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

write to 0xffff8880a059d188 of 8 bytes by task 3314 on cpu 1:
 iptunnel_xmit_stats include/net/ip_tunnels.h:459 [inline]
 ip6tunnel_xmit include/net/ip6_tunnel.h:165 [inline]
 udp_tunnel6_xmit_skb+0x474/0x4b0 net/ipv6/ip6_udp_tunnel.c:109
 send6+0x2d7/0x3a0 drivers/net/wireguard/socket.c:152
 wg_socket_send_skb_to_peer drivers/net/wireguard/socket.c:177 [inline]
 wg_socket_send_buffer_to_peer+0x186/0x210 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+0x3e1/0x9a0 kernel/workqueue.c:2269
 worker_thread+0x665/0xbe0 kernel/workqueue.c:2415
 kthread+0x20d/0x230 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

read to 0xffff8880a059d188 of 8 bytes by task 25569 on cpu 0:
 iptunnel_xmit_stats include/net/ip_tunnels.h:459 [inline]
 ip6tunnel_xmit include/net/ip6_tunnel.h:165 [inline]
 udp_tunnel6_xmit_skb+0x462/0x4b0 net/ipv6/ip6_udp_tunnel.c:109
 send6+0x2d7/0x3a0 drivers/net/wireguard/socket.c:152
 wg_socket_send_skb_to_peer drivers/net/wireguard/socket.c:177 [inline]
 wg_socket_send_buffer_to_peer+0x186/0x210 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+0x3e1/0x9a0 kernel/workqueue.c:2269
 worker_thread+0x665/0xbe0 kernel/workqueue.c:2415
 kthread+0x20d/0x230 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 25569 Comm: kworker/u4:5 Not tainted 5.8.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: wg-kex-wg0 wg_packet_handshake_send_worker
==================================================================