From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f197.google.com (mail-qk0-f197.google.com [209.85.220.197]) by kanga.kvack.org (Postfix) with ESMTP id C54A46B026B for ; Wed, 11 Jul 2018 06:49:48 -0400 (EDT) Received: by mail-qk0-f197.google.com with SMTP id b185-v6so30689121qkg.19 for ; Wed, 11 Jul 2018 03:49:48 -0700 (PDT) Received: from mx1.redhat.com (mx3-rdu2.redhat.com. [66.187.233.73]) by mx.google.com with ESMTPS id j23-v6si18580514qtj.7.2018.07.11.03.49.48 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 11 Jul 2018 03:49:48 -0700 (PDT) Date: Wed, 11 Jul 2018 18:49:44 +0800 From: Baoquan He Subject: Re: Bug report about KASLR and ZONE_MOVABLE Message-ID: <20180711104944.GG1969@MiWiFi-R3L-srv> References: <20180711094244.GA2019@localhost.localdomain> <20180711104158.GE2070@MiWiFi-R3L-srv> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180711104158.GE2070@MiWiFi-R3L-srv> Sender: owner-linux-mm@kvack.org List-ID: To: Chao Fan , akpm@linux-foundation.org, linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, x86@kernel.org, yasu.isimatu@gmail.com, keescook@chromium.org, indou.takao@jp.fujitsu.com, caoj.fnst@cn.fujitsu.com, douly.fnst@cn.fujitsu.com, mhocko@suse.com, vbabka@suse.cz, mgorman@techsingularity.net On 07/11/18 at 06:41pm, Baoquan He wrote: > Hmm, it's an issue, worth fixing it. Otherwise the size of > movable area will be smaller than we expect when add "kernel_core=" > or "movable_core=". > > Add a check in find_zone_movable_pfns_for_nodes(), and use min() to get > the starting address of movable area between aligned '_etext' > and start_pfn. It will go to label 'restart' to calculate the 2nd round > if not satisfiled. > > Hi Chao, > > Could you check if below patch works for you? > > > From ab6e47c6a78d1a4ccb577b995b7b386f3149732f Mon Sep 17 00:00:00 2001 > From: Baoquan He > Date: Wed, 11 Jul 2018 18:30:04 +0800 > Subject: [PATCH] mm, page_alloc: find movable zone after kernel text > > In find_zone_movable_pfns_for_nodes(), when try to find the starting > PFN movable zone begins in each node, kernel text position is not > considered. KASLR may put kernel after which movable zone begins. > > Fix it by finding movable zone after kernel text. > > Signed-off-by: Baoquan He > --- > mm/page_alloc.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 1521100..fe346b4 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -6678,6 +6678,8 @@ static void __init find_zone_movable_pfns_for_nodes(void) > unsigned long size_pages; > > start_pfn = max(start_pfn, zone_movable_pfn[nid]); > + /* KASLR may put kernel after 'start_pfn', start after kernel */ > + start_pfn = max(start_pfn, PAGE_ALIGN(_etext)); Sorry, I used wrong function. Please try this one: