title: How should I go about debugging a SIGFPE in a large, unfamiliar software project?
body: <p>I'm trying to get to the bottom of a bug in KDE 5.6. The locker screen breaks no matter how I lock it. Here's the relevant code: <a href="https://github.com/KDE/kscreenlocker/blob/master/abstractlocker.cpp#L51" rel="nofollow">https://github.com/KDE/kscreenlocker/blob/master/abstractlocker.cpp#L51</a></p>
  
  <p>When I run <code>/usr/lib/kscreenlocker_greet --testing</code>, I get an output of:</p>
  
  <pre><code>KCrash: Application 'kscreenlocker_greet' crashing...
  Floating point exception (core dumped)
  </code></pre>
  
  <p>I'm trying to run it with <code>gdb</code> to try and pin the exact location of the bug, but I'm not sure where to set the breakpoints in order to isolate the bug. Should I be looking for calls to <code>KCrash</code>? Or perhaps a <code>raise()</code> call? Can I get <code>gdb</code> to print off the relevant line of code that causes SIGFPE?</p>
  
  <p>Thanks for any advice you can offer.</p>