From 2ec7838967aec9d43d44c2d53377e827d6fcf041 Mon Sep 17 00:00:00 2001
From: Damien George <damien.p.george@gmail.com>
Date: Wed, 27 Mar 2019 16:00:25 +1100
Subject: [PATCH] extmod/modlwip: Handle case of accept callback called with
 null PCB.

---
 extmod/modlwip.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/extmod/modlwip.c b/extmod/modlwip.c
index d1359a2aa4..6960546f68 100644
--- a/extmod/modlwip.c
+++ b/extmod/modlwip.c
@@ -429,6 +429,11 @@ STATIC err_t _lwip_tcp_accept_finished(void *arg, struct tcp_pcb *pcb)
 
 // Callback for incoming tcp connections.
 STATIC err_t _lwip_tcp_accept(void *arg, struct tcp_pcb *newpcb, err_t err) {
+    // err can be ERR_MEM to notify us that there was no memory for an incoming connection
+    if (err != ERR_OK) {
+        return ERR_OK;
+    }
+
     lwip_socket_obj_t *socket = (lwip_socket_obj_t*)arg;
     tcp_recv(newpcb, _lwip_tcp_recv_unaccepted);