From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.1 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLACK,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ACAA9C433DB for ; Wed, 13 Jan 2021 07:36:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6205D23333 for ; Wed, 13 Jan 2021 07:36:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726506AbhAMHgK (ORCPT ); Wed, 13 Jan 2021 02:36:10 -0500 Received: from mga01.intel.com ([192.55.52.88]:51012 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725773AbhAMHgJ (ORCPT ); Wed, 13 Jan 2021 02:36:09 -0500 IronPort-SDR: 46t7xAEYRZoO9WmE0Lh1UYss4wjTx5MatGrMspAM5k71O7li0mNfvgzjPBUTHAtinMFY9gBicW I0PsQkVxySgQ== X-IronPort-AV: E=McAfee;i="6000,8403,9862"; a="196799236" X-IronPort-AV: E=Sophos;i="5.79,343,1602572400"; d="scan'208";a="196799236" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jan 2021 23:35:28 -0800 IronPort-SDR: TxaCVHWg9sHbgbbnmaJoX83Ad9yllXRKmlOa04N3hMfRvtzA0XjaxcTjtdpq8+VY66nf+DHuVm hoYIkt//vKDw== X-IronPort-AV: E=Sophos;i="5.79,343,1602572400"; d="scan'208";a="397639445" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.25]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jan 2021 23:35:28 -0800 Subject: [PATCH v3 2/6] mm: Teach pfn_to_online_page() to consider subsection validity From: Dan Williams To: linux-mm@kvack.org Cc: Qian Cai , Michal Hocko , Oscar Salvador , David Hildenbrand , vishal.l.verma@intel.com, linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org Date: Tue, 12 Jan 2021 23:35:27 -0800 Message-ID: <161052332755.1805594.9846390935351758277.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <161052331545.1805594.2356512831689786960.stgit@dwillia2-desk3.amr.corp.intel.com> References: <161052331545.1805594.2356512831689786960.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.18-3-g996c MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org pfn_section_valid() determines pfn validity on subsection granularity where pfn_valid() may be limited to coarse section granularity. Explicitly validate subsections after pfn_valid() succeeds. Fixes: b13bc35193d9 ("mm/hotplug: invalid PFNs from pfn_to_online_page()") Cc: Qian Cai Cc: Michal Hocko Cc: Oscar Salvador Reported-by: David Hildenbrand Signed-off-by: Dan Williams --- mm/memory_hotplug.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 55a69d4396e7..9f37f8a68da4 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -308,11 +308,27 @@ static int check_hotplug_memory_addressable(unsigned long pfn, struct page *pfn_to_online_page(unsigned long pfn) { unsigned long nr = pfn_to_section_nr(pfn); + struct mem_section *ms; + + if (nr >= NR_MEM_SECTIONS) + return NULL; + + ms = __nr_to_section(nr); + if (!online_section(ms)) + return NULL; + + /* + * Save some code text when online_section() + + * pfn_section_valid() are sufficient. + */ + if (IS_ENABLED(CONFIG_HAVE_ARCH_PFN_VALID)) + if (!pfn_valid(pfn)) + return NULL; + + if (!pfn_section_valid(ms, pfn)) + return NULL; - if (nr < NR_MEM_SECTIONS && online_section_nr(nr) && - pfn_valid_within(pfn)) - return pfn_to_page(pfn); - return NULL; + return pfn_to_page(pfn); } EXPORT_SYMBOL_GPL(pfn_to_online_page);