Panic on 11-STABLE with Xen guest

[Roger Pau Monné]

On Mon, Nov 26, 2018 at 10:31:43AM -0800, John Baldwin wrote:
> On 11/22/18 12:39 PM, Joe Clarke wrote:
> > I believe after the commit 340016 for the dynamic IRQ layout, my Xen VM
> > started to panic.  I just upgraded the kernel today and saw this:
> > 
> > xen: unable to map IRQ#2
> > panic: Unable to register interrupt override
> > cpuid = 0
> > KDB: stack backtrace:
> > #0 0xffffffff8060a4e7 at kdb_backtrace+0x67
> > #1 0xffffffff805c3787 at vpanic+0x177
> > #2 0xffffffff805c3603 at panic+0x43
> > #3 0xffffffff8093a766 at madt_parse_ints+0x96
> > #4 0xffffffff803353f9 at acpi_walk_subtables+0x29
> > #5 0xffffffff8093a5e6 at xenpv_register_pirqs+0x56
> > #6 0xffffffff80928296 at intr_init_sources+0x116
> > #7 0xffffffff8055eba8 at mi_startup+0x118
> > #8 0xffffffff8029902c at btext+0x2c
> > 
> > The following kernel works:
> > 
> > @(#)FreeBSD 11.2-STABLE #4: Thu Nov  1 02:24:07 EDT 2018
> > FreeBSD 11.2-STABLE #4: Thu Nov  1 02:24:07 EDT 2018
> >     root at creme-brulee:/usr/obj/usr/src/sys/CREME-BRULEE
> > 
> > The following kernel produces the panic above immediately on boot:
> > 
> > @(#)FreeBSD 11.2-STABLE #5: Wed Nov 21 11:08:38 EST 2018
> > FreeBSD 11.2-STABLE #5: Wed Nov 21 11:08:38 EST 2018
> >     root at creme-brulee:/usr/obj/usr/src/sys/CREME-BRULEE
> > 
> > Attached is a screen grab of the console of the panic.
> 
> Hmm, I don't see any obvious candidates of Xen changes that weren't included
> in the MFC.  I've added royger@ (who maintains Xen in FreeBSD) to the cc to
> see if he has an idea.
> 
> Roger, the main changes that aren't MFC'd to 11 from 12/head seem to be some
> refcounting on event channels and PVHv2 vs PVHv1?

Sorry, I seem to have missed the thread on stable@ and only replied to
the people that have CC'ed me. The issue is already fixed, see:

https://svnweb.freebsd.org/base?view=revision&revision=340982

Thanks, Roger.