diff --git a/tools/perf/builtin-timechart.c b/tools/perf/builtin-timechart.c
index 4079062d25b0..37bf1eb0755f 100644
--- a/tools/perf/builtin-timechart.c
+++ b/tools/perf/builtin-timechart.c
@@ -242,7 +242,7 @@ static void pid_fork(struct timechart *tchart, int pid, int ppid, u64 timestamp)
 		pid_set_comm(tchart, pid, pp->current->comm);
 
 	p->start_time = timestamp;
-	if (p->current) {
+	if (p->current && !p->current->start_time) {
 		p->current->start_time = timestamp;
 		p->current->state_since = timestamp;
 	}