I know of one case where Red Hat countersued a patent troll over a GPL violation. It was a pretty good illustration of the "nuclear deterrent" effect that such

I know of one case where Red Hat countersued a patent troll over a GPL violation. It was a pretty good illustration of the "nuclear deterrent" effect that such litigation can have. I'm not aware of any cases where Red Hat has brought any original suits of this nature, but then again I probably wouldn't be even if they did exist.