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Re: [Xen-devel] [PATCH v3] x86: Fix possible ASSERT(cpu < nr_cpu_ids)

On 19/04/18 14:10, Jan Beulich wrote:
>>>> On 19.04.18 at 12:20, <Davidwang@xxxxxxxxxxx> wrote:
>> From: David Wang <davidwang@xxxxxxxxxxx>
>> CPUs may share an in-use channel. Hence clearing of a bit from
>> the cpumask (in hpet_broadcast_exit()) as well as setting one
>> (in hpet_broadcast_enter()) must not race evaluation of that same
>> cpumask. Therefore avoid evaluating the cpumask twice in
>> hpet_detach_channel(). Otherwise cpumask_empty() may e.g.return
>> false while the subsequent cpumask_first() could return nr_cpu_ids,
>> which then triggers the assertion in cpumask_of() reached through
>> set_channel_irq_affinity().
>> Sign-off-by: David Wang <davidwang@xxxxxxxxxxx>
> Signed-off-by

Release-acked-by: Juergen Gross <jgross@xxxxxxxx>


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