diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -779,8 +779,6 @@
         lock = threading.Lock()
         self.assertRaises(RuntimeError, lock.release)
 
-    @unittest.skipUnless(sys.platform == 'darwin' and test.support.python_is_optimized(),
-                         'test macosx problem')
     def test_recursion_limit(self):
         # Issue 9670
         # test that excessive recursion within a non-main thread causes
diff --git a/Python/thread_pthread.h b/Python/thread_pthread.h
--- a/Python/thread_pthread.h
+++ b/Python/thread_pthread.h
@@ -28,7 +28,7 @@
  */
 #if defined(__APPLE__) && defined(THREAD_STACK_SIZE) && THREAD_STACK_SIZE == 0
 #undef  THREAD_STACK_SIZE
-#define THREAD_STACK_SIZE       0x500000
+#define THREAD_STACK_SIZE       0x800000
 #endif
 #if defined(__FreeBSD__) && defined(THREAD_STACK_SIZE) && THREAD_STACK_SIZE == 0
 #undef  THREAD_STACK_SIZE