Merge branch 'irq/urgent' into irq/core

Reason: Get mainline fixes integrated. Further patches conflict with
        them

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/irq/migration.c

@@ -56,6 +56,7 @@ void move_masked_irq(int irq)
 void move_native_irq(int irq)
 {
 	struct irq_desc *desc = irq_to_desc(irq);
+	bool masked;
 
 	if (likely(!(desc->status & IRQ_MOVE_PENDING)))
 		return;
@@ -63,8 +64,15 @@ void move_native_irq(int irq)
 	if (unlikely(desc->status & IRQ_DISABLED))
 		return;
 
-	desc->irq_data.chip->irq_mask(&desc->irq_data);
+	/*
+	 * Be careful vs. already masked interrupts. If this is a
+	 * threaded interrupt with ONESHOT set, we can end up with an
+	 * interrupt storm.
+	 */
+	masked = desc->status & IRQ_MASKED;
+	if (!masked)
+		desc->irq_data.chip->irq_mask(&desc->irq_data);
 	move_masked_irq(irq);
-	desc->irq_data.chip->irq_unmask(&desc->irq_data);
+	if (!masked)
+		desc->irq_data.chip->irq_unmask(&desc->irq_data);
 }
-

kernel/params.c

@@ -719,9 +719,7 @@ void destroy_params(const struct kernel_param *params, unsigned num)
 			params[i].ops->free(params[i].arg);
 }
 
-static void __init kernel_add_sysfs_param(const char *name,
-					  struct kernel_param *kparam,
-					  unsigned int name_skip)
+static struct module_kobject * __init locate_module_kobject(const char *name)
 {
 	struct module_kobject *mk;
 	struct kobject *kobj;
@@ -729,10 +727,7 @@ static void __init kernel_add_sysfs_param(const char *name,
 
 	kobj = kset_find_obj(module_kset, name);
 	if (kobj) {
-		/* We already have one.  Remove params so we can add more. */
 		mk = to_module_kobject(kobj);
-		/* We need to remove it before adding parameters. */
-		sysfs_remove_group(&mk->kobj, &mk->mp->grp);
 	} else {
 		mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
 		BUG_ON(!mk);
@@ -743,15 +738,36 @@ static void __init kernel_add_sysfs_param(const char *name,
 					   "%s", name);
 		if (err) {
 			kobject_put(&mk->kobj);
-			printk(KERN_ERR "Module '%s' failed add to sysfs, "
-			       "error number %d\n", name, err);
-			printk(KERN_ERR	"The system will be unstable now.\n");
-			return;
+			printk(KERN_ERR
+				"Module '%s' failed add to sysfs, error number %d\n",
+				name, err);
+			printk(KERN_ERR
+				"The system will be unstable now.\n");
+			return NULL;
 		}
-		/* So that exit path is even. */
+
+		/* So that we hold reference in both cases. */
 		kobject_get(&mk->kobj);
 	}
 
+	return mk;
+}
+
+static void __init kernel_add_sysfs_param(const char *name,
+					  struct kernel_param *kparam,
+					  unsigned int name_skip)
+{
+	struct module_kobject *mk;
+	int err;
+
+	mk = locate_module_kobject(name);
+	if (!mk)
+		return;
+
+	/* We need to remove old parameters before adding more. */
+	if (mk->mp)
+		sysfs_remove_group(&mk->kobj, &mk->mp->grp);
+
 	/* These should not fail at boot. */
 	err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
 	BUG_ON(err);
@@ -796,6 +812,32 @@ static void __init param_sysfs_builtin(void)
 	}
 }
 
+ssize_t __modver_version_show(struct module_attribute *mattr,
+			      struct module *mod, char *buf)
+{
+	struct module_version_attribute *vattr =
+		container_of(mattr, struct module_version_attribute, mattr);
+
+	return sprintf(buf, "%s\n", vattr->version);
+}
+
+extern struct module_version_attribute __start___modver[], __stop___modver[];
+
+static void __init version_sysfs_builtin(void)
+{
+	const struct module_version_attribute *vattr;
+	struct module_kobject *mk;
+	int err;
+
+	for (vattr = __start___modver; vattr < __stop___modver; vattr++) {
+		mk = locate_module_kobject(vattr->module_name);
+		if (mk) {
+			err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
+			kobject_uevent(&mk->kobj, KOBJ_ADD);
+			kobject_put(&mk->kobj);
+		}
+	}
+}
 
