diff --git a/nova/tests/virt/test_diagnostics.py b/nova/tests/virt/test_diagnostics.py
index 3f0b5b3ca4b6..f3969fc09f9f 100644
--- a/nova/tests/virt/test_diagnostics.py
+++ b/nova/tests/virt/test_diagnostics.py
@@ -12,6 +12,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from nova import exception
 from nova import test
 from nova.virt import diagnostics
 
@@ -208,3 +209,23 @@ class DiagnosticsTests(test.NoDBTestCase):
                     'version': '1.0'}
         result = diags.serialize()
         self.assertEqual(expected, result)
+
+    def test_diagnostics_invalid_input(self):
+        self.assertRaises(exception.InvalidInput,
+                          diagnostics.Diagnostics,
+                          cpu_details='invalid type')
+        self.assertRaises(exception.InvalidInput,
+                          diagnostics.Diagnostics,
+                          cpu_details=['invalid entry'])
+        self.assertRaises(exception.InvalidInput,
+                          diagnostics.Diagnostics,
+                          nic_details='invalid type')
+        self.assertRaises(exception.InvalidInput,
+                          diagnostics.Diagnostics,
+                          nic_details=['invalid entry'])
+        self.assertRaises(exception.InvalidInput,
+                          diagnostics.Diagnostics,
+                          disk_details='invalid type')
+        self.assertRaises(exception.InvalidInput,
+                          diagnostics.Diagnostics,
+                          disk_details=['invalid entry'])
diff --git a/nova/virt/diagnostics.py b/nova/virt/diagnostics.py
index f9fea5c5720c..2538ad1c091f 100644
--- a/nova/virt/diagnostics.py
+++ b/nova/virt/diagnostics.py
@@ -15,6 +15,9 @@
 
 import six
 
+from nova import exception
+from nova.i18n import _
+
 
 class CpuDiagnostics(object):
 
@@ -119,19 +122,31 @@ class Diagnostics(object):
         self.uptime = uptime
         self.config_drive = config_drive
         if cpu_details:
+            self._validate_type(cpu_details, CpuDiagnostics, 'cpu_details')
             self.cpu_details = cpu_details
         else:
             self.cpu_details = []
         if nic_details:
+            self._validate_type(nic_details, NicDiagnostics, 'nic_details')
             self.nic_details = nic_details
         else:
             self.nic_details = []
         if disk_details:
+            self._validate_type(disk_details, DiskDiagnostics, 'disk_details')
             self.disk_details = disk_details
         else:
             self.disk_details = []
         self.memory_details = MemoryDiagnostics()
 
+    def _validate_type(self, input, type, str_input):
+        if not isinstance(input, list):
+            reason = _("Invalid type for %s") % str_input
+            raise exception.InvalidInput(reason=reason)
+        for i in input:
+            if not isinstance(i, type):
+                reason = _("Invalid type for %s entry") % str_input
+                raise exception.InvalidInput(reason=reason)
+
     def add_cpu(self, time=0):
         self.cpu_details.append(CpuDiagnostics(time=time))