Hi Nick, I tried that today, and it made no difference. The race condition is between udevd and systemd-fsck not systemd-fsckd, I think. systemd-fsck starts util-linux fsck that had the change in how it uses flock that makes its lock independent from that of udevd. But perhaps that's not what you were getting at by suggesting this test. Just trying to eliminate the idea of systemd-fsckd coming into play, maybe?
Test: I followed the same steps as before. Starting with a new 24.04 install, I set the grub timeout to zero, added and enabled my service that reboots unless something fails to mount, and, this time, ran your command to mask systemd-fsckd, the socket and the service. Then I rebooted. I got a mount failure after 10 minutes or so of constant rebooting. That it happend this quickly may be by chance. More often it takes an hour or two, but I've had a short test run before too. $ grep -n -H timeout /boot/grub/grub.cfg /boot/grub/grub.cfg:20:set timeout=0 $ cat /etc/systemd/system/reboot-when-good.service [Unit] Description=Reboot if no mounts fail SuccessAction=reboot DefaultDependencies=no Requires=local-fs.target After=local-fs.target # systemctl enable reboot-when-good.service Created symlink /etc/systemd/system/sysinit.target.wants/reboot-when-good.service → /etc/systemd/system/reboot-when-good.service. $ grep -n -FH VERSION /etc/os-release /etc/os-release:3:VERSION_ID="24.04" /etc/os-release:4:VERSION="24.04.3 LTS (Noble Numbat)" /etc/os-release:5:VERSION_CODENAME=noble /scp:qvm: # systemctl mask systemd-fsckd.socket systemd-fsckd.service Created symlink /etc/systemd/system/systemd-fsckd.socket → /dev/null. Created symlink /etc/systemd/system/systemd-fsckd.service → /dev/null. Result: sdb3 / cache2 didn't mount More detailed test results attached as test-results-fsckd- masked.2026-08-27. Full journalctl -b output attached (with some strings renamed for anonymity) as jctl-fsckd-masked.2026-08-27.lz. ** Attachment added: "More detail on the mount failure, systemd-fsck masked" https://bugs.launchpad.net/ubuntu/+source/util-linux/+bug/2160558/+attachment/5996014/+files/test-results-fsckd-masked.2026-08-27 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2160558 Title: udevd and fsck contend causing the prior to miss fs uuids To manage notifications about this bug go to: https://bugs.launchpad.net/util-linux-ng/+bug/2160558/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
