Subsequent changes will introduce a case in which 'cb->get_cost' may not be set in em_compute_costs(), so add a check to ensure that it is not NULL before attempting to dereference it. Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Lukasz Luba <lukasz.luba@arm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>