Debugging conda-python with gdb

Situation: conda env, python3.9, multiprocessing pool gets stuck

$ gdb python <pid>

Will give you C-level stack frames. Need CPython-level stack frames.

For that, we need python-dbg. Not provided by Conda AFAIK. But the system version works.

$ gdb /conda/python/with/stuck/process <pid>

> source /usr/share/gdb/auto-load/usr/bin/python3.9-gdb.py

> py-bt

> py-[up|down]

> py-locals

> py-list # (print code)

> py-print $var

Some gotchas about spawn vs fork here:

https://britishgeologicalsurvey.github.io/science/python-forking-vs-spawn/