diff --git a/tools/perf/util/mem-events.c b/tools/perf/util/mem-events.c
index de981ddcd1d3ec6aafd7767af73f5d625200d159..eadb83d163673537af2a7e87522b20d58e9ad7ae 100644
--- a/tools/perf/util/mem-events.c
+++ b/tools/perf/util/mem-events.c
@@ -221,18 +221,20 @@ int perf_mem__snp_scnprintf(char *out, size_t sz, struct mem_info *mem_info)
 	return l;
 }
 
-void perf_mem__lck_scnprintf(char *out, size_t sz __maybe_unused,
-			     struct mem_info *mem_info)
+int perf_mem__lck_scnprintf(char *out, size_t sz, struct mem_info *mem_info)
 {
 	u64 mask = PERF_MEM_LOCK_NA;
+	int l;
 
 	if (mem_info)
 		mask = mem_info->data_src.mem_lock;
 
 	if (mask & PERF_MEM_LOCK_NA)
-		strncat(out, "N/A", 3);
+		l = scnprintf(out, sz, "N/A");
 	else if (mask & PERF_MEM_LOCK_LOCKED)
-		strncat(out, "Yes", 3);
+		l = scnprintf(out, sz, "Yes");
 	else
-		strncat(out, "No", 2);
+		l = scnprintf(out, sz, "No");
+
+	return l;
 }
diff --git a/tools/perf/util/mem-events.h b/tools/perf/util/mem-events.h
index 84c79a452f80e32b7afcb5a88ec989ee46cf7d5f..87c44ff75dc8434e8a15a3bd9930c6e5eb4d9e98 100644
--- a/tools/perf/util/mem-events.h
+++ b/tools/perf/util/mem-events.h
@@ -28,6 +28,6 @@ struct mem_info;
 int perf_mem__tlb_scnprintf(char *out, size_t sz, struct mem_info *mem_info);
 int perf_mem__lvl_scnprintf(char *out, size_t sz, struct mem_info *mem_info);
 int perf_mem__snp_scnprintf(char *out, size_t sz, struct mem_info *mem_info);
-void perf_mem__lck_scnprintf(char *out, size_t sz, struct mem_info *mem_info);
+int perf_mem__lck_scnprintf(char *out, size_t sz, struct mem_info *mem_info);
 
 #endif /* __PERF_MEM_EVENTS_H */