diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index b3b398cc461..d7721d593d2 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2016-01-22  Yao Qi  <yao.qi@linaro.org>
+
+	PR testsuite/19491
+	* gdb.base/multi-forks.c: Include
+	../lib/unbuffer_output.c
+	(main): Call gdb_unbuffer_output.
+
 2016-01-21  Doug Evans  <dje@google.com>
 
 	* lib/ada.exp (gdb_compile_ada): Fix typo.
diff --git a/gdb/testsuite/gdb.base/multi-forks.c b/gdb/testsuite/gdb.base/multi-forks.c
index 994d0c7f8dc..06579c8eb39 100644
--- a/gdb/testsuite/gdb.base/multi-forks.c
+++ b/gdb/testsuite/gdb.base/multi-forks.c
@@ -20,6 +20,8 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+#include "../lib/unbuffer_output.c"
+
 pid_t pids[4];
 
 int
@@ -27,6 +29,8 @@ main()
 {
   int i;
 
+  gdb_unbuffer_output ();
+
   for (i = 0; i < 4; i++)
     pids [i] = fork ();