Entire X session crashes if the screensaver starts while notebook lid is closed

Submitted by leo..@..il.com

Assigned to Sean Davis @bluesabre

Link to original bug (#16528)

Description

Created attachment 9569 Logs with information of the crash

It was observed that xfce4-screensaver can cause a Xorg crash. This crash will make the entire Xorg session close, closing all applications and, due to how the computer is configured, will suspend the system.

Steps to reproduce:

1. Have xfce4-screensaver running. For now, I can reproduce this with the "pop art squares" screensaver (but may work with others);
2. Ensure the screensaver never started before in the current session;
3. Close the notebook's lid;
4. Wait the idle time when it should start;
5. Notice how, after that, Xorg has crashed and lightdm login screen appears, showing the user is not logged in.

This does not work 100% of the times. By the log messages, it may be related to the disabling of the screen when the lid is closed and xfce4-screensaver starting on what would be no screen, but then it crashes the session.

The steps that caused the crash are particularly noticeable on the xsession-errors log (it was attached with a few other relevant logs).

Relevant information:

xfce4-screensaver versions: 0.18-1 and git (af380858) Distribution: Xubuntu 20.04 Daily Kernel: 5.6-rc4 and 4.19.108 GPU: Intel HD Graphics 520 Xorg driver: intel

Attachment 9569, "Logs with information of the crash":
crash20201003095500.tar.xz

Version: 0.1.8