rcutorture.c 54.7 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 已提交
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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>
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#include <linux/sched/signal.h>
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#include <uapi/linux/sched/types.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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#include "rcu.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);
static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch);
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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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static const char * const rcu_torture_writer_state_names[] = {
	"RTWS_FIXED_DELAY",
	"RTWS_DELAY",
	"RTWS_REPLACE",
	"RTWS_DEF_FREE",
	"RTWS_EXP_SYNC",
	"RTWS_COND_GET",
	"RTWS_COND_SYNC",
	"RTWS_SYNC",
	"RTWS_STUTTER",
	"RTWS_STOPPING",
};

static const char *rcu_torture_writer_state_getname(void)
{
	unsigned int i = READ_ONCE(rcu_torture_writer_state);

	if (i >= ARRAY_SIZE(rcu_torture_writer_state_names))
		return "???";
	return rcu_torture_writer_state_names[i];
}
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static int torture_runnable = IS_ENABLED(MODULE);
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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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	call_rcu_func_t call;
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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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	unsigned long started;
	unsigned long completed;
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	const unsigned long shortdelay_us = 200;
	const unsigned long longdelay_ms = 50;
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	unsigned long long ts;
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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))) {
		started = cur_ops->completed();
		ts = rcu_trace_clock_local();
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		mdelay(longdelay_ms);
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		completed = cur_ops->completed();
		do_trace_rcu_torture_read(cur_ops->name, NULL, ts,
					  started, completed);
	}
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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
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call_rcu_busted(struct rcu_head *head, rcu_callback_t func)
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{
	/* 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,
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			      rcu_callback_t func)
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{
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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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{
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	int __maybe_unused cpu;
	int idx;
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#ifdef CONFIG_TREE_SRCU
	idx = srcu_ctlp->srcu_idx & 0x1;
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	pr_alert("%s%s Tree SRCU per-CPU(idx=%d):",
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		 torture_type, TORTURE_FLAG, idx);
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	for_each_possible_cpu(cpu) {
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		unsigned long l0, l1;
		unsigned long u0, u1;
574
		long c0, c1;
575
		struct srcu_data *counts;
576

577 578 579
		counts = per_cpu_ptr(srcu_ctlp->sda, cpu);
		u0 = counts->srcu_unlock_count[!idx];
		u1 = counts->srcu_unlock_count[idx];
580 581 582 583 584 585 586

		/*
		 * Make sure that a lock is always counted if the corresponding
		 * unlock is counted.
		 */
		smp_rmb();

587 588
		l0 = counts->srcu_lock_count[!idx];
		l1 = counts->srcu_lock_count[idx];
589 590 591

		c0 = l0 - u0;
		c1 = l1 - u1;
592
		pr_cont(" %d(%ld,%ld)", cpu, c0, c1);
593
	}
594
	pr_cont("\n");
595 596
#elif defined(CONFIG_TINY_SRCU)
	idx = READ_ONCE(srcu_ctlp->srcu_idx) & 0x1;
597
	pr_alert("%s%s Tiny SRCU per-CPU(idx=%d): (%hd,%hd)\n",
598 599 600
		 torture_type, TORTURE_FLAG, idx,
		 READ_ONCE(srcu_ctlp->srcu_lock_nesting[!idx]),
		 READ_ONCE(srcu_ctlp->srcu_lock_nesting[idx]));
P
Paul E. McKenney 已提交
601
#endif
602 603
}

604 605
static void srcu_torture_synchronize_expedited(void)
{
606
	synchronize_srcu_expedited(srcu_ctlp);
607 608
}

609
static struct rcu_torture_ops srcu_ops = {
610
	.ttype		= SRCU_FLAVOR,
611
	.init		= rcu_sync_torture_init,
612 613 614
	.readlock	= srcu_torture_read_lock,
	.read_delay	= srcu_read_delay,
	.readunlock	= srcu_torture_read_unlock,
615
	.started	= NULL,
616
	.completed	= srcu_torture_completed,
617
	.deferred_free	= srcu_torture_deferred_free,
618
	.sync		= srcu_torture_synchronize,
619
	.exp_sync	= srcu_torture_synchronize_expedited,
620 621
	.call		= srcu_torture_call,
	.cb_barrier	= srcu_torture_barrier,
622 623
	.stats		= srcu_torture_stats,
	.name		= "srcu"
624 625
};

626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657
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"
};

658 659 660 661 662 663 664 665 666 667 668 669 670 671 672
/*
 * 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();
}

673 674 675 676 677
static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
{
	call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
}