 /* module-related sysfs stuff */
 
@@ -875,6 +917,7 @@ static int __init param_sysfs_init(void)
 	}
 	module_sysfs_initialized = 1;
 
+	version_sysfs_builtin();
 	param_sysfs_builtin();
 
 	return 0;

kernel/perf_event.c

@@ -1901,11 +1901,12 @@ static void __perf_event_read(void *info)
 		return;
 
 	raw_spin_lock(&ctx->lock);
-	update_context_time(ctx);
+	if (ctx->is_active)
+		update_context_time(ctx);
 	update_event_times(event);
+	if (event->state == PERF_EVENT_STATE_ACTIVE)
+		event->pmu->read(event);
 	raw_spin_unlock(&ctx->lock);
-
-	event->pmu->read(event);
 }
 
 static inline u64 perf_event_count(struct perf_event *event)
@@ -1999,8 +2000,7 @@ static int alloc_callchain_buffers(void)
 	 * accessed from NMI. Use a temporary manual per cpu allocation
 	 * until that gets sorted out.
 	 */
-	size = sizeof(*entries) + sizeof(struct perf_callchain_entry *) *
-		num_possible_cpus();
+	size = offsetof(struct callchain_cpus_entries, cpu_entries[nr_cpu_ids]);
 
 	entries = kzalloc(size, GFP_KERNEL);
 	if (!entries)
@@ -2201,13 +2201,6 @@ find_lively_task_by_vpid(pid_t vpid)
 	if (!task)
 		return ERR_PTR(-ESRCH);
 
-	/*
-	 * Can't attach events to a dying task.
-	 */
-	err = -ESRCH;
-	if (task->flags & PF_EXITING)
-		goto errout;
-
 	/* Reuse ptrace permission checks for now. */
 	err = -EACCES;
 	if (!ptrace_may_access(task, PTRACE_MODE_READ))
@@ -2268,14 +2261,27 @@ retry:
 
 		get_ctx(ctx);
 
-		if (cmpxchg(&task->perf_event_ctxp[ctxn], NULL, ctx)) {
-			/*
-			 * We raced with some other task; use
-			 * the context they set.
-			 */
+		err = 0;
+		mutex_lock(&task->perf_event_mutex);
+		/*
+		 * If it has already passed perf_event_exit_task().
+		 * we must see PF_EXITING, it takes this mutex too.
+		 */
+		if (task->flags & PF_EXITING)
+			err = -ESRCH;
+		else if (task->perf_event_ctxp[ctxn])
+			err = -EAGAIN;
+		else
+			rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
+		mutex_unlock(&task->perf_event_mutex);
+
+		if (unlikely(err)) {
 			put_task_struct(task);
 			kfree(ctx);
-			goto retry;
+
+			if (err == -EAGAIN)
+				goto retry;
+			goto errout;
 		}
 	}
 
@@ -5374,6 +5380,8 @@ free_dev:
 	goto out;
 }
 
+static struct lock_class_key cpuctx_mutex;
+
 int perf_pmu_register(struct pmu *pmu, char *name, int type)
 {
 	int cpu, ret;
@@ -5422,6 +5430,7 @@ skip_type:
 
 		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
 		__perf_event_init_context(&cpuctx->ctx);
+		lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
 		cpuctx->ctx.type = cpu_context;
 		cpuctx->ctx.pmu = pmu;
 		cpuctx->jiffies_interval = 1;
@@ -6127,7 +6136,7 @@ static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
 	 * scheduled, so we are now safe from rescheduling changing
 	 * our context.
 	 */
-	child_ctx = child->perf_event_ctxp[ctxn];
+	child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]);
 	task_ctx_sched_out(child_ctx, EVENT_ALL);
 
 	/*
@@ -6440,11 +6449,6 @@ int perf_event_init_context(struct task_struct *child, int ctxn)
 	unsigned long flags;
 	int ret = 0;
 
-	child->perf_event_ctxp[ctxn] = NULL;
-
-	mutex_init(&child->perf_event_mutex);
-	INIT_LIST_HEAD(&child->perf_event_list);
-
 	if (likely(!parent->perf_event_ctxp[ctxn]))
 		return 0;
 
