gdb hang with maverick on Amazon ami-c81f4f8d

[Ram Rao]

Binary package hint: gdb

Hi,
  When trying to run gdb (7.2-1ubuntu2) on Amazon EC2 with a Maverick AMI (Ubuntu 10.10), I am getting a hard hang of the system. Ctrl-c doesn't help. Rebooting the instance doesn't help. The only thing that seems to work is to terminate the instance and restart a new one.
  The attached script is the list of commands that I use on a new EC2 instance. GDB will run and place me at the gdb prompt. If I type 'run', then the instance hangs. Below is a dump of the terminal output.

Ram

ubuntu@ip-10-166-38-236:~/cutycapt/CutyCapt$ DISPLAY=:1 gdb --args
CutyCapt --url=http://www.google.com --out=temp.png
GNU gdb (GDB) 7.2-ubuntu
Copyright (C) 2010 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/
gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show
copying"
and "show warranty" for details.
This GDB was configured as "i686-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /home/ubuntu/cutycapt/CutyCapt/CutyCapt...(no
debugging symbols found)...done.
(gdb) run
Starting program: /home/ubuntu/cutycapt/CutyCapt/CutyCapt --url=http://
www.google.com --out=temp.png
[Thread debugging using libthread_db enabled]
[New Thread 0xb50e7b70 (LWP 13984)]
[New Thread 0xb46f5b70 (LWP 13985)]

ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: gdb 7.2-1ubuntu2
ProcVersionSignature: User Name 2.6.35-22.33-virtual 2.6.35.4
Uname: Linux 2.6.35-22-virtual i686
Architecture: i386
Date: Thu Nov 11 19:37:59 2010
Ec2AMI: ami-c81f4f8d
Ec2AMIManifest: (unknown)
Ec2AvailabilityZone: us-west-1a
Ec2InstanceType: c1.medium
Ec2Kernel: aki-99a0f1dc
Ec2Ramdisk: unavailable
ProcEnviron:
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: gdb

[Scott Moser (smoser)]

This is reproducible I did so by launching an instance of ami-74c0371d
us-east-1 ami-74c0371d canonical ubuntu-maverick-daily-i386-desktop-20101110

I used desktop only because its faster to get X dependencies.

in instance, connected with ssh -X:

  % sudo apt-get install subversion libqt4-webkit libqt4-dev g++
  % svn co https://cutycapt.svn.sourceforge.net/svnroot/cutycapt
  % cd cutycapt/CutyCapt
  % qmake
  % make
  % echo $DISPLAY
  localhost:10.0
  % xterm
  # just verified that this actually came up
  % ./CutyCapt --url=http://www.example.org --out=example.png
  % ./CutyCapt --url=http://www.example.org --out=example.png;
  % echo $?; ls -l example.png
  0
  -rw-r--r-- 1 ubuntu ubuntu 18378 2010-11-15 21:03 example.png

Then, try from within gdb:
  % gdb --args ./CutyCapt --url=http://www.example.org --out=example.png

Doing the above results in a lockup. I rebooted the instance via ec2 api call, then got console output, and am attaching that here.

Note, I do not believe that this is a result of slow X11 link as was my first suspicion. That is because I tried:
 % xvfb-run bash
 % gdb --args ./CutyCapt --url=http://www.example.org --out=example.png

 which resulted in the same hang. That *should* have used xvfb's fake X11 server (DISPLAY=:99), rather htan the tunnelled X11 connection.

[Matthias Klose (doko)]

closing this issue; please recheck with gdb in 14.04 LTS and 14.10. Feel free to re-open the issue if the problem persists.