Merge commit 'v2.6.30-rc1' into x86/urgent

Merge reason: fix to be queued up depends on upstream facilities

Signed-off-by: Ingo Molnar <mingo@elte.hu>

18 files changed, 729 insertions, 221 deletions

diff --git a/kernel/Makefile b/kernel/Makefile
index bab1dffe37e..42423665660 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -74,6 +74,7 @@ obj-$(CONFIG_AUDIT_TREE) += audit_tree.o
 obj-$(CONFIG_KPROBES) += kprobes.o
 obj-$(CONFIG_KGDB) += kgdb.o
 obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o
+obj-$(CONFIG_DETECT_HUNG_TASK) += hung_task.o
 obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
 obj-$(CONFIG_SECCOMP) += seccomp.o
 obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o
diff --git a/kernel/exit.c b/kernel/exit.c
index 32cbf2607cb..abf9cf3b95c 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -923,6 +923,8 @@ NORET_TYPE void do_exit(long code)
 		schedule();
 	}
 
+	exit_irq_thread();
+
 	exit_signals(tsk);  /* sets PF_EXITING */
 	/*
 	 * tsk->flags are checked in the futex code to protect against
diff --git a/kernel/fork.c b/kernel/fork.c
index 660c2b8765b..989c7c202b3 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -645,6 +645,9 @@ static int copy_mm(unsigned long clone_flags, struct task_struct * tsk)
 
 	tsk->min_flt = tsk->maj_flt = 0;
 	tsk->nvcsw = tsk->nivcsw = 0;
+#ifdef CONFIG_DETECT_HUNG_TASK
+	tsk->last_switch_count = tsk->nvcsw + tsk->nivcsw;
+#endif
 
 	tsk->mm = NULL;
 	tsk->active_mm = NULL;
@@ -1032,11 +1035,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 
 	p->default_timer_slack_ns = current->timer_slack_ns;
 
-#ifdef CONFIG_DETECT_SOFTLOCKUP
-	p->last_switch_count = 0;
-	p->last_switch_timestamp = 0;
-#endif
-
 	task_io_accounting_init(&p->ioac);
 	acct_clear_integrals(p);
 
diff --git a/kernel/hung_task.c b/kernel/hung_task.c
new file mode 100644
index 00000000000..022a4927b78
--- /dev/null
+++ b/kernel/hung_task.c
@@ -0,0 +1,217 @@
+/*
+ * Detect Hung Task
+ *
+ * kernel/hung_task.c - kernel thread for detecting tasks stuck in D state
+ *
+ */
+
+#include <linux/mm.h>
+#include <linux/cpu.h>
+#include <linux/nmi.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/freezer.h>
+#include <linux/kthread.h>
+#include <linux/lockdep.h>
+#include <linux/module.h>
+#include <linux/sysctl.h>
+
+/*
+ * The number of tasks checked:
+ */
+unsigned long __read_mostly sysctl_hung_task_check_count = PID_MAX_LIMIT;
+
+/*
+ * Limit number of tasks checked in a batch.
+ *
+ * This value controls the preemptibility of khungtaskd since preemption
+ * is disabled during the critical section. It also controls the size of
+ * the RCU grace period. So it needs to be upper-bound.
+ */
+#define HUNG_TASK_BATCHING 1024
+
+/*
+ * Zero means infinite timeout - no checking done:
+ */
+unsigned long __read_mostly sysctl_hung_task_timeout_secs = 120;
+
+unsigned long __read_mostly sysctl_hung_task_warnings = 10;
+
+static int __read_mostly did_panic;
+
+static struct task_struct *watchdog_task;
+
+/*
+ * Should we panic (and reboot, if panic_timeout= is set) when a
+ * hung task is detected:
+ */
+unsigned int __read_mostly sysctl_hung_task_panic =
+				CONFIG_BOOTPARAM_HUNG_TASK_PANIC_VALUE;
+
+static int __init hung_task_panic_setup(char *str)
+{
+	sysctl_hung_task_panic = simple_strtoul(str, NULL, 0);
+
+	return 1;
+}
+__setup("hung_task_panic=", hung_task_panic_setup);
+
+static int
+hung_task_panic(struct notifier_block *this, unsigned long event, void *ptr)
+{
+	did_panic = 1;
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block panic_block = {
+	.notifier_call = hung_task_panic,
+};
+
+static void check_hung_task(struct task_struct *t, unsigned long timeout)
+{
+	unsigned long switch_count = t->nvcsw + t->nivcsw;
+
+	/*
+	 * Ensure the task is not frozen.
+	 * Also, when a freshly created task is scheduled once, changes
+	 * its state to TASK_UNINTERRUPTIBLE without having ever been
+	 * switched out once, it musn't be checked.
+	 */
+	if (unlikely(t->flags & PF_FROZEN || !switch_count))
+		return;
+
+	if (switch_count != t->last_switch_count) {
+		t->last_switch_count = switch_count;
+		return;
+	}
+	if (!sysctl_hung_task_warnings)
+		return;
+	sysctl_hung_task_warnings--;
+
+	/*
+	 * Ok, the task did not get scheduled for more than 2 minutes,
+	 * complain:
+	 */
+	printk(KERN_ERR "INFO: task %s:%d blocked for more than "
+			"%ld seconds.\n", t->comm, t->pid, timeout);
+	printk(KERN_ERR "\"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\""
+			" disables this message.\n");
+	sched_show_task(t);
+	__debug_show_held_locks(t);
+
+	touch_nmi_watchdog();
+
+	if (sysctl_hung_task_panic)
+		panic("hung_task: blocked tasks");
+}
+
+/*
+ * To avoid extending the RCU grace period for an unbounded amount of time,
+ * periodically exit the critical section and enter a new one.
+ *
+ * For preemptible RCU it is sufficient to call rcu_read_unlock in order
+ * exit the grace period. For classic RCU, a reschedule is required.
+ */
+static void rcu_lock_break(struct task_struct *g, struct task_struct *t)
+{
+	get_task_struct(g);
+	get_task_struct(t);
+	rcu_read_unlock();
+	cond_resched();
+	rcu_read_lock();
+	put_task_struct(t);
+	put_task_struct(g);
+}
+
+/*
+ * Check whether a TASK_UNINTERRUPTIBLE does not get woken up for
+ * a really long time (120 seconds). If that happens, print out
+ * a warning.
+ */
+static void check_hung_uninterruptible_tasks(unsigned long timeout)
+{
+	int max_count = sysctl_hung_task_check_count;
+	int batch_count = HUNG_TASK_BATCHING;
+	struct task_struct *g, *t;
+
+	/*
+	 * If the system crashed already then all bets are off,
+	 * do not report extra hung tasks:
+	 */
+	if (test_taint(TAINT_DIE) || did_panic)
+		return;
+
+	rcu_read_lock();
+	do_each_thread(g, t) {
+		if (!--max_count)
+			goto unlock;
+		if (!--batch_count) {
+			batch_count = HUNG_TASK_BATCHING;
+			rcu_lock_break(g, t);
+			/* Exit if t or g was unhashed during refresh. */
+			if (t->state == TASK_DEAD || g->state == TASK_DEAD)
+				goto unlock;
+		}
+		/* use "==" to skip the TASK_KILLABLE tasks waiting on NFS */
+		if (t->state == TASK_UNINTERRUPTIBLE)
+			check_hung_task(t, timeout);
+	} while_each_thread(g, t);
+ unlock:
+	rcu_read_unlock();
+}
+
+static unsigned long timeout_jiffies(unsigned long timeout)
+{
+	/* timeout of 0 will disable the watchdog */
+	return timeout ? timeout * HZ : MAX_SCHEDULE_TIMEOUT;
+}
+
+/*
+ * Process updating of timeout sysctl
+ */
+int proc_dohung_task_timeout_secs(struct ctl_table *table, int write,
+				  struct file *filp, void __user *buffer,
+				  size_t *lenp, loff_t *ppos)
+{
+	int ret;
+
+	ret = proc_doulongvec_minmax(table, write, filp, buffer, lenp, ppos);
+
+	if (ret || !write)
+		goto out;
+
+	wake_up_process(watchdog_task);
+
+ out:
+	return ret;
+}
+
+/*
+ * kthread which checks for tasks stuck in D state
+ */
+static int watchdog(void *dummy)
+{
+	set_user_nice(current, 0);
+
+	for ( ; ; ) {
+		unsigned long timeout = sysctl_hung_task_timeout_secs;
+
+		while (schedule_timeout_interruptible(timeout_jiffies(timeout)))
+			timeout = sysctl_hung_task_timeout_secs;
+
+		check_hung_uninterruptible_tasks(timeout);
+	}
+
+	return 0;
+}
+
+static int __init hung_task_init(void)
+{
+	atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
+	watchdog_task = kthread_run(watchdog, NULL, "khungtaskd");
+
+	return 0;
+}
+
+module_init(hung_task_init);
diff --git a/kernel/irq/devres.c b/kernel/irq/devres.c
index 38a25b8d8bf..d06df9c41cb 100644
--- a/kernel/irq/devres.c
+++ b/kernel/irq/devres.c
@@ -26,10 +26,12 @@ static int devm_irq_match(struct device *dev, void *res, void *data)
 }
 
