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BUG: KCSAN: data-race in kick_pool / wq_worker_running

read-write to 0xffff888237d299e4 of 4 bytes by task 3380 on cpu 1:
 wq_worker_running+0x95/0x120 kernel/workqueue.c:1400
 io_schedule+0x3f/0x60 kernel/sched/core.c:7742
 bit_wait_io+0xc/0x60 kernel/sched/wait_bit.c:247
 __wait_on_bit+0x42/0xe0 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0x8d/0xb0 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:105 [inline]
 __wait_on_buffer+0x4d/0x60 fs/buffer.c:123
 wait_on_buffer include/linux/buffer_head.h:422 [inline]
 ext4_commit_super+0x1e4/0x280 fs/ext4/super.c:6226
 update_super_work+0x246/0x290 fs/ext4/super.c:794
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3319
 worker_thread+0x582/0x770 kernel/workqueue.c:3400
 kthread+0x486/0x510 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 0xffff888237d299e4 of 4 bytes by task 5694 on cpu 0:
 need_more_worker kernel/workqueue.c:934 [inline]
 kick_pool+0x49/0x2d0 kernel/workqueue.c:1240
 __queue_work+0x8d6/0xb60 kernel/workqueue.c:2342
 queue_work_on+0xd1/0x160 kernel/workqueue.c:2392
 __lru_add_drain_all+0x2c6/0x3f0 mm/swap.c:869
 lru_add_drain_all+0x10/0x20 mm/swap.c:883
 invalidate_bdev+0x47/0x70 block/bdev.c:101
 ext4_put_super+0x624/0x7d0 fs/ext4/super.c:1343
 generic_shutdown_super+0xe3/0x210 fs/super.c:642
 kill_block_super+0x2a/0x70 fs/super.c:1710
 ext4_kill_sb+0x42/0x80 fs/ext4/super.c:7393
 deactivate_locked_super+0x72/0x1c0 fs/super.c:473
 deactivate_super+0x97/0xa0 fs/super.c:506
 cleanup_mnt+0x269/0x2e0 fs/namespace.c:1435
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1442
 task_work_run+0x12e/0x1a0 kernel/task_work.c:227
 resume_user_mode_work+0x6a/0x70 include/linux/resume_user_mode.h:50
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x77/0xb0 kernel/entry/common.c:218
 do_syscall_64+0xdd/0x1a0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 5694 Comm: syz-executor Not tainted 6.15.0-rc3-syzkaller-00283-gf1a3944c860b #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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