Segfault when using Data::Dumper

[bfg]

The following code causes process segfault:

#!/usr/bin/perl

use strict;
use warnings;
use Data::Dumper;

sub { return [ 200, [ 'Content-Type', 'text/plain' ], [ "Hello world!\n" . Dumper($_[0]) ]] }

Opensuse 11.4 32bit, linux 2.6.37, ev 4.03, perl 5.12.3 (threads enabled).

Tested with curl:

• first request: empty response
• second requrest: empty response
• third request: correct output
• 4th request: segfault

Process output:

$ feersum --listen :9002 app.pl 
Feersum try_conn_write: Bad file descriptor
close at write shutdown: Bad file descriptor
^C
$ feersum --listen :9002 app.pl 
Segmentation fault

GDB stack trace:

(gdb) bt
#0  0xb7456718 in psgix_io_svt_get (my_perl=0x830d008, sv=0x85d08c4, mg=0x85d9354) at Feersum.xs:2103
#1  0x08106071 in Perl_mg_get ()
#2  0xb7426834 in DD_dump (my_perl=0x830d008, val=0x85d08c4, name=0x85dc0cc "$VAR1->{'psgix.io'}", namelen=19, retval=0x858b184, seenhv=0x858b704, postav=0x85d0a64, levelp=0xbf809128, indent=2, pad=0x858b574, xpad=0x858b014, 
    apad=0x858b664, sep=0x858b094, pair=0x85d0bd4, freezer=0x858b414, toaster=0x858b424, purity=0, deepcopy=0, quotekeys=1, bless=0x858b5f4, maxdepth=0, sortkeys=0x0) at Dumper.xs:307
#3  0xb7429aaf in DD_dump (my_perl=0x830d008, val=0x858b664, name=0x85d9544 "$VAR1", namelen=5, retval=0x858b184, seenhv=0x858b704, postav=0x85d0a64, levelp=0xbf809128, indent=2, pad=0x858b574, xpad=0x858b014, apad=0x858aef4, 
    sep=0x858b094, pair=0x85d0bd4, freezer=0x858b414, toaster=0x858b424, purity=0, deepcopy=0, quotekeys=1, bless=0x858b5f4, maxdepth=0, sortkeys=0x0) at Dumper.xs:789
#4  0xb742ecdc in XS_Data__Dumper_Dumpxs (my_perl=0x830d008, cv=0x85895c4) at Dumper.xs:1196
#5  0x08133820 in Perl_pp_entersub ()
#6  0x080f9172 in Perl_runops_debug ()
#7  0x08083bb8 in Perl_call_sv ()
#8  0xb7463b63 in call_request_callback () at Feersum.xs:1931
#9  process_request_ready_rinq () at Feersum.xs:732
#10 0xb7486f93 in ev_invoke_pending (loop=0xb74eb820) at libev/ev.c:2117
#11 0xb74c5f39 in ev_run (loop=0xb74eb820, flags=0) at libev/ev.c:2483
#12 0xb74c727f in XS_EV_run (my_perl=0x830d008, cv=0x835c1d4) at EV.c:827
#13 0x08133820 in Perl_pp_entersub ()
#14 0x080f9172 in Perl_runops_debug ()
#15 0x0808c05c in perl_run ()
#16 0x0806493d in main ()
(gdb) 

[audreyt]

Confirmed; this is because $env->{'psgix.io'} did not survive a mg_get(). It's a legitimate issue.

FWIW, Data::Dumper would work correctly if $env->{'psgix.io'} was first deleted -- I had to work around that for Mojo in https://github.com/kraih/mojo/pull/152 .

[bluet]

I think this issue could be closed. (if stash's still here....)

[audreyt]

Hi BlueT, do you mean that it's been fixed by an upstream module e.g. Plack?