backport r24713 which adds a check for freelist exhaustion in gc_swee…

…p; this prevents segfaults from certain tight loops. An example test case: Time.now while true

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8_6@25871 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,7 @@
+Thu Nov 19 2:44:00 2009 Kirk Haines <khaines@ruby-lang.org>
+
+	* gc.c: backport r24713 which adds a check for freelist exhaustion in gc_sweep; this prevents segfaults from certain tight loops. An example test case: Time.now while true
+
 Fri Aug 28 12:54:00 2009 Kirk Haines <khaines@ruby-lang.org>
 
 	* Backport #1524 [ruby-core:23567]; lib/ostrct.rb (OpenStruct@new_ostruct_member): check if it's; also a little code cleanup to do a few things more efficiently. Tests adjusted accordingly.

gc.c

@@ -1183,7 +1183,15 @@ gc_sweep()
     /* clear finalization list */
     if (final_list) {
 	deferred_final_list = final_list;
-	rb_thread_pending = 1;
+        if (!freelist && !rb_thread_critical) {
+          rb_gc_finalize_deferred();
+        }
+        else {
+	  rb_thread_pending = 1;
+        }
+        if (!freelist) {
+          add_heap();
+        }
 	return;
     }
     free_unused_heaps();