"Module nvidia is in use" but there are no processes running on the GPU
I am trying to configure VirtualGL, and the configuration gives the following message:
IMPORTANT NOTE: Your system uses modprobe.d to set device permissions. You
must execute rmmod nvidia with the display manager stopped in order for the
new device permission settings to become effective.
When I try running rmmod nvidia (or with sudo), it says that module nvidia is in use:
rmmod: ERROR: Module nvidia is in use by: nvidia_uvm nvidia_modeset
I have already stopped my window manager by running sudo systemctl stop sddm.service, so when I check nvidia-smi it says that there are no processes running on the GPU.
Most of the threads I found on this issue are related to bumblebee, but I don't even have it insalled.
Output of nvidia-smi:
+-----------------------------------------------------------------------------+
| NVIDIA-SMI 430.40 Driver Version: 430.40 CUDA Version: 10.1 |
|-------------------------------+----------------------+----------------------+
| GPU Name Persistence-M| Bus-Id Disp.A | Volatile Uncorr. ECC |
| Fan Temp Perf Pwr:Usage/Cap| Memory-Usage | GPU-Util Compute M. |
|===============================+======================+======================|
| 0 GeForce GTX 1080 Off | 00000000:01:00.0 Off | N/A |
| 33% 39C P8 12W / 200W | 9MiB / 8119MiB | 0% Default |
+-------------------------------+----------------------+----------------------+
+-----------------------------------------------------------------------------+
| Processes: GPU Memory |
| GPU PID Type Process name Usage |
|=============================================================================|
| No running processes found |
+-----------------------------------------------------------------------------+
Ubuntu 18.04
Solution 1:
On Ubuntu 20.04, I've been able to fully unload and reload the NVIDIA modules with the following commands (performed via SSH or a text-only tty).
sudo service gdm3 stop
sudo rmmod nvidia_uvm
sudo rmmod nvidia_drm
sudo rmmod nvidia_modeset
sudo rmmod nvidia
# Then, reload them if desired:
sudo modprobe nvidia
sudo modprobe nvidia_modeset
sudo modprobe nvidia_drm
sudo modprobe nvidia_uvm
This came in handy e.g. when upgrading the NVIDIA driver without rebooting (which could happen unexpectedly via unattended apt upgrades).
As @Thomas pointed out in a comment, if there's still something preventing one of the modules from being unloaded, it's usually possible to figure out what with:
lsmod | grep nvidia
lsof | grep nvidia