rcutorture.c 53.9 KB
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/*
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 * Read-Copy Update module-based torture test facility
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 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
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 * along with this program; if not, you can access it online at
 * http://www.gnu.org/licenses/gpl-2.0.html.
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 *
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 * Copyright (C) IBM Corporation, 2005, 2006
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 *
 * Authors: Paul E. McKenney <paulmck@us.ibm.com>
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 *	  Josh Triplett <josh@joshtriplett.org>
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 *
 * See also:  Documentation/RCU/torture.txt
 */
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kthread.h>
#include <linux/err.h>
#include <linux/spinlock.h>
#include <linux/smp.h>
#include <linux/rcupdate.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
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#include <linux/atomic.h>
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#include <linux/bitops.h>
#include <linux/completion.h>
#include <linux/moduleparam.h>
#include <linux/percpu.h>
#include <linux/notifier.h>
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#include <linux/reboot.h>
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#include <linux/freezer.h>
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#include <linux/cpu.h>
#include <linux/delay.h>
#include <linux/stat.h>
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#include <linux/srcu.h>
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#include <linux/slab.h>
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#include <linux/trace_clock.h>
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#include <asm/byteorder.h>
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#include <linux/torture.h>
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#include <linux/vmalloc.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
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torture_param(int, cbflood_inter_holdoff, HZ,
	      "Holdoff between floods (jiffies)");
torture_param(int, cbflood_intra_holdoff, 1,
	      "Holdoff between bursts (jiffies)");
torture_param(int, cbflood_n_burst, 3, "# bursts in flood, zero to disable");
torture_param(int, cbflood_n_per_burst, 20000,
	      "# callbacks per burst in flood");
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torture_param(int, fqs_duration, 0,
	      "Duration of fqs bursts (us), 0 to disable");
torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
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torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
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torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
torture_param(bool, gp_normal, false,
	     "Use normal (non-expedited) GP wait primitives");
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torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
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torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
torture_param(int, n_barrier_cbs, 0,
	     "# of callbacks/kthreads for barrier testing");
torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
torture_param(int, nreaders, -1, "Number of RCU reader threads");
torture_param(int, object_debug, 0,
	     "Enable debug-object double call_rcu() testing");
torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
torture_param(int, onoff_interval, 0,
	     "Time between CPU hotplugs (s), 0=disable");
torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
torture_param(int, stall_cpu_holdoff, 10,
	     "Time to wait before starting stall (s).");
torture_param(int, stat_interval, 60,
	     "Number of seconds between stats printk()s");
torture_param(int, stutter, 5, "Number of seconds to run/halt test");
torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
torture_param(int, test_boost_duration, 4,
	     "Duration of each boost test, seconds.");
torture_param(int, test_boost_interval, 7,
	     "Interval between boost tests, seconds.");
torture_param(bool, test_no_idle_hz, true,
	     "Test support for tickless idle CPUs");
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torture_param(bool, verbose, true,
	     "Enable verbose debugging printk()s");
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static char *torture_type = "rcu";
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module_param(torture_type, charp, 0444);
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MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, ...)");
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static int nrealreaders;
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static int ncbflooders;
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static struct task_struct *writer_task;
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static struct task_struct **fakewriter_tasks;
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static struct task_struct **reader_tasks;
static struct task_struct *stats_task;
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static struct task_struct **cbflood_task;
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static struct task_struct *fqs_task;
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static struct task_struct *boost_tasks[NR_CPUS];
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static struct task_struct *stall_task;
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static struct task_struct **barrier_cbs_tasks;
static struct task_struct *barrier_task;
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#define RCU_TORTURE_PIPE_LEN 10

struct rcu_torture {
	struct rcu_head rtort_rcu;
	int rtort_pipe_count;
	struct list_head rtort_free;
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	int rtort_mbtest;
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};

static LIST_HEAD(rcu_torture_freelist);
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static struct rcu_torture __rcu *rcu_torture_current;
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static unsigned long rcu_torture_current_version;
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static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
static DEFINE_SPINLOCK(rcu_torture_lock);
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static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1],
		      rcu_torture_count) = { 0 };
static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1],
		      rcu_torture_batch) = { 0 };
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static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
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static atomic_t n_rcu_torture_alloc;
static atomic_t n_rcu_torture_alloc_fail;
static atomic_t n_rcu_torture_free;
static atomic_t n_rcu_torture_mberror;
static atomic_t n_rcu_torture_error;
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static long n_rcu_torture_barrier_error;
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static long n_rcu_torture_boost_ktrerror;
static long n_rcu_torture_boost_rterror;
static long n_rcu_torture_boost_failure;
static long n_rcu_torture_boosts;
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static long n_rcu_torture_timers;
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static long n_barrier_attempts;
static long n_barrier_successes;
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static atomic_long_t n_cbfloods;
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static struct list_head rcu_torture_removed;
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static int rcu_torture_writer_state;
#define RTWS_FIXED_DELAY	0
#define RTWS_DELAY		1
#define RTWS_REPLACE		2
#define RTWS_DEF_FREE		3
#define RTWS_EXP_SYNC		4
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#define RTWS_COND_GET		5
#define RTWS_COND_SYNC		6
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#define RTWS_SYNC		7
#define RTWS_STUTTER		8
#define RTWS_STOPPING		9
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#if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
#define RCUTORTURE_RUNNABLE_INIT 1
#else
#define RCUTORTURE_RUNNABLE_INIT 0
#endif
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static int torture_runnable = RCUTORTURE_RUNNABLE_INIT;
module_param(torture_runnable, int, 0444);
MODULE_PARM_DESC(torture_runnable, "Start rcutorture at boot");
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#if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
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#define rcu_can_boost() 1
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#else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
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#define rcu_can_boost() 0
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#endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
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#ifdef CONFIG_RCU_TRACE
static u64 notrace rcu_trace_clock_local(void)
{
	u64 ts = trace_clock_local();
	unsigned long __maybe_unused ts_rem = do_div(ts, NSEC_PER_USEC);
	return ts;
}
#else /* #ifdef CONFIG_RCU_TRACE */
static u64 notrace rcu_trace_clock_local(void)
{
	return 0ULL;
}
#endif /* #else #ifdef CONFIG_RCU_TRACE */

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static unsigned long boost_starttime;	/* jiffies of next boost test start. */
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static DEFINE_MUTEX(boost_mutex);	/* protect setting boost_starttime */
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					/*  and boost task create/destroy. */
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static atomic_t barrier_cbs_count;	/* Barrier callbacks registered. */
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static bool barrier_phase;		/* Test phase. */
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static atomic_t barrier_cbs_invoked;	/* Barrier callbacks invoked. */
static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
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/*
 * Allocate an element from the rcu_tortures pool.
 */
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static struct rcu_torture *
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rcu_torture_alloc(void)
{
	struct list_head *p;

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	spin_lock_bh(&rcu_torture_lock);
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	if (list_empty(&rcu_torture_freelist)) {
		atomic_inc(&n_rcu_torture_alloc_fail);
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		spin_unlock_bh(&rcu_torture_lock);
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		return NULL;
	}
	atomic_inc(&n_rcu_torture_alloc);
	p = rcu_torture_freelist.next;
	list_del_init(p);
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	spin_unlock_bh(&rcu_torture_lock);
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	return container_of(p, struct rcu_torture, rtort_free);
}

/*
 * Free an element to the rcu_tortures pool.
 */
static void
rcu_torture_free(struct rcu_torture *p)
{
	atomic_inc(&n_rcu_torture_free);
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	spin_lock_bh(&rcu_torture_lock);
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	list_add_tail(&p->rtort_free, &rcu_torture_freelist);
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	spin_unlock_bh(&rcu_torture_lock);
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}

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/*
 * Operations vector for selecting different types of tests.
 */

struct rcu_torture_ops {
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	int ttype;
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	void (*init)(void);
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	void (*cleanup)(void);
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	int (*readlock)(void);
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	void (*read_delay)(struct torture_random_state *rrsp);
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	void (*readunlock)(int idx);
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	unsigned long (*started)(void);
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	unsigned long (*completed)(void);
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	void (*deferred_free)(struct rcu_torture *p);
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	void (*sync)(void);
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	void (*exp_sync)(void);
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	unsigned long (*get_state)(void);
	void (*cond_sync)(unsigned long oldstate);
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	void (*call)(struct rcu_head *head, void (*func)(struct rcu_head *rcu));
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	void (*cb_barrier)(void);
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	void (*fqs)(void);
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	void (*stats)(void);
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	int irq_capable;
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	int can_boost;
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	const char *name;
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};
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static struct rcu_torture_ops *cur_ops;
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/*
 * Definitions for rcu torture testing.
 */

