Using dhclient in a system running Oracle VM with a large number of PCIe cards installed can cause a system panic. In some system configurations, Oracle VM might not allocate sufficient resources for all option cards. When this happens, an option card driver might attempt to load with insufficient resources resulting in a system panic.
Workaround
Edit the grub.conf file to add the following kernel boot parameters:
extra_guest_irqs=64,2048 nr_irqs=2048