title: Segmentation fault with PyType_IsSubtype
body: <p>I'm getting the following error when debugging a C extension in gdb</p>
  
  <pre><code>Program received signal SIGSEGV, Segmentation fault.
  PyType_IsSubtype (a=0xc0089ca71d1afbb6, b=0x7fffed5441e0) at Objects/typeobject.c:1150
  1150    Objects/typeobject.c: No such file or directory.
          in Objects/typeobject.c
  </code></pre>
  
  <p>All I've found about it, so far, was a bug report regarding Python 3.4 in Debian 6.</p>
  
  <p>Using: Python 2.7.6/CentOS 6.6</p>