The current Linux source code is always available in both a complete tarball (an archive created with the tar command) and an incremental patch from the official home ...
I recently installed Linux for the first time in over a year (at least I think it's been that long) since I got another machine to work with (my last died and couldn't afford to fix it). I started ...
It used to be that building the Linux kernel was not easy. Testing and debugging were even worse. Nowadays, it is reasonably easy to build a custom kernel and test or debug it using virtualization.