 /**
- *	devm_request_irq - allocate an interrupt line for a managed device
+ *	devm_request_threaded_irq - allocate an interrupt line for a managed device
  *	@dev: device to request interrupt for
  *	@irq: Interrupt line to allocate
  *	@handler: Function to be called when the IRQ occurs
+ *	@thread_fn: function to be called in a threaded interrupt context. NULL
+ *		    for devices which handle everything in @handler
  *	@irqflags: Interrupt type flags
  *	@devname: An ascii name for the claiming device
  *	@dev_id: A cookie passed back to the handler function
@@ -42,9 +44,10 @@ static int devm_irq_match(struct device *dev, void *res, void *data)
  *	If an IRQ allocated with this function needs to be freed
  *	separately, dev_free_irq() must be used.
  */
-int devm_request_irq(struct device *dev, unsigned int irq,
-		     irq_handler_t handler, unsigned long irqflags,
-		     const char *devname, void *dev_id)
+int devm_request_threaded_irq(struct device *dev, unsigned int irq,
+			      irq_handler_t handler, irq_handler_t thread_fn,
+			      unsigned long irqflags, const char *devname,
+			      void *dev_id)
 {
 	struct irq_devres *dr;
 	int rc;
@@ -54,7 +57,8 @@ int devm_request_irq(struct device *dev, unsigned int irq,
 	if (!dr)
 		return -ENOMEM;
 
-	rc = request_irq(irq, handler, irqflags, devname, dev_id);
+	rc = request_threaded_irq(irq, handler, thread_fn, irqflags, devname,
+				  dev_id);
 	if (rc) {
 		devres_free(dr);
 		return rc;
@@ -66,7 +70,7 @@ int devm_request_irq(struct device *dev, unsigned int irq,
 
 	return 0;
 }
-EXPORT_SYMBOL(devm_request_irq);
+EXPORT_SYMBOL(devm_request_threaded_irq);
 
 /**
  *	devm_free_irq - free an interrupt
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index 343acecae62..d82142be8dd 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -339,6 +339,15 @@ irqreturn_t no_action(int cpl, void *dev_id)
 	return IRQ_NONE;
 }
 
+static void warn_no_thread(unsigned int irq, struct irqaction *action)
+{
+	if (test_and_set_bit(IRQTF_WARNED, &action->thread_flags))
+		return;
+
+	printk(KERN_WARNING "IRQ %d device %s returned IRQ_WAKE_THREAD "
+	       "but no thread function available.", irq, action->name);
+}
+
 DEFINE_TRACE(irq_handler_entry);
 DEFINE_TRACE(irq_handler_exit);
 
@@ -363,8 +372,47 @@ irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
 		trace_irq_handler_entry(irq, action);
 		ret = action->handler(irq, action->dev_id);
 		trace_irq_handler_exit(irq, action, ret);
-		if (ret == IRQ_HANDLED)
+
+		switch (ret) {
+		case IRQ_WAKE_THREAD:
+			/*
+			 * Set result to handled so the spurious check
+			 * does not trigger.
+			 */
+			ret = IRQ_HANDLED;
+
+			/*
+			 * Catch drivers which return WAKE_THREAD but
+			 * did not set up a thread function
+			 */
+			if (unlikely(!action->thread_fn)) {
+				warn_no_thread(irq, action);
+				break;
+			}
+
+			/*
+			 * Wake up the handler thread for this
+			 * action. In case the thread crashed and was
+			 * killed we just pretend that we handled the
+			 * interrupt. The hardirq handler above has
+			 * disabled the device interrupt, so no irq
+			 * storm is lurking.
+			 */
+			if (likely(!test_bit(IRQTF_DIED,
+					     &action->thread_flags))) {
+				set_bit(IRQTF_RUNTHREAD, &action->thread_flags);
+				wake_up_process(action->thread);
+			}
+
+			/* Fall through to add to randomness */
+		case IRQ_HANDLED:
 			status |= action->flags;
+			break;
+
+		default:
+			break;
+		}
+
 		retval |= ret;
 		action = action->next;
 	} while (action);
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 1516ab77355..7e2e7dd4cd2 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -8,16 +8,15 @@
  */
 
 #include <linux/irq.h>
+#include <linux/kthread.h>
 #include <linux/module.h>
 #include <linux/random.h>
 #include <linux/interrupt.h>
 #include <linux/slab.h>
+#include <linux/sched.h>
 
 #include "internals.h"
 
-#if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_HARDIRQS)
-cpumask_var_t irq_default_affinity;
-
 /**
  *	synchronize_irq - wait for pending IRQ handlers (on other CPUs)
  *	@irq: interrupt number to wait for
@@ -53,9 +52,18 @@ void synchronize_irq(unsigned int irq)
 
 		/* Oops, that failed? */
 	} while (status & IRQ_INPROGRESS);
+
+	/*
+	 * We made sure that no hardirq handler is running. Now verify
+	 * that no threaded handlers are active.
+	 */
+	wait_event(desc->wait_for_threads, !atomic_read(&desc->threads_active));
 }
 EXPORT_SYMBOL(synchronize_irq);
 
+#ifdef CONFIG_SMP
+cpumask_var_t irq_default_affinity;
+
 /**
  *	irq_can_set_affinity - Check if the affinity of a given irq can be set
  *	@irq:		Interrupt to check
@@ -72,6 +80,18 @@ int irq_can_set_affinity(unsigned int irq)
 	return 1;
 }
 
