rcutorture.c 54.2 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>
#include <linux/sched.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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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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{
	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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		unsigned long l0, l1;
		unsigned long u0, u1;
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		long c0, c1;
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		struct srcu_array *counts = per_cpu_ptr(srcu_ctlp->per_cpu_ref, cpu);
572

573 574 575 576 577 578 579 580 581 582 583 584 585 586
		u0 = counts->unlock_count[!idx];
		u1 = counts->unlock_count[idx];

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

		l0 = counts->lock_count[!idx];
		l1 = counts->lock_count[idx];

		c0 = l0 - u0;
		c1 = l1 - u1;
587
		pr_cont(" %d(%ld,%ld)", cpu, c0, c1);
588
	}
589
	pr_cont("\n");
590 591
}

592 593
static void srcu_torture_synchronize_expedited(void)
{
594
	synchronize_srcu_expedited(srcu_ctlp);
595 596
}

597
static struct rcu_torture_ops srcu_ops = {
598
	.ttype		= SRCU_FLAVOR,
599
	.init		= rcu_sync_torture_init,
600 601 602
	.readlock	= srcu_torture_read_lock,
	.read_delay	= srcu_read_delay,
	.readunlock	= srcu_torture_read_unlock,
603
	.started	= NULL,
604
	.completed	= srcu_torture_completed,
605
	.deferred_free	= srcu_torture_deferred_free,
606
	.sync		= srcu_torture_synchronize,
607
	.exp_sync	= srcu_torture_synchronize_expedited,
608 609
	.call		= srcu_torture_call,
	.cb_barrier	= srcu_torture_barrier,
610 611
	.stats		= srcu_torture_stats,
	.name		= "srcu"
612 613
};

614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645
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"
};

646 647 648 649 650 651 652 653 654 655 656 657 658 659 660
/*
 * 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();
}

661 662 663 664 665
static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
{
	call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
}

666
static struct rcu_torture_ops sched_ops = {
667
	.ttype		= RCU_SCHED_FLAVOR,
668 669 670 671
	.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,
672
	.started	= rcu_batches_started_sched,
673
	.completed	= rcu_batches_completed_sched,
674
	.deferred_free	= rcu_sched_torture_deferred_free,
675
	.sync		= synchronize_sched,
676
	.exp_sync	= synchronize_sched_expedited,
677 678
	.get_state	= get_state_synchronize_sched,
	.cond_sync	= cond_synchronize_sched,
679
	.call		= call_rcu_sched,
680
	.cb_barrier	= rcu_barrier_sched,
681
	.fqs		= rcu_sched_force_quiescent_state,
682 683 684
	.stats		= NULL,
	.irq_capable	= 1,
	.name		= "sched"
685 686
};

687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712
#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,
713
	.started	= rcu_no_completed,
714 715 716 717 718 719 720 721 722 723 724 725 726 727
	.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,

728 729 730 731 732
static bool __maybe_unused torturing_tasks(void)
{
	return cur_ops == &tasks_ops;
}

733 734 735 736
#else /* #ifdef CONFIG_TASKS_RCU */

#define RCUTORTURE_TASKS_OPS

737
static bool __maybe_unused torturing_tasks(void)
738 739 740 741
{
	return false;
}

742 743
#endif /* #else #ifdef CONFIG_TASKS_RCU */

744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760
/*
 * 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);

761 762
	/* Ensure RCU-core accesses precede clearing ->inflight */
	smp_store_release(&rbip->inflight, 0);
763 764 765 766 767 768 769 770 771 772
}

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;

773
	VERBOSE_TOROUT_STRING("rcu_torture_boost started");
774 775 776 777

	/* Set real-time priority. */
	sp.sched_priority = 1;
	if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
778
		VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!");
779 780 781
		n_rcu_torture_boost_rterror++;
	}

782
	init_rcu_head_on_stack(&rbi.rcu);
783 784 785 786
	/* Each pass through the following loop does one boost-test cycle. */
	do {
		/* Wait for the next test interval. */
		oldstarttime = boost_starttime;
787
		while (ULONG_CMP_LT(jiffies, oldstarttime)) {
788
			schedule_timeout_interruptible(oldstarttime - jiffies);
789
			stutter_wait("rcu_torture_boost");
790
			if (torture_must_stop())
791 792 793 794 795 796
				goto checkwait;
		}

