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Date:      Thu, 2 May 1996 15:58:24 -0400 (EDT)
From:      "Marc G. Fournier" <scrappy@ki.net>
To:        Peter Wemm <peter@freefall.freebsd.org>
Cc:        CVS-committers@freefall.freebsd.org, cvs-all@freefall.freebsd.org, cvs-sys@freefall.freebsd.org
Subject:   Re: cvs commit:  src/sys/kern kern_fork.c
Message-ID:  <Pine.NEB.3.93.960502155813.22809C-100000@freebsd.ki.net>
In-Reply-To: <199605021138.EAA18666@freefall.freebsd.org>

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so maybe it wasn't *all* hardware? :)


On Thu, 2 May 1996, Peter Wemm wrote:

> peter       96/05/02 04:38:06
> 
>   Modified:    sys/kern  kern_fork.c
>   Log:
>   Fix a nasty bug that causes random crashes and lockups particularly on
>   very busy servers (eg: news, web).  This is an interaction between
>   embryonic processes that have not yet finished forking, and happen to
>   cause the kernel VM space to grow, hitting the uninitialised variable.
>   
>   It was possible for this to strike at any time, depending on the size of
>   your kernel and load patterns.  One machine had paniced occasionally
>   when cron launches a job since before the 2.1 release.
>   
>   If you had "options DIAGNOSTIC", you may have seen references to bogus
>   addresses like 0xdeadc142 and the like.
>   
>   This is a minimal change to fix the problem, it will probably be done
>   better by reordering p_vmspace to be in the startzero section, but it
>   becomes harder to validate then.
>   
>   It's been vulnerable since pmap.c rev 1.40 (Jan 9, 1995), so it's been a
>   cause of problems since well before 2.0.5.  This was when the merged
>   VM/buffer cache and the dynamic growing kernel VM space were first
>   committed.  This probably fixes a few of PR's.
>   
>   Revision  Changes    Path
>   1.21      +6 -1      src/sys/kern/kern_fork.c
> 

Marc G. Fournier                                  scrappy@ki.net
Systems Administrator @ ki.net               scrappy@freebsd.org




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