From 1514e1fb2a52d6fcbb2321894d41f1f4ea54c024 Mon Sep 17 00:00:00 2001
From: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Date: Fri, 23 Feb 2024 09:46:19 +0100
Subject: [PATCH] media: mc: mark the media devnode as registered from the,
start
commit 4bc60736154bc9e0e39d3b88918f5d3762ebe5e0 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: cf4b9211b568 ("[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>
---
drivers/media/mc/mc-devnode.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/media/mc/mc-devnode.c b/drivers/media/mc/mc-devnode.c
index f11382afe23b..f249199dc616 100644
--- a/drivers/media/mc/mc-devnode.c
+++ b/drivers/media/mc/mc-devnode.c
@@ -246,15 +246,14 @@ 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: