diff --git a/db/rocksdb.go b/db/rocksdb.go
index 6c3a5a84..c399e191 100644
--- a/db/rocksdb.go
+++ b/db/rocksdb.go
@@ -1250,7 +1250,7 @@ func (d *RocksDB) packBlockInfo(block *BlockInfo) ([]byte, error) {
 		if len(b) > pl {
 			b = b[:pl]
 		} else {
-			b = append(b, make([]byte, len(b)-pl)...)
+			b = append(b, make([]byte, pl-len(b))...)
 		}
 	}
 	packed = append(packed, b...)