Comment 53 for bug 1364630

Same message here but somewhat different dmesg output.
I'm running 14.10 upgraded from 14.04, and nvidia binary driver 331.113

dmesg (excerpted):
...
init: plymouth-upstart-bridge main process (294) killed by TERM signal
  (the *only* mention of "plymouth")
... then much later...
Disabling lock debugging due to kernel taint
nvidia: module verification failed: signature and/or required key missing - tainting kernel
vgaarb: device changed decodes: PCI:0000:03:00.0,olddecodes=io+mem,decodes=none:owns=none
Initialized nvidia-drm 0.0.0 20130102 for 0000:03:00.0 on minor 0
NVRM: loading NVIDIA UNIX x86_64 Kernel Module 331.113 Mon Dec 1 21:08:13 PST 2014
input: HDA NVidia HDMI/DP,pcm=3 as /devices/pci0000:00/0000:00:07.0/0000:03:00.1/sound/card1/input12
input: HDA NVidia HDMI/DP,pcm=7 as /devices/pci0000:00/0000:00:07.0/0000:03:00.1/sound/card1/input13
floppy0: no floppy controllers found
work still pending
EXT4-fs (sda6): mounted filesystem with ordered data mode. Opts: (null)
init: Error while reading from descriptor: Broken pipe
init: failsafe main process (904) killed by TERM signal