From patchwork Fri Oct 13 17:32:06 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Tatashin X-Patchwork-Id: 825631 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=sparclinux-owner@vger.kernel.org; receiver=) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3yDFF20BcMz9sRV for ; Sat, 14 Oct 2017 04:33:42 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752773AbdJMRdk (ORCPT ); Fri, 13 Oct 2017 13:33:40 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:39379 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750973AbdJMRdj (ORCPT ); Fri, 13 Oct 2017 13:33:39 -0400 Received: from aserv0022.oracle.com (aserv0022.oracle.com [141.146.126.234]) by userp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id v9DHWQoe020093 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 13 Oct 2017 17:32:27 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserv0022.oracle.com (8.14.4/8.14.4) with ESMTP id v9DHWPMI028237 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 13 Oct 2017 17:32:26 GMT Received: from abhmp0017.oracle.com (abhmp0017.oracle.com [141.146.116.23]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id v9DHWOum024020; Fri, 13 Oct 2017 17:32:24 GMT Received: from localhost.localdomain (/98.216.35.41) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 13 Oct 2017 10:32:24 -0700 From: Pavel Tatashin To: linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-arm-kernel@lists.infradead.org, x86@kernel.org, kasan-dev@googlegroups.com, borntraeger@de.ibm.com, heiko.carstens@de.ibm.com, davem@davemloft.net, willy@infradead.org, mhocko@kernel.org, ard.biesheuvel@linaro.org, mark.rutland@arm.com, will.deacon@arm.com, catalin.marinas@arm.com, sam@ravnborg.org, mgorman@techsingularity.net, akpm@linux-foundation.org, steven.sistare@oracle.com, daniel.m.jordan@oracle.com, bob.picco@oracle.com Subject: [PATCH v12 03/11] sparc64/mm: setting fields in deferred pages Date: Fri, 13 Oct 2017 13:32:06 -0400 Message-Id: <20171013173214.27300-4-pasha.tatashin@oracle.com> X-Mailer: git-send-email 2.14.2 In-Reply-To: <20171013173214.27300-1-pasha.tatashin@oracle.com> References: <20171013173214.27300-1-pasha.tatashin@oracle.com> X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: sparclinux-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: sparclinux@vger.kernel.org Without deferred struct page feature (CONFIG_DEFERRED_STRUCT_PAGE_INIT), flags and other fields in "struct page"es are never changed prior to first initializing struct pages by going through __init_single_page(). With deferred struct page feature enabled there is a case where we set some fields prior to initializing: mem_init() { register_page_bootmem_info(); free_all_bootmem(); ... } When register_page_bootmem_info() is called only non-deferred struct pages are initialized. But, this function goes through some reserved pages which might be part of the deferred, and thus are not yet initialized. mem_init register_page_bootmem_info register_page_bootmem_info_node get_page_bootmem .. setting fields here .. such as: page->freelist = (void *)type; free_all_bootmem() free_low_memory_core_early() for_each_reserved_mem_region() reserve_bootmem_region() init_reserved_page() <- Only if this is deferred reserved page __init_single_pfn() __init_single_page() memset(0) <-- Loose the set fields here We end-up with similar issue as in the previous patch, where currently we do not observe problem as memory is zeroed. But, if flag asserts are changed we can start hitting issues. Also, because in this patch series we will stop zeroing struct page memory during allocation, we must make sure that struct pages are properly initialized prior to using them. The deferred-reserved pages are initialized in free_all_bootmem(). Therefore, the fix is to switch the above calls. Signed-off-by: Pavel Tatashin Reviewed-by: Steven Sistare Reviewed-by: Daniel Jordan Reviewed-by: Bob Picco Acked-by: David S. Miller Acked-by: Michal Hocko --- arch/sparc/mm/init_64.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c index 6034569e2c0d..caed495544e9 100644 --- a/arch/sparc/mm/init_64.c +++ b/arch/sparc/mm/init_64.c @@ -2548,9 +2548,16 @@ void __init mem_init(void) { high_memory = __va(last_valid_pfn << PAGE_SHIFT); - register_page_bootmem_info(); free_all_bootmem(); + /* + * Must be done after boot memory is put on freelist, because here we + * might set fields in deferred struct pages that have not yet been + * initialized, and free_all_bootmem() initializes all the reserved + * deferred pages for us. + */ + register_page_bootmem_info(); + /* * Set up the zero page, mark it reserved, so that page count * is not manipulated when freeing the page from user ptes.