diff --git a/Lib/_pyio.py b/Lib/_pyio.py
index a3b89e7236b..74047bf475b 100644
--- a/Lib/_pyio.py
+++ b/Lib/_pyio.py
@@ -558,7 +558,11 @@ def readall(self):
             if not data:
                 break
             res += data
-        return bytes(res)
+        if res:
+            return bytes(res)
+        else:
+            # b'' or None
+            return data
 
     def readinto(self, b):
         """Read up to len(b) bytes into bytearray b.
diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
index f03e433a608..c0dc6ec7a2f 100644
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -833,14 +833,17 @@ def test_read_non_blocking(self):
         # Inject some None's in there to simulate EWOULDBLOCK
         rawio = self.MockRawIO((b"abc", b"d", None, b"efg", None, None, None))
         bufio = self.tp(rawio)
-
         self.assertEqual(b"abcd", bufio.read(6))
         self.assertEqual(b"e", bufio.read(1))
         self.assertEqual(b"fg", bufio.read())
         self.assertEqual(b"", bufio.peek(1))
-        self.assertTrue(None is bufio.read())
+        self.assertIsNone(bufio.read())
         self.assertEqual(b"", bufio.read())
 
+        rawio = self.MockRawIO((b"a", None, None))
+        self.assertEqual(b"a", rawio.readall())
+        self.assertIsNone(rawio.readall())
+
     def test_read_past_eof(self):
         rawio = self.MockRawIO((b"abc", b"d", b"efg"))
         bufio = self.tp(rawio)
diff --git a/Misc/NEWS b/Misc/NEWS
index e0bb60a6b3c..60209bf7a95 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -161,11 +161,16 @@ Core and Builtins
 Library
 -------
 
-- Issue #11109 -  New service_action method for BaseServer, used by
-  ForkingMixin class for cleanup. Initial Patch by Justin Wark.
-  
-- Issue #12045: Avoid duplicate execution of command in ctypes.util._get_soname().
-  Patch by Sijin Joseph.
+- Issue #12175: RawIOBase.readall() now returns None if read() returns None.
+
+- Issue #12175: FileIO.readall() now raises a ValueError instead of an IOError
+  if the file is closed.
+
+- Issue #11109: New service_action method for BaseServer, used by ForkingMixin
+  class for cleanup. Initial Patch by Justin Wark.
+
+- Issue #12045: Avoid duplicate execution of command in
+  ctypes.util._get_soname().  Patch by Sijin Joseph.
 
 - Issue #10818: Remove the Tk GUI and the serve() function of the pydoc module,
   pydoc -g has been deprecated in Python 3.2 and it has a new enhanced web
@@ -1062,9 +1067,6 @@ Core and Builtins
 Library
 -------
 
-- Issue #12175: FileIO.readall() now raises a ValueError instead of an IOError
-  if the file is closed.
-
 - Issue #10916: mmap should not segfault when a file is mapped using 0 as length
   and a non-zero offset, and an attempt to read past the end of file is made
   (IndexError is raised instead).  Patch by Ross Lagerwall.
diff --git a/Modules/_io/iobase.c b/Modules/_io/iobase.c
index ec7a2429295..f06f562947e 100644
--- a/Modules/_io/iobase.c
+++ b/Modules/_io/iobase.c
@@ -815,6 +815,14 @@ rawiobase_readall(PyObject *self, PyObject *args)
             Py_DECREF(chunks);
             return NULL;
         }
+        if (data == Py_None) {
+            if (PyList_GET_SIZE(chunks) == 0) {
+                Py_DECREF(chunks);
+                return data;
+            }
+            Py_DECREF(data);
+            break;
+        }
         if (!PyBytes_Check(data)) {
             Py_DECREF(chunks);
             Py_DECREF(data);