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BUG: KCSAN: data-race in __writeback_single_inode / xas_clear_mark

read to 0xffff888125dded44 of 4 bytes by task 12348 on cpu 0:
 mapping_tagged include/linux/fs.h:521 [inline]
 __writeback_single_inode+0x367/0x8e0 fs/fs-writeback.c:1499
 writeback_single_inode+0x232/0x310 fs/fs-writeback.c:1562
 sync_inode fs/fs-writeback.c:2599 [inline]
 sync_inode_metadata+0x74/0xa0 fs/fs-writeback.c:2619
 __generic_file_fsync+0x122/0x190 fs/libfs.c:1011
 ext4_sync_file+0x48e/0xb00 fs/ext4/fsync.c:120
 vfs_fsync_range+0x82/0x150 fs/sync.c:197
 generic_write_sync include/linux/fs.h:2853 [inline]
 ext4_file_write_iter+0x45b/0xa00 fs/ext4/file.c:279
 call_write_iter include/linux/fs.h:1895 [inline]
 do_iter_readv_writev+0x487/0x5b0 fs/read_write.c:693
 do_iter_write fs/read_write.c:970 [inline]
 do_iter_write+0x13b/0x3c0 fs/read_write.c:951
 vfs_iter_write+0x5c/0x80 fs/read_write.c:983
 iter_file_splice_write+0x4c0/0x7f0 fs/splice.c:746
 do_splice_from fs/splice.c:848 [inline]
 direct_splice_actor+0xa0/0xc0 fs/splice.c:1020
 splice_direct_to_actor+0x215/0x510 fs/splice.c:975
 do_splice_direct+0x161/0x1e0 fs/splice.c:1063

write to 0xffff888125dded44 of 4 bytes by interrupt on cpu 1:
 xa_mark_clear lib/xarray.c:74 [inline]
 xas_clear_mark lib/xarray.c:917 [inline]
 xas_clear_mark+0x1a0/0x1d0 lib/xarray.c:898
 __xa_clear_mark+0xd3/0x100 lib/xarray.c:1713
 test_clear_page_writeback+0x449/0x790 mm/page-writeback.c:2731
 end_page_writeback+0x9e/0x190 mm/filemap.c:1338
 ext4_finish_bio+0x40d/0x520 fs/ext4/page-io.c:110
 ext4_end_bio+0xd2/0x310 fs/ext4/page-io.c:334
 bio_endio+0x3a8/0x4f0 block/bio.c:1818
 req_bio_endio block/blk-core.c:242 [inline]
 blk_update_request+0x427/0x7b0 block/blk-core.c:1462
 scsi_end_request+0x6b/0x3e0 drivers/scsi/scsi_lib.c:579
 scsi_io_completion+0x11d/0xc80 drivers/scsi/scsi_lib.c:963
 scsi_finish_command+0x280/0x380 drivers/scsi/scsi.c:228
 scsi_softirq_done+0x259/0x280 drivers/scsi/scsi_lib.c:1477
 blk_done_softirq+0x1eb/0x250 block/blk-softirq.c:37

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 12337 Comm: udevd Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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