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static int rcu_torture_read_lock(void) __acquires(RCU)
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{
	rcu_read_lock();
	return 0;
}

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static void rcu_read_delay(struct torture_random_state *rrsp)
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{
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	const unsigned long shortdelay_us = 200;
	const unsigned long longdelay_ms = 50;
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	/* We want a short delay sometimes to make a reader delay the grace
	 * period, and we want a long delay occasionally to trigger
	 * force_quiescent_state. */
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	if (!(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms)))
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		mdelay(longdelay_ms);
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	if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
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		udelay(shortdelay_us);
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#ifdef CONFIG_PREEMPT
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	if (!preempt_count() &&
	    !(torture_random(rrsp) % (nrealreaders * 20000)))
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		preempt_schedule();  /* No QS if preempt_disable() in effect */
#endif
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}

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static void rcu_torture_read_unlock(int idx) __releases(RCU)
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{
	rcu_read_unlock();
}

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/*
 * Update callback in the pipe.  This should be invoked after a grace period.
 */
static bool
rcu_torture_pipe_update_one(struct rcu_torture *rp)
{
	int i;

	i = rp->rtort_pipe_count;
	if (i > RCU_TORTURE_PIPE_LEN)
		i = RCU_TORTURE_PIPE_LEN;
	atomic_inc(&rcu_torture_wcount[i]);
	if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
		rp->rtort_mbtest = 0;
		return true;
	}
	return false;
}

/*
 * Update all callbacks in the pipe.  Suitable for synchronous grace-period
 * primitives.
 */
static void
rcu_torture_pipe_update(struct rcu_torture *old_rp)
{
	struct rcu_torture *rp;
	struct rcu_torture *rp1;

	if (old_rp)
		list_add(&old_rp->rtort_free, &rcu_torture_removed);
	list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
		if (rcu_torture_pipe_update_one(rp)) {
			list_del(&rp->rtort_free);
			rcu_torture_free(rp);
		}
	}
}

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static void
rcu_torture_cb(struct rcu_head *p)
{
	struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);

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	if (torture_must_stop_irq()) {
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		/* Test is ending, just drop callbacks on the floor. */
		/* The next initialization will pick up the pieces. */
		return;
	}
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	if (rcu_torture_pipe_update_one(rp))
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		rcu_torture_free(rp);
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	else
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		cur_ops->deferred_free(rp);
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}

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static unsigned long rcu_no_completed(void)
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{
	return 0;
}

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static void rcu_torture_deferred_free(struct rcu_torture *p)
{
	call_rcu(&p->rtort_rcu, rcu_torture_cb);
}

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static void rcu_sync_torture_init(void)
{
	INIT_LIST_HEAD(&rcu_torture_removed);
}

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static struct rcu_torture_ops rcu_ops = {
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	.ttype		= RCU_FLAVOR,
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	.init		= rcu_sync_torture_init,
	.readlock	= rcu_torture_read_lock,
	.read_delay	= rcu_read_delay,
	.readunlock	= rcu_torture_read_unlock,
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	.started	= rcu_batches_started,
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	.completed	= rcu_batches_completed,
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	.deferred_free	= rcu_torture_deferred_free,
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	.sync		= synchronize_rcu,
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	.exp_sync	= synchronize_rcu_expedited,
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	.get_state	= get_state_synchronize_rcu,
	.cond_sync	= cond_synchronize_rcu,
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	.call		= call_rcu,
	.cb_barrier	= rcu_barrier,
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	.fqs		= rcu_force_quiescent_state,
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	.stats		= NULL,
	.irq_capable	= 1,
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	.can_boost	= rcu_can_boost(),
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	.name		= "rcu"
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};

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/*
 * Definitions for rcu_bh torture testing.
 */

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static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
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{
	rcu_read_lock_bh();
	return 0;
}

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static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
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{
	rcu_read_unlock_bh();
}

static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
{
	call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
}

static struct rcu_torture_ops rcu_bh_ops = {
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	.ttype		= RCU_BH_FLAVOR,
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	.init		= rcu_sync_torture_init,
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	.readlock	= rcu_bh_torture_read_lock,
	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */
	.readunlock	= rcu_bh_torture_read_unlock,
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	.started	= rcu_batches_started_bh,
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	.completed	= rcu_batches_completed_bh,
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	.deferred_free	= rcu_bh_torture_deferred_free,
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	.sync		= synchronize_rcu_bh,
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	.exp_sync	= synchronize_rcu_bh_expedited,
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	.call		= call_rcu_bh,
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	.cb_barrier	= rcu_barrier_bh,
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	.fqs		= rcu_bh_force_quiescent_state,
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	.stats		= NULL,
	.irq_capable	= 1,
	.name		= "rcu_bh"
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};

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/*
 * Don't even think about trying any of these in real life!!!
 * The names includes "busted", and they really means it!
 * The only purpose of these functions is to provide a buggy RCU
 * implementation to make sure that rcutorture correctly emits
 * buggy-RCU error messages.
 */
static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
{
	/* This is a deliberate bug for testing purposes only! */
	rcu_torture_cb(&p->rtort_rcu);
}

static void synchronize_rcu_busted(void)
{
	/* This is a deliberate bug for testing purposes only! */
}

static void
call_rcu_busted(struct rcu_head *head, void (*func)(struct rcu_head *rcu))
{
	/* This is a deliberate bug for testing purposes only! */
	func(head);
}

static struct rcu_torture_ops rcu_busted_ops = {
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	.ttype		= INVALID_RCU_FLAVOR,
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	.init		= rcu_sync_torture_init,
	.readlock	= rcu_torture_read_lock,
	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */
	.readunlock	= rcu_torture_read_unlock,
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	.started	= rcu_no_completed,
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	.completed	= rcu_no_completed,
	.deferred_free	= rcu_busted_torture_deferred_free,
	.sync		= synchronize_rcu_busted,
	.exp_sync	= synchronize_rcu_busted,
	.call		= call_rcu_busted,
	.cb_barrier	= NULL,
	.fqs		= NULL,
	.stats		= NULL,
	.irq_capable	= 1,
	.name		= "rcu_busted"
};

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/*
 * Definitions for srcu torture testing.
 */

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DEFINE_STATIC_SRCU(srcu_ctl);
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static struct srcu_struct srcu_ctld;
static struct srcu_struct *srcu_ctlp = &srcu_ctl;
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static int srcu_torture_read_lock(void) __acquires(srcu_ctlp)
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{
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	return srcu_read_lock(srcu_ctlp);
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}

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static void srcu_read_delay(struct torture_random_state *rrsp)
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{
	long delay;
	const long uspertick = 1000000 / HZ;
	const long longdelay = 10;

	/* We want there to be long-running readers, but not all the time. */

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	delay = torture_random(rrsp) %
		(nrealreaders * 2 * longdelay * uspertick);
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	if (!delay)
		schedule_timeout_interruptible(longdelay);
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	else
		rcu_read_delay(rrsp);
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}

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static void srcu_torture_read_unlock(int idx) __releases(srcu_ctlp)
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{
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	srcu_read_unlock(srcu_ctlp, idx);
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}

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static unsigned long srcu_torture_completed(void)
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{
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	return srcu_batches_completed(srcu_ctlp);
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}

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static void srcu_torture_deferred_free(struct rcu_torture *rp)
{
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	call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
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}

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static void srcu_torture_synchronize(void)
{
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	synchronize_srcu(srcu_ctlp);
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}

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static void srcu_torture_call(struct rcu_head *head,
			      void (*func)(struct rcu_head *head))
{
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	call_srcu(srcu_ctlp, head, func);
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}

static void srcu_torture_barrier(void)
{
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	srcu_barrier(srcu_ctlp);
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}

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static void srcu_torture_stats(void)
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{
	int cpu;
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	int idx = srcu_ctlp->completed & 0x1;
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	pr_alert("%s%s per-CPU(idx=%d):",
		 torture_type, TORTURE_FLAG, idx);
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	for_each_possible_cpu(cpu) {
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		long c0, c1;

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		c0 = (long)per_cpu_ptr(srcu_ctlp->per_cpu_ref, cpu)->c[!idx];
		c1 = (long)per_cpu_ptr(srcu_ctlp->per_cpu_ref, cpu)->c[idx];
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		pr_cont(" %d(%ld,%ld)", cpu, c0, c1);
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	}
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	pr_cont("\n");
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}

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static void srcu_torture_synchronize_expedited(void)
{
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	synchronize_srcu_expedited(srcu_ctlp);
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}

