* gc.c (mark_mem_region): Use the Valgrind API only to mark

the type field as accessible, not the whole object that
we are checking. Marking the whole object accessible hides
uninitialized field bugs!

* lib.c: And found a bug already: lazy_str was not completely
initializing all of the object fields (ls.prefix, ls.list)
before invoking memory allocating operations, making it
possible for the garbage collector to encounter uninitialized
object areas.

3 files changed, 17 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index 2c819949..5cb9f923 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,18 @@
 2011-11-18  Kaz Kylheku  <kaz@kylheku.com>
 
+	* gc.c (mark_mem_region): Use the Valgrind API only to mark
+	the type field as accessible, not the whole object that
+	we are checking. Marking the whole object accessible hides
+	uninitialized field bugs!
+
+	* lib.c: And found a bug already: lazy_str was not completely
+	initializing all of the object fields (ls.prefix, ls.list)
+	before invoking memory allocating operations, making it
+	possible for the garbage collector to encounter uninitialized
+	object areas.
+
+2011-11-18  Kaz Kylheku  <kaz@kylheku.com>
+
 	Added a JSON parsing test case. This flushed out a bug which crashed
 	the garbage collector (uninitialized fields in function objects).
 
diff --git a/gc.c b/gc.c
index 8f1ee6dc..1f31cf54 100644
--- a/gc.c
+++ b/gc.c
@@ -331,7 +331,7 @@ static void mark_mem_region(val *low, val *high)
     if (in_heap(maybe_obj)) {
 #ifdef HAVE_VALGRIND
       if (opt_vg_debug)
-        VALGRIND_MAKE_MEM_DEFINED(maybe_obj, sizeof *maybe_obj);
+        VALGRIND_MAKE_MEM_DEFINED(&maybe_obj->t.type, sizeof maybe_obj->t.type);
 #endif
       type_t t = maybe_obj->t.type;
       if ((t & FREE) == 0) {
diff --git a/lib.c b/lib.c
index 41bf5e8f..f1079030 100644
--- a/lib.c
+++ b/lib.c
@@ -1853,7 +1853,9 @@ val lazy_str(val lst, val term, val limit)
 {
   val obj = make_obj();
   obj->ls.type = LSTR;
-  obj->ls.opts = nil; /* Must init before calling something that can gc! */
+
+  /* Must init before calling something that can gc! */
+  obj->ls.opts = obj->ls.list = obj->ls.prefix = nil;
 
   term = or2(term, string(L"\n"));