[GitHub] [incubator-nuttx] xiaoxiang781216 commented on a change in pull request #5252: net/tcp/tcp_send*: reliably obtain the TCP connection pointer in TCP event handlers

[GitBox <gi...@apache.org>]

xiaoxiang781216 commented on a change in pull request #5252:
URL: https://github.com/apache/incubator-nuttx/pull/5252#discussion_r802281137



##########
File path: net/tcp/tcp_send_buffered.c
##########
@@ -355,10 +355,39 @@ static uint16_t psock_send_eventhandler(FAR struct net_driver_s *dev,
                                         FAR void *pvconn, FAR void *pvpriv,
                                         uint16_t flags)
 {
-  FAR struct tcp_conn_s *conn = (FAR struct tcp_conn_s *)pvconn;
+  /* FAR struct tcp_conn_s *conn = (FAR struct tcp_conn_s *)pvconn;
+   *
+   * Do not use pvconn argument to get the TCP connection pointer (the above
+   * commented line) because pvconn is normally NULL for some events like
+   * NETDEV_DOWN. Instead, the TCP connection pointer can be reliably
+   * obtained from the corresponding TCP socket.
+   */
+
   FAR struct socket *psock = (FAR struct socket *)pvpriv;
+  FAR struct tcp_conn_s *conn;
   bool rexmit = false;
 
+  DEBUGASSERT(psock != NULL);
+
+  /* Get the TCP connection pointer reliably from
+   * the corresponding TCP socket.
+   */
+
+  conn = psock->s_conn;
+  DEBUGASSERT(conn != NULL);
+
+  /* The TCP socket is connected and, hence, should be bound to a device.
+   * Make sure that the polling device is the one that we are bound to.
+   */
+
+  DEBUGASSERT(conn->dev != NULL);

Review comment:
       If so, you should review #5434 which fix the potential crash in this case.




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