Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull RCU updates from Ingo Molnar:
 "Main changes:

   - Torture-test changes, including refactoring of rcutorture and
     introduction of a vestigial locktorture.

   - Real-time latency fixes.

   - Documentation updates.

   - Miscellaneous fixes"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (77 commits)
  rcu: Provide grace-period piggybacking API
  rcu: Ensure kernel/rcu/rcu.h can be sourced/used stand-alone
  rcu: Fix sparse warning for rcu_expedited from kernel/ksysfs.c
  notifier: Substitute rcu_access_pointer() for rcu_dereference_raw()
  Documentation/memory-barriers.txt: Clarify release/acquire ordering
  rcutorture: Save kvm.sh output to log
  rcutorture: Add a lock_busted to test the test
  rcutorture: Place kvm-test-1-run.sh output into res directory
  rcutorture: Rename TREE_RCU-Kconfig.txt
  locktorture: Add kvm-recheck.sh plug-in for locktorture
  rcutorture: Gracefully handle NULL cleanup hooks
  locktorture: Add vestigial locktorture configuration
  rcutorture: Introduce "rcu" directory level underneath configs
  rcutorture: Rename kvm-test-1-rcu.sh
  rcutorture: Remove RCU dependencies from ver_functions.sh API
  rcutorture: Create CFcommon file for common Kconfig parameters
  rcutorture: Create config files for scripted test-the-test testing
  rcutorture: Add an rcu_busted to test the test
  locktorture: Add a lock-torture kernel module
  rcutorture: Abstract kvm-recheck.sh
  ...

17 files changed, 1491 insertions, 828 deletions

diff --git a/kernel/Makefile b/kernel/Makefile
index bc010ee272b6..5c0e7666811d 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -93,6 +93,7 @@ obj-$(CONFIG_PADATA) += padata.o
 obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
 obj-$(CONFIG_JUMP_LABEL) += jump_label.o
 obj-$(CONFIG_CONTEXT_TRACKING) += context_tracking.o
+obj-$(CONFIG_TORTURE_TEST) += torture.o
 
 $(obj)/configs.o: $(obj)/config_data.h
 
diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c
index d945a949760f..e660964086e2 100644
--- a/kernel/ksysfs.c
+++ b/kernel/ksysfs.c
@@ -19,6 +19,8 @@
 #include <linux/sched.h>
 #include <linux/capability.h>
 
+#include <linux/rcupdate.h>	/* rcu_expedited */
+
 #define KERNEL_ATTR_RO(_name) \
 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
 
diff --git a/kernel/locking/Makefile b/kernel/locking/Makefile
index 2a9ee96ecf00..306a76b51e0f 100644
--- a/kernel/locking/Makefile
+++ b/kernel/locking/Makefile
@@ -23,3 +23,4 @@ obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
 obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
 obj-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem-xadd.o
 obj-$(CONFIG_PERCPU_RWSEM) += percpu-rwsem.o
+obj-$(CONFIG_LOCK_TORTURE_TEST) += locktorture.o
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
new file mode 100644
index 000000000000..f26b1a18e34e
--- /dev/null
+++ b/kernel/locking/locktorture.c
@@ -0,0 +1,452 @@
+/*
+ * Module-based torture test facility for locking
+ *
+ * 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
+ * along with this program; if not, you can access it online at
+ * http://www.gnu.org/licenses/gpl-2.0.html.
+ *
+ * Copyright (C) IBM Corporation, 2014
+ *
+ * Author: Paul E. McKenney <paulmck@us.ibm.com>
+ *	Based on kernel/rcu/torture.c.
+ */
+#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/interrupt.h>
+#include <linux/sched.h>
+#include <linux/atomic.h>
+#include <linux/bitops.h>
+#include <linux/completion.h>
+#include <linux/moduleparam.h>
+#include <linux/percpu.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/freezer.h>
+#include <linux/cpu.h>
+#include <linux/delay.h>
+#include <linux/stat.h>
+#include <linux/slab.h>
+#include <linux/trace_clock.h>
+#include <asm/byteorder.h>
+#include <linux/torture.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
+
+torture_param(int, nwriters_stress, -1,
+	     "Number of write-locking stress-test threads");
+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 jiffies between shuffles, 0=disable");
+torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable.");
+torture_param(int, stat_interval, 60,
+	     "Number of seconds between stats printk()s");
+torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
+torture_param(bool, verbose, true,
+	     "Enable verbose debugging printk()s");
+
+static char *torture_type = "spin_lock";
+module_param(torture_type, charp, 0444);
+MODULE_PARM_DESC(torture_type,
+		 "Type of lock to torture (spin_lock, spin_lock_irq, ...)");
+
+static atomic_t n_lock_torture_errors;
+
+static struct task_struct *stats_task;
+static struct task_struct **writer_tasks;
+
+static int nrealwriters_stress;
+static bool lock_is_write_held;
+
+struct lock_writer_stress_stats {
+	long n_write_lock_fail;
+	long n_write_lock_acquired;
+};
+static struct lock_writer_stress_stats *lwsa;
+
+#if defined(MODULE) || defined(CONFIG_LOCK_TORTURE_TEST_RUNNABLE)
+#define LOCKTORTURE_RUNNABLE_INIT 1
+#else
+#define LOCKTORTURE_RUNNABLE_INIT 0
+#endif
+int locktorture_runnable = LOCKTORTURE_RUNNABLE_INIT;
+module_param(locktorture_runnable, int, 0444);
+MODULE_PARM_DESC(locktorture_runnable, "Start locktorture at boot");
+
+/* Forward reference. */
+static void lock_torture_cleanup(void);
+
+/*
+ * Operations vector for selecting different types of tests.
+ */
+struct lock_torture_ops {
+	void (*init)(void);
+	int (*writelock)(void);
+	void (*write_delay)(struct torture_random_state *trsp);
+	void (*writeunlock)(void);
+	unsigned long flags;
+	const char *name;
+};
+
+static struct lock_torture_ops *cur_ops;
+
+/*
+ * Definitions for lock torture testing.
+ */
+
+static int torture_lock_busted_write_lock(void)
+{
+	return 0;  /* BUGGY, do not use in real life!!! */
+}
+
+static void torture_lock_busted_write_delay(struct torture_random_state *trsp)
+{
+	const unsigned long longdelay_us = 100;
+
+	/* We want a long delay occasionally to force massive contention.  */
+	if (!(torture_random(trsp) %
+	      (nrealwriters_stress * 2000 * longdelay_us)))
+		mdelay(longdelay_us);
+#ifdef CONFIG_PREEMPT
+	if (!(torture_random(trsp) % (nrealwriters_stress * 20000)))
+		preempt_schedule();  /* Allow test to be preempted. */
+#endif
+}
+
+static void torture_lock_busted_write_unlock(void)
+{
+	  /* BUGGY, do not use in real life!!! */
+}
+
+static struct lock_torture_ops lock_busted_ops = {
+	.writelock	= torture_lock_busted_write_lock,
+	.write_delay	= torture_lock_busted_write_delay,
+	.writeunlock	= torture_lock_busted_write_unlock,
+	.name		= "lock_busted"
+};
+
+static DEFINE_SPINLOCK(torture_spinlock);
+
+static int torture_spin_lock_write_lock(void) __acquires(torture_spinlock)
+{
+	spin_lock(&torture_spinlock);
+	return 0;
+}
+
+static void torture_spin_lock_write_delay(struct torture_random_state *trsp)
+{
+	const unsigned long shortdelay_us = 2;
+	const unsigned long longdelay_us = 100;
+
+	/* We want a short delay mostly to emulate likely code, and
+	 * we want a long delay occasionally to force massive contention.
+	 */
+	if (!(torture_random(trsp) %
+	      (nrealwriters_stress * 2000 * longdelay_us)))
+		mdelay(longdelay_us);
+	if (!(torture_random(trsp) %
+	      (nrealwriters_stress * 2 * shortdelay_us)))
+		udelay(shortdelay_us);
+#ifdef CONFIG_PREEMPT
+	if (!(torture_random(trsp) % (nrealwriters_stress * 20000)))
+		preempt_schedule();  /* Allow test to be preempted. */
+#endif
+}
+
+static void torture_spin_lock_write_unlock(void) __releases(torture_spinlock)
+{
+	spin_unlock(&torture_spinlock);
+}
+
+static struct lock_torture_ops spin_lock_ops = {
+	.writelock	= torture_spin_lock_write_lock,
+	.write_delay	= torture_spin_lock_write_delay,
+	.writeunlock	= torture_spin_lock_write_unlock,
+	.name		= "spin_lock"
+};
+
+static int torture_spin_lock_write_lock_irq(void)
+__acquires(torture_spinlock_irq)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&torture_spinlock, flags);
+	cur_ops->flags = flags;
+	return 0;
+}
+
+static void torture_lock_spin_write_unlock_irq(void)
+__releases(torture_spinlock)
+{
+	spin_unlock_irqrestore(&torture_spinlock, cur_ops->flags);
+}
+
+static struct lock_torture_ops spin_lock_irq_ops = {
+	.writelock	= torture_spin_lock_write_lock_irq,
+	.write_delay	= torture_spin_lock_write_delay,
+	.writeunlock	= torture_lock_spin_write_unlock_irq,
+	.name		= "spin_lock_irq"
+};
+
+/*
+ * Lock torture writer kthread.  Repeatedly acquires and releases
+ * the lock, checking for duplicate acquisitions.
+ */
+static int lock_torture_writer(void *arg)
+{
+	struct lock_writer_stress_stats *lwsp = arg;
+	static DEFINE_TORTURE_RANDOM(rand);
+
+	VERBOSE_TOROUT_STRING("lock_torture_writer task started");
+	set_user_nice(current, 19);
+
+	do {
+		schedule_timeout_uninterruptible(1);
+		cur_ops->writelock();
+		if (WARN_ON_ONCE(lock_is_write_held))
+			lwsp->n_write_lock_fail++;
+		lock_is_write_held = 1;
+		lwsp->n_write_lock_acquired++;
+		cur_ops->write_delay(&rand);
+		lock_is_write_held = 0;
+		cur_ops->writeunlock();
+		stutter_wait("lock_torture_writer");
+	} while (!torture_must_stop());
+	torture_kthread_stopping("lock_torture_writer");
+	return 0;
+}
+
+/*
+ * Create an lock-torture-statistics message in the specified buffer.
+ */
+static void lock_torture_printk(char *page)
+{
+	bool fail = 0;
+	int i;
+	long max = 0;
+	long min = lwsa[0].n_write_lock_acquired;
+	long long sum = 0;
+
+	for (i = 0; i < nrealwriters_stress; i++) {
+		if (lwsa[i].n_write_lock_fail)
+			fail = true;
+		sum += lwsa[i].n_write_lock_acquired;
+		if (max < lwsa[i].n_write_lock_fail)
+			max = lwsa[i].n_write_lock_fail;
+		if (min > lwsa[i].n_write_lock_fail)
+			min = lwsa[i].n_write_lock_fail;
+	}
+	page += sprintf(page, "%s%s ", torture_type, TORTURE_FLAG);
+	page += sprintf(page,
+			"Writes:  Total: %lld  Max/Min: %ld/%ld %s  Fail: %d %s\n",
+			sum, max, min, max / 2 > min ? "???" : "",
+			fail, fail ? "!!!" : "");
+	if (fail)
+		atomic_inc(&n_lock_torture_errors);
+}
+
+/*
+ * 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 lock_torture_stats kthread full control
+ * (or the init/cleanup functions when lock_torture_stats thread is not
+ * running).
+ */
+static void lock_torture_stats_print(void)
+{
+	int size = nrealwriters_stress * 200 + 8192;
+	char *buf;
+
+	buf = kmalloc(size, GFP_KERNEL);
+	if (!buf) {
+		pr_err("lock_torture_stats_print: Out of memory, need: %d",
+		       size);
+		return;
+	}
+	lock_torture_printk(buf);
+	pr_alert("%s", buf);
+	kfree(buf);
+}
+
+/*
+ * Periodically prints torture statistics, if periodic statistics printing
+ * was specified via the stat_interval module parameter.
+ *
+ * No need to worry about fullstop here, since this one doesn't reference
+ * volatile state or register callbacks.
+ */
+static int lock_torture_stats(void *arg)
+{
+	VERBOSE_TOROUT_STRING("lock_torture_stats task started");
+	do {
+		schedule_timeout_interruptible(stat_interval * HZ);
+		lock_torture_stats_print();
+		torture_shutdown_absorb("lock_torture_stats");
+	} while (!torture_must_stop());
+	torture_kthread_stopping("lock_torture_stats");
+	return 0;
+}
+
+static inline void
+lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
+				const char *tag)
+{
+	pr_alert("%s" TORTURE_FLAG
+		 "--- %s: nwriters_stress=%d stat_interval=%d verbose=%d shuffle_interval=%d stutter=%d shutdown_secs=%d onoff_interval=%d onoff_holdoff=%d\n",
+		 torture_type, tag, nrealwriters_stress, stat_interval, verbose,
+		 shuffle_interval, stutter, shutdown_secs,
+		 onoff_interval, onoff_holdoff);
+}
+
+static void lock_torture_cleanup(void)
+{
+	int i;
+
+	if (torture_cleanup())
+		return;
+
+	if (writer_tasks) {
+		for (i = 0; i < nrealwriters_stress; i++)
+			torture_stop_kthread(lock_torture_writer,
+					     writer_tasks[i]);
+		kfree(writer_tasks);
+		writer_tasks = NULL;
+	}
+
+	torture_stop_kthread(lock_torture_stats, stats_task);
+	lock_torture_stats_print();  /* -After- the stats thread is stopped! */
+
+	if (atomic_read(&n_lock_torture_errors))
+		lock_torture_print_module_parms(cur_ops,
+						"End of test: FAILURE");
+	else if (torture_onoff_failures())
+		lock_torture_print_module_parms(cur_ops,
+						"End of test: LOCK_HOTPLUG");
+	else
+		lock_torture_print_module_parms(cur_ops,
+						"End of test: SUCCESS");
+}
+
+static int __init lock_torture_init(void)
+{
+	int i;
+	int firsterr = 0;
+	static struct lock_torture_ops *torture_ops[] = {
+		&lock_busted_ops, &spin_lock_ops, &spin_lock_irq_ops,
+	};
+
+	torture_init_begin(torture_type, verbose, &locktorture_runnable);
+
+	/* Process args and tell the world that the torturer is on the job. */
+	for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
+		cur_ops = torture_ops[i];
+		if (strcmp(torture_type, cur_ops->name) == 0)
+			break;
+	}
+	if (i == ARRAY_SIZE(torture_ops)) {
+		pr_alert("lock-torture: invalid torture type: \"%s\"\n",
+			 torture_type);
+		pr_alert("lock-torture types:");
+		for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
+			pr_alert(" %s", torture_ops[i]->name);
+		pr_alert("\n");
+		torture_init_end();
+		return -EINVAL;
+	}
+	if (cur_ops->init)
+		cur_ops->init(); /* no "goto unwind" prior to this point!!! */
+
+	if (nwriters_stress >= 0)
+		nrealwriters_stress = nwriters_stress;
+	else
+		nrealwriters_stress = 2 * num_online_cpus();
+	lock_torture_print_module_parms(cur_ops, "Start of test");
+
+	/* Initialize the statistics so that each run gets its own numbers. */
+
+	lock_is_write_held = 0;
+	lwsa = kmalloc(sizeof(*lwsa) * nrealwriters_stress, GFP_KERNEL);
+	if (lwsa == NULL) {
+		VERBOSE_TOROUT_STRING("lwsa: Out of memory");
+		firsterr = -ENOMEM;
+		goto unwind;
+	}
+	for (i = 0; i < nrealwriters_stress; i++) {
+		lwsa[i].n_write_lock_fail = 0;
+		lwsa[i].n_write_lock_acquired = 0;
+	}
+
+	/* Start up the kthreads. */
+
+	if (onoff_interval > 0) {
+		firsterr = torture_onoff_init(onoff_holdoff * HZ,
+					      onoff_interval * HZ);
+		if (firsterr)
+			goto unwind;
+	}
+	if (shuffle_interval > 0) {
+		firsterr = torture_shuffle_init(shuffle_interval);
+		if (firsterr)
+			goto unwind;
+	}
+	if (shutdown_secs > 0) {
+		firsterr = torture_shutdown_init(shutdown_secs,
+						 lock_torture_cleanup);
+		if (firsterr)
+			goto unwind;
+	}
+	if (stutter > 0) {
+		firsterr = torture_stutter_init(stutter);
+		if (firsterr)
+			goto unwind;
+	}
+
+	writer_tasks = kzalloc(nrealwriters_stress * sizeof(writer_tasks[0]),
+			       GFP_KERNEL);
+	if (writer_tasks == NULL) {
+		VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory");
+		firsterr = -ENOMEM;
+		goto unwind;
+	}
+	for (i = 0; i < nrealwriters_stress; i++) {
+		firsterr = torture_create_kthread(lock_torture_writer, &lwsa[i],
+						  writer_tasks[i]);
+		if (firsterr)
+			goto unwind;
+	}
+	if (stat_interval > 0) {
+		firsterr = torture_create_kthread(lock_torture_stats, NULL,
+						  stats_task);
+		if (firsterr)
+			goto unwind;
+	}
+	torture_init_end();
+	return 0;
+
+unwind:
+	torture_init_end();
+	lock_torture_cleanup();
+	return firsterr;
+}
+
+module_init(lock_torture_init);
+module_exit(lock_torture_cleanup);
diff --git a/kernel/notifier.c b/kernel/notifier.c
index 2d5cc4ccff7f..db4c8b08a50c 100644
--- a/kernel/notifier.c
+++ b/kernel/notifier.c
@@ -309,7 +309,7 @@ int __blocking_notifier_call_chain(struct blocking_notifier_head *nh,
 	 * racy then it does not matter what the result of the test
 	 * is, we re-check the list after having taken the lock anyway:
 	 */
-	if (rcu_dereference_raw(nh->head)) {
+	if (rcu_access_pointer(nh->head)) {
 		down_read(&nh->rwsem);
 		ret = notifier_call_chain(&nh->head, val, v, nr_to_call,
 					nr_calls);
diff --git a/kernel/rcu/Makefile b/kernel/rcu/Makefile
index 01e9ec37a3e3..807ccfbf69b3 100644
--- a/kernel/rcu/Makefile
+++ b/kernel/rcu/Makefile
@@ -1,5 +1,5 @@
 obj-y += update.o srcu.o
-obj-$(CONFIG_RCU_TORTURE_TEST) += torture.o
+obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o
 obj-$(CONFIG_TREE_RCU) += tree.o
 obj-$(CONFIG_TREE_PREEMPT_RCU) += tree.o
 obj-$(CONFIG_TREE_RCU_TRACE) += tree_trace.o
diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index 79c3877e9c5b..bfda2726ca45 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -12,8 +12,8 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ * along with this program; if not, you can access it online at
+ * http://www.gnu.org/licenses/gpl-2.0.html.
  *
  * Copyright IBM Corporation, 2011
  *
@@ -23,6 +23,7 @@
 #ifndef __LINUX_RCU_H
 #define __LINUX_RCU_H
 
