--- /dev/null
+debug northbound notifications
+! debug northbound libyang
+debug northbound events
+debug northbound callbacks
+debug mgmt backend datastore frontend transaction
+debug mgmt client backend
+debug mgmt client frontend
+
+log timestamp precision 6
+log file frr.log debug
+
+interface r1-eth0
+ ip address 101.0.0.1/24
+ ipv6 address 2101::1/64
+exit
\ No newline at end of file
--- /dev/null
+# -*- coding: utf-8 eval: (blacken-mode 1) -*-
+# SPDX-License-Identifier: ISC
+#
+# July 13 2023, Christian Hopps <chopps@labn.net>
+#
+# Copyright (c) 2023, LabN Consulting, L.L.C.
+#
+"""
+Test mgmtd regressions
+
+"""
+import pytest
+from lib.topogen import Topogen
+
+pytestmark = [pytest.mark.staticd]
+
+
+@pytest.fixture(scope="module")
+def tgen(request):
+ "Setup/Teardown the environment and provide tgen argument to tests"
+
+ topodef = {"s1": ("r1",)}
+ tgen = Topogen(topodef, request.module.__name__)
+ tgen.start_topology()
+ tgen.gears["r1"].load_frr_config("frr.conf")
+ tgen.start_router()
+ yield tgen
+ tgen.stop_topology()
+
+
+def test_regression_issue_13920(tgen):
+ """Issue #13920
+
+ ubuntu2204# conf t
+ ubuntu2204(config)# ip route 3.2.4.0/24 6.5.5.11 loop3
+ ubuntu2204(config)# nexthop-group nh2
+ ubuntu2204(config-nh-group)# nexthop 6.5.5.12
+ ubuntu2204(config-nh-group)# exi
+ ubuntu2204(config)# ip route 3.22.4.0/24 6.5.5.12
+ crash
+ """
+
+ r1 = tgen.gears["r1"]
+ r1.vtysh_multicmd(
+ """
+ conf t
+ nexthop-group nh2
+ exit
+ ip route 3.22.4.0/24 6.5.5.12
+ """
+ )
+ output = r1.net.checkRouterCores()
+ assert not output.strip()