diff -r cc15d736d860 Python/pylifecycle.c
--- a/Python/pylifecycle.c	Mon Aug 24 20:31:53 2015 -0700
+++ b/Python/pylifecycle.c	Fri Sep 04 13:07:42 2015 +0200
@@ -1,4 +1,3 @@
-
 /* Python interpreter top-level routines, including init/exit */
 
 #include "Python.h"
@@ -1076,6 +1075,32 @@
     return dummy_fd >= 0;
 }
 
+
+static PyObject*
+create_stdio_checked(PyObject* io,
+                     int fd, int write_mode, char* name,
+                     char* encoding, char* errors)
+{
+    PyObject * std;
+
+    if (!is_valid_fd(fd)) {
+        std = Py_None;
+        Py_INCREF(std);
+        return std;
+    }
+    std = create_stdio(io, fd, write_mode, name, encoding, errors);
+    if (std == NULL) {
+        /* Protect from a race condition when fd becomes invalid aftter
+           the first check and before the create_stdio call
+        */
+        if (!is_valid_fd(fd)) {
+            std = Py_None;
+            Py_INCREF(std);
+        }
+    }
+    return std;
+}
+
 /* Initialize sys.stdin, stdout, stderr and builtins.open */
 static int
 initstdio(void)
@@ -1158,30 +1183,18 @@
      * and fileno() may point to an invalid file descriptor. For example
      * GUI apps don't have valid standard streams by default.
      */
-    if (!is_valid_fd(fd)) {
-        std = Py_None;
-        Py_INCREF(std);
-    }
-    else {
-        std = create_stdio(iomod, fd, 0, "<stdin>", encoding, errors);
-        if (std == NULL)
-            goto error;
-    } /* if (fd < 0) */
+    std = create_stdio_checked(iomod, fd, 0, "<stdin>", encoding, errors);
+    if (std == NULL)
+        goto error;
     PySys_SetObject("__stdin__", std);
     _PySys_SetObjectId(&PyId_stdin, std);
     Py_DECREF(std);
 
     /* Set sys.stdout */
     fd = fileno(stdout);
-    if (!is_valid_fd(fd)) {
-        std = Py_None;
-        Py_INCREF(std);
-    }
-    else {
-        std = create_stdio(iomod, fd, 1, "<stdout>", encoding, errors);
-        if (std == NULL)
-            goto error;
-    } /* if (fd < 0) */
+    std = create_stdio_checked(iomod, fd, 1, "<stdout>", encoding, errors);
+    if (std == NULL)
+        goto error;
     PySys_SetObject("__stdout__", std);
     _PySys_SetObjectId(&PyId_stdout, std);
     Py_DECREF(std);
@@ -1189,15 +1202,9 @@
 #if 1 /* Disable this if you have trouble debugging bootstrap stuff */
     /* Set sys.stderr, replaces the preliminary stderr */
     fd = fileno(stderr);
-    if (!is_valid_fd(fd)) {
-        std = Py_None;
-        Py_INCREF(std);
-    }
-    else {
-        std = create_stdio(iomod, fd, 1, "<stderr>", encoding, "backslashreplace");
-        if (std == NULL)
-            goto error;
-    } /* if (fd < 0) */
+    std = create_stdio_checked(iomod, fd, 1, "<stderr>", encoding, "backslashreplace");
+    if (std == NULL)
+        goto error;
 
     /* Same as hack above, pre-import stderr's codec to avoid recursion
        when import.c tries to write to stderr in verbose mode. */