From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2ACE3C433DF for ; Fri, 24 Jul 2020 06:57:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F08D12073E for ; Fri, 24 Jul 2020 06:57:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595573867; bh=adW6TyA/SPwSkxmNhrl3jn0h03AFaHiMV+zf1Zarero=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=Rg7MLGwYSfy+EMB3lkPyxBp3Jm0+7Bkr0Kaq5zfPHxrCr6vH4k02ZvaGTHxW9E6NR 6Cm4xdqjO1Hqyh63+JNL714NlVNg2vsIKTP1v6cFcnju1XEySzJ6UX6ZY0jeOEWlkp Qi9E2bd8HKhYR37/6aiOj15fPU7ic9qwV8Yw9j4Y= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726852AbgGXG5p (ORCPT ); Fri, 24 Jul 2020 02:57:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:44220 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725942AbgGXG5p (ORCPT ); Fri, 24 Jul 2020 02:57:45 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 875D520714; Fri, 24 Jul 2020 06:57:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595573865; bh=adW6TyA/SPwSkxmNhrl3jn0h03AFaHiMV+zf1Zarero=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=aVCxZM/LaH60D7KBxpNKWQmpMxtoN+V+d3hy3Pc+GwgYUa3Rte5cUjjUueQtJ9Z9K HfqYiXKLnfXpxHfWySNj/Kez/LxKxpxF1uxkCoTRSF5nfhc+AQJv264RWPEWzI5txF 2al36PdHWZYTIg61KP+TwjqY4l2HwV8F1nOPevBU= Date: Fri, 24 Jul 2020 08:57:47 +0200 From: Greg KH To: Madhuparna Bhowmik Cc: David Miller , isdn@linux-pingi.de, arnd@arndb.de, edumazet@google.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, andrianov@ispras.ru, ldv-project@linuxtesting.org Subject: Re: [PATCH] drivers: isdn: capi: Fix data-race bug Message-ID: <20200724065747.GF3880088@kroah.com> References: <20200722172329.16727-1-madhuparnabhowmik10@gmail.com> <20200723.151158.2190104866687627036.davem@davemloft.net> <20200724044807.GA474@madhuparna-HP-Notebook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200724044807.GA474@madhuparna-HP-Notebook> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 24, 2020 at 10:18:07AM +0530, Madhuparna Bhowmik wrote: > On Thu, Jul 23, 2020 at 03:11:58PM -0700, David Miller wrote: > > From: madhuparnabhowmik10@gmail.com > > Date: Wed, 22 Jul 2020 22:53:29 +0530 > > > > > From: Madhuparna Bhowmik > > > > > > In capi_init(), after register_chrdev() the file operation callbacks > > > can be called. However capinc_tty_init() is called later. > > > Since capiminors and capinc_tty_driver are initialized in > > > capinc_tty_init(), their initialization can race with their usage > > > in various callbacks like in capi_release(). > > > > > > Therefore, call capinc_tty_init() before register_chrdev to avoid > > > such race conditions. > > > > > > Found by Linux Driver Verification project (linuxtesting.org). > > > > > > Signed-off-by: Madhuparna Bhowmik > > > > I agree with Arnd that this just exchanges one set of problems for > > another. > > Thanks Arnd and David, for reviewing the patch. > Do you have any suggestions on how to fix this correctly? Based on the installed base of ISDN systems, and the fact that no one has ever actually hit this race and reported it ever, I wouldn't worry about it :) thanks, greg k-h