What does it mean that the customs has written the old passport visa on the passport and drawn a line on the time limit?

According to the Administrative Measures of the People's Republic of China on the Issuance of Ordinary Passports and Entry-Exit Passes

Article 10 Under any of the following circumstances, an ordinary passport holder may apply to the exit-entry administration department of the public security organ of the local people's government at or above the county level where his household registration is located for a new ordinary passport:

(a) The visa page is about to run out;

(two) the validity period is less than 6 months, or the validity period is more than 6 months, but there are materials to prove that the validity period does not meet the requirements of the destination country;

(3) Other circumstances identified by the Exit-Entry Administration of the Ministry of Public Security.

Article 11 When applying for the renewal of ordinary passports, citizens shall submit the original and photocopy of ordinary passports in addition to the materials specified in Article 4 of these Measures.

When a citizen who has settled abroad returns to China for a short period of time to apply for the renewal of an ordinary passport, he shall submit it to the exit-entry administration department of the public security organ of the local people's government at or above the county level in his temporary residence, and submit the original ordinary passport, the certificate of leaving the country for settlement, and the temporary residence permit and a copy issued by the public security organ in his temporary residence.