred_free(old_rp);
1113				break;
1114			case RTWS_EXP_SYNC:
1115				rcu_torture_writer_state = RTWS_EXP_SYNC;
1116				cur_ops->exp_sync();
1117				rcu_torture_pipe_update(old_rp);
1118				break;
1119			case RTWS_COND_GET:
1120				rcu_torture_writer_state = RTWS_COND_GET;
1121				gp_snap = cur_ops->get_state();
1122				i = torture_random(&rand) % 16;
1123				if (i != 0)
1124					schedule_timeout_interruptible(i);
1125				udelay(torture_random(&rand) % 1000);
1126				rcu_torture_writer_state = RTWS_COND_SYNC;
1127				cur_ops->cond_sync(gp_snap);
1128				rcu_torture_pipe_update(old_rp);
1129				break;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1130			case RTWS_SYNC:
1131				rcu_torture_writer_state = RTWS_SYNC;
1132				cur_ops->sync();
1133				rcu_torture_pipe_update(old_rp);
1134				break;
1135			default:
1136				WARN_ON_ONCE(1);
1137				break;
1138			}
1139		}
1140		WRITE_ONCE(rcu_torture_current_version,
1141			   rcu_torture_current_version + 1);
1142		/* Cycle through nesting levels of rcu_expedite_gp() calls. */
1143		if (can_expedite &&
1144		    !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
1145			WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
1146			if (expediting >= 0)
1147				rcu_expedite_gp();
1148			else
1149				rcu_unexpedite_gp();
1150			if (++expediting > 3)
1151				expediting = -expediting;
1152		} else if (!can_expedite) { /* Disabled during boot, recheck. */
1153			can_expedite = !rcu_gp_is_expedited() &&
1154				       !rcu_gp_is_normal();
1155		}
1156		rcu_torture_writer_state = RTWS_STUTTER;
1157		if (stutter_wait("rcu_torture_writer") &&
1158		    !READ_ONCE(rcu_fwd_cb_nodelay) &&
 
 
1159		    !cur_ops->slow_gps &&
1160		    !torture_must_stop() &&
1161		    rcu_inkernel_boot_has_ended())
 
1162			for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++)
1163				if (list_empty(&rcu_tortures[i].rtort_free) &&
1164				    rcu_access_pointer(rcu_torture_current) !=
1165				    &rcu_tortures[i]) {
1166					rcu_ftrace_dump(DUMP_ALL);
 
1167					WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count);
 
1168				}
 
 
1169	} while (!torture_must_stop());
1170	rcu_torture_current = NULL;  // Let stats task know that we are done.
1171	/* Reset expediting back to unexpedited. */
1172	if (expediting > 0)
1173		expediting = -expediting;
1174	while (can_expedite && expediting++ < 0)
1175		rcu_unexpedite_gp();
1176	WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
1177	if (!can_expedite)
1178		pr_alert("%s" TORTURE_FLAG
1179			 " Dynamic grace-period expediting was disabled.\n",
1180			 torture_type);
 
 
1181	rcu_torture_writer_state = RTWS_STOPPING;
1182	torture_kthread_stopping("rcu_torture_writer");
1183	return 0;
1184}
1185
1186/*
1187 * RCU torture fake writer kthread.  Repeatedly calls sync, with a random
1188 * delay between calls.
1189 */
1190static int
1191rcu_torture_fakewriter(void *arg)
1192{
 
 
1193	DEFINE_TORTURE_RANDOM(rand);
1194
1195	VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1196	set_user_nice(current, MAX_NICE);
1197
 
 
 
 
 
 
 
 
 
 
 
1198	do {
1199		schedule_timeout_uninterruptible(1 + torture_random(&rand)%10);
1200		udelay(torture_random(&rand) & 0x3ff);
1201		if (cur_ops->cb_barrier != NULL &&
1202		    torture_random(&rand) % (nfakewriters * 8) == 0) {
1203			cur_ops->cb_barrier();
1204		} else if (gp_normal == gp_exp) {
1205			if (cur_ops->sync && torture_random(&rand) & 0x80)
1206				cur_ops->sync();
1207			else if (cur_ops->exp_sync)
 
1208				cur_ops->exp_sync();
1209		} else if (gp_normal && cur_ops->sync) {
1210			cur_ops->sync();
1211		} else if (cur_ops->exp_sync) {
1212			cur_ops->exp_sync();
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1213		}
1214		stutter_wait("rcu_torture_fakewriter");
1215	} while (!torture_must_stop());
1216
1217	torture_kthread_stopping("rcu_torture_fakewriter");
1218	return 0;
1219}
1220
1221static void rcu_torture_timer_cb(struct rcu_head *rhp)
1222{
1223	kfree(rhp);
1224}
1225
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1226/*
1227 * Do one extension of an RCU read-side critical section using the
1228 * current reader state in readstate (set to zero for initial entry
1229 * to extended critical section), set the new state as specified by
1230 * newstate (set to zero for final exit from extended critical section),
1231 * and random-number-generator state in trsp.  If this is neither the
1232 * beginning or end of the critical section and if there was actually a
1233 * change, do a ->read_delay().
1234 */
1235static void rcutorture_one_extend(int *readstate, int newstate,
1236				  struct torture_random_state *trsp,
1237				  struct rt_read_seg *rtrsp)
1238{
1239	unsigned long flags;
1240	int idxnew = -1;
1241	int idxold = *readstate;
 
 
1242	int statesnew = ~*readstate & newstate;
1243	int statesold = *readstate & ~newstate;
1244
1245	WARN_ON_ONCE(idxold < 0);
1246	WARN_ON_ONCE((idxold >> RCUTORTURE_RDR_SHIFT) > 1);
1247	rtrsp->rt_readstate = newstate;
1248
1249	/* First, put new protection in place to avoid critical-section gap. */
1250	if (statesnew & RCUTORTURE_RDR_BH)
1251		local_bh_disable();
 
 
1252	if (statesnew & RCUTORTURE_RDR_IRQ)
1253		local_irq_disable();
1254	if (statesnew & RCUTORTURE_RDR_PREEMPT)
1255		preempt_disable();
1256	if (statesnew & RCUTORTURE_RDR_RBH)
1257		rcu_read_lock_bh();
1258	if (statesnew & RCUTORTURE_RDR_SCHED)
1259		rcu_read_lock_sched();
1260	if (statesnew & RCUTORTURE_RDR_RCU)
1261		idxnew = cur_ops->readlock() << RCUTORTURE_RDR_SHIFT;
 
 
1262
1263	/* Next, remove old protection, irq first due to bh conflict. */
 
 
 
 
 
 
1264	if (statesold & RCUTORTURE_RDR_IRQ)
1265		local_irq_enable();
1266	if (statesold & RCUTORTURE_RDR_BH)
1267		local_bh_enable();
1268	if (statesold & RCUTORTURE_RDR_PREEMPT)
1269		preempt_enable();
1270	if (statesold & RCUTORTURE_RDR_RBH)
1271		rcu_read_unlock_bh();
1272	if (statesold & RCUTORTURE_RDR_SCHED)
1273		rcu_read_unlock_sched();
1274	if (statesold & RCUTORTURE_RDR_RCU) {
1275		bool lockit = !statesnew && !(torture_random(trsp) & 0xffff);
 
 
 
 
 
 
 
 
 
1276
 
1277		if (lockit)
1278			raw_spin_lock_irqsave(&current->pi_lock, flags);
1279		cur_ops->readunlock(idxold >> RCUTORTURE_RDR_SHIFT);
 
 
1280		if (lockit)
1281			raw_spin_unlock_irqrestore(&current->pi_lock, flags);
1282	}
1283
1284	/* Delay if neither beginning nor end and there was a change. */
1285	if ((statesnew || statesold) && *readstate && newstate)
1286		cur_ops->read_delay(trsp, rtrsp);
1287
1288	/* Update the reader state. */
1289	if (idxnew == -1)
1290		idxnew = idxold & ~RCUTORTURE_RDR_MASK;
1291	WARN_ON_ONCE(idxnew < 0);
1292	WARN_ON_ONCE((idxnew >> RCUTORTURE_RDR_SHIFT) > 1);
1293	*readstate = idxnew | newstate;
1294	WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT) < 0);
1295	WARN_ON_ONCE((*readstate >> RCUTORTURE_RDR_SHIFT) > 1);
 
 
 
