Frequently Asked Questions

1. The ‘os-build’ branch doesn’t compile, what can I do?

The os-build branch is auto-updated daily from upstream. While upstream is pretty good about having code that compiles, occassionally issues pop up.

First, check the ark-latest branch to see if any critical patches were applied to temporarily resolve things.

Second, sometimes the problem is new and waiting 24-48 hours for a maintainer to resolve things will be expected.

Third, you can use a release tag (ie kernel-5.14.1-0), if you do not need bleeding edge.

2. The ‘os-build’ branch doesn’t pass ‘make dist-configs’?

During the -rc1 and -rc2 phase, this is not uncommon. Most configs should be autogenerated to defaults and placed in pending-rhel until an official review has taken place.

Occassionally during the review cycle, the default changes and new configs are revealed that are not autogenerated and leads to unresolved configs.

Creating a file under redhat/configs/pending-rhel/ with the config settings necessary should temporarily resolve this until the maintainers can resolve this properly.

Please notify us on or file an issue at

3. I am booting an ELN/RHEL kernel on Fedora (or vice versa) and the kernel won’t boot. What do I do now?

This is not uncommon and may be due to a config difference between RHEL and Fedora. One key difference between the two kernels is that Fedora has enabled CONFIG_BTRFS where ELN/RHEL has not, and as a result ELN/RHEL kernels will not mount Fedora BTRFS filesystems. If you are booting the ELN/RHEL kernel config on Fedora you must change these configuration values in the .config:


If that change doesn’t resolve the boot failure, users should attempt to “flip” configs to determine the difference between the two flavors before reporting bugs. The maintainers acknowledge that this can be a time consuming process but it is left to the user to resolve config differences when cross booting between flavors.

4. How does an MR get reviewed?

Anything Fedora specific (configs, custom patches, scripts) will be decided by the Fedora kernel maintainer with input from the community.

Any patch that is cherry-picked from a commit in an upstream tree will be taken by the maintainer immediately with the assumption the commit will be merged to Linus’s tree within a week.

Any patch that touches infrastructure (redhat/) will need review by Red Hat developers. Those developers are auto-added by webhooks to the MR. An approval from 1 developer is generally good enough.

Any patch that touches kernel code that is not going upstream will need reviews by Red Hat developers. Those developers are auto-added by webhooks to the MR. These patches must wrapped with “#ifndef CONFIG_RHEL_DIFFERENCES” if possible and be provided with a good reason why it is important to include despite upstream not taking it. An approval from all the assigned reviewers is necessary.

See for a more thorough discussion.

4. Can I use build services koji or brew?


make dist-srpm
koji build --scratch eln|rawhide <srpm>
# this target requires internal Red Hat network access and will always
# build against the latest RHEL major compose
make dist-brew