On Thu, Feb 03, 2005 at 05:01:26PM -0800, Ofer Nave wrote:
> I've spent all day trying to figure out why my program segfaults when I
> hit Ctrl-C. It's a massive program, with thousands of lines and dozens
> of modules and PoCo::Child and PoCo::IKC, and it spawns processes on
> remote hosts and communicates with them... total mess.
Aie!! Thanks for shrinking the test case. I don't have Sybase to run
it against, but it's a lot easier to inspect by eye this way.
> After many hours, I finally got it down to a simple eight line program
> that demonstrates the problem:
>
> #!/usr/bin/perl -w
> use DBD::Sybase;
> use POE;
> print "started (PID=$$)\n";
> print "going into infinite loop\n";
> my $i = 0;
> while ( 1 ) { $i += 2; $i -= 2; last if ( $i == 9999 ); }
> print "done\n";
>
> If I run this program and then hit Ctrl-C, it says 'Segmentation fault'
> and returns to the prompt. It also leaves behind a fork of the process
> with a pid equal to the original pid + 2. That is, if I started the
> program and it had pid 13582 when it started, then after it segfaults,
> there's an identical process hanging around the process table with pid
> 13584.
POE doesn't fork, so I can only blame DBD::Sybase for that.
> If I comment out 'use POE', it doesn't segfault. If I comment out
> 'DBD::Sybase', it ignores my Ctrl-C and I have to use the kill command.
POE before 0.30 registers signal handlers for most of %SIG because it
supports a generic _signal event. POE 0.30 and beyond don't register
signal handlers willy-nilly, so at the very least ^C should interrupt
your test program.
> I'm not exactly sure how to go about solving this problem. I also don't
> know much about what POE is doing with signals in the background, but
> from a few tests it's obvious that %SIG is almost empty in a typical
> non-POE perl script, but the minute you include POE, all signals get
> handlers. That might explain why I can't Ctrl-C when I include POE, but
> it doesn't explain why I Ctrl-C segfaults when I include both POE and
> DBD::Sybase.
I don't want to sound cold-hearted, but you should probably try the
test case against the latest CPAN release of POE. The newer signal
semantics may solve your problem.
I'm sure hoping they do, anyway. :)
--
Rocco Caputo - http://poe.perl.org/
