Seriously, it is one of the biggest open-source C codebases out there, with thousands of hackers working on it. And the result is very good, as the majority of the internet is running on it.
I don't argue that linux itself is bad, it's obviously very good overall. That doesn't say anything about overall code quality though - as usual there are good, bad and really ugly parts.
"I've looked at the source and there are pieces that are good and pieces that are not. A whole bunch of random people have contributed to this source, and the quality varies drastically." -Ken Thompson
Seriously, it is one of the biggest open-source C codebases out there, with thousands of hackers working on it. And the result is very good, as the majority of the internet is running on it.