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