diff --git a/sys/kern/tty_pts.c b/sys/kern/tty_pts.c
--- a/sys/kern/tty_pts.c
+++ b/sys/kern/tty_pts.c
@@ -271,12 +271,7 @@
 		return (0);
 	case FIONREAD:
 		tty_lock(tp);
-		if (psc->pts_flags & PTS_FINISHED) {
-			/* Force read() to be called. */
-			*(int *)data = 1;
-		} else {
-			*(int *)data = ttydisc_getc_poll(tp);
-		}
+		*(int *)data = ttydisc_getc_poll(tp);
 		tty_unlock(tp);
 		return (0);
 	case FIODGNAME:
diff --git a/tests/sys/kern/Makefile b/tests/sys/kern/Makefile
--- a/tests/sys/kern/Makefile
+++ b/tests/sys/kern/Makefile
@@ -39,6 +39,7 @@
 PLAIN_TESTS_C+=	subr_unit_test
 ATF_TESTS_C+=	sysctl_kern_proc
 ATF_TESTS_C+=	sys_getrandom
+ATF_TESTS_C+=	tty_pts
 ATF_TESTS_C+=	unix_dgram
 ATF_TESTS_C+=	unix_passfd_dgram
 TEST_METADATA.unix_passfd_dgram+=	is_exclusive="true"
@@ -87,6 +88,8 @@
 CFLAGS.mqueue_test+=	-I${SRCTOP}/tests
 LIBADD.mqueue_test+=	rt
 
+LIBADD.tty_pts+=	atf_c util
+
 ATF_TESTS_C+=	libkern_crc32
 SRCS.libkern_crc32+=	libkern_crc32.c
 .PATH: ${SRCTOP}/sys/libkern
diff --git a/tests/sys/kern/tty_pts.c b/tests/sys/kern/tty_pts.c
new file mode 100644
--- /dev/null
+++ b/tests/sys/kern/tty_pts.c
@@ -0,0 +1,64 @@
+/*-
+ * Copyright (c) 2024 Kyle Evans <kevans@FreeBSD.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <sys/types.h>
+#include <sys/ioctl.h>
+
+#include <termios.h>
+
+#include <atf-c.h>
+#include <libutil.h>
+
+/* Just a little more concise. */
+#define	newpty(masterp, slavep)	openpty((masterp), (slavep), NULL, NULL, NULL)
+
+ATF_TC_WITHOUT_HEAD(fionread);
+ATF_TC_BODY(fionread, tc)
+{
+	char rbuf[32];
+	char buf[] = "Hello";
+	int master, slave;
+	int bytes;
+
+	ATF_REQUIRE_EQ(0, newpty(&master, &slave));
+
+	/* Should be empty to begin with. */
+	ATF_REQUIRE_EQ(0, ioctl(master, FIONREAD, &bytes));
+	ATF_REQUIRE_EQ(0, bytes);
+
+	ATF_REQUIRE_EQ(sizeof(buf) - 1, write(slave, buf, sizeof(buf) - 1));
+	ATF_REQUIRE_EQ(0, ioctl(master, FIONREAD, &bytes));
+	ATF_REQUIRE_EQ(sizeof(buf) - 1, bytes);
+
+	/* Drain what we have available, should result in 0 bytes again. */
+	ATF_REQUIRE_EQ(sizeof(buf) - 1, read(master, rbuf, sizeof(rbuf)));
+	ATF_REQUIRE_EQ(0, ioctl(master, FIONREAD, &bytes));
+	ATF_REQUIRE_EQ(0, bytes);
+
+	/*
+	 * Write once more, then close the slave side with data still in the
+	 * buffer.
+	 */
+	ATF_REQUIRE_EQ(sizeof(buf) - 1, write(slave, buf, sizeof(buf) - 1));
+	ATF_REQUIRE_EQ(0, ioctl(master, FIONREAD, &bytes));
+	ATF_REQUIRE_EQ(sizeof(buf) - 1, bytes);
+
+	ATF_REQUIRE_EQ(0, close(slave));
+
+	/*
+	 * The tty's output queue is discarded upon close, so we shouldn't have
+	 * anything else to read().
+	 */
+	ATF_REQUIRE_EQ(0, ioctl(master, FIONREAD, &bytes));
+	ATF_REQUIRE_EQ(0, bytes);
+	ATF_REQUIRE_EQ(0, read(master, rbuf, sizeof(rbuf)));
+}
+
+ATF_TP_ADD_TCS(tp)
+{
+	ATF_TP_ADD_TC(tp, fionread);
+	return (atf_no_error());
+}