Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751444AbdILU6k (ORCPT ); Tue, 12 Sep 2017 16:58:40 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:33488 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750869AbdILU6h (ORCPT ); Tue, 12 Sep 2017 16:58:37 -0400 Date: Tue, 12 Sep 2017 13:58:35 -0700 From: Andrew Morton To: Alexandru Moise <00moses.alexander00@gmail.com>, linux-kernel@vger.kernel.org, khandual@linux.vnet.ibm.com, mhocko@suse.com, aarcange@redhat.com, minchan@kernel.org, hillf.zj@alibaba-inc.com, shli@fb.com, rppt@linux.vnet.ibm.com, kirill.shutemov@linux.intel.com, mgorman@techsingularity.net, rientjes@google.com, riel@redhat.com, linux-mm@kvack.org, Naoya Horiguchi Subject: Re: [PATCH] mm, hugetlb, soft_offline: save compound page order before page migration Message-Id: <20170912135835.0b48340ead5570e50529f676@linux-foundation.org> In-Reply-To: <20170912135448.341359676c6f8045f4a622f0@linux-foundation.org> References: <20170912204306.GA12053@gmail.com> <20170912135448.341359676c6f8045f4a622f0@linux-foundation.org> X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 643 Lines: 14 On Tue, 12 Sep 2017 13:54:48 -0700 Andrew Morton wrote: > On Tue, 12 Sep 2017 22:43:06 +0200 Alexandru Moise <00moses.alexander00@gmail.com> wrote: > > > This fixes a bug in madvise() where if you'd try to soft offline a > > hugepage via madvise(), while walking the address range you'd end up, > > using the wrong page offset due to attempting to get the compound > > order of a former but presently not compound page, due to dissolving > > the huge page (since c3114a8). > > What are the user visible effects of the bug? The wrong page is > offlined? No offlining occurs? This also affects MADV_HWPOISON?