@@ -6533,6 +6537,10 @@ int perf_event_init_task(struct task_struct *child)
 {
 	int ctxn, ret;
 
+	memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
+	mutex_init(&child->perf_event_mutex);
+	INIT_LIST_HEAD(&child->perf_event_list);
+
 	for_each_task_context_nr(ctxn) {
 		ret = perf_event_init_context(child, ctxn);
 		if (ret)

kernel/printk.c

@@ -97,7 +97,7 @@ static int console_locked, console_suspended;
 /*
  * logbuf_lock protects log_buf, log_start, log_end, con_start and logged_chars
  * It is also used in interesting ways to provide interlocking in
- * release_console_sem().
+ * console_unlock();.
  */
 static DEFINE_SPINLOCK(logbuf_lock);
 
@@ -501,7 +501,7 @@ static void _call_console_drivers(unsigned start,
 /*
  * Call the console drivers, asking them to write out
  * log_buf[start] to log_buf[end - 1].
- * The console_sem must be held.
+ * The console_lock must be held.
  */
 static void call_console_drivers(unsigned start, unsigned end)
 {
@@ -604,11 +604,11 @@ static int have_callable_console(void)
  *
  * This is printk().  It can be called from any context.  We want it to work.
  *
- * We try to grab the console_sem.  If we succeed, it's easy - we log the output and
+ * We try to grab the console_lock.  If we succeed, it's easy - we log the output and
  * call the console drivers.  If we fail to get the semaphore we place the output
  * into the log buffer and return.  The current holder of the console_sem will
- * notice the new output in release_console_sem() and will send it to the
- * consoles before releasing the semaphore.
+ * notice the new output in console_unlock(); and will send it to the
+ * consoles before releasing the lock.
  *
  * One effect of this deferred printing is that code which calls printk() and
  * then changes console_loglevel may break. This is because console_loglevel
@@ -659,19 +659,19 @@ static inline int can_use_console(unsigned int cpu)
 /*
  * Try to get console ownership to actually show the kernel
  * messages from a 'printk'. Return true (and with the
- * console_semaphore held, and 'console_locked' set) if it
+ * console_lock held, and 'console_locked' set) if it
  * is successful, false otherwise.
  *
  * This gets called with the 'logbuf_lock' spinlock held and
  * interrupts disabled. It should return with 'lockbuf_lock'
  * released but interrupts still disabled.
  */
-static int acquire_console_semaphore_for_printk(unsigned int cpu)
+static int console_trylock_for_printk(unsigned int cpu)
 	__releases(&logbuf_lock)
 {
 	int retval = 0;
 
-	if (!try_acquire_console_sem()) {
+	if (console_trylock()) {
 		retval = 1;
 
 		/*
@@ -827,12 +827,12 @@ asmlinkage int vprintk(const char *fmt, va_list args)
 	 * actual magic (print out buffers, wake up klogd,
 	 * etc). 
 	 *
-	 * The acquire_console_semaphore_for_printk() function
+	 * The console_trylock_for_printk() function
 	 * will release 'logbuf_lock' regardless of whether it
 	 * actually gets the semaphore or not.
 	 */
-	if (acquire_console_semaphore_for_printk(this_cpu))
-		release_console_sem();
+	if (console_trylock_for_printk(this_cpu))
+		console_unlock();
 
 	lockdep_on();
 out_restore_irqs:
@@ -993,7 +993,7 @@ void suspend_console(void)
 	if (!console_suspend_enabled)
 		return;
 	printk("Suspending console(s) (use no_console_suspend to debug)\n");
-	acquire_console_sem();
+	console_lock();
 	console_suspended = 1;
 	up(&console_sem);
 }
@@ -1004,7 +1004,7 @@ void resume_console(void)
 		return;
 	down(&console_sem);
 	console_suspended = 0;
-	release_console_sem();
+	console_unlock();
 }
 
 /**
@@ -1027,21 +1027,21 @@ static int __cpuinit console_cpu_notify(struct notifier_block *self,
 	case CPU_DYING:
 	case CPU_DOWN_FAILED:
 	case CPU_UP_CANCELED:
-		acquire_console_sem();
-		release_console_sem();
+		console_lock();
+		console_unlock();
 	}
 	return NOTIFY_OK;
 }
 
 /**
- * acquire_console_sem - lock the console system for exclusive use.
+ * console_lock - lock the console system for exclusive use.
  *
- * Acquires a semaphore which guarantees that the caller has
+ * Acquires a lock which guarantees that the caller has
  * exclusive access to the console system and the console_drivers list.
  *
  * Can sleep, returns nothing.
  */
-void acquire_console_sem(void)
+void console_lock(void)
 {
 	BUG_ON(in_interrupt());
 	down(&console_sem);
@@ -1050,21 +1050,29 @@ void acquire_console_sem(void)
 	console_locked = 1;
 	console_may_schedule = 1;
 }
-EXPORT_SYMBOL(acquire_console_sem);
+EXPORT_SYMBOL(console_lock);
 
-int try_acquire_console_sem(void)
+/**
+ * console_trylock - try to lock the console system for exclusive use.
+ *
+ * Tried to acquire a lock which guarantees that the caller has
+ * exclusive access to the console system and the console_drivers list.
+ *
+ * returns 1 on success, and 0 on failure to acquire the lock.
+ */
+int console_trylock(void)
 {
 	if (down_trylock(&console_sem))
-		return -1;
+		return 0;
 	if (console_suspended) {
 		up(&console_sem);
-		return -1;
+		return 0;
 	}
 	console_locked = 1;
 	console_may_schedule = 0;
-	return 0;
+	return 1;
 }
-EXPORT_SYMBOL(try_acquire_console_sem);
+EXPORT_SYMBOL(console_trylock);
 
 int is_console_locked(void)
 {
@@ -1095,20 +1103,20 @@ void wake_up_klogd(void)
 }
 
 /**
- * release_console_sem - unlock the console system
+ * console_unlock - unlock the console system
  *
- * Releases the semaphore which the caller holds on the console system
+ * Releases the console_lock which the caller holds on the console system
  * and the console driver list.
  *
- * While the semaphore was held, console output may have been buffered
- * by printk().  If this is the case, release_console_sem() emits
- * the output prior to releasing the semaphore.
+ * While the console_lock was held, console output may have been buffered
+ * by printk().  If this is the case, console_unlock(); emits
+ * the output prior to releasing the lock.
  *
  * If there is output waiting for klogd, we wake it up.
  *
- * release_console_sem() may be called from any context.
+ * console_unlock(); may be called from any context.
  */
-void release_console_sem(void)
+void console_unlock(void)
 {
 	unsigned long flags;
 	unsigned _con_start, _log_end;
@@ -1141,7 +1149,7 @@ void release_console_sem(void)
 	if (wake_klogd)
 		wake_up_klogd();
 }
-EXPORT_SYMBOL(release_console_sem);
+EXPORT_SYMBOL(console_unlock);
 
 /**
  * console_conditional_schedule - yield the CPU if required
@@ -1150,7 +1158,7 @@ EXPORT_SYMBOL(release_console_sem);
  * if this CPU should yield the CPU to another task, do
  * so here.
  *
- * Must be called within acquire_console_sem().
+ * Must be called within console_lock();.
  */
 void __sched console_conditional_schedule(void)
 {
@@ -1171,14 +1179,14 @@ void console_unblank(void)
 		if (down_trylock(&console_sem) != 0)
 			return;
 	} else
-		acquire_console_sem();
+		console_lock();
 
 	console_locked = 1;
 	console_may_schedule = 0;
 	for_each_console(c)
 		if ((c->flags & CON_ENABLED) && c->unblank)
 			c->unblank();
-	release_console_sem();
+	console_unlock();
 }
 
 /*
@@ -1189,7 +1197,7 @@ struct tty_driver *console_device(int *index)
 	struct console *c;
 	struct tty_driver *driver = NULL;
 
-	acquire_console_sem();
+	console_lock();
 	for_each_console(c) {
 		if (!c->device)
 			continue;
@@ -1197,7 +1205,7 @@ struct tty_driver *console_device(int *index)
 		if (driver)
 			break;
 	}
-	release_console_sem();
+	console_unlock();
 	return driver;
 }
 
