Is there a downside to ksplice? `ksplice` is an open source extension of the Linux kernel which allows system administrators to apply security patches to a running kernel without having to reboot the operating system. (From Wikipedia.) Is there a downside to using ksplice? Does it introduce any kind of instability? If not, why is it not included by default in more Linux distributions?

Technically it's very sound, I think that the fact distributions do provide this method of patching yet is:

* It does not integrate with the existing update methods (packaging wise)

* It adds to the burden of the distro to provide another method of upgrading.