[Python-Dev] help debugging thread deadlocks (original) (raw)

Russ Cox rsc@plan9.bell-labs.com
Fri, 1 Mar 2002 22:52:42 -0500

If this should be in python-list, say so and I'll move, but python-dev seemed a better match.

I've got a python program that's hanging in PyThread_acquire_lock called from fast_cfunction, which I assume means the python program itself is calling the acquire method on a python-allocated (as opposed to C-allocated) lock. There are two threads and both are hung trying to acquire different locks. Unfortunately that's all I can tell from the stack trace. My python program allocates three locks using threading.RLock, and I can't find any other python code (in the standard modules), but the locks that are hanging are not those three locks. I looked in the standard module library code and can't find any that allocate locks. There are some locks allocated in the C interpreter, of course, but I don't see how those would be acquirable from python code.

Is there some function I can call from within acquire_lock or allocate_lock (from C) to dump a python stack trace to stdout or stderr?

Thanks. Russ