Comment # 15 on bug 1042933 from Borislav Petkov

(In reply to Thomas Blume from comment #14)
> # strace -r -f -o /tmp/strace-test-watchdog ./test-watchdog
> Hardware watchdog 'HPE iLO2+ HW Watchdog Timer', version 0
> [58494.591725] hpwdt: tblume: reload variable is: 234

Ok, that's the hpwdt_ping() call in hpwdt_open().

> [58494.592304] hpwdt: tblume: New timer passed in is 10 seconds
> Set hardware watchdog to 10s.
> [58494.594422] hpwdt: tblume: reload variable is: 78

That looks ok too:

10 seconds * 1000 / 128 = 78.125

> [58494.594741] hpwdt: tblume: reload variable is: 78
> Pinging...
> [58494.595855] hpwdt: tblume: reload variable is: 78
> Pinging...
> [58494.597223] hpwdt: tblume: reload variable is: 78
> Pinging...
> [58499.598933] hpwdt: tblume: reload variable is: 78
> Pinging...
> [58504.600657] hpwdt: tblume: reload variable is: 78
> [58509.602239] hpwdt: tblume: reload variable is: 78
> [58509.604433] systemd-journald[376]: Sent WATCHDOG=1 notification.
> Pinging...
> [58514.603684] hpwdt: tblume: reload variable is: 78

So that's the 5 pings.

I guess you should add a pr_err() to hpwdt_pretimeout() before the
return:

    pr_err("%s: NMI raised\n", __func__);

    //tblume: suppress NMI
    return NMI_HANDLED;

so that we can see when it hits.