+#include <trace/events/rcu.h>
 #ifdef CONFIG_RCU_TRACE
 #define RCU_TRACE(stmt) stmt
 #else /* #ifdef CONFIG_RCU_TRACE */
@@ -116,8 +117,6 @@ static inline bool __rcu_reclaim(const char *rn, struct rcu_head *head)
 	}
 }
 
-extern int rcu_expedited;
-
 #ifdef CONFIG_RCU_STALL_COMMON
 
 extern int rcu_cpu_stall_suppress;
diff --git a/kernel/rcu/torture.c b/kernel/rcu/rcutorture.c
index 732f8ae3086a..f59d48597dde 100644
--- a/kernel/rcu/torture.c
+++ b/kernel/rcu/rcutorture.c
@@ -12,8 +12,8 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ * along with this program; if not, you can access it online at
+ * http://www.gnu.org/licenses/gpl-2.0.html.
  *
  * Copyright (C) IBM Corporation, 2005, 2006
  *
@@ -48,110 +48,58 @@
 #include <linux/slab.h>
 #include <linux/trace_clock.h>
 #include <asm/byteorder.h>
+#include <linux/torture.h>
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@freedesktop.org>");
 
-MODULE_ALIAS("rcutorture");
-#ifdef MODULE_PARAM_PREFIX
-#undef MODULE_PARAM_PREFIX
-#endif
-#define MODULE_PARAM_PREFIX "rcutorture."
-
-static int fqs_duration;
-module_param(fqs_duration, int, 0444);
-MODULE_PARM_DESC(fqs_duration, "Duration of fqs bursts (us), 0 to disable");
-static int fqs_holdoff;
-module_param(fqs_holdoff, int, 0444);
-MODULE_PARM_DESC(fqs_holdoff, "Holdoff time within fqs bursts (us)");
-static int fqs_stutter = 3;
-module_param(fqs_stutter, int, 0444);
-MODULE_PARM_DESC(fqs_stutter, "Wait time between fqs bursts (s)");
-static bool gp_exp;
-module_param(gp_exp, bool, 0444);
-MODULE_PARM_DESC(gp_exp, "Use expedited GP wait primitives");
-static bool gp_normal;
-module_param(gp_normal, bool, 0444);
-MODULE_PARM_DESC(gp_normal, "Use normal (non-expedited) GP wait primitives");
-static int irqreader = 1;
-module_param(irqreader, int, 0444);
-MODULE_PARM_DESC(irqreader, "Allow RCU readers from irq handlers");
-static int n_barrier_cbs;
-module_param(n_barrier_cbs, int, 0444);
-MODULE_PARM_DESC(n_barrier_cbs, "# of callbacks/kthreads for barrier testing");
-static int nfakewriters = 4;
-module_param(nfakewriters, int, 0444);
-MODULE_PARM_DESC(nfakewriters, "Number of RCU fake writer threads");
-static int nreaders = -1;
-module_param(nreaders, int, 0444);
-MODULE_PARM_DESC(nreaders, "Number of RCU reader threads");
-static int object_debug;
-module_param(object_debug, int, 0444);
-MODULE_PARM_DESC(object_debug, "Enable debug-object double call_rcu() testing");
-static int onoff_holdoff;
-module_param(onoff_holdoff, int, 0444);
-MODULE_PARM_DESC(onoff_holdoff, "Time after boot before CPU hotplugs (s)");
-static int onoff_interval;
-module_param(onoff_interval, int, 0444);
-MODULE_PARM_DESC(onoff_interval, "Time between CPU hotplugs (s), 0=disable");
-static int shuffle_interval = 3;
-module_param(shuffle_interval, int, 0444);
-MODULE_PARM_DESC(shuffle_interval, "Number of seconds between shuffles");
-static int shutdown_secs;
-module_param(shutdown_secs, int, 0444);
-MODULE_PARM_DESC(shutdown_secs, "Shutdown time (s), <= zero to disable.");
-static int stall_cpu;
-module_param(stall_cpu, int, 0444);
-MODULE_PARM_DESC(stall_cpu, "Stall duration (s), zero to disable.");
-static int stall_cpu_holdoff = 10;
-module_param(stall_cpu_holdoff, int, 0444);
-MODULE_PARM_DESC(stall_cpu_holdoff, "Time to wait before starting stall (s).");
-static int stat_interval = 60;
-module_param(stat_interval, int, 0644);
-MODULE_PARM_DESC(stat_interval, "Number of seconds between stats printk()s");
-static int stutter = 5;
-module_param(stutter, int, 0444);
-MODULE_PARM_DESC(stutter, "Number of seconds to run/halt test");
-static int test_boost = 1;
-module_param(test_boost, int, 0444);
-MODULE_PARM_DESC(test_boost, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
-static int test_boost_duration = 4;
-module_param(test_boost_duration, int, 0444);
-MODULE_PARM_DESC(test_boost_duration, "Duration of each boost test, seconds.");
-static int test_boost_interval = 7;
-module_param(test_boost_interval, int, 0444);
-MODULE_PARM_DESC(test_boost_interval, "Interval between boost tests, seconds.");
-static bool test_no_idle_hz = true;
-module_param(test_no_idle_hz, bool, 0444);
-MODULE_PARM_DESC(test_no_idle_hz, "Test support for tickless idle CPUs");
+
+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)");
+torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
+torture_param(bool, gp_normal, false,
+	     "Use normal (non-expedited) GP wait primitives");
+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");
+torture_param(bool, verbose, true,
+	     "Enable verbose debugging printk()s");
+
 static char *torture_type = "rcu";
 module_param(torture_type, charp, 0444);
 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, ...)");
-static bool verbose;
-module_param(verbose, bool, 0444);
-MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s");
-
-#define TORTURE_FLAG "-torture:"
-#define PRINTK_STRING(s) \
-	do { pr_alert("%s" TORTURE_FLAG s "\n", torture_type); } while (0)
-#define VERBOSE_PRINTK_STRING(s) \
-	do { if (verbose) pr_alert("%s" TORTURE_FLAG s "\n", torture_type); } while (0)
-#define VERBOSE_PRINTK_ERRSTRING(s) \
-	do { if (verbose) pr_alert("%s" TORTURE_FLAG "!!! " s "\n", torture_type); } while (0)
 
 static int nrealreaders;
 static struct task_struct *writer_task;
 static struct task_struct **fakewriter_tasks;
 static struct task_struct **reader_tasks;
 static struct task_struct *stats_task;
-static struct task_struct *shuffler_task;
-static struct task_struct *stutter_task;
 static struct task_struct *fqs_task;
 static struct task_struct *boost_tasks[NR_CPUS];
-static struct task_struct *shutdown_task;
-#ifdef CONFIG_HOTPLUG_CPU
-static struct task_struct *onoff_task;
-#endif /* #ifdef CONFIG_HOTPLUG_CPU */
 static struct task_struct *stall_task;
 static struct task_struct **barrier_cbs_tasks;
 static struct task_struct *barrier_task;
@@ -170,10 +118,10 @@ static struct rcu_torture __rcu *rcu_torture_current;
 static unsigned long rcu_torture_current_version;
 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
 static DEFINE_SPINLOCK(rcu_torture_lock);
-static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) =
-	{ 0 };
-static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) =
-	{ 0 };
+static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1],
+		      rcu_torture_count) = { 0 };
+static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1],
+		      rcu_torture_batch) = { 0 };
 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
 static atomic_t n_rcu_torture_alloc;
 static atomic_t n_rcu_torture_alloc_fail;
@@ -186,22 +134,9 @@ static long n_rcu_torture_boost_rterror;
 static long n_rcu_torture_boost_failure;
 static long n_rcu_torture_boosts;
 static long n_rcu_torture_timers;
-static long n_offline_attempts;
-static long n_offline_successes;
-static unsigned long sum_offline;
-static int min_offline = -1;
-static int max_offline;
-static long n_online_attempts;
-static long n_online_successes;
-static unsigned long sum_online;
-static int min_online = -1;
-static int max_online;
 static long n_barrier_attempts;
 static long n_barrier_successes;
 static struct list_head rcu_torture_removed;
-static cpumask_var_t shuffle_tmp_mask;
-
-static int stutter_pause_test;
 
 #if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
 #define RCUTORTURE_RUNNABLE_INIT 1
@@ -232,7 +167,6 @@ static u64 notrace rcu_trace_clock_local(void)
 }
 #endif /* #else #ifdef CONFIG_RCU_TRACE */
 
-static unsigned long shutdown_time;	/* jiffies to system shutdown. */
 static unsigned long boost_starttime;	/* jiffies of next boost test start. */
 DEFINE_MUTEX(boost_mutex);		/* protect setting boost_starttime */
 					/*  and boost task create/destroy. */
@@ -242,51 +176,6 @@ 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);
 
-/* Mediate rmmod and system shutdown.  Concurrent rmmod & shutdown illegal! */
-
-#define FULLSTOP_DONTSTOP 0	/* Normal operation. */
-#define FULLSTOP_SHUTDOWN 1	/* System shutdown with rcutorture running. */
-#define FULLSTOP_RMMOD    2	/* Normal rmmod of rcutorture. */
-static int fullstop = FULLSTOP_RMMOD;
-/*
- * Protect fullstop transitions and spawning of kthreads.
- */
-static DEFINE_MUTEX(fullstop_mutex);
-
-/* Forward reference. */
-static void rcu_torture_cleanup(void);
-
-/*
- * Detect and respond to a system shutdown.
- */
-static int
-rcutorture_shutdown_notify(struct notifier_block *unused1,
-			   unsigned long unused2, void *unused3)
-{
-	mutex_lock(&fullstop_mutex);
-	if (fullstop == FULLSTOP_DONTSTOP)
-		fullstop = FULLSTOP_SHUTDOWN;
-	else
-		pr_warn(/* but going down anyway, so... */
-		       "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
-	mutex_unlock(&fullstop_mutex);
-	return NOTIFY_DONE;
-}
-
-/*
- * Absorb kthreads into a kernel function that won't return, so that
- * they won't ever access module text or data again.
- */
-static void rcutorture_shutdown_absorb(const char *title)
-{
-	if (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
-		pr_notice(
-		       "rcutorture thread %s parking due to system shutdown\n",
-		       title);
-		schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
-	}
-}
-
 /*
  * Allocate an element from the rcu_tortures pool.
  */
@@ -320,44 +209,6 @@ rcu_torture_free(struct rcu_torture *p)
 	spin_unlock_bh(&rcu_torture_lock);
 }
 
