> pf.o is somehow inherently incompatible with a XENU kernel, with or
> without DEBUG,DIAGNOSTIC.  I have a very similar panic when I load
> a standard pf.o into the kernel I use (see below).
> > > 
> > > Does anyone use kernel modules with Xen?
> 
> Yes. NetBSD 3.0/Xen 2.0. Both in Dom0 and DomU.  In this case the module
> is nnpfs_mod.o from the Arla (v. 0.41 and 0.43) AFS client.  I usually
> will use a custom xen kernel without DEBUG,DIAGNOSTIC so that the module
> will work with both a i386 and xen kernel.

The strange thing for me is that I was using pf.o with Xen for two weeks. 
It was definitely working as I was using it with spamd (and my logs showed 
spamd's usage).

I am using Xen through a hosting provider and they made some changes last 
week that made me lose service for approximately 15 hours. (They moved my 
service to a new server I think and I received new console IP.)

I never recorded what kernel I used before (and my logs with the details 
has already rotated). The Xen hosting provider told me that they made no 
changes to my kernel or modules. But the two times I attempted to use pf.o 
(modload -f of pf.o without the options and then using a pf.o with DEBUG 
and DIAGNOSTIC) I had kernel panics.