+static void
+irq_set_thread_affinity(struct irq_desc *desc, const struct cpumask *cpumask)
+{
+	struct irqaction *action = desc->action;
+
+	while (action) {
+		if (action->thread)
+			set_cpus_allowed_ptr(action->thread, cpumask);
+		action = action->next;
+	}
+}
+
 /**
  *	irq_set_affinity - Set the irq affinity of a given irq
  *	@irq:		Interrupt to set affinity
@@ -100,6 +120,7 @@ int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask)
 	cpumask_copy(desc->affinity, cpumask);
 	desc->chip->set_affinity(irq, cpumask);
 #endif
+	irq_set_thread_affinity(desc, cpumask);
 	desc->status |= IRQ_AFFINITY_SET;
 	spin_unlock_irqrestore(&desc->lock, flags);
 	return 0;
@@ -150,6 +171,8 @@ int irq_select_affinity_usr(unsigned int irq)
 
 	spin_lock_irqsave(&desc->lock, flags);
 	ret = setup_affinity(irq, desc);
+	if (!ret)
+		irq_set_thread_affinity(desc, desc->affinity);
 	spin_unlock_irqrestore(&desc->lock, flags);
 
 	return ret;
@@ -401,6 +424,90 @@ int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
 	return ret;
 }
 
+static int irq_wait_for_interrupt(struct irqaction *action)
+{
+	while (!kthread_should_stop()) {
+		set_current_state(TASK_INTERRUPTIBLE);
+
+		if (test_and_clear_bit(IRQTF_RUNTHREAD,
+				       &action->thread_flags)) {
+			__set_current_state(TASK_RUNNING);
+			return 0;
+		}
+		schedule();
+	}
+	return -1;
+}
+
+/*
+ * Interrupt handler thread
+ */
+static int irq_thread(void *data)
+{
+	struct sched_param param = { .sched_priority = MAX_USER_RT_PRIO/2, };
+	struct irqaction *action = data;
+	struct irq_desc *desc = irq_to_desc(action->irq);
+	int wake;
+
+	sched_setscheduler(current, SCHED_FIFO, &param);
+	current->irqaction = action;
+
+	while (!irq_wait_for_interrupt(action)) {
+
+		atomic_inc(&desc->threads_active);
+
+		spin_lock_irq(&desc->lock);
+		if (unlikely(desc->status & IRQ_DISABLED)) {
+			/*
+			 * CHECKME: We might need a dedicated
+			 * IRQ_THREAD_PENDING flag here, which
+			 * retriggers the thread in check_irq_resend()
+			 * but AFAICT IRQ_PENDING should be fine as it
+			 * retriggers the interrupt itself --- tglx
+			 */
+			desc->status |= IRQ_PENDING;
+			spin_unlock_irq(&desc->lock);
+		} else {
+			spin_unlock_irq(&desc->lock);
+
+			action->thread_fn(action->irq, action->dev_id);
+		}
+
+		wake = atomic_dec_and_test(&desc->threads_active);
+
+		if (wake && waitqueue_active(&desc->wait_for_threads))
+			wake_up(&desc->wait_for_threads);
+	}
+
+	/*
+	 * Clear irqaction. Otherwise exit_irq_thread() would make
+	 * fuzz about an active irq thread going into nirvana.
+	 */
+	current->irqaction = NULL;
+	return 0;
+}
+
+/*
+ * Called from do_exit()
+ */
+void exit_irq_thread(void)
+{
+	struct task_struct *tsk = current;
+
+	if (!tsk->irqaction)
+		return;
+
+	printk(KERN_ERR
+	       "exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
+	       tsk->comm ? tsk->comm : "", tsk->pid, tsk->irqaction->irq);
+
+	/*
+	 * Set the THREAD DIED flag to prevent further wakeups of the
+	 * soon to be gone threaded handler.
+	 */
+	set_bit(IRQTF_DIED, &tsk->irqaction->flags);
+}
+
 /*
  * Internal function to register an irqaction - typically used to
  * allocate special interrupts that are part of the architecture.
@@ -437,6 +544,26 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 	}
 
 	/*
+	 * Threaded handler ?
+	 */
+	if (new->thread_fn) {
+		struct task_struct *t;
+
+		t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
+				   new->name);
+		if (IS_ERR(t))
+			return PTR_ERR(t);
+		/*
+		 * We keep the reference to the task struct even if
+		 * the thread dies to avoid that the interrupt code
+		 * references an already freed task_struct.
+		 */
+		get_task_struct(t);
+		new->thread = t;
+		wake_up_process(t);
+	}
+
+	/*
 	 * The following block of code has to be executed atomically
 	 */
 	spin_lock_irqsave(&desc->lock, flags);
@@ -473,15 +600,15 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 	if (!shared) {
 		irq_chip_set_defaults(desc->chip);
 
+		init_waitqueue_head(&desc->wait_for_threads);
+
 		/* Setup the type (level, edge polarity) if configured: */
 		if (new->flags & IRQF_TRIGGER_MASK) {
 			ret = __irq_set_trigger(desc, irq,
 					new->flags & IRQF_TRIGGER_MASK);
 
-			if (ret) {
-				spin_unlock_irqrestore(&desc->lock, flags);
-				return ret;
-			}
+			if (ret)
+				goto out_thread;
 		} else
 			compat_irq_chip_set_default_handler(desc);
 #if defined(CONFIG_IRQ_PER_CPU)
@@ -549,8 +676,19 @@ mismatch:
 		dump_stack();
 	}
 #endif
+	ret = -EBUSY;
+
+out_thread:
 	spin_unlock_irqrestore(&desc->lock, flags);
-	return -EBUSY;
+	if (new->thread) {
+		struct task_struct *t = new->thread;
+
+		new->thread = NULL;
+		if (likely(!test_bit(IRQTF_DIED, &new->thread_flags)))
+			kthread_stop(t);
+		put_task_struct(t);
+	}
+	return ret;
 }
 
 /**
@@ -576,6 +714,7 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
 {
 	struct irq_desc *desc = irq_to_desc(irq);
 	struct irqaction *action, **action_ptr;
+	struct task_struct *irqthread;
 	unsigned long flags;
 
 	WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
@@ -622,6 +761,10 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
 		else
 			desc->chip->disable(irq);
 	}
+
+	irqthread = action->thread;
+	action->thread = NULL;
+
 	spin_unlock_irqrestore(&desc->lock, flags);
 
 	unregister_handler_proc(irq, action);
@@ -629,6 +772,12 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
 	/* Make sure it's not being used on another CPU: */
 	synchronize_irq(irq);
 
+	if (irqthread) {
+		if (!test_bit(IRQTF_DIED, &action->thread_flags))
+			kthread_stop(irqthread);
+		put_task_struct(irqthread);
+	}
+
 #ifdef CONFIG_DEBUG_SHIRQ
 	/*
 	 * It's a shared IRQ -- the driver ought to be prepared for an IRQ
@@ -681,9 +830,12 @@ void free_irq(unsigned int irq, void *dev_id)
 EXPORT_SYMBOL(free_irq);
 
