lldpd can return negative age

[vivekrnv]

admin@sonic:~$ lldpctl -v
1.0.4

Bug description

lldpd returned negative age because of the late time sync by ntpd

hwclock of the system was set to future, lldpd process started before the ntpd could re-adjust the time back.

Negative age is seen because the hwclock of the system being forward in time and the system time is later reset to correct time by ntpd. But the lldp agent for one of the interfaces started before ntpd sync and thus the init time is forward in time causing the age to be negative.

{
    "lldp": {
        "interface": {
            "eth0": {
                "via": "LLDP",
                "rid": "1",
                "age": "-2 day, -23:-59:-47",
            }
       }
}