media: mc: mark the media devnode as registered from the, start

commit 4bc6073615 upstream.

First the media device node was created, and if successful it was
marked as 'registered'. This leaves a small race condition where
an application can open the device node and get an error back
because the 'registered' flag was not yet set.

Change the order: first set the 'registered' flag, then actually
register the media device node. If that fails, then clear the flag.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Fixes: cf4b9211b5 ("[media] media: Media device node support")
Cc: stable@vger.kernel.org
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Hans Verkuil 2024-02-23 09:46:19 +01:00 committed by Greg Kroah-Hartman
parent bee9440bc0
commit 6a792a5588

View File

@ -245,15 +245,14 @@ int __must_check media_devnode_register(struct media_device *mdev,
kobject_set_name(&devnode->cdev.kobj, "media%d", devnode->minor);
/* Part 3: Add the media and char device */
set_bit(MEDIA_FLAG_REGISTERED, &devnode->flags);
ret = cdev_device_add(&devnode->cdev, &devnode->dev);
if (ret < 0) {
clear_bit(MEDIA_FLAG_REGISTERED, &devnode->flags);
pr_err("%s: cdev_device_add failed\n", __func__);
goto cdev_add_error;
}
/* Part 4: Activate this minor. The char device can now be used. */
set_bit(MEDIA_FLAG_REGISTERED, &devnode->flags);
return 0;
cdev_add_error: