At most 80% of Linux contributors have jobs at software companies. That doesn't mean that all of them are paid for their kernel development, but at least 20% of contributors are definitely not paid for it.
As for grsecurity, 100% of the core grsecurity team (that work at "Open Source Security") are paid for their work. I will admit that I'm not fully aware of the interactions between PaXTeam and grsecurity, but I'd be shocked to hear that nobody at PaXTeam works at a software company related to security or kernel hardening.
As for grsecurity, 100% of the core grsecurity team (that work at "Open Source Security") are paid for their work. I will admit that I'm not fully aware of the interactions between PaXTeam and grsecurity, but I'd be shocked to hear that nobody at PaXTeam works at a software company related to security or kernel hardening.