[CENNSO-1443] fix: do not crash when timer expires on deleted session (…

…#374)

upf/upf_pfcp_server.c

@@ -516,6 +516,11 @@ request_t1_expired (u32 seq_no)
   ASSERT (req->flags.is_stopped == 0);
   req->timer = ~0;
 
+  // handle edge case: timer expired in this iteration
+  // TODO: this should not be needed after multithreading
+  if (!req->data)
+    return;
+
   upf_debug ("Msg Seq No: %u, %p, n1 %u\n", req->seq_no, req, req->n1);
 
   /* make sure to resent reports to new peer if smfset peer is changed */
@@ -537,10 +542,10 @@ request_t1_expired (u32 seq_no)
       return;
     }
 
+  u8 type = pfcp_msg_type (req->data);
+
   if (--req->n1 != 0)
     {
-      u8 type = pfcp_msg_type (req->data);
-
       /*
          FIXME: here in pool_is_free_index we check for node index which can be
          reused as soon as node goes back. Instead we should stop all requests
@@ -568,7 +573,6 @@ request_t1_expired (u32 seq_no)
     }
   else
     {
-      u8 type = pfcp_msg_type (req->data);
       u32 node = req->node;
 
       upf_debug ("abort...\n");