We Have Already Seen Patents in Linux Distros (Score 3, Informative)

FSMLabs has a patent on running Linux as a thread within a real-time operating system that is used in their RTLinux distribution. If you develop a real-time module under the GPL, you are automatically covered by their patent license. If you want to release a real-time module under a different license than the GPL, you need to get a commercial patent license from FSMLabs.

In this usenet posting Linus states that neither he nor the FSF have a problem with the FSMLabs patent.