From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932954AbcIEJyU (ORCPT ); Mon, 5 Sep 2016 05:54:20 -0400 Received: from mail.ispras.ru ([83.149.199.45]:60616 "EHLO mail.ispras.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932669AbcIEJyO (ORCPT ); Mon, 5 Sep 2016 05:54:14 -0400 Subject: Re: A potential race in drivers/staging/speakup/speakup.ko To: Samuel Thibault , William Hubbs , Chris Brannon , Kirk Reiser , speakup@linux-speakup.org, devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org, Vaishali Thakkar , ldv-project@linuxtesting.org References: <2b13ceb6-9494-7bec-d0e5-8033c66a8721@ispras.ru> <20160905094317.GB15376@var.bordeaux.inria.fr> From: Pavel Andrianov Message-ID: <58cca2ca-e73c-b7ae-9da9-36be6084caf4@ispras.ru> Date: Mon, 5 Sep 2016 12:54:10 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <20160905094317.GB15376@var.bordeaux.inria.fr> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 05.09.2016 12:43, Samuel Thibault пишет: > Hello, > > Pavel Andrianov, on Mon 05 Sep 2016 11:51:50 +0300, wrote: >> There is a potential race in drivers/staging/speakup/speakup.ko. >> All operations with global pointers buff_in and buff_out are performed >> without any locks. Thus, a simultaneous write (via synth_buffer_clear or >> synth_buffer_add) to the pointers may lead to inconsistent data. >> >> Should a local lock be used here? > > AIUI, all callers of these functions have speakup_info.spinlock held. > > Samuel > Regard a call stack -> synth_direct_store -> synth_printf -> synth_buffer_add The functions have not held speakup_info.spinlock. -- Pavel Andrianov Linux Verification Center, ISPRAS web: http://linuxtesting.org e-mail: andrianov@ispras.ru