Musannaf Ibn Abi Shayba 3:1577

Abu Bakr narrated to us, he said: Hushaym narrated to us, he said: Khalid and Mansur informed us, from Ibn Sirin, from Yahya ibn al-Jazzar, that Ibn Mas’ud prayed while there was dung and blood on his stomach. He said: So he did not repeat the prayer.