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BUG: KCSAN: data-race in __xa_clear_mark / xas_find_marked

read-write to 0xffff88811ace1900 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:1016
 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:1222 [inline]
 blk_done_softirq+0x77/0xb0 block/blk-mq.c:1227
 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
 common_interrupt+0x83/0x90 arch/x86/kernel/irq.c:273
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:665
 __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
 unlock_hrtimer_base kernel/time/hrtimer.c:1042 [inline]
 hrtimer_start_range_ns_user+0x12e/0x150 kernel/time/hrtimer.c:1629
 hrtimer_start_expires_user include/linux/hrtimer.h:247 [inline]
 hrtimer_sleeper_start_expires kernel/time/hrtimer.c:2356 [inline]
 do_nanosleep+0x73/0x360 kernel/time/hrtimer.c:2433
 hrtimer_nanosleep+0xf2/0x290 kernel/time/hrtimer.c:2482
 common_nsleep+0x62/0x80 kernel/time/posix-timers.c:1360
 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1406 [inline]
 __se_sys_clock_nanosleep+0x223/0x260 kernel/time/posix-timers.c:1383
 __x64_sys_clock_nanosleep+0x55/0x70 kernel/time/posix-timers.c:1383
 x64_sys_call+0x244d/0x2550 arch/x86/include/generated/asm/syscalls_64.h:231
 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

read to 0xffff88811ace1900 of 8 bytes by task 5063 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_write_and_wait_range+0x1f5/0x370 mm/filemap.c:692
 ext4_dio_write_iter fs/ext4/file.c:694 [inline]
 ext4_file_write_iter+0xc93/0x1020 fs/ext4/file.c:794
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x57f/0x9a0 fs/read_write.c:687
 ksys_write+0xdc/0x1a0 fs/read_write.c:739
 __do_sys_write fs/read_write.c:750 [inline]
 __se_sys_write fs/read_write.c:747 [inline]
 __x64_sys_write+0x40/0x50 fs/read_write.c:747
 x64_sys_call+0x154e/0x2550 arch/x86/include/generated/asm/syscalls_64.h:2
 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: 0x00000000fffffff0 -> 0x00000000ffff0000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 5063 Comm: syz.4.390 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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