Merge commit 'v2.6.30-rc6' into perfcounters/core

Merge reason: this branch was on an -rc4 base, merge it up to -rc6
              to get the latest upstream fixes.

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

1 files changed, 11 insertions, 1 deletions

diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index 21a5ca849514..83c4417b6a3c 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -93,7 +93,17 @@ void tick_handle_periodic(struct clock_event_device *dev)
 	for (;;) {
 		if (!clockevents_program_event(dev, next, ktime_get()))
 			return;
-		tick_periodic(cpu);
+		/*
+		 * Have to be careful here. If we're in oneshot mode,
+		 * before we call tick_periodic() in a loop, we need
+		 * to be sure we're using a real hardware clocksource.
+		 * Otherwise we could get trapped in an infinite
+		 * loop, as the tick_periodic() increments jiffies,
+		 * when then will increment time, posibly causing
+		 * the loop to trigger again and again.
+		 */
+		if (timekeeping_valid_for_hres())
+			tick_periodic(cpu);
 		next = ktime_add(next, tick_period);
 	}
 }