From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754529Ab3AXD34 (ORCPT ); Wed, 23 Jan 2013 22:29:56 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:44239 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754341Ab3AXD3X (ORCPT ); Wed, 23 Jan 2013 22:29:23 -0500 From: Herton Ronaldo Krzesinski To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Ian Abbott , Greg Kroah-Hartman , Herton Ronaldo Krzesinski Subject: [PATCH 28/74] staging: comedi: prevent auto-unconfig of manually configured devices Date: Thu, 24 Jan 2013 01:26:40 -0200 Message-Id: <1358998046-613-29-git-send-email-herton.krzesinski@canonical.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1358998046-613-1-git-send-email-herton.krzesinski@canonical.com> References: <1358998046-613-1-git-send-email-herton.krzesinski@canonical.com> X-Extended-Stable: 3.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.5.7.4 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Ian Abbott commit 7d3135af399e92cf4c9bbc5f86b6c140aab3b88c upstream. When a low-level comedi driver auto-configures a device, a `struct comedi_dev_file_info` is allocated (as well as a `struct comedi_device`) by `comedi_alloc_board_minor()`. A pointer to the hardware `struct device` is stored as a cookie in the `struct comedi_dev_file_info`. When the low-level comedi driver auto-unconfigures the device, `comedi_auto_unconfig()` uses the cookie to find the `struct comedi_dev_file_info` so it can detach the comedi device from the driver, clean it up and free it. A problem arises if the user manually unconfigures and reconfigures the comedi device using the `COMEDI_DEVCONFIG` ioctl so that is no longer associated with the original hardware device. The problem is that the cookie is not cleared, so that a call to `comedi_auto_unconfig()` from the low-level driver will still find it, detach it, clean it up and free it. Stop this problem occurring by always clearing the `hardware_device` cookie in the `struct comedi_dev_file_info` whenever the `COMEDI_DEVCONFIG` ioctl call is successful. Signed-off-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman Signed-off-by: Herton Ronaldo Krzesinski --- drivers/staging/comedi/comedi_fops.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index d77219a..d231193 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -427,6 +427,9 @@ static long comedi_unlocked_ioctl(struct file *file, unsigned int cmd, if (cmd == COMEDI_DEVCONFIG) { rc = do_devconfig_ioctl(dev, (struct comedi_devconfig __user *)arg); + if (rc == 0) + /* Evade comedi_auto_unconfig(). */ + dev_file_info->hardware_device = NULL; goto done; } -- 1.7.9.5