Messages in this thread |  | | | Date | Wed, 13 Jan 2010 23:08:49 +0100 (CET) | | From | Thomas Gleixner <> | | Subject | Re: [PATCH] clockevent: don't remove broadcast device when cpu is dead |
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On Wed, 13 Jan 2010, Xiaotian Feng wrote: > On 01/12/2010 09:20 PM, Thomas Gleixner wrote: > > On Thu, 7 Jan 2010, Xiaotian Feng wrote: > > > > > Marc reported BUG during shutdown, after debugging, kernel is trying > > > to remove a broadcast device which mode is CLOCK_EVT_MODE_ONESHOT. > > > > > > The root cause for this bug is that in clockevents_notify, > > > "cpumask_weight(dev->cpumask) == 1" is always true even if dev is a > > > > Why is cpumask_weight(dev->cpumask) == 1 always true when we shutdown > > a non boot cpu ? > > > > The broadcast device is not a per cpu device and the cpumask should > > not only contain the CPU which is shut down ! > > At least for hpet broadcast dev, it's dev->cpumask is only contain the CPU > which it is initialized from.
Which is fundamentaly wrong and the root cause of the problem. I'll have a look tomorrow morning when my brain is more awake than now.
> And for broadcast device, kernel is using tick_broadcast_mask not > dev->cpumask, right?
No, tick_broadcast_mask is the bitmask which tells us which cpus get the broadcast IPI.
Thanks,
tglx
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