[Crash-utility] crash vs irqs

I'm having a problem with the Fedora 7 kernel 2.6.21-1.3228.fc7 for x86_64. So I am trying to use crash-4.0-4.2 to analyze the problem. (The version of crash in F7 won't work with this kernel.) Since the kernel bug appears to be in irq handline, learning more about IRQ state is important. When I use the irq command I get this error message: irq: cannot determine size of irq_desc_t Is this a bug or a known limitation of crash?