@@ -45,3 +45,4 @@ obj-$(CONFIG_BPF_SYSCALL) += bpf_sk_storage.o
obj-$(CONFIG_OF) += of_net.o
obj-$(CONFIG_NET_TEST) += net_test.o
obj-$(CONFIG_NET_DEVMEM) += devmem.o
+obj-$(CONFIG_DEBUG_NET_SMALL_RTNL) += rtnl_net_debug.o
new file mode 100644
@@ -0,0 +1,131 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Copyright Amazon.com Inc. or its affiliates. */
+
+#include <linux/init.h>
+#include <linux/netdevice.h>
+#include <linux/notifier.h>
+#include <linux/rtnetlink.h>
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+
+static int rtnl_net_debug_event(struct notifier_block *nb,
+ unsigned long event, void *ptr)
+{
+ struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+ struct net *net = dev_net(dev);
+ enum netdev_cmd cmd = event;
+
+ /* Keep enum and don't add default to trigger -Werror=switch */
+ switch (cmd) {
+ case NETDEV_UP:
+ case NETDEV_DOWN:
+ case NETDEV_REBOOT:
+ case NETDEV_CHANGE:
+ case NETDEV_REGISTER:
+ case NETDEV_UNREGISTER:
+ case NETDEV_CHANGEMTU:
+ case NETDEV_CHANGEADDR:
+ case NETDEV_PRE_CHANGEADDR:
+ case NETDEV_GOING_DOWN:
+ case NETDEV_CHANGENAME:
+ case NETDEV_FEAT_CHANGE:
+ case NETDEV_BONDING_FAILOVER:
+ case NETDEV_PRE_UP:
+ case NETDEV_PRE_TYPE_CHANGE:
+ case NETDEV_POST_TYPE_CHANGE:
+ case NETDEV_POST_INIT:
+ case NETDEV_PRE_UNINIT:
+ case NETDEV_RELEASE:
+ case NETDEV_NOTIFY_PEERS:
+ case NETDEV_JOIN:
+ case NETDEV_CHANGEUPPER:
+ case NETDEV_RESEND_IGMP:
+ case NETDEV_PRECHANGEMTU:
+ case NETDEV_CHANGEINFODATA:
+ case NETDEV_BONDING_INFO:
+ case NETDEV_PRECHANGEUPPER:
+ case NETDEV_CHANGELOWERSTATE:
+ case NETDEV_UDP_TUNNEL_PUSH_INFO:
+ case NETDEV_UDP_TUNNEL_DROP_INFO:
+ case NETDEV_CHANGE_TX_QUEUE_LEN:
+ case NETDEV_CVLAN_FILTER_PUSH_INFO:
+ case NETDEV_CVLAN_FILTER_DROP_INFO:
+ case NETDEV_SVLAN_FILTER_PUSH_INFO:
+ case NETDEV_SVLAN_FILTER_DROP_INFO:
+ case NETDEV_OFFLOAD_XSTATS_ENABLE:
+ case NETDEV_OFFLOAD_XSTATS_DISABLE:
+ case NETDEV_OFFLOAD_XSTATS_REPORT_USED:
+ case NETDEV_OFFLOAD_XSTATS_REPORT_DELTA:
+ case NETDEV_XDP_FEAT_CHANGE:
+ ASSERT_RTNL();
+ break;
+
+ /* Once an event fully supports RTNL_NET, move it here
+ * and remove "if (0)" below.
+ *
+ * case NETDEV_XXX:
+ * ASSERT_RTNL_NET(net);
+ * break;
+ */
+ }
+
+ /* Just to avoid unused-variable error for dev and net. */
+ if (0)
+ ASSERT_RTNL_NET(net);
+
+ return NOTIFY_DONE;
+}
+
+static int rtnl_net_debug_net_id;
+
+static int __net_init rtnl_net_debug_net_init(struct net *net)
+{
+ struct notifier_block *nb;
+
+ nb = net_generic(net, rtnl_net_debug_net_id);
+ nb->notifier_call = rtnl_net_debug_event;
+
+ return register_netdevice_notifier_net(net, nb);
+}
+
+static void __net_exit rtnl_net_debug_net_exit(struct net *net)
+{
+ struct notifier_block *nb;
+
+ nb = net_generic(net, rtnl_net_debug_net_id);
+ unregister_netdevice_notifier_net(net, nb);
+}
+
+static struct pernet_operations __net_initdata rtnl_net_debug_net_ops = {
+ .init = rtnl_net_debug_net_init,
+ .exit = rtnl_net_debug_net_exit,
+ .id = &rtnl_net_debug_net_id,
+ .size = sizeof(struct notifier_block),
+};
+
+static struct notifier_block rtnl_net_debug_block = {
+ .notifier_call = rtnl_net_debug_event,
+};
+
+static int __init rtnl_net_debug_init(void)
+{
+ int ret;
+
+ ret = register_pernet_device(&rtnl_net_debug_net_ops);
+ if (ret)
+ return ret;
+
+ ret = register_netdevice_notifier(&rtnl_net_debug_block);
+ if (ret)
+ unregister_pernet_subsys(&rtnl_net_debug_net_ops);
+
+ return ret;
+}
+
+static void __exit rtnl_net_debug_exit(void)
+{
+ unregister_netdevice_notifier(&rtnl_net_debug_block);
+ unregister_pernet_device(&rtnl_net_debug_net_ops);
+}
+
+subsys_initcall(rtnl_net_debug_init);
The global and per-net netdev notifier depend on RTNL, and its dependency is not so clear due to nested calls. Let's add a placeholder to place ASSERT_RTNL_NET() for each event. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> --- net/core/Makefile | 1 + net/core/rtnl_net_debug.c | 131 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 132 insertions(+) create mode 100644 net/core/rtnl_net_debug.c