syzbot

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BUG: KCSAN: data-race in kick_pool / wq_worker_running

read-write to 0xffff888237c2a8e4 of 4 bytes by task 3591 on cpu 0:
 wq_worker_running+0x9b/0x120 kernel/workqueue.c:1434
 schedule_timeout+0xca/0x180 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_fib6_rt_add drivers/net/netdevsim/fib.c:693 [inline]
 nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:759 [inline]
 nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
 nsim_fib_event+0x4526/0x4dc0 drivers/net/netdevsim/fib.c:889
 nsim_fib_event_work+0x133/0x200 drivers/net/netdevsim/fib.c:1493
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0x4d4/0x9a0 kernel/workqueue.c:3405
 worker_thread+0x569/0x750 kernel/workqueue.c:3486
 kthread+0x221/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff888237c2a8e4 of 4 bytes by task 35 on cpu 1:
 need_more_worker kernel/workqueue.c:952 [inline]
 kick_pool+0x49/0x2d0 kernel/workqueue.c:1274
 __queue_work+0x8e9/0xb90 kernel/workqueue.c:2402
 queue_work_on+0xa9/0x140 kernel/workqueue.c:2452
 srcu_queue_delayed_work_on kernel/rcu/srcutree.c:873 [inline]
 srcu_schedule_cbs_sdp kernel/rcu/srcutree.c:886 [inline]
 srcu_gp_end kernel/rcu/srcutree.c:951 [inline]
 srcu_advance_state kernel/rcu/srcutree.c:1869 [inline]
 process_srcu+0xa39/0xd90 kernel/rcu/srcutree.c:1973
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0x4d4/0x9a0 kernel/workqueue.c:3405
 worker_thread+0x569/0x750 kernel/workqueue.c:3486
 kthread+0x221/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 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: 35 Comm: kworker/1:1 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: rcu_gp process_srcu
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