Re: The trouble with __weak and objtool got worse

[Segher Boessenkool <segher@kernel.crashing.org>]

Hi!

On Fri, Apr 15, 2022 at 01:19:04PM +0200, Peter Zijlstra wrote:
[ huge snip ]

> This seems to happen when objtool cannot find a section symbol, in which
> case it falls back to any other symbol to key off of, however in this
> case that goes terribly wrong!

That is an objtool problem then.  Fix objtool so it looks at symbols
directly?

> The other option seems to be to have objtool add section symbols it
> needs, however due to ELF being a total PITA and requiring all LOCAL
> symbols to be before GLOBAL symbols, this would mean re-ordering the
> whole symbol table (I have the code somewhere :-/).

ELF requires no such thing?  Where do you see this?

This is the order you get as output from GNU LD, is that what you mean?
Expecting a specific order when there is in fact total freedom is not a
PITA, it is just the cost of doing business :-)

> Alternatively:
> 
>   https://sourceware.org/pipermail/binutils/2020-December/114671.html
> 
> seems to suggest: -Wa,--generate-unused-section-symbols=yes, ought to
> work, except I'm getting:

That email is for a proposed patch.  Did anything further ever happen
with it?


Segher