syzbot

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BUG: KCSAN: data-race in kick_pool / wq_worker_running

read-write to 0xffff888237c2a524 of 4 bytes by task 3478 on cpu 0:
 wq_worker_running+0x95/0x120 kernel/workqueue.c:1400
 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+0x39c6/0x45e0 drivers/net/netdevsim/fib.c:1493
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3340
 worker_thread+0x582/0x770 kernel/workqueue.c:3421
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

read to 0xffff888237c2a524 of 4 bytes by task 4472 on cpu 1:
 need_more_worker kernel/workqueue.c:934 [inline]
 kick_pool+0x49/0x2d0 kernel/workqueue.c:1240
 __queue_work+0x897/0xae0 kernel/workqueue.c:2336
 queue_work_on+0xa9/0x130 kernel/workqueue.c:2386
 srcu_queue_delayed_work_on kernel/rcu/srcutree.c:899 [inline]
 srcu_schedule_cbs_sdp kernel/rcu/srcutree.c:912 [inline]
 srcu_gp_end kernel/rcu/srcutree.c:979 [inline]
 srcu_advance_state kernel/rcu/srcutree.c:1891 [inline]
 process_srcu+0x999/0xbc0 kernel/rcu/srcutree.c:1995
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3340
 worker_thread+0x582/0x770 kernel/workqueue.c:3421
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

value changed: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 4472 Comm: kworker/1:10 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: rcu_gp process_srcu
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