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

[Wanpeng Li]

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.