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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 74D71C43334 for ; Wed, 22 Jun 2022 17:06:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1376940AbiFVRGe (ORCPT ); Wed, 22 Jun 2022 13:06:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42240 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1358339AbiFVRGb (ORCPT ); Wed, 22 Jun 2022 13:06:31 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 449C43EF06 for ; Wed, 22 Jun 2022 10:06:30 -0700 (PDT) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4LSqT36mZDzSh9m; Thu, 23 Jun 2022 01:03:03 +0800 (CST) Received: from huawei.com (10.175.124.27) by canpemm500002.china.huawei.com (7.192.104.244) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Thu, 23 Jun 2022 01:06:28 +0800 From: Miaohe Lin To: CC: , , , , , Subject: [PATCH 02/16] mm/huge_memory: access vm_page_prot with READ_ONCE in remove_migration_pmd Date: Thu, 23 Jun 2022 01:06:13 +0800 Message-ID: <20220622170627.19786-3-linmiaohe@huawei.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20220622170627.19786-1-linmiaohe@huawei.com> References: <20220622170627.19786-1-linmiaohe@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.124.27] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org vma->vm_page_prot is read lockless from the rmap_walk, it may be updated concurrently. Using READ_ONCE to prevent the risk of reading intermediate values. Signed-off-by: Miaohe Lin --- mm/huge_memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index fd6da053a13e..83fb6c3442ff 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3202,7 +3202,7 @@ void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) entry = pmd_to_swp_entry(*pvmw->pmd); get_page(new); - pmde = pmd_mkold(mk_huge_pmd(new, vma->vm_page_prot)); + pmde = pmd_mkold(mk_huge_pmd(new, READ_ONCE(vma->vm_page_prot))); if (pmd_swp_soft_dirty(*pvmw->pmd)) pmde = pmd_mksoft_dirty(pmde); if (is_writable_migration_entry(entry)) -- 2.23.0