That's something in the VM subsystem. The time of the dump was Tue Jun 28 08:03:43 2016 (in the system's configured timezone), and appears to be on the kernel from prior to the upgrade. Was that about the time it rebooted post-upgrade?
The closest semi-related crash I can find is this.
It's not the same as that, but does appear it might be md-related in your case. You using /var as a RAM disk? It something that's repeatable if you reboot the system, or upgrade again?