gdm3 freezes then locks out user after upgrade from 16.04 to 18.04

[Damiön la Bagh]

Steps to reproduce
Upgrade from 16.04.5 to 18.04.1 LTS
login to gdm3
Use the desktop a bit and start Google Chrome
A notification from Chrome pops up and the entire desktop freezes
only the mouse work.
CTRL+ALT+F2 to open a TTY in order to try to recover
reboot the computer
Login with GDM3
black screen, quick blank then back to gdm3
again CTRL+ALT+F2
sudo apt install --reinstall lightdm
sudo reboot
GDM3 keeps starting, and keeps going to a black screen then back to login.
I'm marking this bug as a security vulnerability as the bug is denying access to the system.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: gdm3 3.28.2-0ubuntu1.4
ProcVersionSignature: Ubuntu 4.15.0-32.35-generic 4.15.18
Uname: Linux 4.15.0-32-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair nvidia_modeset nvidia
ApportVersion: 2.20.9-0ubuntu7.2
Architecture: amd64
Date: Wed Aug 15 22:30:46 2018
InstallationDate: Installed on 2015-11-15 (1003 days ago)
InstallationMedia: Ubuntu 14.04.3 LTS "Trusty Tahr" - Beta amd64 (20150805)
ProcEnviron:
 TERM=linux
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=nl_NL.UTF-8
 SHELL=/bin/bash
SourcePackage: gdm3
UpgradeStatus: Upgraded to bionic on 2018-08-15 (0 days ago)

[Seth Arnold (seth-arnold)]

Thanks for taking the time to report this bug and helping to make Ubuntu better. We appreciate the difficulties you are facing, but this appears to be a "regular" (non-security) bug. I have unmarked it as a security issue since this bug does not show evidence of allowing attackers to cross privilege boundaries nor directly cause loss of data/privacy. Please feel free to report any other bugs you may find.

[Daniel van Vugt (vanvugt)]

After reproducing the problem, reboot, log into a VT and please:

1. Run:
    journalctl -b-1 > previous_boot.log
   and send us previous_boot.log

2. Look in /var/crash for crash files. If you find any then please run:
    ubuntu-bug YOURFILE.crash
   on each. Then tell us here what they were named and what the new bug IDs (if any) are.

[Damiön la Bagh (kat-amsterdam)]

Here is a copy of journalctl -b-1 > Previous_Boot.log

[Damiön la Bagh (kat-amsterdam)]

The name of the crash file is

_usr_bin_gnome-shell.1000.crash

I uploaded it with ubuntu-bug
How do I see the bug number it created?

[Daniel van Vugt (vanvugt)]

The terminal window in which you ran ubuntu-bug will tell you the bug ID. If you've lost that then try looking at https://errors.ubuntu.com/user/ID where ID is the contents of /var/lib/whoopsie/whoopsie-id

That all said, your previous_boot.log mentions:

aug 15 23:38:55 poema whoopsie[5963]: [23:38:55] Parsing /var/crash/_usr_bin_gnome-shell.1000.crash.
aug 15 23:38:55 poema whoopsie[5963]: [23:38:55] Uploading /var/crash/_usr_bin_gnome-shell.1000.crash.
aug 15 23:38:56 poema whoopsie[5963]: [23:38:56] Sent; server replied with: No error
aug 15 23:38:56 poema whoopsie[5963]: [23:38:56] Response code: 200
aug 15 23:38:56 poema whoopsie[5963]: [23:38:56] Reported OOPS ID 9c43cbd2-a0d3-11e8-a8b5-fa163e192766

which I have now tracked down on our servers... It is bug 1787512.

Next, please:

 1. Delete all the files in /var/crash.
 2. Wait for the problem to happen again and report the gnome-shell crash again (hopefully).
 3. Tell us if you get directed to that same bug repeatedly, or if you can't tell then attach another 'journalctl -b-1' log.

[Daniel van Vugt (vanvugt)]

Tip: You might find removing gnome-shell extensions stops the crashes from happening :)

[Damiön la Bagh (kat-amsterdam)]

I only have the default Ubuntu gnome-shell extensions installed as installing extensions from some gnome website still seems to me to be an extreme IT Security risk.

I installed the gnome-tweak tool and lightdm the problem hasn't occurred anymore unless I try to log in with Wayland.

Wayland gnome-shell login still crashes back to the greeter at every boot.

Are you interested in the Wayland crashes?

[Damiön la Bagh (kat-amsterdam)]

Well gnome-shell crashed again and won't let me in again.

whoopsie 35M aug 19 20:51 _opt_minergate_minergate.1000.crash

I've attached a new previous boot

[Damiön la Bagh (kat-amsterdam)]

Wrong crash file, oops (blush)

I uploaded the gnome-shell one.

whoopsie 114M aug 19 20:52 _usr_bin_gnome-shell.1000.crash

[Daniel van Vugt (vanvugt)]

Please tell us the ID of the bug created by (or related to) that crash report.

If you can't find it then you can look for crash reports from the current boot by:

  journalctl -b | grep "OOPS ID"

or from the previous boot:

  journalctl -b-1 | grep "OOPS ID"

and tell us the new OOPS ID.

[Launchpad Janitor (janitor)]

[Expired for gdm3 (Ubuntu) because there has been no activity for 60 days.]