diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c
index fa95139445b28609b14544342ac6f4c88f3f56bd..a0251a78807dbe4f5b4a7c7aeacb63398fe0bbcf 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)