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BUG: KCSAN: data-race in xfrm_lookup_with_ifid / xfrm_lookup_with_ifid

write to 0xffff888178040d08 of 8 bytes by task 17440 on cpu 0:
 xfrm_lookup_with_ifid+0xce7/0x12d0 net/xfrm/xfrm_policy.c:3216
 xfrm_lookup net/xfrm/xfrm_policy.c:3268 [inline]
 xfrm_lookup_route+0x3b/0x100 net/xfrm/xfrm_policy.c:3279
 ip6_dst_lookup_flow+0x98/0xc0 net/ipv6/ip6_output.c:1246
 send6+0x23c/0x3a0 drivers/net/wireguard/socket.c:139
 wg_socket_send_skb_to_peer+0xbd/0x130 drivers/net/wireguard/socket.c:178
 wg_socket_send_buffer_to_peer+0xd6/0x100 drivers/net/wireguard/socket.c:200
 wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:40 [inline]
 wg_packet_handshake_send_worker+0x10c/0x150 drivers/net/wireguard/send.c:51
 process_one_work+0x3e6/0x750 kernel/workqueue.c:2405
 worker_thread+0x5f2/0xa10 kernel/workqueue.c:2552
 kthread+0x1d7/0x210 kernel/kthread.c:379
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

write to 0xffff888178040d08 of 8 bytes by task 17429 on cpu 1:
 xfrm_lookup_with_ifid+0xce7/0x12d0 net/xfrm/xfrm_policy.c:3216
 xfrm_lookup net/xfrm/xfrm_policy.c:3268 [inline]
 xfrm_lookup_route+0x3b/0x100 net/xfrm/xfrm_policy.c:3279
 ip6_dst_lookup_flow+0x98/0xc0 net/ipv6/ip6_output.c:1246
 send6+0x23c/0x3a0 drivers/net/wireguard/socket.c:139
 wg_socket_send_skb_to_peer+0xbd/0x130 drivers/net/wireguard/socket.c:178
 wg_socket_send_buffer_to_peer+0xd6/0x100 drivers/net/wireguard/socket.c:200
 wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:40 [inline]
 wg_packet_handshake_send_worker+0x10c/0x150 drivers/net/wireguard/send.c:51
 process_one_work+0x3e6/0x750 kernel/workqueue.c:2405
 worker_thread+0x5f2/0xa10 kernel/workqueue.c:2552
 kthread+0x1d7/0x210 kernel/kthread.c:379
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

value changed: 0x00000000645555c4 -> 0x00000000645555c6

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 17429 Comm: kworker/u4:8 Not tainted 6.3.0-syzkaller-13164-g78b421b6a7c6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
Workqueue: wg-kex-wg1 wg_packet_handshake_send_worker
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