The first two arguments of IO::Select->select are rarely the same, so I'm not sure that's a useful patch. In fact, the first two arguments should be different in your code. (Why are you waiting to write to the listen socket?) It should look more like:

my $rsel = IO::Select->new();
my $wsel = IO::Select->new();

...

for (;;) {
   my ($rready, $wready) = IO::Select->select($rsel, $wsel);

   foreach my $rsocket (@$rready) {
      ...
   }

   foreach my $wsocket (@$wready) {
      ...
   }
}
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