upstream test error: KCSAN: data-race in __xa_clear_mark / xas_find

Kernel	Title	Rank 🛈	Count	Last	Reported	Patched	Status
upstream	upstream test error: KCSAN: data-race in __xa_clear_mark / xas_find_marked fs mm	-1	2	449d	477d	0/29	auto-obsoleted due to no activity on 2024/08/24 21:02
upstream	upstream test error: KCSAN: data-race in __xa_clear_mark / xas_find_marked (3) fs mm	-1	4	65d	166d	0/29	auto-obsoleted due to no activity on 2025/10/04 05:47
upstream	upstream test error: KCSAN: data-race in __xa_clear_mark / xas_find_marked (2) fs mm	-1	1	324d	324d	0/29	auto-obsoleted due to no activity on 2025/01/18 12:40

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BUG: KCSAN: data-race in __xa_clear_mark / xas_find_marked

read-write to 0xffff888106e976b8 of 8 bytes by task 1476 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+0xf7/0x3b0 mm/page-writeback.c:2998
 folio_end_writeback_no_dropbehind+0x6d/0x1b0 mm/filemap.c:1668
 folio_end_writeback+0x1c/0x70 mm/filemap.c:1694
 ext4_finish_bio+0x459/0x8c0 fs/ext4/page-io.c:144
 ext4_release_io_end+0x9f/0x1f0 fs/ext4/page-io.c:159
 ext4_end_io_end+0x18d/0x240 fs/ext4/page-io.c:210
 ext4_do_flush_completed_IO fs/ext4/page-io.c:290 [inline]
 ext4_end_io_rsv_work+0x151/0x1e0 fs/ext4/page-io.c:305
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3346
 worker_thread+0x582/0x770 kernel/workqueue.c:3427
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x122/0x1b0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff888106e976b8 of 8 bytes by task 3663 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:2070
 filemap_get_folios_tag+0x13b/0x210 mm/filemap.c:2338
 __filemap_fdatawait_range mm/filemap.c:533 [inline]
 filemap_fdatawait_keep_errors+0x6c/0x180 mm/filemap.c:636
 wait_sb_inodes fs/fs-writeback.c:2754 [inline]
 sync_inodes_sb+0x39c/0x440 fs/fs-writeback.c:2876
 sync_inodes_one_sb+0x3d/0x50 fs/sync.c:77
 __iterate_supers+0x110/0x220 fs/super.c:923
 iterate_supers+0x1f/0x30 fs/super.c:938
 ksys_sync+0x5c/0xe0 fs/sync.c:102
 __ia32_sys_sync+0xe/0x20 fs/sync.c:113
 x64_sys_call+0x2d1f/0x3000 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: 0xffffffffffffff80 -> 0xffffffffffc00000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3663 Comm: syz.1.333 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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