From zach@blizzard.gaffaneys.com  Fri Feb 14 14:06:56 1997
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Date: Fri, 14 Feb 1997 16:06:43 -0600 (CST)
From: Zach Heilig <zach@blizzard.gaffaneys.com>
Reply-To: zach@blizzard.gaffaneys.com
To: FreeBSD-gnats-submit@freebsd.org
Subject: Kernel crashes when you mount more than one device on a mount point (oops!)
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>Number:         2738
>Category:       kern
>Synopsis:       [DEVFS problem] Kernel crashes when you mount more than one device on a mount point (oops!)
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    julian
>State:          closed
>Quarter:
>Keywords:
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Fri Feb 14 14:10:01 PST 1997
>Closed-Date:    Sat May 3 23:21:21 MET DST 1997
>Last-Modified:  Sat May  3 23:24:07 MET DST 1997
>Originator:     Zach Heilig
>Release:        FreeBSD 2.2-ALPHA i386
>Organization:
none
>Environment:

AMD 5x86-133, 20 Meg ram, 411 Meg sd0, 2.1 Gig sd1 running
2.2-ALPHA.

>Description:

I mounted devfs on /mnt, then mounted /dev/sd1c on /mnt
(forgot about devfs).  Then, when I tried to umount, the
machine did a cold boot (no panic).  I was trying to
configure sd1 to eventually be sd0 (finally figured it out).

	

>How-To-Repeat:

mount_devfs devfs /mnt
mount /dev/sd1c /mnt
umount devfs # message saying devfs wasn't mounted...
umount /mnt # probably not what I _should_ have done, but...
            # instant cold boot (no panic).
	

>Fix:

don't mount two different devices on the same mount point...	

	

>Release-Note:
>Audit-Trail:
State-Changed-From-To: open->closed 
State-Changed-By: jmg 
State-Changed-When: Fri Feb 14 19:02:05 PST 1997 
State-Changed-Why:  
originator confirms closure because real bug is with umounting devfs 
State-Changed-From-To: closed->open 
State-Changed-By: mpp 
State-Changed-When: Sat Feb 15 23:25:25 PST 1997 
State-Changed-Why:  
Re-opened because there is still a devfs problem here, 
and there are no other PRs open on that problem. 


Responsible-Changed-From-To: freebsd-bugs->julian 
Responsible-Changed-By: mpp 
Responsible-Changed-When: Sat Feb 15 23:25:25 PST 1997 
Responsible-Changed-Why:  
Devfs is Julian's baby. 
State-Changed-From-To: open->closed 
State-Changed-By: joerg 
State-Changed-When: Sat May 3 23:21:21 MET DST 1997 
State-Changed-Why:  
Suggested fixes from PR # 3276 and 3469 applied, in rev 1.36 and 
1.17 of devfs_tree.c, and devfs_vfsops.c, respectively. 

Thanks for the fixes! 

(There are still problems regarding the final umount, but the kernel 
doesn't crash anymore.) 
>Unformatted:
 
