//
// Note that as soon as we're done with the fork there's no need to hold
// a lock any more because the parent won't do anything and the child is
- // in its own process. Thus the parent drops the lock guard while the child
- // forgets it to avoid unlocking it on a new thread, which would be invalid.
+ // in its own process. Thus the parent drops the lock guard immediately.
+ // The child calls `mem::forget` to leak the lock, which is crucial because
+ // releasing a lock is not async-signal-safe.
let env_lock = sys::os::env_read_lock();
let (pid, pidfd) = unsafe { self.do_fork()? };
if pid == 0 {
crate::panic::always_abort();
- mem::forget(env_lock);
+ mem::forget(env_lock); // avoid non-async-signal-safe unlocking
drop(input);
let Err(err) = unsafe { self.do_exec(theirs, envp.as_ref()) };
let errno = err.raw_os_error().unwrap_or(libc::EINVAL) as u32;