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BUG: KCSAN: data-race in xas_clear_mark / xas_find_marked

read-write to 0xffff888106768fd8 of 8 bytes by task 39 on cpu 1:
 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_clear_bit include/asm-generic/bitops/instrumented-non-atomic.h:114 [inline]
 node_clear_mark lib/xarray.c:102 [inline]
 xas_clear_mark+0x90/0x180 lib/xarray.c:914
 __folio_start_writeback+0x2e8/0x450 mm/page-writeback.c:3078
 ext4_bio_write_folio+0x592/0x9a0 fs/ext4/page-io.c:557
 mpage_submit_folio fs/ext4/inode.c:1869 [inline]
 mpage_map_and_submit_buffers fs/ext4/inode.c:2115 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2254 [inline]
 ext4_do_writepages+0x13a7/0x2110 fs/ext4/inode.c:2679
 ext4_writepages+0x159/0x2e0 fs/ext4/inode.c:2768
 do_writepages+0x1d8/0x480 mm/page-writeback.c:2612
 __writeback_single_inode+0x91/0x870 fs/fs-writeback.c:1650
 writeback_sb_inodes+0x4de/0xaa0 fs/fs-writeback.c:1941
 wb_writeback+0x252/0x6f0 fs/fs-writeback.c:2117
 wb_do_writeback fs/fs-writeback.c:2264 [inline]
 wb_workfn+0x1a8/0x940 fs/fs-writeback.c:2304
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0x465/0x990 kernel/workqueue.c:3335
 worker_thread+0x526/0x730 kernel/workqueue.c:3416
 kthread+0x1d1/0x210 kernel/kthread.c:388
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

read to 0xffff888106768fd8 of 8 bytes by task 10926 on cpu 0:
 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:1968
 filemap_get_folios_tag+0x136/0x210 mm/filemap.c:2218
 mpage_prepare_extent_to_map+0x329/0xb80 fs/ext4/inode.c:2392
 ext4_do_writepages+0x6ea/0x2110 fs/ext4/inode.c:2632
 ext4_writepages+0x159/0x2e0 fs/ext4/inode.c:2768
 do_writepages+0x1d8/0x480 mm/page-writeback.c:2612
 filemap_fdatawrite_wbc+0xdb/0x100 mm/filemap.c:397
 __filemap_fdatawrite_range mm/filemap.c:430 [inline]
 __filemap_fdatawrite mm/filemap.c:436 [inline]
 filemap_flush+0x61/0x90 mm/filemap.c:463
 ext4_alloc_da_blocks+0x50/0x130 fs/ext4/inode.c:3072
 ext4_release_file+0x5f/0x1c0 fs/ext4/file.c:169
 __fput+0x2c1/0x660 fs/file_table.c:422
 ____fput+0x15/0x20 fs/file_table.c:450
 task_work_run+0x13a/0x1a0 kernel/task_work.c:180
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0x5fd/0x1740 kernel/exit.c:878
 do_group_exit+0x102/0x150 kernel/exit.c:1027
 get_signal+0xf2f/0x1080 kernel/signal.c:2911
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 irqentry_exit_to_user_mode+0x94/0x130 kernel/entry/common.c:231
 irqentry_exit+0x12/0x50 kernel/entry/common.c:334
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

value changed: 0xfffffffffc000000 -> 0xffffffff00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 10926 Comm: syz-executor.0 Not tainted 6.9.0-rc5-syzkaller-00036-g9d1ddab261f3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
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syz-executor.0 (10926) used greatest stack depth: 9568 bytes left