678
static struct rcu_torture_ops sched_ops = {
679
	.ttype		= RCU_SCHED_FLAVOR,
680 681 682 683
	.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,
684
	.started	= rcu_batches_started_sched,
685
	.completed	= rcu_batches_completed_sched,
686
	.deferred_free	= rcu_sched_torture_deferred_free,
687
	.sync		= synchronize_sched,
688
	.exp_sync	= synchronize_sched_expedited,
689 690
	.get_state	= get_state_synchronize_sched,
	.cond_sync	= cond_synchronize_sched,
691
	.call		= call_rcu_sched,
692
	.cb_barrier	= rcu_barrier_sched,
693
	.fqs		= rcu_sched_force_quiescent_state,
694 695 696
	.stats		= NULL,
	.irq_capable	= 1,
	.name		= "sched"
697 698
};

699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724
#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,
725
	.started	= rcu_no_completed,
726 727 728 729 730 731 732 733 734 735 736 737 738 739
	.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,

740 741 742 743 744
static bool __maybe_unused torturing_tasks(void)
{
	return cur_ops == &tasks_ops;
}

745 746 747 748
#else /* #ifdef CONFIG_TASKS_RCU */

#define RCUTORTURE_TASKS_OPS

749
static bool __maybe_unused torturing_tasks(void)
750 751 752 753
{
	return false;
}

754 755
#endif /* #else #ifdef CONFIG_TASKS_RCU */

756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772
/*
 * 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);

773 774
	/* Ensure RCU-core accesses precede clearing ->inflight */
	smp_store_release(&rbip->inflight, 0);
775 776 777 778 779 780 781 782 783 784
}

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;

785
	VERBOSE_TOROUT_STRING("rcu_torture_boost started");
786 787 788 789

	/* Set real-time priority. */
	sp.sched_priority = 1;
	if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
790
		VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!");
791 792 793
		n_rcu_torture_boost_rterror++;
	}

794
	init_rcu_head_on_stack(&rbi.rcu);
795 796 797 798
	/* Each pass through the following loop does one boost-test cycle. */
	do {
		/* Wait for the next test interval. */
		oldstarttime = boost_starttime;
799
		while (ULONG_CMP_LT(jiffies, oldstarttime)) {
800
			schedule_timeout_interruptible(oldstarttime - jiffies);
801
			stutter_wait("rcu_torture_boost");
802
			if (torture_must_stop())
803 804 805 806 807 808
				goto checkwait;
		}

		/* Do one boost-test interval. */
		endtime = oldstarttime + test_boost_duration * HZ;
		call_rcu_time = jiffies;
809
		while (ULONG_CMP_LT(jiffies, endtime)) {
810
			/* If we don't have a callback in flight, post one. */
811 812 813
			if (!smp_load_acquire(&rbi.inflight)) {
				/* RCU core before ->inflight = 1. */
				smp_store_release(&rbi.inflight, 1);
814 815 816
				call_rcu(&rbi.rcu, rcu_torture_boost_cb);
				if (jiffies - call_rcu_time >
					 test_boost_duration * HZ - HZ / 2) {
817
					VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
818 819 820 821
					n_rcu_torture_boost_failure++;
				}
				call_rcu_time = jiffies;
			}
822
			stutter_wait("rcu_torture_boost");
823
			if (torture_must_stop())
824 825 826 827 828 829 830 831 832 833
				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.
		 */
834 835
		while (oldstarttime == boost_starttime &&
		       !kthread_should_stop()) {
836 837 838 839 840 841 842 843 844 845 846
			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. */
847
checkwait:	stutter_wait("rcu_torture_boost");
848
	} while (!torture_must_stop());
849 850

	/* Clean up and exit. */
851
	while (!kthread_should_stop() || smp_load_acquire(&rbi.inflight)) {
852
		torture_shutdown_absorb("rcu_torture_boost");
853
		schedule_timeout_uninterruptible(1);
854
	}
855
	destroy_rcu_head_on_stack(&rbi.rcu);
856
	torture_kthread_stopping("rcu_torture_boost");
857 858 859
	return 0;
}

860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887
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");
888
		goto wait_for_stop;
889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905
	}
	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());
906
	vfree(rhp);
907
wait_for_stop:
908 909 910 911
	torture_kthread_stopping("rcu_torture_cbflood");
	return 0;
}

912 913 914 915 916 917 918 919 920 921 922
/*
 * 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;

923
	VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
924 925
	do {
		fqs_resume_time = jiffies + fqs_stutter * HZ;
926 927
		while (ULONG_CMP_LT(jiffies, fqs_resume_time) &&
		       !kthread_should_stop()) {
928 929 930
			schedule_timeout_interruptible(1);
		}
		fqs_burst_remaining = fqs_duration;
931 932
		while (fqs_burst_remaining > 0 &&
		       !kthread_should_stop()) {
933 934 935 936
			cur_ops->fqs();
			udelay(fqs_holdoff);
			fqs_burst_remaining -= fqs_holdoff;
		}
937
		stutter_wait("rcu_torture_fqs");
938
	} while (!torture_must_stop());
939
	torture_kthread_stopping("rcu_torture_fqs");
940 941 942
	return 0;
}

