console login loop after entering username followed by RETURN

Bug #1812095 reported by Thomas Schweikle on 2019-01-16
This bug affects 26 people
Affects Status Importance Assigned to Milestone
shadow (Ubuntu)

Bug Description

<hostname> login: <user>

Just do nothing. About two seconds later ...




After this being displayed three times:

"Too many failure" or so and login is restarting.

You cant login at all. Only solution: clear the password for the account you want to login with.

ProblemType: Bug
DistroRelease: Ubuntu 18.10
Package: login 1:4.5-1ubuntu1
ProcVersionSignature: Ubuntu 4.18.0-14.15-generic 4.18.20
Uname: Linux 4.18.0-14-generic x86_64
ApportVersion: 2.20.10-0ubuntu13.1
Architecture: amd64
CurrentDesktop: XFCE
Date: Wed Jan 16 19:34:30 2019
InstallationDate: Installed on 2011-10-19 (2645 days ago)
InstallationMedia: Xubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
SourcePackage: shadow
UpgradeStatus: Upgraded to cosmic on 2018-11-03 (74 days ago)

Thomas Schweikle (tps) wrote :
Thomas Schweikle (tps) wrote :

Setting the password again you'll have a login, but you cant type in your password. After typing your login name followed by RETURN password is immediately left. Looks like the entered RETURN is kept and all subsequent calls see RETURN and just quit.

Launchpad Janitor (janitor) wrote :

Status changed to 'Confirmed' because the bug affects multiple users.

Changed in shadow (Ubuntu):
status: New → Confirmed
Rob Mosher (rcmosher) wrote :

I'm experiencing the same issue. Here is the output from /var/log/auth.log after attempting to login:

Jan 30 17:52:39 computername login[3483]: pam_unix(login:auth): conversation failed
Jan 30 17:52:39 computername login[3483]: pam_unix(login:auth): auth could not identify password for [username]
Jan 30 17:52:42 computername login[3483]: FAILED LOGIN (1) on '/dev/tty2' FOR 'UNKNOWN', Authentication failure
Jan 30 17:52:42 computername login[3483]: pam_securetty(login:auth): cannot determine username
Jan 30 17:52:46 computername login[3483]: FAILED LOGIN (2) on '/dev/tty2' FOR 'UNKNOWN', Error in service module
Jan 30 17:52:46 computername login[3483]: pam_securetty(login:auth): cannot determine username
Jan 30 17:52:49 computername login[3483]: FAILED LOGIN (3) on '/dev/tty2' FOR 'UNKNOWN', Error in service module

Ulli Horlacher (framstag) wrote :

I have the same problem on all my hosts with Ubuntu 18.04 and kernels newer than 4.15.0-43:

I have servers without X11 and cannot login any more!
This is a severe crucial bug!!

Andrea (aturbiglio) wrote :

Ubuntu Mate 18.04.1, same problem with linux-image-4.15.0-44-generic and linux-image-4.15.0-45-generic

If I switch back to linux-image-4.15.0-43-generic I can succesfully login to TTY.

Rehan Khamaruddin (rsk02) wrote :

Ubuntu server here on a box that serves as NAS. I would have been toast had I not already setup SSH. Confirmed issue with both:


Florian (lokokoze) wrote :

I'm also unable to login to my machine anymore. I can confirm the issue for


I'm currently booting into linux-image-4.15.0-43-generic where the bug doesn't exist.

Using Ubuntu 18.04.1 server.

I'm have the same problem.
Not even the update to linux-image-4.15.0-45-generic solved this.

Like @lokkoze, I'm still using (choosing) linux-image-4.15.0-43-generic where the problem not exist

Kai-Heng Feng (kaihengfeng) wrote :

Backport of LP: #1813873 should solve this.

MrHobbit (buelens-paul) wrote :

I'm also having this exact same problem.
Using Ubuntu 18.04.1 Desktop, kernel linux-image-4.15.0-45-generic.
Kernel linux-image-4.15.0-44-generic has the same problem.
I do not have any older kernel installed to test.
Login via ssh or via a terminal in the gnome gui works.
Login via Alt-Ctrl-Fx or when booted in runlevel 3 fails as described in the other posts.

Ulli Horlacher (framstag) wrote :

Workaround for hosts with a physical secure console (as long as there is no fixed kernel):

Add to /etc/rc.local:

# root rescue shell on [Alt] [F9]
setsid /sbin/agetty -a root --noclear tty9 &

Rehan Khamaruddin (rsk02) wrote :

I just installed 4.18.0-14-generic using the package linux-image-generic-hwe-18.04. Same behavior as before. Still can't login through console.

Rehan Khamaruddin (rsk02) wrote :
bygorka (bygorka) wrote :

I have the same problem of the enter in the password field send many enters.

It happens to me in ubuntu 16.04.5 - 4.4.0-142

Tested that in 4.4.0-141 don't happen.

Also commented in this issue:
(the one that current issue is marked as duplicated of)
that kernel 4.4.0-143 has a fix for this.

I tested the kernel 4.4.0-143, and i can't reproduce the issue, so looks like fixed.

Lars Behrens (lars-behrens-u) wrote :

Confirmed Bug for 18.04.2 with Kernel 4.15.0-45-generic

Bug confirmed in Ubuntu 18.04.2 LTS with 4.15.0-45-generic kernel

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