From patchwork Tue Aug 29 02:02:13 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Tatashin X-Patchwork-Id: 806904 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 3xhBn85Bk8z9sRm for ; Tue, 29 Aug 2017 12:05:48 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751319AbdH2CDx (ORCPT ); Mon, 28 Aug 2017 22:03:53 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:25865 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751241AbdH2CDu (ORCPT ); Mon, 28 Aug 2017 22:03:50 -0400 Received: from userv0021.oracle.com (userv0021.oracle.com [156.151.31.71]) by aserp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id v7T22XfE011013 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 29 Aug 2017 02:02:34 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userv0021.oracle.com (8.14.4/8.14.4) with ESMTP id v7T22X2G006868 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 29 Aug 2017 02:02:33 GMT Received: from abhmp0011.oracle.com (abhmp0011.oracle.com [141.146.116.17]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id v7T22T9x010241; Tue, 29 Aug 2017 02:02:30 GMT Received: from ca-ldom-ol-build-1.us.oracle.com (/10.129.68.23) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 28 Aug 2017 19:02:29 -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, will.deacon@arm.com, catalin.marinas@arm.com, sam@ravnborg.org, mgorman@techsingularity.net, Steven.Sistare@oracle.com, daniel.m.jordan@oracle.com, bob.picco@oracle.com Subject: [PATCH v7 02/11] sparc64/mm: setting fields in deferred pages Date: Mon, 28 Aug 2017 22:02:13 -0400 Message-Id: <1503972142-289376-3-git-send-email-pasha.tatashin@oracle.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1503972142-289376-1-git-send-email-pasha.tatashin@oracle.com> References: <1503972142-289376-1-git-send-email-pasha.tatashin@oracle.com> X-Source-IP: userv0021.oracle.com [156.151.31.71] 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 --- arch/sparc/mm/init_64.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c index b3020a956b87..12dbba85a2e2 100644 --- a/arch/sparc/mm/init_64.c +++ b/arch/sparc/mm/init_64.c @@ -2508,9 +2508,15 @@ 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.