@newt The CDDL is a free software license, but it is intentionally GPLv2-incomptable; https://www.gnu.org/licenses/license-list.html#CDDL

Linux developers use some retarded method where they use EXPORT_MODULE("GPL") (i.e. any version of the GPL) to mean that "this module is under the GPLv2 (who knows if it's -only or -or-later) and we feel like utilizing such module's interface makes a derivative work", even though the whole of Linux should be GPLv2 as there is a massive chain of derivative works resulting from its custom interfaces and the concept of a "non-GPLv2" module makes no sense.

The derivative work status carries through any "wrapper module" no matter what games you play and writing a "wrapper module" indicates wilful copyright infringement as the infringee has understood what is required and has tried to get around that.

If Linus wasn't completely spineless, he would respond to such infringement of his copyright by withdrawing his license permanently and noting that he would be seeking maximal damages for any further copyright infringement, but he won't.