I have the same problem.
When I boot the kernel "pve-kernel-4.13.8-2-pve", pvesm status hangs.
I could track it down to the external ceph storage.
With "pve-kernel-4.13.4-1-pve" everything works as expected. ceph is accessible.
With the new kernel, the command
/usr/bin/rados -p rbd <many...