Code to trigger this problem:

```python
import multiprocessing as mp
from time import sleep


def wait_for_event(event):
    while not event.is_set():
        sleep(0.1)


def trigger_segment_fault():
    event = mp.get_context("fork").Event()
    p = mp.get_context("spawn").Process(target=wait_for_event, args=(event,))
    p.start()  # this will show the exitcode=-SIGSEGV
    sleep(1)
    print(p)
    event.set()
    p.terminate()


if __name__ == "__main__":
    trigger_segment_fault()
```

Accessing this forked event in a spawned process will result in a segment fault.

I have found a related report: https://bugs.python.org/issue43832. But I think it's not well documented in the Python 3 multiprocessing doc.

Will it be better to explicit indicate that the event is related to the start method context in the documentation?

Which python version and system are you seeing this on?

On 3.11 on a Mac I don't get a segfault but rather 

Process SpawnProcess-1:
Traceback (most recent call last):
  File "/Users/iritkatriel/src/cpython/Lib/multiprocessing/process.py", line 315, in _bootstrap
    self.run()
    ^^^^^^^^^^
  File "/Users/iritkatriel/src/cpython/Lib/multiprocessing/process.py", line 108, in run
    self._target(*self._args, **self._kwargs)
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/iritkatriel/src/cpython/tt.py", line 6, in wait_for_event
    while not event.is_set():
              ^^^^^^^^^^^^^^
  File "/Users/iritkatriel/src/cpython/Lib/multiprocessing/synchronize.py", line 328, in is_set
    with self._cond:
    ^^^^^^^^^^^^^^^^
  File "/Users/iritkatriel/src/cpython/Lib/multiprocessing/synchronize.py", line 230, in __enter__
    return self._lock.__enter__()
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/iritkatriel/src/cpython/Lib/multiprocessing/synchronize.py", line 95, in __enter__
    return self._semlock.__enter__()
           ^^^^^^^^^^^^^^^^^^^^^^^^^
OSError: [Errno 9] Bad file descriptor
<SpawnProcess name='SpawnProcess-1' pid=29612 parent=29610 stopped exitcode=1>