If I wanted to do Linux Kernel development, I'd apply at Red Hat. I've got a buddy who interviews newish kernel developers out of school for them - it doesn't sound like he's looking for anything super specific either - he's often dismayed at how new graduates he talks to aren't even up on source control or other things he considers fundamental. He's US based but the teams are international (though I don't know if they'd hire from any country; maybe just specific ones).
Anyway, that's where I'd apply.