diff --git a/oslo_serialization/jsonutils.py b/oslo_serialization/jsonutils.py
index 0e310b1..a2a700b 100644
--- a/oslo_serialization/jsonutils.py
+++ b/oslo_serialization/jsonutils.py
@@ -33,6 +33,7 @@ import codecs
 import datetime
 import functools
 import inspect
+import io
 import itertools
 import json
 import uuid
@@ -161,7 +162,7 @@ def to_primitive(value, convert_instances=False, convert_datetime=True,
         # Python 3 does not have iteritems
         elif hasattr(value, 'items'):
             return recursive(dict(value.items()), level=level + 1)
-        elif hasattr(value, '__iter__'):
+        elif hasattr(value, '__iter__') and not isinstance(value, io.IOBase):
             return list(map(recursive, value))
         elif convert_instances and hasattr(value, '__dict__'):
             # Likely an instance of something. Watch for cycles.
diff --git a/oslo_serialization/tests/test_jsonutils.py b/oslo_serialization/tests/test_jsonutils.py
index e04b9dc..f076822 100644
--- a/oslo_serialization/tests/test_jsonutils.py
+++ b/oslo_serialization/tests/test_jsonutils.py
@@ -401,6 +401,16 @@ class ToPrimitiveTestCase(test_base.BaseTestCase):
         ret = jsonutils.to_primitive(obj, fallback=lambda _: 'fallback')
         self.assertEqual('fallback', ret)
 
+    def test_fallback_typeerror_IO_object(self):
+        # IO Objects are not callable, cause a TypeError in to_primitive()
+        obj = io.IOBase
+
+        ret = jsonutils.to_primitive(obj)
+        self.assertEqual(str(obj), ret)
+
+        ret = jsonutils.to_primitive(obj, fallback=lambda _: 'fallback')
+        self.assertEqual('fallback', ret)
+
     def test_exception(self):
         self.assertIn(jsonutils.to_primitive(ValueError("an exception")),
                       ["ValueError('an exception',)",
diff --git a/releasenotes/notes/bug-1908607-fix-json-to_primitive-IO-OBjects-04faff4a1b5cf48f.yaml b/releasenotes/notes/bug-1908607-fix-json-to_primitive-IO-OBjects-04faff4a1b5cf48f.yaml
new file mode 100644
index 0000000..0246ef7
--- /dev/null
+++ b/releasenotes/notes/bug-1908607-fix-json-to_primitive-IO-OBjects-04faff4a1b5cf48f.yaml
@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    `Bug #1908607 <https://bugs.launchpad.net/cinder/+bug/1908607>`_: Fix
+    json to_primitive when using IO OBjects.