-struct rcu_random_state {
-	unsigned long rrs_state;
-	long rrs_count;
-};
-
-#define RCU_RANDOM_MULT 39916801  /* prime */
-#define RCU_RANDOM_ADD	479001701 /* prime */
-#define RCU_RANDOM_REFRESH 10000
-
-#define DEFINE_RCU_RANDOM(name) struct rcu_random_state name = { 0, 0 }
-
-/*
- * Crude but fast random-number generator.  Uses a linear congruential
- * generator, with occasional help from cpu_clock().
- */
-static unsigned long
-rcu_random(struct rcu_random_state *rrsp)
-{
-	if (--rrsp->rrs_count < 0) {
-		rrsp->rrs_state += (unsigned long)local_clock();
-		rrsp->rrs_count = RCU_RANDOM_REFRESH;
-	}
-	rrsp->rrs_state = rrsp->rrs_state * RCU_RANDOM_MULT + RCU_RANDOM_ADD;
-	return swahw32(rrsp->rrs_state);
-}
-
-static void
-rcu_stutter_wait(const char *title)
-{
-	while (stutter_pause_test || !rcutorture_runnable) {
-		if (rcutorture_runnable)
-			schedule_timeout_interruptible(1);
-		else
-			schedule_timeout_interruptible(round_jiffies_relative(HZ));
-		rcutorture_shutdown_absorb(title);
-	}
-}
-
 /*
  * Operations vector for selecting different types of tests.
  */
@@ -365,7 +216,7 @@ rcu_stutter_wait(const char *title)
 struct rcu_torture_ops {
 	void (*init)(void);
 	int (*readlock)(void);
-	void (*read_delay)(struct rcu_random_state *rrsp);
+	void (*read_delay)(struct torture_random_state *rrsp);
 	void (*readunlock)(int idx);
 	int (*completed)(void);
 	void (*deferred_free)(struct rcu_torture *p);
@@ -392,7 +243,7 @@ static int rcu_torture_read_lock(void) __acquires(RCU)
 	return 0;
 }
 
-static void rcu_read_delay(struct rcu_random_state *rrsp)
+static void rcu_read_delay(struct torture_random_state *rrsp)
 {
 	const unsigned long shortdelay_us = 200;
 	const unsigned long longdelay_ms = 50;
@@ -401,12 +252,13 @@ static void rcu_read_delay(struct rcu_random_state *rrsp)
 	 * period, and we want a long delay occasionally to trigger
 	 * force_quiescent_state. */
 
-	if (!(rcu_random(rrsp) % (nrealreaders * 2000 * longdelay_ms)))
+	if (!(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms)))
 		mdelay(longdelay_ms);
-	if (!(rcu_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
+	if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
 		udelay(shortdelay_us);
 #ifdef CONFIG_PREEMPT
-	if (!preempt_count() && !(rcu_random(rrsp) % (nrealreaders * 20000)))
+	if (!preempt_count() &&
+	    !(torture_random(rrsp) % (nrealreaders * 20000)))
 		preempt_schedule();  /* No QS if preempt_disable() in effect */
 #endif
 }
@@ -427,7 +279,7 @@ rcu_torture_cb(struct rcu_head *p)
 	int i;
 	struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
 
-	if (fullstop != FULLSTOP_DONTSTOP) {
+	if (torture_must_stop_irq()) {
 		/* Test is ending, just drop callbacks on the floor. */
 		/* The next initialization will pick up the pieces. */
 		return;
@@ -520,6 +372,48 @@ static struct rcu_torture_ops rcu_bh_ops = {
 };
 
 /*
+ * Don't even think about trying any of these in real life!!!
+ * The names includes "busted", and they really means it!
+ * The only purpose of these functions is to provide a buggy RCU
+ * implementation to make sure that rcutorture correctly emits
+ * buggy-RCU error messages.
+ */
+static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
+{
+	/* This is a deliberate bug for testing purposes only! */
+	rcu_torture_cb(&p->rtort_rcu);
+}
+
+static void synchronize_rcu_busted(void)
+{
+	/* This is a deliberate bug for testing purposes only! */
+}
+
+static void
+call_rcu_busted(struct rcu_head *head, void (*func)(struct rcu_head *rcu))
+{
+	/* This is a deliberate bug for testing purposes only! */
+	func(head);
+}
+
+static struct rcu_torture_ops rcu_busted_ops = {
+	.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,
+	.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"
+};
+
+/*
  * Definitions for srcu torture testing.
  */
 
@@ -530,7 +424,7 @@ static int srcu_torture_read_lock(void) __acquires(&srcu_ctl)
 	return srcu_read_lock(&srcu_ctl);
 }
 
-static void srcu_read_delay(struct rcu_random_state *rrsp)
+static void srcu_read_delay(struct torture_random_state *rrsp)
 {
 	long delay;
 	const long uspertick = 1000000 / HZ;
@@ -538,7 +432,8 @@ static void srcu_read_delay(struct rcu_random_state *rrsp)
 
 	/* We want there to be long-running readers, but not all the time. */
 
-	delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay * uspertick);
+	delay = torture_random(rrsp) %
+		(nrealreaders * 2 * longdelay * uspertick);
 	if (!delay)
 		schedule_timeout_interruptible(longdelay);
 	else
@@ -677,12 +572,12 @@ static int rcu_torture_boost(void *arg)
 	struct rcu_boost_inflight rbi = { .inflight = 0 };
 	struct sched_param sp;
 
-	VERBOSE_PRINTK_STRING("rcu_torture_boost started");
+	VERBOSE_TOROUT_STRING("rcu_torture_boost started");
 
 	/* Set real-time priority. */
 	sp.sched_priority = 1;
 	if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
-		VERBOSE_PRINTK_STRING("rcu_torture_boost RT prio failed!");
+		VERBOSE_TOROUT_STRING("rcu_torture_boost RT prio failed!");
 		n_rcu_torture_boost_rterror++;
 	}
 
@@ -693,9 +588,8 @@ static int rcu_torture_boost(void *arg)
 		oldstarttime = boost_starttime;
 		while (ULONG_CMP_LT(jiffies, oldstarttime)) {
 			schedule_timeout_interruptible(oldstarttime - jiffies);
-			rcu_stutter_wait("rcu_torture_boost");
-			if (kthread_should_stop() ||
-			    fullstop != FULLSTOP_DONTSTOP)
+			stutter_wait("rcu_torture_boost");
+			if (torture_must_stop())
 				goto checkwait;
 		}
 
@@ -710,15 +604,14 @@ static int rcu_torture_boost(void *arg)
 				call_rcu(&rbi.rcu, rcu_torture_boost_cb);
 				if (jiffies - call_rcu_time >
 					 test_boost_duration * HZ - HZ / 2) {
-					VERBOSE_PRINTK_STRING("rcu_torture_boost boosting failed");
+					VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
 					n_rcu_torture_boost_failure++;
 				}
 				call_rcu_time = jiffies;
 			}
 			cond_resched();
-			rcu_stutter_wait("rcu_torture_boost");
-			if (kthread_should_stop() ||
-			    fullstop != FULLSTOP_DONTSTOP)
+			stutter_wait("rcu_torture_boost");
+			if (torture_must_stop())
 				goto checkwait;
 		}
 
@@ -742,16 +635,17 @@ static int rcu_torture_boost(void *arg)
 		}
 
 		/* Go do the stutter. */
-checkwait:	rcu_stutter_wait("rcu_torture_boost");
-	} while (!kthread_should_stop() && fullstop  == FULLSTOP_DONTSTOP);
+checkwait:	stutter_wait("rcu_torture_boost");
+	} while (!torture_must_stop());
 
 	/* Clean up and exit. */
-	VERBOSE_PRINTK_STRING("rcu_torture_boost task stopping");
-	rcutorture_shutdown_absorb("rcu_torture_boost");
-	while (!kthread_should_stop() || rbi.inflight)
+	while (!kthread_should_stop() || rbi.inflight) {
+		torture_shutdown_absorb("rcu_torture_boost");
 		schedule_timeout_uninterruptible(1);
+	}
 	smp_mb(); /* order accesses to ->inflight before stack-frame death. */
 	destroy_rcu_head_on_stack(&rbi.rcu);
+	torture_kthread_stopping("rcu_torture_boost");
 	return 0;
 }
 
@@ -766,7 +660,7 @@ rcu_torture_fqs(void *arg)
 	unsigned long fqs_resume_time;
 	int fqs_burst_remaining;
 
-	VERBOSE_PRINTK_STRING("rcu_torture_fqs task started");
+	VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
 	do {
 		fqs_resume_time = jiffies + fqs_stutter * HZ;
 		while (ULONG_CMP_LT(jiffies, fqs_resume_time) &&
@@ -780,12 +674,9 @@ rcu_torture_fqs(void *arg)
 			udelay(fqs_holdoff);
 			fqs_burst_remaining -= fqs_holdoff;
 		}
-		rcu_stutter_wait("rcu_torture_fqs");
-	} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
-	VERBOSE_PRINTK_STRING("rcu_torture_fqs task stopping");
-	rcutorture_shutdown_absorb("rcu_torture_fqs");
-	while (!kthread_should_stop())
-		schedule_timeout_uninterruptible(1);
+		stutter_wait("rcu_torture_fqs");
+	} while (!torture_must_stop());
+	torture_kthread_stopping("rcu_torture_fqs");
 	return 0;
 }
 
@@ -802,9 +693,9 @@ rcu_torture_writer(void *arg)
 	struct rcu_torture *rp;
 	struct rcu_torture *rp1;
 	struct rcu_torture *old_rp;
-	static DEFINE_RCU_RANDOM(rand);
+	static DEFINE_TORTURE_RANDOM(rand);
 
-	VERBOSE_PRINTK_STRING("rcu_torture_writer task started");
+	VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
 	set_user_nice(current, 19);
 
 	do {
@@ -813,7 +704,7 @@ rcu_torture_writer(void *arg)
 		if (rp == NULL)
 			continue;
 		rp->rtort_pipe_count = 0;
-		udelay(rcu_random(&rand) & 0x3ff);
+		udelay(torture_random(&rand) & 0x3ff);
 		old_rp = rcu_dereference_check(rcu_torture_current,
 					       current == writer_task);
 		rp->rtort_mbtest = 1;
@@ -826,7 +717,7 @@ rcu_torture_writer(void *arg)
 			atomic_inc(&rcu_torture_wcount[i]);
 			old_rp->rtort_pipe_count++;
 			if (gp_normal == gp_exp)
-				exp = !!(rcu_random(&rand) & 0x80);
+				exp = !!(torture_random(&rand) & 0x80);
 			else
 				exp = gp_exp;
 			if (!exp) {
@@ -852,12 +743,9 @@ rcu_torture_writer(void *arg)
 			}
 		}
 		rcutorture_record_progress(++rcu_torture_current_version);
-		rcu_stutter_wait("rcu_torture_writer");
-	} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
-	VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
-	rcutorture_shutdown_absorb("rcu_torture_writer");
-	while (!kthread_should_stop())
-		schedule_timeout_uninterruptible(1);
+		stutter_wait("rcu_torture_writer");
+	} while (!torture_must_stop());
+	torture_kthread_stopping("rcu_torture_writer");
 	return 0;
 }
 
@@ -868,19 +756,19 @@ rcu_torture_writer(void *arg)
 static int
 rcu_torture_fakewriter(void *arg)
 {
-	DEFINE_RCU_RANDOM(rand);
+	DEFINE_TORTURE_RANDOM(rand);
 
-	VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started");
+	VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
 	set_user_nice(current, 19);
 
 	do {
-		schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10);
-		udelay(rcu_random(&rand) & 0x3ff);
+		schedule_timeout_uninterruptible(1 + torture_random(&rand)%10);
+		udelay(torture_random(&rand) & 0x3ff);
 		if (cur_ops->cb_barrier != NULL &&
-		    rcu_random(&rand) % (nfakewriters * 8) == 0) {
+		    torture_random(&rand) % (nfakewriters * 8) == 0) {
 			cur_ops->cb_barrier();
 		} else if (gp_normal == gp_exp) {
-			if (rcu_random(&rand) & 0x80)
+			if (torture_random(&rand) & 0x80)
 				cur_ops->sync();
 			else
 				cur_ops->exp_sync();
@@ -889,13 +777,10 @@ rcu_torture_fakewriter(void *arg)
 		} else {
 			cur_ops->exp_sync();
 		}
-		rcu_stutter_wait("rcu_torture_fakewriter");
-	} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
+		stutter_wait("rcu_torture_fakewriter");
+	} while (!torture_must_stop());
 
-	VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
-	rcutorture_shutdown_absorb("rcu_torture_fakewriter");
-	while (!kthread_should_stop())
-		schedule_timeout_uninterruptible(1);
+	torture_kthread_stopping("rcu_torture_fakewriter");
 	return 0;
 }
 
@@ -921,7 +806,7 @@ static void rcu_torture_timer(unsigned long unused)
 	int idx;
 	int completed;
 	int completed_end;
-	static DEFINE_RCU_RANDOM(rand);
+	static DEFINE_TORTURE_RANDOM(rand);
 	static DEFINE_SPINLOCK(rand_lock);
 	struct rcu_torture *p;
 	int pipe_count;
@@ -980,13 +865,13 @@ rcu_torture_reader(void *arg)
 	int completed;
 	int completed_end;
 	int idx;
-	DEFINE_RCU_RANDOM(rand);
+	DEFINE_TORTURE_RANDOM(rand);
 	struct rcu_torture *p;
 	int pipe_count;
 	struct timer_list t;
 	unsigned long long ts;
 
-	VERBOSE_PRINTK_STRING("rcu_torture_reader task started");
+	VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
 	set_user_nice(current, 19);
 	if (irqreader && cur_ops->irq_capable)
 		setup_timer_on_stack(&t, rcu_torture_timer, 0);
@@ -1034,14 +919,11 @@ rcu_torture_reader(void *arg)
 		preempt_enable();
 		cur_ops->readunlock(idx);
 		schedule();
-		rcu_stutter_wait("rcu_torture_reader");
-	} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
-	VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
-	rcutorture_shutdown_absorb("rcu_torture_reader");
+		stutter_wait("rcu_torture_reader");
+	} while (!torture_must_stop());
 	if (irqreader && cur_ops->irq_capable)
 		del_timer_sync(&t);
-	while (!kthread_should_stop())
-		schedule_timeout_uninterruptible(1);
+	torture_kthread_stopping("rcu_torture_reader");
 	return 0;
 }
 
