If you browse the LKML (Linux Kernel Mailing List) for 5 minutes, you’ll probably see a bunch of microsoft.com email addresses, and it’s been that way for years. I understand why it bothers some people, but also Linus (and a couple others) approve everything that actually gets merged, whether it’s from a microsoft employee, or a redhat employee, or anyone else. Even if microsoft wanted to pay employees to submit patches that would hurt the kernel, the chance that they’d actually be approved is so low it wouldn’t be worth their time.