EXT4-fs (loop5): unmounting filesystem 00000000-0000-0000-0000-000000000000.
==================================================================
BUG: KCSAN: data-race in insert_work / wq_worker_running

read-write to 0xffff888237c2c8e4 of 4 bytes by task 8991 on cpu 0:
 wq_worker_running+0x98/0x120 kernel/workqueue.c:1068
 schedule_timeout+0xcc/0x230 kernel/time/timer.c:2167
 schedule_timeout_uninterruptible kernel/time/timer.c:2201 [inline]
 msleep+0x52/0x70 kernel/time/timer.c:2322
 nsim_fib4_rt_replace drivers/net/netdevsim/fib.c:402 [inline]
 nsim_fib4_rt_insert drivers/net/netdevsim/fib.c:434 [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+0x128a/0x2250 drivers/net/netdevsim/fib.c:1492
 process_one_work+0x434/0x860 kernel/workqueue.c:2597
 process_scheduled_works kernel/workqueue.c:2664 [inline]
 worker_thread+0x79a/0xa10 kernel/workqueue.c:2750
 kthread+0x1d7/0x210 kernel/kthread.c:389
 ret_from_fork+0x2e/0x40 arch/x86/kernel/process.c:145
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:296

read to 0xffff888237c2c8e4 of 4 bytes by task 3086 on cpu 1:
 __need_more_worker kernel/workqueue.c:827 [inline]
 insert_work+0x10e/0x190 kernel/workqueue.c:1560
 insert_wq_barrier kernel/workqueue.c:3029 [inline]
 start_flush_work kernel/workqueue.c:3347 [inline]
 __flush_work+0x339/0x3c0 kernel/workqueue.c:3385
 flush_work+0x17/0x20 kernel/workqueue.c:3407
 __lru_add_drain_all+0x3b9/0x420 mm/swap.c:897
 lru_add_drain_all+0x10/0x20 mm/swap.c:905
 invalidate_bdev+0x5a/0x80 block/bdev.c:86
 ext4_put_super+0x502/0x7f0 fs/ext4/super.c:1340
 generic_shutdown_super+0xd9/0x260 fs/super.c:499
 kill_block_super+0x3b/0x60 fs/super.c:1417
 deactivate_locked_super+0x6b/0xd0 fs/super.c:330
 deactivate_super+0x9b/0xb0 fs/super.c:361
 cleanup_mnt+0x272/0x2e0 fs/namespace.c:1254
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1261
 task_work_run+0x135/0x1a0 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xd1/0xe0 kernel/entry/common.c:171
 exit_to_user_mode_prepare+0x6c/0xb0 kernel/entry/common.c:204
 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
 syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:297
 do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 3086 Comm: syz-executor.5 Not tainted 6.5.0-rc3-syzkaller-00297-gd31e3792919e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023
==================================================================
EXT4-fs (loop5): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop5): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop5): unmounting filesystem 00000000-0000-0000-0000-000000000000.