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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 D1947C433E0 for ; Mon, 15 Jun 2020 12:58:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AFE72207DA for ; Mon, 15 Jun 2020 12:58:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730176AbgFOM6A (ORCPT ); Mon, 15 Jun 2020 08:58:00 -0400 Received: from pegase1.c-s.fr ([93.17.236.30]:2744 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729766AbgFOM57 (ORCPT ); Mon, 15 Jun 2020 08:57:59 -0400 Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 49lrwP0gRdz9v1fj; Mon, 15 Jun 2020 14:57:57 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id 8xehc990nQE6; Mon, 15 Jun 2020 14:57:57 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 49lrwN70rkz9v1fM; Mon, 15 Jun 2020 14:57:56 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 6C7A08B792; Mon, 15 Jun 2020 14:57:57 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id kNn5IA9igqIr; Mon, 15 Jun 2020 14:57:57 +0200 (CEST) Received: from pc16570vm.idsi0.si.c-s.fr (po15451.idsi0.si.c-s.fr [172.25.230.104]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 23A048B75F; Mon, 15 Jun 2020 14:57:57 +0200 (CEST) Received: by pc16570vm.idsi0.si.c-s.fr (Postfix, from userid 0) id 1921265B0E; Mon, 15 Jun 2020 12:57:57 +0000 (UTC) Message-Id: In-Reply-To: References: From: Christophe Leroy Subject: [PATCH 1/3] mm/gup: Use huge_ptep_get() in gup_hugepte() To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Will Deacon , Andrew Morton , "Peter Zijlstra (Intel)" Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org Date: Mon, 15 Jun 2020 12:57:57 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org gup_hugepte() reads hugepage table entries, it can't read them directly, huge_ptep_get() must be used. Fixes: 2ab3a0a02905 ("READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses") Cc: Will Deacon Signed-off-by: Christophe Leroy --- mm/gup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/gup.c b/mm/gup.c index de9e36262ccb..761df4944ef5 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -2425,7 +2425,7 @@ static int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr, if (pte_end < end) end = pte_end; - pte = READ_ONCE(*ptep); + pte = huge_ptep_get(ptep); if (!pte_access_permitted(pte, flags & FOLL_WRITE)) return 0; -- 2.25.0