In the Linux kernel, the following vulnerability has been resolved:
can: j1939: prevent deadlock by moving j1939_sk_errqueue()
This commit addresses a deadlock situation that can occur in certain scenarios, such as when running data TP/ETP transfer and subscribing to the error queue while receiving a net down event. The deadlock involves locks in the following order:
3 j1939_session_list_lock -> active_session_list_lock j1939_session_activate … j1939_sk_queue_activate_next -> sk_session_queue_lock … j1939_xtp_rx_eoma_one
2 j1939_sk_queue_drop_all -> sk_session_queue_lock … j1939_sk_netdev_event_netdown -> j1939_socks_lock j1939_netdev_notify
1 j1939_sk_errqueue -> j1939_socks_lock __j1939_session_cancel -> active_session_list_lock j1939_tp_rxtimer
CPU0 CPU1
---- ----
lock(&priv->active_session_list_lock); lock(&jsk->sk_session_queue_lock); lock(&priv->active_session_list_lock); lock(&priv->j1939_socks_lock);
The solution implemented in this commit is to move the j1939_sk_errqueue() call out of the active_session_list_lock context, thus preventing the deadlock situation.