@@ -1083,13 +965,7 @@ rcu_torture_printk(char *page)
 		       n_rcu_torture_boost_failure,
 		       n_rcu_torture_boosts,
 		       n_rcu_torture_timers);
-	page += sprintf(page,
-		       "onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ",
-		       n_online_successes, n_online_attempts,
-		       n_offline_successes, n_offline_attempts,
-		       min_online, max_online,
-		       min_offline, max_offline,
-		       sum_online, sum_offline, HZ);
+	page = torture_onoff_stats(page);
 	page += sprintf(page, "barrier: %ld/%ld:%ld",
 		       n_barrier_successes,
 		       n_barrier_attempts,
@@ -1150,123 +1026,17 @@ rcu_torture_stats_print(void)
 /*
  * Periodically prints torture statistics, if periodic statistics printing
  * was specified via the stat_interval module parameter.
- *
- * No need to worry about fullstop here, since this one doesn't reference
- * volatile state or register callbacks.
  */
 static int
 rcu_torture_stats(void *arg)
 {
-	VERBOSE_PRINTK_STRING("rcu_torture_stats task started");
+	VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
 	do {
 		schedule_timeout_interruptible(stat_interval * HZ);
 		rcu_torture_stats_print();
-		rcutorture_shutdown_absorb("rcu_torture_stats");
-	} while (!kthread_should_stop());
-	VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping");
-	return 0;
-}
-
-static int rcu_idle_cpu;	/* Force all torture tasks off this CPU */
-
-/* Shuffle tasks such that we allow @rcu_idle_cpu to become idle. A special case
- * is when @rcu_idle_cpu = -1, when we allow the tasks to run on all CPUs.
- */
-static void rcu_torture_shuffle_tasks(void)
-{
-	int i;
-
-	cpumask_setall(shuffle_tmp_mask);
-	get_online_cpus();
-
-	/* No point in shuffling if there is only one online CPU (ex: UP) */
-	if (num_online_cpus() == 1) {
-		put_online_cpus();
-		return;
-	}
-
-	if (rcu_idle_cpu != -1)
-		cpumask_clear_cpu(rcu_idle_cpu, shuffle_tmp_mask);
-
-	set_cpus_allowed_ptr(current, shuffle_tmp_mask);
-
-	if (reader_tasks) {
-		for (i = 0; i < nrealreaders; i++)
-			if (reader_tasks[i])
-				set_cpus_allowed_ptr(reader_tasks[i],
-						     shuffle_tmp_mask);
-	}
-	if (fakewriter_tasks) {
-		for (i = 0; i < nfakewriters; i++)
-			if (fakewriter_tasks[i])
-				set_cpus_allowed_ptr(fakewriter_tasks[i],
-						     shuffle_tmp_mask);
-	}
-	if (writer_task)
-		set_cpus_allowed_ptr(writer_task, shuffle_tmp_mask);
-	if (stats_task)
-		set_cpus_allowed_ptr(stats_task, shuffle_tmp_mask);
-	if (stutter_task)
-		set_cpus_allowed_ptr(stutter_task, shuffle_tmp_mask);
-	if (fqs_task)
-		set_cpus_allowed_ptr(fqs_task, shuffle_tmp_mask);
-	if (shutdown_task)
-		set_cpus_allowed_ptr(shutdown_task, shuffle_tmp_mask);
-#ifdef CONFIG_HOTPLUG_CPU
-	if (onoff_task)
-		set_cpus_allowed_ptr(onoff_task, shuffle_tmp_mask);
-#endif /* #ifdef CONFIG_HOTPLUG_CPU */
-	if (stall_task)
-		set_cpus_allowed_ptr(stall_task, shuffle_tmp_mask);
-	if (barrier_cbs_tasks)
-		for (i = 0; i < n_barrier_cbs; i++)
-			if (barrier_cbs_tasks[i])
-				set_cpus_allowed_ptr(barrier_cbs_tasks[i],
-						     shuffle_tmp_mask);
-	if (barrier_task)
-		set_cpus_allowed_ptr(barrier_task, shuffle_tmp_mask);
-
-	if (rcu_idle_cpu == -1)
-		rcu_idle_cpu = num_online_cpus() - 1;
-	else
-		rcu_idle_cpu--;
-
-	put_online_cpus();
-}
-
-/* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
- * system to become idle at a time and cut off its timer ticks. This is meant
- * to test the support for such tickless idle CPU in RCU.
- */
-static int
-rcu_torture_shuffle(void *arg)
-{
-	VERBOSE_PRINTK_STRING("rcu_torture_shuffle task started");
-	do {
-		schedule_timeout_interruptible(shuffle_interval * HZ);
-		rcu_torture_shuffle_tasks();
-		rcutorture_shutdown_absorb("rcu_torture_shuffle");
-	} while (!kthread_should_stop());
-	VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping");
-	return 0;
-}
-
-/* Cause the rcutorture test to "stutter", starting and stopping all
- * threads periodically.
- */
-static int
-rcu_torture_stutter(void *arg)
-{
-	VERBOSE_PRINTK_STRING("rcu_torture_stutter task started");
-	do {
-		schedule_timeout_interruptible(stutter * HZ);
-		stutter_pause_test = 1;
-		if (!kthread_should_stop())
-			schedule_timeout_interruptible(stutter * HZ);
-		stutter_pause_test = 0;
-		rcutorture_shutdown_absorb("rcu_torture_stutter");
-	} while (!kthread_should_stop());
-	VERBOSE_PRINTK_STRING("rcu_torture_stutter task stopping");
+		torture_shutdown_absorb("rcu_torture_stats");
+	} while (!torture_must_stop());
+	torture_kthread_stopping("rcu_torture_stats");
 	return 0;
 }
 
@@ -1293,10 +1063,6 @@ rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
 		 onoff_interval, onoff_holdoff);
 }
 
-static struct notifier_block rcutorture_shutdown_nb = {
-	.notifier_call = rcutorture_shutdown_notify,
-};
-
 static void rcutorture_booster_cleanup(int cpu)
 {
 	struct task_struct *t;
@@ -1304,14 +1070,12 @@ static void rcutorture_booster_cleanup(int cpu)
 	if (boost_tasks[cpu] == NULL)
 		return;
 	mutex_lock(&boost_mutex);
-	VERBOSE_PRINTK_STRING("Stopping rcu_torture_boost task");
 	t = boost_tasks[cpu];
 	boost_tasks[cpu] = NULL;
 	mutex_unlock(&boost_mutex);
 
 	/* This must be outside of the mutex, otherwise deadlock! */
-	kthread_stop(t);
-	boost_tasks[cpu] = NULL;
+	torture_stop_kthread(rcu_torture_boost, t);
 }
 
 static int rcutorture_booster_init(int cpu)
@@ -1323,13 +1087,13 @@ static int rcutorture_booster_init(int cpu)
 
 	/* Don't allow time recalculation while creating a new task. */
 	mutex_lock(&boost_mutex);
-	VERBOSE_PRINTK_STRING("Creating rcu_torture_boost task");
+	VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
 	boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
 						  cpu_to_node(cpu),
 						  "rcu_torture_boost");
 	if (IS_ERR(boost_tasks[cpu])) {
 		retval = PTR_ERR(boost_tasks[cpu]);
-		VERBOSE_PRINTK_STRING("rcu_torture_boost task create failed");
+		VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
 		n_rcu_torture_boost_ktrerror++;
 		boost_tasks[cpu] = NULL;
 		mutex_unlock(&boost_mutex);
@@ -1342,175 +1106,6 @@ static int rcutorture_booster_init(int cpu)
 }
 
 /*
- * Cause the rcutorture test to shutdown the system after the test has
- * run for the time specified by the shutdown_secs module parameter.
- */
-static int
-rcu_torture_shutdown(void *arg)
-{
-	long delta;
-	unsigned long jiffies_snap;
-
-	VERBOSE_PRINTK_STRING("rcu_torture_shutdown task started");
-	jiffies_snap = ACCESS_ONCE(jiffies);
-	while (ULONG_CMP_LT(jiffies_snap, shutdown_time) &&
-	       !kthread_should_stop()) {
-		delta = shutdown_time - jiffies_snap;
-		if (verbose)
-			pr_alert("%s" TORTURE_FLAG
-				 "rcu_torture_shutdown task: %lu jiffies remaining\n",
-				 torture_type, delta);
-		schedule_timeout_interruptible(delta);
-		jiffies_snap = ACCESS_ONCE(jiffies);
-	}
-	if (kthread_should_stop()) {
-		VERBOSE_PRINTK_STRING("rcu_torture_shutdown task stopping");
-		return 0;
-	}
-
-	/* OK, shut down the system. */
-
-	VERBOSE_PRINTK_STRING("rcu_torture_shutdown task shutting down system");
-	shutdown_task = NULL;	/* Avoid self-kill deadlock. */
-	rcu_torture_cleanup();	/* Get the success/failure message. */
-	kernel_power_off();	/* Shut down the system. */
-	return 0;
-}
-
-#ifdef CONFIG_HOTPLUG_CPU
-
-/*
- * Execute random CPU-hotplug operations at the interval specified
- * by the onoff_interval.
- */
-static int
-rcu_torture_onoff(void *arg)
-{
-	int cpu;
-	unsigned long delta;
-	int maxcpu = -1;
-	DEFINE_RCU_RANDOM(rand);
-	int ret;
-	unsigned long starttime;
-
-	VERBOSE_PRINTK_STRING("rcu_torture_onoff task started");
-	for_each_online_cpu(cpu)
-		maxcpu = cpu;
-	WARN_ON(maxcpu < 0);
-	if (onoff_holdoff > 0) {
-		VERBOSE_PRINTK_STRING("rcu_torture_onoff begin holdoff");
-		schedule_timeout_interruptible(onoff_holdoff * HZ);
-		VERBOSE_PRINTK_STRING("rcu_torture_onoff end holdoff");
-	}
-	while (!kthread_should_stop()) {
-		cpu = (rcu_random(&rand) >> 4) % (maxcpu + 1);
-		if (cpu_online(cpu) && cpu_is_hotpluggable(cpu)) {
-			if (verbose)
-				pr_alert("%s" TORTURE_FLAG
-					 "rcu_torture_onoff task: offlining %d\n",
-					 torture_type, cpu);
-			starttime = jiffies;
-			n_offline_attempts++;
-			ret = cpu_down(cpu);
-			if (ret) {
-				if (verbose)
-					pr_alert("%s" TORTURE_FLAG
-						 "rcu_torture_onoff task: offline %d failed: errno %d\n",
-						 torture_type, cpu, ret);
-			} else {
-				if (verbose)
-					pr_alert("%s" TORTURE_FLAG
-						 "rcu_torture_onoff task: offlined %d\n",
-						 torture_type, cpu);
-				n_offline_successes++;
-				delta = jiffies - starttime;
-				sum_offline += delta;
-				if (min_offline < 0) {
-					min_offline = delta;
-					max_offline = delta;
-				}
-				if (min_offline > delta)
-					min_offline = delta;
-				if (max_offline < delta)
-					max_offline = delta;
-			}
-		} else if (cpu_is_hotpluggable(cpu)) {
-			if (verbose)
-				pr_alert("%s" TORTURE_FLAG
-					 "rcu_torture_onoff task: onlining %d\n",
-					 torture_type, cpu);
-			starttime = jiffies;
-			n_online_attempts++;
-			ret = cpu_up(cpu);
-			if (ret) {
-				if (verbose)
-					pr_alert("%s" TORTURE_FLAG
-						 "rcu_torture_onoff task: online %d failed: errno %d\n",
-						 torture_type, cpu, ret);
-			} else {
-				if (verbose)
-					pr_alert("%s" TORTURE_FLAG
-						 "rcu_torture_onoff task: onlined %d\n",
-						 torture_type, cpu);
-				n_online_successes++;
-				delta = jiffies - starttime;
-				sum_online += delta;
-				if (min_online < 0) {
-					min_online = delta;
-					max_online = delta;
-				}
-				if (min_online > delta)
-					min_online = delta;
-				if (max_online < delta)
-					max_online = delta;
-			}
-		}
-		schedule_timeout_interruptible(onoff_interval * HZ);
-	}
-	VERBOSE_PRINTK_STRING("rcu_torture_onoff task stopping");
-	return 0;
-}
-
-static int
-rcu_torture_onoff_init(void)
-{
-	int ret;
-
-	if (onoff_interval <= 0)
-		return 0;
-	onoff_task = kthread_run(rcu_torture_onoff, NULL, "rcu_torture_onoff");
-	if (IS_ERR(onoff_task)) {
-		ret = PTR_ERR(onoff_task);
-		onoff_task = NULL;
-		return ret;
-	}
-	return 0;
-}
-
-static void rcu_torture_onoff_cleanup(void)
-{
-	if (onoff_task == NULL)
-		return;
-	VERBOSE_PRINTK_STRING("Stopping rcu_torture_onoff task");
-	kthread_stop(onoff_task);
-	onoff_task = NULL;
-}
-
-#else /* #ifdef CONFIG_HOTPLUG_CPU */
-
-static int
-rcu_torture_onoff_init(void)
-{
-	return 0;
-}
-
-static void rcu_torture_onoff_cleanup(void)
-{
-}
-
-#endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
-
-/*
  * CPU-stall kthread.  It waits as specified by stall_cpu_holdoff, then
  * induces a CPU stall for the time specified by stall_cpu.
  */
@@ -1518,11 +1113,11 @@ static int rcu_torture_stall(void *args)
 {
 	unsigned long stop_at;
 