 /**
- *	request_irq - allocate an interrupt line
+ *	request_threaded_irq - allocate an interrupt line
  *	@irq: Interrupt line to allocate
- *	@handler: Function to be called when the IRQ occurs
+ *	@handler: Function to be called when the IRQ occurs.
+ *		  Primary handler for threaded interrupts
+ *	@thread_fn: Function called from the irq handler thread
+ *		    If NULL, no irq thread is created
  *	@irqflags: Interrupt type flags
  *	@devname: An ascii name for the claiming device
  *	@dev_id: A cookie passed back to the handler function
@@ -695,6 +847,15 @@ EXPORT_SYMBOL(free_irq);
  *	raises, you must take care both to initialise your hardware
  *	and to set up the interrupt handler in the right order.
  *
+ *	If you want to set up a threaded irq handler for your device
+ *	then you need to supply @handler and @thread_fn. @handler ist
+ *	still called in hard interrupt context and has to check
+ *	whether the interrupt originates from the device. If yes it
+ *	needs to disable the interrupt on the device and return
+ *	IRQ_THREAD_WAKE which will wake up the handler thread and run
+ *	@thread_fn. This split handler design is necessary to support
+ *	shared interrupts.
+ *
  *	Dev_id must be globally unique. Normally the address of the
  *	device data structure is used as the cookie. Since the handler
  *	receives this value it makes sense to use it.
@@ -710,8 +871,9 @@ EXPORT_SYMBOL(free_irq);
  *	IRQF_TRIGGER_*		Specify active edge(s) or level
  *
  */
-int request_irq(unsigned int irq, irq_handler_t handler,
-		unsigned long irqflags, const char *devname, void *dev_id)
+int request_threaded_irq(unsigned int irq, irq_handler_t handler,
+			 irq_handler_t thread_fn, unsigned long irqflags,
+			 const char *devname, void *dev_id)
 {
 	struct irqaction *action;
 	struct irq_desc *desc;
@@ -759,6 +921,7 @@ int request_irq(unsigned int irq, irq_handler_t handler,
 		return -ENOMEM;
 
 	action->handler = handler;
+	action->thread_fn = thread_fn;
 	action->flags = irqflags;
 	action->name = devname;
 	action->dev_id = dev_id;
@@ -788,4 +951,4 @@ int request_irq(unsigned int irq, irq_handler_t handler,
 #endif
 	return retval;
 }
-EXPORT_SYMBOL(request_irq);
+EXPORT_SYMBOL(request_threaded_irq);
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 5016bfb682b..a5e74ddee0e 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -68,7 +68,7 @@ static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
 static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
 
 /* NOTE: change this value only with kprobe_mutex held */
-static bool kprobe_enabled;
+static bool kprobes_all_disarmed;
 
 static DEFINE_MUTEX(kprobe_mutex);	/* Protects kprobe_table */
 static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
@@ -328,7 +328,7 @@ static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
 	struct kprobe *kp;
 
 	list_for_each_entry_rcu(kp, &p->list, list) {
-		if (kp->pre_handler && !kprobe_gone(kp)) {
+		if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
 			set_kprobe_instance(kp);
 			if (kp->pre_handler(kp, regs))
 				return 1;
@@ -344,7 +344,7 @@ static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
 	struct kprobe *kp;
 
 	list_for_each_entry_rcu(kp, &p->list, list) {
-		if (kp->post_handler && !kprobe_gone(kp)) {
+		if (kp->post_handler && likely(!kprobe_disabled(kp))) {
 			set_kprobe_instance(kp);
 			kp->post_handler(kp, regs, flags);
 			reset_kprobe_instance();
@@ -518,20 +518,28 @@ static inline void copy_kprobe(struct kprobe *old_p, struct kprobe *p)
 }
 
 /*
-* Add the new probe to old_p->list. Fail if this is the
+* Add the new probe to ap->list. Fail if this is the
 * second jprobe at the address - two jprobes can't coexist
 */
-static int __kprobes add_new_kprobe(struct kprobe *old_p, struct kprobe *p)
+static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p)
 {
+	BUG_ON(kprobe_gone(ap) || kprobe_gone(p));
 	if (p->break_handler) {
-		if (old_p->break_handler)
+		if (ap->break_handler)
 			return -EEXIST;
-		list_add_tail_rcu(&p->list, &old_p->list);
-		old_p->break_handler = aggr_break_handler;
+		list_add_tail_rcu(&p->list, &ap->list);
+		ap->break_handler = aggr_break_handler;
 	} else
-		list_add_rcu(&p->list, &old_p->list);
-	if (p->post_handler && !old_p->post_handler)
-		old_p->post_handler = aggr_post_handler;
+		list_add_rcu(&p->list, &ap->list);
+	if (p->post_handler && !ap->post_handler)
+		ap->post_handler = aggr_post_handler;
+
+	if (kprobe_disabled(ap) && !kprobe_disabled(p)) {
+		ap->flags &= ~KPROBE_FLAG_DISABLED;
+		if (!kprobes_all_disarmed)
+			/* Arm the breakpoint again. */
+			arch_arm_kprobe(ap);
+	}
 	return 0;
 }
 
@@ -544,6 +552,7 @@ static inline void add_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
 	copy_kprobe(p, ap);
 	flush_insn_slot(ap);
 	ap->addr = p->addr;
+	ap->flags = p->flags;
 	ap->pre_handler = aggr_pre_handler;
 	ap->fault_handler = aggr_fault_handler;
 	/* We don't care the kprobe which has gone. */
@@ -566,44 +575,59 @@ static int __kprobes register_aggr_kprobe(struct kprobe *old_p,
 					  struct kprobe *p)
 {
 	int ret = 0;
-	struct kprobe *ap;
+	struct kprobe *ap = old_p;
 
-	if (kprobe_gone(old_p)) {
+	if (old_p->pre_handler != aggr_pre_handler) {
+		/* If old_p is not an aggr_probe, create new aggr_kprobe. */
+		ap = kzalloc(sizeof(struct kprobe), GFP_KERNEL);
+		if (!ap)
+			return -ENOMEM;
+		add_aggr_kprobe(ap, old_p);
+	}
+
+	if (kprobe_gone(ap)) {
 		/*
 		 * Attempting to insert new probe at the same location that
 		 * had a probe in the module vaddr area which already
 		 * freed. So, the instruction slot has already been
 		 * released. We need a new slot for the new probe.
 		 */
-		ret = arch_prepare_kprobe(old_p);
+		ret = arch_prepare_kprobe(ap);
 		if (ret)
+			/*
+			 * Even if fail to allocate new slot, don't need to
+			 * free aggr_probe. It will be used next time, or
+			 * freed by unregister_kprobe.
+			 */
 			return ret;
-	}
-	if (old_p->pre_handler == aggr_pre_handler) {
-		copy_kprobe(old_p, p);
-		ret = add_new_kprobe(old_p, p);
-		ap = old_p;
-	} else {
-		ap = kzalloc(sizeof(struct kprobe), GFP_KERNEL);
-		if (!ap) {
-			if (kprobe_gone(old_p))
-				arch_remove_kprobe(old_p);
-			return -ENOMEM;
-		}
-		add_aggr_kprobe(ap, old_p);
-		copy_kprobe(ap, p);
-		ret = add_new_kprobe(ap, p);
-	}
-	if (kprobe_gone(old_p)) {
+
 		/*
-		 * If the old_p has gone, its breakpoint has been disarmed.
-		 * We have to arm it again after preparing real kprobes.
+		 * Clear gone flag to prevent allocating new slot again, and
+		 * set disabled flag because it is not armed yet.
 		 */
-		ap->flags &= ~KPROBE_FLAG_GONE;
-		if (kprobe_enabled)
-			arch_arm_kprobe(ap);
+		ap->flags = (ap->flags & ~KPROBE_FLAG_GONE)
+			    | KPROBE_FLAG_DISABLED;
 	}
-	return ret;
+
+	copy_kprobe(ap, p);
+	return add_new_kprobe(ap, p);
+}
+
+/* Try to disable aggr_kprobe, and return 1 if succeeded.*/
+static int __kprobes try_to_disable_aggr_kprobe(struct kprobe *p)
+{
+	struct kprobe *kp;
+
+	list_for_each_entry_rcu(kp, &p->list, list) {
+		if (!kprobe_disabled(kp))
+			/*
+			 * There is an active probe on the list.
+			 * We can't disable aggr_kprobe.
+			 */
+			return 0;
+	}
+	p->flags |= KPROBE_FLAG_DISABLED;
+	return 1;
 }
 
 static int __kprobes in_kprobes_functions(unsigned long addr)
@@ -664,7 +688,9 @@ int __kprobes register_kprobe(struct kprobe *p)
 		return -EINVAL;
 	}
 
