syzbot

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BUG: KCSAN: data-race in __xa_clear_mark / xas_find_marked

read-write to 0xffff888106613b48 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+0x18f/0x4a0 mm/page-writeback.c:3085
 folio_end_writeback+0x74/0x1f0 mm/filemap.c:1634
 end_buffer_async_write+0x1ca/0x230 fs/buffer.c:409
 end_bio_bh_io_sync+0x76/0xa0 fs/buffer.c:2772
 bio_endio+0x369/0x410 block/bio.c:1645
 blk_update_request+0x368/0x860 block/blk-mq.c:981
 blk_mq_end_request+0x26/0x50 block/blk-mq.c:1143
 lo_complete_rq+0xce/0x180 drivers/block/loop.c:386
 blk_complete_reqs block/blk-mq.c:1218 [inline]
 blk_done_softirq+0x74/0xb0 block/blk-mq.c:1223
 handle_softirqs+0xbf/0x280 kernel/softirq.c:554
 do_softirq+0x5e/0x90 kernel/softirq.c:455
 __local_bh_enable_ip+0x6e/0x70 kernel/softirq.c:382
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 srcu_invoke_callbacks+0x16c/0x250 kernel/rcu/srcutree.c:1796
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3310
 worker_thread+0x51d/0x6f0 kernel/workqueue.c:3391
 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 0xffff888106613b48 of 8 bytes by task 3322 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:1994
 filemap_get_folios_tag+0x136/0x210 mm/filemap.c:2261
 __filemap_fdatawait_range mm/filemap.c:524 [inline]
 filemap_write_and_wait_range+0x1d5/0x360 mm/filemap.c:694
 filemap_write_and_wait include/linux/pagemap.h:68 [inline]
 sync_blockdev+0x35/0x50 block/bdev.c:219
 sync_filesystem+0x162/0x190 fs/sync.c:70
 generic_shutdown_super+0x46/0x220 fs/super.c:621
 kill_block_super+0x2a/0x70 fs/super.c:1710
 ext4_kill_sb+0x44/0x80 fs/ext4/super.c:7379
 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:239
 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:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xa8/0x120 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: 0x0000000000020603 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3322 Comm: syz-executor Not tainted 6.12.0-syzkaller-01892-g8f7c8b88bda4 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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EXT4-fs (loop2): unmounting filesystem 00000000-0000-0000-0000-000000000000.