No output prints when debugging app in linux docker container from macOS

Type: Debugger

• OS and Version: macOS 11.2.1
• VS Code Version: 1.53.2
• C/C++ Extension Version: 1.2.2

VSCode runs on Mac, C++ application runs on a linux container (Ubuntu) with gdbserver, gdb used to debug is also taken from the linux container.

I'm able to debug, I can step over, step into, continue, set breakpoints, everything works OK, except I do not see any output print (std::cout) done by the application. I do not see anything in the DEBUG CONSOLE (as indicated in #3968) besides the gdb traces; I do not see any external console (I'm setting "externalConsole" to "true"), even after doing the work around explained here to force the first appearance of the terminal (if I just run this Open Terminal task, yes, a terminal appears). I've also enabled logging ("logging": { "engineLogging": true, "trace": true, "traceResponse": true }), which just prints more debug traces but not the C++ application prints.

launch.json

{
	"version": "0.2.0",
	"configurations": [
	{
			"name": "C++ Launch (GDBSERVER)",
			"type": "cppdbg",
			"request": "launch",
			"miDebuggerServerAddress": "localhost:2000",
			"preLaunchTask": "start-gdbserver",
			"miDebuggerPath": "${workspaceRoot}/docker_wrapper_gdb.sh",
			"targetArchitecture": "x64",
			"program": "${workspaceRoot}/src/lr/bin/lr.bin",
			"args": [],
			"stopAtEntry": true,
			"externalConsole": true,
			"cwd": "${workspaceRoot}",
			"sourceFileMap":{
				"${workspaceRoot}": "${workspaceRoot}"
			},
			"environment": [],
			"logging": {
				"trace": true,
				"traceResponse": true,
				"engineLogging": true
			}
	}
 ]
}

Note: docker_wrapper_gdb.sh is just a script to call the gdb from the linux container.

tasks.json

{
            "label": "start-gdbserver",
            "type": "shell",
            "command": "docker exec -d devenv gdbserver :2000 ./src/lr/bin/lr.bin",
            "problemMatcher": []
        }

Start by reproducing the remote debugging setup described in launch.json and tasks.json, including docker_wrapper_gdb.sh, with the C++ app running under gdbserver. Trace how application stdout is routed for externalConsole and the DEBUG CONSOLE; done means std::cout output is visible during this macOS-to-Linux-container session without breaking existing debugging controls.