The "status=139" error must have something to do with having multiple, conflicting versions of PHP enabled.
I am running 18.04 and an old PHP site I run only locally ceased to work. I am guessing aptitude installed and enabled php7.2, possibly when I installed kubuntu-desktop a few weeks back.
Regardless, I had two versions of PHP enabled:
$ cd /etc/apache2/
$ l mods-*/php*
-rw-r--r-- 1 root root 867 Jun 9 2017 mods-available/php5.6.conf
-rw-r--r-- 1 root root 102 Jun 9 2017 mods-available/php5.6.load
-rw-r--r-- 1 root root 867 Mar 2 2017 mods-available/php7.0.conf
-rw-r--r-- 1 root root 102 Oct 1 2018 mods-available/php7.0.load
-rw-r--r-- 1 root root 855 Jul 7 2017 mods-available/php7.1.conf
-rw-r--r-- 1 root root 102 Jul 7 2017 mods-available/php7.1.load
-rw-r--r-- 1 root root 855 Feb 8 2019 mods-available/php7.2.conf
-rw-r--r-- 1 root root 102 Feb 8 2019 mods-available/php7.2.load
lrwxrwxrwx 1 root root 29 Jul 1 2017 mods-enabled/php5.6.conf -> ../mods-available/php5.6.conf
lrwxrwxrwx 1 root root 29 Jul 1 2017 mods-enabled/php5.6.load -> ../mods-available/php5.6.load
lrwxrwxrwx 1 root root 29 May 28 06:05 mods-enabled/php7.2.conf -> ../mods-available/php7.2.conf
lrwxrwxrwx 1 root root 29 May 28 06:05 mods-enabled/php7.2.load -> ../mods-available/php7.2.load
In my case, I am fine with using php5.6, because the site is not online and is purely for my local use only. So disabling 7.2 did the trick:
sudo a2dismod php7.2
Now my php mods-enabled are less confusing to apache3:
$ l mods-*/php*
-rw-r--r-- 1 root root 867 Jun 9 2017 mods-available/php5.6.conf
-rw-r--r-- 1 root root 102 Jun 9 2017 mods-available/php5.6.load
-rw-r--r-- 1 root root 867 Mar 2 2017 mods-available/php7.0.conf
-rw-r--r-- 1 root root 102 Oct 1 2018 mods-available/php7.0.load
-rw-r--r-- 1 root root 855 Jul 7 2017 mods-available/php7.1.conf
-rw-r--r-- 1 root root 102 Jul 7 2017 mods-available/php7.1.load
-rw-r--r-- 1 root root 855 Feb 8 2019 mods-available/php7.2.conf
-rw-r--r-- 1 root root 102 Feb 8 2019 mods-available/php7.2.load
lrwxrwxrwx 1 root root 29 Jul 1 2017 mods-enabled/php5.6.conf -> ../mods-available/php5.6.conf
lrwxrwxrwx 1 root root 29 Jul 1 2017 mods-enabled/php5.6.load -> ../mods-available/php5.6.load
Naturally for a live site one would want to disable php-5.6 and leave the php7.2 enabled, because you should run the newer version in real life.
sudo a2dismod php5.6
sudo a2enmod php7.2
Then the php mods should look like this:
$ l mods-*/php*
-rw-r--r-- 1 root root 867 Jun 9 2017 mods-available/php5.6.conf
-rw-r--r-- 1 root root 102 Jun 9 2017 mods-available/php5.6.load
-rw-r--r-- 1 root root 867 Mar 2 2017 mods-available/php7.0.conf
-rw-r--r-- 1 root root 102 Oct 1 2018 mods-available/php7.0.load
-rw-r--r-- 1 root root 855 Jul 7 2017 mods-available/php7.1.conf
-rw-r--r-- 1 root root 102 Jul 7 2017 mods-available/php7.1.load
-rw-r--r-- 1 root root 855 Feb 8 2019 mods-available/php7.2.conf
-rw-r--r-- 1 root root 102 Feb 8 2019 mods-available/php7.2.load
lrwxrwxrwx 1 root root 29 May 29 17:43 mods-enabled/php7.2.conf -> ../mods-available/php7.2.conf
lrwxrwxrwx 1 root root 29 May 29 17:43 mods-enabled/php7.2.load -> ../mods-available/php7.2.load
Don't forget to resatart the server!
systemctl restart apache2
Thanks to Pavel's comment for inspiring this line of research!