5.4 Hanging, have some DDB output, unable to get panic dump

[David Kirchner]

On 10/3/05, Philip Kizer <pckizer at nostrum.com> wrote:
> Thanks for the response, from what I'm finding from my search, it
> looks like you mean this:
>
> http://lists.freebsd.org/mailman/htdig/freebsd-stable/2005-August/
> 017607.html
>
> and the referenced patch:
>
> http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/i386/i386/pmap.c.diff?
> r1=1.523&r2=1.524&f=h
>
>
> But, the version I'm running as listed above shows to have pmap.c:
>
> __FBSDID("$FreeBSD: src/sys/i386/i386/pmap.c,v 1.494.2.10 2005/08/08
> 15:33:53 jhb Exp $");
>
> which already has the new code (and I'm having a hang, not the panic
> that was described without that patch).

Oh, okay. I didn't realize 5.4-STABLE had it (RELENG_5_4 is a lot
further down on that pmap.c.diff page). I also mistakenly thought it
was a panic issue.

> FYI: Just to describe the hang a bit more, I do get some response
> from the machine, it just cannot do any useful work.  For instance,
> on the console:
>
>      If I hit return at "login:", I get a new "login:" prompt, but as
> soon as I enter a username+^M or Ctrl-D it, I cease to receive any
> feedback besides terminal echo from my input.
>
>      If I'm logged in on the console I can even hit return in the
> shell and get a new shell prompt, but any command I try (i.e.
> 'uptime' or 'uname') then results in the same lack of any further
> response.
>
>      Plus, I cannot DDB "db> panic" the box as that then produces a
> hard-hang, so no sync+core and then I don't even get tty echo from my
> input.

I can't explain that one. I've seen it happen before when a drive
"disappears", but there are usually additional signs, such as errors
sent to the console. Sorry about the misdirection!