The developers knew of Linux but did not necessarily design with any intention of a port or plans in regard to the Linux VFS or kernel design. When it was a Solaris kernel feature, it was clearly not derived from Linux.<p>The modifications to make this driver to run on Linux caused a derivative work its original source (Solaris) and maybe of Linux itself. The 2003 thread implies that in such a case these modifications may not be derivative of Linux. That some kernel developers feel that the headers are factual and thus not copyrightable.<p>One could legally blackbox recreate the necessary header files and guarantee that their kernel module was not a derivative binary, so I  believe that creating a proprietary kernel module should be legal in principal.<p>On the matter of linking, the FSF claims that dynamic linking can violate the license, but this is constituted under their understanding of a &quot;derived work&quot;. Yet, the US code[1] clarifies that new copies and &quot;adaptations&quot; of a work do not constitute an infringement when created as an essential step in the utilization of the computer program[2]. The term &quot;adaptation&quot; is not defined but because this section is notwithstanding the author&#x27;s &quot;exclusive right... to prepare derivative works&quot; implies that &quot;adaptations&quot; and &quot;derivative works&quot;[3] are not equal. This would strengthen a position stating that no derivative works are created by simply running, linking, or loading applications.<p>[1] <a href="https:&#x2F;&#x2F;www.law.cornell.edu&#x2F;uscode&#x2F;text&#x2F;17&#x2F;chapter-1" rel="nofollow">https:&#x2F;&#x2F;www.law.cornell.edu&#x2F;uscode&#x2F;text&#x2F;17&#x2F;chapter-1</a> (read 101, 106, 117)
[2] <a href="https:&#x2F;&#x2F;www.law.cornell.edu&#x2F;uscode&#x2F;text&#x2F;17&#x2F;117" rel="nofollow">https:&#x2F;&#x2F;www.law.cornell.edu&#x2F;uscode&#x2F;text&#x2F;17&#x2F;117</a>
[3] <a href="https:&#x2F;&#x2F;www.law.cornell.edu&#x2F;uscode&#x2F;text&#x2F;17&#x2F;101" rel="nofollow">https:&#x2F;&#x2F;www.law.cornell.edu&#x2F;uscode&#x2F;text&#x2F;17&#x2F;101</a>