beta6/7 machine freeze

Hi folks!

Back from a one week vacation, I immediately updated my machine to BETA
7. Before I left, my machine had panics serveral times a day. Since BETA
6 the panics are gone but the machine locked up a few times (experienced
two days before I left for a week). The machine freeze has been mostly
while hanging up or shortly after a ppp (userland) connection has been
hang up.

Now I've updated to BETA 7 and the machine seem to lock up faster. The
machine freezes most times while having an established ppp connection to
the public internet. The machine is acting as a router, dial-up client,
proxy, mailserver, webserver etc. etc.

When the machine locks up, there's no console or network response from
the machine. The only way out is the reset switch.

One of my guesses has been that either i4b or userland ppp is causing
the machine freeze. To figure out if that might be the case, I've set up
a 2nd machine (releng_4) acting as a dial-up client (i4b/ppp) and
router. The 2nd machine is now being used as a default route for the
server machine.

Since using that test setup the server machine didn't had a lockup. So
my guess might be probably right to have a problem somewhere at i4b or
user-ppp in releng_5.

How does one debug a dead machine? Is there any way to get a backtrace
or call the debugger while the machine has been frozen?

Thanks,

Volker

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