From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:54108 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752387AbdKXJjm (ORCPT ); Fri, 24 Nov 2017 04:39:42 -0500 Date: Fri, 24 Nov 2017 10:39:46 +0100 From: Greg KH To: Michal Hocko Cc: Jiri Slaby , jaewon31.kim@samsung.com, akpm@linux-foundation.org, js1304@gmail.com, minchan@kernel.org, stable@vger.kernel.org, torvalds@linux-foundation.org, Yang Shi , Arnd Bergmann , Joonsoo Kim , Michal Hocko Subject: Re: [PATCH] mm: check the return value of lookup_page_ext for all call sites Message-ID: <20171124093946.GA13309@kroah.com> References: <20171124092832.esq7pxxfeepok4yt@dhcp22.suse.cz> <20171124093032.32071-1-mhocko@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171124093032.32071-1-mhocko@kernel.org> Sender: stable-owner@vger.kernel.org List-ID: On Fri, Nov 24, 2017 at 10:30:32AM +0100, Michal Hocko wrote: > From: Yang Shi > > commit f86e4271978bd93db466d6a95dad4b0fdcdb04f6 upstream. > > Per the discussion with Joonsoo Kim [1], we need check the return value > of lookup_page_ext() for all call sites since it might return NULL in > some cases, although it is unlikely, i.e. memory hotplug. > > Tested with ltp with "page_owner=0". > > [1] http://lkml.kernel.org/r/20160519002809.GA10245@js1304-P5Q-DELUXE > > [akpm@linux-foundation.org: fix build-breaking typos] > [arnd@arndb.de: fix build problems from lookup_page_ext] > Link: http://lkml.kernel.org/r/6285269.2CksypHdYp@wuerfel > [akpm@linux-foundation.org: coding-style fixes] > Link: http://lkml.kernel.org/r/1464023768-31025-1-git-send-email-yang.shi@linaro.org > Signed-off-by: Yang Shi > Signed-off-by: Arnd Bergmann > Cc: Joonsoo Kim > Signed-off-by: Andrew Morton > Signed-off-by: Linus Torvalds > Signed-off-by: Michal Hocko Can you send a patch on top of 4.4.101 to resolve this instead? thanks, greg k-h