Kernel issue or libvirt issue? Where to report?

Hi, After upgrading the VM host (os + kernel) a VM client can no longer use a pass-through USB device. The syslog of the VM host is flooded with: nov 08 19:59:46 vmhost kernel: usb 1-3: usbfs: process 1729 (qemu-system-x86) did not claim interface 1 before use Because of the upgrade the vm host has gotten both a new kernel version and a new libvirt verion. The vm client has not been touched. Before I waste everyone's time on an incorrect bug report, would you say I file this with libvirt or with the openSUSE kernel (the o.s. of the vmhost)? Thanks! Koos