Backport my recent fix (rev. 2.40 of Python/pystate.c):

Fix:

[ 1176893 ] Readline segfault

by unsilly-ing PyGILState_Release().

Backport candidate.

Misc/NEWS

@@ -12,6 +12,12 @@ What's New in Python 2.4.2a
 Core and builtins
 -----------------
 
+- It is now safe to call PyGILState_Release() before
+  PyEval_InitThreads() (note that if there is reason to believe there
+  are multiple threads around you still must call PyEval_InitThreads()
+  before using the Python API; this fix is for extension modules that
+  have no way of knowing if Python is multi-threaded yet).
+
 - Typing Ctrl-C whilst raw_input() was waiting in a build with threads
   disabled caused a crash.
 

Python/pystate.c

@@ -503,6 +503,6 @@ PyGILState_Release(PyGILState_STATE oldstate)
 	}
 	/* Release the lock if necessary */
 	else if (oldstate == PyGILState_UNLOCKED)
-		PyEval_ReleaseThread(tcur);
+		PyEval_SaveThread();
 }
 #endif /* WITH_THREAD */