Re: 2.6.13-rc3-mm3

["Martin J. Bligh" <mbligh@mbligh.org>]

>> > - There's a pretty large x86_64 update here which naughty maintainer wants
>> >   in 2.6.13.  Extra testing, please.
>> 
>> Is still regressed as of 2.6.12 for me, at least. Crashes in TSC sync.
>> Talked to Andi about it at OLS, but then drank too much to remember the
>> conclusion ... however, it's still broken ;-)
>> 
>> Matrix is here (see left hand column).
>> 
>> http://test.kernel.org/
>> 
>> Example boot log is here:
>> 
>> http://test.kernel.org/9447/debug/console.log
> 
> Does Eric's recent fix fix it?
> 
> 
> From: Eric W. Biederman <ebiederm@xmission.com>
> 
> sync_tsc was using smp_call_function to ask the boot processor to report
> it's tsc value.  smp_call_function performs an IPI_send_allbutself which is
> a broadcast ipi.  There is a window during processor startup during which
> the target cpu has started and before it has initialized it's interrupt
> vectors so it can properly process an interrupt.  Receveing an interrupt
> during that window will triple fault the cpu and do other nasty things.

Wheeeeeeee! that does indeed seem to work. Nice job. 

> I believe this patch suffers from apicid versus logical cpu number
> confusion.  I copied the basic logic from smp_send_reschedule and I can't
> find where that translates from the logical cpuid to apicid.  So it isn't
> quite correct yet.  It should be close enough that it shouldn't be too hard
> to finish it up.
> 
> More bug fixes after I have slept but I figured I needed to get this
> one out for review.

Eric, when you have a final version, throw it over to me, and I'll give
that one a spin-test too ...

Thanks!

M.
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