[PATCH] fix GC issue on rb_global_variable array

[PATCH] fix GC issue on rb_global_variable array

[Xuanzhong Wei]

We need to add the array to ruby's global_list right after created it;
otherwise it probably gets GCed.
---
 ext/unicorn_http/unicorn_http.rl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ext/unicorn_http/unicorn_http.rl b/ext/unicorn_http/unicorn_http.rl
index 6fc3498..357440b 100644
--- a/ext/unicorn_http/unicorn_http.rl
+++ b/ext/unicorn_http/unicorn_http.rl
@@ -921,6 +921,7 @@ void Init_unicorn_http(void)
   VALUE mUnicorn, cHttpParser;
 
   mark_ary = rb_ary_new();
+  rb_global_variable(&mark_ary);
   mUnicorn = rb_define_module("Unicorn");
   cHttpParser = rb_define_class_under(mUnicorn, "HttpParser", rb_cObject);
   eHttpParserError =
@@ -976,7 +977,6 @@ void Init_unicorn_http(void)
   init_unicorn_httpdate(mark_ary);
 
   OBJ_FREEZE(mark_ary);
-  rb_global_variable(&mark_ary);
 
 #ifndef HAVE_RB_HASH_CLEAR
   id_clear = rb_intern("clear");
-- 
2.14.1

Re: [PATCH] fix GC issue on rb_global_variable array

[Eric Wong]

Xuanzhong Wei <azrlew@gmail.com> wrote:
> diff --git a/ext/unicorn_http/unicorn_http.rl b/ext/unicorn_http/unicorn_http.rl
> index 6fc3498..357440b 100644
> --- a/ext/unicorn_http/unicorn_http.rl
> +++ b/ext/unicorn_http/unicorn_http.rl
> @@ -921,6 +921,7 @@ void Init_unicorn_http(void)
>    VALUE mUnicorn, cHttpParser;
>  
>    mark_ary = rb_ary_new();
> +  rb_global_variable(&mark_ary);
>    mUnicorn = rb_define_module("Unicorn");
>    cHttpParser = rb_define_class_under(mUnicorn, "HttpParser", rb_cObject);
>    eHttpParserError =
> @@ -976,7 +977,6 @@ void Init_unicorn_http(void)
>    init_unicorn_httpdate(mark_ary);
>  
>    OBJ_FREEZE(mark_ary);
> -  rb_global_variable(&mark_ary);

Yes, the compiler should be free to drop mark_ary by here, since
it only needs its address (not the actual VALUE) and OBJ_FREEZE
only accesses the RBasic->flags field if init_unicorn_httpdate
gets inlined.

Pushed to master as e85de00a3065461f6fac466276d915b809f40c7c.
Also, created a 5.3-stable branch for 5.3.1 (to be released today)
@ git://bogomips.org/unicorn

Re: [PATCH] fix GC issue on rb_global_variable array

[Xuanzhong Wei]

Really appreciate your help!