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static struct rcu_torture_ops srcu_ops = {
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	.ttype		= SRCU_FLAVOR,
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	.init		= rcu_sync_torture_init,
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	.readlock	= srcu_torture_read_lock,
	.read_delay	= srcu_read_delay,
	.readunlock	= srcu_torture_read_unlock,
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	.started	= NULL,
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	.completed	= srcu_torture_completed,
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	.deferred_free	= srcu_torture_deferred_free,
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	.sync		= srcu_torture_synchronize,
568
	.exp_sync	= srcu_torture_synchronize_expedited,
569 570
	.call		= srcu_torture_call,
	.cb_barrier	= srcu_torture_barrier,
571 572
	.stats		= srcu_torture_stats,
	.name		= "srcu"
573 574
};

575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606
static void srcu_torture_init(void)
{
	rcu_sync_torture_init();
	WARN_ON(init_srcu_struct(&srcu_ctld));
	srcu_ctlp = &srcu_ctld;
}

static void srcu_torture_cleanup(void)
{
	cleanup_srcu_struct(&srcu_ctld);
	srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
}

/* As above, but dynamically allocated. */
static struct rcu_torture_ops srcud_ops = {
	.ttype		= SRCU_FLAVOR,
	.init		= srcu_torture_init,
	.cleanup	= srcu_torture_cleanup,
	.readlock	= srcu_torture_read_lock,
	.read_delay	= srcu_read_delay,
	.readunlock	= srcu_torture_read_unlock,
	.started	= NULL,
	.completed	= srcu_torture_completed,
	.deferred_free	= srcu_torture_deferred_free,
	.sync		= srcu_torture_synchronize,
	.exp_sync	= srcu_torture_synchronize_expedited,
	.call		= srcu_torture_call,
	.cb_barrier	= srcu_torture_barrier,
	.stats		= srcu_torture_stats,
	.name		= "srcud"
};

607 608 609 610 611 612 613 614 615 616 617 618 619 620 621
/*
 * Definitions for sched torture testing.
 */

static int sched_torture_read_lock(void)
{
	preempt_disable();
	return 0;
}

static void sched_torture_read_unlock(int idx)
{
	preempt_enable();
}

622 623 624 625 626
static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
{
	call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
}

627
static struct rcu_torture_ops sched_ops = {
628
	.ttype		= RCU_SCHED_FLAVOR,
629 630 631 632
	.init		= rcu_sync_torture_init,
	.readlock	= sched_torture_read_lock,
	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */
	.readunlock	= sched_torture_read_unlock,
633
	.started	= rcu_batches_started_sched,
634
	.completed	= rcu_batches_completed_sched,
635
	.deferred_free	= rcu_sched_torture_deferred_free,
636
	.sync		= synchronize_sched,
637
	.exp_sync	= synchronize_sched_expedited,
638 639
	.get_state	= get_state_synchronize_sched,
	.cond_sync	= cond_synchronize_sched,
640
	.call		= call_rcu_sched,
641
	.cb_barrier	= rcu_barrier_sched,
642
	.fqs		= rcu_sched_force_quiescent_state,
643 644 645
	.stats		= NULL,
	.irq_capable	= 1,
	.name		= "sched"
646 647
};

648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673
#ifdef CONFIG_TASKS_RCU

/*
 * Definitions for RCU-tasks torture testing.
 */

static int tasks_torture_read_lock(void)
{
	return 0;
}

static void tasks_torture_read_unlock(int idx)
{
}

static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
{
	call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
}

static struct rcu_torture_ops tasks_ops = {
	.ttype		= RCU_TASKS_FLAVOR,
	.init		= rcu_sync_torture_init,
	.readlock	= tasks_torture_read_lock,
	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */
	.readunlock	= tasks_torture_read_unlock,
674
	.started	= rcu_no_completed,
675 676 677 678 679 680 681 682 683 684 685 686 687 688
	.completed	= rcu_no_completed,
	.deferred_free	= rcu_tasks_torture_deferred_free,
	.sync		= synchronize_rcu_tasks,
	.exp_sync	= synchronize_rcu_tasks,
	.call		= call_rcu_tasks,
	.cb_barrier	= rcu_barrier_tasks,
	.fqs		= NULL,
	.stats		= NULL,
	.irq_capable	= 1,
	.name		= "tasks"
};

#define RCUTORTURE_TASKS_OPS &tasks_ops,

689 690 691 692 693
static bool __maybe_unused torturing_tasks(void)
{
	return cur_ops == &tasks_ops;
}

694 695 696 697
#else /* #ifdef CONFIG_TASKS_RCU */

#define RCUTORTURE_TASKS_OPS

698 699 700 701 702
static bool torturing_tasks(void)
{
	return false;
}

703 704
#endif /* #else #ifdef CONFIG_TASKS_RCU */

705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721
/*
 * RCU torture priority-boost testing.  Runs one real-time thread per
 * CPU for moderate bursts, repeatedly registering RCU callbacks and
 * spinning waiting for them to be invoked.  If a given callback takes
 * too long to be invoked, we assume that priority inversion has occurred.
 */

struct rcu_boost_inflight {
	struct rcu_head rcu;
	int inflight;
};

static void rcu_torture_boost_cb(struct rcu_head *head)
{
	struct rcu_boost_inflight *rbip =
		container_of(head, struct rcu_boost_inflight, rcu);

722 723
	/* Ensure RCU-core accesses precede clearing ->inflight */
	smp_store_release(&rbip->inflight, 0);
724 725 726 727 728 729 730 731 732 733
}

static int rcu_torture_boost(void *arg)
{
	unsigned long call_rcu_time;
	unsigned long endtime;
	unsigned long oldstarttime;
	struct rcu_boost_inflight rbi = { .inflight = 0 };
	struct sched_param sp;

734
	VERBOSE_TOROUT_STRING("rcu_torture_boost started");
735 736 737 738

	/* Set real-time priority. */
	sp.sched_priority = 1;
	if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
739
		VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!");
740 741 742
		n_rcu_torture_boost_rterror++;
	}

743
	init_rcu_head_on_stack(&rbi.rcu);
744 745 746 747
	/* Each pass through the following loop does one boost-test cycle. */
	do {
		/* Wait for the next test interval. */
		oldstarttime = boost_starttime;
748
		while (ULONG_CMP_LT(jiffies, oldstarttime)) {
749
			schedule_timeout_interruptible(oldstarttime - jiffies);
750
			stutter_wait("rcu_torture_boost");
751
			if (torture_must_stop())
752 753 754 755 756 757
				goto checkwait;
		}

		/* Do one boost-test interval. */
		endtime = oldstarttime + test_boost_duration * HZ;
		call_rcu_time = jiffies;
758
		while (ULONG_CMP_LT(jiffies, endtime)) {
759
			/* If we don't have a callback in flight, post one. */
760 761 762
			if (!smp_load_acquire(&rbi.inflight)) {
				/* RCU core before ->inflight = 1. */
				smp_store_release(&rbi.inflight, 1);
763 764 765
				call_rcu(&rbi.rcu, rcu_torture_boost_cb);
				if (jiffies - call_rcu_time >
					 test_boost_duration * HZ - HZ / 2) {
766
					VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
767 768 769 770
					n_rcu_torture_boost_failure++;
				}
				call_rcu_time = jiffies;
			}
771
			cond_resched_rcu_qs();
772
			stutter_wait("rcu_torture_boost");
773
			if (torture_must_stop())
774 775 776 777 778 779 780 781 782 783
				goto checkwait;
		}

		/*
		 * Set the start time of the next test interval.
		 * Yes, this is vulnerable to long delays, but such
		 * delays simply cause a false negative for the next
		 * interval.  Besides, we are running at RT priority,
		 * so delays should be relatively rare.
		 */
784 785
		while (oldstarttime == boost_starttime &&
		       !kthread_should_stop()) {
786 787 788 789 790 791 792 793 794 795 796
			if (mutex_trylock(&boost_mutex)) {
				boost_starttime = jiffies +
						  test_boost_interval * HZ;
				n_rcu_torture_boosts++;
				mutex_unlock(&boost_mutex);
				break;
			}
			schedule_timeout_uninterruptible(1);
		}

		/* Go do the stutter. */
797
checkwait:	stutter_wait("rcu_torture_boost");
798
	} while (!torture_must_stop());
799 800

	/* Clean up and exit. */
801
	while (!kthread_should_stop() || smp_load_acquire(&rbi.inflight)) {
802
		torture_shutdown_absorb("rcu_torture_boost");
803
		schedule_timeout_uninterruptible(1);
804
	}
805
	destroy_rcu_head_on_stack(&rbi.rcu);
806
	torture_kthread_stopping("rcu_torture_boost");
807 808 809
	return 0;
}

810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837
static void rcu_torture_cbflood_cb(struct rcu_head *rhp)
{
}