943 944 945 946 947 948 949 950
/*
 * 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)
{
951
	bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
952
	int expediting = 0;
953 954
	unsigned long gp_snap;
	bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal;
955
	bool gp_sync1 = gp_sync;
956 957 958
	int i;
	struct rcu_torture *rp;
	struct rcu_torture *old_rp;
959
	static DEFINE_TORTURE_RANDOM(rand);
960 961
	int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC,
			   RTWS_COND_GET, RTWS_SYNC };
962
	int nsynctypes = 0;
963

964
	VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
965 966
	if (!can_expedite) {
		pr_alert("%s" TORTURE_FLAG
967
			 " GP expediting controlled from boot/sysfs for %s,\n",
968 969 970 971 972
			 torture_type, cur_ops->name);
		pr_alert("%s" TORTURE_FLAG
			 " Disabled dynamic grace-period expediting.\n",
			 torture_type);
	}
973

974
	/* Initialize synctype[] array.  If none set, take default. */
975
	if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync1)
976
		gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true;
977 978 979 980 981 982 983 984 985 986 987 988
	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");
989 990 991 992
	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");
993 994
	if (WARN_ONCE(nsynctypes == 0,
		      "rcu_torture_writer: No update-side primitives.\n")) {
995 996 997 998 999
		/*
		 * No updates primitives, so don't try updating.
		 * The resulting test won't be testing much, hence the
		 * above WARN_ONCE().
		 */
1000 1001 1002 1003
		rcu_torture_writer_state = RTWS_STOPPING;
		torture_kthread_stopping("rcu_torture_writer");
	}

1004
	do {
1005
		rcu_torture_writer_state = RTWS_FIXED_DELAY;
1006
		schedule_timeout_uninterruptible(1);
1007 1008
		rp = rcu_torture_alloc();
		if (rp == NULL)
1009 1010
			continue;
		rp->rtort_pipe_count = 0;
1011
		rcu_torture_writer_state = RTWS_DELAY;
1012
		udelay(torture_random(&rand) & 0x3ff);
1013
		rcu_torture_writer_state = RTWS_REPLACE;
1014 1015
		old_rp = rcu_dereference_check(rcu_torture_current,
					       current == writer_task);
1016
		rp->rtort_mbtest = 1;
1017
		rcu_assign_pointer(rcu_torture_current, rp);
1018
		smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
1019
		if (old_rp) {
1020 1021 1022 1023 1024
			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++;
1025 1026
			switch (synctype[torture_random(&rand) % nsynctypes]) {
			case RTWS_DEF_FREE:
1027
				rcu_torture_writer_state = RTWS_DEF_FREE;
1028
				cur_ops->deferred_free(old_rp);
1029 1030
				break;
			case RTWS_EXP_SYNC:
1031
				rcu_torture_writer_state = RTWS_EXP_SYNC;
1032
				cur_ops->exp_sync();
1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045
				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;
1046 1047 1048 1049 1050
			case RTWS_SYNC:
				rcu_torture_writer_state = RTWS_SYNC;
				cur_ops->sync();
				rcu_torture_pipe_update(old_rp);
				break;
1051 1052 1053
			default:
				WARN_ON_ONCE(1);
				break;
1054
			}
1055
		}
1056
		rcutorture_record_progress(++rcu_torture_current_version);
1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067
		/* 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;
		}
1068
		rcu_torture_writer_state = RTWS_STUTTER;
1069
		stutter_wait("rcu_torture_writer");
1070
	} while (!torture_must_stop());
1071 1072 1073 1074 1075 1076
	/* 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());
1077
	rcu_torture_writer_state = RTWS_STOPPING;
1078
	torture_kthread_stopping("rcu_torture_writer");
1079 1080 1081
	return 0;
}

1082 1083 1084 1085 1086 1087 1088
/*
 * RCU torture fake writer kthread.  Repeatedly calls sync, with a random
 * delay between calls.
 */
static int
rcu_torture_fakewriter(void *arg)
{
1089
	DEFINE_TORTURE_RANDOM(rand);
1090

1091
	VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1092
	set_user_nice(current, MAX_NICE);
1093 1094

	do {
1095 1096
		schedule_timeout_uninterruptible(1 + torture_random(&rand)%10);
		udelay(torture_random(&rand) & 0x3ff);
1097
		if (cur_ops->cb_barrier != NULL &&
1098
		    torture_random(&rand) % (nfakewriters * 8) == 0) {
1099
			cur_ops->cb_barrier();
1100
		} else if (gp_normal == gp_exp) {
1101
			if (torture_random(&rand) & 0x80)
1102 1103 1104 1105
				cur_ops->sync();
			else
				cur_ops->exp_sync();
		} else if (gp_normal) {
1106
			cur_ops->sync();
1107 1108 1109
		} else {
			cur_ops->exp_sync();
		}
1110
		stutter_wait("rcu_torture_fakewriter");
1111
	} while (!torture_must_stop());
1112

