Re: clockevents_shutdown vs pending interrupt

From: Thomas Gleixner
Date: Tue Jun 23 2015 - 06:16:03 EST

On Tue, 23 Jun 2015, Andriy Gapon wrote:
> Pardon if I am asking something obvious or silly...
> tick_check_new_device() has the following code:
> if (tick_is_broadcast_device(curdev)) {
> clockevents_shutdown(curdev);
> curdev = NULL;
> }
> and
> void clockevents_shutdown(struct clock_event_device *dev)
> {
> clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
> dev->next_event.tv64 = KTIME_MAX;
> }
> This is all done while interrupts are disabled on the current CPU.
> But what if there is already a pending interrupt from the current source?
> Is it possible that the timer interrupt would be processed by the device that
> was put in the shutdown mode?
> Some context: I am experiencing exactly the same symptoms as described here
> But I run a kernel where
> that bug is fixed. And my problem happens in a VM, so it's possible that there
> are timing issues which are very unlikely on real hardware.

Can you provide a full dmesg please?



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