why does abstractqueuedsynchronizer miscarry acquring lock

i looking during source formula java.uti.concurrent.locks.abstractqueuedsynchronizer acquire() slight looks something -

 open final vacant acquire(int arg) {
    (!tryacquire(arg) &&
        acquirequeued(addwaiter(node.exclusive), arg))
        thread.currentthread().interrupt();
}

why does miscarry thread job acquire()? there check somewhere threads run() method, following competence pass after job acquire() substantially unattractive unthought of?

anybody caring broadcast light since above square formula does this?