How to find the cause of crash?

[zhmt via Digitalmars-d-learn]

I developed a socks5 proxy server with vibe.d.
but it crashed after running a few minutes, with the output below:
Task terminated with uncaught exception: Operating on closed 
TCPConnection.
Task terminated with uncaught exception: Operating on closed 
TCPConnection.
Task terminated with unhandled exception:
./run: line 3: 49999 段错误               (core dumped) ./ezsock


the ./run is a simple shell to start ./ezsock.


Now , my question is:
How to get the position it crashes?
Or get the method call stack?

Any help is welcome,Thanks in advance!!