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.rohan@mail.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.