1 files changed, 9 insertions, 0 deletions
diff --git a/thread.c b/thread.c
index c600a8763b..f2dd417297 100644
--- a/thread.c
+++ b/thread.c
@@ -777,6 +777,11 @@ thread_do_start(rb_thread_t *th)
 
 void rb_ec_clear_current_thread_trace_func(const rb_execution_context_t *ec);
 
+// io.c
+VALUE rb_io_prep_stdin(void);
+VALUE rb_io_prep_stdout(void);
+VALUE rb_io_prep_stderr(void);
+
 static int
 thread_start_func_2(rb_thread_t *th, VALUE *stack_start)
 {
@@ -799,6 +804,10 @@ thread_start_func_2(rb_thread_t *th, VALUE *stack_start)
         RB_VM_LOCK();
         {
             rb_vm_ractor_blocking_cnt_dec(th->vm, th->ractor, __FILE__, __LINE__);
+            rb_ractor_t *r = th->ractor;
+            r->r_stdin = rb_io_prep_stdin();
+            r->r_stdout = rb_io_prep_stdout();
+            r->r_stderr = rb_io_prep_stderr();
         }
         RB_VM_UNLOCK();
     }