Install of custom kernel fails after recent dkms update

[R T]

Release: Ubuntu 16.04.6 LTS (xenial)

Upgrading dkms from 2.2.0.3-2ubuntu11.6 to 2.2.0.3-2ubuntu11.7 (the "fix" for https://bugs.launchpad.net/ubuntu/+source/dkms/+bug/1827697) breaks installation of custom kernels again, as it undoes the fixes done for bug https://bugs.launchpad.net/ubuntu/+source/nvidia-common/+bug/292606 .

To be specific, during package install (either via dpkg or apt-get) I'm now getting the following error from /usr/sbin/update-grub-legacy-ec2 which is run from /etc/kernel/postinst.d/x-grub-legacy-ec2 (after running /etc/kernel/postinst.d/dkms):

20 Unsupported command "*" (full line was " * dkms: running auto installation service for kernel ...") received from confmodule.

The only solution I've found so far is to downgrade dkms to 2.2.0.3-2ubuntu11.6.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[ucb-cy (ucb-cy)]

New to the Ubuntu community & issue tracker so apologies if this comment should go elsewhere.

I am seeing the same behavior on Ubuntu 18.04.3 LTS (bionic) after following the procedure for compiling a new kernel at https://help.ubuntu.com/lts/installation-guide/amd64/ch08s06.html. The compile completes successfully but installation fails when running sudo dpkg -i ../linux-image...deb.

After adding "set -x" to /etc/kernel/postinst.d/x-grub-legacy-ec2 and /usr/sbin/update-grub-legacy-ec2, it looks like the /usr/sbin/update-grub-legacy-ec2 script is failing in the ucf_update_kernels function.

RET='20 Unsupported command "*" (full line was " * dkms: running auto installation service for kernel 4.15.18custom") received from confmodule.'

[ucb-cy (ucb-cy)]

It looks like this change may have been introduced in 24a559e439f57f7e727b6d9c3395e1c11624c230 (https://github.com/dell/dkms/commit/24a559e439f57f7e727b6d9c3395e1c11624c230#diff-20750e5e3ce7e64c5a40b2f488f75a50)

[ucb-cy (ucb-cy)]

Submitted an issue with upstream: https://github.com/dell/dkms/issues/113

[ucb-cy (ucb-cy)]

A workaround that worked for me is to replace the following line in /etc/kernel/postinst.d/dkms:
`exec /usr/lib/dkms/dkms_autoinstaller start $inst_kern`
with
`exec /usr/lib/dkms/dkms_autoinstaller start $inst_kern >&2`