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SubjectRe: 3.10-rc3: WARNING: at kernel/time/tick-broadcast.c:578
> > On Mon, May 27, 2013 at 02:09:33PM +0300, Meelis Roos wrote:
> > > I enabled the new full dynctick on one of my test PCs - Intel 815
> >
> > Do you mean CONFIG_NO_HZ_FULL? If so, it is not enabled in the .config
> > below.

Yes. I meant that - but obviously I did not enable it on this machine. I
enabled it on every machine wehere this was offered for me by make
oldconfig.

> > Also, there are a bunch of timers fixes from Thomas in tip - you could
> > try to merge tip/master ontop of -rc3 and retest.
>
> All related fixes are already in Linus tree.

OK, will not check tip/master.

> That brilliant cpuidle stuff calls
> clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER) twice. So what happens is:
>
> CPU0 CPU1
> cpuidle_idle_call()
> clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER)
> set cpu in tick_broadcast_oneshot_mask
> broadcast interrupt
> event expired for cpu1
> set pending bit
> acpi_idle_enter_simple()
> clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER)
> WARN_ON(pending bit)
>
> So we need to move the WARN_ON into the section where we actually set
> the broadcast stuff up.

Are you sure? This is a UP machine.

Tested the patch - no effect, warning is still there :(

> diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
> index 24938d5..ec21dc0 100644
> --- a/kernel/time/tick-broadcast.c
> +++ b/kernel/time/tick-broadcast.c
> @@ -575,8 +575,8 @@ void tick_broadcast_oneshot_control(unsigned long reason)
>
> raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
> if (reason == CLOCK_EVT_NOTIFY_BROADCAST_ENTER) {
> - WARN_ON_ONCE(cpumask_test_cpu(cpu, tick_broadcast_pending_mask));
> if (!cpumask_test_and_set_cpu(cpu, tick_broadcast_oneshot_mask)) {
> + WARN_ON_ONCE(cpumask_test_cpu(cpu, tick_broadcast_pending_mask));
> clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
> /*
> * We only reprogram the broadcast timer if we
>

--
Meelis Roos (mroos@ut.ee) http://www.cs.ut.ee/~mroos/


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