usb: typec: ucsi: Fix NULL pointer access

commit b13abcb7ddd8d38de769486db5bd917537b32ab1 upstream.

Resources should be released only after all threads that utilize them
have been destroyed.
This commit ensures that resources are not released prematurely by waiting
for the associated workqueue to complete before deallocating them.

Cc: stable <[email protected]>
Fixes: b9aa02c ("usb: typec: ucsi: Add polling mechanism for partner tasks like alt mode checking")
Signed-off-by: Andrei Kuchynski <[email protected]>
Reviewed-by: Heikki Krogerus <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Andrei Kuchynski

drivers/usb/typec/ucsi/ucsi.c

@@ -1313,11 +1313,11 @@ static int ucsi_init(struct ucsi *ucsi)
 
 err_unregister:
 	for (con = connector; con->port; con++) {
+		if (con->wq)
+			destroy_workqueue(con->wq);
 		ucsi_unregister_partner(con);
 		ucsi_unregister_altmodes(con, UCSI_RECIPIENT_CON);
 		ucsi_unregister_port_psy(con);
-		if (con->wq)
-			destroy_workqueue(con->wq);
 		typec_unregister_port(con->port);
 		con->port = NULL;
 	}
@@ -1479,10 +1479,6 @@ void ucsi_unregister(struct ucsi *ucsi)
 
 	for (i = 0; i < ucsi->cap.num_connectors; i++) {
 		cancel_work_sync(&ucsi->connector[i].work);
-		ucsi_unregister_partner(&ucsi->connector[i]);
-		ucsi_unregister_altmodes(&ucsi->connector[i],
-					 UCSI_RECIPIENT_CON);
-		ucsi_unregister_port_psy(&ucsi->connector[i]);
 
 		if (ucsi->connector[i].wq) {
 			struct ucsi_work *uwork;
@@ -1497,6 +1493,11 @@ void ucsi_unregister(struct ucsi *ucsi)
 			mutex_unlock(&ucsi->connector[i].lock);
 			destroy_workqueue(ucsi->connector[i].wq);
 		}
+
+		ucsi_unregister_partner(&ucsi->connector[i]);
+		ucsi_unregister_altmodes(&ucsi->connector[i],
+					 UCSI_RECIPIENT_CON);
+		ucsi_unregister_port_psy(&ucsi->connector[i]);
 		typec_unregister_port(ucsi->connector[i].port);
 	}