1296}
1297
1298/* Return the biggest extendables mask given current RCU and boot parameters. */
1299static int rcutorture_extend_mask_max(void)
1300{
1301	int mask;
1302
1303	WARN_ON_ONCE(extendables & ~RCUTORTURE_MAX_EXTEND);
1304	mask = extendables & RCUTORTURE_MAX_EXTEND & cur_ops->extendables;
1305	mask = mask | RCUTORTURE_RDR_RCU;
1306	return mask;
1307}
1308
1309/* Return a random protection state mask, but with at least one bit set. */
1310static int
1311rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp)
1312{
1313	int mask = rcutorture_extend_mask_max();
1314	unsigned long randmask1 = torture_random(trsp) >> 8;
1315	unsigned long randmask2 = randmask1 >> 3;
 
 
 
1316
1317	WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT);
1318	/* Mostly only one bit (need preemption!), sometimes lots of bits. */
1319	if (!(randmask1 & 0x7))
1320		mask = mask & randmask2;
1321	else
1322		mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS));
1323	/* Can't enable bh w/irq disabled. */
1324	if ((mask & RCUTORTURE_RDR_IRQ) &&
1325	    ((!(mask & RCUTORTURE_RDR_BH) && (oldmask & RCUTORTURE_RDR_BH)) ||
1326	     (!(mask & RCUTORTURE_RDR_RBH) && (oldmask & RCUTORTURE_RDR_RBH))))
1327		mask |= RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH;
1328	return mask ?: RCUTORTURE_RDR_RCU;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1329}
1330
1331/*
1332 * Do a randomly selected number of extensions of an existing RCU read-side
1333 * critical section.
1334 */
1335static struct rt_read_seg *
1336rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp,
1337		       struct rt_read_seg *rtrsp)
1338{
1339	int i;
1340	int j;
1341	int mask = rcutorture_extend_mask_max();
1342
1343	WARN_ON_ONCE(!*readstate); /* -Existing- RCU read-side critsect! */
1344	if (!((mask - 1) & mask))
1345		return rtrsp;  /* Current RCU reader not extendable. */
1346	/* Bias towards larger numbers of loops. */
1347	i = (torture_random(trsp) >> 3);
1348	i = ((i | (i >> 3)) & RCUTORTURE_RDR_MAX_LOOPS) + 1;
1349	for (j = 0; j < i; j++) {
1350		mask = rcutorture_extend_mask(*readstate, trsp);
1351		rcutorture_one_extend(readstate, mask, trsp, &rtrsp[j]);
1352	}
1353	return &rtrsp[j];
1354}
1355
1356/*
1357 * Do one read-side critical section, returning false if there was
1358 * no data to read.  Can be invoked both from process context and
1359 * from a timer handler.
1360 */
1361static bool rcu_torture_one_read(struct torture_random_state *trsp)
1362{
 
 
 
1363	int i;
1364	unsigned long started;
1365	unsigned long completed;
1366	int newstate;
1367	struct rcu_torture *p;
1368	int pipe_count;
1369	int readstate = 0;
1370	struct rt_read_seg rtseg[RCUTORTURE_RDR_MAX_SEGS] = { { 0 } };
1371	struct rt_read_seg *rtrsp = &rtseg[0];
1372	struct rt_read_seg *rtrsp1;
1373	unsigned long long ts;
1374
1375	WARN_ON_ONCE(!rcu_is_watching());
1376	newstate = rcutorture_extend_mask(readstate, trsp);
1377	rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++);
 
 
 
 
 
 
1378	started = cur_ops->get_gp_seq();
1379	ts = rcu_trace_clock_local();
1380	p = rcu_dereference_check(rcu_torture_current,
1381				  rcu_read_lock_bh_held() ||
1382				  rcu_read_lock_sched_held() ||
1383				  srcu_read_lock_held(srcu_ctlp) ||
1384				  rcu_read_lock_trace_held() ||
1385				  torturing_tasks());
1386	if (p == NULL) {
1387		/* Wait for rcu_torture_writer to get underway */
1388		rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
1389		return false;
1390	}
1391	if (p->rtort_mbtest == 0)
1392		atomic_inc(&n_rcu_torture_mberror);
 
1393	rtrsp = rcutorture_loop_extend(&readstate, trsp, rtrsp);
1394	preempt_disable();
1395	pipe_count = READ_ONCE(p->rtort_pipe_count);
1396	if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1397		/* Should not happen, but... */
 
1398		pipe_count = RCU_TORTURE_PIPE_LEN;
1399	}
1400	completed = cur_ops->get_gp_seq();
1401	if (pipe_count > 1) {
1402		do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
1403					  ts, started, completed);
1404		rcu_ftrace_dump(DUMP_ALL);
1405	}
1406	__this_cpu_inc(rcu_torture_count[pipe_count]);
1407	completed = rcutorture_seq_diff(completed, started);
1408	if (completed > RCU_TORTURE_PIPE_LEN) {
1409		/* Should not happen, but... */
1410		completed = RCU_TORTURE_PIPE_LEN;
1411	}
1412	__this_cpu_inc(rcu_torture_batch[completed]);
1413	preempt_enable();
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1414	rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
1415	WARN_ON_ONCE(readstate & RCUTORTURE_RDR_MASK);
 
 
 
1416
1417	/* If error or close call, record the sequence of reader protections. */
1418	if ((pipe_count > 1 || completed > 1) && !xchg(&err_segs_recorded, 1)) {
1419		i = 0;
1420		for (rtrsp1 = &rtseg[0]; rtrsp1 < rtrsp; rtrsp1++)
1421			err_segs[i++] = *rtrsp1;
1422		rt_read_nsegs = i;
1423	}
1424
1425	return true;
1426}
1427
1428static DEFINE_TORTURE_RANDOM_PERCPU(rcu_torture_timer_rand);
1429
1430/*
1431 * RCU torture reader from timer handler.  Dereferences rcu_torture_current,
1432 * incrementing the corresponding element of the pipeline array.  The
1433 * counter in the element should never be greater than 1, otherwise, the
1434 * RCU implementation is broken.
1435 */
1436static void rcu_torture_timer(struct timer_list *unused)
1437{
1438	atomic_long_inc(&n_rcu_torture_timers);
1439	(void)rcu_torture_one_read(this_cpu_ptr(&rcu_torture_timer_rand));
1440
1441	/* Test call_rcu() invocation from interrupt handler. */
1442	if (cur_ops->call) {
1443		struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT);
1444
1445		if (rhp)
1446			cur_ops->call(rhp, rcu_torture_timer_cb);
1447	}
1448}
1449
1450/*
1451 * RCU torture reader kthread.  Repeatedly dereferences rcu_torture_current,
1452 * incrementing the corresponding element of the pipeline array.  The
1453 * counter in the element should never be greater than 1, otherwise, the
1454 * RCU implementation is broken.
1455 */
1456static int
1457rcu_torture_reader(void *arg)
1458{
1459	unsigned long lastsleep = jiffies;
1460	long myid = (long)arg;
1461	int mynumonline = myid;
1462	DEFINE_TORTURE_RANDOM(rand);
1463	struct timer_list t;
1464
1465	VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
1466	set_user_nice(current, MAX_NICE);
1467	if (irqreader && cur_ops->irq_capable)
1468		timer_setup_on_stack(&t, rcu_torture_timer, 0);
1469	tick_dep_set_task(current, TICK_DEP_BIT_RCU);
1470	do {
1471		if (irqreader && cur_ops->irq_capable) {
1472			if (!timer_pending(&t))
1473				mod_timer(&t, jiffies + 1);
1474		}
1475		if (!rcu_torture_one_read(&rand) && !torture_must_stop())
1476			schedule_timeout_interruptible(HZ);
1477		if (time_after(jiffies, lastsleep) && !torture_must_stop()) {
1478			schedule_timeout_interruptible(1);
1479			lastsleep = jiffies + 10;
1480		}
1481		while (num_online_cpus() < mynumonline && !torture_must_stop())
1482			schedule_timeout_interruptible(HZ / 5);
1483		stutter_wait("rcu_torture_reader");
1484	} while (!torture_must_stop());
1485	if (irqreader && cur_ops->irq_capable) {
1486		del_timer_sync(&t);
1487		destroy_timer_on_stack(&t);
1488	}
1489	tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
1490	torture_kthread_stopping("rcu_torture_reader");
1491	return 0;
1492}
1493
1494/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1495 * Print torture statistics.  Caller must ensure that there is only
1496 * one call to this function at a given time!!!  This is normally
1497 * accomplished by relying on the module system to only have one copy
1498 * of the module loaded, and then by giving the rcu_torture_stats
1499 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1500 * thread is not running).
1501 */
1502static void
1503rcu_torture_stats_print(void)
1504{
1505	int cpu;
1506	int i;
1507	long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1508	long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1509	struct rcu_torture *rtcp;
1510	static unsigned long rtcv_snap = ULONG_MAX;
1511	static bool splatted;
1512	struct task_struct *wtp;
1513
1514	for_each_possible_cpu(cpu) {
1515		for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1516			pipesummary[i] += READ_ONCE(per_cpu(rcu_torture_count, cpu)[i]);
1517			batchsummary[i] += READ_ONCE(per_cpu(rcu_torture_batch, cpu)[i]);
1518		}
1519	}
1520	for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
1521		if (pipesummary[i] != 0)
1522			break;
1523	}
1524
1525	pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1526	rtcp = rcu_access_pointer(rcu_torture_current);
1527	pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
1528		rtcp,
1529		rtcp && !rcu_stall_is_suppressed_at_boot() ? "ver" : "VER",
1530		rcu_torture_current_version,
1531		list_empty(&rcu_torture_freelist),
1532		atomic_read(&n_rcu_torture_alloc),
1533		atomic_read(&n_rcu_torture_alloc_fail),
1534		atomic_read(&n_rcu_torture_free));
1535	pr_cont("rtmbe: %d rtbe: %ld rtbke: %ld rtbre: %ld ",
1536		atomic_read(&n_rcu_torture_mberror),
 
