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I am fairly new to Ubuntu and I was wonder what a good way is to debug when something crashes?

For example: I installed 11.04 and the default media player banshee makes my laptop crash after a few minutes of playing music. Since the system completely freezes and there is not error message it's hard to find out what is wrong.

Second problem I have is that sometimes the system crashes to login. I am suspecting it to be a Chromium or Flash but I am not 100% sure.

So anybody got some tips on how to debug stuff like this?

muru
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Pickels
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2 Answers2

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Do not login using the login GUI after such a crash. Switch to a text-based login by pressing Ctrl + Alt + F1. Login with your username and password. Errors during a X session are appended to ~/.xsession-errors, but this file is overwritten every login. Make a backup of this file by executing:

mv ~/.xsession-errors{,.1}

This will rename the .xsession-errors file to .xsession_errors.1. Replace the .1 if you want a different suffix. You can now logout from this shell by executing exit.

Check the system logfiles in /var/log. The most interesting files are:

/var/log/kern.log
/var/log/Xorg.0.log (for the current session)
/var/log/Xorg.0.log.old (for previous session)
/var/log/?dm.log (gdm for gnome, kdm for KDE)
Lekensteyn
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    why not mention /var/crash/? This is where /var/log/apport.log sent me. – David LeBauer Jun 12 '12 at 17:08
  • /var/crash does not really contain human-readable error messages, but a file named like _usr_bin_Xorg.0.crash that can be submitted using Apport. – Lekensteyn Jun 12 '12 at 17:14
  • That is what I meant apport.log told me a specific *.crash file to check; ls -ltrh /var/crash/ confirmed that it was generated during the previous crash; but I was thinking that next time I might start with ls -ltrh /var/crash/. – David LeBauer Jun 12 '12 at 21:27
  • Useless, cause Ctrl + Alt + F1 does nothing (and I didn't change any shortcuts). – goulashsoup Jan 29 '24 at 14:20
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All you have to do is to look at the log directory (/var/log/). You can find any crash or regular logs in there.

Some applications can create crash logs in their own directories. For example, ~/.banshee in your home directory.

Coldfish
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  • Crash is a vague term. What exactly do you do if the system freezes completely and nothing out of the ordinary is in the logs? – mikewhatever Aug 23 '11 at 03:46
  • @mikewhatever Necro but found this looking for same type issues. Is 2018 and I'm on Ubuntu 18 and is stable until I debug my application. The whole system freezes and crashes. – Beeeaaar Aug 31 '18 at 17:27