==================================================================
BUG: KCSAN: data-race in udp_tunnel6_xmit_skb / udp_tunnel6_xmit_skb

read to 0xffff888137c721b0 of 8 bytes by task 9540 on cpu 1:
 iptunnel_xmit_stats include/net/ip_tunnels.h:461 [inline]
 ip6tunnel_xmit include/net/ip6_tunnel.h:166 [inline]
 udp_tunnel6_xmit_skb+0x483/0x4d0 net/ipv6/ip6_udp_tunnel.c:109
 send6+0x2f7/0x3c0 drivers/net/wireguard/socket.c:152
 wg_socket_send_skb_to_peer+0xbb/0x130 drivers/net/wireguard/socket.c:177
 wg_socket_send_buffer_to_peer+0xf7/0x120 drivers/net/wireguard/socket.c:199
 wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:40 [inline]
 wg_packet_handshake_send_worker+0x109/0x150 drivers/net/wireguard/send.c:51
 process_one_work+0x3e3/0x970 kernel/workqueue.c:2289
 worker_thread+0x638/0xaa0 kernel/workqueue.c:2436
 kthread+0x1bf/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30

write to 0xffff888137c721b0 of 8 bytes by task 9539 on cpu 0:
 iptunnel_xmit_stats include/net/ip_tunnels.h:461 [inline]
 ip6tunnel_xmit include/net/ip6_tunnel.h:166 [inline]
 udp_tunnel6_xmit_skb+0x495/0x4d0 net/ipv6/ip6_udp_tunnel.c:109
 send6+0x2f7/0x3c0 drivers/net/wireguard/socket.c:152
 wg_socket_send_skb_to_peer+0xbb/0x130 drivers/net/wireguard/socket.c:177
 wg_socket_send_buffer_to_peer+0xf7/0x120 drivers/net/wireguard/socket.c:199
 wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:40 [inline]
 wg_packet_handshake_send_worker+0x109/0x150 drivers/net/wireguard/send.c:51
 process_one_work+0x3e3/0x970 kernel/workqueue.c:2289
 worker_thread+0x638/0xaa0 kernel/workqueue.c:2436
 kthread+0x1bf/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30

value changed: 0x00000000000001e9 -> 0x00000000000001ea

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 9539 Comm: kworker/u4:22 Not tainted 5.17.0-syzkaller-09727-g34af78c4e616-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: wg-kex-wg0 wg_packet_handshake_send_worker
==================================================================