linux-kernel - Re: [PATCH v5 0/6] x86/apic: Fix restoring boot irq mode in reboot and kexec/kdump

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Date:   Fri, 16 Feb 2018 18:24:37 +0800
From:   Baoquan He <bhe@...hat.com>
To:     ebiederm@...ssion.com, Ingo Molnar <mingo@...nel.org>
Cc:     linux-kernel@...r.kernel.org, tglx@...utronix.de, x86@...nel.org,
        douly.fnst@...fujitsu.com, joro@...tes.org, uobergfe@...hat.com,
        prarit@...hat.com
Subject: Re: [PATCH v5 0/6] x86/apic: Fix restoring boot irq mode in reboot
 and kexec/kdump

Hi Ingo, Eric,

On 02/16/18 at 10:38am, Ingo Molnar wrote:
> 
> * Baoquan He <bhe@...hat.com> wrote:
> 
> > This is v5 post. Newly added patch 0002 includes the change
> > related to KEXEC_JUMP path. Patch 0003 only includes the
> > regression fix.
> > 
> > A regression bug was introduced in below commit.
> > commit 522e66464467 ("x86/apic: Disable I/O APIC before shutdown of the local APIC")
> > 
> > It caused the action to fail that we try to restore boot irq mode
> > in reboot and kexec/kdump. Details can be seen in patch 0003.
> > 
> > Warning can always be seen during kdump kernel boot on qemu/kvm
> > platform. Our customer even saw casual kdump kernel hang once in
> > ~30 attempts during stress testing of kdump on KVM machine.
> > 
> > v4->v5:
> >   Take out the change related to KEXEC_JUMP to a new patch 0002
> >   according to Eric's suggestion.
> >   Patch 0003 in this series only includes the regression fix.
> > 
> > v3->v4:
> >   Eric pointed out that in patch 0002 the change related to
> >   KEXEC_JUMP is not right.
> >   Correct it.
> > 
> >   Add Fixes tag and Cc to stable.
> 
> Eric, are these patches looking good to you now?

Thanks for checking this!

I got warning message from kbuild test robot on previous v3 and v4. I
guess this v5 post also has the issue since the code is the same, just
patch format is changed.

Will report status after investigation.

Thanks
Baoquan