From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932698AbVLHXB6 (ORCPT ); Thu, 8 Dec 2005 18:01:58 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932699AbVLHXB6 (ORCPT ); Thu, 8 Dec 2005 18:01:58 -0500 Received: from wproxy.gmail.com ([64.233.184.192]:46782 "EHLO wproxy.gmail.com") by vger.kernel.org with ESMTP id S932698AbVLHXBz convert rfc822-to-8bit (ORCPT ); Thu, 8 Dec 2005 18:01:55 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=lMd5Qs4Bngw67FKNIWwg/llbM6+M7Lysf1rBbSKqVj31KMNXiDN1dD5sE9Uy90gBRrjmNF6Y6AbQUY2PxfmniWmyix27arXrKL7ClGHfG6klbHVK5K182vTODP6ylK0JdL/PSBWwQHa9YbsHfRgpjXlCO4sLViNY/ySc3Y/B9LI= Message-ID: Date: Thu, 8 Dec 2005 18:01:54 -0500 From: Dmitry Torokhov Reply-To: dtor_core@ameritech.net To: Greg KH Subject: Re: Driver bind/unbind and __devinit Cc: LKML In-Reply-To: <20051208222618.GA26295@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Content-Disposition: inline References: <20051208215522.GA25925@suse.de> <20051208222618.GA26295@suse.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On 12/8/05, Greg KH wrote: > On Thu, Dec 08, 2005 at 05:22:12PM -0500, Dmitry Torokhov wrote: > > On 12/8/05, Greg KH wrote: > > > On Thu, Dec 08, 2005 at 04:14:58PM -0500, Dmitry Torokhov wrote: > > > > Hi, > > > > > > > > Many drivers have their probe routines declared as __devinit which is > > > > a no-op unless CONFIG_HOTPLUG is set. However driver's bind/unbind > > > > attributes are created unconditionally, as fas as I can see. Would not > > > > it cause an oops if someone tries to use these attributes with > > > > CONFIG_HOTPLUG=N? Am I missing something? > > > > > > You are missing the CONFIG_HOTPLUG checks around the functions that add > > > and check the device ids from these sysfs files. If CONFIG_HOTPLUG is > > > not enabled, those files do not do anything. > > > > > > > I am slow today... I don't see any dependencies on CONFIG_HOTPLUG in > > drivers/base... Or you talking about one particular subsystem that > > handles this correctly? > > Ugh, very sorry about that, I was thinking of the USB and PCI new_id > stuff. You are right. > > Yes, bind happening after the __init data section is thrown away, if > CONFIG_HOTPLUG is not enabled would be a bad thing. But unbind can > stay. I'll go make up a patch for that. > Unbind may invoke ->remove code which is __devexit[_p] and may be also discarded if !MODULE && !HOTPLUG. > > > > Also, unbind implementation does not seem safe - we check the driver > > > > before taking device's semaphore so we risk unbinding wrong driver (in > > > > the unlikely event that we manage to unbind and bind another driver in > > > > another thread). > > > > > > Do you have a suggestion as to how to fix this? > > > > > > > I think we could take the semaphore before checking driver and then > > use __device_release_driver(). But we'd need to make it global or move > > bind/unbind code into drivers/base/dd.c > > I don't have a problem moving the code if it makes it easier. Have a > patch? :) > Just handwaving for now ;) -- Dmitry