diff --git a/cont.c b/cont.c
index e345ac42c1c9cb..2b60860eddf9f9 100644
--- a/cont.c
+++ b/cont.c
@@ -2587,12 +2587,12 @@ rb_threadptr_root_fiber_release(rb_thread_t *th)
         /* ignore. A root fiber object will free th->ec */
     }
     else {
-        rb_execution_context_t *ec = GET_EC();
+        rb_execution_context_t *ec = rb_current_execution_context(false);
 
         VM_ASSERT(th->ec->fiber_ptr->cont.type == FIBER_CONTEXT);
         VM_ASSERT(th->ec->fiber_ptr->cont.self == 0);
 
-        if (th->ec == ec) {
+        if (ec && th->ec == ec) {
             rb_ractor_set_current_ec(th->ractor, NULL);
         }
         fiber_free(th->ec->fiber_ptr);
diff --git a/vm.c b/vm.c
index 633445957903ab..96f4189b14026c 100644
--- a/vm.c
+++ b/vm.c
@@ -3056,7 +3056,8 @@ ruby_vm_destruct(rb_vm_t *vm)
                 rb_objspace_free_objects(objspace);
                 rb_free_generic_iv_tbl_();
                 rb_free_default_rand_key();
-                if (th) {
+                if (th && vm->fork_gen == 0) {
+                    /* If we have forked, main_thread may not be the initial thread */
                     xfree(stack);
                     ruby_mimfree(th);
                 }