Re: [tip: objtool/urgent] objtool: Fix seg fault with Clang non-section symbols

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Fri, Feb 12, 2021 at 12:45:47PM -0500, Steven Rostedt wrote:
> On Fri, 12 Feb 2021 11:07:50 -0600
> Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> 
> 
> > > Any ideas are appreciated.  
> > 
> > [ Adding Steve Rostedt ]
> > 
> > This error message comes from recordmcount.  It probably can't handle
> > the missing STT_SECTION symbols which are getting stripped by the new
> > binutils.  (Objtool also had trouble with that.)
> > 
> > No idea why you only see this on 4.4 though.
> > 
> 
> Just taking a quick look, but would something like this work?
> 
> I created this against v4.4.257.
> 
> -- Steve
> 
> diff --git a/scripts/recordmcount.h b/scripts/recordmcount.h
> index 04151ede8043..698404f092d0 100644
> --- a/scripts/recordmcount.h
> +++ b/scripts/recordmcount.h
> @@ -437,6 +437,8 @@ static unsigned find_secsym_ndx(unsigned const txtndx,
>  			if (w2(ehdr->e_machine) == EM_ARM
>  			    && ELF_ST_TYPE(symp->st_info) == STT_FUNC)
>  				continue;
> +			if (ELF_ST_TYPE(symp->st_info) == STT_SECTION)
> +				continue;
>  
>  			*recvalp = _w(symp->st_value);
>  			return symp - sym0;
> 


Thanks for the patch, but no, still fails with:

Cannot find symbol for section 8: .text.unlikely.
kernel/kexec_file.o: failed
make[1]: *** [scripts/Makefile.build:277: kernel/kexec_file.o] Error 1
make[1]: *** Deleting file 'kernel/kexec_file.o'