syzbot

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BUG: KCSAN: data-race in __writeback_single_inode / iput

read-write to 0xffff8881005b0438 of 8 bytes by task 22711 on cpu 1:
 __writeback_single_inode+0x201/0x860 fs/fs-writeback.c:1661
 writeback_sb_inodes+0x514/0xad0 fs/fs-writeback.c:1916
 __writeback_inodes_wb+0x9a/0x1a0 fs/fs-writeback.c:1987
 wb_writeback+0x264/0x6e0 fs/fs-writeback.c:2094
 wb_check_background_flush fs/fs-writeback.c:2164 [inline]
 wb_do_writeback fs/fs-writeback.c:2252 [inline]
 wb_workfn+0x67f/0x8d0 fs/fs-writeback.c:2279
 process_one_work kernel/workqueue.c:2630 [inline]
 process_scheduled_works+0x5b8/0xa30 kernel/workqueue.c:2703
 worker_thread+0x525/0x730 kernel/workqueue.c:2784
 kthread+0x1d7/0x210 kernel/kthread.c:388
 ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

read to 0xffff8881005b0438 of 8 bytes by task 23282 on cpu 0:
 iput+0x32/0x5b0 fs/inode.c:1791
 blkdev_get_no_open+0xaf/0xe0 block/bdev.c:722
 blkdev_get_by_dev+0x64/0x390 block/bdev.c:767
 bdev_open_by_dev+0x56/0xd0 block/bdev.c:840
 blkdev_open+0xfb/0x200 block/fops.c:600
 do_dentry_open+0x635/0xbd0 fs/open.c:948
 vfs_open+0x4a/0x50 fs/open.c:1082
 do_open fs/namei.c:3622 [inline]
 path_openat+0x1819/0x1d70 fs/namei.c:3779
 do_filp_open+0xf6/0x200 fs/namei.c:3809
 do_sys_openat2+0xab/0x110 fs/open.c:1440
 do_sys_open fs/open.c:1455 [inline]
 __do_sys_openat fs/open.c:1471 [inline]
 __se_sys_openat fs/open.c:1466 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1466
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0000000000020084 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 23282 Comm: udevd Tainted: G        W          6.6.0-syzkaller-10396-g4652b8e4f3ff #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
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