+++ This bug was initially created as a clone of Bug #171809 +++ Because bug 171809 has been already closed, I have opened the new one. Bug 404911, bug 384221 and bug 408341 may dup. of this bug. When I use pymol program (sorry, it's not a fedora-released package), the following error occurs. python: Modules/gcmodule.c:276: visit_decref: Assertion `gc->gc.gc_refs != 0' failed. And we can get the same error by using other python-based programs. The same program works fine if I use home-made python-2.5.2 without applying any patch in Fedora package. So I believe this is a Fedora-specific python bug.
Created attachment 310665 [details] gdb output
As you can see with the other bugs, these types of things are assumed to be pretty much never python GC bugs (or _lots_ of people would be hitting them). If you have a shared object that is being loaded into python, esp. if it's "unusual" I'd look there first. After that, you can try running under valgrind (you need the valgrind changes) as it's _possible_ some core python .so is doing something bad under a weird condition ... but I'll note that I've never seen that yet.
Oops, The bug has been fixed in the latest trunk of pymol by adding "Py_XINCREF". Sorry for bugspam.