/*
 * RCU torture callback-flood kthread.  Repeatedly induces bursts of calls
 * to call_rcu() or analogous, increasing the probability of occurrence
 * of callback-overflow corner cases.
 */
static int
rcu_torture_cbflood(void *arg)
{
	int err = 1;
	int i;
	int j;
	struct rcu_head *rhp;

	if (cbflood_n_per_burst > 0 &&
	    cbflood_inter_holdoff > 0 &&
	    cbflood_intra_holdoff > 0 &&
	    cur_ops->call &&
	    cur_ops->cb_barrier) {
		rhp = vmalloc(sizeof(*rhp) *
			      cbflood_n_burst * cbflood_n_per_burst);
		err = !rhp;
	}
	if (err) {
		VERBOSE_TOROUT_STRING("rcu_torture_cbflood disabled: Bad args or OOM");
838
		goto wait_for_stop;
839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855
	}
	VERBOSE_TOROUT_STRING("rcu_torture_cbflood task started");
	do {
		schedule_timeout_interruptible(cbflood_inter_holdoff);
		atomic_long_inc(&n_cbfloods);
		WARN_ON(signal_pending(current));
		for (i = 0; i < cbflood_n_burst; i++) {
			for (j = 0; j < cbflood_n_per_burst; j++) {
				cur_ops->call(&rhp[i * cbflood_n_per_burst + j],
					      rcu_torture_cbflood_cb);
			}
			schedule_timeout_interruptible(cbflood_intra_holdoff);
			WARN_ON(signal_pending(current));
		}
		cur_ops->cb_barrier();
		stutter_wait("rcu_torture_cbflood");
	} while (!torture_must_stop());
856
	vfree(rhp);
857
wait_for_stop:
858 859 860 861
	torture_kthread_stopping("rcu_torture_cbflood");
	return 0;
}

862 863 864 865 866 867 868 869 870 871 872
/*
 * RCU torture force-quiescent-state kthread.  Repeatedly induces
 * bursts of calls to force_quiescent_state(), increasing the probability
 * of occurrence of some important types of race conditions.
 */
static int
rcu_torture_fqs(void *arg)
{
	unsigned long fqs_resume_time;
	int fqs_burst_remaining;

873
	VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
874 875
	do {
		fqs_resume_time = jiffies + fqs_stutter * HZ;
876 877
		while (ULONG_CMP_LT(jiffies, fqs_resume_time) &&
		       !kthread_should_stop()) {
878 879 880
			schedule_timeout_interruptible(1);
		}
		fqs_burst_remaining = fqs_duration;
881 882
		while (fqs_burst_remaining > 0 &&
		       !kthread_should_stop()) {
883 884 885 886
			cur_ops->fqs();
			udelay(fqs_holdoff);
			fqs_burst_remaining -= fqs_holdoff;
		}
887
		stutter_wait("rcu_torture_fqs");
888
	} while (!torture_must_stop());
889
	torture_kthread_stopping("rcu_torture_fqs");
890 891 892
	return 0;
}

893 894 895 896 897 898 899 900
/*
 * RCU torture writer kthread.  Repeatedly substitutes a new structure
 * for that pointed to by rcu_torture_current, freeing the old structure
 * after a series of grace periods (the "pipeline").
 */
static int
rcu_torture_writer(void *arg)
{
901 902
	bool can_expedite = !rcu_gp_is_expedited();
	int expediting = 0;
903 904
	unsigned long gp_snap;
	bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal;
905
	bool gp_sync1 = gp_sync;
906 907 908
	int i;
	struct rcu_torture *rp;
	struct rcu_torture *old_rp;
909
	static DEFINE_TORTURE_RANDOM(rand);
910 911
	int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC,
			   RTWS_COND_GET, RTWS_SYNC };
912
	int nsynctypes = 0;
913

914
	VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
915 916 917 918 919 920
	pr_alert("%s" TORTURE_FLAG
		 " Grace periods expedited from boot/sysfs for %s,\n",
		 torture_type, cur_ops->name);
	pr_alert("%s" TORTURE_FLAG
		 " Testing of dynamic grace-period expediting diabled.\n",
		 torture_type);
921

922
	/* Initialize synctype[] array.  If none set, take default. */
923
	if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync1)
924
		gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true;
925 926 927 928 929 930 931 932 933 934 935 936
	if (gp_cond1 && cur_ops->get_state && cur_ops->cond_sync)
		synctype[nsynctypes++] = RTWS_COND_GET;
	else if (gp_cond && (!cur_ops->get_state || !cur_ops->cond_sync))
		pr_alert("rcu_torture_writer: gp_cond without primitives.\n");
	if (gp_exp1 && cur_ops->exp_sync)
		synctype[nsynctypes++] = RTWS_EXP_SYNC;
	else if (gp_exp && !cur_ops->exp_sync)
		pr_alert("rcu_torture_writer: gp_exp without primitives.\n");
	if (gp_normal1 && cur_ops->deferred_free)
		synctype[nsynctypes++] = RTWS_DEF_FREE;
	else if (gp_normal && !cur_ops->deferred_free)
		pr_alert("rcu_torture_writer: gp_normal without primitives.\n");
937 938 939 940
	if (gp_sync1 && cur_ops->sync)
		synctype[nsynctypes++] = RTWS_SYNC;
	else if (gp_sync && !cur_ops->sync)
		pr_alert("rcu_torture_writer: gp_sync without primitives.\n");
941 942
	if (WARN_ONCE(nsynctypes == 0,
		      "rcu_torture_writer: No update-side primitives.\n")) {
943 944 945 946 947
		/*
		 * No updates primitives, so don't try updating.
		 * The resulting test won't be testing much, hence the
		 * above WARN_ONCE().
		 */
948 949 950 951
		rcu_torture_writer_state = RTWS_STOPPING;
		torture_kthread_stopping("rcu_torture_writer");
	}

952
	do {
953
		rcu_torture_writer_state = RTWS_FIXED_DELAY;
954
		schedule_timeout_uninterruptible(1);
955 956
		rp = rcu_torture_alloc();
		if (rp == NULL)
957 958
			continue;
		rp->rtort_pipe_count = 0;
959
		rcu_torture_writer_state = RTWS_DELAY;
960
		udelay(torture_random(&rand) & 0x3ff);
961
		rcu_torture_writer_state = RTWS_REPLACE;
962 963
		old_rp = rcu_dereference_check(rcu_torture_current,
					       current == writer_task);
964
		rp->rtort_mbtest = 1;
965
		rcu_assign_pointer(rcu_torture_current, rp);
966
		smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
967
		if (old_rp) {
968 969 970 971 972
			i = old_rp->rtort_pipe_count;
			if (i > RCU_TORTURE_PIPE_LEN)
				i = RCU_TORTURE_PIPE_LEN;
			atomic_inc(&rcu_torture_wcount[i]);
			old_rp->rtort_pipe_count++;
973 974
			switch (synctype[torture_random(&rand) % nsynctypes]) {
			case RTWS_DEF_FREE:
975
				rcu_torture_writer_state = RTWS_DEF_FREE;
976
				cur_ops->deferred_free(old_rp);
977 978
				break;
			case RTWS_EXP_SYNC:
979
				rcu_torture_writer_state = RTWS_EXP_SYNC;
980
				cur_ops->exp_sync();
981 982 983 984 985 986 987 988 989 990 991 992 993
				rcu_torture_pipe_update(old_rp);
				break;
			case RTWS_COND_GET:
				rcu_torture_writer_state = RTWS_COND_GET;
				gp_snap = cur_ops->get_state();
				i = torture_random(&rand) % 16;
				if (i != 0)
					schedule_timeout_interruptible(i);
				udelay(torture_random(&rand) % 1000);
				rcu_torture_writer_state = RTWS_COND_SYNC;
				cur_ops->cond_sync(gp_snap);
				rcu_torture_pipe_update(old_rp);
				break;
994 995 996 997 998
			case RTWS_SYNC:
				rcu_torture_writer_state = RTWS_SYNC;
				cur_ops->sync();
				rcu_torture_pipe_update(old_rp);
				break;
999 1000 1001
			default:
				WARN_ON_ONCE(1);
				break;
1002
			}
1003
		}
1004
		rcutorture_record_progress(++rcu_torture_current_version);
1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015
		/* Cycle through nesting levels of rcu_expedite_gp() calls. */
		if (can_expedite &&
		    !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
			WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
			if (expediting >= 0)
				rcu_expedite_gp();
			else
				rcu_unexpedite_gp();
			if (++expediting > 3)
				expediting = -expediting;
		}
1016
		rcu_torture_writer_state = RTWS_STUTTER;
1017
		stutter_wait("rcu_torture_writer");
1018
	} while (!torture_must_stop());
1019 1020 1021 1022 1023 1024
	/* Reset expediting back to unexpedited. */
	if (expediting > 0)
		expediting = -expediting;
	while (can_expedite && expediting++ < 0)
		rcu_unexpedite_gp();
	WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
1025
	rcu_torture_writer_state = RTWS_STOPPING;
1026
	torture_kthread_stopping("rcu_torture_writer");
1027 1028 1029
	return 0;
}

