Re: [PATCH] modpost: Ignore Clang LTO suffixes in symbol matching

Petr and Nathan, thanks for the review and suggestions.

I will send v2 shortly to implement the more targeted approach.

Best regards,

Rong

On Wed, Jun 17, 2026 at 2:04 PM Nathan Chancellor <[email protected]> wrote:
>
> On Wed, Jun 17, 2026 at 12:48:10PM +0200, Petr Pavlu wrote:
> > On 6/16/26 12:43 AM, Rong Xu wrote:
> > > A more direct fix for the warnings in
> > > https://lore.kernel.org/oe-kbuild-all/[email protected]/
> > > looks like the following. But I believe the solution provided in the
> > > patch is more comprehensive.
> > >
> > > -Rong
> > >
> > > ======
> > > diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
> > > index abbcd3fc1394..1f0a379b43c8 100644
> > > --- a/scripts/mod/modpost.c
> > > +++ b/scripts/mod/modpost.c
> > > @@ -967,7 +967,7 @@ static int secref_whitelist(const char *fromsec,
> > > const char *fromsym,
> > >         /* symbols in data sections that may refer to any init/exit sections */
> > >         if (match(fromsec, PATTERNS(DATA_SECTIONS)) &&
> > >             match(tosec, PATTERNS(ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS)) &&
> > > -           match(fromsym, PATTERNS("*_ops", "*_console")))
> > > +           match(fromsym, PATTERNS("*_ops", "*_ops.llvm.*", "*_console")))
> > >                 return 0;
> > >
> > >         /* Check for pattern 3 */
> > >
> >
> > This variant makes more sense to me. The initially proposed patch
> > modifies the match() function, which is a generic function to check
> > whether a string matches any of the input patterns. The modpost utility
> > uses it to match both symbol and section names. Adding symbol-specific
> > knowledge to this function seems odd.
>
> Yeah, I had the feeling that it was a bit of a layering violation as
> well. I think I would prefer this targeted fix for now since I will take
> it as a fix for 7.2 in my planned second Kbuild pull request. We can
> revisit the more comprehensive fix if it is needed in the future (while
> seeing if we can address it outside of match() regardless).
>
> > I noticed that LLVM has recently made improvements to reduce the number
> > of these ThinLTO renames [1], which might be worth checking out.
> >
> > [1] https://github.com/llvm/llvm-project/commit/975dba28633d2f3746a8a370741b17024b0f5f9b
>
> Indeed, we have started using that for regular ThinLTO when it is
> available as of commit dc3b90751d6f ("kbuild: Reduce the number of
> compiler-generated suffixes for clang thin-lto build"). Distributed
> ThinLTO support will follow when LLVM 23.1.0 is released.
>
> --
> Cheers,
> Nathan