Re: [BUG: 2.6.26-rc3] ERROR: "____ilog2_NaN" undefined

From: Greg KH
Date: Mon Jun 09 2008 - 18:16:22 EST


On Sun, Jun 08, 2008 at 02:41:12PM +0200, Mirco Tischler wrote:
> Here's an update:
> I've contacted the gcc folks. Here is the bugzilla entry:
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36359
> We were able to trace the error down to usb_submit_urb() in
> drivers/usb/core/urb.c which calls ilog2() and the gcc falsely assumes its
> argument (urb->interval) to be zero. But as I understood they say it's the
> kernel's fault because the code depends on correct optimization what seems a
> little weird for me as incorrect optimization is a gcc bug IMHO. But I am not
> an expert and maybe I've just understood something wrong because I'm not a
> native speaker.

I'm confused how the kernel code could be at fault here.

How could it be fixed to not be at fault?

thanks,

greg k-h
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