1030 1031 1032 1033 1034 1035 1036
/*
 * RCU torture fake writer kthread.  Repeatedly calls sync, with a random
 * delay between calls.
 */
static int
rcu_torture_fakewriter(void *arg)
{
1037
	DEFINE_TORTURE_RANDOM(rand);
1038

1039
	VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1040
	set_user_nice(current, MAX_NICE);
1041 1042

	do {
1043 1044
		schedule_timeout_uninterruptible(1 + torture_random(&rand)%10);
		udelay(torture_random(&rand) & 0x3ff);
1045
		if (cur_ops->cb_barrier != NULL &&
1046
		    torture_random(&rand) % (nfakewriters * 8) == 0) {
1047
			cur_ops->cb_barrier();
1048
		} else if (gp_normal == gp_exp) {
1049
			if (torture_random(&rand) & 0x80)
1050 1051 1052 1053
				cur_ops->sync();
			else
				cur_ops->exp_sync();
		} else if (gp_normal) {
1054
			cur_ops->sync();
1055 1056 1057
		} else {
			cur_ops->exp_sync();
		}
1058
		stutter_wait("rcu_torture_fakewriter");
1059
	} while (!torture_must_stop());
1060

1061
	torture_kthread_stopping("rcu_torture_fakewriter");
1062 1063 1064
	return 0;
}

1065
static void rcutorture_trace_dump(void)
1066 1067 1068 1069 1070 1071 1072 1073 1074 1075
{
	static atomic_t beenhere = ATOMIC_INIT(0);

	if (atomic_read(&beenhere))
		return;
	if (atomic_xchg(&beenhere, 1) != 0)
		return;
	ftrace_dump(DUMP_ALL);
}

1076 1077 1078 1079 1080 1081 1082 1083 1084
/*
 * RCU torture reader from timer handler.  Dereferences rcu_torture_current,
 * incrementing the corresponding element of the pipeline array.  The
 * counter in the element should never be greater than 1, otherwise, the
 * RCU implementation is broken.
 */
static void rcu_torture_timer(unsigned long unused)
{
	int idx;
1085
	unsigned long started;
1086
	unsigned long completed;
1087
	static DEFINE_TORTURE_RANDOM(rand);
1088 1089 1090
	static DEFINE_SPINLOCK(rand_lock);
	struct rcu_torture *p;
	int pipe_count;
1091
	unsigned long long ts;
1092 1093

	idx = cur_ops->readlock();
1094 1095 1096 1097
	if (cur_ops->started)
		started = cur_ops->started();
	else
		started = cur_ops->completed();
1098
	ts = rcu_trace_clock_local();
1099 1100 1101
	p = rcu_dereference_check(rcu_torture_current,
				  rcu_read_lock_bh_held() ||
				  rcu_read_lock_sched_held() ||
1102 1103
				  srcu_read_lock_held(srcu_ctlp) ||
				  torturing_tasks());
1104 1105 1106 1107 1108 1109 1110 1111
	if (p == NULL) {
		/* Leave because rcu_torture_writer is not yet underway */
		cur_ops->readunlock(idx);
		return;
	}
	if (p->rtort_mbtest == 0)
		atomic_inc(&n_rcu_torture_mberror);
	spin_lock(&rand_lock);
1112
	cur_ops->read_delay(&rand);
1113 1114 1115 1116 1117 1118 1119 1120
	n_rcu_torture_timers++;
	spin_unlock(&rand_lock);
	preempt_disable();
	pipe_count = p->rtort_pipe_count;
	if (pipe_count > RCU_TORTURE_PIPE_LEN) {
		/* Should not happen, but... */
		pipe_count = RCU_TORTURE_PIPE_LEN;
	}
1121
	completed = cur_ops->completed();
1122 1123
	if (pipe_count > 1) {
		do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, ts,
1124
					  started, completed);
1125
		rcutorture_trace_dump();
1126
	}
R
Rusty Russell 已提交
1127
	__this_cpu_inc(rcu_torture_count[pipe_count]);
1128 1129 1130
	completed = completed - started;
	if (cur_ops->started)
		completed++;
1131 1132 1133 1134
	if (completed > RCU_TORTURE_PIPE_LEN) {
		/* Should not happen, but... */
		completed = RCU_TORTURE_PIPE_LEN;
	}
R
Rusty Russell 已提交
1135
	__this_cpu_inc(rcu_torture_batch[completed]);
1136 1137 1138 1139
	preempt_enable();
	cur_ops->readunlock(idx);
}

1140 1141 1142 1143 1144 1145 1146 1147 1148
/*
 * RCU torture reader kthread.  Repeatedly dereferences rcu_torture_current,
 * incrementing the corresponding element of the pipeline array.  The
 * counter in the element should never be greater than 1, otherwise, the
 * RCU implementation is broken.
 */
static int
rcu_torture_reader(void *arg)
{
1149
	unsigned long started;
1150
	unsigned long completed;
1151
	int idx;
1152
	DEFINE_TORTURE_RANDOM(rand);
1153 1154
	struct rcu_torture *p;
	int pipe_count;
1155
	struct timer_list t;
1156
	unsigned long long ts;
1157

1158
	VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
1159
	set_user_nice(current, MAX_NICE);
1160
	if (irqreader && cur_ops->irq_capable)
1161
		setup_timer_on_stack(&t, rcu_torture_timer, 0);
1162

1163
	do {
1164
		if (irqreader && cur_ops->irq_capable) {
1165
			if (!timer_pending(&t))
1166
				mod_timer(&t, jiffies + 1);
1167
		}
1168
		idx = cur_ops->readlock();
1169 1170 1171 1172
		if (cur_ops->started)
			started = cur_ops->started();
		else
			started = cur_ops->completed();
1173
		ts = rcu_trace_clock_local();
1174 1175 1176
		p = rcu_dereference_check(rcu_torture_current,
					  rcu_read_lock_bh_held() ||
					  rcu_read_lock_sched_held() ||
1177 1178
					  srcu_read_lock_held(srcu_ctlp) ||
					  torturing_tasks());
1179 1180
		if (p == NULL) {
			/* Wait for rcu_torture_writer to get underway */
1181
			cur_ops->readunlock(idx);
1182 1183 1184
			schedule_timeout_interruptible(HZ);
			continue;
		}
1185 1186
		if (p->rtort_mbtest == 0)
			atomic_inc(&n_rcu_torture_mberror);
1187
		cur_ops->read_delay(&rand);
1188 1189 1190 1191 1192 1193
		preempt_disable();
		pipe_count = p->rtort_pipe_count;
		if (pipe_count > RCU_TORTURE_PIPE_LEN) {
			/* Should not happen, but... */
			pipe_count = RCU_TORTURE_PIPE_LEN;
		}
1194
		completed = cur_ops->completed();
1195 1196
		if (pipe_count > 1) {
			do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
1197
						  ts, started, completed);
1198
			rcutorture_trace_dump();
1199
		}
R
Rusty Russell 已提交
1200
		__this_cpu_inc(rcu_torture_count[pipe_count]);
1201 1202 1203
		completed = completed - started;
		if (cur_ops->started)
			completed++;
1204 1205 1206 1207
		if (completed > RCU_TORTURE_PIPE_LEN) {
			/* Should not happen, but... */
			completed = RCU_TORTURE_PIPE_LEN;
		}
R
Rusty Russell 已提交
1208
		__this_cpu_inc(rcu_torture_batch[completed]);
1209
		preempt_enable();
1210
		cur_ops->readunlock(idx);
1211
		cond_resched_rcu_qs();
1212
		stutter_wait("rcu_torture_reader");
1213
	} while (!torture_must_stop());
1214
	if (irqreader && cur_ops->irq_capable) {
1215
		del_timer_sync(&t);
1216 1217
		destroy_timer_on_stack(&t);
	}
1218
	torture_kthread_stopping("rcu_torture_reader");
1219 1220 1221 1222
	return 0;
}

/*
1223 1224 1225 1226 1227 1228
 * Print torture statistics.  Caller must ensure that there is only
 * one call to this function at a given time!!!  This is normally
 * accomplished by relying on the module system to only have one copy
 * of the module loaded, and then by giving the rcu_torture_stats
 * kthread full control (or the init/cleanup functions when rcu_torture_stats
 * thread is not running).
1229
 */
1230
static void
1231
rcu_torture_stats_print(void)
1232 1233 1234 1235 1236
{
	int cpu;
	int i;
	long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
	long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1237
	static unsigned long rtcv_snap = ULONG_MAX;
1238

