From: Wanpeng Li <kernellwp@gmail.com>
To: Nitesh Narayan Lal <nitesh@redhat.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
KVM list <kvm@vger.kernel.org>,
Wanpeng Li <wanpengli@tencent.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Liran Alon <liran.alon@oracle.com>,
"frederic@kernel.org" <frederic@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Juri Lelli <juri.lelli@redhat.com>
Subject: Re: WARNING: suspicious RCU usage - while installing a VM on a CPU listed under nohz_full
Date: Wed, 29 Jul 2020 09:00:22 +0800 [thread overview]
Message-ID: <CANRm+Cywhi1p5gYLfG=JcyTdYuWK+9bGqF6HD-LiBJM9Q5ykNQ@mail.gmail.com> (raw)
In-Reply-To: <ece36eb1-253a-8ec6-c183-309c10bb35d5@redhat.com>
On Tue, 28 Jul 2020 at 22:40, Nitesh Narayan Lal <nitesh@redhat.com> 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.
I still can reproduce this after removing the ipi/timer fastpath
codes, anyway, I will have a look.
next prev parent reply other threads:[~2020-07-29 1:00 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-28 14:39 WARNING: suspicious RCU usage - while installing a VM on a CPU listed under nohz_full Nitesh Narayan Lal
2020-07-29 1:00 ` Wanpeng Li [this message]
2020-07-29 2:38 ` Wanpeng Li
2020-07-29 12:34 ` Nitesh Narayan Lal
2020-07-30 22:45 ` Nitesh Narayan Lal
2020-07-31 7:42 ` Wanpeng Li
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