I noticed that DMGetOutputDM hangs when using multiple procs. The culprit is https://bitbucket.org/petsc/petsc/commits/c26acbdef0eedda92db6423afb8b38a1502ca0c8.
This doesn't work when one or more procs don't have any constraints while others have, because the ones with constraints call DMClone (collective) while the other procs don't. Thanks, Sander
