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BUG: KCSAN: data-race in __xa_clear_mark / xas_find_marked

read-write to 0xffff88811a08c6c0 of 8 bytes by task 47 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 lib/xarray.c:922 [inline]
 __xa_clear_mark+0xf5/0x1e0 lib/xarray.c:2097
 __folio_end_writeback+0x177/0x470 mm/page-writeback.c:3024
 folio_end_writeback+0x71/0x3d0 mm/filemap.c:1660
 end_buffer_async_write+0x156/0x1f0 fs/buffer.c:419
 end_bio_bh_io_sync+0x79/0xa0 fs/buffer.c:2783
 bio_endio+0x377/0x410 block/bio.c:1645
 blk_update_request+0x336/0x730 block/blk-mq.c:987
 blk_mq_end_request block/blk-mq.c:1149 [inline]
 blk_mq_dispatch_rq_list+0x2f5/0xf80 block/blk-mq.c:2130
 __blk_mq_sched_dispatch_requests+0xb83/0xc60 block/blk-mq-sched.c:313
 blk_mq_sched_dispatch_requests+0x86/0x120 block/blk-mq-sched.c:329
 blk_mq_run_work_fn+0x66/0xe0 block/blk-mq.c:2532
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3321
 worker_thread+0x582/0x770 kernel/workqueue.c:3402
 kthread+0x486/0x510 kernel/kthread.c:464
 ret_from_fork+0xdd/0x150 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff88811a08c6c0 of 8 bytes by task 11517 on cpu 0:
 xas_find_chunk include/linux/xarray.h:1752 [inline]
 xas_find_marked+0x218/0x620 lib/xarray.c:1510
 find_get_entry+0x5d/0x380 mm/filemap.c:2038
 filemap_get_folios_tag+0x13b/0x210 mm/filemap.c:2306
 __filemap_fdatawait_range mm/filemap.c:530 [inline]
 filemap_fdatawait_keep_errors+0x6c/0x180 mm/filemap.c:633
 sync_bdevs+0x182/0x260 block/bdev.c:1298
 ksys_sync+0x8b/0xe0 fs/sync.c:106
 __ia32_sys_sync+0xe/0x20 fs/sync.c:113
 x64_sys_call+0x2e53/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:163
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xfffffffffffffc00 -> 0xffffffffffffe000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 11517 Comm: syz.7.3055 Not tainted 6.16.0-rc2-syzkaller-00047-g52da431bf03b #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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