What causes a Python segmentation fault?

This happens when a python extension (written in C) tries to access a memory beyond reach.

You can trace it in following ways.

• Add sys.settrace at the very first line of the code.

• Use gdb as described by Mark in this answer.. At the command prompt

  gdb python
  (gdb) run /path/to/script.py
  ## wait for segfault ##
  (gdb) backtrace
  ## stack trace of the c code