Attribution goes to Petr Vandrovec for finding and solving this one. You
probably read the mail you were cc'ed on, so I'll just mention that this
patch makes sure that the irq disabling and enabling is perfectly
balanced in the probing path. I've also looked at the multiple irq chain
problem you mentioned, and as far as I can see we are never touching the
2nd chain from within the first one. So should be ok.

I'm also including the unexpected interrupt prinkt removal.