Loopback qrexec connection not supported

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.

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.


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).

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