Comment 69 for bug 802626

I believe I may have this issue after upgrade to 16.04.

- root=/dev/mapper/MyLV-Linux locks up and halts after "Begin: Running /scripts/local-top". Debugging described below makes me think this is actually inside /scripts/local-top/lvm2.
- Removing root= drops me into (initramfs) and lets me do some debugging.
- "lvm lvchange -ay --sysinit MyLV/Linux" locks up. (For this reason, I send it into background with &.)
- "kill -9" on the lvchange process + "dmsetup mknodes" results in functional and mountable devices appearing in /dev/mapper.
- "lvm lvchange -ay --noudevsync MyLV/Linux &" helps avoid the lockup.
- "lvm lvchange -ay -v -v -v --sysinit MyLV/Linux &" ends with, approx:
Udev cookie 0xsomething (semid 65538) decremented to 6
Udev cookie 0xsomething (semid 65538) waiting for zero
- "dmsetup udevcomplete_all" results in lvchange process being unblocked. However, no /dev/mapper devices are created.
- "/lib/systemd/systemd-udevd" is not running (though this may be due to init-bottom scripts having run already). Starting it does not make a difference either; the relevant cookie is still stuck at value '6'.

Does this sound relevant? Should I file a new bug?