diff --git a/cinder/tests/unit/test_volume_utils.py b/cinder/tests/unit/test_volume_utils.py
index ad7856429..c49b113a7 100644
--- a/cinder/tests/unit/test_volume_utils.py
+++ b/cinder/tests/unit/test_volume_utils.py
@@ -716,6 +716,11 @@ class VolumeUtilsTestCase(test.TestCase):
         self.assertEqual(pool,
                          volume_utils.extract_host(host, 'pool', True))
 
+    def test_extract_host_none_string(self):
+        self.assertRaises(exception.InvalidVolume,
+                          volume_utils.extract_host,
+                          None)
+
     def test_get_volume_rpc_host(self):
         host = 'Host@backend'
         # default level is 'backend'
diff --git a/cinder/volume/utils.py b/cinder/volume/utils.py
index 713351d29..0aec08aad 100644
--- a/cinder/volume/utils.py
+++ b/cinder/volume/utils.py
@@ -645,7 +645,8 @@ def extract_host(host, level='backend', default_pool_name=False):
                               string.  default_pool_name=True will return
                               DEFAULT_POOL_NAME, otherwise we return None.
                               Default value of this parameter is False.
-    :return: expected level of information
+    :return: expected information, string or None
+    :raises: exception.InvalidVolume
 
     For example:
         host = 'HostA@BackendB#PoolC'
@@ -662,6 +663,11 @@ def extract_host(host, level='backend', default_pool_name=False):
         ret = extract_host(host, 'pool', True)
         # ret is '_pool0'
     """
+
+    if host is None:
+        msg = _LE("volume is not assigned to a host")
+        raise exception.InvalidVolume(reason=msg)
+
     if level == 'host':
         # make sure pool is not included
         hst = host.split('#')[0]