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BUG: KCSAN: data-race in __mpage_writepage / truncate_setsize

write to 0xffff88810aa43a28 of 8 bytes by task 7457 on cpu 1:
 i_size_write include/linux/fs.h:886 [inline]
 truncate_setsize+0x2a/0xc0 mm/truncate.c:765
 fat_setattr+0x8d8/0x9f0 fs/fat/file.c:550
 notify_change+0xa5c/0xad0 fs/attr.c:482
 do_truncate+0xfa/0x140 fs/open.c:65
 handle_truncate fs/namei.c:3216 [inline]
 do_open fs/namei.c:3561 [inline]
 path_openat+0x1840/0x1b60 fs/namei.c:3714
 do_filp_open+0x105/0x220 fs/namei.c:3741
 do_sys_openat2+0xb5/0x2a0 fs/open.c:1310
 do_sys_open fs/open.c:1326 [inline]
 __do_sys_openat fs/open.c:1342 [inline]
 __se_sys_openat fs/open.c:1337 [inline]
 __x64_sys_openat+0xef/0x110 fs/open.c:1337
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff88810aa43a28 of 8 bytes by task 7455 on cpu 0:
 i_size_read include/linux/fs.h:864 [inline]
 __mpage_writepage+0xb8/0xda0 fs/mpage.c:469
 write_cache_pages+0x443/0xa30 mm/page-writeback.c:2472
 mpage_writepages+0x6e/0xe0 fs/mpage.c:664
 fat_writepages+0x20/0x30 fs/fat/inode.c:200
 do_writepages+0x1db/0x350 mm/page-writeback.c:2581
 filemap_fdatawrite_wbc+0xd6/0xf0 mm/filemap.c:388
 __filemap_fdatawrite_range mm/filemap.c:421 [inline]
 file_write_and_wait_range+0xf2/0x190 mm/filemap.c:777
 __generic_file_fsync+0x48/0x140 fs/libfs.c:1132
 fat_file_fsync+0x48/0x100 fs/fat/file.c:191
 vfs_fsync_range+0x107/0x120 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2885 [inline]
 generic_file_write_iter+0x18d/0x1c0 mm/filemap.c:3936
 call_write_iter include/linux/fs.h:2189 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x468/0x760 fs/read_write.c:584
 ksys_write+0xe8/0x1a0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x000000000003a000 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7455 Comm: syz-executor.4 Not tainted 6.2.0-rc5-syzkaller-00047-g7c46948a6e9c-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
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