GDM locks up with 100% CPU usage when logging in


I am experiencing a strange problem with gdm ( and gdm only ). When I start up my computer and log in, the screen stays blank. Switching to another tty or force-restarting X ( Ctrl-Alt-Backspace ) do not work, only a hard reset. SSH-ing into that instance I see that it’s not entirely locked up, only that gdm takes up 100% of the CPU, and stracing the project reveals that it does a lot of sched_yield() calls and nothing else.

Workaround that I have found:

  • restarting X as soon as I get the login screen
  • switching to another tty and then back
  • removing splash=silent from the boot parameters
  • use another display manager, such as lightdm

Unfortunately, neither of those is a real solution, and I’d like to be able to log in with gdm without any workarounds. How can I do that?


nvidia-bug-report.log.gz (224 KB)

You have two GPUs in your system and running without an xorg.conf. Did you check if this happens also if you remove the second gpu? Then check what happens when you create an xorg.conf which enables just one gpu.

Thanks for the answer @generix. I solved the problem with minimal changes by adding a file named /etc/X11/xorg.conf.d/90-nvidia.conf with the following contents:

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BusID          "PCI:1:0:0"