1537		n_rcu_torture_barrier_error,
1538		n_rcu_torture_boost_ktrerror,
1539		n_rcu_torture_boost_rterror);
1540	pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
1541		n_rcu_torture_boost_failure,
1542		n_rcu_torture_boosts,
1543		atomic_long_read(&n_rcu_torture_timers));
1544	torture_onoff_stats();
1545	pr_cont("barrier: %ld/%ld:%ld ",
1546		data_race(n_barrier_successes),
1547		data_race(n_barrier_attempts),
1548		data_race(n_rcu_torture_barrier_error));
1549	pr_cont("read-exits: %ld\n", data_race(n_read_exits));
 
 
1550
1551	pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1552	if (atomic_read(&n_rcu_torture_mberror) ||
 
1553	    n_rcu_torture_barrier_error || n_rcu_torture_boost_ktrerror ||
1554	    n_rcu_torture_boost_rterror || n_rcu_torture_boost_failure ||
1555	    i > 1) {
1556		pr_cont("%s", "!!! ");
1557		atomic_inc(&n_rcu_torture_error);
1558		WARN_ON_ONCE(atomic_read(&n_rcu_torture_mberror));
 
1559		WARN_ON_ONCE(n_rcu_torture_barrier_error);  // rcu_barrier()
1560		WARN_ON_ONCE(n_rcu_torture_boost_ktrerror); // no boost kthread
1561		WARN_ON_ONCE(n_rcu_torture_boost_rterror); // can't set RT prio
1562		WARN_ON_ONCE(n_rcu_torture_boost_failure); // RCU boost failed
1563		WARN_ON_ONCE(i > 1); // Too-short grace period
1564	}
1565	pr_cont("Reader Pipe: ");
1566	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1567		pr_cont(" %ld", pipesummary[i]);
1568	pr_cont("\n");
1569
1570	pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1571	pr_cont("Reader Batch: ");
1572	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1573		pr_cont(" %ld", batchsummary[i]);
1574	pr_cont("\n");
1575
1576	pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1577	pr_cont("Free-Block Circulation: ");
1578	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1579		pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
1580	}
1581	pr_cont("\n");
1582
1583	if (cur_ops->stats)
1584		cur_ops->stats();
1585	if (rtcv_snap == rcu_torture_current_version &&
1586	    rcu_access_pointer(rcu_torture_current) &&
1587	    !rcu_stall_is_suppressed()) {
1588		int __maybe_unused flags = 0;
1589		unsigned long __maybe_unused gp_seq = 0;
1590
1591		rcutorture_get_gp_data(cur_ops->ttype,
1592				       &flags, &gp_seq);
1593		srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp,
1594					&flags, &gp_seq);
1595		wtp = READ_ONCE(writer_task);
1596		pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#lx cpu %d\n",
1597			 rcu_torture_writer_state_getname(),
1598			 rcu_torture_writer_state, gp_seq, flags,
1599			 wtp == NULL ? ~0UL : wtp->state,
1600			 wtp == NULL ? -1 : (int)task_cpu(wtp));
1601		if (!splatted && wtp) {
1602			sched_show_task(wtp);
1603			splatted = true;
1604		}
1605		show_rcu_gp_kthreads();
 
1606		rcu_ftrace_dump(DUMP_ALL);
1607	}
1608	rtcv_snap = rcu_torture_current_version;
1609}
1610
1611/*
1612 * Periodically prints torture statistics, if periodic statistics printing
1613 * was specified via the stat_interval module parameter.
1614 */
1615static int
1616rcu_torture_stats(void *arg)
1617{
1618	VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1619	do {
1620		schedule_timeout_interruptible(stat_interval * HZ);
1621		rcu_torture_stats_print();
1622		torture_shutdown_absorb("rcu_torture_stats");
1623	} while (!torture_must_stop());
1624	torture_kthread_stopping("rcu_torture_stats");
1625	return 0;
1626}
1627
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1628static void
1629rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1630{
1631	pr_alert("%s" TORTURE_FLAG
1632		 "--- %s: nreaders=%d nfakewriters=%d "
1633		 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1634		 "shuffle_interval=%d stutter=%d irqreader=%d "
1635		 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1636		 "test_boost=%d/%d test_boost_interval=%d "
1637		 "test_boost_duration=%d shutdown_secs=%d "
1638		 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d "
1639		 "stall_cpu_block=%d "
1640		 "n_barrier_cbs=%d "
1641		 "onoff_interval=%d onoff_holdoff=%d "
1642		 "read_exit_delay=%d read_exit_burst=%d\n",
 
 
 
1643		 torture_type, tag, nrealreaders, nfakewriters,
1644		 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1645		 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1646		 test_boost, cur_ops->can_boost,
1647		 test_boost_interval, test_boost_duration, shutdown_secs,
1648		 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff,
1649		 stall_cpu_block,
1650		 n_barrier_cbs,
1651		 onoff_interval, onoff_holdoff,
1652		 read_exit_delay, read_exit_burst);
 
 
 
1653}
1654
1655static int rcutorture_booster_cleanup(unsigned int cpu)
1656{
1657	struct task_struct *t;
1658
1659	if (boost_tasks[cpu] == NULL)
1660		return 0;
1661	mutex_lock(&boost_mutex);
1662	t = boost_tasks[cpu];
1663	boost_tasks[cpu] = NULL;
1664	rcu_torture_enable_rt_throttle();
1665	mutex_unlock(&boost_mutex);
1666
1667	/* This must be outside of the mutex, otherwise deadlock! */
1668	torture_stop_kthread(rcu_torture_boost, t);
1669	return 0;
1670}
1671
1672static int rcutorture_booster_init(unsigned int cpu)
1673{
1674	int retval;
1675
1676	if (boost_tasks[cpu] != NULL)
1677		return 0;  /* Already created, nothing more to do. */
1678
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1679	/* Don't allow time recalculation while creating a new task. */
1680	mutex_lock(&boost_mutex);
1681	rcu_torture_disable_rt_throttle();
1682	VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
1683	boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
1684						  cpu_to_node(cpu),
1685						  "rcu_torture_boost");
1686	if (IS_ERR(boost_tasks[cpu])) {
1687		retval = PTR_ERR(boost_tasks[cpu]);
1688		VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
1689		n_rcu_torture_boost_ktrerror++;
1690		boost_tasks[cpu] = NULL;
1691		mutex_unlock(&boost_mutex);
1692		return retval;
1693	}
1694	kthread_bind(boost_tasks[cpu], cpu);
1695	wake_up_process(boost_tasks[cpu]);
1696	mutex_unlock(&boost_mutex);
1697	return 0;
1698}
1699
 
 
 
 
 
 
 
 
 
 
1700/*
1701 * CPU-stall kthread.  It waits as specified by stall_cpu_holdoff, then
1702 * induces a CPU stall for the time specified by stall_cpu.
 