1113
	torture_kthread_stopping("rcu_torture_fakewriter");
1114 1115 1116
	return 0;
}

1117 1118 1119 1120 1121 1122 1123 1124 1125
/*
 * 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;
1126
	unsigned long started;
1127
	unsigned long completed;
1128
	static DEFINE_TORTURE_RANDOM(rand);
1129 1130 1131
	static DEFINE_SPINLOCK(rand_lock);
	struct rcu_torture *p;
	int pipe_count;
1132
	unsigned long long ts;
1133 1134

	idx = cur_ops->readlock();
1135 1136 1137 1138
	if (cur_ops->started)
		started = cur_ops->started();
	else
		started = cur_ops->completed();
1139
	ts = rcu_trace_clock_local();
1140 1141 1142
	p = rcu_dereference_check(rcu_torture_current,
				  rcu_read_lock_bh_held() ||
				  rcu_read_lock_sched_held() ||
1143 1144
				  srcu_read_lock_held(srcu_ctlp) ||
				  torturing_tasks());
1145 1146 1147 1148 1149 1150 1151 1152
	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);
1153
	cur_ops->read_delay(&rand);
1154 1155 1156 1157 1158 1159 1160 1161
	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;
	}
1162
	completed = cur_ops->completed();
1163 1164
	if (pipe_count > 1) {
		do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, ts,
1165
					  started, completed);
1166
		rcu_ftrace_dump(DUMP_ALL);
1167
	}
R
Rusty Russell 已提交
1168
	__this_cpu_inc(rcu_torture_count[pipe_count]);
1169 1170 1171
	completed = completed - started;
	if (cur_ops->started)
		completed++;
1172 1173 1174 1175
	if (completed > RCU_TORTURE_PIPE_LEN) {
		/* Should not happen, but... */
		completed = RCU_TORTURE_PIPE_LEN;
	}
R
Rusty Russell 已提交
1176
	__this_cpu_inc(rcu_torture_batch[completed]);
1177 1178 1179 1180
	preempt_enable();
	cur_ops->readunlock(idx);
}

1181 1182 1183 1184 1185 1186 1187 1188 1189
/*
 * 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)
{
1190
	unsigned long started;
1191
	unsigned long completed;
1192
	int idx;
1193
	DEFINE_TORTURE_RANDOM(rand);
1194 1195
	struct rcu_torture *p;
	int pipe_count;
1196
	struct timer_list t;
1197
	unsigned long long ts;
1198

1199
	VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
1200
	set_user_nice(current, MAX_NICE);
1201
	if (irqreader && cur_ops->irq_capable)
1202
		setup_timer_on_stack(&t, rcu_torture_timer, 0);
1203

1204
	do {
1205
		if (irqreader && cur_ops->irq_capable) {
1206
			if (!timer_pending(&t))
1207
				mod_timer(&t, jiffies + 1);
1208
		}
1209
		idx = cur_ops->readlock();
1210 1211 1212 1213
		if (cur_ops->started)
			started = cur_ops->started();
		else
			started = cur_ops->completed();
1214
		ts = rcu_trace_clock_local();
1215 1216 1217
		p = rcu_dereference_check(rcu_torture_current,
					  rcu_read_lock_bh_held() ||
					  rcu_read_lock_sched_held() ||
1218 1219
					  srcu_read_lock_held(srcu_ctlp) ||
					  torturing_tasks());
1220 1221
		if (p == NULL) {
			/* Wait for rcu_torture_writer to get underway */
1222
			cur_ops->readunlock(idx);
1223 1224 1225
			schedule_timeout_interruptible(HZ);
			continue;
		}
1226 1227
		if (p->rtort_mbtest == 0)
			atomic_inc(&n_rcu_torture_mberror);
1228
		cur_ops->read_delay(&rand);
1229 1230 1231 1232 1233 1234
		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;
		}
1235
		completed = cur_ops->completed();
1236 1237
		if (pipe_count > 1) {
			do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
1238
						  ts, started, completed);
1239
			rcu_ftrace_dump(DUMP_ALL);
1240
		}
R
Rusty Russell 已提交
1241
		__this_cpu_inc(rcu_torture_count[pipe_count]);
1242 1243 1244
		completed = completed - started;
		if (cur_ops->started)
			completed++;
1245 1246 1247 1248
		if (completed > RCU_TORTURE_PIPE_LEN) {
			/* Should not happen, but... */
			completed = RCU_TORTURE_PIPE_LEN;
		}
R
Rusty Russell 已提交
1249
		__this_cpu_inc(rcu_torture_batch[completed]);
1250
		preempt_enable();
1251
		cur_ops->readunlock(idx);
1252
		stutter_wait("rcu_torture_reader");
1253
	} while (!torture_must_stop());
1254
	if (irqreader && cur_ops->irq_capable) {
1255
		del_timer_sync(&t);
1256 1257
		destroy_timer_on_stack(&t);
	}
1258
	torture_kthread_stopping("rcu_torture_reader");
1259 1260 1261 1262
	return 0;
}

