Segmentation fault: 11 python after upgrading to OS Big Sur

Ok. Just for anyone wondering

Just uninstalling and reinstalling the packages that were giving the error worked for me

pip uninstall matplotlib
pip install matplotlib

I had the same issue - a Python program that was working fine before updating to Big Sur, and crashing with:

Segmentation fault: 11

after updating.

As previous responses have advised, just uninstalling and reinstalling the offending Python libraries fixed the problem. For me, that meant matplotlib:

pip uninstall matplotlib 
pip install matplotlib 

Thank you!