Re: [PATCH] x86/kbuild: enable modversions for symbols exported from asm

[Stanislav Kozina]

> > > > The question is how to provide a similar guarantee if a different way?
> > > As a tool to aid distro reviewers, modversions has some value, but the
> > > debug info parsing tools that have been mentioned in this thread seem
> > > superior (not that I've tested them).
> > On the other hand the big advantage of modversions is that it also
> > verifies the checksum during runtime (module loading). In other words, I
> > believe that any other solution should still generate some form of
> > checksum/watermark which can be easily checked for compatibility on
> > module load.
> > It should not be hard to add to the DWARF based tools though. We'd just
> > parse DWARF data instead of the C code.
> A runtime check is still done, with per-module vermagic which distros
> can change when they bump the ABI version. Is it really necessary to
> have more than that (i.e., per-symbol versioning)?

From my point of view, it is. We need to allow changing ABI for some 
modules while maintaining it for others.
In fact I think that there should be version not only for every exported 
symbol (in the EXPORT_SYMBOL() sense), but also for every public type 
(in the sense of eg. structure defined in the public header file).

Thanks,
-Stanislav