| The argument goes along the lines that GPL-only symbols are so tightly coupled with the internals of the Kernel that by using them you are forming a derivative work of the Kernel, as opposed to just using interfaces in the same manner (legally-speaking) as a userspace program. Producing and distributing a module that uses these symbols under a non-GPL compatible license is already an infringement, because you have produced a derivative work and distributed it outside the license conditions. If you recompile your Kernel to remove the restriction then you may be aiding the module developer in committing a copyright violation. I’m not sure how much I buy this argument personally, but I have seen it advanced (I think on the LKML). UPDATE: I found it: https://lwn.net/Articles/154603/ Quoting Linus: > I think both them [the lawyers Linus claims he spoke to] said that anybody who were to change a xyz_GPL to the non-GPL one in order to use it with a non-GPL module would almost immediately fall under the "willful infringement" thing, and that it would make it MUCH easier to get triple damages and/or injunctions, since they clearly knew about it. Again, not endorsing this argument, just pointing out that some people (e.g. Linus) claim this isn’t permitted. I’m not entirely sure why people think this comment is worth downvoting: I have been very clear that I don’t really buy this argument, but I thought it was interesting and relevant to point out Linus’s take on the matter. |
Which in the case of ZFS is obviously nonsense. ZFS was developed on Solaris and ported to many other OSes. Its certainly not a derivative work of the linux kernel. This is a case of the linux kernel devs being bullies, and trying to make life harder for 3rd party modules.
If they can claim copyright violation for using a GPL-only symbol which didn't used to be GPL-only, then I think ZFS devs can claim an antitrust violation for locking them out of the kernel. Both legal concepts are absurd..