Re: [PATCH v2] kernel/module.c: heuristic enhancement when INSTALL_MOD_STRIP= "--strip-unneeded" is used

From: Vimal Agrawal
Date: Fri Dec 24 2021 - 20:08:17 EST


On Fri, Dec 24, 2021 at 12:17 PM Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
>
> I don't think we can support passing arbitrary linker options and
> expects things to work. If we want to support --strip-unneeded
> it needs a good rationale and be added as a direct config option.
INSTALL_MOD_STRIP was provided to give flexibility for providing
strippping options. It will be a separate discussion if we want to
continue allowing this flexibility or not but it is available now. I
see that it works but just that it is behaving erratically during
symbol decodes. I tried few other stripping options. --strip-all does
not work and insmod fails as it needs some symbols which is fine as it
is hinting the user there is a problem with stripping option. This is
not the case with --strip-unneeded option as it builds and loads/works
fine but fails to decode symbols properly sometimes.

One of the rationale for --strip-unneeded option is that it
significantly reduces the size of .ko without affecting its
functionality ( though debuggability takes a hit). I guess many
platforms/products that need limited memory footprint might be using
this option.

I am fine if we decide to say that --strip-unneeded option is not
supported by kbuild/INSTALL_MOD_STRIP which is not the case now. In
that case, I agree that this patch will not even be required.

Vimal