[Qemu-devel] one issue about usb passsthrough devices

[linzhecheng]

Hi, all
A found a problem about libusb, the reproducing steps are as followed:
1. start up a vm with host-usb devices
2. kill -9 `pgrep qemu`
We can not see the usb device on host any more, I think this is because qemu 
has no chance to release
resources to kernel in this case. How can we recover environment if we 
encounter this problem?