From patchwork Mon Mar 6 14:20:50 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Reshetova, Elena" X-Patchwork-Id: 9606953 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id D24D06046A for ; Mon, 6 Mar 2017 15:23:00 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C193B2838E for ; Mon, 6 Mar 2017 15:23:00 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B3D6128447; Mon, 6 Mar 2017 15:23:00 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 42C762838E for ; Mon, 6 Mar 2017 15:23:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932277AbdCFPWw (ORCPT ); Mon, 6 Mar 2017 10:22:52 -0500 Received: from mga04.intel.com ([192.55.52.120]:52309 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753887AbdCFPWP (ORCPT ); Mon, 6 Mar 2017 10:22:15 -0500 Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 06 Mar 2017 06:21:44 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,254,1484035200"; d="scan'208";a="72745861" Received: from rzetikx-mobl.ger.corp.intel.com (HELO elena-ThinkPad-X230.ger.corp.intel.com) ([10.249.41.1]) by fmsmga005.fm.intel.com with ESMTP; 06 Mar 2017 06:21:38 -0800 From: Elena Reshetova To: gregkh@linuxfoundation.org Cc: linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, netdev@vger.kernel.org, linux1394-devel@lists.sourceforge.net, linux-bcache@vger.kernel.org, linux-raid@vger.kernel.org, linux-media@vger.kernel.org, devel@linuxdriverproject.org, linux-pci@vger.kernel.org, linux-s390@vger.kernel.org, fcoe-devel@open-fcoe.org, linux-scsi@vger.kernel.org, open-iscsi@googlegroups.com, devel@driverdev.osuosl.org, target-devel@vger.kernel.org, linux-serial@vger.kernel.org, linux-usb@vger.kernel.org, peterz@infradead.org, Elena Reshetova , Hans Liljestrand , Kees Cook , David Windsor Subject: [PATCH 03/29] drivers, char: convert vma_data.refcnt from atomic_t to refcount_t Date: Mon, 6 Mar 2017 16:20:50 +0200 Message-Id: <1488810076-3754-4-git-send-email-elena.reshetova@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1488810076-3754-1-git-send-email-elena.reshetova@intel.com> References: <1488810076-3754-1-git-send-email-elena.reshetova@intel.com> Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova Signed-off-by: Hans Liljestrand Signed-off-by: Kees Cook Signed-off-by: David Windsor --- drivers/char/mspec.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/char/mspec.c b/drivers/char/mspec.c index a9c2fa3..7b75669 100644 --- a/drivers/char/mspec.c +++ b/drivers/char/mspec.c @@ -43,6 +43,7 @@ #include #include #include +#include #include #include #include @@ -89,7 +90,7 @@ static int is_sn2; * protect in fork case where multiple tasks share the vma_data. */ struct vma_data { - atomic_t refcnt; /* Number of vmas sharing the data. */ + refcount_t refcnt; /* Number of vmas sharing the data. */ spinlock_t lock; /* Serialize access to this structure. */ int count; /* Number of pages allocated. */ enum mspec_page_type type; /* Type of pages allocated. */ @@ -144,7 +145,7 @@ mspec_open(struct vm_area_struct *vma) struct vma_data *vdata; vdata = vma->vm_private_data; - atomic_inc(&vdata->refcnt); + refcount_inc(&vdata->refcnt); } /* @@ -162,7 +163,7 @@ mspec_close(struct vm_area_struct *vma) vdata = vma->vm_private_data; - if (!atomic_dec_and_test(&vdata->refcnt)) + if (!refcount_dec_and_test(&vdata->refcnt)) return; last_index = (vdata->vm_end - vdata->vm_start) >> PAGE_SHIFT; @@ -274,7 +275,7 @@ mspec_mmap(struct file *file, struct vm_area_struct *vma, vdata->vm_end = vma->vm_end; vdata->type = type; spin_lock_init(&vdata->lock); - atomic_set(&vdata->refcnt, 1); + refcount_set(&vdata->refcnt, 1); vma->vm_private_data = vdata; vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;