diff --git a/tools/testing/selftests/pidfd/Makefile b/tools/testing/selftests/pidfd/Makefile
index f4a2f28f926b..778b6cdc8aed 100644
--- a/tools/testing/selftests/pidfd/Makefile
+++ b/tools/testing/selftests/pidfd/Makefile
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
-CFLAGS += -g -I../../../../usr/include/ -pthread
+CFLAGS += -g -I../../../../usr/include/ -pthread -Wall
 
 TEST_GEN_PROGS := pidfd_test pidfd_fdinfo_test pidfd_open_test \
 	pidfd_poll_test pidfd_wait pidfd_getfd_test pidfd_setns_test
diff --git a/tools/testing/selftests/pidfd/pidfd_test.c b/tools/testing/selftests/pidfd/pidfd_test.c
index 9a2d64901d59..e2dd4ed84984 100644
--- a/tools/testing/selftests/pidfd/pidfd_test.c
+++ b/tools/testing/selftests/pidfd/pidfd_test.c
@@ -413,7 +413,7 @@ static void poll_pidfd(const char *test_name, int pidfd)
 
 	c = epoll_wait(epoll_fd, events, MAX_EVENTS, 5000);
 	if (c != 1 || !(events[0].events & EPOLLIN))
-		ksft_exit_fail_msg("%s test: Unexpected epoll_wait result (c=%d, events=%x) ",
+		ksft_exit_fail_msg("%s test: Unexpected epoll_wait result (c=%d, events=%x) "
 				   "(errno %d)\n",
 				   test_name, c, events[0].events, errno);
 
@@ -435,6 +435,8 @@ static int child_poll_exec_test(void *args)
 	 */
 	while (1)
 		sleep(1);
+
+	return 0;
 }
 
 static void test_pidfd_poll_exec(int use_waitpid)
diff --git a/tools/testing/selftests/pidfd/pidfd_wait.c b/tools/testing/selftests/pidfd/pidfd_wait.c
index 070c1c876df1..0dcb8365ddc3 100644
--- a/tools/testing/selftests/pidfd/pidfd_wait.c
+++ b/tools/testing/selftests/pidfd/pidfd_wait.c
@@ -95,20 +95,28 @@ TEST(wait_states)
 		.flags = CLONE_PIDFD | CLONE_PARENT_SETTID,
 		.exit_signal = SIGCHLD,
 	};
+	int pfd[2];
 	pid_t pid;
 	siginfo_t info = {
 		.si_signo = 0,
 	};
 
+	ASSERT_EQ(pipe(pfd), 0);
 	pid = sys_clone3(&args);
 	ASSERT_GE(pid, 0);
 
 	if (pid == 0) {
+		char buf[2];
+
+		close(pfd[1]);
 		kill(getpid(), SIGSTOP);
+		ASSERT_EQ(read(pfd[0], buf, 1), 1);
+		close(pfd[0]);
 		kill(getpid(), SIGSTOP);
 		exit(EXIT_SUCCESS);
 	}
 
+	close(pfd[0]);
 	ASSERT_EQ(sys_waitid(P_PIDFD, pidfd, &info, WSTOPPED, NULL), 0);
 	ASSERT_EQ(info.si_signo, SIGCHLD);
 	ASSERT_EQ(info.si_code, CLD_STOPPED);
@@ -117,6 +125,8 @@ TEST(wait_states)
 	ASSERT_EQ(sys_pidfd_send_signal(pidfd, SIGCONT, NULL, 0), 0);
 
 	ASSERT_EQ(sys_waitid(P_PIDFD, pidfd, &info, WCONTINUED, NULL), 0);
+	ASSERT_EQ(write(pfd[1], "C", 1), 1);
+	close(pfd[1]);
 	ASSERT_EQ(info.si_signo, SIGCHLD);
 	ASSERT_EQ(info.si_code, CLD_CONTINUED);
 	ASSERT_EQ(info.si_pid, parent_tid);
@@ -138,7 +148,7 @@ TEST(wait_states)
 
 TEST(wait_nonblock)
 {
-	int pidfd, status = 0;
+	int pidfd;
 	unsigned int flags = 0;
 	pid_t parent_tid = -1;
 	struct clone_args args = {