No reboot patching comes to Linux 4.0
With Linux 4.0, you may never need to reboot your operating system again.
One reason to love Linux on your servers or in your data-center is that you so seldom needed to reboot it. True, critical patches require a reboot, but you could go months without rebooting. Now, with the latest changes to the Linux kernel you may be able to go years between reboots.
This is actually a feature that was available in Linux in 2009 thanks to a program called Ksplice. This program compares the original and patched kernels and then uses a customized kernel module to patch the new code into the running kernel. Each Ksplice-enabled kernel comes with a special set of flags for each function that will be patched. The Ksplice process then watches for a moment when the code for the function being patched isn't in use, and ta-da, the patch is made and your server runs on.
