From: s.wanabe@...
Date: 2019-05-15T23:41:23+00:00
Subject: [ruby-core:92674] [Ruby trunk Bug#15809] GC.verify_compaction_references - intermittent SEGV's on multiple platforms

Issue #15809 has been updated by wanabe (_ wanabe).


gc_update_references() updates finalizer_table after https://git.ruby-lang.org/ruby.git/commit/?id=3cf767ee.
Therefore, "[BUG] ROOT finalizers points to MOVED" error seems to be suppressed.

I guess the [BUG] of [ruby-core:92665]  is caused by T_IMEMO env, not by finalizer_table.
Values of `env->env[]` are pinned normally, but finalizer can create imemo_env objects and they have unpinned `env->env[]` as I said in [ruby-core:92615].

```
diff --git a/gc.c b/gc.c
index b71c501a5b..ec90416672 100644
--- a/gc.c
+++ b/gc.c
@@ -7721,7 +7721,12 @@ gc_ref_update_imemo(rb_objspace_t *objspace, VALUE obj)
         case imemo_env:
             {
                 rb_env_t *env = (rb_env_t *)obj;
+                VALUE *envp = (VALUE*)env->env;
+                unsigned int i;
                 TYPED_UPDATE_IF_MOVED(objspace, rb_iseq_t *, env->iseq);
+                for (i = 0; i < env->env_size; i++) {
+                    UPDATE_IF_MOVED(objspace, envp[i]);
+                }
             }
             break;
             break;
```

----------------------------------------
Bug #15809: GC.verify_compaction_references - intermittent SEGV's on multiple platforms
https://bugs.ruby-lang.org/issues/15809#change-78037

* Author: MSP-Greg (Greg L)
* Status: Assigned
* Priority: Normal
* Assignee: tenderlovemaking (Aaron Patterson)
* Target version: 
* ruby -v: ruby 2.7.0dev (2019-05-06 trunk c3cf1ef9bb) [x64-mingw32
* Backport: 2.4: UNKNOWN, 2.5: UNKNOWN, 2.6: UNKNOWN
----------------------------------------
See

https://travis-ci.org/ruby/ruby/jobs/525627187#L2684
https://ci.appveyor.com/project/ruby/ruby/builds/24138134/job/i7e441u7se11w7ey#L3402

Both have an error similar to:
```
/ruby/test/ruby/test_gc_compact.rb:128: [BUG] ROOT finalizers points to MOVED:
  0x0000000004679c20 -> 0x00000000089367c0 [0     ] T_ARRAY [E ] len: 1 (embed)
```

ruby-loco has also failed with a similar error.  Attached STDERR output.

---Files--------------------------------
test_all_err.log (42 KB)


-- 
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