[1] https://en.wikipedia.org/wiki/BSD_licenses#2-clause_license_...
[1] https://en.wikipedia.org/wiki/BSD_licenses#2-clause_license_...
Assuming that FreeBSD's maintainers want to keep their code under the BSD license, they'll be wanting something more permissive than the FSF's "heads I win tails you lose" version of compatibility.
Am I missing something about the BSD kernel licensing social dynamic?
Now if you changed your hypothetical so that it's not a patch but a separate module that compiles to its own distinct binary, and your hypothetical license were expanded to include a second clause, "Anything that links to binaries built from this code must inherit this license," then we'd be talking about a situation that replicates the issues with making use of GPL code in projects that use more permissive licenses.