The collision was reported at 3:12 a.m. near the Crenshaw Boulevard onramp, according to a California Highway Patrol incident log.
The pileup began when a blue Dodge Challenger and a gray Infiniti collided, the CHP said. Two of the seven vehicles involved in the crash overturned.
Whether anyone was seriously injured was unclear. News video appeared to show firefighter-paramedics transporting at least one person from the scene.
After vehicles were towed away, all lanes were reopened to traffic by 6 a.m.
The cause of the crash is under investigation.