EARLY_AP_STARTUP hangs during boot

[Gary Jennejohn]

On Fri, 27 May 2016 09:50:05 +0200
Gary Jennejohn <gljennjohn at gmail.com> wrote:

> On Thu, 26 May 2016 16:54:35 -0700
> John Baldwin <jhb at freebsd.org> wrote:
> 
> > On Tuesday, May 17, 2016 06:47:41 PM Gary Jennejohn wrote:  
> > > On Mon, 16 May 2016 10:54:19 -0700
> > > John Baldwin <jhb at freebsd.org> wrote:
> > >     
> > > > On Monday, May 16, 2016 12:22:42 PM Gary Jennejohn 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    
> > >          ^^^^^^^ Assigning    
> > > > > 
> > > > > I tried disabling msi and msix in /boot/loader.conf, but the settings
> > > > > were ignored (probabaly too early).      
> > > > 
> > > > No, those settings are not too early.  However, the routing to different
> > > > CPUs now happens earlier than it used to.  What is the line before the
> > > > MSI lines?  You can take a picture with your phone/camera if that's simplest.
> > > >     
> > > 
> > > Here a few lines before the MSI routing happens:
> > > 
> > > hpet0: <High Precision Event Timer> iomem 0xfed00000-0xfed003ff irq 0,8 on acpi0
> > > hpet0: vendor 0x4353, rev 0x1, 14318180 Hz, 3 timers, legacy route
> > > hpet0: t0 : irqs 0x00c0ff (0), MSI, periodic
> > > hpet0: t1 : irqs 0x00c0ff (0), MSI, periodic
> > > hpet0: t2 : irqs 0x00c0ff (0), MSI, periodic
> > > Timecounter "HPET" frequency 14318180 Hz quality 950    
> > 
> > The assigning message means it is in the loop using
> > bus_bind_intr() to setup per-CPU timers.  Can you please try
> > setting 'hint.hpet.0.per_cpu=0' at the loader prompt to see if
> > disabling the use of per-CPU timers allows you to boot?
> >   
> 
> Something has changed since the last time I generated a kernel with
> this option.
> 
> Now I get a NULL-pointer dereference in the kernel, doesn't matter
> whether I set the hint or not.
> 

OK, now that the startup has been fixed, I tried setting the hint at
the loader prompt, but the kenel hangs in exactly the same place as
before.  I actually booted twice to make certain I hadn't made a
typo when setting the hint.

-- 
Gary Jennejohn