LP#1897491 "greeter hang with 100% CPU with black display"

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Reported first on Launchpad at https://bugs.launchpad.net/ubuntu/+source/lightdm-gtk-greeter/+bug/1897491

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LP#0: Steve Arnold (nerdboy) wrote on 2020-09-28:

Description: Ubuntu 20.04.1 LTS
Release: 20.04

lightdm-gtk-greeter:
Installed: 2.0.8-1ubuntu1
Candidate: 2.0.8-1ubuntu1
Version table:
*** 2.0.8-1ubuntu1 100
100 /var/lib/dpkg/status
2.0.6-0ubuntu1 500
500 http://ports.ubuntu.com focal/universe armhf Packages

Chromebook armv7 install of focal tarball, followed by manual upgrade and xubuntu-desktop install. Selecting lightdm display manager results in the above behavior. Switching to gdm3 does work, however, requiring a full gnome-desktop install seems to defeat the purpose of xubuntu-desktop.

The workarounds using Memlock in the service file for lightdm have no affect, and neither does a native arm package rebuild of 2.0.6. The one thing that does work (besides switching to gnome) is building the debian 2.0.8 package using ubuntu deb tarball. Otherwise all you get are the log errors shown below.

The greeter log shows the following:

** Message: 19:40:54.740: Starting lightdm-gtk-greeter 2.0.6 (Sep 18 2018, 01:17:10)

(process:5105): GLib-ERROR **: 19:40:54.851: creating thread 'gmain': Error creating thread: Resource temporarily unavailable
** Message: 19:51:32.569: Starting lightdm-gtk-greeter 2.0.6 (Sep 18 2018, 01:17:10)

(process:5597): GLib-ERROR **: 19:51:32.571: creating thread 'gmain': Error creating thread: Resource temporarily unavailable
** Message: 20:07:27.951: Starting lightdm-gtk-greeter 2.0.6 (Sep 18 2018, 01:17:10)

(process:6133): GLib-ERROR **: 20:07:27.954: creating thread 'gmain': Error creating thread: Resource temporarily unavailable
** Message: 20:09:14.102: Starting lightdm-gtk-greeter 2.0.6 (Sep 18 2018, 01:17:10)

(process:6244): GLib-ERROR **: 20:09:14.105: creating thread 'gmain': Error creating thread: Resource temporarily unavailable
** Message: 20:10:52.081: Starting lightdm-gtk-greeter 2.0.6 (Sep 18 2018, 01:17

[github-actions]

LP#1: Chris Guiver (guiverc) wrote on 2020-09-28:

Thank you for taking the time to report this bug and helping to make Ubuntu better. Please execute the following command only once, as it will automatically gather debugging information, in a terminal:

apport-collect 1897491

When reporting bugs in the future please use apport by using 'ubuntu-bug' and the name of the package affected. You can learn more about this functionality at https://wiki.ubuntu.com/ReportingBugs.

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LP#2: Steve Arnold (nerdboy) wrote on 2020-09-28:

apport information

Attachments:

• Dependencies.txt

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LP#3: Steve Arnold (nerdboy) wrote on 2020-09-28:

apport information

Attachments:

• ProcCpuinfoMinimal.txt

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LP#4: Steve Arnold (nerdboy) wrote on 2020-09-28:

apport information

Attachments:

• ProcEnviron.txt

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LP#5: Steve Arnold (nerdboy) wrote on 2020-09-28:

Sorry, if I follow these instructions:

"UnreportableReason: This is not an official Ubuntu package. Please remove any third party package and try again."

then it is impossible to login and do any of this stuff using the desktop. Is there some info I can collect manually via a console login?

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LP#6: Matinal Sun (matinal981922) wrote on 2020-12-28:

I have encountered this problem in the armhf board too. I employed Xubuntu 20.04 on both RK3399(aarch64) and RK3288(armhf). Then I found that the lightdm-greater cannot work in RK3288. The log is the same as Steve said. I attempted to avoid this problem by logging in automatically. It's a trick to use Xubuntu with a problematic greeter since it still goes to a black screen if I want to change users or reactiong. Do you find any solutions to resolve this problem?

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LP#7: Steve Arnold (nerdboy) wrote on 2021-01-11:

PING: can you just update your LTS package to 2.0.8 please? The current one is broken on armv7. Thanks.

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LP#8: Launchpad Janitor (janitor) wrote on 2021-11-24:

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