XEN bpf panic

[Roy Marples <roy%marples.name@localhost>]

My -current ish XEN DOMU's randomly panic.
panic: kernel diagnostic assertion "!cpu_intr_p()" failed: file 
"/home/roy/src/src/sys/net/bpf.c", line 1581

https://nxr.netbsd.org/xref/src/sys/net/bpf.c#1581
KASSERT(!cpu_intr_p());

The rests of the trace looks like this (had to use addr2line)
xennet_softstart
/home/roy/src/src/sys/arch/xen/xen/if_xennet_xenbus.c:?
xennet_handler
/home/roy/src/src/sys/arch/xen/xen/if_xennet_xenbus.c:?
xen_intr_biglock_wrapper
??:?
evtchn_do_event
??:?
do_hypervisor_callback
??:?
hypervisor_callback

Is this enough information for some bright spark to fix?

Roy