Update: Apparently the system is not entirely hung. Although the mouse and keyboard are not responsive (mouse's light is off), the system just posted another bootup message:
[1606.334337] perf: interrupt took too long (2612 > 2500), lowering kernel.perf_event_max_sample_rate to 76500
Update: Apparently the system is not entirely hung. Although the mouse and keyboard are not responsive (mouse's light is off), the system just posted another bootup message:
[1606.334337] perf: interrupt took too long (2612 > 2500), lowering kernel. perf_event_ max_sample_ rate to 76500
(1600 seconds is nearly 30 minutes.)