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

[Eric W. Biederman]

Ingo Molnar <mingo@xxxxxxxxxx> writes:

> * Baoquan He <bhe@xxxxxxxxxx> 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?

The result of applying the patches looks good.
Barring whatever fix to header files that kbuild seems to find necessary.

I wish patches 1 2 and 4 were all the same patch.  That I think would
make reading the patches a bit easier, and make the backports clearer.
But at this point that is just me bike-shedding.

Reviewed-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>

Eric