KDB panic with 2 vcpus

Hi..

I'm currently trying to setup FreeBSD 8-CURRENT as a para-virtualized
domU on XEN 3.3.0 (with gentoo dom0).

When I configure 2 CPU's (using vcpus=2) in the domU config file, I get
the following error during bootup:
==========================================================================
virt-001 template_8-CURRENT # xm create -c 00_template_8-CURRENT.XENconfig
Using config file "./00_template_8-CURRENT.XENconfig".
Started domain template_8-CURRENT
WARNING: loader(8) metadata is missing!
GDB: no debug ports present
KDB: debugger backends: ddb
KDB: current backend: ddb
Copyright (c) 1992-2009 The FreeBSD Project.
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
        The Regents of the University of California. All rights reserved.
FreeBSD is a registered trademark of The FreeBSD Foundation.
FreeBSD 8.0-CURRENT #0: Wed Jan 14 21:47:10 CET 2009
    root_at_template-8_CURRENT.localdomain:/usr/obj/usr/src/sys/freebsd8_XEN
WARNING: WITNESS option enabled, expect reduced performance.
Xen reported: 1600.056 MHz processor.
Timecounter "ixen" frequency 1000000000 Hz quality 0
CPU: AMD Athlon(tm) Processor (1600.06-MHz 686-class CPU)
  Origin = "AuthenticAMD"  Id = 0x662  Stepping = 2
  Features=0x383fbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,MMX,FXSR,SSE>
  AMD Features=0xc0480800<SYSCALL,MP,MMX+,3DNow!+,3DNow!>
real memory  = 268435456 (256 MB)
avail memory = 256045056 (244 MB)
gdtpfn=3e2d8 pdptpfn=28a43
FreeBSD/SMP: Multiprocessor System Detected: 2 CPUs
 cpu0 (BSP): APIC ID:  0
 cpu1 (AP): APIC ID:  1
cpu=0 irq=0 vector=0
cpu=0 irq=0 vector=1
cpu=1 irq=0 vector=0
cpu=1 irq=0 vector=1
kbd0 at kbdmux0
xenbus0: <Xen Devices> on motherboard
xc0: <Xen Console> on motherboard
Timecounters tick every 100.000 msec
xbd0: 5120MB <Virtual Block Device> at device/vbd/768 on xenbus0
xbd0: attaching as ad0
xn0: <Virtual Network Interface> at device/vif/0 on xenbus0
xn0: Ethernet address: 00:16:3e:11:4d:c4
GEOM: ad0s1: geometry does not match label (16h,63s != 255h,63s).
[XEN] netfront_backend_changed: newstate=2
[XEN] netfront_backend_changed: newstate=4
Spanic: blockable sleep lock (sleep mutex) XCONS LOCK _at_ /usr/src/sys/dev/xen/console/console.c:290
cpuid = 1
KDB: enter: panic
[thread pid 11 tid 100003 ]
Stopped at      kdb_enter+0x3a: movl    $0,kdb_why
db> 
=========================================================================

greetz
Mr. Olli