Systemd-sysext service is unable to start

I use systemd-sysext to run a couple of applications on Fedora 43 Silverblue. After Jan 7th/8th, systemd-sysext seems to have stopped working. When I run systemctl status systemd-sysext, I get:

× systemd-sysext.service - Merge System Extension Images into /usr/ and /opt/
     Loaded: loaded (/usr/lib/systemd/system/systemd-sysext.service; enabled; preset: enabled)
    Drop-In: /usr/lib/systemd/system/service.d
             └─10-timeout-abort.conf
     Active: failed (Result: exit-code) since Mon 2026-01-12 10:13:41 CST; 2h 19min ago
 Invocation: 5a3c84939aba4c81a554a5722b7238a1
       Docs: man:systemd-sysext.service(8)
    Process: 6897 ExecStart=systemd-sysext refresh (code=exited, status=1/FAILURE)
   Main PID: 6897 (code=exited, status=1/FAILURE)
   Mem peak: 3.2M
        CPU: 45ms

Jan 12 10:13:41 Legion-5 systemd[1]: Starting systemd-sysext.service - Merge System Extension Images into /usr/ and /opt/...
Jan 12 10:13:41 Legion-5 (sd-merge)[6910]: Using extensions 'tailscale.raw'.
Jan 12 10:13:41 Legion-5 (sd-merge)[6910]: Failed to mount sysext (type overlay) on /run/systemd/sysext/overlay/usr (MS_RDONLY|MS_NODEV "lowerdir=/run/systemd/sysext/meta/usr:/run/systemd/sysext/extensions/tailscale/usr:/usr"): Invalid argument
Jan 12 10:13:41 Legion-5 systemd-sysext[6897]: Failed to merge hierarchies
Jan 12 10:13:41 Legion-5 systemd[1]: systemd-sysext.service: Main process exited, code=exited, status=1/FAILURE
Jan 12 10:13:41 Legion-5 systemd[1]: systemd-sysext.service: Failed with result 'exit-code'.
Jan 12 10:13:41 Legion-5 systemd[1]: Failed to start systemd-sysext.service - Merge System Extension Images into /usr/ and /opt/.

I filed a bug report in the systemd-sysext repo but was directed here.

I also see this is dmesg’s output:

[  147.563481] overlayfs: maximum fs stacking depth exceeded

What can I do to fix this issue?

This is a kernel regression. See: kernel regression in the ostree.hotfix test · Issue #2087 · coreos/fedora-coreos-tracker · GitHub

2 Likes

https://bodhi.fedoraproject.org/updates/FEDORA-2026-1118e5854e landed in stable.