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

read-write to 0xffff888237d29d64 of 4 bytes by task 23 on cpu 1:
 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+0x4cb/0x9d0 kernel/workqueue.c:3319
 worker_thread+0x582/0x770 kernel/workqueue.c:3400
 kthread+0x489/0x510 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 0xffff888237d29d64 of 4 bytes by task 9056 on cpu 0:
 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
 queue_work include/linux/workqueue.h:669 [inline]
 schedule_work include/linux/workqueue.h:730 [inline]
 nsim_fib_event_schedule_work drivers/net/netdevsim/fib.c:-1 [inline]
 nsim_fib_event_nb+0xb5a/0xcb0 drivers/net/netdevsim/fib.c:1043
 notifier_call_chain kernel/notifier.c:85 [inline]
 atomic_notifier_call_chain+0x73/0x1c0 kernel/notifier.c:223
 call_fib_notifiers+0x65/0xa0 net/core/fib_notifier.c:35
 call_fib6_notifiers+0x30/0x40 net/ipv6/fib6_notifier.c:22
 call_fib6_entry_notifiers net/ipv6/ip6_fib.c:409 [inline]
 fib6_add_rt2node+0xa39/0x1760 net/ipv6/ip6_fib.c:1244
 fib6_add+0x5b9/0xe00 net/ipv6/ip6_fib.c:1528
 __ip6_ins_rt net/ipv6/route.c:1351 [inline]
 ip6_ins_rt+0x73/0xb0 net/ipv6/route.c:1361
 __ipv6_ifa_notify+0x332/0x880 net/ipv6/addrconf.c:6283
 ipv6_ifa_notify net/ipv6/addrconf.c:6322 [inline]
 addrconf_dad_completed+0xdb/0x890 net/ipv6/addrconf.c:4320
 addrconf_dad_work+0x8ac/0xbf0 net/ipv6/addrconf.c:-1
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3319
 worker_thread+0x582/0x770 kernel/workqueue.c:3400
 kthread+0x489/0x510 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: 0 UID: 0 PID: 9056 Comm: kworker/u8:14 Not tainted 6.17.0-rc1-syzkaller-00199-gdfd4b508c8c6 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: ipv6_addrconf addrconf_dad_work
==================================================================
netdevsim netdevsim9 eth2: set [0, 0] type 1 family 0 port 8472 - 0
netdevsim netdevsim9 eth2: set [1, 0] type 2 family 0 port 6081 - 0
netdevsim netdevsim9 eth3: set [0, 0] type 1 family 0 port 8472 - 0
netdevsim netdevsim9 eth3: set [1, 0] type 2 family 0 port 6081 - 0