Failed to initialize NVML: Driver/library version mismatch

As @etal said, rebooting can solve this problem, but I think a procedure without rebooting will help.

For Chinese, check my blog -> 中文版

The error message

NVML: Driver/library version mismatch

tell us the Nvidia driver kernel module (kmod) have a wrong version, so we should unload this driver, and then load the correct version of kmod

How to do that ?

First, we should know which drivers are loaded.

lsmod | grep nvidia

you may get

nvidia_uvm            634880  8
nvidia_drm             53248  0
nvidia_modeset        790528  1 nvidia_drm
nvidia              12312576  86 nvidia_modeset,nvidia_uvm

our final goal is to unload nvidia mod, so we should unload the module depend on nvidia

sudo rmmod nvidia_drm
sudo rmmod nvidia_modeset
sudo rmmod nvidia_uvm

then, unload nvidia

sudo rmmod nvidia

Troubleshooting

if you get an error like rmmod: ERROR: Module nvidia is in use, which indicates that the kernel module is in use, you should kill the process that using the kmod:

sudo lsof /dev/nvidia*

and then kill those process, then continue to unload the kmods

Test

confirm you successfully unload those kmods

lsmod | grep nvidia

you should get nothing, then confirm you can load the correct driver

nvidia-smi

you should get the correct output