from the the-GPL-is-open-to-interpretation dept.
Grsecurity® is an extensive security enhancement to the Linux kernel that defends against a wide range of security threats through intelligent access control, memory corruption-based exploit prevention, and a host of other system hardening that generally require no configuration. It has been actively developed and maintained for the past 14 years. Commercial support for grsecurity is available through Open Source Security, Inc.
In a big red block at the top of their home page is the following warning:
Important Notice Regarding Public Availability of Stable Patches
Due to continued violations by several companies in the embedded industry of grsecurity®'s trademark and registered copyrights, effective September 9th 2015 stable patches of grsecurity will be permanently unavailable to the general public. For more information, read the full announcement.
And I thought GRSecurity was based on the GPL'd work called "Linux". Guess I was wrong.