/*
1263 1264 1265 1266 1267 1268
 * 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).
1269
 */
1270
static void
1271
rcu_torture_stats_print(void)
1272 1273 1274 1275 1276
{
	int cpu;
	int i;
	long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
	long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1277
	static unsigned long rtcv_snap = ULONG_MAX;
1278
	struct task_struct *wtp;
1279

1280
	for_each_possible_cpu(cpu) {
1281 1282 1283 1284 1285 1286 1287 1288 1289
		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;
	}
1290 1291 1292 1293 1294 1295 1296 1297 1298

	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));
1299
	pr_cont("rtmbe: %d rtbe: %ld rtbke: %ld rtbre: %ld ",
1300
		atomic_read(&n_rcu_torture_mberror),
1301
		n_rcu_torture_barrier_error,
1302 1303 1304 1305 1306 1307 1308
		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();
1309
	pr_cont("barrier: %ld/%ld:%ld ",
1310 1311 1312
		n_barrier_successes,
		n_barrier_attempts,
		n_rcu_torture_barrier_error);
1313
	pr_cont("cbflood: %ld\n", atomic_long_read(&n_cbfloods));
1314 1315

	pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1316
	if (atomic_read(&n_rcu_torture_mberror) != 0 ||
1317
	    n_rcu_torture_barrier_error != 0 ||
1318 1319
	    n_rcu_torture_boost_ktrerror != 0 ||
	    n_rcu_torture_boost_rterror != 0 ||
1320 1321
	    n_rcu_torture_boost_failure != 0 ||
	    i > 1) {
1322
		pr_cont("%s", "!!! ");
1323
		atomic_inc(&n_rcu_torture_error);
1324
		WARN_ON_ONCE(1);
1325
	}
1326
	pr_cont("Reader Pipe: ");
1327
	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1328 1329 1330 1331 1332
		pr_cont(" %ld", pipesummary[i]);
	pr_cont("\n");

	pr_alert("%s%s ", torture_type, TORTURE_FLAG);
	pr_cont("Reader Batch: ");
1333
	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1334 1335 1336 1337 1338
		pr_cont(" %ld", batchsummary[i]);
	pr_cont("\n");

	pr_alert("%s%s ", torture_type, TORTURE_FLAG);
	pr_cont("Free-Block Circulation: ");
1339
	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1340
		pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
1341
	}
1342 1343
	pr_cont("\n");

1344
	if (cur_ops->stats)
1345
		cur_ops->stats();
1346 1347
	if (rtcv_snap == rcu_torture_current_version &&
	    rcu_torture_current != NULL) {
1348 1349 1350
		int __maybe_unused flags = 0;
		unsigned long __maybe_unused gpnum = 0;
		unsigned long __maybe_unused completed = 0;
1351 1352 1353

		rcutorture_get_gp_data(cur_ops->ttype,
				       &flags, &gpnum, &completed);
1354 1355
		srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp,
					&flags, &gpnum, &completed);
1356 1357
		wtp = READ_ONCE(writer_task);
		pr_alert("??? Writer stall state %s(%d) g%lu c%lu f%#x ->state %#lx\n",
1358
			 rcu_torture_writer_state_getname(),
1359
			 rcu_torture_writer_state,
1360 1361
			 gpnum, completed, flags,
			 wtp == NULL ? ~0UL : wtp->state);
1362
		show_rcu_gp_kthreads();
1363
		rcu_ftrace_dump(DUMP_ALL);
1364 1365
	}
	rtcv_snap = rcu_torture_current_version;
1366 1367 1368 1369 1370 1371 1372 1373 1374
}

/*
 * Periodically prints torture statistics, if periodic statistics printing
 * was specified via the stat_interval module parameter.
 */
static int
rcu_torture_stats(void *arg)
{
1375
	VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1376 1377 1378
	do {
		schedule_timeout_interruptible(stat_interval * HZ);
		rcu_torture_stats_print();
1379
		torture_shutdown_absorb("rcu_torture_stats");
1380
	} while (!torture_must_stop());
1381
	torture_kthread_stopping("rcu_torture_stats");
1382 1383 1384
	return 0;
}

1385
static inline void
1386
rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1387
{
1388 1389 1390 1391 1392 1393 1394
	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 "
1395 1396
		 "stall_cpu=%d stall_cpu_holdoff=%d "
		 "n_barrier_cbs=%d "
1397 1398 1399 1400 1401 1402
		 "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,
1403 1404
		 stall_cpu, stall_cpu_holdoff,
		 n_barrier_cbs,
1405
		 onoff_interval, onoff_holdoff);
1406 1407
}

