Journal Journal: Patching the linux kernel without rebooting 1
I think, everyone from Linux industry, knows about kexec (fast rebooting
... actually not rebooting just switching kernels) or Pannus (live kernel patching, but right now the project is dead) and their use. The Linux community started very earlier to think at a method to switch or patch a live kernel, but this things should work only on a very good kernel with very good memory and process isolation ... but this was achieved some time ago, we have a very good and mature Linux kernel (in my opinion was perfect from 2.4.2x) what can run for years without a reboot (my record is 4 years on a system with kernel 2.6.8 and this kernel is far to be perfect).
Read the rest here.