[PATCH] firmware: arm_scmi: Fix NULL dereference on notify error path

[Cristian Marussi]

Since commit b5daf93b809d1 ("firmware: arm_scmi: Avoid notifier
registration for unsupported events") the call chains leading to the helper
__scmi_event_handler_get_ops expect an ERR_PTR to be returned on failure to
get an handler for the requested event key, while the current helper can
still return a NULL when no handler could be found or created.

Fix by forcing an ERR_PTR return value when the handler reference is NULL.

Fixes: b5daf93b809d1 ("firmware: arm_scmi: Avoid notifier registration for unsupported events")
Signed-off-by: Cristian Marussi <cristian.marussi at arm.com>
---
 drivers/firmware/arm_scmi/notify.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/arm_scmi/notify.c b/drivers/firmware/arm_scmi/notify.c
index 9168794adae4..40ec184eedae 100644
--- a/drivers/firmware/arm_scmi/notify.c
+++ b/drivers/firmware/arm_scmi/notify.c
@@ -1066,7 +1066,7 @@ static int scmi_register_event_handler(struct scmi_notify_instance *ni,
  * since at creation time we usually want to have all setup and ready before
  * events really start flowing.
  *
- * Return: A properly refcounted handler on Success, NULL on Failure
+ * Return: A properly refcounted handler on Success, ERR_PTR on Failure
  */
 static inline struct scmi_event_handler *
 __scmi_event_handler_get_ops(struct scmi_notify_instance *ni,
@@ -1113,7 +1113,7 @@ __scmi_event_handler_get_ops(struct scmi_notify_instance *ni,
 	}
 	mutex_unlock(&ni->pending_mtx);
 
-	return hndl;
+	return hndl ?: ERR_PTR(-ENODEV);
 }
 
 static struct scmi_event_handler *
-- 
2.53.0