From nobody@FreeBSD.org  Thu Oct  4 18:55:55 2012
Return-Path: <nobody@FreeBSD.org>
Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52])
	by hub.freebsd.org (Postfix) with ESMTP id 332C11065672
	for <freebsd-gnats-submit@FreeBSD.org>; Thu,  4 Oct 2012 18:55:55 +0000 (UTC)
	(envelope-from nobody@FreeBSD.org)
Received: from red.freebsd.org (red.freebsd.org [IPv6:2001:4f8:fff6::22])
	by mx1.freebsd.org (Postfix) with ESMTP id 1E3448FC08
	for <freebsd-gnats-submit@FreeBSD.org>; Thu,  4 Oct 2012 18:55:55 +0000 (UTC)
Received: from red.freebsd.org (localhost [127.0.0.1])
	by red.freebsd.org (8.14.5/8.14.5) with ESMTP id q94ItswC041359
	for <freebsd-gnats-submit@FreeBSD.org>; Thu, 4 Oct 2012 18:55:54 GMT
	(envelope-from nobody@red.freebsd.org)
Received: (from nobody@localhost)
	by red.freebsd.org (8.14.5/8.14.5/Submit) id q94ItscN041341;
	Thu, 4 Oct 2012 18:55:54 GMT
	(envelope-from nobody)
Message-Id: <201210041855.q94ItscN041341@red.freebsd.org>
Date: Thu, 4 Oct 2012 18:55:54 GMT
From: Garrett Cooper <yaneurabeya@gmail.com>
To: freebsd-gnats-submit@FreeBSD.org
Subject: unionfs permits recursive union mounts; causes panic quickly
X-Send-Pr-Version: www-3.1
X-GNATS-Notify:

>Number:         172334
>Category:       kern
>Synopsis:       [unionfs] unionfs permits recursive union mounts; causes panic quickly
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-fs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:  
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Oct 04 19:00:21 UTC 2012
>Closed-Date:    
>Last-Modified:  Wed Jun 12 00:20:00 UTC 2013
>Originator:     Garrett Cooper
>Release:        9.0-RELEASE
>Organization:
EMC Isilon
>Environment:
9.0-RELEASE amd64 install media
>Description:
I accidentally got my invocation backwards, was impatient and tried the opposite form and it blew up looking in the VOP code when I did the following:

1. Boot 9.0-RELEASE as a LiveCD.
2. Execute the following commands:
   mkdir /tmp/etc
   mount_unionfs /tmp/etc /etc
   mount_unionfs /etc /tmp/etc
3. Accessing either /etc or /tmp/etc after that should result in a panic.
>How-To-Repeat:

>Fix:


>Release-Note:
>Audit-Trail:
Responsible-Changed-From-To: freebsd-bugs->freebsd-fs 
Responsible-Changed-By: linimon 
Responsible-Changed-When: Fri Oct 5 02:14:13 UTC 2012 
Responsible-Changed-Why:  
Over to maintainer(s). 

http://www.freebsd.org/cgi/query-pr.cgi?pr=172334 

From: Daichi GOTO <daichi@ongs.co.jp>
To: bug-followup@FreeBSD.org,
 yanegomi@gmail.com
Cc:  
Subject: Re: kern/172334: [unionfs] unionfs permits recursive union mounts; causes panic quickly
Date: Thu, 18 Oct 2012 10:17:59 +0200

 You could around this issue with a following patch.
 
   http://people.freebsd.org/~daichi/unionfs/unionfs-cross-mount3.diff
 
 And above patch is rejected at ml discussion some years ago. 
 We need more radical changes to improve this kind of issues.
 
 --
 Daichi GOTO
 81-42-316-7945 | daichi@ongs.co.jp | http://www.ongs.co.jp
 LinkedIn: http://linkedin.com/in/daichigoto
 

From: Garrett Cooper <yaneurabeya@gmail.com>
To: bug-followup@FreeBSD.org, yaneurabeya@gmail.com
Cc: daichi@FreeBSD.org
Subject: Re: kern/172334: [unionfs] unionfs permits recursive union mounts;
 causes panic quickly
Date: Tue, 11 Jun 2013 17:10:20 -0700

 I finally got around to testing this. Yup -- the patch looks good to me.
 Thank you Daichi!
 -Garrett
>Unformatted:
