diff --git a/airscan-trace.c b/airscan-trace.c
index f23a59d..98a6306 100644
--- a/airscan-trace.c
+++ b/airscan-trace.c
@@ -110,10 +110,8 @@ trace_open (const char *device_name)
     path = str_append(path, ".log");
     t->log = fopen(path, "w");
 
-    // work around gcc 11 warning
-    log_assert(NULL, str_len(path) >= 4);
-
-    strcpy(path + str_len(path) - 4, ".tar");
+    path = str_resize(path, str_len(path) - 4);
+    path = str_append(path, ".tar");
     t->data = fopen(path, "wb");
 
     mem_free(path);