Re: 2.6.4, or what I still don't quite like about the new stable branch

Alex Goddard
2004-03-17T22:25:36Z

On Wed, 17 Mar 2004, Helge Hafting wrote:

> Alex Goddard wrote:
> [...]
> >
> > Safe module unloading is a very difficult problem. So much so that
> > disallowing unloading modules completely has been discussed in the past.
> > Digging around an lkml archive for more info on why module unloading is
> > inherently problematic, and not at all easy to do (well, not at all easy
> > to do well) is recommended.
>
> Safe unloading is hard for a few oddball modules that probably shouldn't
> be modules at all but rather be part of some larger module. Is it necessary
> to have modules for various parts of iptables, instead of stuffing
> everything in a big "ipv4" module?

That is not the impression I got from this post:
http://marc.theaimsgroup.com/?l=linux-kernel&m=104554480315013&w=2

This thread is the other one that came to mind:
http://marc.theaimsgroup.com/?l=linux-kernel&m=105915495603446&w=2

In one post in the thread spawned by the second URL's post, Alan Cox
suggests a plan vaguely similar to what you outlined below what I've
quoted (ie: a MODULE_UNLOADABLE flag or something for those modules that
_can_ be easily unloaded).

However, the general impression I get from that thread on removing module
refcounting is that in general unloading modules is tricky. Not
unsolvable. Just tricky.

--
Alex Goddard
agoddard at purdue dot edu