[PATCH 15/22] selftests/coredump: fix userspace coredump client detection

[Christian Brauner]

PIDFD_INFO_COREDUMP is only retrievable until the task has exited. After
it has exited task->mm is NULL. So if the task didn't actually coredump
we can't retrieve it's dumpability settings anymore. Only if the task
did coredump will we have stashed the coredump information in the
respective struct pid.

Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
---
 tools/testing/selftests/coredump/coredump_socket_test.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/coredump/coredump_socket_test.c b/tools/testing/selftests/coredump/coredump_socket_test.c
index 658f3966064f..5103d9f13003 100644
--- a/tools/testing/selftests/coredump/coredump_socket_test.c
+++ b/tools/testing/selftests/coredump/coredump_socket_test.c
@@ -271,22 +271,26 @@ TEST_F(coredump, socket_detect_userspace_client)
 			_exit(EXIT_FAILURE);
 
 		close(fd_socket);
+		pause();
 		_exit(EXIT_SUCCESS);
 	}
 
 	pidfd = sys_pidfd_open(pid, 0);
 	ASSERT_GE(pidfd, 0);
 
-	waitpid(pid, &status, 0);
-	ASSERT_TRUE(WIFEXITED(status));
-	ASSERT_EQ(WEXITSTATUS(status), 0);
-
 	ASSERT_TRUE(get_pidfd_info(pidfd, &info));
 	ASSERT_GT((info.mask & PIDFD_INFO_COREDUMP), 0);
 	ASSERT_EQ((info.coredump_mask & PIDFD_COREDUMPED), 0);
 
 	wait_and_check_coredump_server(pid_coredump_server, _metadata, self);
 
+	ASSERT_EQ(sys_pidfd_send_signal(pidfd, SIGKILL, NULL, 0), 0);
+	ASSERT_EQ(close(pidfd), 0);
+
+	waitpid(pid, &status, 0);
+	ASSERT_TRUE(WIFSIGNALED(status));
+	ASSERT_EQ(WTERMSIG(status), SIGKILL);
+
 	ASSERT_NE(stat("/tmp/coredump.file", &st), 0);
 	ASSERT_EQ(errno, ENOENT);
 }

-- 
2.47.3