On April 15, 2011 Google lost a suit brought by Bedrock Computer Technologies LLC which claimed it's patents were infringed upon. A Texas jury determined that the
patent infringements existed within the Linux kernel starting with the 2.4.22.x tree all the way to version "2.6.31.x, or versions beyond 2.6.31.x." You can find the details regarding the suit
here. This should affect not only Google's Android and related technologies but also any Linux distro utilizing those kernels!