1703 */
1704static int rcu_torture_stall(void *args)
1705{
1706	int idx;
1707	unsigned long stop_at;
1708
1709	VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
1710	if (stall_cpu_holdoff > 0) {
1711		VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
1712		schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
1713		VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
1714	}
1715	if (!kthread_should_stop() && stall_gp_kthread > 0) {
1716		VERBOSE_TOROUT_STRING("rcu_torture_stall begin GP stall");
1717		rcu_gp_set_torture_wait(stall_gp_kthread * HZ);
1718		for (idx = 0; idx < stall_gp_kthread + 2; idx++) {
1719			if (kthread_should_stop())
1720				break;
1721			schedule_timeout_uninterruptible(HZ);
1722		}
1723	}
1724	if (!kthread_should_stop() && stall_cpu > 0) {
1725		VERBOSE_TOROUT_STRING("rcu_torture_stall begin CPU stall");
1726		stop_at = ktime_get_seconds() + stall_cpu;
1727		/* RCU CPU stall is expected behavior in following code. */
1728		idx = cur_ops->readlock();
1729		if (stall_cpu_irqsoff)
1730			local_irq_disable();
1731		else if (!stall_cpu_block)
1732			preempt_disable();
1733		pr_alert("rcu_torture_stall start on CPU %d.\n",
1734			 raw_smp_processor_id());
1735		while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(),
1736				    stop_at))
1737			if (stall_cpu_block)
 
 
 
1738				schedule_timeout_uninterruptible(HZ);
1739		if (stall_cpu_irqsoff)
 
 
 
 
1740			local_irq_enable();
1741		else if (!stall_cpu_block)
1742			preempt_enable();
1743		cur_ops->readunlock(idx);
1744	}
1745	pr_alert("rcu_torture_stall end.\n");
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1746	torture_shutdown_absorb("rcu_torture_stall");
1747	while (!kthread_should_stop())
1748		schedule_timeout_interruptible(10 * HZ);
1749	return 0;
1750}
1751
1752/* Spawn CPU-stall kthread, if stall_cpu specified. */
1753static int __init rcu_torture_stall_init(void)
1754{
1755	if (stall_cpu <= 0 && stall_gp_kthread <= 0)
1756		return 0;
1757	return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
1758}
1759
1760/* State structure for forward-progress self-propagating RCU callback. */
1761struct fwd_cb_state {
1762	struct rcu_head rh;
1763	int stop;
1764};
1765
1766/*
1767 * Forward-progress self-propagating RCU callback function.  Because
1768 * callbacks run from softirq, this function is an implicit RCU read-side
1769 * critical section.
1770 */
1771static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp)
1772{
1773	struct fwd_cb_state *fcsp = container_of(rhp, struct fwd_cb_state, rh);
1774
1775	if (READ_ONCE(fcsp->stop)) {
1776		WRITE_ONCE(fcsp->stop, 2);
1777		return;
1778	}
1779	cur_ops->call(&fcsp->rh, rcu_torture_fwd_prog_cb);
1780}
1781
1782/* State for continuous-flood RCU callbacks. */
1783struct rcu_fwd_cb {
1784	struct rcu_head rh;
1785	struct rcu_fwd_cb *rfc_next;
1786	struct rcu_fwd *rfc_rfp;
1787	int rfc_gps;
1788};
1789
1790#define MAX_FWD_CB_JIFFIES	(8 * HZ) /* Maximum CB test duration. */
1791#define MIN_FWD_CB_LAUNDERS	3	/* This many CB invocations to count. */
1792#define MIN_FWD_CBS_LAUNDERED	100	/* Number of counted CBs. */
1793#define FWD_CBS_HIST_DIV	10	/* Histogram buckets/second. */
1794#define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV))
1795
1796struct rcu_launder_hist {
1797	long n_launders;
1798	unsigned long launder_gp_seq;
1799};
1800
1801struct rcu_fwd {
1802	spinlock_t rcu_fwd_lock;
1803	struct rcu_fwd_cb *rcu_fwd_cb_head;
1804	struct rcu_fwd_cb **rcu_fwd_cb_tail;
1805	long n_launders_cb;
1806	unsigned long rcu_fwd_startat;
1807	struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST];
1808	unsigned long rcu_launder_gp_seq_start;
 
1809};
1810
 
1811static struct rcu_fwd *rcu_fwds;
 
 
1812static bool rcu_fwd_emergency_stop;
1813
1814static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp)
1815{
1816	unsigned long gps;
1817	unsigned long gps_old;
1818	int i;
1819	int j;
1820
1821	for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--)
1822		if (rfp->n_launders_hist[i].n_launders > 0)
1823			break;
1824	pr_alert("%s: Callback-invocation histogram (duration %lu jiffies):",
1825		 __func__, jiffies - rfp->rcu_fwd_startat);
1826	gps_old = rfp->rcu_launder_gp_seq_start;
1827	for (j = 0; j <= i; j++) {
1828		gps = rfp->n_launders_hist[j].launder_gp_seq;
1829		pr_cont(" %ds/%d: %ld:%ld",
1830			j + 1, FWD_CBS_HIST_DIV,
1831			rfp->n_launders_hist[j].n_launders,
1832			rcutorture_seq_diff(gps, gps_old));
1833		gps_old = gps;
1834	}
1835	pr_cont("\n");
1836}
1837
1838/* Callback function for continuous-flood RCU callbacks. */
1839static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp)
1840{
1841	unsigned long flags;
1842	int i;
1843	struct rcu_fwd_cb *rfcp = container_of(rhp, struct rcu_fwd_cb, rh);
1844	struct rcu_fwd_cb **rfcpp;
1845	struct rcu_fwd *rfp = rfcp->rfc_rfp;
1846
1847	rfcp->rfc_next = NULL;
1848	rfcp->rfc_gps++;
1849	spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
1850	rfcpp = rfp->rcu_fwd_cb_tail;
1851	rfp->rcu_fwd_cb_tail = &rfcp->rfc_next;
1852	WRITE_ONCE(*rfcpp, rfcp);
1853	WRITE_ONCE(rfp->n_launders_cb, rfp->n_launders_cb + 1);
1854	i = ((jiffies - rfp->rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV));
1855	if (i >= ARRAY_SIZE(rfp->n_launders_hist))
1856		i = ARRAY_SIZE(rfp->n_launders_hist) - 1;
1857	rfp->n_launders_hist[i].n_launders++;
1858	rfp->n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq();
1859	spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
1860}
1861
1862// Give the scheduler a chance, even on nohz_full CPUs.
1863static void rcu_torture_fwd_prog_cond_resched(unsigned long iter)
1864{
1865	if (IS_ENABLED(CONFIG_PREEMPTION) && IS_ENABLED(CONFIG_NO_HZ_FULL)) {
1866		// Real call_rcu() floods hit userspace, so emulate that.
1867		if (need_resched() || (iter & 0xfff))
1868			schedule();
1869		return;
1870	}
1871	// No userspace emulation: CB invocation throttles call_rcu()
1872	cond_resched();
1873}
1874
1875/*
1876 * Free all callbacks on the rcu_fwd_cb_head list, either because the
1877 * test is over or because we hit an OOM event.
1878 */
1879static unsigned long rcu_torture_fwd_prog_cbfree(struct rcu_fwd *rfp)
1880{
1881	unsigned long flags;
1882	unsigned long freed = 0;
1883	struct rcu_fwd_cb *rfcp;
1884
1885	for (;;) {
1886		spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
1887		rfcp = rfp->rcu_fwd_cb_head;
1888		if (!rfcp) {
1889			spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
1890			break;
1891		}
1892		rfp->rcu_fwd_cb_head = rfcp->rfc_next;
1893		if (!rfp->rcu_fwd_cb_head)
1894			rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head;
1895		spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
1896		kfree(rfcp);
1897		freed++;
1898		rcu_torture_fwd_prog_cond_resched(freed);
1899		if (tick_nohz_full_enabled()) {
1900			local_irq_save(flags);
1901			rcu_momentary_dyntick_idle();
1902			local_irq_restore(flags);
1903		}
1904	}
1905	return freed;
1906}
1907
1908/* Carry out need_resched()/cond_resched() forward-progress testing. */
1909static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp,
1910				    int *tested, int *tested_tries)
1911{
1912	unsigned long cver;
1913	unsigned long dur;
1914	struct fwd_cb_state fcs;
1915	unsigned long gps;
1916	int idx;
1917	int sd;
1918	int sd4;
1919	bool selfpropcb = false;
1920	unsigned long stopat;
1921	static DEFINE_TORTURE_RANDOM(trs);
1922
1923	if  (cur_ops->call && cur_ops->sync && cur_ops->cb_barrier) {
 
 
 
