Re: bug on shutdown from 68-mm4 (machine_power_off returning causes problems)

Eric W. Biederman (ebiederm@xmission.com)
12 May 2003 07:37:55 -0600


"Martin J. Bligh" <mbligh@aracnet.com> writes:

> >> Yup, backing out kexec fixes it.
> >
> >
> > Ok. Thinking it through the differences is that I have machine_power_off
> > call stop_apics (which is roughly equivalent to the old smp_send_stop).
>
> Mmmm. Not sure NUMA-Q will like disconnect_bsp_APIC() much, but I guess
> that's my problem, not yours ;-) I can't do init 6 at the moment, so I'm
> walking on thin ice as is ... if I have to fix a couple of things up for
> NUMA-Q, that's no problem.

Ah ok. This could explain some of your problems with kexec if you
can't even reboot the box....

> > In the kexec patch that does 2 things.
> > 1) It shuts down the secondary cpus, and returns the bootstrap cpu to
> > virtual wire mode.
> > 2) It calls set_cpus_allowed to force the reboot to be on the primary
> > cpu.
> >
> > After returning from machine_power_off. We run into a problem
> > in flush_tlb_mm. Because we have a cpu disabled, that is still part
> > of the mm's vm mask.
>
> OK ... I presume that's just because you shut down the secondaries then.
> If so ... shouldn't it remove them from the relevant vm mask when it
> offlines them? (probably not your code, but still)

Right. The code is more about shutting down the secondaries then off
lining them. In a general purpose scenario I expect more would need
to happen.

> > Does anyone know why machine_halt, and machine_power_off return?
>
> Nope, thats ... odd ;-)

That is what I thought.

I have sent the fixed patches to Andrew and CC'd the list so we will
see what develops.

Eric

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