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BUG: KCSAN: data-race in kick_pool / wq_worker_running

read-write to 0xffff888237c2b664 of 4 bytes by task 3401 on cpu 0:
 wq_worker_running+0x95/0x120 kernel/workqueue.c:1400
 schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:6935
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x414/0xa50 kernel/locking/mutex.c:747
 __mutex_lock_slowpath+0xa/0x10 kernel/locking/mutex.c:1035
 mutex_lock+0x27/0x30 kernel/locking/mutex.c:278
 pcpu_balance_workfn+0x4a/0xc00 mm/percpu.c:2200
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3321
 worker_thread+0x582/0x770 kernel/workqueue.c:3402
 kthread+0x486/0x510 kernel/kthread.c:464
 ret_from_fork+0xda/0x150 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff888237c2b664 of 4 bytes by task 14797 on cpu 1:
 need_more_worker kernel/workqueue.c:934 [inline]
 kick_pool+0x49/0x2d0 kernel/workqueue.c:1240
 __queue_work+0x8d6/0xb60 kernel/workqueue.c:2342
 queue_work_on+0xd1/0x160 kernel/workqueue.c:2392
 wg_queue_enqueue_per_device_and_peer drivers/net/wireguard/queueing.h:176 [inline]
 wg_packet_create_data drivers/net/wireguard/send.c:320 [inline]
 wg_packet_send_staged_packets+0x83d/0xab0 drivers/net/wireguard/send.c:388
 wg_xmit+0x5c7/0x6b0 drivers/net/wireguard/device.c:218
 __netdev_start_xmit include/linux/netdevice.h:5215 [inline]
 netdev_start_xmit include/linux/netdevice.h:5224 [inline]
 xmit_one net/core/dev.c:3830 [inline]
 dev_hard_start_xmit+0x122/0x3e0 net/core/dev.c:3846
 __dev_queue_xmit+0x10b9/0x1fb0 net/core/dev.c:4713
 dev_queue_xmit include/linux/netdevice.h:3355 [inline]
 neigh_connected_output+0x253/0x2c0 net/core/neighbour.c:1541
 neigh_output include/net/neighbour.h:539 [inline]
 ip_finish_output2+0x7bf/0x8b0 net/ipv4/ip_output.c:235
 __ip_finish_output net/ipv4/ip_output.c:-1 [inline]
 ip_finish_output+0x112/0x290 net/ipv4/ip_output.c:323
 NF_HOOK_COND include/linux/netfilter.h:306 [inline]
 ip_output+0xad/0x170 net/ipv4/ip_output.c:433
 dst_output include/net/dst.h:459 [inline]
 ip_local_out net/ipv4/ip_output.c:129 [inline]
 ip_send_skb+0x11d/0x140 net/ipv4/ip_output.c:1502
 udp_send_skb+0x6e3/0xa40 net/ipv4/udp.c:1197
 udp_sendmsg+0x1050/0x13b0 net/ipv4/udp.c:1485
 inet_sendmsg+0xac/0xd0 net/ipv4/af_inet.c:851
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x102/0x180 net/socket.c:727
 ____sys_sendmsg+0x345/0x4e0 net/socket.c:2566
 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2620
 __sys_sendmmsg+0x178/0x300 net/socket.c:2709
 __do_sys_sendmmsg net/socket.c:2736 [inline]
 __se_sys_sendmmsg net/socket.c:2733 [inline]
 __x64_sys_sendmmsg+0x57/0x70 net/socket.c:2733
 x64_sys_call+0x2f2f/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:308
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 14797 Comm: syz.6.4260 Not tainted 6.16.0-rc1-syzkaller-00003-gf09079bd04a9 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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