# Bug report

### Bug description:

On Linux `proc.wait()` does not return after `proc.kill()` when there as sub/sub processes.
This only happens when the standard streams are piped, it looks like `wait()` blocks until the pipes are closed.

```python
import asyncio
import os
import time
async def main():
    proc = await asyncio.create_subprocess_exec(
        "/usr/bin/python3", "-c", "import os;os.system('sleep 20')",
        stdout=asyncio.subprocess.PIPE,
        stderr=asyncio.subprocess.PIPE)
    
    time.sleep(1)
    os.system("ps -f --forest --format pid,ppid,pgid,sid,comm")

    print(f">> This python proces pid={os.getpid()} has a `python3` child process, which has a `sleep` child process.")
    print(f">> Kill the `python3` child process pid={proc.pid}")
    proc.kill()

    os.system("ps -f --forest --format pid,ppid,pgid,sid,comm")
    print(f">> The `python3` child process was killed, the `sleep` process gets orfaned.")
    print(f">> Calling `proc.wait()` or `proc.communicate()` does not return until `sleep` process exits.")
    
    await proc.wait()

asyncio.run(main())
```

I don't know if it's a documentation issue or a bug.

- It would be more intuitive that `proc.wait()` after a `proc.kill()` returned when the process exited, and does not depend on other processes completion.
- It would be more intuitive to use have the same behavior when standard streams are piped and when they are not.



### CPython versions tested on:

3.11

### Operating systems tested on:

Linux
asyncio `proc.kill()` and `proc.wait()` are counter intuitive
This is a GitHub Issue
repo:cpython
owner:python
Title : asyncio `proc.kill()` and `proc.wait()` are counter intuitive
Issue date:

--- start body ---
# Bug report

### Bug description:

On Linux `proc.wait()` does not return after `proc.kill()` when there as sub/sub processes.
This only happens when the standard streams are piped, it looks like `wait()` blocks until the pipes are closed.

```python
import asyncio
import os
import time
async def main():
    proc = await asyncio.create_subprocess_exec(
        "/usr/bin/python3", "-c", "import os;os.system('sleep 20')",
        stdout=asyncio.subprocess.PIPE,
        stderr=asyncio.subprocess.PIPE)
    
    time.sleep(1)
    os.system("ps -f --forest --format pid,ppid,pgid,sid,comm")

    print(f">> This python proces pid={os.getpid()} has a `python3` child process, which has a `sleep` child process.")
    print(f">> Kill the `python3` child process pid={proc.pid}")
    proc.kill()

    os.system("ps -f --forest --format pid,ppid,pgid,sid,comm")
    print(f">> The `python3` child process was killed, the `sleep` process gets orfaned.")
    print(f">> Calling `proc.wait()` or `proc.communicate()` does not return until `sleep` process exits.")
    
    await proc.wait()

asyncio.run(main())
```

I don't know if it's a documentation issue or a bug.

- It would be more intuitive that `proc.wait()` after a `proc.kill()` returned when the process exited, and does not depend on other processes completion.
- It would be more intuitive to use have the same behavior when standard streams are piped and when they are not.



### CPython versions tested on:

3.11

### Operating systems tested on:

Linux
--- end body ---

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