==================================================================
BUG: KCSAN: data-race in kick_pool / wq_worker_running

read-write to 0xffff888237c29d64 of 4 bytes by task 3744 on cpu 0:
 wq_worker_running+0x95/0x120 kernel/workqueue.c:1404
 schedule_timeout+0xb7/0x170 kernel/time/sleep_timeout.c:99
 schedule_timeout_uninterruptible kernel/time/sleep_timeout.c:158 [inline]
 msleep+0x50/0x90 kernel/time/sleep_timeout.c:318
 nsim_fib4_rt_add drivers/net/netdevsim/fib.c:369 [inline]
 nsim_fib4_rt_insert drivers/net/netdevsim/fib.c:432 [inline]
 nsim_fib4_event drivers/net/netdevsim/fib.c:464 [inline]
 nsim_fib_event drivers/net/netdevsim/fib.c:884 [inline]
 nsim_fib_event_work+0x14a2/0x21a0 drivers/net/netdevsim/fib.c:1493
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3319
 worker_thread+0x582/0x770 kernel/workqueue.c:3400
 kthread+0x486/0x510 kernel/kthread.c:463
 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 0xffff888237c29d64 of 4 bytes by task 6224 on cpu 1:
 need_more_worker kernel/workqueue.c:938 [inline]
 kick_pool+0x49/0x2d0 kernel/workqueue.c:1244
 __queue_work+0x8cb/0xb50 kernel/workqueue.c:2340
 queue_work_on+0xd1/0x160 kernel/workqueue.c:2390
 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:5222 [inline]
 netdev_start_xmit include/linux/netdevice.h:5231 [inline]
 xmit_one net/core/dev.c:3827 [inline]
 dev_hard_start_xmit+0x122/0x3e0 net/core/dev.c:3843
 __dev_queue_xmit+0x10f9/0x2000 net/core/dev.c:4713
 dev_queue_xmit include/linux/netdevice.h:3361 [inline]
 neigh_connected_output+0x253/0x2c0 net/core/neighbour.c:1624
 neigh_output include/net/neighbour.h:547 [inline]
 ip6_finish_output2+0xa66/0xd30 net/ipv6/ip6_output.c:141
 __ip6_finish_output net/ipv6/ip6_output.c:-1 [inline]
 ip6_finish_output+0x3a4/0x540 net/ipv6/ip6_output.c:226
 NF_HOOK_COND include/linux/netfilter.h:307 [inline]
 ip6_output+0xfd/0x240 net/ipv6/ip6_output.c:248
 dst_output include/net/dst.h:461 [inline]
 NF_HOOK include/linux/netfilter.h:318 [inline]
 ndisc_send_skb+0x4cf/0x710 net/ipv6/ndisc.c:512
 ndisc_send_rs+0x2e7/0x360 net/ipv6/ndisc.c:722
 addrconf_dad_completed+0x60d/0x890 net/ipv6/addrconf.c:4360
 addrconf_dad_work+0x8ac/0xbf0 net/ipv6/addrconf.c:-1
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3319
 worker_thread+0x582/0x770 kernel/workqueue.c:3400
 kthread+0x486/0x510 kernel/kthread.c:463
 ret_from_fork+0xda/0x150 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 6224 Comm: kworker/u8:13 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: ipv6_addrconf addrconf_dad_work
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bridge0: port 1(bridge_slave_0) entered blocking state
bridge0: port 1(bridge_slave_0) entered forwarding state