Fix tracing.

Change-Id: If6837270baec694c00cc1884bae0f1842d49da75
diff --git a/runtime/trace.cc b/runtime/trace.cc
index a522e88..1a450c4 100644
--- a/runtime/trace.cc
+++ b/runtime/trace.cc
@@ -629,7 +629,7 @@
       overflow_ = true;
       return;
     }
-  } while (cur_offset_.CompareExchangeWeakSequentiallyConsistent(old_offset, new_offset) != 0);
+  } while (!cur_offset_.CompareExchangeWeakSequentiallyConsistent(old_offset, new_offset));
 
   TraceAction action = kTraceMethodEnter;
   switch (event) {