@@ -1208,17 +1216,17 @@ struct tty_driver *console_device(int *index)
  */
 void console_stop(struct console *console)
 {
-	acquire_console_sem();
+	console_lock();
 	console->flags &= ~CON_ENABLED;
-	release_console_sem();
+	console_unlock();
 }
 EXPORT_SYMBOL(console_stop);
 
 void console_start(struct console *console)
 {
-	acquire_console_sem();
+	console_lock();
 	console->flags |= CON_ENABLED;
-	release_console_sem();
+	console_unlock();
 }
 EXPORT_SYMBOL(console_start);
 
@@ -1340,7 +1348,7 @@ void register_console(struct console *newcon)
 	 *	Put this console in the list - keep the
 	 *	preferred driver at the head of the list.
 	 */
-	acquire_console_sem();
+	console_lock();
 	if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) {
 		newcon->next = console_drivers;
 		console_drivers = newcon;
@@ -1352,14 +1360,14 @@ void register_console(struct console *newcon)
 	}
 	if (newcon->flags & CON_PRINTBUFFER) {
 		/*
-		 * release_console_sem() will print out the buffered messages
+		 * console_unlock(); will print out the buffered messages
 		 * for us.
 		 */
 		spin_lock_irqsave(&logbuf_lock, flags);
 		con_start = log_start;
 		spin_unlock_irqrestore(&logbuf_lock, flags);
 	}
-	release_console_sem();
+	console_unlock();
 	console_sysfs_notify();
 
 	/*
@@ -1396,7 +1404,7 @@ int unregister_console(struct console *console)
 		return braille_unregister_console(console);
 #endif
 
-	acquire_console_sem();
+	console_lock();
 	if (console_drivers == console) {
 		console_drivers=console->next;
 		res = 0;
@@ -1418,7 +1426,7 @@ int unregister_console(struct console *console)
 	if (console_drivers != NULL && console->flags & CON_CONSDEV)
 		console_drivers->flags |= CON_CONSDEV;
 
-	release_console_sem();
+	console_unlock();
 	console_sysfs_notify();
 	return res;
 }

kernel/sched_fair.c

@@ -699,7 +699,8 @@ account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
 	cfs_rq->nr_running--;
 }
 
-#if defined CONFIG_SMP && defined CONFIG_FAIR_GROUP_SCHED
+#ifdef CONFIG_FAIR_GROUP_SCHED
+# ifdef CONFIG_SMP
 static void update_cfs_rq_load_contribution(struct cfs_rq *cfs_rq,
 					    int global_update)
 {
@@ -721,10 +722,10 @@ static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
 	u64 now, delta;
 	unsigned long load = cfs_rq->load.weight;
 
-	if (!cfs_rq)
+	if (cfs_rq->tg == &root_task_group)
 		return;
 
-	now = rq_of(cfs_rq)->clock;
+	now = rq_of(cfs_rq)->clock_task;
 	delta = now - cfs_rq->load_stamp;
 
 	/* truncate load history at 4 idle periods */
@@ -762,6 +763,51 @@ static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
 		list_del_leaf_cfs_rq(cfs_rq);
 }
 
+static long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg,
+				long weight_delta)
+{
+	long load_weight, load, shares;
+
+	load = cfs_rq->load.weight + weight_delta;
+
+	load_weight = atomic_read(&tg->load_weight);
+	load_weight -= cfs_rq->load_contribution;
+	load_weight += load;
+
+	shares = (tg->shares * load);
+	if (load_weight)
+		shares /= load_weight;
+
+	if (shares < MIN_SHARES)
+		shares = MIN_SHARES;
+	if (shares > tg->shares)
+		shares = tg->shares;
+
+	return shares;
+}
+
+static void update_entity_shares_tick(struct cfs_rq *cfs_rq)
+{
+	if (cfs_rq->load_unacc_exec_time > sysctl_sched_shares_window) {
+		update_cfs_load(cfs_rq, 0);
+		update_cfs_shares(cfs_rq, 0);
+	}
+}
+# else /* CONFIG_SMP */
+static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
+{
+}
+
+static inline long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg,
+				long weight_delta)
+{
+	return tg->shares;
+}
+
+static inline void update_entity_shares_tick(struct cfs_rq *cfs_rq)
+{
+}
+# endif /* CONFIG_SMP */
 static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
 			    unsigned long weight)
 {
@@ -782,41 +828,20 @@ static void update_cfs_shares(struct cfs_rq *cfs_rq, long weight_delta)
 {
 	struct task_group *tg;
 	struct sched_entity *se;
-	long load_weight, load, shares;
-
-	if (!cfs_rq)
-		return;
+	long shares;
 
