diff --git a/trace.c b/trace.c
index 54aaee5818..b6f25a23fd 100644
--- a/trace.c
+++ b/trace.c
@@ -216,7 +216,7 @@ void trace_argv_printf(const char **argv, const char *format, ...)
 	va_end(ap);
 }
 
-void trace_strbuf(const char *key, const struct strbuf *data)
+void trace_strbuf(struct trace_key *key, const struct strbuf *data)
 {
 	trace_strbuf_fl(NULL, 0, key, data);
 }