1408
static int rcutorture_booster_cleanup(unsigned int cpu)
1409 1410 1411 1412
{
	struct task_struct *t;

	if (boost_tasks[cpu] == NULL)
1413
		return 0;
1414 1415 1416 1417 1418 1419
	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! */
1420
	torture_stop_kthread(rcu_torture_boost, t);
1421
	return 0;
1422 1423
}

1424
static int rcutorture_booster_init(unsigned int cpu)
1425 1426 1427 1428 1429 1430 1431 1432
{
	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);
1433
	VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
E
Eric Dumazet 已提交
1434 1435 1436
	boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
						  cpu_to_node(cpu),
						  "rcu_torture_boost");
1437 1438
	if (IS_ERR(boost_tasks[cpu])) {
		retval = PTR_ERR(boost_tasks[cpu]);
1439
		VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450
		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;
}

1451 1452 1453 1454
/*
 * CPU-stall kthread.  It waits as specified by stall_cpu_holdoff, then
 * induces a CPU stall for the time specified by stall_cpu.
 */
1455
static int rcu_torture_stall(void *args)
1456 1457 1458
{
	unsigned long stop_at;

1459
	VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
1460
	if (stall_cpu_holdoff > 0) {
1461
		VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
1462
		schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
1463
		VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
1464 1465 1466 1467
	}
	if (!kthread_should_stop()) {
		stop_at = get_seconds() + stall_cpu;
		/* RCU CPU stall is expected behavior in following code. */
1468
		pr_alert("rcu_torture_stall start.\n");
1469 1470 1471 1472 1473 1474
		rcu_read_lock();
		preempt_disable();
		while (ULONG_CMP_LT(get_seconds(), stop_at))
			continue;  /* Induce RCU CPU stall warning. */
		preempt_enable();
		rcu_read_unlock();
1475
		pr_alert("rcu_torture_stall end.\n");
1476
	}
1477
	torture_shutdown_absorb("rcu_torture_stall");
1478 1479 1480 1481 1482 1483 1484 1485 1486 1487
	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;
1488
	return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
1489 1490
}

1491
/* Callback function for RCU barrier testing. */
1492
static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
1493 1494 1495 1496 1497 1498 1499 1500
{
	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;
1501
	bool lastphase = 0;
1502
	bool newphase;
1503 1504 1505
	struct rcu_head rcu;

	init_rcu_head_on_stack(&rcu);
1506
	VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
1507
	set_user_nice(current, MAX_NICE);
1508 1509
	do {
		wait_event(barrier_cbs_wq[myid],
1510
			   (newphase =
1511
			    smp_load_acquire(&barrier_phase)) != lastphase ||
1512
			   torture_must_stop());
1513
		lastphase = newphase;
1514
		if (torture_must_stop())
1515
			break;
1516 1517
		/*
		 * The above smp_load_acquire() ensures barrier_phase load
P
Paul E. McKenney 已提交
1518
		 * is ordered before the following ->call().
1519
		 */
1520
		local_irq_disable(); /* Just to test no-irq call_rcu(). */
1521
		cur_ops->call(&rcu, rcu_torture_barrier_cbf);
1522
		local_irq_enable();
1523 1524
		if (atomic_dec_and_test(&barrier_cbs_count))
			wake_up(&barrier_wq);
1525
	} while (!torture_must_stop());
1526 1527
	if (cur_ops->cb_barrier != NULL)
		cur_ops->cb_barrier();
1528
	destroy_rcu_head_on_stack(&rcu);
1529
	torture_kthread_stopping("rcu_torture_barrier_cbs");
1530 1531 1532 1533 1534 1535 1536 1537
	return 0;
}

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

1538
	VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
1539 1540 1541
	do {
		atomic_set(&barrier_cbs_invoked, 0);
		atomic_set(&barrier_cbs_count, n_barrier_cbs);
1542 1543
		/* Ensure barrier_phase ordered after prior assignments. */
		smp_store_release(&barrier_phase, !barrier_phase);
1544 1545 1546 1547
		for (i = 0; i < n_barrier_cbs; i++)
			wake_up(&barrier_cbs_wq[i]);
		wait_event(barrier_wq,
			   atomic_read(&barrier_cbs_count) == 0 ||
1548 1549
			   torture_must_stop());
		if (torture_must_stop())
1550 1551
			break;
		n_barrier_attempts++;
1552
		cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
1553 1554
		if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
			n_rcu_torture_barrier_error++;
1555 1556 1557
			pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
			       atomic_read(&barrier_cbs_invoked),
			       n_barrier_cbs);
1558 1559 1560 1561
			WARN_ON_ONCE(1);
		}
		n_barrier_successes++;
		schedule_timeout_interruptible(HZ / 10);
1562
	} while (!torture_must_stop());
1563
	torture_kthread_stopping("rcu_torture_barrier");
1564 1565 1566 1567 1568 1569 1570 1571 1572
	return 0;
}

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

1573
	if (n_barrier_cbs <= 0)
1574 1575
		return 0;
	if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
1576 1577 1578 1579 1580 1581
		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);
1582 1583 1584 1585 1586 1587 1588 1589 1590 1591
		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);
1592
	if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
1593 1594 1595
		return -ENOMEM;
	for (i = 0; i < n_barrier_cbs; i++) {
		init_waitqueue_head(&barrier_cbs_wq[i]);
1596 1597 1598 1599
		ret = torture_create_kthread(rcu_torture_barrier_cbs,
					     (void *)(long)i,
					     barrier_cbs_tasks[i]);
		if (ret)
1600 1601
			return ret;
	}
1602
	return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
1603 1604 1605 1606 1607 1608 1609
}

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

1610
	torture_stop_kthread(rcu_torture_barrier, barrier_task);
1611
	if (barrier_cbs_tasks != NULL) {
1612 1613 1614
		for (i = 0; i < n_barrier_cbs; i++)
			torture_stop_kthread(rcu_torture_barrier_cbs,
					     barrier_cbs_tasks[i]);
1615 1616 1617 1618 1619 1620 1621 1622 1623
		kfree(barrier_cbs_tasks);
		barrier_cbs_tasks = NULL;
	}
	if (barrier_cbs_wq != NULL) {
		kfree(barrier_cbs_wq);
		barrier_cbs_wq = NULL;
	}
}

1624
static enum cpuhp_state rcutor_hp;
1625

1626 1627 1628 1629 1630
static void
rcu_torture_cleanup(void)
{
	int i;

1631
	rcutorture_record_test_transition();
1632
	if (torture_cleanup_begin()) {
1633 1634 1635 1636
		if (cur_ops->cb_barrier != NULL)
			cur_ops->cb_barrier();
		return;
	}
1637

1638
	rcu_torture_barrier_cleanup();
1639 1640
	torture_stop_kthread(rcu_torture_stall, stall_task);
	torture_stop_kthread(rcu_torture_writer, writer_task);
1641

1642
	if (reader_tasks) {
1643 1644 1645
		for (i = 0; i < nrealreaders; i++)
			torture_stop_kthread(rcu_torture_reader,
					     reader_tasks[i]);
1646 1647 1648 1649
		kfree(reader_tasks);
	}
	rcu_torture_current = NULL;

1650
	if (fakewriter_tasks) {
1651
		for (i = 0; i < nfakewriters; i++) {
1652 1653
			torture_stop_kthread(rcu_torture_fakewriter,
					     fakewriter_tasks[i]);
1654 1655 1656 1657 1658
		}
		kfree(fakewriter_tasks);
		fakewriter_tasks = NULL;
	}

1659 1660
	torture_stop_kthread(rcu_torture_stats, stats_task);
	torture_stop_kthread(rcu_torture_fqs, fqs_task);
1661 1662
	for (i = 0; i < ncbflooders; i++)
		torture_stop_kthread(rcu_torture_cbflood, cbflood_task[i]);
1663
	if ((test_boost == 1 && cur_ops->can_boost) ||
1664 1665
	    test_boost == 2)
		cpuhp_remove_state(rcutor_hp);
1666

1667 1668 1669 1670
	/*
	 * Wait for all RCU callbacks to fire, then do flavor-specific
	 * cleanup operations.
	 */
1671 1672
	if (cur_ops->cb_barrier != NULL)
		cur_ops->cb_barrier();
1673 1674
	if (cur_ops->cleanup != NULL)
		cur_ops->cleanup();
1675 1676

	rcu_torture_stats_print();  /* -After- the stats thread is stopped! */
1677

1678
	if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
1679
		rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
1680
	else if (torture_onoff_failures())
1681 1682
		rcu_torture_print_module_parms(cur_ops,
					       "End of test: RCU_HOTPLUG");
1683
	else
1684
		rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
1685
	torture_cleanup_end();
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 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743
#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 */
}

1744
static int __init
1745 1746 1747 1748 1749
rcu_torture_init(void)
{
	int i;
	int cpu;
	int firsterr = 0;
1750
	static struct rcu_torture_ops *torture_ops[] = {
1751 1752
		&rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops,
		&sched_ops, RCUTORTURE_TASKS_OPS
1753
	};
1754

1755
	if (!torture_init_begin(torture_type, verbose, &torture_runnable))
1756
		return -EBUSY;
1757

