code: func (dc *DisruptionController) failSafe(pdb *policy.PodDisruptionBudget) error {
  	newPdb := pdb.DeepCopy()
  	newPdb.Status.PodDisruptionsAllowed = 0
  	return dc.getUpdater()(newPdb)
  }
docs: // failSafe is an attempt to at least update the PodDisruptionsAllowed field to
  // 0 if everything else has failed.  This is one place we
  // implement the  "fail open" part of the design since if we manage to update
  // this field correctly, we will prevent the /evict handler from approving an
  // eviction when it may be unsafe to do so.