I did this successfully between a content handler and a cleanup handler, the major difference is that I have both handlers in the same package thusly:

sub conthandler
{
  $r = shift;
                tie %CORE::GLOBAL::testdb, 'BerkeleyDB::Hash',
                    -Filename => 'testdb',
                    -Flags => 'DB_RDONLY'
                    or die "cannot open bdb $!$BerkleleyDB::Error";
  
  print join ',',keys %CORE::GLOBAL::testdb;
  $r->register_cleanup(\&cleanuphandler);
}

sub cleanuphandler
{
  my $r = shift;
  die unless scalar keys %CORE::GLOBAL::testdb;
  # doesn't die
}
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