From patchwork Tue Aug 13 09:08:36 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benedikt Spranger X-Patchwork-Id: 266753 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id CFD272C00EE for ; Tue, 13 Aug 2013 19:09:41 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755993Ab3HMJJR (ORCPT ); Tue, 13 Aug 2013 05:09:17 -0400 Received: from www.linutronix.de ([62.245.132.108]:48271 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754506Ab3HMJIv (ORCPT ); Tue, 13 Aug 2013 05:08:51 -0400 Received: from p5492f3b2.dip0.t-ipconnect.de ([84.146.243.178] helo=mitra.tec.linutronix.de ident=mdkuser) by Galois.linutronix.de with esmtpsa (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.72) (envelope-from ) id 1V9Aaw-0006Td-Dh; Tue, 13 Aug 2013 11:08:50 +0200 From: Benedikt Spranger To: netdev@vger.kernel.org Cc: Alexander Frank , Sebastian Andrzej Siewior , Benedikt Spranger , "Hans J. Koch" , Greg Kroah-Hartman , Holger Dengler Subject: [PATCH 1/7] uio: add module owner to prevent inappropriate module unloading Date: Tue, 13 Aug 2013 11:08:36 +0200 Message-Id: <1376384922-8519-3-git-send-email-b.spranger@linutronix.de> X-Mailer: git-send-email 1.8.4.rc2 In-Reply-To: <1376384922-8519-1-git-send-email-b.spranger@linutronix.de> References: <1376384922-8519-1-git-send-email-b.spranger@linutronix.de> X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1, SHORTCIRCUIT=-0.0001, URIBL_BLOCKED=0.001 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org If an UIO device is created by another driver (MFD for instance) it has to be ensured that the MFD driver isn't removed while the UIO is still in use. This patch adds a reference to the parent driver which does module refcounting in order to avoid an too early removal. Cc: "Hans J. Koch" Cc: Greg Kroah-Hartman Signed-off-by: Benedikt Spranger Signed-off-by: Holger Dengler --- drivers/uio/uio.c | 9 +++++++++ include/linux/uio_driver.h | 2 ++ 2 files changed, 11 insertions(+) diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c index 3b96f18..9a95220 100644 --- a/drivers/uio/uio.c +++ b/drivers/uio/uio.c @@ -444,6 +444,11 @@ static int uio_open(struct inode *inode, struct file *filep) goto out; } + if (!try_module_get(idev->info->owner)) { + ret = -ENODEV; + goto err_get_module; + } + listener = kmalloc(sizeof(*listener), GFP_KERNEL); if (!listener) { ret = -ENOMEM; @@ -465,6 +470,9 @@ err_infoopen: kfree(listener); err_alloc_listener: + module_put(idev->info->owner); + +err_get_module: module_put(idev->owner); out: @@ -488,6 +496,7 @@ static int uio_release(struct inode *inode, struct file *filep) if (idev->info->release) ret = idev->info->release(idev->info, inode); + module_put(idev->info->owner); module_put(idev->owner); kfree(listener); return ret; diff --git a/include/linux/uio_driver.h b/include/linux/uio_driver.h index 1ad4724..99f1696 100644 --- a/include/linux/uio_driver.h +++ b/include/linux/uio_driver.h @@ -80,6 +80,7 @@ struct uio_device; * @open: open operation for this uio device * @release: release operation for this uio device * @irqcontrol: disable/enable irqs when 0/1 is written to /dev/uioX + * @owner: module which created the uio device incase */ struct uio_info { struct uio_device *uio_dev; @@ -95,6 +96,7 @@ struct uio_info { int (*open)(struct uio_info *info, struct inode *inode); int (*release)(struct uio_info *info, struct inode *inode); int (*irqcontrol)(struct uio_info *info, s32 irq_on); + struct module *owner; }; extern int __must_check