[LTP] [PATCH v2 6/8] syscalls: Add epoll_wait11

[Cyril Hrubis]

A test that checks that EPOLLHUP is generated properly when a pipe is
closed while epoll_wait() waits on the read end of a pipe.

Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
---
 runtest/syscalls                              |  1 +
 .../kernel/syscalls/epoll_wait/.gitignore     |  1 +
 .../kernel/syscalls/epoll_wait/epoll_wait11.c | 94 +++++++++++++++++++
 3 files changed, 96 insertions(+)
 create mode 100644 testcases/kernel/syscalls/epoll_wait/epoll_wait11.c

diff --git a/runtest/syscalls b/runtest/syscalls
index 3fd61b814..c16cf3554 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -199,6 +199,7 @@ epoll_wait07 epoll_wait07
 epoll_wait08 epoll_wait08
 epoll_wait09 epoll_wait09
 epoll_wait10 epoll_wait10
+epoll_wait11 epoll_wait11
 
 epoll_pwait01 epoll_pwait01
 epoll_pwait02 epoll_pwait02
diff --git a/testcases/kernel/syscalls/epoll_wait/.gitignore b/testcases/kernel/syscalls/epoll_wait/.gitignore
index 30139375d..57bdf0806 100644
--- a/testcases/kernel/syscalls/epoll_wait/.gitignore
+++ b/testcases/kernel/syscalls/epoll_wait/.gitignore
@@ -8,3 +8,4 @@ epoll_wait07
 epoll_wait08
 epoll_wait09
 epoll_wait10
+epoll_wait11
diff --git a/testcases/kernel/syscalls/epoll_wait/epoll_wait11.c b/testcases/kernel/syscalls/epoll_wait/epoll_wait11.c
new file mode 100644
index 000000000..764fe5f61
--- /dev/null
+++ b/testcases/kernel/syscalls/epoll_wait/epoll_wait11.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2026 Cyril Hrubis <chrubis@suse.cz>
+ */
+
+/*\
+ * Verify that epoll_wait reports EPOLLHUP when the write end of a pipe is
+ * closed while a child process is blocked in epoll_wait.
+ *
+ * [Algorithm]
+ *
+ * - Create a pipe and register the read end with an epoll instance for
+ *   EPOLLIN.
+ * - Fork a child that blocks in epoll_wait on the pipe read end.
+ * - Parent waits for the child to enter sleep state, then closes the write
+ *   end.
+ * - The child's epoll_wait should return with EPOLLHUP and the child reports
+ *   the result via its exit code.
+ */
+
+#include <sys/epoll.h>
+
+#include "tst_test.h"
+#include "tst_epoll.h"
+
+static int efd = -1, fds[2] = {-1, -1};
+
+static void run(void)
+{
+	pid_t pid;
+
+	SAFE_PIPE(fds);
+
+	efd = SAFE_EPOLL_CREATE1(0);
+
+	struct epoll_event ev = {
+		.events = EPOLLIN,
+		.data.fd = fds[0],
+	};
+
+	SAFE_EPOLL_CTL(efd, EPOLL_CTL_ADD, fds[0], &ev);
+
+	pid = SAFE_FORK();
+	if (!pid) {
+		SAFE_CLOSE(fds[1]);
+
+		TEST(epoll_wait(efd, &ev, 1, 5000));
+		if (TST_RET != 1) {
+			tst_res(TFAIL | TTERRNO,
+				"epoll_wait() returned %li, expected 1",
+				TST_RET);
+			exit(0);
+		}
+
+		if (ev.data.fd != fds[0]) {
+			tst_res(TFAIL, "epoll.data.fd %d, expected %d",
+				ev.data.fd, fds[0]);
+			exit(0);
+		}
+
+		if (!(ev.events & EPOLLHUP)) {
+			tst_res(TFAIL, "events %x, EPOLLHUP not set",
+				ev.events);
+			exit(0);
+		}
+
+		tst_res(TPASS,
+			"epoll_wait() reported EPOLLHUP on pipe hangup");
+		exit(0);
+	}
+
+	TST_PROCESS_STATE_WAIT(pid, 'S', 0);
+	SAFE_CLOSE(fds[1]);
+	SAFE_CLOSE(fds[0]);
+	SAFE_CLOSE(efd);
+}
+
+static void cleanup(void)
+{
+	if (fds[1] != -1)
+		SAFE_CLOSE(fds[1]);
+
+	if (fds[0] != -1)
+		SAFE_CLOSE(fds[0]);
+
+	if (efd != -1)
+		SAFE_CLOSE(efd);
+}
+
+static struct tst_test test = {
+	.test_all = run,
+	.cleanup = cleanup,
+	.forks_child = 1,
+};
-- 
2.52.0