selftests/pidfd: add fifth PIDFD_INFO_EXIT selftest

Add a selftest for PIDFD_INFO_EXIT behavior.

Link: https://lore.kernel.org/r/20250305-work-pidfs-kill_on_last_close-v3-14-c8c3d8361705@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/tools/testing/selftests/pidfd/pidfd_info_test.c b/tools/testing/selftests/pidfd/pidfd_info_test.c
index 0d0af4c2a84dca1798665b5aa714bf02215393dd..16e4be2364df2ee8f4386e5d1be4250d2d2d16ac 100644 (file)
--- a/tools/testing/selftests/pidfd/pidfd_info_test.c
+++ b/tools/testing/selftests/pidfd/pidfd_info_test.c
@@ -195,4 +195,27 @@ TEST_F(pidfd_info, success_reaped)
        ASSERT_EQ(WEXITSTATUS(info.exit_code), 0);
 }
 
+TEST_F(pidfd_info, success_reaped_poll)
+{
+       struct pidfd_info info = {
+               .mask = PIDFD_INFO_CGROUPID | PIDFD_INFO_EXIT,
+       };
+       struct pollfd fds = {};
+       int nevents;
+
+       fds.events = POLLIN;
+       fds.fd = self->child_pidfd2;
+
+       nevents = poll(&fds, 1, -1);
+       ASSERT_EQ(nevents, 1);
+       ASSERT_TRUE(!!(fds.revents & POLLIN));
+       ASSERT_TRUE(!!(fds.revents & POLLHUP));
+
+       ASSERT_EQ(ioctl(self->child_pidfd2, PIDFD_GET_INFO, &info), 0);
+       ASSERT_FALSE(!!(info.mask & PIDFD_INFO_CREDS));
+       ASSERT_TRUE(!!(info.mask & PIDFD_INFO_EXIT));
+       ASSERT_TRUE(WIFSIGNALED(info.exit_code));
+       ASSERT_EQ(WTERMSIG(info.exit_code), SIGKILL);
+}
+
 TEST_HARNESS_MAIN