From owner-freebsd-current@FreeBSD.ORG  Wed Apr  2 12:39:31 2003
Return-Path: <owner-freebsd-current@FreeBSD.ORG>
Delivered-To: freebsd-current@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id 5F15A37B401
	for <current@freebsd.org>; Wed,  2 Apr 2003 12:39:31 -0800 (PST)
Received: from rootlabs.com (root.org [67.118.192.226])
	by mx1.FreeBSD.org (Postfix) with SMTP id 7078443FE0
	for <current@freebsd.org>; Wed,  2 Apr 2003 12:39:30 -0800 (PST)
	(envelope-from nate@rootlabs.com)
Received: (qmail 12243 invoked by uid 1000); 2 Apr 2003 20:39:30 -0000
Date: Wed, 2 Apr 2003 12:39:30 -0800 (PST)
From: Nate Lawson <nate@root.org>
To: current@freebsd.org
Message-ID: <Pine.BSF.4.21.0304021235150.12236-100000@root.org>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Subject: mbuf LOR
X-BeenThere: freebsd-current@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: Discussions about the use of FreeBSD-current
	<freebsd-current.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
	<mailto:freebsd-current-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-current>
List-Post: <mailto:freebsd-current@freebsd.org>
List-Help: <mailto:freebsd-current-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
	<mailto:freebsd-current-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 02 Apr 2003 20:39:31 -0000

I was testing some changes to make fxp MPSAFE and got a LOR in allocating
the mbuf cluster and then finally a panic when trying to dereference the
cluster header.  Is the mbuf system MPSAFE?  Is it ok to call m_getcl
with a device lock held (but not Giant)?

The lock reversal was: 1. fxp softc lock, 2. Giant.

Traceback:
zalloc...
malloc()
mb_pop_cont()
mb_alloc()
m_getcl()
fxp_add_rfabuf()
fxp_intr_body()
fxp_intr() -- locks fxp softc

-Nate