Installing Debian GNU/kFreeBSD in a VirtualBox yields Fatal trap 12: page fault while in kernel mode

[Ludovic Brenta <ludovic@ludovic-brenta.org>]

Hello,

I am trying to install kfreebsd-i386 using today's netboot installer
image, debian-testing-kfreebsd-i386-netinst.iso, in a virtualbox.

When I start the virtual machine, GRUB shows up, offering:
* Default install (using kernel of FreeBSD 10)
  Automated install  (using kernel of FreeBSD 10)
  Expert install (using kernel of FreeBSD 10)

  Boot from first hard disk

Any of the first three options (booting the kernel and the
debian-installer) gives:

kernel trap 12 with interrupts disabled

Fatal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00
fault virtual address   = 0xbff1e000
fault code              = supervisor write, page not present
instruction pointer     = 0x20:0xc0d59104
[...]

Did I do anything wrong?  I tried reducing memory from 4 GiB to 3 GiB
and the number of virtual processors to 1 and disabling PAE/NX but still
got the same results.  I could not find specific instructions for
installing kfreebsd-i386 in a VirtualBox.

(My hardware machine runs Debian amd64, testing; the processor supports
VT-x in case that's relevant; and I can run OS/2 in a VirtualBox).

-- 
Ludovic Brenta.