[comp.unix.ultrix] Using dbx to panic kernel

larry@mitra.mitra.com (Larry Williamson) (04/19/91)

It seems to be quite simple to panic Ultrix 4.1 on a DEC station 5000
using dbx.

Dbx a process that does an accept(). While your process is blocked on
the accept() call, type ^C to terminate the process. Dbx responds
telling you your process has terminated, now quit dbx. Voila, panic.

This may be something peculiar to our system, but over the course of
the last few days we have done this 5 or 6 times with consistant
results.

-Larry

fortin@zap.uucp (Denis Fortin) (04/21/91)

In <LARRY.91Apr19073000@mitra.mitra.com> larry@mitra.mitra.com (Larry Williamson) writes:
>It seems to be quite simple to panic Ultrix 4.1 on a DEC station 5000
>using dbx.

>Dbx a process that does an accept(). While your process is blocked on
>the accept() call, type ^C to terminate the process. Dbx responds
>telling you your process has terminated, now quit dbx. Voila, panic.

>This may be something peculiar to our system, but over the course of
>the last few days we have done this 5 or 6 times with consistant
>results.

Arrrrrgh!

This is *not* peculiar to your system.  We have been experiencing the
same problem on our DECsystem 3100s running Ultrix 4.0!  (and 3.x before
that).

It has gotten to the point that we tell our developpers to "use printfs
instead of using dbx" (!).

Sigh...

Any workaround for this problem would be greatly appreciated.
-- 
Denis Fortin, DMR Group Inc, (514) 877-3301 (All of these opinions are my own)
fortin@zap.uucp   uunet!sobeco!zap!fortin   fortin%zap@larry.mcrcim.mcgill.edu

mjr@hussar.dco.dec.com (Marcus J. Ranum) (04/22/91)

>Dbx a process that does an accept(). While your process is blocked on
>the accept() call, type ^C to terminate the process. Dbx responds
>telling you your process has terminated, now quit dbx. Voila, panic.

	I just tried this on a 3100, running:

ULTRIX V4.1 (Rev. 52) System #2: Thu Apr 11 16:23:19 EDT 1991

	and it survived just fine. If someone can show me how to
reliably reproduce the problem, I'll QAR it, but I can't until it's
something I can duplicate.

mjr.

neideck@cloris.enet.dec.com (Burkhard Neidecker-Lutz) (04/22/91)

It was a strange kernel bug that is fixed in Ultix 4.2. Bit us too...

			Burkhard Neidecker-Lutz, CEC Karlsruhe