1924		init_rcu_head_on_stack(&fcs.rh);
1925		selfpropcb = true;
1926	}
1927
1928	/* Tight loop containing cond_resched(). */
1929	WRITE_ONCE(rcu_fwd_cb_nodelay, true);
1930	cur_ops->sync(); /* Later readers see above write. */
1931	if  (selfpropcb) {
1932		WRITE_ONCE(fcs.stop, 0);
1933		cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb);
1934	}
1935	cver = READ_ONCE(rcu_torture_current_version);
1936	gps = cur_ops->get_gp_seq();
1937	sd = cur_ops->stall_dur() + 1;
1938	sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div;
1939	dur = sd4 + torture_random(&trs) % (sd - sd4);
1940	WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
1941	stopat = rfp->rcu_fwd_startat + dur;
1942	while (time_before(jiffies, stopat) &&
1943	       !shutdown_time_arrived() &&
1944	       !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
1945		idx = cur_ops->readlock();
1946		udelay(10);
1947		cur_ops->readunlock(idx);
1948		if (!fwd_progress_need_resched || need_resched())
1949			cond_resched();
1950	}
1951	(*tested_tries)++;
1952	if (!time_before(jiffies, stopat) &&
1953	    !shutdown_time_arrived() &&
1954	    !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
1955		(*tested)++;
1956		cver = READ_ONCE(rcu_torture_current_version) - cver;
1957		gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
1958		WARN_ON(!cver && gps < 2);
1959		pr_alert("%s: Duration %ld cver %ld gps %ld\n", __func__, dur, cver, gps);
 
1960	}
1961	if (selfpropcb) {
1962		WRITE_ONCE(fcs.stop, 1);
1963		cur_ops->sync(); /* Wait for running CB to complete. */
 
1964		cur_ops->cb_barrier(); /* Wait for queued callbacks. */
1965	}
1966
1967	if (selfpropcb) {
1968		WARN_ON(READ_ONCE(fcs.stop) != 2);
1969		destroy_rcu_head_on_stack(&fcs.rh);
1970	}
1971	schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */
1972	WRITE_ONCE(rcu_fwd_cb_nodelay, false);
1973}
1974
1975/* Carry out call_rcu() forward-progress testing. */
1976static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp)
1977{
1978	unsigned long cver;
1979	unsigned long flags;
1980	unsigned long gps;
1981	int i;
1982	long n_launders;
1983	long n_launders_cb_snap;
1984	long n_launders_sa;
1985	long n_max_cbs;
1986	long n_max_gps;
1987	struct rcu_fwd_cb *rfcp;
1988	struct rcu_fwd_cb *rfcpn;
1989	unsigned long stopat;
1990	unsigned long stoppedat;
1991
 
1992	if (READ_ONCE(rcu_fwd_emergency_stop))
1993		return; /* Get out of the way quickly, no GP wait! */
1994	if (!cur_ops->call)
1995		return; /* Can't do call_rcu() fwd prog without ->call. */
1996
1997	/* Loop continuously posting RCU callbacks. */
1998	WRITE_ONCE(rcu_fwd_cb_nodelay, true);
1999	cur_ops->sync(); /* Later readers see above write. */
2000	WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
2001	stopat = rfp->rcu_fwd_startat + MAX_FWD_CB_JIFFIES;
2002	n_launders = 0;
2003	rfp->n_launders_cb = 0; // Hoist initialization for multi-kthread
2004	n_launders_sa = 0;
2005	n_max_cbs = 0;
2006	n_max_gps = 0;
2007	for (i = 0; i < ARRAY_SIZE(rfp->n_launders_hist); i++)
2008		rfp->n_launders_hist[i].n_launders = 0;
2009	cver = READ_ONCE(rcu_torture_current_version);
2010	gps = cur_ops->get_gp_seq();
2011	rfp->rcu_launder_gp_seq_start = gps;
2012	tick_dep_set_task(current, TICK_DEP_BIT_RCU);
2013	while (time_before(jiffies, stopat) &&
2014	       !shutdown_time_arrived() &&
2015	       !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
2016		rfcp = READ_ONCE(rfp->rcu_fwd_cb_head);
2017		rfcpn = NULL;
2018		if (rfcp)
2019			rfcpn = READ_ONCE(rfcp->rfc_next);
2020		if (rfcpn) {
2021			if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS &&
2022			    ++n_max_gps >= MIN_FWD_CBS_LAUNDERED)
2023				break;
2024			rfp->rcu_fwd_cb_head = rfcpn;
2025			n_launders++;
2026			n_launders_sa++;
2027		} else {
2028			rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL);
2029			if (WARN_ON_ONCE(!rfcp)) {
2030				schedule_timeout_interruptible(1);
2031				continue;
2032			}
2033			n_max_cbs++;
2034			n_launders_sa = 0;
2035			rfcp->rfc_gps = 0;
2036			rfcp->rfc_rfp = rfp;
 
 
2037		}
2038		cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr);
 
2039		rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs);
2040		if (tick_nohz_full_enabled()) {
2041			local_irq_save(flags);
2042			rcu_momentary_dyntick_idle();
2043			local_irq_restore(flags);
2044		}
2045	}
2046	stoppedat = jiffies;
2047	n_launders_cb_snap = READ_ONCE(rfp->n_launders_cb);
2048	cver = READ_ONCE(rcu_torture_current_version) - cver;
2049	gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
 
2050	cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */
2051	(void)rcu_torture_fwd_prog_cbfree(rfp);
2052
2053	if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) &&
2054	    !shutdown_time_arrived()) {
2055		WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED);
2056		pr_alert("%s Duration %lu barrier: %lu pending %ld n_launders: %ld n_launders_sa: %ld n_max_gps: %ld n_max_cbs: %ld cver %ld gps %ld\n",
 
2057			 __func__,
2058			 stoppedat - rfp->rcu_fwd_startat, jiffies - stoppedat,
2059			 n_launders + n_max_cbs - n_launders_cb_snap,
2060			 n_launders, n_launders_sa,
2061			 n_max_gps, n_max_cbs, cver, gps);
 
 
2062		rcu_torture_fwd_cb_hist(rfp);
 
2063	}
2064	schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */
2065	tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
2066	WRITE_ONCE(rcu_fwd_cb_nodelay, false);
2067}
2068
2069
2070/*
2071 * OOM notifier, but this only prints diagnostic information for the
2072 * current forward-progress test.
2073 */
2074static int rcutorture_oom_notify(struct notifier_block *self,
2075				 unsigned long notused, void *nfreed)
2076{
2077	struct rcu_fwd *rfp = rcu_fwds;
 
 
2078
 
 
 
 
 
 
2079	WARN(1, "%s invoked upon OOM during forward-progress testing.\n",
2080	     __func__);
2081	rcu_torture_fwd_cb_hist(rfp);
2082	rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp->rcu_fwd_startat)) / 2);
 
 
2083	WRITE_ONCE(rcu_fwd_emergency_stop, true);
2084	smp_mb(); /* Emergency stop before free and wait to avoid hangs. */
2085	pr_info("%s: Freed %lu RCU callbacks.\n",
2086		__func__, rcu_torture_fwd_prog_cbfree(rfp));
2087	rcu_barrier();
2088	pr_info("%s: Freed %lu RCU callbacks.\n",
2089		__func__, rcu_torture_fwd_prog_cbfree(rfp));
2090	rcu_barrier();
2091	pr_info("%s: Freed %lu RCU callbacks.\n",
2092		__func__, rcu_torture_fwd_prog_cbfree(rfp));
 
 
 
 
 
 
2093	smp_mb(); /* Frees before return to avoid redoing OOM. */
2094	(*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */
2095	pr_info("%s returning after OOM processing.\n", __func__);
 
2096	return NOTIFY_OK;
2097}
2098
2099static struct notifier_block rcutorture_oom_nb = {
2100	.notifier_call = rcutorture_oom_notify
2101};
2102
2103/* Carry out grace-period forward-progress testing. */
2104static int rcu_torture_fwd_prog(void *args)
2105{
 
 
 
 
2106	struct rcu_fwd *rfp = args;
2107	int tested = 0;
2108	int tested_tries = 0;
2109
2110	VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started");
2111	rcu_bind_current_to_nocb();
2112	if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST))
2113		set_user_nice(current, MAX_NICE);
2114	do {
2115		schedule_timeout_interruptible(fwd_progress_holdoff * HZ);
2116		WRITE_ONCE(rcu_fwd_emergency_stop, false);
2117		register_oom_notifier(&rcutorture_oom_nb);
2118		if (!IS_ENABLED(CONFIG_TINY_RCU) ||
2119		    rcu_inkernel_boot_has_ended())
2120			rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries);
2121		if (rcu_inkernel_boot_has_ended())
 