-	p->flags = 0;
+	/* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
+	p->flags &= KPROBE_FLAG_DISABLED;
+
 	/*
 	 * Check if are we probing a module.
 	 */
@@ -709,7 +735,7 @@ int __kprobes register_kprobe(struct kprobe *p)
 	hlist_add_head_rcu(&p->hlist,
 		       &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
 
-	if (kprobe_enabled)
+	if (!kprobes_all_disarmed && !kprobe_disabled(p))
 		arch_arm_kprobe(p);
 
 out_unlock_text:
@@ -722,26 +748,39 @@ out:
 
 	return ret;
 }
+EXPORT_SYMBOL_GPL(register_kprobe);
 
-/*
- * Unregister a kprobe without a scheduler synchronization.
- */
-static int __kprobes __unregister_kprobe_top(struct kprobe *p)
+/* Check passed kprobe is valid and return kprobe in kprobe_table. */
+static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p)
 {
 	struct kprobe *old_p, *list_p;
 
 	old_p = get_kprobe(p->addr);
 	if (unlikely(!old_p))
-		return -EINVAL;
+		return NULL;
 
 	if (p != old_p) {
 		list_for_each_entry_rcu(list_p, &old_p->list, list)
 			if (list_p == p)
 			/* kprobe p is a valid probe */
-				goto valid_p;
-		return -EINVAL;
+				goto valid;
+		return NULL;
 	}
-valid_p:
+valid:
+	return old_p;
+}
+
+/*
+ * Unregister a kprobe without a scheduler synchronization.
+ */
+static int __kprobes __unregister_kprobe_top(struct kprobe *p)
+{
+	struct kprobe *old_p, *list_p;
+
+	old_p = __get_valid_kprobe(p);
+	if (old_p == NULL)
+		return -EINVAL;
+
 	if (old_p == p ||
 	    (old_p->pre_handler == aggr_pre_handler &&
 	     list_is_singular(&old_p->list))) {
@@ -750,7 +789,7 @@ valid_p:
 		 * enabled and not gone - otherwise, the breakpoint would
 		 * already have been removed. We save on flushing icache.
 		 */
-		if (kprobe_enabled && !kprobe_gone(old_p)) {
+		if (!kprobes_all_disarmed && !kprobe_disabled(old_p)) {
 			mutex_lock(&text_mutex);
 			arch_disarm_kprobe(p);
 			mutex_unlock(&text_mutex);
@@ -768,6 +807,11 @@ valid_p:
 		}
 noclean:
 		list_del_rcu(&p->list);
+		if (!kprobe_disabled(old_p)) {
+			try_to_disable_aggr_kprobe(old_p);
+			if (!kprobes_all_disarmed && kprobe_disabled(old_p))
+				arch_disarm_kprobe(old_p);
+		}
 	}
 	return 0;
 }
@@ -803,11 +847,13 @@ int __kprobes register_kprobes(struct kprobe **kps, int num)
 	}
 	return ret;
 }
+EXPORT_SYMBOL_GPL(register_kprobes);
 
 void __kprobes unregister_kprobe(struct kprobe *p)
 {
 	unregister_kprobes(&p, 1);
 }
+EXPORT_SYMBOL_GPL(unregister_kprobe);
 
 void __kprobes unregister_kprobes(struct kprobe **kps, int num)
 {
@@ -826,6 +872,7 @@ void __kprobes unregister_kprobes(struct kprobe **kps, int num)
 		if (kps[i]->addr)
 			__unregister_kprobe_bottom(kps[i]);
 }
+EXPORT_SYMBOL_GPL(unregister_kprobes);
 
 static struct notifier_block kprobe_exceptions_nb = {
 	.notifier_call = kprobe_exceptions_notify,
@@ -865,16 +912,19 @@ int __kprobes register_jprobes(struct jprobe **jps, int num)
 	}
 	return ret;
 }
+EXPORT_SYMBOL_GPL(register_jprobes);
 
 int __kprobes register_jprobe(struct jprobe *jp)
 {
 	return register_jprobes(&jp, 1);
 }
+EXPORT_SYMBOL_GPL(register_jprobe);
 
 void __kprobes unregister_jprobe(struct jprobe *jp)
 {
 	unregister_jprobes(&jp, 1);
 }
+EXPORT_SYMBOL_GPL(unregister_jprobe);
 
 void __kprobes unregister_jprobes(struct jprobe **jps, int num)
 {
@@ -894,6 +944,7 @@ void __kprobes unregister_jprobes(struct jprobe **jps, int num)
 			__unregister_kprobe_bottom(&jps[i]->kp);
 	}
 }
+EXPORT_SYMBOL_GPL(unregister_jprobes);
 
 #ifdef CONFIG_KRETPROBES
 /*
@@ -987,6 +1038,7 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
 		free_rp_inst(rp);
 	return ret;
 }
+EXPORT_SYMBOL_GPL(register_kretprobe);
 
 int __kprobes register_kretprobes(struct kretprobe **rps, int num)
 {
@@ -1004,11 +1056,13 @@ int __kprobes register_kretprobes(struct kretprobe **rps, int num)
 	}
 	return ret;
 }
+EXPORT_SYMBOL_GPL(register_kretprobes);
 
 void __kprobes unregister_kretprobe(struct kretprobe *rp)
 {
 	unregister_kretprobes(&rp, 1);
 }
+EXPORT_SYMBOL_GPL(unregister_kretprobe);
 
 void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
 {
@@ -1030,24 +1084,30 @@ void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
 		}
 	}
 }
+EXPORT_SYMBOL_GPL(unregister_kretprobes);
 
 #else /* CONFIG_KRETPROBES */
 int __kprobes register_kretprobe(struct kretprobe *rp)
 {
 	return -ENOSYS;
 }
+EXPORT_SYMBOL_GPL(register_kretprobe);
 
 int __kprobes register_kretprobes(struct kretprobe **rps, int num)
 {
 	return -ENOSYS;
 }
+EXPORT_SYMBOL_GPL(register_kretprobes);
+
 void __kprobes unregister_kretprobe(struct kretprobe *rp)
 {
 }
+EXPORT_SYMBOL_GPL(unregister_kretprobe);
 
 void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
 {
 }
+EXPORT_SYMBOL_GPL(unregister_kretprobes);
 
 static int __kprobes pre_handler_kretprobe(struct kprobe *p,
 					   struct pt_regs *regs)
@@ -1061,6 +1121,7 @@ static int __kprobes pre_handler_kretprobe(struct kprobe *p,
 static void __kprobes kill_kprobe(struct kprobe *p)
 {
 	struct kprobe *kp;
+
 	p->flags |= KPROBE_FLAG_GONE;
 	if (p->pre_handler == aggr_pre_handler) {
 		/*
@@ -1173,8 +1234,8 @@ static int __init init_kprobes(void)
 		}
 	}
 