-	VERBOSE_PRINTK_STRING("rcu_torture_stall task started");
+	VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
 	if (stall_cpu_holdoff > 0) {
-		VERBOSE_PRINTK_STRING("rcu_torture_stall begin holdoff");
+		VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
 		schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
-		VERBOSE_PRINTK_STRING("rcu_torture_stall end holdoff");
+		VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
 	}
 	if (!kthread_should_stop()) {
 		stop_at = get_seconds() + stall_cpu;
@@ -1536,7 +1131,7 @@ static int rcu_torture_stall(void *args)
 		rcu_read_unlock();
 		pr_alert("rcu_torture_stall end.\n");
 	}
-	rcutorture_shutdown_absorb("rcu_torture_stall");
+	torture_shutdown_absorb("rcu_torture_stall");
 	while (!kthread_should_stop())
 		schedule_timeout_interruptible(10 * HZ);
 	return 0;
@@ -1545,27 +1140,9 @@ static int rcu_torture_stall(void *args)
 /* Spawn CPU-stall kthread, if stall_cpu specified. */
 static int __init rcu_torture_stall_init(void)
 {
-	int ret;
-
 	if (stall_cpu <= 0)
 		return 0;
-	stall_task = kthread_run(rcu_torture_stall, NULL, "rcu_torture_stall");
-	if (IS_ERR(stall_task)) {
-		ret = PTR_ERR(stall_task);
-		stall_task = NULL;
-		return ret;
-	}
-	return 0;
-}
-
-/* Clean up after the CPU-stall kthread, if one was spawned. */
-static void rcu_torture_stall_cleanup(void)
-{
-	if (stall_task == NULL)
-		return;
-	VERBOSE_PRINTK_STRING("Stopping rcu_torture_stall_task.");
-	kthread_stop(stall_task);
-	stall_task = NULL;
+	return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
 }
 
 /* Callback function for RCU barrier testing. */
@@ -1583,28 +1160,24 @@ static int rcu_torture_barrier_cbs(void *arg)
 	struct rcu_head rcu;
 
 	init_rcu_head_on_stack(&rcu);
-	VERBOSE_PRINTK_STRING("rcu_torture_barrier_cbs task started");
+	VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
 	set_user_nice(current, 19);
 	do {
 		wait_event(barrier_cbs_wq[myid],
 			   (newphase =
 			    ACCESS_ONCE(barrier_phase)) != lastphase ||
-			   kthread_should_stop() ||
-			   fullstop != FULLSTOP_DONTSTOP);
+			   torture_must_stop());
 		lastphase = newphase;
 		smp_mb(); /* ensure barrier_phase load before ->call(). */
-		if (kthread_should_stop() || fullstop != FULLSTOP_DONTSTOP)
+		if (torture_must_stop())
 			break;
 		cur_ops->call(&rcu, rcu_torture_barrier_cbf);
 		if (atomic_dec_and_test(&barrier_cbs_count))
 			wake_up(&barrier_wq);
-	} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
-	VERBOSE_PRINTK_STRING("rcu_torture_barrier_cbs task stopping");
-	rcutorture_shutdown_absorb("rcu_torture_barrier_cbs");
-	while (!kthread_should_stop())
-		schedule_timeout_interruptible(1);
+	} while (!torture_must_stop());
 	cur_ops->cb_barrier();
 	destroy_rcu_head_on_stack(&rcu);
+	torture_kthread_stopping("rcu_torture_barrier_cbs");
 	return 0;
 }
 
@@ -1613,7 +1186,7 @@ static int rcu_torture_barrier(void *arg)
 {
 	int i;
 
-	VERBOSE_PRINTK_STRING("rcu_torture_barrier task starting");
+	VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
 	do {
 		atomic_set(&barrier_cbs_invoked, 0);
 		atomic_set(&barrier_cbs_count, n_barrier_cbs);
@@ -1623,9 +1196,8 @@ static int rcu_torture_barrier(void *arg)
 			wake_up(&barrier_cbs_wq[i]);
 		wait_event(barrier_wq,
 			   atomic_read(&barrier_cbs_count) == 0 ||
-			   kthread_should_stop() ||
-			   fullstop != FULLSTOP_DONTSTOP);
-		if (kthread_should_stop() || fullstop != FULLSTOP_DONTSTOP)
+			   torture_must_stop());
+		if (torture_must_stop())
 			break;
 		n_barrier_attempts++;
 		cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
@@ -1635,11 +1207,8 @@ static int rcu_torture_barrier(void *arg)
 		}
 		n_barrier_successes++;
 		schedule_timeout_interruptible(HZ / 10);
-	} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
-	VERBOSE_PRINTK_STRING("rcu_torture_barrier task stopping");
-	rcutorture_shutdown_absorb("rcu_torture_barrier");
-	while (!kthread_should_stop())
-		schedule_timeout_interruptible(1);
+	} while (!torture_must_stop());
+	torture_kthread_stopping("rcu_torture_barrier");
 	return 0;
 }
 
@@ -1672,24 +1241,13 @@ static int rcu_torture_barrier_init(void)
 		return -ENOMEM;
 	for (i = 0; i < n_barrier_cbs; i++) {
 		init_waitqueue_head(&barrier_cbs_wq[i]);
-		barrier_cbs_tasks[i] = kthread_run(rcu_torture_barrier_cbs,
-						   (void *)(long)i,
-						   "rcu_torture_barrier_cbs");
-		if (IS_ERR(barrier_cbs_tasks[i])) {
-			ret = PTR_ERR(barrier_cbs_tasks[i]);
-			VERBOSE_PRINTK_ERRSTRING("Failed to create rcu_torture_barrier_cbs");
-			barrier_cbs_tasks[i] = NULL;
+		ret = torture_create_kthread(rcu_torture_barrier_cbs,
+					     (void *)(long)i,
+					     barrier_cbs_tasks[i]);
+		if (ret)
 			return ret;
-		}
 	}
-	barrier_task = kthread_run(rcu_torture_barrier, NULL,
-				   "rcu_torture_barrier");
-	if (IS_ERR(barrier_task)) {
-		ret = PTR_ERR(barrier_task);
-		VERBOSE_PRINTK_ERRSTRING("Failed to create rcu_torture_barrier");
-		barrier_task = NULL;
-	}
-	return 0;
+	return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
 }
 
 /* Clean up after RCU barrier testing. */
@@ -1697,19 +1255,11 @@ static void rcu_torture_barrier_cleanup(void)
 {
 	int i;
 
-	if (barrier_task != NULL) {
-		VERBOSE_PRINTK_STRING("Stopping rcu_torture_barrier task");
-		kthread_stop(barrier_task);
-		barrier_task = NULL;
-	}
+	torture_stop_kthread(rcu_torture_barrier, barrier_task);
 	if (barrier_cbs_tasks != NULL) {
-		for (i = 0; i < n_barrier_cbs; i++) {
-			if (barrier_cbs_tasks[i] != NULL) {
-				VERBOSE_PRINTK_STRING("Stopping rcu_torture_barrier_cbs task");
-				kthread_stop(barrier_cbs_tasks[i]);
-				barrier_cbs_tasks[i] = NULL;
-			}
-		}
+		for (i = 0; i < n_barrier_cbs; i++)
+			torture_stop_kthread(rcu_torture_barrier_cbs,
+					     barrier_cbs_tasks[i]);
 		kfree(barrier_cbs_tasks);
 		barrier_cbs_tasks = NULL;
 	}
@@ -1747,90 +1297,42 @@ rcu_torture_cleanup(void)
 {
 	int i;
 
-	mutex_lock(&fullstop_mutex);
 	rcutorture_record_test_transition();
-	if (fullstop == FULLSTOP_SHUTDOWN) {
-		pr_warn(/* but going down anyway, so... */
-		       "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
-		mutex_unlock(&fullstop_mutex);
-		schedule_timeout_uninterruptible(10);
+	if (torture_cleanup()) {
 		if (cur_ops->cb_barrier != NULL)
 			cur_ops->cb_barrier();
 		return;
 	}
-	fullstop = FULLSTOP_RMMOD;
-	mutex_unlock(&fullstop_mutex);
-	unregister_reboot_notifier(&rcutorture_shutdown_nb);
-	rcu_torture_barrier_cleanup();
-	rcu_torture_stall_cleanup();
-	if (stutter_task) {
-		VERBOSE_PRINTK_STRING("Stopping rcu_torture_stutter task");
-		kthread_stop(stutter_task);
-	}
-	stutter_task = NULL;
-	if (shuffler_task) {
-		VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task");
-		kthread_stop(shuffler_task);
-		free_cpumask_var(shuffle_tmp_mask);
-	}
-	shuffler_task = NULL;
 
-	if (writer_task) {
-		VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task");
-		kthread_stop(writer_task);
-	}
-	writer_task = NULL;
+	rcu_torture_barrier_cleanup();
+	torture_stop_kthread(rcu_torture_stall, stall_task);
+	torture_stop_kthread(rcu_torture_writer, writer_task);
 
 	if (reader_tasks) {
-		for (i = 0; i < nrealreaders; i++) {
-			if (reader_tasks[i]) {
-				VERBOSE_PRINTK_STRING(
-					"Stopping rcu_torture_reader task");
-				kthread_stop(reader_tasks[i]);
-			}
-			reader_tasks[i] = NULL;
-		}
+		for (i = 0; i < nrealreaders; i++)
+			torture_stop_kthread(rcu_torture_reader,
+					     reader_tasks[i]);
 		kfree(reader_tasks);
-		reader_tasks = NULL;
 	}
 	rcu_torture_current = NULL;
 
 	if (fakewriter_tasks) {
 		for (i = 0; i < nfakewriters; i++) {
-			if (fakewriter_tasks[i]) {
-				VERBOSE_PRINTK_STRING(
-					"Stopping rcu_torture_fakewriter task");
-				kthread_stop(fakewriter_tasks[i]);
-			}
-			fakewriter_tasks[i] = NULL;
+			torture_stop_kthread(rcu_torture_fakewriter,
+					     fakewriter_tasks[i]);
 		}
 		kfree(fakewriter_tasks);
 		fakewriter_tasks = NULL;
 	}
 
-	if (stats_task) {
-		VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task");
-		kthread_stop(stats_task);
-	}
-	stats_task = NULL;
-
-	if (fqs_task) {
-		VERBOSE_PRINTK_STRING("Stopping rcu_torture_fqs task");
-		kthread_stop(fqs_task);
-	}
-	fqs_task = NULL;
+	torture_stop_kthread(rcu_torture_stats, stats_task);
+	torture_stop_kthread(rcu_torture_fqs, fqs_task);
 	if ((test_boost == 1 && cur_ops->can_boost) ||
 	    test_boost == 2) {
 		unregister_cpu_notifier(&rcutorture_cpu_nb);
 		for_each_possible_cpu(i)
 			rcutorture_booster_cleanup(i);
 	}
-	if (shutdown_task != NULL) {
-		VERBOSE_PRINTK_STRING("Stopping rcu_torture_shutdown task");
-		kthread_stop(shutdown_task);
-	}
-	shutdown_task = NULL;
-	rcu_torture_onoff_cleanup();
 
 	/* Wait for all RCU callbacks to fire.  */
 
@@ -1841,8 +1343,7 @@ rcu_torture_cleanup(void)
 
 	if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
 		rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
-	else if (n_online_successes != n_online_attempts ||
-		 n_offline_successes != n_offline_attempts)
+	else if (torture_onoff_failures())
 		rcu_torture_print_module_parms(cur_ops,
 					       "End of test: RCU_HOTPLUG");
 	else
@@ -1911,12 +1412,11 @@ rcu_torture_init(void)
 	int i;
 	int cpu;
 	int firsterr = 0;
-	int retval;
 	static struct rcu_torture_ops *torture_ops[] = {
-		&rcu_ops, &rcu_bh_ops, &srcu_ops, &sched_ops,
+		&rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &sched_ops,
 	};
 
-	mutex_lock(&fullstop_mutex);
+	torture_init_begin(torture_type, verbose, &rcutorture_runnable);
 
 	/* Process args and tell the world that the torturer is on the job. */
 	for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
@@ -1931,7 +1431,7 @@ rcu_torture_init(void)
 		for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
 			pr_alert(" %s", torture_ops[i]->name);
 		pr_alert("\n");
-		mutex_unlock(&fullstop_mutex);
+		torture_init_end();
 		return -EINVAL;
 	}
 	if (cur_ops->fqs == NULL && fqs_duration != 0) {
@@ -1946,7 +1446,6 @@ rcu_torture_init(void)
 	else
 		nrealreaders = 2 * num_online_cpus();
 	rcu_torture_print_module_parms(cur_ops, "Start of test");
-	fullstop = FULLSTOP_DONTSTOP;
 
 	/* Set up the freelist. */
 
@@ -1982,108 +1481,61 @@ rcu_torture_init(void)
 
