On Fri Jul 17 15:42:46 2026 +0200, Hans Verkuil wrote:
> If device_register fails, then we are supposed to call put_device.
> Explain why we do not do that.
>
> Reviewed-by: Laurent Pinchart <[email protected]>
> Signed-off-by: Hans Verkuil <[email protected]>
Patch committed.
Thanks,
Hans Verkuil
drivers/media/v4l2-core/v4l2-dev.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
---
diff --git a/drivers/media/v4l2-core/v4l2-dev.c
b/drivers/media/v4l2-core/v4l2-dev.c
index d750bf10febe..fd267fb74905 100644
--- a/drivers/media/v4l2-core/v4l2-dev.c
+++ b/drivers/media/v4l2-core/v4l2-dev.c
@@ -1075,6 +1075,20 @@ int __video_register_device(struct video_device *vdev,
mutex_lock(&videodev_lock);
ret = device_register(&vdev->dev);
if (ret < 0) {
+ /*
+ * We should do a put_device() here, but the problem is that
+ * the V4L2 API expects drivers to call video_device_release()
+ * on error, and so both put_device() and video_device_release
+ * would kfree vdev.
+ *
+ * The proper solution would be to split this function into
+ * two parts: initialization and registration, and then rework
+ * all drivers.
+ *
+ * Until then just skip the put_device and free everything.
+ * This will result in a small memory leak, which is better
+ * than a double-free.
+ */
mutex_unlock(&videodev_lock);
pr_err("%s: device_register failed\n", __func__);
goto cleanup;
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