From: Hans Verkuil <hverkuil-cisco@xs4all.nl> stable inclusion from stable-v6.6.34 commit 77c4cd7e0b38f5d950ef7adbae64442aefec5ecf category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IAD6H2 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- 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> Signed-off-by: Wang Hai <wanghai38@huawei.com> --- 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 680fbb3a9340..94abd042045d 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: -- 2.17.1