can: j1939: warn if resources are still linked on destroy

j1939_session_destroy() and __j1939_priv_release() should be called only if session, ecu or socket are not linked or used by any one else. If at least one of these resources is linked, then the reference counting is broken somewhere. This warning will be triggered before KASAN will do, and will make it easier to debug initial issue. This works on platforms without KASAN support. Signed-off-by: Oleksij Rempel <[email protected]>
vieko · Nov 13, 2019 · 4a15d57 · 4a15d57
1 parent ddeeb7d
commit 4a15d57
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diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c
@@ -152,6 +152,10 @@ static void __j1939_priv_release(struct kref *kref)
 
 	netdev_dbg(priv->ndev, "%s: 0x%p\n", __func__, priv);
 
+	WARN_ON_ONCE(!list_empty(&priv->active_session_list));
+	WARN_ON_ONCE(!list_empty(&priv->ecus));
+	WARN_ON_ONCE(!list_empty(&priv->j1939_socks));
+
 	dev_put(ndev);
 	kfree(priv);
 }

diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c
@@ -267,6 +267,9 @@ static void j1939_session_destroy(struct j1939_session *session)
 
 	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
 
+	WARN_ON_ONCE(!list_empty(&session->sk_session_queue_entry));
+	WARN_ON_ONCE(!list_empty(&session->active_session_list_entry));
+
 	skb_queue_purge(&session->skb_queue);
 	__j1939_session_drop(session);
 	j1939_priv_put(session->priv);