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=-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=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 721D8C43460 for ; Mon, 12 Apr 2021 03:47:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 509366109E for ; Mon, 12 Apr 2021 03:47:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236695AbhDLDsE (ORCPT ); Sun, 11 Apr 2021 23:48:04 -0400 Received: from foss.arm.com ([217.140.110.172]:34980 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236541AbhDLDr5 (ORCPT ); Sun, 11 Apr 2021 23:47:57 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A7EF331B; Sun, 11 Apr 2021 20:47:39 -0700 (PDT) Received: from p8cg001049571a15.arm.com (unknown [10.163.72.70]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id F29143F694; Sun, 11 Apr 2021 20:47:37 -0700 (PDT) From: Anshuman Khandual To: linux-mm@kvack.org, akpm@linux-foundation.org Cc: Anshuman Khandual , David Hildenbrand , linux-kernel@vger.kernel.org Subject: [PATCH V2] mm/page_alloc: Ensure that HUGETLB_PAGE_ORDER is less than MAX_ORDER Date: Mon, 12 Apr 2021 09:18:22 +0530 Message-Id: <1618199302-29335-1-git-send-email-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org pageblock_order must always be less than MAX_ORDER, otherwise it might lead to an warning during boot. A similar problem got fixed on arm64 platform with the commit 79cc2ed5a716 ("arm64/mm: Drop THP conditionality from FORCE_MAX_ZONEORDER"). Assert the above condition before HUGETLB_PAGE_ORDER gets assigned as pageblock_order. This will help detect the problem earlier on platforms where HUGETLB_PAGE_SIZE_VARIABLE is enabled. Cc: David Hildenbrand Cc: Andrew Morton Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual --- Changes in V2: - Changed WARN_ON() to BUILD_BUG_ON() per David Changes in V1: https://patchwork.kernel.org/project/linux-mm/patch/1617947717-2424-1-git-send-email-anshuman.khandual@arm.com/ mm/page_alloc.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index cfc72873961d..19283bff4bec 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6875,10 +6875,17 @@ void __init set_pageblock_order(void) if (pageblock_order) return; - if (HPAGE_SHIFT > PAGE_SHIFT) + if (HPAGE_SHIFT > PAGE_SHIFT) { + /* + * pageblock_order must always be less than + * MAX_ORDER. So does HUGETLB_PAGE_ORDER if + * that is being assigned here. + */ + BUILD_BUG_ON(HUGETLB_PAGE_ORDER >= MAX_ORDER); order = HUGETLB_PAGE_ORDER; - else + } else { order = MAX_ORDER - 1; + } /* * Assume the largest contiguous order of interest is a huge page. -- 2.20.1