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BUG: KCSAN: data-race in __mark_inode_dirty / __writeback_single_inode

read-write to 0xffff888106530650 of 8 bytes by task 20176 on cpu 0:
 __writeback_single_inode+0x201/0x860 fs/fs-writeback.c:1661
 writeback_sb_inodes+0x514/0xad0 fs/fs-writeback.c:1916
 wb_writeback+0x252/0x6e0 fs/fs-writeback.c:2092
 wb_do_writeback fs/fs-writeback.c:2239 [inline]
 wb_workfn+0x1a8/0x8d0 fs/fs-writeback.c:2279
 process_one_work kernel/workqueue.c:2633 [inline]
 process_scheduled_works+0x5b8/0xa40 kernel/workqueue.c:2706
 worker_thread+0x525/0x730 kernel/workqueue.c:2787
 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 0xffff888106530650 of 8 bytes by task 20907 on cpu 1:
 __mark_inode_dirty+0x199/0x7d0 fs/fs-writeback.c:2474
 mark_buffer_dirty+0x165/0x250 fs/buffer.c:1204
 __block_commit_write fs/buffer.c:2175 [inline]
 block_write_end+0x158/0x2e0 fs/buffer.c:2251
 ext4_da_do_write_end fs/ext4/inode.c:2961 [inline]
 ext4_da_write_end+0x1ad/0x860 fs/ext4/inode.c:3034
 generic_perform_write+0x267/0x410 mm/filemap.c:3941
 ext4_buffered_write_iter+0x1f6/0x370 fs/ext4/file.c:299
 ext4_file_write_iter+0x297/0xe10
 call_write_iter include/linux/fs.h:2085 [inline]
 iter_file_splice_write+0x5de/0x950 fs/splice.c:743
 do_splice_from fs/splice.c:941 [inline]
 direct_splice_actor+0x167/0x2c0 fs/splice.c:1164
 splice_direct_to_actor+0x2fb/0x660 fs/splice.c:1108
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x3b9/0x960 fs/read_write.c:1295
 __do_sys_sendfile64 fs/read_write.c:1362 [inline]
 __se_sys_sendfile64 fs/read_write.c:1348 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0000000000020085 -> 0x0000000000000004

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 20907 Comm: syz-executor.4 Not tainted 6.8.0-rc2-syzkaller-00397-g56897d51886f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
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