 	/* Start up the kthreads. */
 
-	VERBOSE_PRINTK_STRING("Creating rcu_torture_writer task");
-	writer_task = kthread_create(rcu_torture_writer, NULL,
-				     "rcu_torture_writer");
-	if (IS_ERR(writer_task)) {
-		firsterr = PTR_ERR(writer_task);
-		VERBOSE_PRINTK_ERRSTRING("Failed to create writer");
-		writer_task = NULL;
+	firsterr = torture_create_kthread(rcu_torture_writer, NULL,
+					  writer_task);
+	if (firsterr)
 		goto unwind;
-	}
-	wake_up_process(writer_task);
 	fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]),
 				   GFP_KERNEL);
 	if (fakewriter_tasks == NULL) {
-		VERBOSE_PRINTK_ERRSTRING("out of memory");
+		VERBOSE_TOROUT_ERRSTRING("out of memory");
 		firsterr = -ENOMEM;
 		goto unwind;
 	}
 	for (i = 0; i < nfakewriters; i++) {
-		VERBOSE_PRINTK_STRING("Creating rcu_torture_fakewriter task");
-		fakewriter_tasks[i] = kthread_run(rcu_torture_fakewriter, NULL,
-						  "rcu_torture_fakewriter");
-		if (IS_ERR(fakewriter_tasks[i])) {
-			firsterr = PTR_ERR(fakewriter_tasks[i]);
-			VERBOSE_PRINTK_ERRSTRING("Failed to create fakewriter");
-			fakewriter_tasks[i] = NULL;
+		firsterr = torture_create_kthread(rcu_torture_fakewriter,
+						  NULL, fakewriter_tasks[i]);
+		if (firsterr)
 			goto unwind;
-		}
 	}
 	reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
 			       GFP_KERNEL);
 	if (reader_tasks == NULL) {
-		VERBOSE_PRINTK_ERRSTRING("out of memory");
+		VERBOSE_TOROUT_ERRSTRING("out of memory");
 		firsterr = -ENOMEM;
 		goto unwind;
 	}
 	for (i = 0; i < nrealreaders; i++) {
-		VERBOSE_PRINTK_STRING("Creating rcu_torture_reader task");
-		reader_tasks[i] = kthread_run(rcu_torture_reader, NULL,
-					      "rcu_torture_reader");
-		if (IS_ERR(reader_tasks[i])) {
-			firsterr = PTR_ERR(reader_tasks[i]);
-			VERBOSE_PRINTK_ERRSTRING("Failed to create reader");
-			reader_tasks[i] = NULL;
+		firsterr = torture_create_kthread(rcu_torture_reader, NULL,
+						  reader_tasks[i]);
+		if (firsterr)
 			goto unwind;
-		}
 	}
 	if (stat_interval > 0) {
-		VERBOSE_PRINTK_STRING("Creating rcu_torture_stats task");
-		stats_task = kthread_run(rcu_torture_stats, NULL,
-					"rcu_torture_stats");
-		if (IS_ERR(stats_task)) {
-			firsterr = PTR_ERR(stats_task);
-			VERBOSE_PRINTK_ERRSTRING("Failed to create stats");
-			stats_task = NULL;
+		firsterr = torture_create_kthread(rcu_torture_stats, NULL,
+						  stats_task);
+		if (firsterr)
 			goto unwind;
-		}
 	}
 	if (test_no_idle_hz) {
-		rcu_idle_cpu = num_online_cpus() - 1;
-
-		if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
-			firsterr = -ENOMEM;
-			VERBOSE_PRINTK_ERRSTRING("Failed to alloc mask");
-			goto unwind;
-		}
-
-		/* Create the shuffler thread */
-		shuffler_task = kthread_run(rcu_torture_shuffle, NULL,
-					  "rcu_torture_shuffle");
-		if (IS_ERR(shuffler_task)) {
-			free_cpumask_var(shuffle_tmp_mask);
-			firsterr = PTR_ERR(shuffler_task);
-			VERBOSE_PRINTK_ERRSTRING("Failed to create shuffler");
-			shuffler_task = NULL;
+		firsterr = torture_shuffle_init(shuffle_interval * HZ);
+		if (firsterr)
 			goto unwind;
-		}
 	}
 	if (stutter < 0)
 		stutter = 0;
 	if (stutter) {
-		/* Create the stutter thread */
-		stutter_task = kthread_run(rcu_torture_stutter, NULL,
-					  "rcu_torture_stutter");
-		if (IS_ERR(stutter_task)) {
-			firsterr = PTR_ERR(stutter_task);
-			VERBOSE_PRINTK_ERRSTRING("Failed to create stutter");
-			stutter_task = NULL;
+		firsterr = torture_stutter_init(stutter * HZ);
+		if (firsterr)
 			goto unwind;
-		}
 	}
 	if (fqs_duration < 0)
 		fqs_duration = 0;
 	if (fqs_duration) {
-		/* Create the stutter thread */
-		fqs_task = kthread_run(rcu_torture_fqs, NULL,
-				       "rcu_torture_fqs");
-		if (IS_ERR(fqs_task)) {
-			firsterr = PTR_ERR(fqs_task);
-			VERBOSE_PRINTK_ERRSTRING("Failed to create fqs");
-			fqs_task = NULL;
+		/* Create the fqs thread */
+		torture_create_kthread(rcu_torture_fqs, NULL, fqs_task);
+		if (firsterr)
 			goto unwind;
-		}
 	}
 	if (test_boost_interval < 1)
 		test_boost_interval = 1;
@@ -2097,49 +1549,31 @@ rcu_torture_init(void)
 		for_each_possible_cpu(i) {
 			if (cpu_is_offline(i))
 				continue;  /* Heuristic: CPU can go offline. */
-			retval = rcutorture_booster_init(i);
-			if (retval < 0) {
-				firsterr = retval;
+			firsterr = rcutorture_booster_init(i);
+			if (firsterr)
 				goto unwind;
-			}
 		}
 	}
-	if (shutdown_secs > 0) {
-		shutdown_time = jiffies + shutdown_secs * HZ;
-		shutdown_task = kthread_create(rcu_torture_shutdown, NULL,
-					       "rcu_torture_shutdown");
-		if (IS_ERR(shutdown_task)) {
-			firsterr = PTR_ERR(shutdown_task);
-			VERBOSE_PRINTK_ERRSTRING("Failed to create shutdown");
-			shutdown_task = NULL;
-			goto unwind;
-		}
-		wake_up_process(shutdown_task);
-	}
-	i = rcu_torture_onoff_init();
-	if (i != 0) {
-		firsterr = i;
+	firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
+	if (firsterr)
 		goto unwind;
-	}
-	register_reboot_notifier(&rcutorture_shutdown_nb);
-	i = rcu_torture_stall_init();
-	if (i != 0) {
-		firsterr = i;
+	firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval * HZ);
+	if (firsterr)
 		goto unwind;
-	}
-	retval = rcu_torture_barrier_init();
-	if (retval != 0) {
-		firsterr = retval;
+	firsterr = rcu_torture_stall_init();
+	if (firsterr)
+		goto unwind;
+	firsterr = rcu_torture_barrier_init();
+	if (firsterr)
 		goto unwind;
-	}
 	if (object_debug)
 		rcu_test_debug_objects();
 	rcutorture_record_test_transition();
-	mutex_unlock(&fullstop_mutex);
+	torture_init_end();
 	return 0;
 
 unwind:
-	mutex_unlock(&fullstop_mutex);
+	torture_init_end();
 	rcu_torture_cleanup();
 	return firsterr;
 }
diff --git a/kernel/rcu/srcu.c b/kernel/rcu/srcu.c
index 3318d8284384..c639556f3fa0 100644
--- a/kernel/rcu/srcu.c
+++ b/kernel/rcu/srcu.c
@@ -12,8 +12,8 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ * along with this program; if not, you can access it online at
+ * http://www.gnu.org/licenses/gpl-2.0.html.
  *
  * Copyright (C) IBM Corporation, 2006
  * Copyright (C) Fujitsu, 2012
@@ -36,8 +36,6 @@
 #include <linux/delay.h>
 #include <linux/srcu.h>
 
-#include <trace/events/rcu.h>
-
 #include "rcu.h"
 
 /*
@@ -398,7 +396,7 @@ void call_srcu(struct srcu_struct *sp, struct rcu_head *head,
 	rcu_batch_queue(&sp->batch_queue, head);
 	if (!sp->running) {
 		sp->running = true;
-		schedule_delayed_work(&sp->work, 0);
+		queue_delayed_work(system_power_efficient_wq, &sp->work, 0);
 	}
 	spin_unlock_irqrestore(&sp->queue_lock, flags);
 }
@@ -674,7 +672,8 @@ static void srcu_reschedule(struct srcu_struct *sp)
 	}
 
 	if (pending)
-		schedule_delayed_work(&sp->work, SRCU_INTERVAL);
+		queue_delayed_work(system_power_efficient_wq,
+				   &sp->work, SRCU_INTERVAL);
 }
 
 /*
diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c
index 1254f312d024..d9efcc13008c 100644
--- a/kernel/rcu/tiny.c
+++ b/kernel/rcu/tiny.c
@@ -12,8 +12,8 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ * along with this program; if not, you can access it online at
+ * http://www.gnu.org/licenses/gpl-2.0.html.
  *
  * Copyright IBM Corporation, 2008
  *
@@ -37,10 +37,6 @@
 #include <linux/prefetch.h>
 #include <linux/ftrace_event.h>
 
-#ifdef CONFIG_RCU_TRACE
-#include <trace/events/rcu.h>
-#endif /* #else #ifdef CONFIG_RCU_TRACE */
-
 #include "rcu.h"
 
 /* Forward declarations for tiny_plugin.h. */
diff --git a/kernel/rcu/tiny_plugin.h b/kernel/rcu/tiny_plugin.h
index 280d06cae352..431528520562 100644
--- a/kernel/rcu/tiny_plugin.h
+++ b/kernel/rcu/tiny_plugin.h
@@ -14,8 +14,8 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ * along with this program; if not, you can access it online at
+ * http://www.gnu.org/licenses/gpl-2.0.html.
  *
  * Copyright (c) 2010 Linaro
  *
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index b3d116cd072d..0c47e300210a 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -12,8 +12,8 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ * along with this program; if not, you can access it online at
+ * http://www.gnu.org/licenses/gpl-2.0.html.
  *
  * Copyright IBM Corporation, 2008
  *
@@ -58,8 +58,6 @@
 #include <linux/suspend.h>
 
 #include "tree.h"
-#include <trace/events/rcu.h>
-
 #include "rcu.h"
 
 MODULE_ALIAS("rcutree");
@@ -837,7 +835,7 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp,
 	 * to the next.  Only do this for the primary flavor of RCU.
 	 */
 	if (rdp->rsp == rcu_state &&
-	    ULONG_CMP_GE(ACCESS_ONCE(jiffies), rdp->rsp->jiffies_resched)) {
+	    ULONG_CMP_GE(jiffies, rdp->rsp->jiffies_resched)) {
 		rdp->rsp->jiffies_resched += 5;
 		resched_cpu(rdp->cpu);
 	}
@@ -847,7 +845,7 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp,
 
 static void record_gp_stall_check_time(struct rcu_state *rsp)
 {
-	unsigned long j = ACCESS_ONCE(jiffies);
+	unsigned long j = jiffies;
 	unsigned long j1;
 
 	rsp->gp_start = j;
@@ -1005,7 +1003,7 @@ static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp)
 
 	if (rcu_cpu_stall_suppress || !rcu_gp_in_progress(rsp))
 		return;
-	j = ACCESS_ONCE(jiffies);
+	j = jiffies;
 
 	/*
 	 * Lots of memory barriers to reject false positives.
@@ -1423,13 +1421,14 @@ static int rcu_gp_init(struct rcu_state *rsp)
 
 	/* Advance to a new grace period and initialize state. */
 	record_gp_stall_check_time(rsp);
-	smp_wmb(); /* Record GP times before starting GP. */
-	rsp->gpnum++;
+	/* Record GP times before starting GP, hence smp_store_release(). */
+	smp_store_release(&rsp->gpnum, rsp->gpnum + 1);
 	trace_rcu_grace_period(rsp->name, rsp->gpnum, TPS("start"));
 	raw_spin_unlock_irq(&rnp->lock);
 
 	/* Exclude any concurrent CPU-hotplug operations. */
 	mutex_lock(&rsp->onoff_mutex);
+	smp_mb__after_unlock_lock(); /* ->gpnum increment before GP! */
 
 	/*
 	 * Set the quiescent-state-needed bits in all the rcu_node
@@ -1557,10 +1556,11 @@ static void rcu_gp_cleanup(struct rcu_state *rsp)
 	}
 	rnp = rcu_get_root(rsp);
 	raw_spin_lock_irq(&rnp->lock);
-	smp_mb__after_unlock_lock();
+	smp_mb__after_unlock_lock(); /* Order GP before ->completed update. */
 	rcu_nocb_gp_set(rnp, nocb);
 
-	rsp->completed = rsp->gpnum; /* Declare grace period done. */
+	/* Declare grace period done. */
+	ACCESS_ONCE(rsp->completed) = rsp->gpnum;
 	trace_rcu_grace_period(rsp->name, rsp->completed, TPS("end"));
 	rsp->fqs_state = RCU_GP_IDLE;
 	rdp = this_cpu_ptr(rsp->rda);
@@ -2304,7 +2304,7 @@ static void force_quiescent_state(struct rcu_state *rsp)
 		if (rnp_old != NULL)
 			raw_spin_unlock(&rnp_old->fqslock);
 		if (ret) {
-			rsp->n_force_qs_lh++;
+			ACCESS_ONCE(rsp->n_force_qs_lh)++;
 			return;
 		}
 		rnp_old = rnp;
@@ -2316,7 +2316,7 @@ static void force_quiescent_state(struct rcu_state *rsp)
 	smp_mb__after_unlock_lock();
 	raw_spin_unlock(&rnp_old->fqslock);
 	if (ACCESS_ONCE(rsp->gp_flags) & RCU_GP_FLAG_FQS) {
-		rsp->n_force_qs_lh++;
+		ACCESS_ONCE(rsp->n_force_qs_lh)++;
 		raw_spin_unlock_irqrestore(&rnp_old->lock, flags);
 		return;  /* Someone beat us to it. */
 	}
@@ -2639,6 +2639,58 @@ void synchronize_rcu_bh(void)
 }
 EXPORT_SYMBOL_GPL(synchronize_rcu_bh);
 
+/**
+ * get_state_synchronize_rcu - Snapshot current RCU state
+ *
+ * Returns a cookie that is used by a later call to cond_synchronize_rcu()
+ * to determine whether or not a full grace period has elapsed in the
+ * meantime.
+ */
+unsigned long get_state_synchronize_rcu(void)
+{
+	/*
+	 * Any prior manipulation of RCU-protected data must happen
+	 * before the load from ->gpnum.
+	 */
+	smp_mb();  /* ^^^ */
+
+	/*
+	 * Make sure this load happens before the purportedly
+	 * time-consuming work between get_state_synchronize_rcu()
+	 * and cond_synchronize_rcu().
+	 */
+	return smp_load_acquire(&rcu_state->gpnum);
+}
+EXPORT_SYMBOL_GPL(get_state_synchronize_rcu);
+
+/**
+ * cond_synchronize_rcu - Conditionally wait for an RCU grace period
+ *
+ * @oldstate: return value from earlier call to get_state_synchronize_rcu()
+ *
+ * If a full RCU grace period has elapsed since the earlier call to
+ * get_state_synchronize_rcu(), just return.  Otherwise, invoke
+ * synchronize_rcu() to wait for a full grace period.
+ *
+ * Yes, this function does not take counter wrap into account.  But
+ * counter wrap is harmless.  If the counter wraps, we have waited for
+ * more than 2 billion grace periods (and way more on a 64-bit system!),
+ * so waiting for one additional grace period should be just fine.
+ */
+void cond_synchronize_rcu(unsigned long oldstate)
+{
+	unsigned long newstate;
+
+	/*
+	 * Ensure that this load happens before any RCU-destructive
+	 * actions the caller might carry out after we return.
+	 */
+	newstate = smp_load_acquire(&rcu_state->completed);
+	if (ULONG_CMP_GE(oldstate, newstate))
+		synchronize_rcu();
+}
+EXPORT_SYMBOL_GPL(cond_synchronize_rcu);
+
 static int synchronize_sched_expedited_cpu_stop(void *data)
 {
 	/*
@@ -2880,7 +2932,7 @@ static int rcu_pending(int cpu)
  * non-NULL, store an indication of whether all callbacks are lazy.
  * (If there are no callbacks, all of them are deemed to be lazy.)
  */
-static int rcu_cpu_has_callbacks(int cpu, bool *all_lazy)
+static int __maybe_unused rcu_cpu_has_callbacks(int cpu, bool *all_lazy)
 {
 	bool al = true;
 	bool hc = false;
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 8c19873f1ac9..75dc3c39a02a 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -13,8 +13,8 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ * along with this program; if not, you can access it online at
+ * http://www.gnu.org/licenses/gpl-2.0.html.
  *
  * Copyright IBM Corporation, 2008
  *
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 6e2ef4b2b920..962d1d589929 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -14,8 +14,8 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ * along with this program; if not, you can access it online at
+ * http://www.gnu.org/licenses/gpl-2.0.html.
  *
  * Copyright Red Hat, 2009
  * Copyright IBM Corporation, 2009
@@ -1586,11 +1586,13 @@ static void rcu_prepare_kthreads(int cpu)
  * Because we not have RCU_FAST_NO_HZ, just check whether this CPU needs
  * any flavor of RCU.
  */
+#ifndef CONFIG_RCU_NOCB_CPU_ALL
 int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies)
 {
 	*delta_jiffies = ULONG_MAX;
 	return rcu_cpu_has_callbacks(cpu, NULL);
 }
+#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
 
