In Fedora 21, systemd periodically reports in syslog: Dec 15 20:39:01 jik2 systemd: Failed to reset devices.list on /system.slice: Invalid argument It seems to periodically do this every minute for several minutes at a time, and then stop for a while. I have no idea what this means or whether it indicates a real issue I should be concerned about.
Fixed in git (714e2e1d56b97dcf2ebae2d0447b48f21e38a600).
systemd-216-16.fc21 has been submitted as an update for Fedora 21. https://admin.fedoraproject.org/updates/systemd-216-16.fc21
Package systemd-216-16.fc21: * should fix your issue, * was pushed to the Fedora 21 testing repository, * should be available at your local mirror within two days. Update it with: # su -c 'yum update --enablerepo=updates-testing systemd-216-16.fc21' as soon as you are able to. Please go to the following url: https://admin.fedoraproject.org/updates/FEDORA-2015-0916/systemd-216-16.fc21 then log in and leave karma (feedback).
systemd-216-16.fc21 has been pushed to the Fedora 21 stable repository. If problems still persist, please make note of it in this bug report.