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Lock command on Linux running gdm results in a black screen and stuck state #22437

Open allenhouchins opened 1 month ago

allenhouchins commented 1 month ago

Fleet version: 4.57.0

Web browser and operating system: Chrome or Safari

💥  Actual behavior

If you have an Ubuntu 24.04 host running gdm as its desktop manager, sending a Lock command will put the device in an unusable state -- the screen goes black and takes no user input. Rebooting the device never gets you back to the login screen. You have to send an Unlock command and reboot again to regain functionality. If you switch your desktop manager to lightdm, the Lock and Unlock commands work as you would expect.

🧑‍💻  Steps to reproduce

  1. Set up a new Ubuntu 24.04 host running gdm as the desktop manager (this should be the default)
  2. Send a Lock command and observe behavior
  3. Send an Unlock command and reboot to get back to a working state
  4. Switch the desktop manager to lightdm and observe normal, expected behavior

🕯️ More info (optional)

Video demonstration

I was able to replicate this in Parallels, VMware Fusion, bare metal arm64, and bare metal amd64

This might be a bug for gdm and not Fleet but wanted to verify there wasn't a different approach we could take with gdm to prevent this behavior. This issue is not present in RHEL, Kali, or Fedora but I believe they do not use gdm.

georgekarrv commented 1 month ago

Thanks Allen, we will take a look here sometime next week

dantecatalfamo commented 1 week ago

Some initial research on this:

It appears to be related to a change made to GDM. I can replicate this behaviour by just creating the /etc/nologin and logging out. Removing the file and restarting GDM seems to fix it.

Previously GDM would show the login prompt as usual and throw an error when the user enters a password instead of coming up as a black screen alltogether.

I will continue to investigate.

dantecatalfamo commented 1 week ago

This bug appears to be Ubuntu only. It doesn't happen on the latest release of Fedora