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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,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 E1AD2C4360C for ; Fri, 4 Oct 2019 07:38:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B61F420862 for ; Fri, 4 Oct 2019 07:38:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730629AbfJDHiG (ORCPT ); Fri, 4 Oct 2019 03:38:06 -0400 Received: from mailgw02.mediatek.com ([210.61.82.184]:27739 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1727326AbfJDHiF (ORCPT ); Fri, 4 Oct 2019 03:38:05 -0400 X-UUID: 4ac84daae92845f4b4b3b9b40615446e-20191004 X-UUID: 4ac84daae92845f4b4b3b9b40615446e-20191004 Received: from mtkcas09.mediatek.inc [(172.21.101.178)] by mailgw02.mediatek.com (envelope-from ) (Cellopoint E-mail Firewall v4.1.10 Build 0809 with TLS) with ESMTP id 482322489; Fri, 04 Oct 2019 15:37:57 +0800 Received: from mtkcas08.mediatek.inc (172.21.101.126) by mtkmbs07n2.mediatek.inc (172.21.101.141) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Fri, 4 Oct 2019 15:37:55 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by mtkcas08.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1395.4 via Frontend Transport; Fri, 4 Oct 2019 15:37:55 +0800 From: Miles Chen To: Andrew Morton CC: , , , , Miles Chen , Vlastimil Babka , Michal Hocko Subject: [PATCH] mm/page_owner: fix incorrect looping in __set_page_owner_handle() Date: Fri, 4 Oct 2019 15:37:55 +0800 Message-ID: <20191004073755.3228-1-miles.chen@mediatek.com> X-Mailer: git-send-email 2.18.0 MIME-Version: 1.0 Content-Type: text/plain X-MTK: N Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In __set_page_owner_handle(), we should loop over page [0...(1 << order) - 1] and setup their page_owner structures. Currently, __set_page_owner_handle() update page_ext at the end of the loop, sets the page_owner of (page + 0) twice and misses the page_owner of (page + (1 << order) - 1). Fix it by updating the page_ext at the start of the loop. In i == 0 case: for (i = 0; i < (1 << order); i++) { page_owner = get_page_owner(page_ext); <- page_ext belongs to page + 0 ... page_ext = lookup_page_ext(page + i); <- lookup_page_ext(page + 0) } Cc: Andrew Morton Cc: Vlastimil Babka Cc: Michal Hocko Signed-off-by: Miles Chen Fixes: 7e2f2a0cd17c ("mm, page_owner: record page owner for each subpage") --- mm/page_owner.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/mm/page_owner.c b/mm/page_owner.c index dee931184788..110c3e1987f2 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -178,6 +178,7 @@ static inline void __set_page_owner_handle(struct page *page, int i; for (i = 0; i < (1 << order); i++) { + page_ext = lookup_page_ext(page + i); page_owner = get_page_owner(page_ext); page_owner->handle = handle; page_owner->order = order; @@ -185,8 +186,6 @@ static inline void __set_page_owner_handle(struct page *page, page_owner->last_migrate_reason = -1; __set_bit(PAGE_EXT_OWNER, &page_ext->flags); __set_bit(PAGE_EXT_OWNER_ACTIVE, &page_ext->flags); - - page_ext = lookup_page_ext(page + i); } } -- 2.18.0