dmesg shows lots of messages from serial8250:
$ dmesg | grep -i serial [ 0.884481] Serial: 8250/16550 driver, 32 ports, IRQ sharing enabled [ 6.584431] systemd: Created slice system-serial\x2dgetty.slice. [633232.317222] serial8250: too much work for irq4 [633232.453355] serial8250: too much work for irq4 [633248.378343] serial8250: too much work for irq4 ...
I have not seen this message before. What does it generally mean? Should I be worried?
(From my research, it is not distribution specific, but in case it is relevant, I see the messages on an EC2 instance running Ubuntu 16.04.)