Re: [Heroes] Bug#169525: heroes-common: Fatal signal: Segmentation Fault (SDL Parachute Deployed)

[Jean Delvare]

> > Guess what? I tried four times, and never got it to crash :-(
> 
> Great, a Heisenbug. Just what we needed most. OK, another try: Start
> heroes as usual and attach the debugger afterwards. Type 'ps -x | grep
> heroes' to find out the PID (pick the lowest one, maybe you can also
> try the others) and run 'gdb heroes PID'. Hopefully this works, I'm
> running out of ideas.

I have been able to reproduce the bug. Heroes 0.21 configured with
--enable-debug (and no sound, I don't have any suitable lib on my
system). The host is an Intel Pentium II 233 running Slackware 8.1
(gcc-2.95.3, glibc-2.2.5) with SDL 1.2.4.

The first time I had no backtrace, only "Cannot access memory at 0x11"
or similar (cannot remember the exact value). The second time, more
luck:

#0  0x0804dad3 in initialize_deck_font () at fontdata.c:91
91            for (height = 0; height < deck_font->height; ++height) {
(gdb) bt
#0  0x0804dad3 in initialize_deck_font () at fontdata.c:91
#1  0x0806a6ce in draw_level (p=-1073743384) at render.c:548
Cannot access memory at address 0x17
(gdb)

FWIW, the first time I was physically on the machine and the crash
occured after a few seconds (less that one minute). The second time I
was running through ssh from another machine (really slow) and the crash
occured after much more time (say 5 minutes). This makes me think it
could be a race condition. Also, I suspect the yellow spinning arrow
(previously "Get this bonus" or something) around the Length+ bonus to
be the cause (or part of it, at least). It would make sense because it
is used only for the first level of the Quest mode, and Christoph Claus
reported the crash happens only in Quest mode and only at level 1.

Christoph, can your host be considered as slow?

I don't plan to look at the code, Alexandre and Ingo know it much better
than I do and I hope they'll find it. Of course, I can do any kind of
tests if it can help.

-- 
Jean Delvare
http://www.ensicaen.ismra.fr/~delvare/