From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:45408 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751880AbbGaTiF (ORCPT ); Fri, 31 Jul 2015 15:38:05 -0400 Subject: Patch "arm64: Don't report clear pmds and puds as huge" has been added to the 4.1-stable tree To: christoffer.dall@linaro.org, catalin.marinas@arm.com, gregkh@linuxfoundation.org, marc.zyngier@arm.com, steve.capper@linaro.org Cc: , From: Date: Fri, 31 Jul 2015 12:38:02 -0700 Message-ID: <1438371482250165@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 arm64: Don't report clear pmds and puds as huge to the 4.1-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: arm64-don-t-report-clear-pmds-and-puds-as-huge.patch and it can be found in the queue-4.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From fd28f5d439fca77348c129d5b73043a56f8a0296 Mon Sep 17 00:00:00 2001 From: Christoffer Dall Date: Wed, 1 Jul 2015 14:08:31 +0200 Subject: arm64: Don't report clear pmds and puds as huge From: Christoffer Dall commit fd28f5d439fca77348c129d5b73043a56f8a0296 upstream. The current pmd_huge() and pud_huge() functions simply check if the table bit is not set and reports the entries as huge in that case. This is counter-intuitive as a clear pmd/pud cannot also be a huge pmd/pud, and it is inconsistent with at least arm and x86. To prevent others from making the same mistake as me in looking at code that calls these functions and to fix an issue with KVM on arm64 that causes memory corruption due to incorrect page reference counting resulting from this mistake, let's change the behavior. Signed-off-by: Christoffer Dall Reviewed-by: Steve Capper Acked-by: Marc Zyngier Fixes: 084bd29810a5 ("ARM64: mm: HugeTLB support.") Signed-off-by: Catalin Marinas Signed-off-by: Greg Kroah-Hartman --- arch/arm64/mm/hugetlbpage.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/arm64/mm/hugetlbpage.c +++ b/arch/arm64/mm/hugetlbpage.c @@ -40,13 +40,13 @@ int huge_pmd_unshare(struct mm_struct *m int pmd_huge(pmd_t pmd) { - return !(pmd_val(pmd) & PMD_TABLE_BIT); + return pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT); } int pud_huge(pud_t pud) { #ifndef __PAGETABLE_PMD_FOLDED - return !(pud_val(pud) & PUD_TABLE_BIT); + return pud_val(pud) && !(pud_val(pud) & PUD_TABLE_BIT); #else return 0; #endif Patches currently in stable-queue which might be from christoffer.dall@linaro.org are queue-4.1/arm64-don-t-report-clear-pmds-and-puds-as-huge.patch