1239
	for_each_possible_cpu(cpu) {
1240 1241 1242 1243 1244 1245 1246 1247 1248
		for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
			pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
			batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
		}
	}
	for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
		if (pipesummary[i] != 0)
			break;
	}
1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266

	pr_alert("%s%s ", torture_type, TORTURE_FLAG);
	pr_cont("rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
		rcu_torture_current,
		rcu_torture_current_version,
		list_empty(&rcu_torture_freelist),
		atomic_read(&n_rcu_torture_alloc),
		atomic_read(&n_rcu_torture_alloc_fail),
		atomic_read(&n_rcu_torture_free));
	pr_cont("rtmbe: %d rtbke: %ld rtbre: %ld ",
		atomic_read(&n_rcu_torture_mberror),
		n_rcu_torture_boost_ktrerror,
		n_rcu_torture_boost_rterror);
	pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
		n_rcu_torture_boost_failure,
		n_rcu_torture_boosts,
		n_rcu_torture_timers);
	torture_onoff_stats();
1267
	pr_cont("barrier: %ld/%ld:%ld ",
1268 1269 1270
		n_barrier_successes,
		n_barrier_attempts,
		n_rcu_torture_barrier_error);
1271
	pr_cont("cbflood: %ld\n", atomic_long_read(&n_cbfloods));
1272 1273

	pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1274
	if (atomic_read(&n_rcu_torture_mberror) != 0 ||
1275
	    n_rcu_torture_barrier_error != 0 ||
1276 1277
	    n_rcu_torture_boost_ktrerror != 0 ||
	    n_rcu_torture_boost_rterror != 0 ||
1278 1279
	    n_rcu_torture_boost_failure != 0 ||
	    i > 1) {
1280
		pr_cont("%s", "!!! ");
1281
		atomic_inc(&n_rcu_torture_error);
1282
		WARN_ON_ONCE(1);
1283
	}
1284
	pr_cont("Reader Pipe: ");
1285
	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1286 1287 1288 1289 1290
		pr_cont(" %ld", pipesummary[i]);
	pr_cont("\n");

	pr_alert("%s%s ", torture_type, TORTURE_FLAG);
	pr_cont("Reader Batch: ");
1291
	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1292 1293 1294 1295 1296
		pr_cont(" %ld", batchsummary[i]);
	pr_cont("\n");

	pr_alert("%s%s ", torture_type, TORTURE_FLAG);
	pr_cont("Free-Block Circulation: ");
1297
	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1298
		pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
1299
	}
1300 1301
	pr_cont("\n");

1302
	if (cur_ops->stats)
1303
		cur_ops->stats();
1304 1305 1306 1307 1308 1309 1310 1311
	if (rtcv_snap == rcu_torture_current_version &&
	    rcu_torture_current != NULL) {
		int __maybe_unused flags;
		unsigned long __maybe_unused gpnum;
		unsigned long __maybe_unused completed;

		rcutorture_get_gp_data(cur_ops->ttype,
				       &flags, &gpnum, &completed);
1312 1313 1314
		pr_alert("??? Writer stall state %d g%lu c%lu f%#x\n",
			 rcu_torture_writer_state,
			 gpnum, completed, flags);
1315
		show_rcu_gp_kthreads();
1316
		rcutorture_trace_dump();
1317 1318
	}
	rtcv_snap = rcu_torture_current_version;
1319 1320 1321 1322 1323 1324 1325 1326 1327
}

/*
 * Periodically prints torture statistics, if periodic statistics printing
 * was specified via the stat_interval module parameter.
 */
static int
rcu_torture_stats(void *arg)
{
1328
	VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1329 1330 1331
	do {
		schedule_timeout_interruptible(stat_interval * HZ);
		rcu_torture_stats_print();
1332
		torture_shutdown_absorb("rcu_torture_stats");
1333
	} while (!torture_must_stop());
1334
	torture_kthread_stopping("rcu_torture_stats");
1335 1336 1337
	return 0;
}

1338
static inline void
1339
rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1340
{
1341 1342 1343 1344 1345 1346 1347
	pr_alert("%s" TORTURE_FLAG
		 "--- %s: nreaders=%d nfakewriters=%d "
		 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
		 "shuffle_interval=%d stutter=%d irqreader=%d "
		 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
		 "test_boost=%d/%d test_boost_interval=%d "
		 "test_boost_duration=%d shutdown_secs=%d "
1348 1349
		 "stall_cpu=%d stall_cpu_holdoff=%d "
		 "n_barrier_cbs=%d "
1350 1351 1352 1353 1354 1355
		 "onoff_interval=%d onoff_holdoff=%d\n",
		 torture_type, tag, nrealreaders, nfakewriters,
		 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
		 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
		 test_boost, cur_ops->can_boost,
		 test_boost_interval, test_boost_duration, shutdown_secs,
1356 1357
		 stall_cpu, stall_cpu_holdoff,
		 n_barrier_cbs,
1358
		 onoff_interval, onoff_holdoff);
1359 1360
}

1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372
static void rcutorture_booster_cleanup(int cpu)
{
	struct task_struct *t;

	if (boost_tasks[cpu] == NULL)
		return;
	mutex_lock(&boost_mutex);
	t = boost_tasks[cpu];
	boost_tasks[cpu] = NULL;
	mutex_unlock(&boost_mutex);

	/* This must be outside of the mutex, otherwise deadlock! */
1373
	torture_stop_kthread(rcu_torture_boost, t);
1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384
}

static int rcutorture_booster_init(int cpu)
{
	int retval;

	if (boost_tasks[cpu] != NULL)
		return 0;  /* Already created, nothing more to do. */

	/* Don't allow time recalculation while creating a new task. */
	mutex_lock(&boost_mutex);
1385
	VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
E
Eric Dumazet 已提交
1386 1387 1388
	boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
						  cpu_to_node(cpu),
						  "rcu_torture_boost");
1389 1390
	if (IS_ERR(boost_tasks[cpu])) {
		retval = PTR_ERR(boost_tasks[cpu]);
1391
		VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402
		n_rcu_torture_boost_ktrerror++;
		boost_tasks[cpu] = NULL;
		mutex_unlock(&boost_mutex);
		return retval;
	}
	kthread_bind(boost_tasks[cpu], cpu);
	wake_up_process(boost_tasks[cpu]);
	mutex_unlock(&boost_mutex);
	return 0;
}

1403 1404 1405 1406
/*
 * CPU-stall kthread.  It waits as specified by stall_cpu_holdoff, then
 * induces a CPU stall for the time specified by stall_cpu.
 */
1407
static int rcu_torture_stall(void *args)
1408 1409 1410
{
	unsigned long stop_at;

1411
	VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
1412
	if (stall_cpu_holdoff > 0) {
1413
		VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
1414
		schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
1415
		VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
1416 1417 1418 1419
	}
	if (!kthread_should_stop()) {
		stop_at = get_seconds() + stall_cpu;
		/* RCU CPU stall is expected behavior in following code. */
1420
		pr_alert("rcu_torture_stall start.\n");
1421 1422 1423 1424 1425 1426
		rcu_read_lock();
		preempt_disable();
		while (ULONG_CMP_LT(get_seconds(), stop_at))
			continue;  /* Induce RCU CPU stall warning. */
		preempt_enable();
		rcu_read_unlock();
1427
		pr_alert("rcu_torture_stall end.\n");
1428
	}
1429
	torture_shutdown_absorb("rcu_torture_stall");
1430 1431 1432 1433 1434 1435 1436 1437 1438 1439
	while (!kthread_should_stop())
		schedule_timeout_interruptible(10 * HZ);
	return 0;
}

/* Spawn CPU-stall kthread, if stall_cpu specified. */
static int __init rcu_torture_stall_init(void)
{
	if (stall_cpu <= 0)
		return 0;
1440
	return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
1441 1442
}

1443
/* Callback function for RCU barrier testing. */
1444
static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
1445 1446 1447 1448 1449 1450 1451 1452
{
	atomic_inc(&barrier_cbs_invoked);
}

