Crash with `pointer being freed was not allocated` in SNUnit

[lolgab]

I didn't try yet to reproduce on a smaller example.

Non-minimal reproduction

// server.sc
//> using platform "scala-native"
//> using lib "com.github.lolgab::snunit::0.2.4"
//> using lib "com.github.lolgab::snunit-async-epollcat::0.2.4"
//> using lib "com.armanbilge::epollcat::0.1.2"

import snunit._

AsyncServerBuilder
  .build(_.send(StatusCode.OK, "Hello!", Seq.empty))

#!/bin/bash

scala-cli package -f server.sc

curl --unix-socket /usr/local/var/run/unit/control.sock -XPUT -d '
{
  "applications": {
    "app": {
      "type": "external",
      "executable": "./server",
      "limits": {
        "requests": 2
      }
    }
  },
  "listeners": {
    "*:8082": {
      "pass": "applications/app"
    }
  }
}
' http://localhost/config

how to run

# in a terminal with pwd on the same dir where server.sc is
unitd --log /dev/stdout --no-daemon

# in another terminal
./deploy.sh

curl localhost:8082/hello
curl localhost:8082/hello
curl localhost:8082/hello

After the third request we receive the quit_t event from NGINX Unit which should make the process end gracefully and make Unit create a new one, but with epollcat I get this log in NGINX Unit:

server(68567,0x113118600) malloc: *** error for object 0x7f94df808200: pointer being freed was not allocated
server(68567,0x113118600) malloc: *** set a breakpoint in malloc_error_break to debug

And then it doesn't respond anymore.

The server behaves normally with scala-native-loop

[armanbilge]

This is the only call to free in epollcat.

epollcat/core/src/main/resources/scala-native/socket.c

Lines 63 to 64 in 911d61e

	if (address != NULL)
	free(converted_address);

So it's not really obvious to me what's going on :)