From owner-freebsd-net@FreeBSD.ORG  Wed Jun  7 17:20:55 2006
Return-Path: <owner-freebsd-net@FreeBSD.ORG>
X-Original-To: freebsd-net@freebsd.org
Delivered-To: freebsd-net@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id E63F916A675;
	Wed,  7 Jun 2006 14:47:28 +0000 (UTC) (envelope-from sem@freebsd.org)
Received: from relay1.beelinegprs.ru (relay1.beelinegprs.ru [217.118.71.5])
	by mx1.FreeBSD.org (Postfix) with ESMTP id 8E4E243D48;
	Wed,  7 Jun 2006 14:47:28 +0000 (GMT) (envelope-from sem@freebsd.org)
Received: from relay1 (localhost [127.0.0.1]) by relay1 (Postfix) with SMTP
	id BDD7A36D30; Wed,  7 Jun 2006 18:44:13 +0400 (MSD)
Received: from [172.19.248.43] (clusterfw.beelinegprs.net [217.118.66.232])
	by relay1.beelinegprs.ru (Postfix) with ESMTP
	id 2C97636D2B; Wed,  7 Jun 2006 18:44:10 +0400 (MSD)
Message-ID: <4486E632.3080204@FreeBSD.org>
Date: Wed, 07 Jun 2006 18:44:02 +0400
From: Sergey Matveychuk <sem@FreeBSD.org>
User-Agent: Thunderbird 1.5.0.2 (X11/20060429)
MIME-Version: 1.0
To: Andrew Thompson <thompsa@freebsd.org>
References: <20060606232543.GB14303@heff.fud.org.nz>
In-Reply-To: <20060606232543.GB14303@heff.fud.org.nz>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
X-Spamtest-Info: License expired
Cc: freebsd-net@freebsd.org
Subject: Re: Sleeping in USB network drivers
X-BeenThere: freebsd-net@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Networking and TCP/IP with FreeBSD <freebsd-net.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-net>,
	<mailto:freebsd-net-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-net>
List-Post: <mailto:freebsd-net@freebsd.org>
List-Help: <mailto:freebsd-net-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-net>,
	<mailto:freebsd-net-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 07 Jun 2006 17:21:00 -0000

Andrew Thompson wrote:
> Hi,
> 
> 
> I am looking into the reported panics with the if_aue driver and have
> come across a locking problem with usb adapters that is not obvious how
> to fix.
> 
> The problem is that usbd_do_request() may sleep and most drivers are
> careful to call it without any locks held. in_addmulti() will grab
> in_multi_mtx before calling if_addmulti() to update the cards multicast
> hash, this effectively means that the driver can not sleep in
> *_setmulti but this is unavoidable with USB.
> 
> Does anyone have any suggestions? (panic and bt below)

It was discussed in usb@. Shortly, USB stack should be rewritten.
The patch can be found at
http://www.turbocat.net/~hselasky/usb4bsd/index.html

-- 
Dixi.
Sem.