 /*
  * Because we do not have RCU_FAST_NO_HZ, don't bother cleaning up
@@ -1656,7 +1658,7 @@ extern int tick_nohz_active;
  * only if it has been awhile since the last time we did so.  Afterwards,
  * if there are any callbacks ready for immediate invocation, return true.
  */
-static bool rcu_try_advance_all_cbs(void)
+static bool __maybe_unused rcu_try_advance_all_cbs(void)
 {
 	bool cbs_ready = false;
 	struct rcu_data *rdp;
@@ -1696,6 +1698,7 @@ static bool rcu_try_advance_all_cbs(void)
  *
  * The caller must have disabled interrupts.
  */
+#ifndef CONFIG_RCU_NOCB_CPU_ALL
 int rcu_needs_cpu(int cpu, unsigned long *dj)
 {
 	struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu);
@@ -1726,6 +1729,7 @@ int rcu_needs_cpu(int cpu, unsigned long *dj)
 	}
 	return 0;
 }
+#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
 
 /*
  * Prepare a CPU for idle from an RCU perspective.  The first major task
@@ -1739,6 +1743,7 @@ int rcu_needs_cpu(int cpu, unsigned long *dj)
  */
 static void rcu_prepare_for_idle(int cpu)
 {
+#ifndef CONFIG_RCU_NOCB_CPU_ALL
 	struct rcu_data *rdp;
 	struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu);
 	struct rcu_node *rnp;
@@ -1790,6 +1795,7 @@ static void rcu_prepare_for_idle(int cpu)
 		rcu_accelerate_cbs(rsp, rnp, rdp);
 		raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */
 	}
+#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
 }
 
 /*
@@ -1799,11 +1805,12 @@ static void rcu_prepare_for_idle(int cpu)
  */
 static void rcu_cleanup_after_idle(int cpu)
 {
-
+#ifndef CONFIG_RCU_NOCB_CPU_ALL
 	if (rcu_is_nocb_cpu(cpu))
 		return;
 	if (rcu_try_advance_all_cbs())
 		invoke_rcu_core();
+#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
 }
 
 /*
@@ -2101,6 +2108,7 @@ static void rcu_init_one_nocb(struct rcu_node *rnp)
 	init_waitqueue_head(&rnp->nocb_gp_wq[1]);
 }
 
+#ifndef CONFIG_RCU_NOCB_CPU_ALL
 /* Is the specified CPU a no-CPUs CPU? */
 bool rcu_is_nocb_cpu(int cpu)
 {
@@ -2108,6 +2116,7 @@ bool rcu_is_nocb_cpu(int cpu)
 		return cpumask_test_cpu(cpu, rcu_nocb_mask);
 	return false;
 }
+#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
 
 /*
  * Enqueue the specified string of rcu_head structures onto the specified
@@ -2893,7 +2902,7 @@ static void rcu_sysidle_init_percpu_data(struct rcu_dynticks *rdtp)
  * CPU unless the grace period has extended for too long.
  *
  * This code relies on the fact that all NO_HZ_FULL CPUs are also
- * CONFIG_RCU_NOCB_CPUs.
+ * CONFIG_RCU_NOCB_CPU CPUs.
  */
 static bool rcu_nohz_full_cpu(struct rcu_state *rsp)
 {
diff --git a/kernel/rcu/tree_trace.c b/kernel/rcu/tree_trace.c
index 4def475336d4..5cdc62e1beeb 100644
--- a/kernel/rcu/tree_trace.c
+++ b/kernel/rcu/tree_trace.c
@@ -12,8 +12,8 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ * along with this program; if not, you can access it online at
+ * http://www.gnu.org/licenses/gpl-2.0.html.
  *
  * Copyright IBM Corporation, 2008
  *
@@ -273,7 +273,7 @@ static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
 	seq_printf(m, "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld/%ld\n",
 		   rsp->n_force_qs, rsp->n_force_qs_ngp,
 		   rsp->n_force_qs - rsp->n_force_qs_ngp,
-		   rsp->n_force_qs_lh, rsp->qlen_lazy, rsp->qlen);
+		   ACCESS_ONCE(rsp->n_force_qs_lh), rsp->qlen_lazy, rsp->qlen);
 	for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < rcu_num_nodes; rnp++) {
 		if (rnp->level != level) {
 			seq_puts(m, "\n");
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index c54609faf233..4c0a9b0af469 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -12,8 +12,8 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ * along with this program; if not, you can access it online at
+ * http://www.gnu.org/licenses/gpl-2.0.html.
  *
  * Copyright IBM Corporation, 2001
  *
@@ -49,7 +49,6 @@
 #include <linux/module.h>
 
 #define CREATE_TRACE_POINTS
-#include <trace/events/rcu.h>
 
 #include "rcu.h"
 
