[Qemu-block] USB Device is not stable, Cannot use it with long time

[Lying]

First, I can running my qemu guest normally,

And i can use keyboard and mouse in my VM,

But i cannot use those after one day.

And cannot find any useful log in my system.

those message is my VM state( with qemu-monitor-command ):

  Device 0.1, Port 1, Speed 1.5 Mb/s, Product G100s Gaming Keyboard, ID: hostdev0
  Device 0.2, Port 2, Speed 1.5 Mb/s, Product USB Optical Mouse, ID: hostdev1
it show me qemu add device normally,But i cannot use it