diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c
index 1e6db9cbe4dc518b0f0a482cf1c7e5eeffa0a3c4..1e9a404cee2bdbe0f5235d907484d365b54f3522 100644
--- a/kernel/trace/trace_hwlat.c
+++ b/kernel/trace/trace_hwlat.c
@@ -150,7 +150,7 @@ void trace_hwlat_callback(bool enter)
 		if (enter)
 			nmi_ts_start = time_get();
 		else
-			nmi_total_ts = time_get() - nmi_ts_start;
+			nmi_total_ts += time_get() - nmi_ts_start;
 	}
 
 	if (enter)