diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index 38f651469968..be0fece2596d 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -4037,6 +4037,16 @@ TEST(user_notification_filter_empty_threaded)
 	EXPECT_GT((pollfd.revents & POLLHUP) ?: 0, 0);
 }
 
+
+int get_next_fd(int prev_fd)
+{
+	for (int i = prev_fd + 1; i < FD_SETSIZE; ++i) {
+		if (fcntl(i, F_GETFD) == -1)
+			return i;
+	}
+	_exit(EXIT_FAILURE);
+}
+
 TEST(user_notification_addfd)
 {
 	pid_t pid;
@@ -4053,7 +4063,7 @@ TEST(user_notification_addfd)
 	/* There may be arbitrary already-open fds at test start. */
 	memfd = memfd_create("test", 0);
 	ASSERT_GE(memfd, 0);
-	nextfd = memfd + 1;
+	nextfd = get_next_fd(memfd);
 
 	ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
 	ASSERT_EQ(0, ret) {
@@ -4064,7 +4074,8 @@ TEST(user_notification_addfd)
 	/* Check that the basic notification machinery works */
 	listener = user_notif_syscall(__NR_getppid,
 				      SECCOMP_FILTER_FLAG_NEW_LISTENER);
-	ASSERT_EQ(listener, nextfd++);
+	ASSERT_EQ(listener, nextfd);
+	nextfd = get_next_fd(nextfd);
 
 	pid = fork();
 	ASSERT_GE(pid, 0);
@@ -4119,14 +4130,16 @@ TEST(user_notification_addfd)
 
 	/* Verify we can set an arbitrary remote fd */
 	fd = ioctl(listener, SECCOMP_IOCTL_NOTIF_ADDFD, &addfd);
-	EXPECT_EQ(fd, nextfd++);
+	EXPECT_EQ(fd, nextfd);
+	nextfd = get_next_fd(nextfd);
 	EXPECT_EQ(filecmp(getpid(), pid, memfd, fd), 0);
 
 	/* Verify we can set an arbitrary remote fd with large size */
 	memset(&big, 0x0, sizeof(big));
 	big.addfd = addfd;
 	fd = ioctl(listener, SECCOMP_IOCTL_NOTIF_ADDFD_BIG, &big);
-	EXPECT_EQ(fd, nextfd++);
+	EXPECT_EQ(fd, nextfd);
+	nextfd = get_next_fd(nextfd);
 
 	/* Verify we can set a specific remote fd */
 	addfd.newfd = 42;
@@ -4164,7 +4177,8 @@ TEST(user_notification_addfd)
 	 * Child has earlier "low" fds and now 42, so we expect the next
 	 * lowest available fd to be assigned here.
 	 */
-	EXPECT_EQ(fd, nextfd++);
+	EXPECT_EQ(fd, nextfd);
+	nextfd = get_next_fd(nextfd);
 	ASSERT_EQ(filecmp(getpid(), pid, memfd, fd), 0);
 
 	/*