* [PATCH bpf] selftests/bpf: test_progs: fix client/server race in tcp_rtt
@ 2019-09-20 23:30 Stanislav Fomichev
2019-09-22 21:03 ` Andrii Nakryiko
0 siblings, 1 reply; 4+ messages in thread
From: Stanislav Fomichev @ 2019-09-20 23:30 UTC (permalink / raw)
To: netdev, bpf; +Cc: davem, ast, daniel, Stanislav Fomichev
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 <sdf@google.com>
---
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);
+
CHECK_FAIL(run_test(cgroup_fd, server_fd));
close(server_fd);
close_cgroup_fd:
--
2.23.0.351.gc4317032e6-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH bpf] selftests/bpf: test_progs: fix client/server race in tcp_rtt
2019-09-20 23:30 [PATCH bpf] selftests/bpf: test_progs: fix client/server race in tcp_rtt Stanislav Fomichev
@ 2019-09-22 21:03 ` Andrii Nakryiko
2019-09-23 15:38 ` Stanislav Fomichev
0 siblings, 1 reply; 4+ messages in thread
From: Andrii Nakryiko @ 2019-09-22 21:03 UTC (permalink / raw)
To: Stanislav Fomichev
Cc: Networking, bpf, David S. Miller, Alexei Starovoitov,
Daniel Borkmann
On Sun, Sep 22, 2019 at 12:10 PM Stanislav Fomichev <sdf@google.com> 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 <sdf@google.com>
> ---
> 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
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH bpf] selftests/bpf: test_progs: fix client/server race in tcp_rtt
2019-09-22 21:03 ` Andrii Nakryiko
@ 2019-09-23 15:38 ` Stanislav Fomichev
2019-09-23 16:41 ` Andrii Nakryiko
0 siblings, 1 reply; 4+ messages in thread
From: Stanislav Fomichev @ 2019-09-23 15:38 UTC (permalink / raw)
To: Andrii Nakryiko
Cc: Stanislav Fomichev, Networking, bpf, David S. Miller,
Alexei Starovoitov, Daniel Borkmann
On 09/22, Andrii Nakryiko wrote:
> On Sun, Sep 22, 2019 at 12:10 PM Stanislav Fomichev <sdf@google.com> 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 <sdf@google.com>
> > ---
> > 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?
Good point. How about I do the same thing I do in sockopt_inherit tests:
https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/tree/tools/testing/selftests/bpf/prog_tests/sockopt_inherit.c#n73
err = listen()
pthread_cond_signal()
if (CHECK_FAIL(err)) {
return;
}
Should fix the problem of getting stuck forever without any timeouts.
I'll send a v2 later today.
> > +
> > CHECK_FAIL(run_test(cgroup_fd, server_fd));
> > close(server_fd);
> > close_cgroup_fd:
> > --
> > 2.23.0.351.gc4317032e6-goog
> >
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH bpf] selftests/bpf: test_progs: fix client/server race in tcp_rtt
2019-09-23 15:38 ` Stanislav Fomichev
@ 2019-09-23 16:41 ` Andrii Nakryiko
0 siblings, 0 replies; 4+ messages in thread
From: Andrii Nakryiko @ 2019-09-23 16:41 UTC (permalink / raw)
To: Stanislav Fomichev
Cc: Stanislav Fomichev, Networking, bpf, David S. Miller,
Alexei Starovoitov, Daniel Borkmann
On Mon, Sep 23, 2019 at 8:38 AM Stanislav Fomichev <sdf@fomichev.me> wrote:
>
> On 09/22, Andrii Nakryiko wrote:
> > On Sun, Sep 22, 2019 at 12:10 PM Stanislav Fomichev <sdf@google.com> 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 <sdf@google.com>
> > > ---
> > > 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?
> Good point. How about I do the same thing I do in sockopt_inherit tests:
> https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/tree/tools/testing/selftests/bpf/prog_tests/sockopt_inherit.c#n73
>
> err = listen()
> pthread_cond_signal()
> if (CHECK_FAIL(err)) {
> return;
> }
>
> Should fix the problem of getting stuck forever without any timeouts.
> I'll send a v2 later today.
Sounds good.
>
> > > +
> > > CHECK_FAIL(run_test(cgroup_fd, server_fd));
> > > close(server_fd);
> > > close_cgroup_fd:
> > > --
> > > 2.23.0.351.gc4317032e6-goog
> > >
^ permalink raw reply [flat|nested] 4+ messages in thread
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2019-09-20 23:30 [PATCH bpf] selftests/bpf: test_progs: fix client/server race in tcp_rtt Stanislav Fomichev
2019-09-22 21:03 ` Andrii Nakryiko
2019-09-23 15:38 ` Stanislav Fomichev
2019-09-23 16:41 ` Andrii Nakryiko
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