[Python-Dev] Trap SIGSEGV and SIGFPE

[Adam Olsen]

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