Is kmodsign necessary? I have been using the `sign-file` tool included in the linux-headers package. It is located at /usr/src/linux-headers-xxx/scripts/sign-file. It is also referenced by the script /etc/dkms/sign_helper.sh, included with the dkms package.
Regardless, something happened recently with dkms where it is no longer calling the sign tool script and there is no update on the current bug.