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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 89356C433EF for ; Mon, 13 Sep 2021 11:51:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 62FF960FA0 for ; Mon, 13 Sep 2021 11:51:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239714AbhIMLwR (ORCPT ); Mon, 13 Sep 2021 07:52:17 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:9034 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236326AbhIMLwQ (ORCPT ); Mon, 13 Sep 2021 07:52:16 -0400 Received: from dggeme703-chm.china.huawei.com (unknown [172.30.72.57]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4H7Pt14yQGzVgCC; Mon, 13 Sep 2021 19:50:01 +0800 (CST) Received: from huawei.com (10.175.124.27) by dggeme703-chm.china.huawei.com (10.1.199.99) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.8; Mon, 13 Sep 2021 19:50:59 +0800 From: Miaohe Lin To: CC: , , , , , Subject: [PATCH v2] mm/page_isolation: fix potential missing call to unset_migratetype_isolate() Date: Mon, 13 Sep 2021 19:51:25 +0800 Message-ID: <20210913115125.33617-1-linmiaohe@huawei.com> X-Mailer: git-send-email 2.23.0 MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.124.27] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To dggeme703-chm.china.huawei.com (10.1.199.99) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In start_isolate_page_range() undo path, pfn_to_online_page() just checks the first pfn in a pageblock while __first_valid_page() will traverse the pageblock until the first online pfn is found. So we may miss the call to unset_migratetype_isolate() in undo path and pages will remain isolated unexpectedly. Fix this by calling undo_isolate_page_range() and this will also help to simplify the code further. Fixes: 2ce13640b3f4 ("mm: __first_valid_page skip over offline pages") Signed-off-by: Miaohe Lin Cc: --- v1->v2: Simplify the code further per David Hildenbrand. --- mm/page_isolation.c | 20 +++----------------- 1 file changed, 3 insertions(+), 17 deletions(-) diff --git a/mm/page_isolation.c b/mm/page_isolation.c index a95c2c6562d0..f93cc63d8fa1 100644 --- a/mm/page_isolation.c +++ b/mm/page_isolation.c @@ -183,7 +183,6 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn, unsigned migratetype, int flags) { unsigned long pfn; - unsigned long undo_pfn; struct page *page; BUG_ON(!IS_ALIGNED(start_pfn, pageblock_nr_pages)); @@ -193,25 +192,12 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn, pfn < end_pfn; pfn += pageblock_nr_pages) { page = __first_valid_page(pfn, pageblock_nr_pages); - if (page) { - if (set_migratetype_isolate(page, migratetype, flags)) { - undo_pfn = pfn; - goto undo; - } + if (page && set_migratetype_isolate(page, migratetype, flags)) { + undo_isolate_page_range(start_pfn, pfn, migratetype); + return -EBUSY; } } return 0; -undo: - for (pfn = start_pfn; - pfn < undo_pfn; - pfn += pageblock_nr_pages) { - struct page *page = pfn_to_online_page(pfn); - if (!page) - continue; - unset_migratetype_isolate(page, migratetype); - } - - return -EBUSY; } /* -- 2.23.0