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BUG: KCSAN: data-race in __xa_clear_mark / xas_find_marked

read-write to 0xffff888106d7b6b8 of 8 bytes by interrupt 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:2100
 __folio_end_writeback+0x177/0x470 mm/page-writeback.c:3022
 folio_end_writeback+0x71/0x3d0 mm/filemap.c:1660
 ext4_finish_bio+0x459/0x8c0 fs/ext4/page-io.c:144
 ext4_end_bio+0x298/0x3b0 fs/ext4/page-io.c:-1
 bio_endio+0x37b/0x420 block/bio.c:1651
 blk_update_request+0x336/0x730 block/blk-mq.c:989
 scsi_end_request+0x53/0x4c0 drivers/scsi/scsi_lib.c:637
 scsi_io_completion+0x7f/0x200 drivers/scsi/scsi_lib.c:1078
 scsi_finish_command+0x1c7/0x1e0 drivers/scsi/scsi.c:198
 scsi_complete+0xc3/0x1e0 drivers/scsi/scsi_lib.c:1547
 blk_complete_reqs block/blk-mq.c:1226 [inline]
 blk_done_softirq+0x77/0xb0 block/blk-mq.c:1231
 handle_softirqs+0xb7/0x290 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0x3a/0xc0 kernel/softirq.c:680
 common_interrupt+0x83/0x90 arch/x86/kernel/irq.c:318
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
 __preempt_count_dec_and_test arch/x86/include/asm/preempt.h:95 [inline]
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
 _raw_spin_unlock_irq+0x2f/0x50 kernel/locking/spinlock.c:202
 spin_unlock_irq include/linux/spinlock.h:401 [inline]
 filemap_remove_folio+0x75/0x1d0 mm/filemap.c:254
 truncate_inode_folio+0x42/0x50 mm/truncate.c:176
 shmem_undo_range+0x244/0xa80 mm/shmem.c:1153
 shmem_truncate_range mm/shmem.c:1269 [inline]
 shmem_evict_inode+0x134/0x520 mm/shmem.c:1397
 evict+0x2e3/0x550 fs/inode.c:810
 iput_final fs/inode.c:1897 [inline]
 iput+0x447/0x5b0 fs/inode.c:1923
 dentry_unlink_inode+0x24f/0x260 fs/dcache.c:466
 __dentry_kill+0x18d/0x4b0 fs/dcache.c:669
 dput+0x5e/0xd0 fs/dcache.c:911
 __fput+0x444/0x650 fs/file_table.c:476
 ____fput+0x1c/0x30 fs/file_table.c:496
 task_work_run+0x12e/0x1a0 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x483/0x15c0 kernel/exit.c:961
 do_group_exit+0xff/0x140 kernel/exit.c:1102
 get_signal+0xe59/0xf70 kernel/signal.c:3034
 arch_do_signal_or_restart+0x96/0x480 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x7a/0x100 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x1d6/0x200 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888106d7b6b8 of 8 bytes by task 18184 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:2039
 filemap_get_folios_tag+0x13b/0x210 mm/filemap.c:2307
 __filemap_fdatawait_range mm/filemap.c:530 [inline]
 filemap_fdatawait_keep_errors+0x6c/0x180 mm/filemap.c:633
 wait_sb_inodes fs/fs-writeback.c:2715 [inline]
 sync_inodes_sb+0x39c/0x440 fs/fs-writeback.c:2837
 sync_inodes_one_sb+0x3d/0x50 fs/sync.c:77
 __iterate_supers+0x10d/0x220 fs/super.c:924
 iterate_supers+0x1f/0x30 fs/super.c:939
 ksys_sync+0x5c/0xe0 fs/sync.c:102
 __ia32_sys_sync+0xe/0x20 fs/sync.c:113
 x64_sys_call+0x2d10/0x2ff0 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: 0x000003c000000000 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 18184 Comm: syz.3.6145 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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