On Thu, Nov 6, 2014, at 16:47, Sylvain BERTRAND wrote: > Linus T. does let closed source modules live (even so the GNU GPLv2 gives > legal > power to open the code, or block binary blob distribution, like what > happens > with mpeg video or 3D texture compression),
There's a significant amount of debate over what constitutes an 'arms length' interaction between two pieces of code and what makes them effectively a single piece of code. GNU takes the position that sharing the same address space in any way is the latter, and that normal interaction through files/pipes/sockets is the former (because it would be politically inconvenient for them to push too far) so long as it's not a specially defined protocol that only exists for that single pair of programs. The kernel people as far as I know take the position that sharing the same address space is okay so long as they only use certain approved APIs intended for use by modules - and that userspace-kernel interaction via normal system calls is always okay. None of this has been examined by a court.