diff --git a/neutron/agent/linux/ovs_lib.py b/neutron/agent/linux/ovs_lib.py
index 5428404..417bf98 100644
--- a/neutron/agent/linux/ovs_lib.py
+++ b/neutron/agent/linux/ovs_lib.py
@@ -525,9 +525,14 @@ def check_ovs_vxlan_version(root_helper):
                                             min_required_version,
                                             'userspace', 'VXLAN')
     # Now check the kernel version
-    _compare_installed_and_required_version(installed_klm_version,
-                                            min_required_version,
-                                            'kernel', 'VXLAN')
+    if installed_klm_version:
+        _compare_installed_and_required_version(installed_klm_version,
+                                                min_required_version,
+                                                'kernel', 'VXLAN')
+    else:
+        LOG.warning(_('Unable to determine Open vSwitch version. Please '
+                      'ensure that its version is %s or newer to use VXLAN '
+                      'tunnels with OVS.'), min_required_version)
 
 
 def _build_flow_expr_str(flow_dict, cmd):