diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index 0c8ecf0..0cd4215 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -541,10 +541,17 @@ static int __event__synthesize_thread(union perf_event *comm_event,
 						      tgid, process, machine) < 0)
 			return -1;
 
+		/*
+		 * send mmap only for thread group leader
+		 * see thread__init_map_groups
+		 */
+		if (pid == tgid &&
+		    perf_event__synthesize_mmap_events(tool, mmap_event, pid, tgid,
+						       process, machine, mmap_data,
+						       proc_map_timeout))
+			return -1;
 
-		return perf_event__synthesize_mmap_events(tool, mmap_event, pid, tgid,
-							  process, machine, mmap_data,
-							  proc_map_timeout);
+		return 0;
 	}
 
 	if (machine__is_default_guest(machine))