When udev is restarted while pvscan processes (executed via --background or systemd-run) are running, those pvscan processes can get stuck waiting on udev sync later (but the udev they are waiting for no longer exists). Since we can't run pvscan “in the foreground” from udev perspective, we might need a workaround it pvscan to break off the wait if udevd dies for whatever reason. This happens often during initrd/rootfs transition at least in Arch Linux (https://bugs.archlinux.org/task/41833), but anything that causes a udev restart (like a system upgrade) is susceptible to the problem.
This bug appears to have been reported against 'rawhide' during the Fedora 22 development cycle. Changing version to '22'. More information and reason for this action is here: https://fedoraproject.org/wiki/Fedora_Program_Management/HouseKeeping/Fedora22
Fedora 22 changed to end-of-life (EOL) status on 2016-07-19. Fedora 22 is no longer maintained, which means that it will not receive any further security or bug fix updates. As a result we are closing this bug. If you can reproduce this bug against a currently maintained version of Fedora please feel free to reopen this bug against that version. If you are unable to reopen this bug, please file a new report against the current release. If you experience problems, please add a comment to this bug. Thank you for reporting this bug and we are sorry it could not be fixed.