Bug 973571 - Do not allow gcparam to set the mark stack limit while a gc is in progress; r=billm

--HG--
extra : rebase_source : 620edcc859a86d8cb6e7d525de4079238a89a07e

js/src/builtin/TestingFunctions.cpp

@@ -320,6 +320,11 @@ GCParameter(JSContext *cx, unsigned argc, Value *vp)
         return false;
     }
 
+    if (param == JSGC_MARK_STACK_LIMIT && IsIncrementalGCInProgress(cx->runtime())) {
+        JS_ReportError(cx, "attempt to set markStackLimit while a GC is in progress");
+        return false;
+    }
+
     if (param == JSGC_MAX_BYTES) {
         uint32_t gcBytes = JS_GetGCParameter(cx->runtime(), JSGC_BYTES);
         if (value < gcBytes) {