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Date:      Sat, 7 Jan 1995 03:15:16 -0600 (CST)
From:      joeg@wwa.com (joe grosch)
To:        hackers@freebsd.org
Subject:   page fault while in kernel mode
Message-ID:  <m0rQXEz-000FDmC@gagme.wwa.com>

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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




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