Re: [kernel-abi] symbol versioning vs. out-of-tree modules.

Arjan van de Ven
2008-09-24T21:05:26Z

On Wed, 24 Sep 2008 17:07:59 +0200
"Paweł Sikora" <pluto@agmk.net> wrote:

> Hi All,
>
> with out-of-tree kernel modules we (users and linux distributions)
> have a problem - with every frequent kernel release we need
> to rebuild them all due to vermagic and possible abi changes.
> this leads to lot of useless work (bumping rpm specs releases,
> preparing rpm packages and so on).
>
> naturally we could workaround the modprobe vermagic errors
> but we currently can't detect the big-bang kernel abi changes.
> e.g., some kernel function changes its parameter list while
> the exported function(symbol) name still staying unchanged.
> finally we get a modprobe-big-bang.
>
> in fact, we can't use a c++ symbol name mangling to avoid
> such problems but kernel build system could use a linker script
> to versioning symbols (like glibc/libgcc). during the abi change,
> kernel developers could just bump the symbol version and
> external modules could be refused during loading with
> 'unresolved symbol' error which is imho much better solutio

if it were up to me we would remove modversions from the kernel and
just hard require an exact build of the module to the kernel; anything
else is .. at best an educated wild guess.

--
Arjan van de Ven Intel Open Source Technology Centre
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