From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753262Ab3KZDPq (ORCPT ); Mon, 25 Nov 2013 22:15:46 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:58350 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751616Ab3KZDPo (ORCPT ); Mon, 25 Nov 2013 22:15:44 -0500 Date: Mon, 25 Nov 2013 19:16:29 -0800 From: Greg KH To: channing Cc: linux-kernel@vger.kernel.org, fengguang.wu@intel.com Subject: Re: [PATCH V2] n_gsm: race between ld close and gsmtty open Message-ID: <20131126031629.GA16763@kroah.com> References: <1385435645.7741.28.camel@bichao> <20131126025432.GA3379@kroah.com> <1385436914.7741.40.camel@bichao> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1385436914.7741.40.camel@bichao> User-Agent: Mutt/1.5.22 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 26, 2013 at 11:35:14AM +0800, channing wrote: > On Mon, 2013-11-25 at 18:54 -0800, Greg KH wrote: > > On Tue, Nov 26, 2013 at 11:14:05AM +0800, channing wrote: > > > > This patch is try to avoid it by: > > > > > > 1) in n_gsm driver, use a global gsm mutex lock to avoid gsm_dlci_release() run in > > > parallel with gsmtty_install(); > The commit is updated here than formal patch set: we use mutex lock in > patch V2, while use spin lock in patch V1. > > > > > > > 2) Increase dlci's ref count in gsmtty_install() instead of in gsmtty_open(), the > > > purpose is to prevent gsm_dlci_release() releasing dlci after gsmtty_install() > > > allocats dlci but before gsmtty_open increases dlci's ref count; > > > > > > 3) Decrease dlci's ref count in gsmtty_remove(), a tty framework API, this is the > > > opposite process of step 2). > > > > > > Signed-off-by: Chao Bi > > > Signed-off-by: Greg Kroah-Hartman > > > > I have not signed off on this additional patch. > > > > What is different from the previous version? That information needs to > > be somewhere, otherwise I'm just going to guess and say this is the same > > as your last one, which was incorrect. > The difference with previous one is to use a mutex instead of spin lock > to avoid race, purpose is to avoid sleep in atomic context. I've also > updated commit a little as above. Then be explicit as to what has changed somewhere. We deal with thousands of patches a week, we can not know that you changed one sentance in a patch description of a few hundred lines long to know you made a change to the patch itself as well... thanks, greg k-h