This is still happening, and it feels like a race. I've enabled debug logging and captured the journal from good and bad boots. Comparing them hasn't told me a whole lot; on the whole the udev debug logging isn't very applicable. I do see that in both cases udev starts up and reads the exact same set of rule files, and the statistics it prints about the rule files are identical. Both have read in /lib/udev/rules.d/99-systemd.rules which contains the rule for adding the systemd tag. Nothing else has really stood out yet, but they are pretty difficult to compare.
I also find that if I run 'udevadm trigger -c add /sys/devices/pci0000:00/0000:00:1f.2/ata4/host3/target3:0:0/3:0:0:0/block/sda' from recovery mode that udev does add the systemd tag at that point. I'll attach my logs and udev databases from the good and bad boots. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to systemd in Ubuntu. https://bugs.launchpad.net/bugs/1625217 Title: udev sometimes doesn't apply systemd tag to devices Status in systemd package in Ubuntu: New Bug description: Since upgrading this machine to yakkety I've seen periodic hangs during booting. If I wait long enough systemd give up and drops to maintenance mode. Looking in the journal I see events like this: Sep 19 08:24:22 ubuntu-xps13 systemd[1]: dev-disk-by\x2duuid- 63cd6483\x2ddf95\x2d4426\x2d916e\x2d8c28becbfd8f.device: Job dev-disk- by\x2duuid- 63cd6483\x2ddf95\x2d4426\x2d916e\x2d8c28becbfd8f.device/start timed out. Searching on the internet indicates that this happen if devices reported by udev don't have the "systemd" tag, and I find that they do not have the tag when the boot times out but they do have the tag when boot does not time out. This happens once for every 3 or 4 boots and with both 4.4 and 4.8 kernels. I'm attaching the output of 'journalctl -xb' and 'udevadm info --export-db' from a timed-out boot. ProblemType: Bug DistroRelease: Ubuntu 16.10 Package: udev 231-6 ProcVersionSignature: Ubuntu 4.8.0-11.12-generic 4.8.0-rc6 Uname: Linux 4.8.0-11-generic x86_64 ApportVersion: 2.20.3-0ubuntu7 Architecture: amd64 CurrentDesktop: Unity Date: Mon Sep 19 09:27:08 2016 EcryptfsInUse: Yes InstallationDate: Installed on 2015-02-19 (577 days ago) InstallationMedia: Ubuntu 15.04 "Vivid Vervet" - Alpha amd64 (20150110) MachineType: Dell Inc. XPS 13 9343 ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.8.0-11-generic root=UUID=bdad03f3-06c0-439d-8869-32fad0b1851b ro quiet splash SourcePackage: systemd UpgradeStatus: Upgraded to yakkety on 2016-01-08 (254 days ago) dmi.bios.date: 05/15/2015 dmi.bios.vendor: Dell Inc. dmi.bios.version: A04 dmi.board.name: 0TM99H dmi.board.vendor: Dell Inc. dmi.board.version: A00 dmi.chassis.type: 9 dmi.chassis.vendor: Dell Inc. dmi.modalias: dmi:bvnDellInc.:bvrA04:bd05/15/2015:svnDellInc.:pnXPS139343:pvr01:rvnDellInc.:rn0TM99H:rvrA00:cvnDellInc.:ct9:cvr: dmi.product.name: XPS 13 9343 dmi.product.version: 01 dmi.sys.vendor: Dell Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1625217/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp