On Wed, 10 Apr 2013, Michael Bohan wrote:
> When switching to a new cpu_base in switch_hrtimer_base(), we
> briefly enable preemption by unlocking the cpu_base lock in two
> places. During this interval it's possible for the running thread
> to be swapped to a different CPU.
>
> Consider the following example:
>
> CPU #0 CPU #1
> ---- ----
> hrtimer_start() ...
> lock_hrtimer_base()
> switch_hrtimer_base()
> this_cpu = 0;
> target_cpu_base = 0;
> raw_spin_unlock(&cpu_base->lock)
> <migrate to CPU 1>
Errm. switch_hrtimer_base() is called with interrupts disabled and
they stay disabled, so how exactly is the task going to be migrated?
Thanks,
tglx
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