12.3: "swapon -a" crashes the system

Hija,

 if you run out of swapspace and you think you might just create
some extra devices and add them to /etc/fstab and then run "swapon -a"
to enable them, don't do that.

The result might look like this:
kernel: pid 12296 (daemon), jid 5, uid 5100: exited on signal 10 (core dumped)
kernel: pid 17717 (ruby27), jid 5, uid 5100: exited on signal 6 (core dumped)
kernel: pid 14938 (daemon), jid 10, uid 5100: exited on signal 10 (core dumped)
kernel: pid 19184 (ruby27), jid 10, uid 5100: exited on signal 11 (core dumped)
kernel: pid 19182 (ruby27), jid 10, uid 5100: exited on signal 10 (core dumped)
...
with a subsequent kernel crash.

In my case I did run out of swapspace despite proper sizing, because
of unbalanced numa-domains. (Each of them may hit free_target on their
own behalf, and then start paging.)

So I did as described above, but I added them with the "late" option,
and then did run "swapon -a", which did not even add them - but
nevertheless produced the crash. The processes that do coredump might
be those that are fully swapped out?


cheerio,
PMc