Loopback qrexec connection not supported

User Support
1

Hi,
I have a problem with sys-usb and attaching a USB device to it. I am getting this error message:

Sep 24 15:38:43 dom0 qrexec-policy-daemon[2184]: qrexec: qubes.USB+3-1: sys-usb -> sys-usb: denied: loopback qrexec connection not supported

My sys-usb is a disposal one. Any idea how to debug this? I can attach this device to any VM except sys-usb.

2

I think you don’t need to “attach” a USB device to sys-usb! It is available directly. Try running lsusb in sys-usb after inserting the USB device. And sudo dmesg will show the details, like the device name (ex. sdb) and partitions.

3

That’s right, the error message is complaining about the attempt to attach a device from sys-usb to sys-usb (which would be a connection that “loops back” to where it started).