eval_intern.h: refine stack overflow detection

* eval_intern.h (TH_PUSH_TAG, TH_EXEC_TAG): refine stack overflow
  detection.  chain local tag after setjmp() successed on it, because
  calling setjmp() also can overflow the stack.
  [ruby-dev:47804] [Bug #9109]
* vm_eval.c (rb_catch_obj): now th->tag points previous tag until
  TH_EXEC_TAG().


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43707 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 1 insertions, 1 deletions

diff --git a/vm_eval.c b/vm_eval.c
index bace6bbbcf..24bac12bbf 100644
--- a/vm_eval.c
+++ b/vm_eval.c
@@ -1823,7 +1823,7 @@ rb_catch_obj(VALUE t, VALUE (*func)(), VALUE data)
 
     TH_PUSH_TAG(th);
 
-    th->tag->tag = tag;
+    _tag.tag = tag;
 
     if ((state = TH_EXEC_TAG()) == 0) {
 	/* call with argc=1, argv = [tag], block = Qnil to insure compatibility */