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BUG: KCSAN: data-race in __mpage_writepage / truncate_setsize

read-write to 0xffff888126278a28 of 8 bytes by task 28204 on cpu 1:
 i_size_write include/linux/fs.h:905 [inline]
 truncate_setsize+0x21/0xb0 mm/truncate.c:766
 fat_setattr+0x71f/0x840 fs/fat/file.c:550
 notify_change+0x8c3/0x930 fs/attr.c:483
 do_truncate+0x116/0x150 fs/open.c:66
 handle_truncate fs/namei.c:3295 [inline]
 do_open fs/namei.c:3640 [inline]
 path_openat+0x1984/0x1d00 fs/namei.c:3791
 do_filp_open+0xf6/0x200 fs/namei.c:3818
 do_sys_openat2+0xb5/0x2a0 fs/open.c:1356
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_openat fs/open.c:1388 [inline]
 __se_sys_openat fs/open.c:1383 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1383
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff888126278a28 of 8 bytes by task 28186 on cpu 0:
 i_size_read include/linux/fs.h:883 [inline]
 __mpage_writepage+0xc3/0xdb0 fs/mpage.c:489
 write_cache_pages+0x3a1/0x760 mm/page-writeback.c:2473
 mpage_writepages+0x72/0xe0 fs/mpage.c:679
 fat_writepages+0x24/0x30 fs/fat/inode.c:200
 do_writepages+0x1c5/0x340 mm/page-writeback.c:2551
 filemap_fdatawrite_wbc+0xdb/0xf0 mm/filemap.c:390
 __filemap_fdatawrite_range mm/filemap.c:423 [inline]
 file_write_and_wait_range+0xfa/0x190 mm/filemap.c:781
 __generic_file_fsync+0x4c/0x140 fs/libfs.c:1127
 fat_file_fsync+0x4c/0x100 fs/fat/file.c:191
 vfs_fsync_range+0x10b/0x120 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2469 [inline]
 generic_file_write_iter+0x191/0x1c0 mm/filemap.c:4087
 call_write_iter include/linux/fs.h:1868 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x463/0x760 fs/read_write.c:584
 ksys_write+0xeb/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+0x42/0x50 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0000000000012000 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 28186 Comm: syz-executor.0 Not tainted 6.3.0-syzkaller-12378-gc8c655c34e33 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
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