I've just pushed a new udev package to ppa:vorlon/ppa which should provide better debugging capabilities. It unconditionally runs 'udevadm monitor -e' before starting udevd, and spits out the complete list of kernel/udev events after udevd is stopped in the initramfs - as well as spitting out a process list with 'ps -ef' so we can see what's been left behind that's still holding /dev open and preventing the mount -omove.
Anyone who's reproducing these boot failures (other than the LVM vgchange race case), please test with this updated package (~ppa3) and attach the full console output to the bug. If you can also attach the full console output to the bug from a successful boot, that will be useful for comparison. A few comments in summary about the things that have already been tried that didn't work: pkill after udevadm control --exit -- this was a distraction. The ps output I was looking at when I jumped to this conclusion was the output from running ps *before* running --exit, so it doesn't really tell us anything - especially since 'pkill udevd' vs 'udevadm control --exit' have nearly identical behavior, with the difference that udevadm is designed to wait for udevd to shut down before returning and the pkill call *may* catch processes that udevd has somehow managed to lose track of (a possible, but not likely, scenario). The new test package should tell us more, by showing us only those processes still running *after* udevadm is called. ps -ef not returning anything when run after the mount call (comment #75) - yes, because the initramfs script in question is 'set -e'; so as soon as the mount -omove call fails, the script terminates. We should grab the ps output before the mount call - this is done in the test package. non-empty /dev on the root filesystem - this will definitely mask the problem in many cases. For ease of reproducing the issue, best to do the following from the booted system: sudo mount -obind / /mnt sudo rm -rf /mnt/dev/* sudo umount /mnt thus ensuring /dev is empty and that any failure to move the /dev mount in the initramfs will be caught early. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/818177 Title: boot failures because 'udevadm exit' does not kill udevd worker threads To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-release-notes/+bug/818177/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
