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BUG: KCSAN: data-race in kick_pool / wq_worker_running

read-write to 0xffff888237d299a4 of 4 bytes by task 3505 on cpu 1:
 wq_worker_running+0x98/0x130 kernel/workqueue.c:1400
 schedule_timeout+0xbc/0x170 kernel/time/sleep_timeout.c:99
 schedule_timeout_uninterruptible kernel/time/sleep_timeout.c:158 [inline]
 msleep+0x4f/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+0x13dd/0x2290 drivers/net/netdevsim/fib.c:1493
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x4de/0xa20 kernel/workqueue.c:3319
 worker_thread+0x52c/0x710 kernel/workqueue.c:3400
 kthread+0x4b7/0x540 kernel/kthread.c:464
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff888237d299a4 of 4 bytes by task 7300 on cpu 0:
 need_more_worker kernel/workqueue.c:934 [inline]
 kick_pool+0x4d/0x2c0 kernel/workqueue.c:1240
 __queue_work+0x8f8/0xbb0 kernel/workqueue.c:2342
 queue_work_on+0xdf/0x190 kernel/workqueue.c:2392
 nsim_fib_event_schedule_work drivers/net/netdevsim/fib.c:-1 [inline]
 nsim_fib_event_nb+0xbfb/0xd40 drivers/net/netdevsim/fib.c:1043
 notifier_call_chain kernel/notifier.c:85 [inline]
 atomic_notifier_call_chain+0x76/0x1d0 kernel/notifier.c:223
 call_fib_notifiers+0x66/0xa0 net/core/fib_notifier.c:35
 call_fib6_notifiers+0x32/0x40 net/ipv6/fib6_notifier.c:22
 call_fib6_entry_notifiers net/ipv6/ip6_fib.c:397 [inline]
 fib6_add_rt2node net/ipv6/ip6_fib.c:1231 [inline]
 fib6_add+0xec9/0x21c0 net/ipv6/ip6_fib.c:1488
 __ip6_ins_rt net/ipv6/route.c:1351 [inline]
 ip6_ins_rt+0x75/0xb0 net/ipv6/route.c:1361
 __ipv6_ifa_notify+0x358/0x850 net/ipv6/addrconf.c:6283
 ipv6_ifa_notify net/ipv6/addrconf.c:6322 [inline]
 addrconf_dad_completed+0xdf/0x8a0 net/ipv6/addrconf.c:4321
 addrconf_dad_work+0x8e6/0xc30 net/ipv6/addrconf.c:-1
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x4de/0xa20 kernel/workqueue.c:3319
 worker_thread+0x52c/0x710 kernel/workqueue.c:3400
 kthread+0x4b7/0x540 kernel/kthread.c:464
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:153
 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: 7300 Comm: kworker/u8:9 Not tainted 6.15.0-rc2-syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: ipv6_addrconf addrconf_dad_work
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