[tor-dev] Tor crash debug

[Roger Dingledine]

On Fri, Apr 29, 2016 at 02:24:20PM +1000, Tim Wilson-Brown - teor wrote:
> > Program received signal SIGSEGV, Segmentation fault.
> > 0x00005555555c02d6 in rend_client_get_random_intro_impl (
> >    entry=0x5555555bf1bf <rend_client_fetch_v2_desc+114>, strict=0, warnings=0)
> >    at src/or/rendclient.c:1353
> > 1353      smartlist_add_all(usable_nodes, entry->parsed->intro_nodes);
> > 
> > Any ideas what is the problem? Is there anything more I could do to debug this?
> 
> Looks like either "entry" or "parsed" is NULL.
> 
> You could tell us what version of tor you're running (it's not master, the line numbers are wrong), and give us the last few log messages before the crash.

Yep! Also, the output of 'bt all' could be useful.

See https://www.torproject.org/docs/faq#TorCrash for more things
to think about -- the debug-level log right before it happens will
be useful, and also knowing when during operation it happens (soon
after? reliably? etc), and also your torrc.

But most importantly, you should open a ticket on trac and start
accumulating details there. That way the history will be on the
trac ticket, and people can follow it there rather than here.

Thanks,
--Roger