As it stands there are quite a few long standing issues with docker ps hanging.

#25993
#12606

and so on.

At the root one of the biggest issues is that if a single container is blocking, you can no longer iterate through the container list:

can reducePSContainer be made more robust so it can skip a container if it is locked for more than N seconds and prints out the name of the problem container.

This would make it significantly easier to debug this issue and isolate the underlying cause.