From 33ab98f9e690b6505804a10b08e66fb366f9838b Mon Sep 17 00:00:00 2001
From: ko1 <ko1@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Fri, 11 Oct 2013 09:13:18 +0000
Subject: [PATCH] * ext/objspace/gc_hook.c: prohibit reentrant.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43253 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 ChangeLog              |  4 ++++
 ext/objspace/gc_hook.c | 33 ++++++++++++++++++++++++++++-----
 2 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 0809274fe0..009fe27845 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Fri Oct 11 18:12:47 2013  Koichi Sasada  <ko1@atdot.net>
+
+	* ext/objspace/gc_hook.c: prohibit reentrant.
+
 Fri Oct 11 18:11:34 2013  Koichi Sasada  <ko1@atdot.net>
 
 	* vm_trace.c (rb_postponed_job_flush): fix bit operation.
diff --git a/ext/objspace/gc_hook.c b/ext/objspace/gc_hook.c
index 7796eec61a..cf3dc0cc9d 100644
--- a/ext/objspace/gc_hook.c
+++ b/ext/objspace/gc_hook.c
@@ -16,19 +16,40 @@
 #include "ruby/ruby.h"
 #include "ruby/debug.h"
 
+static int invoking; /* TODO: should not be global variable */
+
+static VALUE
+invoke_proc_ensure(void *dmy)
+{
+    invoking = 0;
+    return Qnil;
+}
+
+static VALUE
+invoke_proc_begin(VALUE proc)
+{
+    return rb_proc_call(proc, rb_ary_new());
+}
+
 static void
 invoke_proc(void *data)
 {
     VALUE proc = (VALUE)data;
-    rb_proc_call(proc, rb_ary_new());
+    invoking += 1;
+    rb_ensure(invoke_proc_begin, proc, invoke_proc_ensure, 0);
 }
 
 static void
 gc_start_end_i(VALUE tpval, void *data)
 {
-    rb_trace_arg_t *tparg = rb_tracearg_from_tracepoint(tpval);
-    if (0) fprintf(stderr, "trace: %s\n", rb_tracearg_event_flag(tparg) == RUBY_INTERNAL_EVENT_GC_START ? "gc_start" : "gc_end");
-    rb_postponed_job_register(0, invoke_proc, data);
+    if (0) {
+	rb_trace_arg_t *tparg = rb_tracearg_from_tracepoint(tpval);
+	fprintf(stderr, "trace: %s\n", rb_tracearg_event_flag(tparg) == RUBY_INTERNAL_EVENT_GC_START ? "gc_start" : "gc_end");
+    }
+
+    if (invoking == 0) {
+	rb_postponed_job_register(0, invoke_proc, data);
+    }
 }
 
 static VALUE
@@ -38,7 +59,9 @@ set_gc_hook(VALUE rb_mObjSpace, VALUE proc, rb_event_flag_t event, const char *t
     ID tp_key = rb_intern(tp_str);
     ID proc_key = rb_intern(proc_str);
 
-    if (RTEST(tpval = rb_ivar_get(rb_mObjSpace, tp_key))) {
+    /* disable previous keys */
+    if (rb_ivar_defined(rb_mObjSpace, tp_key) != 0 &&
+	RTEST(tpval = rb_ivar_get(rb_mObjSpace, tp_key))) {
 	rb_tracepoint_disable(tpval);
 	rb_ivar_set(rb_mObjSpace, tp_key, Qnil);
 	rb_ivar_set(rb_mObjSpace, proc_key, Qnil);