From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:60146 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1946974AbcHRK4f (ORCPT ); Thu, 18 Aug 2016 06:56:35 -0400 Subject: Patch "ARM: 8579/1: mm: Fix definition of pmd_mknotpresent" has been added to the 3.14-stable tree To: steve.capper@arm.com, catalin.marinas@arm.com, gregkh@linuxfoundation.org, kirill.shutemov@linux.intel.com, linux@armlinux.org.uk, rmk+kernel@arm.linux.org.uk, stable@vger.kernel.org, will.deacon@arm.com Cc: , From: Date: Thu, 18 Aug 2016 12:56:38 +0200 Message-ID: <1471517798182212@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled ARM: 8579/1: mm: Fix definition of pmd_mknotpresent to the 3.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: arm-8579-1-mm-fix-definition-of-pmd_mknotpresent.patch and it can be found in the queue-3.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 56530f5d2ddc9b9fade7ef8db9cb886e9dc689b5 Mon Sep 17 00:00:00 2001 From: Steve Capper Date: Tue, 7 Jun 2016 17:58:06 +0100 Subject: ARM: 8579/1: mm: Fix definition of pmd_mknotpresent From: Steve Capper 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.") Cc: # 3.11+ 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: Greg Kroah-Hartman --- This is a backport of commit 56530f5d2ddc ("ARM: 8579/1: mm: Fix definition of pmd_mknotpresent") to the 3.14.x stable kernel and earlier because the original patch does not apply cleanly. As noted in the "Cc: stable" tag above, this patch requires commit 624531886987 ("ARM: 8578/1: mm: ensure pmd_present only checks the valid bit"), already queued for 3.14.x stable kernel. arch/arm/include/asm/pgtable-3level.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/arch/arm/include/asm/pgtable-3level.h +++ b/arch/arm/include/asm/pgtable-3level.h @@ -243,8 +243,11 @@ 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) { Patches currently in stable-queue which might be from steve.capper@arm.com are queue-3.14/arm-8579-1-mm-fix-definition-of-pmd_mknotpresent.patch