diff --git a/tools/testing/selftests/namespaces/listns_efault_test.c b/tools/testing/selftests/namespaces/listns_efault_test.c
index b570746e917c..26b452c98c66 100644
--- a/tools/testing/selftests/namespaces/listns_efault_test.c
+++ b/tools/testing/selftests/namespaces/listns_efault_test.c
@@ -38,7 +38,7 @@ TEST(listns_partial_fault_with_ns_cleanup)
 	__u64 *ns_ids;
 	ssize_t ret;
 	long page_size;
-	pid_t pid, iter_pid;
+	pid_t pid, iter_pid, ns_pids[5];
 	int pidfds[5];
 	int sv[5][2];
 	int iter_pidfd;
@@ -114,6 +114,7 @@ TEST(listns_partial_fault_with_ns_cleanup)
 
 		pid = create_child(&pidfds[i], CLONE_NEWNS);
 		ASSERT_NE(pid, -1);
+		ns_pids[i] = pid;
 
 		if (pid == 0) {
 			close(sv[i][0]); /* Close parent end */
@@ -164,7 +165,7 @@ TEST(listns_partial_fault_with_ns_cleanup)
 
 	/* Wait for all mount namespace children to exit and cleanup */
 	for (i = 0; i < 5; i++) {
-		waitpid(-1, NULL, 0);
+		waitpid(ns_pids[i], NULL, 0);
 		close(sv[i][0]);
 		close(pidfds[i]);
 	}
@@ -175,6 +176,12 @@ TEST(listns_partial_fault_with_ns_cleanup)
 	ASSERT_EQ(ret, iter_pid);
 	close(iter_pidfd);
 
+	/* If listns() is not supported the iterator exits cleanly via ENOSYS */
+	if (WIFEXITED(status) && WEXITSTATUS(status) == PIDFD_SKIP) {
+		munmap(map, page_size);
+		SKIP(return, "listns() not supported");
+	}
+
 	/* Should have been killed */
 	ASSERT_TRUE(WIFSIGNALED(status));
 	ASSERT_EQ(WTERMSIG(status), SIGKILL);
@@ -250,7 +257,7 @@ TEST(listns_late_fault_with_ns_cleanup)
 	__u64 *ns_ids;
 	ssize_t ret;
 	long page_size;
-	pid_t pid, iter_pid;
+	pid_t pid, iter_pid, ns_pids[10];
 	int pidfds[10];
 	int sv[10][2];
 	int iter_pidfd;
@@ -320,6 +327,7 @@ TEST(listns_late_fault_with_ns_cleanup)
 
 		pid = create_child(&pidfds[i], CLONE_NEWNS);
 		ASSERT_NE(pid, -1);
+		ns_pids[i] = pid;
 
 		if (pid == 0) {
 			close(sv[i][0]); /* Close parent end */
@@ -373,7 +381,7 @@ TEST(listns_late_fault_with_ns_cleanup)
 
 	/* Wait for all children and cleanup */
 	for (i = 0; i < 10; i++) {
-		waitpid(-1, NULL, 0);
+		waitpid(ns_pids[i], NULL, 0);
 		close(sv[i][0]);
 		close(pidfds[i]);
 	}
@@ -384,6 +392,12 @@ TEST(listns_late_fault_with_ns_cleanup)
 	ASSERT_EQ(ret, iter_pid);
 	close(iter_pidfd);
 
+	/* If listns() is not supported the iterator exits cleanly via ENOSYS */
+	if (WIFEXITED(status) && WEXITSTATUS(status) == PIDFD_SKIP) {
+		munmap(map, page_size);
+		SKIP(return, "listns() not supported");
+	}
+
 	/* Should have been killed */
 	ASSERT_TRUE(WIFSIGNALED(status));
 	ASSERT_EQ(WTERMSIG(status), SIGKILL);
@@ -402,7 +416,7 @@ TEST(listns_mnt_ns_cleanup_on_fault)
 	__u64 *ns_ids;
 	ssize_t ret;
 	long page_size;
-	pid_t pid, iter_pid;
+	pid_t pid, iter_pid, ns_pids[8];
 	int pidfds[8];
 	int sv[8][2];
 	int iter_pidfd;
@@ -462,6 +476,7 @@ TEST(listns_mnt_ns_cleanup_on_fault)
 
 		pid = create_child(&pidfds[i], CLONE_NEWNS);
 		ASSERT_NE(pid, -1);
+		ns_pids[i] = pid;
 
 		if (pid == 0) {
 			close(sv[i][0]); /* Close parent end */
@@ -508,7 +523,7 @@ TEST(listns_mnt_ns_cleanup_on_fault)
 
 	/* Wait for children and cleanup */
 	for (i = 0; i < 8; i++) {
-		waitpid(-1, NULL, 0);
+		waitpid(ns_pids[i], NULL, 0);
 		close(sv[i][0]);
 		close(pidfds[i]);
 	}
@@ -519,6 +534,12 @@ TEST(listns_mnt_ns_cleanup_on_fault)
 	ASSERT_EQ(ret, iter_pid);
 	close(iter_pidfd);
 
+	/* If listns() is not supported the iterator exits cleanly via ENOSYS */
+	if (WIFEXITED(status) && WEXITSTATUS(status) == PIDFD_SKIP) {
+		munmap(map, page_size);
+		SKIP(return, "listns() not supported");
+	}
+
 	/* Should have been killed */
 	ASSERT_TRUE(WIFSIGNALED(status));
 	ASSERT_EQ(WTERMSIG(status), SIGKILL);
diff --git a/tools/testing/selftests/namespaces/nsid_test.c b/tools/testing/selftests/namespaces/nsid_test.c
index b4a14c6693a5..46dc838cba82 100644
--- a/tools/testing/selftests/namespaces/nsid_test.c
+++ b/tools/testing/selftests/namespaces/nsid_test.c
@@ -25,14 +25,24 @@
 /* Fixture for tests that create child processes */
 FIXTURE(nsid) {
 	pid_t child_pid;
+	pid_t grandchild_pid;
 };
 
 FIXTURE_SETUP(nsid) {
 	self->child_pid = 0;
+	self->grandchild_pid = 0;
 }
 
 FIXTURE_TEARDOWN(nsid) {
-	/* Clean up any child process that may still be running */
+	/*
+	 * Kill grandchild first: timens_separate and pidns_separate fork a
+	 * grandchild that calls pause().  It is reparented to init on child
+	 * exit and keeps the test runner's tap pipe open, hanging the runner.
+	 */
+	if (self->grandchild_pid > 0) {
+		kill(self->grandchild_pid, SIGKILL);
+		waitpid(self->grandchild_pid, NULL, 0);
+	}
 	if (self->child_pid > 0) {
 		kill(self->child_pid, SIGKILL);
 		waitpid(self->child_pid, NULL, 0);
@@ -676,6 +686,7 @@ TEST_F(nsid, timens_separate)
 
 	pid_t grandchild_pid;
 	ASSERT_EQ(read(pipefd[0], &grandchild_pid, sizeof(grandchild_pid)), sizeof(grandchild_pid));
+	self->grandchild_pid = grandchild_pid;
 	close(pipefd[0]);
 
 	/* Open grandchild's time namespace */
@@ -797,6 +808,7 @@ TEST_F(nsid, pidns_separate)
 
 	pid_t grandchild_pid;
 	ASSERT_EQ(read(pipefd[0], &grandchild_pid, sizeof(grandchild_pid)), sizeof(grandchild_pid));
+	self->grandchild_pid = grandchild_pid;
 	close(pipefd[0]);
 
 	/* Open grandchild's PID namespace */