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BUG: KCSAN: data-race in __xa_set_mark / xas_find_marked

read-write to 0xffff88813f455b40 of 8 bytes by task 9164 on cpu 0:
 instrument_read_write include/linux/instrumented.h:55 [inline]
 __instrument_read_write_bitop include/asm-generic/bitops/instrumented-non-atomic.h:84 [inline]
 ___test_and_set_bit include/asm-generic/bitops/instrumented-non-atomic.h:99 [inline]
 node_set_mark lib/xarray.c:95 [inline]
 xas_set_mark lib/xarray.c:885 [inline]
 __xa_set_mark+0xdb/0x1b0 lib/xarray.c:1910
 __folio_mark_dirty+0x3c2/0x4e0 mm/page-writeback.c:2670
 mark_buffer_dirty+0x148/0x250 fs/buffer.c:1200
 __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:2955 [inline]
 ext4_da_write_end+0x1ad/0x860 fs/ext4/inode.c:3028
 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
 __kernel_write_iter+0x25f/0x480 fs/read_write.c:523
 dump_emit_page fs/coredump.c:890 [inline]
 dump_user_range+0x3a6/0x550 fs/coredump.c:951
 elf_core_dump+0x1a8e/0x1bb0 fs/binfmt_elf.c:2077
 do_coredump+0x102a/0x1890 fs/coredump.c:764
 get_signal+0xdb5/0x10a0 kernel/signal.c:2879
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:105 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:201 [inline]
 syscall_exit_to_user_mode+0x58/0x120 kernel/entry/common.c:212
 do_syscall_64+0xda/0x1d0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff88813f455b40 of 8 bytes by task 2805 on cpu 1:
 xas_find_chunk include/linux/xarray.h:1723 [inline]
 xas_find_marked+0x216/0x660 lib/xarray.c:1354
 find_get_entry+0x5d/0x290 mm/filemap.c:1961
 filemap_get_folios_tag+0x136/0x210 mm/filemap.c:2211
 mpage_prepare_extent_to_map+0x321/0xb70 fs/ext4/inode.c:2392
 ext4_do_writepages+0xa20/0x2100 fs/ext4/inode.c:2677
 ext4_writepages+0x15e/0x2e0 fs/ext4/inode.c:2768
 do_writepages+0x1c2/0x340 mm/page-writeback.c:2553
 __writeback_single_inode+0x91/0x860 fs/fs-writeback.c:1625
 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: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:243

value changed: 0x00000f8000000000 -> 0x00003f8000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 2805 Comm: kworker/u4:4 Not tainted 6.8.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
Workqueue: writeback wb_workfn (flush-8:0)
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