Dom0 panics when linux DomU tries to access to virtual disk

[BERTRAND Joël <joel.bertrand%systella.fr@localhost>]

	Hello,

	I'm trying to install a Devuan linux in a DomU. I use Xen 4.13 and
NetBSD 9.1 as dom0.

Devuan.conf :
name = "Devuan"
memory = 4096
vcpus = 4
vif = [
    'mac=00:16:3E:6D:D1:01,bridge=bridge0'
]
disk = [
    '/vms/devuan_1.img,raw,xvda,rw',
    '/vms/devuan_beowulf_3.0.0_amd64-netinstall.iso,,hdc,cdrom'
]
vnclisten = "192.168.10.106"
keymap = "fr"
vnc = 1
type = "hvm"
firmware = "seabios"
boot = "d"

	DomU starts without any trouble, can access to network without
restriction, but when installer tries to write MBR and to format
partition (xdva1), dom0 crashes with a kernel panic. No trace in log and
server quickly reboots.

	Best regards,

	JKB