# Rpc server session leak?

**URL:** <https://discuss.tvm.apache.org/t/rpc-server-session-leak/4827>\
**Category:** Development\
**Created:** [November 19, 2019, 1:11am UTC](https://discuss.tvm.apache.org/t/rpc-server-session-leak/4827 "2019-11-19T01:11:28Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![jmorrill](https://discuss.tvm.apache.org/user_avatar/discuss.tvm.apache.org/jmorrill/32/1023_2.png) [@jmorrill](https://discuss.tvm.apache.org/u/jmorrill)\
**Post date:** [November 19, 2019, 1:11am UTC](https://discuss.tvm.apache.org/t/rpc-server-session-leak/4827/1 "2019-11-19T01:11:28Z")

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To clarify, I do not think there is a problem with the software when used as currently designed. This is really only an issue with systems that cannot fork in rpc server.

I have added support for Windows to the [C++ RPC Server](https://github.com/apache/incubator-tvm/tree/master/apps/cpp_rpc), mostly by filling in the blanks. It’s not ready for PR or anything yet, but had a question.

tldr; _Does the RPC client have to make calls to free server side resources, or should the allocated resources be freed also when the connection is closed?_

Since there is no fork() on Windows, the RPC server and measurements are taken in process, like the current stub in the `rpc c++ server` source code here:

> <https://github.com/apache/incubator-tvm/blob/7efb72e6e8562a586f8551330d2bd79f946c34ab/apps/cpp_rpc/rpc_server.cc#L197>

The basic assumptions @FrozenGene uses makes sense: “If the ServerLoopProc does not finish by the timeout, forcefully close the connection, which in turn causes the internal RPC implementation to clean up and shutdown properly.”

I have noticed that when the timeout is hit though, .so files (dlls in my case) don’t get unloaded and GPU memory can leak. Inspection of `rpc_session.cc` and `rpc_module.cc` leads me to believe it is required for the client to send cleanup command codes (ex, `kDevFreeData`, `kModuleFree`, etc). If the server is closing the connection, it never gets the commands to free anything. In a situation where fork() is used (everywhere on Linux), there is not issue as the forked() server process just exits.

My work-around now, is to just remove the time-out functionality.

If this is true, would it be desirable to add some book-keeping in `rpc_session.cc` to track allocated resources, and free them on the rpc server’s session destructor?