Correctly handle `Process.fork` with an active `Fiber.scheduler`. (#15385)

In the child process, nullify the current fiber scheduler and set the current fiber to blocking.

1 files changed, 1 insertions, 0 deletions

diff --git a/thread.c b/thread.c
index 6e5c8e89ff..5f592a4256 100644
--- a/thread.c
+++ b/thread.c
@@ -4997,6 +4997,7 @@ rb_thread_atfork(void)
     rb_threadptr_pending_interrupt_clear(th);
     rb_thread_atfork_internal(th, terminate_atfork_i);
     th->join_list = NULL;
+    th->scheduler = Qnil;
     rb_fiber_atfork(th);
 
     /* We don't want reproduce CVE-2003-0900. */