From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756227AbdJJMrj (ORCPT ); Tue, 10 Oct 2017 08:47:39 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:19002 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755144AbdJJMri (ORCPT ); Tue, 10 Oct 2017 08:47:38 -0400 Subject: Re: [PATCH review for 4.9 31/50] xen/manage: correct return value check on xenbus_scanf() To: "Levin, Alexander (Sasha Levin)" , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" References: <20171007223636.24797-1-alexander.levin@verizon.com> <20171007223636.24797-31-alexander.levin@verizon.com> Cc: Jan Beulich From: Boris Ostrovsky Message-ID: <0c5dfb50-0dc4-7df5-ae5c-1998781289dd@oracle.com> Date: Tue, 10 Oct 2017 08:49:13 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <20171007223636.24797-31-alexander.levin@verizon.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Source-IP: aserv0021.oracle.com [141.146.126.233] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/07/2017 06:36 PM, Levin, Alexander (Sasha Levin) wrote: > From: Jan Beulich > > [ Upstream commit 4fed1b125eb6252bde478665fc05d4819f774fa8 ] > > A negative return value indicates an error; in fact the function at > present won't ever return zero. > > Signed-off-by: Jan Beulich > Reviewed-by: Juergen Gross > Signed-off-by: Boris Ostrovsky > Signed-off-by: Sasha Levin This patch will cause a warning to be printed. Please pull commit 4e93b64 ("xen: don't print error message in case of missing Xenstore entry") as well. Thanks. -boris > --- > drivers/xen/manage.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c > index 26e5e8507f03..357a8db859c9 100644 > --- a/drivers/xen/manage.c > +++ b/drivers/xen/manage.c > @@ -277,7 +277,7 @@ static void sysrq_handler(struct xenbus_watch *watch, const char **vec, > err = xenbus_transaction_start(&xbt); > if (err) > return; > - if (!xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key)) { > + if (xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key) < 0) { > pr_err("Unable to read sysrq code in control/sysrq\n"); > xenbus_transaction_end(xbt, 1); > return;