		/* Do one boost-test interval. */
		endtime = oldstarttime + test_boost_duration * HZ;
		call_rcu_time = jiffies;
797
		while (ULONG_CMP_LT(jiffies, endtime)) {
798
			/* If we don't have a callback in flight, post one. */
799 800 801
			if (!smp_load_acquire(&rbi.inflight)) {
				/* RCU core before ->inflight = 1. */
				smp_store_release(&rbi.inflight, 1);
802 803 804
				call_rcu(&rbi.rcu, rcu_torture_boost_cb);
				if (jiffies - call_rcu_time >
					 test_boost_duration * HZ - HZ / 2) {
805
					VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
806 807 808 809
					n_rcu_torture_boost_failure++;
				}
				call_rcu_time = jiffies;
			}
810
			stutter_wait("rcu_torture_boost");
811
			if (torture_must_stop())
812 813 814 815 816 817 818 819 820 821
				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.
		 */
822 823
		while (oldstarttime == boost_starttime &&
		       !kthread_should_stop()) {
824 825 826 827 828 829 830 831 832 833 834
			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. */
835
checkwait:	stutter_wait("rcu_torture_boost");
836
	} while (!torture_must_stop());
837 838

	/* Clean up and exit. */
839
	while (!kthread_should_stop() || smp_load_acquire(&rbi.inflight)) {
840
		torture_shutdown_absorb("rcu_torture_boost");
841
		schedule_timeout_uninterruptible(1);
842
	}
843
	destroy_rcu_head_on_stack(&rbi.rcu);
844
	torture_kthread_stopping("rcu_torture_boost");
845 846 847
	return 0;
}

848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875
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");
876
		goto wait_for_stop;
877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893
	}
	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());
894
	vfree(rhp);
895
wait_for_stop:
896 897 898 899
	torture_kthread_stopping("rcu_torture_cbflood");
	return 0;
}

900 901 902 903 904 905 906 907 908 909 910
/*
 * 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;

911
	VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
912 913
	do {
		fqs_resume_time = jiffies + fqs_stutter * HZ;
914 915
		while (ULONG_CMP_LT(jiffies, fqs_resume_time) &&
		       !kthread_should_stop()) {
916 917 918
			schedule_timeout_interruptible(1);
		}
		fqs_burst_remaining = fqs_duration;
919 920
		while (fqs_burst_remaining > 0 &&
		       !kthread_should_stop()) {
921 922 923 924
			cur_ops->fqs();
			udelay(fqs_holdoff);
			fqs_burst_remaining -= fqs_holdoff;
		}
925
		stutter_wait("rcu_torture_fqs");
926
	} while (!torture_must_stop());
927
	torture_kthread_stopping("rcu_torture_fqs");
928 929 930
	return 0;
}

931 932 933 934 935 936 937 938
/*
 * 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)
{
939
	bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
940
	int expediting = 0;
941 942
	unsigned long gp_snap;
	bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal;
943
	bool gp_sync1 = gp_sync;
944 945 946
	int i;
	struct rcu_torture *rp;
	struct rcu_torture *old_rp;
947
	static DEFINE_TORTURE_RANDOM(rand);
948 949
	int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC,
			   RTWS_COND_GET, RTWS_SYNC };
950
	int nsynctypes = 0;
951

952
	VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
953 954
	if (!can_expedite) {
		pr_alert("%s" TORTURE_FLAG
955
			 " GP expediting controlled from boot/sysfs for %s,\n",
956 957 958 959 960
			 torture_type, cur_ops->name);
		pr_alert("%s" TORTURE_FLAG
			 " Disabled dynamic grace-period expediting.\n",
			 torture_type);
	}
961

962
	/* Initialize synctype[] array.  If none set, take default. */
963
	if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync1)
964
		gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true;
965 966 967 968 969 970 971 972 973 974 975 976
	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");
977 978 979 980
	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");
981 982
	if (WARN_ONCE(nsynctypes == 0,
		      "rcu_torture_writer: No update-side primitives.\n")) {
983 984 985 986 987
		/*
		 * No updates primitives, so don't try updating.
		 * The resulting test won't be testing much, hence the
		 * above WARN_ONCE().
		 */
988 989 990 991
		rcu_torture_writer_state = RTWS_STOPPING;
		torture_kthread_stopping("rcu_torture_writer");
	}

