<update>

Changing your script to

#!/usr/bin/perl

use strict;
use warnings;
use lib "$ENV{PWD}";
use myConfig;

# create the objecto for write the db
our $c_config = myConfig->new();

# add default to the configuration db
$c_config->add_default ( default => 'aa' );
$c_config->_write_configuration();
[download]

produces the following output:

### _write_configuration - store start

### _write_configuration - return

### DESTROY - start

### _write_configuration - store start
Segmentation fault
[download]

The segfault is triggered only if store() is called in the DESTROY during global destruction. It occurs in Storable.xs in do_store()

static int do_store(
        pTHX_
        PerlIO *f,
        SV *sv,
        int optype,
        int network_order,
        SV **res)
{
        dSTCXT;       <--- here
        int status;
        ...
[download]

SV *perinterp_sv = *hv_fetch(PL_modglobal,
    MY_VERSION, sizeof(MY_VERSION)-1, TRUE);
stcxt_t * cxt = ((perinterp_sv && SvIOK(perinterp_sv) && SvIVX(perinte
+rp_sv)
    ? (stcxt_t *)SvPVX(SvRV(INT2PTR(SV*,SvIVX(perinterp_sv)))) : (stcx
+t_t *) 0));
[download]

It doesn't occur with the following script:

#!/usr/bin/perl

use strict;
use warnings;
use lib "$ENV{PWD}";
use myConfig;

# create the objecto for write the db
our $c_config = myConfig->new();

# add default to the configuration db
$c_config->add_default ( default => 'aa' );
undef $c_config;
[download]

Seems like during global destruction some things needed are already gone.

</update>

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