syzbot

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BUG: KCSAN: data-race in __xa_clear_mark / xas_find_marked

read-write to 0xffff88810686cfe0 of 8 bytes by interrupt on cpu 0:
 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:915 [inline]
 __xa_clear_mark+0xf8/0x1f0 lib/xarray.c:1957
 __folio_end_writeback+0x187/0x490 mm/page-writeback.c:3085
 folio_end_writeback+0x74/0x1f0 mm/filemap.c:1632
 mpage_write_end_io+0x27c/0x390 fs/mpage.c:65
 bio_endio+0x369/0x410 block/bio.c:1646
 blk_update_request+0x382/0x880 block/blk-mq.c:925
 blk_mq_end_request+0x26/0x50 block/blk-mq.c:1053
 lo_complete_rq+0xce/0x180 drivers/block/loop.c:386
 blk_complete_reqs block/blk-mq.c:1128 [inline]
 blk_done_softirq+0x74/0xb0 block/blk-mq.c:1133
 handle_softirqs+0xc3/0x280 kernel/softirq.c:554
 run_ksoftirqd+0x1c/0x30 kernel/softirq.c:928
 smpboot_thread_fn+0x31c/0x4c0 kernel/smpboot.c:164
 kthread+0x1d1/0x210 kernel/kthread.c:389
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

read to 0xffff88810686cfe0 of 8 bytes by task 6120 on cpu 1:
 xas_find_chunk include/linux/xarray.h:1733 [inline]
 xas_find_marked+0x216/0x660 lib/xarray.c:1370
 find_get_entry+0x54/0x390 mm/filemap.c:1992
 filemap_get_folios_tag+0x136/0x210 mm/filemap.c:2242
 __filemap_fdatawait_range mm/filemap.c:523 [inline]
 filemap_fdatawait_keep_errors+0x6a/0x180 mm/filemap.c:627
 wait_sb_inodes fs/fs-writeback.c:2673 [inline]
 sync_inodes_sb+0x3bb/0x460 fs/fs-writeback.c:2795
 sync_filesystem+0x103/0x190 fs/sync.c:64
 generic_shutdown_super+0x42/0x210 fs/super.c:621
 kill_block_super+0x2a/0x70 fs/super.c:1685
 deactivate_locked_super+0x7d/0x1c0 fs/super.c:473
 deactivate_super+0x9f/0xb0 fs/super.c:506
 cleanup_mnt+0x268/0x2e0 fs/namespace.c:1373
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1380
 task_work_run+0x13a/0x1a0 kernel/task_work.c:222
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xbe/0x130 kernel/entry/common.c:218
 do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffffffffffffff80 -> 0xffffffffffffc000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 6120 Comm: syz-executor Not tainted 6.10.0-syzkaller-12708-g2f8c4f506285 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
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