Kernel updates without rebooting

KSplice was a novel piece of code and nothing similar has been written for Linux. While it possible (and probable) that somebody can fork the old open source code and continue development, there are presently no alternative pieces of software in distribution for hot patching a running Linux kernel.

kexec is a nice way of doing fast reboot. While this isn't 'live upgrading your kernel', it does some interesting things such as bypassing BIOS, POST and BootLoader...

Some additional informations can be found through Ubuntu 'RapidReboot' topic : https://wiki.ubuntu.com/RapidReboot