2 Questions for you -
1. Did you do the Civil War quests already, and if you did have you sided with the Stormcloaks?
2. Is the Jarl present in the room with you and Odahviing?
I ask these because it is important that the Jarl, whoever it may be for you in the game, is in the room before you try to talk to him. Not sure why this is, but this is usually the source of this glitch in my experience. If you did do the Civil War, and sided with the Stormcloaks, the Jarl usually just sits in Jorvaskr for no reason. The way to get him out of there is to just start the first Companions quest. Make sure he is no longer sitting in his chair in the corner of Jorvaskr, and then you should be able to continue when he is in the room with Odahviing.
If this doesn't apply to you I'm gonna do some more research!