Anyone who has copyrighted code in the kernel they're using can sue or a copyright holder can work with an organization like the EFF or Software Freedom Conserv

Anyone who has copyrighted code in the kernel they're using can sue or a copyright holder can work with an organization like the EFF or Software Freedom Conservancy to sue them. One of the big things with the Linux kernel is that it's GPLv2 and the GPLv2 doesn't offer an opportunity to come back into compliance. Any violation leads to an automatic termination to all rights. Most of the big kernel developers have said that they won't enforce GPLv2 "death penalty", but there's a lot of Linux developers out there and Linux doesn't have authors assign copyright so there's a huge number of copyright holders. > You may not copy, modify, sublicense, or distribute the Program except as expressly provided under this License. Any attempt otherwise to copy, modify, sublicense or distribute the Program is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance. There are lots of articles on this like http://www.fosspatents.com/2011/08/most-android-vendors-lost-their-linux.html http://www.fosspatents.com/2011/08/most-android-vendors-lost..., https://www.samba.org/samba/samba/ftp/slides/linuxcollab-why-samba-went-gplv3.pdf https://www.samba.org/samba/samba/ftp/slides/linuxcollab-why... Realistically, most of these things get settled or ignored and the world moves on with a bare minimum of enforcement.