Fix:

Michael W. Hudson · Michael W. Hudson · commit 774479c68bf6 · 2005-04-18T08:46:17.000Z
[ 1176893 ] Readline segfault

by unsilly-ing PyGILState_Release().

Backport candidate.
diff --git a/Misc/NEWS b/Misc/NEWS
@@ -12,6 +12,12 @@ What's New in Python 2.5 alpha 1?
 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.
 
diff --git a/Python/pystate.c b/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 */

Original file line number	Diff line number	Diff line change
`@@ -503,6 +503,6 @@ PyGILState_Release(PyGILState_STATE oldstate)`
`503`	`503`	`}`
`504`	`504`	`/* Release the lock if necessary */`
`505`	`505`	`else if (oldstate == PyGILState_UNLOCKED)`
`506`		`- PyEval_ReleaseThread(tcur);`
	`506`	`+ PyEval_SaveThread();`
`507`	`507`	`}`
`508`	`508`	`#endif /* WITH_THREAD */`