Re: EARLY_AP_STARTUP hangs during boot

On Mon, 16 May 2016 13:38:35 +0300
Konstantin Belousov <kostikbel_at_gmail.com> wrote:

> On Mon, May 16, 2016 at 12:27:31PM +0200, Gary Jennejohn wrote:
> > On Mon, 16 May 2016 12:22:42 +0200
> > Gary Jennejohn <gljennjohn_at_gmail.com> wrote:
> >   
> > > I tried out EARLY_AP_STARTUP, but the kernel hangs and I can't
> > > break into DDB.
> > > 
> > > I did a verbose boot and the last lines I see are related to routing
> > > MSI-X to various local APIC vectors.  I copied the last few lines and
> > > they look like this:
> > > 
> > > msi: routing MSI-X IRQ 256 to local APIC 2 vector 48
> > > msi: routing MSI-X IRQ 257 to local APIC 3 vector 48
> > > msi: routing MSI-X IRQ 258 to local APIC 4 vector 48
> > > msi: routing MSI-X IRQ 256 to local APIC 0 vector 49  
> > 
> > Oops, the the last line should read
> > msi: Assigning MSI-X IRQ 256 to local APIC 0 vector 49  
> You should be able to enter ddb at this point. Methods depend on the
> console used, serial break for serial console, ctrl-alt-esc for sc/vt
> AFAIR. If you have IPMI/DRAC/ILO, send nmi.
> 
> After getting at ddb> prompt, do 'bt' then 'ps' then 'alltrace' and
> show the output.

I tried ctrl-alt-esc, nothing happens.  Maybe because USB isn't
up yet.

Judging from the way the case fan starts ramping up it seems like
the CPU is in a tight loop.

-- 
Gary Jennejohn