Debian Bug report logs - #852035
binutils: bfd stumbles over duplicated symbols generated by gold

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Message #5 received at submit@bugs.debian.org (full text, mbox, reply):

From: Aurelien Jarno <aurel32@debian.org>

To: Debian Bug Tracking System <submit@bugs.debian.org>

Subject: binutils: bfd stumbles over duplicated symbols generated by gold

Date: Fri, 20 Jan 2017 22:55:42 +0100

Package: binutils
Version: 2.27.51.20161231-1
Severity: serious

When the gold linker is used, it sometimes generates duplicated symbols.
It's not something new, and can be seen for example in
qtbase-opensource-src 5.7.1+dfsg-2:

  1081: 00000000004caf88     0 NOTYPE  GLOBAL DEFAULT ABS __bss_start@Qt_5
  1082: 00000000004caf88     0 NOTYPE  GLOBAL DEFAULT ABS __bss_start@Qt_5

Note that bfd doesn't generate duplicated with the same command line
beside the -fuse-ld=gold. This used to not be a problem with both gold
and bfd. However the upstream commit eb3908448b , which first appeared
in binutils 2.27.51.20161231-1, causes this symbols to become
relocatable. This can be seen in qtbase-opensource-src 5.7.1+dfsg-3:

  1081: 00000000004caf88     0 NOTYPE  GLOBAL DEFAULT 19 __bss_start@Qt_5
  1082: 00000000004caf88     0 NOTYPE  GLOBAL DEFAULT 19 __bss_start@Qt_5

This in turn causes bfd to fail to link binaries against libQt5Core.so
or libQt5Gui.so, for example when building libqapt (see [1] for a full
build log):

  /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5.7.1:(*IND*+0x0): multiple definition of `__bss_start'
  /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5.7.1:(*IND*+0x0): multiple definition of `_edata'
  /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5.7.1:(*IND*+0x0): multiple definition of `_end'
  /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.7.1:(*IND*+0x0): multiple definition of `__bss_start'
  /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.7.1:(*IND*+0x0): multiple definition of `__bss_start'
  /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.7.1:(*IND*+0x0): multiple definition of `_edata'
  /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.7.1:(*IND*+0x0): multiple definition of `_edata'
  /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.7.1:(*IND*+0x0): multiple definition of `_end'
  /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.7.1:(*IND*+0x0): multiple definition of `_end'

Note however that having duplicated symbols doesn't cause a problem to
gold, only to bfd.

I don't really know how this should be fixed, either bfd should accept
duplicated symbols, or gold should stop generating them.


[1] https://buildd.debian.org/status/fetch.php?pkg=libqapt&arch=mipsel&ver=3.0.2-1%2Bb2&stamp=1484821949&raw=0

-- System Information:
Debian Release: 9.0
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.9.0-trunk-amd64 (SMP w/4 CPU cores)
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Message #28 received at 852035@bugs.debian.org (full text, mbox, reply):

From: Emilio Pozuelo Monfort <pochu@debian.org>

To: 852035@bugs.debian.org

Subject: Re: binutils: bfd stumbles over duplicated symbols generated by gold

Date: Sun, 29 Jan 2017 18:38:34 +0100

Control: severity -1 important

On Fri, 20 Jan 2017 22:55:42 +0100 Aurelien Jarno <aurel32@debian.org> wrote:
> Package: binutils
> Version: 2.27.51.20161231-1
> Severity: serious
> 
> When the gold linker is used, it sometimes generates duplicated symbols.
> It's not something new, and can be seen for example in
> qtbase-opensource-src 5.7.1+dfsg-2:
> 
>   1081: 00000000004caf88     0 NOTYPE  GLOBAL DEFAULT ABS __bss_start@Qt_5
>   1082: 00000000004caf88     0 NOTYPE  GLOBAL DEFAULT ABS __bss_start@Qt_5
> 
> Note that bfd doesn't generate duplicated with the same command line
> beside the -fuse-ld=gold. This used to not be a problem with both gold
> and bfd. However the upstream commit eb3908448b , which first appeared
> in binutils 2.27.51.20161231-1, causes this symbols to become
> relocatable. This can be seen in qtbase-opensource-src 5.7.1+dfsg-3:
> 
>   1081: 00000000004caf88     0 NOTYPE  GLOBAL DEFAULT 19 __bss_start@Qt_5
>   1082: 00000000004caf88     0 NOTYPE  GLOBAL DEFAULT 19 __bss_start@Qt_5
> 
> This in turn causes bfd to fail to link binaries against libQt5Core.so
> or libQt5Gui.so, for example when building libqapt (see [1] for a full
> build log):
> 
>   /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5.7.1:(*IND*+0x0): multiple definition of `__bss_start'
>   /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5.7.1:(*IND*+0x0): multiple definition of `_edata'
>   /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5.7.1:(*IND*+0x0): multiple definition of `_end'
>   /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.7.1:(*IND*+0x0): multiple definition of `__bss_start'
>   /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.7.1:(*IND*+0x0): multiple definition of `__bss_start'
>   /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.7.1:(*IND*+0x0): multiple definition of `_edata'
>   /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.7.1:(*IND*+0x0): multiple definition of `_edata'
>   /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.7.1:(*IND*+0x0): multiple definition of `_end'
>   /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.7.1:(*IND*+0x0): multiple definition of `_end'
> 
> Note however that having duplicated symbols doesn't cause a problem to
> gold, only to bfd.
> 
> I don't really know how this should be fixed, either bfd should accept
> duplicated symbols, or gold should stop generating them.

This is work-arounded in binutils/2.27.90.20170124-2. Let's keep this open until
we have a proper fix and not a workaround, but no longer at RC severity.

Cheers,
Emilio

Message #37 received at 852035@bugs.debian.org (full text, mbox, reply):

From: Dmitry Shachnev <mitya57@debian.org>

To: Emilio Pozuelo Monfort <pochu@debian.org>, 852035@bugs.debian.org

Cc: Lisandro Damián Nicanor Pérez Meyer <lisandro@debian.org>

Subject: Re: Bug#852035: binutils: bfd stumbles over duplicated symbols generated by gold

Date: Fri, 18 Aug 2017 14:04:26 +0300

[Message part 1 (text/plain, inline)]

Control: severity -1 serious

On Sun, Jan 29, 2017 at 06:38:34PM +0100, Emilio Pozuelo Monfort wrote:
> Control: severity -1 important
>
> This is work-arounded in binutils/2.27.90.20170124-2. Let's keep this open until
> we have a proper fix and not a workaround, but no longer at RC severity.

The workaround was dropped in binutils/2.28.51.20170620-1 (which reached
unstable on July 25th), so we have this bug again with Qt 5.9, and it is
blocking its transition. Bumping the severity back.

A couple of examples, thanks to Adrian Bunk:

https://tests.reproducible-builds.org/debian/rbuild/unstable/amd64/kphotoalbum_5.2-2.rbuild.log
https://tests.reproducible-builds.org/debian/rbuild/unstable/amd64/italc_3.0.3+dfsg1-1.rbuild.log

It also makes qtwebkit FTBFS on armel and armhf.

Either the workaround needs to be reintroduced, or we will have to rebuild
Qt with bfd instead of gold.

--
Dmitry Shachnev

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