 	tg = cfs_rq->tg;
 	se = tg->se[cpu_of(rq_of(cfs_rq))];
 	if (!se)
 		return;
-
-	load = cfs_rq->load.weight + weight_delta;
-
-	load_weight = atomic_read(&tg->load_weight);
-	load_weight -= cfs_rq->load_contribution;
-	load_weight += load;
-
-	shares = (tg->shares * load);
-	if (load_weight)
-		shares /= load_weight;
-
-	if (shares < MIN_SHARES)
-		shares = MIN_SHARES;
-	if (shares > tg->shares)
-		shares = tg->shares;
+#ifndef CONFIG_SMP
+	if (likely(se->load.weight == tg->shares))
+		return;
+#endif
+	shares = calc_cfs_shares(cfs_rq, tg, weight_delta);
 
 	reweight_entity(cfs_rq_of(se), se, shares);
 }
-
-static void update_entity_shares_tick(struct cfs_rq *cfs_rq)
-{
-	if (cfs_rq->load_unacc_exec_time > sysctl_sched_shares_window) {
-		update_cfs_load(cfs_rq, 0);
-		update_cfs_shares(cfs_rq, 0);
-	}
-}
 #else /* CONFIG_FAIR_GROUP_SCHED */
 static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
 {
@@ -1404,7 +1429,7 @@ static inline unsigned long effective_load(struct task_group *tg, int cpu,
 
 static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
 {
-	unsigned long this_load, load;
+	s64 this_load, load;
 	int idx, this_cpu, prev_cpu;
 	unsigned long tl_per_task;
 	struct task_group *tg;
@@ -1443,8 +1468,8 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
 	 * Otherwise check if either cpus are near enough in load to allow this
 	 * task to be woken on this_cpu.
 	 */
-	if (this_load) {
-		unsigned long this_eff_load, prev_eff_load;
+	if (this_load > 0) {
+		s64 this_eff_load, prev_eff_load;
 
 		this_eff_load = 100;
 		this_eff_load *= power_of(prev_cpu);

kernel/sched_rt.c

@@ -625,7 +625,7 @@ static void update_curr_rt(struct rq *rq)
 	struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
 	u64 delta_exec;
 
-	if (!task_has_rt_policy(curr))
+	if (curr->sched_class != &rt_sched_class)
 		return;
 
 	delta_exec = rq->clock_task - curr->se.exec_start;

kernel/sys.c

@@ -1385,7 +1385,8 @@ static int check_prlimit_permission(struct task_struct *task)
 	const struct cred *cred = current_cred(), *tcred;
 
 	tcred = __task_cred(task);
-	if ((cred->uid != tcred->euid ||
+	if (current != task &&
+	    (cred->uid != tcred->euid ||
 	     cred->uid != tcred->suid ||
 	     cred->uid != tcred->uid  ||
 	     cred->gid != tcred->egid ||

kernel/sysctl.c

@@ -170,7 +170,8 @@ static int proc_taint(struct ctl_table *table, int write,
 #endif
 
 #ifdef CONFIG_MAGIC_SYSRQ
-static int __sysrq_enabled; /* Note: sysrq code ises it's own private copy */
+/* Note: sysrq code uses it's own private copy */
+static int __sysrq_enabled = SYSRQ_DEFAULT_ENABLE;
 
 static int sysrq_sysctl_handler(ctl_table *table, int write,
 				void __user *buffer, size_t *lenp,

kernel/time/tick-sched.c

@@ -642,8 +642,7 @@ static void tick_nohz_switch_to_nohz(void)
 	}
 	local_irq_enable();
 
-	printk(KERN_INFO "Switched to NOHz mode on CPU #%d\n",
-	       smp_processor_id());
+	printk(KERN_INFO "Switched to NOHz mode on CPU #%d\n", smp_processor_id());
 }
 
