Re: EARLY_AP_STARTUP hangs during boot

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.

No crash dump is created.

Here some trace copied from the console:

Fatal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00
fault virtual address = 0x1818
fault code = supervisor write data, page not present
instruction pointer = 0x20:0xffffffff805492ef
[some stack trace]
taskgroup_adjust() at taskgroup_adjust+0x2f; frame 0xffffffff8196c90
mi_startup() at mi_startup+0x118; frame 0xffffffff8196fcb0

-- 
Gary Jennejohn