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BUG: KCSAN: data-race in __xa_clear_mark / xas_find_marked

read-write to 0xffff88810064ad98 of 8 bytes by interrupt on cpu 1:
 instrument_read_write include/linux/instrumented.h:56 [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:2103
 __folio_end_writeback+0xe7/0x530 mm/page-writeback.c:2965
 folio_end_writeback_no_dropbehind+0x6d/0x200 mm/filemap.c:1672
 folio_end_writeback+0x1c/0x70 mm/filemap.c:1698
 ext4_finish_bio+0x454/0x770 fs/ext4/page-io.c:137
 ext4_end_bio+0x281/0x3a0 fs/ext4/page-io.c:384
 bio_endio+0x390/0x570 block/bio.c:1929
 blk_update_request+0x33a/0x710 block/blk-mq.c:1029
 scsi_end_request+0x4b/0x4c0 drivers/scsi/scsi_lib.c:671
 scsi_io_completion+0x7f/0x1d0 drivers/scsi/scsi_lib.c:1112
 scsi_finish_command+0x1c7/0x1e0 drivers/scsi/scsi.c:198
 scsi_complete+0x155/0x4d0 drivers/scsi/scsi_lib.c:1594
 blk_complete_reqs block/blk-mq.c:1235 [inline]
 blk_done_softirq+0x77/0xb0 block/blk-mq.c:1240
 handle_softirqs+0xcc/0x2a0 kernel/softirq.c:645
 __do_softirq kernel/softirq.c:679 [inline]
 invoke_softirq kernel/softirq.c:519 [inline]
 __irq_exit_rcu+0x44/0xe0 kernel/softirq.c:758
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0x74/0x80 arch/x86/kernel/apic/apic.c:1062
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
 __preempt_count_dec_and_test arch/x86/include/asm/preempt.h:123 [inline]
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:211 [inline]
 _raw_spin_unlock_irqrestore+0x1a/0x30 kernel/locking/spinlock.c:221
 spin_unlock_irqrestore include/linux/spinlock.h:425 [inline]
 __uart_port_unlock_irqrestore include/linux/serial_core.h:622 [inline]
 univ8250_console_device_unlock+0x36/0x40 drivers/tty/serial/8250/8250_core.c:420
 nbcon_emit_one kernel/printk/nbcon.c:1165 [inline]
 nbcon_kthread_func+0x595/0x690 kernel/printk/nbcon.c:1271
 kthread+0x223/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff88810064ad98 of 8 bytes by task 9287 on cpu 0:
 xas_find_chunk include/linux/xarray.h:1752 [inline]
 xas_find_marked+0x211/0x650 lib/xarray.c:1513
 find_get_entry mm/filemap.c:2087 [inline]
 filemap_get_folios_tag+0xf7/0x400 mm/filemap.c:2353
 __filemap_fdatawait_range mm/filemap.c:523 [inline]
 filemap_fdatawait_keep_errors+0x6c/0x190 mm/filemap.c:626
 wait_sb_inodes fs/fs-writeback.c:2935 [inline]
 sync_inodes_sb+0x424/0x4d0 fs/fs-writeback.c:3068
 sync_inodes_one_sb+0x3d/0x50 fs/sync.c:77
 __iterate_supers+0x205/0x360 fs/super.c:980
 iterate_supers+0x1f/0x30 fs/super.c:996
 ksys_sync fs/sync.c:102 [inline]
 __ia32_sys_sync+0x5c/0xb0 fs/sync.c:111
 x64_sys_call+0x1e8b/0x2550 arch/x86/include/generated/asm/syscalls_64.h:163
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x000000038eff0000 -> 0x000000000eff0000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 9287 Comm: syz.4.2781 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
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