Licensing issue in ZFS when building kernel with CONFIG_DEBUG_LOCK_ALLOC

Question

When I build the mainline Ubuntu kernel (hirsute) with CONFIG_DEBUG_LOCK_ALLOC on, the build process fails giving the below error message

configure: error: Kernel built with CONFIG_DEBUG_LOCK_ALLOC which is incompatible with the CDDL license and will prevent the module linking stage from succeeding. You must rebuild your kernel without this option enabled.

Turns out ZFS builds with a CDDL license which is causing a problem. I don't require ZFS support, so is there a way wherein I can build my kernel without ZFS? Alternatively, DKMS fetches the ZFS deb file from the internet, so can I build ZFS locally (where I would change the license in the META file to GPL) and make the kernel use that instead of fetching the package from the internet.

I follow the steps given here to build my kernel.

Answer 1

The fix turned out to be pretty simple. I could turn off zfs support while building the kernel by flipping the do_zfs flag to false in the amd64.mk (There is one for each arch, so choose accordingly) file in kernel source.