diff -r e831a98b3f43 Python/thread_pthread.h
--- a/Python/thread_pthread.h	Sat Aug 16 01:03:39 2014 +0200
+++ b/Python/thread_pthread.h	Sat Aug 16 14:07:32 2014 +0200
@@ -608,7 +608,14 @@ PyThread_create_key(void)
 {
     pthread_key_t key;
     int fail = pthread_key_create(&key, NULL);
-    return fail ? -1 : key;
+    if (fail)
+        return -1;
+    if (key > INT_MAX) {
+        /* integer overflow */
+        pthread_key_delete(key);
+        return -1;
+    }
+    return (int)key;
 }
 
 void