Linux kernel live debugging, how it's done and what tools are used?

Question

What are the most common and why not uncommon methods and tools used to do live debugging on the Linux kernel? I know that Linus for eg. is against this kind of debugging fo

Answer 1

According to the wiki, kgdb was merged into the kernel in 2.6.26 which is within the last few years. kgdb is a remote debugger, so you activate it in your kernel then you attach gdb to it somehow. I say somehow as there seems to be lots of options - see connecting gdb. Given that kgdb is now in the source tree, I'd say going forward this is what you want to be using.

So it looks like Linus gave in. However, I would emphasize his argument - you should know what you're doing and know the system well. This is kernel land. If anything goes wrong, you don't get segfault, you get anything from some obscure problem later on to the whole system coming down. Here be dragons. Proceed with care, you have been warned.