From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751233AbcLEGay (ORCPT ); Mon, 5 Dec 2016 01:30:54 -0500 Received: from mx2.suse.de ([195.135.220.15]:55799 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750951AbcLEGax (ORCPT ); Mon, 5 Dec 2016 01:30:53 -0500 Subject: Re: [PATCH 1/1] xen: xenbus: set error code on failure To: Pan Bian , Boris Ostrovsky , David Vrabel , xen-devel@lists.xenproject.org References: <1480762166-4883-1-git-send-email-bianpan2016@163.com> Cc: linux-kernel@vger.kernel.org From: Juergen Gross Message-ID: Date: Mon, 5 Dec 2016 07:30:49 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <1480762166-4883-1-git-send-email-bianpan2016@163.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/12/16 11:49, Pan Bian wrote: > In function xenstored_local_init(), the value of return variable err > should be negative on errors. But the value of err keeps 0 even if the > call to get_zeroed_page() returns a NULL pointer. This patch assigns > "-ENOMEM" to err on the error branch. > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=188721 > > Signed-off-by: Pan Bian > --- > drivers/xen/xenbus/xenbus_probe.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c > index 33a31cf..f87d047 100644 > --- a/drivers/xen/xenbus/xenbus_probe.c > +++ b/drivers/xen/xenbus/xenbus_probe.c > @@ -708,8 +708,10 @@ static int __init xenstored_local_init(void) > > /* Allocate Xenstore page */ > page = get_zeroed_page(GFP_KERNEL); > - if (!page) > + if (!page) { > + err = -ENOMEM; > goto out_err; > + } > > xen_store_gfn = xen_start_info->store_mfn = virt_to_gfn((void *)page); Why don't you preset err to -ENOMEM instead? Initializing it to 0 is kind of pointless. Ans while at it: preinitializing page isn't needed, too, and in the error path testing page for being non-zero isn't neede either (free_page() will do the right thing in case the parameter is 0). Juergen