-	/* By default, kprobes are enabled */
-	kprobe_enabled = true;
+	/* By default, kprobes are armed */
+	kprobes_all_disarmed = false;
 
 	err = arch_init_kprobes();
 	if (!err)
@@ -1202,12 +1263,18 @@ static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p,
 	else
 		kprobe_type = "k";
 	if (sym)
-		seq_printf(pi, "%p  %s  %s+0x%x  %s %s\n", p->addr, kprobe_type,
-			sym, offset, (modname ? modname : " "),
-			(kprobe_gone(p) ? "[GONE]" : ""));
+		seq_printf(pi, "%p  %s  %s+0x%x  %s %s%s\n",
+			p->addr, kprobe_type, sym, offset,
+			(modname ? modname : " "),
+			(kprobe_gone(p) ? "[GONE]" : ""),
+			((kprobe_disabled(p) && !kprobe_gone(p)) ?
+			 "[DISABLED]" : ""));
 	else
-		seq_printf(pi, "%p  %s  %p %s\n", p->addr, kprobe_type, p->addr,
-			(kprobe_gone(p) ? "[GONE]" : ""));
+		seq_printf(pi, "%p  %s  %p %s%s\n",
+			p->addr, kprobe_type, p->addr,
+			(kprobe_gone(p) ? "[GONE]" : ""),
+			((kprobe_disabled(p) && !kprobe_gone(p)) ?
+			 "[DISABLED]" : ""));
 }
 
 static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos)
@@ -1272,7 +1339,72 @@ static struct file_operations debugfs_kprobes_operations = {
 	.release        = seq_release,
 };
 
-static void __kprobes enable_all_kprobes(void)
+/* Disable one kprobe */
+int __kprobes disable_kprobe(struct kprobe *kp)
+{
+	int ret = 0;
+	struct kprobe *p;
+
+	mutex_lock(&kprobe_mutex);
+
+	/* Check whether specified probe is valid. */
+	p = __get_valid_kprobe(kp);
+	if (unlikely(p == NULL)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* If the probe is already disabled (or gone), just return */
+	if (kprobe_disabled(kp))
+		goto out;
+
+	kp->flags |= KPROBE_FLAG_DISABLED;
+	if (p != kp)
+		/* When kp != p, p is always enabled. */
+		try_to_disable_aggr_kprobe(p);
+
+	if (!kprobes_all_disarmed && kprobe_disabled(p))
+		arch_disarm_kprobe(p);
+out:
+	mutex_unlock(&kprobe_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(disable_kprobe);
+
+/* Enable one kprobe */
+int __kprobes enable_kprobe(struct kprobe *kp)
+{
+	int ret = 0;
+	struct kprobe *p;
+
+	mutex_lock(&kprobe_mutex);
+
+	/* Check whether specified probe is valid. */
+	p = __get_valid_kprobe(kp);
+	if (unlikely(p == NULL)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (kprobe_gone(kp)) {
+		/* This kprobe has gone, we couldn't enable it. */
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (!kprobes_all_disarmed && kprobe_disabled(p))
+		arch_arm_kprobe(p);
+
+	p->flags &= ~KPROBE_FLAG_DISABLED;
+	if (p != kp)
+		kp->flags &= ~KPROBE_FLAG_DISABLED;
+out:
+	mutex_unlock(&kprobe_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(enable_kprobe);
+
+static void __kprobes arm_all_kprobes(void)
 {
 	struct hlist_head *head;
 	struct hlist_node *node;
@@ -1281,20 +1413,20 @@ static void __kprobes enable_all_kprobes(void)
 
 	mutex_lock(&kprobe_mutex);
 
-	/* If kprobes are already enabled, just return */
-	if (kprobe_enabled)
+	/* If kprobes are armed, just return */
+	if (!kprobes_all_disarmed)
 		goto already_enabled;
 
 	mutex_lock(&text_mutex);
 	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
 		head = &kprobe_table[i];
 		hlist_for_each_entry_rcu(p, node, head, hlist)
-			if (!kprobe_gone(p))
+			if (!kprobe_disabled(p))
 				arch_arm_kprobe(p);
 	}
 	mutex_unlock(&text_mutex);
 
-	kprobe_enabled = true;
+	kprobes_all_disarmed = false;
 	printk(KERN_INFO "Kprobes globally enabled\n");
 
 already_enabled:
@@ -1302,7 +1434,7 @@ already_enabled:
 	return;
 }
 
-static void __kprobes disable_all_kprobes(void)
+static void __kprobes disarm_all_kprobes(void)
 {
 	struct hlist_head *head;
 	struct hlist_node *node;
@@ -1311,17 +1443,17 @@ static void __kprobes disable_all_kprobes(void)
 
 	mutex_lock(&kprobe_mutex);
 
-	/* If kprobes are already disabled, just return */
-	if (!kprobe_enabled)
+	/* If kprobes are already disarmed, just return */
+	if (kprobes_all_disarmed)
 		goto already_disabled;
 
-	kprobe_enabled = false;
+	kprobes_all_disarmed = true;
 	printk(KERN_INFO "Kprobes globally disabled\n");
 	mutex_lock(&text_mutex);
 	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
 		head = &kprobe_table[i];
 		hlist_for_each_entry_rcu(p, node, head, hlist) {
-			if (!arch_trampoline_kprobe(p) && !kprobe_gone(p))
+			if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p))
 				arch_disarm_kprobe(p);
 		}
 	}
@@ -1347,7 +1479,7 @@ static ssize_t read_enabled_file_bool(struct file *file,
 {
 	char buf[3];
 
-	if (kprobe_enabled)
+	if (!kprobes_all_disarmed)
 		buf[0] = '1';
 	else
 		buf[0] = '0';
@@ -1370,12 +1502,12 @@ static ssize_t write_enabled_file_bool(struct file *file,
 	case 'y':
 	case 'Y':
 	case '1':
-		enable_all_kprobes();
+		arm_all_kprobes();
 		break;
 	case 'n':
 	case 'N':
 	case '0':
-		disable_all_kprobes();
+		disarm_all_kprobes();
 		break;
 	}
 
@@ -1418,16 +1550,5 @@ late_initcall(debugfs_kprobe_init);
 
 module_init(init_kprobes);
 
-EXPORT_SYMBOL_GPL(register_kprobe);
-EXPORT_SYMBOL_GPL(unregister_kprobe);
-EXPORT_SYMBOL_GPL(register_kprobes);
-EXPORT_SYMBOL_GPL(unregister_kprobes);
-EXPORT_SYMBOL_GPL(register_jprobe);
-EXPORT_SYMBOL_GPL(unregister_jprobe);
-EXPORT_SYMBOL_GPL(register_jprobes);
-EXPORT_SYMBOL_GPL(unregister_jprobes);
+/* defined in arch/.../kernel/kprobes.c */
 EXPORT_SYMBOL_GPL(jprobe_return);
-EXPORT_SYMBOL_GPL(register_kretprobe);
-EXPORT_SYMBOL_GPL(unregister_kretprobe);
-EXPORT_SYMBOL_GPL(register_kretprobes);
-EXPORT_SYMBOL_GPL(unregister_kretprobes);
diff --git a/kernel/module.c b/kernel/module.c
index c268a771595..05f014efa32 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1952,9 +1952,6 @@ static noinline struct module *load_module(void __user *umod,
 		if (strstarts(secstrings+sechdrs[i].sh_name, ".exit"))
 			sechdrs[i].sh_flags &= ~(unsigned long)SHF_ALLOC;
 #endif
-		/* Don't keep __versions around; it's just for loading. */
-		if (strcmp(secstrings + sechdrs[i].sh_name, "__versions") == 0)
-			sechdrs[i].sh_flags &= ~(unsigned long)SHF_ALLOC;
 	}
 
 	modindex = find_sec(hdr, sechdrs, secstrings,
diff --git a/kernel/softlockup.c b/kernel/softlockup.c
index 85d5a245510..88796c33083 100644
--- a/kernel/softlockup.c
+++ b/kernel/softlockup.c
@@ -166,97 +166,11 @@ void softlockup_tick(void)
 }
 