992
	do {
993
		rcu_torture_writer_state = RTWS_FIXED_DELAY;
994
		schedule_timeout_uninterruptible(1);
995 996
		rp = rcu_torture_alloc();
		if (rp == NULL)
997 998
			continue;
		rp->rtort_pipe_count = 0;
999
		rcu_torture_writer_state = RTWS_DELAY;
1000
		udelay(torture_random(&rand) & 0x3ff);
1001
		rcu_torture_writer_state = RTWS_REPLACE;
1002 1003
		old_rp = rcu_dereference_check(rcu_torture_current,
					       current == writer_task);
1004
		rp->rtort_mbtest = 1;
1005
		rcu_assign_pointer(rcu_torture_current, rp);
1006
		smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
1007
		if (old_rp) {
1008 1009 1010 1011 1012
			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++;
1013 1014
			switch (synctype[torture_random(&rand) % nsynctypes]) {
			case RTWS_DEF_FREE:
1015
				rcu_torture_writer_state = RTWS_DEF_FREE;
1016
				cur_ops->deferred_free(old_rp);
1017 1018
				break;
			case RTWS_EXP_SYNC:
1019
				rcu_torture_writer_state = RTWS_EXP_SYNC;
1020
				cur_ops->exp_sync();
1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033
				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;
1034 1035 1036 1037 1038
			case RTWS_SYNC:
				rcu_torture_writer_state = RTWS_SYNC;
				cur_ops->sync();
				rcu_torture_pipe_update(old_rp);
				break;
1039 1040 1041
			default:
				WARN_ON_ONCE(1);
				break;
1042
			}
1043
		}
1044
		rcutorture_record_progress(++rcu_torture_current_version);
1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055
		/* 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;
		}
1056
		rcu_torture_writer_state = RTWS_STUTTER;
1057
		stutter_wait("rcu_torture_writer");
1058
	} while (!torture_must_stop());
1059 1060 1061 1062 1063 1064
	/* 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());
1065
	rcu_torture_writer_state = RTWS_STOPPING;
1066
	torture_kthread_stopping("rcu_torture_writer");
1067 1068 1069
	return 0;
}

1070 1071 1072 1073 1074 1075 1076
/*
 * RCU torture fake writer kthread.  Repeatedly calls sync, with a random
 * delay between calls.
 */
static int
rcu_torture_fakewriter(void *arg)
{
1077
	DEFINE_TORTURE_RANDOM(rand);
1078

1079
	VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1080
	set_user_nice(current, MAX_NICE);
1081 1082

	do {
1083 1084
		schedule_timeout_uninterruptible(1 + torture_random(&rand)%10);
		udelay(torture_random(&rand) & 0x3ff);
1085
		if (cur_ops->cb_barrier != NULL &&
1086
		    torture_random(&rand) % (nfakewriters * 8) == 0) {
1087
			cur_ops->cb_barrier();
1088
		} else if (gp_normal == gp_exp) {
1089
			if (torture_random(&rand) & 0x80)
1090 1091 1092 1093
				cur_ops->sync();
			else
				cur_ops->exp_sync();
		} else if (gp_normal) {
1094
			cur_ops->sync();
1095 1096 1097
		} else {
			cur_ops->exp_sync();
		}
1098
		stutter_wait("rcu_torture_fakewriter");
1099
	} while (!torture_must_stop());
1100

1101
	torture_kthread_stopping("rcu_torture_fakewriter");
1102 1103 1104
	return 0;
}

1105 1106 1107 1108 1109 1110 1111 1112 1113
/*
 * 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;
1114
	unsigned long started;
1115
	unsigned long completed;
1116
	static DEFINE_TORTURE_RANDOM(rand);
1117 1118 1119
	static DEFINE_SPINLOCK(rand_lock);
	struct rcu_torture *p;
	int pipe_count;
1120
	unsigned long long ts;
1121 1122

	idx = cur_ops->readlock();
1123 1124 1125 1126
	if (cur_ops->started)
		started = cur_ops->started();
	else
		started = cur_ops->completed();
1127
	ts = rcu_trace_clock_local();
1128 1129 1130
	p = rcu_dereference_check(rcu_torture_current,
				  rcu_read_lock_bh_held() ||
				  rcu_read_lock_sched_held() ||
1131 1132
				  srcu_read_lock_held(srcu_ctlp) ||
				  torturing_tasks());
1133 1134 1135 1136 1137 1138 1139 1140
	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);
1141
	cur_ops->read_delay(&rand);
1142 1143 1144 1145 1146 1147 1148 1149
	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;
	}
1150
	completed = cur_ops->completed();
1151 1152
	if (pipe_count > 1) {
		do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, ts,
1153
					  started, completed);
1154
		rcu_ftrace_dump(DUMP_ALL);
1155
	}
R
Rusty Russell 已提交
1156
	__this_cpu_inc(rcu_torture_count[pipe_count]);
1157 1158 1159
	completed = completed - started;
	if (cur_ops->started)
		completed++;
1160 1161 1162 1163
	if (completed > RCU_TORTURE_PIPE_LEN) {
		/* Should not happen, but... */
		completed = RCU_TORTURE_PIPE_LEN;
	}
R
Rusty Russell 已提交
1164
	__this_cpu_inc(rcu_torture_batch[completed]);
1165 1166 1167 1168
	preempt_enable();
	cur_ops->readunlock(idx);
}

1169 1170 1171 1172 1173 1174 1175 1176 1177
/*
 * 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)
{
1178
	unsigned long started;
1179
	unsigned long completed;
1180
	int idx;
1181
	DEFINE_TORTURE_RANDOM(rand);
1182 1183
	struct rcu_torture *p;
	int pipe_count;
1184
	struct timer_list t;
1185
	unsigned long long ts;
1186

1187
	VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
1188
	set_user_nice(current, MAX_NICE);
1189
	if (irqreader && cur_ops->irq_capable)
1190
		setup_timer_on_stack(&t, rcu_torture_timer, 0);
1191

1192
	do {
1193
		if (irqreader && cur_ops->irq_capable) {
1194
			if (!timer_pending(&t))
1195
				mod_timer(&t, jiffies + 1);
1196
		}
1197
		idx = cur_ops->readlock();
1198 1199 1200 1201
		if (cur_ops->started)
			started = cur_ops->started();
		else
			started = cur_ops->completed();
1202
		ts = rcu_trace_clock_local();
1203 1204 1205
		p = rcu_dereference_check(rcu_torture_current,
					  rcu_read_lock_bh_held() ||
					  rcu_read_lock_sched_held() ||
1206 1207
					  srcu_read_lock_held(srcu_ctlp) ||
					  torturing_tasks());
1208 1209
		if (p == NULL) {
			/* Wait for rcu_torture_writer to get underway */
1210
			cur_ops->readunlock(idx);
1211 1212 1213
			schedule_timeout_interruptible(HZ);
			continue;
		}
1214 1215
		if (p->rtort_mbtest == 0)
			atomic_inc(&n_rcu_torture_mberror);
1216
		cur_ops->read_delay(&rand);
1217 1218 1219 1220 1221 1222
		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;
		}
1223
		completed = cur_ops->completed();
1224 1225
		if (pipe_count > 1) {
			do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
1226
						  ts, started, completed);
1227
			rcu_ftrace_dump(DUMP_ALL);
1228
		}
R
Rusty Russell 已提交
1229
		__this_cpu_inc(rcu_torture_count[pipe_count]);
1230 1231 1232
		completed = completed - started;
		if (cur_ops->started)
			completed++;
1233 1234 1235 1236
		if (completed > RCU_TORTURE_PIPE_LEN) {
			/* Should not happen, but... */
			completed = RCU_TORTURE_PIPE_LEN;
		}
R
Rusty Russell 已提交
1237
		__this_cpu_inc(rcu_torture_batch[completed]);
1238
		preempt_enable();
1239
		cur_ops->readunlock(idx);
1240
		stutter_wait("rcu_torture_reader");
1241
	} while (!torture_must_stop());
1242
	if (irqreader && cur_ops->irq_capable) {
1243
		del_timer_sync(&t);
1244 1245
		destroy_timer_on_stack(&t);
	}
1246
	torture_kthread_stopping("rcu_torture_reader");
1247 1248 1249 1250
	return 0;
}

/*
1251 1252 1253 1254 1255 1256
 * 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).
1257
 */
1258
static void
1259
rcu_torture_stats_print(void)
1260 1261 1262 1263 1264
{
	int cpu;
	int i;
	long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
	long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1265
	static unsigned long rtcv_snap = ULONG_MAX;
1266
	struct task_struct *wtp;
1267

1268
	for_each_possible_cpu(cpu) {
1269 1270 1271 1272 1273 1274 1275 1276 1277
		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;
	}
1278 1279 1280 1281 1282 1283 1284 1285 1286

	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));
1287
	pr_cont("rtmbe: %d rtbe: %ld rtbke: %ld rtbre: %ld ",
1288
		atomic_read(&n_rcu_torture_mberror),
1289
		n_rcu_torture_barrier_error,
1290 1291 1292 1293 1294 1295 1296
		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();
1297
	pr_cont("barrier: %ld/%ld:%ld ",
1298 1299 1300
		n_barrier_successes,
		n_barrier_attempts,
		n_rcu_torture_barrier_error);
1301
	pr_cont("cbflood: %ld\n", atomic_long_read(&n_cbfloods));
1302 1303

	pr_alert("%s%s ", torture_type, TORTURE_FLAG);
1304
	if (atomic_read(&n_rcu_torture_mberror) != 0 ||
1305
	    n_rcu_torture_barrier_error != 0 ||
1306 1307
	    n_rcu_torture_boost_ktrerror != 0 ||
	    n_rcu_torture_boost_rterror != 0 ||
1308 1309
	    n_rcu_torture_boost_failure != 0 ||
	    i > 1) {
1310
		pr_cont("%s", "!!! ");
1311
		atomic_inc(&n_rcu_torture_error);
1312
		WARN_ON_ONCE(1);
1313
	}
1314
	pr_cont("Reader Pipe: ");
1315
	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1316 1317 1318 1319 1320
		pr_cont(" %ld", pipesummary[i]);
	pr_cont("\n");

	pr_alert("%s%s ", torture_type, TORTURE_FLAG);
	pr_cont("Reader Batch: ");
1321
	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1322 1323 1324 1325 1326
		pr_cont(" %ld", batchsummary[i]);
	pr_cont("\n");

	pr_alert("%s%s ", torture_type, TORTURE_FLAG);
	pr_cont("Free-Block Circulation: ");
1327
	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1328
		pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
1329
	}
1330 1331
	pr_cont("\n");

1332
	if (cur_ops->stats)
1333
		cur_ops->stats();
1334 1335 1336 1337 1338 1339 1340 1341
	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);
1342 1343
		wtp = READ_ONCE(writer_task);
		pr_alert("??? Writer stall state %s(%d) g%lu c%lu f%#x ->state %#lx\n",
1344
			 rcu_torture_writer_state_getname(),
1345
			 rcu_torture_writer_state,
1346 1347
			 gpnum, completed, flags,
			 wtp == NULL ? ~0UL : wtp->state);
1348
		show_rcu_gp_kthreads();
1349
		rcu_ftrace_dump(DUMP_ALL);
1350 1351
	}
	rtcv_snap = rcu_torture_current_version;
1352 1353 1354 1355 1356 1357 1358 1359 1360
}

/*
 * Periodically prints torture statistics, if periodic statistics printing
 * was specified via the stat_interval module parameter.
 */
static int
rcu_torture_stats(void *arg)
{
1361
	VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
1362 1363 1364
	do {
		schedule_timeout_interruptible(stat_interval * HZ);
		rcu_torture_stats_print();
1365
		torture_shutdown_absorb("rcu_torture_stats");
1366
	} while (!torture_must_stop());
1367
	torture_kthread_stopping("rcu_torture_stats");
1368 1369 1370
	return 0;
}

1371
static inline void
1372
rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1373
{
1374 1375 1376 1377 1378 1379 1380
	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 "
1381 1382
		 "stall_cpu=%d stall_cpu_holdoff=%d "
		 "n_barrier_cbs=%d "
1383 1384 1385 1386 1387 1388
		 "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,
1389 1390
		 stall_cpu, stall_cpu_holdoff,
		 n_barrier_cbs,
1391
		 onoff_interval, onoff_holdoff);
1392 1393
}

1394
static int rcutorture_booster_cleanup(unsigned int cpu)
1395 1396 1397 1398
{
	struct task_struct *t;

	if (boost_tasks[cpu] == NULL)
1399
		return 0;
1400 1401 1402 1403 1404 1405
	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! */
1406
	torture_stop_kthread(rcu_torture_boost, t);
1407
	return 0;
1408 1409
}

1410
static int rcutorture_booster_init(unsigned int cpu)
1411 1412 1413 1414 1415 1416 1417 1418
{
	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);
1419
	VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
E
Eric Dumazet 已提交
1420 1421 1422
	boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
						  cpu_to_node(cpu),
						  "rcu_torture_boost");
1423 1424
	if (IS_ERR(boost_tasks[cpu])) {
		retval = PTR_ERR(boost_tasks[cpu]);
1425
		VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436
		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;
}

1437 1438 1439 1440
/*
 * CPU-stall kthread.  It waits as specified by stall_cpu_holdoff, then
 * induces a CPU stall for the time specified by stall_cpu.
 */
1441
static int rcu_torture_stall(void *args)
1442 1443 1444
{
	unsigned long stop_at;

1445
	VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
1446
	if (stall_cpu_holdoff > 0) {
1447
		VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
1448
		schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
1449
		VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
1450 1451 1452 1453
	}
	if (!kthread_should_stop()) {
		stop_at = get_seconds() + stall_cpu;
		/* RCU CPU stall is expected behavior in following code. */
1454
		pr_alert("rcu_torture_stall start.\n");
1455 1456 1457 1458 1459 1460
		rcu_read_lock();
		preempt_disable();
		while (ULONG_CMP_LT(get_seconds(), stop_at))
			continue;  /* Induce RCU CPU stall warning. */
		preempt_enable();
		rcu_read_unlock();
1461
		pr_alert("rcu_torture_stall end.\n");
1462
	}
1463
	torture_shutdown_absorb("rcu_torture_stall");
1464 1465 1466 1467 1468 1469 1470 1471 1472 1473
	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;
1474
	return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
1475 1476
}

1477
/* Callback function for RCU barrier testing. */
1478
static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
1479 1480 1481 1482 1483 1484 1485 1486
{
	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;
1487
	bool lastphase = 0;
1488
	bool newphase;
1489 1490 1491
	struct rcu_head rcu;

	init_rcu_head_on_stack(&rcu);
1492
	VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
1493
	set_user_nice(current, MAX_NICE);
1494 1495
	do {
		wait_event(barrier_cbs_wq[myid],
1496
			   (newphase =
1497
			    smp_load_acquire(&barrier_phase)) != lastphase ||
1498
			   torture_must_stop());
1499
		lastphase = newphase;
1500
		if (torture_must_stop())
1501
			break;
1502 1503
		/*
		 * The above smp_load_acquire() ensures barrier_phase load
P
Paul E. McKenney 已提交
1504
		 * is ordered before the following ->call().
1505
		 */
1506
		local_irq_disable(); /* Just to test no-irq call_rcu(). */
1507
		cur_ops->call(&rcu, rcu_torture_barrier_cbf);
1508
		local_irq_enable();
1509 1510
		if (atomic_dec_and_test(&barrier_cbs_count))
			wake_up(&barrier_wq);
1511
	} while (!torture_must_stop());
1512 1513
	if (cur_ops->cb_barrier != NULL)
		cur_ops->cb_barrier();
1514
	destroy_rcu_head_on_stack(&rcu);
1515
	torture_kthread_stopping("rcu_torture_barrier_cbs");
1516 1517 1518 1519 1520 1521 1522 1523
	return 0;
}

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

1524
	VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
1525 1526 1527
	do {
		atomic_set(&barrier_cbs_invoked, 0);
		atomic_set(&barrier_cbs_count, n_barrier_cbs);
1528 1529
		/* Ensure barrier_phase ordered after prior assignments. */
		smp_store_release(&barrier_phase, !barrier_phase);
1530 1531 1532 1533
		for (i = 0; i < n_barrier_cbs; i++)
			wake_up(&barrier_cbs_wq[i]);
		wait_event(barrier_wq,
			   atomic_read(&barrier_cbs_count) == 0 ||
1534 1535
			   torture_must_stop());
		if (torture_must_stop())
1536 1537
			break;
		n_barrier_attempts++;
1538
		cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
1539 1540
		if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
			n_rcu_torture_barrier_error++;
1541 1542 1543
			pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
			       atomic_read(&barrier_cbs_invoked),
			       n_barrier_cbs);
1544 1545 1546 1547
			WARN_ON_ONCE(1);
		}
		n_barrier_successes++;
		schedule_timeout_interruptible(HZ / 10);
1548
	} while (!torture_must_stop());
1549
	torture_kthread_stopping("rcu_torture_barrier");
1550 1551 1552 1553 1554 1555 1556 1557 1558
	return 0;
}

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

1559
	if (n_barrier_cbs <= 0)
1560 1561
		return 0;
	if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
1562 1563 1564 1565 1566 1567
		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);
1568 1569 1570 1571 1572 1573 1574 1575 1576 1577
		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);
1578
	if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
1579 1580 1581
		return -ENOMEM;
	for (i = 0; i < n_barrier_cbs; i++) {
		init_waitqueue_head(&barrier_cbs_wq[i]);
1582 1583 1584 1585
		ret = torture_create_kthread(rcu_torture_barrier_cbs,
					     (void *)(long)i,
					     barrier_cbs_tasks[i]);
		if (ret)
1586 1587
			return ret;
	}
1588
	return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
1589 1590 1591 1592 1593 1594 1595
}

