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BUG: KCSAN: data-race in vfs_fsync_range / writeback_single_inode

write to 0xffff88810683a288 of 8 bytes by task 25740 on cpu 1:
 writeback_single_inode+0x10e/0x4a0 fs/fs-writeback.c:1743
 sync_inode_metadata+0x56/0x80 fs/fs-writeback.c:2808
 __generic_file_fsync+0xf9/0x140 fs/libfs.c:1451
 fat_file_fsync+0x4c/0x100 fs/fat/file.c:191
 vfs_fsync_range+0x111/0x120 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2653 [inline]
 generic_file_write_iter+0x191/0x1c0 mm/filemap.c:4043
 do_iter_write+0x4ad/0x770 fs/read_write.c:860
 vfs_iter_write+0x56/0x70 fs/read_write.c:901
 iter_file_splice_write+0x462/0x7e0 fs/splice.c:736
 do_splice_from fs/splice.c:933 [inline]
 direct_splice_actor+0x8a/0xb0 fs/splice.c:1142
 splice_direct_to_actor+0x31d/0x690 fs/splice.c:1088
 do_splice_direct+0x10d/0x190 fs/splice.c:1194
 do_sendfile+0x3c4/0x980 fs/read_write.c:1254
 __do_sys_sendfile64 fs/read_write.c:1322 [inline]
 __se_sys_sendfile64 fs/read_write.c:1308 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1308
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff88810683a288 of 8 bytes by task 25742 on cpu 0:
 vfs_fsync_range+0xa2/0x120 fs/sync.c:186
 generic_write_sync include/linux/fs.h:2653 [inline]
 generic_file_write_iter+0x191/0x1c0 mm/filemap.c:4043
 do_iter_write+0x4ad/0x770 fs/read_write.c:860
 vfs_iter_write+0x56/0x70 fs/read_write.c:901
 iter_file_splice_write+0x462/0x7e0 fs/splice.c:736
 do_splice_from fs/splice.c:933 [inline]
 direct_splice_actor+0x8a/0xb0 fs/splice.c:1142
 splice_direct_to_actor+0x31d/0x690 fs/splice.c:1088
 do_splice_direct+0x10d/0x190 fs/splice.c:1194
 do_sendfile+0x3c4/0x980 fs/read_write.c:1254
 __do_sys_sendfile64 fs/read_write.c:1322 [inline]
 __se_sys_sendfile64 fs/read_write.c:1308 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1308
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0000000000000005 -> 0x0000000000000084

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 25742 Comm: syz-executor.5 Not tainted 6.7.0-rc1-syzkaller-00012-g9bacdd8996c7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
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