If someone swears an oath while in ihram, what is its expiation?

Hazrat Mujahid says that if a person takes an oath while in the state of Ihram, there is nothing (no penalty) upon him.

12797 - Abu Bakr narrated to us, he said: Waki‘ narrated to us from Sufyan from Al-Minhāl from Abu Wā’il who said: An oath.

Hazrat Hassan bin Abi Yahya narrates that I heard from Hazrat Ikrimah when a person asked him: "I have taken an oath that if I do not have intercourse with my slave-girl, I will make my wife perform ten Hajj?" He replied: "If you fulfill this oath, it will be for Satan; go away, this is an oath, pay its expiation."

Hasan and Hazrat Jabir bin Zaid say that when a person, while in the state of Ihram for Hajj, takes an oath, he should offer expiation for his oath.

It was asked from Hazrat Ata that if a person swears an oath saying, "A thousand Hajj are obligatory upon me," he replied that he must pay the expiation for the oath.

Ibrahim was asked about a person who swears an oath that he is in ihram with a thousand pilgrimages. He replied: He should perform as many pilgrimages as he is able.