Skip to content

Debugging Segfaults

If you experience a crash/segfault or hang (especially in MC) you can run gdb on python to find the crash or hang. You can attach a debugger to the running mc process like this:

$ ps aux | grep mpf
jan       9678 12.4  0.3 1082068 127304 pts/2  SNl+ 23:17   0:06 /usr/bin/python3 /usr/local/bin/mpf mc
jan       9760 37.0  0.1 571368 56660 pts/3    Sl+  23:17   0:01 /usr/bin/python3 /usr/local/bin/mpf game -X

In this example 9678 is the pid of MC and 9760 is the pid of MPF. You can then attach gdb:

$ sudo gdb python3 9678
[...]
(gdb) thread apply all bt
[...]
(gdb) thread apply all py-bt
[...]

Please send us the complete output of gdb. That will help us to figure out the problem.

Something missing or wrong? You can fix it!

This website is edited by people like you! Is something wrong or missing? Is something out of date, or can you explain it better?

Please help us! You can fix it yourself and be an official "open source" contributor!

It's easy! See our Beginner's guide to editing the docs.

Page navigation via the keyboard: < >

You can navigate this site via the keyboard. There are two modes:

General navigation, when search is not focused:

  • F , S , / : open search dialog
  • P , , : go to previous page
  • N , . : go to next page

While using the search function:

  • Down , Up : select next / previous result
  • Esc , Tab : close search
  • Enter : go to highlighted page in the results