Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!samsung!umich!sharkey!fmsrl7!art-sy!news
From: chap@art-sy.detroit.mi.us (j chapman flack)
Newsgroups: comp.unix.sysv386
Subject: Kernel core dumps (was Re: out of swap space??)
Summary: Where they go, how to analyze them, how to make them
Keywords: kernel core dumps crash forced panic
Message-ID: <9105031411.aa04050@art-sy.detroit.mi.us>
Date: 3 May 91 18:11:52 GMT
References: <1991Apr23.214037.16410@netcom.COM> <1991Apr24.165943.7202@rfengr.com> <450@bartal.BARTAL.COM>
Sender: chap@art-sy.detroit.mi.us (j chapman flack)
Reply-To: chap@art-sy.detroit.mi.us (j chapman flack)
Organization: Appropriate Roles for Technology
Lines: 34

In article <450@bartal.BARTAL.COM> phillip@BARTAL.COM (Phillip M. Vogel) writes:
>When the kernel dumps core, it puts the core dump into the swap
>area ON THE PRIMARY DISK. Well, 8 megs of core dump into 5 megs

This reminded me of questions I've been meaning to ask.  I never knew where
the kernel core dump goes in a panic (and so far I've had no opportunity to
find out....).  This posting suggests it goes in the swap area, but that
brings up an immediate question:

  At what point does the kernel begin using the swap area on the next boot??
  How am I able to use `crash' to examine the core dump before the evidence
  is overwritten?  Or does something check for the presence of a core dump
  in the swap area at boot time and copy it to a file for later examination?
  In that case, my first question is back: Where does it go?

Here's another question: when I first installed this system, it would
constantly overflow the kernel file and inode tables, causing all sorts
of programs to fail unpredictably.  At the time, I didn't know if the
default table sizes were preposterous or if some runaway bug was filling the
tables.  It would have been handy to be able to run something as root that
forces a panic, then reboot and analyze the dump while the system is still
reasonably reliable.  Sort of like running OPCCRASH from the console on
a VAX.  Does anybody have a panic-forcing program?  This is SCO SysV 3.2.

(Btw, it turned out the table sizes were preposterous.  They came out of the
box ready to accommodate about as many files and inodes as the daemons have
open before I log in....)

Thanks!
-- 
Chap Flack                         Their tanks will rust.  Our songs will last.
chap@art-sy.detroit.mi.us                                   -Mikos Theodorakis

Nothing I say represents Appropriate Roles for Technology unless I say it does.