Be careful what you petition for.
David Rhodes was convicted on drug-related charges in 1993, and sentenced to twenty years' imprisonment and ten years' supervised release. In 2010, Rhodes filed a petition challenging the Federal Bureau of Prisons' calculation of his sentence. The district court dismissed the petition as moot. Why? Because Rhodes was no longer in prison.
Rhodes' petition failed on redressability. Federal law allows a court to terminate a term of supervised release after one year, but Rhodes challenged the jail sentence he served in the past, not the supervised release he is currently serving.