Received:  by oss.sgi.com id <S42349AbQFUDLX>;
	Tue, 20 Jun 2000 20:11:23 -0700
Received: from host.dsl.speakeasy.net ([216.254.93.178]:19703 "EHLO
        vaio.greennet") by oss.sgi.com with ESMTP id <S42311AbQFUDLR>;
	Tue, 20 Jun 2000 20:11:17 -0700
Received: from localhost (becker@localhost)
	by vaio.greennet (8.9.3/8.8.7) with ESMTP id XAA00738;
	Tue, 20 Jun 2000 23:12:36 -0400
Date:   Tue, 20 Jun 2000 23:12:36 -0400 (EDT)
From:   Donald Becker <becker@scyld.com>
X-Sender: becker@vaio.greennet
To:     Andrew Morton <andrewm@uow.edu.au>
cc:     "netdev@oss.sgi.com" <netdev@oss.sgi.com>
Subject: Re: modular net drivers, take 2
In-Reply-To: <395017F3.516165AD@uow.edu.au>
Message-ID: <Pine.LNX.4.10.10006202140210.26261-100000@vaio.greennet>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Sender: owner-netdev@oss.sgi.com
Precedence: bulk
Return-Path: <owner-netdev@oss.sgi.com>
X-Orcpt: rfc822;netdev-outgoing

On Wed, 21 Jun 2000, Andrew Morton wrote:

> In this example, both dev->ioctl() and dev->get_stats() are called while
> the module refcount is zero.   So they're as risky as open(); these code
> paths need to be audited for races wrt kmalloc->schedule()
> opportunities.

Hmmm, now this is an important point.

I just "know" that ioctl() and get_stats() should be "simple" functions that
shouldn't do call any kernel function, except for perhaps printk().  This is
not documented in the skeleton driver, or elsewhere.

I'm guessing that the documentation should advise locking the module if any
operation is done in get_stats() or private_ioctl() that might result in a
reschedule.

Donald Becker				becker@scyld.com
Scyld Computing Corporation		http://www.scyld.com
410 Severn Ave. Suite 210		Annapolis MD 21403