diff --git a/kernel/torture.c b/kernel/torture.c
new file mode 100644
index 000000000000..acc9afc2f26e
--- /dev/null
+++ b/kernel/torture.c
@@ -0,0 +1,719 @@
+/*
+ * Common functions for in-kernel torture tests.
+ *
+ * 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
+ * along with this program; if not, you can access it online at
+ * http://www.gnu.org/licenses/gpl-2.0.html.
+ *
+ * Copyright (C) IBM Corporation, 2014
+ *
+ * Author: Paul E. McKenney <paulmck@us.ibm.com>
+ *	Based on kernel/rcu/torture.c.
+ */
+#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/interrupt.h>
+#include <linux/sched.h>
+#include <linux/atomic.h>
+#include <linux/bitops.h>
+#include <linux/completion.h>
+#include <linux/moduleparam.h>
+#include <linux/percpu.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/freezer.h>
+#include <linux/cpu.h>
+#include <linux/delay.h>
+#include <linux/stat.h>
+#include <linux/slab.h>
+#include <linux/trace_clock.h>
+#include <asm/byteorder.h>
+#include <linux/torture.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
+
+static char *torture_type;
+static bool verbose;
+
+/* Mediate rmmod and system shutdown.  Concurrent rmmod & shutdown illegal! */
+#define FULLSTOP_DONTSTOP 0	/* Normal operation. */
+#define FULLSTOP_SHUTDOWN 1	/* System shutdown with torture running. */
+#define FULLSTOP_RMMOD    2	/* Normal rmmod of torture. */
+static int fullstop = FULLSTOP_RMMOD;
+static DEFINE_MUTEX(fullstop_mutex);
+static int *torture_runnable;
+
+#ifdef CONFIG_HOTPLUG_CPU
+
+/*
+ * Variables for online-offline handling.  Only present if CPU hotplug
+ * is enabled, otherwise does nothing.
+ */
+
+static struct task_struct *onoff_task;
+static long onoff_holdoff;
+static long onoff_interval;
+static long n_offline_attempts;
+static long n_offline_successes;
+static unsigned long sum_offline;
+static int min_offline = -1;
+static int max_offline;
+static long n_online_attempts;
+static long n_online_successes;
+static unsigned long sum_online;
+static int min_online = -1;
+static int max_online;
+
+/*
+ * Execute random CPU-hotplug operations at the interval specified
+ * by the onoff_interval.
+ */
+static int
+torture_onoff(void *arg)
+{
+	int cpu;
+	unsigned long delta;
+	int maxcpu = -1;
+	DEFINE_TORTURE_RANDOM(rand);
+	int ret;
+	unsigned long starttime;
+
+	VERBOSE_TOROUT_STRING("torture_onoff task started");
+	for_each_online_cpu(cpu)
+		maxcpu = cpu;
+	WARN_ON(maxcpu < 0);
+	if (onoff_holdoff > 0) {
+		VERBOSE_TOROUT_STRING("torture_onoff begin holdoff");
+		schedule_timeout_interruptible(onoff_holdoff);
+		VERBOSE_TOROUT_STRING("torture_onoff end holdoff");
+	}
+	while (!torture_must_stop()) {
+		cpu = (torture_random(&rand) >> 4) % (maxcpu + 1);
+		if (cpu_online(cpu) && cpu_is_hotpluggable(cpu)) {
+			if (verbose)
+				pr_alert("%s" TORTURE_FLAG
+					 "torture_onoff task: offlining %d\n",
+					 torture_type, cpu);
+			starttime = jiffies;
+			n_offline_attempts++;
+			ret = cpu_down(cpu);
+			if (ret) {
+				if (verbose)
+					pr_alert("%s" TORTURE_FLAG
+						 "torture_onoff task: offline %d failed: errno %d\n",
+						 torture_type, cpu, ret);
+			} else {
+				if (verbose)
+					pr_alert("%s" TORTURE_FLAG
+						 "torture_onoff task: offlined %d\n",
+						 torture_type, cpu);
+				n_offline_successes++;
+				delta = jiffies - starttime;
+				sum_offline += delta;
+				if (min_offline < 0) {
+					min_offline = delta;
+					max_offline = delta;
+				}
+				if (min_offline > delta)
+					min_offline = delta;
+				if (max_offline < delta)
+					max_offline = delta;
+			}
+		} else if (cpu_is_hotpluggable(cpu)) {
+			if (verbose)
+				pr_alert("%s" TORTURE_FLAG
+					 "torture_onoff task: onlining %d\n",
+					 torture_type, cpu);
+			starttime = jiffies;
+			n_online_attempts++;
+			ret = cpu_up(cpu);
+			if (ret) {
+				if (verbose)
+					pr_alert("%s" TORTURE_FLAG
+						 "torture_onoff task: online %d failed: errno %d\n",
+						 torture_type, cpu, ret);
+			} else {
+				if (verbose)
+					pr_alert("%s" TORTURE_FLAG
+						 "torture_onoff task: onlined %d\n",
+						 torture_type, cpu);
+				n_online_successes++;
+				delta = jiffies - starttime;
+				sum_online += delta;
+				if (min_online < 0) {
+					min_online = delta;
+					max_online = delta;
+				}
+				if (min_online > delta)
+					min_online = delta;
+				if (max_online < delta)
+					max_online = delta;
+			}
+		}
+		schedule_timeout_interruptible(onoff_interval);
+	}
+	torture_kthread_stopping("torture_onoff");
+	return 0;
+}
+
+#endif /* #ifdef CONFIG_HOTPLUG_CPU */
+
+/*
+ * Initiate online-offline handling.
+ */
+int torture_onoff_init(long ooholdoff, long oointerval)
+{
+	int ret = 0;
+
+#ifdef CONFIG_HOTPLUG_CPU
+	onoff_holdoff = ooholdoff;
+	onoff_interval = oointerval;
+	if (onoff_interval <= 0)
+		return 0;
+	ret = torture_create_kthread(torture_onoff, NULL, onoff_task);
+#endif /* #ifdef CONFIG_HOTPLUG_CPU */
+	return ret;
+}
+EXPORT_SYMBOL_GPL(torture_onoff_init);
+
+/*
+ * Clean up after online/offline testing.
+ */
+static void torture_onoff_cleanup(void)
+{
+#ifdef CONFIG_HOTPLUG_CPU
+	if (onoff_task == NULL)
+		return;
+	VERBOSE_TOROUT_STRING("Stopping torture_onoff task");
+	kthread_stop(onoff_task);
+	onoff_task = NULL;
+#endif /* #ifdef CONFIG_HOTPLUG_CPU */
+}
+EXPORT_SYMBOL_GPL(torture_onoff_cleanup);
+
+/*
+ * Print online/offline testing statistics.
+ */
+char *torture_onoff_stats(char *page)
+{
+#ifdef CONFIG_HOTPLUG_CPU
+	page += sprintf(page,
+		       "onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ",
+		       n_online_successes, n_online_attempts,
+		       n_offline_successes, n_offline_attempts,
+		       min_online, max_online,
+		       min_offline, max_offline,
+		       sum_online, sum_offline, HZ);
+#endif /* #ifdef CONFIG_HOTPLUG_CPU */
+	return page;
+}
+EXPORT_SYMBOL_GPL(torture_onoff_stats);
+
+/*
+ * Were all the online/offline operations successful?
+ */
+bool torture_onoff_failures(void)
+{
+#ifdef CONFIG_HOTPLUG_CPU
+	return n_online_successes != n_online_attempts ||
+	       n_offline_successes != n_offline_attempts;
+#else /* #ifdef CONFIG_HOTPLUG_CPU */
+	return false;
+#endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
+}
+EXPORT_SYMBOL_GPL(torture_onoff_failures);
+
+#define TORTURE_RANDOM_MULT	39916801  /* prime */
+#define TORTURE_RANDOM_ADD	479001701 /* prime */
+#define TORTURE_RANDOM_REFRESH	10000
+
+/*
+ * Crude but fast random-number generator.  Uses a linear congruential
+ * generator, with occasional help from cpu_clock().
+ */
+unsigned long
+torture_random(struct torture_random_state *trsp)
+{
+	if (--trsp->trs_count < 0) {
+		trsp->trs_state += (unsigned long)local_clock();
+		trsp->trs_count = TORTURE_RANDOM_REFRESH;
+	}
+	trsp->trs_state = trsp->trs_state * TORTURE_RANDOM_MULT +
+		TORTURE_RANDOM_ADD;
+	return swahw32(trsp->trs_state);
+}
+EXPORT_SYMBOL_GPL(torture_random);
+
+/*
+ * Variables for shuffling.  The idea is to ensure that each CPU stays
+ * idle for an extended period to test interactions with dyntick idle,
+ * as well as interactions with any per-CPU varibles.
+ */
+struct shuffle_task {
+	struct list_head st_l;
+	struct task_struct *st_t;
+};
+
+static long shuffle_interval;	/* In jiffies. */
+static struct task_struct *shuffler_task;
+static cpumask_var_t shuffle_tmp_mask;
+static int shuffle_idle_cpu;	/* Force all torture tasks off this CPU */
+static struct list_head shuffle_task_list = LIST_HEAD_INIT(shuffle_task_list);
+static DEFINE_MUTEX(shuffle_task_mutex);
+
+/*
+ * Register a task to be shuffled.  If there is no memory, just splat
+ * and don't bother registering.
+ */
+void torture_shuffle_task_register(struct task_struct *tp)
+{
+	struct shuffle_task *stp;
+
+	if (WARN_ON_ONCE(tp == NULL))
+		return;
+	stp = kmalloc(sizeof(*stp), GFP_KERNEL);
+	if (WARN_ON_ONCE(stp == NULL))
+		return;
+	stp->st_t = tp;
+	mutex_lock(&shuffle_task_mutex);
+	list_add(&stp->st_l, &shuffle_task_list);
+	mutex_unlock(&shuffle_task_mutex);
+}
+EXPORT_SYMBOL_GPL(torture_shuffle_task_register);
+
+/*
+ * Unregister all tasks, for example, at the end of the torture run.
+ */
+static void torture_shuffle_task_unregister_all(void)
+{
+	struct shuffle_task *stp;
+	struct shuffle_task *p;
+
+	mutex_lock(&shuffle_task_mutex);
+	list_for_each_entry_safe(stp, p, &shuffle_task_list, st_l) {
+		list_del(&stp->st_l);
+		kfree(stp);
+	}
+	mutex_unlock(&shuffle_task_mutex);
+}
+
+/* Shuffle tasks such that we allow shuffle_idle_cpu to become idle.
+ * A special case is when shuffle_idle_cpu = -1, in which case we allow
+ * the tasks to run on all CPUs.
+ */
+static void torture_shuffle_tasks(void)
+{
+	struct shuffle_task *stp;
+
+	cpumask_setall(shuffle_tmp_mask);
+	get_online_cpus();
+
+	/* No point in shuffling if there is only one online CPU (ex: UP) */
+	if (num_online_cpus() == 1) {
+		put_online_cpus();
+		return;
+	}
+
+	/* Advance to the next CPU.  Upon overflow, don't idle any CPUs. */
+	shuffle_idle_cpu = cpumask_next(shuffle_idle_cpu, shuffle_tmp_mask);
+	if (shuffle_idle_cpu >= nr_cpu_ids)
+		shuffle_idle_cpu = -1;
+	if (shuffle_idle_cpu != -1) {
+		cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask);
+		if (cpumask_empty(shuffle_tmp_mask)) {
+			put_online_cpus();
+			return;
+		}
+	}
+
+	mutex_lock(&shuffle_task_mutex);
+	list_for_each_entry(stp, &shuffle_task_list, st_l)
+		set_cpus_allowed_ptr(stp->st_t, shuffle_tmp_mask);
+	mutex_unlock(&shuffle_task_mutex);
+
+	put_online_cpus();
+}
+
+/* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
+ * system to become idle at a time and cut off its timer ticks. This is meant
+ * to test the support for such tickless idle CPU in RCU.
+ */
+static int torture_shuffle(void *arg)
+{
+	VERBOSE_TOROUT_STRING("torture_shuffle task started");
+	do {
+		schedule_timeout_interruptible(shuffle_interval);
+		torture_shuffle_tasks();
+		torture_shutdown_absorb("torture_shuffle");
+	} while (!torture_must_stop());
+	torture_kthread_stopping("torture_shuffle");
+	return 0;
+}
+
+/*
+ * Start the shuffler, with shuffint in jiffies.
+ */
+int torture_shuffle_init(long shuffint)
+{
+	shuffle_interval = shuffint;
+
+	shuffle_idle_cpu = -1;
+
+	if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
+		VERBOSE_TOROUT_ERRSTRING("Failed to alloc mask");
+		return -ENOMEM;
+	}
+
+	/* Create the shuffler thread */
+	return torture_create_kthread(torture_shuffle, NULL, shuffler_task);
+}
+EXPORT_SYMBOL_GPL(torture_shuffle_init);
+
+/*
+ * Stop the shuffling.
+ */
+static void torture_shuffle_cleanup(void)
+{
+	torture_shuffle_task_unregister_all();
+	if (shuffler_task) {
+		VERBOSE_TOROUT_STRING("Stopping torture_shuffle task");
+		kthread_stop(shuffler_task);
+		free_cpumask_var(shuffle_tmp_mask);
+	}
+	shuffler_task = NULL;
+}
+EXPORT_SYMBOL_GPL(torture_shuffle_cleanup);
+
+/*
+ * Variables for auto-shutdown.  This allows "lights out" torture runs
+ * to be fully scripted.
+ */
+static int shutdown_secs;		/* desired test duration in seconds. */
+static struct task_struct *shutdown_task;
+static unsigned long shutdown_time;	/* jiffies to system shutdown. */
+static void (*torture_shutdown_hook)(void);
+
+/*
+ * Absorb kthreads into a kernel function that won't return, so that
+ * they won't ever access module text or data again.
+ */
+void torture_shutdown_absorb(const char *title)
+{
+	while (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
+		pr_notice("torture thread %s parking due to system shutdown\n",
+			  title);
+		schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
+	}
+}
+EXPORT_SYMBOL_GPL(torture_shutdown_absorb);
+
+/*
+ * Cause the torture test to shutdown the system after the test has
+ * run for the time specified by the shutdown_secs parameter.
+ */
+static int torture_shutdown(void *arg)
+{
+	long delta;
+	unsigned long jiffies_snap;
+
+	VERBOSE_TOROUT_STRING("torture_shutdown task started");
+	jiffies_snap = jiffies;
+	while (ULONG_CMP_LT(jiffies_snap, shutdown_time) &&
+	       !torture_must_stop()) {
+		delta = shutdown_time - jiffies_snap;
+		if (verbose)
+			pr_alert("%s" TORTURE_FLAG
+				 "torture_shutdown task: %lu jiffies remaining\n",
+				 torture_type, delta);
+		schedule_timeout_interruptible(delta);
+		jiffies_snap = jiffies;
+	}
+	if (torture_must_stop()) {
+		torture_kthread_stopping("torture_shutdown");
+		return 0;
+	}
+
+	/* OK, shut down the system. */
+
+	VERBOSE_TOROUT_STRING("torture_shutdown task shutting down system");
+	shutdown_task = NULL;	/* Avoid self-kill deadlock. */
+	if (torture_shutdown_hook)
+		torture_shutdown_hook();
+	else
+		VERBOSE_TOROUT_STRING("No torture_shutdown_hook(), skipping.");
+	kernel_power_off();	/* Shut down the system. */
+	return 0;
+}
+
+/*
+ * Start up the shutdown task.
+ */
+int torture_shutdown_init(int ssecs, void (*cleanup)(void))
+{
+	int ret = 0;
+
+	shutdown_secs = ssecs;
+	torture_shutdown_hook = cleanup;
+	if (shutdown_secs > 0) {
+		shutdown_time = jiffies + shutdown_secs * HZ;
+		ret = torture_create_kthread(torture_shutdown, NULL,
+					     shutdown_task);
+	}
+	return ret;
+}
+EXPORT_SYMBOL_GPL(torture_shutdown_init);
+
+/*
+ * Detect and respond to a system shutdown.
+ */
+static int torture_shutdown_notify(struct notifier_block *unused1,
+				   unsigned long unused2, void *unused3)
+{
+	mutex_lock(&fullstop_mutex);
+	if (ACCESS_ONCE(fullstop) == FULLSTOP_DONTSTOP) {
+		VERBOSE_TOROUT_STRING("Unscheduled system shutdown detected");
+		ACCESS_ONCE(fullstop) = FULLSTOP_SHUTDOWN;
+	} else {
+		pr_warn("Concurrent rmmod and shutdown illegal!\n");
+	}
+	mutex_unlock(&fullstop_mutex);
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block torture_shutdown_nb = {
+	.notifier_call = torture_shutdown_notify,
+};
+
+/*
+ * Shut down the shutdown task.  Say what???  Heh!  This can happen if
+ * the torture module gets an rmmod before the shutdown time arrives.  ;-)
+ */
+static void torture_shutdown_cleanup(void)
+{
+	unregister_reboot_notifier(&torture_shutdown_nb);
+	if (shutdown_task != NULL) {
+		VERBOSE_TOROUT_STRING("Stopping torture_shutdown task");
+		kthread_stop(shutdown_task);
+	}
+	shutdown_task = NULL;
+}
+
+/*
+ * Variables for stuttering, which means to periodically pause and
+ * restart testing in order to catch bugs that appear when load is
+ * suddenly applied to or removed from the system.
+ */
+static struct task_struct *stutter_task;
+static int stutter_pause_test;
+static int stutter;
+
+/*
+ * Block until the stutter interval ends.  This must be called periodically
+ * by all running kthreads that need to be subject to stuttering.
+ */
+void stutter_wait(const char *title)
+{
+	while (ACCESS_ONCE(stutter_pause_test) ||
+	       (torture_runnable && !ACCESS_ONCE(*torture_runnable))) {
+		if (stutter_pause_test)
+			schedule_timeout_interruptible(1);
+		else
+			schedule_timeout_interruptible(round_jiffies_relative(HZ));
+		torture_shutdown_absorb(title);
+	}
+}
+EXPORT_SYMBOL_GPL(stutter_wait);
+
+/*
+ * Cause the torture test to "stutter", starting and stopping all
+ * threads periodically.
+ */
+static int torture_stutter(void *arg)
+{
+	VERBOSE_TOROUT_STRING("torture_stutter task started");
+	do {
+		if (!torture_must_stop()) {
+			schedule_timeout_interruptible(stutter);
+			ACCESS_ONCE(stutter_pause_test) = 1;
+		}
+		if (!torture_must_stop())
+			schedule_timeout_interruptible(stutter);
+		ACCESS_ONCE(stutter_pause_test) = 0;
+		torture_shutdown_absorb("torture_stutter");
+	} while (!torture_must_stop());
+	torture_kthread_stopping("torture_stutter");
+	return 0;
+}
+
+/*
+ * Initialize and kick off the torture_stutter kthread.
+ */
+int torture_stutter_init(int s)
+{
+	int ret;
+
+	stutter = s;
+	ret = torture_create_kthread(torture_stutter, NULL, stutter_task);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(torture_stutter_init);
+
+/*
+ * Cleanup after the torture_stutter kthread.
+ */
+static void torture_stutter_cleanup(void)
+{
+	if (!stutter_task)
+		return;
+	VERBOSE_TOROUT_STRING("Stopping torture_stutter task");
+	kthread_stop(stutter_task);
+	stutter_task = NULL;
+}
+
+/*
+ * Initialize torture module.  Please note that this is -not- invoked via
+ * the usual module_init() mechanism, but rather by an explicit call from
+ * the client torture module.  This call must be paired with a later
+ * torture_init_end().
+ *
+ * The runnable parameter points to a flag that controls whether or not
+ * the test is currently runnable.  If there is no such flag, pass in NULL.
+ */
+void __init torture_init_begin(char *ttype, bool v, int *runnable)
+{
+	mutex_lock(&fullstop_mutex);
+	torture_type = ttype;
+	verbose = v;
+	torture_runnable = runnable;
+	fullstop = FULLSTOP_DONTSTOP;
+
+}
+EXPORT_SYMBOL_GPL(torture_init_begin);
+
+/*
+ * Tell the torture module that initialization is complete.
+ */
+void __init torture_init_end(void)
+{
+	mutex_unlock(&fullstop_mutex);
+	register_reboot_notifier(&torture_shutdown_nb);
+}
+EXPORT_SYMBOL_GPL(torture_init_end);
+
+/*
+ * Clean up torture module.  Please note that this is -not- invoked via
+ * the usual module_exit() mechanism, but rather by an explicit call from
+ * the client torture module.  Returns true if a race with system shutdown
+ * is detected, otherwise, all kthreads started by functions in this file
+ * will be shut down.
+ *
+ * This must be called before the caller starts shutting down its own
+ * kthreads.
+ */
+bool torture_cleanup(void)
+{
+	mutex_lock(&fullstop_mutex);
+	if (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
+		pr_warn("Concurrent rmmod and shutdown illegal!\n");
+		mutex_unlock(&fullstop_mutex);
+		schedule_timeout_uninterruptible(10);
+		return true;
+	}
+	ACCESS_ONCE(fullstop) = FULLSTOP_RMMOD;
+	mutex_unlock(&fullstop_mutex);
+	torture_shutdown_cleanup();
+	torture_shuffle_cleanup();
+	torture_stutter_cleanup();
+	torture_onoff_cleanup();
+	return false;
+}
+EXPORT_SYMBOL_GPL(torture_cleanup);
+
+/*
+ * Is it time for the current torture test to stop?
+ */
+bool torture_must_stop(void)
+{
+	return torture_must_stop_irq() || kthread_should_stop();
+}
+EXPORT_SYMBOL_GPL(torture_must_stop);
+
+/*
+ * Is it time for the current torture test to stop?  This is the irq-safe
+ * version, hence no check for kthread_should_stop().
+ */
+bool torture_must_stop_irq(void)
+{
+	return ACCESS_ONCE(fullstop) != FULLSTOP_DONTSTOP;
+}
+EXPORT_SYMBOL_GPL(torture_must_stop_irq);
+
+/*
+ * Each kthread must wait for kthread_should_stop() before returning from
+ * its top-level function, otherwise segfaults ensue.  This function
+ * prints a "stopping" message and waits for kthread_should_stop(), and
+ * should be called from all torture kthreads immediately prior to
+ * returning.
+ */
+void torture_kthread_stopping(char *title)
+{
+	if (verbose)
+		VERBOSE_TOROUT_STRING(title);
+	while (!kthread_should_stop()) {
+		torture_shutdown_absorb(title);
+		schedule_timeout_uninterruptible(1);
+	}
+}
+EXPORT_SYMBOL_GPL(torture_kthread_stopping);
+
+/*
+ * Create a generic torture kthread that is immediately runnable.  If you
+ * need the kthread to be stopped so that you can do something to it before
+ * it starts, you will need to open-code your own.
+ */
+int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
+			    char *f, struct task_struct **tp)
+{
+	int ret = 0;
+
+	VERBOSE_TOROUT_STRING(m);
+	*tp = kthread_run(fn, arg, s);
+	if (IS_ERR(*tp)) {
+		ret = PTR_ERR(*tp);
+		VERBOSE_TOROUT_ERRSTRING(f);
+		*tp = NULL;
+	}
+	torture_shuffle_task_register(*tp);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(_torture_create_kthread);
+
+/*
+ * Stop a generic kthread, emitting a message.
+ */
+void _torture_stop_kthread(char *m, struct task_struct **tp)
+{
+	if (*tp == NULL)
+		return;
+	VERBOSE_TOROUT_STRING(m);
+	kthread_stop(*tp);
+	*tp = NULL;
+}
+EXPORT_SYMBOL_GPL(_torture_stop_kthread);