From owner-freebsd-current  Wed Apr  2 10:44:44 1997
Return-Path: <owner-current>
Received: (from root@localhost)
          by freefall.freebsd.org (8.8.5/8.8.5) id KAA15609
          for current-outgoing; Wed, 2 Apr 1997 10:44:44 -0800 (PST)
Received: from phaeton.artisoft.com (phaeton.Artisoft.COM [198.17.250.50])
          by freefall.freebsd.org (8.8.5/8.8.5) with SMTP id KAA15603;
          Wed, 2 Apr 1997 10:44:38 -0800 (PST)
Received: (from terry@localhost) by phaeton.artisoft.com (8.6.11/8.6.9) id LAA14010; Wed, 2 Apr 1997 11:28:05 -0700
From: Terry Lambert <terry@lambert.org>
Message-Id: <199704021828.LAA14010@phaeton.artisoft.com>
Subject: Re: ufs lock panic in -current
To: ache@nagual.ru (=?KOI8-R?B?4c7E0sXKIP7F0s7P1w==?=)
Date: Wed, 2 Apr 1997 11:28:05 -0700 (MST)
Cc: dyson@FreeBSD.ORG, bde@zeta.org.au, current@FreeBSD.ORG
In-Reply-To: <Pine.BSF.3.96.970402080704.271A-100000@nagual.ru> from "=?KOI8-R?B?4c7E0sXKIP7F0s7P1w==?=" at Apr 2, 97 08:10:30 am
X-Mailer: ELM [version 2.4 PL24]
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: owner-current@FreeBSD.ORG
X-Loop: FreeBSD.org
Precedence: bulk

> I just got following panic:
> 
> lockmgr: locking against myself
> 
> stack looks like:
> 
> lockmgr
> ufs_lock
> vn_lock
> vputrele
> vrele
> vnode_pager_dealloc
> vm_pager_deallocate
> vm_pager_terminate
> vm_object_deallocate
> vputrele
> vrele
> execve
> 
> Please, fix.

The fix is conceptually non-trivial, and requires that the transitive
closure be calculated at the same layer for all FS's.  This implies a
veto, rather than a call-down, interface for VOP_LOCK.

Physically, the fix is about 200 lines of code, including all FS
code changes.


					Regards,
					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.