BUG #13643: Should a process dying bring postgresql down, or not?

The following bug has been logged on the website:

Bug reference: 13643
Logged by: Amir Rohan
Email address: amir(dot)rohan(at)mail(dot)com
PostgreSQL version: 9.5alpha2
Operating system: Linux
Description:

Seen on my box:

postgres 2181 0.0 0.1 134468 9504 pts/0 T 03:34 0:00
/usr/local/pgsql/bin/postgres -D /home/local/pg/s1
postgres 2183 0.0 0.0 134576 4168 ? Ss 03:34 0:00
postgres: checkpointer process
postgres 2184 0.0 0.0 134604 2844 ? Ss 03:34 0:00
postgres: writer process
postgres 2185 0.0 0.0 134468 2780 ? Ss 03:34 0:00
postgres: wal writer process
postgres 2186 0.0 0.0 0 0 ? Zs 03:34 0:00
[postgres] <defunct> <<<<<<<<<<<<<<< dead process
postgres 2187 0.0 0.0 127300 2204 ? Ss 03:34 0:00
postgres: stats collector process
postgres 2193 0.0 0.0 118164 2696 pts/0 T 03:34 0:00
pg_basebackup -D /home/local/pg/backup -p 57833 --format=t -x
postgres 2194 0.0 0.0 134916 6016 ? Ss 03:34 0:00
postgres: wal sender process user1 [local] sending backup "pg_basebackup
base backup"

Not sure if this is a real problem or not, but it was my understanding that
pg panics when a subprocess dies for safety resons.