Comm_spawn was sticking during spawn_multiple because of a problem in the dpm - the modex there is asking processes to talk to each other in an allgather_list operation, but the procs don't have the required contact info to do so. The solution here was to ensure that all parent procs have full contact info for procs in the child job.
Admittedly, this isn't the long-term answer. We would like to have the contact info given to only the parent procs that were involved in the comm_spawn. There is a way to do that, but this will suffice to keep things working until that can be implemented and tested.
This commit was SVN r17772.
b110a247be