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BUG: KCSAN: data-race in __xa_clear_mark / xas_find_marked

read-write to 0xffff88810678f6b8 of 8 bytes by interrupt 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_clear_bit include/asm-generic/bitops/instrumented-non-atomic.h:114 [inline]
 node_clear_mark lib/xarray.c:102 [inline]
 xas_clear_mark lib/xarray.c:922 [inline]
 __xa_clear_mark+0x103/0x1f0 lib/xarray.c:2094
 __folio_end_writeback+0x18d/0x4a0 mm/page-writeback.c:3047
 folio_end_writeback+0xcd/0x3d0 mm/filemap.c:1648
 end_buffer_async_write+0x1ca/0x230 fs/buffer.c:409
 end_bio_bh_io_sync+0x76/0xa0 fs/buffer.c:2748
 bio_endio+0x369/0x410 block/bio.c:1551
 blk_update_request+0x368/0x870 block/blk-mq.c:983
 blk_mq_end_request+0x26/0x50 block/blk-mq.c:1145
 lo_complete_rq+0xce/0x180 drivers/block/loop.c:371
 blk_complete_reqs block/blk-mq.c:1220 [inline]
 blk_done_softirq+0x74/0xb0 block/blk-mq.c:1225
 handle_softirqs+0xbf/0x280 kernel/softirq.c:579
 run_ksoftirqd+0x1c/0x30 kernel/softirq.c:968
 smpboot_thread_fn+0x345/0x560 kernel/smpboot.c:164
 kthread+0x4b7/0x540 kernel/kthread.c:464
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff88810678f6b8 of 8 bytes by task 10163 on cpu 1:
 xas_find_chunk include/linux/xarray.h:1746 [inline]
 xas_find_marked+0x21d/0x660 lib/xarray.c:1510
 find_get_entry+0x5d/0x370 mm/filemap.c:2027
 filemap_get_folios_tag+0x13e/0x220 mm/filemap.c:2294
 __filemap_fdatawait_range mm/filemap.c:530 [inline]
 filemap_write_and_wait_range+0x1e3/0x370 mm/filemap.c:700
 filemap_write_and_wait include/linux/pagemap.h:68 [inline]
 sync_blockdev block/bdev.c:222 [inline]
 bdev_release+0xea/0x420 block/bdev.c:1088
 blkdev_release+0x15/0x20 block/fops.c:660
 __fput+0x2ac/0x640 fs/file_table.c:465
 ____fput+0x1c/0x30 fs/file_table.c:493
 task_work_run+0x13c/0x1b0 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xa8/0x120 kernel/entry/common.c:218
 do_syscall_64+0xd6/0x1c0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffffffffffffff00 -> 0xfffffffffffff000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 10163 Comm: syz.7.2649 Not tainted 6.15.0-rc2-syzkaller-00037-g834a4a689699 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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