On Sat, 18 Jan 2014 04:15:29 +0100
Mike Galbraith [off-list ref] wrote:

 

quoted

So you also have the timers-do-not-raise-softirq-unconditionally.patch?

People have been complaining that the latest 3.12-rt does not boot on
intel i7 boxes. And by reverting this patch, it boots fine.

I happen to have a i7 box to test on, and sure enough, the latest
3.12-rt locks up on boot and reverting the
timers-do-not-raise-softirq-unconditionally.patch, it boots fine.

Looking into it, I made this small update, and the box boots. Seems
checking "active_timers" is not enough to skip raising softirqs. I
haven't looked at why yet, but I would like others to test this patch
too.

I'll leave why this lets i7 boxes boot as an exercise for Thomas ;-)

-- Steve

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/kernel/timer.c b/kernel/timer.c
index 46467be..8212c10 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c

@@ -1464,13 +1464,11 @@ void run_local_timers(void)
 		raise_softirq(TIMER_SOFTIRQ);
 		return;
 	}
-	if (!base->active_timers)
-		goto out;
 
 	/* Check whether the next pending timer has expired */
 	if (time_before_eq(base->next_timer, jiffies))
 		raise_softirq(TIMER_SOFTIRQ);
-out:
+
 	rt_spin_unlock_after_trylock_in_irq(&base->lock);
 
 }