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BUG: KCSAN: data-race in find_get_pages_range_tag / xas_init_marks

read-write to 0xffff88810d7866b8 of 8 bytes by task 18788 on cpu 0:
 instrument_read_write include/linux/instrumented.h:57 [inline]
 __instrument_read_write_bitop include/asm-generic/bitops/instrumented-non-atomic.h:81 [inline]
 __test_and_clear_bit include/asm-generic/bitops/instrumented-non-atomic.h:109 [inline]
 node_clear_mark lib/xarray.c:100 [inline]
 xas_clear_mark lib/xarray.c:911 [inline]
 xas_init_marks+0x17e/0x310 lib/xarray.c:944
 xas_store+0x1f7/0xcb0 lib/xarray.c:806
 page_cache_delete_batch mm/filemap.c:337 [inline]
 delete_from_page_cache_batch+0x3e4/0x800 mm/filemap.c:358
 truncate_inode_pages_range+0x482/0xf20 mm/truncate.c:366
 truncate_inode_pages mm/truncate.c:476 [inline]
 truncate_pagecache mm/truncate.c:839 [inline]
 truncate_setsize+0x97/0xc0 mm/truncate.c:864
 fat_setattr+0x623/0x740 fs/fat/file.c:536
 notify_change+0x7b3/0xa50 fs/attr.c:336
 do_truncate fs/open.c:64 [inline]
 do_sys_ftruncate+0x39f/0x3e0 fs/open.c:195
 __do_sys_ftruncate fs/open.c:205 [inline]
 __se_sys_ftruncate fs/open.c:203 [inline]
 __x64_sys_ftruncate+0x2f/0x40 fs/open.c:203
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810d7866b8 of 8 bytes by task 18784 on cpu 1:
 xas_find_chunk include/linux/xarray.h:1660 [inline]
 xas_next_marked include/linux/xarray.h:1691 [inline]
 find_get_pages_range_tag+0x35c/0x600 mm/filemap.c:2094
 pagevec_lookup_range_tag+0x37/0x50 mm/swap.c:1161
 write_cache_pages+0x1e9/0x7f0 mm/page-writeback.c:2203
 mpage_writepages+0x6d/0x120 fs/mpage.c:714
 fat_writepages+0x20/0x30 fs/fat/inode.c:205
 do_writepages+0x7b/0x150 mm/page-writeback.c:2352
 __filemap_fdatawrite_range+0x19d/0x1d0 mm/filemap.c:422
 file_write_and_wait_range+0x9f/0x120 mm/filemap.c:761
 __generic_file_fsync+0x48/0x140 fs/libfs.c:1074
 fat_file_fsync+0x48/0x100 fs/fat/file.c:190
 vfs_fsync_range+0x107/0x120 fs/sync.c:200
 generic_write_sync include/linux/fs.h:2723 [inline]
 generic_file_write_iter+0x103/0x130 mm/filemap.c:3476
 call_write_iter include/linux/fs.h:1887 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x617/0x690 fs/read_write.c:605
 ksys_write+0xce/0x180 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write fs/read_write.c:667 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:667
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 18784 Comm: syz-executor.5 Not tainted 5.10.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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