i meet the same question,the error is:

AttributeError: module 'pointnet2._ext' has no attribute 'cylinder_query'

but after run python setup.py install ,the result is

Installed /home/yqyjin/.local/lib/python3.10/site-packages/pointnet2-0.0.0-py3.10-linux-x86_64.egg
Processing dependencies for pointnet2==0.0.0
Finished processing dependencies for pointnet2==0.0.0

and no error occured during the installation

i use ubuntu 22.04, python=3.10,cuda=12.8