On Thu, Dec 06, 2012 at 01:44:57PM +0100, Benedikt Spranger wrote: > 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 <[email protected]> > --- > 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;
Where is that needed? I won't add a new element to struct uio_info without an in-kernel user. Thanks, Hans -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
