UPDATE: a previous version of this blog post claimed that systemd build systemd-257.7-r7 was affected by the issue. However, that build actually fixed it, and only systemd-257.7-r6 is affected.
Recent changes on edge and us transitioning to /usr-merge produced a critical bug on existing systems. The systemd build systemd-257.7-r6, available between 4th August and 5th August, falsely expects the mount command to be placed under /usr/bin, while it is in /bin, causing installations to hang in the next boot. systemd-257.7-r7 built on the 5th August contains a fix.
How do I know if I am affected?
Run:
apk list --installed systemd
If you see systemd-257.7-r6 in the output marked as [installed], and you have not run the /usr-merge manually, then you are affected. Do not reboot, and downgrade or upgrade to another version.
I am affected but have not yet rebooted
Please upgrade to the latest version, or if you do not have internet, try downgrading to a previous local version in your cache. If you can't downgrade or upgrade, you may try this band-aid around the issue, by running the following commands:
doas ln -s /bin/mount /usr/sbin/mount
doas mkinitfs
Please make sure to remove this bandaid after upgrade, this may interfere with system packages.
I already have a device that is hanging on boot
If you can't restore from a backup, we recommend join our main room on Matrix or IRC and ask for help.