If you are aware of a particular GPL violation, please report it to the project being violated. For the Linux kernel, that would be Software Freedom Conservancy, who recently announced a new strategy for achieving GPL compliance.

https://sfconservancy.org/copyleft-compliance/ https://sfconservancy.org/copyleft-compliance/enforcement-st... https://sfconservancy.org/copyleft-compliance/firmware-liber... https://sfconservancy.org/news/2020/oct/01/new-copyleft-stra...