We are developing an experimental web Framework using "solely" WebOb. We are handling concurrent requests and it's basically a quite simple integration of WebOb. We are hosting our application on webfaction.com
The thing is we have this Fatal Python Error that appears in our log:
Fatal Python error: XXX block stack underflow
There is no other traceback or information. and it makes our application crashes (it restarts automatically minutes later). We never had that problem in developpment.
EDIT: I've checked and my python application memory is way too high, it could be a related problem
The thing is, when I try to crossreference the Access log, there is nothing that corresponds to that access time.
As I said, there is no traceback or info on the error.
So, I first searched on what is a block stack underflow in Python and I found this very interesting article: http://tech.blog.aknin.name/2010/07/22/pythons-innards-interpreter-stacks/ which explains what is a block stack underflow.
EDIT:I also tried removing all the .pyc and restarting the server. No results
So, Here is my question: What could cause a block stack underflow in the compiler? What "type" of code could cause this?
First, try to remove all .pyc files (and .pyo if any), and restarting the server. If it doesn't help, please report the issue to http://bugs.python.org/ --- it really looks like a Python bug. The only way I can think of getting this would be by using obscure trickery like generating custom bytecode sequences.
If you cannot post a way for us to reproduce the problem, you can also try to edit Objects/frameobject.c in the Python source code, in PyFrame_BlockPop(), to display more information before the crash. At least _PyObject_Dump(f); _PyObject_Dump(f->f_code); would be useful in locating where the error is.