From owner-freebsd-hackers  Sat Jan  7 01:04:58 1995
Return-Path: hackers-owner
Received: (from root@localhost) by freefall.cdrom.com (8.6.9/8.6.6) id BAA17842 for hackers-outgoing; Sat, 7 Jan 1995 01:04:58 -0800
Received: from gagme.wwa.com (root@gagme.wwa.com [198.49.174.33]) by freefall.cdrom.com (8.6.9/8.6.6) with SMTP id BAA17836 for <hackers@freebsd.org>; Sat, 7 Jan 1995 01:04:55 -0800
Received: by gagme.wwa.com (Smail3.1.28.1 #8)
	id m0rQXEz-000FDmC; Sat, 7 Jan 95 03:15 CST
Message-Id: <m0rQXEz-000FDmC@gagme.wwa.com>
From: joeg@wwa.com (joe grosch)
Subject: page fault while in kernel mode
To: hackers@freebsd.org
Date: Sat, 7 Jan 1995 03:15:16 -0600 (CST)
X-Mailer: ELM [version 2.4 PL23]
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Content-Length: 1273      
Sender: hackers-owner@freebsd.org
Precedence: bulk

Well,

    I've recompiled the kernel with kernel debug options and now have the 
problem to the point that I can consistently reproduce this problem.

    I start a tar listing of a tape and push it into the background ie. 

        tar tvf /dev/rwt0 > tape.list &

    I then start up emacs and crank up gdb under emacs. gdb starts up fine
altho I can hear that the disk is VERY busy. As soon as try to run the program
inside gdb I get a page fault. I get dropped into the kernel debugger. 
I am not very good with the kernel debugger but I do a trace and the debugger
tells me the following;

        _pmap_enter( ... )
        _vm_fault( ... )
        _pwrite( ... )
        _ptrace( ... )
        _syscall( ... )

    Has anyone else gotten to this point? Have I stumbled over an old bug?
or is this a new bug. My source is WC's CDROM (FreeBSD2.0). My system is a 
386SX40 with 4 meg of memory, a one gig SCSI disk with 50 meg of swap. 
I'll write up a more complete discription of the results of the kernel debug 
session tomorrow (It's 3am). 


Josef
-- 
  __/\__  |  Josef Grosch    |  "It's been a quiet week in Lake
  \    /  |  (708) 291-9076  |  Wobegon, my home town..."
  /_  _\  |                  | 
    \/    |  joeg@wwa.com    |  -Prairie Home Companion