Here are my test scripts, trimmed down to the bare minimum showing this behavior:

Reader:

#!/usr/bin/perl

use strict;
use warnings;

use IO::Socket::UNIX;

my $SOCK  = '/home/lomig/dev/imliner/run/tst.sock';
unlink $SOCK if -e $SOCK;

my $read = IO::Socket::UNIX
  ->new (
         Local => $SOCK,
         Listen=> SOMAXCONN,
         Type => SOCK_STREAM,
         Reuse =>1,
    );
$read || die "No read socket: $!\n";
print 'Read inode = ',  (stat($read->hostpath()))[1], "\n";
  
my  $client = $read->accept();
while (<$client>) {
  print "read: $_";
  last if $_ =~ /2/; #exit after 3rd message
}
$client->close();
$read->close();


exec $0; # restart itself
[download]

Writer:

#!/usr/bin/perl

use strict;
use warnings;

use IO::Socket::UNIX;

my $write = IO::Socket::UNIX
  ->new(
    Peer => '/home/lomig/dev/imliner/run/tst.sock',
    Type => SOCK_STREAM,
       ) ;
$write || die "No write socket: $!\n";


for (0..2) {
  print 'Write connected? ', $write->connected() ? 'yes' : 'no', "\n";
  print 'Write opened? '   , $write->opened() ? 'yes' : 'no', "\n";
  print 'Write errored? '  , $write->error() ? 'yes' : 'no', "\n";
  print 'Write peerpath: ' , $write->peerpath(), "\n";
  print'inode : '          , (stat($write->peerpath()))[1], "\n";
  foreach my $i (0..2) {
    eval {print $write "Hi $i\n";};
    if ($@) {print "Write issue: $@\n";} # *never* reached
  }
  print "Go to sleep while the reader restarts itself, then loop again
+\n";
  sleep 2;
}

$write->close();
[download]

Writer's output:

Write connected? yes
Write opened? yes
Write errored? no
Write peerpath: /home/lomig/dev/imliner/run/tst.sock
inode : 1517896
Go to sleep while the reader restarts itself
Write connected? yes
Write opened? yes
Write errored? no
Write peerpath: /home/lomig/dev/imliner/run/tst.sock
inode : 1517896
[download]

And that's it, not segfault, exception, nothing.

I am using perl 5.10.0-23 on debian unstable, up to date.

Thank you very much for any help or pointer to help me understand this.