media: mc: Clear minor number before put device

[ Upstream commit 8cfc8ce ]

The device minor should not be cleared after the device is released.

Fixes: 9e14868dc952 ("media: mc: Clear minor number reservation at unregistration time")
Cc: [email protected]
Reported-by: [email protected]
Closes: https://syzkaller.appspot.com/bug?extid=031d0cfd7c362817963f
Tested-by: [email protected]
Signed-off-by: Edward Adam Davis <[email protected]>
Signed-off-by: Sakari Ailus <[email protected]>
Signed-off-by: Hans Verkuil <[email protected]>
[ moved clear_bit from media_devnode_release callback to media_devnode_unregister before put_device ]
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: ea1davis

drivers/media/mc/mc-devnode.c

@@ -50,11 +50,6 @@ static void media_devnode_release(struct device *cd)
 {
 	struct media_devnode *devnode = to_media_devnode(cd);
 
-	mutex_lock(&media_devnode_lock);
-	/* Mark device node number as free */
-	clear_bit(devnode->minor, media_devnode_nums);
-	mutex_unlock(&media_devnode_lock);
-
 	/* Release media_devnode and perform other cleanups as needed. */
 	if (devnode->release)
 		devnode->release(devnode);
@@ -281,6 +276,7 @@ void media_devnode_unregister(struct media_devnode *devnode)
 	/* Delete the cdev on this minor as well */
 	cdev_device_del(&devnode->cdev, &devnode->dev);
 	devnode->media_dev = NULL;
+	clear_bit(devnode->minor, media_devnode_nums);
 	mutex_unlock(&media_devnode_lock);
 
 	put_device(&devnode->dev);