syzbot

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BUG: KCSAN: data-race in __mark_inode_dirty / __writeback_single_inode

write to 0xffff88811f5c6b20 of 8 bytes by task 23363 on cpu 1:
 __writeback_single_inode+0x1f6/0x590 fs/fs-writeback.c:1634
 writeback_sb_inodes+0x4dd/0xa30 fs/fs-writeback.c:1889
 __writeback_inodes_wb+0xa0/0x1b0 fs/fs-writeback.c:1960
 wb_writeback+0x280/0x650 fs/fs-writeback.c:2065
 wb_check_background_flush fs/fs-writeback.c:2131 [inline]
 wb_do_writeback+0x5b3/0x600 fs/fs-writeback.c:2219
 wb_workfn+0x88/0x260 fs/fs-writeback.c:2246
 process_one_work+0x3d3/0x720 kernel/workqueue.c:2289
 worker_thread+0x618/0xa70 kernel/workqueue.c:2436
 kthread+0x1a9/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

read to 0xffff88811f5c6b20 of 8 bytes by task 2205 on cpu 0:
 __mark_inode_dirty+0x4f/0x730 fs/fs-writeback.c:2401
 mark_inode_dirty include/linux/fs.h:2465 [inline]
 generic_write_end+0x175/0x350 fs/buffer.c:2184
 ext4_da_write_end+0x26c/0x620 fs/ext4/inode.c:3175
 generic_perform_write+0x264/0x3f0 mm/filemap.c:3783
 ext4_buffered_write_iter+0x235/0x3e0 fs/ext4/file.c:285
 ext4_file_write_iter+0x2bb/0x11b0
 __kernel_write_iter+0x157/0x380 fs/read_write.c:517
 dump_emit_page+0x3de/0x830 fs/coredump.c:864
 dump_user_range+0x5e/0x200 fs/coredump.c:915
 elf_core_dump+0x1b4f/0x1c60 fs/binfmt_elf.c:2137
 do_coredump+0xed7/0x1790 fs/coredump.c:762
 get_signal+0xa04/0xc70 kernel/signal.c:2845
 arch_do_signal_or_restart+0x85/0x290 arch/x86/kernel/signal.c:306
 exit_to_user_mode_loop+0x78/0x130 kernel/entry/common.c:168
 exit_to_user_mode_prepare kernel/entry/common.c:203 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
 syscall_exit_to_user_mode+0x6a/0x90 kernel/entry/common.c:296
 do_syscall_64+0x37/0x70 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0000000000020087 -> 0x0000000000000004

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 2205 Comm: syz-executor.5 Not tainted 6.2.0-rc6-syzkaller-00003-g22b8077d0fce-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
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