BUG #14420: Parallel worker segfault

The following bug has been logged on the website:

Bug reference: 14420
Logged by: Rick Otten
Email address: rotten(at)windfish(dot)net
PostgreSQL version: 9.6.1
Operating system: Ubuntu 16.04
Description:

This just happened on my production 9.6.1 system:

2016-11-11 21:31:26.215 UTC LOG: worker process: parallel worker for PID
1737 (PID 6792) was terminated by signal 11: Segmentation fault
2016-11-11 21:31:26.215 UTC LOG: terminating any other active server
processes

I had a lot of stuff running concurrently, so I'm not sure which query
caused the failure. There is nothing else obvious or illuminating in the
logs that I can see. After it recovered, everything went back to normal.

I figured I should report this even if I don't have much to go on yet.

Is there a core file somewhere that would be of help? (I'm not seeing
one.)

Should I turn up debug or enable something to catch more information if it
happens again?

select version();
version
----------------------------------------------------------------------------------------------------------
PostgreSQL 9.6.1 on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu
5.3.1-14ubuntu2) 5.3.1 20160413, 64-bit