In what circumstances will a prisoner challenge the execution of his sentence under Section 2255 of the Criminal Code?

In contrast, a prisoner challenging the manner, location, or conditions of that sentence's execution must bring a petition for writ of habeas corpus under 28 U.S.C. 2241 in the district where the petitioner is in custody. Stephens, 464 F.3d at 897; Hernandez v. Campbell, 204 F.3d 861, 864-65 (9th Cir. 2000) (per curiam). "The general rule is that a motion under 28 U.S.C. 2255 is the exclusive means by which a federal prisoner may test the legality of his detention, and that restrictions on the availability of a 2255 motion cannot be avoided through a petition under 28 U.S.C. 2241." Stephens, 464 F.3d at 897 (citations omitted).