batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems!
batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1
batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems!
batman_adv: batadv0: Interface activated: batadv_slave_1
==================================================================
BUG: KCSAN: data-race in dev_get_tstats64 / iptunnel_xmit

read-write to 0xffffe8ffffd71390 of 8 bytes by task 3062 on cpu 1:
 iptunnel_xmit_stats include/net/ip_tunnels.h:449 [inline]
 iptunnel_xmit+0x39e/0x460 net/ipv4/ip_tunnel_core.c:87
 udp_tunnel_xmit_skb+0x15d/0x170 net/ipv4/udp_tunnel_core.c:190
 send4+0x386/0x530 drivers/net/wireguard/socket.c:85
 wg_socket_send_skb_to_peer drivers/net/wireguard/socket.c:174 [inline]
 wg_socket_send_buffer_to_peer+0x13c/0x1e0 drivers/net/wireguard/socket.c:199
 wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:40 [inline]
 wg_packet_handshake_send_worker+0xf9/0x140 drivers/net/wireguard/send.c:51
 process_one_work+0x3e1/0x950 kernel/workqueue.c:2275
 worker_thread+0x64a/0xaa0 kernel/workqueue.c:2421
 kthread+0x1fd/0x220 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

read to 0xffffe8ffffd71390 of 8 bytes by task 14020 on cpu 0:
 dev_fetch_sw_netstats net/core/dev.c:10440 [inline]
 dev_get_tstats64+0xf5/0x1a0 net/core/dev.c:10463
 dev_get_stats+0x63/0x160 net/core/dev.c:10405
 rtnl_fill_stats+0x45/0x320 net/core/rtnetlink.c:1211
 rtnl_fill_ifinfo+0xe92/0x2430 net/core/rtnetlink.c:1783
 rtmsg_ifinfo_build_skb+0xa2/0x130 net/core/rtnetlink.c:3798
 rtmsg_ifinfo_event net/core/rtnetlink.c:3830 [inline]
 rtmsg_ifinfo+0x55/0xc0 net/core/rtnetlink.c:3839
 __dev_notify_flags+0x63/0x3a0 net/core/dev.c:8512
 dev_change_flags+0xa2/0xc0 net/core/dev.c:8554
 do_setlink+0x741/0x21d0 net/core/rtnetlink.c:2708
 __rtnl_newlink net/core/rtnetlink.c:3376 [inline]
 rtnl_newlink+0xe58/0x12f0 net/core/rtnetlink.c:3491
 rtnetlink_rcv_msg+0x723/0x7c0 net/core/rtnetlink.c:5553
 netlink_rcv_skb+0x13e/0x240 net/netlink/af_netlink.c:2494
 rtnetlink_rcv+0x18/0x20 net/core/rtnetlink.c:5571
 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
 netlink_unicast+0x5df/0x6b0 net/netlink/af_netlink.c:1330
 netlink_sendmsg+0x6f8/0x7c0 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg net/socket.c:672 [inline]
 __sys_sendto+0x2a8/0x370 net/socket.c:1975
 __do_sys_sendto net/socket.c:1987 [inline]
 __se_sys_sendto net/socket.c:1983 [inline]
 __x64_sys_sendto+0x74/0x90 net/socket.c:1983
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 14020 Comm: syz-executor.3 Not tainted 5.11.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================