[dancer-users] Get backtrace for stuck Dancer process

[Warren Young]

On Sep 28, 2018, at 1:13 AM, Stefan Hornburg (Racke) <racke at linuxia.de> wrote:
> 
> At any rate, you can strace the Dancer process(es) and see what system calls it does.

I’m quite familiar with strace, but I rejected that out of hand at the time, since most Perl code is running way above the OS’s syscall interface.

There are only a couple of cases I can think of where what it says might help.  E.g. stuck on accept(2).

No, I really do want to be able to produce a Perl-level stack trace, on demand, without killing the program, as via Carp::confess().

It looks like “perl -d” can’t attach to a running program, either, which would let me use some of these fine Perl modules to produce a backtrace.

I found a partial solution, though:

    https://metacpan.org/pod/App%3a%3aStacktrace

Unfortunately for me, it requires Perl 5.10, and this problem happened on a box that’s still running 5.8.  (Don’t ask, can’t avoid that.)