From: Victor Stinner <victor.stinner@gmail.com>
Date: Fri, 13 Dec 2013 00:46:43 +0000 (+0100)
Subject: Close #19576: PyGILState_Ensure() now initializes threads. At startup, Python
X-Git-Tag: v3.4.0b2~246
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=62ca10051b5aa07b86807a50674dbef4cace22f7;p=thirdparty%2FPython%2Fcpython.git

Close #19576: PyGILState_Ensure() now initializes threads. At startup, Python
has no concrete GIL. If PyGILState_Ensure() is called from a new thread for the
first time and PyEval_InitThreads() was not called yet, a GIL needs to be
created.
---

diff --git a/Misc/NEWS b/Misc/NEWS
index 2c1df0943ce3..84f36b8fee0a 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,11 @@ Release date: 2014-01-05
 Core and Builtins
 -----------------
 
+- Issue #19576: PyGILState_Ensure() now initializes threads. At startup, Python
+  has no concrete GIL. If PyGILState_Ensure() is called from a new thread for
+  the first time and PyEval_InitThreads() was not called yet, a GIL needs to be
+  created.
+
 - Issue #17576: Deprecation warning emitted now when __int__() or __index__()
   return not int instance.
 
diff --git a/Python/pystate.c b/Python/pystate.c
index 6be71de2ae0b..a56e3089694e 100644
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -771,6 +771,11 @@ PyGILState_Ensure(void)
     assert(autoInterpreterState); /* Py_Initialize() hasn't been called! */
     tcur = (PyThreadState *)PyThread_get_key_value(autoTLSkey);
     if (tcur == NULL) {
+        /* At startup, Python has no concrete GIL. If PyGILState_Ensure() is
+           called from a new thread for the first time, we need the create the
+           GIL. */
+        PyEval_InitThreads();
+
         /* Create a new thread state for this thread */
         tcur = PyThreadState_New(autoInterpreterState);
         if (tcur == NULL)