diff --git a/src/os/src/os_log.c b/src/os/src/os_log.c
index 138dad3..4d34d85 100644
--- a/src/os/src/os_log.c
+++ b/src/os/src/os_log.c
@@ -188,7 +188,7 @@ dds_set_log_mask(_In_ uint32_t cats)
 static void print_header(char *str)
 {
     int cnt;
-    char *tid, buf[MAX_TID_LEN] = { 0 };
+    char *tid, buf[MAX_TID_LEN+1] = { 0 };
     static const char fmt[] = "%10u.%06d/%*.*s:";
     os_time tv;
     unsigned sec;