 
 
 
 
 
 
 
 
2122			rcu_torture_fwd_prog_cr(rfp);
2123		unregister_oom_notifier(&rcutorture_oom_nb);
 
 
 
 
2124
2125		/* Avoid slow periods, better to test when busy. */
2126		stutter_wait("rcu_torture_fwd_prog");
 
2127	} while (!torture_must_stop());
2128	/* Short runs might not contain a valid forward-progress attempt. */
2129	WARN_ON(!tested && tested_tries >= 5);
2130	pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries);
 
 
2131	torture_kthread_stopping("rcu_torture_fwd_prog");
2132	return 0;
2133}
2134
2135/* If forward-progress checking is requested and feasible, spawn the thread. */
2136static int __init rcu_torture_fwd_prog_init(void)
2137{
 
 
2138	struct rcu_fwd *rfp;
2139
2140	if (!fwd_progress)
2141		return 0; /* Not requested, so don't do it. */
2142	if (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0 ||
 
 
 
 
 
 
 
2143	    cur_ops == &rcu_busted_ops) {
2144		VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test");
 
2145		return 0;
2146	}
2147	if (stall_cpu > 0) {
2148		VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall testing");
2149		if (IS_MODULE(CONFIG_RCU_TORTURE_TESTS))
 
2150			return -EINVAL; /* In module, can fail back to user. */
2151		WARN_ON(1); /* Make sure rcutorture notices conflict. */
2152		return 0;
2153	}
2154	if (fwd_progress_holdoff <= 0)
2155		fwd_progress_holdoff = 1;
2156	if (fwd_progress_div <= 0)
2157		fwd_progress_div = 4;
2158	rfp = kzalloc(sizeof(*rfp), GFP_KERNEL);
2159	if (!rfp)
 
 
 
 
 
2160		return -ENOMEM;
2161	spin_lock_init(&rfp->rcu_fwd_lock);
2162	rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head;
2163	return torture_create_kthread(rcu_torture_fwd_prog, rfp, fwd_prog_task);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2164}
2165
2166/* Callback function for RCU barrier testing. */
2167static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
2168{
2169	atomic_inc(&barrier_cbs_invoked);
2170}
2171
2172/* IPI handler to get callback posted on desired CPU, if online. */
2173static void rcu_torture_barrier1cb(void *rcu_void)
2174{
2175	struct rcu_head *rhp = rcu_void;
2176
2177	cur_ops->call(rhp, rcu_torture_barrier_cbf);
 
2178}
2179
2180/* kthread function to register callbacks used to test RCU barriers. */
2181static int rcu_torture_barrier_cbs(void *arg)
2182{
2183	long myid = (long)arg;
2184	bool lastphase = false;
2185	bool newphase;
2186	struct rcu_head rcu;
2187
2188	init_rcu_head_on_stack(&rcu);
2189	VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
2190	set_user_nice(current, MAX_NICE);
2191	do {
2192		wait_event(barrier_cbs_wq[myid],
2193			   (newphase =
2194			    smp_load_acquire(&barrier_phase)) != lastphase ||
2195			   torture_must_stop());
2196		lastphase = newphase;
2197		if (torture_must_stop())
2198			break;
2199		/*
2200		 * The above smp_load_acquire() ensures barrier_phase load
2201		 * is ordered before the following ->call().
2202		 */
2203		if (smp_call_function_single(myid, rcu_torture_barrier1cb,
2204					     &rcu, 1)) {
2205			// IPI failed, so use direct call from current CPU.
2206			cur_ops->call(&rcu, rcu_torture_barrier_cbf);
2207		}
2208		if (atomic_dec_and_test(&barrier_cbs_count))
2209			wake_up(&barrier_wq);
2210	} while (!torture_must_stop());
2211	if (cur_ops->cb_barrier != NULL)
2212		cur_ops->cb_barrier();
2213	destroy_rcu_head_on_stack(&rcu);
2214	torture_kthread_stopping("rcu_torture_barrier_cbs");
2215	return 0;
2216}
2217
2218/* kthread function to drive and coordinate RCU barrier testing. */
2219static int rcu_torture_barrier(void *arg)
2220{
2221	int i;
2222
2223	VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
2224	do {
2225		atomic_set(&barrier_cbs_invoked, 0);
2226		atomic_set(&barrier_cbs_count, n_barrier_cbs);
2227		/* Ensure barrier_phase ordered after prior assignments. */
2228		smp_store_release(&barrier_phase, !barrier_phase);
2229		for (i = 0; i < n_barrier_cbs; i++)
2230			wake_up(&barrier_cbs_wq[i]);
2231		wait_event(barrier_wq,
2232			   atomic_read(&barrier_cbs_count) == 0 ||
2233			   torture_must_stop());
2234		if (torture_must_stop())
2235			break;
2236		n_barrier_attempts++;
2237		cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
2238		if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
2239			n_rcu_torture_barrier_error++;
2240			pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
2241			       atomic_read(&barrier_cbs_invoked),
2242			       n_barrier_cbs);
2243			WARN_ON(1);
2244			// Wait manually for the remaining callbacks
2245			i = 0;
2246			do {
2247				if (WARN_ON(i++ > HZ))
2248					i = INT_MIN;
2249				schedule_timeout_interruptible(1);
2250				cur_ops->cb_barrier();
2251			} while (atomic_read(&barrier_cbs_invoked) !=
2252				 n_barrier_cbs &&
2253				 !torture_must_stop());
2254			smp_mb(); // Can't trust ordering if broken.
2255			if (!torture_must_stop())
2256				pr_err("Recovered: barrier_cbs_invoked = %d\n",
2257				       atomic_read(&barrier_cbs_invoked));
2258		} else {
2259			n_barrier_successes++;
2260		}
2261		schedule_timeout_interruptible(HZ / 10);
2262	} while (!torture_must_stop());
2263	torture_kthread_stopping("rcu_torture_barrier");
2264	return 0;
2265}
2266
2267/* Initialize RCU barrier testing. */
2268static int rcu_torture_barrier_init(void)
2269{
2270	int i;
2271	int ret;
2272
2273	if (n_barrier_cbs <= 0)
2274		return 0;
2275	if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
2276		pr_alert("%s" TORTURE_FLAG
2277			 " Call or barrier ops missing for %s,\n",
2278			 torture_type, cur_ops->name);
2279		pr_alert("%s" TORTURE_FLAG
2280			 " RCU barrier testing omitted from run.\n",
2281			 torture_type);
2282		return 0;
2283	}
2284	atomic_set(&barrier_cbs_count, 0);
2285	atomic_set(&barrier_cbs_invoked, 0);
2286	barrier_cbs_tasks =
2287		kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]),
2288			GFP_KERNEL);
2289	barrier_cbs_wq =
2290		kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL);
2291	if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
2292		return -ENOMEM;
2293	for (i = 0; i < n_barrier_cbs; i++) {
2294		init_waitqueue_head(&barrier_cbs_wq[i]);
2295		ret = torture_create_kthread(rcu_torture_barrier_cbs,
2296					     (void *)(long)i,
2297					     barrier_cbs_tasks[i]);
2298		if (ret)
2299			return ret;
2300	}
2301	return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
2302}
2303
2304/* Clean up after RCU barrier testing. */
2305static void rcu_torture_barrier_cleanup(void)
2306{
2307	int i;
2308
2309	torture_stop_kthread(rcu_torture_barrier, barrier_task);
2310	if (barrier_cbs_tasks != NULL) {
2311		for (i = 0; i < n_barrier_cbs; i++)
2312			torture_stop_kthread(rcu_torture_barrier_cbs,
2313					     barrier_cbs_tasks[i]);
2314		kfree(barrier_cbs_tasks);
2315		barrier_cbs_tasks = NULL;
2316	}
2317	if (barrier_cbs_wq != NULL) {
2318		kfree(barrier_cbs_wq);
2319		barrier_cbs_wq = NULL;
2320	}
2321}
2322
2323static bool rcu_torture_can_boost(void)
2324{
2325	static int boost_warn_once;
2326	int prio;
2327
2328	if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2)
2329		return false;
 
