From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.7 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0DCD8C3A5A6 for ; Sun, 22 Sep 2019 21:04:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D457B208C0 for ; Sun, 22 Sep 2019 21:04:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="gF5tS84s" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392382AbfIVVEH (ORCPT ); Sun, 22 Sep 2019 17:04:07 -0400 Received: from mail-qt1-f194.google.com ([209.85.160.194]:44436 "EHLO mail-qt1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388636AbfIVVEG (ORCPT ); Sun, 22 Sep 2019 17:04:06 -0400 Received: by mail-qt1-f194.google.com with SMTP id u40so14862901qth.11; Sun, 22 Sep 2019 14:04:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=oFRwkLtn2Iq4ic5glemRgq9T0csDPXP20ndx8eWwKH0=; b=gF5tS84sfuj26rxAmSD8tXZJzlv6RZCDEVucrdGf8m0OWJKWJ92C2q2hEULVxN//0j pnB0lKgouLiw87AbMdE52dcwgu9lpR2FzQ6/23ADtr0vB2tysPU2UIBGfQKjU4QNEg4h V6x6H8KFXrz1EAtsOpDRtCXOgnWzZ9UOwgGvD5xYU45Cwfa0y22e/LS4VX3/73VJkagA JVXGVCOW/lDhPDi81cnyoDbJlYvDDcL6ot4f8R5V7mS1AzCBmY1ricrZNbN+nNZ9bAcj TzvhQ8qSeOWv+dhuZm0prpbGjUvOwrFi5wNf5i2Jcy1cy6+9IpW1e5uyMSEWThEjKyhK RITA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=oFRwkLtn2Iq4ic5glemRgq9T0csDPXP20ndx8eWwKH0=; b=G1WitvnRrdxT1ybbwim3aGzfH4qpNqwTNWjBR11RKtfB4FqJ9XIYluePwcQG+0FlcY Jc9GJ0BPIv39U+OjExt4MoYAY6xLTdqijcQSfqlldurB0/czDPrl9UEzFOtYwej5t2ZE F3lw5suwPrO26Qb2gkmHb1iBcdh+KXVvRzHnsB70H4UnUAIQeomTyeN49Yky1HmQbR9a TVLn6SsnJFS9sNJVEQmrbTr86ZhxeFKHvGRuwOvx4LYbXnYsltC2g4iz4snBXSGPbAq3 SZKx84Io9Wsl5fruqca+e6lbI33EJymleaMwxeWVtFJ0g2lvXVNnEeiecjz8zfLbzOPc ol5w== X-Gm-Message-State: APjAAAUhFKkJVM0BoTvvzl70wNjBfeMrTkN6TMZC63L7sauDnDzHeDuk /uMnxhTs2BTHSKsOtmPOM1SYbVENaLDdN4Ktofs= X-Google-Smtp-Source: APXvYqyOpM+WkAYatt7DzG/e4cFwk8OrxFjR+ycVMRb4cWpvcmoLJd0M3UQroa0ZOGu4FyW2oIRT3GdU+X0W5vULxJU= X-Received: by 2002:ac8:5147:: with SMTP id h7mr14139172qtn.117.1569186245693; Sun, 22 Sep 2019 14:04:05 -0700 (PDT) MIME-Version: 1.0 References: <20190920233019.187498-1-sdf@google.com> In-Reply-To: <20190920233019.187498-1-sdf@google.com> From: Andrii Nakryiko Date: Sun, 22 Sep 2019 14:03:54 -0700 Message-ID: Subject: Re: [PATCH bpf] selftests/bpf: test_progs: fix client/server race in tcp_rtt To: Stanislav Fomichev Cc: Networking , bpf , "David S. Miller" , Alexei Starovoitov , Daniel Borkmann Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Sun, Sep 22, 2019 at 12:10 PM Stanislav Fomichev wrote: > > This is the same problem I found earlier in test_sockopt_inherit: > there is a race between server thread doing accept() and client > thread doing connect(). Let's explicitly synchronize them via > pthread conditional variable. > > Fixes: b55873984dab ("selftests/bpf: test BPF_SOCK_OPS_RTT_CB") > Signed-off-by: Stanislav Fomichev > --- > tools/testing/selftests/bpf/prog_tests/tcp_rtt.c | 16 +++++++++++++++- > 1 file changed, 15 insertions(+), 1 deletion(-) > > diff --git a/tools/testing/selftests/bpf/prog_tests/tcp_rtt.c b/tools/testing/selftests/bpf/prog_tests/tcp_rtt.c > index fdc0b3614a9e..e64058906bcd 100644 > --- a/tools/testing/selftests/bpf/prog_tests/tcp_rtt.c > +++ b/tools/testing/selftests/bpf/prog_tests/tcp_rtt.c > @@ -203,6 +203,9 @@ static int start_server(void) > return fd; > } > > +static pthread_mutex_t server_started_mtx = PTHREAD_MUTEX_INITIALIZER; > +static pthread_cond_t server_started = PTHREAD_COND_INITIALIZER; > + > static void *server_thread(void *arg) > { > struct sockaddr_storage addr; > @@ -215,6 +218,10 @@ static void *server_thread(void *arg) > return NULL; > } > > + pthread_mutex_lock(&server_started_mtx); > + pthread_cond_signal(&server_started); > + pthread_mutex_unlock(&server_started_mtx); > + > client_fd = accept(fd, (struct sockaddr *)&addr, &len); > if (CHECK_FAIL(client_fd < 0)) { > perror("Failed to accept client"); > @@ -248,7 +255,14 @@ void test_tcp_rtt(void) > if (CHECK_FAIL(server_fd < 0)) > goto close_cgroup_fd; > > - pthread_create(&tid, NULL, server_thread, (void *)&server_fd); > + if (CHECK_FAIL(pthread_create(&tid, NULL, server_thread, > + (void *)&server_fd))) > + goto close_cgroup_fd; > + > + pthread_mutex_lock(&server_started_mtx); > + pthread_cond_wait(&server_started, &server_started_mtx); > + pthread_mutex_unlock(&server_started_mtx); If the server fails to listen, then we'll never get a signal, right? Let's use timedwait instead to avoid test getting stuck forever in such cases? > + > CHECK_FAIL(run_test(cgroup_fd, server_fd)); > close(server_fd); > close_cgroup_fd: > -- > 2.23.0.351.gc4317032e6-goog >