In that case, you're responsible for your entire loan balance. (studentloanhero.com)
If you're on the 10 - year Standard Repayment Plan, you'll have paid your entire loan balance by the time you've made enough payments to qualify for PSLF (credible.com)
For federal student loans, the first consequence of default is that «acceleration» kicks in, meaning that the entire loan balance is due immediately. (valuepenguin.com)