Re: Re: [PATCH] [BUGFIX] crash/ioapic: Prevent crash_kexec() from deadlocking of ioapic_lock

[Don Zickus <dzickus@redhat.com>]

On Thu, Aug 22, 2013 at 05:38:07PM +0900, Yoshihiro YUNOMAE wrote:
> >So, I agree with Eric, let's remove the disable_IO_APIC() stuff and keep
> >the code simpler.
> 
> Thank you for commenting about my patch.
> I didn't know you already have submitted the patches for this deadlock
> problem.
> 
> I can't answer definitively right now that no problems are induced by
> removing disable_IO_APIC(). However, my patch should be work well (and
> has already been merged to -tip tree). So how about taking my patch at
> first, and then discussing the removal of disabled_IO_APIC()?

It doesn't matter to me.  My orignal patch last year was similar to yours
until it was suggested that we were working around a problem which was we
shouldn't touch the IO_APIC code on panic.  Then I wrote the removal of
disable_IO_APIC patch and did lots of testing on it.  I don't think I have
seen any issues with it (just the removal of disabling the lapic stuff).

Regardless, your patch fixes a similar problem we saw on RHEL, so I am
happy either way.  The removal of the disable_IO_APIC() just makes the
code look cleaner.

Cheers,
Don