Error message
xillybus: Bad interrupt message. Stopping.Meaning
Each hardware interrupt from the FPGA to host is accompanied with information about the reason for the interrupt. This error is issued when this information came severely malformed, to the extent that it can't relate to interrupts anymore. Effectively, the driver stops reacting to the FPGA.
Recommended action
This is a severe unexpected fatal condition, and it should be reported.
To get Xillybus working again, power the computer off, reconfigure the FPGA and power the computer on again.