Lets say you want to debug a python process that is either already running or crashing in native code. Pythons PDB is of no help here and you will have to use low-level GDB debugger. Fortunately, it comes with support for debugging high level python scripts.
However, while the actual python-gdb commands are nicely described here, that page lacks important details on how to get python-gdb in the first place. We are merely told that a python-gdb.py is needed.
On Ubuntu/ Debian, this file is included in the python3-dbg package:
sudo apt install python3.10-dbgInstalling that is sufficient, if you use the matching python3 package. You can go ahead and connect to some running python process via:
gdb -p <PID>
# verify that the script is loaded
(gdb) info auto-load
# get a python backtrace
(gdb) py-bt
Traceback (most recent call first):
File "/usr/lib/python3.10/selectors.py", line 416, in select
fd_event_list = self._selector.poll(timeout)
File "/usr/lib/python3.10/socketserver.py", line 232, in serve_forever
...In case Ubuntu is merely a host and you use coda, you can still use the host python-gdb.py – even if the python versions dont match. You will have to load the script manually though like:
(gdb) source /usr/share/gdb/auto-load/usr/bin/python3.10-gdb.py