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BUG: KCSAN: data-race in find_get_pages_range_tag / xas_clear_mark

write to 0xffff888125a27b30 of 8 bytes by interrupt on cpu 1:
 __test_and_clear_bit include/asm-generic/bitops-instrumented.h:213 [inline]
 node_clear_mark lib/xarray.c:99 [inline]
 xas_clear_mark+0x11a/0x1d0 lib/xarray.c:907
 __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
 page_endio+0x94/0x280 mm/filemap.c:1369
 mpage_end_io+0x14c/0x1c0 fs/mpage.c:54
 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
 blk_mq_end_request+0x3f/0x2b0 block/blk-mq.c:568
 lo_complete_rq+0x136/0x1a0 drivers/block/loop.c:485
 blk_done_softirq+0x1eb/0x250 block/blk-softirq.c:37
 __do_softirq+0x115/0x33f kernel/softirq.c:292
 run_ksoftirqd+0x46/0x60 kernel/softirq.c:603
 smpboot_thread_fn+0x37d/0x4a0 kernel/smpboot.c:165
 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253

read to 0xffff888125a27b30 of 8 bytes by task 7410 on cpu 0:
 xas_find_chunk include/linux/xarray.h:1590 [inline]
 xas_next_marked include/linux/xarray.h:1620 [inline]
 find_get_pages_range_tag+0x1c2/0x670 mm/filemap.c:1924
 pagevec_lookup_range_tag+0x45/0x70 mm/swap.c:1054
 __filemap_fdatawait_range+0xdc/0x1d0 mm/filemap.c:517
 file_write_and_wait_range+0x134/0x160 mm/filemap.c:785
 __generic_file_fsync+0x59/0x190 fs/libfs.c:1000
 fat_file_fsync+0x58/0x120 fs/fat/file.c:199
 vfs_fsync_range+0x82/0x150 fs/sync.c:197
 generic_write_sync include/linux/fs.h:2853 [inline]
 generic_file_write_iter+0x318/0x390 mm/filemap.c:3469
 call_write_iter include/linux/fs.h:1895 [inline]
 new_sync_write+0x388/0x4a0 fs/read_write.c:483
 __vfs_write+0xb1/0xc0 fs/read_write.c:496
 vfs_write fs/read_write.c:558 [inline]
 vfs_write+0x18a/0x390 fs/read_write.c:542
 ksys_write+0xd5/0x1b0 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __x64_sys_write+0x4c/0x60 fs/read_write.c:620

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7410 Comm: syz-executor.5 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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