syzbot

==================================================================
BUG: KCSAN: data-race in __mark_inode_dirty / __writeback_single_inode

read-write to 0xffff888106489890 of 8 bytes by task 6569 on cpu 1:
 __writeback_single_inode+0x201/0x860 fs/fs-writeback.c:1644
 writeback_sb_inodes+0x514/0xad0 fs/fs-writeback.c:1899
 wb_writeback+0x252/0x6e0 fs/fs-writeback.c:2075
 wb_do_writeback fs/fs-writeback.c:2222 [inline]
 wb_workfn+0x1a8/0x8d0 fs/fs-writeback.c:2262
 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:304

read to 0xffff888106489890 of 8 bytes by task 32623 on cpu 0:
 __mark_inode_dirty+0x199/0x7d0 fs/fs-writeback.c:2457
 mark_buffer_dirty+0x165/0x240 fs/buffer.c:1216
 __block_commit_write fs/buffer.c:2192 [inline]
 block_write_end+0x158/0x2e0 fs/buffer.c:2268
 ext4_da_do_write_end fs/ext4/inode.c:2951 [inline]
 ext4_da_write_end+0x1fc/0x9c0 fs/ext4/inode.c:3023
 generic_perform_write+0x267/0x410 mm/filemap.c:3980
 ext4_buffered_write_iter+0x1f6/0x370 fs/ext4/file.c:299
 ext4_file_write_iter+0xd6/0x1200
 call_write_iter include/linux/fs.h:1956 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x4ab/0x7d0 fs/read_write.c:584
 ksys_write+0xeb/0x1a0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0000000000020085 -> 0x0000000000000004

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 32623 Comm: syz-executor.5 Not tainted 6.6.0-rc3-syzkaller-00252-ge81a2dabc3f3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
==================================================================