When you hotplug some option cards, it causes Linux to reset. These include InfiniBand and Sun Storage 16 Gb FC ExpressModule Universal HBA.
Workaround
Edit the grub config file:
For Oracle Linux 7, edit the file /boot/grub2/grub.cfg.
For Oracle Linux 6, edit the file /boot/grub/menu.lst.
Find the line that begins with linux16 /vmlinuz-3.8.13-68.1.2.el7uek.x86_64
Add the following to the end of this line: pci=pcie_bus_perf
Reboot your server.