From 797d7efde18c5f7acf5264047842fd974f383ca9 Mon Sep 17 00:00:00 2001
From: Takashi Kokubun <takashikkbn@gmail.com>
Date: Wed, 29 May 2019 08:56:26 +0900
Subject: [PATCH] Prevent MJIT compilation from running while moving

pointers.

Instead of 4fe908c1643c3f355edd787bb651aefb53b996c0, just locking the MJIT
worker may be fine for this case. And also we might have the same issue
in all `gc_compact_after_gc` calls.
---
 gc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/gc.c b/gc.c
index cd784ef6bbd2b0..6f518b7079fa30 100644
--- a/gc.c
+++ b/gc.c
@@ -8272,6 +8272,8 @@ gc_compact_after_gc(rb_objspace_t *objspace, int use_toward_empty, int use_doubl
 {
     if (0) fprintf(stderr, "gc_compact_after_gc: %d,%d,%d\n", use_toward_empty, use_double_pages, use_verifier);
 
+    mjit_gc_start_hook(); // prevent MJIT from running while moving pointers related to ISeq
+
     if (use_verifier) {
         gc_verify_internal_consistency(Qnil);
     }
@@ -8315,6 +8317,8 @@ gc_compact_after_gc(rb_objspace_t *objspace, int use_toward_empty, int use_doubl
     (void)moved_list;
 #endif
 
+    mjit_gc_exit_hook(); // unlock MJIT here, because `rb_gc()` calls `mjit_gc_start_hook()` again.
+
     /* GC after compaction to eliminate T_MOVED */
     rb_gc();
 }