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BUG: KCSAN: data-race in __xa_clear_mark / filemap_write_and_wait_range

write to 0xffff888105d2c8ac of 4 bytes by interrupt on cpu 1:
 xa_mark_clear lib/xarray.c:75 [inline]
 xas_clear_mark lib/xarray.c:921 [inline]
 __xa_clear_mark+0x2a2/0x2c0 lib/xarray.c:1917
 test_clear_page_writeback+0x2f1/0x640 mm/page-writeback.c:2739
 end_page_writeback+0xd7/0x1b0 mm/filemap.c:1460
 ext4_finish_bio+0x3e2/0x430 fs/ext4/page-io.c:143
 ext4_end_bio+0x1ba/0x310 fs/ext4/page-io.c:364
 bio_endio+0x21d/0x300 block/bio.c:1451
 req_bio_endio block/blk-core.c:265 [inline]
 blk_update_request+0x435/0xa30 block/blk-core.c:1456
 scsi_end_request+0x4d/0x450 drivers/scsi/scsi_lib.c:570
 scsi_io_completion+0xd3/0xf10 drivers/scsi/scsi_lib.c:970
 scsi_finish_command+0x238/0x250 drivers/scsi/scsi.c:214
 scsi_softirq_done+0xd1/0x360 drivers/scsi/scsi_lib.c:1450
 blk_complete_reqs block/blk-mq.c:576 [inline]
 blk_done_softirq+0x69/0x90 block/blk-mq.c:581
 __do_softirq+0x12c/0x275 kernel/softirq.c:345
 invoke_softirq kernel/softirq.c:221 [inline]
 __irq_exit_rcu+0xaa/0xb0 kernel/softirq.c:422
 common_interrupt+0x3e/0x90 arch/x86/kernel/irq.c:240
 asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:623

read to 0xffff888105d2c8ac of 4 bytes by task 6566 on cpu 0:
 xa_marked include/linux/xarray.h:418 [inline]
 mapping_tagged include/linux/fs.h:490 [inline]
 __filemap_fdatawrite_range mm/filemap.c:420 [inline]
 filemap_write_and_wait_range+0x1d8/0x390 mm/filemap.c:657
 __iomap_dio_rw+0x40a/0xa10 fs/iomap/direct-io.c:525
 iomap_dio_rw+0x30/0x70 fs/iomap/direct-io.c:641
 ext4_dio_write_iter fs/ext4/file.c:551 [inline]
 ext4_file_write_iter+0xa04/0x11d0 fs/ext4/file.c:661
 call_write_iter include/linux/fs.h:1977 [inline]
 do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
 do_iter_write+0x112/0x4c0 fs/read_write.c:866
 vfs_iter_write+0x4c/0x70 fs/read_write.c:907
 iter_file_splice_write+0x40a/0x750 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:936
 splice_direct_to_actor+0x345/0x650 fs/splice.c:891
 do_splice_direct+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x773/0xda0 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1325 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1311
 do_syscall_64+0x34/0x50 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 6566 Comm: syz-executor.0 Not tainted 5.12.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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