I think you're thinking of "Immortality" by Pearl Jam being about Cobain, supposedly. "Corduroy" is about Eddie dealing with fame and hanger ons. 4/16/02 by Pearl Jam about Layne Staley. Also, I've heard "Can't Keep" off of Riot Act is about Elliott Smith. On the Live At Benaroya Hall album Eddie says "This one's for Elliott" prior to playing it on the uke.