 
2330
2331	prio = rcu_get_gp_kthreads_prio();
2332	if (!prio)
2333		return false;
2334
2335	if (prio < 2) {
2336		if (boost_warn_once  == 1)
2337			return false;
2338
2339		pr_alert("%s: WARN: RCU kthread priority too low to test boosting.  Skipping RCU boost test. Try passing rcutree.kthread_prio > 1 on the kernel command line.\n", KBUILD_MODNAME);
2340		boost_warn_once = 1;
2341		return false;
2342	}
2343
2344	return true;
2345}
2346
2347static bool read_exit_child_stop;
2348static bool read_exit_child_stopped;
2349static wait_queue_head_t read_exit_wq;
2350
2351// Child kthread which just does an rcutorture reader and exits.
2352static int rcu_torture_read_exit_child(void *trsp_in)
2353{
2354	struct torture_random_state *trsp = trsp_in;
2355
2356	set_user_nice(current, MAX_NICE);
2357	// Minimize time between reading and exiting.
2358	while (!kthread_should_stop())
2359		schedule_timeout_uninterruptible(1);
2360	(void)rcu_torture_one_read(trsp);
2361	return 0;
2362}
2363
2364// Parent kthread which creates and destroys read-exit child kthreads.
2365static int rcu_torture_read_exit(void *unused)
2366{
2367	int count = 0;
2368	bool errexit = false;
2369	int i;
2370	struct task_struct *tsp;
2371	DEFINE_TORTURE_RANDOM(trs);
2372
2373	// Allocate and initialize.
2374	set_user_nice(current, MAX_NICE);
2375	VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of test");
2376
2377	// Each pass through this loop does one read-exit episode.
2378	do {
2379		if (++count > read_exit_burst) {
2380			VERBOSE_TOROUT_STRING("rcu_torture_read_exit: End of episode");
2381			rcu_barrier(); // Wait for task_struct free, avoid OOM.
2382			for (i = 0; i < read_exit_delay; i++) {
2383				schedule_timeout_uninterruptible(HZ);
2384				if (READ_ONCE(read_exit_child_stop))
2385					break;
 
 
 
 
 
2386			}
2387			if (!READ_ONCE(read_exit_child_stop))
2388				VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of episode");
2389			count = 0;
2390		}
2391		if (READ_ONCE(read_exit_child_stop))
2392			break;
2393		// Spawn child.
2394		tsp = kthread_run(rcu_torture_read_exit_child,
2395				     &trs, "%s",
2396				     "rcu_torture_read_exit_child");
2397		if (IS_ERR(tsp)) {
2398			VERBOSE_TOROUT_ERRSTRING("out of memory");
2399			errexit = true;
2400			tsp = NULL;
2401			break;
2402		}
2403		cond_resched();
2404		kthread_stop(tsp);
2405		n_read_exits ++;
2406		stutter_wait("rcu_torture_read_exit");
 
2407	} while (!errexit && !READ_ONCE(read_exit_child_stop));
2408
2409	// Clean up and exit.
2410	smp_store_release(&read_exit_child_stopped, true); // After reaping.
2411	smp_mb(); // Store before wakeup.
2412	wake_up(&read_exit_wq);
2413	while (!torture_must_stop())
2414		schedule_timeout_uninterruptible(1);
2415	torture_kthread_stopping("rcu_torture_read_exit");
2416	return 0;
2417}
2418
2419static int rcu_torture_read_exit_init(void)
2420{
2421	if (read_exit_burst <= 0)
2422		return -EINVAL;
2423	init_waitqueue_head(&read_exit_wq);
2424	read_exit_child_stop = false;
2425	read_exit_child_stopped = false;
2426	return torture_create_kthread(rcu_torture_read_exit, NULL,
2427				      read_exit_task);
2428}
2429
2430static void rcu_torture_read_exit_cleanup(void)
2431{
2432	if (!read_exit_task)
2433		return;
2434	WRITE_ONCE(read_exit_child_stop, true);
2435	smp_mb(); // Above write before wait.
2436	wait_event(read_exit_wq, smp_load_acquire(&read_exit_child_stopped));
2437	torture_stop_kthread(rcutorture_read_exit, read_exit_task);
2438}
2439
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2440static enum cpuhp_state rcutor_hp;
2441
2442static void
2443rcu_torture_cleanup(void)
2444{
2445	int firsttime;
2446	int flags = 0;
2447	unsigned long gp_seq = 0;
2448	int i;
2449
2450	if (torture_cleanup_begin()) {
2451		if (cur_ops->cb_barrier != NULL)
 
2452			cur_ops->cb_barrier();
 
 
 
2453		return;
2454	}
2455	if (!cur_ops) {
2456		torture_cleanup_end();
2457		return;
2458	}
2459
2460	show_rcu_gp_kthreads();
 
 
 
2461	rcu_torture_read_exit_cleanup();
2462	rcu_torture_barrier_cleanup();
2463	torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_task);
2464	torture_stop_kthread(rcu_torture_stall, stall_task);
2465	torture_stop_kthread(rcu_torture_writer, writer_task);
2466
 
 
 
 
 
 
 
2467	if (reader_tasks) {
2468		for (i = 0; i < nrealreaders; i++)
2469			torture_stop_kthread(rcu_torture_reader,
2470					     reader_tasks[i]);
2471		kfree(reader_tasks);
 
2472	}
 
 
2473
2474	if (fakewriter_tasks) {
2475		for (i = 0; i < nfakewriters; i++) {
2476			torture_stop_kthread(rcu_torture_fakewriter,
2477					     fakewriter_tasks[i]);
2478		}
2479		kfree(fakewriter_tasks);
2480		fakewriter_tasks = NULL;
2481	}
2482
2483	rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq);
2484	srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq);
2485	pr_alert("%s:  End-test grace-period state: g%lu f%#x\n",
2486		 cur_ops->name, gp_seq, flags);
 
2487	torture_stop_kthread(rcu_torture_stats, stats_task);
2488	torture_stop_kthread(rcu_torture_fqs, fqs_task);
2489	if (rcu_torture_can_boost())
2490		cpuhp_remove_state(rcutor_hp);
2491
2492	/*
2493	 * Wait for all RCU callbacks to fire, then do torture-type-specific
2494	 * cleanup operations.
2495	 */
2496	if (cur_ops->cb_barrier != NULL)
 
2497		cur_ops->cb_barrier();
 
2498	if (cur_ops->cleanup != NULL)
2499		cur_ops->cleanup();
2500
 
 
2501	rcu_torture_stats_print();  /* -After- the stats thread is stopped! */
2502
2503	if (err_segs_recorded) {
2504		pr_alert("Failure/close-call rcutorture reader segments:\n");
2505		if (rt_read_nsegs == 0)
2506			pr_alert("\t: No segments recorded!!!\n");
2507		firsttime = 1;
2508		for (i = 0; i < rt_read_nsegs; i++) {
2509			pr_alert("\t%d: %#x ", i, err_segs[i].rt_readstate);
2510			if (err_segs[i].rt_delay_jiffies != 0) {
2511				pr_cont("%s%ldjiffies", firsttime ? "" : "+",
2512					err_segs[i].rt_delay_jiffies);
2513				firsttime = 0;
2514			}
2515			if (err_segs[i].rt_delay_ms != 0) {
2516				pr_cont("%s%ldms", firsttime ? "" : "+",
2517					err_segs[i].rt_delay_ms);
2518				firsttime = 0;
2519			}
2520			if (err_segs[i].rt_delay_us != 0) {
2521				pr_cont("%s%ldus", firsttime ? "" : "+",
2522					err_segs[i].rt_delay_us);
2523				firsttime = 0;
2524			}
2525			pr_cont("%s\n",
2526				err_segs[i].rt_preempted ? "preempted" : "");
2527
2528		}
2529	}
2530	if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
2531		rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
2532	else if (torture_onoff_failures())
2533		rcu_torture_print_module_parms(cur_ops,
2534					       "End of test: RCU_HOTPLUG");
2535	else
2536		rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
2537	torture_cleanup_end();
 
 
2538}
2539
2540#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
2541static void rcu_torture_leak_cb(struct rcu_head *rhp)
2542{
2543}
2544
2545static void rcu_torture_err_cb(struct rcu_head *rhp)
2546{
2547	/*
2548	 * This -might- happen due to race conditions, but is unlikely.
2549	 * The scenario that leads to this happening is that the
2550	 * first of the pair of duplicate callbacks is queued,
2551	 * someone else starts a grace period that includes that
2552	 * callback, then the second of the pair must wait for the
2553	 * next grace period.  Unlikely, but can happen.  If it
2554	 * does happen, the debug-objects subsystem won't have splatted.
2555	 */
2556	pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME);
2557}
2558#endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
2559
2560/*
2561 * Verify that double-free causes debug-objects to complain, but only
2562 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y.  Otherwise, say that the test
2563 * cannot be carried out.
2564 */
2565static void rcu_test_debug_objects(void)
2566{
2567#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
2568	struct rcu_head rh1;
2569	struct rcu_head rh2;
 
