diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
index 3ee3378f8b26..d4ca82fec0b4 100644
--- a/tools/testing/selftests/net/Makefile
+++ b/tools/testing/selftests/net/Makefile
@@ -67,6 +67,7 @@ TEST_PROGS := \
 	nat6to4.sh \
 	ndisc_unsolicited_na_test.sh \
 	netdev-l2addr.sh \
+	netdev_lock.py \
 	netdevice.sh \
 	netns-name.sh \
 	netns-sysctl.sh \
diff --git a/tools/testing/selftests/net/netdev_lock.py b/tools/testing/selftests/net/netdev_lock.py
new file mode 100755
index 000000000000..0015b987eb9d
--- /dev/null
+++ b/tools/testing/selftests/net/netdev_lock.py
@@ -0,0 +1,42 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+
+"""Tests for the netdev instance lock."""
+
+from lib.py import ksft_run, ksft_exit
+from lib.py import ip
+from lib.py import NetNS
+
+
+def test_unreg_order() -> None:
+    """Dismantle two netns holding the same two kinds of ops locked device,
+    registered in opposite order.
+
+    unregister_netdevice_many_notify() takes the instance lock of every
+    device in the batch and holds them all at once, so the two kinds end up
+    nested one way round for the first netns and the other way round for
+    the second.
+    """
+    with NetNS() as ns1, NetNS() as ns2:
+        net1, net2 = str(ns1), str(ns2)
+
+        ip("link add du0 type dummy", ns=net1)
+        ip("link add nk0 type netkit peer name nk1", ns=net1)
+
+        ip("link add nk0 type netkit peer name nk1", ns=net2)
+        ip("link add du0 type dummy", ns=net2)
+
+        # only devices which are up get locked during unregister
+        for net in (net1, net2):
+            for dev in ("du0", "nk0", "nk1"):
+                ip(f"link set {dev} up", ns=net)
+
+
+def main() -> None:
+    """Ksft boilerplate main."""
+    ksft_run([test_unreg_order])
+    ksft_exit()
+
+
+if __name__ == "__main__":
+    main()