DMD Generated Executable Segfaults on Ubuntu 12.10 64-bit with Hardened GCC

Question

I'm having problems getting DMD 2.061 to work on my configuration of Ubuntu 12.10.

When I first install it using the following script

if grep -qE "^deb http://d-apt.googlecode.com/files /" /etc/apt/sources.list; then
    echo "Already there";
else
    echo 'deb http://d-apt.googlecode.com/files /' | sudo tee -a /etc/apt/sources.list;
fi

sudo apt-get update -q=2;
sudo apt-get --yes --allow-unauthenticated install d-apt-keyring;
sudo apt-get update -q=2;

sudo apt-get install -y dmd;
sudo apt-get install -y libgtkd-dev libgtkd-doc;
sudo apt-get install -y libtango-dev libtango-doc;
sudo apt-get install -y libdcollections-dev libdcollections-doc;
sudo apt-get install -y liborange-dmd-dev liborange-dmd-doc;
sudo apt-get install -y libderelict-dev;
sudo apt-get install -y libgl3n-dev libgl3n-doc;
sudo apt-get install -y libdsqlite-dev libdsqlite-doc;
sudo apt-get install -y libspiritd-dev libspiritd-doc;
sudo apt-get install -y libdstats-dev libdstats-doc;
sudo apt-get install -y libmsgpack-dmd-dev libmsgpack-dmd-doc;
sudo apt-get install -y vibe vibe-doc;

Everything works fine.

But...

then suddently after I've installed my favorite software from some Ubuntu PPA's the code dmd generates segfaults. As I use a lot of extra PPAs it is not easy to find out which PPA causes the crash. I have tried this on a default (unmodified) user.

Specifically the commmand

strace -f dmd -run f.d

where f.d contains

import std.stdio;
void main(string args[])
{
  auto x = 0b10;
  writeln(x);
}

crashes as

getrlimit(RLIMIT_STACK, {rlim_cur=8192*1024, rlim_max=RLIM_INFINITY}) = 0
brk(0)                                  = 0x1908000
brk(0x1929000)                          = 0x1929000
--- SIGSEGV (Segmentation fault) @ 0 (0) ---
+++ killed by SIGSEGV (core dumped) +++

The next I tried was to compare the sha1sum's of all the dynamic libraries used by dmd and in turn my program:

linux-vdso.so.1 =>  (0x00007ffff53ff000)
libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f87f0ba0000)
libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f87f0983000)
libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f87f0686000)
libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f87f0470000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f87f00b1000)
/lib64/ld-linux-x86-64.so.2 (0x00007f87f0ecf000)

to the ones installed by default on my TV-system which have no extra PPAs.

It turned out that /usr/lib/x86_64-linux-gnu/libstdc++.so.6 and /lib/x86_64-linux-gnu/libgcc_s.so.1 differed.

So then I copied over these files to my original system and directed to them using

LD_PRELOAD=libstdc++.so.6:libgcc_s.so.1

But...I still get the same segfault...and there I'm lost. What on earth could cause this problem otherwise? Should I start to compare the files (collected by strace) that are read by dmd and my program?

My system works find elsewhere along with gcc, g++. So I'm posting this in the hope that my configuration may have spotted a vulnerability in the code generated from DMD.

Finally I print some defaults about the compiler version on my failing system

dummy@lappis:~$ gcc --version
gcc-4.7.real (Ubuntu/Linaro 4.7.2-5ubuntu1) 4.7.2

dummy@lappis:~$ dpkg -S /usr/bin/gcc-4.7
diversion by hardening-wrapper from: /usr/bin/gcc-4.7
diversion by hardening-wrapper to: /usr/bin/gcc-4.7.real
gcc-4.7, hardening-wrapper: /usr/bin/gcc-4.7

and on my working (Ubuntu 12.10 without extra PPAs)

per@buddha:~$ gcc --version
gcc (Ubuntu/Linaro 4.7.2-2ubuntu1) 4.7.2
    Copyright © 2012 Free Software Foundation, Inc.

According to gdb rdmd run with f.d it crashes in gc_init():

Program received signal SIGSEGV, Segmentation fault.
0x0000000000417fec in gc_init ()
(gdb) where
#0  0x0000000000417fec in gc_init ()
#1  0x0000000000416a22 in rt.dmain2._d_run_main() ()
#2  0x0000000000416546 in rt.dmain2._d_run_main() ()
#3  0x00000000004164fd in _d_run_main ()
#4  0x000000000041633b in main ()`

I've finally tried building dmd from source but with the same segfaulting result.

Answer 1

It sounds like the problem I had earlier using Hardened GCC on Gentoo.

Here is the bug tracker: http://d.puremagic.com/issues/show_bug.cgi?id=5278

You can work around it by recompiling DMD with this patch and then adding "-cflag=-fno-pie" to the DFLAGS in your /linux/bin64/dmd.conf file (or wherever it is relative to your newly compiled dmd binary).

Alternatively, find a way to use non-hardened GCC for your D compiling. You might be able to build your own copy of GCC separate from Ubuntu's packaging and then convince DMD to use your copy instead of Ubuntu's. My apologies for forgetting the details, it's been a while since I've fought with this one.