 /*
- * Have a reasonable limit on the number of tasks checked:
- */
-unsigned long __read_mostly sysctl_hung_task_check_count = 1024;
-
-/*
- * Zero means infinite timeout - no checking done:
- */
-unsigned long __read_mostly sysctl_hung_task_timeout_secs = 480;
-
-unsigned long __read_mostly sysctl_hung_task_warnings = 10;
-
-/*
- * Only do the hung-tasks check on one CPU:
- */
-static int check_cpu __read_mostly = -1;
-
-static void check_hung_task(struct task_struct *t, unsigned long now)
-{
-	unsigned long switch_count = t->nvcsw + t->nivcsw;
-
-	if (t->flags & PF_FROZEN)
-		return;
-
-	if (switch_count != t->last_switch_count || !t->last_switch_timestamp) {
-		t->last_switch_count = switch_count;
-		t->last_switch_timestamp = now;
-		return;
-	}
-	if ((long)(now - t->last_switch_timestamp) <
-					sysctl_hung_task_timeout_secs)
-		return;
-	if (!sysctl_hung_task_warnings)
-		return;
-	sysctl_hung_task_warnings--;
-
-	/*
-	 * Ok, the task did not get scheduled for more than 2 minutes,
-	 * complain:
-	 */
-	printk(KERN_ERR "INFO: task %s:%d blocked for more than "
-			"%ld seconds.\n", t->comm, t->pid,
-			sysctl_hung_task_timeout_secs);
-	printk(KERN_ERR "\"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\""
-			" disables this message.\n");
-	sched_show_task(t);
-	__debug_show_held_locks(t);
-
-	t->last_switch_timestamp = now;
-	touch_nmi_watchdog();
-
-	if (softlockup_panic)
-		panic("softlockup: blocked tasks");
-}
-
-/*
- * Check whether a TASK_UNINTERRUPTIBLE does not get woken up for
- * a really long time (120 seconds). If that happens, print out
- * a warning.
- */
-static void check_hung_uninterruptible_tasks(int this_cpu)
-{
-	int max_count = sysctl_hung_task_check_count;
-	unsigned long now = get_timestamp(this_cpu);
-	struct task_struct *g, *t;
-
-	/*
-	 * If the system crashed already then all bets are off,
-	 * do not report extra hung tasks:
-	 */
-	if (test_taint(TAINT_DIE) || did_panic)
-		return;
-
-	read_lock(&tasklist_lock);
-	do_each_thread(g, t) {
-		if (!--max_count)
-			goto unlock;
-		/* use "==" to skip the TASK_KILLABLE tasks waiting on NFS */
-		if (t->state == TASK_UNINTERRUPTIBLE)
-			check_hung_task(t, now);
-	} while_each_thread(g, t);
- unlock:
-	read_unlock(&tasklist_lock);
-}
-
-/*
  * The watchdog thread - runs every second and touches the timestamp.
  */
 static int watchdog(void *__bind_cpu)
 {
 	struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
-	int this_cpu = (long)__bind_cpu;
 
 	sched_setscheduler(current, SCHED_FIFO, &param);
 
@@ -276,11 +190,6 @@ static int watchdog(void *__bind_cpu)
 		if (kthread_should_stop())
 			break;
 
-		if (this_cpu == check_cpu) {
-			if (sysctl_hung_task_timeout_secs)
-				check_hung_uninterruptible_tasks(this_cpu);
-		}
-
 		set_current_state(TASK_INTERRUPTIBLE);
 	}
 	__set_current_state(TASK_RUNNING);
@@ -312,18 +221,9 @@ cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
 		break;
 	case CPU_ONLINE:
 	case CPU_ONLINE_FROZEN:
-		check_cpu = cpumask_any(cpu_online_mask);
 		wake_up_process(per_cpu(watchdog_task, hotcpu));
 		break;
 #ifdef CONFIG_HOTPLUG_CPU
-	case CPU_DOWN_PREPARE:
-	case CPU_DOWN_PREPARE_FROZEN:
-		if (hotcpu == check_cpu) {
-			/* Pick any other online cpu. */
-			check_cpu = cpumask_any_but(cpu_online_mask, hotcpu);
-		}
-		break;
-
 	case CPU_UP_CANCELED:
 	case CPU_UP_CANCELED_FROZEN:
 		if (!per_cpu(watchdog_task, hotcpu))
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index b125e338756..4286b62b34a 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -101,6 +101,7 @@ static int __maybe_unused one = 1;
 static int __maybe_unused two = 2;
 static unsigned long one_ul = 1;
 static int one_hundred = 100;
+static int one_thousand = 1000;
 
 /* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */
 static int maxolduid = 65535;
@@ -813,6 +814,19 @@ static struct ctl_table kern_table[] = {
 		.extra1		= &neg_one,
 		.extra2		= &sixty,
 	},
+#endif
+#ifdef CONFIG_DETECT_HUNG_TASK
+	{
+		.ctl_name	= CTL_UNNUMBERED,
+		.procname	= "hung_task_panic",
+		.data		= &sysctl_hung_task_panic,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec_minmax,
+		.strategy	= &sysctl_intvec,
+		.extra1		= &zero,
+		.extra2		= &one,
+	},
 	{
 		.ctl_name	= CTL_UNNUMBERED,
 		.procname	= "hung_task_check_count",
@@ -828,7 +842,7 @@ static struct ctl_table kern_table[] = {
 		.data		= &sysctl_hung_task_timeout_secs,
 		.maxlen		= sizeof(unsigned long),
 		.mode		= 0644,
-		.proc_handler	= &proc_doulongvec_minmax,
+		.proc_handler	= &proc_dohung_task_timeout_secs,
 		.strategy	= &sysctl_intvec,
 	},
 	{
@@ -1027,6 +1041,28 @@ static struct ctl_table vm_table[] = {
 		.proc_handler	= &proc_dointvec,
 	},
 	{
+		.ctl_name	= CTL_UNNUMBERED,
+		.procname	= "nr_pdflush_threads_min",
+		.data		= &nr_pdflush_threads_min,
+		.maxlen		= sizeof nr_pdflush_threads_min,
+		.mode		= 0644 /* read-write */,
+		.proc_handler	= &proc_dointvec_minmax,
+		.strategy	= &sysctl_intvec,
+		.extra1		= &one,
+		.extra2		= &nr_pdflush_threads_max,
+	},
+	{
+		.ctl_name	= CTL_UNNUMBERED,
+		.procname	= "nr_pdflush_threads_max",
+		.data		= &nr_pdflush_threads_max,
+		.maxlen		= sizeof nr_pdflush_threads_max,
+		.mode		= 0644 /* read-write */,
+		.proc_handler	= &proc_dointvec_minmax,
+		.strategy	= &sysctl_intvec,
+		.extra1		= &nr_pdflush_threads_min,
+		.extra2		= &one_thousand,
+	},
+	{
 		.ctl_name	= VM_SWAPPINESS,
 		.procname	= "swappiness",
 		.data		= &vm_swappiness,
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 947c5b3f90c..b32ff446c3f 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -327,10 +327,10 @@ static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
 	char *msg;
 	struct blk_trace *bt;
 
