From: Thomas Gleixner <tglx@linutronix.de>
To: Feng Tang <feng.tang@intel.com>
Cc: "Chen, Rong A" <rong.a.chen@intel.com>,
"tipbuild@zytor.com" <tipbuild@zytor.com>,
Ingo Molnar <mingo@kernel.org>, "lkp@01.org" <lkp@01.org>,
LKML <linux-kernel@vger.kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org
Subject: Re: [LKP] [x86/hotplug] e1056a25da: WARNING:at_arch/x86/kernel/apic/apic.c:#setup_local_APIC
Date: Sat, 29 Jun 2019 09:15:17 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.21.1906290912390.1802@nanos.tec.linutronix.de> (raw)
In-Reply-To: <alpine.DEB.2.21.1906280929010.32342@nanos.tec.linutronix.de>
Feng,
On Fri, 28 Jun 2019, Thomas Gleixner wrote:
> On Fri, 28 Jun 2019, Feng Tang wrote:
> > On Tue, Jun 25, 2019 at 07:32:03PM +0800, Thomas Gleixner wrote:
> > > the head of that branch is:
> > >
> > > 4f3f6d6a7f8e ("x86/apic/x2apic: Add conditional IPI shorthands support")
> > >
> > > This is WIP and force pushed. There are no incremental changes. Could you
> > > please check again?
> >
> > Since you can't reproduce it yet, we've added some debug hook to get more
> > info, like dmesg below:
> >
> > [ 288.866069] IRR[7]: 0x1000
> > [ 289.890274] WARNING: CPU: 0 PID: 0 at arch/x86/kernel/apic/apic.c:1502 setup_local_APIC+0x2d1/0x4f0
>
> > [ 290.182418] queued = 0x1000 acked = 0
> > [ 290.189159] IRR[7]: 0x1000
> >
> > Which shows the IRR[7] was set 0x1000, IIUC, it means vector
> > 0xec, which is for LAPIC timer, and ISRs are all 0 before and
> > after the loop.
>
> Ahhhh. That makes a lot of sense now.
>
> That interrupt is in the IRR, but not in the ISR. So the acknowledge
> attempts are useless because the ack only clears an pending ISR and the IRR
> is not propagated because in the state in which this happens the entry is
> masked.
>
> That function just 'works' by chance not by design. I'll stare into it and
> fix it up for real.
>
> Thank you very much for that information. Your debug was spot on!
I rewrote that function so it actually handles that case correctly along
with some other things which were broken and force pushed the WIP.x86/ipi
branch.
Can you please run exactly that test again against that new version and
verify that this is fixed now?
Thanks,
tglx
next prev parent reply other threads:[~2019-06-29 7:15 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-20 2:18 [x86/hotplug] e1056a25da: WARNING:at_arch/x86/kernel/apic/apic.c:#setup_local_APIC kernel test robot
2019-06-21 19:08 ` Thomas Gleixner
2019-06-25 1:46 ` Rong Chen
2019-06-25 6:24 ` Thomas Gleixner
2019-06-25 8:40 ` [LKP] " Rong Chen
2019-06-25 11:32 ` Thomas Gleixner
2019-06-26 1:19 ` Rong Chen
2019-06-27 14:26 ` Thomas Gleixner
2019-06-28 8:51 ` Rong Chen
2019-06-28 6:32 ` Feng Tang
2019-06-28 9:19 ` Thomas Gleixner
2019-06-29 7:15 ` Thomas Gleixner [this message]
2019-06-30 11:35 ` Thomas Gleixner
2019-06-30 13:03 ` Feng Tang
2019-06-30 18:21 ` Thomas Gleixner
2019-07-01 7:13 ` Thomas Gleixner
2019-07-01 8:36 ` Feng Tang
2019-07-01 9:26 ` Thomas Gleixner
2019-07-01 9:44 ` Rong Chen
2019-07-01 22:41 ` [BUG] kvm: APIC emulation problem - was Re: [LKP] [x86/hotplug] Thomas Gleixner
2019-07-02 5:29 ` Wanpeng Li
2019-07-02 6:40 ` Thomas Gleixner
2019-07-02 9:44 ` Wanpeng Li
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