You have completely ignored the "if the Linux copyright holders agree" condition repeated
several times across, at least, my comments.
It is entirely within the power of the copyright holders to define the licence used, including
adding their exceptions to the GPL, such as "incorporating CDDL code is ok". My understanding
is that the Linux licence has even been modified in the past, and unilaterally at that!
We could imagine otherwise, sure. We could also imagine Jonathan Schwartz as He-Man battling
it out with Linus as Skeletor over who is master of Greyskull*... (feel free to mentally
reverse the roles according to preference).
* NB: humour..