From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933629AbdKBOoQ (ORCPT ); Thu, 2 Nov 2017 10:44:16 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:34926 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933448AbdKBOoP (ORCPT ); Thu, 2 Nov 2017 10:44:15 -0400 Subject: Re: [Jfs-discussion] [PATCH] jfs: Add missing NULL pointer check in __get_metapage To: Juerg Haefliger , jfs-discussion@lists.sourceforge.net, linux-kernel@vger.kernel.org References: <20171004082441.2405-1-juerg.haefliger@canonical.com> <1dbf4a54-968f-0ca7-da96-e262c653fecb@canonical.com> <778bc3d1-4bf4-ed83-3cc3-19d6efb5cceb@canonical.com> <0c8c1f0e-c3af-308f-aee0-d7b8c14f45d8@oracle.com> <50f61041-7507-6410-ddf5-36892759be8b@canonical.com> From: Dave Kleikamp Message-ID: <30b7320e-3fd4-71b7-3aa4-c62cbf49aa14@oracle.com> Date: Thu, 2 Nov 2017 09:44:03 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <50f61041-7507-6410-ddf5-36892759be8b@canonical.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Source-IP: userv0022.oracle.com [156.151.31.74] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/02/2017 08:43 AM, Juerg Haefliger wrote: >>>> Furthermore, it looks like all the callers of __get_metapage() check for >>>> a null return, so I'm not sure we need to handle the error at this >>>> point. I might have to look a bit harder at that, since there are many >>>> callers. >>> >>> I don't understand this either :-) Yes, the callers do check for a null >>> pointer but things blow up (in __get_metapage) before that check without >>> the above fix. >> >> Yeah, the fix to __get_metapage() is necessary. I'm not convinced the >> first part of the patch, to alloc_metapage(), is necessary. > > It's not. I just thought it'd be nice to get some sort of notification > in the log when the alloc fails. But if the callers log it then that's fine. Okay. I'll push just the __get_metapage part of your patch. Thanks, Shaggy