/* kthread function to register callbacks used to test RCU barriers. */
static int rcu_torture_barrier_cbs(void *arg)
{
	long myid = (long)arg;
1453
	bool lastphase = 0;
1454
	bool newphase;
1455 1456 1457
	struct rcu_head rcu;

	init_rcu_head_on_stack(&rcu);
1458
	VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
1459
	set_user_nice(current, MAX_NICE);
1460 1461
	do {
		wait_event(barrier_cbs_wq[myid],
1462
			   (newphase =
1463
			    smp_load_acquire(&barrier_phase)) != lastphase ||
1464
			   torture_must_stop());
1465
		lastphase = newphase;
1466
		if (torture_must_stop())
1467
			break;
1468 1469 1470 1471
		/*
		 * The above smp_load_acquire() ensures barrier_phase load
		 * is ordered before the folloiwng ->call().
		 */
1472 1473 1474
		cur_ops->call(&rcu, rcu_torture_barrier_cbf);
		if (atomic_dec_and_test(&barrier_cbs_count))
			wake_up(&barrier_wq);
1475
	} while (!torture_must_stop());
1476 1477
	if (cur_ops->cb_barrier != NULL)
		cur_ops->cb_barrier();
1478
	destroy_rcu_head_on_stack(&rcu);
1479
	torture_kthread_stopping("rcu_torture_barrier_cbs");
1480 1481 1482 1483 1484 1485 1486 1487
	return 0;
}

/* kthread function to drive and coordinate RCU barrier testing. */
static int rcu_torture_barrier(void *arg)
{
	int i;

1488
	VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
1489 1490 1491
	do {
		atomic_set(&barrier_cbs_invoked, 0);
		atomic_set(&barrier_cbs_count, n_barrier_cbs);
1492 1493
		/* Ensure barrier_phase ordered after prior assignments. */
		smp_store_release(&barrier_phase, !barrier_phase);
1494 1495 1496 1497
		for (i = 0; i < n_barrier_cbs; i++)
			wake_up(&barrier_cbs_wq[i]);
		wait_event(barrier_wq,
			   atomic_read(&barrier_cbs_count) == 0 ||
1498 1499
			   torture_must_stop());
		if (torture_must_stop())
1500 1501
			break;
		n_barrier_attempts++;
1502
		cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
1503 1504
		if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
			n_rcu_torture_barrier_error++;
1505 1506 1507
			pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
			       atomic_read(&barrier_cbs_invoked),
			       n_barrier_cbs);
1508 1509 1510 1511
			WARN_ON_ONCE(1);
		}
		n_barrier_successes++;
		schedule_timeout_interruptible(HZ / 10);
1512
	} while (!torture_must_stop());
1513
	torture_kthread_stopping("rcu_torture_barrier");
1514 1515 1516 1517 1518 1519 1520 1521 1522
	return 0;
}

/* Initialize RCU barrier testing. */
static int rcu_torture_barrier_init(void)
{
	int i;
	int ret;

1523
	if (n_barrier_cbs <= 0)
1524 1525
		return 0;
	if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
1526 1527 1528 1529 1530 1531
		pr_alert("%s" TORTURE_FLAG
			 " Call or barrier ops missing for %s,\n",
			 torture_type, cur_ops->name);
		pr_alert("%s" TORTURE_FLAG
			 " RCU barrier testing omitted from run.\n",
			 torture_type);
1532 1533 1534 1535 1536 1537 1538 1539 1540 1541
		return 0;
	}
	atomic_set(&barrier_cbs_count, 0);
	atomic_set(&barrier_cbs_invoked, 0);
	barrier_cbs_tasks =
		kzalloc(n_barrier_cbs * sizeof(barrier_cbs_tasks[0]),
			GFP_KERNEL);
	barrier_cbs_wq =
		kzalloc(n_barrier_cbs * sizeof(barrier_cbs_wq[0]),
			GFP_KERNEL);
1542
	if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
1543 1544 1545
		return -ENOMEM;
	for (i = 0; i < n_barrier_cbs; i++) {
		init_waitqueue_head(&barrier_cbs_wq[i]);
1546 1547 1548 1549
		ret = torture_create_kthread(rcu_torture_barrier_cbs,
					     (void *)(long)i,
					     barrier_cbs_tasks[i]);
		if (ret)
1550 1551
			return ret;
	}
1552
	return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
1553 1554 1555 1556 1557 1558 1559
}

/* Clean up after RCU barrier testing. */
static void rcu_torture_barrier_cleanup(void)
{
	int i;

1560
	torture_stop_kthread(rcu_torture_barrier, barrier_task);
1561
	if (barrier_cbs_tasks != NULL) {
1562 1563 1564
		for (i = 0; i < n_barrier_cbs; i++)
			torture_stop_kthread(rcu_torture_barrier_cbs,
					     barrier_cbs_tasks[i]);
1565 1566 1567 1568 1569 1570 1571 1572 1573
		kfree(barrier_cbs_tasks);
		barrier_cbs_tasks = NULL;
	}
	if (barrier_cbs_wq != NULL) {
		kfree(barrier_cbs_wq);
		barrier_cbs_wq = NULL;
	}
}

1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596
static int rcutorture_cpu_notify(struct notifier_block *self,
				 unsigned long action, void *hcpu)
{
	long cpu = (long)hcpu;

	switch (action) {
	case CPU_ONLINE:
	case CPU_DOWN_FAILED:
		(void)rcutorture_booster_init(cpu);
		break;
	case CPU_DOWN_PREPARE:
		rcutorture_booster_cleanup(cpu);
		break;
	default:
		break;
	}
	return NOTIFY_OK;
}

static struct notifier_block rcutorture_cpu_nb = {
	.notifier_call = rcutorture_cpu_notify,
};

1597 1598 1599 1600 1601
static void
rcu_torture_cleanup(void)
{
	int i;

1602
	rcutorture_record_test_transition();
1603
	if (torture_cleanup_begin()) {
1604 1605 1606 1607
		if (cur_ops->cb_barrier != NULL)
			cur_ops->cb_barrier();
		return;
	}
1608

1609
	rcu_torture_barrier_cleanup();
1610 1611
	torture_stop_kthread(rcu_torture_stall, stall_task);
	torture_stop_kthread(rcu_torture_writer, writer_task);
1612

1613
	if (reader_tasks) {
1614 1615 1616
		for (i = 0; i < nrealreaders; i++)
			torture_stop_kthread(rcu_torture_reader,
					     reader_tasks[i]);
1617 1618 1619 1620
		kfree(reader_tasks);
	}
	rcu_torture_current = NULL;

1621
	if (fakewriter_tasks) {
1622
		for (i = 0; i < nfakewriters; i++) {
1623 1624
			torture_stop_kthread(rcu_torture_fakewriter,
					     fakewriter_tasks[i]);
1625 1626 1627 1628 1629
		}
		kfree(fakewriter_tasks);
		fakewriter_tasks = NULL;
	}

1630 1631
	torture_stop_kthread(rcu_torture_stats, stats_task);
	torture_stop_kthread(rcu_torture_fqs, fqs_task);
1632 1633
	for (i = 0; i < ncbflooders; i++)
		torture_stop_kthread(rcu_torture_cbflood, cbflood_task[i]);
1634 1635 1636 1637 1638 1639
	if ((test_boost == 1 && cur_ops->can_boost) ||
	    test_boost == 2) {
		unregister_cpu_notifier(&rcutorture_cpu_nb);
		for_each_possible_cpu(i)
			rcutorture_booster_cleanup(i);
	}
1640

1641 1642 1643 1644
	/*
	 * Wait for all RCU callbacks to fire, then do flavor-specific
	 * cleanup operations.
	 */
1645 1646
	if (cur_ops->cb_barrier != NULL)
		cur_ops->cb_barrier();
1647 1648
	if (cur_ops->cleanup != NULL)
		cur_ops->cleanup();
1649 1650

	rcu_torture_stats_print();  /* -After- the stats thread is stopped! */
1651

1652
	if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
1653
		rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
1654
	else if (torture_onoff_failures())
1655 1656
		rcu_torture_print_module_parms(cur_ops,
					       "End of test: RCU_HOTPLUG");
1657
	else
1658
		rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
1659
	torture_cleanup_end();
1660 1661
}

1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717
#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
static void rcu_torture_leak_cb(struct rcu_head *rhp)
{
}

static void rcu_torture_err_cb(struct rcu_head *rhp)
{
	/*
	 * This -might- happen due to race conditions, but is unlikely.
	 * The scenario that leads to this happening is that the
	 * first of the pair of duplicate callbacks is queued,
	 * someone else starts a grace period that includes that
	 * callback, then the second of the pair must wait for the
	 * next grace period.  Unlikely, but can happen.  If it
	 * does happen, the debug-objects subsystem won't have splatted.
	 */
	pr_alert("rcutorture: duplicated callback was invoked.\n");
}
#endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */

/*
 * Verify that double-free causes debug-objects to complain, but only
 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y.  Otherwise, say that the test
 * cannot be carried out.
 */
static void rcu_test_debug_objects(void)
{
#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
	struct rcu_head rh1;
	struct rcu_head rh2;

	init_rcu_head_on_stack(&rh1);
	init_rcu_head_on_stack(&rh2);
	pr_alert("rcutorture: WARN: Duplicate call_rcu() test starting.\n");

