sleep indefinitely in wait_event_interruptible(vt_event_waitqueue, vw->done);

[#1]

An i.MX50 customer encountered such kernel bug recently. Android UI has no response, because the suspend work queue is blocked:

    suspend

      pm_suspend

        enter_state

          suspend_prepare / suspend_finish

            pm_prepare_console / pm_restore_console

              vt_move_to_console

                vt_waitactive

                  vt_event_wait

                    wait_event_interruptible

Confimed the same bug can also happen on imx6SL which is running linux 3.0.35.

e.g. by echo standby/mem > /sys/power/state

It takes over thousand suspend/resume cycles to reproduce the problem.

The bug fix has been merged since linux 3.6:

commit a7b12929be6cc55eab2dac3330fa9f5984e12dda