Re: [PATCH v9 02/15] livepatch: use `-z unique-symbol` if available to nuke pos-based search

Miroslav Benes
2022-01-03T13:55:48Z

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On Thu, 30 Dec 2021, Fāng-ruì Sòng wrote:

> On Thu, Dec 30, 2021 at 3:11 AM Borislav Petkov <bp@alien8.de> wrote:
> >
> > On Thu, Dec 23, 2021 at 01:21:56AM +0100, Alexander Lobakin wrote:
> > > [PATCH v9 02/15] livepatch: use `-z unique-symbol` if available to nuke pos-based search

...

> Apologies since I haven't read the patch series.
>
> The option does not exist in ld.lld and I am a bit concerning about
> its semantics: https://maskray.me/blog/2020-11-15-explain-gnu-linker-options#z-unique-symbol
>
> I thought that someone forwarded my comments (originally posted months
> on a feature request ago) here but seems not.
> (I am a ld.lld maintainer.)

Do you mean
https://lore.kernel.org/all/20210123225928.z5hkmaw6qjs2gu5g@google.com/T/#u
?

Unfortunately, it did not lead anywhere. I think that '-z unique-symbol'
option should work fine as long as the live patching is concerned. Maybe I
misunderstood but your concerns mentioned at the blog do not apply. The
stability is not an issue for us since we (KLP) always work with already
built and fixed kernel. And(at least) GCC already uses number suffices for
IPA clones and it has not been a problem anywhere.

Am I wrong?

Thanks

Miroslav