*BSD News Article 18394


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From: gene@cs.sunysb.edu!stark (Gene Stark)
Newsgroups: comp.os.386bsd.questions
Subject: Re: KERNEL PANIC ANYONE
Date: 14 Jul 93 07:46:59
Organization: Gene Stark's home system
Lines: 21
Message-ID: <GENE.93Jul14074659@stark.uucp>
References: <22222@durer.cme.nist.gov> <1993Jul12.180752.29982@prepress.com>
NNTP-Posting-Host: stark.uucp
In-reply-to: costa@benton.prepress.com's message of 12 Jul 93 18:07:52 GMT

In article <1993Jul12.180752.29982@prepress.com> costa@benton.prepress.com (Bob Costa) writes:

>   I found that kernels in excess of 600k tend to make my system panic.

Maybe people don't know this.  I didn't, and it sure ruined one of my weekends.
When you build a kernel, it is important to use "nm" to make sure that _end
has been assigned an address strictly less than 0xFE090000.  If not, then
some of your BSS area will be overlapping the bootstrap loader.  Since the
kernel does not seem to be smart enough to zero out the overlapping area before
commencing operations, you will get panics and other strange system behavior
that is *very* difficult to debug, due to the violation of the assumption that
C programs have their BSS zeroed before they are started.

Maybe this should be in the FAQ.  It would be even better if the system
"did the right thing", but I think the problem is it's a little complicated
to figure out how/when it is safe to zero the bootstrap area.

							- Gene Stark

--
							stark@cs.sunysb.edu