Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932937AbcKPR35 (ORCPT ); Wed, 16 Nov 2016 12:29:57 -0500 Received: from mga04.intel.com ([192.55.52.120]:37959 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932324AbcKPR3z (ORCPT ); Wed, 16 Nov 2016 12:29:55 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.31,500,1473145200"; d="scan'208";a="32045280" Subject: [PATCH] device-dax: fail all private mapping attempts From: Dan Williams To: linux-nvdimm@ml01.01.org Cc: linux-mm@kvack.org, Dave Hansen , linux-kernel@vger.kernel.org, stable@vger.kernel.org, Pawel Lebioda Date: Wed, 16 Nov 2016 09:26:53 -0800 Message-ID: <147931721349.37471.4835899844582504197.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.17.1-9-g687f MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1297 Lines: 30 The device-dax implementation originally tried to be tricky and allow private read-only mappings, but in the process allowed writable MAP_PRIVATE + MAP_NORESERVE mappings. For simplicity and predictability just fail all private mapping attempts since device-dax memory is statically allocated and will never support overcommit. Cc: Cc: Dave Hansen Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap") Reported-by: Pawel Lebioda Signed-off-by: Dan Williams --- drivers/dax/dax.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c index 0e499bfca41c..3d94ff20fdca 100644 --- a/drivers/dax/dax.c +++ b/drivers/dax/dax.c @@ -270,8 +270,8 @@ static int check_vma(struct dax_dev *dax_dev, struct vm_area_struct *vma, if (!dax_dev->alive) return -ENXIO; - /* prevent private / writable mappings from being established */ - if ((vma->vm_flags & (VM_NORESERVE|VM_SHARED|VM_WRITE)) == VM_WRITE) { + /* prevent private mappings from being established */ + if ((vma->vm_flags & VM_SHARED) != VM_SHARED) { dev_info(dev, "%s: %s: fail, attempted private mapping\n", current->comm, func); return -EINVAL;