 
 
 
 
 
 
 
 
 
 
 
 
2570
2571	init_rcu_head_on_stack(&rh1);
2572	init_rcu_head_on_stack(&rh2);
2573	pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME);
2574
2575	/* Try to queue the rh2 pair of callbacks for the same grace period. */
2576	preempt_disable(); /* Prevent preemption from interrupting test. */
2577	rcu_read_lock(); /* Make it impossible to finish a grace period. */
2578	call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
2579	local_irq_disable(); /* Make it harder to start a new grace period. */
2580	call_rcu(&rh2, rcu_torture_leak_cb);
2581	call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
2582	local_irq_enable();
2583	rcu_read_unlock();
2584	preempt_enable();
2585
2586	/* Wait for them all to get done so we can safely return. */
2587	rcu_barrier();
2588	pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME);
2589	destroy_rcu_head_on_stack(&rh1);
2590	destroy_rcu_head_on_stack(&rh2);
2591#else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
2592	pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME);
2593#endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
2594}
2595
2596static void rcutorture_sync(void)
2597{
2598	static unsigned long n;
2599
2600	if (cur_ops->sync && !(++n & 0xfff))
2601		cur_ops->sync();
2602}
2603
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2604static int __init
2605rcu_torture_init(void)
2606{
2607	long i;
2608	int cpu;
2609	int firsterr = 0;
 
 
2610	static struct rcu_torture_ops *torture_ops[] = {
2611		&rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops,
2612		&busted_srcud_ops, &tasks_ops, &tasks_rude_ops,
2613		&tasks_tracing_ops, &trivial_ops,
2614	};
2615
2616	if (!torture_init_begin(torture_type, verbose))
2617		return -EBUSY;
2618
2619	/* Process args and tell the world that the torturer is on the job. */
2620	for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
2621		cur_ops = torture_ops[i];
2622		if (strcmp(torture_type, cur_ops->name) == 0)
2623			break;
2624	}
2625	if (i == ARRAY_SIZE(torture_ops)) {
2626		pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
2627			 torture_type);
2628		pr_alert("rcu-torture types:");
2629		for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
2630			pr_cont(" %s", torture_ops[i]->name);
2631		pr_cont("\n");
2632		WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST));
2633		firsterr = -EINVAL;
2634		cur_ops = NULL;
2635		goto unwind;
2636	}
2637	if (cur_ops->fqs == NULL && fqs_duration != 0) {
2638		pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
2639		fqs_duration = 0;
2640	}
 
 
 
 
 
 
2641	if (cur_ops->init)
2642		cur_ops->init();
2643
 
 
2644	if (nreaders >= 0) {
2645		nrealreaders = nreaders;
2646	} else {
2647		nrealreaders = num_online_cpus() - 2 - nreaders;
2648		if (nrealreaders <= 0)
2649			nrealreaders = 1;
2650	}
2651	rcu_torture_print_module_parms(cur_ops, "Start of test");
 
 
 
 
 
2652
2653	/* Set up the freelist. */
2654
2655	INIT_LIST_HEAD(&rcu_torture_freelist);
2656	for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
2657		rcu_tortures[i].rtort_mbtest = 0;
2658		list_add_tail(&rcu_tortures[i].rtort_free,
2659			      &rcu_torture_freelist);
2660	}
2661
2662	/* Initialize the statistics so that each run gets its own numbers. */
2663
2664	rcu_torture_current = NULL;
2665	rcu_torture_current_version = 0;
2666	atomic_set(&n_rcu_torture_alloc, 0);
2667	atomic_set(&n_rcu_torture_alloc_fail, 0);
2668	atomic_set(&n_rcu_torture_free, 0);
2669	atomic_set(&n_rcu_torture_mberror, 0);
 
 
2670	atomic_set(&n_rcu_torture_error, 0);
2671	n_rcu_torture_barrier_error = 0;
2672	n_rcu_torture_boost_ktrerror = 0;
2673	n_rcu_torture_boost_rterror = 0;
2674	n_rcu_torture_boost_failure = 0;
2675	n_rcu_torture_boosts = 0;
2676	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
2677		atomic_set(&rcu_torture_wcount[i], 0);
2678	for_each_possible_cpu(cpu) {
2679		for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
2680			per_cpu(rcu_torture_count, cpu)[i] = 0;
2681			per_cpu(rcu_torture_batch, cpu)[i] = 0;
2682		}
2683	}
2684	err_segs_recorded = 0;
2685	rt_read_nsegs = 0;
2686
2687	/* Start up the kthreads. */
2688
 
2689	firsterr = torture_create_kthread(rcu_torture_writer, NULL,
2690					  writer_task);
2691	if (firsterr)
2692		goto unwind;
2693	if (nfakewriters > 0) {
2694		fakewriter_tasks = kcalloc(nfakewriters,
2695					   sizeof(fakewriter_tasks[0]),
2696					   GFP_KERNEL);
2697		if (fakewriter_tasks == NULL) {
2698			VERBOSE_TOROUT_ERRSTRING("out of memory");
2699			firsterr = -ENOMEM;
2700			goto unwind;
2701		}
2702	}
2703	for (i = 0; i < nfakewriters; i++) {
2704		firsterr = torture_create_kthread(rcu_torture_fakewriter,
2705						  NULL, fakewriter_tasks[i]);
2706		if (firsterr)
2707			goto unwind;
2708	}
2709	reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
2710			       GFP_KERNEL);
2711	if (reader_tasks == NULL) {
2712		VERBOSE_TOROUT_ERRSTRING("out of memory");
 
 
2713		firsterr = -ENOMEM;
2714		goto unwind;
2715	}
2716	for (i = 0; i < nrealreaders; i++) {
 
2717		firsterr = torture_create_kthread(rcu_torture_reader, (void *)i,
2718						  reader_tasks[i]);
2719		if (firsterr)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2720			goto unwind;
2721	}
2722	if (stat_interval > 0) {
2723		firsterr = torture_create_kthread(rcu_torture_stats, NULL,
2724						  stats_task);
2725		if (firsterr)
2726			goto unwind;
2727	}
2728	if (test_no_idle_hz && shuffle_interval > 0) {
2729		firsterr = torture_shuffle_init(shuffle_interval * HZ);
2730		if (firsterr)
2731			goto unwind;
2732	}
2733	if (stutter < 0)
2734		stutter = 0;
2735	if (stutter) {
2736		int t;
2737
2738		t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ;
2739		firsterr = torture_stutter_init(stutter * HZ, t);
2740		if (firsterr)
2741			goto unwind;
2742	}
2743	if (fqs_duration < 0)
2744		fqs_duration = 0;
2745	if (fqs_duration) {
 
 
2746		/* Create the fqs thread */
2747		firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
2748						  fqs_task);
2749		if (firsterr)
2750			goto unwind;
2751	}
2752	if (test_boost_interval < 1)
2753		test_boost_interval = 1;
2754	if (test_boost_duration < 2)
2755		test_boost_duration = 2;
2756	if (rcu_torture_can_boost()) {
2757
2758		boost_starttime = jiffies + test_boost_interval * HZ;
2759
2760		firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE",
2761					     rcutorture_booster_init,
2762					     rcutorture_booster_cleanup);
2763		if (firsterr < 0)
2764			goto unwind;
2765		rcutor_hp = firsterr;
 
 
2766	}
2767	shutdown_jiffies = jiffies + shutdown_secs * HZ;
2768	firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
2769	if (firsterr)
2770		goto unwind;
2771	firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval,
2772				      rcutorture_sync);
2773	if (firsterr)
2774		goto unwind;
2775	firsterr = rcu_torture_stall_init();
2776	if (firsterr)
2777		goto unwind;
2778	firsterr = rcu_torture_fwd_prog_init();
2779	if (firsterr)
2780		goto unwind;
2781	firsterr = rcu_torture_barrier_init();
2782	if (firsterr)
2783		goto unwind;
2784	firsterr = rcu_torture_read_exit_init();
2785	if (firsterr)
2786		goto unwind;
2787	if (object_debug)
2788		rcu_test_debug_objects();
2789	torture_init_end();
 
 
2790	return 0;
2791
2792unwind:
2793	torture_init_end();
2794	rcu_torture_cleanup();
 
 
 
 
2795	return firsterr;
2796}
2797
2798module_init(rcu_torture_init);
2799module_exit(rcu_torture_cleanup);