Skip site navigation (1)Skip section navigation (2)
Date:      Tue, 26 Jun 2012 22:21:10 -0400
From:      Robert Simmons <rsimmons0@gmail.com>
To:        freebsd-hackers@freebsd.org
Subject:   Re: Freeze when running freebsd-update
Message-ID:  <CA%2BQLa9CCxZmDOqG%2BTS0UYTjMHcV2KCuOSzWQZ2stAR9oZj%2Bc3Q@mail.gmail.com>
In-Reply-To: <20120627005428.298430@gmx.com>
References:  <20120627005428.298430@gmx.com>

next in thread | previous in thread | raw e-mail | index | archive | help
On Tue, Jun 26, 2012 at 8:54 PM, Dieter BSD <dieterbsd@engineer.com> wrote:
> Robert writes:
>> 3) the box is responsive to hitting enter at the console (it produces
>> another login: prompt)
>
> Getty is in memory and can run.
>
>> 5) if I try to login to the console, it lets me enter a username then
>> locks up totally, it does not present me with a password: prompt.
>
> Login(1) is not in memory, and the kernel cannot read it from disk
> for some reason.
>
> I can get this symptom by writing a large file to a disk on a
> controller that FreeBSD doesn't support NCQ on. I assume there
> is a logjam in the buffer cache. Something trivial like reading
> login in from disk that would normally happen in well under a
> second can take many minutes.
>
> Perhaps geli is causing a similar logjam? Does it hang forever or
> is it just obscenely slow? If it truely hangs forever it is
> probably something else. Is there disk activity after it hangs?
> Can you try it without geli? systat -vmstat might provide a clue.

I've done some more testing with forkbomb and if I bump the memory up
to 512M I just get an error message on the console about the user
exceeding maxproc and approaching the limit on PV entries.  At that
point I'm able to Ctrl-C and stop forkbomb: no freeze.

I have a number of these instances, and I will reinstall one geli-free
and see what happens.  I will also reproduce the initial conditions
and leave it for the night to see if it comes out of it.

After a certain point there is no disk activity, and the uptime
counter in the corner of top eventially freezes too, so I don't think
it will come out of this, but we'll see.



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CA%2BQLa9CCxZmDOqG%2BTS0UYTjMHcV2KCuOSzWQZ2stAR9oZj%2Bc3Q>