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BUG: KCSAN: data-race in wg_packet_send_staged_packets / wg_packet_send_staged_packets

write to 0xffff888013719a48 of 4 bytes by task 17 on cpu 1:
 wg_cpumask_next_online drivers/net/wireguard/queueing.h:134 [inline]
 wg_queue_enqueue_per_device_and_peer drivers/net/wireguard/queueing.h:153 [inline]
 wg_packet_create_data drivers/net/wireguard/send.c:326 [inline]
 wg_packet_send_staged_packets+0x5d5/0x990 drivers/net/wireguard/send.c:396
 wg_packet_send_keepalive+0xea/0x100 drivers/net/wireguard/send.c:239
 wg_receive_handshake_packet drivers/net/wireguard/receive.c:193 [inline]
 wg_packet_handshake_receive_worker+0x302/0x440 drivers/net/wireguard/receive.c:220
 process_one_work+0x3e1/0x950 kernel/workqueue.c:2272
 worker_thread+0x635/0xb90 kernel/workqueue.c:2418
 kthread+0x1fa/0x220 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

read to 0xffff888013719a48 of 4 bytes by task 5 on cpu 0:
 wg_cpumask_next_online drivers/net/wireguard/queueing.h:130 [inline]
 wg_queue_enqueue_per_device_and_peer drivers/net/wireguard/queueing.h:153 [inline]
 wg_packet_create_data drivers/net/wireguard/send.c:326 [inline]
 wg_packet_send_staged_packets+0x592/0x990 drivers/net/wireguard/send.c:396
 wg_packet_send_keepalive+0xea/0x100 drivers/net/wireguard/send.c:239
 wg_receive_handshake_packet drivers/net/wireguard/receive.c:193 [inline]
 wg_packet_handshake_receive_worker+0x302/0x440 drivers/net/wireguard/receive.c:220
 process_one_work+0x3e1/0x950 kernel/workqueue.c:2272
 worker_thread+0x635/0xb90 kernel/workqueue.c:2418
 kthread+0x1fa/0x220 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.10.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: wg-kex-wg1 wg_packet_handshake_receive_worker
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