Panic when trying to netboot domU.

[Anders Magnusson <ragge%ltu.se@localhost>]

I have just tried to boot a domU from a fresh NetBSD 4 installation with 
xen 3.1.
But; it panics during startup:

file system (default generic): nfs
root on xennet0
nfs_boot: trying DHCP/BOOTP
unknown type console at xenbus0 id 0 not configured
nfs_boot: DHCP next-server: 10.0.0.1
nfs_boot: my_name=tor.sunet.se
nfs_boot: my_domain=sunet.se
nfs_boot: my_addr=10.0.0.2
nfs_boot: my_mask=255.255.255.0
nfs_boot: gateway=10.0.0.1
panic: m_copydata: m == NULL, len 32
Stopped at      netbsd:cpu_Debugger+0x4:        popl    %ebp
db> bt
cpu_Debugger(c0413b5b,c054c654,1000000,40300ff,2) at netbsd:cpu_Debugger+0x4
panic(c04107cf,20,36,c01304dc,c0c00900) at netbsd:panic+0x155
m_copydata(c0c00b00,0,56,c0c00b38,0) at netbsd:m_copydata+0xbf
xennet_softstart(c0dad000,0,d63ac0,1,c010080b) at 
netbsd:xennet_softstart+0x2f3
softintr_dispatch(1,0,c0d63ac0,1,0) at netbsd:softintr_dispatch+0x61
DDB lost frame for netbsd:Xsoftnet+0x77, trying 0xc054c720
Xsoftnet() at netbsd:Xsoftnet+0x77
--- interrupt ---
0:


I run dhcpd on dom0 on a physical interface (bnx1) with bridge attached.

How do I debug this?  I would like to tcpdump, but that won't work so 
well on bnx1. 

-- Ragge