[LTP] [PATCH v2 1/2] poll: add basic POLLHUP semantics test

[Jinseok Kim]

Add a basic poll() test to verify that POLLHUP is reported when the
peer end of a pipe is closed.

The test creates a pipe, closes the write end, and polls the read end
for POLLIN events. poll() is expected to return successfully and set
POLLHUP in revents.

This covers basic poll() lifecycle semantics that were not previously
tested.

Signed-off-by: Jinseok Kim <always.starving0@gmail.com>
---
 testcases/kernel/syscalls/poll/poll03.c | 62 +++++++++++++++++++++++++
 1 file changed, 62 insertions(+)
 create mode 100644 testcases/kernel/syscalls/poll/poll03.c

diff --git a/testcases/kernel/syscalls/poll/poll03.c b/testcases/kernel/syscalls/poll/poll03.c
new file mode 100644
index 000000000..da90b2945
--- /dev/null
+++ b/testcases/kernel/syscalls/poll/poll03.c
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2026 Jinseok Kim <always.starving0@gmail.com>
+ */
+
+/*\
+ * Check that poll() reports POLLHUP on a pipe read end
+ * after the write end has been closed.
+ */
+#include <unistd.h>
+#include <errno.h>
+#include <sys/poll.h>
+
+#include "tst_test.h"
+
+static int fds[2];
+
+void verify_pollhup(void)
+{
+	struct pollfd pfd = {
+		.fd = fds[0], .events = POLLIN,
+	};
+
+	SAFE_CLOSE(fds[1]);
+
+	TEST(poll(&pfd, 1, -1));
+
+	if (TST_RET == -1) {
+		tst_res(TFAIL | TTERRNO, "poll() failed");
+		return;
+	}
+
+	if (TST_RET != 1) {
+		tst_res(TFAIL, "Unexpected poll() return value %ld", TST_RET);
+		return;
+	}
+
+	TST_EXP_EXPR(pfd.revents & POLLHUP);
+	TST_EXP_EXPR((pfd.revents & ~POLLHUP) == 0);
+
+	tst_res(TPASS, "poll() reported POLLHUP");
+}
+
+static void setup(void)
+{
+	SAFE_PIPE(fds);
+}
+
+static void cleanup(void)
+{
+	if (fds[0] > 0)
+		SAFE_CLOSE(fds[0]);
+
+	if (fds[1] > 0)
+		SAFE_CLOSE(fds[1]);
+}
+
+static struct tst_test test = {
+	.setup = setup,
+	.cleanup = cleanup,
+	.test_all = verify_pollhup,
+};
--
2.43.0