should not free local hook_list here.

exec_hooks_postcheck() clean executed hook_list if it is needed.
list_exec is freed if there are no events and this list is local
event (connected to specific iseq). However, iseq keeps to point
this local hook_list, freed list. To prevent this situation,
do not free hook_list here even if it has no events.

This issue is reported by @joker1007.
https://twitter.com/joker1007/status/1153649170797830144

1 files changed, 0 insertions, 3 deletions

diff --git a/vm_trace.c b/vm_trace.c
index da68a0a8de..ac7550d7e9 100644
--- a/vm_trace.c
+++ b/vm_trace.c
@@ -198,9 +198,6 @@ clean_hooks(const rb_execution_context_t *ec, rb_hook_list_t *list)
     }
     else {
         /* local events */
-        if (list->events == 0) {
-            ruby_xfree(list);
-        }
     }
 }