Old laptop not able to get enough entropy in FreeBSD 11

Jack L. xxjack12xx at gmail.com
Sun Nov 27 00:20:19 UTC 2016


On Sat, Nov 26, 2016 at 7:01 AM, Bertram Scharpf <lists at bertram-scharpf.de>
wrote:

> On Friday, 25. Nov 2016, 20:06:55 -0800, Jack L. wrote:
> > On Fri, Nov 25, 2016 at 7:32 PM, Bertram Scharpf <
> lists at bertram-scharpf.de>
> > wrote:
> >
> > > On Friday, 25. Nov 2016, 18:31:24 -0800, Jack L. wrote:
> > > > >> > I have an old single core AMD Turion ML-37 laptop that has
> nothing
> > > > >> > installed. When I boot it up, the moment it displays login:, it
> hangs
> > > > >> > until i press some random keys. At shutdown, it will hang until
> I
> > > > >> > press keys and it will not move onto the next line of shutdown
> until
> > > > >> > I keep pressing keys.
> > > > >> >
> > > > >> > If I cat /dev/random > ./dev/null while using the laptop, it
> works
> > > > >> > fine but when nothing is happening, the laptop hangs. Any
> ideas? It's
> > > > >> > running 11.0-STABLE
> > > > >
> > > > > Any ideas on why the laptop would have that behavior in 11? It
> didn't hang
> > > > > at all in 10.3-STABLE
> > > > >
> > > > I just installed 12-CURRENT on the laptop and it also hangs even at
> > > > install/boot/shutdown until I hit keys, then it will move as long as
> I
> > > > continue to hit keys. I also found that if I ping the laptop, it will
> > > > respond but in between pings, it will hang. Using FreeBSD 10.3, it
> works
> > > > perfectly fine without any random keypresses. Any ideas?
> > >
> > > I'm convinced this behaviour it worth being analysed.
> > >
> > > Can you gain any knowlegde by calling cat through truss?
> >
> > How should I run that?
>
> Sorry, that was probably too fast.
>
> You could run one of those:
>
>   # truss cat /dev/random >/dev/null
>   # truss dd if=/dev/random of=/dev/null bs=512 count=3
>
> But they will show just a series of read-write calls until a
> read will hang. The detain presumably occurs in the random
> device. That's kernel stuff. Does anybody have a hint how to
> debug that without influencing the behaviour in question?
>

So truss cat /dev/random >/dev/null
will keep going and going and going and going
truss dd if=/dev/random of=/dev/null bs=512 count=3
sits there and hangs with no activity until i hit a key, then the dd
happens.


> Bertram
>
>
> --
> Bertram Scharpf
> Stuttgart, Deutschland/Germany
> http://www.bertram-scharpf.de
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