From: Brent Roman <brent@...>
Date: 2007-11-13T16:04:45+09:00
Subject: Help tracking down nasty SegFault bug during GC

Gonzalo,

Thanks for confirming that the pointers I'm seeing
indeed indicate
something is trashing memory.  Now, how "my code" could
be doing this is another story ;-)

The wrapping of termios is here:

http://raa.ruby-lang.org/project/ruby-termios

Yes, I'll give valgrind another try,
although I didn't have much luck with it when
I tried a couple months ago.  At least
I now have an idea what's getting trashed.
But, let's face it:  the C-Ruby interpreter
plays fast and loose with memory regions.

So, I'm first going to try using set_trace_func
to get a history of all activity up to
the gdb breakpoint on the GC of the invalid stack
frame after I've set GC.limit=0 to force
a GC on every object allocation.

I'd love to post a .zip, .tar or whatever.
However, you'd need a our custom robotic
hardware to run it!  I've been unable
to duplicate the failure in simulation
thus far.  That's why it's a "nasty" bug.

If anyone would like, I can post some core files
on our FTP server.

- brent