Critical When upgrading from 1.3.14 to 1.3.15 the signer listed 0 zones to work on. When accessing the newly upgraded debug-locks, the listing process blocked at the point shown below.
The signer had to be kill-9'd before it would be done. Going back to 1.3.14 gave the same problem there, and jumping back up to 1.3.15 still did it. It looks like a reproducible problem. The zone list I made at some point was not empty, but very much shorter than it ought to be – is it slowly loading and/or blocked due to the debug-locks command getting stuck?
The problem disappeared after vacuuming the /var/opendnssec/tmp/ directory.