diff --git a/neutron/db/l3_db.py b/neutron/db/l3_db.py
index 1df69daa0be..76918f81e3e 100644
--- a/neutron/db/l3_db.py
+++ b/neutron/db/l3_db.py
@@ -1033,10 +1033,15 @@ class L3_NAT_dbonly_mixin(l3.RouterPluginBase,
                     subnets_id.extend([fixed_ip['subnet_id']
                                        for fixed_ip in port['fixed_ips']])
                 else:
-                    raise l3_exc.RouterInterfaceNotFound(
-                        router_id=router.id, port_id=rp.port_id)
+                    # due to race conditions maybe the port under analysis is
+                    # deleted, so instead returning a RouterInterfaceNotFound
+                    # we continue the analysis avoiding that port
+                    LOG.debug("Port %s could not be found, it might have been "
+                              "deleted concurrently. Will not be checked for "
+                              "an overlapping router interface.",
+                              rp.port_id)
 
-            if subnets_id:
+            if len(subnets_id) > 1:
                 id_filter = {'id': subnets_id}
                 subnets = self._core_plugin.get_subnets(context.elevated(),
                                                         filters=id_filter)
diff --git a/neutron/tests/base.py b/neutron/tests/base.py
index 7e5d9bb7c71..6640fe245b0 100644
--- a/neutron/tests/base.py
+++ b/neutron/tests/base.py
@@ -492,7 +492,11 @@ class BaseTestCase(DietTestCase):
                     root_helper_daemon=get_rootwrap_daemon_cmd())
 
     def _simulate_concurrent_requests_process_and_raise(self, calls, args):
+        self._simulate_concurrent_requests_process(calls, args,
+                                                   raise_on_exception=True)
 
+    def _simulate_concurrent_requests_process(self, calls, args,
+                                              raise_on_exception=False):
         class SimpleThread(threading.Thread):
             def __init__(self, q):
                 super(SimpleThread, self).__init__()
@@ -529,10 +533,16 @@ class BaseTestCase(DietTestCase):
             t.start()
         q.join()
 
+        threads_exceptions = []
         for t in threads:
             e = t.get_exception()
             if e:
-                raise e
+                if raise_on_exception:
+                    raise e
+                else:
+                    threads_exceptions.append(e)
+
+        return threads_exceptions
 
 
 class PluginFixture(fixtures.Fixture):
diff --git a/neutron/tests/fullstack/test_l3_agent.py b/neutron/tests/fullstack/test_l3_agent.py
index 84603266dc5..1a39efa844b 100644
--- a/neutron/tests/fullstack/test_l3_agent.py
+++ b/neutron/tests/fullstack/test_l3_agent.py
@@ -270,25 +270,37 @@ class TestL3Agent(base.BaseFullStackTestCase):
     def _test_concurrent_router_subnet_attachment_overlapping_cidr(self,
                                                                    ha=False):
         tenant_id = uuidutils.generate_uuid()
-        subnet_cidr = '10.100.0.0/24'
-        network1 = self.safe_client.create_network(
-            tenant_id, name='foo-network1')
-        subnet1 = self.safe_client.create_subnet(
-            tenant_id, network1['id'], subnet_cidr)
-        network2 = self.safe_client.create_network(
-            tenant_id, name='foo-network2')
-        subnet2 = self.safe_client.create_subnet(
-            tenant_id, network2['id'], subnet_cidr)
+        subnet_cidr = '10.200.0.0/24'
+        # to have many port interactions where race conditions would happen
+        # deleting ports meanwhile find operations to evaluate the overlapping
+        subnets = 10
+
+        funcs = []
+        args = []
         router = self.safe_client.create_router(tenant_id, ha=ha)
 
-        funcs = [self.safe_client.add_router_interface,
-                 self.safe_client.add_router_interface]
-        args = [(router['id'], subnet1['id']), (router['id'], subnet2['id'])]
-        self.assertRaises(
-            exceptions.BadRequest,
-            self._simulate_concurrent_requests_process_and_raise,
-            funcs,
-            args)
+        for i in range(subnets):
+            network_tmp = self.safe_client.create_network(
+                tenant_id, name='foo-network' + str(i))
+            subnet_tmp = self.safe_client.create_subnet(
+                tenant_id, network_tmp['id'], subnet_cidr)
+            funcs.append(self.safe_client.add_router_interface)
+            args.append((router['id'], subnet_tmp['id']))
+
+        exception_requests = self._simulate_concurrent_requests_process(
+            funcs, args)
+
+        if not all(type(e) == exceptions.BadRequest
+                   for e in exception_requests):
+            self.fail('Unexpected exception adding interfaces to router from '
+                      'different subnets overlapping')
+
+        if not len(exception_requests) >= (subnets - 1):
+            self.fail('If we have tried to associate %s subnets overlapping '
+                      'cidr to the router, we should have received at least '
+                      '%s or %s rejected requests, but we have only received '
+                      '%s', (str(subnets), str(subnets - 1), str(subnets),
+                             str(len(exception_requests))))
 
 
 class TestLegacyL3Agent(TestL3Agent):
@@ -441,7 +453,7 @@ class TestLegacyL3Agent(TestL3Agent):
     def test_router_fip_qos_after_admin_state_down_up(self):
         self._router_fip_qos_after_admin_state_down_up()
 
-    def test_concurrent_router_subnet_attachment_overlapping_cidr_(self):
+    def test_concurrent_router_subnet_attachment_overlapping_cidr(self):
         self._test_concurrent_router_subnet_attachment_overlapping_cidr()
 
 
@@ -601,6 +613,6 @@ class TestHAL3Agent(TestL3Agent):
     def test_router_fip_qos_after_admin_state_down_up(self):
         self._router_fip_qos_after_admin_state_down_up(ha=True)
 
-    def test_concurrent_router_subnet_attachment_overlapping_cidr_(self):
+    def test_concurrent_router_subnet_attachment_overlapping_cidr(self):
         self._test_concurrent_router_subnet_attachment_overlapping_cidr(
             ha=True)