Abu Ubaydah bin Abdullah narrates: My mother told me that Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) would put on his leather socks (khuffs) at the time of the Fajr prayer, and then would not take them off until he went to his bed.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 9206