From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754984AbcHSHQp (ORCPT ); Fri, 19 Aug 2016 03:16:45 -0400 Received: from mx2.suse.de ([195.135.220.15]:50045 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755565AbcHSHMK (ORCPT ); Fri, 19 Aug 2016 03:12:10 -0400 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Steve Capper , Russell King , Catalin Marinas , Russell King , Jiri Slaby Subject: [PATCH 3.12 081/100] ARM: 8579/1: mm: Fix definition of pmd_mknotpresent Date: Fri, 19 Aug 2016 09:11:20 +0200 Message-Id: <6bd6ca580cf4c5665c0cf01c991ba020ea680e85.1471589700.git.jslaby@suse.cz> X-Mailer: git-send-email 2.9.3 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Steve Capper 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 56530f5d2ddc9b9fade7ef8db9cb886e9dc689b5 upstream. Currently pmd_mknotpresent will use a zero entry to respresent an invalidated pmd. Unfortunately this definition clashes with pmd_none, thus it is possible for a race condition to occur if zap_pmd_range sees pmd_none whilst __split_huge_pmd_locked is running too with pmdp_invalidate just called. This patch fixes the race condition by modifying pmd_mknotpresent to create non-zero faulting entries (as is done in other architectures), removing the ambiguity with pmd_none. [catalin.marinas@arm.com: using L_PMD_SECT_VALID instead of PMD_TYPE_SECT] Fixes: 8d9625070073 ("ARM: mm: Transparent huge page support for LPAE systems.") Reported-by: Kirill A. Shutemov Acked-by: Will Deacon Cc: Russell King Signed-off-by: Steve Capper Signed-off-by: Catalin Marinas Signed-off-by: Russell King Signed-off-by: Jiri Slaby --- arch/arm/include/asm/pgtable-3level.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h index 8afa39f81477..0f153b62d253 100644 --- a/arch/arm/include/asm/pgtable-3level.h +++ b/arch/arm/include/asm/pgtable-3level.h @@ -237,8 +237,11 @@ PMD_BIT_FUNC(mkyoung, |= PMD_SECT_AF); #define pfn_pmd(pfn,prot) (__pmd(((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot))) #define mk_pmd(page,prot) pfn_pmd(page_to_pfn(page),prot) -/* represent a notpresent pmd by zero, this is used by pmdp_invalidate */ -#define pmd_mknotpresent(pmd) (__pmd(0)) +/* represent a notpresent pmd by faulting entry, this is used by pmdp_invalidate */ +static inline pmd_t pmd_mknotpresent(pmd_t pmd) +{ + return __pmd(pmd_val(pmd) & ~L_PMD_SECT_VALID); +} static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot) { -- 2.9.3