ssh sessions close spontaneously on rpi2

[bob prohaska]

On Tue, Nov 21, 2017 at 01:15:05PM -0800, Mark Millard wrote:
> 
> But I've another oddity that you might try:
> 
> A) I booted and ran top on the serial console ( top -CaePosize )
> B) I logged in 4 ssh sessions and had each do "openssl speed"
> 
> top gets an unexpected result: CPU 2 shows as 100% idle and the
> others 0.0% idle.
> 
On
 
FreeBSD 12.0-CURRENT (RPI2) #11 r326038: Wed Nov 22 01:04:56 PST 2017

the behavior seems reasonable:

last pid:   743;  load averages:  3.88,  2.12,  0.97    up 0+00:35:32  08:51:39
28 processes:  5 running, 23 sleeping
CPU: 97.3% user,  0.0% nice,  0.6% system,  2.2% interrupt,  0.0% idle
Mem: 22M Active, 4380K Inact, 65M Wired, 33M Buf, 824M Free
Swap: 2048M Total, 2048M Free

  PID USERNAME    THR PRI NICE   SIZE    RES STATE   C   TIME    WCPU COMMAND
  739 bob           1 102    0  7404K  4496K CPU3    3   3:56 103.68% openssl
  737 bob           1 103    0  7404K  4496K RUN     2   4:16  99.53% openssl
  741 bob           1 103    0  7404K  4496K CPU1    1   2:25  98.15% openssl
  740 bob           1 102    0  7404K  4496K CPU0    0   3:47  92.67% openssl
  694 bob           1  20    0  6508K  3060K CPU2    2   0:02   0.42% top
  714 bob           1  20    0 11188K  6756K select  2   0:00   0.05% sshd
  706 bob           1  20    0 11188K  6756K select  2   0:00   0.04% sshd
  603 root          1  20    0  8156K  5096K select  1   0:00   0.02% sendmail
 
Far as I can tell the problems with ssh disconnection are tied to 
running make -jN processes in /usr/ports.  Make -j4 buildworld in /usr/src 
does not obviously interfere with subsequent ssh connections. 

Running make -j4 -DBATCH in /usr/ports/www/firefox also breaks ssh connections, 
but not quite so fast, it takes a few minutes for new ssh sessions to fail.
Incidentally, the -DBATCH flag is ignored.

That make stopped on a stale readline installation. After manually upgrading
readline, the make was restarted without -j4 in /usr/ports/www/firefox and,
some ten minutes later, the ssh connections are still working.

Looks like the trouble is related to make -jN, but only in /usr/ports. It's
understood the -j option is not a sure thing in ports, but having it 
interfere with ssh connections seems most strange.

Thanks for reading,

bob prohaska