-	if (count > BLK_TN_MAX_MSG)
+	if (count >= BLK_TN_MAX_MSG)
 		return -EINVAL;
 
-	msg = kmalloc(count, GFP_KERNEL);
+	msg = kmalloc(count + 1, GFP_KERNEL);
 	if (msg == NULL)
 		return -ENOMEM;
 
@@ -339,6 +339,7 @@ static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
 		return -EFAULT;
 	}
 
+	msg[count] = '\0';
 	bt = filp->private_data;
 	__trace_note_message(bt, "%s", msg);
 	kfree(msg);
@@ -642,7 +643,7 @@ static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
 	if (blk_pc_request(rq)) {
 		what |= BLK_TC_ACT(BLK_TC_PC);
 		__blk_add_trace(bt, 0, rq->data_len, rw, what, rq->errors,
-				sizeof(rq->cmd), rq->cmd);
+				rq->cmd_len, rq->cmd);
 	} else  {
 		what |= BLK_TC_ACT(BLK_TC_FS);
 		__blk_add_trace(bt, rq->hard_sector, rq->hard_nr_sectors << 9,
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index a0174a40c56..9d28476a985 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -30,6 +30,7 @@
 #include <linux/percpu.h>
 #include <linux/splice.h>
 #include <linux/kdebug.h>
+#include <linux/string.h>
 #include <linux/ctype.h>
 #include <linux/init.h>
 #include <linux/poll.h>
@@ -147,8 +148,7 @@ static int __init set_ftrace_dump_on_oops(char *str)
 }
 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
 
-long
-ns2usecs(cycle_t nsec)
+unsigned long long ns2usecs(cycle_t nsec)
 {
 	nsec += 500;
 	do_div(nsec, 1000);
@@ -1632,7 +1632,11 @@ static void test_cpu_buff_start(struct trace_iterator *iter)
 		return;
 
 	cpumask_set_cpu(iter->cpu, iter->started);
-	trace_seq_printf(s, "##### CPU %u buffer started ####\n", iter->cpu);
+
+	/* Don't print started cpu buffer for the first entry of the trace */
+	if (iter->idx > 1)
+		trace_seq_printf(s, "##### CPU %u buffer started ####\n",
+				iter->cpu);
 }
 
 static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
@@ -1867,6 +1871,11 @@ __tracing_open(struct inode *inode, struct file *file)
 	if (current_trace)
 		*iter->trace = *current_trace;
 
+	if (!alloc_cpumask_var(&iter->started, GFP_KERNEL))
+		goto fail;
+
+	cpumask_clear(iter->started);
+
 	if (current_trace && current_trace->print_max)
 		iter->tr = &max_tr;
 	else
@@ -1917,6 +1926,7 @@ __tracing_open(struct inode *inode, struct file *file)
 		if (iter->buffer_iter[cpu])
 			ring_buffer_read_finish(iter->buffer_iter[cpu]);
 	}
+	free_cpumask_var(iter->started);
  fail:
 	mutex_unlock(&trace_types_lock);
 	kfree(iter->trace);
@@ -1960,6 +1970,7 @@ static int tracing_release(struct inode *inode, struct file *file)
 
 	seq_release(inode, file);
 	mutex_destroy(&iter->mutex);
+	free_cpumask_var(iter->started);
 	kfree(iter->trace);
 	kfree(iter);
 	return 0;
@@ -2358,9 +2369,9 @@ static const char readme_msg[] =
 	"# mkdir /debug\n"
 	"# mount -t debugfs nodev /debug\n\n"
 	"# cat /debug/tracing/available_tracers\n"
-	"wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
+	"wakeup preemptirqsoff preemptoff irqsoff function sched_switch nop\n\n"
 	"# cat /debug/tracing/current_tracer\n"
-	"none\n"
+	"nop\n"
 	"# echo sched_switch > /debug/tracing/current_tracer\n"
 	"# cat /debug/tracing/current_tracer\n"
 	"sched_switch\n"
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index cbc168f1e43..e685ac2b2ba 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -602,7 +602,7 @@ extern int trace_selftest_startup_branch(struct tracer *trace,
 #endif /* CONFIG_FTRACE_STARTUP_TEST */
 
 extern void *head_page(struct trace_array_cpu *data);
-extern long ns2usecs(cycle_t nsec);
+extern unsigned long long ns2usecs(cycle_t nsec);
 extern int
 trace_vbprintk(unsigned long ip, const char *fmt, va_list args);
 extern int
diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c
index 4d9952d3df5..07a22c33ebf 100644
--- a/kernel/trace/trace_export.c
+++ b/kernel/trace/trace_export.c
@@ -40,7 +40,7 @@
 
 #undef TRACE_FIELD_ZERO_CHAR
 #define TRACE_FIELD_ZERO_CHAR(item)					\
-	ret = trace_seq_printf(s, "\tfield: char " #item ";\t"		\
+	ret = trace_seq_printf(s, "\tfield:char " #item ";\t"		\
 			       "offset:%u;\tsize:0;\n",			\
 			       (unsigned int)offsetof(typeof(field), item)); \
 	if (!ret)							\
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index d72b9a63b24..64b54a59c55 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -423,7 +423,7 @@ int trace_print_lat_context(struct trace_iterator *iter)
 
 		trace_find_cmdline(entry->pid, comm);
 
-		ret = trace_seq_printf(s, "%16s %5d %3d %d %08x %08lx [%08lx]"
+		ret = trace_seq_printf(s, "%16s %5d %3d %d %08x %08lx [%08llx]"
 				       " %ld.%03ldms (+%ld.%03ldms): ", comm,
 				       entry->pid, iter->cpu, entry->flags,
 				       entry->preempt_count, iter->idx,
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index de35f200abd..9117cea6f1a 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -62,6 +62,9 @@ probe_sched_wakeup(struct rq *__rq, struct task_struct *wakee, int success)
 	pc = preempt_count();
 	tracing_record_cmdline(current);
 
+	if (sched_stopped)
+		return;
+
 	local_irq_save(flags);
 	cpu = raw_smp_processor_id();
 	data = ctx_trace->data[cpu];
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 3c5ad6b2ec8..5bc00e8f153 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -154,7 +154,7 @@ probe_wakeup_sched_switch(struct rq *rq, struct task_struct *prev,
 	if (unlikely(!tracer_enabled || next != wakeup_task))
 		goto out_unlock;
 
-	trace_function(wakeup_trace, CALLER_ADDR1, CALLER_ADDR2, flags, pc);
+	trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, flags, pc);
 	tracing_sched_switch_trace(wakeup_trace, prev, next, flags, pc);
 
 	/*
@@ -257,6 +257,12 @@ probe_wakeup(struct rq *rq, struct task_struct *p, int success)
 	data = wakeup_trace->data[wakeup_cpu];
 	data->preempt_timestamp = ftrace_now(cpu);
 	tracing_sched_wakeup_trace(wakeup_trace, p, current, flags, pc);
+
+	/*
+	 * We must be careful in using CALLER_ADDR2. But since wake_up
+	 * is not called by an assembly function  (where as schedule is)
+	 * it should be safe to use it here.
+	 */
 	trace_function(wakeup_trace, CALLER_ADDR1, CALLER_ADDR2, flags, pc);
 
 out_locked: