ubuntu 16.04 with wheezy nfs-root --> kernel panic

[sebastian at coli.uni-saarland.de]

Hi,
I tried the debian nfsroot now. But I'm still trying to get any working
solution with FAI and Ubuntu 16.04. I've now set up a wheezy box and
created a nfsroot there. This works without problems.

But when I boot with pxe I get a kernel panic in the function
put_nfs_open_context right after the networkinterface has been
configured.

My /etc/exports on the nfs-server is:

/srv/fai/config
RANGE/XY(fsid=1,ro,nohide,insecure,no_subtree_check,async) /srv/fai/nfsroot
RANGE/XY(fsid=2,ro,nohide,insecure,no_subtree_check,async,no_root_squash)


The kernel cmdline is (removing net.ifnames=0 biosdevname=0 has no
effect so this is not the culprit..):

append initrd=initrd.img-4.4.0-18-generic ip=dhcp net.ifnames=0
biosdevname=0 root=/dev/nfs nfsroot=IPOFFAISERVER:/srv/fai/nfsroot
boot=live  FAI_FLAGS=verbose,sshd,reboot FAI_ACTION=install


On the serverside I get a confirmation in the syslog when I boot the
client:

Apr 12 11:31:50 fai rpc.mountd[14180]: authenticated mount request from
CLIENTIP:791 for /srv/fai/nfsroot (/srv/fai/nfsroot)


Are my nfs-settings wrong? Any idea how to fix it?