ssh sessions close spontaneously on rpi2

[Mark Millard]

On 2017-Nov-21, at 1:15 PM, Mark Millard <markmi at dsl-only.net> wrote:

> On 2017-Nov-20, at 8:58 AM, bob prohaska <fbsd at www.zefox.net> wrote:
> 
>> Can anybody reproduce the following behavior on RPI2 ?
>> 
>> Boot the machine multi-user and start two ssh login sessions.
>> 
>> On one, start a top session, as a placeholder. On the second,
>> su to root, cd to /usr/ports and run
>> make -j8 clean > clean.log &
>> 
>> Next, try to open another (this makes three) ssh connection. Log in,
>> and just watch. 
>> 
>> On my test box at FreeBSD 12.0-CURRENT (RPI2) #10 r325987 the connection
>> fails within a couple of minutes; the login session terminates without
>> explanation and the connection closes. 
>> 
>> No errors are on the serial console, /var/log/messages records nothing
>> related. Ssh sessions started prior to starting make clean seem unaffected.
> 
> Given the messages that I've been getting but you have not,
> I figure my attempting this under my current conditions
> would not be effective.
> 
> 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.
> 
> The process CPU column agrees, in that that the total is
> around 300% instead of around 400%. A couple of the
> tend to show closer to 50% as long as 4 are running.
> At 3 running it goes back to each being near 100%.
> 
> # uname -apKU
> FreeBSD rpi2 12.0-CURRENT FreeBSD 12.0-CURRENT  r325700M  arm armv7 1200053 1200053
> 
> (I normally run a non-debug kernel that has debug symbols.)
> 
> I may try jumping to -r325997 .
> 

I rebooted and ended up stuck at Releasing APs.

I cut and restored power and booted. And now
all the cores seem to be in use.

Still -r325700 .

Not easily repeatable from what I can tell.

A question for your test: what if you substitute
computation-bound processes for your -j8 make?
Do you get different results?

===
Mark Millard
markmi at dsl-only.net