	/* Try to queue the rh2 pair of callbacks for the same grace period. */
	preempt_disable(); /* Prevent preemption from interrupting test. */
	rcu_read_lock(); /* Make it impossible to finish a grace period. */
	call_rcu(&rh1, rcu_torture_leak_cb); /* Start grace period. */
	local_irq_disable(); /* Make it harder to start a new grace period. */
	call_rcu(&rh2, rcu_torture_leak_cb);
	call_rcu(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
	local_irq_enable();
	rcu_read_unlock();
	preempt_enable();

	/* Wait for them all to get done so we can safely return. */
	rcu_barrier();
	pr_alert("rcutorture: WARN: Duplicate call_rcu() test complete.\n");
	destroy_rcu_head_on_stack(&rh1);
	destroy_rcu_head_on_stack(&rh2);
#else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
	pr_alert("rcutorture: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n");
#endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
}

1718
static int __init
1719 1720 1721 1722 1723
rcu_torture_init(void)
{
	int i;
	int cpu;
	int firsterr = 0;
1724
	static struct rcu_torture_ops *torture_ops[] = {
1725 1726
		&rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops,
		&sched_ops, RCUTORTURE_TASKS_OPS
1727
	};
1728

1729
	if (!torture_init_begin(torture_type, verbose, &torture_runnable))
1730
		return -EBUSY;
1731

1732
	/* Process args and tell the world that the torturer is on the job. */
1733
	for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1734
		cur_ops = torture_ops[i];
1735
		if (strcmp(torture_type, cur_ops->name) == 0)
1736 1737
			break;
	}
1738
	if (i == ARRAY_SIZE(torture_ops)) {
1739 1740 1741
		pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
			 torture_type);
		pr_alert("rcu-torture types:");
1742
		for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1743 1744
			pr_alert(" %s", torture_ops[i]->name);
		pr_alert("\n");
1745
		torture_init_end();
1746
		return -EINVAL;
1747
	}
1748
	if (cur_ops->fqs == NULL && fqs_duration != 0) {
1749
		pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
1750 1751
		fqs_duration = 0;
	}
1752
	if (cur_ops->init)
1753 1754
		cur_ops->init(); /* no "goto unwind" prior to this point!!! */

1755
	if (nreaders >= 0) {
1756
		nrealreaders = nreaders;
1757
	} else {
1758
		nrealreaders = num_online_cpus() - 2 - nreaders;
1759 1760 1761
		if (nrealreaders <= 0)
			nrealreaders = 1;
	}
1762
	rcu_torture_print_module_parms(cur_ops, "Start of test");
1763 1764 1765 1766

	/* Set up the freelist. */

	INIT_LIST_HEAD(&rcu_torture_freelist);
1767
	for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1768
		rcu_tortures[i].rtort_mbtest = 0;
1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779
		list_add_tail(&rcu_tortures[i].rtort_free,
			      &rcu_torture_freelist);
	}

	/* Initialize the statistics so that each run gets its own numbers. */

	rcu_torture_current = NULL;
	rcu_torture_current_version = 0;
	atomic_set(&n_rcu_torture_alloc, 0);
	atomic_set(&n_rcu_torture_alloc_fail, 0);
	atomic_set(&n_rcu_torture_free, 0);
1780 1781
	atomic_set(&n_rcu_torture_mberror, 0);
	atomic_set(&n_rcu_torture_error, 0);
1782
	n_rcu_torture_barrier_error = 0;
1783 1784 1785 1786
	n_rcu_torture_boost_ktrerror = 0;
	n_rcu_torture_boost_rterror = 0;
	n_rcu_torture_boost_failure = 0;
	n_rcu_torture_boosts = 0;
1787 1788
	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
		atomic_set(&rcu_torture_wcount[i], 0);
1789
	for_each_possible_cpu(cpu) {
1790 1791 1792 1793 1794 1795 1796 1797
		for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
			per_cpu(rcu_torture_count, cpu)[i] = 0;
			per_cpu(rcu_torture_batch, cpu)[i] = 0;
		}
	}

	/* Start up the kthreads. */

1798 1799 1800
	firsterr = torture_create_kthread(rcu_torture_writer, NULL,
					  writer_task);
	if (firsterr)
1801
		goto unwind;
1802 1803 1804 1805 1806 1807 1808 1809 1810
	if (nfakewriters > 0) {
		fakewriter_tasks = kzalloc(nfakewriters *
					   sizeof(fakewriter_tasks[0]),
					   GFP_KERNEL);
		if (fakewriter_tasks == NULL) {
			VERBOSE_TOROUT_ERRSTRING("out of memory");
			firsterr = -ENOMEM;
			goto unwind;
		}
1811 1812
	}
	for (i = 0; i < nfakewriters; i++) {
1813 1814 1815
		firsterr = torture_create_kthread(rcu_torture_fakewriter,
						  NULL, fakewriter_tasks[i]);
		if (firsterr)
1816 1817
			goto unwind;
	}
1818
	reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
1819 1820
			       GFP_KERNEL);
	if (reader_tasks == NULL) {
1821
		VERBOSE_TOROUT_ERRSTRING("out of memory");
1822 1823 1824 1825
		firsterr = -ENOMEM;
		goto unwind;
	}
	for (i = 0; i < nrealreaders; i++) {
1826 1827 1828
		firsterr = torture_create_kthread(rcu_torture_reader, NULL,
						  reader_tasks[i]);
		if (firsterr)
1829 1830 1831
			goto unwind;
	}
	if (stat_interval > 0) {
1832 1833 1834
		firsterr = torture_create_kthread(rcu_torture_stats, NULL,
						  stats_task);
		if (firsterr)
1835 1836
			goto unwind;
	}
1837
	if (test_no_idle_hz && shuffle_interval > 0) {
1838 1839
		firsterr = torture_shuffle_init(shuffle_interval * HZ);
		if (firsterr)
1840 1841
			goto unwind;
	}
1842 1843 1844
	if (stutter < 0)
		stutter = 0;
	if (stutter) {
1845 1846
		firsterr = torture_stutter_init(stutter * HZ);
		if (firsterr)
1847 1848
			goto unwind;
	}
1849 1850 1851
	if (fqs_duration < 0)
		fqs_duration = 0;
	if (fqs_duration) {
1852
		/* Create the fqs thread */
1853 1854
		firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
						  fqs_task);
1855
		if (firsterr)
1856 1857
			goto unwind;
	}
1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869
	if (test_boost_interval < 1)
		test_boost_interval = 1;
	if (test_boost_duration < 2)
		test_boost_duration = 2;
	if ((test_boost == 1 && cur_ops->can_boost) ||
	    test_boost == 2) {

		boost_starttime = jiffies + test_boost_interval * HZ;
		register_cpu_notifier(&rcutorture_cpu_nb);
		for_each_possible_cpu(i) {
			if (cpu_is_offline(i))
				continue;  /* Heuristic: CPU can go offline. */
1870 1871
			firsterr = rcutorture_booster_init(i);
			if (firsterr)
1872 1873 1874
				goto unwind;
		}
	}
1875 1876
	firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
	if (firsterr)
1877
		goto unwind;
1878 1879
	firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval * HZ);
	if (firsterr)
1880
		goto unwind;
1881 1882
	firsterr = rcu_torture_stall_init();
	if (firsterr)
1883
		goto unwind;
1884 1885
	firsterr = rcu_torture_barrier_init();
	if (firsterr)
1886
		goto unwind;
1887 1888
	if (object_debug)
		rcu_test_debug_objects();
1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906
	if (cbflood_n_burst > 0) {
		/* Create the cbflood threads */
		ncbflooders = (num_online_cpus() + 3) / 4;
		cbflood_task = kcalloc(ncbflooders, sizeof(*cbflood_task),
				       GFP_KERNEL);
		if (!cbflood_task) {
			VERBOSE_TOROUT_ERRSTRING("out of memory");
			firsterr = -ENOMEM;
			goto unwind;
		}
		for (i = 0; i < ncbflooders; i++) {
			firsterr = torture_create_kthread(rcu_torture_cbflood,
							  NULL,
							  cbflood_task[i]);
			if (firsterr)
				goto unwind;
		}
	}
1907
	rcutorture_record_test_transition();
1908
	torture_init_end();
1909 1910 1911
	return 0;

unwind:
1912
	torture_init_end();
1913 1914 1915 1916 1917 1918
	rcu_torture_cleanup();
	return firsterr;
}

module_init(rcu_torture_init);
module_exit(rcu_torture_cleanup);