[PATCH v1 5/9] can: j1939: transport: make sure the aborted session will be deactivated only once

[Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>]

j1939_session_cancel() was modifying session->state without protecting
it by locks and without checking actual state of the session.

This patch moves j1939_tp_set_rxtimeout() into j1939_session_cancel()
and adds the missing locking.

Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")
Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
---
 net/can/j1939/transport.c | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c
index e5f1a56994c6..ecdedfc0b10c 100644
--- a/net/can/j1939/transport.c
+++ b/net/can/j1939/transport.c
@@ -1042,12 +1042,13 @@ j1939_session_deactivate_activate_next(struct j1939_session *session)
 		j1939_sk_queue_activate_next(session);
 }
 
-static void j1939_session_cancel(struct j1939_session *session,
+static void __j1939_session_cancel(struct j1939_session *session,
 				 enum j1939_xtp_abort err)
 {
 	struct j1939_priv *priv = session->priv;
 
 	WARN_ON_ONCE(!err);
+	lockdep_assert_held(&session->priv->active_session_list_lock);
 
 	session->err = j1939_xtp_abort_to_errno(priv, err);
 	/* do not send aborts on incoming broadcasts */
@@ -1062,6 +1063,20 @@ static void j1939_session_cancel(struct j1939_session *session,
 		j1939_sk_send_loop_abort(session->sk, session->err);
 }
 
+static void j1939_session_cancel(struct j1939_session *session,
+				 enum j1939_xtp_abort err)
+{
+	j1939_session_list_lock(session->priv);
+
+	if (session->state >= J1939_SESSION_ACTIVE &&
+	    session->state < J1939_SESSION_WAITING_ABORT) {
+		j1939_tp_set_rxtimeout(session, J1939_XTP_ABORT_TIMEOUT_MS);
+		__j1939_session_cancel(session, err);
+	}
+
+	j1939_session_list_unlock(session->priv);
+}
+
 static enum hrtimer_restart j1939_tp_txtimer(struct hrtimer *hrtimer)
 {
 	struct j1939_session *session =
@@ -1108,8 +1123,6 @@ static enum hrtimer_restart j1939_tp_txtimer(struct hrtimer *hrtimer)
 		netdev_alert(priv->ndev, "%s: 0x%p: tx aborted with unknown reason: %i\n",
 			     __func__, session, ret);
 		if (session->skcb.addr.type != J1939_SIMPLE) {
-			j1939_tp_set_rxtimeout(session,
-					       J1939_XTP_ABORT_TIMEOUT_MS);
 			j1939_session_cancel(session, J1939_XTP_ABORT_OTHER);
 		} else {
 			session->err = ret;
@@ -1169,7 +1182,7 @@ static enum hrtimer_restart j1939_tp_rxtimer(struct hrtimer *hrtimer)
 			hrtimer_start(&session->rxtimer,
 				      ms_to_ktime(J1939_XTP_ABORT_TIMEOUT_MS),
 				      HRTIMER_MODE_REL_SOFT);
-			j1939_session_cancel(session, J1939_XTP_ABORT_TIMEOUT);
+			__j1939_session_cancel(session, J1939_XTP_ABORT_TIMEOUT);
 		}
 		j1939_session_list_unlock(session->priv);
 	}
@@ -1375,7 +1388,6 @@ j1939_xtp_rx_cts_one(struct j1939_session *session, struct sk_buff *skb)
 
  out_session_cancel:
 	j1939_session_timers_cancel(session);
-	j1939_tp_set_rxtimeout(session, J1939_XTP_ABORT_TIMEOUT_MS);
 	j1939_session_cancel(session, err);
 }
 
@@ -1572,7 +1584,6 @@ static int j1939_xtp_rx_rts_session_active(struct j1939_session *session,
 
 		/* RTS on active session */
 		j1939_session_timers_cancel(session);
-		j1939_tp_set_rxtimeout(session, J1939_XTP_ABORT_TIMEOUT_MS);
 		j1939_session_cancel(session, J1939_XTP_ABORT_BUSY);
 	}
 
@@ -1583,7 +1594,6 @@ static int j1939_xtp_rx_rts_session_active(struct j1939_session *session,
 			     session->last_cmd);
 
 		j1939_session_timers_cancel(session);
-		j1939_tp_set_rxtimeout(session, J1939_XTP_ABORT_TIMEOUT_MS);
 		j1939_session_cancel(session, J1939_XTP_ABORT_BUSY);
 
 		return -EBUSY;
@@ -1785,7 +1795,6 @@ static void j1939_xtp_rx_dat_one(struct j1939_session *session,
 
  out_session_cancel:
 	j1939_session_timers_cancel(session);
-	j1939_tp_set_rxtimeout(session, J1939_XTP_ABORT_TIMEOUT_MS);
 	j1939_session_cancel(session, J1939_XTP_ABORT_FAULT);
 	j1939_session_put(session);
 }
-- 
2.24.0.rc1