Re: [PATCH] Fix build error in binutils 2.36

[Michael Chang]

On Thu, Sep 16, 2021 at 11:47:57PM +0200, Daniel Kiper wrote:
> On Mon, Aug 09, 2021 at 12:37:59PM +0800, Michael Chang via Grub-devel wrote:
> > On Thu, Aug 05, 2021 at 03:07:21PM +0200, Daniel Kiper wrote:
> > > On Mon, Aug 02, 2021 at 05:41:15PM +0800, Michael Chang via Grub-devel 
> > > wrote:
> > > > The xen build fails on binutils 2.36 with the following error.
> > > >
> > > > /usr/lib64/gcc/x86_64-suse-linux/10/../../../../x86_64-suse-linux/bin/ld:
> > > > section .note.gnu.property VMA [0000000000400158,0000000000400187]
> > > > overlaps section .bss VMA [000000000000f000,000000000041e1af]
> > >
> > > Could you send us full command which is failing?
> >
> > It is reproducible on xen platfrom with all defaults.
> >
> >  git clone https://git.savannah.gnu.org/git/grub.git
> >  cd grub
> >  ./bootstrap
> >  mkdir build-xen
> >  cd build-xen
> >  ../configure --with-platform=xen
> >  make
> >
> > > Anyway, I would consider writing our own linker script which is dropping
> > > .note.gnu.property if we do not need it.
> >
> > Dropping it from the assembler output is a cleaner cleanup than linker
> > script IMHO. We also faced similar issue in the past to stripping off
> > this section from soruces of objcopy to produce correct binary.
> >
> >  6643507ce build: Fix GRUB i386-pc build with Ubuntu gcc
> >
> > To avoid falling into such trap again when manipulating on object files
> > we'd better use assmbler option as the fix once and for all.
> 
> May I ask you to expand commit message with the information above?

Sure. No problem.

> 
> > > > The most significant factor is that new assembler (gnu as) generates the
> > >
> > > Could you give us gas version which does that?
> >
> >  # as --version
> >  GNU assembler (GNU Binutils; openSUSE Tumbleweed) 2.36.1.20210326-4
> >  Copyright (C) 2021 Free Software Foundation, Inc.
> >  This program is free software; you may redistribute it under the terms of
> >  the GNU General Public License version 3 or later.
> >  This program has absolutely no warranty.
> >  This assembler was configured for a target of `x86_64-suse-linux'.
> >
> > > > .note.gnu.property section as default. This note section overlaps with
> > > > .bss because it doesn't reposition with -Wl,-Ttext,0 with which the base
> > > > address of .text section is set, rather the address of
> > > > .note.gnu.property is calculated for some reason from 0x400000 where the
> > > > elf executable defaults to start.
> > >
> > > Is not it linker bug?
> >
> > The binutils upstream apparently doesn't seem to consider this as a bug ...
> >
> > https://sourceware.org/bugzilla/show_bug.cgi?id=27377
> 
> Please add this information and the link to the bug to the commit message too.
> Additionally, I think it is worth mentioning Gentoo Linux bug [1] in it.

OK. I'll add the suggested information and refernce to next version.

> 
> I treat this patch more as a workaround than real fix. However, after digging
> deeper into this issue I think we do not have better choice here... :-(

I feel likewise. It is no sliver bullet but can help us back on track
and move on.

Thanks,
Michael

> 
> Daniel
> 
> [1] https://bugs.gentoo.org/787221
> 
> _______________________________________________
> Grub-devel mailing list
> Grub-devel@gnu.org
> https://lists.gnu.org/mailman/listinfo/grub-devel