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Date: Fri, 22 May 1998 10:00:39 +0400 (MSD)
From: Alex Povolotsky <tarkhil@asteroid.svib.ru>
Reply-To: tarkhil@asteroid.svib.ru
To: FreeBSD-gnats-submit@freebsd.org
Subject: mount_msdos+mount_null+mc=panic
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>Number:         6719
>Category:       bin
>Synopsis:       mount_msdos+mount_null+mc=panic
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    gnats-admin
>State:          closed
>Quarter:        
>Keywords:       
>Date-Required:  
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu May 21 23:00:02 PDT 1998
>Closed-Date:    Sat May 23 20:06:18 PDT 1998
>Last-Modified:  Thu Jul 01 05:40:37 GMT 2004
>Originator:     
>Release:        
>Organization:
>Environment:
>Description:
>How-To-Repeat:
>Fix:
>Release-Note:
>Audit-Trail:
State-Changed-From-To: open->closed 
State-Changed-By: steve 
State-Changed-When: Sat May 23 20:06:18 PDT 1998 
State-Changed-Why:  
Duplicate of 6706. 
>Unformatted:
Synopsis: mount_null can cause panic when mounting DOS disks
Severity:       serious
Category:       kern
Release:        FreeBSD 3.0-SNAP-980217 i386
Class:          sw-bug
Environment: 
FreeBSD from 2.2.2-RELEASE at least; maybe earler.
Midnight Commander 4.XX
FAT partition

Description: 

Attempt to view any file on mount_null'ed mount_msdos'ed disk with Midnight
Commander cause the following:

Fatal trap 12: page fault while in kernel mode
fault virtual address   = 0xc
fault code              = supervisor read, page not present
instruction pointer     = 0x8:0xf013c1ea
stack pointer           = 0x10:0xf417ddb8
frame pointer           = 0x10:0xf417ddb8
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, def32 1, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 3431 (midc)
interrupt mask          = 
trap number             = 12
panic: page fault

syncing disks... 20 20 17 12 3 done

How-To-Repeat: 

mount (with -t msdos) any DOS disk;
mount (using mount_null) any subdirectory of it;
start Midnight Commander and try to view (pressing F3) any file in
mount_null'ed directory

Watch the panic