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

1596
	torture_stop_kthread(rcu_torture_barrier, barrier_task);
1597
	if (barrier_cbs_tasks != NULL) {
1598 1599 1600
		for (i = 0; i < n_barrier_cbs; i++)
			torture_stop_kthread(rcu_torture_barrier_cbs,
					     barrier_cbs_tasks[i]);
1601 1602 1603 1604 1605 1606 1607 1608 1609
		kfree(barrier_cbs_tasks);
		barrier_cbs_tasks = NULL;
	}
	if (barrier_cbs_wq != NULL) {
		kfree(barrier_cbs_wq);
		barrier_cbs_wq = NULL;
	}
}

1610
static enum cpuhp_state rcutor_hp;
1611

1612 1613 1614 1615 1616
static void
rcu_torture_cleanup(void)
{
	int i;

1617
	rcutorture_record_test_transition();
1618
	if (torture_cleanup_begin()) {
1619 1620 1621 1622
		if (cur_ops->cb_barrier != NULL)
			cur_ops->cb_barrier();
		return;
	}
1623

1624
	rcu_torture_barrier_cleanup();
1625 1626
	torture_stop_kthread(rcu_torture_stall, stall_task);
	torture_stop_kthread(rcu_torture_writer, writer_task);
1627

1628
	if (reader_tasks) {
1629 1630 1631
		for (i = 0; i < nrealreaders; i++)
			torture_stop_kthread(rcu_torture_reader,
					     reader_tasks[i]);
1632 1633 1634 1635
		kfree(reader_tasks);
	}
	rcu_torture_current = NULL;

1636
	if (fakewriter_tasks) {
1637
		for (i = 0; i < nfakewriters; i++) {
1638 1639
			torture_stop_kthread(rcu_torture_fakewriter,
					     fakewriter_tasks[i]);
1640 1641 1642 1643 1644
		}
		kfree(fakewriter_tasks);
		fakewriter_tasks = NULL;
	}

1645 1646
	torture_stop_kthread(rcu_torture_stats, stats_task);
	torture_stop_kthread(rcu_torture_fqs, fqs_task);
1647 1648
	for (i = 0; i < ncbflooders; i++)
		torture_stop_kthread(rcu_torture_cbflood, cbflood_task[i]);
1649
	if ((test_boost == 1 && cur_ops->can_boost) ||
1650 1651
	    test_boost == 2)
		cpuhp_remove_state(rcutor_hp);
1652

1653 1654 1655 1656
	/*
	 * Wait for all RCU callbacks to fire, then do flavor-specific
	 * cleanup operations.
	 */
1657 1658
	if (cur_ops->cb_barrier != NULL)
		cur_ops->cb_barrier();
1659 1660
	if (cur_ops->cleanup != NULL)
		cur_ops->cleanup();
1661 1662

	rcu_torture_stats_print();  /* -After- the stats thread is stopped! */
1663

1664
	if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
1665
		rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
1666
	else if (torture_onoff_failures())
1667 1668
		rcu_torture_print_module_parms(cur_ops,
					       "End of test: RCU_HOTPLUG");
1669
	else
1670
		rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
1671
	torture_cleanup_end();
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 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729
#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 */
}

1730
static int __init
1731 1732 1733 1734 1735
rcu_torture_init(void)
{
	int i;
	int cpu;
	int firsterr = 0;
1736
	static struct rcu_torture_ops *torture_ops[] = {
1737 1738
		&rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops,
		&sched_ops, RCUTORTURE_TASKS_OPS
1739
	};
1740

1741
	if (!torture_init_begin(torture_type, verbose, &torture_runnable))
1742
		return -EBUSY;
1743

1744
	/* Process args and tell the world that the torturer is on the job. */
1745
	for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1746
		cur_ops = torture_ops[i];
1747
		if (strcmp(torture_type, cur_ops->name) == 0)
1748 1749
			break;
	}
1750
	if (i == ARRAY_SIZE(torture_ops)) {
1751 1752 1753
		pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
			 torture_type);
		pr_alert("rcu-torture types:");
1754
		for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1755 1756
			pr_alert(" %s", torture_ops[i]->name);
		pr_alert("\n");
1757 1758
		firsterr = -EINVAL;
		goto unwind;
1759
	}
1760
	if (cur_ops->fqs == NULL && fqs_duration != 0) {
1761
		pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
1762 1763
		fqs_duration = 0;
	}
1764
	if (cur_ops->init)
1765
		cur_ops->init();
1766

