diff --git a/run-command.c b/run-command.c
index 1b821042b4..ec2c12e98b 100644
--- a/run-command.c
+++ b/run-command.c
@@ -1753,7 +1753,8 @@ void run_processes_parallel(const struct run_process_parallel_opts *opts)
 
 	if (do_trace2)
 		trace2_region_enter_printf(tr2_category, tr2_label, NULL,
-					   "max:%d", opts->processes);
+					   "max:%"PRIuMAX,
+					   (uintmax_t)opts->processes);
 
 	pp_init(&pp, opts, &pp_sig);
 	while (1) {
diff --git a/trace2.h b/trace2.h
index 1f0669bbd2..19e04bf040 100644
--- a/trace2.h
+++ b/trace2.h
@@ -390,6 +390,7 @@ void trace2_region_enter_printf_va_fl(const char *file, int line,
 	trace2_region_enter_printf_va_fl(__FILE__, __LINE__, (category), \
 					 (label), (repo), (fmt), (ap))
 
+__attribute__((format (printf, 6, 7)))
 void trace2_region_enter_printf_fl(const char *file, int line,
 				   const char *category, const char *label,
 				   const struct repository *repo,