1758
	/* Process args and tell the world that the torturer is on the job. */
1759
	for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1760
		cur_ops = torture_ops[i];
1761
		if (strcmp(torture_type, cur_ops->name) == 0)
1762 1763
			break;
	}
1764
	if (i == ARRAY_SIZE(torture_ops)) {
1765 1766 1767
		pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
			 torture_type);
		pr_alert("rcu-torture types:");
1768
		for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1769 1770
			pr_alert(" %s", torture_ops[i]->name);
		pr_alert("\n");
1771 1772
		firsterr = -EINVAL;
		goto unwind;
1773
	}
1774
	if (cur_ops->fqs == NULL && fqs_duration != 0) {
1775
		pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
1776 1777
		fqs_duration = 0;
	}
1778
	if (cur_ops->init)
1779
		cur_ops->init();
1780

1781
	if (nreaders >= 0) {
1782
		nrealreaders = nreaders;
1783
	} else {
1784
		nrealreaders = num_online_cpus() - 2 - nreaders;
1785 1786 1787
		if (nrealreaders <= 0)
			nrealreaders = 1;
	}
1788
	rcu_torture_print_module_parms(cur_ops, "Start of test");
1789 1790 1791 1792

	/* Set up the freelist. */

	INIT_LIST_HEAD(&rcu_torture_freelist);
1793
	for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1794
		rcu_tortures[i].rtort_mbtest = 0;
1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805
		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);
1806 1807
	atomic_set(&n_rcu_torture_mberror, 0);
	atomic_set(&n_rcu_torture_error, 0);
1808
	n_rcu_torture_barrier_error = 0;
1809 1810 1811 1812
	n_rcu_torture_boost_ktrerror = 0;
	n_rcu_torture_boost_rterror = 0;
	n_rcu_torture_boost_failure = 0;
	n_rcu_torture_boosts = 0;
1813 1814
	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
		atomic_set(&rcu_torture_wcount[i], 0);
1815
	for_each_possible_cpu(cpu) {
1816 1817 1818 1819 1820 1821 1822 1823
		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. */

1824 1825 1826
	firsterr = torture_create_kthread(rcu_torture_writer, NULL,
					  writer_task);
	if (firsterr)
1827
		goto unwind;
1828 1829 1830 1831 1832 1833 1834 1835 1836
	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;
		}
1837 1838
	}
	for (i = 0; i < nfakewriters; i++) {
1839 1840 1841
		firsterr = torture_create_kthread(rcu_torture_fakewriter,
						  NULL, fakewriter_tasks[i]);
		if (firsterr)
1842 1843
			goto unwind;
	}
1844
	reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
1845 1846
			       GFP_KERNEL);
	if (reader_tasks == NULL) {
1847
		VERBOSE_TOROUT_ERRSTRING("out of memory");
1848 1849 1850 1851
		firsterr = -ENOMEM;
		goto unwind;
	}
	for (i = 0; i < nrealreaders; i++) {
1852 1853 1854
		firsterr = torture_create_kthread(rcu_torture_reader, NULL,
						  reader_tasks[i]);
		if (firsterr)
1855 1856 1857
			goto unwind;
	}
	if (stat_interval > 0) {
1858 1859 1860
		firsterr = torture_create_kthread(rcu_torture_stats, NULL,
						  stats_task);
		if (firsterr)
1861 1862
			goto unwind;
	}
1863
	if (test_no_idle_hz && shuffle_interval > 0) {
1864 1865
		firsterr = torture_shuffle_init(shuffle_interval * HZ);
		if (firsterr)
1866 1867
			goto unwind;
	}
1868 1869 1870
	if (stutter < 0)
		stutter = 0;
	if (stutter) {
1871 1872
		firsterr = torture_stutter_init(stutter * HZ);
		if (firsterr)
1873 1874
			goto unwind;
	}
1875 1876 1877
	if (fqs_duration < 0)
		fqs_duration = 0;
	if (fqs_duration) {
1878
		/* Create the fqs thread */
1879 1880
		firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
						  fqs_task);
1881
		if (firsterr)
1882 1883
			goto unwind;
	}
1884 1885 1886 1887 1888 1889 1890 1891
	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;
1892 1893 1894 1895 1896 1897 1898

		firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE",
					     rcutorture_booster_init,
					     rcutorture_booster_cleanup);
		if (firsterr < 0)
			goto unwind;
		rcutor_hp = firsterr;
1899
	}
1900 1901
	firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
	if (firsterr)
1902
		goto unwind;
1903 1904
	firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval * HZ);
	if (firsterr)
1905
		goto unwind;
1906 1907
	firsterr = rcu_torture_stall_init();
	if (firsterr)
1908
		goto unwind;
1909 1910
	firsterr = rcu_torture_barrier_init();
	if (firsterr)
1911
		goto unwind;
1912 1913
	if (object_debug)
		rcu_test_debug_objects();
1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931
	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;
		}
	}
1932
	rcutorture_record_test_transition();
1933
	torture_init_end();
1934 1935 1936
	return 0;

unwind:
1937
	torture_init_end();
1938 1939 1940 1941 1942 1943
	rcu_torture_cleanup();
	return firsterr;
}

module_init(rcu_torture_init);
module_exit(rcu_torture_cleanup);