Plaintiff-Appellant Billy D. Davis, federal prisoner # 80388-008, was convicted by a jury of conspiracy to distribute 50 grams or more of cocaine base in violation of 21 U.S.C. § 846. The district court’s sentence of 360 months in prison was later reduced to 262 months. Davis now appeals the dismissal of his 28 U.S.C. § 2241 petition challenging his conviction and sentence. Davis challenges the validity of our decision in Reyes-Requena v. United States, 243 F.3d 893 (5th Cir. 2001).

We review a district court’s dismissal of a § 2241 petition de novo. Padilla v. United States, 416 F.3d 424, 425 (5th Cir. 2005). A federal prisoner who seeks to challenge the legality of his conviction or sentence must generally file a § 2255 motion. Id. at 425-26. However, if the federal prisoner can show that § 2255 is “in *288 adequate or ineffective,” he may challenge the legality of his conviction or sentence in a § 2241 petition. § 2255(e); see Reyes-Requena, 248 F.3d at 901.

Davis has not shown that his claims are “based on a retroactively applicable Supreme Court decision establishing that he may have been convicted of a nonexistent offense ... that was foreclosed by circuit law at the time when the claim should have been raised in [his] trial, appeal, or first § 2255 motion.” Reyes-Requena, 248 F.3d at 904. Further, his challenge to Reyes-Requena is unavailing: One panel of this court may not overrule another panel absent an intervening en banc decision of this court or a decision of the Supreme Court, even if the panel disagrees with the prior panel’s holding. In re Entringer Bakeries, Inc., 548 F.3d 344, 348-49 (5th Cir. 2008). Accordingly, the district court’s judgment dismissing Davis’s § 2241 petition is AFFIRMED.