Secondary sources commonly name Niani, the Mali Empire's capital, as both his birthplace and place of death, but no surviving primary Arabic source states either directly; it is an inference from his seat of power.
What would resolve this A surviving Malian court record, or a direct statement in the Arabic geographic sources (Ibn Battuta, al-Umari, Ibn Khaldun) naming his birthplace or place of death; the surviving sources establish his reign and pilgrimage but not these two facts directly.
OpenMedieval West African and Mali Empire historyWikipedia: Mansa Musa (pilgrimage source)