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Message-Id: <1354797897-23423-3-git-send-email-b.spranger@linutronix.de> Date: Thu, 6 Dec 2012 13:44:57 +0100 From: Benedikt Spranger <b.spranger@...utronix.de> To: linux-kernel@...r.kernel.org Cc: hjk@...sjkoch.de, gregkh@...uxfoundation.org, Alexander.Frank@...rspaecher.com, Benedikt Spranger <b.spranger@...utronix.de> Subject: [PATCH 2/2] uio: avoid module unloding of in module created UIO devices A kernel module can create a uio device. Get a reference to the module, if the UIO device is in use. Otherwise the device can be removed and a uio write or an access to am mmaped memory can cause a kernel Oops or other strange effects. Signed-off-by: Benedikt Spranger <b.spranger@...utronix.de> --- drivers/uio/uio.c | 8 ++++++++ include/linux/uio_driver.h | 1 + 2 files changed, 9 insertions(+) diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c index b96499a..3b62da0 100644 --- a/drivers/uio/uio.c +++ b/drivers/uio/uio.c @@ -446,6 +446,7 @@ static void uio_release_listener(struct kref *kref) idev->info->release(idev->info); module_put(idev->owner); + module_put(idev->info->owner); kfree(listener); } @@ -468,6 +469,11 @@ 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; @@ -493,6 +499,8 @@ err_infoopen: err_alloc_listener: module_put(idev->owner); +err_get_module: + module_put(idev->owner); out: return ret; diff --git a/include/linux/uio_driver.h b/include/linux/uio_driver.h index 1bc6493..2862de23 100644 --- a/include/linux/uio_driver.h +++ b/include/linux/uio_driver.h @@ -95,6 +95,7 @@ struct uio_info { int (*open)(struct uio_info *info); void (*release)(struct uio_info *info); int (*irqcontrol)(struct uio_info *info, s32 irq_on); + struct module *owner; }; extern int __must_check -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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