A physics list including G4EMDissociation will get a segmentation fault when exit.

The destructor of G4EMDissociation delete the cross section object.
However, the base class G4VCrossSectionDataSet delete the cross section object again.  

G4EMDissociation::~G4EMDissociation ()
{
  if (handlerDefinedInternally) delete theExcitationHandler;
  delete dissociationCrossSection;   <-- this line
  delete thePhotonSpectrum;
}

G4VCrossSectionDataSet::~G4VCrossSectionDataSet()
{
  G4CrossSectionDataSetRegistry::Instance()->DeRegister(this); <-- delete again
}