From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751331AbbLHWRj (ORCPT ); Tue, 8 Dec 2015 17:17:39 -0500 Received: from lxorguk.ukuu.org.uk ([81.2.110.251]:40168 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750769AbbLHWRi (ORCPT ); Tue, 8 Dec 2015 17:17:38 -0500 Date: Tue, 8 Dec 2015 22:16:57 +0000 From: One Thousand Gnomes To: Paul Bolle Cc: Tilman Schmidt , netdev@vger.kernel.org, Peter Hurley , Sasha Levin , syzkaller@googlegroups.com, David Miller , Karsten Keil , isdn4linux@listserv.isdn4linux.de, gigaset307x-common@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/3] ser_gigaset: fix up NULL checks Message-ID: <20151208221657.71fd0d71@lxorguk.ukuu.org.uk> In-Reply-To: <1449603913.2384.16.camel@tiscali.nl> References: <1449603913.2384.16.camel@tiscali.nl> Organization: Intel Corporation X-Mailer: Claws Mail 3.12.0 (GTK+ 2.24.28; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Should we backport this all the way to v2.6.32 (currently the oldest > stable tree)? We need to be able to explain how the case being tested can occur, then explain the situation in which it actually prevents a race condition. If nobody can do that then it shouldn't be backported because its change without value and just risk. The right fix as far as I can see is to remove the tests although WARN_ON() combined with your tty->ops change might be safer. > It's pretty obvious that this should have been part of commit > f34d7a5b7010 ("tty: The big operations rework"). That being said, these It ahould probably have been fixed around the same time or in one of the tty locking reviews, but drivers/isdn and net/irda weren't traditionally part of the general tty maintenance but handled separately/ > test puzzle me. It's not obvious why they're needed. Ie, can the null > dereferences they try to catch really happen? But I can try to figure > out that in the future, if I ever feel the urge to do so. Anyhow: > > Acked-by: Paul Bolle Nacked-by: Alan Cox