diff --git a/tools/testing/selftests/mount_setattr/mount_setattr_test.c b/tools/testing/selftests/mount_setattr/mount_setattr_test.c
index c6a8c732b802..304e6422a1f1 100644
--- a/tools/testing/selftests/mount_setattr/mount_setattr_test.c
+++ b/tools/testing/selftests/mount_setattr/mount_setattr_test.c
@@ -1026,7 +1026,7 @@ FIXTURE_SETUP(mount_setattr_idmapped)
 			"size=100000,mode=700"), 0);
 
 	ASSERT_EQ(mount("testing", "/mnt", "tmpfs", MS_NOATIME | MS_NODEV,
-			"size=100000,mode=700"), 0);
+			"size=2m,mode=700"), 0);
 
 	ASSERT_EQ(mkdir("/mnt/A", 0777), 0);