Possible memory issues with 7.2.8

[albaker]

We recently upgraded multiple FortiGates (60F through 2600F) to 7.2.8 the day after the latest release was made available. Last week, one of these (60F) stopped passing traffic. We could ping the management interface and could do a "tnc -p 443 <IP>" where we'd see the 3-way handshake in a packet capture, but the login page would time out. We tried to console in - there was no prompt, but it'd echo back what we typed in. I did try an "exec reload", but nothing happened. But then, we couldn't get authenticated. This firewall required a hard reboot to bring back online. The only significant things in the system logs were these two events:

- Critical: Kernel enters memory conserve mode

- Critical: Kernel enters extreme low memory mode

This was just a few msec after an antivirus update, but I'm not certain if they are related.

We had the exact same thing happen today on another FortiGate. We have an upgrade scheduled for the main hospital this Friday, but I'm very hesitant in proceeding. I don't want any problems like this to occur. 

I can't find any bugs like this for versions around 7.2.5-7.2.8, but we do need to upgrade because of the recently announced vulnerabilities. Does anyone have information as to what might be going on, or maybe a better way to determine the root cause? 

Thank you.

[albaker]

We contacted support and confirmed this is the problem. I'm still not 100% certain, because this is the first time they saw the firewall go completely unresponsive until a reboot. Thanks for everyone's input.