After updating from 15.10 to 16.04, the passphrase prompt to decrypt my LVM disk is not presented when the boot splash screen is enabled. The bluish background is drawn and then the boot hangs indefinitely, waiting for the passphrase to be typed with no on-screen indication of such. Typing the passphrase and pressing enter continues to boot normally. Booting with 'nosplash' on the command line shows a text-mode passphrase prompt that works normally.
ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: cryptsetup 2:1.6.6-5ubuntu2
ProcVersionSignature: Ubuntu 4.4.0-21.37-generic 4.4.6
Uname: Linux 4.4.0-21-generic x86_64
ApportVersion: 2.20.1-0ubuntu2
Architecture: amd64
Date: Sun Apr 24 11:42:33 2016
InstallationDate: Installed on 2015-06-04 (324 days ago)
InstallationMedia: Lubuntu 15.04 "Vivid Vervet" - Release amd64 (20150422)
SourcePackage: cryptsetup
UpgradeStatus: Upgraded to xenial on 2016-04-22 (1 days ago)
crypttab: sda3_crypt UUID=ad243744-ddc3-4839-b492-5ede0ec8aecc none luks,discard
---
ApportVersion: 2.20.1-0ubuntu2
Architecture: amd64
DefaultPlymouth: /usr/share/plymouth/themes/lubuntu-logo/lubuntu-logo.plymouth
DistroRelease: Ubuntu 16.04
InstallationDate: Installed on 2015-06-04 (326 days ago)
InstallationMedia: Lubuntu 15.04 "Vivid Vervet" - Release amd64 (20150422)
MachineType: Dell Inc. XPS13 9333
Package: plymouth 0.9.2-3ubuntu13
PackageArchitecture: amd64
ProcCmdLine: BOOT_IMAGE=/vmlinuz-4.4.0-21-generic.efi.signed root=/dev/mapper/lubuntu--vg-root ro quiet splash vt.handoff=7
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.4.0-21-generic.efi.signed root=/dev/mapper/lubuntu--vg-root ro quiet splash vt.handoff=7
ProcVersionSignature: Ubuntu 4.4.0-21.37-generic 4.4.6
Tags: xenial
TextPlymouth: /usr/share/plymouth/themes/lubuntu-text/lubuntu-text.plymouth
Uname: Linux 4.4.0-21-generic x86_64
UpgradeStatus: Upgraded to xenial on 2016-04-22 (3 days ago)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
_MarkForUpload: True
dmi.bios.date: 11/07/2014
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A06
dmi.board.vendor: Dell Inc.
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.chassis.version: 0.1
dmi.modalias: dmi:bvnDellInc.:bvrA06:bd11/07/2014:svnDellInc.:pnXPS139333:pvr:rvnDellInc.:rn:rvr:cvnDellInc.:ct8:cvr0.1:
dmi.product.name: XPS13 9333
dmi.sys.vendor: Dell Inc.
Your crypttab contains:
sda3_crypt UUID=ad243744-
Your fstab does not list sda3_crypt, but it does list your root and home partitions as being on /dev/mapper/
Is lubuntu-vg a crypted VG? I.e., is your root partition encrypted - such as you would get if using the Ubuntu installer's "encrypt whole disk" option?
This is relevant for understanding where the bug lies, since different code paths are used to prompt for passphrases in the initramfs (root partition) vs. after boot (other partitions).
This bug is not reproducible for me here on Ubuntu 16.04.