Re: WARNING: suspicious RCU usage - while installing a VM on a CPU listed under nohz_full

[Nitesh Narayan Lal]

On 7/28/20 10:38 PM, Wanpeng Li wrote:
> Hi Niteshï
> On Wed, 29 Jul 2020 at 09:00, Wanpeng Li <kernellwp@xxxxxxxxx> wrote:
>> On Tue, 28 Jul 2020 at 22:40, Nitesh Narayan Lal <nitesh@xxxxxxxxxx> wrote:
>>> Hi,
>>>
>>> I have recently come across an RCU trace with the 5.8-rc7 kernel that has the
>>> debug configs enabled while installing a VM on a CPU that is listed under
>>> nohz_full.
>>>
>>> Based on some of the initial debugging, my impression is that the issue is
>>> triggered because of the fastpath that is meant to optimize the writes to x2APIC
>>> ICR that eventually leads to a virtual IPI in fixed delivery mode, is getting
>>> invoked from the quiescent state.
> Could you try latest linux-next tree? I guess maybe some patches are
> pending in linux-next tree, I can't reproduce against linux-next tree.

Sure, I will try this today.

>
-- 
Nitesh

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