Re: [Bug #13116] Can't boot with nosmp

Stephen Hemminger
2009-06-09T20:58:46Z

On Tue, 09 Jun 2009 21:42:55 +0300
Avi Kivity <avi-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:

> Stephen Hemminger wrote:
>
>
>
> >> This only affects reboots. But yes, the cpumask code has bugs. Does
> >> the .config involved select MAXSMP?
> >>
> >>
> >
> > Patch does not fix the problem. Not sure if it is KVM only problem.
> > Look like possible cpumask always equals what ACPI / SMP tables report.
> > So currently looking into alloc_percpu which may not handle the possible
> > but never used cpus.
> >
> >
>
> Right, it shouldn't have.
>
> > It is x86-64 config and does not have MAXSMP set. It does have NR_CPUS set.
> >
>
> So it's not cpumask. Dare I suggest a bisect?
>

I did some testing of different versions.

* Problem does not exist with 2.6.30-rc8 (so regression should be closed).

* Problem does exist with 2.6.29.4

* Happens with both nosmp and maxcpus=1

Given that it is fixed in 2.6.30, at this point there really is no urgency
to spend more time investigating the issue. There are certainly bigger problems
to deal with.

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