 /*
@@ -795,8 +794,10 @@ void tick_setup_sched_timer(void)
 	}
 
 #ifdef CONFIG_NO_HZ
-	if (tick_nohz_enabled)
+	if (tick_nohz_enabled) {
 		ts->nohz_mode = NOHZ_MODE_HIGHRES;
+		printk(KERN_INFO "Switched to NOHz mode on CPU #%d\n", smp_processor_id());
+	}
 #endif
 }
 #endif /* HIGH_RES_TIMERS */

kernel/watchdog.c

@@ -27,7 +27,7 @@
 #include <asm/irq_regs.h>
 #include <linux/perf_event.h>
 
-int watchdog_enabled;
+int watchdog_enabled = 1;
 int __read_mostly softlockup_thresh = 60;
 
 static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts);
@@ -43,9 +43,6 @@ static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts_saved);
 static DEFINE_PER_CPU(struct perf_event *, watchdog_ev);
 #endif
 
-static int no_watchdog;
-
-
 /* boot commands */
 /*
  * Should we panic when a soft-lockup or hard-lockup occurs:
@@ -58,7 +55,7 @@ static int __init hardlockup_panic_setup(char *str)
 	if (!strncmp(str, "panic", 5))
 		hardlockup_panic = 1;
 	else if (!strncmp(str, "0", 1))
-		no_watchdog = 1;
+		watchdog_enabled = 0;
 	return 1;
 }
 __setup("nmi_watchdog=", hardlockup_panic_setup);
@@ -77,7 +74,7 @@ __setup("softlockup_panic=", softlockup_panic_setup);
 
 static int __init nowatchdog_setup(char *str)
 {
-	no_watchdog = 1;
+	watchdog_enabled = 0;
 	return 1;
 }
 __setup("nowatchdog", nowatchdog_setup);
@@ -85,7 +82,7 @@ __setup("nowatchdog", nowatchdog_setup);
 /* deprecated */
 static int __init nosoftlockup_setup(char *str)
 {
-	no_watchdog = 1;
+	watchdog_enabled = 0;
 	return 1;
 }
 __setup("nosoftlockup", nosoftlockup_setup);
@@ -432,9 +429,6 @@ static int watchdog_enable(int cpu)
 		wake_up_process(p);
 	}
 
-	/* if any cpu succeeds, watchdog is considered enabled for the system */
-	watchdog_enabled = 1;
-
 	return 0;
 }
 
@@ -462,12 +456,16 @@ static void watchdog_disable(int cpu)
 static void watchdog_enable_all_cpus(void)
 {
 	int cpu;
-	int result = 0;
+
+	watchdog_enabled = 0;
 
 	for_each_online_cpu(cpu)
-		result += watchdog_enable(cpu);
+		if (!watchdog_enable(cpu))
+			/* if any cpu succeeds, watchdog is considered
+			   enabled for the system */
+			watchdog_enabled = 1;
 
-	if (result)
+	if (!watchdog_enabled)
 		printk(KERN_ERR "watchdog: failed to be enabled on some cpus\n");
 
 }
@@ -476,9 +474,6 @@ static void watchdog_disable_all_cpus(void)
 {
 	int cpu;
 
-	if (no_watchdog)
-		return;
-
 	for_each_online_cpu(cpu)
 		watchdog_disable(cpu);
 
@@ -498,10 +493,12 @@ int proc_dowatchdog_enabled(struct ctl_table *table, int write,
 {
 	proc_dointvec(table, write, buffer, length, ppos);
 
-	if (watchdog_enabled)
-		watchdog_enable_all_cpus();
-	else
-		watchdog_disable_all_cpus();
+	if (write) {
+		if (watchdog_enabled)
+			watchdog_enable_all_cpus();
+		else
+			watchdog_disable_all_cpus();
+	}
 	return 0;
 }
 
@@ -530,7 +527,8 @@ cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
 		break;
 	case CPU_ONLINE:
 	case CPU_ONLINE_FROZEN:
-		err = watchdog_enable(hotcpu);
+		if (watchdog_enabled)
+			err = watchdog_enable(hotcpu);
 		break;
 #ifdef CONFIG_HOTPLUG_CPU
 	case CPU_UP_CANCELED:
@@ -555,9 +553,6 @@ void __init lockup_detector_init(void)
 	void *cpu = (void *)(long)smp_processor_id();
 	int err;
 
-	if (no_watchdog)
-		return;
-
 	err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
 	WARN_ON(notifier_to_errno(err));