Most likely, the problem is not the socket module but how you call Python code from a thread that was started from C/C++. Look at t_bootstrap() in threadmodule.c for an example on what to do. (And yes, it's tricky.) There should also be something in the Python/C API documentation about this.

I'm not closing the bug report since this is really a documentation issue; it needs to be documented better. I'll assign it to Fred.