NetBSD Problem Report #26773

Received: (qmail 20211 invoked by uid 605); 27 Aug 2004 02:17:52 -0000
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Date: Fri, 27 Aug 2004 11:17:42 +0900
From: yamt@mwd.biglobe.ne.jp
Sender: gnats-bugs-owner@NetBSD.org
Reply-To: yamt@mwd.biglobe.ne.jp
To: gnats-bugs@gnats.NetBSD.org
Subject: ipf assumes mbufs are always writable
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>Number:         26773
>Category:       kern
>Synopsis:       ipf assumes mbufs are always writable
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    ipf-bug-people
>State:          analyzed
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Aug 27 02:18:01 +0000 2004
>Closed-Date:    
>Last-Modified:  Tue Sep 05 23:11:32 +0000 2006
>Originator:     YAMAMOTO Takashi <yamt@mwd.biglobe.ne.jp>
>Release:        NetBSD 2.0G
>Organization:

>Environment:


System: NetBSD kaeru 2.0G NetBSD 2.0G (build.kaeru) #1626: Thu Aug 26 21:45:21 JST 2004 takashi@kaeru:/home/takashi/work/kernel/build.kaeru i386
Architecture: i386
Machine: i386
>Description:
	ipf have an assumption that mbufs are always writable.
	it sometimes does m_copyback on a shared mbuf and
	triggers an assertion failure ("mlen == 0 || !M_READONLY(m)")
	in m_copyback.

	while 2-0 branch doesn't have the KASSERT, i think that
	the problem itsself exists on the branch as well.

	PR/26433 is about the same problem of pf.
	PR/25761 also has some related info, including a stack trace.

>How-To-Repeat:
	see PR/25761.

>Fix:
	always ensuring that mbufs are writable beforehand
	(in fr_check_wrapper?) might be a short-term fix.

	for long-term, it's better to do some kind of copy-on-write.
>Release-Note:
>Audit-Trail:

From: YAMAMOTO Takashi <yamt@netbsd.org>
To: gnats-bugs@gnats.NetBSD.org
Cc:  
Subject: pr/26773 CVS commit: src/sys/netinet
Date: Mon,  6 Sep 2004 10:00:43 +0000 (UTC)

 Module Name:	src
 Committed By:	yamt
 Date:		Mon Sep  6 10:00:43 UTC 2004

 Modified Files:
 	src/sys/netinet: ip_fil_netbsd.c

 Log Message:
 fr_check_wrapper, fr_check_wrapper6:
 ensure that mbufs are writable beforehand as ipf assumes.
 PR/26773 and PR/26850.


 To generate a diff of this commit:
 cvs rdiff -r1.14 -r1.15 src/sys/netinet/ip_fil_netbsd.c

 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.


From: Havard Eidnes <he@netbsd.org>
To: gnats-bugs@gnats.NetBSD.org
Cc:  
Subject: pr/26773 CVS commit: [netbsd-2-0] src/sys/netinet
Date: Sat, 11 Sep 2004 11:23:27 +0000 (UTC)

 Module Name:	src
 Committed By:	he
 Date:		Sat Sep 11 11:23:27 UTC 2004

 Modified Files:
 	src/sys/netinet [netbsd-2-0]: ip_fil_netbsd.c

 Log Message:
 Pull up revision 1.15 (requested by yamt in ticket #833):
   Ensure that mbufs are writable, as IPF assumes so.
   Fixes PR#26773 and PR#26850.


 To generate a diff of this commit:
 cvs rdiff -r1.3.2.8 -r1.3.2.9 src/sys/netinet/ip_fil_netbsd.c

 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.

State-Changed-From-To: open->feedback 
State-Changed-By: jdolecek 
State-Changed-When: Sun Oct 3 11:16:16 UTC 2004 
State-Changed-Why:  
Is this fixed by your commit? If yes, please close this PR. 
State-Changed-From-To: feedback->analyzed 
State-Changed-By: yamt 
State-Changed-When: Sun Oct 3 22:29:49 UTC 2004 
State-Changed-Why:  
workarounded. 
Responsible-Changed-From-To: kern-bug-people->darrenr
Responsible-Changed-By: darrenr@netbsd.org
Responsible-Changed-When: Thu, 08 Dec 2005 11:12:29 +0000
Responsible-Changed-Why:


From: darrenr@netbsd.org (Darren Reed)
To: yamt@mwd.biglobe.ne.jp
Cc: gnats-bugs@netbsd.org
Subject: Re: kern/26773
Date: Thu,  8 Dec 2005 11:12:10 +0000 (UTC)

 You've commented that the current situation is "workarounded".

 What would you consider the correct fix?

From: YAMAMOTO Takashi <yamt@mwd.biglobe.ne.jp>
To: darrenr@netbsd.org
Cc: gnats-bugs@netbsd.org
Subject: Re: kern/26773
Date: Thu, 08 Dec 2005 21:16:06 +0900

 > You've commented that the current situation is "workarounded".
 > 
 > What would you consider the correct fix?

 mbufs should be copied only when being modified, rather than always.

 YAMAMOTO Takashi

Responsible-Changed-From-To: darrenr->kern-bug-people
Responsible-Changed-By: wiz@netbsd.org
Responsible-Changed-When: Sun, 03 Sep 2006 01:06:40 +0000
Responsible-Changed-Why:
Back to role account, darrenr doesn't have commit access any longer.


Responsible-Changed-From-To: kern-bug-people->ipf-bug-people
Responsible-Changed-By: wiz@netbsd.org
Responsible-Changed-When: Tue, 05 Sep 2006 23:11:32 +0000
Responsible-Changed-Why:
New role account for IPF bugs.


>Unformatted:

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