* gc.c (rb_gc_mark_locations): get rid of underflow.

* gc.c (mark_current_machine_context): check if the main thread stack
  position may shink under the intialized position.  [ruby-core:16436]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@16072 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 3 insertions, 3 deletions

diff --git a/gc.c b/gc.c
index edcd9b099b..1a826fbc54 100644
--- a/gc.c
+++ b/gc.c
@@ -794,6 +794,7 @@ rb_gc_mark_locations(VALUE *start, VALUE *end)
 {
     long n;
 
+    if (end <= start) return;
     n = end - start;
     mark_locations_array(start,n);
 }
@@ -1491,10 +1492,9 @@ mark_current_machine_context(rb_thread_t *th)
     mark_locations_array((VALUE*)save_regs_gc_mark,
 			 sizeof(save_regs_gc_mark) / sizeof(VALUE));
 
-    mark_locations_array(stack_start, stack_end - stack_start);
+    rb_gc_mark_locations(stack_start, stack_end);
 #ifdef __ia64
-    mark_locations_array(th->machine_register_stack_start,
-			 th->machine_register_stack_end - th->machine_register_stack_start);
+    rb_gc_mark_locations(th->machine_register_stack_start, th->machine_register_stack_end);
 #endif
 #if defined(__human68k__) || defined(__mc68000__)
     mark_locations_array((VALUE*)((char*)STACK_END + 2),