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Message-ID: <9a8748490511231004l36edcf57mf0fb63c4a9e17f49@mail.gmail.com>
Date: Wed, 23 Nov 2005 19:04:41 +0100
From: Jesper Juhl <jesper.juhl@gmail.com>
To: Bill Davidsen <davidsen@tmr.com>
Subject: Re: Over-riding symbols in the Kernel causes Kernel Panic
Cc: Ashutosh Naik <ashutosh.lkml@gmail.com>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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	 <4384AAED.3070804@tmr.com>
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On 11/23/05, Bill Davidsen <davidsen@tmr.com> wrote:
> Ashutosh Naik wrote:
> > Hi,
> >
> > I made e1000 ( or for that matter anything) a part of the 2.6.15-rc1
> > kernel and booted the kernel. Next I compiled e1000 as a module (
> > e1000.ko ), and tried to insmod it into the kernel( which already had
> > e1000 a compiled as a part of the kernel). I observed that
> > /proc/kallsyms contained two copies of all the symbols exported by
> > e1000, and I also got a Kernel Panic on the way.
> >
> > Is this behaviour natural and desirable ?
>
> No, trying to insert a module into a kernel built with the functionality
> compiled in is a vile perverted act, and probably illegal in Republican
> states! ;-)
>
> The other day I mentioned that reiser4 will find bugs because people
> will do bizarre things with it when it is more widely used. I think you
> have hit a "no one would ever do that" bug in the module loader, and
> demonstrated my point in the process.
>
> The panic isn't desirable, but I'm not sure what "correct behaviour"
> would be, I can't imagine that this is intended to work. The issues of
> removing such a module gracefully are significant.

Wouldn't the desired behaviour be that when the kernel attempts to
load a module it checks if it is already present build-in and if so
simply refuse to load it at all?

--
Jesper Juhl <jesper.juhl@gmail.com>
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