From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752035Ab2KJN7v (ORCPT ); Sat, 10 Nov 2012 08:59:51 -0500 Received: from mail-da0-f46.google.com ([209.85.210.46]:47743 "EHLO mail-da0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751640Ab2KJN7p (ORCPT ); Sat, 10 Nov 2012 08:59:45 -0500 From: Jiang Liu To: Alex Williamson , Greg Kroah-Hartman Cc: Jiang Liu , Joerg Roedel , Yinghai Lu , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Hanjun Guo Subject: [RFC PATCH 6/6] VFIO: use ACCESS_ONCE() to guard access to dev->driver Date: Sat, 10 Nov 2012 21:57:19 +0800 Message-Id: <1352555839-18961-6-git-send-email-jiang.liu@huawei.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1352555839-18961-1-git-send-email-jiang.liu@huawei.com> References: <1352555839-18961-1-git-send-email-jiang.liu@huawei.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jiang Liu Comments from dev_driver_string(), /* dev->driver can change to NULL underneath us because of unbinding, * so be careful about accessing it. */ So use ACCESS_ONCE() to guard access to dev->driver field. Signed-off-by: Jiang Liu --- drivers/vfio/vfio.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index 18714b9..f158e42 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -520,8 +520,9 @@ static bool vfio_whitelisted_driver(struct device_driver *drv) static int vfio_dev_viable(struct device *dev, void *data) { struct vfio_device_driver *driver; + struct device_driver *drv = ACCESS_ONCE(dev->driver); - if (!dev->driver || vfio_whitelisted_driver(dev->driver)) + if (!drv || vfio_whitelisted_driver(drv)) return 0; mutex_lock(&vfio.device_drivers_lock); -- 1.7.9.5