Re: Why does insmod _not_ check for symbol redefinition ??

[Rusty Russell]

On Fri, 2005-11-25 at 10:45 +0530, Nagendra Singh Tomar wrote:
> Did'nt get any response to this one, so sending it again.
> 
> Can any of the module subsystem authors tell, why they have decided to 
> allow loading a kernel module having an EXPORTed symbol with the same name 
> as an EXPORTed  symbol in kernel proper. The safest thing would be to 
> disallow  module loading in this case, giving a "Symbol redefinition" 
> error.
> 	Allowing the module load will lead to overriding kernel functions
> which will affect modules loaded in future, that reference those 
> functions. Overall, it can have bad effects of varying severity.

Sure.  It was due to minimalism.  If you override a symbol it's
undefined behavior.  It should be fairly simple to add a check that
noone overrides a symbol.  We didn't bother checking for it because it
wasn't clear that it was problematic.

Hope that clarifies,
Rusty.
-- 
A bad analogy is like a leaky screwdriver -- Richard Braakman

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