Thank you for looking at this report.
You asked what is running on the machine. The first thing I want to
point out is that it's the same stack of processes that were running on
the 3.x version of the kernel; the kernel was the only upgrade. The
system is "mostly jessie" with "apt-get -t stretch install
This is a QNAP NAS, so it mostly runs a steady state of apache, nagios,
smb, cups, dnscache, mysql, postfix, slapd, and the other "regular"
daemons. In the middle of the night it'll catch an rsync request backing
up another machine on the network. These OOM reports seem to happen both
at night and during the "steady state" during the day when I'm at work
and away from the machines (this is happening on my other QNAP too).
I seem to remember the (very rare) OOM reports I'd seen in the past also
listing the process name, number, and backtrace when the process was
killed. Has the OOM reporting changed? Has page allocation changed from
3.x to 4.x to cause this? I'm not noticing that long running processes
are being killed, and I'm not seeing any other reports in the log files
of processes being killed.