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BUG: KCSAN: data-race in __xa_clear_mark / xas_find_marked

read-write to 0xffff88811a0d3470 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_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
 _raw_spin_unlock_irqrestore+0x3c/0x60 kernel/locking/spinlock.c:194
 unix_stream_data_wait net/unix/af_unix.c:2754 [inline]
 unix_stream_read_generic+0xd07/0x1580 net/unix/af_unix.c:3009
 unix_stream_recvmsg+0xc3/0xf0 net/unix/af_unix.c:3172
 sock_recvmsg_nosec net/socket.c:1065 [inline]
 sock_recvmsg+0x139/0x170 net/socket.c:1087
 ____sys_recvmsg+0xf5/0x280 net/socket.c:2834
 ___sys_recvmsg+0x11f/0x370 net/socket.c:2876
 __sys_recvmsg net/socket.c:2909 [inline]
 __do_sys_recvmsg net/socket.c:2915 [inline]
 __se_sys_recvmsg net/socket.c:2912 [inline]
 __x64_sys_recvmsg+0xd1/0x160 net/socket.c:2912
 x64_sys_call+0x2b42/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:48
 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

read to 0xffff88811a0d3470 of 8 bytes by task 5264 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: 0xffffff8000000000 -> 0xffe0000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 5264 Comm: syz.2.448 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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EXT4-fs (loop2): re-mounted 00000000-0000-0000-0000-000000000000.