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SubjectRe: inconsistent kallsyms data [2.6.11-mm2]
Paulo Marques wrote:
> [...]
> Can you send me privately a tar.bz2 containing your .config,
> .tmp_kallsyms1.S and .tmp_kallsyms2.S so I can try to figure out what's
> going on?

Ok, after some investigation into the files I was able to find out the
problem.

scripts/kallsyms.c uses a subset of the symbol table to optimize the
tokens to use to compress the symbols. It does this because using the
complete set of symbols would be much slower without a significant gain
in compression.

For some reason, in the files sent by Dominik, two aliased symbols
change places from the first to the second step of the kallsyms build
process (__sched_text_start, __down).

Because of this, the subset used for optimization is different and so
are the tokens selected, producing a 2 byte difference in the total size
of the compressed symbol names :P

So I must change the sampling algorithm in a way that is robust to
symbol position changes.

A simple and robust way is to do the sampling on a list of symbols
sorted by symbol name. This way, even if the symbol positions that are
given to scripts/kallsyms change, the symbols sampled will be the same.

I'll do the patch to do this and send it ASAP.

--
Paulo Marques - www.grupopie.com

All that is necessary for the triumph of evil is that good men do nothing.
Edmund Burke (1729 - 1797)
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