From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:40930 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752805AbdCMIrI (ORCPT ); Mon, 13 Mar 2017 04:47:08 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ross Zwisler , Dan Williams , Dave Hansen , Xiong Zhou , Ingo Molnar , "H. Peter Anvin" , Thomas Gleixner , Andrew Morton , Linus Torvalds Subject: [PATCH 4.10 69/75] x86, mm: fix gup_pte_range() vs DAX mappings Date: Mon, 13 Mar 2017 16:44:18 +0800 Message-Id: <20170313083415.229684692@linuxfoundation.org> In-Reply-To: <20170313083411.408297387@linuxfoundation.org> References: <20170313083411.408297387@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dan Williams commit ef947b2529f918d9606533eb9c32b187ed6a5ede upstream. gup_pte_range() fails to check pte_allows_gup() before translating a DAX pte entry, pte_devmap(), to a page. This allows writes to read-only mappings, and bypasses the DAX cacheline dirty tracking due to missed 'mkwrite' faults. The gup_huge_pmd() path and the gup_huge_pud() path correctly check pte_allows_gup() before checking for _devmap() entries. Fixes: 3565fce3a659 ("mm, x86: get_user_pages() for dax mappings") Link: http://lkml.kernel.org/r/148804251312.36605.12665024794196605053.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Ross Zwisler Signed-off-by: Dan Williams Reported-by: Dave Hansen Reported-by: Ross Zwisler Cc: Xiong Zhou Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- arch/x86/mm/gup.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/arch/x86/mm/gup.c +++ b/arch/x86/mm/gup.c @@ -120,6 +120,11 @@ static noinline int gup_pte_range(pmd_t return 0; } + if (!pte_allows_gup(pte_val(pte), write)) { + pte_unmap(ptep); + return 0; + } + if (pte_devmap(pte)) { pgmap = get_dev_pagemap(pte_pfn(pte), pgmap); if (unlikely(!pgmap)) { @@ -127,8 +132,7 @@ static noinline int gup_pte_range(pmd_t pte_unmap(ptep); return 0; } - } else if (!pte_allows_gup(pte_val(pte), write) || - pte_special(pte)) { + } else if (pte_special(pte)) { pte_unmap(ptep); return 0; }