From 94c2f50b61258381abcd3a33fd5f2bc87e26df11 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Fri, 13 Mar 2020 18:39:30 -0700 Subject: [PATCH] selftests/bpf: Fix race in tcp_rtt test Previous attempt to make tcp_rtt more robust introduced a new race, in which server_done might be set to true before server can actually accept any connection. Fix this by unconditionally waiting for accept(). Given socket is non-blocking, if there are any problems with client side, it should eventually close listening FD and let server thread exit with failure. Fixes: 4cd729fa022c ("selftests/bpf: Make tcp_rtt test more robust to failures") Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/bpf/20200314013932.4035712-1-andriin@fb.com --- tools/testing/selftests/bpf/prog_tests/tcp_rtt.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/tcp_rtt.c b/tools/testing/selftests/bpf/prog_tests/tcp_rtt.c index e08f6bb..e56b52a 100644 --- a/tools/testing/selftests/bpf/prog_tests/tcp_rtt.c +++ b/tools/testing/selftests/bpf/prog_tests/tcp_rtt.c @@ -226,7 +226,7 @@ static void *server_thread(void *arg) return ERR_PTR(err); } - while (!server_done) { + while (true) { client_fd = accept(fd, (struct sockaddr *)&addr, &len); if (client_fd == -1 && errno == EAGAIN) { usleep(50); @@ -272,7 +272,7 @@ void test_tcp_rtt(void) CHECK_FAIL(run_test(cgroup_fd, server_fd)); server_done = true; - pthread_join(tid, &server_res); + CHECK_FAIL(pthread_join(tid, &server_res)); CHECK_FAIL(IS_ERR(server_res)); close_server_fd: -- 2.7.4