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BUG: KCSAN: data-race in xfrm_lookup_with_ifid / xfrm_lookup_with_ifid

write to 0xffff888157ec7508 of 8 bytes by task 5456 on cpu 1:
 xfrm_lookup_with_ifid+0x1039/0x1830 net/xfrm/xfrm_policy.c:3137
 xfrm_lookup net/xfrm/xfrm_policy.c:3189 [inline]
 xfrm_lookup_route+0x37/0x100 net/xfrm/xfrm_policy.c:3200
 ip6_dst_lookup_flow+0x94/0xc0 net/ipv6/ip6_output.c:1206
 send6+0x238/0x3b0 drivers/net/wireguard/socket.c:139
 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+0x3f6/0x960 kernel/workqueue.c:2307
 worker_thread+0x616/0xa70 kernel/workqueue.c:2454
 kthread+0x1bf/0x1e0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30

write to 0xffff888157ec7508 of 8 bytes by task 5386 on cpu 0:
 xfrm_lookup_with_ifid+0x1039/0x1830 net/xfrm/xfrm_policy.c:3137
 xfrm_lookup net/xfrm/xfrm_policy.c:3189 [inline]
 xfrm_lookup_route+0x37/0x100 net/xfrm/xfrm_policy.c:3200
 ip6_dst_lookup_flow+0x94/0xc0 net/ipv6/ip6_output.c:1206
 send6+0x238/0x3b0 drivers/net/wireguard/socket.c:139
 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+0x3f6/0x960 kernel/workqueue.c:2307
 worker_thread+0x616/0xa70 kernel/workqueue.c:2454
 kthread+0x1bf/0x1e0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30

value changed: 0x000000019e021263 -> 0x000000019e021266

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 5386 Comm: kworker/u4:18 Tainted: G        W         5.17.0-rc2-syzkaller-00064-gc36c04c2e132 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: wg-kex-wg2 wg_packet_handshake_send_worker
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