Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934040AbbBCXZk (ORCPT ); Tue, 3 Feb 2015 18:25:40 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:55344 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933517AbbBCXZV (ORCPT ); Tue, 3 Feb 2015 18:25:21 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Steve Capper , Will Deacon , Hou Pengyang Subject: [PATCH 3.10 19/51] ARM: mm: correct pte_same behaviour for LPAE. Date: Tue, 3 Feb 2015 15:17:01 -0800 Message-Id: <20150203231725.172971723@linuxfoundation.org> X-Mailer: git-send-email 2.2.2 In-Reply-To: <20150203231724.582537862@linuxfoundation.org> References: <20150203231724.582537862@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2172 Lines: 60 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Steve Capper commit dde1b65110353517816bcbc58539463396202244 upstream. For 3 levels of paging the PTE_EXT_NG bit will be set for user address ptes that are written to a page table but not for ptes created with mk_pte. This can cause some comparison tests made by pte_same to fail spuriously and lead to other problems. To correct this behaviour, we mask off PTE_EXT_NG for any pte that is present before running the comparison. Signed-off-by: Steve Capper Reviewed-by: Will Deacon Cc: Hou Pengyang Signed-off-by: Greg Kroah-Hartman --- arch/arm/include/asm/pgtable-3level.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) --- a/arch/arm/include/asm/pgtable-3level.h +++ b/arch/arm/include/asm/pgtable-3level.h @@ -166,6 +166,23 @@ static inline pmd_t *pmd_offset(pud_t *p clean_pmd_entry(pmdp); \ } while (0) +/* + * For 3 levels of paging the PTE_EXT_NG bit will be set for user address ptes + * that are written to a page table but not for ptes created with mk_pte. + * + * In hugetlb_no_page, a new huge pte (new_pte) is generated and passed to + * hugetlb_cow, where it is compared with an entry in a page table. + * This comparison test fails erroneously leading ultimately to a memory leak. + * + * To correct this behaviour, we mask off PTE_EXT_NG for any pte that is + * present before running the comparison. + */ +#define __HAVE_ARCH_PTE_SAME +#define pte_same(pte_a,pte_b) ((pte_present(pte_a) ? pte_val(pte_a) & ~PTE_EXT_NG \ + : pte_val(pte_a)) \ + == (pte_present(pte_b) ? pte_val(pte_b) & ~PTE_EXT_NG \ + : pte_val(pte_b))) + #define set_pte_ext(ptep,pte,ext) cpu_set_pte_ext(ptep,__pte(pte_val(pte)|(ext))) #endif /* __ASSEMBLY__ */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/