From patchwork Mon Mar 29 22:25:54 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sergei Trofimovich X-Patchwork-Id: 411250 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham 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 F13B1C433F1 for ; Mon, 29 Mar 2021 22:28:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CB7ED6024A for ; Mon, 29 Mar 2021 22:28:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232910AbhC2W2W (ORCPT ); Mon, 29 Mar 2021 18:28:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35442 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232981AbhC2W0L (ORCPT ); Mon, 29 Mar 2021 18:26:11 -0400 Received: from smtp.gentoo.org (mail.gentoo.org [IPv6:2001:470:ea4a:1:5054:ff:fec7:86e4]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5D3A7C061762; Mon, 29 Mar 2021 15:26:10 -0700 (PDT) Received: by sf.home (Postfix, from userid 1000) id E848C5A22061; Mon, 29 Mar 2021 23:26:04 +0100 (BST) From: Sergei Trofimovich To: Vlastimil Babka , Andrew Morton , David Hildenbrand , Andrey Konovalov Cc: linux-kernel@vger.kernel.org, Sergei Trofimovich , stable@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH v3] mm: page_alloc: ignore init_on_free=1 for debug_pagealloc=1 Date: Mon, 29 Mar 2021 23:25:54 +0100 Message-Id: <20210329222555.3077928-1-slyfox@gentoo.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On !ARCH_SUPPORTS_DEBUG_PAGEALLOC (like ia64) debug_pagealloc=1 implies page_poison=on: if (page_poisoning_enabled() || (!IS_ENABLED(CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC) && debug_pagealloc_enabled())) static_branch_enable(&_page_poisoning_enabled); page_poison=on needs to override init_on_free=1. Before the change it did not work as expected for the following case: - have PAGE_POISONING=y - have page_poison unset - have !ARCH_SUPPORTS_DEBUG_PAGEALLOC arch (like ia64) - have init_on_free=1 - have debug_pagealloc=1 That way we get both keys enabled: - static_branch_enable(&init_on_free); - static_branch_enable(&_page_poisoning_enabled); which leads to poisoned pages returned for __GFP_ZERO pages. After the change we execute only: - static_branch_enable(&_page_poisoning_enabled); and ignore init_on_free=1. Acked-by: Vlastimil Babka Fixes: 8db26a3d4735 ("mm, page_poison: use static key more efficiently") Cc: CC: Andrew Morton CC: linux-mm@kvack.org CC: David Hildenbrand CC: Andrey Konovalov Link: https://lkml.org/lkml/2021/3/26/443 Signed-off-by: Sergei Trofimovich Reviewed-by: David Hildenbrand --- Change since v2: - Added 'Fixes:' and 'CC: stable@' suggested by Vlastimil and David - Renamed local variable to 'page_poisoning_requested' for consistency suggested by David - Simplified initialization of page_poisoning_requested suggested by David - Added 'Acked-by: Vlastimil' mm/page_alloc.c | 30 +++++++++++++++++------------- 1 file changed, 17 insertions(+), 13 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index cfc72873961d..4bb3cdfc47f8 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -764,32 +764,36 @@ static inline void clear_page_guard(struct zone *zone, struct page *page, */ void init_mem_debugging_and_hardening(void) { + bool page_poisoning_requested = false; + +#ifdef CONFIG_PAGE_POISONING + /* + * Page poisoning is debug page alloc for some arches. If + * either of those options are enabled, enable poisoning. + */ + if (page_poisoning_enabled() || + (!IS_ENABLED(CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC) && + debug_pagealloc_enabled())) { + static_branch_enable(&_page_poisoning_enabled); + page_poisoning_requested = true; + } +#endif + if (_init_on_alloc_enabled_early) { - if (page_poisoning_enabled()) + if (page_poisoning_requested) pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, " "will take precedence over init_on_alloc\n"); else static_branch_enable(&init_on_alloc); } if (_init_on_free_enabled_early) { - if (page_poisoning_enabled()) + if (page_poisoning_requested) pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, " "will take precedence over init_on_free\n"); else static_branch_enable(&init_on_free); } -#ifdef CONFIG_PAGE_POISONING - /* - * Page poisoning is debug page alloc for some arches. If - * either of those options are enabled, enable poisoning. - */ - if (page_poisoning_enabled() || - (!IS_ENABLED(CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC) && - debug_pagealloc_enabled())) - static_branch_enable(&_page_poisoning_enabled); -#endif - #ifdef CONFIG_DEBUG_PAGEALLOC if (!debug_pagealloc_enabled()) return;