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

Pull timer fixes from Thomas Gleixner:
 "The itimer removal one is not strictly a fix, but I really wanted to
  avoid a rebase of the urgent ones."

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Revert "clocksource: Load the ACPI PM clocksource asynchronously"
  clockevents: tTack broadcast device mode change in tick_broadcast_switch_to_oneshot()
  itimer: Use printk_once instead of WARN_ONCE
  nohz: Fix stale jiffies update in tick_nohz_restart()
  tick: Document TICK_ONESHOT config option
  proc: stats: Use arch_idle_time for idle and iowait times if available
  itimer: Schedule silent NULL pointer fixup in setitimer() for removal

4 files changed, 15 insertions, 5 deletions

diff --git a/kernel/itimer.c b/kernel/itimer.c
index 22000c3db0dd..8d262b467573 100644
--- a/kernel/itimer.c
+++ b/kernel/itimer.c
@@ -284,8 +284,12 @@ SYSCALL_DEFINE3(setitimer, int, which, struct itimerval __user *, value,
 	if (value) {
 		if(copy_from_user(&set_buffer, value, sizeof(set_buffer)))
 			return -EFAULT;
-	} else
-		memset((char *) &set_buffer, 0, sizeof(set_buffer));
+	} else {
+		memset(&set_buffer, 0, sizeof(set_buffer));
+		printk_once(KERN_WARNING "%s calls setitimer() with new_value NULL pointer."
+			    " Misfeature support will be removed\n",
+			    current->comm);
+	}
 
 	error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL);
 	if (error || !ovalue)
diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
index 2cf9cc7aa103..a20dc8a3c949 100644
--- a/kernel/time/Kconfig
+++ b/kernel/time/Kconfig
@@ -1,6 +1,10 @@
 #
 # Timer subsystem related configuration options
 #
+
+# Core internal switch. Selected by NO_HZ / HIGH_RES_TIMERS. This is
+# only related to the tick functionality. Oneshot clockevent devices
+# are supported independ of this.
 config TICK_ONESHOT
 	bool
 
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index e883f57a3cd3..bf57abdc7bd0 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -575,10 +575,12 @@ void tick_broadcast_switch_to_oneshot(void)
 	unsigned long flags;
 
 	raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
+
+	tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT;
+
 	if (cpumask_empty(tick_get_broadcast_mask()))
 		goto end;
 
-	tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT;
 	bc = tick_broadcast_device.evtdev;
 	if (bc)
 		tick_broadcast_setup_oneshot(bc);
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 3526038f2836..6a3a5b9ff561 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -534,9 +534,9 @@ static void tick_nohz_restart(struct tick_sched *ts, ktime_t now)
 				hrtimer_get_expires(&ts->sched_timer), 0))
 				break;
 		}
-		/* Update jiffies and reread time */
-		tick_do_update_jiffies64(now);
+		/* Reread time and update jiffies */
 		now = ktime_get();
+		tick_do_update_jiffies64(now);
 	}
 }