#!/usr/bin/env perl

use strict;
use warnings;

$SIG{__DIE__} = sub {
    if ($^S == 0) {
        for my $s (0..$#_) {
            dcs($_[$s]);
        };
    }
};

sub dcs
{
  my ($p1, $p2) = @_;
  my $cs='';
  for (my $i=1; $i<3; $i++) {
    my ($package, $filename, $line, $subroutine) = caller($i);
    last if ( ! defined($package) );
    print STDERR $filename;
  }
  print STDERR $p1;
}

sub mysub
{
    die;
}

binmode STDERR, ":encoding(koi8-r)";
mysub();
1;

[download]
This code just hangs if path to perl program contain UTF-8 characters (like 'perl тест/poc.pl').

It can reproduce it on two linux boxes (perl 10 and perl 12). Both have UTF-8 locale, UTF-8 filenames.

I hangs with different single-byte encodings (i tried koi-8 and cp1251). It hangs only when STDERR used and only when die is inside mysub.

The reason why I am trying to debug such a weird code in these weird circumstances - I have another script with similar code and a user with similar problem, however I cannot reproduce his problem in full. So I came to this PoC - I think maybe it's related.

Also this user does not do fancy things like using non-ASCII characters in filenames or using encoding different from locale encoding. However he runs FreeBSD and his locale is koi8-r (and my program sets STDERR encoding to KOI-8 too)

UPD: Perl hangs with 100% CPU usage and strace hangs with: 
open("/usr/lib/perl/5.10/auto/Encode/Byte/Byte.so", O_RDONLY) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\240\\\3\0\0\0\
+0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0644, st_size=375048, ...}) = 0
mmap(NULL, 2470176, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
+ 0) = 0x7fcef2b27000
mprotect(0x7fcef2b62000, 2093056, PROT_NONE) = 0
mmap(0x7fcef2d61000, 139264, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIX
+ED|MAP_DENYWRITE, 3, 0x3a000) = 0x7fcef2d61000
close(3)                                = 0
mprotect(0x7fcef2d61000, 135168, PROT_READ) = 0

[download]
UPD: Shortest PoC: 
#!/usr/bin/env perl
use strict;
use warnings;
use Carp;
$SIG{__DIE__} = sub { print STDERR $_ for (@_); };
binmode STDERR, ":encoding(koi8-r)";
sub mysub {    croak; }
mysub();
1;

[download]
Again, should be ran as 'perl тест/poc.pl'. In this version die() does not reproduce problem - only 'croak'. Also cp1251 works without problem.

In reply to Weird STDERR/SIGDIE/Encodings issue by vsespb

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