“skid mark”

December 18, 2009 in Firefox, Programming | 6 comments

A new phrase that I learned yesterday. Probably something that’s been around computers for a long time, but it was my first exposure to it.

Basically a “skid mark” is something you leave in code as a signature so that in a crash dump you can figure out how you got there.

We’ve been doing a huge amount of work in Firefox 3.5 and 3.6 to reduce the number of crashes. For some crashes we have stack traces, but not a lot of data on how we got to that stack. So we’re actually checking in code changes and and shipping them into the wild to see how they change crash signatures.

The interesting thing is that it’s working – we’ve been able to track down some pretty serious crashes with this technique.

  1. Matthew Barnes’s avatar

    Matthew Barnes on December 18, 2009 at 5:26 pm

    I’ve always called them “breadcrumbs” but I think I like “skid marks” better.

    This sounds more sophisticated than the usual “dump warnings to the terminal when things start to go downhill” approach. Can you elaborate on the technique?

  2. tm’s avatar

    tm on December 18, 2009 at 5:55 pm

    i thought skid mark has been used for something totally else:
    http://www.urbandictionary.com/define.php?term=skid+mark

  3. Grumpy Marmoset’s avatar

    Grumpy Marmoset on December 18, 2009 at 6:27 pm

    Is there any chance you will fix the nasty database bug that causes a traceless crash every single time you open the History sidebar? Surely you can search and display an sql table while it is updated? No? Disable the updates until the sidebar closes?

  4. Christopher Blizzard’s avatar

    Christopher Blizzard on December 18, 2009 at 7:31 pm

    Grumpy!

    Do you know if there’s a bug open on that?

  5. Grumpy Marmoset’s avatar

    Grumpy Marmoset on December 21, 2009 at 10:12 am

    I assume so as many others reported the same – “clean” crash with no error message, no coredump, but tabs restored on restarting. It is described by several here http://ubuntuforums.org/showthread.php?t=1257910

    The solution given is to not use the history sidebar. The fault is replicated soon after opening the history sidebar.

  6. David Schleef’s avatar

    David Schleef on December 30, 2009 at 11:24 pm

    My favorite skid mark usually involves some permutation of 0xdeadbeef.