diff --git a/neutron/db/db_base_plugin_v2.py b/neutron/db/db_base_plugin_v2.py
index 01f431fa753..fb8c859c9aa 100644
--- a/neutron/db/db_base_plugin_v2.py
+++ b/neutron/db/db_base_plugin_v2.py
@@ -1465,9 +1465,15 @@ class NeutronDbPluginV2(neutron_plugin_base_v2.NeutronPluginBaseV2,
         return result
 
     def _subnet_check_ip_allocations(self, context, subnet_id):
-        return context.session.query(
-            models_v2.IPAllocation).filter_by(
-                subnet_id=subnet_id).join(models_v2.Port).first()
+        return (context.session.query(models_v2.IPAllocation).
+                filter_by(subnet_id=subnet_id).join(models_v2.Port).first())
+
+    def _subnet_get_user_allocation(self, context, subnet_id):
+        """Check if there are any user ports on subnet and return first."""
+        return (context.session.query(models_v2.IPAllocation).
+                filter_by(subnet_id=subnet_id).join().
+                filter(~models_v2.Port.device_owner.
+                       in_(AUTO_DELETE_PORT_OWNERS)).first())
 
     def _subnet_check_ip_allocations_internal_router_ports(self, context,
                                                            subnet_id):
diff --git a/neutron/plugins/ml2/plugin.py b/neutron/plugins/ml2/plugin.py
index b9210377ffd..f3f8b2ab38c 100644
--- a/neutron/plugins/ml2/plugin.py
+++ b/neutron/plugins/ml2/plugin.py
@@ -828,6 +828,8 @@ class Ml2Plugin(db_base_plugin_v2.NeutronDbPluginV2,
         self.mechanism_manager.update_subnet_postcommit(mech_context)
         return updated_subnet
 
+    @oslo_db_api.wrap_db_retry(max_retries=db_api.MAX_RETRIES,
+                               retry_on_request=True)
     def delete_subnet(self, context, id):
         # REVISIT(rkukura) The super(Ml2Plugin, self).delete_subnet()
         # function is not used because it deallocates the subnet's addresses
@@ -875,13 +877,22 @@ class Ml2Plugin(db_base_plugin_v2.NeutronDbPluginV2,
                 if not is_auto_addr_subnet:
                     alloc = self._subnet_check_ip_allocations(context, id)
                     if alloc:
-                        LOG.info(_LI("Found port (%(port_id)s, %(ip)s) "
-                                     "having IP allocation on subnet "
-                                     "%(subnet)s, cannot delete"),
-                                 {'ip': alloc.ip_address,
-                                  'port_id': alloc.port_id,
-                                  'subnet': id})
-                        raise exc.SubnetInUse(subnet_id=id)
+                        user_alloc = self._subnet_get_user_allocation(
+                            context, id)
+                        if user_alloc:
+                            LOG.info(_LI("Found port (%(port_id)s, %(ip)s) "
+                                         "having IP allocation on subnet "
+                                         "%(subnet)s, cannot delete"),
+                                     {'ip': user_alloc.ip_address,
+                                      'port_id': user_alloc.ports.id,
+                                      'subnet': id})
+                            raise exc.SubnetInUse(subnet_id=id)
+                        else:
+                            # allocation found and it was DHCP port
+                            # that appeared after autodelete ports were
+                            # removed - need to restart whole operation
+                            raise os_db_exception.RetryRequest(
+                                exc.SubnetInUse(subnet_id=id))
 
                 # If allocated is None, then all the IPAllocation were
                 # correctly deleted during the previous pass.
diff --git a/neutron/tests/unit/plugins/ml2/test_plugin.py b/neutron/tests/unit/plugins/ml2/test_plugin.py
index e9cd744064d..1d0d1378f4a 100644
--- a/neutron/tests/unit/plugins/ml2/test_plugin.py
+++ b/neutron/tests/unit/plugins/ml2/test_plugin.py
@@ -32,6 +32,7 @@ from neutron import context
 from neutron.db import api as db_api
 from neutron.db import db_base_plugin_v2 as base_plugin
 from neutron.db import l3_db
+from neutron.db import models_v2
 from neutron.extensions import external_net as external_net
 from neutron.extensions import multiprovidernet as mpnet
 from neutron.extensions import portbindings
@@ -268,7 +269,45 @@ class TestMl2NetworksV2(test_plugin.TestNetworksV2,
 
 class TestMl2SubnetsV2(test_plugin.TestSubnetsV2,
                        Ml2PluginV2TestCase):
-    pass
+    def test_delete_subnet_race_with_dhcp_port_creation(self):
+        with self.network() as network:
+            with self.subnet(network=network) as subnet:
+                subnet_id = subnet['subnet']['id']
+                attempt = [0]
+
+                def check_and_create_ports(context, subnet_id):
+                    """A method to emulate race condition.
+
+                    Adds dhcp port in the middle of subnet delete
+                    """
+                    if attempt[0] > 0:
+                        return False
+                    attempt[0] += 1
+                    data = {'port': {'network_id': network['network']['id'],
+                                     'tenant_id':
+                                     network['network']['tenant_id'],
+                                     'name': 'port1',
+                                     'admin_state_up': 1,
+                                     'device_owner':
+                                     constants.DEVICE_OWNER_DHCP,
+                                     'fixed_ips': [{'subnet_id': subnet_id}]}}
+                    port_req = self.new_create_request('ports', data)
+                    port_res = port_req.get_response(self.api)
+                    self.assertEqual(201, port_res.status_int)
+                    return (context.session.query(models_v2.IPAllocation).
+                            filter_by(subnet_id=subnet_id).
+                            join(models_v2.Port).first())
+
+                plugin = manager.NeutronManager.get_plugin()
+                # we mock _subnet_check_ip_allocations with method
+                # that creates DHCP port 'in the middle' of subnet_delete
+                # causing retry this way subnet is deleted on the
+                # second attempt
+                with mock.patch.object(plugin, '_subnet_check_ip_allocations',
+                                       side_effect=check_and_create_ports):
+                    req = self.new_delete_request('subnets', subnet_id)
+                    res = req.get_response(self.api)
+                    self.assertEqual(204, res.status_int)
 
 
 class TestMl2PortsV2(test_plugin.TestPortsV2, Ml2PluginV2TestCase):