I've reverted to an older kernel after discovering that OpenZFS does not have currently have DKMS packages for the latest 5.12 release of Fedora 33 after a yum update.

I used Koji with the search term Kernel to download and install the necessary dependencies to revert to the latest 5.11 kernel, rebooted into it, and rebuilt ZFS without issue.

But while removing packages from the newer kernel I found that only kernel-headers for 5.12.9-200 was still installed (kernel-headers-5.12.9-200.fc33.x86_64 specifically).

I then realized that the packages listed by Koji for the packages I'd selected for 5.11 did not include kernel-headers and I had neglected to revert this before rebuilding ZFS.

Everything appears to be running correctly but have I inadvertently put my system or ZFS into a dangerously undefined state as a result?

The packages annobin, boost-devel, perl-ExtUtils-CBuilder, and zfs all depend on kernel headers and I am most worried about zfs.

I plan to install the correct kernel headers and rebuild these packages but wanted to ask here first for advice.

Also, why is kernel-headers not listed on the Koji page for the selected kernel? Because headers do not always track with the actual kernel release, I had to manually locate the last release for 5.11 which was 5.11.20-200. I would have preferred if this information was linked directly by Koji with the other kernel packages as tracking it manually is subject to error.

1 Answer 1


Didn't you mistake kernel-headers for kernel-devel?

kernel-headers is a singleton, only one version can be installed. And you must have one if you ever intend to compile anything, as it is a requirement to glibc-devel, which is a requirement to gcc. It defines the userland/kernel interface in /usr/include. Try this command: rpm -ql kernel-headers

On the other hand, kernel-devel, like kernel, may have many versions installed, and is required to compile kernel modules, like dkmss and kmods. And the generated modules will only be able to run in a kernel with the very same version.

BTW, there's no need to have a ZFS dkms specific to any kernel. Different from kmod, dkms compile a new version for each kernel. In particular, due to compiler incompatibilities I could not upgrade my zfs utils and dkms for some after upgrading to fc34. I was lucky that these incompatibilities affected only the userland utilities, not kernel compiling (dkms), and I kept using the same dkms from fc33 for a long time. Usually I tend to follow ZFS master directly from github.

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