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This document describes how to install debug packages on Ubuntu, which will aid in providing information for bugs.

Gutsy Gibbon 7.10 , Hardy Heron 8.04 and Intrepid Ibex 8.10

Use this section only if you are using Ubuntu Gutsy 7.10 , Hardy 8.04 or Intrepid Ibex. See the following section if you are using a prior version.

1. Add the following lines to /etc/apt/sources.list: (of course, replace hardy with feisty if you're using 7.04 or gutsy for 7.10)

   deb http://ddebs.ubuntu.com intrepid main restricted universe multiverse
   deb http://ddebs.ubuntu.com intrepid-updates main restricted universe multiverse
   deb http://ddebs.ubuntu.com intrepid-proposed main restricted universe multiverse
   deb http://ddebs.ubuntu.com intrepid-security main restricted universe multiverse

   You may also add these lines using the Synaptic Package Manager:

   • Choose Synaptic via the System > Administration menu.

   • Choose Software Sources via the Settings menu, and click on the Third-Party Software tab.

   • Click the Add button and enter each deb ... line as above one by one and click the Add Source button (you will have to add these lines one at a time).

   • Click the Reload button once you are done adding all the deb lines.

2. Import the debug symbol archive signing key:

   gpg --recv-key 428D7C01
   gpg --check-sigs 428D7C01 # signed by key of Martin Pitt
   gpg -o - --export 428D7C01 | sudo apt-key add -

3. Then run

   sudo apt-get update

   to update your package list.
4. The debug symbol packages have the '-dbgsym' suffix attached, so to install the debug symbols for the package 'yelp', you run:

   dpkg -l yelp

Note the version number installed, e.g. 2.22.1-0ubuntu2.8.04.1, then run:

• sudo apt-get install yelp-dbgsym=2.22.1-0ubuntu2.8.04.1

Alternatively, main Ubuntu repositories could contain '-dbg' debug symbol packages. Those are equivalent to '-dbgsym'. You could use the one you want, but not both.

1. Now you make a Backtrace.

2. You can also run Valgrind, if the program crashes with a "Segmentation fault" or "Bus error".

3. Optionally, you may be asked to produce an Strace.

4. You can also provide this file : ~/.xsession-errors

References

• Announcement: https://lists.ubuntu.com/archives/ubuntu-devel-announce/2006-September/000195.html

Prior Ubuntu versions

Use this section if you are using an Ubuntu version prior to Gusty 7.10.

1. Check if the package has a debugging version available. In general, debugging packages will be named with a -dbg suffix

2. If not, you can generally* build one this way:

Something to keep in mind: if you would like to create a build you're going to need to have the relevant deb-src lines in your /etc/apt/sources.list

1. Install the development scripts:

   sudo apt-get install devscripts fakeroot

2. Find out to which package your program belongs to:

   dpkg --search <program> 

3. Install the build-time dependencies for the package:

   sudo apt-get build-dep <package>

4. Build .debs for debugging:

   export DEB_BUILD_OPTIONS="debug nostrip noopt"
   fakeroot apt-get source -b <package>

5. Install the needed .debs (they will be in the current working directory if the build succeeded):

   sudo debi <package>*.changes

* Most packages support the build of debugging version in this way. If this process doesn't work for a package, please open a bug against it.

The Xorg server

The X server will by default trap its own crashes and dump a stack trace in /var/log/Xorg.0.log. However, this stack trace is modified by the signal handler itself. To get a "normal" crash, which will trigger a core dump (and apport reporting), add this to your /etc/X11/xorg.conf:

Section "ServerFlags"
        Option "NoTrapSignals" "true"
EndSection

Please see DebuggingXorg for how to debug Xorg server crashes.

Info for the BugSquad

If you're trying to apport-retrace a crash report from a bug that didn't happen on the same Ubuntu release as the one you're running, do the following:

Say that you're running Gutsy and the crash happened on feisty:

1. This will create a minimal feisty system.

   sudo mkdir -p /chroots/edgy
   sudo debootstrap edgy /chroots/feisty/

2. Now you change into this minimal fiesty system.

   sudo chroot /chroot/fiesty

3. edit /etc/apt/sources/list and all the repositories you need, especially Martin's ddeb repository.

4. apt-get update; apt-get install gdb apport

5. use apport-retrace as you're used to.

For more information on dealing with bug reports Apport see Bugs/ApportRetraces.

CategoryBugSquad CategoryDebugging