1767
	if (nreaders >= 0) {
1768
		nrealreaders = nreaders;
1769
	} else {
1770
		nrealreaders = num_online_cpus() - 2 - nreaders;
1771 1772 1773
		if (nrealreaders <= 0)
			nrealreaders = 1;
	}
1774
	rcu_torture_print_module_parms(cur_ops, "Start of test");
1775 1776 1777 1778

	/* Set up the freelist. */

	INIT_LIST_HEAD(&rcu_torture_freelist);
1779
	for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1780
		rcu_tortures[i].rtort_mbtest = 0;
1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791
		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);
1792 1793
	atomic_set(&n_rcu_torture_mberror, 0);
	atomic_set(&n_rcu_torture_error, 0);
1794
	n_rcu_torture_barrier_error = 0;
1795 1796 1797 1798
	n_rcu_torture_boost_ktrerror = 0;
	n_rcu_torture_boost_rterror = 0;
	n_rcu_torture_boost_failure = 0;
	n_rcu_torture_boosts = 0;
1799 1800
	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
		atomic_set(&rcu_torture_wcount[i], 0);
1801
	for_each_possible_cpu(cpu) {
1802 1803 1804 1805 1806 1807 1808 1809
		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. */

1810 1811 1812
	firsterr = torture_create_kthread(rcu_torture_writer, NULL,
					  writer_task);
	if (firsterr)
1813
		goto unwind;
1814 1815 1816 1817 1818 1819 1820 1821 1822
	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;
		}
1823 1824
	}
	for (i = 0; i < nfakewriters; i++) {
1825 1826 1827
		firsterr = torture_create_kthread(rcu_torture_fakewriter,
						  NULL, fakewriter_tasks[i]);
		if (firsterr)
1828 1829
			goto unwind;
	}
1830
	reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
1831 1832
			       GFP_KERNEL);
	if (reader_tasks == NULL) {
1833
		VERBOSE_TOROUT_ERRSTRING("out of memory");
1834 1835 1836 1837
		firsterr = -ENOMEM;
		goto unwind;
	}
	for (i = 0; i < nrealreaders; i++) {
1838 1839 1840
		firsterr = torture_create_kthread(rcu_torture_reader, NULL,
						  reader_tasks[i]);
		if (firsterr)
1841 1842 1843
			goto unwind;
	}
	if (stat_interval > 0) {
1844 1845 1846
		firsterr = torture_create_kthread(rcu_torture_stats, NULL,
						  stats_task);
		if (firsterr)
1847 1848
			goto unwind;
	}
1849
	if (test_no_idle_hz && shuffle_interval > 0) {
1850 1851
		firsterr = torture_shuffle_init(shuffle_interval * HZ);
		if (firsterr)
1852 1853
			goto unwind;
	}
1854 1855 1856
	if (stutter < 0)
		stutter = 0;
	if (stutter) {
1857 1858
		firsterr = torture_stutter_init(stutter * HZ);
		if (firsterr)
1859 1860
			goto unwind;
	}
1861 1862 1863
	if (fqs_duration < 0)
		fqs_duration = 0;
	if (fqs_duration) {
1864
		/* Create the fqs thread */
1865 1866
		firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
						  fqs_task);
1867
		if (firsterr)
1868 1869
			goto unwind;
	}
1870 1871 1872 1873 1874 1875 1876 1877
	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;
1878 1879 1880 1881 1882 1883 1884

		firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE",
					     rcutorture_booster_init,
					     rcutorture_booster_cleanup);
		if (firsterr < 0)
			goto unwind;
		rcutor_hp = firsterr;
1885
	}
1886 1887
	firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
	if (firsterr)
1888
		goto unwind;
1889 1890
	firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval * HZ);
	if (firsterr)
1891
		goto unwind;
1892 1893
	firsterr = rcu_torture_stall_init();
	if (firsterr)
1894
		goto unwind;
1895 1896
	firsterr = rcu_torture_barrier_init();
	if (firsterr)
1897
		goto unwind;
1898 1899
	if (object_debug)
		rcu_test_debug_objects();
1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917
	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;
		}
	}
1918
	rcutorture_record_test_transition();
1919
	torture_init_end();
1920 1921 1922
	return 0;

unwind:
1923
	torture_init_end();
1924 1925 1926 1927 1928 1929
	rcu_torture_cleanup();
	return firsterr;
}

module_init(rcu_torture_init);
module_exit(rcu_torture_cleanup);