diff --git a/pkg/sentry/kernel/thread_group.go b/pkg/sentry/kernel/thread_group.go
index 4fce5e916..4dbf10f0c 100644
--- a/pkg/sentry/kernel/thread_group.go
+++ b/pkg/sentry/kernel/thread_group.go
@@ -376,7 +376,12 @@ func (tg *ThreadGroup) SetControllingTTY(tty *TTY, steal bool, isReadable bool)
 
 	// "The calling process must be a session leader and not have a
 	// controlling terminal already." - tty_ioctl(4)
-	if tg.processGroup.session.leader != tg || tg.tty != nil {
+	if tg.processGroup.session.leader != tg {
+		return linuxerr.EINVAL
+	}
+	if tg.tty == tty {
+		return nil
+	} else if tg.tty != nil {
 		return linuxerr.EINVAL
 	}
 
diff --git a/test/syscalls/linux/pty.cc b/test/syscalls/linux/pty.cc
index 132d71ac6..b7e8494c4 100644
--- a/test/syscalls/linux/pty.cc
+++ b/test/syscalls/linux/pty.cc
@@ -1476,6 +1476,8 @@ TEST_F(JobControlTest, SetTTY) {
   auto res = RunInChild([=]() {
     TEST_PCHECK(setsid() >= 0);
     TEST_PCHECK(ioctl(!replica_.get(), TIOCSCTTY, 0));
+    // The second attempt setting the same terminal has to be no-op.
+    TEST_PCHECK(ioctl(!replica_.get(), TIOCSCTTY, 0));
   });
   ASSERT_NO_ERRNO(res);
 }