Question: What role is shared by both Kevin Cronin and Boots Riley?

Context paragraphs:
I Do' Wanna Know: "I Do' Wanna Know" is a song written by Kevin Cronin that was the lead single from REO Speedwagon's 1984 album "Wheels Are Turnin'".  It was more of a rocker reminiscent of the songs REO Speedwagon had released in the 1970s than the ballads the band had been successful with in the early 1980s.  It had limited success on popular music charts, which was blamed for delaying sales of the album until the release of the follow up single, the ballad "Can't Fight This Feeling."  The video to the song was nominated for several awards.

Sean Cronin (Wisconsin politician): Sean Cronin is a former meteorologist and political candidate in Wisconsin.  His brother, Kevin Cronin, is the lead singer of R.E.O. Speedwagon.

Caught in the Game: Caught in the Game is the fourth album by American rock band Survivor, released in September 1983.  It features guest appearances by Mr. Mister's Richard Page and REO Speedwagon's Kevin Cronin.  It is the band's last album to-date to feature lead vocalist Dave Bickler, who left due to vocal surgery; despite the fact that he rejoined the band between 1993 and 2000, and again in 2013.

Don't Let Him Go: "Don't Let Him Go" is a song written by Kevin Cronin.  It was originally released as the opening song for REO Speedwagon's #1 album "Hi Infidelity".  It was also released as a single, reaching #24 on the "Billboard" Hot 100 chart.  "Don't Let Him Go" has appeared on several REO Speedwagon greatest hits albums.

Boots Riley: Raymond Lawrence "Boots" Riley (born 1971), better known by his stage name Boots Riley, is an American rapper, producer and film director best known as the lead vocalist of The Coup and Street Sweeper Social Club.  Riley is known for his energetic, charismatic, "punk"-like presence on-stage, combined with dancing

Kevin Cronin: Kevin Patrick Cronin (born October 6, 1951) is the lead vocalist, rhythm guitarist, and occasional pianist for the American rock band, REO Speedwagon.  REO Speedwagon had several hits on the "Billboard" Hot 100 throughout the 1980s, including two chart-toppers written by Cronin: "Keep on Loving You" (1981) and "Can't Fight This Feeling" (1985).

R.E.O. Speedwagon (album): R.E.O. Speedwagon is the debut studio album by American rock band REO Speedwagon.  Released in 1971, it was the only album recorded with singer Terry Luttrell until Kevin Cronin joined the band for "R.E.O./T.W.O." This album concluded with one progressive rock song unlike the later arena rock songs that made them famous.

Ridin' the Storm Out: Ridin' the Storm Out is the third studio album by REO Speedwagon, released in 1973.  It peaked at number 171 on the Billboard 200 chart in 1981, and reaching platinum status in 1989.  It was the first album to feature Mike Murphy on vocals.  The sessions started out with Kevin Cronin, but he left the band before the album was finished, due to creative differences.  The title track would later become a hit for the band on their live album, after Cronin had returned to the band.  The song refers to the band being stuck in a harsh winter blizzard after a show in Boulder, Colorado at a bar named Tulagi's (now closed).

I Needed to Fall: "I Needed to Fall" is a song written by Kevin Cronin and performed by REO Speedwagon for their 2007 album, "Find Your Own Way Home".  The song was released as the first single from the album, and charted on the Adult Contemporary chart at #25.

R.E.O. (album): R.E.O. is the sixth studio album by REO Speedwagon, released in 1976.  It peaked at number 159 on the Billboard 200 chart in 1976, It marked the return of Kevin Cronin to the band after a four-year absence.  Five of the songs ("Keep Pushin", "Any Kind of Love", "(Only A) Summer Love", "(I Believe) Our Time Is Gonna Come", and "Flying Turkey Trot") were featured on the band's subsequent live album, "".  Many fans refer to the album as "C.O.W." (or simply "COW") due to the background of the cover art.

Supporting paragraphs: Kevin Cronin Boots Riley
Answer: lead vocalist