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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_NEOMUTT autolearn=ham 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 325C0C4321D for ; Wed, 22 Aug 2018 06:41:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DF6832148E for ; Wed, 22 Aug 2018 06:41:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DF6832148E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728094AbeHVKFI (ORCPT ); Wed, 22 Aug 2018 06:05:08 -0400 Received: from metis.ext.pengutronix.de ([85.220.165.71]:42001 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726983AbeHVKFI (ORCPT ); Wed, 22 Aug 2018 06:05:08 -0400 Received: from pty.hi.pengutronix.de ([2001:67c:670:100:1d::c5]) by metis.ext.pengutronix.de with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1fsMph-0006pY-D9; Wed, 22 Aug 2018 08:41:33 +0200 Received: from ukl by pty.hi.pengutronix.de with local (Exim 4.89) (envelope-from ) id 1fsMpf-0000vn-52; Wed, 22 Aug 2018 08:41:31 +0200 Date: Wed, 22 Aug 2018 08:41:31 +0200 From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= To: Anton Vasilyev Cc: Greg Kroah-Hartman , Jiri Slaby , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, ldv-project@linuxtesting.org Subject: Re: [PATCH v2] serial: mxs-auart: Fix potential infinite loop Message-ID: <20180822064131.2qy3ntri7rdypmfo@pengutronix.de> References: <20180806164346.9986-1-vasilyev@ispras.ru> <20180807105905.18264-1-vasilyev@ispras.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20180807105905.18264-1-vasilyev@ispras.ru> User-Agent: NeoMutt/20170113 (1.7.2) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c5 X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 07, 2018 at 01:59:05PM +0300, Anton Vasilyev wrote: > On the error path of mxs_auart_request_gpio_irq() is performed > backward iterating with index i of enum type. Underline enum type > may be unsigned char. In this case check (--i >= 0) will be always > true and error handling goes into infinite loop. > > The patch changes the check so that it is valid for signed and unsigned > types. > > Found by Linux Driver Verification project (linuxtesting.org). > > Signed-off-by: Anton Vasilyev > --- > v2: mistype in patch as result of combination of different fixes. > Change comment and leave enum type. > --- > drivers/tty/serial/mxs-auart.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c > index 76aa289652f7..27235a526cce 100644 > --- a/drivers/tty/serial/mxs-auart.c > +++ b/drivers/tty/serial/mxs-auart.c > @@ -1634,8 +1634,9 @@ static int mxs_auart_request_gpio_irq(struct mxs_auart_port *s) > > /* > * If something went wrong, rollback. > + * Be careful: i may be unsigned. > */ > - while (err && (--i >= 0)) > + while (err && (i-- > 0)) > if (irq[i] >= 0) > free_irq(irq[i], s); I wouldn't have added the comment, but the code change is correct. Acked-by: Uwe Kleine-König Thanks Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |