[Python-Dev] Trap SIGSEGV and SIGFPE (original) (raw)

Adam Olsen rhamph at gmail.com
Wed Dec 10 19:59:09 CET 2008

On Wed, Dec 10, 2008 at 11:37 AM, Victor Stinner <victor.stinner at haypocalc.com> wrote:

Oh, I forgot the issue URL: http://bugs.python.org/issue3999

I also attached an example of catching segfaults.

> I published a new version of my fault handler: it installs an handler for > signals SIGFPE and SIGSEGV. Using it, it's possible to catch them and > continue the execution of your Python program. Example:

This will of course leave the program in an undefined state. It is very likely to crash again, emit garbage, hang, or otherwise be useless. Recover after a segfault is dangerous, but my first goal was to get the Python backtrace instead just one line: "Segmentation fault". It helps a lot for debug!

It's possible to print the Python stack purely from C, without invoking any Python code. Even better, you could print the C stack while you're at it! Doing that in a signal handler, and then killing the process, could be seriously considered.

Take a look at http://www.linuxjournal.com/article/6391 . You'll probably need #ifdef's to only use it on certain supported platforms, and probably disable it by default anyway (configure option? Not sure). Still, it'd be useful to have it there.

-- Adam Olsen, aka Rhamphoryncus

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