media: cadence: csi2rx: Unregister v4l2 async notifier

The notifier is added to the global notifier list when registered. When
the module is removed, the struct csi2rx_priv in which the notifier is
embedded, is destroyed. As a result the notifier list has a reference to
a notifier that no longer exists. This causes invalid memory accesses
when the list is iterated over. Similar for when the probe fails.
Unregister and clean up the notifier to avoid this.

Fixes: 1fc3b37f34f6 ("media: v4l: cadence: Add Cadence MIPI-CSI2 RX driver")

Signed-off-by: Pratyush Yadav <[email protected]>
Tested-by: Julien Massot <[email protected]>
Reviewed-by: Laurent Pinchart <[email protected]>
Reviewed-by: Tomi Valkeinen <[email protected]>
Reviewed-by: Maxime Ripard <[email protected]>
Signed-off-by: Jai Luthra <[email protected]>
Signed-off-by: Sakari Ailus <[email protected]>
Signed-off-by: Hans Verkuil <[email protected]>

1 files changed, 6 insertions, 1 deletions

diff --git a/drivers/media/platform/cadence/cdns-csi2rx.c b/drivers/media/platform/cadence/cdns-csi2rx.c
index b9d9058e2ce3..64e472ca3594 100644
--- a/drivers/media/platform/cadence/cdns-csi2rx.c
+++ b/drivers/media/platform/cadence/cdns-csi2rx.c
@@ -479,8 +479,10 @@ static int csi2rx_parse_dt(struct csi2rx_priv *csi2rx)
 	asd = v4l2_async_nf_add_fwnode_remote(&csi2rx->notifier, fwh,
 					      struct v4l2_async_connection);
 	of_node_put(ep);
-	if (IS_ERR(asd))
+	if (IS_ERR(asd)) {
+		v4l2_async_nf_cleanup(&csi2rx->notifier);
 		return PTR_ERR(asd);
+	}
 
 	csi2rx->notifier.ops = &csi2rx_notifier_ops;
 
@@ -543,6 +545,7 @@ static int csi2rx_probe(struct platform_device *pdev)
 	return 0;
 
 err_cleanup:
+	v4l2_async_nf_unregister(&csi2rx->notifier);
 	v4l2_async_nf_cleanup(&csi2rx->notifier);
 err_free_priv:
 	kfree(csi2rx);
@@ -553,6 +556,8 @@ static void csi2rx_remove(struct platform_device *pdev)
 {
 	struct csi2rx_priv *csi2rx = platform_get_drvdata(pdev);
 
+	v4l2_async_nf_unregister(&csi2rx->notifier);
+	v4l2_async_nf_cleanup(&csi2rx->notifier);
 	v4l2_async_unregister_subdev(&csi2rx->subdev);
 	kfree(csi2rx);
 }