changing STDOUT encoding and fork CRASH

[wolf391]

could someone shed some light why this program CRASHES the perl interpreter (win7, perl 5.12.4 32bit)

#!/usr/bin/perl
use strict;
use warnings;
use feature qw(say switch);
use utf8;

binmode( STDOUT, ':encoding(cp1252)');

my $pid = fork; die "Failed to fork: $! \n" unless defined $pid;

if ($pid) {
    say 'äbökü€';
    wait;
    exit 0;
}

say 'äbökü€';
exit 0;

while THIS works just fine:

#!/usr/bin/perl
use strict;
use warnings;
use feature qw(say switch);
use utf8;

my $pid = fork; die "Failed to fork: $! \n" unless defined $pid;

if ($pid) {
    binmode( STDOUT, ':encoding(cp1252)');
    say 'äbökü€';
    wait;
    exit 0;
}

binmode( STDOUT, ':encoding(cp1252)');
say 'äbökü€';
exit 0;

really can't wrap my head around why the first example crashes.

[bulk88]

crash is

>    encoding.dll!PerlIOEncode_getarg(interpreter * my_perl=0x00b430b4
+, _PerlIO * * f=0x00b4382c, clone_params * param=0x0012fa98, int flag
+s=1)  Line 62 + 0x6    C
     perl517.dll!PerlIOBase_dup(interpreter * my_perl=0x00b430b4, _Per
+lIO * * f=0x00000000, _PerlIO * * o=0x008f43f4, clone_params * param=
+0x0012fa98, int flags=1)  Line 2303 + 0xc    C
     encoding.dll!PerlIOEncode_dup(interpreter * my_perl=0x00b430b4, _
+PerlIO * * f=0x009ee714, _PerlIO * * o=0x008f43f4, clone_params * par
+ams=0x0012fa98, int flags=1)  Line 566 + 0x16    C
     perl517.dll!PerlIO_fdupopen(interpreter * my_perl=0x0012f9cc, _Pe
+rlIO * * f=0x00070023, clone_params * param=0x0012fa98, int flags=1) 
+ Line 579 + 0x13    C
     perl517.dll!Perl_fp_dup(interpreter * my_perl=0x00b430b4, _PerlIO
+ * * const fp=0x008f43f4, const char type=0, clone_params * const par
+am=0x0012fa98)  Line 11492 + 0xb    C
     perl517.dll!PerlIO_clone(interpreter * my_perl=0x003c5010, interp
+reter * proto=0x00b4382c, clone_params * param=0x0012fa98)  Line 693 
++ 0xc    C
     perl517.dll!perl_clone_using(interpreter * proto_perl=0x00345ebc,
+ unsigned long flags=1, IPerlMem * ipM=0x00000001, IPerlMem * ipMS=0x
+009048d8, IPerlMem * ipMP=0x009048f4, IPerlEnv * ipE=0x00904910, IPer
+lStdIO * ipStd=0x00904948, IPerlLIO * ipLIO=0x009049e4, IPerlDir * ip
+D=0x00904a4c, IPerlSock * ipS=0x00904a78, IPerlProc * ipP=0x00904b28)
+  Line 13350    C
     perl517.dll!PerlProcFork(IPerlProc * piPerl=0x003444a8)  Line 183
+2 + 0x3e    C
     perl517.dll!Perl_pp_fork(interpreter * my_perl=0x00345ebc)  Line 
+4051 + 0xa    C
     perl517.dll!Perl_runops_standard(interpreter * my_perl=0x00345ebc
+)  Line 42 + 0x4    C
     perl517.dll!S_run_body(interpreter * my_perl=0x003c5010, long old
+scope=1)  Line 2430 + 0xa    C
     perl517.dll!perl_run(interpreter * my_perl=0x00345ebc)  Line 2346
+ + 0x8    C
     perl517.dll!RunPerl(int argc=2, char * * argv=0x01342478, char * 
+* env=0x00342da8)  Line 270 + 0x6    C
     perl.exe!mainCRTStartup()  Line 398 + 0xe    C
     kernel32.dll!_BaseProcessStart@4()  + 0x23

SV *
PerlIOEncode_getarg(pTHX_ PerlIO * f, CLONE_PARAMS * param, int flags)
{
    PerlIOEncode *e = PerlIOSelf(f, PerlIOEncode);
    SV *sv = &PL_sv_undef;
    PERL_UNUSED_ARG(param);
    PERL_UNUSED_ARG(flags);
    if (e->enc) {
    dSP;
    /* Not 100% sure stack swap is right thing to do during dup ... */
    PUSHSTACKi(PERLSI_MAGIC); /* crash here ~bulk88*/

my_perl->Icurstackinfo is NULL, so doing my_perl->Icurstackinfo->si_next crashes. my_perl->Icurstackinfo->si_next is part of PUSHSTACKi macro. This is a many times reported crash on perlmonks and p5p, google pushstacki and encoding.

[Anonymous Monk]

really can't wrap my head around why the first example crashes.

It is a bug. fork encoding -> Re: Parallel::ForkManager and utf8::all crash perl on Windows ( use open qw{:encoding(UTF-8) :std}; fork; ## PerlIO/encoding.dll ), Parallel::ForkManager and utf8::all crash perl on Windows

[Anonymous Monk]

#31923: use encoding "utf8" causes segfault

[wolf391]

thanks.